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Sample records for include additional nitrogen

  1. Options for including nitrogen management in climate policy

    International Nuclear Information System (INIS)

    Erisman, J.W.

    2010-12-01

    The outline of the presentation is as follows: Climate change and nitrogen; Nitrogen and climate interlinkages; Options for nitrogen management; Report, workshop and IPCC; and Conclusions. The concluding remarks are: Fertilizing the biosphere with reactive nitrogen compounds lead to ecosystem, health, water and climate impacts; Nitrogen deposition can lead to additional carbon sequestration and to impacts on biodiversity and ecosystem services; Nitrogen addition to the biosphere might have a net cooling effect of 1 W/m 2 ; Life Cycle Analysis is needed to show the full impact; and Nitrogen management is essential for the environment and can have a positive effect on the net GHG exchange.

  2. Photoactive devices including porphyrinoids with coordinating additives

    Science.gov (United States)

    Forrest, Stephen R; Zimmerman, Jeramy; Yu, Eric K; Thompson, Mark E; Trinh, Cong; Whited, Matthew; Diev, Vlacheslav

    2015-05-12

    Coordinating additives are included in porphyrinoid-based materials to promote intermolecular organization and improve one or more photoelectric characteristics of the materials. The coordinating additives are selected from fullerene compounds and organic compounds having free electron pairs. Combinations of different coordinating additives can be used to tailor the characteristic properties of such porphyrinoid-based materials, including porphyrin oligomers. Bidentate ligands are one type of coordinating additive that can form coordination bonds with a central metal ion of two different porphyrinoid compounds to promote porphyrinoid alignment and/or pi-stacking. The coordinating additives can shift the absorption spectrum of a photoactive material toward higher wavelengths, increase the external quantum efficiency of the material, or both.

  3. Nitrogen oxide abatement by distributed fuel addition

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J.O.L.; Mereb, J.B.

    1991-09-20

    Reburning is examined as a means of NO{sub x} destruction in a 17 kW down-fired pulverized coal combustor. In reburning, a secondary fuel is introduced downstream of the primary flame to produce a reducing zone, favorable to NO destruction, and air is introduced further downstream to complete the combustion. Emphasis is on natural gas reburning and a bituminous coal primary flame. A parametric examination of reburning employing a statistical experimental design, is conducted, complemented by detailed experiments. Mechanisms governing the inter-conversion of nitrogenous species in the fuel rich reburn zone is explored. The effect of reburning on N{sub 2}O emissions, the effect of primary flame mode (premixed and diffusion) and the effect of distributing the reburning fuel, are also investigated.

  4. Kinetics of irreversible thermal decomposition of dissociating nitrogen dioxide with nitrogen oxide or oxygen additions

    International Nuclear Information System (INIS)

    Gvozdev, A.A.

    1987-01-01

    The effect of NO or O 2 admixtures on kinetics of the irreversible thermal decomposition of nitrogen dioxide at temperatures 460-520 deg C and pressures 4-7 MPa has been studied. It follows from experimental data that the rate of N 2 O 4 formation reduces with the increase of partial pressure of oxygen or decrease of partial pressure of nitrogen oxide. The same regularity is seen for the rate of nitrogen formation. The rate constants of N 2 O formation in dissociating nitrogen tetroxide with oxygen or nitrogen oxide additions agree satisfactorily with previously published results, obtained in stoichiometric mixtures. The appreciable discrepancy at 520 deg C is bind with considerable degree of nitrogen oxide transformation which constitutes approximately 14%. It is determined that the kinetics of formation of the products of irreversible N 2 O and N 2 decomposition in stoichiometric and non-stoichiometric 2NO 2 ↔ 2NO+O 2 mixtures is described by identical 3NO → N 2 O+NO 2 and N 2 O+NO → N 2 +NO 2 reactions

  5. Minor Stimulation of Soil Carbon Storage by Nitrogen Addition

    Science.gov (United States)

    Luo, Y.; Lu, M.; Zhou, X.; Li, B.; Fang, C.; Chen, J.

    2009-04-01

    Anthropogenic nitrogen (N) fertilization and deposition adds 292 Tg N each year, largely to terrestrial ecosystems. N addition usually stimulates biomass growth and results in increases in plant carbon (C) pool sizes. Whether this stimulated biomass growth would lead to increased C storage in soils - the largest pool in the land - is a critical issue for the mitigation of climate change. Fossil fuel burning and deforestation emit about 10 Gt C per year to the atmosphere. Global analysis has shown that terrestrial ecosystems absorb a substantial portion of emitted C. If N addition is one key mechanism underlying contemporary terrestrial C sequestration, the land C sink would be likely to be enhanced as N deposition and fertilization are anticipated to increase in the future. However, impacts of C addition on soil C sequestration remain highly controversial. To reveal a central tendency, we synthesized results from nearly 300 studies. Our analysis showed that N addition did not significantly stimulate soil C storage in nonagricultural ecosystems (e.g., forests and grasslands) but significantly in agricultural ecosystems. Averaged effects of N addition on soil C storage were minor across all ecosystems. N-induced changes in soil C stocks were significantly regulated by soil C:N. Nitrogen addition tends to stimulate C storage in low C:N soil but increase C loss in high C:N soil. Our results indicate that N stimulation of C storage primarily occurs in plant pools but is highly limited in soil pools.

  6. Grassland biodiversity bounces back from long-term nitrogen addition.

    Science.gov (United States)

    Storkey, J; Macdonald, A J; Poulton, P R; Scott, T; Köhler, I H; Schnyder, H; Goulding, K W T; Crawley, M J

    2015-12-17

    The negative effect of increasing atmospheric nitrogen (N) pollution on grassland biodiversity is now incontrovertible. However, the recent introduction of cleaner technologies in the UK has led to reductions in the emissions of nitrogen oxides, with concomitant decreases in N deposition. The degree to which grassland biodiversity can be expected to 'bounce back' in response to these improvements in air quality is uncertain, with a suggestion that long-term chronic N addition may lead to an alternative low biodiversity state. Here we present evidence from the 160-year-old Park Grass Experiment at Rothamsted Research, UK, that shows a positive response of biodiversity to reducing N addition from either atmospheric pollution or fertilizers. The proportion of legumes, species richness and diversity increased across the experiment between 1991 and 2012 as both wet and dry N deposition declined. Plots that stopped receiving inorganic N fertilizer in 1989 recovered much of the diversity that had been lost, especially if limed. There was no evidence that chronic N addition has resulted in an alternative low biodiversity state on the Park Grass plots, except where there has been extreme acidification, although it is likely that the recovery of plant communities has been facilitated by the twice-yearly mowing and removal of biomass. This may also explain why a comparable response of plant communities to reduced N inputs has yet to be observed in the wider landscape.

  7. Quantifying nitrogen leaching response to fertilizer additions in China's cropland.

    Science.gov (United States)

    Gao, Shuoshuo; Xu, Peng; Zhou, Feng; Yang, Hui; Zheng, Chunmiao; Cao, Wei; Tao, Shu; Piao, Shilong; Zhao, Yue; Ji, Xiaoyan; Shang, Ziyin; Chen, Minpeng

    2016-04-01

    Agricultural soils account for more than 50% of nitrogen leaching (LN) to groundwater in China. When excess levels of nitrogen accumulate in groundwater, it poses a risk of adverse health effects. Despite this recognition, estimation of LN from cropland soils in a broad spatial scale is still quite uncertain in China. The uncertainty of LN primarily stems from the shape of nitrogen leaching response to fertilizer additions (N rate) and the role of environmental conditions. On the basis of 453 site-years at 51 sites across China, we explored the nonlinearity and variability of the response of LN to N rate and developed an empirical statistical model to determine how environmental factors regulate the rate of N leaching (LR). The result shows that LN-N rate relationship is convex for most crop types, and varies by local hydro-climates and soil organic carbon. Variability of air temperature explains a half (∼ 52%) of the spatial variation of LR. The results of model calibration and validation indicate that incorporating this empirical knowledge into a predictive model could accurately capture the variation in leaching and produce a reasonable upscaling from site to country. The fertilizer-induced LN in 2008 for China's cropland were 0.88 ± 0.23 TgN (1σ), significantly lower than the linear or uniform model, as assumed by Food and Agriculture Organization and MITERRA-EUROPE models. These results also imply that future policy to reduce N leaching from cropland needs to consider environmental variability rather than solely attempt to reduce N rate. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Responses of ecosystem nitrogen cycle to nitrogen addition: a meta-analysis.

    Science.gov (United States)

    Lu, Meng; Yang, Yuanhe; Luo, Yiqi; Fang, Changming; Zhou, Xuhui; Chen, Jiakuan; Yang, Xin; Li, Bo

    2011-03-01

    • Anthropogenic nitrogen (N) addition may substantially alter the terrestrial N cycle. However, a comprehensive understanding of how the ecosystem N cycle responds to external N input remains elusive. • Here, we evaluated the central tendencies of the responses of 15 variables associated with the ecosystem N cycle to N addition, using data extracted from 206 peer-reviewed papers. • Our results showed that the largest changes in the ecosystem N cycle caused by N addition were increases in soil inorganic N leaching (461%), soil NO₃⁻ concentration (429%), nitrification (154%), nitrous oxide emission (134%), and denitrification (84%). N addition also substantially increased soil NH₄+ concentration (47%), and the N content in belowground (53%) and aboveground (44%) plant pools, leaves (24%), litter (24%) and dissolved organic N (21%). Total N content in the organic horizon (6.1%) and mineral soil (6.2%) slightly increased in response to N addition. However, N addition induced a decrease in microbial biomass N by 5.8%. • The increases in N effluxes caused by N addition were much greater than those in plant and soil pools except soil NO₃⁻, suggesting a leaky terrestrial N system. © 2010 The Authors. New Phytologist © 2010 New Phytologist Trust.

  9. Nitrogen

    Science.gov (United States)

    Apodaca, Lori E.

    2013-01-01

    The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

  10. Nitrogen addition enhances drought sensitivity of young deciduous tree species

    Directory of Open Access Journals (Sweden)

    Christoph Dziedek

    2016-07-01

    Full Text Available Understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. Although there is evidence on the mode of nitrogen (N and drought (D effects on tree growth, our understanding of the interplay of these factors is still limited. Simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of N addition and D on the productivity of three tree species (Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii in relation to functional diverse species mixtures using data from a four-year field experiment in Northwest Germany. Here we show that species mixing can mitigate the negative effects of combined N fertilization and D events, but the community response is mainly driven by the combination of certain traits rather than the tree species richness of a community. For beech, we found that negative effects of D on growth rates were amplified by N fertilization (i.e. combined treatment effects were non-additive, while for oak and fir, the simultaneous effects of N and D were additive. Beech and oak were identified as most sensitive to combined N+D effects with a strong size-dependency observed for beech, suggesting that the negative impact of N+D becomes stronger with time as beech grows larger. As a consequence, the net biodiversity effect declined at the community level, which can be mainly assigned to a distinct loss of complementarity in beech-oak mixtures. This pattern, however, was not evident in the other species-mixtures, indicating that neighborhood composition (i.e. trait combination, but not tree species richness mediated the relationship between tree diversity and treatment effects on tree growth. Our findings point to the importance of the qualitative role (‘trait portfolio’ that biodiversity play in determining resistance of diverse tree communities to environmental changes. As such, they

  11. Nutrient additions in pristine Patagonian Sphagnum bog vegetation: can phosphorus addition alleviate (the effects of) increased nitrogen loads.

    Science.gov (United States)

    Fritz, C; van Dijk, G; Smolders, A J P; Pancotto, V A; Elzenga, T J T M; Roelofs, J G M; Grootjans, A P

    2012-05-01

    Sphagnum-bog ecosystems have a limited capability to retain carbon and nutrients when subjected to increased nitrogen (N) deposition. Although it has been proposed that phosphorus (P) can dilute negative effects of nitrogen by increasing biomass production of Sphagnum mosses, it is still unclear whether P-addition can alleviate physiological N-stress in Sphagnum plants. A 3-year fertilisation experiment was conducted in lawns of a pristine Sphagnum magellanicum bog in Patagonia, where competing vascular plants were practically absent. Background wet deposition of nitrogen was low (≈ 0.1-0.2 g · N · m(-2) · year(-1)). Nitrogen (4 g · N · m(-2) · year(-1)) and phosphorus (1 g · P · m(-2) · year(-1)) were applied, separately and in combination, six times during the growing season. P-addition substantially increased biomass production of Sphagnum. Nitrogen and phosphorus changed the morphology of Sphagnum mosses by enhancing height increment, but lowering moss stem density. In contrast to expectations, phosphorus failed to alleviate physiological stress imposed by excess nitrogen (e.g. amino acid accumulation, N-saturation and decline in photosynthetic rates). We conclude that despite improving growth conditions by P-addition, Sphagnum-bog ecosystems remain highly susceptible to nitrogen additions. Increased susceptibility to desiccation by nutrients may even worsen the negative effects of excess nitrogen especially in windy climates like in Patagonia. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

  12. Long-term nitrogen addition decreases carbon leaching in a nitrogen-rich forest ecosystem

    Directory of Open Access Journals (Sweden)

    X. Lu

    2013-06-01

    Full Text Available Dissolved organic carbon (DOC plays a critical role in the carbon (C cycle of forest soils, and has been recently connected with global increases in nitrogen (N deposition. Most studies on effects of elevated N deposition on DOC have been carried out in N-limited temperate regions, with far fewer data available from N-rich ecosystems, especially in the context of chronically elevated N deposition. Furthermore, mechanisms for excess N-induced changes of DOC dynamics have been suggested to be different between the two kinds of ecosystems, because of the different ecosystem N status. The purpose of this study was to experimentally examine how long-term N addition affects DOC dynamics below the primary rooting zones (the upper 20 cm soils in typically N-rich lowland tropical forests. We have a primary assumption that long-term continuous N addition minimally affects DOC concentrations and effluxes in N-rich tropical forests. Experimental N addition was administered at the following levels: 0, 50, 100 and 150 kg N ha−1 yr−1, respectively. Results showed that seven years of N addition significantly decreased DOC concentrations in soil solution, and chemo-physical controls (solution acidity change and soil sorption rather than biological controls may mainly account for the decreases, in contrast to other forests. We further found that N addition greatly decreased annual DOC effluxes from the primary rooting zone and increased water-extractable DOC in soils. Our results suggest that long-term N deposition could increase soil C sequestration in the upper soils by decreasing DOC efflux from that layer in N-rich ecosystems, a novel mechanism for continued accumulation of soil C in old-growth forests.

  13. Elevated CO2 promotes long-term nitrogen accumulation only in combination with nitrogen addition.

    Science.gov (United States)

    Pastore, Melissa A; Megonigal, J Patrick; Langley, J Adam

    2016-01-01

    Biogeochemical models that incorporate nitrogen (N) limitation indicate that N availability will control the magnitude of ecosystem carbon uptake in response to rising CO2 . Some models, however, suggest that elevated CO2 may promote ecosystem N accumulation, a feedback that in the long term could circumvent N limitation of the CO2 response while mitigating N pollution. We tested this prediction using a nine-year CO2 xN experiment in a tidal marsh. Although the effects of CO2 are similar between uplands and wetlands in many respects, this experiment offers a greater likelihood of detecting CO2 effects on N retention on a decadal timescale because tidal marshes have a relatively open N cycle and can accrue soil organic matter rapidly. To determine how elevated CO2 affects N dynamics, we assessed the three primary fates of N in a tidal marsh: (1) retention in plants and soil, (2) denitrification to the atmosphere, and (3) tidal export. We assessed changes in N pools and tracked the fate of a (15) N tracer added to each plot in 2006 to quantify the fraction of added N retained in vegetation and soil, and to estimate lateral N movement. Elevated CO2 alone did not increase plant N mass, soil N mass, or (15) N label retention. Unexpectedly, CO2 and N interacted such that the combined N+CO2 treatment increased ecosystem N accumulation despite the stimulation in N losses indicated by reduced (15) N label retention. These findings suggest that in N-limited ecosystems, elevated CO2 is unlikely to increase long-term N accumulation and circumvent progressive N limitation without additional N inputs, which may relieve plant-microbe competition and allow for increased plant N uptake. © 2015 John Wiley & Sons Ltd.

  14. Delayed addition of nitrogen-rich substrates during composting of municipal waste

    DEFF Research Database (Denmark)

    Nigatu, Abebe Nigussie; Bruun, Sander; Kuyper, Thomas W.

    2017-01-01

    that split addition of the nitrogen-rich substrate reduced nitrogen losses by 9% when sawdust was used and 20% when coffee husks were used as the bulking agent. Depending on the bulking agent used, split addition increased cumulative N2O emissions by 400-600% compared to single addition. In contrast, single......-rich substrate (poultry manure) on nitrogen losses and greenhouse gas emissions during composting and to link this effect to different bulking agents (coffee husks and sawdust), and (ii) to assess the effect of split addition of a nitrogen-rich substrate on compost stability and sanitisation. The results showed...... addition increased methane emissions by up to 50% compared to split addition of the substrate. Hence, the timing of the addition of the N-rich substrate had only a marginal effect on total non-CO2 greenhouse gas emissions. Split addition of the N-rich substrate resulted in compost that was just as stable...

  15. Nitrogen oxide abatement by distributed fuel addition. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J.O.L.; Mereb, J.B.

    1991-09-20

    Reburning is examined as a means of NO{sub x} destruction in a 17 kW down-fired pulverized coal combustor. In reburning, a secondary fuel is introduced downstream of the primary flame to produce a reducing zone, favorable to NO destruction, and air is introduced further downstream to complete the combustion. Emphasis is on natural gas reburning and a bituminous coal primary flame. A parametric examination of reburning employing a statistical experimental design, is conducted, complemented by detailed experiments. Mechanisms governing the inter-conversion of nitrogenous species in the fuel rich reburn zone is explored. The effect of reburning on N{sub 2}O emissions, the effect of primary flame mode (premixed and diffusion) and the effect of distributing the reburning fuel, are also investigated.

  16. Change in gene abundance in the nitrogen biogeochemical cycle with temperature and nitrogen addition in Antarctic soils.

    Science.gov (United States)

    Jung, Jaejoon; Yeom, Jinki; Kim, Jisun; Han, Jiwon; Lim, Hyoun Soo; Park, Hyun; Hyun, Seunghun; Park, Woojun

    2011-12-01

    The microbial community (bacterial, archaeal, and fungi) and eight genes involved in the nitrogen biogeochemical cycle (nifH, nitrogen fixation; bacterial and archaeal amoA, ammonia oxidation; narG, nitrate reduction; nirS, nirK, nitrite reduction; norB, nitric oxide reduction; and nosZ, nitrous oxide reduction) were quantitatively assessed in this study, via real-time PCR with DNA extracted from three Antarctic soils. Interestingly, AOB amoA was found to be more abundant than AOA amoA in Antarctic soils. The results of microcosm studies revealed that the fungal and archaeal communities were diminished in response to warming temperatures (10 °C) and that the archaeal community was less sensitive to nitrogen addition, which suggests that those two communities are well-adapted to colder temperatures. AOA amoA and norB genes were reduced with warming temperatures. The abundance of only the nifH and nirK genes increased with both warming and the addition of nitrogen. NirS-type denitrifying bacteria outnumbered NirK-type denitrifiers regardless of the treatment used. Interestingly, dramatic increases in both NirS and NirK-types denitrifiers were observed with nitrogen addition. NirK types increase with warming, but NirS-type denitrifiers tend to be less sensitive to warming. Our findings indicated that the Antarctic microbial nitrogen cycle could be dramatically altered by temperature and nitrogen, and that warming may be detrimental to the ammonia-oxidizing archaeal community. To the best of our knowledge, this is the first report to investigate genes associated with each process of the nitrogen biogeochemical cycle in an Antarctic terrestrial soil environment. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  17. Effects of soil warming and nitrogen addition on soil respiration in a New Zealand tussock grassland.

    Science.gov (United States)

    Graham, Scott L; Hunt, John E; Millard, Peter; McSeveny, Tony; Tylianakis, Jason M; Whitehead, David

    2014-01-01

    Soil respiration (RS) represents a large terrestrial source of CO2 to the atmosphere. Global change drivers such as climate warming and nitrogen deposition are expected to alter the terrestrial carbon cycle with likely consequences for RS and its components, autotrophic (RA) and heterotrophic respiration (RH). Here we investigate the impacts of a 3°C soil warming treatment and a 50 kg ha(-1) y(-1) nitrogen addition treatment on RS, RH and their respective seasonal temperature responses in an experimental tussock grassland. Average respiration in untreated soils was 0.96±0.09 μmol m(-2) s(-1) over the course of the experiment. Soil warming and nitrogen addition increased RS by 41% and 12% respectively. These treatment effects were additive under combined warming and nitrogen addition. Warming increased RH by 37% while nitrogen addition had no effect. Warming and nitrogen addition affected the seasonal temperature response of RS by increasing the basal rate of respiration (R10) by 14% and 20% respectively. There was no significant interaction between treatments for R10. The treatments had no impact on activation energy (E0). The seasonal temperature response of RH was not affected by either warming or nitrogen addition. These results suggest that the additional CO2 emissions from New Zealand tussock grassland soils as a result of warming-enhanced RS constitute a potential positive feedback to rising atmospheric CO2 concentration.

  18. Influence of carbohydrate addition on nitrogen transformations and greenhouse gas emissions of intensive aquaculture system.

    Science.gov (United States)

    Hu, Zhen; Lee, Jae Woo; Chandran, Kartik; Kim, Sungpyo; Sharma, Keshab; Khanal, Samir Kumar

    2014-02-01

    Aquaculture is one of the fastest-growing segments of the food economy in modern times. It is also being considered as an important source of greenhouse gas (GHG) emissions. To date, limited studies have been conducted on GHG emissions from aquaculture system. In this study, daily addition of fish feed and soluble starch at a carbon-to-nitrogen (C/N) ratio of 16:1 (w/w) was used to examine the effects of carbohydrate addition on nitrogen transformations and GHG emissions in a zero-water exchange intensive aquaculture system. The addition of soluble starch stimulated heterotrophic bacterial growth and denitrification, which led to lower total ammonia nitrogen, nitrite and nitrate concentrations in aqueous phase. About 76.2% of the nitrogen output was emitted in the form of gaseous nitrogen (i.e., N2 and N2O) in the treatment tank (i.e., aquaculture tank with soluble starch addition), while gaseous nitrogen accounted for 33.3% of the nitrogen output in the control tank (i.e., aquaculture tank without soluble starch addition). Although soluble starch addition reduced daily N2O emissions by 83.4%, it resulted in an increase of daily carbon dioxide (CO2) emissions by 91.1%. Overall, starch addition did not contribute to controlling the GHG emissions from the aquaculture system. © 2013.

  19. Alteration of belowground carbon dynamics by nitrogen addition in southern California mixed conifer forests

    Science.gov (United States)

    N.S. Nowinski; S.E. Trumbore; G. Jimenez; M.E. Fenn

    2009-01-01

    Nitrogen deposition rates in southern California are the highest in North America and have had substantial effects on ecosystem functioning. We document changes in the belowground C cycle near ponderosa pine trees experiencing experimental nitrogen (N) addition (50 and 150 kg N ha−1 a−1 as slow release urea since 1997) at two end‐member...

  20. Soil carbon mineralization following biochar addition associated with external nitrogen

    Directory of Open Access Journals (Sweden)

    Rudong Zhao

    2015-12-01

    Full Text Available Biochar has been attracting increasing attention for its potentials of C sequestration and soil amendment. This study aimed to understand the effects of combining biochar with additional external N on soil C mineralization. A typical red soil (Plinthudults was treated with two biochars made from two types of plantation-tree trunks (soil-biochar treatments, and was also treated with external N (soil-biochar-N treatments. All treatments were incubated for 42 d. The CO2-C released from the treatments was detected periodically. After the incubation, soil properties such as pH, microbial biomass C (MBC, and microbial biomass N (MBN were measured. The addition of biochar with external N increased the soil pH (4.31-4.33 compared to the soil treated with external N only (4.21. This was not observed in the comparison of soil-biochar treatments (4.75-4.80 to soil only (4.74. Biochar additions (whether or not they were associated with external N increased soil MBC and MBN, but decreased CO2-C value per unit total C (added biochar C + soil C according to the model fitting. The total CO2-C released in soil-biochar treatments were enhanced compared to soil only (i.e., 3.15 vs. 2.57 mg and 3.23 vs. 2.45 mg, which was attributed to the labile C fractions in the biochars and through soil microorganism enhancement. However, there were few changes in soil C mineralization in soil-biochar-N treatments. Additionally, the potentially available C per unit total C in soil-biochar-N treatments was lower than that observed in the soil-biochar treatments. Therefore, we believe in the short term, that C mineralization in the soil can be enhanced by biochar addition, but not by adding external N concomitantly.

  1. Controlled Carbon Source Addition to an Alternating Nitrification-Denitrification Wastewater Treatment Process Including Biological P Removal

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens

    1995-01-01

    The paper investigates the effect of adding an external carbon source on the rate of denitrification in an alternating activated sludge process including biological P removal. Two carbon sources were examined, acetate and hydrolysate derived from biologically hydrolyzed sludge. Preliminary batch...... that external carbon source addition may serve as a suitable control variable to improve process performance....... process, the addition of either carbon source to the anoxic zone also resulted in an instantaneous and fairly reproducible increase in the denitrification rate. Some release of phosphate associated with the carbon source addition was observed. With respect to nitrogen removal, these results indicate...

  2. Effects of Water and Nitrogen Addition on Ecosystem Carbon Exchange in a Meadow Steppe

    Science.gov (United States)

    Wang, Yunbo; Jiang, Qi; Yang, Zhiming; Sun, Wei; Wang, Deli

    2015-01-01

    A changing precipitation regime and increasing nitrogen deposition are likely to have profound impacts on arid and semiarid ecosystem C cycling, which is often constrained by the timing and availability of water and nitrogen. However, little is known about the effects of altered precipitation and nitrogen addition on grassland ecosystem C exchange. We conducted a 3-year field experiment to assess the responses of vegetation composition, ecosystem productivity, and ecosystem C exchange to manipulative water and nitrogen addition in a meadow steppe. Nitrogen addition significantly stimulated aboveground biomass and net ecosystem CO2 exchange (NEE), which suggests that nitrogen availability is a primary limiting factor for ecosystem C cycling in the meadow steppe. Water addition had no significant impacts on either ecosystem C exchange or plant biomass, but ecosystem C fluxes showed a strong correlation with early growing season precipitation, rather than whole growing season precipitation, across the 3 experimental years. After we incorporated water addition into the calculation of precipitation regimes, we found that monthly average ecosystem C fluxes correlated more strongly with precipitation frequency than with precipitation amount. These results highlight the importance of precipitation distribution in regulating ecosystem C cycling. Overall, ecosystem C fluxes in the studied ecosystem are highly sensitive to nitrogen deposition, but less sensitive to increased precipitation. PMID:26010888

  3. Soil microbial responses to nitrogen addition in arid ecosystems

    Directory of Open Access Journals (Sweden)

    Robert L Sinsabaugh

    2015-08-01

    Full Text Available The N cycle of arid ecosystems is influenced by low soil organic matter, high soil pH and extremes in water potential and temperature that lead to open canopies and development of biological soil crusts (biocrusts. We investigated the effects of N amendment on soil microbial dynamics in a Larrea tridentata-Ambrosia dumosa shrubland site in southern Nevada USA. Sites were fertilized with a NO3-NH4 mix at 0, 7, and 15 kg ha-1 yr-1 from March 2012 to March 2013. In March 2013, biocrust (0-0.5 cm and bulk soils (0-10 cm were collected beneath Ambrosia canopies and in the interspaces between plants. Biomass responses were assessed as bacterial and fungal SSU rRNA gene copy number and chlorophyll a concentration. Metabolic responses were measured by five ecoenzyme activities (EEA and rates of N transformation. By most measures, nutrient availability, microbial biomass and process rates were greater in soils beneath the shrub canopy compared to the interspace between plants, and greater in the surface biocrust horizon compared to the deeper 10 cm soil profile. Most measures responded positively to experimental N addition. Effect sizes were generally greater for bulk soil than biocrust. Results were incorporated into a meta-analysis of arid ecosystem responses to N.

  4. Inorganic nitrogen addition in a semi-intensive turbot larval aquaculture system

    DEFF Research Database (Denmark)

    Blanda, Elisa; Hansen, Benni Winding; Højgaard, Jacob Kring

    2016-01-01

    A nitrogen manipulation experiment was conducted in a semi-intensive outdoor system where turbot larvae feed on copepods. Nitrogen addition is hypothesized to stimulate a cascade reaction increasing phytoplankton biomass, copepods’ productivity and larval fish survival. Triplicates were establish...... and dinoflagellate blooms had a negative effect on larval fish survival, suggesting management improvements on water quality and separation between copepods and fish production tanks.......A nitrogen manipulation experiment was conducted in a semi-intensive outdoor system where turbot larvae feed on copepods. Nitrogen addition is hypothesized to stimulate a cascade reaction increasing phytoplankton biomass, copepods’ productivity and larval fish survival. Triplicates were established...... for three treatments: a control with no additional nitrogen, a pulsed dose where nitrogen was added in three doses over time and a full dose where all nitrogen, equal to the total of the pulse dose treatment, was added initially. In the control, chlorophyll a averaged 3.3 ± 1.5 μg L−1 and phytoplankton...

  5. Nitrogen cycling in a forest stream determined by a 15N tracer addition

    Science.gov (United States)

    Patrick J. Mullholland; Jennifer L. Tank; Diane M. Sanzone; Wilfred M. Wollheim; Bruce J. Peterson; Jackson R. Webster; Judy L. Meyer

    2000-01-01

    Nitrogen uptake and cycling was examined using a six-week tracer addition of 15N-labeled ammonium in early spring in Waer Branch, a first-order deciduous forest stream in eastern Tennessee. Prior to the 15N addition, standing stocks of N were determined for the major biomass compartments. During and after the addition,

  6. Nitrogen saturation in humid tropical forests after 6 years of nitrogen and phosphorus addition

    DEFF Research Database (Denmark)

    Chen, Hao; Gurmesa, Geshere A.; Zhang, Wei

    2016-01-01

    O emission rate and nitrate (NO3-) leaching rate were measured in an N-saturated old-growth tropical forest in southern China, after 6 years of N and P addition. We hypothesized that N addition would stimulate further N saturation, but P addition might alleviate N saturation. As expected, our...

  7. Effects of nitrogen and water addition on trace element stoichiometry in five grassland species.

    Science.gov (United States)

    Cai, Jiangping; Weiner, Jacob; Wang, Ruzhen; Luo, Wentao; Zhang, Yongyong; Liu, Heyong; Xu, Zhuwen; Li, Hui; Zhang, Yuge; Jiang, Yong

    2017-07-01

    A 9-year manipulative experiment with nitrogen (N) and water addition, simulating increasing N deposition and changing precipitation regime, was conducted to investigate the bioavailability of trace elements, iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in soil, and their uptake by plants under the two environmental change factors in a semi-arid grassland of Inner Mongolia. We measured concentrations of trace elements in soil and in foliage of five common herbaceous species including 3 forbs and 2 grasses. In addition, bioaccumulation factors (BAF, the ratio of the chemical concentration in the organism and the chemical concentration in the growth substrate) and foliar Fe:Mn ratio in each plant was calculated. Our results showed that soil available Fe, Mn and Cu concentrations increased under N addition and were negatively correlated with both soil pH and cation exchange capacity. Water addition partly counteracted the positive effects of N addition on available trace element concentrations in the soil. Foliar Mn, Cu and Zn concentrations increased but Fe concentration decreased with N addition, resulting in foliar elemental imbalances among Fe and other selected trace elements. Water addition alleviated the effect of N addition. Forbs are more likely to suffer from Mn toxicity and Fe deficiency than grass species, indicating more sensitivity to changing elemental bioavailability in soil. Our results suggested that soil acidification due to N deposition may accelerate trace element cycling and lead to elemental imbalance in soil-plant systems of semi-arid grasslands and these impacts of N deposition on semi-arid grasslands were affected by water addition. These findings indicate an important role for soil trace elements in maintaining ecosystem functions associated with atmospheric N deposition and changing precipitation regimes in the future.

  8. Additional nitrogen fertilization at heading time of rice down-regulates cellulose synthesis in seed endosperm.

    Directory of Open Access Journals (Sweden)

    Keiko Midorikawa

    Full Text Available The balance between carbon and nitrogen is a key determinant of seed storage components, and thus, is of great importance to rice and other seed-based food crops. To clarify the influence of the rhizosphere carbon/nitrogen balance during the maturation stage of several seed components, transcriptome analysis was performed on the seeds from rice plants that were provided additional nitrogen fertilization at heading time. As a result, it was assessed that genes associated with molecular processes such as photosynthesis, trehalose metabolism, carbon fixation, amino acid metabolism, and cell wall metabolism were differentially expressed. Moreover, cellulose and sucrose synthases, which are involved in cellulose synthesis, were down-regulated. Therefore, we compared cellulose content of mature seeds that were treated with additional nitrogen fertilization with those from control plants using calcofluor staining. In these experiments, cellulose content in endosperm from plants receiving additional nitrogen fertilization was less than that in control endosperm. Other starch synthesis-related genes such as starch synthase 1, starch phosphorylase 2, and branching enzyme 3 were also down-regulated, whereas some α-amylase and β-amylase genes were up-regulated. On the other hand, mRNA expression of amino acid biosynthesis-related molecules was up-regulated. Moreover, additional nitrogen fertilization caused accumulation of storage proteins and up-regulated Cys-poor prolamin mRNA expression. These data suggest that additional nitrogen fertilization at heading time changes the expression of some storage substance-related genes and reduces cellulose levels in endosperm.

  9. Additional nitrogen fertilization at heading time of rice down-regulates cellulose synthesis in seed endosperm.

    Science.gov (United States)

    Midorikawa, Keiko; Kuroda, Masaharu; Terauchi, Kaede; Hoshi, Masako; Ikenaga, Sachiko; Ishimaru, Yoshiro; Abe, Keiko; Asakura, Tomiko

    2014-01-01

    The balance between carbon and nitrogen is a key determinant of seed storage components, and thus, is of great importance to rice and other seed-based food crops. To clarify the influence of the rhizosphere carbon/nitrogen balance during the maturation stage of several seed components, transcriptome analysis was performed on the seeds from rice plants that were provided additional nitrogen fertilization at heading time. As a result, it was assessed that genes associated with molecular processes such as photosynthesis, trehalose metabolism, carbon fixation, amino acid metabolism, and cell wall metabolism were differentially expressed. Moreover, cellulose and sucrose synthases, which are involved in cellulose synthesis, were down-regulated. Therefore, we compared cellulose content of mature seeds that were treated with additional nitrogen fertilization with those from control plants using calcofluor staining. In these experiments, cellulose content in endosperm from plants receiving additional nitrogen fertilization was less than that in control endosperm. Other starch synthesis-related genes such as starch synthase 1, starch phosphorylase 2, and branching enzyme 3 were also down-regulated, whereas some α-amylase and β-amylase genes were up-regulated. On the other hand, mRNA expression of amino acid biosynthesis-related molecules was up-regulated. Moreover, additional nitrogen fertilization caused accumulation of storage proteins and up-regulated Cys-poor prolamin mRNA expression. These data suggest that additional nitrogen fertilization at heading time changes the expression of some storage substance-related genes and reduces cellulose levels in endosperm.

  10. Effect of phosphate additive on the nitrogen transformation during pig manure composting.

    Science.gov (United States)

    Wu, Juan; He, Shengzhou; Liang, Ying; Li, Guoxue; Li, Song; Chen, Shili; Nadeem, Faisal; Hu, Jingwei

    2017-07-01

    Previous studies revealed that phosphate, as an additive to composting, could significantly reduce NH 3 emission and nitrogen loss through change of pH and nitrogen fixation to form ammonium phosphate. However, few studies have explored the influence of pH change and phosphate additive on NO x - -N, NH 4 + -N, NH 3 , and N 2 O, which are dominate forms of nitrogen in composting. In this study, the equimolar H 3 PO 4 , H 2 SO 4 , and K 2 HPO 4 were added into pig manure composting to evaluate the effect of H + and PO 4 3- on nitrogen transformation. As a result, we reached the conclusion that pH displays significant influence on adsorption from PO 4 3- to NH 4 + . The NH 4 + -N concentration in H 3 PO 4 treatment kept over 3 g kg -1 DM (dry matter) which is obviously higher than that in H 2 SO 4 treatment, and NH 4 + -N concentration in K 2 HPO 4 treatment (pH>8.5) is lower than 0.5 g kg -1 DM because adsorption capacity of PO 4 3- is greatly weakened and NH 4 + -N rapidly transformed to NH 3 -N influenced by high pH value. The N 2 O emission of composting is significantly correlated with incomplete denitrification of NO x - -N, and PO 4 3- addition could raise NO x - -N contents to restrict denitrification and further to promote N 2 O emission. The study reveals the influence mechanism of phosphate additive to nitrogen transformation during composting, presents theoretical basis for additive selection in nitrogen fixation, and lays foundation for study about nitrogen circulation mechanism during composting.

  11. Controlled Carbon Source Addition to an Alternating Nitrification-Denitrification Wastewater Treatment Process Including Biological P Removal

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens

    1995-01-01

    The paper investigates the effect of adding an external carbon source on the rate of denitrification in an alternating activated sludge process including biological P removal. Two carbon sources were examined, acetate and hydrolysate derived from biologically hydrolyzed sludge. Preliminary batch...... experiments performed in 5 liter bottles indicated that the denitrification rate can be instantaneously increased through the addition of either carbon source. The amount by which the rate was increased depended on the amount of carbon added. In the main experiments performed in a pilot scale alternating...... process, the addition of either carbon source to the anoxic zone also resulted in an instantaneous and fairly reproducible increase in the denitrification rate. Some release of phosphate associated with the carbon source addition was observed. With respect to nitrogen removal, these results indicate...

  12. Litter Decomposition in a Semiarid Dune Grassland: Neutral Effect of Water Supply and Inhibitory Effect of Nitrogen Addition.

    Directory of Open Access Journals (Sweden)

    Yulin Li

    Full Text Available The decomposition of plant material in arid ecosystems is considered to be substantially controlled by water and N availability. The responses of litter decomposition to external N and water, however, remain controversial, and the interactive effects of supplementary N and water also have been largely unexamined.A 3.5-year field experiment with supplementary nitrogen and water was conducted to assess the effects of N and water addition on mass loss and nitrogen release in leaves and fine roots of three dominant plant species (i.e., Artemisia halondendron, Setaria viridis, and Phragmites australis with contrasting substrate chemistry (e.g. N concentration, lignin content in this study in a desertified dune grassland of Inner Mongolia, China. The treatments included N addition, water addition, combination of N and water, and an untreated control. The decomposition rate in both leaves and roots was related to the initial litter N and lignin concentrations of the three species. However, litter quality did not explain the slower mass loss in roots than in leaves in the present study, and thus warrant further research. Nitrogen addition, either alone or in combination with water, significantly inhibited dry mass loss and N release in the leaves and roots of the three species, whereas water input had little effect on the decomposition of leaf litter and fine roots, suggesting that there was no interactive effect of supplementary N and water on litter decomposition in this system. Furthermore, our results clearly indicate that the inhibitory effects of external N on dry mass loss and nitrogen release are relatively strong in high-lignin litter compared with low-lignin litter.These findings suggest that increasing precipitation hardly facilitates ecosystem carbon turnover but atmospheric N deposition can enhance carbon sequestration and nitrogen retention in desertified dune grasslands of northern China. Additionally, litter quality of plant species

  13. Sediment diatom species and community response to nitrogen addition in Oregon (USA) estuarine tidal wetlands

    Science.gov (United States)

    Sediment microalgae play an important role in nutrient cycling and are important primary producers in the food web in Pacific Northwest estuaries. This study examines the effects of nitrogen addition to benthic microalgae in tidal wetlands of Yaquina Bay estuary on the Oregon c...

  14. Effects of fire and nitrogen addition on forage quality of Aristida purpurea

    Science.gov (United States)

    Purple threeawn (Aristida purpurea Nutt.) is a native perennial bunchgrass with limited forage value that dominates sites with disturbed soils and persists with continued severe grazing. Fire and nitrogen addition have been used to reduce threeawn and may increase grazing utilization of threeawn by...

  15. Long-term nitrogen additions and the intrinsic water-use efficiency of boreal Scots pine.

    Science.gov (United States)

    Marshall, John; Wallin, Göran; Linder, Sune; Lundmark, Tomas; Näsholm, Torgny

    2015-04-01

    Nitrogen fertilization nearly always increases productivity in boreal forests, at least in terms of wood production, but it is unclear how. In a mature (80 yrs. old) Scots pine forest in northern Sweden, we tested the extent to which nitrogen fertilization increased intrinsic photosynthetic water-use efficiency. We measured δ13C both discretely, in biweekly phloem sampling, and continuously, by monitoring of bole respiration. The original experiment was designed as a test of eddy covariance methods and is not therefore strictly replicated. Nonetheless, we compared phloem contents among fifteen trees from each plot and stem respiration from four per plot. The treatments included addition of 100 kg N/ha for eight years and a control. Phloem contents have the advantage of integrating over the whole canopy and undergoing complete and rapid turnover. Their disadvantage is that some have observed isotopic drift with transport down the length of the stem, presumably as a result of preferential export and/or reloading. We also measured the isotopic composition of stem respiration from four trees on each plot using a Picarro G1101-I CRDS attached to the vent flow from a continuous gas-exchange system. We detected consistent differences in δ13C between the treatments in phloem contents. Within each treatment, the phloem δ13C was negatively correlated with antecedent temperature (R2= 0.65) and no other measured climate variable. The isotopic composition of stem CO2 efflux will be compared to that of phloem contents. However, when converted to intrinsic water-use efficiency, the increase amounted to only about 4%. This is a small relative to the near doubling in wood production. Although we were able to detect a clear and consistent increase in water-use efficiency with N-fertilization, it constitutes but a minor cause of the observed increase in wood production.

  16. Effects of Increased Summer Precipitation and Nitrogen Addition on Root Decomposition in a Temperate Desert.

    Directory of Open Access Journals (Sweden)

    Hongmei Zhao

    Full Text Available Climate change scenarios that include precipitation shifts and nitrogen (N deposition are impacting carbon (C budgets in arid ecosystems. Roots constitute an important part of the C cycle, but it is still unclear which factors control root mass loss and nutrient release in arid lands.Litterbags were used to investigate the decomposition rate and nutrient dynamics in root litter with water and N-addition treatments in the Gurbantunggut Desert in China. Water and N addition had no significant effect on root mass loss and the N and phosphorus content of litter residue. The loss of root litter and nutrient releases were strongly controlled by the initial lignin content and the lignin:N ratio, as evidenced by the negative correlations between decomposition rate and litter lignin content and the lignin:N ratio. Fine roots of Seriphidium santolinum (with higher initial lignin content had a slower decomposition rate in comparison to coarse roots.Results from this study indicate that small and temporary changes in rainfall and N deposition do not affect root decomposition patterns in the Gurbantunggut Desert. Root decomposition rates were significantly different between species, and also between fine and coarse roots, and were determined by carbon components, especially lignin content, suggesting that root litter quality may be the primary driver of belowground carbon turnover.

  17. Nitrogen balancing and xylose addition enhances growth capacity and protein content in Chlorella minutissima cultures.

    Science.gov (United States)

    Freitas, B C B; Esquível, M G; Matos, R G; Arraiano, C M; Morais, M G; Costa, J A V

    2016-10-01

    This study aimed to examine the metabolic changes in Chlorella minutissima cells grown under nitrogen-deficient conditions and with the addition of xylose. The cell density, maximum photochemical efficiency, and chlorophyll and lipid levels were measured. The expression of two photosynthetic proteins, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and the beta subunit (AtpB) of adenosine triphosphate synthase, were measured. Comparison of cells grown in medium with a 50% reduction in the nitrogen concentration versus the traditional medium solution revealed that the cells grown under nitrogen-deficient conditions exhibited an increased growth rate, higher maximum cell density (12.7×10(6)cellsmL(-1)), optimal PSII efficiency (0.69) and decreased lipid level (25.08%). This study has taken the first steps toward protein detection in Chlorella minutissima, and the results can be used to optimize the culturing of other microalgae. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Mechanisms and modeling of the effects of additives on the nitrogen oxides emission

    Science.gov (United States)

    Kundu, Krishna P.; Nguyen, H. Lee; Kang, M. Paul

    1991-01-01

    A theoretical study on the emission of the oxides of nitrogen in the combustion of hydrocarbons is presented. The current understanding of the mechanisms and the rate parameters for gas phase reactions were used to calculate the NO(x) emission. The possible effects of different chemical species on thermal NO(x), on a long time scale were discussed. The mixing of these additives at various stages of combustion were considered and NO(x) concentrations were calculated; effects of temperatures were also considered. The chemicals such as hydrocarbons, H2, CH3OH, NH3, and other nitrogen species were chosen as additives in this discussion. Results of these calculations can be used to evaluate the effects of these additives on the NO(x) emission in the industrial combustion system.

  19. Autotrophic nitrogen removal from black water: Calcium addition as a requirement for settleability

    NARCIS (Netherlands)

    Graaff, de M.S.; Temmink, B.G.; Zeeman, G.; Loosdrecht, M.C.M.; Buisman, C.J.N.

    2011-01-01

    Black (toilet) water contains half of the organic load in the domestic wastewater, as well as the major fraction of the nutrients nitrogen and phosphorus. When collected with vacuum toilets, the black water is 25 times more concentrated than the total domestic wastewater stream, i.e. including grey

  20. Earthworm additions affect leachate production and nitrogen losses in typical midwestern agroecosystems.

    Science.gov (United States)

    Shuster, William D; Shipitalo, Martin J; Subler, Scott; Aref, Susanne; McCoy, Edward L; McKeegan, Christina

    2003-01-01

    Earthworms affect soil structure and the movement of agrochemicals. Yet, there have been few field-scale studies that quantify the effect of earthworms on dissolved nitrogen fluxes in agroecosystems. We investigated the influence of semi-annual earthworm additions on leachate production and quality in different row crop agroecosystems. Chisel-till corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation (CT) and ridge-till corn-soybean-wheat (Triticum aestivum L.) rotation (RT) plots were arranged in a complete randomized block design (n = 3) with earthworm treatments (addition and ambient) as subplots where zero-tension lysimeters were placed 45 cm below ground. We assessed earthworm populations semi-annually and collected leachate biweekly over a three-year period and determined leachate volume and concentrations of total inorganic nitrogen (TIN) and dissolved organic nitrogen (DON). Abundance of deep-burrowing earthworms was increased in addition treatments over ambient and for both agroecosystems. Leachate loss was similar among agroecosystems, but earthworm additions increased leachate production in the range of 4.5 to 45.2% above ambient in CT cropping. Although leachate TIN and DON concentrations were generally similar between agroecosystems or earthworm treatments, transport of TIN was significantly increased in addition treatments over ambient in CT cropping due to increased leachate volume. Losses of total nitrogen in leachate loadings were up to approximately 10% of agroecosystem N inputs. The coincidence of (i) soluble N production and availability and (ii) preferential leaching pathways formed by deep-burrowing earthworms thereby increased N losses from the CT agroecosystem at the 45-cm depth. Processing of N compounds and transport in soil water from RT cropping were more affected by management phase and largely independent of earthworm activity.

  1. The effects of warming and nitrogen addition on soil nitrogen cycling in a temperate grassland, northeastern China.

    Directory of Open Access Journals (Sweden)

    Lin-Na Ma

    Full Text Available Both climate warming and atmospheric nitrogen (N deposition are predicted to affect soil N cycling in terrestrial biomes over the next century. However, the interactive effects of warming and N deposition on soil N mineralization in temperate grasslands are poorly understood.A field manipulation experiment was conducted to examine the effects of warming and N addition on soil N cycling in a temperate grassland of northeastern China from 2007 to 2009. Soil samples were incubated at a constant temperature and moisture, from samples collected in the field. The results showed that both warming and N addition significantly stimulated soil net N mineralization rate and net nitrification rate. Combined warming and N addition caused an interactive effect on N mineralization, which could be explained by the relative shift of soil microbial community structure because of fungal biomass increase and strong plant uptake of added N due to warming. Irrespective of strong intra- and inter-annual variations in soil N mineralization, the responses of N mineralization to warming and N addition did not change during the three growing seasons, suggesting independence of warming and N responses of N mineralization from precipitation variations in the temperate grassland.Interactions between climate warming and N deposition on soil N cycling were significant. These findings will improve our understanding on the response of soil N cycling to the simultaneous climate change drivers in temperate grassland ecosystem.

  2. The influence of sterilization on nitrogen-included ultrananocrystalline diamond for biomedical applications

    International Nuclear Information System (INIS)

    Tong, Wei; Tran, Phong A.; Turnley, Ann M.; Aramesh, Morteza; Prawer, Steven; Brandt, Milan; Fox, Kate

    2016-01-01

    Diamond has shown great potential in different biomedical applications, but the effects of sterilization on its properties have not been investigated. Here, we studied the influence of five sterilization techniques (solvent cleaning, oxygen plasma, UV irradiation, autoclave and hydrogen peroxide) on nitrogen-included ultrananocrystalline diamond. The chemical modification of the diamond surface was evaluated using X-ray photoelectron spectroscopy and water contact angle measurements. Different degrees of surface oxidation and selective sp 2 bonded carbon etching were found following all sterilization techniques, resulting in an increase of hydrophilicity. Higher viabilities of in vitro mouse 3T3 fibroblasts and rat cortical neuron cells were observed on oxygen plasma, autoclave and hydrogen peroxide sterilized diamond, which correlated with their higher hydrophilicity. By examination of apatite formation in simulated body fluid, in vivo bioactivity was predicted to be best on those surfaces which have been oxygen plasma treated and lowest on those which have been exposed to UV irradiation. The charge injection properties were also altered by the sterilization process and there appears to be a correlation between these changes and the degree of oxygen termination of the surface. We find that the modification brought by autoclave, oxygen plasma and hydrogen peroxide were most consistent with the use of N-UNCD in biological applications as compared to samples sterilized by solvent cleaning or UV exposure or indeed non-sterilized. A two-step process of sterilization by hydrogen peroxide following oxygen plasma treatment was then suggested. However, the final choice of sterilization technique will depend on the intended end application. - Highlights: • We test for the first time the effect of 5 sterilization techniques on nitrogen included ultrananocrystalline diamond. • Different degrees of surface oxidation and selective sp 2 bonded carbon etching were found to

  3. The influence of sterilization on nitrogen-included ultrananocrystalline diamond for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Wei [School of Physics, University of Melbourne, Parkville, Victoria (Australia); Tran, Phong A. [Department of Chemical and Biomolecular Engineering, University of Melbourne, Parkville, Victoria (Australia); Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland (Australia); Turnley, Ann M. [Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria (Australia); Aramesh, Morteza [School of Physics, University of Melbourne, Parkville, Victoria (Australia); School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland (Australia); Prawer, Steven [School of Physics, University of Melbourne, Parkville, Victoria (Australia); Brandt, Milan [Centre for Additive Manufacturing, School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Victoria (Australia); Fox, Kate, E-mail: kate.fox@rmit.edu.au [Centre for Additive Manufacturing, School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Melbourne, Victoria (Australia)

    2016-04-01

    Diamond has shown great potential in different biomedical applications, but the effects of sterilization on its properties have not been investigated. Here, we studied the influence of five sterilization techniques (solvent cleaning, oxygen plasma, UV irradiation, autoclave and hydrogen peroxide) on nitrogen-included ultrananocrystalline diamond. The chemical modification of the diamond surface was evaluated using X-ray photoelectron spectroscopy and water contact angle measurements. Different degrees of surface oxidation and selective sp{sup 2} bonded carbon etching were found following all sterilization techniques, resulting in an increase of hydrophilicity. Higher viabilities of in vitro mouse 3T3 fibroblasts and rat cortical neuron cells were observed on oxygen plasma, autoclave and hydrogen peroxide sterilized diamond, which correlated with their higher hydrophilicity. By examination of apatite formation in simulated body fluid, in vivo bioactivity was predicted to be best on those surfaces which have been oxygen plasma treated and lowest on those which have been exposed to UV irradiation. The charge injection properties were also altered by the sterilization process and there appears to be a correlation between these changes and the degree of oxygen termination of the surface. We find that the modification brought by autoclave, oxygen plasma and hydrogen peroxide were most consistent with the use of N-UNCD in biological applications as compared to samples sterilized by solvent cleaning or UV exposure or indeed non-sterilized. A two-step process of sterilization by hydrogen peroxide following oxygen plasma treatment was then suggested. However, the final choice of sterilization technique will depend on the intended end application. - Highlights: • We test for the first time the effect of 5 sterilization techniques on nitrogen included ultrananocrystalline diamond. • Different degrees of surface oxidation and selective sp{sup 2} bonded carbon etching were

  4. Effect of nitrogen addition on the structural, electrical, and optical properties of In-Sn-Zn oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Junjun, E-mail: jia@chem.aoyama.ac.jp [Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258 (Japan); Torigoshi, Yoshifumi; Suko, Ayaka; Nakamura, Shin-ichi [Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258 (Japan); Kawashima, Emi; Utsuno, Futoshi [Advanced Technology Research Laboratories, Idemitsu Kosan Co., Ltd., Sodegaura, Chiba 299-0293 (Japan); Shigesato, Yuzo, E-mail: yuzo@chem.aoyama.ac.jp [Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258 (Japan)

    2017-02-28

    Highlights: • Nitrogen addition induces the structure of ITZO film change from amorphous phase to a c-axis oriented InN polycrystalline phase. • Nitrogen addition suppressed the formation of oxygen-related vacancies in ITZO films. • A red-shift in the optical band edge for ITZO films was observed as the nitrogen flow ratio increased, which was due to the generation of InN crystallites. - Abstract: Indium-tin-zinc oxide (ITZO) films were deposited at various nitrogen flow ratios using magnetron sputtering. At a nitrogen flow ratio of 40%, the structure of ITZO film changed from amorphous, with a short-range-ordered In{sub 2}O{sub 3} phase, to a c-axis oriented InN polycrystalline phase, where InN starts to nucleate from an amorphous In{sub 2}O{sub 3} matrix. Whereas, nitrogen addition had no obvious effect on the structure of indium-gallium-zinc oxide (IGZO) films even at a nitrogen flow ratio of 100%. Nitrogen addition also suppressed the formation of oxygen-related vacancies in ITZO films when the nitrogen flow ratio was less than 20%, and higher nitrogen addition led to an increase in carrier density. Moreover, a red-shift in the optical band edge was observed as the nitrogen flow ratio increased, which could be attributed to the generation of InN crystallites. We anticipate that the present findings demonstrating nitrogen-addition induced structural changes can help to understand the environment-dependent instability in amorphous IGZO or ITZO based thin-film transistors (TFTs).

  5. Delayed addition of nitrogen-rich substrates during composting of municipal waste: Effects on nitrogen loss, greenhouse gas emissions and compost stability.

    Science.gov (United States)

    Nigussie, Abebe; Bruun, Sander; Kuyper, Thomas W; de Neergaard, Andreas

    2017-01-01

    Municipal waste is usually composted with an N-rich substrate, such as manure, to increase the N content of the product. This means that a significant amount of nitrogen can be lost during composting. The objectives of this study were (i) to investigate the effect of split addition of a nitrogen-rich substrate (poultry manure) on nitrogen losses and greenhouse gas emissions during composting and to link this effect to different bulking agents (coffee husks and sawdust), and (ii) to assess the effect of split addition of a nitrogen-rich substrate on compost stability and sanitisation. The results showed that split addition of the nitrogen-rich substrate reduced nitrogen losses by 9% when sawdust was used and 20% when coffee husks were used as the bulking agent. Depending on the bulking agent used, split addition increased cumulative N 2 O emissions by 400-600% compared to single addition. In contrast, single addition increased methane emissions by up to 50% compared to split addition of the substrate. Hence, the timing of the addition of the N-rich substrate had only a marginal effect on total non-CO 2 greenhouse gas emissions. Split addition of the N-rich substrate resulted in compost that was just as stable and effective at completely eradicating weed seeds as single addition. These findings therefore show that split addition of a nitrogen-rich substrate could be an option for increasing the fertilising value of municipal waste compost without having a significant effect on total greenhouse gas emissions or compost stability. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. The effect of nitrogen addition on the fermentative performance during sparkling wine production

    OpenAIRE

    Martí-Raga, M.; Sancho, M.; Guillamón, J.M.; Mas, A.; Beltran, G.

    2015-01-01

    10.1016/j.foodres.2014.10.033 The transformation of must to wine is influenced by several factors, including the nitrogen composition of the grape must, which has an important impact on yeast growth, fermentation kinetics and the organoleptic properties of the final product. In the production of sparkling wine by the traditional method, a second fermentation takes place inside the bottle, followed by yeast autolysis. Before their inoculation, yeasts cells must be adapted to the wine by th...

  7. Effect of nitrogen addition on the structural, electrical, and optical properties of In-Sn-Zn oxide thin films

    Science.gov (United States)

    Jia, Junjun; Torigoshi, Yoshifumi; Suko, Ayaka; Nakamura, Shin-ichi; Kawashima, Emi; Utsuno, Futoshi; Shigesato, Yuzo

    2017-02-01

    Indium-tin-zinc oxide (ITZO) films were deposited at various nitrogen flow ratios using magnetron sputtering. At a nitrogen flow ratio of 40%, the structure of ITZO film changed from amorphous, with a short-range-ordered In2O3 phase, to a c-axis oriented InN polycrystalline phase, where InN starts to nucleate from an amorphous In2O3 matrix. Whereas, nitrogen addition had no obvious effect on the structure of indium-gallium-zinc oxide (IGZO) films even at a nitrogen flow ratio of 100%. Nitrogen addition also suppressed the formation of oxygen-related vacancies in ITZO films when the nitrogen flow ratio was less than 20%, and higher nitrogen addition led to an increase in carrier density. Moreover, a red-shift in the optical band edge was observed as the nitrogen flow ratio increased, which could be attributed to the generation of InN crystallites. We anticipate that the present findings demonstrating nitrogen-addition induced structural changes can help to understand the environment-dependent instability in amorphous IGZO or ITZO based thin-film transistors (TFTs).

  8. Resource Availability Drives Responses of Soil Microbial Communities to Short-term Precipitation and Nitrogen Addition in a Desert Shrubland

    Directory of Open Access Journals (Sweden)

    Weiwei She

    2018-02-01

    Full Text Available Desert microbes are expected to be substantially sensitive to global environmental changes, such as precipitation changes and elevated nitrogen deposition. However, the effects of precipitation changes and nitrogen enrichment on their diversity and community composition remain poorly understood. We conducted a field experiment over 2 years with multi-level precipitation and nitrogen addition in a desert shrubland of northern China, to examine the responses of soil bacteria and fungi in terms of diversity and community composition and to explore the roles of plant and soil factors in structuring microbial communities. Water addition significantly increased soil bacterial diversity and altered the community composition by increasing the relative abundances of stress-tolerant (dormant taxa (e.g., Acidobacteria and Planctomycetes; however, nitrogen addition had no substantial effects. Increased precipitation and nitrogen did not impact soil fungal diversity, but significantly shifted the fungal community composition. Specifically, water addition reduced the relative abundances of drought-tolerant taxa (e.g., the orders Pezizales, Verrucariales, and Agaricales, whereas nitrogen enrichment decreased those of oligotrophic taxa (e.g., the orders Agaricales and Sordariales. Shifts in microbial community composition under water and nitrogen addition occurred primarily through changing resource availability rather than plant community. Our results suggest that water and nitrogen addition affected desert microbes in different ways, with watering shifting stress-tolerant traits and fertilization altering copiotrophic/oligotrophic traits of the microbial communities. These findings highlight the importance of resource availability in driving the desert microbial responses to short-term environmental changes.

  9. The influence of sterilization on nitrogen-included ultrananocrystalline diamond for biomedical applications.

    Science.gov (United States)

    Tong, Wei; Tran, Phong A; Turnley, Ann M; Aramesh, Morteza; Prawer, Steven; Brandt, Milan; Fox, Kate

    2016-04-01

    Diamond has shown great potential in different biomedical applications, but the effects of sterilization on its properties have not been investigated. Here, we studied the influence of five sterilization techniques (solvent cleaning, oxygen plasma, UV irradiation, autoclave and hydrogen peroxide) on nitrogen-included ultrananocrystalline diamond. The chemical modification of the diamond surface was evaluated using X-ray photoelectron spectroscopy and water contact angle measurements. Different degrees of surface oxidation and selective sp(2) bonded carbon etching were found following all sterilization techniques, resulting in an increase of hydrophilicity. Higher viabilities of in vitro mouse 3T3 fibroblasts and rat cortical neuron cells were observed on oxygen plasma, autoclave and hydrogen peroxide sterilized diamond, which correlated with their higher hydrophilicity. By examination of apatite formation in simulated body fluid, in vivo bioactivity was predicted to be best on those surfaces which have been oxygen plasma treated and lowest on those which have been exposed to UV irradiation. The charge injection properties were also altered by the sterilization process and there appears to be a correlation between these changes and the degree of oxygen termination of the surface. We find that the modification brought by autoclave, oxygen plasma and hydrogen peroxide were most consistent with the use of N-UNCD in biological applications as compared to samples sterilized by solvent cleaning or UV exposure or indeed non-sterilized. A two-step process of sterilization by hydrogen peroxide following oxygen plasma treatment was then suggested. However, the final choice of sterilization technique will depend on the intended end application. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Nutrient additions in pristine Patagonian Sphagnum bog vegetation : can phosphorus addition alleviate (the effects of) increased nitrogen loads

    NARCIS (Netherlands)

    Fritz, C.; Dijk, G. van; Smolders, A.J.P.; Pancotto, V.A.; Elzenga, J.T.M.; Roelofs, J.G.M.; Grootjans, A.P.

    Sphagnum-bog ecosystems have a limited capability to retain carbon and nutrients when subjected to increased nitrogen (N) deposition. Although it has been proposed that phosphorus (P) can dilute negative effects of nitrogen by increasing biomass production of Sphagnum mosses, it is still unclear

  11. Effects of nitrogen and water addition on trace element stoichiometry in five grassland species

    DEFF Research Database (Denmark)

    Cai, Jiangping; Weiner, Jacob; Wang, Ruzhen

    2017-01-01

    A 9-year manipulative experiment with nitrogen (N) and water addition, simulating increasing N deposition and changing precipitation regime, was conducted to investigate the bioavailability of trace elements, iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in soil, and their uptake by plants...... alleviated the effect of N addition. Forbs are more likely to suffer from Mn toxicity and Fe deficiency than grass species, indicating more sensitivity to changing elemental bioavailability in soil. Our results suggested that soil acidification due to N deposition may accelerate trace element cycling...... and lead to elemental imbalance in soil–plant systems of semi-arid grasslands and these impacts of N deposition on semi-arid grasslands were affected by water addition. These findings indicate an important role for soil trace elements in maintaining ecosystem functions associated with atmospheric N...

  12. Nitrogen addition alters elemental stoichiometry within soil aggregates in a temperate steppe

    Science.gov (United States)

    Yin, Jinfei; Wang, Ruzhen; Liu, Heyong; Feng, Xue; Xu, Zhuwen; Jiang, Yong

    2016-11-01

    Ongoing increases in anthropogenic nitrogen (N) inputs have largely affected soil carbon (C) and nutrient cycling in most terrestrial ecosystems. Numerous studies have concerned the effects of elevated N inputs on soil dissolved organic carbon (DOC), dissolved inorganic N (DIN), available phosphorus (AP), exchangeable calcium (Ca) and magnesium (Mg), and available iron (Fe) and manganese (Mn). However, few have emphasized the stoichiometric traits of these soil parameters, especially within different soil aggregate fractions. In a semiarid grassland of Inner Mongolia, we studied the effect of N addition on the ratios of DOC : DIN, DOC : AP, DIN : AP, exchangeable Ca : Mg, available Fe : Mn within three soil aggregate classes of large macroaggregates (> 2000 µm), small macroaggregates (250-2000 µm), and microaggregates (soil aggregates. The soil DOC : AP ratio significantly decreased along with increasing N gradients within large macroaggregates and microaggregates. Nitrogen significantly decreased the ratio of exchangeable Ca : Mg within soil macroaggregates. The ratio of available Fe : Mn decreased with N addition within three soil aggregate classes. Alteration of elemental stoichiometry within soil fractions that are characterized by different nutrient retention capacity will influence the chemical composition of soil microorganisms and plant quality.

  13. Nematodes, exotic earthworms and nitrogen addition: interactions between global change factors lead to cancellation effects.

    Science.gov (United States)

    De Long, Jonathan R

    2017-07-01

    Photos from the experiment described in Shao et al. (): (a) the endogeic (i.e. earthworms that typically live in the soil, burrowing horizontally to acquire nutrients) earthworm Pontoscolex corethrurus that was added to the plots; (b) P. corethrurus in a quiescence state in response to drought; (c) set-up of the control plots (i.e. no earthworms, ambient nitrogen) used in this experiment. [Colour figure can be viewed at wileyonlinelibrary.com] In Focus: Shao, Y., Zhang, W., Eisenhauer, N., Liu, T., Xiong, Y., Liang, C. & Fu, S. (2017) Nitrogen deposition cancels out exotic earthworm effects on plant-feeding nematode communities. Journal of Animal Ecology, 86, 708-717. In this issue of Journal of Animal Ecology, Shao et al. () explored how N addition and exotic earthworms interacted to impact on the plant-feeding nematode community. They demonstrate that exotic earthworm presence alone increased the abundance of less harmful plant-feeding nematodes and decreased the abundance of the more harmful plant-feeding nematodes. However, in plots receiving both exotic earthworms and N addition, such earthworm effects on the nematode community were negated. These findings pull focus on the need to simultaneously consider multiple global change factors (e.g. exotic species invasions and N deposition) when making predictions about how such factors might affect above- and below-ground interactions and thereby alter ecosystem function. © 2017 The Author. Journal of Animal Ecology © 2017 British Ecological Society.

  14. Effects of experimental nitrogen additions on plant diversity in tropical forests of contrasting disturbance regimes in southern China

    International Nuclear Information System (INIS)

    Lu Xiankai; Mo Jiangming; Gilliam, Frank S.; Yu Guirui; Zhang Wei; Fang Yunting; Huang Juan

    2011-01-01

    Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (with harvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha -1 yr -1 , and 100 kg N ha -1 yr -1 . Nitrogen additions did not significantly affect understory plant richness, density, and cover in the disturbed forest. Similarly, no significant response was found for canopy closure in this forest. In the rehabilitated forest, species richness and density showed no significant response to N additions; however, understory cover decreased significantly in the N-treated plots, largely a function of a significant increase in canopy closure. Our results suggest that responses of plant diversity to N deposition may vary with different land-use history, and rehabilitated forests may be more sensitive to N deposition. - Highlights: → Nitrogen addition had no significant effect on understory plant diversity in the disturbed forest. → Nitrogen addition significantly decreased understory plant cover. → Nitrogen addition had no effect on richness and density in the rehabilitated forest. → The decrease is largely a function of a significant increase in canopy closure. → Land-use practices may dominate the responses of plant diversity to N addition. - Research in disturbed forests of southeastern China demonstrates that land-use history can substantially alter effects of excess nitrogen deposition on plant diversity of tropical forest ecosystems.

  15. Stimulation of terrestrial ecosystem carbon storage by nitrogen addition: a meta-analysis.

    Science.gov (United States)

    Yue, Kai; Peng, Yan; Peng, Changhui; Yang, Wanqin; Peng, Xin; Wu, Fuzhong

    2016-01-27

    Elevated nitrogen (N) deposition alters the terrestrial carbon (C) cycle, which is likely to feed back to further climate change. However, how the overall terrestrial ecosystem C pools and fluxes respond to N addition remains unclear. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of C pools and fluxes to experimental N addition using a comprehensive meta-analysis method. Our results showed that N addition significantly stimulated soil total C storage by 5.82% ([2.47%, 9.27%], 95% CI, the same below) and increased the C contents of the above- and below-ground parts of plants by 25.65% [11.07%, 42.12%] and 15.93% [6.80%, 25.85%], respectively. Furthermore, N addition significantly increased aboveground net primary production by 52.38% [40.58%, 65.19%] and litterfall by 14.67% [9.24%, 20.38%] at a global scale. However, the C influx from the plant litter to the soil through litter decomposition and the efflux from the soil due to microbial respiration and soil respiration showed insignificant responses to N addition. Overall, our meta-analysis suggested that N addition will increase soil C storage and plant C in both above- and below-ground parts, indicating that terrestrial ecosystems might act to strengthen as a C sink under increasing N deposition.

  16. EVAPORATION: a new vapour pressure estimation methodfor organic molecules including non-additivity and intramolecular interactions

    Science.gov (United States)

    Compernolle, S.; Ceulemans, K.; Müller, J.-F.

    2011-09-01

    We present EVAPORATION (Estimation of VApour Pressure of ORganics, Accounting for Temperature, Intramolecular, and Non-additivity effects), a method to predict (subcooled) liquid pure compound vapour pressure p0 of organic molecules that requires only molecular structure as input. The method is applicable to zero-, mono- and polyfunctional molecules. A simple formula to describe log10p0(T) is employed, that takes into account both a wide temperature dependence and the non-additivity of functional groups. In order to match the recent data on functionalised diacids an empirical modification to the method was introduced. Contributions due to carbon skeleton, functional groups, and intramolecular interaction between groups are included. Molecules typically originating from oxidation of biogenic molecules are within the scope of this method: aldehydes, ketones, alcohols, ethers, esters, nitrates, acids, peroxides, hydroperoxides, peroxy acyl nitrates and peracids. Therefore the method is especially suited to describe compounds forming secondary organic aerosol (SOA).

  17. Effects of nitrogen and phosphorus addition on leaf nutrient characteristics in a subtropical forest

    Science.gov (United States)

    Yang, H.; Li, S.

    2017-12-01

    Increasing nitrogen (N) and phosphorus (P) deposition could influence plant growth and survival to varying extents. N and P deposition is essential for subtropical forests where plant growth is limited by lower soil P availability in highly weathered soils. However, whether N and P deposition can increase leaf P concentration and alleviate P limitation is unclear. We investigated changes in N and P concentrations, N:P ratios, and resorption for 6 dominant species (2 tree species and 4 understory species), following 2 years of N and P additions in a subtropical forest in southern China. P addition either alone or together with the addition of N increased green leaf P concentrations (except in Schima superb) and senesced leaf P and decreased N:P ratios (except in Pinus massoniana), but had no influence on P resorption. N addition had no apparent influence on leaf N concentrations, N:P ratios, or N resorption in all species. The considerable influence of P addition can be explained by rising soil P availability. Our results suggest that subtropical forests are P limited and that increasing P deposition can moderately alleviate the limitation of P. Furthermore, P deposited in conjunction with high quantities of N does not enhance P limitation, as it is insensitive to elevated N input.

  18. The effect of nitrogen additions on bracken fern and its insect herbivores at sites with high and low atmospheric pollution

    Science.gov (United States)

    M.E. Jones; M.E. Fenn; T.D. Paine

    2011-01-01

    The impact of atmospheric pollution, including nitrogen deposition, on bracken fern herbivores has never been studied. Bracken fern is globally distributed and has a high potential to accumulate nitrogen in plant tissue. We examined the response of bracken fern and its herbivores to N fertilization at a high and low pollution site in forests downwind of Los Angeles,...

  19. Nitrogen Addition Exacerbates the Negative Effects of Low Temperature Stress on Carbon and Nitrogen Metabolism in Moss

    Directory of Open Access Journals (Sweden)

    Bin-Yang Liu

    2017-08-01

    Full Text Available Global environmental changes are leading to an increase in localized abnormally low temperatures and increasing nitrogen (N deposition is a phenomenon recognized worldwide. Both low temperature stress (LTS and excess N induce oxidative stress in plants, and excess N also reduces their resistance to LTS. Mosses are primitive plants that are generally more sensitive to alterations in environmental factors than vascular species. To study the combined effects of N deposition and LTS on carbon (C and N metabolism in moss, two moss species, Pogonatum cirratum subsp. fuscatum, and Hypnum plumaeforme, exposed to various concentrations of nitrate (KNO3 or ammonium (NH4Cl, were treated with or without LTS. C/N metabolism indices were then monitored, both immediately after the stress and after a short recovery period (10 days. LTS decreased the photosystem II (PSII performance index and inhibited non-cyclic photophosphorylation, ribulose-1,5-bisphosphate carboxylase, and glutamine synthetase activities, indicating damage to PSII and reductions in C/N assimilation in these mosses. LTS did not affect cyclic photophosphorylation, sucrose synthase, sucrose-phosphate synthase, and NADP-isocitrate dehydrogenase activities, suggesting a certain level of energy and C skeleton generation were maintained in the mosses to combat LTS; however, LTS inhibited the activity of glycolate oxidase. As predicted, N supply increased the sensitivity of the mosses to LTS, resulting in greater damage to PSII and a sharper decrease in C/N assimilation. After the recovery period, the performance of PSII and C/N metabolism, which were inhibited by LTS increased significantly, and were generally higher than those of control samples not exposed to LTS, suggesting overcompensation effects; however, N application reduced the extent of compensation effects. Both C and N metabolism exhibited stronger compensation effects in H. plumaeforme than in P. cirratum subsp. fuscatum. The

  20. Individual size but not additional nitrogen regulates tree carbon sequestration in a subtropical forest

    Science.gov (United States)

    Wu, Jianping; Duan, Honglang; Liu, Wenfei; Wei, Xiaohua; Liao, Yingchun; Fan, Houbao

    2017-04-01

    Recent studies have indicated that tree carbon accumulation in subtropical forests has been negatively affected by global change phenomena such as warming and drought. However, the long-term effect of nitrogen addition on plant carbon storage remains poorly understood in these regions. In this study, we conducted a 10-year field experiment examining the effect of experimental N addition on plant growth and carbon storage in a subtropical Chinese fir forest. The N levels were 0 (control), 60, 120, and 240 kg ha-1 yr-1, and the N effects on tree carbon were divided into stand and individual levels. The results indicated that tree carbon storage at the stand scale was not affected by long-term N addition in the subtropical forest. By contrast, significant impacts of different tree size classes on carbon sequestration were found under different N treatments, which indicated that the amount of plant carbon sequestration was significantly enhanced with tree size class. Our findings highlight the importance of community structure and growth characteristics in Chinese fir forests, in which individual size but not additional N regulates tree carbon sequestration in this subtropical forest.

  1. EVAPORATION: a new vapour pressure estimation methodfor organic molecules including non-additivity and intramolecular interactions

    Directory of Open Access Journals (Sweden)

    S. Compernolle

    2011-09-01

    Full Text Available We present EVAPORATION (Estimation of VApour Pressure of ORganics, Accounting for Temperature, Intramolecular, and Non-additivity effects, a method to predict (subcooled liquid pure compound vapour pressure p0 of organic molecules that requires only molecular structure as input. The method is applicable to zero-, mono- and polyfunctional molecules. A simple formula to describe log10p0(T is employed, that takes into account both a wide temperature dependence and the non-additivity of functional groups. In order to match the recent data on functionalised diacids an empirical modification to the method was introduced. Contributions due to carbon skeleton, functional groups, and intramolecular interaction between groups are included. Molecules typically originating from oxidation of biogenic molecules are within the scope of this method: aldehydes, ketones, alcohols, ethers, esters, nitrates, acids, peroxides, hydroperoxides, peroxy acyl nitrates and peracids. Therefore the method is especially suited to describe compounds forming secondary organic aerosol (SOA.

  2. Moss-specific changes in nitrogen fixation following two decades of warming, shading, and fertilizer addition

    DEFF Research Database (Denmark)

    Sørensen, Pernille Lærkedal; Lett, Signe; Michelsen, Anders

    2012-01-01

    Climate warming will induce changes in Arctic ecosystem carbon balance, but besides climate, nitrogen availability is a critical controlling factor of carbon cycling. It is therefore essential to obtain knowledge on the influence of a changing climate on nitrogen fixation, as this process...... is the main source of new nitrogen to arctic ecosystems. In order to gain information on future nitrogen fixation rates in a changing climate, we studied the effects of two decades of warming with passive greenhouses, shading with sackcloth, and fertilization with NPK fertilizer on nitrogen fixation rates....... To expand the knowledge on species-specific responses, we measured nitrogen fixation associated with two moss species: Hylocomium splendens and Aulacomnium turgidum. Our expectations of decreased nitrogen fixation rates in the fertilizer and shading treatments were met. However, contrary to our expectation...

  3. Effects of water and nitrogen addition on species turnover in temperate grasslands in northern China.

    Directory of Open Access Journals (Sweden)

    Zhuwen Xu

    Full Text Available Global nitrogen (N deposition and climate change have been identified as two of the most important causes of current plant diversity loss. However, temporal patterns of species turnover underlying diversity changes in response to changing precipitation regimes and atmospheric N deposition have received inadequate attention. We carried out a manipulation experiment in a steppe and an old-field in North China from 2005 to 2009, to test the hypothesis that water addition enhances plant species richness through increase in the rate of species gain and decrease in the rate of species loss, while N addition has opposite effects on species changes. Our results showed that water addition increased the rate of species gain in both the steppe and the old field but decreased the rates of species loss and turnover in the old field. In contrast, N addition increased the rates of species loss and turnover in the steppe but decreased the rate of species gain in the old field. The rate of species change was greater in the old field than in the steppe. Water interacted with N to affect species richness and species turnover, indicating that the impacts of N on semi-arid grasslands were largely mediated by water availability. The temporal stability of communities was negatively correlated with rates of species loss and turnover, suggesting that water addition might enhance, but N addition would reduce the compositional stability of grasslands. Experimental results support our initial hypothesis and demonstrate that water and N availabilities differed in the effects on rate of species change in the temperate grasslands, and these effects also depend on grassland types and/or land-use history. Species gain and loss together contribute to the dynamic change of species richness in semi-arid grasslands under future climate change.

  4. Exogenous Nitrogen Addition Reduced the Temperature Sensitivity of Microbial Respiration without Altering the Microbial Community Composition

    Directory of Open Access Journals (Sweden)

    Hui Wei

    2017-12-01

    Full Text Available Atmospheric nitrogen (N deposition is changing in both load quantity and chemical composition. The load effects have been studied extensively, whereas the composition effects remain poorly understood. We conducted a microcosm experiment to study how N chemistry affected the soil microbial community composition characterized by phospholipid fatty acids (PLFAs and activity indicated by microbial CO2 release. Surface and subsurface soils collected from an old-growth subtropical forest were supplemented with three N-containing materials (ammonium, nitrate, and urea at the current regional deposition load (50 kg ha-1 yr-1 and incubated at three temperatures (10, 20, and 30°C to detect the interactive effects of N deposition and temperature. The results showed that the additions of N, regardless of form, did not alter the microbial PLFAs at any of the three temperatures. However, the addition of urea significantly stimulated soil CO2 release in the early incubation stage. Compared with the control, N addition consistently reduced the temperature dependency of microbial respiration, implying that N deposition could potentially weaken the positive feedback of the warming-stimulated soil CO2 release to the atmosphere. The consistent N effects for the surface and subsurface soils suggest that the effects of N on soil microbial communities may be independent of soil chemical contents and stoichiometry.

  5. Nitrogen Addition Changes the Stoichiometry and Growth Rate of Different Organs in Pinus tabuliformis Seedlings

    Directory of Open Access Journals (Sweden)

    Hang Jing

    2017-11-01

    Full Text Available Background: Nitrogen (N deposition could influence plant stoichiometry and growth rate and thus alter the structure and function of the ecosystem. However, the mechanism by which N deposition changes the stoichiometry and relative growth rate (RGR of plant organs, especially roots with different diameters, is unclear.Methods: We created a gradient of N availability (0–22.4 g N m-2 year-1 for Pinus tabuliformis seedlings for 3 years and examined changes in the carbon (C:N:phosphorus (P ratios and RGRs of the leaves, stems, and roots with four diameter classes (finest roots, <0.5 mm; finer roots, 0.5–1 mm; middle roots, 1–2 mm; and coarse roots, >2 mm.Results: (1 N addition significantly increased the C and N contents of the leaves and whole roots, the C content of the stems, the N:P ratios of the leaves and stems, and the C:P ratio of the whole roots. (2 In the root system, the C:N ratio of the finest roots and the C:P ratios of the finest and finer roots significantly changed with N addition. The N:P ratios of the finest, finer, and middle roots significantly increased with increasing amount of N added. The stoichiometric responses of the roots were more sensitive to N addition than those of the other organs (3 The RGR of all the organs significantly increased at low N addition levels (2.8–11.2 g N m-2 year-1 but decreased at high N addition levels (22.4 g N m-2 year-1. (4 The RGRs of the whole seedlings and leaves were not significantly correlated with their N:P ratios at low and high N addition levels. By contrast, the RGRs of the stems and roots showed a significantly positive correlation with their own N:P ratio only at low N addition level.Conclusion: Addition of N affected plant growth by altering the contents of C and N; the ratios of C, N, and P; and the RGRs of the organs. RGR is correlated with the N:P ratios of the stems and roots at low N addition level but not at high N addition level. This finding is inconsistent with the

  6. Effects of Experimental Nitrogen and Phosphorus Addition on Litter Decomposition in an Old-Growth Tropical Forest

    OpenAIRE

    Chen, Hao; Dong, Shaofeng; Liu, Lei; Ma, Chuan; Zhang, Tao; Zhu, Xiaomin; Mo, Jiangming

    2013-01-01

    The responses of litter decomposition to nitrogen (N) and phosphorus (P) additions were examined in an old-growth tropical forest in southern China to test the following hypotheses: (1) N addition would decrease litter decomposition; (2) P addition would increase litter decomposition, and (3) P addition would mitigate the inhibitive effect of N addition. Two kinds of leaf litter, Schima superba Chardn. & Champ. (S.S.) and Castanopsis chinensis Hance (C.C.), were studied using the litterbag te...

  7. Effects of phosphorus and nitrogen additions on tropical soil microbial activity in the context of experimental warming

    Science.gov (United States)

    Foley, M.; Nottingham, A.; Turner, B. L.

    2017-12-01

    Soil warming is generally predicted to increase microbial mineralization rates and accelerate soil C losses which could establish a positive feedback to climatic warming. Tropical rain forests account for a third of global soil C, yet the responseto of tropical soil C a warming climate remains poorly understood. Despite predictions of soil C losses, decomposition of soil organic matter (SOM) in tropical soils may be constrained by several factors including microbial nutrient deficiencies. We performed an incubation experiment in conjunction with an in-situ soil warming experiment in a lowland tropical forest on Barro Colorado Island, Panama, to measure microbial response to two key nutrient additions in shallow (0-10cm) and deep (50-100 cm) soils. We compared the response of lowland tropical soils to montane tropical soils, predicting that lowland soils would display the strongest response to phosphorus additions. Soils were treated with either carbon alone (C), nitrogen (CN), phosphorus (CP) or nitrogen and phosphorus combined (CNP). Carbon dioxide (CO2) production was measured by NaOH capture and titrimetric analysis for 10 days. Cumulative CO2 production in montane soils increased significantly with all additions, suggesting these soils are characterized by a general microbial nutrient deficiency. The cumulative amount of C respired in deep soils from the lowland site increased significantly with CP and CNP additions, suggesting that microbial processes in deep lowland tropical soils are phosphorus-limited. These results support the current understanding that lowland tropical forests are growing on highly weathered, phosphorus-deplete soils, and provide novel insight that deep tropical SOM may be stabilized by a lack of biologically-available phosphorus. Further, this data suggests tropical soil C losses under elevated temperature may be limited by a strong microbial phosphorus deficiency.

  8. LIFE Chamber Chemical Equilibrium Simulations with Additive Hydrogen, Oxygen, and Nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    DeMuth, J A; Simon, A J

    2009-09-03

    In order to enable continuous operation of a Laser Inertial confinement Fusion Energy (LIFE) engine, the material (fill-gas and debris) in the fusion chamber must be carefully managed. The chamber chemical equilibrium compositions for post-shot mixtures are evaluated to determine what compounds will be formed at temperatures 300-5000K. It is desired to know if carbon and or lead will deposit on the walls of the chamber, and if so: at what temperature, and what elements can be added to prevent this from happening. The simulation was conducted using the chemical equilibrium solver Cantera with a Matlab front-end. Solutions were obtained by running equilibrations at constant temperature and constant specific volume over the specified range of temperatures. It was found that if nothing is done, carbon will deposit on the walls once it cools to below 2138K, and lead below 838K. Three solutions to capture the carbon were found: adding pure oxygen, hydrogen/nitrogen combo, and adding pure nitrogen. The best of these was the addition of oxygen which would readily form CO at around 4000K. To determine the temperature at which carbon would deposit on the walls, temperature solutions to evaporation rate equations needed to be found. To determine how much carbon or any species was in the chamber at a given time, chamber flushing equations needed to be developed. Major concerns are deposition of carbon and/or oxygen on the tungsten walls forming tungsten oxides or tungsten carbide which could cause embrittlement and cause failure of the first wall. Further research is needed.

  9. Nitrogen additions affect litter quality and soil biochemical properties in a peatland of Northeast China

    Science.gov (United States)

    Song, Yanyu; Song, Changchun; Meng, Henan; Swarzenski, Christopher M.; Wang, Xianwei; Tan, Wenwen

    2017-01-01

    Nitrogen (N) is a limiting nutrient in many peatland ecosystems. Enhanced N deposition, a major component of global climate change, affects ecosystem carbon (C) balance and alters soil C storage by changing plant and soil properties. However, the effects of enhanced N deposition on peatland ecosystems are poorly understood. We conducted a two-year N additions field experiment in a peatland dominated by Eriophorum vaginatum in the Da Xing’an Mountains, Northeast China. Four levels of N treatments were applied: (1) CK (no N added), (2) N1 (6 g N m−2 yr−1), (3) N2 (12 g N m−2 yr−1), and (4) N3 (24 g N m−2  yr−1). Plant and soil material was harvested at the end of the second growing season. N additions increased litter N and phosphorus (P) content, as well as β-glucosidase, invertase, and acid-phosphatase activity, but decreased litter C:N and C:P ratios. Litter carbon content remained unchanged. N additions increased available NH4+–N and NO3−–N as well as total Gram-positive (Gram+), Gram-negative (Gram−), and total bacterial phospholipid fatty acids (PLFA) in shallow soil (0–15 cm depth). An increase in these PLFAs was accompanied by a decrease in soil labile organic C (microbial biomass carbon and dissolved organic carbon), and appeared to accelerate decomposition and reduce the stability of the soil C pool. Invertase and urease activity in shallow soils and acid-phosphatase activity in deep soils (15–30 cm depth) was inhibited by N additions. Together, these findings suggest that an increase in N deposition in peatlands could accelerate litter decomposition and the loss of labile C, as well as alter microbial biomass and function.

  10. Enhancement of carbon sequestration in soil in the temperature grasslands of northern China by addition of nitrogen and phosphorus.

    Science.gov (United States)

    He, Nianpeng; Yu, Qiang; Wang, Ruomeng; Zhang, Yunhai; Gao, Yang; Yu, Guirui

    2013-01-01

    Increased nitrogen (N) deposition is common worldwide. Questions of where, how, and if reactive N-input influences soil carbon (C) sequestration in terrestrial ecosystems are of great concern. To explore the potential for soil C sequestration in steppe region under N and phosphorus (P) addition, we conducted a field experiment between 2006 and 2012 in the temperate grasslands of northern China. The experiment examined 6 levels of N (0-56 g N m(-2) yr(-1)), 6 levels of P (0-12.4 g P m(-2) yr(-1)), and a control scenario. Our results showed that addition of both N and P enhanced soil total C storage in grasslands due to significant increases of C input from litter and roots. Compared with control plots, soil organic carbon (SOC) in the 0-100 cm soil layer varied quadratically, from 156.8 to 1352.9 g C m(-2) with N addition gradient (R(2) = 0.99, P Soil inorganic carbon (SIC) decreased quadratically with N addition. The net C sequestration on grassland (including plant, roots, SIC, and SOC) increased linearly from -128.6 to 729.0 g C m(-2) under N addition (R(2) = 0.72, P = 0.023); and increased logarithmically, from 248.5 to 698 g C m(-2)under P addition (R(2) = 0.82, P = 0.014). Our study implies that N addition has complex effects on soil carbon dynamics, and future studies of soil C sequestration on grasslands should include evaluations of both SOC and SIC under various scenarios.

  11. Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests.

    Science.gov (United States)

    Cusack, Daniela F; Silver, Whendee L; Torn, Margaret S; Burton, Sarah D; Firestone, Mary K

    2011-03-01

    Microbial communities and their associated enzyme activities affect the amount and chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly in N-rich tropical forests, is likely to change the composition and behavior of microbial communities and feed back on ecosystem structure and function. This study presents a novel assessment of mechanistic links between microbial responses to N deposition and shifts in soil organic matter (SOM) quality and quantity. We used phospholipid fatty acid (PLFA) analysis and microbial enzyme assays in soils to assess microbial community responses to long-term N additions in two distinct tropical rain forests. We used soil density fractionation and 13C nuclear magnetic resonance (NMR) spectroscopy to measure related changes in SOM pool sizes and chemical quality. Microbial biomass increased in response to N fertilization in both tropical forests and corresponded to declines in pools of low-density SOM. The chemical quality of this soil C pool reflected ecosystem-specific changes in microbial community composition. In the lower-elevation forest, there was an increase in gram-negative bacteria PLFA biomass, and there were significant losses of labile C chemical groups (O-alkyls). In contrast, the upper-elevation tropical forest had an increase in fungal PLFAs with N additions and declines in C groups associated with increased soil C storage (alkyls). The dynamics of microbial enzymatic activities with N addition provided a functional link between changes in microbial community structure and SOM chemistry. Ecosystem-specific changes in microbial community composition are likely to have far-reaching effects on soil carbon storage and cycling. This study indicates that microbial communities in N-rich tropical forests can be sensitive to added N, but we can expect significant variability in how ecosystem structure and function respond to N deposition among tropical forest types.

  12. Quantifying the production of dissolved organic nitrogen in headwater streams using 15N tracer additions

    Science.gov (United States)

    Laura T. Johnson; Jennifer L. Tank; Robert O. Hall; Patrick J. Mullholland; Stephen K. Hamilton; H. Maurice Valett; Jackson R. Webster; Melody J. Bernot; William H. McDowell; Bruce J. Peterson; Suzanne M. Thomas

    2013-01-01

    Most nitrogen (N) assimilation in lake and marine ecosystems is often subsequently released via autochthonous dissolved organic nitrogen (DON) production, but autochthonous DON production has yet to be quantified in flowing waters. We measured in-stream DON production following 24 h 15N-nitrate (NO3-...

  13. Transcriptomic response of the red tide dinoflagellate, Karenia brevis, to nitrogen and phosphorus depletion and addition

    Directory of Open Access Journals (Sweden)

    Johnson Jillian G

    2011-07-01

    Full Text Available Abstract Background The role of coastal nutrient sources in the persistence of Karenia brevis red tides in coastal waters of Florida is a contentious issue that warrants investigation into the regulation of nutrient responses in this dinoflagellate. In other phytoplankton studied, nutrient status is reflected by the expression levels of N- and P-responsive gene transcripts. In dinoflagellates, however, many processes are regulated post-transcriptionally. All nuclear encoded gene transcripts studied to date possess a 5' trans-spliced leader (SL sequence suggestive, based on the trypanosome model, of post-transcriptional regulation. The current study therefore sought to determine if the transcriptome of K. brevis is responsive to nitrogen and phosphorus and is informative of nutrient status. Results Microarray analysis of N-depleted K. brevis cultures revealed an increase in the expression of transcripts involved in N-assimilation (nitrate and ammonium transporters, glutamine synthetases relative to nutrient replete cells. In contrast, a transcriptional signal of P-starvation was not apparent despite evidence of P-starvation based on their rapid growth response to P-addition. To study transcriptome responses to nutrient addition, the limiting nutrient was added to depleted cells and changes in global gene expression were assessed over the first 48 hours following nutrient addition. Both N- and P-addition resulted in significant changes in approximately 4% of genes on the microarray, using a significance cutoff of 1.7-fold and p ≤ 10-4. By far, the earliest responding genes were dominated in both nutrient treatments by pentatricopeptide repeat (PPR proteins, which increased in expression up to 3-fold by 1 h following nutrient addition. PPR proteins are nuclear encoded proteins involved in chloroplast and mitochondria RNA processing. Correspondingly, other functions enriched in response to both nutrients were photosystem and ribosomal genes

  14. Plant and microbial responses to nitrogen and phosphorus addition across an elevational gradient in subarctic tundra.

    Science.gov (United States)

    Sundqvist, Maja K; Liu, Zhanfeng; Giesler, Reiner; Wardle, David A

    2014-07-01

    Temperature and nutrients are major limiting factors in subarctic tundra. Experimental manipulation of nutrient availability along elevational gradients (and thus temperature) can improve our understanding of ecological responses to climate change. However, no study to date has explored impacts of nutrient addition along a tundra elevational gradient, or across contrasting vegetation types along any elevational gradient. We set up a full factorial nitrogen (N) and phosphorus (P) fertilization experiment in each of two vegetation types (heath and meadow) at 500 m, 800 m, and 1000 m elevation in northern Swedish tundra. We predicted that plant and microbial communities in heath or at lower elevations would be more responsive to N addition while communities in meadow or at higher elevations would be more responsive to P addition, and that fertilizer effects would vary more with elevation for the heath than for the meadow. Although our results provided little support for these predictions, the relationship between nutrient limitation and elevation differed between vegetation types. Most plant and microbial properties were responsive to N and/or P fertilization, but responses often varied with elevation and/or vegetation type. For instance, vegetation density significantly increased with N + P fertilization relative to the other fertilizer treatments, and this increase was greatest at the lowest elevation for the heath but at the highest elevation for the meadow. Arbuscular mycorrhizae decreased with P fertilization at 500 m for the meadow, but with all fertilizer treatments in both vegetation types at 800 m. Fungal to bacterial ratios were enhanced by N+ P fertilization for the two highest elevations in the meadow only. Additionally, microbial responses to fertilization were primarily direct rather than indirect via plant responses, pointing to a decoupled response of plant and microbial communities to nutrient addition and elevation. Because our study shows how two

  15. Effects of nitrogen additions on above- and belowground carbon dynamics in two tropical forests

    Energy Technology Data Exchange (ETDEWEB)

    Cusack, D.; Silver, W.L.; Torn, M.S.; McDowell, W.H.

    2011-04-15

    Anthropogenic nitrogen (N) deposition is increasing rapidly in tropical regions, adding N to ecosystems that often have high background N availability. Tropical forests play an important role in the global carbon (C) cycle, yet the effects of N deposition on C cycling in these ecosystems are poorly understood. We used a field N-fertilization experiment in lower and upper elevation tropical rain forests in Puerto Rico to explore the responses of above- and belowground C pools to N addition. As expected, tree stem growth and litterfall productivity did not respond to N fertilization in either of these Nrich forests, indicating a lack of N limitation to net primary productivity (NPP). In contrast, soil C concentrations increased significantly with N fertilization in both forests, leading to larger C stocks in fertilized plots. However, different soil C pools responded to N fertilization differently. Labile (low density) soil C fractions and live fine roots declined with fertilization, while mineral-associated soil C increased in both forests. Decreased soil CO2 fluxes in fertilized plots were correlated with smaller labile soil C pools in the lower elevation forest (R2 = 0.65, p\\0.05), and with lower live fine root biomass in the upper elevation forest (R2 = 0.90, p\\0.05). Our results indicate that soil C storage is sensitive to N deposition in tropical forests, even where plant productivity is not N-limited. The mineral-associated soil C pool has the potential to respond relatively quickly to N additions, and can drive increases in bulk soil C stocks in tropical forests.

  16. The response of heterotrophic activity and carbon cycling to nitrogen additions and warming in two tropical soils

    Science.gov (United States)

    Daniela F. Cusack; Margaret S. Torn; William H. McDowell; Whendee L. Silver

    2010-01-01

    Nitrogen (N) deposition is projected to increase significantly in tropical regions in the coming decades, where changes in climate are also expected. Additional N and warming each have the potential to alter soil carbon (C) storage via changes in microbial activity and decomposition, but little is known about the combined effects of these global change factors in...

  17. Dynamics of soil inorganic nitrogen and their responses to nitrogen additions in three subtropical forests, south China

    DEFF Research Database (Denmark)

    Fang, Yun-ting; Zhu, Wei-xing; Mo, Jiang-ming

    2006-01-01

    Three forests with different historical land-use, forest age, and species assemblages in subtropical China were selected to evaluate current soil N status and investigate the responses of soil inorganic N dynamics to monthly ammonium nitrate additions. Results showed that the mature monsoon...... evergreen broadleaved forest that has been protected for more than 400 years exhibited an advanced soil N status than the pine (Pinus massoniana) and pine-broadleaf mixed forests, both originated from the 1930's clear-cut and pine plantation. Mature forests had greater extractable inorganic N pool, lower N...... retention capacity, higher inorganic N leaching, and higher soil C/N ratios. Mineral soil extractable NH4+-N and NO3--N concentrations were significantly increased by experimental N additions on several sampling dates, but repeated ANOVA showed that the effect was not significant over the whole year except...

  18. Nitrogen Additions Increase the Diversity of Carbon Compounds Degraded by Fungi in Boreal Forests

    Science.gov (United States)

    Gartner, T. B.; Turner, K. M.; Treseder, K. K.

    2004-12-01

    Boreal forest soils in North America harbor a large reservoir of organic C, and this region is increasingly exposed to long-range atmospheric N transport from Eurasia. By examining the responses of decomposers to N deposition in these forests, we hope to improve predictions of the fate of boreal carbon pools under global change. We tested the hypothesis that the functional diversity of decomposer fungi would increase under N fertilization in boreal forests where fungal growth was otherwise N-limited, owing to a reduction in competitive exclusion of fungal groups. We collected soil and leaf litter from three Alaskan sites that represent different successional stages at 5, 17, or 80 years following severe forest fire. Each site had been exposed for two years to nitrogen and phosphorus fertilization in a factorial design, with four plots per treatment. Nutrient limitation of fungal growth varied depending on successional stage. The standing hyphal length of decomposer fungi in soil (i.e. Ascomycota and Basidiomycota) responded to neither N nor P in the 5-year old site, increased under N fertilization in the 17-year old site, and increased where N and P was added simultaneously in the 80-year old site (site x N x P interaction: P = 0.001). We used BIOLOG microplates for filamentous fungi to obtain an index of the diversity of carbon use by decomposer fungi; each of 95 wells of these plates contains a different carbon-based compound, as well as a dye that changes color upon metabolism of the compound. Saline leaf litter extracts were mixed with fungal growth medium and then added to the microplates. The number of wells displaying metabolic activity was counted following incubation for five days. We found that N fertilization raised the average number of positive wells per plate from 14 to 27 (P = 0.012), with no significant differences in responses among sites. Phosphorus additions did not alter functional diversity of fungi in any site. Since increases in functional

  19. Nitrogen and phosphorus additions alter nutrient dynamics but not resorption efficiencies of Chinese fir leaves and twigs differing in age.

    Science.gov (United States)

    Chen, Fu-Sheng; Niklas, Karl Joseph; Liu, Yu; Fang, Xiang-Min; Wan, Song-Ze; Wang, Huimin

    2015-10-01

    It is unclear how or even if phosphorus (P) input alters the influence of nitrogen (N) deposition in a forest. In theory, nutrients in leaves and twigs differing in age may show different responses to elevated nutrient input. To test this possibility, we selected Chinese fir (Cunninghamia lanceolata) for a series of N and P addition experiments using treatments of +N1 - P (50 kg N ha(-1) year(-1)), +N2 - P (100 kg N ha(-1) year(-1)), -N + P (50 kg P ha(-1) year(-1)), +N1 + P, +N2 + P and -N - P (without N and P addition). Soil samples were analyzed for mineral N and available P concentrations. Leaves and twigs in summer and their litters in winter were classified as and sorted into young and old components to measure N and P concentrations. Soil mineral N and available P increased with N and P additions, respectively. Nitrogen addition increased leaf and twig N concentrations in the second year, but not in the first year; P addition increased leaf and twig P concentrations in both years and enhanced young but not old leaf and twig N accumulations. Nitrogen and P resorption proficiencies in litters increased in response to N and P additions, but N and P resorption efficiencies were not significantly altered. Nitrogen resorption efficiency was generally higher in leaves than in twigs and in young vs old leaves and twigs. Phosphorus resorption efficiency showed a minimal variation from 26.6 to 47.0%. Therefore, P input intensified leaf and twig N enrichment with N addition, leaf and twig nutrients were both gradually resorbed with aging, and organ and age effects depended on the extent of nutrient limitation. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Effect of nitrogen addition on the performance of microbial fuel cell anodes

    KAUST Repository

    Saito, Tomonori

    2011-01-01

    Carbon cloth anodes were modified with 4(N,N-dimethylamino)benzene diazonium tetrafluoroborate to increase nitrogen-containing functional groups at the anode surface in order to test whether the performance of microbial fuel cells (MFCs) could be improved by controllably modifying the anode surface chemistry. Anodes with the lowest extent of functionalization, based on a nitrogen/carbon ratio of 0.7 as measured by XPS, achieved the highest power density of 938mW/m2. This power density was 24% greater than an untreated anode, and similar to that obtained with an ammonia gas treatment previously shown to increase power. Increasing the nitrogen/carbon ratio to 3.8, however, decreased the power density to 707mW/m2. These results demonstrate that a small amount of nitrogen functionalization on the carbon cloth material is sufficient to enhance MFC performance, likely as a result of promoting bacterial adhesion to the surface without adversely affecting microbial viability or electron transfer to the surface. © 2010 Elsevier Ltd.

  1. Effects of nitrogen additions on above- and belowground carbon dynamics in two tropical forests

    Science.gov (United States)

    Daniela F. Cusack; Whendee L. Silver; Margaret S. Torn; William H. McDowell

    2011-01-01

    Anthropogenic nitrogen (N) deposition is increasing rapidly in tropical regions, adding N to ecosystems that often have high background N availability. Tropical forests play an important role in the global carbon (C) cycle, yet the effects of N deposition on C cycling in these ecosystems are poorly understood. We used a field N-fertilization experiment in lower and...

  2. Nitrogen Addition and Warming Independently Influence the Belowground Micro-Food Web in a Temperate Steppe

    NARCIS (Netherlands)

    Li, Q.; Bai, H.; Liang, W.; Xia, J.; Wan, S.; Putten, van der W.H.

    2013-01-01

    Climate warming and atmospheric nitrogen (N) deposition are known to influence ecosystem structure and functioning. However, our understanding of the interactive effect of these global changes on ecosystem functioning is relatively limited, especially when it concerns the responses of soils and soil

  3. Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests

    Science.gov (United States)

    Daniela F. Cusack; Whendee L. Silver; Margaret S. Torn; Sarah D. Burton; Mary K. Firestone

    2011-01-01

    Microbial communities and their associated enzyme activities affect the amount and chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly in N-rich tropical forests, is likely to change the composition and behavior of microbial communities and feed back on ecosystem structure and function. This study presents a novel assessment of...

  4. Nitrogen

    Science.gov (United States)

    Apodaca, L.E.

    2010-01-01

    Ammonia was produced by 13 companies at 23 plants in 16 states during 2009. Sixty percent of all U.S. ammonia production capacity was centered in Louisiana. Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2009, U.S. producers operated at about 83 percent of their rated capacity (excluding plants that were idle for the entire year). Five companies — Koch Nitrogen Co.; Terra Industries Inc.; CF Industries Inc.; PCS Nitrogen Inc. and Agrium Inc., in descending order — accounted for 80 percent of the total U.S. ammonia production capacity. U.S. production was estimated to be 7.7 Mt (8.5 million st) of nitrogen (N) content in 2009 compared with 7.85 Mt (8.65 million st) of N content in 2008. Apparent consumption was estimated to have decreased to 12.1 Mt (13.3 million st) of N, a 10-percent decrease from 2008. The United States was the world's fourth-ranked ammonia producer and consumer following China, India and Russia. Urea, ammonium nitrate, ammonium phosphates, nitric acid and ammonium sulfate were the major derivatives of ammonia in the United States, in descending order of importance.

  5. Effects of N2O and O2 addition to nitrogen Townsend dielectric barrier discharges at atmospheric pressure on the absolute ground-state atomic nitrogen density

    KAUST Repository

    Es-sebbar, Et-touhami

    2012-11-27

    Absolute ground-state density of nitrogen atoms N (2p3 4S3/2) in non-equilibrium Townsend dielectric barrier discharges (TDBDs) at atmospheric pressure sustained in N2/N2O and N2/O2 gas mixtures has been measured using Two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. The quantitative measurements have been obtained by TALIF calibration using krypton as a reference gas. We previously reported that the maximum of N (2p3 4S3/2) atom density is around 3 × 1014 cm-3 in pure nitrogen TDBD, and that this maximum depends strongly on the mean energy dissipated in the gas. In the two gas mixtures studied here, results show that the absolute N (2p3 4S3/2) density is strongly affected by the N2O and O2 addition. Indeed, the density still increases exponentially with the energy dissipated in the gas but an increase in N2O and O2 amounts (a few hundreds of ppm) leads to a decrease in nitrogen atom density. No discrepancy in the order of magnitude of N (2p3 4S3/2) density is observed when comparing results obtained in N2/N2O and N2/O2 mixtures. Compared with pure nitrogen, for an energy of ∼90 mJ cm-3, the maximum of N (2p3 4S3/2) density drops by a factor of 3 when 100 ppm of N2O and O2 are added and it reduces by a factor of 5 for 200 ppm, to reach values close to our TALIF detection sensitivity for 400 ppm (1 × 1013 cm -3 at atmospheric pressure). © 2013 IOP Publishing Ltd.

  6. Long-term nitrogen additions increase likelihood of climate stress and affect recovery from wildfire in a lowland heath.

    Science.gov (United States)

    Southon, Georgina E; Green, Emma R; Jones, Alan G; Barker, Chris G; Power, Sally A

    2012-09-01

    Increases in the emissions and associated atmospheric deposition of nitrogen (N) have the potential to cause significant changes to the structure and function of N-limited ecosystems. Here, we present the results of a long-term (13 year) experiment assessing the impacts of N addition (30 kg ha(-1)  yr(-1) ) on a UK lowland heathland under a wide range of environmental conditions, including the occurrence of prolonged natural drought episodes and a severe summer fire. Our findings indicate that elevated N deposition results in large, persistent effects on Calluna growth, phenology and chemistry, severe suppression of understorey lichen flora and changes in soil biogeochemistry. Growing season rainfall was found to be a strong driver of inter-annual variation in Calluna growth and, although interactions between N and rainfall for shoot growth were not significant until the later phase of the experiment, N addition exacerbated the extent of drought injury to Calluna shoots following naturally occurring droughts in 2003 and 2009. Following a severe wildfire at the experimental site in 2006, heathland regeneration dynamics were significantly affected by N, with a greater abundance of pioneering moss species and suppression of the lichen flora in plots receiving N additions. Significant interactions between climate and N were also apparent post fire, with the characteristic stimulation in Calluna growth in +N plots suppressed during dry years. Carbon (C) and N budgets demonstrate large increases in both above- and below-ground stocks of these elements in N-treated plots prior to the fire, despite higher levels of soil microbial activity and organic matter turnover. Although much of the organic material was removed during the fire, pre-existing treatment differences were still evident following the burn. Post fire accumulation of below-ground C and N stocks was increased rapidly in N-treated plots, highlighting the role of N deposition in ecosystem C sequestration.

  7. The effect of nitrogen addition on biomass production and competition in three expansive tall grasses

    Czech Academy of Sciences Publication Activity Database

    Holub, Petr; Tůma, I.; Fiala, Karel

    2012-01-01

    Roč. 170, NOV 2012 (2012), s. 211-216 ISSN 0269-7491 R&D Projects: GA ČR(CZ) GA526/06/0556; GA MZe QJ1220007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67985939 ; RVO:67179843 Keywords : aboveground biomass * aggressivity * crowding coefficient * Nitrogen * tall grasses Subject RIV: EH - Ecology, Behaviour; EF - Botanics (BU-J) Impact factor: 3.730, year: 2012

  8. Nitrogen addition, not initial phylogenetic diversity, increases litter decomposition by fungal communities

    Directory of Open Access Journals (Sweden)

    Anthony Stuart Amend

    2015-02-01

    Full Text Available Fungi play a critical role in the degradation of organic matter. Because different combinations of fungi result in different rates of decomposition, determining how climate change will affect microbial composition and function is fundamental to predicting future environments. Fungal response to global change is patterned by genetic relatedness, resulting in communities with comparatively low phylogenetic diversity. This may have important implications for the functional capacity of disturbed communities if lineages sensitive to disturbance also contain unique traits important for litter decomposition. Here we tested the relationship between phylogenetic diversity and decomposition rates. Leaf litter fungi were isolated from the field and deployed in microcosms as mock communities along a gradient of initial phylogenetic diversity, while species richness was held constant. Replicate communities were subject to nitrogen fertilization comparable to anthropogenic deposition levels. Carbon mineralization rates were measured over the course of sixty-six days. We found that nitrogen fertilization increased cumulative respiration by 24.8%, and that differences in respiration between fertilized and ambient communities diminished over the course of the experiment. Initial phylogenetic diversity failed to predict respiration rates or their change in response to nitrogen fertilization, and there was no correlation between community similarity and respiration rates. Last, we detected no phylogenetic signal in the contributions of individual isolates to respiration rates. Our results suggest that the degree to which phylogenetic diversity predicts ecosystem function will depend on environmental context.

  9. Nitrogen addition, not initial phylogenetic diversity, increases litter decomposition by fungal communities.

    Science.gov (United States)

    Amend, Anthony S; Matulich, Kristin L; Martiny, Jennifer B H

    2015-01-01

    Fungi play a critical role in the degradation of organic matter. Because different combinations of fungi result in different rates of decomposition, determining how climate change will affect microbial composition and function is fundamental to predicting future environments. Fungal response to global change is patterned by genetic relatedness, resulting in communities with comparatively low phylogenetic diversity (PD). This may have important implications for the functional capacity of disturbed communities if lineages sensitive to disturbance also contain unique traits important for litter decomposition. Here we tested the relationship between PD and decomposition rates. Leaf litter fungi were isolated from the field and deployed in microcosms as mock communities along a gradient of initial PD, while species richness was held constant. Replicate communities were subject to nitrogen fertilization comparable to anthropogenic deposition levels. Carbon mineralization rates were measured over the course of 66 days. We found that nitrogen fertilization increased cumulative respiration by 24.8%, and that differences in respiration between fertilized and ambient communities diminished over the course of the experiment. Initial PD failed to predict respiration rates or their change in response to nitrogen fertilization, and there was no correlation between community similarity and respiration rates. Last, we detected no phylogenetic signal in the contributions of individual isolates to respiration rates. Our results suggest that the degree to which PD predicts ecosystem function will depend on environmental context.

  10. Effects of belowground litter addition, increased precipitation and clipping on soil carbon and nitrogen mineralization in a temperate steppe

    OpenAIRE

    Ma, L.; Guo, C.; Xin, X.; Yuan, S.; Wang, R.

    2013-01-01

    Soil carbon (C) and nitrogen (N) cycling are sensitive to changes in environmental factors and play critical roles in the responses of terrestrial ecosystems to natural and anthropogenic perturbations. This study was conducted to quantify the effects of belowground particulate litter (BPL) addition, increased precipitation and their interactions on soil C and N mineralization in two adjacent sites where belowground photosynthate allocation was manipulated through vegetation ...

  11. Effects of additive application upon ad libitum intake, in vivo digestibility and nitrogen balance of alfalfa haylage

    Directory of Open Access Journals (Sweden)

    Mladen Knežević

    2009-09-01

    Full Text Available The research objective was to determine the effect of the additive Sill-All application on ad libitum intake, in vivo digestibility and nitrogen balance of alfalfa haylage. About 40 % alfalfa plants was ensiled at the phonological flowering stage into plastic foil-wrapped bales without or with additive (2 L t-1 plant mass. No statistically significant differences were found between alfalfa ensiled without additive and alfalfa ensiled with additive for the content of dry matter (DM (632 g and 631 g DM kg-1 fresh sample, respectively. Alfalfa ensiled without additive contained 921 g organic matter (OM kg-1 DM, which was significantly higher (P<0.001 compared to alfalfa ensiled with additive (902 g OM kg-1 DM. Alfalfa ensiled without additive contained 141 g crude proteins (CP kg-1 DM, which was significantly higher (P<0.001 compared to alfalfa ensiled with additive (139 g CP kg-1 DM. Alfalfa ensiled with additive contained significantly less acid detergent fibers (ADF (P<0.001 compared to alfalfa ensiled without additive (445 g kg-1 DM and 456 g kg-1 DM, respectively and had a lower pH value (P<0.001 (5.29 and 5.56, respectively. No statistically significant differences were found between the studied feeding treatments for ad libitum intake of fresh ration and DM ration, for the measured parameters of digestibility and N balance. It was concluded that addition of the additive to alfalfa haylage led to significant changes in chemical composition; however, changes in chemical composition had no impact on measured biological parameters (ad libitum intake, in vivo digestibility and nitrogen balance.

  12. Effects of nitrogen and phosphorus additions on soil microbial biomass and community structure in two reforested tropical forests

    Science.gov (United States)

    Liu, Lei; Gundersen, Per; Zhang, Wei; Zhang, Tao; Chen, Hao; Mo, Jiangming

    2015-09-01

    Elevated nitrogen (N) deposition may aggravate phosphorus (P) deficiency in forests in the warm humid regions of China. To our knowledge, the interactive effects of long-term N deposition and P availability on soil microorganisms in tropical replanted forests remain unclear. We conducted an N and P manipulation experiment with four treatments: control, N addition (15 g N m-2·yr-1), P addition (15 g P m-2·yr-1), and N and P addition (15 + 15 g N and P m-2·yr-1, respectively) in disturbed (planted pine forest with recent harvests of understory vegetation and litter) and rehabilitated (planted with pine, but mixed with broadleaf returning by natural succession) forests in southern China. Nitrogen addition did not significantly affect soil microbial biomass, but significantly decreased the abundance of gram-negative bacteria PLFAs in both forest types. Microbial biomass increased significantly after P addition in the disturbed forest but not in the rehabilitated forest. No interactions between N and P additions on soil microorganisms were observed in either forest type. Our results suggest that microbial growth in replanted forests of southern China may be limited by P rather than by N, and this P limitation may be greater in disturbed forests.

  13. Effects of elevated carbon dioxide and nitrogen addition on foliar stoichiometry of nitrogen and phosphorus of five tree species in subtropical model forest ecosystems

    International Nuclear Information System (INIS)

    Huang Wenjuan; Zhou Guoyi; Liu Juxiu; Zhang Deqiang; Xu Zhihong; Liu Shizhong

    2012-01-01

    The effects of elevated carbon dioxide (CO 2 ) and nitrogen (N) addition on foliar N and phosphorus (P) stoichiometry were investigated in five native tree species (four non-N 2 fixers and one N 2 fixer) in open-top chambers in southern China from 2005 to 2009. The high foliar N:P ratios induced by high foliar N and low foliar P indicate that plants may be more limited by P than by N. The changes in foliar N:P ratios were largely determined by P dynamics rather than N under both elevated CO 2 and N addition. Foliar N:P ratios in the non-N 2 fixers showed some negative responses to elevated CO 2 , while N addition reduced foliar N:P ratios in the N 2 fixer. The results suggest that N addition would facilitate the N 2 fixer rather than the non-N 2 fixers to regulate the stoichiometric balance under elevated CO 2 . - Highlights: ► Five native tree species in southern China were more limited by P than by N. ► Shifts in foliar N:P ratios were driven by P dynamic under the global change. ► N addition lowered foliar N:P ratios in the N 2 fixer under elevated CO 2 . - N addition could facilitate the N 2 fixer rather than the non-N 2 fixers to regulate foliar N and P stoichiometry under elevated CO 2 in subtropical forests.

  14. Members of the LBD Family of Transcription Factors Repress Anthocyanin Synthesis and Affect Additional Nitrogen Responses in Arabidopsis

    OpenAIRE

    Rubin, G.; Tohge, T.; Matsuda, F.; Saito, K.; Scheible, W.

    2009-01-01

    Nitrogen (N) and nitrate (NO3-) per se regulate many aspects of plant metabolism, growth, and development. N/NO3- also suppresses parts of secondary metabolism, including anthocyanin synthesis. Molecular components for this repression are unknown. We report that three N/NO3--induced members of the LATERAL ORGAN BOUNDARY DOMAIN (LBD) gene family of transcription factors (LBD37, LBD38, and LBD39) act as negative regulators of anthocyanin biosynthesis in Arabidopsis thaliana. Overexpression of e...

  15. Combined effects of nitrogen addition and organic matter manipulation on soil respiration in a Chinese pine forest.

    Science.gov (United States)

    Wang, Jinsong; Wu, L; Zhang, Chunyu; Zhao, Xiuhai; Bu, Wensheng; Gadow, Klaus V

    2016-11-01

    The response of soil respiration (Rs) to nitrogen (N) addition is one of the uncertainties in modelling ecosystem carbon (C). We reported on a long-term nitrogen (N) addition experiment using urea (CO(NH 2 ) 2 ) fertilizer in which Rs was continuously measured after N addition during the growing season in a Chinese pine forest. Four levels of N addition, i.e. no added N (N0: 0 g N m -2  year -1 ), low-N (N1: 5 g N m -2  year -1 ), medium-N (N2: 10 g N m -2  year -1 ), and high-N (N3: 15 g N m -2  year -1 ), and three organic matter treatments, i.e. both aboveground litter and belowground root removal (LRE), only aboveground litter removal (LE), and intact soil (CK), were examined. The Rs was measured continuously for 3 days following each N addition application and was measured approximately 3-5 times during the rest of each month from July to October 2012. N addition inhibited microbial heterotrophic respiration by suppressing soil microbial biomass, but stimulated root respiration and CO 2 release from litter decomposition by increasing either root biomass or microbial biomass. When litter and/or root were removed, the "priming" effect of N addition on the Rs disappeared more quickly than intact soil. This is likely to provide a point of view for why Rs varies so much in response to exogenous N and also has implications for future determination of sampling interval of Rs measurement.

  16. Short-term nitrogen additions can shift a coastal wetland from a sink to a source of N2O

    Science.gov (United States)

    Moseman-Valtierra, Serena; Gonzalez, Rosalinda; Kroeger, Kevin D.; Tang, Jianwu; Chao, Wei Chun; Crusius, John; Bratton, John F.; Green, Adrian; Shelton, James

    2011-01-01

    Coastal salt marshes sequester carbon at high rates relative to other ecosystems and emit relatively little methane particularly compared to freshwater wetlands. However, fluxes of all major greenhouse gases (N2O, CH4, and CO2) need to be quantified for accurate assessment of the climatic roles of these ecosystems. Anthropogenic nitrogen inputs (via run-off, atmospheric deposition, and wastewater) impact coastal marshes. To test the hypothesis that a pulse of nitrogen loading may increase greenhouse gas emissions from salt marsh sediments, we compared N2O, CH4 and respiratory CO2fluxes from nitrate-enriched plots in a Spartina patens marsh (receiving single additions of NaNO3 equivalent to 1.4 g N m−2) to those from control plots (receiving only artificial seawater solutions) in three short-term experiments (July 2009, April 2010, and June 2010). In July 2009, we also compared N2O and CH4 fluxes in both opaque and transparent chambers to test the influence of light on gas flux measurements. Background fluxes of N2O in July 2009 averaged −33 μmol N2O m−2 day−1. However, within 1 h of nutrient additions, N2O fluxes were significantly greater in plots receiving nitrate additions relative to controls in July 2009. Respiratory rates and CH4 fluxes were not significantly affected. N2O fluxes were significantly higher in dark than in transparent chambers, averaging 108 and 42 μmol N2O m−2 day−1 respectively. After 2 days, when nutrient concentrations returned to background levels, none of the greenhouse gas fluxes differed from controls. In April 2010, N2O and CH4 fluxes were not significantly affected by nitrate, possibly due to higher nitrogen demands by growing S. patens plants, but in June 2010 trends of higher N2O fluxes were again found among nitrate-enriched plots, indicating that responses to nutrient pulses may be strongest during the summer. In terms of carbon equivalents, the highest average N2O and CH4 fluxes observed, exceeded half

  17. 78 FR 56695 - Proposed Listing of Additional Waters To Be Included on Indiana's 2010 List of Impaired Waters...

    Science.gov (United States)

    2013-09-13

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9900-95--Region 5] Proposed Listing of Additional Waters To Be Included on Indiana's 2010 List of Impaired Waters Under the Clean Water Act AGENCY: Environmental Protection Agency (EPA). ACTION: Reopening of comment period. SUMMARY: EPA is reopening the comment period...

  18. 78 FR 35929 - Proposed Listing of Additional Waters To Be Included on Indiana's 2010 List of Impaired Waters...

    Science.gov (United States)

    2013-06-14

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9823-3] Proposed Listing of Additional Waters To Be Included on Indiana's 2010 List of Impaired Waters Under Section 303(d) of the Clean Water Act AGENCY... comment. Section 303(d)(2) requires that states submit and EPA approve or disapprove lists of waters for...

  19. Nitrogen and phosphorus addition impact soil N2O emission in a secondary tropical forest of South China

    Science.gov (United States)

    Wang, Faming; Li, Jian; Wang, Xiaoli; Zhang, Wei; Zou, Bi; Neher, Deborah A.; Li, Zhian

    2014-01-01

    Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, few studies have explored impacts of N addition (aN), P addition (aP) and N×P interaction on tropical forests N2O fluxes. We established an N and P addition experiment in a tropical forest to test whether: (1) N addition would increase N2O emission and nitrification, and (2) P addition would increase N2O emission and N transformations. Nitrogen and P addition had no effect on N mineralization and nitrification. Soil microbial biomass was increased following P addition in wet seasons. aN increased 39% N2O emission as compared to control (43.3 μgN2O-N m−2h−1). aP did not increase N2O emission. Overall, N2O emission was 60% greater for aNP relative to the control, but significant difference was observed only in wet seasons, when N2O emission was 78% greater for aNP relative to the control. Our results suggested that increasing N deposition will enhance soil N2O emission, and there would be N×P interaction on N2O emission in wet seasons. Given elevated N deposition in future, P addition in this tropical soil will stimulate soil microbial activities in wet seasons, which will further enhance soil N2O emission. PMID:25001013

  20. Effect of Exogenous Nitrogen Addition on Nitrous Oxide N 2 O Emissions from Wetland Soil

    Directory of Open Access Journals (Sweden)

    SHI Hao-xian

    2014-10-01

    Full Text Available It is important to make sure key nitrogen driving N2O emission source from wetland soil for efficient N2O emission reduction. In lab-oratory, the temperature and humidity were kept constant to study effect from different forms of exogenous N on N2O emissions from wetland soil by gas chromatography. The results showed that all groups of exogenous N inputs increased N2O emissions from wetland soil in contrast to CK group(4.4 mg·m -3. Under the group urea(Ualone and the combination of urea with ammonium nitrate(UANin a 1:1 concentration ra-tio, the change of N2O emissions showed a unimodal trend, first increased and then decreased, the peak value 10.6 mg· m -3 and 229.0 mg·m -3 of N2 O emissions corresponded to U and of UAN, respectively. While N2O emissions showed an upward trend for ammonium nitrate(ANalone, within the range from 32.6 mg·m -3 to 111.0 mg·m -3 N2O emissions. All exogenous N treatments increased N2O emissions more than CK,UAN combination>AN alone>U alone. This provided a scientific basis for predicting greenhouse effect caused by N fertilizer in wetland soil from farming-pastoral transition zone, as well as a reference for effective reducing N2 O emissions from wetlands in Inner Mongolia Plateau.

  1. Nutrient addition differentially affects ecological processes of Avicennia germinans in nitrogen versus phosphorus limited mangrove ecosystems

    Science.gov (United States)

    Feller, Ilka C.; Lovelock, C.E.; McKee, K.L.

    2007-01-01

    Nutrient over-enrichment is a major threat to marine environments, but system-specific attributes of coastal ecosystems may result in differences in their sensitivity and susceptibility to eutrophication. We used fertilization experiments in nitrogen (N)- and phosphorus (P)-limited mangrove forests to test the hypothesis that alleviating different kinds of nutrient limitation may have different effects on ecosystem structure and function in natural systems. We compared a broad range of ecological processes to determine if these systems have different thresholds where shifts might occur in nutrient limitation. Growth responses indicated N limitation in Avicennia germinans (black mangrove) forests in the Indian River Lagoon (IRL), Florida, and P limitation at Twin Cays, Belize. When nutrient deficiency was relieved, A. germinans grew out of its stunted form by increasing wood relative to leaf biomass and shoot length relative to lateral growth. At the P-limited site, P enrichment (+P) increased specific leaf area, N resorption, and P uptake, but had no effect on P resorption. At the N-limited site, +N increased both N and P resorption, but did not alter biomass allocation. Herbivory was greater at the P-limited site and was unaffected by +P, whereas +N led to increased herbivory at the N-limited site. The responses to nutrient enrichment depended on the ecological process and limiting nutrient and suggested that N- versus P-limited mangroves do have different thresholds. +P had a greater effect on more ecological processes at Twin Cays than did +N at the IRL, which indicated that the P-limited site was more sensitive to nutrient loading. Because of this sensitivity, eutrophication is more likely to cause a shift in nutrient limitation at P-limited Twin Cays than N-limited IRL. ?? 2007 Springer Science+Business Media, LLC.

  2. Reducing nitrogen loss and phytotoxicity during beer vinasse composting with biochar addition.

    Science.gov (United States)

    Wang, Xueqin; Zhao, Yue; Wang, Huan; Zhao, Xinyu; Cui, Hongyang; Wei, Zimin

    2017-03-01

    The aim of this study was to investigate the feasibility of composting of beer vinasse generated from brewing industry, the effect of biochar amendment on beer vinasse composting was also evaluated based on the changes of different physicochemical parameters, phytotoxicity and final compost quality. Four different treatments were performed of beer vinasse with biochar addition at 0, 5%, 10%, 15% (w/w dry basis). The final product obtained from beer vinasse composting was phytotoxicity-free (GI: 120.8%), mature (C/N: 19.88, NH 4 + -N: 295.0mg/kg, DOC: 9.76g/kg) and nutrient-rich (especially for P: 1.92%) compost except high N loss (60.76%), which had the potential to be as soil amendment or fertilizer. Biochar addition contributed to decomposition of DOC indicating higher microbial activity and attain phytotoxicity-free standard rapidly. N loss significantly reduced by 27% with biochar at 15% addition. And 15% biochar addition ensured all parameters, which was involved in composts quality, to attain the mature standard. Therefore, it was suggested that biochar addition at 15% was optimal. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Response of dissolved carbon and nitrogen concentrations to moderate nutrient additions in a tropical montane forest of south Ecuador

    Directory of Open Access Journals (Sweden)

    Andre eVelescu

    2016-05-01

    Full Text Available In the past two decades, the tropical montane rain forests in south Ecuador experienced increasing deposition of reactive nitrogen mainly originating from Amazonian forest fires, while Saharan dust inputs episodically increased deposition of base metals. Increasing air temperature and unevenly distributed rainfall have allowed for longer dry spells in a perhumid ecosystem. This might have favored mineralization of dissolved organic matter (DOM by microorganisms and increased nutrient release from the organic layer. Environmental change is expected to impact the functioning of this ecosystem belonging to the biodiversity hotspots of the Earth.In 2007, we established a nutrient manipulation experiment (NUMEX to understand the response of the ecosystem to moderately increased nutrient inputs. Since 2008, we have continuously applied 50 kg ha-1 a-1 of nitrogen (N, 10 kg ha-1 a-1 of phosphorus (P, 50 kg + 10 kg ha-1 a-1 of N and P and 10 kg ha-1 a-1 of calcium (Ca in a randomized block design at 2000 m a.s.l. in a natural forest on the Amazonia-exposed slopes of the south Ecuadorian Andes.Nitrogen concentrations in throughfall increased following N+P additions, while separate N amendments only increased nitrate concentrations. Total organic carbon (TOC and dissolved organic nitrogen (DON concentrations showed high seasonal variations in litter leachate and decreased significantly in the P and N+P treatments, but not in the N treatment. Thus, P availability plays a key role in the mineralization of DOM. TOC/DON ratios were narrower in throughfall than in litter leachate but their temporal course did not respond to nutrient amendments.Our results revealed an initially fast, positive response of the C and N cycling to nutrient additions which declined with time. TOC and DON cycling only change if N and P supply are improved concurrently, while NO3-N leaching increases only if N is separately added. This indicates co-limitation of the microorganisms by N

  4. Response of dissolved carbon and nitrogen concentrations to moderate nutrient additions in a tropical montane forest of south Ecuador

    Science.gov (United States)

    Velescu, Andre; Valarezo, Carlos; Wilcke, Wolfgang

    2016-05-01

    In the past two decades, the tropical montane rain forests in south Ecuador experienced increasing deposition of reactive nitrogen mainly originating from Amazonian forest fires, while Saharan dust inputs episodically increased deposition of base metals. Increasing air temperature and unevenly distributed rainfall have allowed for longer dry spells in a perhumid ecosystem. This might have favored mineralization of dissolved organic matter (DOM) by microorganisms and increased nutrient release from the organic layer. Environmental change is expected to impact the functioning of this ecosystem belonging to the biodiversity hotspots of the Earth. In 2007, we established a nutrient manipulation experiment (NUMEX) to understand the response of the ecosystem to moderately increased nutrient inputs. Since 2008, we have continuously applied 50 kg ha-1 a-1 of nitrogen (N), 10 kg ha-1 a-1 of phosphorus (P), 50 kg + 10 kg ha-1 a-1 of N and P and 10 kg ha-1 a-1 of calcium (Ca) in a randomized block design at 2000 m a.s.l. in a natural forest on the Amazonia-exposed slopes of the south Ecuadorian Andes. Nitrogen concentrations in throughfall increased following N+P additions, while separate N amendments only increased nitrate concentrations. Total organic carbon (TOC) and dissolved organic nitrogen (DON) concentrations showed high seasonal variations in litter leachate and decreased significantly in the P and N+P treatments, but not in the N treatment. Thus, P availability plays a key role in the mineralization of DOM. TOC/DON ratios were narrower in throughfall than in litter leachate but their temporal course did not respond to nutrient amendments. Our results revealed an initially fast, positive response of the C and N cycling to nutrient additions which declined with time. TOC and DON cycling only change if N and P supply are improved concurrently, while NO3-N leaching increases only if N is separately added. This indicates co-limitation of the microorganisms by N and P

  5. Physiological responses to nitrogen and sulphur addition and raised temperature in Sphagnum balticum.

    Science.gov (United States)

    Granath, Gustaf; Wiedermann, Magdalena M; Strengbom, Joachim

    2009-09-01

    Sphagnum, the main genus which forms boreal peat, is strongly affected by N and S deposition and raised temperature, but the physiological mechanisms behind the responses are largely unknown. We measured maximum photosynthetic rate (NP(max)), maximum efficiency of photosystem II [variable fluorescence (F (v))/maximum fluorescence yield (F (m))] and concentrations of N, C, chlorophyll and carotenoids as responses to N and S addition and increased temperature in Sphagnum balticum (a widespread species in the northern peatlands) in a 12-year factorial experiment. NP(max) did not differ between control (0.2 g N m(-2) year(-1)) and high N (3.0 g N m(-2) year(-1)), but was higher in the mid N treatment (1.5 g N m(-2) year(-1)). N, C, carotenoids and chlorophyll concentration increased in shoot apices after N addition. F (v)/F (m) did not differ between N treatments. Increased temperature (+3.6 degrees C) had a small negative effect on N concentration, but had no significant effect on NP(max) or F (v)/F (m). Addition of 2 g S m(-2) year(-1) showed a weak negative effect on NP(max) and F (v)/F (m). Our results suggest a unimodal response of NP(max) to N addition and tissue N concentration in S. balticum, with an optimum N concentration for photosynthetic rate of ~13 mg N g(-1). In conclusion, high S deposition may reduce photosynthetic capacity in Sphagnum, but the negative effects may be relaxed under high N availability. We suggest that previously reported negative effects on Sphagnum productivity under high N deposition are not related to negative effects on the photosynthetic apparatus, but differences in optimum N concentration among Sphagnum species may affect their competitive ability under different N deposition regimes.

  6. Soil microbial community structure and nitrogen cycling responses to agroecosystem management and carbon substrate addition

    Science.gov (United States)

    Berthrong, S. T.; Buckley, D. H.; Drinkwater, L. E.

    2011-12-01

    Fertilizer application in conventional agriculture leads to N saturation and decoupled soil C and N cycling, whereas organic practices, e.g. complex rotations and legume incorporation, often results in increased SOM and tightly coupled cycles of C and N. These legacy effects of management on soils likely affect microbial community composition and microbial process rates. This project tested if agricultural management practices led to distinct microbial communities and if those communities differed in ability to utilize labile plant carbon substrates and to produce more plant available N. We addressed several specific questions in this project. 1) Do organic and conventional management legacies on similar soils produce distinct soil bacterial and fungal community structures and abundances? 2) How do these microbial community structures change in response to carbon substrate addition? 3) How do the responses of the microbial communities influence N cycling? To address these questions we conducted a laboratory incubation of organically and conventionally managed soils. We added C-13 labelled glucose either in one large dose or several smaller pulses. We extracted genomic DNA from soils before and after incubation for TRFLP community fingerprinting. We measured C in soil pools and respiration and N in soil extracts and leachates. Management led to different compositions of bacteria and fungi driven by distinct components in organic soils. Biomass did not differ across treatments indicating that differences in cycling were due to composition rather than abundance. C substrate addition led to convergence in bacterial communities; however management still strongly influenced the difference in communities. Fungal communities were very distinct between managements and plots with substrate addition not altering this pattern. Organic soils respired 3 times more of the glucose in the first week than conventional soils (1.1% vs 0.4%). Organic soils produced twice as much

  7. Utilization of nitrogen by soybean (Glycine max) influenced by the addition of sugar cane bagasse

    International Nuclear Information System (INIS)

    Bonetti, R.; Saito, S.M.T.

    1982-01-01

    N 2 -fixation in soybean and soil-N and 15 N-urea utilization where studied in a glasshouse. Doses of fertilizer were 0, 40 and 80 kgN/ha added either to cultivated - or virgin soil, where sugar cane bagasse was also added (20 ton/ha). Non-nodulating soybean was used as a control to determine the absorption of the three N-sources: soil, fertilizer and N 2 -fixation. The N-immobilization effect caused by bagasse addition was observed even after a pre-incubation period of 40 days, being greater in the cultivated than in the soil without organic matter. Accumulations of N, P and S where also smaller in these plants. Additions of N were not sufficient to equal the values observed in soils without organic matter. Addition of 40 kgN/ha showed a sinergistic and positive effect on treatments that had N-immobilization, reinforcing the idea that starter doses of N are necessary for maximization of nodulation and N 2 -fixation in soybean, in soils with low N. N 2 -fixation contributed with mean values of 54% and 84% N, respectively, in the aerial part and pools in non-treated soil. When bagasse was added, the percentages of N 2 -fixed increased, however in smaller amounts, showing a necessity of different sources of N to increase the total N in plant. The greatest N 2 -fixation (48,6 kgN/ha) was found in the cultivated soil, where only bagasse had been added. (M.A.) [pt

  8. Improved creep and oxidation behavior of a martensitic 9Cr steel by the controlled addition of boron and nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Mayr, Peter [Massachusetts Institute of Technology, Cambridge, MA (United States). Dept. of Materials Science; Graz Univ. of Technology (Austria). Inst. of Material Science and Welding; Holzer, Ivan; Mendez-Martin, Francisca [Graz Univ. of Technology (Austria). Inst. of Material Science and Welding; Albu, Mihaela; Mitsche, Stefan [Graz Univ. of Technology (Austria). Inst. for Electron Microscopy; Gonzalez, Vanessa; Agueero, Alina [Instituto Nacional de Tecnica Aeroespacial, Torrejon de Ardoz (Spain)

    2010-07-01

    This manuscript gives an overview on recent developments of a martensitic steel grade based on 9Cr3W3CoVNb with controlled additions of boron and nitrogen. Alloy design by thermodynamic equilibrium calculations and calculation of boron-nitrogen solubility is discussed. Out of this alloy design process, two melts of a 9Cr3W3CoVNbBN steel were produced. The investigation focused on microstructural evolution during high temperature exposure, creep properties and oxidation resistance in steam at 650 C. Microstructural characterization of ''as-received'' and creep exposed material was carried out using conventional optical as well as advanced electron microscopic methods. Creep data at 650 was obtained at various stress levels. Longest-running specimens have reached more than 20,000 hours of testing time. In parallel, long-term oxidation resistance has been studied at 650 C in steam atmosphere up to 5,000 hours. Preliminary results of the extensive testing program on a 9Cr3W3CoVNbBN steel show significant improvement in respect to creep strength and oxidation resistance compared to the state-of-the-art 9 wt. % Cr martensitic steel grades. Up to current testing times, the creep strength is significantly beyond the +20% scatterband of standard grade P92 material. Despite the chromium content of 9 wt % the material exhibits excellent oxidation resistance. Steam exposed plain base material shows comparable oxidation behavior to coated material, and the corrosion rate of the boron-nitrogen controlled steel is much lower compared to standard 9 wt % Cr steel grades, P91 and P92. (orig.)

  9. Different responses of soil respiration and its components to nitrogen addition among biomes: a meta-analysis.

    Science.gov (United States)

    Zhou, Lingyan; Zhou, Xuhui; Zhang, Baocheng; Lu, Meng; Luo, Yiqi; Liu, Lingli; Li, Bo

    2014-07-01

    Anthropogenic activities have increased nitrogen (N) deposition by threefold to fivefold over the last century, which may considerably affect soil respiration (Rs). Although numerous individual studies and a few meta-analyses have been conducted, it remains controversial as to how N addition affects Rs and its components [i.e., autotrophic (Ra) and heterotrophic respiration (Rh)]. To reconcile the difference, we conducted a comprehensive meta-analysis of 295 published studies to examine the responses of Rs and its components to N addition in terrestrial ecosystems. We also assessed variations in their responses in relation to ecosystem types, environmental conditions, and experimental duration (DUR). Our results show that N addition significantly increased Rs by 2.0% across all biomes but decreased by 1.44% in forests and increased by 7.84% and 12.4% in grasslands and croplands, respectively (P biomes with more stimulation of Ra in croplands and grasslands compared with no significant change in forests. Rh exhibited a similar negative response to N addition among biomes except that in croplands, tropical and boreal forests. Methods of partitioning Rs did not induce significant differences in the responses of Ra or Rh to N addition, except that Ra from root exclusion and component integration methods exhibited the opposite responses in temperate forests. The response ratios (RR) of Rs to N addition were positively correlated with mean annual temperature (MAT), with being more significant when MAT was less than 15 °C, but negatively with DUR. In addition, the responses of Rs and its components to N addition largely resulted from the changes in root and microbial biomass and soil C content as indicated by correlation analysis. The response patterns of Rs to N addition as revealed in this study can be benchmarks for future modeling and experimental studies. © 2013 John Wiley & Sons Ltd.

  10. Responses of ecosystem carbon dioxide exchange to nitrogen addition in a freshwater marshland in Sanjiang Plain, Northeast China.

    Science.gov (United States)

    Zhang, Lihua; Song, Changchun; Nkrumah, Philip N

    2013-09-01

    It has widely been documented that nitrogen (N) stimulates plant growth and net primary production. But how N affects net ecosystem CO2 exchange (NEE) is still dispute. We conduct an experimental study to assess the response of NEE to N addition in a freshwater marsh. Experimental treatments involved elevated N and control treatments on triplicate 1 m(2) plots. Gas exchange, air temperature, plant biomass and leaf area as well as N% of leaf were measured from 2004 to 2005. The results indicated that N addition initially decreased the CO2 sequestration but the trend changed in the second year. It was concluded that N addition enhanced the greenhouse effect in marshland as far as global warming potential (GWP) is concerned. This increase was attributed to a substantial increase in CH4 and N2O emissions after N addition. We recommended long-term studies to further clarify the effect of N addition on NEE. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Ubiquity of insect-derived nitrogen transfer to plants by endophytic insect-pathogenic fungi: an additional branch of the soil nitrogen cycle.

    Science.gov (United States)

    Behie, Scott W; Bidochka, Michael J

    2014-03-01

    The study of symbiotic nitrogen transfer in soil has largely focused on nitrogen-fixing bacteria. Vascular plants can lose a substantial amount of their nitrogen through insect herbivory. Previously, we showed that plants were able to reacquire nitrogen from insects through a partnership with the endophytic, insect-pathogenic fungus Metarhizium robertsii. That is, the endophytic capability and insect pathogenicity of M. robertsii are coupled so that the fungus acts as a conduit to provide insect-derived nitrogen to plant hosts. Here, we assess the ubiquity of this nitrogen transfer in five Metarhizium species representing those with broad (M. robertsii, M. brunneum, and M. guizhouense) and narrower insect host ranges (M. acridum and M. flavoviride), as well as the insect-pathogenic fungi Beauveria bassiana and Lecanicillium lecanii. Insects were injected with (15)N-labeled nitrogen, and we tracked the incorporation of (15)N into two dicots, haricot bean (Phaseolus vulgaris) and soybean (Glycine max), and two monocots, switchgrass (Panicum virgatum) and wheat (Triticum aestivum), in the presence of these fungi in soil microcosms. All Metarhizium species and B. bassiana but not L. lecanii showed the capacity to transfer nitrogen to plants, although to various degrees. Endophytic association by these fungi increased overall plant productivity. We also showed that in the field, where microbial competition is potentially high, M. robertsii was able to transfer insect-derived nitrogen to plants. Metarhizium spp. and B. bassiana have a worldwide distribution with high soil abundance and may play an important role in the ecological cycling of insect nitrogen back to plant communities.

  12. EVAPORATION: a new vapor pressure estimation method for organic molecules including non-additivity and intramolecular interactions

    Science.gov (United States)

    Compernolle, S.; Ceulemans, K.; Müller, J.-F.

    2011-04-01

    We present EVAPORATION (Estimation of VApour Pressure of ORganics, Accounting for Temperature, Intramolecular, and Non-additivity effects), a method to predict vapour pressure p0 of organic molecules needing only molecular structure as input. The method is applicable to zero-, mono- and polyfunctional molecules. A simple formula to describe log10p0(T) is employed, that takes into account both a wide temperature dependence and the non-additivity of functional groups. In order to match the recent data on functionalised diacids an empirical modification to the method was introduced. Contributions due to carbon skeleton, functional groups, and intramolecular interaction between groups are included. Molecules typically originating from oxidation of biogenic molecules are within the scope of this method: carbonyls, alcohols, ethers, esters, nitrates, acids, peroxides, hydroperoxides, peroxy acyl nitrates and peracids. Therefore the method is especially suited to describe compounds forming secondary organic aerosol (SOA).

  13. Growth and nitrogen acquisition strategies of Acacia senegal seedlings under exponential phosphorus additions.

    Science.gov (United States)

    Isaac, M E; Harmand, J M; Drevon, J J

    2011-05-15

    There remains conflicting evidence on the relationship between P supply and biological N(2)-fixation rates, particularly N(2)-fixing plant adaptive strategies under P limitation. This is important, as edaphic conditions inherent to many economically and ecologically important semi-arid leguminous tree species, such as Acacia senegal, are P deficient. Our research objective was to verify N acquisition strategies under phosphorus limitations using isotopic techniques. Acacia senegal var. senegal was cultivated in sand culture with three levels of exponentially supplied phosphorus [low (200 μmol of P seedling(-1) over 12 weeks), mid (400 μmol) and high (600 μmol)] to achieve steady-state nutrition over the growth period. Uniform additions of N were also supplied. Plant growth and nutrition were evaluated. Seedlings exhibited significantly greater total biomass under high P supply compared to low P supply. Both P and N content significantly increased with increasing P supply. Similarly, N derived from solution increased with elevated P availability. However, both the number of nodules and the N derived from atmosphere, determined by the (15)N natural abundance method, did not increase along the P gradient. Phosphorus stimulated growth and increased mineral N uptake from solution without affecting the amount of N derived from the atmosphere. We conclude that, under non-limiting N conditions, A. senegal N acquisition strategies change with P supply, with less reliance on N(2)-fixation when the rhizosphere achieves a sufficient N uptake zone. Copyright © 2010 Elsevier GmbH. All rights reserved.

  14. Responses of secondary chemicals in sugar maple (Acer saccharum) seedlings to UV-B, springtime warming and nitrogen additions

    Energy Technology Data Exchange (ETDEWEB)

    Sager, E.P.S.; Hutchinson, T.C. [Trent Univ., Peterborough, ON (Canada). Environmental Studies

    2006-10-15

    Elevated UV-B radiation due to climatic change and ozone depletion may represent a significant springtime environmental stressor to germinating seedlings in temperate forest regions. This study aimed to determine the effects of UV-B, nitrogen (N) fertilization and climate warming on the concentrations of base cations and secondary metabolites in the foliage of sugar maple seedlings growing in acid or alkaline soils. The influence of measured flavonoids and phenolics on herbivore activity was examined, as well as the relationship between foliar concentrations of calcium (Ca); manganese (Mn); and N and the production of phenolic and flavonoid compounds. Experimental plots were established in mature hardwood forests in alkaline and acid soil locations in Bobcaygeon and Haliburton, Ontario. Pentagonal open-top chambers were used to lengthen the growing season and simulate an earlier spring. Ammonium nitrate was applied at a rate comparable with an additional deposition of 5 g N per m per year. Fertilizer was applied on 3 separate occasions. Ambient UV-B radiation was screened out with Mylar D polyester film. Sites, treatments and time of sampling had complex effects on foliar elemental chemistry, production of secondary compounds and herbivory. Foliar concentrations of individual phenols were higher in seedlings in the UV-B exclusion treatments. At both sites, removal of ambient UV-B led to increases in flavonoids and chlorogenic acid, and reduced herbivore activity. At Haliburton, ammonium nitrate fertilization led to further increases in foliar Mn. Nitrogen additions led to decreases in the concentrations of some flavonoids at both sites. It was concluded that the composition of the forest soil governs the response of seedlings when they are exposed to abiotic stressors. 63 refs., 5 tabs., 8 figs.

  15. Effect of exogenous carbon addition and the freeze-thaw cycle on soil microbes and mineral nitrogen pools1

    Science.gov (United States)

    Hu, Xia; Yin, Peng; Nong, Xiang; Liao, Jinhua

    2018-01-01

    To elucidate the alpine soil process in winter, the response mechanism of soil mineral nitrogen and soil microbes to exogenous carbon (0 mg C, 1 mg C, 2 mg C, 4 mg C and 8 mg C·g-1 dry soil) and the freeze-thaw cycle (-2 °C, -2 ∼ 2 °C, -20 ∼2°C) were studied by laboratory simulation. The freeze-thaw treatment had no significant effect on microbial biomass nitrogen and the number of bacteria. The soil mineral N pool, the number of fungi, and enzyme activities were obviously affected by the freeze-thaw cycle. A mild freeze-thaw cycle (-2∼2°C) significantly increased the number of fungi and catalase activity, while severe freeze-thaw cycle (-20∼2°C) obviously decreased invertase activity. The results suggested that both the freeze-thaw rate and freeze-thaw temperature amplitudes have a strong effect on soil microbial dynamics in the alpine zone in winter. The results showed that exogenous carbon addition significantly decreased soil NO3-N and NH4 +-N contents, increased soil microbial biomass, the number of microbes, and soil enzyme activities. The results showed that microbial growth in the eastern Tibetan Plateau was somewhat limited by available C. It may represent a larger potential pulse of soil nutrient for alpine plants in the next spring, and may be instrumental for plant community shifts under future climate change predictions due to the possible increased litter addition.

  16. Simple additive simulation overestimates real influence: altered nitrogen and rainfall modulate the effect of warming on soil carbon fluxes.

    Science.gov (United States)

    Ni, Xiangyin; Yang, Wanqin; Qi, Zemin; Liao, Shu; Xu, Zhenfeng; Tan, Bo; Wang, Bin; Wu, Qinggui; Fu, Changkun; You, Chengming; Wu, Fuzhong

    2017-08-01

    Experiments and models have led to a consensus that there is positive feedback between carbon (C) fluxes and climate warming. However, the effect of warming may be altered by regional and global changes in nitrogen (N) and rainfall levels, but the current understanding is limited. Through synthesizing global data on soil C pool, input and loss from experiments simulating N deposition, drought and increased precipitation, we quantified the responses of soil C fluxes and equilibrium to the three single factors and their interactions with warming. We found that warming slightly increased the soil C input and loss by 5% and 9%, respectively, but had no significant effect on the soil C pool. Nitrogen deposition alone increased the soil C input (+20%), but the interaction of warming and N deposition greatly increased the soil C input by 49%. Drought alone decreased the soil C input by 17%, while the interaction of warming and drought decreased the soil C input to a greater extent (-22%). Increased precipitation stimulated the soil C input by 15%, but the interaction of warming and increased precipitation had no significant effect on the soil C input. However, the soil C loss was not significantly affected by any of the interactions, although it was constrained by drought (-18%). These results implied that the positive C fluxes-climate warming feedback was modulated by the changing N and rainfall regimes. Further, we found that the additive effects of [warming × N deposition] and [warming × drought] on the soil C input and of [warming × increased precipitation] on the soil C loss were greater than their interactions, suggesting that simple additive simulation using single-factor manipulations may overestimate the effects on soil C fluxes in the real world. Therefore, we propose that more multifactorial experiments should be considered in studying Earth systems. © 2016 John Wiley & Sons Ltd.

  17. Nitrapyrin addition mitigates nitrous oxide emissions and raises nitrogen use efficiency in plastic-film-mulched drip-fertigated cotton field.

    Science.gov (United States)

    Liu, Tao; Liang, Yongchao; Chu, Guixin

    2017-01-01

    Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted to evaluate the effect of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine) on soil mineral nitrogen (N) transformation, N2O emission and nitrogen use efficiency (NUE) in a drip-fertigated cotton-growing calcareous field. Three treatments were established: control (no N fertilizer), urea (225 kg N ha-1) and urea+nitrapyrin (225 kg N ha-1+2.25 kg nitrapyrin ha-1). Compared with urea alone, urea plus nitrapyrin decreased the average N2O emission fluxes by 6.6-21.8% in June, July and August significantly in a drip-fertigation cycle. Urea application increased the seasonal cumulative N2O emission by 2.4 kg N ha-1 compared with control, and nitrapyrin addition significantly mitigated the seasonal N2O emission by 14.3% compared with urea only. During the main growing season, the average soil ammonium nitrogen (NH4+-N) concentration was 28.0% greater and soil nitrate nitrogen (NO3--N) concentration was 13.8% less in the urea+nitrapyrin treatment than in the urea treatment. Soil NO3--N and water-filled pore space (WFPS) were more closely correlated than soil NH4+-N with soil N2O fluxes under drip-fertigated condition (Pemission factor (EF) by 32.4% while increasing nitrogen use efficiency by 10.7%. The results demonstrated that nitrapyrin addition significantly inhibited soil nitrification and maintained more NH4+-N in soil, mitigated N2O losses and improved nitrogen use efficiency in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition.

  18. Short-term Effect of Nitrogen Addition on Microbial and Root Respiration in an Alpine Spruce Ecosystem

    Directory of Open Access Journals (Sweden)

    Jian Wang1

    2017-03-01

    Full Text Available Soil respiration plays an important role in the carbon (C flux of the global C cycle and is greatly affected by nitrogen (N additions in the form of deposition or fertilization. The aim of this study was to investigate the response of total soil respiration (Rs, microbial respiration (Rm, and root respiration (Rr to short-term N addition and the potential mechanisms of short-term N deposition influencing soil respiration in an alpine spruce ecosystem. Four N treatment levels (0, 50, 100, 150 kg N ha-1 year-1 were applied monthly in a Picea balfouriana (commonly known as "alpine spruce" plantation beginning in November 2013 and Rs, Rm, and Rr were measured from May to November 2014. The results show that simulated N depositions stimulate Rs, Rm, and Rr and the beneficial effects decreased along N gradients from hourly to seasonal scales. The seasonal temperature coefficients (Q10 of Rs, Rm, and Rr ranged from 2.50 to 3.8, 2.99 to 4.63, and 1.86 to 2.96, while the diurnal Q10 ranged from 1.71 to 2.04, 1.89 to 2.32, 1.42 to 1.75, and there was a similar trend with soil respiration along N gradients. In addition, Rr showed significant positive correlation with fine root biomass, and Rm was likely driven by soil enzyme related to the microbial C cycle in the growing season. Our results indicate that short-term N addition stimulated fine root biomass and soil enzymatic activity to bring about a potential increase in soil respiration rates under low-N addition, while the opposite occurred under high-N addition.

  19. Short-term effect of nitrogen addition on nitric oxide emissions from an alpine meadow in the Tibetan Plateau.

    Science.gov (United States)

    Gao, Yongheng; Ma, Xingxing; Cooper, David J

    2016-06-01

    Little information is available on nitric oxide (NO) fluxes from alpine ecosystems. We measured NO fluxes in control and nitrogen (N) addition (NH4NO3, 6 g N m(-2) year(-1)) plots from early June through October 2013 in an alpine meadow on the Tibetan Plateau, China. During the sample period, NO fluxes varied from -0.71 to 3.12 ug m(-2) h(-1) and -0.46 to 7.54 ug m(-2) h(-1) for control and N treatment plots. The mean NO emission in N addition plots (1.68 ug m(-2) h(-1)) was 2.15 times higher than the control plots (0.78 ug m(-2) h(-1)), indicating that alpine meadows may be a source of atmospheric NO, and N additions stimulated NO flux. A positive correlation was found between NO flux and soil temperature, water-filled pore space (WFPS), nitrate (NO3 (-)-N) content but no correlation with soil ammonium (NH4 (+)-N). These results suggest that denitrification is a principal process producing NO flux from alpine meadows.

  20. Long-term N and P additions alter the scaling of plant nitrogen to phosphorus in a Tibetan alpine meadow.

    Science.gov (United States)

    Zhang, Juanjuan; Yan, Xuebin; Su, Fanglong; Li, Zhen; Wang, Ying; Wei, Yanan; Ji, Yangguang; Yang, Yi; Zhou, Xianhui; Guo, Hui; Hu, Shuijin

    2018-06-01

    Nitrogen and phosphorus are two important nutrient elements for plants. The current paradigm suggests that the scaling of plant tissue N to P is conserved across environments and plant taxa because these two elements are coupled and coordinately change with each other following a constant allometric trajectory. However, this assumption has not been vigorously examined, particularly in changing N and P environments. We propose that changes in relative availability of N and P in soil alter the N to P relationship in plants. Taking advantage of a 4-yr N and P addition experiment in a Tibetan alpine meadow, we examined changes in plant N and P concentrations of 14 common species. Our results showed that while the scaling of N to P under N additions was similar to the previously reported pattern with a uniform 2/3 slope of the regression between log N and log P, it was significantly different under P additions with a smaller slope. Also, graminoids had different responses from forbs. These results indicate that the relative availability of soil N and P is an important determinant regulating the N and P concentrations in plants. These findings suggest that alterations in the N to P relationships may not only alter plant photosynthate allocation to vegetative or reproductive organs, but also regulate the metabolic and growth rate of plant and promote shifts in plant community composition in a changing nutrient loading environment. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Myeloid-derived suppressor cells in murine AIDS inhibit B-cell responses in part via soluble mediators including reactive oxygen and nitrogen species, and TGF-β.

    Science.gov (United States)

    Rastad, Jessica L; Green, William R

    2016-12-01

    Monocytic myeloid-derived suppressor cells (M-MDSCs) were increased during LP-BM5 retroviral infection, and were capable of suppressing not only T-cell, but also B-cell responses. In addition to previously demonstrating iNOS- and VISTA-dependent M-MDSC mechanisms, in this paper, we detail how M-MDSCs utilized soluble mediators, including the reactive oxygen and nitrogen species superoxide, peroxynitrite, and nitric oxide, and TGF-β, to suppress B cells in a predominantly contact-independent manner. Suppression was independent of cysteine-depletion and hydrogen peroxide production. When two major mechanisms of suppression (iNOS and VISTA) were eliminated in double knockout mice, M-MDSCs from LP-BM5-infected mice were able to compensate using other, soluble mechanisms in order to maintain suppression of B cells. The IL-10 producing regulatory B-cell compartment was among the targets of M-MDSC-mediated suppression. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Green algal over cyanobacterial dominance promoted with nitrogen and phosphorus additions in a mesocosm study at Lake Taihu, China.

    Science.gov (United States)

    Ma, Jianrong; Qin, Boqiang; Paerl, Hans W; Brookes, Justin D; Wu, Pan; Zhou, Jian; Deng, Jianming; Guo, Jinsong; Li, Zhe

    2015-04-01

    Enrichment of waterways with nitrogen (N) and phosphorus (P) has accelerated eutrophication and promoted cyanobacterial blooms worldwide. An understanding of whether cyanobacteria maintain their dominance under accelerated eutrophication will help predict trends and provide rational control measures. A mesocosm experiment was conducted under natural light and temperature conditions in Lake Taihu, China. It revealed that only N added to lake water promoted growth of colonial and filamentous cyanobacteria (Microcystis, Pseudoanabaena and Planktothrix) and single-cell green algae (Cosmarium, Chlorella, and Scenedesmus). Adding P alone promoted neither cyanobacteria nor green algae significantly. N plus P additions promoted cyanobacteria and green algae growth greatly. The higher growth rates of green algae vs. cyanobacteria in N plus P additions resulted in the biomass of green algae exceeding that of cyanobacteria. This indicates that further enrichment with N plus P in eutrophic water will enhance green algae over cyanobacterial dominance. However, it does not mean that eutrophication problems will cease. On the contrary, the risk will increase due to increasing total phytoplankton biomass.

  3. Effect of nitrogen addition to ozone generation characteristics by diffuse and filamentary dielectric barrier discharges at atmospheric pressure

    Science.gov (United States)

    Osawa, Naoki; Tsuji, Takafumi; Ogiso, Ryota; Yoshioka, Yoshio

    2017-05-01

    Ozone is widely used for gas treatment, advanced oxidation processes, microorganisms inactivation, etc. In this research, we investigated the effect of nitrogen addition to ozone generation characteristics by atmospheric pressure Townsend discharge (APTD) type and filamentary dielectric barrier discharge (DBD) type ozone generators. The result showed that the ozone generated by the filamentary DBD increases rapidly with the increase of O2 content, and is higher than that by the APTD. On the other hand, it is interesting that the ozone generated by the APTD gradually decreases with the increase of O2 content. In order to clarify why the characteristics of ozone generation by the two kinds of discharge modes showed different dependency to the N2 content, we analyzed the exhaust gas composition using FTIR spectroscopy and calculated the rate coefficients using BOLSIG+ code. As a result, we found that although O2 content decreased with increasing N2 content, additional O atoms produced by excited N2 molecules contribute to ozone generation in case of APTD. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  4. Physiological Responses of Two Epiphytic Bryophytes to Nitrogen, Phosphorus and Sulfur Addition in a Subtropical Montane Cloud Forest.

    Science.gov (United States)

    Chen, Xi; Liu, Wen-Yao; Song, Liang; Li, Su; Wu, Yi; Shi, Xian-Meng; Huang, Jun-Biao; Wu, Chuan-Sheng

    2016-01-01

    Atmospheric depositions pose significant threats to biodiversity and ecosystem function. However, the underlying physiological mechanisms are not well understood, and few studies have considered the combined effects and interactions of multiple pollutants. This in situ study explored the physiological responses of two epiphytic bryophytes to combined addition of nitrogen, phosphorus and sulfur. We investigated the electrical conductivity (EC), total chlorophyll concentration (Chl), nutrient stoichiometry and chlorophyll fluorescence signals in a subtropical montane cloud forest in south-west China. The results showed that enhanced fertilizer additions imposed detrimental effects on bryophytes, and the combined enrichment of simulated fertilization exerted limited synergistic effects in their natural environments. On the whole, EC, Chl, the effective quantum yield of photosystem II (ΦPSII) and photochemical quenching (qP) were the more reliable indicators of increased artificial fertilization. However, conclusions on nutrient stoichiometry should be drawn cautiously concerning the saturation uptake and nutrient interactions in bryophytes. Finally, we discuss the limitations of prevailing fertilization experiments and emphasize the importance of long-term data available for future investigations.

  5. Effects of Nitrogen Addition on the Drought Susceptibility of the Leymus chinensis Meadow Ecosystem Vary with Drought Duration

    Directory of Open Access Journals (Sweden)

    Baoku Shi

    2018-02-01

    Full Text Available It is not clear yet how extreme drought and nitrogen (N deposition influence grassland ecosystem functions when they are considered together, especially in complex field conditions. To explore the response of the Leymus chinensis meadow ecosystem to manipulated extreme drought (45 days, N addition and their interaction, we measured leaf photosynthetic characteristics, aboveground phytomass on the community level and ecosystem C exchange in different treatments at the middle and the end of the drought period. The extreme drought treatment decreased the leaf net CO2 assimilation rate and ecosystem C exchange [gross ecosystem productivity (GEP, ecosystem respiration and net ecosystem CO2 exchange]. In contrast, the N addition treatment increased aboveground phytomass, GEP and net ecosystem CO2 exchange. The effects of N addition on the drought susceptibility of the L. chinensis meadow ecosystem varied with drought severity. The N addition treatment alleviated drought-induced suppression of CO2 exchange at the leaf and ecosystem levels in the middle of the drought period, whereas it exacerbated drought-induced suppression of the CO2 exchange and aboveground phytomass on the community level at the end of the drought period. Given that dominance by L. chinensis is a characteristic of the studied ecosystem, knowledge of the traits of L. chinensis and its response to multiple global change drivers will be crucial for predicting future ecosystem functions. Furthermore, increasing N deposition may affect the response of the L. chinensis meadow ecosystem to further droughts by increasing carbon allocation to roots and therefore root–shoot ratios.

  6. Effects of Nitrogen Addition on Leaf Decomposition of Single-Species and Litter Mixture in Pinus tabulaeformis Forests

    Directory of Open Access Journals (Sweden)

    Jinsong Wang

    2015-12-01

    Full Text Available The litter decomposition process is closely correlated with nutrient cycling and the maintenance of soil fertility in the forest ecosystem. In particular, the intense environmental concern about atmospheric nitrogen (N deposition requires a better understanding of its influence on the litter decomposition process. This study examines the responses of single-species litter and litter mixture decomposition processes to N addition in Chinese pine (Pinus tabulaeformis Carr. ecosystems. Chinese pine litter, Mongolian oak (Quercus mongolica Fisch. ex Ledeb. litter, and a pine–oak mixture were selected from a plantation and a natural forest of Chinese pine. Four N addition treatments, i.e., control (N0: 0 kg N ha−1·year−1, low-N (N1: 5 kg N ha−1·year−1, medium-N (N2: 10 kg N ha−1·year−1, and high-N (N3: 15 kg N ha−1·year−1, were applied starting May 2010. In the plantation, N addition significantly stimulated the decomposition of the Chinese pine litter. In the natural forest, N addition had variable effects on the decomposition of single-species litter and the litter mixture. A stimulatory effect of the high-N treatment on the Chinese pine litter decomposition could be attributed to a decrease in the substrate C:N ratio. However, an opposite effect was found for the Mongolian oak litter decomposition. The stimulating effect of N addition on the Chinese pine litter may offset the suppressive effect on the Mongolian oak litter, resulting in a neutral effect on the litter mixture. These results suggest that the different responses in decomposition of single-species litter and the litter mixture to N addition are mainly attributed to litter chemical composition. Further investigations are required to characterize the effect of long-term high-level N addition on the litter decomposition as N deposition is likely to increase rapidly in the region where this study was conducted.

  7. Members of the LBD family of transcription factors repress anthocyanin synthesis and affect additional nitrogen responses in Arabidopsis.

    Science.gov (United States)

    Rubin, Grit; Tohge, Takayuki; Matsuda, Fumio; Saito, Kazuki; Scheible, Wolf-Rüdiger

    2009-11-01

    Nitrogen (N) and nitrate (NO(3)(-)) per se regulate many aspects of plant metabolism, growth, and development. N/NO(3)(-) also suppresses parts of secondary metabolism, including anthocyanin synthesis. Molecular components for this repression are unknown. We report that three N/NO(3)(-)-induced members of the LATERAL ORGAN BOUNDARY DOMAIN (LBD) gene family of transcription factors (LBD37, LBD38, and LBD39) act as negative regulators of anthocyanin biosynthesis in Arabidopsis thaliana. Overexpression of each of the three genes in the absence of N/NO(3)(-) strongly suppresses the key regulators of anthocyanin synthesis PAP1 and PAP2, genes in the anthocyanin-specific part of flavonoid synthesis, as well as cyanidin- but not quercetin- or kaempferol-glycoside production. Conversely, lbd37, lbd38, or lbd39 mutants accumulate anthocyanins when grown in N/NO(3)(-)-sufficient conditions and show constitutive expression of anthocyanin biosynthetic genes. The LBD genes also repress many other known N-responsive genes, including key genes required for NO(3)(-) uptake and assimilation, resulting in altered NO(3)(-) content, nitrate reductase activity/activation, protein, amino acid, and starch levels, and N-related growth phenotypes. The results identify LBD37 and its two close homologs as novel repressors of anthocyanin biosynthesis and N availability signals in general. They also show that, besides being developmental regulators, LBD genes fulfill roles in metabolic regulation.

  8. Soil bacterial and fungal community responses to nitrogen addition across soil depth and microhabitat in an arid shrubland

    Science.gov (United States)

    Mueller, Rebecca C.; Belnap, Jayne; Kuske, Cheryl R.

    2015-01-01

    Arid shrublands are stressful environments, typified by alkaline soils low in organic matter, with biologically-limiting extremes in water availability, temperature, and UV radiation. The widely-spaced plants and interspace biological soil crusts in these regions provide soil nutrients in a localized fashion, creating a mosaic pattern of plant- or crust-associated microhabitats with distinct nutrient composition. With sporadic and limited rainfall, nutrients are primarily retained in the shallow surface soil, patterning biological activity. We examined soil bacterial and fungal community responses to simulated nitrogen (N) deposition in an arid Larrea tridentata-Ambrosia dumosa field experiment in southern Nevada, USA, using high-throughput sequencing of ribosomal RNA genes. To examine potential interactions among the N application, microhabitat and soil depth, we sampled soils associated with shrub canopies and interspace biological crusts at two soil depths (0–0.5 or 0–10 cm) across the N-amendment gradient (0, 7, and 15 kg ha−1 yr−1). We hypothesized that localized compositional differences in soil microbiota would constrain the impacts of N addition to a microhabitat distribution that would reflect highly localized geochemical conditions and microbial community composition. The richness and community composition of both bacterial and fungal communities differed significantly by microhabitat and with soil depth in each microhabitat. Only bacterial communities exhibited significant responses to the N addition. Community composition correlated with microhabitat and depth differences in soil geochemical features. Given the distinct roles of soil bacteria and fungi in major nutrient cycles, the resilience of fungi and sensitivity of bacteria to N amendments suggests that increased N input predicted for many arid ecosystems could shift nutrient cycling toward pathways driven primarily by fungal communities.

  9. Soil bacterial and fungal community responses to nitrogen addition across soil depths and microhabitat in an arid shrubland

    Directory of Open Access Journals (Sweden)

    Rebecca C Mueller

    2015-09-01

    Full Text Available Arid shrublands are stressful environments, typified by alkaline soils low in organic matter, with biologically-limiting extremes in water availability, temperature and UV radiation. The widely-spaced plants and interspace biological soil crusts in these regions provide soil nutrients in a localized fashion, creating a mosaic pattern of plant- or crust-associated microhabitats with distinct nutrient composition. With sporadic and limited rainfall, nutrients are primarily retained in the shallow surface soil, patterning biological activity. We examined soil bacterial and fungal community responses to simulated nitrogen (N deposition in an arid Larrea tridentata-Ambrosia dumosa field experiment in southern Nevada, USA, using high-throughput sequencing of ribosomal RNA genes. To examine potential interactions among the N application, microhabitat and soil depth, we sampled soils associated with shrub canopies and interspace biological crusts at two soil depths (0-0.5 cm or 0-10 cm across the N-amendment gradient (0, 7 and 15 kg ha-1 yr-1. We hypothesized that localized compositional differences in soil microbiota would constrain the impacts of N addition to a microhabitat distribution that would reflect highly localized geochemical conditions and microbial community composition. The richness and community composition of both bacterial and fungal communities differed significantly by microhabitat and with soil depth in each microhabitat. Only bacterial communities exhibited significant responses to the N addition. Community composition correlated with microhabitat and depth differences in soil geochemical features. Given the distinct roles of soil bacteria and fungi in major nutrient cycles, the resilience of fungi and sensitivity of bacteria to N amendments suggests that increased N input predicted for many arid ecosystems could shift nutrient cycling toward pathways driven primarily by fungal communities.

  10. Uranium hydrogeochemical and stream sediment reconnaissance of the Pueblo NTMS quadrangel, Colorado, including concentrations of forty-three additional elements

    International Nuclear Information System (INIS)

    Shannon, S.S. Jr.

    1978-12-01

    This report is a supplement to the HSSR uranium evaluation report for the Pueblo quadrangle (Shannon, 1978), which presented the field and uranium data for the 861 water and 1060 sediment samples collected from 1402 locations in the quadrangle. This supplement presents those data again and the results of subsequent multielement analyses of those HSSR samples. In addition to uranium, the concentrations of 12 elements are presented for the waters and 42 elements for the sediments

  11. Effect of climate change, CO2 trends, nitrogen addition, and land-cover and management intensity changes on the carbon balance of European grasslands.

    Science.gov (United States)

    Chang, Jinfeng; Ciais, Philippe; Viovy, Nicolas; Vuichard, Nicolas; Herrero, Mario; Havlík, Petr; Wang, Xuhui; Sultan, Benjamin; Soussana, Jean-François

    2016-01-01

    Several lines of evidence point to European managed grassland ecosystems being a sink of carbon. In this study, we apply ORCHIDEE-GM a process-based carbon cycle model that describes specific management practices of pastures and the dynamics of carbon cycling in response to changes in climatic and biogeochemical drivers. The model is used to simulate changes in the carbon balance [i.e., net biome production (NBP)] of European grasslands over 1991-2010 on a 25 km × 25 km grid. The modeled average trend in NBP is 1.8-2.0 g C m(-2)  yr(-2) during the past two decades. Attribution of this trend suggests management intensity as the dominant driver explaining NBP trends in the model (36-43% of the trend due to all drivers). A major change in grassland management intensity has occurred across Europe resulting from reduced livestock numbers. This change has 'inadvertently' enhanced soil C sequestration and reduced N2 O and CH4 emissions by 1.2-1.5 Gt CO2 -equivalent, offsetting more than 7% of greenhouse gas emissions in the whole European agricultural sector during the period 1991-2010. Land-cover change, climate change and rising CO2 also make positive and moderate contributions to the NBP trend (between 24% and 31% of the trend due to all drivers). Changes in nitrogen addition (including fertilization and atmospheric deposition) are found to have only marginal net effect on NBP trends. However, this may not reflect reality because our model has only a very simple parameterization of nitrogen effects on photosynthesis. The sum of NBP trends from each driver is larger than the trend obtained when all drivers are varied together, leaving a residual - nonattributed - term (22-26% of the trend due to all drivers) indicating negative interactions between drivers. © 2015 John Wiley & Sons Ltd.

  12. Method for assessment of stormwater treatment facilities – Synthetic road runoff addition including micro-pollutants and tracer

    DEFF Research Database (Denmark)

    Cederkvist, Karin; Jensen, Marina Bergen; Holm, Peter Engelund

    2017-01-01

    % in the dual porosity filter, stressing the importance of including a conservative tracer for correction of contaminant retention values. The method is considered useful in future treatment performance testing of STFs. The observed performance of the STFs is presented in coming papers.......Stormwater treatment facilities (STFs) are becoming increasingly widespread but knowledge on their performance is limited. This is due to difficulties in obtaining representative samples during storm events and documenting removal of the broad range of contaminants found in stormwater runoff...

  13. How nitrogen and sulphur addition, and a single drought event affect root phosphatase activity in Phalaris arundinacea

    NARCIS (Netherlands)

    Robroek, B.J.M.; Adema, E.B.; Venterink, H.O.; Leonardson, L.; Wassen, M.J.

    2009-01-01

    Conservation and restoration of fens and fen meadows often aim to reduce soil nutrients, mainly nitrogen (N) andphosphorus (P). The biogeochemistry of P has received much attention as P-enrichment is expected to negatively impact on species diversity in wetlands. It is known that N, sulphur (S) and

  14. Analysis of nitrogen cycling in a forest stream during autumn using a 15N-tracer addition

    Science.gov (United States)

    Jennifer L. Tank; Judy L. Meyer; Diane M. Sanzone; Patrick J. Mulholland; Jackson R. Webster; Bruce J. Peterson; Wilfred M. Wollheim; Norman E. Leonard

    2000-01-01

    We added l5NH4Cl over 6 weeks to Upper Ball Creek, a second-order deciduous forest stream in the Appalachian Mountains, to follow the uptake, spiraling, and fate of nitrogen in a stream food web during autumn. A priori predictions of N flow and retention were made using a simple food web mass balance model. Values of ...

  15. Effect of nitrogen addition and drought on above-ground biomass of expanding tall grasses Calamagrostis epigejos and Arrhenatherum elatius

    Czech Academy of Sciences Publication Activity Database

    Fiala, Karel; Tůma, Ivan; Holub, Petr

    2011-01-01

    Roč. 66, č. 2 (2011), s. 275-281 ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA526/06/0556 Institutional research plan: CEZ:AV0Z60050516 Keywords : nitrogen * drought * above-ground biomass Subject RIV: EF - Botanics Impact factor: 0.557, year: 2011

  16. Fatigue Behavior and Modeling of Additively Manufactured Ti-6Al-4V Including Interlayer Time Interval Effects

    Science.gov (United States)

    Torries, Brian; Shamsaei, Nima

    2017-12-01

    The effects of different cooling rates, as achieved by varying the interlayer time interval, on the fatigue behavior of additively manufactured Ti-6Al-4V specimens were investigated and modeled via a microstructure-sensitive fatigue model. Comparisons are made between two sets of specimens fabricated via Laser Engineered Net Shaping (LENS™), with variance in interlayer time interval accomplished by depositing either one or two specimens per print operation. Fully reversed, strain-controlled fatigue tests were conducted, with fractography following specimen failure. A microstructure-sensitive fatigue model was calibrated to model the fatigue behavior of both sets of specimens and was found to be capable of correctly predicting the longer fatigue lives of the single-built specimens and the reduced scatter of the double-built specimens; all data points fell within the predicted upper and lower bounds of fatigue life. The time interval effects and the ability to be modeled are important to consider when producing test specimens that are smaller than the production part (i.e., property-performance relationships).

  17. Uranium hydrogeochemical and stream sediment reconnaissance of the Arminto NTMS quadrangle, Wyoming, including concentrations of forty-three additional elements

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, T.L.

    1979-11-01

    During the summers of 1976 and 1977, 570 water and 1249 sediment samples were collected from 1517 locations within the 18,000-km/sup 2/ area of the Arminto NTMS quadrangle of central Wyoming. Water samples were collected from wells, springs, streams, and artifical ponds; sediment samples were collected from wet and dry streams, springs, and wet and dry ponds. All water samples were analyzed for 13 elements, including uranium, and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit to 84.60 parts per billion (ppb) with a mean of 4.32 ppb. All water sample types except pond water samples were considered as a single population in interpreting the data. Pond water samples were excluded due to possible concentration of uranium by evaporation. Most of the water samples containing greater than 20 ppb uranium grouped into six clusters that indicate possible areas of interest for further investigation. One cluster is associated with the Pumpkin Buttes District, and two others are near the Kaycee and Mayoworth areas of uranium mineralization. The largest cluster is located on the west side of the Powder River Basin. One cluster is located in the central Big Horn Basin and another is in the Wind River Basin; both are in areas underlain by favorable host units. Uranium concentrations in sediment samples range from 0.08 parts per million (ppm) to 115.50 ppm with a mean of 3.50 ppm. Two clusters of sediment samples over 7 ppm were delineated. The first, containing the two highest-concentration samples, corresponds with the Copper Mountain District. Many of the high uranium concentrations in samples in this cluster may be due to contamination from mining or prospecting activity upstream from the sample sites. The second cluster encompasses a wide area in the Wind River Basin along the southern boundary of the quadrangle.

  18. 40 CFR Table 2 to Subpart Cb of... - Nitrogen Oxides Limits for Existing Designated Facilities Included in an Emissions Averaging Plan...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Nitrogen Oxides Limits for Existing.... 60, Subpt. Cb, Table 2 Table 2 to Subpart Cb of Part 60—Nitrogen Oxides Limits for Existing... by volume) b On and after April 28, 2009, nitrogen oxides emission limit (parts permillion by volume...

  19. Uranium hydrogeochemical and stream sediment reconnaissance of the Gillette NTMS quadrangle, Wyoming, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Warren, R.G.; George, W.E.; Minor, M.M.; Simi, O.R.; Talcott, C.L.; Hensley, W.K.; Cheadle, J.M. III.

    1980-08-01

    During 1976 and 1977, 752 water and 843 sediment samples were collected from 1419 locations within the 17 700-km 2 area of the Gillette quadrangle, Wyoming. Water samples were collected primarily from wells, and also from springs, ponds, and streams; sediment samples were collected primarily from stream channels, and also from springs and ponds. Each water sample was analyzed for uranium and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit of 0.02 to 212.20 ppB and have a median of 1.10 ppB. The highest background uranium concentrations, as well as the highest individual uranium values, are in areas where favorable host units for uranium mineralization crop out. These units are the Wasatch and Fort Union formations in the Powder River Basin and the Inyan Kara group in the Black Hills. Uranium concentrations in sediment samples range from 0.64 to 29.83 ppM and have a median of 3.24 ppM. Background uranium concentrations are strongly controlled by the exposed geologic unit, and range from 4 to 8 ppM for the Cretaceous Colorado group to 1 to 3 ppM for the Triassic and Paleozoic units exposed in the Black Hills. Several areas where the Wasatch and Fort Union formations are exposed exhibit uranium concentrations in sediment samples that are slightly, but distinctly, above background values for these units. All of these areas are also associated with notably high uranium concentrations in water samples. Because epigenetic uranium mineralization in economically important areas can exhibit a similar geochemical signature, these areas within the Gillette quadrangle should be further examined for the possible presence of uranium mineralization

  20. Uranium hydrogeochemical and stream sediment reconnaissance of the Newcastle NTMS Quadrangle, Wyoming, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Goff, S.J.; Sandoval, W.F.; Gallimore, D.L.; Talcott, C.L.; Martinez, R.G.; Minor, M.E.; Mills, C.F.

    1980-06-01

    Water and sediment samples were collected and each water sample was analyzed for U, and each sediment sample was analyzed for 43 elements, including U and Th. Uranium concentrations in water samples range from below the detection limit of 0.02 ppB to 702.26 ppB and have a median of 1.73 ppB and a mean of 11.76 ppB. Water samples containing high uranium concentrations generally are associated with known uranium mining activity or units known to be uranium bearing. About one-third of the water samples containing high uranium concentrations were collected from locations within the Pumpkin Buttes and Turnercrest-Ross Districts. Nearly half of the water samples containing high uranium concentrations were collected from locations just west of the Monument Hill and Highland Flats-Box Creek Districts. Similar anomalous uranium concentrations in this region have been reported updip from Exxon's Highland uranium deposits. High uranium concentrations were also found associated with the Lance Creek-Old Woman Anticline District. Uranium concentrations in sediment samples range from 1.14 to 220.70 ppM and have a median of 3.37 ppM and a mean of 4.03 ppM. Throughout the major uranium mining districts of the Powder River Basin, sediment samples with high uranium concentrations were collected from dry streams located near wells producing water samples with high uranium concentrations. High uranium concentrations were also found associated with the Lance Creek oil field where uranium mineralization is known in the White River formation. High uranium concentrations were also found in sediment samples in areas where uranium mineralization is not known. These samples are from dry streams in areas underlain by the White River formation, the Niobrara formation, and the Pierre, Carlisle, Belle Fourche, and Mowry shales

  1. Impact of the addition of different plant residues on carbon-nitrogen content and nitrogen mineralization-immobilization turnover in a soil incubated under laboratory conditions

    Science.gov (United States)

    Abbasi, M. K.; Tahir, M. M.; Sabir, N.; Khurshid, M.

    2014-10-01

    Application of plant residues as soil amendment may represent a valuable recycling strategy that affects on carbon (C) and nitrogen (N) cycling, soil properties improvement and plant growth promotion. The amount and rate of nutrient release from plant residues depend on their quality characteristics and biochemical composition. A laboratory incubation experiment was conducted for 120 days under controlled conditions (25 °C and 58% water filled pore space (WFPS)) to quantify initial biochemical composition and N mineralization of leguminous and non-leguminous plant residues i.e. the roots, shoots and leaves of Glycine max, Trifolium repens, Zea mays, Poplus euramericana, Rubinia pseudoacacia and Elagnus umbellate incorporated into the soil at the rate of 200 mg residue N kg-1 soil. The diverse plant residues showed wide variation in total N, carbon, lignin, polyphenols and C/N ratio with higher polyphenol content in the leaves and higher lignin content in the roots. The shoot of G. max and the shoot and root of T. repens displayed continuous mineralization by releasing a maximum of 109.8, 74.8 and 72.5 mg N kg-1 and representing a 55, 37 and 36% of added N being released from these resources. The roots of G. max and Z. mays and the shoot of Z. mays showed continuous negative values throughout the incubation showing net immobilization. After an initial immobilization, leaves of P. euramericana, R. pseudoacacia and E. umbellate exhibited net mineralization by releasing a maximum of 31.8, 63.1 and 65.1 mg N kg-1, respectively and representing a 16, 32 and 33% of added N being released. Nitrogen mineralization from all the treatments was positively correlated with the initial residue N contents (r = 0.89; p ≤ 0.01), and negatively correlated with lignin content (r = -0.84; p ≤ 0.01), C/N ratio (r = -0.69; p ≤ 0.05), lignin/N ratio (r = -0.68; p ≤ 0.05), polyphenol/N ratio (r = -0.73; p ≤ 0.05) and ligin + polyphenol/N ratio (r = -0.70; p ≤ 0.05) indicating

  2. EFFECTS OF PROTEIN-XANTHOPHYLL (PX CONCENTRATE OF ALFALFA ADDITIVE TO CRUDE PROTEIN-REDUCED DIETS ON NITROGEN EXCRETION, GROWTH PERFORMANCE AND MEAT QUALITY OF PIGS

    Directory of Open Access Journals (Sweden)

    Eugeniusz GRELA

    2009-06-01

    Full Text Available The infl uence of protein-xanthophyll (PX concentrate of alfalfa supplement to crude protein-reduced diets was examined in relation to nitrogen excretion, performance parameters and pig meat quality. The investigations included 60 growers (PL x PLW x Duroc crossbreeds assigned to 3 groups. The conclusion is that there is a large potential to decrease nitrogen emission to the environment by 10% lowering of dietary crude protein intake along with reduced animal growth rate and elevated mixture utilization. Inclusion of a protein-xanthophyll concentrate (PX of alfalfa to the diet is likely to diminish disadvantageous productive parameters arising from limiting of total crude protein level in relation to the requirements of pigs feeding norms [1993]. At the same time, it improves feed nitrogen utilization and reduces noxious odour emissions from a piggery. The components of a protein-xanthophyll concentrate (PX contribute to increased liver and kidney weight.

  3. Linking Changes to Intraspecific Trait Diversity to Community Functional Diversity and Biomass in Response to Snow and Nitrogen Addition Within an Inner Mongolian Grassland.

    Science.gov (United States)

    Mao, Wei; Felton, Andrew J; Zhang, Tonghui

    2017-01-01

    In recent years, both the intraspecific and interspecific functional diversity (FD) of plant communities have been studied with new approaches to improve an understanding about the mechanisms underlying plant species coexistence. Yet, little is known about how global change drivers will impact intraspecific FD and trait overlap among species, and in particular how this may scale to impacts on community level FD and ecosystem functioning. To address this uncertainty, we assessed the direct and indirect responses of specific leaf area (SLA) among both dominant annual and subordinate perennial species to the independent and interactive effects of nitrogen and snow addition within the Inner Mongnolian steppe. More specifically, we investigated the consequences for these responses on plant community FD, trait overlap and biomass. Nitrogen addition increased the biomass of the dominant annual species and as a result increased total community biomass. This occurred despite concurrent decreases in the biomass of subordinate perennial species. Nitrogen addition also increased intraspecific FD and trait overlap of both annual species and perennial species, and consequently increased the degree of trait overlap in SLA at the community level. However, snow addition did not significantly impact intraspecific FD and trait overlap of SLA for perennial species, but increased intraspecific FD and trait overlap of annual species, of which scaled to changes in community level FD. We found that the responses of the dominant annual species to nitrogen and snow additions were generally more sensitive than the subordinate perennial species within the inner Mongolian grassland communities of our study. As a consequence of this sensitivity, the responses of the dominant species largely drove impacts to community FD, trait overlap and community biomass. In total, our study demonstrates that the responses of dominant species in a community to environmental change may drive the initial

  4. The Response of Nannochloropsis gaditana to Nitrogen Starvation Includes De Novo Biosynthesis of Triacylglycerols, a Decrease of Chloroplast Galactolipids, and Reorganization of the Photosynthetic Apparatus

    Science.gov (United States)

    Simionato, Diana; Block, Maryse A.; La Rocca, Nicoletta; Jouhet, Juliette; Maréchal, Eric

    2013-01-01

    Microalgae of the genus Nannochloropsis are capable of accumulating triacylglycerols (TAGs) when exposed to nutrient limitation (in particular, nitrogen [N]) and are therefore considered promising organisms for biodiesel production. Here, after nitrogen removal from the medium, Nannochloropsis gaditana cells showed extensive triacylglycerol accumulation (38% TAG on a dry weight basis). Triacylglycerols accumulated during N deprivation harbored signatures, indicating that they mainly stemmed from freshly synthesized fatty acids, with a small proportion originating from a recycling of membrane glycerolipids. The amount of chloroplast galactoglycerolipids, which are essential for the integrity of thylakoids, decreased, while their fatty acid composition appeared to be unaltered. In starved cells, galactolipids were kept at a level sufficient to maintain chloroplast integrity, as confirmed by electron microscopy. Consistently, N-starved Nannochloropsis cells contained less photosynthetic membranes but were still efficiently performing photosynthesis. N starvation led to a modification of the photosynthetic apparatus with a change in pigment composition and a decrease in the content of all the major electron flow complexes, including photosystem II, photosystem I, and the cytochrome b6f complex. The photosystem II content was particularly affected, leading to the inhibition of linear electron flow from water to CO2. Such a reduction, however, was partially compensated for by activation of alternative electron pathways, such as cyclic electron transport. Overall, these changes allowed cells to modify their energetic metabolism in order to maintain photosynthetic growth. PMID:23457191

  5. Influence of small additives of nitrogen in 1D-modeling of non-uniform microwave discharge of low pressure in hydrogen

    Science.gov (United States)

    Lebedev, Yu A.; Tatarinov, A. V.; Epstein, I. L.

    2017-11-01

    A one-dimensional simulation for studying the influence of small additives of nitrogen to the parameters and structure of non-uniform microwave discharge in hydrogen at pressure of 1 Torr has been performed. It is shown that the profiles of the electron density and microwave field are affected by changes both in the EEDF and in the ionic constituent of the plasma. The EEDF influences in a spherical region of the discharge (away from the central electrode). The addition of nitrogen increases the mobility of electrons and leads to reduction of size of the plasma formation. The change in the ion components of plasma (N2H+ becomes the main ion) affects the structure of the plasma near the surface of the electrode.

  6. Effects of pyrolysis temperature, time and leaf litter and powder coal ash addition on sludge-derived adsorbents for nitrogen oxide.

    Science.gov (United States)

    Ren, Xiaoli; Liang, Baohong; Liu, Min; Xu, Xiaoyuan; Cui, Meihua

    2012-12-01

    The objective of this research was to seek a cost effective solution to prepare adsorbents for nitrogen oxide from surplus sludge. Leaf litter and powder coal ash were used as cheap and easily available additives. An adsorbent for nitrogen oxide was prepared by pyrolysis of dried sludge mixed with zinc chloride. Under optimum pyrolysis conditions of 375°C for 90 min and a zinc chloride content of 30%, the surface area of the adsorbent with leaf litter was 514.41 m(2)/g, the surface area of the adsorbent with powder coal ash was 432.34 m(2)/g, respectively, corresponding to an increase of 90.70% and 60.27% when compared to the adsorbent without the additives. The saturated adsorption quantity of the adsorbent with leaf litter reached 271 mg/g at 20°C. The results indicated that the sludge-derived adsorbent was quite promising for nitrogen oxide removal. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Impact of warming, moderate nitrogen addition and bark herbivory on BVOC emissions and growth of Scots pine (Pinus sylvestris L.) seedlings.

    Science.gov (United States)

    Tiiva, Päivi; Häikiö, Elina; Kasurinen, Anne

    2018-04-10

    The changing climate will expose boreal forests to rising temperatures, increasing soil nitrogen (N) levels and an increasing risk of herbivory. The single and interaction effects of warming (+2 °C increase), moderate N addition (30 kg ha-1 year-1) and bark herbivory by large pine weevil (Hylobius abietis L.) on growth and emissions of biogenic volatile organic compounds (BVOCs) from shoots of Scots pine (Pinus sylvestris L.) seedlings were studied in growth chambers over 175 days. In addition, warming and N addition effects on shoot net photosynthesis (Pn) were measured. Nitrogen addition increased both shoot and root dry weights, whereas warming, in combination with herbivory, reduced stem height growth. Warming together with N addition increased current-year shoot Pn, whereas N effects on previous-year shoot Pn were variable over time. Warming decreased non-oxygenated monoterpene (MT) emissions in June and increased them in July. Of individual MT compounds, α-pinene, δ-3-carene, γ-terpinene and terpinolene were among the most frequently responsive compounds in warming treatments in the May-July period. Sesquiterpene emissions were observed only from warming treatments in July. Moderate N addition increased oxygenated monoterpenes in May, and MTs in June and September. However, N addition effect on MTs in June was clearer without warming than with warming. Bark herbivory tended to increase MT emissions in combination with warming and N addition 3 weeks after the damage caused by weevils. Of individual compounds in other BVOC blends, herbivory increased the emissions of methyl-benzene, benzene and hexanal in July. Hence, though both warming and N addition have a potential to change BVOC emissions from Scots pines, the N effect may also be partly cancelled by warming. Furthermore, herbivory pressure in combination with climate warming and N addition may, at least periodically, increase BVOC release to the atmosphere from young Scots pine seedlings.

  8. Synthesis, Characterization, and Tribological Evaluation of TiO2-Reinforced Boron and Nitrogen co-Doped Reduced Graphene Oxide Based Hybrid Nanomaterials as Efficient Antiwear Lubricant Additives.

    Science.gov (United States)

    Jaiswal, Vinay; Kalyani; Umrao, Sima; Rastogi, Rashmi B; Kumar, Rajesh; Srivastava, Anchal

    2016-05-11

    The microwave-synthesized reduced graphene oxide (MRG), boron-doped reduced graphene oxide (B-MRG), nitrogen-doped reduced graphene oxide (N-MRG), boron-nitrogen-co-doped reduced graphene oxide (B-N-MRG), and TiO2-reinforced B-N-MRG (TiO2-B-N-MRG) nanomaterials have been synthesized and characterized by various state-of-the-art techniques, like Raman spectroscopy, powder X-ray diffraction, scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Furthermore, the tribological properties of prepared nanomaterials as antiwear additives in neutral paraffin oil have been evaluated using a four-ball machine at an optimized additive concentration (0.15% w/v). The tribological parameters, like mean wear scar diameter, coefficient of friction, and wear rates, revealed that these nanomaterials have potential to be developed as environmentally friendly sulfated-ash-, phosphorus-, and sulfur-free antiwear lubricant additives. The friction- and wear-reducing behavior of MRG increased upon successive doping of nitrogen, boron, and both nitrogen and boron. Among these additives, B-N-co-doped MRG shows superior tribological behavior in paraffin base oil. Besides this, the load-carrying properties of B-N-co-doped MRG have significantly improved after its reinforcement with TiO2 nanoparticles. A comparative study of the surface morphology of a lubricated track in the presence of various additives has been assessed by SEM and contact-mode atomic force microscopy. The X-ray photoelectron spectroscopy studies have proved that the excellent lubrication properties of TiO2-B-N-MRG are due to the in situ formation of a tribofilm composed of boron nitride, adsorbed graphene layers, and tribosintered TiO2 nanoparticles during the tribocontact. Being sulfur-, halogen-, and phosphorus-free, these graphene-based nanomaterials act as green antiwear additives, protecting interacting

  9. Influence of the nitrogen gas addition in the Ar shielding gas on the erosion-corrosion of tube-to-tube sheet welds of hyper duplex stainless steel

    International Nuclear Information System (INIS)

    Kim, Hye-Jin; Jeon, Soon-Hyeok; Kim, Soon-Tae; Lee, In-Sung; Park, Yong-Soo

    2014-01-01

    Duplex stainless steels with nearly equal fraction of the ferrite(α) phase and austenite(γ) phase have been increasingly used for various applications such as power plants, desalination facilities due to their high resistance to corrosion, good weldability, and excellent mechanical properties. Hyper duplex stainless steel (HDSS) is defined as the future duplex stainless steel with a pitting resistance equivalent (PRE= wt.%Cr+3.3(wt.%Mo+0.5wt.%W)+30wt.%N) of above 50. However, when HDSS is welded with gas tungsten arc (GTA), incorporation of nitrogen in the Ar shielding gas are very important because the volume fraction of α-phase and γ-phase is changed and harmful secondary phases can be formed in the welded zone. In other words, the balance of corrosion resistance between two phases and reduction of Cr 2 N are the key points of this study. The primary results of this study are as follows. The addition of N 2 to the Ar shielding gas provides phase balance under weld-cooling conditions and increases the transformation temperature of the α-phase to γ-phase, increasing the fraction of γ-phase as well as decreasing the precipitation of Cr2N. In the anodic polarization test, the addition of nitrogen gas in the Ar shielding gas improved values of the electrochemical parameters, compared to the Pure Ar. Also, in the erosion-corrosion test, the HDSS welded with shielding gas containing N 2 decreased the weight loss, compared to HDSS welded with the Ar pure gas. This result showed the resistance of erosion-corrosion was increased due to increasing the fraction of γ-phase and the stability of passive film according to the addition N 2 gas to the Ar shielding gas. As a result, the addition of nitrogen gas to the shielding gas improved the resistance of erosion-corrosion

  10. Effects of nitrogen addition on soil microbes and their implications for soil C emission in the Gurbantunggut Desert, center of the Eurasian Continent.

    Science.gov (United States)

    Huang, Gang; Cao, Yan Feng; Wang, Bin; Li, Yan

    2015-05-15

    Nitrogen (N) deposition can influence carbon cycling of terrestrial ecosystems. However, a general recognition of how soil microorganisms respond to increasing N deposition is not yet reached. We explored soil microbial responses to two levels of N addition (2.5 and 5 gN m(-2) yr(-1)) in interplant soil and beneath shrubs of Haloxylon ammodendron and their consequences to soil respiration in the Gurbantunggut Desert, northwestern China from 2011 to 2013. Microbial biomass and respiration were significantly higher beneath H. ammodendron than in interplant soil. The responses of microbial biomass carbon (MBC) and microbial respiration (MR) showed opposite responses to N addition in interplant and beneath H. ammodendron. N addition slightly increased MBC and MR in interplant soil and decreased them beneath H. ammodendron, with a significant inhibition only in 2012. N addition had no impacts on the total microbial physiological activity, but N addition decreased the labile carbon substrate utilization beneath H. ammodendron when N addition level was high. Phospholipid fatty acid (PLFA) analysis showed that N addition did not alter the soil microbial community structure as evidenced by the similar ratios of fungal to bacterial PLFAs and gram-negative to gram-positive bacterial PLFAs. Microbial biomass and respiration showed close correlations with soil water content and dissolved carbon, and they were independent of soil inorganic nitrogen across three years. Our study suggests that N addition effects on soil microorganisms and carbon emission are dependent on the respiratory substrates and water availability in the desert ecosystem. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Microbial diversity, nitrogen loss and grass production after addition of Effective Micro-organisms® (EM) to slurry manure

    NARCIS (Netherlands)

    Vliet, van P.C.J.; Bloem, J.; Goede, de R.G.M.

    2006-01-01

    In this study, we used a DNA fingerprinting technique (PCR-DGGE) to investigate if bacteria present in an activated EM suspension (EM-A) were able to maintain or reach significant relative abundances after addition to slurry manure. We also investigated effects of the addition of EM-A to slurry

  12. Effects of phosphorus addition on nitrogen cycle and fluxes of N2O and CH4 in tropical tree plantation soils in Thailand

    Directory of Open Access Journals (Sweden)

    Taiki Mori

    2017-04-01

    Full Text Available An incubation experiment was conducted to test the effects of phosphorus (P addition on nitrous oxide (N2O emissions and methane (CH4 uptakes, using tropical tree plantation soils in Thailand. Soil samples were taken from five forest stands—Acacia auriculiformis, Acacia mangium, Eucalyptus camaldulensis, Hopea odorata, and Xylia xylocarpa—and incubated at 80% water holding capacity. P addition stimulated N2O emissions only in Xylia xylocarpa soils. Since P addition tended to increase net ammonification rates in Xylia xylocarpa soils, the stimulated N2O emissions were suggested to be due to the stimulated nitrogen (N cycle by P addition and the higher N supply for nitrification and denitrification. In other soils, P addition had no effects on N2O emissions or soil N properties, except that P addition tended to increase the soil microbial biomass N in Acacia auriculiformis soils. No effects of P addition were observed on CH4 uptakes in any soil. It is suggested that P addition on N2O and CH4 fluxes at the study site were not significant, at least under laboratory conditions.

  13. The Effects of Nitrogen Addition on the Uptake and Allocation of Macro- and Micronutrients in Bothriochloa ischaemum on Loess Plateau in China

    Directory of Open Access Journals (Sweden)

    Zemin Ai

    2017-08-01

    Full Text Available The effects of nitrogen (N addition on the macro- and micronutrient concentrations, storage, and allocation of Bothriochloa ischaemum (L. Keng, a native forage plant on the Loess Plateau in China remain unclear. We studied the effects of N addition at 0 (CK, 2.5 (N1, 5.0 (N2, and 10.0 (N3 g N m-2 y-1. N addition significantly decreased the available copper (Cu, zinc (Zn, and total Cu concentration, but significantly increased the available iron concentration in the soil. Cu, manganese (Mn, and sodium (Na concentrations in aboveground tissues and potassium (K, magnesium, and Zn concentrations in belowground tissues significantly increased with N addition. Calcium (Ca concentrations in belowground tissues decreased significantly. The ratios of above- to belowground Ca, Cu, Zn, and Mn significantly increased with N addition. The maximum ratios appeared at N2 for Cu, Zn, and Mn. The aboveground, belowground, and total biomass storage of studied nutrients significantly changed with N addition, and most attained maximum values under N2 treatment. The storage ratios of above- to belowground Cu, Zn, Mn, and Na attained maximum values at N2. We conclude that N addition significantly, but differentially influence the macro- and micronutrient concentrations and storage in B. ischaemum. B. ischaemum allocated and accumulated increased macro- and micronutrients to its aboveground tissues and exhibited high total storage when the amount of N addition reached 5 g N m-2 y-1.

  14. Water- and plant-mediated responses of ecosystem carbon fluxes to warming and nitrogen addition on the Songnen grassland in northeast China.

    Directory of Open Access Journals (Sweden)

    Li Jiang

    Full Text Available Understanding how grasslands are affected by a long-term increase in temperature is crucial to predict the future impact of global climate change on terrestrial ecosystems. Additionally, it is not clear how the effects of global warming on grassland productivity are going to be altered by increased N deposition and N addition.In-situ canopy CO(2 exchange rates were measured in a meadow steppe subjected to 4-year warming and nitrogen addition treatments. Warming treatment reduced net ecosystem CO(2 exchange (NEE and increased ecosystem respiration (ER; but had no significant impacts on gross ecosystem productivity (GEP. N addition increased NEE, ER and GEP. However, there were no significant interactions between N addition and warming. The variation of NEE during the four experimental years was correlated with soil water content, particularly during early spring, suggesting that water availability is a primary driver of carbon fluxes in the studied semi-arid grassland.Ecosystem carbon fluxes in grassland ecosystems are sensitive to warming and N addition. In the studied water-limited grassland, both warming and N addition influence ecosystem carbon fluxes by affecting water availability, which is the primary driver in many arid and semiarid ecosystems. It remains unknown to what extent the long-term N addition would affect the turn-over of soil organic matter and the C sink size of this grassland.

  15. Inoculation of Trichoderma harzianum on Zea mays its effect on the addition of nitrogen fertilizer at 50%

    Directory of Open Access Journals (Sweden)

    Tavera-Zavala Dulce Daniela

    2017-08-01

    Full Text Available The crop Zea mays (maize requires nitrogen fertilizer (NF usually as NH4NO3 (ammonium nitrate, which applied in excess causes loss of productivity in soil. An alternative to reduce and optimize the dose of NF in crop Z. mays is to inoculate it with Trichoderma harzianum. The main objective was to analyze the effect of three doses of T. harzianum in Z. mays at 50% of NF. This experiment was performed in a greenhouse under an experimental design of random blocks, with 5 treatment and 5 replicates, the re-sponse variables used were: phenology: seedling height (SH and root length (RL, and biomass: aerial and radical fresh/dry weight (AFW/ADW/(RFW/RDW at seedlings and flowering stage, the experimental data were analyzed by Tukey 0.05%. The results showed a positive effect of the specific density of all viable structures of T. harzianum in Z. mays since was observed 92% of seed germination, numerical value statistical difference to the 81% in Z. mays without inoculum and NF at 100% or relative control (RC. At seedling Z. mays with T. harzianum 40 g/100 g seeds registered an ADW of 0.32 g and a RDW of 0.25 g, these values were statistical different to the 0.21 g of ADW, and 0.19 g of RDW in Z. mays without inoculum and fed with NF at 100% or RC. The above mentioned suggests that T. harzi-anum transform seed and root exudates in plant growth promoting substances (PGPS, optimizing the use of NH4NO3 and allowing its reduction until 50% without causing a nutritional deficit on normal Z. mays growth.

  16. Seasonal responses of soil respiration to warming and nitrogen addition in a semi-arid alfalfa-pasture of the Loess Plateau, China.

    Science.gov (United States)

    Fang, Chao; Ye, Jian-Sheng; Gong, Yanhong; Pei, Jiuying; Yuan, Ziqiang; Xie, Chan; Zhu, Yusi; Yu, Yueyuan

    2017-07-15

    Responses of soil respiration (R s ) to increasing nitrogen (N) deposition and warming will have far-reaching influences on global carbon (C) cycling. However, the seasonal (growing and non-growing seasons) difference of R s responses to warming and N deposition has rarely been investigated. We conducted a field manipulative experiment in a semi-arid alfalfa-pasture of northwest China to evaluate the response of R s to nitrogen addition and warming from March 2014 to March 2016. Open-top chambers were used to elevate temperature and N was enriched at a rate of 4.42g m -2 yr -1 with NH 4 NO 3 . Results showed that (1) N addition increased R s by 14% over the two-year period; and (2) warming stimulated R s by 15% in the non-growing season, while inhibited it by 5% in the growing season, which can be explained by decreased plant coverage and soil water. The main effect of N addition did not change with time, but that of warming changed with time, with the stronger inhibition observed in the dry year. When N addition and warming were combined, an antagonistic effect was observed in the growing season, whereas a synergism was observed in the non-growing season. Overall, warming and N addition did not affect the Q10 values over the two-year period, but these treatments significantly increased the Q10 values in the growing season compared with the control treatment. In comparison, combined warming and nitrogen addition significantly reduced the Q10 values compared with the single factor treatment. These results suggest that the negative indirect effect of warming-induced water stress overrides the positive direct effect of warming on R s . Our results also imply the necessity of considering the different R s responses in the growing and non-growing seasons to climate change to accurately evaluate the carbon cycle in the arid and semi-arid regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Short-term nitrous oxide profile dynamics and emissions response to water, nitrogen and carbon additions in two tropical soils

    Science.gov (United States)

    A. D. Nobre; M. Keller; P. M. Crill; R. C. Harriss

    2001-01-01

    Tropical soils are potentially the highest and least studied nitrous oxide (N2O) production areas in the world. The effect of water, nitrate and glucose additions on profile concentrations and episodic emissions of N2O for two volcanic soils in Costa Rica was examined. Magnitudes of episodic N2O pulses, as well as overall N2O emissions, varied considerably and...

  18. Influence of residue and nitrogen fertilizer additions on carbon mineralization in soils with different texture and cropping histories

    Science.gov (United States)

    To improve our ability to predict SOC mineralization response to residue and N additions in soils with different inherent and dynamic organic matter properties, a 330-day incubation was conducted using soil sampled from two long-term experiments (clay loam Mollisols in Iowa [IAsoil] and silt loam Ul...

  19. Short-term enhancement effect of nitrogen addition on microbial degradation and plant uptake of polybrominated diphenyl ethers (PBDEs) in contaminated mangrove soil.

    Science.gov (United States)

    Chen, Juan; Zhou, Hai Chao; Wang, Chao; Zhu, Chun Quan; Tam, Nora Fung-Yee

    2015-12-30

    Effects of nitrogen (N) addition on the microbial degradation and uptake of a mixture of BDE-47 and -209 by Aegiceras corniculatum, a typical mangrove plant species were investigated. At the end of 3-month experiment, a significant dissipation of BDE-47 was observed in the planted soil, and this dissipation, particularly in rhizosphere soil, was significantly accelerated by the frequent addition of N in the form of ammonium chloride. The removal percentage of BDE-47 in the rhizosphere soil without N addition was 47.3% and increased to 58.2% with N. However, the unplanted soil only removed less than 25% BDE-47, irrespective to N supply. The N addition in planted treatments significantly increased soil N content, urease and dehydrogenase activities, and the abundances of total bacteria and dehalogenating bacteria, leading to more microbial degradation of BDE-47. The N addition also enhanced the root uptake and translocation of PBDEs to above-ground tissues of A. corniculatum. These results suggested that N addition could enhance the phytoremediation of BDE-47-contaminated soil within a short period of time. Different from BDE-47, BDE-209 in all contaminated soils was difficult to be removed due to its persistence and low bioavailability. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Impacts of delayed addition of N-rich and acidic substrates on nitrogen loss and compost quality during pig manure composting.

    Science.gov (United States)

    Jiang, Jishao; Kang, Kang; Chen, Dan; Liu, Ningning

    2018-02-01

    Delayed addition of Nitrogen (N)-rich and acidic substrates was investigated to evaluate its effects on N loss and compost quality during the composting process. Three different delayed adding methods of N-rich (pig manure) and acidic substrates (phosphate fertilizer and rotten apples) were tested during the pig manure and wheat straw is composting. The results showed that delayed addition of pig manure and acidic materials led two temperature peaks, and the durations of two separate thermophilic phase were closely related to the amount of pig manure. Delayed addition reduced total N loss by up to 14% when using superphosphate as acidic substrates, and by up to 12% when using rotten apples as acidic substrates, which is mainly due to the decreased NH 3 emissions. At the end of composting, delayed the addition of pig manure caused a significant increase in the HS (humus substance) content, and the highest HS content was observed when 70% of the pig manure was applied at day 0 and the remaining 30% was applied on day 27. In the final compost, the GI in all treatments almost reached the maturity requirement by exceeding 80%. The results suggest that delayed addition of animal manure and acidic substrates could prevent the N loss during composting and improve the compost quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Agricultural management and labile carbon additions affect soil microbial community structure and interact with carbon and nitrogen cycling.

    Science.gov (United States)

    Berthrong, Sean T; Buckley, Daniel H; Drinkwater, Laurie E

    2013-07-01

    We investigated how conversion from conventional agriculture to organic management affected the structure and biogeochemical function of soil microbial communities. We hypothesized the following. (1) Changing agricultural management practices will alter soil microbial community structure driven by increasing microbial diversity in organic management. (2) Organically managed soil microbial communities will mineralize more N and will also mineralize more N in response to substrate addition than conventionally managed soil communities. (3) Microbial communities under organic management will be more efficient and respire less added C. Soils from organically and conventionally managed agroecosystems were incubated with and without glucose ((13)C) additions at constant soil moisture. We extracted soil genomic DNA before and after incubation for TRFLP community fingerprinting of soil bacteria and fungi. We measured soil C and N pools before and after incubation, and we tracked total C respired and N mineralized at several points during the incubation. Twenty years of organic management altered soil bacterial and fungal community structure compared to continuous conventional management with the bacterial differences caused primarily by a large increase in diversity. Organically managed soils mineralized twice as much NO3 (-) as conventionally managed ones (44 vs. 23 μg N/g soil, respectively) and increased mineralization when labile C was added. There was no difference in respiration, but organically managed soils had larger pools of C suggesting greater efficiency in terms of respiration per unit soil C. These results indicate that the organic management induced a change in community composition resulting in a more diverse community with enhanced activity towards labile substrates and greater capacity to mineralize N.

  2. Responses of nitrous oxide emissions to nitrogen and phosphorus additions in two tropical plantations with N-fixing vs. non-N-fixing tree species

    Science.gov (United States)

    Zhang, W.; Zhu, X.; Luo, Y.; Rafique, R.; Chen, H.; Huang, J.; Mo, J.

    2014-09-01

    Leguminous tree plantations at phosphorus (P) limited sites may result in excess nitrogen (N) and higher rates of nitrous oxide (N2O) emissions. However, the effects of N and P applications on soil N2O emissions from plantations with N-fixing vs. non-N-fixing tree species have rarely been studied in the field. We conducted an experimental manipulation of N and/or P additions in two plantations with Acacia auriculiformis (AA, N-fixing) and Eucalyptus urophylla (EU, non-N-fixing) in South China. The objective was to determine the effects of N or P addition alone, as well as NP application together on soil N2O emissions from these tropical plantations. We found that the average N2O emission from control was greater in the AA (2.3 ± 0.1 kg N2O-N ha-1 yr-1) than in EU plantation (1.9 ± 0.1 kg N2O-N ha-1 yr-1). For the AA plantation, N addition stimulated N2O emission from the soil while P addition did not. Applications of N with P together significantly decreased N2O emission compared to N addition alone, especially in the high-level treatments (decreased by 18%). In the EU plantation, N2O emissions significantly decreased in P-addition plots compared with the controls; however, N and NP additions did not. The different response of N2O emission to N or P addition was attributed to the higher initial soil N status in the AA than that of EU plantation, due to symbiotic N fixation in the former. Our result suggests that atmospheric N deposition potentially stimulates N2O emissions from leguminous tree plantations in the tropics, whereas P fertilization has the potential to mitigate N-deposition-induced N2O emissions from such plantations.

  3. The consequences of including non-additive effects on the genetic evaluation of harvest body weight in Coho salmon (Oncorhynchus kisutch

    Directory of Open Access Journals (Sweden)

    Neira Roberto

    2010-06-01

    Full Text Available Abstract Background In this study, we used different animal models to estimate genetic and environmental variance components on harvest weight in two populations of Oncorhynchus kisutch, forming two classes i.e. odd- and even-year spawners. Methods The models used were: additive, with and without inbreeding as a covariable (A + F and A respectively; additive plus common environmental due to full-sib families and inbreeding (A + C + F; additive plus parental dominance and inbreeding (A + D + F; and a full model (A + C + D + F. Genetic parameters and breeding values obtained by different models were compared to evaluate the consequences of including non-additive effects on genetic evaluation. Results Including inbreeding as a covariable did not affect the estimation of genetic parameters, but heritability was reduced when dominance or common environmental effects were included. A high heritability for harvest weight was estimated in both populations (even = 0.46 and odd = 0.50 when simple additive models (A + F and A were used. Heritabilities decreased to 0.21 (even and 0.37 (odd when the full model was used (A + C + D + F. In this full model, the magnitude of the dominance variance was 0.19 (even and 0.06 (odd, while the magnitude of the common environmental effect was lower than 0.01 in both populations. The correlation between breeding values estimated with different models was very high in all cases (i.e. higher than 0.98. However, ranking of the 30 best males and the 100 best females per generation changed when a high dominance variance was estimated, as was the case in one of the two populations (even. Conclusions Dominance and common environmental variance may be important components of variance in harvest weight in O. kisutch, thus not including them may produce an overestimation of the predicted response; furthermore, genetic evaluation was seen to be partially affected, since the ranking of selected animals changed with the inclusion of

  4. Nitrogen addition and harvest frequency rather than initial plant species composition determine vertical structure and light interception in grasslands.

    Science.gov (United States)

    Petersen, Ute; Isselstein, Johannes

    2015-07-21

    In biodiversity experiments based on seeded experimental communities, species richness and species composition exert a strong influence on canopy structure and can lead to an improved use of aboveground resources. In this study, we want to explore whether these findings are applicable to agriculturally managed permanent grassland. Vertical layered profiles of biomass, leaf area (LA) and light intensity were measured in a removal-type biodiversity experiment (GrassMan) to compare the canopy structure in grassland vegetation of different plant species composition (called sward types). Additionally, the altered sward types were subjected to four different management regimes by a combination of the factors fertilization (unfertilized, NPK fertilized) and cutting frequency (one late cut or three cuts). In spite of large compositional differences (ratio grasses : non-leguminous forbs : leguminous forbs ranging from 93 : 7 : 0 to 39 : 52 : 9), the vegetation of the same management regime hardly differed in its canopy structure, whereas the different management regimes led to distinct vertical profiles in the vegetation. However, the allocation of biomass in response to cutting and fertilization differed among the sward types. Vegetation dominated by grasses was denser and had more LA when fertilized compared with vegetation rich in dicots which merely grew taller. In functionally more diverse vegetation, light interception was not increased compared with vegetation consisting of more than 90 % of grasses in terms of biomass. Management had a much stronger influence on structure and light interception than plant species composition in this grassland experiment. Published by Oxford University Press on behalf of the Annals of Botany Company.

  5. Response of aboveground biomass and diversity to nitrogen addition - a five-year experiment in semi-arid grassland of Inner Mongolia, China

    Science.gov (United States)

    He, Kejian; Qi, Yu; Huang, Yongmei; Chen, Huiying; Sheng, Zhilu; Xu, Xia; Duan, Lei

    2016-08-01

    Understanding the response of the plant community to increasing nitrogen (N) deposition is helpful for improving pasture management in semi-arid areas. We implemented a 5-year N addition experiment in a Stipa krylovii steppe of Inner Mongolia, northern China. The aboveground biomass (AGB) and species richness were measured annually. Along with the N addition levels, the species richness declined significantly, and the species composition changed noticeably. However, the total AGB did not exhibit a noticeable increase. We found that compensatory effects of the AGB occurred not only between the grasses and the forbs but also among Gramineae species. The plant responses to N addition, from the community to species level, lessened in dry years compared to wet or normal years. The N addition intensified the reduction of community productivity in dry years. Our study indicated that the compensatory effects of the AGB among the species sustained the stability of grassland productivity. However, biodiversity loss resulting from increasing N deposition might lead the semi-arid grassland ecosystem to be unsustainable, especially in dry years.

  6. Improvement of phenolic antioxidants and quality characteristics of virgin olive oil with the addition of enzymes and nitrogen during olive paste processing

    Energy Technology Data Exchange (ETDEWEB)

    Inconomou, D.; Arapoglou, D.; Israilides, C.

    2010-07-01

    The evolution of phenolic compounds and their contribution to the quality characteristics in virgin olive oil during fruit processing was studied with the addition of a combination of various commercial enzymes containing pectinases, polygalacturonases, cellulase and {beta}-glucanase with or without nitrogen flush. Olive fruits (Olea europaea, L.) of the cultivar Megaritiki, at the semi black pigmentation stage of maturity, were used in a 3-phase extraction system in an experiment at industrial scale. The addition of enzymes in the olive paste during processing increased the total phenol and ortho-diphenol contents, as well as some simple phenolic compounds (3,4-DHPEA, p-HPEA) and the secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEAEA) in olive oil and therefore improved its oxidative stability. Furthermore, enzyme treatment ameliorated the quality parameters of the produced olive oil (acidity and peroxide value) and their sensory attributes. The use of additional N{sub 2} flush with the enzyme treatments did not improve the quality parameters of olive oil any further; however it did not affect the concentration of individual and total sterols or most of the fatty acid composition. Consequently, olive paste treatment with enzymes not only improved the quality characteristics of olive oil and enhanced the overall organoleptic quality, but also increased the olive oil yield. (Author) 33 refs.

  7. Long-term nitrogen addition leads to loss of species richness due to litter accumulation and soil acidification in a temperate steppe.

    Directory of Open Access Journals (Sweden)

    Ying Fang

    Full Text Available BACKGROUND: Although community structure and species richness are known to respond to nitrogen fertilization dramatically, little is known about the mechanisms underlying specific species replacement and richness loss. In an experiment in semiarid temperate steppe of China, manipulative N addition with five treatments was conducted to evaluate the effect of N addition on the community structure and species richness. METHODOLOGY/PRINCIPAL FINDINGS: Species richness and biomass of community in each plot were investigated in a randomly selected quadrat. Root element, available and total phosphorus (AP, TP in rhizospheric soil, and soil moisture, pH, AP, TP and inorganic N in the soil were measured. The relationship between species richness and the measured factors was analyzed using bivariate correlations and stepwise multiple linear regressions. The two dominant species, a shrub Artemisia frigida and a grass Stipa krylovii, responded differently to N addition such that the former was gradually replaced by the latter. S. krylovii and A. frigida had highly-branched fibrous and un-branched tap root systems, respectively. S. krylovii had higher height than A. frigida in both control and N added plots. These differences may contribute to the observed species replacement. In addition, the analysis on root element and AP contents in rhizospheric soil suggests that different calcium acquisition strategies, and phosphorus and sodium responses of the two species may account for the replacement. Species richness was significantly reduced along the five N addition levels. Our results revealed a significant relationship between species richness and soil pH, litter amount, soil moisture, AP concentration and inorganic N concentration. CONCLUSIONS/SIGNIFICANCE: Our results indicate that litter accumulation and soil acidification accounted for 52.3% and 43.3% of the variation in species richness, respectively. These findings would advance our knowledge on the

  8. Nutrient limitation in three lowland tropical forests in southern China receiving high nitrogen deposition: insights from fine root responses to nutrient additions.

    Science.gov (United States)

    Zhu, Feifei; Yoh, Muneoki; Gilliam, Frank S; Lu, Xiankai; Mo, Jiangming

    2013-01-01

    Elevated nitrogen (N) deposition to tropical forests may accelerate ecosystem phosphorus (P) limitation. This study examined responses of fine root biomass, nutrient concentrations, and acid phosphatase activity (APA) of bulk soil to five years of N and P additions in one old-growth and two younger lowland tropical forests in southern China. The old-growth forest had higher N capital than the two younger forests from long-term N accumulation. From February 2007 to July 2012, four experimental treatments were established at the following levels: Control, N-addition (150 kg N ha(-1) yr(-1)), P-addition (150 kg P ha(-1) yr(-1)) and N+P-addition (150 kg N ha(-1) yr(-1) plus 150 kg P ha(-1) yr(-1)). We hypothesized that fine root growth in the N-rich old-growth forest would be limited by P availability, and in the two younger forests would primarily respond to N additions due to large plant N demand. Results showed that five years of N addition significantly decreased live fine root biomass only in the old-growth forest (by 31%), but significantly elevated dead fine root biomass in all the three forests (by 64% to 101%), causing decreased live fine root proportion in the old-growth and the pine forests. P addition significantly increased live fine root biomass in all three forests (by 20% to 76%). The combined N and P treatment significantly increased live fine root biomass in the two younger forests but not in the old-growth forest. These results suggest that fine root growth in all three study forests appeared to be P-limited. This was further confirmed by current status of fine root N:P ratios, APA in bulk soil, and their responses to N and P treatments. Moreover, N addition significantly increased APA only in the old-growth forest, consistent with the conclusion that the old-growth forest was more P-limited than the younger forests.

  9. [Effects of grape seed addition in swine manure-wheat straw composting on the compost microbial community and carbon and nitrogen contents].

    Science.gov (United States)

    Huang, Yi-Mei; Liu, Xue-Ling; Jiang, Ji-Shao; Huang, Hua; Liu, Dong

    2012-08-01

    Taking substrates swine manure and wheat straw (fresh mass ratio 10.5:1) as the control (PMW), a composting experiment was conducted in a self-made aerated static composting bin to study the effects of adding 8% grape seed (treatment PMW + G) on the succession of microbial community and the transformation of carbon and nitrogen in the substrates during the composting. Seven samples were collected from each treatment, according to the temperature of the compost during the 30 d composting period. The microbial population and physiological groups were determined, and the NH4(+)-N, NO3(-)-N, organic N, and organic C concentrations in the compost were measured. Grape seed addition induced a slight increase of bacterial count and a significant increase of actinomycetes count, but decreased the fungal count significantly. Grape seed addition also decreased the ratio of bacteria to actinomycetes and the counts of ammonifiers and denitrifiers, but increased the counts of nitrifiers, N-fixing bacteria, and cellulose-decomposing microorganisms. The contents of NH4(+)-N and organic C decreased, while that of NO3(-)-N increased obviously. The NO3(-)-N content in the compost was positively correlated with the actinomycetes count. During composting, the compost temperature in treatment PMW + G increased more rapidly, and remained steady in thermophilic phase, while the water content changed little, which provided a stable and higher population of actinomycetes and nitrifiers in thermophilic phase, being beneficial to the increase of compost nitrate N.

  10. Effects of adding food by-products mainly including noodle waste to total mixed ration silage on fermentation quality, feed intake, digestibility, nitrogen utilization and ruminal fermentation in wethers.

    Science.gov (United States)

    Ishida, Kyohei; Yani, Srita; Kitagawa, Masayuki; Oishi, Kazato; Hirooka, Hiroyuki; Kumagai, Hajime

    2012-11-01

    Four wethers were used in a 4 × 4 Latin square design experiment to evaluate the applicability of two types of total mixed ration (TMR) silage with food by-products. Four food by-products (i.e., potato waste, soy sauce cake, soybean curd residue and noodle waste) were obtained and mixed with commercial concentrate (CC) as TMR silage. The two types of TMR silage, T1 and T2, each contained CC, in addition to all by-products for T1 (TRE1), and soy sauce cake and noodle waste for T2 (TRE2) on a dry matter (DM) basis. The silage was well-fermented with low pH values and high lactic acid concentration. As the experimental treatments, T1, T2 and CC (CTL) were fed with a basal diet. The result showed that the digestibility of DM and organic matter (OM) were higher for T1 than for CC (P < 0.05), while crude protein digestibility was not significantly different among T1, T2 and CC. The retained nitrogen was not affected by inclusion of food by-products. Ruminal pH in TRE1 and TRE2 immediately decreased compared to that in CTL. The study suggested that the two types of TMR silage, including food by-products, might be used as a substitute for commercial concentrate. © 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.

  11. Thick c-BN films deposited by radio frequency magnetron sputtering in argon/nitrogen gas mixture with additional hydrogen gas

    Science.gov (United States)

    Zhao, Yan; Gao, Wei; Xu, Bo; Li, Ying-Ai; Li, Hong-Dong; Gu, Guang-Rui; Yin, Hong

    2016-10-01

    The excellent physical and chemical properties of cubic boron nitride (c-BN) film make it a promising candidate for various industry applications. However, the c-BN film thickness restricts its practical applications in many cases. Thus, it is indispensable to develop an economic, simple and environment-friend way to synthesize high-quality thick, stable c-BN films. High-cubic-content BN films are prepared on silicon (100) substrates by radio frequency (RF) magnetron sputtering from an h-BN target at low substrate temperature. Adhesions of the c-BN films are greatly improved by adding hydrogen to the argon/nitrogen gas mixture, allowing the deposition of a film up to 5-μm thick. The compositions and the microstructure morphologies of the c-BN films grown at different substrate temperatures are systematically investigated with respect to the ratio of H2 gas content to total working gas. In addition, a primary mechanism for the deposition of thick c-BN film is proposed. Project supported by the National Natural Science Foundation of China (Grant Nos. 51572105, 61504046, and 51272224), the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China, the Development and Reform Commission of Jilin Province, China (Grant No. 2015Y050), and the Scientific Research Foundation for the Returned Overseas of Jilin Province, China.

  12. Neurologic Outcome After Resection of Parietal Lobe Including Primary Somatosensory Cortex: Implications of Additional Resection of Posterior Parietal Cortex.

    Science.gov (United States)

    Kim, Young-Hoon; Kim, June Sic; Lee, Sang Kun; Chung, Chun Kee

    2017-10-01

    Postoperative neurologic outcomes after primary somatosensory cortex (S1) resection have not been well documented. This study was designed to evaluate the neurologic deterioration that follows resection of the S1 areas and to assess the risk factors associated with these morbidities. We reviewed 48 consecutive patients with medically intractable epilepsy who underwent resection of the S1 and/or the adjacent cortex. The 48 patients were categorized into 4 groups according to the resected area as seen on postoperative magnetic resonance images: group 1 (resection of S1 only; n = 4), 2 (the posterior parietal cortex [PPC] only; n = 24), 3 (S1 and PPC; n = 10), and 4 (S1 and precentral gyrus; n = 10). After the resection of S1 areas, 19 patients (40%) experienced neurologic worsening, including 6 (13%) with permanent and 13 (27%) with transient deficits. Patients with permanent deficits included 2 with motor dysphasia, 1 with dysesthesia, 2 with equilibrium impairments, and 1 with fine movement disturbance of the hand. The overall and permanent neurologic risks were 25% and 0% in group 1, 17% and 4% in group 2, 80% and 20% in group 3, and 60% and 30% in group 4, respectively. Multivariate analysis determined that the resection of both S1 and PPC was the only significant risk factor for neurologic deficits (P = 0.002). The neurologic risk of the resection of S1 and/or its adjacent cortical areas was 40%. The additional resection of the PPC was significantly associated with the development of postoperative neurologic impairments. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Nitrogen leaching and acidification during 19 years of NH4NO3 additions to a coniferous-forested catchment at Gardsjoen, Sweden (NITREX)

    International Nuclear Information System (INIS)

    Moldan, Filip; Wright, Richard F.

    2011-01-01

    The role of nitrogen (N) in acidification of soil and water has become relatively more important as the deposition of sulphur has decreased. Starting in 1991, we have conducted a whole-catchment experiment with N addition at Gardsjoen, Sweden, to investigate the risk of N saturation. We have added 41 kg N ha -1 yr -1 as NH 4 NO 3 to the ambient 9 kg N ha -1 yr -1 in fortnightly doses by means of sprinkling system. The fraction of input N lost to runoff has increased from 0% to 10%. Increased concentrations of NO 3 in runoff partially offset the decreasing concentrations of SO 4 and slowed ecosystem recovery from acid deposition. From 1990-2002, about 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. The soil N pool increased by 5%. N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g -1 . - Research highlights: → The fraction of input N lost to runoff has increased from 0% to 10%. → Increased concentrations of NO 3 in runoff slowed ecosystem recovery from acid deposition. → About 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. → N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g -1 . - N addition has led to increased flux of N and increased C sequestration at a forested catchment in Sweden; the NO 3 released has partially offset recovery from acidification.

  14. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Billings NTMS Quadrangle, Montana, including concentrations of forty-three additional elements

    International Nuclear Information System (INIS)

    Broxton, D.E.

    1979-08-01

    This report contains data collected during a geochemical survey for uranium in the Billings quadrangle of south-central Montana. Totals of 1665 water and 1424 sediment samples were collected from 1998 locations in the quadrangle. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters in Appendix I-A and for sediments in Appendix I-B. Uranium/thorium ratios for sediment samples are also included in Appendix I-B. Appendix II describes standard LASL HSSR field and analytical procedures and explains the codes used in Appendix I. In addition to uranium, waters were analyzed for calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, titanium, and zinc (Appendix I-A). Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc (Appendix I-B). All elemental analyzes were performed at the LASL. Water samples delayed neutron counting, and plasma-source emission spectroscopy. Sediments were analyzed by delayed neutron counting, neutron activation analysis, x-ray fluorescence, and arc-source emission spectrography

  15. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Leadville NTMS Quadrangle, Colorado, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Planner, H.N.

    1980-10-01

    A total of 1797 locations was sampled over a 19 330-km 2 area, providing an average density of one sample location per 11 km 2 . This report contains results for uranium in water samples and uranium and 42 additional elements in sediment samples. A total of 1279 water samples was collected from streams (1125) and springs (154). Uranium concentrations for all water samples range from below the detection limit of 0.02 ppB to 37.56 ppB. Mean concentrations in streams and springs are 1.05 ppB and 1.19 ppB, respectively. A total of 1784 sediment samples was collected from streams (1590), springs (193), and one pond. Uranium concentrations in sediments range from 1.27 to 223.80 ppM. Statistical mean uranium concentrations for wet stream (8.55 ppM) and spring (7.51 ppM) sediments are found to be greater than their dry counterparts (5.13 ppM and 4.96 ppM, respectively). Field data, recorded at the collection site, are reported with the elemental concentrations for each water and sediment sample listed. These data include a scintillometer determination of the equivalent uranium, pH and conductivity measurements, and geographic and weather information

  16. Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids

    Science.gov (United States)

    Gering, Kevin L.; Harrup, Mason K.; Rollins, Harry W.

    2015-12-08

    An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.

  17. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Sante Fe NTMS Quadrangle, New Mexico, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Bolivar, S.L.

    1980-05-01

    Totals of 982 water and 1155 sediment samples were collected from 1962 locations. Samples were collected at the nominal reconnaissnce density of one sample location per 10 km 2 . Water samples were collected from streams, springs, and wells and were analyzed for uranium. Sediment samples, taken from streams and springs, were analyzed for uranium, thorium, and 41 additional elements. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. U/Th ratios for sediment samples are included. Uranium analyses for water samples and multielement analyses for sediment samples are reported. A supplemental report containing the results of multielement analyses of water samples will be open filed in the near future. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by DNC. Sediments were analyzed for U and Th, as well as Al, Sb, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sa, Sc, Ag, Na, Sr, Ta, Tb, Sn, Ti, W, V, Yb, and Zn. All sediments were analyzed for U by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectroscopy for 2 elements. Analytical results are reported as ppM. Descriptions of procedures used for analysis of water and sediments samples as well as analytical precisions and detection limits are given

  18. Plant Functional Diversity Can Be Independent of Species Diversity: Observations Based on the Impact of 4-Yrs of Nitrogen and Phosphorus Additions in an Alpine Meadow.

    Science.gov (United States)

    Li, Wei; Cheng, Ji-Min; Yu, Kai-Liang; Epstein, Howard E; Guo, Liang; Jing, Guang-Hua; Zhao, Jie; Du, Guo-Zhen

    2015-01-01

    Past studies have widely documented the decrease in species diversity in response to addition of nutrients, however functional diversity is often independent from species diversity. In this study, we conducted a field experiment to examine the effect of nitrogen and phosphorus fertilization ((NH4)2 HPO4) at 0, 15, 30 and 60 g m-2 yr-1 (F0, F15, F30 and F60) after 4 years of continuous fertilization on functional diversity and species diversity, and its relationship with productivity in an alpine meadow community on the Tibetan Plateau. To this purpose, three community-weighted mean trait values (specific leaf area, SLA; mature plant height, MPH; and seed size, SS) for 30 common species in each fertilization level were determined; three components of functional diversity (functional richness, FRic; functional evenness, FEve; and Rao's index of quadratic entropy, FRao) were quantified. Our results showed that: (i) species diversity sharply decreased, but functional diversity remained stable with fertilization; (ii) community-weighted mean traits (SLA and MPH) had a significant increase along the fertilization level; (iii) aboveground biomass was not correlated with functional diversity, but it was significantly correlated with species diversity and MPH. Our results suggest that decreases in species diversity due to fertilization do not result in corresponding changes in functional diversity. Functional identity of species may be more important than functional diversity in influencing aboveground productivity in this alpine meadow community, and our results also support the mass ratio hypothesis; that is, the traits of the dominant species influenced the community biomass production.

  19. Photosynthetic and growth response of sugar maple (Acer saccharum Marsh.) mature trees and seedlings to calcium, magnesium, and nitrogen additions in the Catskill Mountains, NY, USA

    Science.gov (United States)

    Momen, Bahram; Behling, Shawna J; Lawrence, Gregory B.; Sullivan, Joseph H

    2015-01-01

    Decline of sugar maple in North American forests has been attributed to changes in soil calcium (Ca) and nitrogen (N) by acidic precipitation. Although N is an essential and usually a limiting factor in forests, atmospheric N deposition may cause N-saturation leading to loss of soil Ca. Such changes can affect carbon gain and growth of sugar maple trees and seedlings. We applied a 22 factorial arrangement of N and dolomitic limestone containing Ca and Magnesium (Mg) to 12 forest plots in the Catskill Mountain region of NY, USA. To quantify the short-term effects, we measured photosynthetic-light responses of sugar maple mature trees and seedlings two or three times during two summers. We estimated maximum net photosynthesis (An-max) and its related light intensity (PAR at An-max), apparent quantum efficiency (Aqe), and light compensation point (LCP). To quantify the long-term effects, we measured basal area of living mature trees before and 4 and 8 years after treatment applications. Soil and foliar chemistry variables were also measured. Dolomitic limestone increased Ca, Mg, and pH in the soil Oe horizon. Mg was increased in the B horizon when comparing the plots receiving N with those receiving CaMg. In mature trees, foliar Ca and Mg concentrations were higher in the CaMg and N+CaMg plots than in the reference or N plots; foliar Ca concentration was higher in the N+CaMg plots compared with the CaMg plots, foliar Mg was higher in the CaMg plots than the N+CaMg plots; An-max was maximized due to N+CaMg treatment; Aqe decreased by N addition; and PAR at An-max increased by N or CaMg treatments alone, but the increase was maximized by their combination. No treatment effect was detected on basal areas of living mature trees four or eight years after treatment applications. In seedlings, An-max was increased by N+CaMg addition. The reference plots had an open herbaceous layer, but the plots receiving N had a dense monoculture of common woodfern in the

  20. Photosynthetic and Growth Response of Sugar Maple (Acer saccharum Marsh. Mature Trees and Seedlings to Calcium, Magnesium, and Nitrogen Additions in the Catskill Mountains, NY, USA.

    Directory of Open Access Journals (Sweden)

    Bahram Momen

    Full Text Available Decline of sugar maple in North American forests has been attributed to changes in soil calcium (Ca and nitrogen (N by acidic precipitation. Although N is an essential and usually a limiting factor in forests, atmospheric N deposition may cause N-saturation leading to loss of soil Ca. Such changes can affect carbon gain and growth of sugar maple trees and seedlings. We applied a 22 factorial arrangement of N and dolomitic limestone containing Ca and Magnesium (Mg to 12 forest plots in the Catskill Mountain region of NY, USA. To quantify the short-term effects, we measured photosynthetic-light responses of sugar maple mature trees and seedlings two or three times during two summers. We estimated maximum net photosynthesis (An-max and its related light intensity (PAR at An-max, apparent quantum efficiency (Aqe, and light compensation point (LCP. To quantify the long-term effects, we measured basal area of living mature trees before and 4 and 8 years after treatment applications. Soil and foliar chemistry variables were also measured. Dolomitic limestone increased Ca, Mg, and pH in the soil Oe horizon. Mg was increased in the B horizon when comparing the plots receiving N with those receiving CaMg. In mature trees, foliar Ca and Mg concentrations were higher in the CaMg and N+CaMg plots than in the reference or N plots; foliar Ca concentration was higher in the N+CaMg plots compared with the CaMg plots, foliar Mg was higher in the CaMg plots than the N+CaMg plots; An-max was maximized due to N+CaMg treatment; Aqe decreased by N addition; and PAR at An-max increased by N or CaMg treatments alone, but the increase was maximized by their combination. No treatment effect was detected on basal areas of living mature trees four or eight years after treatment applications. In seedlings, An-max was increased by N+CaMg addition. The reference plots had an open herbaceous layer, but the plots receiving N had a dense monoculture of common woodfern in the

  1. Measurement of [Formula: see text] production with additional jet activity, including [Formula: see text] quark jets, in the dilepton decay channel using pp collisions at [Formula: see text].

    Science.gov (United States)

    Khachatryan, V; Sirunyan, A M; Tumasyan, A; Adam, W; Asilar, E; Bergauer, T; Brandstetter, J; Brondolin, E; Dragicevic, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hartl, C; Hörmann, N; Hrubec, J; Jeitler, M; Knünz, V; König, A; Krammer, M; Krätschmer, I; Liko, D; Matsushita, T; Mikulec, I; Rabady, D; Rahbaran, B; Rohringer, H; Schieck, J; Schöfbeck, R; Strauss, J; Treberer-Treberspurg, W; Waltenberger, W; Wulz, C-E; Mossolov, V; Shumeiko, N; Suarez Gonzalez, J; Alderweireldt, S; Cornelis, T; De Wolf, E A; Janssen, X; Knutsson, A; Lauwers, J; Luyckx, S; Van De Klundert, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Van Spilbeeck, A; Abu Zeid, S; Blekman, F; D'Hondt, J; Daci, N; De Bruyn, I; Deroover, K; Heracleous, N; Keaveney, J; Lowette, S; Moreels, L; Olbrechts, A; Python, Q; Strom, D; Tavernier, S; Van Doninck, W; Van Mulders, P; Van Onsem, G P; Van Parijs, I; Barria, P; Brun, H; Caillol, C; Clerbaux, B; De Lentdecker, G; Fasanella, G; Favart, L; Grebenyuk, A; Karapostoli, G; Lenzi, T; Léonard, A; Maerschalk, T; Marinov, A; Perniè, L; Randle-Conde, A; Reis, T; Seva, T; Vander Velde, C; Yonamine, R; Vanlaer, P; Yonamine, R; Zenoni, F; Zhang, F; Adler, V; Beernaert, K; Benucci, L; Cimmino, A; Crucy, S; Dobur, D; Fagot, A; Garcia, G; Gul, M; Mccartin, J; Ocampo Rios, A A; Poyraz, D; Ryckbosch, D; Salva, S; Sigamani, M; Strobbe, N; Tytgat, M; Van Driessche, W; Yazgan, E; Zaganidis, N; Basegmez, S; Beluffi, C; Bondu, O; Brochet, S; Bruno, G; Caudron, A; Ceard, L; Da Silveira, G G; Delaere, C; Favart, D; Forthomme, L; Giammanco, A; Hollar, J; Jafari, A; Jez, P; Komm, M; Lemaitre, V; Mertens, A; Musich, M; Nuttens, C; Perrini, L; Pin, A; Piotrzkowski, K; Popov, A; Quertenmont, L; Selvaggi, M; Vidal Marono, M; Beliy, N; Hammad, G H; Júnior, W L Aldá; Alves, F L; Alves, G A; Brito, L; Correa Martins Junior, M; Hamer, M; Hensel, C; Mora Herrera, C; Moraes, A; Pol, M E; Rebello Teles, P; Belchior Batista Das Chagas, E; Carvalho, W; Chinellato, J; Custódio, A; Da Costa, E M; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Huertas Guativa, L M; Malbouisson, H; Matos Figueiredo, D; Mundim, L; Nogima, H; Prado Da Silva, W L; Santoro, A; Sznajder, A; Tonelli Manganote, E J; Vilela Pereira, A; Ahuja, S; Bernardes, C A; De Souza Santos, A; Dogra, S; Fernandez Perez Tomei, T R; Gregores, E M; Mercadante, P G; Moon, C S; Novaes, S F; Padula, Sandra S; Romero Abad, D; Ruiz Vargas, J C; Aleksandrov, A; Hadjiiska, R; Iaydjiev, P; Rodozov, M; Stoykova, S; Sultanov, G; Vutova, M; Dimitrov, A; Glushkov, I; Litov, L; Pavlov, B; Petkov, P; Ahmad, M; Bian, J G; Chen, G M; Chen, H S; Chen, M; Cheng, T; Du, R; Jiang, C H; Plestina, R; Romeo, F; Shaheen, S M; Spiezia, A; Tao, J; Wang, C; Wang, Z; Zhang, H; Asawatangtrakuldee, C; Ban, Y; Li, Q; Liu, S; Mao, Y; Qian, S J; Wang, D; Xu, Z; Avila, C; Cabrera, A; Chaparro Sierra, L F; Florez, C; Gomez, J P; Gomez Moreno, B; Sanabria, J C; Godinovic, N; Lelas, D; Puljak, I; Ribeiro Cipriano, P M; Antunovic, Z; Kovac, M; Brigljevic, V; Kadija, K; Luetic, J; Micanovic, S; Sudic, L; Attikis, A; Mavromanolakis, G; Mousa, J; Nicolaou, C; Ptochos, F; Razis, P A; Rykaczewski, H; Bodlak, M; Finger, M; Finger, M; El Sawy, M; El-Khateeb, E; Elkafrawy, T; Mohamed, A; Salama, E; Calpas, B; Kadastik, M; Murumaa, M; Raidal, M; Tiko, A; Veelken, C; Eerola, P; Pekkanen, J; Voutilainen, M; Härkönen, J; Karimäki, V; Kinnunen, R; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Peltola, T; Tuominen, E; Tuominiemi, J; Tuovinen, E; Wendland, L; Talvitie, J; Tuuva, T; Besancon, M; Couderc, F; Dejardin, M; Denegri, D; Fabbro, B; Faure, J L; Favaro, C; Ferri, F; Ganjour, S; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Locci, E; Machet, M; Malcles, J; Rander, J; Rosowsky, A; Titov, M; Zghiche, A; Antropov, I; Baffioni, S; Beaudette, F; Busson, P; Cadamuro, L; Chapon, E; Charlot, C; Dahms, T; Davignon, O; Filipovic, N; Florent, A; Granier de Cassagnac, R; Lisniak, S; Mastrolorenzo, L; Miné, P; Naranjo, I N; Nguyen, M; Ochando, C; Ortona, G; Paganini, P; Pigard, P; Regnard, S; Salerno, R; Sauvan, J B; Sirois, Y; Strebler, T; Yilmaz, Y; Zabi, A; Agram, J-L; Andrea, J; Aubin, A; Bloch, D; Brom, J-M; Buttignol, M; Chabert, E C; Chanon, N; Collard, C; Conte, E; Coubez, X; Fontaine, J-C; Gelé, D; Goerlach, U; Goetzmann, C; Le Bihan, A-C; Merlin, J A; Skovpen, K; Van Hove, P; Gadrat, S; Beauceron, S; Bernet, C; Boudoul, G; Bouvier, E; Carrillo Montoya, C A; Chierici, R; Contardo, D; Courbon, B; Depasse, P; El Mamouni, H; Fan, J; Fay, J; Gascon, S; Gouzevitch, M; Ille, B; Lagarde, F; Laktineh, I B; Lethuillier, M; Mirabito, L; Pequegnot, A L; Perries, S; Ruiz Alvarez, J D; Sabes, D; Sgandurra, L; Sordini, V; Vander Donckt, M; Verdier, P; Viret, S; Toriashvili, T; Lomidze, D

    2016-01-01

    Jet multiplicity distributions in top quark pair ([Formula: see text]) events are measured in pp collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC using a data set corresponding to an integrated luminosity of 19.7[Formula: see text]. The measurement is performed in the dilepton decay channels ([Formula: see text], [Formula: see text], and [Formula: see text]). The absolute and normalized differential cross sections for [Formula: see text] production are measured as a function of the jet multiplicity in the event for different jet transverse momentum thresholds and the kinematic properties of the leading additional jets. The differential [Formula: see text] and [Formula: see text] cross sections are presented for the first time as a function of the kinematic properties of the leading additional [Formula: see text] jets. Furthermore, the fraction of events without additional jets above a threshold is measured as a function of the transverse momenta of the leading additional jets and the scalar sum of the transverse momenta of all additional jets. The data are compared and found to be consistent with predictions from several perturbative quantum chromodynamics event generators and a next-to-leading order calculation.

  2. Improvement of phenolic antioxidants and quality characteristics of virgin olive oil with the addition of enzymes and nitrogen during olive paste processing

    Directory of Open Access Journals (Sweden)

    Iconomou, D.

    2010-09-01

    Full Text Available The evolution of phenolic compounds and their contribution to the quality characteristics in virgin olive oil during fruit processing was studied with the addition of a combination of various commercial enzymes containing pectinases, polygalacturonases, cellulase and β-glucanase with or without nitrogen flush. Olive fruits (Olea europaea, L. of the cultivar Megaritiki, at the semi black pigmentation stage of maturity, were used in a 3-phase extraction system in an experiment at industrial scale. The addition of enzymes in the olive paste during processing increased the total phenol and ortho-diphenol contents, as well as some simple phenolic compounds (3,4-DHPEA, p-HPEA and the secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEAEA in olive oil and therefore improved its oxidative stability. Furthermore, enzyme treatment ameliorated the quality parameters of the produced olive oil (acidity and peroxide value and their sensory attributes. The use of additional N2 flush with the enzyme treatments did not improve the quality parameters of olive oil any further; however it did not affect the concentration of individual and total sterols or most of the fatty acid composition. Consequently, olive paste treatment with enzymes not only improved the quality characteristics of olive oil and enhanced the overall ogranoleptic quality, but also increased the olive oil yield.

    La evolución de los compuestos fenólicos y su contribución a las caracterísiticas de calidad de aceite de oliva virgen durante el procesado del fruto fue estudiado mediante la adición de una combinación de varias enzimas comerciales conteniendo pectinasas, poligalacturonasa, celulasa y β-glucanasa con y sin flujo de nitrógeno. Las aceitunas (Olea europaea, L. de la variedad Megaritiki, con un estado de madurez correspondiente a una pigmentación semi-negra, fueron usadas en un experimento a escala industrial mediante un sistema de extracción de 3-fase. La

  3. Nitrogen (N) dynamics in the mineral soil of a Central Appalachian hardwood forest during a quarter century of whole-watershed N additions

    Science.gov (United States)

    Frank S. ​Gilliam; Christopher A. Walter; Mary Beth Adams; William T. Peterjohn

    2018-01-01

    The structure and function of terrestrial ecosystemsare maintained by processes that vary with temporal and spatial scale. This study examined temporal and spatial patterns of net nitrogen (N) mineralization and nitrification in mineral soil of three watersheds at the Fernow Experimental Forest, WV: 2 untreated watersheds and 1 watershed receiving aerial applications...

  4. Opposing Effects of Nitrogen and Water addition on Soil Bacterial and Fungal Communities in the Inner Mongolia steppe: a field experiment

    NARCIS (Netherlands)

    Ma, H.; Bai, Guang-ying; Sun, Yang; Kostenko, O.; Zhu, Xiang; Lin, Shan; Ruan, Wei-Bin.; Zhao, Nian-xi; Bezemer, T. Martijn

    2016-01-01

    Grasslands are important ecosystems and make up 40% of the terrestrial ecosystems worldwide. The Inner Mongolia steppe is the main grassland region of China, and nitrogen (N) and water availability are two important factors that limit the productivity of these grasslands. We tested how N and water

  5. Monitoring the extraction of additives and additive degradation products from polymer packaging into solutions by multi-residue method including solid phase extraction and ultra-high performance liquid chromatography-tandem mass spectrometry analysis.

    Science.gov (United States)

    Pouech, Charlène; Lafay, Florent; Wiest, Laure; Baudot, Robert; Léonard, Didier; Cren-Olivé, Cécile

    2014-02-01

    The use of polymer materials in industry for product packaging is increasing. The presence of additives in the polymer matrix enables the modification or improvement of the properties and performance of the polymer, but these industries are concerned regarding the extractability of these additives. The quantification of these additives is particularly challenging because of the presence of these substances as contaminants in all the analytical equipment and the diversity of their physicochemical properties. In this context, a multi-residue analytical method was developed for the trace analysis of the twenty main additives (and their degradation products) authorized in plastic products such as pharmaceutical packaging (e.g., antioxidants, release agents, and light absorbers). This analytical method consisted of a solid phase extraction (SPE) followed by an analysis using ultra-high performance liquid chromatography coupled to a tandem mass spectrometer (UHPLC-MS/MS). A comparison of two ionization interfaces and the optimization of the extraction procedure were discussed. The influence of the quality of the solvent type (distilled versus not distilled) and the nature of the SPE cartridges (Polypropylene versus Teflon(®)) were demonstrated. The optimized method exhibited a quantification limit lower than 20 ng mL(-1) and recoveries between 70 % and 120 % for all compounds. Finally, the method was validated according to the ICH directive and was subsequently applied to the extraction of polymers under different pH conditions and storage temperatures. To the best of our knowledge, this study presents the first methodology allowing the simultaneous quantification of 24 additives at low ng mL(-1).

  6. Study Modules for Calculus-Based General Physics. [Includes Modules 1 and 2: Dimensions and Vector Addition; Rectilinear Motion; plus a Trigonometry and Calculus Review].

    Science.gov (United States)

    Fuller, Robert G., Ed.; And Others

    This is part of a series of 42 Calculus Based Physics (CBP) modules totaling about 1,000 pages. The modules include study guides, practice tests, and mastery tests for a full-year individualized course in calculus-based physics based on the Personalized System of Instruction (PSI). The units are not intended to be used without outside materials;…

  7. Effects of experimental warming and nitrogen addition on soil respiration and CH4 fluxes from crop rotations of winter wheat–soybean/fallow

    DEFF Research Database (Denmark)

    Liu, L; Hu, C; Yang, P

    2015-01-01

    experiment was conducted at Luancheng research station in the North China Plain from 2008 to 2013. Two levels of temperature (T: increase on average 1.5 °C at 5 cm soil depth by infrared heaters, C: ambient temperature) were combined with two levels of nitrogen (N) treatments (N1: with 315 kg N ha−1 y−1, N0...... by affecting soil NH4 concentration. Across years, CH4 emissions were negatively correlated with soil temperature in N1 treatment. Soil respiration showed clear seasonal fluctuations, with the largest emissions during summer and smallest in winter. Warming and nitrogen fertilization had no significant effects...... drying offsetting the effects of soil temperature; or (2) adaption of soil respiration to increased temperature....

  8. Comparison of point injection and top-dressing application of nitrogen fertilizers with sulphur addition in winter rape (Brassica napus L. in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Lucie Peklová

    2015-03-01

    Full Text Available In this paper, we are analyzing the yield and yield parameters of winter rape, fertilized using CULTAN system (Controlled Uptake Long Term Ammonium Nutrition in comparison with top-dressing application of nitrogen fertilizers, which were studied on Haplic Luvisol over 5 years. No significant differences in seed yields between the two systems of fertilization were observed in 2008, 2009 and 2011. The effect of sulphur on a higher seed yield was proved in 2010 and 2012. The seed yield was higher by 11.4% in the treatments with sulphur amendment regardless of the system of fertilization in 2010. The seed yield was higher by 18.2 % in the CULTAN treatment with sulphur adittion in comparison to CULTAN treatment with no sulphur added in 2012. Nitrogen supply was ample in the first flowers open growth stage of winter rape in 2009, 2010 and 2012. The plant height was significantly lower after CULTAN method and as well as higher values of 1000 seed weight were recorded in comparison to top-dressing application in 2009. Nitrogen uptake by seed dry matter was the highest in the year 2009, which corresponds to the achieved seed yields this year.

  9. Uranium hydrogeochemical and stream sediment reconnaissance of the Dalhart NTMS quadrangle, New Mexico/Texas/Oklahoma, including concentrations of forty-two additional elements

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, T.L.

    1980-08-01

    Totals of 1583 water samples and 503 sediment samples were collected from 2028 locations within the 20 000-km/sup 2/ area of the quadrangle at an average density of one location per 9.86 km/sup 2/. Water samples were collected from wells, springs, and streams and were analyzed for uranium. Sediment samples were collected from streams and springs and were analyzed for uranium, thorium, and 41 additional elements. All field and analytical data are listed in the appendixes of this report. Discussion is limited to anomalous samples, which are considered to be those containing over 20 ppB uranium for waters and over 5 ppM uranium for sediments. Uranium concentrations in water samples range from below the detection limit of 0.2 ppB to 1457.65 ppB and average 7.41 ppB. Most of the seventy anomalous water samples (4.4% of all water samples) are grouped spatially into five clusters or areas of interest. Samples in three of the clusters were collected along the north edge of the quadrangle where Mesozoic strata are exposed. The other two clusters are from the central and southern portions where the Quaternary Ogallala formation is exposed. Sediment samples from the quadrangle have uranium concentrations that range from 0.90 ppM to 27.20 ppM and average 3.27 ppM. Fourteen samples (2.8% of all sediment samples) contain over 5 ppM uranium and are considered anomalous. The five samples with the highest concentrations occur where downcutting streams expose Cretaceous units beneath the Quaternary surficial deposits. The remaining anomalous sediment samples were collected from scattered locations and do not indicate any single formation or unit as a potential source for the anomalous concentrations.

  10. Uranium hydrogeochemical and stream sediment reconnaissance of the Dalhart NTMS quadrangle, New Mexico/Texas/Oklahoma, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Morgan, T.L.

    1980-08-01

    Totals of 1583 water samples and 503 sediment samples were collected from 2028 locations within the 20 000-km 2 area of the quadrangle at an average density of one location per 9.86 km 2 . Water samples were collected from wells, springs, and streams and were analyzed for uranium. Sediment samples were collected from streams and springs and were analyzed for uranium, thorium, and 41 additional elements. All field and analytical data are listed in the appendixes of this report. Discussion is limited to anomalous samples, which are considered to be those containing over 20 ppB uranium for waters and over 5 ppM uranium for sediments. Uranium concentrations in water samples range from below the detection limit of 0.2 ppB to 1457.65 ppB and average 7.41 ppB. Most of the seventy anomalous water samples (4.4% of all water samples) are grouped spatially into five clusters or areas of interest. Samples in three of the clusters were collected along the north edge of the quadrangle where Mesozoic strata are exposed. The other two clusters are from the central and southern portions where the Quaternary Ogallala formation is exposed. Sediment samples from the quadrangle have uranium concentrations that range from 0.90 ppM to 27.20 ppM and average 3.27 ppM. Fourteen samples (2.8% of all sediment samples) contain over 5 ppM uranium and are considered anomalous. The five samples with the highest concentrations occur where downcutting streams expose Cretaceous units beneath the Quaternary surficial deposits. The remaining anomalous sediment samples were collected from scattered locations and do not indicate any single formation or unit as a potential source for the anomalous concentrations

  11. Petrographic and Geochemical Characterization of Ore-Bearing Intrusions of the Noril'sk type, Siberia; With Discussion of Their Origin, Including Additional Datasets and Core Logs

    Science.gov (United States)

    Czamanske, Gerald K.

    2002-01-01

    The Noril'sk I, Talnakh, and Kharaelakh intrusions of the Noril'sk district host one of the outstanding metal concentrations in the world; contained Cu-Ni resources are comparable to the deposits at Sudbury, Ontario and the platinum group element (PGE) resource is second only to that of the Bushveld Complex. Our opportunity to cooperatively sample and study this district in Siberian Russia arose in 1990 through a memorandum of understanding between the U.S. Geological Survey and the former Ministry of Geology of the U.S.S.R. The world-class significance of these deposits and the possibility that understanding their geologic context, including construction of a credible 'ore-deposit model,' will lead to discovery of similar deposits elsewhere, inspired extensive studies of the ores, the mafic-intrusions which host them, and associated flood basalts.

  12. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Elk City NTMS Quadrangle, Idaho/Montana, including concentrations of forty-five additional elements

    Energy Technology Data Exchange (ETDEWEB)

    Broxton, D.E.; Beyth, M.

    1980-07-01

    Totals of 1580 water and 1720 sediment samples were collected from 1754 locations in the quadrangle. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters in Appendix I-A and for sediments in Appendix I-B. Uranium/thorium ratios for sediment samples are also included in Appendix I-B. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 parts per billion (ppB) uranium were reanalyzed by delayed-neutron counting (DNC). A supplemental report containing the multielement analyses of water samples will be open filed in the near future. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, selenium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, zinc, and zirconium. Basic statistics for 40 of these elements are presented. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million.

  13. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Lewistown NTMS Quadrangle, Montana, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Shannon, S.S. Jr.

    1980-08-01

    Totals of 758 water and 1170 sediment samples were collected from 1649 locations in the Levistown quadrangle. Water samples were collected at streams, springs, wells, ponds, and marshes; sediment samples were obtained from streams, springs, and ponds. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. All samples were collected at the nominal reconnaissance density of one sample location per 10 km 2 . Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. Uranium to thorium (U/Th) ratios for sediment samples are included. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB U were reanalyzed by delayed-neutron counting. Sediments were analyzed for U and Th as well as Al, Sb, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sa, Sc, Ag, Na, Sr, Ta, Tb, Sn, Ti, W, V, Yb, and Zn. All sediments were analyzed for U by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results are reported as parts per million. Descriptions of procedures used for analysis of water and sediments samples as well as analytical precisions and detection limits are given

  14. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Torrington NTMS quadrangle, Wyoming, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Shannon, S.S. Jr.; Romero, M.T.; Simi, O.R.; Martell, C.J.; Minor, M.M.; Hensley, W.K.; Mills, C.S.

    1980-07-01

    This report contains data collected during a geochemical survey (August and September 1977) for uranium in the Torrington National Topographic Map Series quadrangle of east-central Wyoming by the Los Alamos Scientific Laboratory (LASL) as part of the nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 1119 water and 756 sediment samples were collected from 1677 locations in the quadrangle. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. Uranium/thorium ratios for sediment samples are included. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron-activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million

  15. Detailed uranium hydrogeochemical and stream sediment reconnaissance data release for the eastern portion of the Montrose NTMS Quadrangle, Colorado, including concentrations of forty-five additional elements

    International Nuclear Information System (INIS)

    Maassen, L.W.

    1981-01-01

    In September and October 1979, the Los Alamos Scientific Laboratory (LASL) conducted a detailed geochemical survey for uranium primarily in the Sawatch Range in the eastern part of the Montrose National Topographic Map Series (NTMS) quadrangle, Colorado, as part of the National Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 1034 water and 2087 sediment samples were collected from streams and springs from 2088 locations within a 5420-km 2 area. Statistical data for uranium concentrations in water and sediment samples are presented. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments in appendices. Uranium/thorium ratios for sediment samples are also included. This report contains uranium analyses for water samples and multielement analyses for sediment samples. Sediments were analyzed for uranium and thorium as well as Al, Sb, As, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sm, Sc, Se, Ag, Na, Sr, Ta, Tb, Sn, Ti, W, V, Yb, Zn, and Zr. All elemental analyses were performed at the LASL. Water samples were analyzed for uranium by fluorometry. Sediments were analyzed for uranium by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Descriptions of procedures as analytical precisions and detection limits are given in the appendix

  16. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Rock Springs NTMS Quadrangle, Wyoming, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Morgan, T.L.

    1981-01-01

    This report contains data collected by the Los Alamos Scientific Laboratory (LASL) during a regional geochemical survey for uranium in the Rock Springs National Topographic Map Series (NTMS) quadrangle, southwestern Wyoming, as part of the nationwide hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 397 water and 1794 sediment samples were collected from 1830 locations in the Rock Springs quadrangle of southern Wyoming during the summer of 1976. The average uranium concentration of all water samples is 6.57 ppb and the average sediment uranium concentration is 3.64 ppM. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments in the appendices. Uranium/thorium ratios for sediment samples are also included. A sample location overlay (Plate I) at 1:250 000 scale for use in conjunction with the Rock Springs NTMS quadrangle sheet (US Geological Survey, 1954) is provided. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting. Sediments were analyzed for uranium and thorium as well as Al, Sb, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sm, Sc, Ag, Na, Sr, Ta, Tb, Sn, T, W, V, Yb, and Zn. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. These analytical methods are described briefly in the appendix. This report is simply a data release and is intended to make the data available to the DOE and to the public as quickly as possible

  17. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Butte NTMS Quadrangle, Montana, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Broxton, D.E.; George, W.E.; Montoya, J.V.; Martell, C.J.; Hensley, W.K.; Hanks, D.

    1980-05-01

    This report contains data collected during a geochemical survey for uranium in the Butte National Topographic Map Series (NTMS) quadrangle of west-central Montana. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. Uranium/thorium ratios for sediment samples are also included. This report contains uranium analyses for water samples and multielement analyses for sediment samples. A supplemental report containing the results of multielement analyses of water samples will be open filed in the near future. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million. Descriptions of procedures used for analysis of water and sediment samples as well as analytical precisions and detection limits are given

  18. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Ashton NTMS quadrangle, Idaho/Montana/Wyoming, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Shannon, S.S. Jr; Sandoval, W.F.; Gallimore, D.L.; Hansel, J.M.; Hensley, W.K.; Pirtle, J.; Macdonell, C.J.

    1980-08-01

    This report contains data collected during a geochemical survey for uranium in the Ashton National Topographic Map Series quadrangle of eastern Idaho, southwestern Montana, and northwestern Wyoming by the Los Alamos Scientific Laboratory (LASL) as part of the nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). The LASL is responsible for conducting the HSSR primarily in the Rocky Mountain states of New Mexico, Colorado, Wyoming, and Montana and in Alaska. Totals of 1141 water and 1500 sediment samples were collected from 1539 locations in the quadrangle by a commercial contractor. Water samples were collected at streams, springs, wells, ponds, and marshes; sediment samples were obtained from streams, springs, and ponds. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Uranium/thorium ratios for sediment samples are also included. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million

  19. Uranium hydrogeochemical and stream sediment reconnaissance data release for Saint Johns NTMS quadrangle, Arizona/New Mexico including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Maassen, L.W.; George, W.E.; Apel, C.T.; Hansel, J.M.; Hensley, W.K.; Minor, M.M.; Mills, C.F.

    1980-08-01

    This report contains data collected during a geochemical survey for uranium in the St. Johns National Topographic Map Series (NTMS) quadrangle of Arizona/New Mexico by the Los Alamos Scientific Laboratory (LASL) as part of the nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 848 water and 1475 sediment samples were collected from 2136 locations in the quadrangle. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Listings of the field and uranium data for water samples are given in Appendix I-A. Listings of the field and elemental data for sediment samples are given in Appendix I-B. Uranium/thorium ratios for sediment samples are also included. Appendix II describes standard LASL HSSR field and analytical procedures and explains the codes used in Appendix I. Water samples were initially analyzed for uranium by fluorometry. Water samples collected in 1976 containing more than 10 ppB uranium and those collected in 1979 containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron-activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectroscopy for 2 elements. Analytical results for sediments are reported as parts per million

  20. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Rock Springs NTMS quadrangle, Wyoming, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Morgan, T.L.; George, W.E.; Gallimore, D.L.; Hansel, J.M.; Hensley, W.K.; Jackson, C.K.; Bunker, M.E.

    1981-01-01

    Totals of 397 water and 1794 sediment samples were collected from 1830 locations in the Rock Springs quadrangle of southern Wyoming during the summer of 1976. Water samples were collected from 230 streams, 123 springs, 28 wells, and 16 artificial ponds. Sediment samples were collected from 231 wet streams and 1389 dry streams, 119 wet springs and 8 dry springs 29 artificial ponds and 18 natural ponds. The average uranium concentration of all water samples if 6.57 ppB and the average sediment uranium concentration is 3.64 ppM. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments in Appendices. Uranium/thorium ratios for sediment samples are also included. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. These analytical methods are described briefly

  1. Uranium hydrogeochemical and stream sediment reconnaissance of the vernal NTMS quadrangle, Utah/Colorado, including concentrations of forty-two additional elements

    International Nuclear Information System (INIS)

    Purson, J.D.

    1980-08-01

    The Los Alamos Scientific Laboratory conducted a geochemical reconnaissance for uranium in the Vernal NTMS quadrangle, Utah/Colorado, in the summers of 1977 and 1978. Totals of 422 water and 1552 sediment samples were collected from 1652 locations. These samples were collected at an average density of one sample location per 11 km 2 over an 18,800 km 2 area. Water samples were collected from streams and springs. Only those samples containing >10 ppB uranium for waters and >8 ppM uranium for sediments are discussed; however, all field and analytical data are included in the appendixes. The uranium concentrations in waters range from below the detection limit of 0.01 ppB to 108.04 ppB, with a mean uranium concentration for all water types of 3.11 ppB. Three clusters of samples containing relatively high uranium values are defined; they are associated with the Duchesne River formation, the Mancos shale, or the Uinta Mountain group and Browns Park formations. A few of the samples having the highest uranium values are associated with host rocks favorable for significant uranium mineralization. Sediments collected in this study have uranium concentrations that range between 0.70 ppM and 56.70 ppM, with a mean of 3.46 ppM. The majority of sediment samples with relatively high uranium concentrations were collected from one area in the Sand Wash basin in the northeastern corner of the quadrangle and are associated with the Wasatch formation. None of the water clusters define areas of significant interest; however, the area having high uranium values in sediments is worthy of further study

  2. A 6-year-long manipulation with soil warming and canopy nitrogen additions does not affect xylem phenology and cell production of mature black spruce

    Directory of Open Access Journals (Sweden)

    Madjelia Cangre Ebou eDAO

    2015-11-01

    Full Text Available The predicted climate warming and increased atmospheric inorganic nitrogen deposition are expected to have dramatic impacts on plant growth. However, the extent of these effects and their interactions remains unclear for boreal forest trees. The aim of this experiment was to investigate the effects of increased soil temperature and nitrogen (N depositions on stem intra-annual growth of two mature stands of black spruce [Picea mariana (Mill. BSP] in Quebec, Canada. During 2008-2013, the soil around mature trees was warmed up by 4 °C with heating cables during the growing season and precipitations containing three times the current inorganic N concentration were added by frequent canopy applications. Xylem phenology and cell production were monitored weekly from April to October. The 6-year-long experiment performed in two sites at different altitude showed no substantial effect of warming and N-depositions on xylem phenological phases of cell enlargement, wall thickening and lignification. Cell production, in terms of number of tracheids along the radius, also did not differ significantly and followed the same patterns in control and treated trees. These findings allowed the hypothesis of a medium-term effect of soil warming and N depositions on the growth of mature black spruce to be rejected.

  3. Nitrogen-Doped Co3O4Mesoporous Nanowire Arrays as an Additive-Free Air-Cathode for Flexible Solid-State Zinc-Air Batteries.

    Science.gov (United States)

    Yu, Minghao; Wang, Zhengke; Hou, Cheng; Wang, Zilong; Liang, Chaolun; Zhao, Cunyuan; Tong, Yexiang; Lu, Xihong; Yang, Shihe

    2017-04-01

    The kinetically sluggish rate of oxygen reduction reaction (ORR) on the cathode side is one of the main bottlenecks of zinc-air batteries (ZABs), and thus the search for an efficient and cost-effective catalyst for ORR is highly pursued. Co 3 O 4 has received ever-growing interest as a promising ORR catalyst due to the unique advantages of low-cost, earth abundance and decent catalytic activity. However, owing to the poor conductivity as a result of its semiconducting nature, the ORR activity of the Co 3 O 4 catalyst is still far below the expectation. Herein, we report a controllable N-doping strategy to significantly improve the catalytic activity of Co 3 O 4 for ORR and demonstrate these N doped Co 3 O 4 nanowires as an additive-free air-cathode for flexible solid-state zinc-air batteries. The results of experiments and DFT calculations reveal that the catalytic activity is promoted by the N dopant through a combined set of factors, including enhanced electronic conductivity, increased O 2 adsorption strength and improved reaction kinetics. Finally, the assembly of all-solid-state ZABs based on the optimized cathode exhibit a high volumetric capacity of 98.1 mAh cm -3 and outstanding flexibility. The demonstration of such flexible ZABs provides valuable insights that point the way to the redesign of emerging portable electronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Total Nitrogen Deposition (wet+dry) from the Atmosphere

    Data.gov (United States)

    U.S. Environmental Protection Agency — Oxides of Nitrogen are emitted primarily as by-products of combustion. Sources include power plants, industrial boilers, and automobiles. In addition, agricultural...

  5. Effects of phosphorus addition on nitrogen cycle and fluxes of N2O and CH4 in tropical tree plantation soils in Thailand

    OpenAIRE

    Taiki Mori; Chongrak Wachrinrat; Duriya Staporn; Ponthep Meunpong; Warawich Suebsai; Kazuki Matsubara; Khitja Boonsri; Warisa Lumban; Manassawee Kuawong; Thanida Phukdee; Juruwan Srifai; Kannika Boonman

    2017-01-01

    An incubation experiment was conducted to test the effects of phosphorus (P) addition on nitrous oxide (N2O) emissions and methane (CH4) uptakes, using tropical tree plantation soils in Thailand. Soil samples were taken from five forest stands—Acacia auriculiformis, Acacia mangium, Eucalyptus camaldulensis, Hopea odorata, and Xylia xylocarpa—and incubated at 80% water holding capacity. P addition stimulated N2O emissions only in Xylia xylocarpa soils. Since P addition tended to increase net a...

  6. Impact of the addition of different plant residues on nitrogen mineralization-immobilization turnover and carbon content of a soil incubated under laboratory conditions

    Science.gov (United States)

    Kaleeem Abbasi, M.; Tahir, M. Mahmood; Sabir, N.; Khurshid, M.

    2015-02-01

    Application of plant residues as soil amendment may represent a valuable recycling strategy that affects carbon (C) and nitrogen (N) cycling in soil-plant systems. The amount and rate of nutrient release from plant residues depend on their quality characteristics and biochemical composition. A laboratory incubation experiment was conducted for 120 days under controlled conditions (25 °C and 58% water-filled pore space) to quantify initial biochemical composition and N mineralization of leguminous and non-leguminous plant residues, i.e., the roots, shoots and leaves of Glycine max, Trifolium repens, Zea mays, Populus euramericana, Robinia pseudoacacia and Elaeagnus umbellata, incorporated into the soil at the rate of 200 mg residue N kg-1 soil. The diverse plant residues showed a wide variation in total N, C, lignin, polyphenols and C / N ratio with higher polyphenol content in the leaves and higher lignin content in the roots. The shoot of Glycine max and the shoot and root of Trifolium repens displayed continuous mineralization by releasing a maximum of 109.8, 74.8 and 72.5 mg N kg-1 and representing a 55, 37 and 36% recovery of N that had been released from these added resources. The roots of Glycine max and Zea mays and the shoot of Zea mays showed continuous negative values throughout the incubation. After an initial immobilization, leaves of Populus euramericana, Robinia pseudoacacia and Elaeagnus umbellata exhibited net mineralization by releasing a maximum of 31.8, 63.1 and 65.1 mg N kg-1, respectively, and representing a 16, 32 and 33% N recovery, respectively. Nitrogen mineralization from all the treatments was positively correlated with the initial residue N contents (r = 0.89; p ≤ 0.01) and negatively correlated with lignin content (r = -0.84; p ≤ 0.01), C / N ratio (r = -0.69; p ≤ 0.05), lignin / N ratio (r = -0.68; p ≤ 0.05), polyphenol / N ratio (r = -0.73; p ≤ 0.05) and (lignin + polyphenol) : N ratio (r = -0.70; p ≤ 0.05) indicating a

  7. Experimental and numerical studies of the effects of hydrogen addition on the structure of a laminar methane-nitrogen jet in hot coflow under MILD conditions

    NARCIS (Netherlands)

    Sepman, Alexey; Abtahizadeh, Ebrahim; Mokhov, Anatoli; van Oijen, Jeroen; Levinsky, Howard; de Goey, Philip

    2013-01-01

    In this work we investigate the effects of hydrogen addition on the flame structure of MILD combustion both experimentally and numerically using a laminar-jet-in-hot-coflow (LJHC) geometry. The addition of hydrogen appreciably decreases the flame height (similar to 25%), however only modestly

  8. Influence of ensiling, exogenous protease addition, and bacterial inoculation on fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility in rehydrated and high-moisture corn.

    Science.gov (United States)

    Ferraretto, L F; Fredin, S M; Shaver, R D

    2015-10-01

    Exogenous protease addition may be an option to increase proteolysis of zein proteins and thus starch digestibility in rehydrated and high-moisture corn (HMC) ensiled for short periods. In addition, microbial inoculation may accelerate fermentation and increase acid production and thus increase solubilization of zein proteins. Four experiments were performed to evaluate the effect on fermentation profile, N fractions, and ruminal in vitro starch digestibility (ivSD) of the following: (1) rehydration and ensiling of dry ground corn; (2) exogenous protease addition to rehydrated un-ensiled and ensiled corn; (3) exogenous protease addition or inoculation in rehydrated ensiled corn; and (4) exogenous protease addition or inoculation in HMC. Experiments 1, 2, and 3 were performed with 7 treatments: dry ground corn (DGC); DGC rehydrated to a targeted dry matter content of 70% (REH); REH treated with exogenous protease (REH+); REH ensiled for 30 d (ENS); ENS treated with exogenous protease (ENS+); ENS treated with a microbial inoculant containing Lactobacillus plantarum, Lactobacillus casei, Enterococcus faecium, and Pediococcus sp. (ENSI); and ENS treated with exogenous protease and microbial inoculant (ENSI+). Experiment 1 compared DGC, REH, and ENS with ivSD being greater for ENS (64.9%) than DGC and REH (51.7% on average). Experiment 2 compared REH and ENS without or with exogenous protease addition (REH+ and ENS+, respectively). Ensiling and exogenous protease addition increased ivSD, but exogenous protease addition was more effective in ENS than REH (6.4 vs. 2.6 percentage unit increase). Experiment 3 compared the effects of exogenous protease addition and inoculation in ENS corn (ENS, ENS+, ENSI, and ENSI+). The addition of protease, but not inoculant, increased ivSD. Inoculation reduced pH and acetate, propionate, and ethanol concentrations, and increased lactate and total acid concentrations. In experiment 4, 8 treatments were a combination of HMC noninoculated

  9. Analysis of carbon and nitrogen forms in soil fractions after the addition of 15N-compost by 13C and 15N nuclear magnetic resonance.

    Science.gov (United States)

    Tinoco, Pilar; Almendros, Gonzalo; González-Vila, Francisco J; Lankes, Ulrich; Lüdemann, Hans-Dietrich

    2004-08-25

    A quantitative laboratory assessment of the different C and N forms in soil humus fractions was carried out by incubation of a mineral substrate after the addition of (15)N-labeled compost. The experimental design included (i) preparation of the (15)N-labeled organic matter (city refuse compost, 640 g kg(-1) wheat straw and K(15)NO(3) composted for 80 days), (ii) a further 80 day incubation of a mixture of the labeled compost with a mineral soil (32 g kg(-1)), (iii) measurement of stable isotope ratios, and (iv) isolation and structural comparison by (13)C and (15)N cross-polarization, magic-angle spinning nuclear magnetic resonance (NMR) of different organic fractions, i.e., soluble, colloidal (humic and fulvic type), and particulate (free organic matter and humin), from both the compost and the compost-treated soil. The results showed that the amide forms dominated in all of the newly formed N compounds, but an increased amount of alkali insoluble organic fractions was observed after incubation of the soil. The analysis of the insoluble, particulate fractions shows that nonextractable amides constitute the major pool of newly formed N compounds. The particulate soil fraction isolated by flotation in CHBr(3)-MeOH contained 16.8% of the total soil N and 26% of the (15)N. The (13)C NMR spectra showed that the fulvic acid-like fraction (7.6% of the soil N, 8.8% of (15)N) consisted almost completely of a C=O-containing carbohydrate material, whereas the humic acid-like fraction (20.3% of the total soil N, 8.6% of (15)N) resembled an oxidized lignoproteic fraction containing the most significant aromatic domain. The water soluble fraction was, in both soil and compost, the one with the highest isotopic abundance of (15)N (96%), but the (15)N NMR spectrum revealed minor amounts of soluble mineral N in this fraction and the remainder consisting of amide compounds.

  10. Rice Yield and the Fate of Fertilizer Nitrogen as Affected by Addition of Earthworm Casts Collected from Oilseed Rape Fields: A Pot Experiment.

    Directory of Open Access Journals (Sweden)

    Min Huang

    Full Text Available The mechanism associated with improvement of soil nutritional status by oilseed rape crop, leading to better performance of rice crop, in rice-oilseed rape cropping systems is little known. The present study was aimed to test the hypothesis that earthworm casts produced during oilseed rape-growing season have positive effects on grain yield and fertilizer nitrogen (N utilization in the subsequent flooded rice crop. A 15N-tracing pot experiment was conducted to determine the effects of earthworm casts collected from oilseed rape fields on yield attributes in rice and the fate of fertilizer N. Soil treated with earthworm casts (soil: earthworm casts = 4: 1, w/w (EC1 produced 39% higher grain yield than soil only (EC0. EC1 had 18% more panicle number and 10% higher spikelet filling percentage than EC0. Aboveground biomass and harvest index were higher in EC1 than in EC0 by 20% and 15%, respectively. SPAD values in flag leaves were 10% and 22% higher under EC1 than EC0 at 15 and 20 days after heading, respectively. EC1 had 19% higher total N uptake and 18% higher physiological N-use efficiency than EC0. These positive effects of earthworm casts on yield attributes offset negative effects of decreasing N rate from 0.74 g pot-1 (equivalent to the recommended field rate of 150 kg ha-1 to 0.44 g pot-1 (equivalent to 60% of the recommended rate. Fertilizer N retention rate was 7% higher while fertilizer N loss rate was 6% lower in EC1 than in EC0. Our study suggests that earthworm casts produced during oilseed rape-growing season are expected to have the following benefits on the subsequent flooded rice system: (1 improving growth and physiological processes in rice plants and consequently increasing rice grain yield, and (2 increasing fertilizer N retention rate and hence decreasing fertilizer N loss rate and reducing environmental risk.

  11. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

    Directory of Open Access Journals (Sweden)

    Bing Mao

    Full Text Available Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

  12. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

    Science.gov (United States)

    Mao, Bing; Mao, Rong; Zeng, De-Hui

    2017-01-01

    Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

  13. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling

    OpenAIRE

    Mao, Bing; Mao, Rong; Zeng, De-Hui

    2017-01-01

    Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N ...

  14. Update: Biological Nitrogen Fixation.

    Science.gov (United States)

    Wiseman, Alan; And Others

    1985-01-01

    Updates knowledge on nitrogen fixation, indicating that investigation of free-living nitrogen-fixing organisms is proving useful in understanding bacterial partners and is expected to lead to development of more effective symbioses. Specific areas considered include biochemistry/genetics, synthesis control, proteins and enzymes, symbiotic systems,…

  15. Nitrogen trading tool

    Science.gov (United States)

    The nitrogen cycle is impacted by human activities, including those that increase the use of nitrogen in agricultural systems, and this impact can be seen in effects such as increased nitrate (NO3) levels in groundwater or surface water resources, increased concentration of nitrous oxide (N2O) in th...

  16. Phylogenetic perspectives of nitrogen-fixing actinobacteria.

    Science.gov (United States)

    Gtari, Maher; Ghodhbane-Gtari, Faten; Nouioui, Imen; Beauchemin, Nicholas; Tisa, Louis S

    2012-01-01

    It was assumed for a long time that the ability to catalyze atmospheric nitrogen (diazotrophy) has a narrow distribution among actinobacteria being limited to the genus Frankia. Recently, the number of nitrogen fixation (nifH) genes identified in other non-Frankia actinobacteria has dramatically increased and has opened investigation on the origin and emergence of diazotrophy among actinobacteria. During the last decade, Mycobacterium flavum, Corynebacterium autotrophicum and a fluorescent Arthrobacter sp. have been reported to have nitrogenase activity, but these studies have not been further verified. Additional reports of nitrogen fixation by Agromyces, Microbacterium, Corynebacterium and Micromonospora isolated from root nodules of leguminous and actinorhizal plants have increased. For several actinobacteria, nitrogen fixation was demonstrated by the ability to grow on nitrogen-free medium, acetylene reduction activity, 15N isotope dilution analysis and identification of a nifH gene via PCR amplification. Moreover, the analyses of draft genome sequences of actinobacteria including Slackia exigua, Rothia mucilaginosa and Gordonibacter pamelaeae have also revealed the presence of nifH-like sequences. Whether these nifH sequences are associated with effective nitrogen fixation in these actinobacteria taxa has not yet been demonstrated. These genes may be vertically or horizontally transferred and be silent sequences. These ideas merit further investigation. This minireview presents a phylogenetic comparison of nitrogen fixation gene (nifH) with the aim of elucidating the processes underlying the evolutionary history of this catalytic ability among actinobacteria.

  17. Nitrogen behaviour during thermal drying of mechanically dewatered biosludge from pulp and paper industry.

    Science.gov (United States)

    Mustonen, Kati; Deviatkin, Ivan; Havukainen, Jouni; Horttanainen, Mika

    2018-04-01

    An ongoing call to implement a circular economy is underway in the European Union, and a specific attention has been placed on the forest industry, which seeks additional recycling routes for its side streams, including biosludge. Biosludge is often dried and incinerated, thus wasting the nitrogen contained therein. This paper describes a study in which the release of nitrogen during thermal drying, the impact of the drying temperatures of 130°C, 180°C, and 210°C on the mass of ammonia released, and the potential for recovery of nitrogen from biosludge were examined. The results indicate that 1310-1730 mg kgTS -1 of nitrogen was released, which corresponded to 56-74% of the soluble nitrogen in biosolids or 4.0-5.3% of the total nitrogen. Of this released nitrogen, 83-85% was identified in condensate and absorbing water, thus indicating a high potential for recovering nitrogen from biosludge.

  18. The nitrogen cycle: Atmosphere interactions

    Science.gov (United States)

    Levine, J. S.

    1984-01-01

    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  19. Adubação nitrogenada em sistema silvipastoril álamo: pastagens de inverno Nitrogen addition in a poplar silvopasture system: winter crops

    Directory of Open Access Journals (Sweden)

    Giancarlo Mira Otto

    2009-06-01

    Lam., in 2004 and 2005, submitted twice to direct grazing. The N application to the winter crop did not increase poplar growth (tree height and circumference at breast height after two years, suggesting a low residual effect of N. However, the N application promoted a linear increment of dry matter yield for both winter grazing pasture for three years. In addition, an increment of nutrient concentration in the forage was noticed, indicating an improvement in forage quality, especially N. The increment in dry matter yield and/or nutrient concentration in the winter forage increased the nutrient uptake and nutrient cycle. So, the earlier N addition to winter crop was not able to enhance poplar growth, at least in the initial years of evaluation, but the nutrient cycling and the weight gain of livestock with better pasture could bring benefits for poplar culture in the long run.

  20. Nitrogen Control in VIM Melts

    Science.gov (United States)

    Jablonski, P. D.; Hawk, J. A.

    NETL has developed a design and control philosophy for the addition of nitrogen to austenitic and ferritic steels. The design approach uses CALPHAD as the centerpiece to predict the level to which nitrogen is soluble in both the melt and the solid. Applications of this technique have revealed regions of "exclusion" in which the alloy, while within specification limits of prescribed, cannot be made by conventional melt processing. Furthermore, other investigations have found that substantial retrograde solubility of nitrogen exists, which can become problematic during subsequent melt processing and/or other finishing operations such as welding. Additionally, the CALPHAD method has been used to adjust primary melt conditions. To that end, nitrogen additions have been made using chrome nitride, silicon nitride, high-nitrogen ferrochrome as well as nitrogen gas. The advantages and disadvantages of each approach will be discussed and NETL experience in this area will be summarized with respect to steel structure.

  1. In situ sulfur isotopes (δ{sup 34}S and δ{sup 33}S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiali [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); Hu, Zhaochu, E-mail: zchu@vip.sina.com [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); The Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 102206 (China); Zhang, Wen [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); Yang, Lu [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China); National Research Council Canada, 1200 Montreal Rd., Ottawa, Ontario K1A 0R6 (Canada); Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong [State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan 430074 (China)

    2016-03-10

    The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N{sub 2} on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4–8 ml min{sup −1} nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N{sub 2} = 4 ml min{sup −1}). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d{sub 90} values of the particles in pressed powder pellets for accurate

  2. In situ sulfur isotopes (δ34S and δ33S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS

    International Nuclear Information System (INIS)

    Fu, Jiali; Hu, Zhaochu; Zhang, Wen; Yang, Lu; Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong

    2016-01-01

    The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N 2 on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4–8 ml min −1 nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N 2  = 4 ml min −1 ). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d 90 values of the particles in pressed powder pellets for accurate and precise S isotope

  3. Effect of nitrogen on the creep-fatigue behaviors of type 316L(N) stainless steel

    International Nuclear Information System (INIS)

    Kim, Dae Whan; Kim, Woo Gon; Ryu, Woo Seog

    2001-01-01

    Creep-fatigue tests including hold time of 10 minute at the maximum tensile strain were conducted for type 316(N) stainless steels containing different nitrogen content of 0.04 and 0.10 wt% at 600 .deg. C and 2x10 -3 /sec in air atmosphere. Creep-fatigue life was decreased with the hold time but was increased with the addition of nitrogen. Fracture modes were intergranular regardless of nitrogen content. Dislocation structures were changed from cell to planar with the addition of nitrogen. Carbides (M 23 C 6 ) were precipitated at grain boundaries and acted as the site for cavitation. Carbides were continuous in the low nitrogen content steel but discontinuous in high nitrogen content steel. The increase of creep-fatigue life with the addition of nitrogen is attributed to the distribution of carbides at grain boundaries rather than the change of dislocation structures

  4. A nitrogen mass balance for California

    Science.gov (United States)

    Liptzin, D.; Dahlgren, R. A.

    2010-12-01

    Human activities have greatly altered the global nitrogen cycle and these changes are apparent in water quality, air quality, ecosystem and human health. However, the relative magnitude of the sources of new reactive nitrogen and the fate of this nitrogen is not well established. Further, the biogeochemical aspects of the nitrogen cycle are often studied in isolation from the economic and social implications of all the transformations of nitrogen. The California Nitrogen Assessment is an interdisciplinary project whose aim is evaluating the current state of nitrogen science, practice, and policy in the state of California. Because of the close proximity of large population centers, highly productive and diverse agricultural lands and significant acreage of undeveloped land, California is a particularly interesting place for this analysis. One component of this assessment is developing a mass balance of nitrogen as well as identifying gaps in knowledge and quantifying uncertainty. The main inputs of new reactive nitrogen to the state are 1) synthetic nitrogen fertilizer, 2) biological nitrogen fixation, and 3) atmospheric nitrogen deposition. Permanent losses of nitrogen include 1) gaseous losses (N2, N2O, NHx, NOy), 2) riverine discharge, 3) wastewater discharge to the ocean, and 4) net groundwater recharge. A final term is the balance of food, feed, and fiber to support the human and animal populations. The largest input of new reactive nitrogen to California is nitrogen fertilizer, but both nitrogen fixation and atmospheric deposition contribute significantly. Non-fertilizer uses, such as the production of nylon and polyurethane, constitutes about 5% of the synthetic N synthesized production. The total nitrogen fixation in California is roughly equivalent on the 400,000 ha of alfalfa and the approximately 40 million ha of natural lands. In addition, even with highly productive agricultural lands, the large population of livestock, in particular dairy cows

  5. Key ecological responses to nitrogen are altered by climate ...

    Science.gov (United States)

    Here we review the effects of nitrogen and climate (e.g. temperature and precipitation) on four aspects of ecosystem structure and function including hydrologic-coupled nitrogen cycling, carbon cycling, acidification and biodiversity. Ecosystems are simultaneously exposed to multiple stressors; two dominant drivers threatening ecosystems are anthropogenic nitrogen loading and climate change. Evaluating the cumulative effects of these stressors provides a holistic view of ecosystem vulnerability, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our current knowledge of the cumulative effects of these stressors is growing, but limited. The goal of this paper is to synthesize the state of scientific knowledge on how ecosystems are affected by the interactions of meteorlogic/climatic factors (e.g., temperature and precipitation) and nitrogen addition. Understanding the interactions of meteorlogic/climatic factors and nitrogen will help to inform how current and projected variability may affect ecosystem response.

  6. How to Calculate Your Institution's Nitrogen Footprint ...

    Science.gov (United States)

    The Nitrogen Footprint Tool (NFT) allows institutions to estimate and manage their nitrogen footprint, and EPA’s Sustainable and Healthy Communities program is supporting an effort to test and expand this approach at multiple colleges, universities and institutions across the US. The growing awareness of sustainability has prompted many institutions of higher education to assess and manage their environmental impact. Many universities have programs to decrease their carbon footprint, but carbon represents just one facet of an institution’s environmental impact. Nitrogen is also important because a university’s nitrogen loss to the environment contributes to smog, soil acidification, eutrophication, biodiversity loss, the enhanced greenhouse effect, stratospheric ozone depletion, and more. The attached data template and user’s manual was based on the first NFT created for a university (University of Virginia), and tested in 6 additional institutions (including University of New Hampshire, Brown University, Eastern Mennonite University, Colorado State University). The footprint includes nitrogen released to the environment due to: 1) food consumption; 2) food production, reported by specific food categories (vegetable products, seafood, dairy and eggs, meat); 3) research animals; 4) transportation, including fleet vehicles and commuter vehicles; 5) fertilizer application; and 6) utilities, separated into electricity and heating. The data template and

  7. Nutrient co-limited Trichodesmium as nitrogen source or sink in a future ocean.

    Science.gov (United States)

    Walworth, Nathan G; Fu, Fei-Xue; Lee, Michael D; Cai, Xiaoni; Saito, Mak A; Webb, Eric A; Hutchins, David A

    2017-11-27

    Nitrogen-fixing (N 2 ) cyanobacteria provide bioavailable nitrogen to vast ocean regions but are in turn limited by iron (Fe) and/or phosphorus (P), which may force them to employ alternative nitrogen acquisition strategies. The adaptive responses of nitrogen-fixers to global-change drivers under nutrient-limited conditions could profoundly alter the current ocean nitrogen and carbon cycles. Here, we show that the globally-important N 2 -fixer Trichodesmium fundamentally shifts nitrogen metabolism towards organic-nitrogen scavenging following long-term high-CO 2 adaptation under iron and/or phosphorus (co)-limitation. Global shifts in transcripts and proteins under high CO 2 /Fe-limited and/or P-limited conditions include decreases in the N 2 -fixing nitrogenase enzyme, coupled with major increases in enzymes that oxidize trimethylamine (TMA). TMA is an abundant, biogeochemically-important organic nitrogen compound that supports rapid Trichodesmium growth while inhibiting N 2 fixation. In a future high-CO 2 ocean, this whole-cell energetic reallocation towards organic nitrogen scavenging and away from N 2 -fixation may reduce new-nitrogen inputs by Trichodesmium , while simultaneously depleting the scarce fixed-nitrogen supplies of nitrogen-limited open ocean ecosystems. Importance Trichodesmium is among the most biogeochemically-significant microorganisms in the ocean, since it supplies up to 50% of the new nitrogen supporting open ocean food webs. We used Trichodesmium cultures adapted to high CO 2 for 7 years followed by additional exposure to iron and/or phosphorus (co)-limitation. We show that 'future ocean' conditions of high CO 2 and concurrent nutrient limitation(s) fundamentally shift nitrogen metabolism away from nitrogen fixation, and instead towards upregulation of organic-nitrogen scavenging pathways. We show that Trichodesmium's responses to projected future ocean conditions include decreases in the nitrogen-fixing nitrogenase enzymes, coupled with

  8. Changes in North Atlantic nitrogen fixation controlled by ocean circulation.

    Science.gov (United States)

    Straub, Marietta; Sigman, Daniel M; Ren, Haojia; Martínez-García, Alfredo; Meckler, A Nele; Hain, Mathis P; Haug, Gerald H

    2013-09-12

    In the ocean, the chemical forms of nitrogen that are readily available for biological use (known collectively as 'fixed' nitrogen) fuel the global phytoplankton productivity that exports carbon to the deep ocean. Accordingly, variation in the oceanic fixed nitrogen reservoir has been proposed as a cause of glacial-interglacial changes in atmospheric carbon dioxide concentration. Marine nitrogen fixation, which produces most of the ocean's fixed nitrogen, is thought to be affected by multiple factors, including ocean temperature and the availability of iron and phosphorus. Here we reconstruct changes in North Atlantic nitrogen fixation over the past 160,000 years from the shell-bound nitrogen isotope ratio ((15)N/(14)N) of planktonic foraminifera in Caribbean Sea sediments. The observed changes cannot be explained by reconstructed changes in temperature, the supply of (iron-bearing) dust or water column denitrification. We identify a strong, roughly 23,000-year cycle in nitrogen fixation and suggest that it is a response to orbitally driven changes in equatorial Atlantic upwelling, which imports 'excess' phosphorus (phosphorus in stoichiometric excess of fixed nitrogen) into the tropical North Atlantic surface. In addition, we find that nitrogen fixation was reduced during glacial stages 6 and 4, when North Atlantic Deep Water had shoaled to become glacial North Atlantic intermediate water, which isolated the Atlantic thermocline from excess phosphorus-rich mid-depth waters that today enter from the Southern Ocean. Although modern studies have yielded diverse views of the controls on nitrogen fixation, our palaeobiogeochemical data suggest that excess phosphorus is the master variable in the North Atlantic Ocean and indicate that the variations in its supply over the most recent glacial cycle were dominated by the response of regional ocean circulation to the orbital cycles.

  9. Utilization of urea-nitrogen-15 in ruminants

    International Nuclear Information System (INIS)

    Boda, K.; Varady, J.; Havassy, I.

    1976-01-01

    In Merino sheep a series of experiments were carried out investigating exogenous and endogenous urea utilization. On the experimental sheep with isolated jejunum, rumen and intestine fistula, re-entral intestine cannulae, and after intra-ruminal or intra-intestinal 15 N-urea administration it was found that urea- 15 N takes part in the nitrogen recycling, and is utilized in the nitrogen pool. In experiments with synthetic protein-free diet, low protein diet and high nitrogen diet, after the intravenous administration of 15 N-urea the following findings were made: The results of experiments with synthetic diet, where the only nitrogen source was perorally (for 3-6 months) and then intravenously (for 3 months) administered urea, indicated the ability of ruminants to replace fully the nitrogen in the feed under certain conditions by increased endogenous urea recirculation. The results of the experiments with various nitrogen intakes showed that considerable amounts of urea- 15 N (44-96% from the given dose) were retained. Nitrogen compounds synthetized from blood urea- 15 N were recycled through the alimentary tract. Its secretion predominated in the forestomachs, abomasum and duodenum, and its reabsorption took place in the intestinal tract. From the 15 N incorporated into the nitrogenous substances which passed through the duodenum, 73-84% was reabsorbed. The retained 15 N was incorporated into the microbial and plasma proteins and its amide-N. On the basis of these results it is concluded that in addition to the rumeno-hepatal circulation, the entero-hepatal circulation of nitrogenous substances, including endogenous nitrogen, also plays an important role quantitatively and perhaps qualitatively in the process of re-utilizing the blood urea N for proteosynthesis and synthesis of other N-metabolites in ruminants. The hydrolysis of endogenous urea in the gastro-intestinal tract of ruminants and its utilization is a natural process indispensable for the maintenance of

  10. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Red Creek quartzite special study area, Vernal NTMS Quadrangle, Utah/Colorado, including concentrations of forty-six additional elements

    International Nuclear Information System (INIS)

    Goff, S.; George, W.E.; Apel, C.T.; Hansel, J.M.; Fuka, M.A.; Bunker, M.E.; Hanks, D.

    1981-04-01

    Totals of 22 water and 140 sediment samples were collected from 148 locations in the study area. The study area, in the north-central portion of the Vernal NTMS quadrangle, is covered by four 7-1/2' topographic maps: Dutch John, Goslin Mountain, and Clav Basin, Utah; and Willow Creek Butte, Utah/Colorado. Additional HSSR data are available for the entire Vernal quadrangle (Purson, 1980). All field and analytical data are presented in Appendix I. Figure 1 is an index and sample location map that can be used in conjunction with the 1:250,000-scale topographic map of the Vernal quadrangle (USGS, 1954). Standarized field, analytical, and data base management procedures were followed in all phases of the study. These procedures are described briefly in Appendix II-A and in reports by Sharp (1977), Hues et al (1977), Sharp and Aamodt (1978), Cheadle (1977), and Kosiewicz (1979). The data presented in Appendix I are available on magnetic tape from GJOIS Project, Union Carbide Corporation (UCC-ND), Computer Applications Department, 4500 North Building, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37830. Because this is simply a data release, intended to make the data available to the DOE and the public as quickly as possible, no discussion of the geology of the region, uranium occurrences, or data evaluation is included

  11. Identification of hardly biodegradable residuals (sulfur- and nitrogen-containing substances) during waste water treatment, including the development of analytical methods; Identifizierung von schwer abbaubaren Reststoffen (stickstoff- und schwefelhaltigen Verbindungen) bei der Abwasserbehandlung, einschliesslich analytischer Methodenentwicklung

    Energy Technology Data Exchange (ETDEWEB)

    Moehle, E.; Huber, A.; Metzger, J.W.

    1999-07-01

    Organic residuals in sewage, which are not removed completely by waste water treatment may be relevant in environmental toxicology and may disturb drinking water treatment processes. The organic residuals must be identified before new techniques to eliminate these substances from waste water can be developed and steps can be taken to prevent them from polluting waste waters. In the research project sum parameters of sulfur- and nitrogen-containing substances in municipal waste water were determined. A new method was developed to determine the organic sulfur in compounds absorbed on activated carbon (AOS). The determination of dissolved organic nitrogen (DON) was calculated as the difference between total nitrogen and the sum of NH{sub 4}{sup +}-N, NO{sub 3}{sup -}-N and NO{sub 2}{sup -}N. The removal of organic substances from the inorganic matrix was only possible for standard solutions, but not for real samples. More than 60 substances contributing to the sum parameters could be identified with GC-MS and GC-AED, an most of them could be quantified. 30-70% of the sulfur-containing substances detected with GC-AED could be identified. With the GC-MS screening method 21 drugs or drug metabolites could be identified and partly quantified. Hydrophilic organic residuals were identified and quantified with high performance liquid chromatography coupled with UV- and fluorescence detectors and also with a mass detector (ESI-MS-MS). With the methods described only a small percentage of the sum of AOS and DON could be detected, although new materials for the solid phase enrichment and new analytical methods, such as HPLC-MS-MS were used. In order to get information about the degree of elimination (absorption or degradation) of different drugs in a municipal sewage plant, laboratory-scale tests under aerobic conditions were performed. A batch reactor containing drugs in environmentally relevant concentrations and a suspension of activated sludge was coupled online with HPLC

  12. Synthesis and review: Tackling the nitrogen management challenge: from global to local scales

    Science.gov (United States)

    Reis, Stefan; Bekunda, Mateete; Howard, Clare M.; Karanja, Nancy; Winiwarter, Wilfried; Yan, Xiaoyuan; Bleeker, Albert; Sutton, Mark A.

    2016-12-01

    One of the ‘grand challenges’ of this age is the anthropogenic impact exerted on the nitrogen cycle. Issues of concern range from an excess of fixed nitrogen resulting in environmental pressures for some regions, while for other regions insufficient fixed nitrogen affects food security and may lead to health risks. To address these issues, nitrogen needs to be managed in an integrated fashion, at a variety of scales (from global to local). Such management has to be based on a thorough understanding of the sources of reactive nitrogen released into the environment, its deposition and effects. This requires a comprehensive assessment of the key drivers of changes in the nitrogen cycle both spatially, at the field, regional and global scale and over time. In this focus issue, we address the challenges of managing reactive nitrogen in the context of food production and its impacts on human and ecosystem health. In addition, we discuss the scope for and design of management approaches in regions with too much and too little nitrogen. This focus issue includes several contributions from authors who participated at the N2013 conference in Kampala in November 2013, where delegates compiled and agreed upon the ‘Kampala Statement-for-Action on Reactive Nitrogen in Africa and Globally’. These contributions further underline scientifically the claims of the ‘Kampala Statement’, that simultaneously reducing pollution and increasing nitrogen available in the food system, by improved nitrogen management offers win-wins for environment, health and food security in both developing and developed economies. The specific messages conveyed in the Kampala Statement focus on improving nitrogen management (I), including the reduction of nitrogen losses from agriculture, industry, transport and energy sectors, as well as improving waste treatment and informing individuals and institutions (II). Highlighting the need for innovation and increased awareness among stakeholders (III

  13. Mineral commodity profiles: nitrogen

    Science.gov (United States)

    Kramer, Deborah A.

    2004-01-01

    Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

  14. Experimental and numerical investigations on nitrogen species ...

    Indian Academy of Sciences (India)

    ... the peak nitrate nitrogen concentration of 1,620 mg/l is observed at first day due to high permeability and high soil background nitrogen concentration. Additionally, the model results show that the application of high nitrogen content wastewater for irrigation in Ludhiana soil will affect the groundwater quality even when the ...

  15. Nitrogen balance of healthy Dutch women before and during pregnancy

    NARCIS (Netherlands)

    Mojtahedi, M.; Groot, de C.P.G.M.; Boekholt, H.A.; Raaij, van J.M.A.

    2002-01-01

    Background: Experimental studies including longitudinal nitrogen balance studies could provide insight into protein metabolism in pregnancy. Objective: Our aim was to determine the development of nitrogen balance during pregnancy compared with nitrogen balance before pregnancy in women consuming

  16. The Additive Value of Femoral Ultrasound for Subclinical Atherosclerosis Assessment in a Single Center Cohort of 962 Adults, Including High Risk Patients with Rheumatoid Arthritis, Human Immunodeficiency Virus Infection and Type 2 Diabetes Mellitus

    NARCIS (Netherlands)

    Protogerou, A.D.; Fransen, J.; Zampeli, E.; Argyris, A.A.; Aissopou, E.; Arida, A.; Konstantonis, G.D.; Tentolouris, N.; Makrilakis, K.; Psichogiou, M.; Daikos, G.; Kitas, G.D.; Sfikakis, P.P.

    2015-01-01

    BACKGROUND: Presence of femoral atheromatic plaques, an emerging cardiovascular disease (CVD) biomarker additional to carotid plaques, is poorly investigated in conditions associating with accelerated atherosclerosis such as Rheumatoid Arthritis (RA), Human Immunodeficiency Virus (HIV) infection and

  17. Measurement of toverline{t} production with additional jet activity, including b quark jets, in the dilepton decay channel using pp collisions at √{s} = 8 {TeV}

    Science.gov (United States)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; de Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; van de Klundert, M.; van Haevermaet, H.; van Mechelen, P.; van Remortel, N.; van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; de Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; van Doninck, W.; van Mulders, P.; van Onsem, G. P.; van Parijs, I.; Barria, P.; Brun, H.; Caillol, C.; Clerbaux, B.; de Lentdecker, G.; Fasanella, G.; Favart, L.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Marinov, A.; Perniè, L.; Randle-Conde, A.; Reis, T.; Seva, T.; Vander Velde, C.; Yonamine, R.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; McCartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva, S.; Sigamani, M.; Strobbe, N.; Tytgat, M.; van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; Ceard, L.; da Silveira, G. G.; Delaere, C.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Musich, M.; Nuttens, C.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Hammad, G. H.; Júnior, W. L. Aldá; Alves, F. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Hamer, M.; Hensel, C.; Mora Herrera, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; da Costa, E. M.; de Jesus Damiao, D.; de Oliveira Martins, C.; Fonseca de Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; de Souza Santos, A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Micanovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; El Sawy, M.; El-Khateeb, E.; Elkafrawy, T.; Mohamed, A.; Salama, E.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Dahms, T.; Davignon, O.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.

    2016-07-01

    Jet multiplicity distributions in top quark pair ({t}{overline{t}}) events are measured in pp collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC using a data set corresponding to an integrated luminosity of 19.7 {fb}^ {-1}. The measurement is performed in the dilepton decay channels (e^+e^-, μ^+ μ^-, and e^{±} μ^{∓}). The absolute and normalized differential cross sections for {t}overline{t} production are measured as a function of the jet multiplicity in the event for different jet transverse momentum thresholds and the kinematic properties of the leading additional jets. The differential {t overline{t} b} and {t overline{t} b overline{b}} cross sections are presented for the first time as a function of the kinematic properties of the leading additional b jets. Furthermore, the fraction of events without additional jets above a threshold is measured as a function of the transverse momenta of the leading additional jets and the scalar sum of the transverse momenta of all additional jets. The data are compared and found to be consistent with predictions from several perturbative quantum chromodynamics event generators and a next-to-leading order calculation.

  18. Nitrogen tank

    CERN Multimedia

    2006-01-01

    Wanted The technical file about the pressure vessel RP-270 It concerns the Nitrogen tank, 60m3, 22 bars, built in 1979, and installed at Point-2 for the former L3 experiment. If you are in possession of this file, or have any files about an equivalent tank (probably between registered No. RP-260 and -272), please contact Marc Tavlet, the ALICE Glimos.

  19. Measurement of $\\mathrm{ t \\bar{t} } $ production with additional jet activity, including b quark jets, in the dilepton decay channel using pp collisions at $\\sqrt{s} =$ 8 TeV

    CERN Document Server

    Khachatryan, Vardan; Tumasyan, Armen; Adam, Wolfgang; Aşılar, Ece; Bergauer, Thomas; Brandstetter, Johannes; Brondolin, Erica; Dragicevic, Marko; Erö, Janos; Flechl, Martin; Friedl, Markus; Fruehwirth, Rudolf; Ghete, Vasile Mihai; Hartl, Christian; Hörmann, Natascha; Hrubec, Josef; Jeitler, Manfred; Knünz, Valentin; König, Axel; Krammer, Manfred; Krätschmer, Ilse; Liko, Dietrich; Matsushita, Takashi; Mikulec, Ivan; Rabady, Dinyar; Rahbaran, Babak; Rohringer, Herbert; Schieck, Jochen; Schöfbeck, Robert; Strauss, Josef; Treberer-Treberspurg, Wolfgang; Waltenberger, Wolfgang; Wulz, Claudia-Elisabeth; Mossolov, Vladimir; Shumeiko, Nikolai; Suarez Gonzalez, Juan; Alderweireldt, Sara; Cornelis, Tom; De Wolf, Eddi A; Janssen, Xavier; Knutsson, Albert; Lauwers, Jasper; Luyckx, Sten; Van De Klundert, Merijn; Van Haevermaet, Hans; Van Mechelen, Pierre; Van Remortel, Nick; Van Spilbeeck, Alex; Abu Zeid, Shimaa; Blekman, Freya; D'Hondt, Jorgen; Daci, Nadir; De Bruyn, Isabelle; Deroover, Kevin; Heracleous, Natalie; Keaveney, James; Lowette, Steven; Moreels, Lieselotte; Olbrechts, Annik; Python, Quentin; Strom, Derek; Tavernier, Stefaan; Van Doninck, Walter; Van Mulders, Petra; Van Onsem, Gerrit Patrick; Van Parijs, Isis; Barria, Patrizia; Brun, Hugues; Caillol, Cécile; Clerbaux, Barbara; De Lentdecker, Gilles; Fasanella, Giuseppe; Favart, Laurent; Grebenyuk, Anastasia; Karapostoli, Georgia; Lenzi, Thomas; Léonard, Alexandre; Maerschalk, Thierry; Marinov, Andrey; Perniè, Luca; Randle-conde, Aidan; Reis, Thomas; Seva, Tomislav; Vander Velde, Catherine; Vanlaer, Pascal; Yonamine, Ryo; Zenoni, Florian; Zhang, Fengwangdong; Beernaert, Kelly; Benucci, Leonardo; Cimmino, Anna; Crucy, Shannon; Dobur, Didar; Fagot, Alexis; Garcia, Guillaume; Gul, Muhammad; Mccartin, Joseph; Ocampo Rios, Alberto Andres; Poyraz, Deniz; Ryckbosch, Dirk; Salva Diblen, Sinem; Sigamani, Michael; Strobbe, Nadja; Tytgat, Michael; Van Driessche, Ward; Yazgan, Efe; Zaganidis, Nicolas; Basegmez, Suzan; Beluffi, Camille; Bondu, Olivier; Brochet, Sébastien; Bruno, Giacomo; Caudron, Adrien; Ceard, Ludivine; Da Silveira, Gustavo Gil; Delaere, Christophe; Favart, Denis; Forthomme, Laurent; Giammanco, Andrea; Hollar, Jonathan; Jafari, Abideh; Jez, Pavel; Komm, Matthias; Lemaitre, Vincent; Mertens, Alexandre; Musich, Marco; Nuttens, Claude; Perrini, Lucia; Pin, Arnaud; Piotrzkowski, Krzysztof; Popov, Andrey; Quertenmont, Loic; Selvaggi, Michele; Vidal Marono, Miguel; Beliy, Nikita; Hammad, Gregory Habib; Aldá Júnior, Walter Luiz; Alves, Fábio Lúcio; Alves, Gilvan; Brito, Lucas; Correa Martins Junior, Marcos; Hamer, Matthias; Hensel, Carsten; Mora Herrera, Clemencia; Moraes, Arthur; Pol, Maria Elena; Rebello Teles, Patricia; Belchior Batista Das Chagas, Ewerton; Carvalho, Wagner; Chinellato, Jose; Custódio, Analu; Melo Da Costa, Eliza; De Jesus Damiao, Dilson; De Oliveira Martins, Carley; Fonseca De Souza, Sandro; Huertas Guativa, Lina Milena; Malbouisson, Helena; Matos Figueiredo, Diego; Mundim, Luiz; Nogima, Helio; Prado Da Silva, Wanda Lucia; Santoro, Alberto; Sznajder, Andre; Tonelli Manganote, Edmilson José; Vilela Pereira, Antonio; Ahuja, Sudha; Bernardes, Cesar Augusto; De Souza Santos, Angelo; Dogra, Sunil; Tomei, Thiago; De Moraes Gregores, Eduardo; Mercadante, Pedro G; Moon, Chang-Seong; Novaes, Sergio F; Padula, Sandra; Romero Abad, David; Ruiz Vargas, José Cupertino; Aleksandrov, Aleksandar; Hadjiiska, Roumyana; Iaydjiev, Plamen; Rodozov, Mircho; Stoykova, Stefka; Sultanov, Georgi; Vutova, Mariana; Dimitrov, Anton; Glushkov, Ivan; Litov, Leander; Pavlov, Borislav; Petkov, Peicho; Ahmad, Muhammad; Bian, Jian-Guo; Chen, Guo-Ming; Chen, He-Sheng; Chen, Mingshui; Cheng, Tongguang; Du, Ran; Jiang, Chun-Hua; Plestina, Roko; Romeo, Francesco; Shaheen, Sarmad Masood; Spiezia, Aniello; Tao, Junquan; Wang, Chunjie; Wang, Zheng; Zhang, Huaqiao; Asawatangtrakuldee, Chayanit; Ban, Yong; Li, Qiang; Liu, Shuai; Mao, Yajun; Qian, Si-Jin; Wang, Dayong; Xu, Zijun; Avila, Carlos; Cabrera, Andrés; Chaparro Sierra, Luisa Fernanda; Florez, Carlos; Gomez, Juan Pablo; Gomez Moreno, Bernardo; Sanabria, Juan Carlos; Godinovic, Nikola; Lelas, Damir; Puljak, Ivica; Ribeiro Cipriano, Pedro M; Antunovic, Zeljko; Kovac, Marko; Brigljevic, Vuko; Kadija, Kreso; Luetic, Jelena; Micanovic, Sasa; Sudic, Lucija; Attikis, Alexandros; Mavromanolakis, Georgios; Mousa, Jehad; Nicolaou, Charalambos; Ptochos, Fotios; Razis, Panos A; Rykaczewski, Hans; Bodlak, Martin; Finger, Miroslav; Finger Jr, Michael; El Sawy, Mai; El-khateeb, Esraa; Elkafrawy, Tamer; Mohamed, Amr

    2016-07-07

    Jet multiplicity distributions in top quark pair ($ \\mathrm{ t \\bar{t} } $) events are measured in pp collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC using a data set corresponding to an integrated luminosity of 19.7 fb$^{-1}$. The measurement is performed in the dilepton decay channels ($ \\mathrm{ e^{+} e^{-} }$, $\\mu^{+} \\mu^{-} $, and $\\mathrm{ e^{\\pm} } \\mu^{\\mp} $). The absolute and normalized differential cross sections for $ \\mathrm{ t \\bar{t} } $ production are measured as a function of the jet multiplicity in the event for different jet transverse momentum thresholds and the kinematic properties of the leading additional jets. The differential $ \\mathrm{ t \\bar{t} b} $ and $ \\mathrm{ t \\bar{t} b \\bar{b} } $ cross sections are presented for the first time as a function of the kinematic properties of the leading additional b jets. Furthermore, the fraction of events without additional jets above a threshold is measured as a function of the transverse momenta of the leadi...

  20. A forma de aplicação da uréia e dos resíduos vegetais afeta a disponibilidade de nitrogênio The addition form of crop residues and urea interfers on nitrogen availability

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Ernani

    2005-04-01

    Full Text Available O método de aplicação dos resíduos vegetais e dos fertilizantes nitrogenados pode afetar as reações do nitrogênio no solo, principalmente no plantio direto. O presente trabalho objetivou avaliar esses efeitos na disponibilidade de N para o milho em dois solos, em casa-de-vegetação. Combinações de métodos (ausência, incorporada ou na superfície de adição de palha de aveia (0,4kg m-2 e uréia (50mg N kg-1 foram aplicadas em unidades experimentais (7dm³ vaso-1 de dois solos, perfazendo um fatorial 3 x 3 x 2. O milho foi semeado no dia da aplicação dos tratamentos e as plantas foram cultivadas durante trinta dias, sobre um Neossolo e um Nitossolo, respectivamente com 50 e 520g kg-1 de argila e 8 e 48g kg-1 de matéria orgânica. A aplicação de palha de aveia, principalmente sobre a superfície do solo, beneficiou o desenvolvimento das plantas, possivelmente pela manutenção de maior quantidade de umidade nos solos. A aplicação de uréia não afetou nenhum parâmetro vegetal no solo argiloso, talvez porque a decomposição da matéria orgânica liberou mais N do que a imobilização ocasionada durante a decomposição da palha; no solo arenoso, entretanto, a uréia foi benéfica quando incorporada ao solo, e prejudicial quando adicionada na superfície, provavelmente devido à toxidez de amônia. Dessa forma, o efeito da decomposição da palha de aveia na disponibilidade de N foi função do teor de matéria orgânica original do solo.Management of both crop residues and nitrogen fertilizers affects soil N reactions especially on no-till systems. The magnitude of these effects on N availability to maize was evaluated in a greenhouse study. Combinations of oat straw and urea (absence, soil incorporated or surface applied were added to experimental units (7-dm³ per pot of two soils, in a 3 x 3 x 2 factorial combination. Plants were sown just following treatments addition, and grown for thirty days in two soils (Typic

  1. Evaluation of certain food additives.

    Science.gov (United States)

    2015-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, and to prepare specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for eight food additives (Benzoe tonkinensis; carrageenan; citric and fatty acid esters of glycerol; gardenia yellow; lutein esters from Tagetes erecta; octenyl succinic acid-modified gum arabic; octenyl succinic acid-modified starch; paprika extract; and pectin) and eight groups of flavouring agents (aliphatic and alicyclic hydrocarbons; aliphatic and aromatic ethers; ionones and structurally related substances; miscellaneous nitrogen-containing substances; monocyclic and bicyclic secondary alcohols, ketones and related esters; phenol and phenol derivatives; phenyl-substituted aliphatic alcohols and related aldehydes and esters; and sulfur-containing heterocyclic compounds). Specifications for the following food additives were revised: citric acid; gellan gum; polyoxyethylene (20) sorbitan monostearate; potassium aluminium silicate; and Quillaia extract (Type 2). Annexed to the report are tables summarizing the Committee's recommendations for dietary exposures to and toxicological evaluations of all of the food additives and flavouring agents considered at this meeting.

  2. Interactive Effects of Nitrogen and Climate Change on Biodiversity

    Science.gov (United States)

    Porter, E. M.; Bowman, W. D.; Clark, C. M.; Compton, J. E.; Pardo, L. H.; Soong, J.

    2011-12-01

    Biodiversity has been described as the diversity of life on earth within species, between species and in ecosystems. Biodiversity contributes to regulating ecosystem services like climate, flood, disease, and water quality regulation. Biodiversity also supports and sustains ecosystem services that provide material goods like food, fiber, fuel, timber and water, and to non-material benefits like educational, recreational, spiritual, and aesthetic ecosystem services. The Millennium Ecosystem Assessment estimated that the rate of biodiversity loss due to human activity in the last 50 years has been more rapid than at any other time in human history, and that many of the drivers of biodiversity loss are increasing. The strongest drivers of biodiversity loss include habitat loss, overexploitation, invasive species, climate change, and pollution, including pollution from reactive nitrogen. Of these stressors, climate change and reactive nitrogen from anthropogenic activities are causing some of the most rapid changes. Climate change is causing warming trends that result in consistent patterns of poleward and elevational range shifts of flora and fauna, causing changes in biodiversity. Warming has also resulted in changes in phenology, particularly the earlier onset of spring events, migration, and lengthening of the growing season, disrupting predator-prey and plant-pollinator interactions. In addition to warming, elevated carbon dioxide by itself can affect biodiversity by influencing plant growth, soil water, tissue stoichiometry, and trophic interactions. Nitrogen enrichment also impacts ecosystems and biodiversity in a variety of ways. Nitrogen enhances plant growth, but has been shown to favor invasive, fast-growing species over native species adapted to low nitrogen conditions. Although there have been a limited number of empirical studies on climate change and nitrogen interactions, inferences can be drawn from observed responses to each stressor by itself. For

  3. Total Nitrogen in Surface Water

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALN is reported in kilograms/hectare/year. More information about these resources, including the...

  4. The Additive Value of Femoral Ultrasound for Subclinical Atherosclerosis Assessment in a Single Center Cohort of 962 Adults, Including High Risk Patients with Rheumatoid Arthritis, Human Immunodeficiency Virus Infection and Type 2 Diabetes Mellitus.

    Directory of Open Access Journals (Sweden)

    Athanasios D Protogerou

    Full Text Available Presence of femoral atheromatic plaques, an emerging cardiovascular disease (CVD biomarker additional to carotid plaques, is poorly investigated in conditions associating with accelerated atherosclerosis such as Rheumatoid Arthritis (RA, Human Immunodeficiency Virus (HIV infection and Type 2 Diabetes Mellitus (T2DM.To assess the frequency of femoral/carotid subclinical atheromatosis phenotypes in RA, HIV and T2DM and search for each disease-specific probability of either femoral and/or carotid subclinical atheromatosis, we examined by ultrasound a single-center cohort of CVD-free individuals comprised of consecutive non-diabetic patients with RA (n=226 and HIV (n=133, T2DM patients (n=109 and non-diabetic individuals with suspected/known hypertension (n=494 who served as reference group.Subclinical atheromatosis--defined as local plaque presence in at least on arterial bed--was diagnosed in 50% of the overall population. Among them, femoral plaques only were found in 25% of either RA or HIV patients, as well as in 16% of T2DM patients and 35% of reference subjects. After adjusting for all classical CVD risk factors, RA and HIV patients had comparable probability to reference group of having femoral plaques, but higher probability (1.75; 1.17-2.63 (odds ratio; 95% confidence intervals, 2.04; 1.14-3.64, respectively of having carotid plaques, whereas T2DM patients had higher probability to have femoral and carotid plaques, albeit, due to their pronounced dyslipidemic profile.RA and HIV accelerate predominantly carotid than femoral. A "two windows" carotid/femoral, rather than carotid alone ultrasound, screening improves substantially subclinical atheromatosis detection in patients at high CVD risk.

  5. Human Decisions: Nitrogen Footprints and Environmental Effects

    Science.gov (United States)

    Leach, A. M.; Bleeker, A.; Galloway, J. N.; Erisman, J.

    2012-12-01

    Human consumption choices are responsible for growing losses of reactive nitrogen (Nr) to the environment. Once in the environment, Nr can cause a cascade of negative impacts such as smog, acid rain, coastal eutrophication, climate change, and biodiversity loss. Although all humans must consume nitrogen as protein, the food production process releases substantial Nr to the environment. This dilemma presents a challenge: how do we feed a growing population while reducing Nr? Although top-down strategies to reduce Nr losses (e.g., emissions controls) are necessary, the bottom-up strategies focusing on personal consumption patterns will be imperative to solve the nitrogen challenge. Understanding the effects of different personal choices on Nr losses and the environment is an important first step for this strategy. This paper will utilize information and results from the N-Calculator, a per capita nitrogen footprint model (www.N-Print.org), to analyze the impact of different food consumption patterns on a personal food nitrogen footprint and the environment. Scenarios will analyze the impact of the following dietary patterns on the average United States (28 kg Nr/cap/yr) food nitrogen footprint: 1) Consuming only the recommended protein as defined by the WHO and the USDA; 2) Reducing food waste by 50%; 3) Consuming a vegetarian diet; 4) Consuming a vegan diet; 5) Consuming a demitarian diet (replacing half of animal protein consumption with vegetable protein); 6) Substituting chicken (a more efficient animal protein) with beef (a less efficient animal protein); 7) Consuming sustainably-produced food; and 8) Using advanced wastewater treatment. Preliminary results suggest that widespread advanced wastewater treatment with nutrient removal technology and halving food waste would each reduce the US personal food nitrogen footprint by 13%. In addition, reducing protein consumption to the recommended levels would reduce the footprint by about 42%. Combining these measures

  6. Effects of increased soil nitrogen on the dominance of alien annual plants in the Mojave Desert

    Science.gov (United States)

    Brooks, Matthew L.

    2003-01-01

    1. Deserts are one of the least invaded ecosystems by plants, possibly due to naturally low levels of soil nitrogen. Increased levels of soil nitrogen caused by atmospheric nitrogen deposition may increase the dominance of invasive alien plants and decrease the diversity of plant communities in desert regions, as it has in other ecosystems. Deserts should be particularly susceptible to even small increases in soil nitrogen levels because the ratio of increased nitrogen to plant biomass is higher compared with most other ecosystems.2. The hypothesis that increased soil nitrogen will lead to increased dominance by alien plants and decreased plant species diversity was tested in field experiments using nitrogen additions at three sites in the in the Mojave Desert of western North America.3. Responses of alien and native annual plants to soil nitrogen additions were measured in terms of density, biomass and species richness. Effects of nitrogen additions were evaluated during 2 years of contrasting rainfall and annual plant productivity. The rate of nitrogen addition was similar to published rates of atmospheric nitrogen deposition in urban areas adjacent to the Mojave Desert (3·2 g N m−2 year−1). The dominant alien species included the grasses Bromus madritensis ssp. rubens and Schismus spp. (S. arabicus and S. barbatus) and the forb Erodium cicutarium.4. Soil nitrogen addition increased the density and biomass of alien annual plants during both years, but decreased density, biomass and species richness of native species only during the year of highest annual plant productivity. The negative response of natives may have been due to increased competitive stress for soil water and other nutrients caused by the increased productivity of aliens.5. The effects of nitrogen additions were significant at both ends of a natural nutrient gradient, beneath creosote bush Larrea tridentata canopies and in the interspaces between them, although responses varied among

  7. The Global Nitrogen Cycle

    Science.gov (United States)

    Galloway, J. N.

    2003-12-01

    Once upon a time nitrogen did not exist. Today it does. In the intervening time the universe was formed, nitrogen was created, the Earth came into existence, and its atmosphere and oceans were formed! In this analysis of the Earth's nitrogen cycle, I start with an overview of these important events relative to nitrogen and then move on to the more traditional analysis of the nitrogen cycle itself and the role of humans in its alteration.The universe is ˜15 Gyr old. Even after its formation, there was still a period when nitrogen did not exist. It took ˜300 thousand years after the big bang for the Universe to cool enough to create atoms; hydrogen and helium formed first. Nitrogen was formed in the stars through the process of nucleosynthesis. When a star's helium mass becomes great enough to reach the necessary pressure and temperature, helium begins to fuse into still heavier elements, including nitrogen.Approximately 10 Gyr elapsed before Earth was formed (˜4.5 Ga (billion years ago)) by the accumulation of pre-assembled materials in a multistage process. Assuming that N2 was the predominate nitrogen species in these materials and given that the temperature of space is -270 °C, N2 was probably a solid when the Earth was formed since its boiling point (b.p.) and melting point (m.p.) are -196 °C and -210 °C, respectively. Towards the end of the accumulation period, temperatures were probably high enough for significant melting of some of the accumulated material. The volcanic gases emitted by the resulting volcanism strongly influenced the surface environment. Nitrogen was converted from a solid to a gas and emitted as N2. Carbon and sulfur were probably emitted as CO and H2S (Holland, 1984). N2 is still the most common nitrogen volcanic gas emitted today at a rate of ˜2 TgN yr-1 (Jaffee, 1992).Once emitted, the gases either remained in the atmosphere or were deposited to the Earth's surface, thus continuing the process of biogeochemical cycling. The rate of

  8. Enzymology and ecology of the nitrogen cycle.

    Science.gov (United States)

    Martínez-Espinosa, Rosa María; Cole, Jeffrey A; Richardson, David J; Watmough, Nicholas J

    2011-01-01

    The nitrogen cycle describes the processes through which nitrogen is converted between its various chemical forms. These transformations involve both biological and abiotic redox processes. The principal processes involved in the nitrogen cycle are nitrogen fixation, nitrification, nitrate assimilation, respiratory reduction of nitrate to ammonia, anaerobic ammonia oxidation (anammox) and denitrification. All of these are carried out by micro-organisms, including bacteria, archaea and some specialized fungi. In the present article, we provide a brief introduction to both the biochemical and ecological aspects of these processes and consider how human activity over the last 100 years has changed the historic balance of the global nitrogen cycle.

  9. Forest fuel reduces the nitrogen load

    International Nuclear Information System (INIS)

    Lundborg, A.

    1993-03-01

    A study of the literature was made on the basis of the following hypothesis: ''If nitrogen-rich felling residues are removed from the forest, the nitrogen load on the forest ecosystem is decreased and the risk of nitrogen saturation also decreases''. The study was designed to provide information on how the nitrogen situation is influenced if felling residues are removed from nitrogen-loaded forests and used as fuel. Felling residues release very little nitrogen during the first years after felling. They can immobilize nitrogen from the surroundings, make up a considerable addition to the nitrogen store in the soil, but also release nitrogen in later stages of degradation. The slash has an influence on the soil climate and thus on soil processes. Often there is an increase in the mineralization of litter and humus below the felling residues. At the same time, nitrification is favoured, particularly if the slash is left in heaps. Felling residues contain easily soluble nutrients that stimulate the metabolization of organic matter that otherwise is rather resistant to degradation. The slash also inhibits the clear-cut vegetation and its uptake of nitrogen. These effects result in increased leaching of nitrogen and minerals if the felling residues are left on the site. (99 refs.)

  10. Nitrogen uptake and assimilation in proliferating embryogenic cultures of Norway spruce-Investigating the specific role of glutamine.

    Directory of Open Access Journals (Sweden)

    Johanna Carlsson

    Full Text Available Somatic embryogenesis is an in vitro system employed for plant propagation and the study of embryo development. Nitrogen is essential for plant growth and development and, hence, the production of healthy embryos during somatic embryogenesis. Glutamine has been shown to increase plant biomass in many in vitro applications, including somatic embryogenesis. However, several aspects of nitrogen nutrition during somatic embryogenesis remain unclear. Therefore, we investigated the uptake and assimilation of nitrogen in Norway spruce pro-embryogenic masses to elucidate some of these aspects. In our study, addition of glutamine had a more positive effect on growth than inorganic nitrogen. The nitrogen uptake appeared to be regulated, with a strong preference for glutamine; 67% of the assimilated nitrogen in the free amino acid pool originated from glutamine-nitrogen. Glutamine addition also relieved the apparently limited metabolism (as evidenced by the low concentration of free amino acids of pro-embryogenic masses grown on inorganic nitrogen only. The unusually high alanine concentration in the presence of glutamine, suggests that alanine biosynthesis was involved in alleviating these constraints. These findings inspire further studies of nitrogen nutrition during the somatic embryogenesis process; identifying the mechanism(s that govern glutamine enhancement of pro-embryogenic masses growth is especially important in this regard.

  11. Food additives

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002435.htm Food additives To use the sharing features on this page, please enable JavaScript. Food additives are substances that become part of a food ...

  12. Potential nitrogen critical loads for northern Great Plains grassland vegetation

    Science.gov (United States)

    Symstad, Amy J.; Smith, Anine T.; Newton, Wesley E.; Knapp, Alan K.

    2015-01-01

    The National Park Service is concerned that increasing atmospheric nitrogen deposition caused by fossil fuel combustion and agricultural activities could adversely affect the northern Great Plains (NGP) ecosystems in its trust. The critical load concept facilitates communication between scientists and policy makers or land managers by translating the complex effects of air pollution on ecosystems into concrete numbers that can be used to inform air quality targets. A critical load is the exposure level below which significant harmful effects on sensitive elements of the environment do not occur. A recent review of the literature suggested that the nitrogen critical load for Great Plains vegetation is 10-25 kg N/ha/yr. For comparison, current atmospheric nitrogen deposition in NGP National Park Service (NPS) units ranges from ~4 kg N/ha/yr in the west to ~13 kg N/ha/yr in the east. The suggested critical load, however, was derived from studies far outside of the NGP, and from experiments investigating nitrogen loads substantially higher than current atmospheric deposition in the region.Therefore, to better determine the nitrogen critical load for sensitive elements in NGP parks, we conducted a four-year field experiment in three northern Great Plains vegetation types at Badlands and Wind Cave National Parks. The vegetation types were chosen because of their importance in NGP parks, their expected sensitivity to nitrogen addition, and to span a range of natural fertility. In the experiment, we added nitrogen at rates ranging from below current atmospheric deposition (2.5 kg N/ha/yr) to far above those levels but commensurate with earlier experiments (100 kg N/ha/yr). We measured the response of a variety of vegetation and soil characteristics shown to be sensitive to nitrogen addition in other studies, including plant biomass production, plant tissue nitrogen concentration, plant species richness and composition, non-native species abundance, and soil inorganic

  13. Nitrogen uptake by phytoplankton and zooxanthellae in a coral atoll

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar, M.V.M.; Devassy, V.P.; Slawyk, G.; Goes, J.I.; Jayakumar, D.A.; Rajendran, A.

    of the Lakshadweep Archipelago (Indian Ocean). This paper also presents the ambient concentrations of these nitrogenous nutrients in the lagoon and surrounding waters. In addition, the excretion of these nitrogen compounds by major coral species of the atoll was also...

  14. POPULATION DYNAMICS OF SMALL MAMMALS ACROSS A NITROGEN AMENDED LANDSCAPE

    Science.gov (United States)

    Biogeochemical alterations of the nitrogen cycle from anthropogenic activities could have significant effects on ecological processes at the population, community and ecosystem levels. Nitrogen additions in grasslands have produced qualitative and quantitative changes in vegetat...

  15. Infrared spectroscopic monitoring of urea addition to oriented strandboard resins

    Science.gov (United States)

    Chi-Leung So; Thomas L. Eberhardt; Ernest Hsu; Brian K. Via; Chung Y. Hse

    2007-01-01

    One of the variables in phenol formaldehyde adhesive resin formulation is the addition of urea, which allows the resin manufacturer to manipulate both product functionality and cost. Nitrogen content can be used as a measure of the level of urea addition because most of the nitrogen present is derived from urea added at the end of the preparation process. Nitrogen...

  16. New approaches for description of nitrogen chemistry in combustion

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Kilpinen, P.; Brink, A.; Norstroem, T. [Aabo Akademi, Turku (Finland)

    1996-12-01

    The aim of the project is to develop novel models for a more accurate description of nitrogen oxide emissions from combustion processes and to increase the understanding of the complex details of homogeneous nitrogen reactions in combustion and gasification. The topics dealt with during 1995 include: (1) effect of Cl on CO oxidation and nitrogen reactions, (2) effect of pressure on NO reduction by SNCR (in co-operation with the project 204), (3) NH{sub 3} conversion to N{sub 2} in gasification gases by selective oxidation (in cooperation with the project 203). In addition, a literature review of the models suggested for the interaction between turbulence and a chemical gas-phase reaction has been made. A commercial CFD code, FLUENT, has also been taken into use. (author)

  17. Quorum sensing in nitrogen-fixing rhizobia.

    Science.gov (United States)

    González, Juan E; Marketon, Melanie M

    2003-12-01

    Members of the rhizobia are distinguished for their ability to establish a nitrogen-fixing symbiosis with leguminous plants. While many details of this relationship remain a mystery, much effort has gone into elucidating the mechanisms governing bacterium-host recognition and the events leading to symbiosis. Several signal molecules, including plant-produced flavonoids and bacterially produced nodulation factors and exopolysaccharides, are known to function in the molecular conversation between the host and the symbiont. Work by several laboratories has shown that an additional mode of regulation, quorum sensing, intercedes in the signal exchange process and perhaps plays a major role in preparing and coordinating the nitrogen-fixing rhizobia during the establishment of the symbiosis. Rhizobium leguminosarum, for example, carries a multitiered quorum-sensing system that represents one of the most complex regulatory networks identified for this form of gene regulation. This review focuses on the recent stream of information regarding quorum sensing in the nitrogen-fixing rhizobia. Seminal work on the quorum-sensing systems of R. leguminosarum bv. viciae, R. etli, Rhizobium sp. strain NGR234, Sinorhizobium meliloti, and Bradyrhizobium japonicum is presented and discussed. The latest work shows that quorum sensing can be linked to various symbiotic phenomena including nodulation efficiency, symbiosome development, exopolysaccharide production, and nitrogen fixation, all of which are important for the establishment of a successful symbiosis. Many questions remain to be answered, but the knowledge obtained so far provides a firm foundation for future studies on the role of quorum-sensing mediated gene regulation in host-bacterium interactions.

  18. Nitrogen in germanium

    Science.gov (United States)

    Chambouleyron, I.; Zanatta, A. R.

    1998-07-01

    The known properties of nitrogen as an impurity in, and as an alloy element of, the germanium network are reviewed in this article. Amorphous and crystalline germanium-nitrogen alloys are interesting materials with potential applications for protective coatings and window layers for solar conversion devices. They may also act as effective diffusion masks for III-V electronic devices. The existing data are compared with similar properties of other group IV nitrides, in particular with silicon nitride. To a certain extent, the general picture mirrors the one found in Si-N systems, as expected from the similar valence structure of both elemental semiconductors. However, important differences appear in the deposition methods and alloy composition, the optical properties of as grown films, and the electrical behavior of nitrogen-doped amorphous layers. Structural studies are reviewed, including band structure calculations and the energies of nitrogen-related defects, which are compared with experimental data. Many important aspects of the electronic structure of Ge-N alloys are not yet completely understood and deserve a more careful investigation, in particular the structure of defects associated with N inclusion. The N doping of the a-Ge:H network appears to be very effective, the activation energy of the most effectively doped samples becoming around 120 meV. This is not the case with N-doped a-Si:H, the reasons for the difference remaining an open question. The lack of data on stoichiometric β-Ge3N4 prevents any reasonable assessment on the possible uses of the alloy in electronic and ceramic applications.

  19. Additive manufacturing.

    Science.gov (United States)

    Mumith, A; Thomas, M; Shah, Z; Coathup, M; Blunn, G

    2018-04-01

    Increasing innovation in rapid prototyping (RP) and additive manufacturing (AM), also known as 3D printing, is bringing about major changes in translational surgical research. This review describes the current position in the use of additive manufacturing in orthopaedic surgery. Cite this article: Bone Joint J 2018;100-B:455-60.

  20. The Effect Of Soil Moisture Content And Nitrogen And Phosphorous Addition On The Production Of CO2 And N2O In A Mature Red Spruce (Picea rubens Sarg.) Forest Soil

    Science.gov (United States)

    Kellman, L.; Diochon, A.

    2009-05-01

    Temperature, moisture and nutrient availability are key controls on the production of CO2 and N2O in the soil and all are altered when a system is perturbed by land management activities. Though the effect of temperature on production has been well characterized, the effects of moisture and nutrients on the production of CO2 and N2O are lesser known. This study examines the effects of soil moisture content and nutrient availability on the production of CO2 and N2O in the top 50 cm of mineral soil collected from a mature red spruce forest. To evaluate the effects of moisture and nutrients on the production of CO2 and N2O, we measured production of CO2 and N2O in an aerobic laboratory incubation conducted at 21 C. In a full factorial design, soils collected from four depth intervals (0-5, 5-20, 20-35, and 35- 50 cm) were adjusted to four water contents (30, 50, 75 and 100% water holding capacity) and amended with nitrogen, phosphorous or both. We compare the effects of the treatments on rates of production of CO2 and N2O to determine if the relative control of these factors on production differs with depth. The findings of this study suggest that the relative control of moisture and nutrient availability on production of CO2 and N2O differ within the soil profile, indicating the need for taking a multi-factor approach to understanding changes in greenhouse gas production from the soil in a managed system.

  1. Soils, County-wide soils cover - an aggregation of section-wide soil coverages with additional attributes. Primary attributes include mu symbol and ID, state symbol, name, category, percolation rate and passing percentage., Published in 2008, 1:1200 (1in=100ft) scale, Sedgwick County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Soils dataset current as of 2008. County-wide soils cover - an aggregation of section-wide soil coverages with additional attributes. Primary attributes include mu...

  2. Nitrogen-Doped Graphene for Photocatalytic Hydrogen Generation.

    Science.gov (United States)

    Chang, Dong Wook; Baek, Jong-Beom

    2016-04-20

    Photocatalytic hydrogen (H2 ) generation in a water splitting process has recently attracted tremendous interest because it allows the direct conversion of clean and unlimited solar energy into the ideal energy resource of H2 . For efficient photocatalytic H2 generation, the role of the photocatalyst is critical. With increasing demand for more efficient, sustainable, and cost-effective photocatalysts, various types of semiconductor photocatalysts have been intensively developed. In particular, on the basis of its superior catalytic and tunable electronic properties, nitrogen-doped graphene is a potential candidate for a high-performance photocatalyst. Nitrogen-doped graphene also offers additional advantages originating from its unique two-dimensional sp(2) -hybridized carbon network including a large specific surface area and exceptional charge transport properties. It has been reported that nitrogen-doped graphene can play diverse but positive functions including photo-induced charge acceptor/meditator, light absorber from UV to visible light, n-type semiconductor, and giant molecular photocatalyst. Herein, we summarize the recent progress and general aspects of nitrogen-doped graphene as a photocatalyst for photocatalytic H2 generation. In addition, challenges and future perspectives in this field are also discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. The nitrogen cycle on Mars

    Science.gov (United States)

    Mancinelli, Rocco L.

    1989-01-01

    Nirtogen is an essential element for the evolution of life, because it is found in a variety of biologically important molecules. Therefore, N is an important element to study from a exobiological perspective. In particular, fixed nitrogen is the biologically useful form of nitrogen. Fixed nitrogen is generally defines as NH3, NH4(+), NO(x), or N that is chemically bound to either inorganic or organic molecules, and releasable by hydrolysis to NH3 or NH4(+). On Earth, the vast majority of nitrogen exists as N2 in the atmosphere, and not in the fixes form. On early Mars the same situations probably existed. The partial pressure of N2 on early Mars was thought to be 18 mb, significantly less than that of Earth. Dinitrogen can be fixed abiotically by several mechanisms. These mechanisms include thernal shock from meteoritic infall and lightning, as well as the interaction of light and sand containing TiO2 which produces NH3 that would be rapidly destroyed by photolysis and reaction with OH radicals. These mechanisms could have been operative on primitive Mars.The chemical processes effecting these compounds and possible ways of fixing or burying N in the Martian environment are described. Data gathered in this laboratory suggest that the low abundance of nitrogen along (compared to primitive Earth) may not significantly deter the origin and early evolution of a nitrogen utilizing organisms. However, the conditions on current Mars with respect to nitrogen are quite different, and organisms may not be able to utilize all of the available nitrogen.

  4. Addition of proteic nitrogen during alcoholic fermentation for the production of cachaça Adição de nitrogênio protéico durante a fermentação alcoólica de caldo de cana para produção de cachaça

    Directory of Open Access Journals (Sweden)

    Elisangela Marques Jeronimo

    2008-04-01

    Full Text Available Cachaça is the denomination of a typical and exclusive Brazilian spirit produced from the distillation of fermented sugarcane juice must. The objective of this study was to evaluate the effect of adding yeast extract to the sugarcane juice used for sugarcane liquor production, because for the artisanal process no studies are available on nitrogen addition nor beverage quality, involving nitrogen complementation. Results of previous studies in the laboratory scale showed that sugarcane juice complementation with proteic nitrogen can be a beneficial practice for yeast multiplication and cellular growth, and also for the improvement of fermentation yield and liquor productivity. In this pilot scale study, using recycled yeast, the addition of proteic nitrogen influenced positively the cell viability, confirmed the yeast recycling operation, and also reduced the fermentation time. The proteic nitrogen addition did not affect the sensory acceptance of the distillate, and did not change the contents of volatile compounds, indicating that assimilable forms of proteic nitrogen can be helpfull to improve the alcoholic fermentation for cachaça production.Cachaça é a denominação de uma típica e exclusiva bebida destilada brasileira produzida a partir da destilação do caldo fermentado da cana-de-açúcar. O objetivo deste estudo foi avaliar a adição de extrato de levedura no mosto de caldo de cana para a produção de cachaça, pois em processo artesanal não há estudos específicos sobre as características fermentativas da levedura assim como sobre a qualidade da bebida, envolvendo a complementação nitrogenada e em específico a aplicação de nitrogênio protéico. Os resultados obtidos em trabalhos anteriores, conduzidos em laboratório, indicaram que nas destilarias artesanais de aguardente a complementação protéica do mosto pode constituir uma prática benéfica para a multiplicação e crescimento celular do fermento e conseq

  5. Nitrogen fixation apparatus

    Science.gov (United States)

    Chen, Hao-Lin

    1984-01-01

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O.sub.2 /cm promotes the formation of vibrationally excited N.sub.2. Atomic oxygen interacts with vibrationally excited N.sub.2 at a much quicker rate than unexcited N.sub.2, greatly improving the rate at which NO is formed.

  6. Occurrence and transport of nitrogen in the Big Sunflower River, northwestern Mississippi, October 2009-June 2011

    Science.gov (United States)

    Barlow, Jeannie R.B.; Coupe, Richard H.

    2014-01-01

    The Big Sunflower River Basin, located within the Yazoo River Basin, is subject to large annual inputs of nitrogen from agriculture, atmospheric deposition, and point sources. Understanding how nutrients are transported in, and downstream from, the Big Sunflower River is key to quantifying their eutrophying effects on the Gulf. Recent results from two Spatially Referenced Regressions on Watershed attributes (SPARROW models), which include the Big Sunflower River, indicate minimal losses of nitrogen in stream reaches typical of the main channels of major river systems. If SPARROW assumptions of relatively conservative transport of nitrogen are correct and surface-water losses through the bed of the Big Sunflower River are negligible, then options for managing nutrient loads to the Gulf of Mexico may be limited. Simply put, if every pound of nitrogen entering the Delta is eventually delivered to the Gulf, then the only effective nutrient management option in the Delta is to reduce inputs. If, on the other hand, it can be shown that processes within river channels of the Mississippi Delta act to reduce the mass of nitrogen in transport, other hydrologic approaches may be designed to further limit nitrogen transport. Direct validation of existing SPARROW models for the Delta is a first step in assessing the assumptions underlying those models. In order to characterize spatial and temporal variability of nitrogen in the Big Sunflower River Basin, water samples were collected at four U.S. Geological Survey gaging stations located on the Big Sunflower River between October 1, 2009, and June 30, 2011. Nitrogen concentrations were generally highest at each site during the spring of the 2010 water year and the fall and winter of the 2011 water year. Additionally, the dominant form of nitrogen varied between sites. For example, in samples collected from the most upstream site (Clarksdale), the concentration of organic nitrogen was generally higher than the concentrations of

  7. Dietary nitrogen and fish welfare.

    Science.gov (United States)

    Conceição, Luis E C; Aragão, Cláudia; Dias, Jorge; Costas, Benjamín; Terova, Genciana; Martins, Catarina; Tort, Lluis

    2012-02-01

    Little research has been done in optimizing the nitrogenous fraction of the fish diets in order to minimize welfare problems. The purpose of this review is to give an overview on how amino acid (AA) metabolism may be affected when fish are under stress and the possible effects on fish welfare when sub-optimal dietary nitrogen formulations are used to feed fish. In addition, it intends to evaluate the current possibilities, and future prospects, of using improved dietary nitrogen formulations to help fish coping with predictable stressful periods. Both metabolomic and genomic evidence show that stressful husbandry conditions affect AA metabolism in fish and may bring an increase in the requirement of indispensable AA. Supplementation in arginine and leucine, but also eventually in lysine, methionine, threonine and glutamine, may have an important role in enhancing the innate immune system. Tryptophan, as precursor for serotonin, modulates aggressive behaviour and feed intake in fish. Bioactive peptides may bring important advances in immunocompetence, disease control and other aspects of welfare of cultured fish. Fishmeal replacement may reduce immune competence, and the full nutritional potential of plant-protein ingredients is attained only after the removal or inactivation of some antinutritional factors. This review shows that AA metabolism is affected when fish are under stress, and this together with sub-optimal dietary nitrogen formulations may affect fish welfare. Furthermore, improved dietary nitrogen formulations may help fish coping with predictable stressful events.

  8. Broadening the ecological context of ungulate-ecosystem interactions: the importance of space, seasonality, and nitrogen.

    Science.gov (United States)

    Murray, Bryan D; Webster, Christopher R; Bump, Joseph K

    2013-06-01

    Spatial heterogeneity of soil resources, particularly nitrogen availability, affects herbaceous-layer cover and diversity in temperate forest ecosystems. Current hypotheses predict that ungulate herbivores influence nitrogen availability at the stand scale, but how ungulates affect nitrogen availability at finer spatial scales that are relevant to the herb layer is less understood. We tested the hypothesis that ungulate exclusion reduces the spatial complexity of nitrogen availability at neighborhood scales (1-26 m) apart from mean stand scale effects. This outcome was expected due to a lack of ungulate nitrogenous waste deposition within exclosures and seasonally variable ungulate habitat use. To test this hypothesis we examined spatial patterning of ammonium and nitrate availability, herb-layer cover and diversity, and under-canopy solar radiation using geostatistical models. Our study sites included six stands of eastern hemlock (Tsuga canadensis) forest: three where white-tailed deer (Odocoileus virginianus) were excluded and three that were accessible to deer. Where deer were present, patch sizes of ammonium availability, cover, and diversity were smaller compared to deer exclosures, whereas mean site-level effects were not significant. Within deer exclosures cover and solar radiation were more similar in patch size than were cover and nitrogen availability. Our results suggest that browsing ungulates affect spatial patterns of herb-layer cover and diversity through the excretion of nitrogenous wastes in small, discrete patches. Ungulate-excreted nitrogen deposition and herbivory were concentrated in the dormant season, allowing herb-layer plants a greater opportunity to benefit from nitrogen additions. Therefore, the impact of ungulates on nitrogen cycling in forest ecosystems varies with spatial scale and the seasonal timing of ungulate impacts. In this way, ungulates may function as a seasonally dependent link between fine-scale and landscape

  9. Phosphazene additives

    Science.gov (United States)

    Harrup, Mason K; Rollins, Harry W

    2013-11-26

    An additive comprising a phosphazene compound that has at least two reactive functional groups and at least one capping functional group bonded to phosphorus atoms of the phosphazene compound. One of the at least two reactive functional groups is configured to react with cellulose and the other of the at least two reactive functional groups is configured to react with a resin, such as an amine resin of a polycarboxylic acid resin. The at least one capping functional group is selected from the group consisting of a short chain ether group, an alkoxy group, or an aryloxy group. Also disclosed are an additive-resin admixture, a method of treating a wood product, and a wood product.

  10. Farmer driven national monitoring of nitrogen concentrations in drainage water in Denmark

    Science.gov (United States)

    Piil, Kristoffer; Lemming, Camilla; Kolind Hvid, Søren; Knudsen, Leif

    2014-05-01

    addition to demonstrating that nitrogen retention around the drain depth occurs under certain geological conditions. In order to make management plans for individual catchments areas, this new information must be taken into account. In addition, there is a need to improve on the data presented here by measuring drain flow in order to quantify total nitrogen loss from drains. Both drain flow measurements and methods to include the evident variability in drainage water nitrogen concentrations are under way in other projects within the framework of the DNmark research alliance.

  11. Understanding Nitrogen Fixation

    Energy Technology Data Exchange (ETDEWEB)

    Paul J. Chirik

    2012-05-25

    The purpose of our program is to explore fundamental chemistry relevant to the discovery of energy efficient methods for the conversion of atmospheric nitrogen (N{sub 2}) into more value-added nitrogen-containing organic molecules. Such transformations are key for domestic energy security and the reduction of fossil fuel dependencies. With DOE support, we have synthesized families of zirconium and hafnium dinitrogen complexes with elongated and activated N-N bonds that exhibit rich N{sub 2} functionalization chemistry. Having elucidated new methods for N-H bond formation from dihydrogen, C-H bonds and Broensted acids, we have since turned our attention to N-C bond construction. These reactions are particularly important for the synthesis of amines, heterocycles and hydrazines with a range of applications in the fine and commodity chemicals industries and as fuels. One recent highlight was the discovery of a new N{sub 2} cleavage reaction upon addition of carbon monoxide which resulted in the synthesis of an important fertilizer, oxamide, from the diatomics with the two strongest bonds in chemistry. Nitrogen-carbon bonds form the backbone of many important organic molecules, especially those used in the fertilizer and pharamaceutical industries. During the past year, we have continued our work in the synthesis of hydrazines of various substitution patterns, many of which are important precursors for heterocycles. In most instances, the direct functionalization of N{sub 2} offers a more efficient synthetic route than traditional organic methods. In addition, we have also discovered a unique CO-induced N{sub 2} bond cleavage reaction that simultaneously cleaves the N-N bond of the metal dinitrogen compound and assembles new C-C bond and two new N-C bonds. Treatment of the CO-functionalized core with weak Broensted acids liberated oxamide, H{sub 2}NC(O)C(O)NH{sub 2}, an important slow release fertilizer that is of interest to replace urea in many applications. The

  12. Effect of ensiling time and exogenous protease addition to whole-plant corn silage of various hybrids, maturities, and chop lengths on nitrogen fractions and ruminal in vitro starch digestibility.

    Science.gov (United States)

    Ferraretto, L F; Crump, P M; Shaver, R D

    2015-12-01

    The objective of this study was to evaluate the effects of ensiling time and exogenous protease addition on soluble CP (% of CP), ammonia-N (% of N), and ruminal in vitro starch digestibility (ivSD) of whole-plant corn silage (WPCS) from 3 hybrids, 2 maturities, and 2 chop lengths. Samples from 3 nonisogenic hybrids [brown midrib containing the bm3 gene mutation (BM3), dual-purpose (DP), or floury-leafy (LFY)] at 2 harvest maturities [2/3 kernel milk line (early) or 7d later (late)] with 2 theoretical lengths of cut settings (0.64 or 1.95cm) on a forage harvester were collected at harvest, treated with or without exogenous protease, and ensiled in triplicate in vacuum heat-sealed plastic bags for 0, 30, 60, 120, and 240d. Thus, the experiment consisted of 120 treatments (3 hybrids × 2 maturities × 2 chop lengths × 2 protease treatments × 5 time points) and 360 mini-silos (3 replications per treatment). Vitreousness, measured by dissection on unfermented kernels on the day of harvest, averaged 66.8, 65.0, and 59.0% for BM3, DP, and LFY, respectively. A protease × maturity interaction was observed with protease increasing ivSD in late but not early maturity. Ensiling time × hybrid interactions were observed for ammonia-N and soluble CP concentrations with greater values for FLY than other hybrids only after 120d of ensiling. Ensiling time × hybrid or protease × hybrid interactions were not observed for ivSD. Measurements of ivSD were greatest for FLY and lowest for BM3. Length of the ensiling period did not attenuate negative effects of kernel vitreousness or maturity on ivSD in WPCS. Results suggest that the dosage of exogenous protease addition used in the present study may reduce but not overcome the negative effects of maturity on ivSD in WPCS. No interactions between chop length and ensiling time or exogenous protease addition were observed for ivSD. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Nitrogen Compounds in Radiation Chemistry

    International Nuclear Information System (INIS)

    Sims, H.E.; Dey, G.R.; Vaudey, C.E.; Peaucelle, C.; Boucher, J.L.; Toulhoat, N.; Bererd, N.; Koppenol, W.H.; Janata, E.; Dauvois, V.; Durand, D.; Legand, S.; Roujou, J.L.; Doizi, D.; Dannoux, A.; Lamouroux, C.

    2009-01-01

    Water radiolysis in presence of N 2 is probably the topic the most controversy in the field of water radiolysis. It still exists a strong discrepancy between the different reports of ammonia formation by water radiolysis in presence of N 2 and moreover in absence of oxygen there is no agreement on the formation or not of nitrogen oxide like NO 2 - and NO 3 -. These discrepancies come from multiple sources: - the complexity of the reaction mechanisms where nitrogen is involved - the experimental difficulties - and, the irradiation conditions. The aim of the workshop is to capitalize the knowledge needed to go further in simulations and understanding the problems caused (or not) by the presence of nitrogen / water in the environment of radioactive materials. Implications are evident in terms of corrosion, understanding of biological systems and atmospheric chemistry under radiation. Topics covered include experimental and theoretical approaches, application and fundamental researches: - Nitrate and Ammonia in radiation chemistry in nuclear cycle; - NOx in biological systems and atmospheric chemistry; - Formation of Nitrogen compounds in Nuclear installations; - Nitrogen in future power plant projects (Gen4, ITER...) and large particle accelerators. This document gathers the transparencies available for 7 of the presentations given at this workshop. These are: - H.E SIMS: 'Radiation Chemistry of Nitrogen Compounds in Nuclear Power Plant'; - G.R. DEY: 'Nitrogen Compounds Formation in the Radiolysis of Aqueous Solutions'; - C.E. VAUDEY et al.: 'Radiolytic corrosion of nuclear graphite studied with the dedicated gas irradiation cell of IPNL'; - J.L. BOUCHER: 'Roles and biosynthesis of NO in eukaryotes and prokaryotes'; - W.H. KOPPENOL: 'Chemistry of NOx'; - E. JANATA: 'Yield of OH in N 2 O saturated aqueous solution'; - V. DAUVOIS: 'Analytical strategy for the study of radiolysis gases'

  14. Effect of water addition and nitrogen fertilization on the fluxes of CH4, CO2, NOx, and N2O following five years of elevated CO2 in the Colorado Shortgrass Steppe

    Directory of Open Access Journals (Sweden)

    A. R. Mosier

    2003-01-01

    Full Text Available An open-top-chamber (OTC CO2 enrichment (~720 mmol mol-1 study was conducted in the Colorado shortgrass steppe from April 1997 through October 2001. Aboveground plant biomass increased under elevated CO2 and soil moisture content was typically higher than under ambient CO2 conditions. Fluxes of CH4, CO2, NOx and N2O, measured weekly year round were not significantly altered by CO2 enrichment over the 55 month period of observation. During early summer of 2002, following the removal of the open-top-chambers from the CO2 enrichment sites in October 2001, we conducted a short term study to determine if soil microbial processes were altered in soils that had been exposed to double ambient CO2 concentrations during the growing season for the past five years. Microplots were established within each experimental site and 10 mm of water or 10 mm of water containing the equivalent of 10 g m-2 of ammonium nitrate-N was applied to the soil surface. Fluxes of CO2, CH4, NOx and N2O fluxes within control (unchambered, ambient CO2 and elevated CO2 OTC soils were measured at one to three day intervals for the next month. With water addition alone, CO2 and NO emission did not differ between ambient and elevated CO2 soils, while CH4 uptake rates were higher and N2O fluxes lower in elevated CO2 soils. Adding water and mineral N resulted in increased CO2 emissions, increased CH4 uptake and decreased NO emissions in elevated CO2 soils. The N addition study confirmed previous observations that soil respiration is enhanced under elevated CO2 and N immobilization is increased, thereby decreasing NO emission.

  15. Interaction of oxides of nitrogen and aromatic hydrocarbons under simulated atmospheric conditions

    International Nuclear Information System (INIS)

    Obrien, R.J.; Green, P.J.; Doty, R.A.; Vanderzanden, J.W.; Easton, R.R.; Irwin, R.P.

    1979-01-01

    The reactions of nitrogen oxides with aromatic hydrocarbons under simulated atmospheric conditions are investigated. Gaseous reaction products formed when toluene is irradiated under simulated atmospheric conditions in the presence of nitrogen oxides were analyzed by gas chromatography. Reaction products detected include acetylene, water, acetaldehyde, acetone, toluene, benzaldehyde, ortho-, meta- and para-cresol, benzyl nitrate and meta- and para-nitrotoluene. Reaction mechanisms yielding the various products are illustrated. The assumption that all the nitrogen oxides observed to be lost from the reaction products can be accounted for by nitric acid formation in the absence of ozone formation is verified by a model in which the hydroxyl radical is assumed to be the only means of removing toluene. Under conditions in which ozone is formed, nitrogen oxide loss is accounted for by ozone formation in addition to nitric acid formation

  16. Evaluation of the Impact of Alveolar Nitrogen Excretion on Indices Derived from Multiple Breath Nitrogen Washout

    Science.gov (United States)

    Nielsen, Niklas; Nielsen, Jorgen G.; Horsley, Alex R.

    2013-01-01

    Background A large body of evidence has now accumulated describing the advantages of multiple breath washout tests over conventional spirometry in cystic fibrosis (CF). Although the majority of studies have used exogenous sulphur hexafluoride (SF6) as the tracer gas this has also led to an increased interest in nitrogen washout tests, despite the differences between these methods. The impact of body nitrogen excreted across the alveoli has previously been ignored. Methods A two-compartment lung model was developed that included ventilation heterogeneity and dead space (DS) effects, but also incorporated experimental data on nitrogen excretion. The model was used to assess the impact of nitrogen excretion on washout progress and accuracy of functional residual capacity (FRC) and lung clearance index (LCI) measurements. Results Excreted nitrogen had a small effect on accuracy of FRC (1.8%) in the healthy adult model. The error in LCI calculated with true FRC was greater (6.3%), and excreted nitrogen contributed 21% of the total nitrogen concentration at the end of the washout. Increasing DS and ventilation heterogeneity both caused further increase in measurement error. LCI was increased by 6–13% in a CF child model, and excreted nitrogen increased the end of washout nitrogen concentration by 24–49%. Conclusions Excreted nitrogen appears to have complex but clinically significant effects on washout progress, particularly in the presence of abnormal gas mixing. This may explain much of the previously described differences in washout outcomes between SF6 and nitrogen. PMID:24039916

  17. Evaluation of the impact of alveolar nitrogen excretion on indices derived from multiple breath nitrogen washout.

    Directory of Open Access Journals (Sweden)

    Niklas Nielsen

    Full Text Available A large body of evidence has now accumulated describing the advantages of multiple breath washout tests over conventional spirometry in cystic fibrosis (CF. Although the majority of studies have used exogenous sulphur hexafluoride (SF6 as the tracer gas this has also led to an increased interest in nitrogen washout tests, despite the differences between these methods. The impact of body nitrogen excreted across the alveoli has previously been ignored.A two-compartment lung model was developed that included ventilation heterogeneity and dead space (DS effects, but also incorporated experimental data on nitrogen excretion. The model was used to assess the impact of nitrogen excretion on washout progress and accuracy of functional residual capacity (FRC and lung clearance index (LCI measurements.Excreted nitrogen had a small effect on accuracy of FRC (1.8% in the healthy adult model. The error in LCI calculated with true FRC was greater (6.3%, and excreted nitrogen contributed 21% of the total nitrogen concentration at the end of the washout. Increasing DS and ventilation heterogeneity both caused further increase in measurement error. LCI was increased by 6-13% in a CF child model, and excreted nitrogen increased the end of washout nitrogen concentration by 24-49%.Excreted nitrogen appears to have complex but clinically significant effects on washout progress, particularly in the presence of abnormal gas mixing. This may explain much of the previously described differences in washout outcomes between SF6 and nitrogen.

  18. Resposta do dendezeiro à adição de nitrogênio e sua influência na população de bactérias diazotróficas Response of African oil palm to nitrogen addition and its influence on the diazotrophic bacteria population

    Directory of Open Access Journals (Sweden)

    André Vieira de Carvalho

    2006-02-01

    Full Text Available O dendê (Elaeis guineensis, Jaquim pode produzir até sete toneladas de óleo por hectare por ano. O óleo vegetal é muito versátil e pode ser usado desde a indústria alimentícia até a produção de biocombustíveis. A planta é capaz de se associar com bactérias diazotróficas que colonizam raízes e caules. O objetivo deste trabalho foi avaliar a resposta à adubação nitrogenada de 17 genótipos de dendê no primeiro ano de cultivo e avaliar a influência da adição do N mineral sobre a população de bactérias diazotróficas, naturalmente presentes nas plântulas de dendezeiro. Foram utilizados potes de plástico completados com 50% de areia quartzoza e 50% de horizonte B de um Argissolo Vermelho-Amarelo, série Itaguaí, não esterilizado e extremamente pobre em nitrogênio. A uréia foi aplicada na dosagem de 33,68 kg ha-1 de N. Na presença do N, todos os genótipos melhoram os parâmetros biométricos, e houve aumento tanto do N total quanto do N acumulado. As populações de bactérias diazotróficas não foram influenciadas pela adição desse elemento. Dois genótipos foram selecionados, na presença e ausência de N, respectivamente, C-2001 e La Mé.African oil palm (Elaeis guineensis, Jaquim can produce up to 7 tons of oil per hectare per year. The vegetable oil is greatly versatile in its use, since food industry up to the production of fuels favorable to environmental protection. The plant has the potential to be associative with diazotrophic bacteria which colonize the roots and stem. The objective of this work was to evaluate 17 genotypes of E. guineensis in response to nitrogen addition and to verify the influence of this nitrogen on the diazotrophic population in an experiment using plastic pots filled with 50% quartz sand and 50% of non sterilized Horizon B; Red-Yellow Podzolic Soil series Itaguaí, extremely poor in nitrogen. Urea was used at a dose of 33.68 kg ha-1 de N. In the presence of the nitrogen, all

  19. Nitrogen Metabolite Repression of Metabolism and Virulence in the Human Fungal Pathogen Cryptococcus neoformans

    Science.gov (United States)

    Lee, I. Russel; Chow, Eve W. L.; Morrow, Carl A.; Djordjevic, Julianne T.; Fraser, James A.

    2011-01-01

    Proper regulation of metabolism is essential to maximizing fitness of organisms in their chosen environmental niche. Nitrogen metabolite repression is an example of a regulatory mechanism in fungi that enables preferential utilization of easily assimilated nitrogen sources, such as ammonium, to conserve resources. Here we provide genetic, transcriptional, and phenotypic evidence of nitrogen metabolite repression in the human pathogen Cryptococcus neoformans. In addition to loss of transcriptional activation of catabolic enzyme-encoding genes of the uric acid and proline assimilation pathways in the presence of ammonium, nitrogen metabolite repression also regulates the production of the virulence determinants capsule and melanin. Since GATA transcription factors are known to play a key role in nitrogen metabolite repression, bioinformatic analyses of the C. neoformans genome were undertaken and seven predicted GATA-type genes were identified. A screen of these deletion mutants revealed GAT1, encoding the only global transcription factor essential for utilization of a wide range of nitrogen sources, including uric acid, urea, and creatinine—three predominant nitrogen constituents found in the C. neoformans ecological niche. In addition to its evolutionarily conserved role in mediating nitrogen metabolite repression and controlling the expression of catabolic enzyme and permease-encoding genes, Gat1 also negatively regulates virulence traits, including infectious basidiospore production, melanin formation, and growth at high body temperature (39°–40°). Conversely, Gat1 positively regulates capsule production. A murine inhalation model of cryptococcosis revealed that the gat1Δ mutant is slightly more virulent than wild type, indicating that Gat1 plays a complex regulatory role during infection. PMID:21441208

  20. Nitrogen Catabolite Repression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Hofman-Bang, H Jacob Peider

    1999-01-01

    In Saccharomyces cerevisiae the expression of all known nitrogen catabolite pathways are regulated by four regulators known as Gln3, Gat1, Da180, and Deh1. This is known as nitrogen catabolite repression (NCR). They bind to motifs in the promoter region to the consensus sequence S' GATAA 3'. Gln3...... and Gat1 act positively on gene expression whereas :Da180 and Deh1 act negatively. Expression of nitrogen catabolite pathway genes known to be regulated by these four regulators are glutamine, glutamate, proline, urea, arginine, GABA, and allantoine. In addition, the expression of the genes encoding...... thereby providing a nitrogen source to the cell.In this review, all known promoter sequences related to expression of nitrogen catabolite pathways are discussed as well as other regulatory proteins. Overview of metabolic pathways and promoters are presented....

  1. Greenhouse gas emissions in salt marshes and their response to nitrogen loading

    Science.gov (United States)

    Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Carey, J.

    2015-12-01

    Salt marshes play an important role in global and regional carbon and nitrogen cycling. Anthropogenic nitrogen loading may alter greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient (between 1 and 10 gN m-2y-1) were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. We found that the studied salt marsh was a significant carbon sink (NEP ~ 380 gC m-2y-1). CH4 fluxes are 3 orders of magnitude less than CO2 fluxes in the salt marsh. Carbon fluxes are driven by light, salinity, tide, and temperature. We conclude that restoration or conservation of this carbon sink has a significant social benefit for carbon credit.

  2. Effects of nitrogen loading on greenhouse gas emissions in salt marshes

    Science.gov (United States)

    Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Mora, J.; Chen, X.; Carey, J.

    2014-12-01

    Salt marshes play an important role in global and regional carbon and nitrogen cycling. We tested the hypothesis that anthropogenic nitrogen loading alters greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate to triplicate plots bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. Our results will facilitate model development to simulate GHG emissions in coastal wetlands and support methodology development to assess carbon credits in preserving and restoring coastal wetlands.

  3. Development of commercial nitrogen-rich stainless steels

    International Nuclear Information System (INIS)

    Liljas, M.

    1999-01-01

    This paper reviews the development of nitrogen alloyed stainless steels. Nitrogen alloying of austenitic stainless steels started at an early stage and was to a large extent caused by nickel shortage. However, direct technical advantages such as increased strength of the nitrogen alloyed steels made them attractive alternatives to the current steels. It was not until the advent of the AOD (argon oxygen decarburisation) process in the late 1960s that nitrogen alloying could be controlled to such accuracy that it became successful commercially on a broader scale. The paper describes production aspects and how nitrogen addition influences microstructure and the resulting properties of austenitic and duplex stainless steels. For austenitic steels there are several reasons for nitrogen alloying. Apart from increasing strength nitrogen also improves structural stability, work hardening and corrosion resistance. For duplex steels nitrogen also has a decisive effect in controlling the microstructure during thermal cycles such as welding. (orig.)

  4. Spectroscopic study of nitrogen distribution in N-doped carbon nanotubes and nanofibers synthesized by catalytic ethylene-ammonia decomposition

    Science.gov (United States)

    Svintsitskiy, Dmitry A.; Kibis, Lidiya S.; Smirnov, Dmitry A.; Suboch, Arina N.; Stonkus, Olga A.; Podyacheva, Olga Yu.; Boronin, Andrei I.; Ismagilov, Zinfer R.

    2018-03-01

    Carbon and nitrogen species on the surface of carbon nanotubes (N-CNTs) and nanofibers (N-CNFs) were studied by X-ray absorption (XAS) and photoelectron spectroscopy (PES) including the analysis of nitrogen distribution over the depth of materials. The study was performed with a series of bamboo-like carbon nanotubes and nanofibers having the platelet-like and herringbone-like morphology. It was shown that the main nitrogen species in the composition of the studied materials are pyridine, pyrrole (and/or amino groups), graphite-like and oxidized states of nitrogen. In distinction to nanofibers, the bamboo-like nanotubes additionally contain molecular nitrogen encapsulated in the internal hollows. Spectral data for different depths of analysis were obtained by varying the energy of incident radiation. Such an approach revealed that N-CNTs are characterized by non-uniform distribution of chemically bound nitrogen species. Thus, nitrogen enrichment was observed on the external surface and in the internal arches of carbon nanotubes. Nitrogen enrichment in the subsurface region was found for N-CNFs, whereas the full depth analysis of N-distribution was limited by a large diameter of nanofibers.

  5. Aerobic Treatment of a Nitrogen-Limited Chemical Process Waste water.

    Science.gov (United States)

    P E, Daniel P Smith Ph D

    1996-06-01

    Nitrogen transformations and their effect on aerobic suspended growth treatment of an industrial wastewater were studied in three parallel bench-scale reactors operated at 5 "C at mean cell residence times (MCRT) of 15, 30, and 60 days. In normal process wastewater, the bulk of influent nitrogen was in organic form, and the fraction transformed was almost totally incorporated into synthesized biomass. Assimilative control by heterotrophs maintained ammonianitrogen levels below permitted effluent levels, and nitrification was not significant. Although volatile suspended solids had a nitrogen content of only 5% to 8%, effective organics removal was maintained, and total organic carbon and filtered daily average five-day biochemical oxygen demand (BODS) were below permitted effluent levels. A marked improvement in settleability and lower effluent total suspended solids was achieved by adding ammonia-nitrogen to the wastewater in excess of stoichiometric growth requirements. During a batch production cycle of a cationic chemical, the ratio of nitrogen to chemical oxygen demand and the fraction of the total influent nitrogen in soluble form increased in the wastewater. Reactor effluent ammonia levels increased to above permit levels at all three MCRTs during treatment of wastewater containing cationic production effluents. The magnitude of ammonia increase was greater for longer MCRTs, suggesting that synthesis of cell mass was not capable of assimilating the increased ammonia supply under these non-steady conditions. The experimental results suggest several potential strategies for operating the aerobic process at the treatment facility, including adding nitrogen to improve settleability and discontinuing these additions when wastewater contains a high ratio of nitrogen to chemical oxygen demand and an elevated soluble nitrogen fraction.

  6. Nitrogen Out of the Bottle: The Challenge of Managing the Genie

    Science.gov (United States)

    Galloway, J. N.

    2012-12-01

    Human activity converts more N2 to reactive nitrogen (Nr; all nitrogen species other than N2) than do natural terrestrial processes (mostly biological nitrogen fixation (BNF) in unmanaged ecosystems). Most of the Nr is created as a consequence of food production, fossil fuel combustion and industry. The Haber-Bosch process, invented in the early 20th century, now provides a virtually inexhaustible supply of nitrogen fertilizer. This one invention is responsible for the existence of about half of the world's population. That's the good news. The other news is that most of this nitrogen (and additional amounts from fossil fuel combustion and industry) is lost to the environment where it has exceeded the ability of the environment to convert it back to unreactive N2. The accumulating Nr contributes to smog, greenhouse effect, ecosystem eutrophication, acid rain and loss of stratospheric ozone in a sequential manner—the nitrogen cascade. Collectively these changes alter climate, decrease air quality, and diminish ecosystem sustainability. The challenge is how do we manage the genie—make sure we get the benefits of nitrogen, while minimizing the problems it causes. The paper will layout the possible, the probable and the improbable (but if it occurred, would be transformative) options for nitrogen management. Included will be the role that a nation vs. a person should play. The paper will also give examples of success stories, where nitrogen losses to the environment have been decreased, without impacting the service being provided—food and energy production. The paper will conclude with a forecast to the future, based upon the RCP scenarios for 2100.

  7. A bibliometric review of nitrogen research in eutrophic lakes and reservoirs.

    Science.gov (United States)

    Yao, Xiaolong; Zhang, Yunlin; Zhang, Lu; Zhou, Yongqiang

    2018-04-01

    The global application of nitrogen is far greater than phosphorus, and it is widely involved in the eutrophication of lakes and reservoirs. We used a bibliometric method to quantitatively and qualitatively evaluate nitrogen research in eutrophic lakes and reservoirs to reveal research developments, current research hotspots, and emerging trends in this area. A total of 2695 articles in the past 25years from the online database of the Scientific Citation Index Expended (SCI-Expanded) were analyzed. Articles in this area increased exponentially from 1991 to 2015. Although the USA was the most productive country over the past 25years, China achieved the top position in terms of yearly publications after 2010. The most active keywords related to nitrogen in the past 25years included phosphorus, nutrients, sediment, chlorophyll-a, carbon, phytoplankton, cyanobacteria, water quality, modeling, and stable isotopes, based on analysis within 5-year intervals from 1991 to 2015 as well as the entire past 25years. In addition, researchers have drawn increasing attention to denitrification, climate change, and internal loading. Future trends in this area should focus on: (1) nutrient amounts, ratios, and major nitrogen sources leading to eutrophication; (2) nitrogen transformation and the bioavailability of different nitrogen forms; (3) nitrogen budget, mass balance model, control, and management; (4) ecosystem responses to nitrogen enrichment and reduction, as well as the relationships between these responses; and (5) interactions between nitrogen and other stressors (e.g., light intensity, carbon, phosphorus, toxic contaminants, climate change, and hydrological variations) in terms of eutrophication. Copyright © 2017. Published by Elsevier B.V.

  8. Nitrogen biogeochemistry in the Caribbean sponge, Xestospongia muta: a source or sink of dissolved inorganic nitrogen?

    Directory of Open Access Journals (Sweden)

    Cara L Fiore

    Full Text Available BACKGROUND: Sponges have long been known to be ecologically important members of the benthic fauna on coral reefs. Recently, it has been shown that sponges are also important contributors to the nitrogen biogeochemistry of coral reefs. The studies that have been done show that most sponges are net sources of dissolved inorganic nitrogen (DIN; NH4 (+ and NO3 (- and that nitrification, mediated by their symbiotic prokaryotes, is the primary process involved in supplying DIN to adjacent reefs. METHODOLOGY/PRINCIPAL FINDINGS: A natural experiment was conducted with the Caribbean sponge Xestospongia muta from three different locations (Florida Keys, USA; Lee Stocking Island, Bahamas and Little Cayman, Cayman Islands. The DIN fluxes of sponges were studied using nutrient analysis, stable isotope ratios, and isotope tracer experiments. Results showed that the fluxes of DIN were variable between locations and that X. muta can be either a source or sink of DIN. Stable isotope values of sponge and symbiotic bacterial fractions indicate that the prokaryotic community is capable of taking up both NH4 (+ and NO3 (- while the differences in δ (15N between the sponge and bacterial fractions from the NH4 (+ tracer experiment suggest that there is translocation of labeled N from the symbiotic bacteria to the host. CONCLUSIONS/SIGNIFICANCE: Nitrogen cycling in X. muta appears to be more complex than previous studies have shown and our results suggest that anaerobic processes such as denitrification or anammox occur in these sponges in addition to aerobic nitrification. Furthermore, the metabolism of this sponge and its prokaryotic symbionts may have a significant impact on the nitrogen biogeochemistry on Caribbean coral reefs by releasing large amounts of DIN, including higher NH4 (+ concentrations that previously reported.

  9. Nitrogen biogeochemistry in the Caribbean sponge, Xestospongia muta: a source or sink of dissolved inorganic nitrogen?

    Science.gov (United States)

    Fiore, Cara L; Baker, David M; Lesser, Michael P

    2013-01-01

    Sponges have long been known to be ecologically important members of the benthic fauna on coral reefs. Recently, it has been shown that sponges are also important contributors to the nitrogen biogeochemistry of coral reefs. The studies that have been done show that most sponges are net sources of dissolved inorganic nitrogen (DIN; NH4 (+) and NO3 (-)) and that nitrification, mediated by their symbiotic prokaryotes, is the primary process involved in supplying DIN to adjacent reefs. A natural experiment was conducted with the Caribbean sponge Xestospongia muta from three different locations (Florida Keys, USA; Lee Stocking Island, Bahamas and Little Cayman, Cayman Islands). The DIN fluxes of sponges were studied using nutrient analysis, stable isotope ratios, and isotope tracer experiments. Results showed that the fluxes of DIN were variable between locations and that X. muta can be either a source or sink of DIN. Stable isotope values of sponge and symbiotic bacterial fractions indicate that the prokaryotic community is capable of taking up both NH4 (+) and NO3 (-) while the differences in δ (15)N between the sponge and bacterial fractions from the NH4 (+) tracer experiment suggest that there is translocation of labeled N from the symbiotic bacteria to the host. Nitrogen cycling in X. muta appears to be more complex than previous studies have shown and our results suggest that anaerobic processes such as denitrification or anammox occur in these sponges in addition to aerobic nitrification. Furthermore, the metabolism of this sponge and its prokaryotic symbionts may have a significant impact on the nitrogen biogeochemistry on Caribbean coral reefs by releasing large amounts of DIN, including higher NH4 (+) concentrations that previously reported.

  10. Albert Behnke: nitrogen narcosis.

    Science.gov (United States)

    Grover, Casey A; Grover, David H

    2014-02-01

    As early as 1826, divers diving to great depths noted that descent often resulted in a phenomenon of intoxication and euphoria. In 1935, Albert Behnke discovered nitrogen as the cause of this clinical syndrome, a condition now known as nitrogen narcosis. Nitrogen narcosis consists of the development of euphoria, a false sense of security, and impaired judgment upon underwater descent using compressed air below 3-4 atmospheres (99 to 132 feet). At greater depths, symptoms can progress to loss of consciousness. The syndrome remains relatively unchanged in modern diving when compressed air is used. Behnke's use of non-nitrogen-containing gas mixtures subsequent to his discovery during the 1939 rescue of the wrecked submarine USS Squalus pioneered the use of non-nitrogen-containing gas mixtures, which are used by modern divers when working at great depth to avoid the effects of nitrogen narcosis. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Nitrogenous air pollutants: Chemical and biological implications

    International Nuclear Information System (INIS)

    Grosjean, D.

    1979-01-01

    Theoretical and experimental studies on the health effects and chemistry of gaseous and particulate nitrogenous air pollutants are presented. Specific topics include Fourier transform infrared studies of nitrogenous compounds, the mechanism of peroxynitric acid formation, N-nitroso compounds in the air, the chemical transformations of nitrogen oxides during the sampling of combustion products, the atmospheric chemistry of peroxy nitrates, and the effects of nitrogen dioxide on lung metabolism. Attention is also given to the interaction of nitrogen oxides and aromatic hydrocarbons under simulated atmospheric conditions, the characterization of particulate amines, the role of ammonia in atmospheric aerosol chemistry, the relationship between sulfates and nitrates and tropospheric measurements of nitric acid vapor and particulate nitrates

  12. Marine nitrogen cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    of the marine nitrogen cycle and its influence on atmospheric CO 2 , in: The Ocean Carbon Cycle and Climate, edited by: Follows, M., and Oguz, T., Kluwer Academic, Dordrecht, 97-148, 2004. ISBN 1402020864. Citation Naqvi, Syed. 2006. "Marine nitrogen cycle...]. nitrogen_cycle> All text is available under the terms of the Creative Commons Attribution-Share Alike license. Please see the Encyclopedia of Earth's website for Terms of Use information. Supported...

  13. Developments in nitrogen generators

    International Nuclear Information System (INIS)

    Ayres, C.L.; Abrardo, J.M.; Himmelberger, L.M.

    1984-01-01

    Three process cycles for the production of nitrogen by the cryogenic separation of air are described in detail. These cycles are: (1) a waste expander cycle; (2) an air expander cycle; and (3) a cycle for producing large quantities of gaseous nitrogen. Each cycle has distinct advantages for various production ranges and delivery pressures. A dicussion of key parameters that must be considered when selecting a cycle to meet specific product requirements is presented. The importance of high plant reliability and a dependable liquid nitrogen back up system is also presented. Lastly, a discussion of plant safety dealing with the hazards of nitrogen, enriched oxygen, and hydrocarbons present in the air is reviewed

  14. Modeling Nitrogen Cycling in Delaware Estuary

    Science.gov (United States)

    Tabatabai, A.; Wilkin, J.

    2016-02-01

    Estuaries play a critical role in transforming the biogeochemical properties of water that originates from fluvial sources before it is ultimately discharged to the coastal ocean. Nutrient cycling and export within the Delaware Estuary affect the ecosystem functions both within Delaware Bay and on the adjacent continental shelf. A realistic coupled hydrodynamical-biogeochemical modeling framework was developed for the Delaware Bay using ROMS (Regional Ocean Modeling System; myroms.org) to quantify nitrogen fluxes and budgets. The modeling system includes inert and age tracers to identify water transport pathways. Model skill assessment used a host of in-situ physical and biogeochemical data, and satellite products. The nitrogen budget was estimated for a five-year period of 2007-2011. A large portion of the incoming nitrogen from terrestrial sources is denitrified or buried in the Bay. Positive net ecosystem production contributes to organic nitrogen export to the shelf. There is strong interannual variability in riverine nitrogen inflows, but in years with greater riverine nitrogen input most of the excess nitrogen is buried, denitrified or exported to the shelf; the net ecosystem production shows less variability. By taking advantage of a process-based biogeochemical model and an ensemble of available observed and empirical evidence, this study provides more detailed information about nitrogen fluxes in Delaware Estuary than previously established.

  15. Utilization of nitrogen fixing trees

    Energy Technology Data Exchange (ETDEWEB)

    Brewbaker, J.L.; Beldt, R. van den; MacDicken, K.; Budowski, G.; Kass, D.C.L.; Russo, R.O.; Escalante, G.; Herrera, R.; Aranguren, J.; Arkcoll, D.B.; Doebereinger, J. (cord.)

    1983-01-01

    Six papers from the symposium are noted. Brewbaker, J.L., Beldt, R. van den, MacDicken, K. Fuelwood uses and properties of nitrogen-fixing trees, pp 193-204, (Refs. 15). Includes a list of 35 nitrogen-fixing trees of high fuelwood value. Budowski, G.; Kass, D.C.L.; Russo, R.O. Leguminous trees for shade, pp 205-222, (Refs. 68). Escalante, G., Herrera, R., Aranguren, J.; Nitrogen fixation in shade trees (Erythrina poeppigiana) in cocoa plantations in northern Venezuela, pp 223-230, (Refs. 13). Arkcoll, D.B.; Some leguminous trees providing useful fruits in the North of Brazil, pp 235-239, (Refs. 13). This paper deals with Parkia platycephala, Pentaclethra macroloba, Swartzia sp., Cassia leiandra, Hymenaea courbaril, dipteryz odorata, Inga edulis, I. macrophylla, and I. cinnamonea. Baggio, A.J.; Possibilities of the use of Gliricidia sepium in agroforestry systems in Brazil, pp 241-243; (Refs. 15). Seiffert, N.F.; Biological nitrogen and protein production of Leucaena cultivars grown to supplement the nutrition of ruminants, pp 245-249, (Refs. 14). Leucaena leucocephala cv. Peru, L. campina grande (L. leucocephala), and L. cunningham (L. leucocephalae) were promising for use as browse by beef cattle in central Brazil.

  16. Nitrogen fixation in Red Sea seagrass meadows

    KAUST Repository

    Abdallah, Malak

    2017-05-01

    Seagrasses are key coastal ecosystems, providing many ecosystem services. Seagrasses increase biodiversity as they provide habitat for a large set of organisms. In addition, their structure provides hiding places to avoid predation. Seagrasses can grow in shallow marine coastal areas, but several factors regulate their growth and distribution. Seagrasses can uptake different kinds of organic and inorganic nutrients through their leaves and roots. Nitrogen and phosphorous are the most important nutrients for seagrass growth. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia by diazotrophic bacteria. This process provides a significant source of nitrogen for seagrass growth. The nitrogen fixation is controlled by the nif genes which are found in diazotrophs. The main goal of the project is to measure nitrogen fixation rates on seagrass sediments, in order to compare among various seagrass species from the Red Sea. Moreover, we will compare the fixing rates of the Vegetated areas with the bare sediments. This project will help to ascertain the role of nitrogen fixing bacteria in the development of seagrass meadows.

  17. Genetic basis of nitrogen use efficiency and yield stability across environments in winter rapeseed.

    Science.gov (United States)

    Bouchet, Anne-Sophie; Laperche, Anne; Bissuel-Belaygue, Christine; Baron, Cécile; Morice, Jérôme; Rousseau-Gueutin, Mathieu; Dheu, Jean-Eric; George, Pierre; Pinochet, Xavier; Foubert, Thomas; Maes, Olivier; Dugué, Damien; Guinot, Florent; Nesi, Nathalie

    2016-09-15

    Nitrogen use efficiency is an important breeding trait that can be modified to improve the sustainability of many crop species used in agriculture. Rapeseed is a major oil crop with low nitrogen use efficiency, making its production highly dependent on nitrogen input. This complex trait is suspected to be sensitive to genotype × environment interactions, especially genotype × nitrogen interactions. Therefore, phenotyping diverse rapeseed populations under a dense network of trials is a powerful approach to study nitrogen use efficiency in this crop. The present study aimed to determine the quantitative trait loci (QTL) associated with yield in winter oilseed rape and to assess the stability of these regions under contrasting nitrogen conditions for the purpose of increasing nitrogen use efficiency. Genome-wide association studies and linkage analyses were performed on two diversity sets and two doubled-haploid populations. These populations were densely genotyped, and yield-related traits were scored in a multi-environment design including seven French locations, six growing seasons (2009 to 2014) and two nitrogen nutrition levels (optimal versus limited). Very few genotype × nitrogen interactions were detected, and a large proportion of the QTL were stable across nitrogen nutrition conditions. In contrast, strong genotype × trial interactions in which most of the QTL were specific to a single trial were found. To obtain further insight into the QTL × environment interactions, genetic analyses of ecovalence were performed to identify the genomic regions contributing to the genotype × nitrogen and genotype × trial interactions. Fifty-one critical genomic regions contributing to the additive genetic control of yield-associated traits were identified, and the structural organization of these regions in the genome was investigated. Our results demonstrated that the effect of the trial was greater than the effect of nitrogen nutrition

  18. Soybean Nitrogen Fixing Attributes

    African Journals Online (AJOL)

    reproductive unit and nitrogen fixing attributes (Carruthers er. al., 2000). In combination with various lupin and forages, these authors showed that soybean grain yield was decreased by most treatments. In order to limit over population and pollution risks, low nitrogen fertilizer agricultural systems are likely to be advocated.

  19. Nitrogen use efficiency (NUE)

    NARCIS (Netherlands)

    Oenema, O.

    2015-01-01

    There is a need for communications about resource use efficiency and for measures to increase the use efficiency of nutrients in relation to food production. This holds especially for nitrogen. Nitrogen (N) is essential for life and a main nutrient element. It is needed in relatively large

  20. The Nitrogen Footprint Tool network: A multi-institution program to reduce nitrogen pollution

    Science.gov (United States)

    Castner, Elizabeth A.; Leah, Allison M.; Leary, Neal; Baron, Jill S.; Compton, Jana E.; Galloway, James N.; Hastings, Meredith G.; Kimiecik, Jacob; Lantz-Trissel, Jonathan; de la Riguera, Elizabeth; Ryals, Rebecca

    2017-01-01

    Anthropogenic sources of reactive nitrogen have local and global impacts on air and water quality and detrimental effects on human and ecosystem health. This paper uses the nitrogen footprint tool (NFT) to determine the amount of nitrogen (N) released as a result of institutional consumption. The sectors accounted for include food (consumption and upstream production), energy, transportation, fertilizer, research animals, and agricultural research. The NFT is then used for scenario analysis to manage and track reductions, which are driven by the consumption behaviors of both the institution itself and its constituent individuals. In this paper, the first seven completed institution nitrogen footprint results are presented. The institution NFT network aims to develop footprints for many institutions to encourage widespread upper-level management strategies that will create significant reductions in reactive nitrogen released to the environment. Energy use and food purchases are the two largest sectors contributing to institution nitrogen footprints. Ongoing efforts by institutions to reduce greenhouse gas emissions also help to reduce the nitrogen footprint, but the impact of food production on nitrogen pollution has not been directly addressed by the higher-ed sustainability community. The NFT Network found that institutions could reduce their nitrogen footprints by optimizing food purchasing to reduce consumption of animal products and minimize food waste, as well as reducing dependence on fossil fuels for energy.

  1. Reactions of nitrogen oxides with polymers

    Energy Technology Data Exchange (ETDEWEB)

    Pariiskii, Georgii B; Gaponova, I S; Davydov, Evgenii Ya [N.M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow (Russian Federation)

    2000-11-30

    The mechanisms of the reactions of nitrogen oxides and different classes of solid polymers are considered. Particular emphasis is given to the analysis of the mechanisms of the formation of stable nitroxyl radicals. Double bonds and amide groups of macromolecules, as well as hydroperoxides and peroxide macroradicals are shown to be involved in the reactions with nitrogen oxides. The application of nitrogen oxides for the preparation of spin-labelled polymers and the use of the ESR imaging technique (ESR tomography) for the investigation of the structure of the reaction front during nitration of solid polymers are considered. The bibliography includes 111 references.

  2. Chemistry of nitrogen oxide compounds

    International Nuclear Information System (INIS)

    Wells, A.

    1987-01-01

    The structure of nitrogen oxide compounds including: nitrates and nitrites, nitrosyl compounds of transition metals, rare earth, transition metal and actinide complexes, where nitrite- and nitrate ions are presented as ligands, is considered. Oxonitrate compounds, e.g. RbUO 2 (NO 3 ) 3 are also considered. The values of lengths and angles of bonds for some of these compounds are presented, volatility of Cd, Be and other metal nitrates are also discussed

  3. Ecology of the nitrogen cycle

    Energy Technology Data Exchange (ETDEWEB)

    Sprent, J.J.

    1987-01-01

    This book consists of two parts, approximately equal in size. The first part covers the general features of the nitrogen cycle, while the second part consists of case histories from particular environments. These include arid and semi-arid areas, tundras, peat soils, lakes, marshes, and such saline systems as salt marshes, coral reefs, intertidal zones, and the open sea. The last chapter discusses the human impact on the cycle through agriculture, forestry, and acidification.

  4. High nitrogen-dosed austenitic-stainless steels and duplex steels

    International Nuclear Information System (INIS)

    Harzenmoser, M.A.E.

    1990-01-01

    The austenitic grades represent the most important group in the family of stainless steels. Nitrogen addition to austenitic stainless steels provides much higher yield strength. It was the goal of the present work to develop new high strength austenitic and duplex stainless steels and to investigate the beneficial influence of nitrogen. More than 40 small ingots up to a weight of 1.5 kg were melted in a specially developed high pressure induction furnace. In addition 20 more alloys produced by a pressurized electro slag remelting facility were included in this investigation. The nitrogen content was varied between 0.37 and 1.47 wt.%. New coefficients are proposed for the nickel equivalent in the Schaeffler diagram; these are from 0.12 to 0.24 for manganese and 18 for nitrogen. The increase in yield strength by interstitially dissolved nitrogen is due to solid solution hardening and to increased grain boundary hardening. The addition of 1% nitrogen gives a yield strength of more than 759 MPa. The toughness remains very good. At room temperature nitrogen alloyed Fe-Cr-Mn austenitic steels give the highest product of strength and toughness. Nitrogen containing austenitic stainless steels show a substantial increase in strength at low temperature. From room temperature to 4K the yield strength is more than tripled. Nitrogen alloyed Fe-Cr-Mn austenitic stainless steels exhibit a ductile to brittle transition as the temperature is lowered. This is due to a planar deformation mode which could be caused by low stacking fault energy. Nickel improves the low temperature toughness and also raises the stacking fault energy. In the temperature range from 600 to 900 o C, Cr 2 N precipitate. The minimal time for precipitation is longer by a factor of 10 than in Fe-Cr-Ni grade. Nitrogen decreases the corrosion rate in austenitic and duplex stainless steels. The resistance to pitting corrosion can be described by the equation W L = %Cr + 3.3 %Mo + 30 %N. (author) figs., tabs., refs

  5. Nitrogen Cycling throughout Secondary Succession following Agricultural Disturbance in North-Central Virginia

    Science.gov (United States)

    Parisien, A.; Epstein, H. E.

    2017-12-01

    While much is known about the carbon cycle during succession that follows agricultural disturbance, less understood are the dynamics of the nitrogen cycle throughout secondary succession, and how plant-available nitrogen may or may not limit vegetation transitions and net primary productivity over time. Two chronosequences at the Blandy Experimental Farm in Boyce, north-central Virginia were examined to elucidate the complexities of the nitrogen cycle over a temporal successional gradient. Each chronosequence consists of one early, one mid, and one late secondary successional field ( 15 years, 30 years, and 100 years post agricultural abandonment, respectively). Five 10x10 m plots were established in each of the 6 fields for a total of 30 plots. Total soil nitrogen (and carbon) data were collected from soils to 30 cm depth at 10-cm intervals, and net nitrogen mineralization and nitrification were estimated using an in situ soil core with anion-cation exchange resin bag technique. Previous studies of carbon cycling at this location have indicated relatively constant soil CO2 efflux of approximately 1100 g C/m2, as well as increasing net primary production and therefore net ecosystem production, with time since abandonment. In addition, soil C and N, and the soil C:N ratio have been shown to increase from the early to late successional plots. Our current study marks the first comprehensive examination of soil nitrogen dynamics including mineralization and nitrification over a successional gradient at Blandy Farm. A thorough understanding of nitrogen dynamics during secondary succession is especially important in the southeastern United States, where a large portion of previously cultivated land has been abandoned over the past century, due to advances in farming efficiency and the move westward to more fertile soils. Much of the southeastern U.S. is now undergoing secondary succession, and quality data on the dynamics of nitrogen cycling during this procession can

  6. The marine nitrogen cycle: recent discoveries, uncertainties and the potential relevance of climate change

    NARCIS (Netherlands)

    Voss, M.; Bange, H.W.; Dippner, J.W.; Middelburg, J.J.; Montoya, J.P.; Ward, B.

    2013-01-01

    The ocean’s nitrogen cycle is driven by complex microbial transformations, including nitrogen fixation, assimilation, nitrification, anammox and denitrification. Dinitrogen is the most abundant form of nitrogen in sea water but only accessible by nitrogen-fixing microbes. Denitrification and

  7. Composting as a waste treatment technology: composting of sweet sorghum bagasse with different nitrogen sources

    International Nuclear Information System (INIS)

    Vicente, J.; Carrasco, J.E.; Negro, M.J.

    1996-01-01

    The purpose of this work is to study the aerobic solid fermentation of sweet sorghum bagasse in mixture with other additives as nitrogen sources to evaluate the utilization of this material as a substrate for composting. The characteristics of sweet sorghum bagasse, a material extremely low in nutrients as a consequence of sugar juice extraction but with a high organic carbon content, suggest that it may be possible to compost it with other organic wastes nitrogen rich, since this is an indispensable element for the protein synthesis of the microbial biomass which determines the fermentation process. Several additives, including different types of agricultural residues, residues from beer industries, industrial cellulases, an enzymatic commercial product for activation of composting, domestic sewage sludge as well as some inorganic sources, were used in the experiences. The additives were utilized in doses of 1,5 and 10% (in some case 0.1 and 1% by weight), and the final C/N ratio of the mixtures was adjusted to 30 with NH4NO3. taking to account the nitrogen content of the additives. The experiment was carried out in a constant chamber at 37degree centigree and lasted for two month. Best quality composts from a fertilizer perspective were obtained utilizing spillages and grain bagasse (beer industry residue) as a nitrogen sources. On the contrary the use of KNO3 as nitrogen source showed a relatively unfavourable effect on the composting. The results obtained show the suitability of sweet sorghum bagasse to be used as a carbon substrate for composting in mixtures with variety of nitrogen sources. (Author) 15 refs

  8. The nitrogen cycle.

    Science.gov (United States)

    Stein, Lisa Y; Klotz, Martin G

    2016-02-08

    Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth's atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and 'reactive nitrogen' (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides. Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions. Prior to the advent of the Haber-Bosch process (the industrial fixation of N2 into ammonia, NH3) in 1909, nearly all of the reactive nitrogen in the biosphere was generated and recycled by microorganisms. Although the Haber-Bosch process more than quadrupled the productivity of agricultural crops, chemical fertilizers and other anthropogenic sources of fixed nitrogen now far exceed natural contributions, leading to unprecedented environmental degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Cosmological evolution of the Nitrogen abundance

    Science.gov (United States)

    Vangioni, Elisabeth; Dvorkin, Irina; Olive, Keith A.; Dubois, Yohan; Molaro, Paolo; Petitjean, Patrick; Silk, Joe; Kimm, Taysun

    2018-03-01

    The abundance of nitrogen in the interstellar medium is a powerful probe of star formation processes over cosmological timescales. Since nitrogen can be produced both in massive and intermediate-mass stars with metallicity-dependent yields, its evolution is challenging to model, as evidenced by the differences between theoretical predictions and observations. In this work we attempt to identify the sources of these discrepancies using a cosmic evolution model. To further complicate matters, there is considerable dispersion in the abundances from observations of damped Lyα absorbers (DLAs) at z ˜ 2 - 3. We study the evolution of nitrogen with a detailed cosmic chemical evolution model and find good agreement with these observations, including the relative abundances of (N/O) and (N/Si). We find that the principal contribution of nitrogen comes from intermediate mass stars, with the exception of systems with the lowest N/H, where nitrogen production might possibly be dominated by massive stars. This last result could be strengthened if stellar rotation which is important at low metallicity can produce significant amounts of nitrogen. Moreover, these systems likely reside in host galaxies with stellar masses below 108.5M⊙. We also study the origin of the observed dispersion in nitrogen abundances using the cosmological hydrodynamical simulations Horizon-AGN. We conclude that this dispersion can originate from two effects: difference in the masses of the DLA host galaxies, and difference in the their position inside the galaxy.

  10. Nitrogen Deposition: A Component of Global Change Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Norby, Richard J.

    1997-12-31

    The global cycles of carbon and nitrogen are being perturbed by human activities that increase the transfer from large pools of nonreactive forms of the elements to reactive forms that are essential to the functioning of the terrestrial biosphere. The cycles are closely linked at all scales, and global change analyses must consider carbon and nitrogen cycles together. The increasing amount of nitrogen originating from fossil fuel combustion and deposited to terrestrial ecosystems as nitrogen oxides could increase the capacity of ecosystems to sequester carbon thereby removing some of the excess carbon dioxide from the atmosphere and slowing the development of greenhouse warming. Several global and ecosystem models have calculated the amount of carbon sequestration that can be attributed to nitrogen deposition based on assumptions about the allocation of nitrogen among ecosystem components with different carbon-nitrogen ratios. They support the premise that nitrogen deposition is responsible for a an increasing terrestrial carbon sink since industrialization began, but there are large uncertainties related to the continued capacity of ecosystems to retain exogenous nitrogen. Whether terrestrial ecosystems continue to sequester additional carbon will depend in part on their response to increasing atmospheric carbon dioxide concentrations, which is widely thought to be constrained by limited nitrogen availability. Ecosystem models generally support the conclusion that the responses of ecosystems to increasing concentrations of carbon dioxide will be larger, and the range of possible responses will be wider, in ecosystems with increased nitrogen inputs originating as atmospheric deposition.

  11. A seasonal nitrogen deposition budget for Rocky Mountain National Park.

    Science.gov (United States)

    Benedict, K B; Carrico, C M; Kreidenweis, S M; Schichtel, B; Malm, W C; Collett, J L

    2013-07-01

    Nitrogen deposition is a concern in many protected ecosystems around the world, yet few studies have quantified a complete reactive nitrogen deposition budget including all dry and wet, inorganic and organic compounds. Critical loads that identify the level at which nitrogen deposition negatively affects an ecosystem are often defined using incomplete reactive nitrogen budgets. Frequently only wet deposition of ammonium and nitrate are considered, despite the importance of other nitrogen deposition pathways. Recently, dry deposition pathways including particulate ammonium and nitrate and gas phase nitric acid have been added to nitrogen deposition budgets. However, other nitrogen deposition pathways, including dry deposition of ammonia and wet deposition of organic nitrogen, still are rarely included. In this study, a more complete seasonal nitrogen deposition budget was constructed based on observations during a year-long study period from November 2008 to November 2009 at a location on the east side of Rocky Mountain National Park (RMNP), Colorado, USA. Measurements included wet deposition of ammonium, nitrate, and organic nitrogen, PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 microm, nitrate, and ammonium) concentrations of ammonium, nitrate, and organic nitrogen, and atmospheric gas phase concentrations of ammonia, nitric acid, and NO2. Dry deposition fluxes were determined from measured ambient concentrations and modeled deposition velocities. Total reactive nitrogen deposition by all included pathways was found to be 3.65 kg N x ha(-1) yr(-1). Monthly deposition fluxes ranged from 0.06 to 0.54 kg N x ha(-1)yr(-1), with peak deposition in the month of July and the least deposition in December. Wet deposition of ammonium and nitrate were the two largest deposition pathways, together contributing 1.97 kg N x ha(-1)yr(-1) or 54% of the total nitrogen deposition budget for this region. The next two largest deposition pathways were wet

  12. Assessment of soil potential for microbial nitrogen cycling using quantitative PCR

    Science.gov (United States)

    Pereg, Lily; McMillan, Mary; Aldorri, Sind

    2016-04-01

    Nitrogen is an important nutrient for the synthesis of macromolecules, such as nucleic acids and proteins, in all organisms. Nitrogen cycling is essential for the production of different forms of nitrogenous molecules used by various organisms in the soil as available nitrogen sources. While nitrogen-fixing bacteria can utilize N2 as a nitrogen source, other microbes and plants need to assimilate N from fixed forms, e.g. ammonia or nitrate. Nitrogen cycling is largely derived by microbial activity in the soil. Examples include the reduction of N2 to ammonia by nitrogen fixation, production of nitrate by nitrification and the removal of available nitrogenous compounds by denitrification. We measured the potential of agricultural soils under various management practices to cycle nitrogen by measuring the abundance of functional genes involved in the nitrogen cycle. We report on the suitability of PCR-based methods as indicators of soil function potential.

  13. Integrated Science Assessment (ISA) for Oxides of Nitrogen ...

    Science.gov (United States)

    This draft ISA document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA’s decision on retaining or revising the current secondary standards for NO2, SO2, PM 2.5 and PM 10 since the prior release of the assessment. The intent of the ISA, according to the CAA, is to “accurately reflect the latest scientific knowledge expected from the presence of [a] pollutant in ambient air” (U.S. Code, 1970a, 1970b). It includes scientific research from atmospheric sciences, exposure and deposition, biogeochemistry, hydrology, soil science, marine science, plant physiology, animal physiology, and ecology conducted at multiple scales (e.g., population, community, ecosystem, landscape levels). Key information and judgments formerly found in the Air Quality Criteria Documents (AQCDs) for oxides of nitrogen, oxides of nitrogen and particulate matter for ecological effects are included; Appendixes provide additional details supporting the ISA. Together, the ISA and Appendixes serve to update and revise the last oxides of nitrogen and oxides of sulfur ISA which was published in 2008 and the ecological portion of the last particulate matter ISA, which was published in 2009.

  14. Pump apparatus including deconsolidator

    Energy Technology Data Exchange (ETDEWEB)

    Sonwane, Chandrashekhar; Saunders, Timothy; Fitzsimmons, Mark Andrew

    2014-10-07

    A pump apparatus includes a particulate pump that defines a passage that extends from an inlet to an outlet. A duct is in flow communication with the outlet. The duct includes a deconsolidator configured to fragment particle agglomerates received from the passage.

  15. Nitrogen enriched combustion of a natural gas internal combustion engine to reduce NO.sub.x emissions

    Science.gov (United States)

    Biruduganti, Munidhar S.; Gupta, Sreenath Borra; Sekar, R. Raj; McConnell, Steven S.

    2008-11-25

    A method and system for reducing nitrous oxide emissions from an internal combustion engine. An input gas stream of natural gas includes a nitrogen gas enrichment which reduces nitrous oxide emissions. In addition ignition timing for gas combustion is advanced to improve FCE while maintaining lower nitrous oxide emissions.

  16. Modeling nitrogen fluxes in Germany - where does the nitrogen go?

    Science.gov (United States)

    Klement, Laura; Bach, Martin; Breuer, Lutz

    2016-04-01

    According to the latest inventory of the EU Water Framework Directive, 26.3% of German groundwater bodies are in a poor chemical state regarding nitrate. Additionally, the EU initiated infringement proceedings against Germany for not meeting the quality standards of the EU Nitrate Directive. Agriculture has been determined as the main source of nitrate pollution due to over-fertilization and regionally high density of livestock farming. The nitrogen balance surplus is commonly used as an indicator characterizing the potential of nitrate leaching into groundwater bodies and thus also serves as a foundation to introduce legislative restrictions or to monitor the success of mitigation measures. Currently, there is an ongoing discussion which measures are suitable for reducing the risk of nitrate leaching and also to what extent. However, there is still uncertainty about just how much the nitrogen surplus has to be reduced to meet the groundwater quality standards nationwide. Therefore, the aims of our study were firstly to determine the level of the nitrogen surplus that would be acceptable at the utmost and secondly whether the currently discussed target value of 30 kg N per hectare agricultural land for the soil surface nitrogen balance would be sufficient. The models MONERIS (Modeling Nutrient Emissions in River System) and MoRE (Modelling of Regionalized Emissions), the latter based on the first, are commonly used for estimating nitrogen loads into the river system in Germany at the mesoscale, as well as the effect of mitigation measures in the context of the EU directive 2008/105/EC (Environmental quality standards applicable to surface water). We used MoRE to calculate nitrate concentration for 2759 analytical units in Germany. Main factors are the surplus of the soil surface nitrogen balance, the percolation rate and an exponent representing the denitrification in the vadose zone. The modeled groundwater nitrate concentrations did not correspond to the regional

  17. Optical modulator including grapene

    Science.gov (United States)

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang

    2016-06-07

    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  18. Commercial Nitrogen Fertilizer Purchased

    Data.gov (United States)

    U.S. Environmental Protection Agency — Amounts of fertilizer nitrogen (N) purchased by states in individual years 2003, 2005, 2007, 2009 and 2011, and the % change in average amounts purchased per year...

  19. Blood Urea Nitrogen Test

    Science.gov (United States)

    ... Culture Blood Gases Blood Ketones Blood Smear Blood Typing Blood Urea Nitrogen (BUN) BNP and NT-proBNP ... Luteinizing Hormone (LH) Lyme Disease Tests Magnesium Maternal Serum Screening, Second Trimester Measles and Mumps Tests Mercury ...

  20. Chronic nitrogen deposition influences the chemical dynamics ...

    Science.gov (United States)

    Atmospheric nitrogen deposition induces a forest carbon sink across broad parts of the Northern Hemisphere; this carbon sink may partly result from slower litter decomposition. Although microbial responses to experimental nitrogen deposition have been well-studied, evidence linking these microbial responses to changes in the degradation of specific compounds in decaying litter is sparse. We used wet chemistry and Fourier transform infrared spectroscopy (FTIR) methodologies to study the effects of chronic simulated nitrogen deposition on leaf litter and fine root chemistry during a three-year decomposition experiment at four northern hardwood forests in the north-central USA. Leaf litter and fine roots were highly different in initial chemistry such as concentrations of acid-insoluble fraction (AIF, or Klason lignin) and condensed tannins (CTs). These initial differences persisted over the course of decomposition. Results from gravimetrically-defined AIF and lignin/carbohydrate reference IR peak ratios both provide evidence that lignin in fine roots was selectively preserved under simulated nitrogen deposition. Lignin/carbohydrate peak ratios were strongly correlated with AIF, suggesting that AIF is a good predictor of lignin. Because AIF is abundant in fine roots, slower AIF degradation was the major driver of the slower fine root decomposition under nitrogen enrichment, explaining 73.9 % of the additional root mass retention. Nitrogen enrichment also slowed the

  1. Transgenic plants that exhibit enhanced nitrogen assimilation

    Science.gov (United States)

    Coruzzi, Gloria M.; Brears, Timothy

    1999-01-01

    The present invention relates to a method for producing plants with improved agronomic and nutritional traits. Such traits include enhanced nitrogen assimilatory and utilization capacities, faster and more vigorous growth, greater vegetative and reproductive yields, and enriched or altered nitrogen content in vegetative and reproductive parts. More particularly, the invention relates to the engineering of plants modified to have altered expression of key enzymes in the nitrogen assimilation and utilization pathways. In one embodiment of the present invention, the desired altered expression is accomplished by engineering the plant for ectopic overexpression of one of more the native or modified nitrogen assimilatory enzymes. The invention also has a number of other embodiments, all of which are disclosed herein.

  2. Brucella, nitrogen and virulence.

    Science.gov (United States)

    Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques

    2016-08-01

    The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

  3. Fertilizer nitrogen fixation in plants and its transmutation in soils in case of annual application

    International Nuclear Information System (INIS)

    Shilova, E.I.; Smirnov, P.M.; Khon, N.I.

    1974-01-01

    Using certain combinations of 15 N labeled and unlabeled nitrogen-containing fertilizers data were obtained for direct determination of nitrogen balance in the year of fertilization and subsequently. Annual and total (for 3 years) increment in utilization of soil nitrogen resulting from repeated fertilization was also determined. Coefficient of nitrogen utilization by barley decreased over the 3-year period after additional application of ammonium sulfate while biological immobilization of nitrogen tended to increase. Application of straw during the first year of the experiment did not significantly affect the nitrogen balance in the following years. The total coefficient of nitrogen utilization for the 2 to 3-year period was higher than that of the first year while biological immobilization was relatively lower. Additional utilization of soil nitrogen as compared to the control was the same over the whole 3-year period; additional mobilization (annual and total) was relatively higher due to lower removal of soil nitrogen in the subsequent years. Utilization of previously immobilized nitrogen was higher in the case of repeated fertilization than without application of nitrogen fertilizers. The content of newly immobilized nitrogen during 3 years in the hydrolyzable undistilable fraction (nitrogen of bounded amino acids) was relatively lower and this was accompanied by the growth of hydrolyzable distilable and unhydrolyzable nitrogen

  4. Exhaustive Conversion of Inorganic Nitrogen to Nitrogen Gas Based on a Photoelectro-Chlorine Cycle Reaction and a Highly Selective Nitrogen Gas Generation Cathode.

    Science.gov (United States)

    Zhang, Yan; Li, Jinhua; Bai, Jing; Shen, Zhaoxi; Li, Linsen; Xia, Ligang; Chen, Shuai; Zhou, Baoxue

    2018-02-06

    A novel method for the exhaustive conversion of inorganic nitrogen to nitrogen gas is proposed in this paper. The key properties of the system design included an exhaustive photoelectrochemical cycle reaction in the presence of Cl - , in which Cl· generated from oxidation of Cl - by photoholes selectively converted NH 4 + to nitrogen gas and some NO 3 - or NO 2 - . The NO 3 - or NO 2 - was finally reduced to nitrogen gas on a highly selective Pd-Cu-modified Ni foam (Pd-Cu/NF) cathode to achieve exhaustive conversion of inorganic nitrogen to nitrogen gas. The results indicated total nitrogen removal efficiencies of 30 mg L -1 inorganic nitrogen (NO 3 - , NH 4 + , NO 3 - /NH 4 + = 1:1 and NO 2 - /NO 3 - /NH 4 + = 1:1:1) in 90 min were 98.2%, 97.4%, 93.1%, and 98.4%, respectively, and the remaining nitrogen was completely removed by prolonging the reaction time. The rapid reduction of nitrate was ascribed to the capacitor characteristics of Pd-Cu/NF that promoted nitrate adsorption in the presence of an electric double layer, eliminating repulsion between the cathode and the anion. Nitrate was effectively removed with a rate constant of 0.050 min -1 , which was 33 times larger than that of Pt cathode. This system shows great potential for inorganic nitrogen treatment due to the high rate, low cost, and clean energy source.

  5. Background information on a multimedia nitrogen emission reduction strategy; Hintergrundpapier zu einer multimedialen Stickstoffemissionsminderungsstrategie

    Energy Technology Data Exchange (ETDEWEB)

    Geupel; Jering; Frey (and others)

    2009-04-15

    The background information report on a multimedia nitrogen reduction strategy covers the following chapters: 1. Introduction: the nitrogen cascade and the anthropogenic influence, environmental impact of increased nitrogen emissions and effects on human health. 2. Sources and balancing of anthropogenic nitrogen emissions in Germany. 3. Environmental quality targets, activity goals of environmental measures and instruments of an integrated nitrogen reduction strategy. 4. Conclusions and perspectives. The attachments include emission sources, nitrogen release and nitrogen transport in Germany; catalogue of measures and instruments according the criteria efficiency and cost-efficacy.

  6. Improving maize productivity through tillage and nitrogen management

    African Journals Online (AJOL)

    Continuous cultivation of fields with same implement (cultivator) creates a hard pan in the subsoil which adversely affects crop productivity. In addition to tillage, nitrogen management is a key factor for better crop growth and yield. Impact of different tillage systems and nitrogen management on yield attributes and grain yield ...

  7. Effect of irrigation disruption and biological nitrogen on growth and ...

    African Journals Online (AJOL)

    In addition, the maximum (4.29 %) harvest index was obtained from irrigation disruption at third and second harvest with 9 L/ha of nitroxin application. In conclusion, lower amounts of nitrogen was needed to produced the optimal yield of seed in water deficit situation compared with non stress condition, while the nitrogen ...

  8. Modelling the ecosystem effects of nitrogen deposition: Model of Ecosystem Retention and Loss of Inorganic Nitrogen (MERLIN

    Directory of Open Access Journals (Sweden)

    B. J. Cosby

    1997-01-01

    Full Text Available A catchment-scale mass-balance model of linked carbon and nitrogen cycling in ecosystems has been developed for simulating leaching losses of inorganic nitrogen. The model (MERLIN considers linked biotic and abiotic processes affecting the cycling and storage of nitrogen. The model is aggregated in space and time and contains compartments intended to be observable and/or interpretable at the plot or catchment scale. The structure of the model includes the inorganic soil, a plant compartment and two soil organic compartments. Fluxes in and out of the ecosystem and between compartments are regulated by atmospheric deposition, hydrological discharge, plant uptake, litter production, wood production, microbial immobilization, mineralization, nitrification, and denitrification. Nitrogen fluxes are controlled by carbon productivity, the C:N ratios of organic compartments and inorganic nitrogen in soil solution. Inputs required are: 1 temporal sequences of carbon fluxes and pools- 2 time series of hydrological discharge through the soils, 3 historical and current external sources of inorganic nitrogen; 4 current amounts of nitrogen in the plant and soil organic compartments; 5 constants specifying the nitrogen uptake and immobilization characteristics of the plant and soil organic compartments; and 6 soil characteristics such as depth, porosity, bulk density, and anion/cation exchange constants. Outputs include: 1 concentrations and fluxes of NO3 and NH4 in soil solution and runoff; 2 total nitrogen contents of the organic and inorganic compartments; 3 C:N ratios of the aggregated plant and soil organic compartments; and 4 rates of nitrogen uptake and immobilization and nitrogen mineralization. The behaviour of the model is assessed for a combination of land-use change and nitrogen deposition scenarios in a series of speculative simulations. The results of the simulations are in broad agreement with observed and hypothesized behaviour of nitrogen

  9. Atmospheric dry deposition of inorganic and organic nitrogen to the Bay of Bengal: Impact of continental outflow

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, B.; Sarin, M.M.; Sarma, V.V.S.S.

    focus of air-sea exchange studies (eg: SEAREX) on reactive nitrogen to the ocean surface had dealt with the deposition of soluble inorganic nitrogen. Some of these studies had also highlighted that all forms of soluble reactive nitrogen species... nitrogen (N Org ) in atmospheric aerosols. The soluble organic nitrogen in aerosols 3 comprises of different chemical species that include secondary organic nitrates, reduced amines or urea and terrestrial (land) derived organic nitrogen (Neff et al...

  10. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others.

    Science.gov (United States)

    Bandau, Franziska; Decker, Vicki Huizu Guo; Gundale, Michael J; Albrectsen, Benedicte Riber

    2015-01-01

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a

  11. Contribution of bacterial cell nitrogen to soil humic fractions

    International Nuclear Information System (INIS)

    Knowles, R.; Barro, L.

    1981-01-01

    Living cells of Serratia marcescens, uniformly labelled with 15 N, were added to samples of maple (Acer saccharum) and black spruce (Picea mariana) forest soils. After different periods of incubation from zero time to 100 days, the soils were subjected to alkali-acid and phenol extraction to provide humic acid, fulvic acid, humin and 'humoprotein' fractions. Significant amounts of the cell nitrogen were recovered in the humic and fulvic acids immediately after addition. After incubation, less cell nitrogen appeared in the humic acid and more in the fulvic acid. The amount of cell nitrogen recovered in the humin fraction increased with incubation. Roughly 5 to 10 per cent of the added cell nitrogen was found as amino acid nitrogen from humoprotein in a phenol extract of the humic acid. The data are consistent with the occurrence of co-precipitation of biologically labile biomass nitrogen compounds with humic polymers during the alkaline extraction procedure involved in the humic-fulvic fractionation. (orig.)

  12. Towards spatially differentiated regulation of nitrogen

    DEFF Research Database (Denmark)

    Lajer Højberg, Anker; Refsgaard, Jens Christian; Jørgensen, Lisbeth Flindt

    EU member states are challenged by nitrogen loads to estuaries and inland freshwater systems impeding the achievement of good ecological status as required by the Water Framework Directive (WFD). In Denmark nitrate leaching from the root zone has been reduced by 50% since 1987, but additional red...... advantage of local data and knowledge....

  13. THE EFFECTS OF INITIAL ABUNDANCES ON NITROGEN IN PROTOPLANETARY DISKS

    International Nuclear Information System (INIS)

    Schwarz, Kamber R.; Bergin, Edwin A.

    2014-01-01

    The dominant form of nitrogen provided to most solar system bodies is currently unknown, though available measurements show that the detected nitrogen in solar system rocks and ices is depleted with respect to solar abundances and the interstellar medium. We use a detailed chemical/physical model of the chemical evolution of a protoplanetary disk to explore the evolution and abundance of nitrogen-bearing molecules. Based on this model, we analyze how initial chemical abundances provided as either gas or ice during the early stages of disk formation influence which species become the dominant nitrogen bearers at later stages. We find that a disk with the majority of its initial nitrogen in either atomic or molecular nitrogen is later dominated by atomic and molecular nitrogen as well as NH 3 and HCN ices, where the dominant species varies with disk radius. When nitrogen is initially in gaseous ammonia, it later becomes trapped in ammonia ice except in the outer disk where atomic nitrogen dominates. For a disk with the initial nitrogen in the form of ammonia ice, the nitrogen remains trapped in the ice as NH 3 at later stages. The model in which most of the initial nitrogen is placed in atomic N best matches the ammonia abundances observed in comets. Furthermore, the initial state of nitrogen influences the abundance of N 2 H + , which has been detected in protoplanetary disks. Strong N 2 H + emission is found to be indicative of an N 2 abundance greater than n N 2 /n H 2 >10 −6 in addition to tracing the CO snow line. Our models also indicate that NO is potentially detectable, with lower N gas abundances leading to higher NO abundances

  14. Dialysis Pretreatment for Dissolved Organic Nitrogen Analysis in Freshwaters

    OpenAIRE

    Wang, Qiang; Hua, Bin; Yang, John; Liu, Fengjing; Zhu, Guocheng; Deng, Baolin

    2015-01-01

    Total dissolved nitrogen (TDN), including dissolved inorganic nitrogen (DIN) and dissolved organic nitrogen (DON), plays an important role in numerous environmental processes, such as nutrient cycling and lake and estuary eutrophication. The impact of DIN on environmental processes has been extensively studied. However, the understanding on DON in the environment is largely unknown, as there is no direct method for DON measurement. In practice, DON was determined by subtracting DIN from TDN. ...

  15. Water-bearing explosive containing nitrogen-base salt

    Energy Technology Data Exchange (ETDEWEB)

    Dunglinson, C.; Lyerly, W.M.

    1968-10-21

    A water-bearing explosive composition consists of an oxidizing salt component, a fuel component, and water. A sensitizer is included having an oxygen balance more positive than -150%, and consisting of a salt of an inorganic oxidizing acid and of an acyclic nitrogen base having no more than 2 hydrogen atoms bonded to the basic nitrogen and up to 3 carbons per basic nitrogen, and/or of a phenyl amine. 41 claims.

  16. A Systems Approach to Nitrogen Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Goins, Bobby [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2017-10-23

    A systems based approach will be used to evaluate the nitrogen delivery process. This approach involves principles found in Lean, Reliability, Systems Thinking, and Requirements. This unique combination of principles and thought process yields a very in depth look into the system to which it is applied. By applying a systems based approach to the nitrogen delivery process there should be improvements in cycle time, efficiency, and a reduction in the required number of personnel needed to sustain the delivery process. This will in turn reduce the amount of demurrage charges that the site incurs. In addition there should be less frustration associated with the delivery process.

  17. A Systems Approach to Nitrogen Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Goins, Bobby [Y-12 National Security Complex, Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)

    2017-10-17

    A systems based approach will be used to evaluate the nitrogen delivery process. This approach involves principles found in Lean, Reliability, Systems Thinking, and Requirements. This unique combination of principles and thought process yields a very in depth look into the system to which it is applied. By applying a systems based approach to the nitrogen delivery process there should be improvements in cycle time, efficiency, and a reduction in the required number of personnel needed to sustain the delivery process. This will in turn reduce the amount of demurrage charges that the site incurs. In addition there should be less frustration associated with the delivery process.

  18. Nitrogen fixation method and apparatus

    Science.gov (United States)

    Chen, H.L.

    1983-08-16

    A method and apparatus for achieving nitrogen fixation includes a volumetric electric discharge chamber. The volumetric discharge chamber provides an even distribution of an electron beam, and enables the chamber to be maintained at a controlled energy to pressure (E/p) ratio. An E/p ratio of from 5 to 15 kV/atm of O[sub 2]/cm promotes the formation of vibrationally excited N[sub 2]. Atomic oxygen interacts with vibrationally excited N[sub 2] at a much quicker rate than unexcited N[sub 2], greatly improving the rate at which NO is formed. 1 fig.

  19. Effects of agricultural nutrient management on nitrogen fate and transport in Lancaster County, Pennsylvania

    Science.gov (United States)

    Hall, D.W.; Risser, D.W.

    1993-01-01

    Nitrogen inputs to, and outputs from, a 55-acre site in Lancaster County, Pennsylvania, were estimated to determine the pathways and relative magnitude of loads of nitrogen entering and leaving the site, and to compare the loads of nitrogen before and after the implementation of nutrient management. Inputs of nitrogen to the site were manure fertilizer, commercial fertilizer, nitrogen in precipitation, and nitrogen in ground-water inflow; and these sources averaged 93, 4, 2, and 1 percent of average annual nitrogen additions, respectively. Outputs of nitrogen from the site were nitrogen in harvested crops, loads of nitrogen in surface runoff, volatilization of nitrogen, and loads of nitrogen in ground-water discharge, which averaged 37, less than 1,25, and 38 percent of average annual nitrogen removals from the site, respectively. Virtually all of the nitrogen leaving the site that was not removed in harvested crops or by volatilization was discharged in the ground water. Applications of manure and fertilizer nitrogen to 47.5 acres of cropped fields decreased about 33 percent, from an average of 22,700 pounds per year (480 pounds per acre per year) before nutrient management to 15,175 pounds of nitrogen per year (320 pounds per acre per year) after the implementation of nutrient management practices. Nitrogen loads in ground-water discharged from the site decreased about 30 percent, from an average of 292 pounds of nitrogen per million gallons of ground water before nutrient management to an average of 203 pounds of nitrogen per million gallons as a result of the decreased manure and commercial fertilizer applications. Reductions in manure and commercial fertilizer applications caused a reduction of approximately 11,000 pounds (3,760 pounds per year, 70 pounds per acre per year) in the load of nitrogen discharged in ground water from the 55-acre site during the three-year period 1987-1990.

  20. Exogenous nutrients and carbon resource change the responses of soil organic matter decomposition and nitrogen immobilization to nitrogen deposition.

    Science.gov (United States)

    He, Ping; Wan, Song-Ze; Fang, Xiang-Min; Wang, Fang-Chao; Chen, Fu-Sheng

    2016-03-29

    It is unclear whether exogenous nutrients and carbon (C) additions alter substrate immobilization to deposited nitrogen (N) during decomposition. In this study, we used laboratory microcosm experiments and (15)N isotope tracer techniques with five different treatments including N addition, N+non-N nutrients addition, N+C addition, N+non-N nutrients+C addition and control, to investigate the coupling effects of non-N nutrients, C addition and N deposition on forest floor decomposition in subtropical China. The results indicated that N deposition inhibited soil organic matter and litter decomposition by 66% and 38%, respectively. Soil immobilized (15)N following N addition was lowest among treatments. Litter (15)N immobilized following N addition was significantly higher and lower than that of combined treatments during the early and late decomposition stage, respectively. Both soil and litter extractable mineral N were lower in combined treatments than in N addition treatment. Since soil N immobilization and litter N release were respectively enhanced and inhibited with elevated non-N nutrient and C resources, it can be speculated that the N leaching due to N deposition decreases with increasing nutrient and C resources. This study should advance our understanding of how forests responds the elevated N deposition.

  1. Characterization and Oxidative Addition Reactions of Different ...

    African Journals Online (AJOL)

    1HNMRdata and density functional theory calculations illustrate that the coordination of the metal centre in [M(bpt-NH)(cod)] (M = Rh or Ir) occurs via the amine moiety and a nitrogen of a pyridine ring. Keywords: Rhodium(I), Iridium(I), Triazole, Cyclooctadiene, Oxidative Addition, Methyl Iodide, DFT. Attached PDF and ...

  2. [XPS and Raman spectral analysis of nitrogenated tetrahedral amorphous carbon (ta-C : N) films with different nitrogen content].

    Science.gov (United States)

    Chen, Wang-Shou; Zhu, Jia-Qi; Han, Jie-Cai; Tian, Gui; Tan, Man-Lin

    2009-01-01

    Nitrogenated tetrahedral amorphous carbon (ta-C : N) films were prepared on the polished C--Si substrates by introducing highly pure nitrogen gas into the cathode region and the depositing chamber synchronously using filtered cathodic vacuum arc (FCVA) technology. The nitrogen content in the films was controlled by changing the flow rate of nitrogen gas. The configuration of ta-C : N films was investigated by means of X-ray photoelectron spectroscopy (XPS) and visible Raman spectroscopy. It was shown that the nitrogen content in the films increased from 0.84 at% to 5.37 at% monotonously when the nitrogen flow rate was varied from 2 seem to 20 sccm. The peak position of C (1s) core level moved towards higher binding energy with the increase in nitrogen content. The shift of C (1s) peak position could be ascribed to the chemical bonding between carbon and nitrogen atoms even though more three-fold coordinated sp2 configuration as in graphite was formed when the films were doped with more nitrogen atoms. Additionally, the half width of C(1s) peak gradually was also broadened with increasing nitrogen content. In order to discover clearly the changing regularities of the microstructure of the films, the XPS C(1s) spectra and Raman spectra were deconvoluted using a Gaussian-Lorentzian mixed lineshape. It was shown that the tetrahedral hybridization component was still dominant even though the ratio of sp2/sp3 obtained from C(1s) spectra rose with the increase in nitrogen content. The Raman measurements demonstrated that the G peak position shifted towards higher frequency from 1,561 to 1,578 cm(-1) and the ratio of ID/IG also rose with the increase in nitrogen content. Both results indicated that the graphitizing tendency could occur with the increase in nitrogen content in the films.

  3. Nitrogen Oxide Emission, Economic Growth and Urbanization in China: a Spatial Econometric Analysis

    Science.gov (United States)

    Zhou, Zhimin; Zhou, Yanli; Ge, Xiangyu

    2018-01-01

    This research studies the nexus of nitrogen oxide emissions and economic development/urbanization. Under the environmental Kuznets curve (EKC) hypothesis, we apply the analysis technique of spatial panel data in the STIRPAT framework, and thus obtain the estimated impacts of income/urbanization on nitrogen oxide emission systematically. The empirical findings suggest that spatial dependence on nitrogen oxide emission distribution exist at provincial level, and the inverse N-shape EKC describes both income-nitrogen oxide and urbanization-nitrogen oxide nexuses. In addition, some well-directed policy advices are made to reduce the nitrogen oxide emission in future.

  4. Exploring the Fate of Nitrogen Heterocycles in Complex Prebiotic Mixtures

    Science.gov (United States)

    Smith, Karen E.; Callahan, Michael P.; Cleaves, Henderson J.; Dworkin, Jason P.; House, Christopher H.

    2011-01-01

    A long standing question in the field of prebiotic chemistry is the origin of the genetic macromolecules DNA and RNA. DNA and RNA have very complex structures with repeating subunits of nucleotides, which are composed of nucleobases (nitrogen heterocycles) connected to sugar-phosphate. Due to the instability of some nucleobases (e.g. cytosine), difficulty of synthesis and instability of D-ribose, and the likely scarcity of polyphosphates necessary for the modern nucleotides, alternative nucleotides have been proposed for constructing the first genetic material. Thus, we have begun to investigate the chemistry of nitrogen heterocycles in plausible, complex prebiotic mixtures in an effort to identify robust reactions and potential alternative nucleotides. We have taken a complex prebiotic mixture produced by a spark discharge acting on a gas mixture of N2, CO2, CH4, and H2, and reacted it with four nitrogen heterocycles: uracil, 5-hydroxymethyluracil, guanine, and isoxanthopterin (2-amino-4,7-dihydroxypteridine). The products of the reaction between the spark mixture and each nitrogen heterocycle were characterized by liquid chromatography coupled to UV spectroscopy and Orbitrap mass spectrometry. We found that the reaction between the spark mixtUl'e and isoxanthopterin formed one major product, which was a cyanide adduct. 5-hydroxymethyluracil also reacted with the spark mixture to form a cyanide adduct, uracil-5-acetonitrile, which has been synthesized previously by reacting HCN with S-hydroxymethyluracil. Unlike isoxanthopterin, the chromatogram of the 5-hydroxymethyluracil reaction was much more complex with multiple products including spark-modified dimers. Additionally, we observed that HMU readily self-polymerizes in solution to a variety of oligomers consistent with those suggested by Cleaves. Guanine and uracil, the biological nucleobases, did not react with the spark mixture, even at high temperature (100 C). This suggests that there are alternative

  5. Nitrogen Cycling In Latin America and : Drivers, Impacts And Vulnerabilities

    Science.gov (United States)

    Ometto, J. P.; Bustamante, M.; Forti, M. C.; Peres, T.; Stein, A. F.; Jaramillo, V.; Perez, C.; Pinho, P. F.; Ascarrunz, N.; Austin, A.; Martinelli, L. A.

    2015-12-01

    Latin America is at a crossroads where a balance should be found between production of the major agricultural commodities, reasonable and planned urbanization and conservation of its natural ecosystems and associated goods and services. Most of the natural biological fixation of the globe occurs in forests of Latin America. On the other hand, Latin America has one of the highest rate of deforestation in the world, and one of the highest increases in the use of nitrogen fertilizers. A better understanding of the responses of the N cycle to human impacts will allow better conservation of biodiversity and natural resources, with an improvement in food security and more effective land use choices in biofuel development. Latin America is a unique region in multiple aspects, and particularly relevant for this proposal are the broad climatic gradient and economic patterns that include a diverse range of natural ecosystems and socio-economic development pathways. Additionally, the region is impaired by the lack of information on actual impacts of human activity on N cycling across this diverse range of ecosystems. Finally, the large expanse of tropical ecosystems and reservoirs of biodiversity juxtaposed with an intense economic incentive for development make our understanding of human impacts in this context particularly important for global change research in the region. An evaluation of current and predicted changes in climate and land use on nitrogen stocks and fluxes in the region what is being develop by the Nnet network (Nitrogen Cycling In Latin America: Drivers, Impacts And Vulnerabilities ). This presentation will bring the latest results of this integrative initiative in Latin America, focusing on the nitrogen budget associated to provision of ecosystem services and climate change.

  6. Food, Feed and Fuel: a Story About Nitrogen

    Science.gov (United States)

    Galloway, J. N.; Burke, M. B.; Mooney, H. A.; Steinfeld, H.

    2008-12-01

    Humans obtain metabolic energy by eating food. Nitrogen is required to grow food, but natural supplies of N for human purposes have been inadequate since the beginning of the twentieth century. The Haber-Bosch process now provides a virtually inexhaustible supply of nitrogen, limited primarily by the cost of energy. However, most nitrogen used in food production is lost to the environment, where it cascades through environmental reservoirs contributing to many of the major environmental issues of the day. Furthermore, growing international trade in nitrogen-containing commodities is increasingly replacing wind and water as an important international transporter of nitrogen around the globe. Finally, the rapid growth in crop-based biofuels, and its attendant effects on the global production and trade of all agricultural commodities, could greatly affect global patterns of N use and loss. In the light of the findings above, this paper examines the role of nitrogen in food, feed and fuel production. It describes the beneficial consequences for food production and the negative consequences associated with the commodity nitrogen cascade and the environmental nitrogen cascade. The paper reviews estimates of future projections of nitrogen demands for food and fuel, including the impact of changing diets in the developing world. The paper concludes by presenting the potential interactions among global change, agricultural production and the nitrogen and carbon cycles.

  7. First principles investigation of nitrogenated holey graphene

    Science.gov (United States)

    Xu, Cui-Yan; Dong, Hai-Kuan; Shi, Li-Bin

    2018-04-01

    The zero band gap problem limits the application of graphene in the field of electronic devices. Opening the band gap of graphene has become a research issue. Nitrogenated holey graphene (NHG) has attracted much attention because of its semiconducting properties. However, the stacking orders and defect properties have not been investigated. In this letter, the structural and stacking properties of NHG are first investigated. We obtain the most stable stacking structure. Then, the band structures for bulk and multilayer NHG are studied. Impact of the strain on the band gaps and bond characteristics is discussed. In addition, we investigate formation mechanism of native defects of carbon vacancy (VC), carbon interstitial (Ci), nitrogen vacancy (VN), and nitrogen interstitial (Ni) in bulk NHG. Formation energies and transition levels of these native defects are assessed.

  8. Detection and Quantification of Nitrogen Compounds in Martian Solid Samples by the Sample Analysis at Mars (SAM) Instrument Suite

    Science.gov (United States)

    Stern, Jennifer C.; Navarro-Gonzalez, Rafael; Freissinet, Caroline; McKay, Christopher P.; Archer, Paul Douglas; Buch, Arnaud; Eigenbrode, Jennifer L.; Franz, Heather; Glavin, Daniel Patrick; Ming, Douglas W/; hide

    2013-01-01

    The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected both reduced and oxidized nitrogen-bearing compounds during the pyrolysis of surface materials from three sites at Gale Crater. Preliminary detections of nitrogen species include NO, HCN, ClCN, CH3CN, and TFMA (trifluoro-Nmethyl-acetamide). On Earth, nitrogen is a crucial bio-element, and nitrogen availability controls productivity in many environments. Nitrogen has also recently been detected in the form of CN in inclusions in the Martian meteorite Tissint, and isotopically heavy nitrogen (delta N-15 approx +100per mille) has been measured during stepped combustion experiments in several SNC meteorites. The detection of nitrogen-bearing compounds in Martian regolith would have important implications for the habitability of ancient Mars. However, confirmation of indigenous Martian nitrogen bearing compounds will require ruling out their formation from the terrestrial derivatization reagents (e.g. N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide, MTBSTFA and dimethylformamide, DMF) carried for SAM's wet chemistry experiment that contribute to the SAM background. The nitrogen species we detect in the SAM solid sample analyses can also be produced during laboratory pyrolysis experiments where these reagents are heated in the presence of perchlorate, a compound that has also been identified by SAM in Mars solid samples. However, this does not preclude a Martian origin for some of these compounds, which are present in nanomolar concentrations in SAM evolved gas analyses. Analysis of SAM data and laboratory breadboard tests are underway to determine whether nitrogen species are present at higher concentrations than can be accounted for by maximum estimates of nitrogen contribution from MTBSTFA and DMF. In addition, methods are currently being developed to use GC Column 6, (functionally similar to a commercial Q-Bond column), to separate and identify

  9. Microbial nitrogen cycling in Arctic snowpacks

    International Nuclear Information System (INIS)

    Larose, Catherine; Vogel, Timothy M; Dommergue, Aurélien

    2013-01-01

    Arctic snowpacks are often considered as chemical reactors for a variety of chemicals deposited through wet and dry events, but are overlooked as potential sites for microbial metabolism of reactive nitrogen species. The fate of deposited species is critical since warming leads to the transfer of contaminants to snowmelt-fed ecosystems. Here, we examined the role of microorganisms and the potential pathways involved in nitrogen cycling in the snow. Next generation sequencing data were used to follow functional gene abundances and a 16S rRNA (ribosomal ribonucleic acid) gene microarray was used to follow shifts in microbial community structure during a two-month spring-time field study at a high Arctic site, Svalbard, Norway (79° N). We showed that despite the low temperatures and limited water supply, microbial communities inhabiting the snow cover demonstrated dynamic shifts in their functional potential to follow several different pathways of the nitrogen cycle. In addition, microbial specific phylogenetic probes tracked different nitrogen species over time. For example, probes for Roseomonas tracked nitrate concentrations closely and probes for Caulobacter tracked ammonium concentrations after a delay of one week. Nitrogen cycling was also shown to be a dominant process at the base of the snowpack. (letter)

  10. Photosynthetic response to nitrogen source and different ratios of nitrogen and phosphorus in toxic cyanobacteria, Microcystis aeruginosa FACHB-905

    Directory of Open Access Journals (Sweden)

    Guotao Peng

    2016-06-01

    Full Text Available The frequent outbreak of cyanobacterial blooms has become a worldwide phenomenon in freshwater ecosystems. Studies have elucidated the close relationship between harmful algal blooms and nutrient contents, including the loading of nitrogen and the ratios of nitrogen (N and phosphorus (P. In this study, the effect of inorganic (nitrate and ammonium and organic (urea nitrogen at varied N/P ratios on the Microcystis aeruginosa FACHB-905 accumulation and photosynthesis was investigated.  The optimal NO3/P in this study were 30~50 indicated by the cell abundance (4.1×106/mL, pigment concentration (chlorophyll a 3.1 mg/L,  phycocyanin 8.3mg/L, and chlorophyll fluorescence parameters (rETR, Ek, α, φPSII and Fv/Fm values, while too high NO3-N (N/P=100:1 would cause an intracellular nitrate inhibition, leading to a decrease of photosynthetic activity. In addition, low concentration of NH4-N (N/P=4:1 would favor the M. aeruginosa growth and photosynthesis, and high NH4/P ratio (>16 would rise the ammonium toxicity of algal cells and affect the N assimilation. In urea treatments, M. aeruginosa responded similarly to the NH4-N treatments both in growth curves and pigment contents, and the favorable N/P ratio was between 16~30, suggested by the chlorophyll fluorescence parameters. The results demonstrated that the various chemical forms of N and N/P ratios have a significant impact on Microcystis abundance and photosynthesis. More work is needed to figure out the mechanism of nitrogen utilization by Microcystis and  the photosynthetic response to nutrient stress at the molecular level.

  11. Nitrogen availability for nitrogen fixing cyanobacteria upon growth ...

    African Journals Online (AJOL)

    The filamentous cyanobacterium Nostoc PCC 7120 is able to convert dinitrogen to ammonia in the absence of combined nitrogen. The expression of 20% of coding sequences from all major metabolic categories was examined in nitrogen fixing and non-nitrogen fixing growth conditions. The expression data were correlated ...

  12. Nitrogen Fixation in Cyanobacteria

    NARCIS (Netherlands)

    Stal, L.J.

    2008-01-01

    Cyanobacteria are oxygenic photosynthetic bacteria that are widespread in marine, freshwater and terrestrial environments and many of them are capable of fixing atmospheric nitrogen. But ironically, nitrogenase, the enzyme that is responsible for the reduction of N2, is extremely sensitive to O2.

  13. Phosphorus-nitrogen compounds

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 120; Issue 4. Phosphorus-nitrogen compounds: Part 15. Synthesis, anisochronism and the relationship between crystallographic and spectral data of monotopic spiro-crypta phosphazenes. Nuran Asmafi̇li̇z Eli̇f Ece İl Ter Zeynel Kiliç Tuncer Hökelek Ertan Şahin.

  14. Climate change affects key nitrogen-fixing bacterial populations on coral reefs

    NARCIS (Netherlands)

    Santos, Henrique F.; Carmo, Flavia L.; Duarte, Gustavo; Dini-Andreote, Francisco; Castro, Clovis B.; Rosado, Alexandre S.; van Elsas, Jan Dirk; Peixoto, Raquel S.

    2014-01-01

    Coral reefs are at serious risk due to events associated with global climate change. Elevated ocean temperatures have unpredictable consequences for the ocean's biogeochemical cycles. The nitrogen cycle is driven by complex microbial transformations, including nitrogen fixation. This study

  15. Rapid estimation of organic nitrogen in oil shale waste waters

    Energy Technology Data Exchange (ETDEWEB)

    Jones, B.M.; Daughton, C.G.; Harris, G.J.

    1984-04-01

    Many of the characteristics of oil shale process waste waters (e.g., malodors, color, and resistance to biotreatment) are imparted by numerous nitrogenous heterocycles and aromatic amines. For the frequent performance assessment of waste treatment processes designed to remove these nitrogenous organic compounds, a rapid and colligative measurement of organic nitrogen is essential. Quantification of organic nitrogen in biological and agricultural samples is usually accomplished using the time-consuming, wet-chemical Kjeldahl method. For oil shale waste waters, whose primary inorganic nitorgen constituent is amonia, organic Kjeldahl nitrogen (OKN) is determined by first eliminating the endogenous ammonia by distillation and then digesting the sample in boiling H/sub 2/SO/sub 4/. The organic material is oxidized, and most forms of organically bound nitrogen are released as ammonium ion. After the addition of base, the ammonia is separated from the digestate by distillation and quantified by acidimetric titrimetry or colorimetry. The major failings of this method are the loss of volatile species such as aliphatic amines (during predistillation) and the inability to completely recover nitrogen from many nitrogenous heterocycles (during digestion). Within the last decade, a new approach has been developed for the quantification of total nitrogen (TN). The sample is first combusted, a

  16. Nitrogen Limitation of Terrestrial Net Primary Production: Global Patterns From Field Studies with Nitrogen Fertilization

    Science.gov (United States)

    Lebauer, D. S.; Treseder, K. K.

    2006-12-01

    Net primary production (NPP) transfers carbon from the atmospheric CO2 pool into the biosphere. Experimental evidence demonstrates that NPP is often limited by nitrogen availability. Hence, accelerated nitrogen availability due to fertilizer production, fossil fuel use, and biomass burning could stimulate global NPP. Over the next century, these nitrogen sources are expected to both increase in strength and expand from their current concentration in the temperate regions of Europe and the United States into the tropical regions of South America, Southeast Asia, and India. In order to predict future carbon budgets, it is necessary to quantify the impact of nitrogen on NPP. Currently there is no synthesis of ecosystem scale experiments that evaluates responses among biomes and across environmental gradients. The aim of this investigation is to test the prediction that nitrogen limitation is widespread, and to evaluate global patterns of NPP response to nitrogen. The present study compiles results from field-based nitrogen addition experiments in a comprehensive meta-analysis. Published studies were obtained through key word searches and referenced articles. A response metric was derived from each study based on measurements of plant growth under ambient nitrogen deposition (control) and experimental nitrogen addition (treatment). This metric is the response ratio (R): the ratio of mean growth in treatment divided by control plots. Therefore, a positive effect of nitrogen results in R>1. A meta-analysis was performed on ln(R) weighted by within-study variance. We found that most ecosystems are nitrogen limited (P<0.0001) and that average growth response to nitrogen was 32%. However, response was not uniform across biomes. Significant responses were observed in grasslands and forests (P<0.0001), but not wetlands and tundra (P=0.08 and P=0.16). While mean annual precipitation (MAP) was significantly correlated to R overall (P<0.0001), the direction of the effect varied

  17. Efeito da adição do melaço na relação carbono/nitrogênio no cultivo de camarão Litopenaeus vannamei na fase berçário = Effect of molasses addition on carbon/nitrogen ratio in the nursery phase of Litopenaeus vannamei shrimp culture

    Directory of Open Access Journals (Sweden)

    Ugo Lima Silva

    2009-10-01

    Full Text Available Investigou-se o efeito da adição do melaço nas relações carbono:nitrogênio (C:N sobre o desempenho zootécnico do camarão Litopenaeus vannamei, na fase berçário, quando cultivado sem renovação de água. As relações do C:N foram avaliadas nas proporções de 25:1 (25M, 15:1 (15M e o controle (0M, sem aplicação de carbono, em delineamento experimental inteiramente casualizado, com quatro repetições. Pós-larvas (PL com peso inicial de 2,5 ± 0,5 mg, foram estocadas em 12 tanques (800 L volume útil, em densidades de 6,25 PL L-1, durante 42 dias de cultivo. Ao final do cultivo, os pesos finais dos camarões dos tratamentos 25M (532,0 mg e 15M (540,0 mg foram superiores (p The effect of molasses addiction on carbon:nitrogen ratios (C:N on the performance of Litopenaeus vannamei shrimp during the nursery phase cultured without water exchange was investigated. The C:N ratios were evaluated in 25:1 (25M and 15:1 (15M proportion and a control (0M, with no carbon source addition, in a randomized experimental design with four replicates. Post-larvae (PL with initial weight of 2.5 ± 0.5 mg were stocked in 12 tanks (800 L net volume, at the density of 6.25 PL L-1 during 42 culture days. At the end of culture, the shrimps weights on 25M (532.0 mg and 15M (540.0 mg treatments were higher (p < 0.05 than the 0M (428.6 mg treatment. Shrimp survival was high in all treatments (77.9 to 90.0%, but without significant difference (p ≥ 0.05. Therefore, the 15 and 25:1 C:N ratios showed an increased growth performance of nursery phase L. vannamei post-larvae cultured without water exchange.

  18. Ammonia Nitrogen Added to Diets Deficient in Dispensable Amino Acid Nitrogen Is Poorly Utilized for Urea Production in Growing Pigs.

    Science.gov (United States)

    Mansilla, Wilfredo D; Silva, Kayla E; Zhu, Cuilan L; Nyachoti, Charles M; Htoo, John K; Cant, John P; de Lange, Cornelis Fm

    2017-12-01

    Background: Including ammonia in low-crude protein (CP) diets deficient in dispensable amino acid (DAAs) increases nitrogen retention in growing pigs. Objective: We investigated the absorption and metabolism of dietary ammonia nitrogen in the portal-drained viscera (PDV) and liver of pigs fed a diet deficient in DAA nitrogen. Methods: Eight pigs with an initial mean ± SD body weight (BW) of 26.5 ± 1.4 kg were surgically fitted with 4 catheters each (portal, hepatic and mesenteric veins, and carotid artery). The pigs were fed (2.8 × 191 kcal/kg BW 0.60 ), for 7 d and every 8 h, a diet deficient in DAA nitrogen supplemented with increasing amounts of ammonia nitrogen (CP: 7.76%, 9.27%, and 10.77%; indispensable amino acid nitrogen:total nitrogen ratio: 0.71, 0.59, and 0.50 for control and low- and high-ammonia diets, respectively). The treatment sequence was based on a Latin square design with 3 consecutive periods. On the last day of each period, blood flows in the portal and hepatic veins were determined with a continuous infusion of ρ-amino hippuric acid into the mesenteric vein. Serial blood samples were taken to determine ammonia and urea nitrogen concentration. Net balances of ammonia and urea nitrogen were calculated for the PDV and liver. Results: Cumulative (8 h) ammonia nitrogen appearance in the portal vein increased ( P ≤ 0.05) with ammonia intake (433, 958, and 1629 ± 60 mg ammonia nitrogen/meal for control and low- and high-ammonia diets, respectively). The cumulative hepatic uptake of ammonia nitrogen increased ( P ≤ 0.05) with ammonia nitrogen supply. The cumulative urea nitrogen appearance in the hepatic vein tended to increase ( P ≤ 0.10) only in high-ammonia treatment (-92.5, -59.4, and 209.7 ± 92 mg urea nitrogen/meal for control and low- and high-ammonia diets, respectively) and, relative to the control diet, represented -6.0% and 11% of ammonia nitrogen intake. Conclusion: Dietary ammonia nitrogen is poorly utilized for urea

  19. The marine nitrogen cycle: recent discoveries, uncertainties and the potential relevance of climate change

    OpenAIRE

    Voss, Maren; Bange, Hermann W.; Dippner, Joachim W.; Middelburg, Jack J.; Montoya, Joseph P.; Ward, Bess

    2013-01-01

    The ocean's nitrogen cycle is driven by complex microbial transformations, including nitrogen fixation, assimilation, nitrification, anammox and denitrification. Dinitrogen is the most abundant form of nitrogen in sea water but only accessible by nitrogen-fixing microbes. Denitrification and nitrification are both regulated by oxygen concentrations and potentially produce nitrous oxide (N2O), a climate-relevant atmospheric trace gas. The world's oceans, including the coastal areas and upwelli...

  20. Cyanobacterial nitrogen fixation in the ocean: Diversity, regulation and ecology

    NARCIS (Netherlands)

    Stal, L.J.; Zehr, J.P.; Herrero, A.; Flores, E.

    2008-01-01

    Nitrogen is an essential and major component of biomass. While virtually all life depends on combined forms of nitrogen that are usually limited in availability, some prokaryotes, including many groups of cyanobacteria, can use the ubiquitous atmospheric dinitrogen (N2). As photoautotrophic bacteria

  1. Additive manufactured serialization

    Science.gov (United States)

    Bobbitt, III, John T.

    2017-04-18

    Methods for forming an identifying mark in a structure are described. The method is used in conjunction with an additive manufacturing method and includes the alteration of a process parameter during the manufacturing process. The method can form in a unique identifying mark within or on the surface of a structure that is virtually impossible to be replicated. Methods can provide a high level of confidence that the identifying mark will remain unaltered on the formed structure.

  2. Carbon and nitrogen stoichiometry across stream ecosystems

    Science.gov (United States)

    Wymore, A.; Kaushal, S.; McDowell, W. H.; Kortelainen, P.; Bernhardt, E. S.; Johnes, P.; Dodds, W. K.; Johnson, S.; Brookshire, J.; Spencer, R.; Rodriguez-Cardona, B.; Helton, A. M.; Barnes, R.; Argerich, A.; Haq, S.; Sullivan, P. L.; López-Lloreda, C.; Coble, A. A.; Daley, M.

    2017-12-01

    Anthropogenic activities are altering carbon and nitrogen concentrations in surface waters globally. The stoichiometry of carbon and nitrogen regulates important watershed biogeochemical cycles; however, controls on carbon and nitrogen ratios in aquatic environments are poorly understood. Here we use a multi-biome and global dataset (tropics to Arctic) of stream water chemistry to assess relationships between dissolved organic carbon (DOC) and nitrate, ammonium and dissolved organic nitrogen (DON), providing a new conceptual framework to consider interactions between DOC and the multiple forms of dissolved nitrogen. We found that across streams the total dissolved nitrogen (TDN) pool is comprised of very little ammonium and as DOC concentrations increase the TDN pool shifts from nitrate to DON dominated. This suggests that in high DOC systems, DON serves as the primary source of nitrogen. At the global scale, DOC and DON are positively correlated (r2 = 0.67) and the average C: N ratio of dissolved organic matter (molar ratio of DOC: DON) across our data set is approximately 31. At the biome and smaller regional scale the relationship between DOC and DON is highly variable (r2 = 0.07 - 0.56) with the strongest relationships found in streams draining the mixed temperate forests of the northeastern United States. DOC: DON relationships also display spatial and temporal variability including latitudinal and seasonal trends, and interactions with land-use. DOC: DON ratios correlated positively with gradients of energy versus nutrient limitation pointing to the ecological role (energy source versus nutrient source) that DON plays with stream ecosystems. Contrary to previous findings we found consistently weak relationships between DON and nitrate which may reflect DON's duality as an energy or nutrient source. Collectively these analyses demonstrate how gradients of DOC drive compositional changes in the TDN pool and reveal a high degree of variability in the C: N ratio

  3. Bacteria and the Nitrogen Economy.

    Science.gov (United States)

    Ayanaba, A.

    1982-01-01

    Biological nitrogen fixation accounts for almost 70 percent of nitrogen for plant growth. If food is to keep abreast of population growth, even more nitrogen must be fixed. For this international research institutes continue the search for natural variants in the bacterial population while also pursuing novel genetic engineering methods. (Author)

  4. Nitrogen Risk Assessment Model for Scotland: I. Nitrogen leaching

    Directory of Open Access Journals (Sweden)

    S. M. Dunn

    2004-01-01

    Full Text Available The Nitrogen Risk Assessment Model for Scotland (NIRAMS has been developed for prediction of streamwater N concentrations draining from agricultural land in Scotland. The objective of the model is to predict N concentrations for ungauged catchments, to fill gaps in monitoring data and to provide guidance in relation to policy development. The model uses nationally available data sets of land use, soils, topography and meteorology and has been developed within a Geographic Information System (GIS. The model includes modules to calculate N inputs to the land, residual N remaining at the end of the growing season, weekly time-series of leached N and transport of N at the catchment scale. This paper presents the methodology for calculating N balances for different land uses and for predicting the time sequence of N leaching after the end of the growing season. Maps are presented of calculated residual N and N leaching for the whole of Scotland and the spatial variability in N leaching is discussed. The results demonstrate the high variability in N leaching across Scotland. The simulations suggest that, in the areas with greatest residual N, the losses of N are not directly proportional to the amount of residual N, because of their coincidence with lower rainfall. In the companion paper, the hydrological controls on N transport within NIRAMS are described, and results of the full model testing are presented. Keywords: nitrogen, diffuse pollution, agriculture, leaching, land use, model, national, catchment

  5. Uncertainties in the fate of nitrogen: II. a quantitative assessment of the uncertainties in major nitrogen fluxes in the Netherlands

    NARCIS (Netherlands)

    Vries, de W.; Kros, J.; Oenema, O.; Klein, de J.J.M.

    2003-01-01

    Enhanced levels of nitrogen in the environment may have several adverse effects, including decreased plant species diversity in (semi) natural terrestrial ecosystems, eutrophication of surface waters, pollution of groundwater due to nitrate leaching and global warming due to nitrous and nitrogen

  6. Nitrogen Cycle Ninja, A Teaching Exercise.

    Science.gov (United States)

    Raun, William R.; And Others

    1997-01-01

    Assesses the effectiveness of using pop quizzes and rewards to improve student retention of the nitrogen cycle. Students able to diagram the N cycle on pop quizzes were rewarded with special cards that included the N cycle. These cards could then be used on subsequent tests in place of memory alone. Six of 11 students tested three months later…

  7. Economic incentives and alternative nitrogen regulation schemes

    DEFF Research Database (Denmark)

    Jensen, Jørgen Dejgård; Ørum, Jens Erik

    2014-01-01

    The objective of this chapter is to investigate economic incentives associated with changes in nitrogen regulation, including the distribution between farm types and geographically. The analysis is carried out on a partial equilibrium simulation model of the Danish agricultural sector—ESMERALDA. ...

  8. Process Design Manual for Nitrogen Control.

    Science.gov (United States)

    Parker, Denny S.; And Others

    This manual presents theoretical and process design criteria for the implementation of nitrogen control technology in municipal wastewater treatment facilities. Design concepts are emphasized through examination of data from full-scale and pilot installations. Design data are included on biological nitrification and denitrification, breakpoint…

  9. Nitrogen fate and Transport in Diverse Agricultural Watersheds

    Science.gov (United States)

    Essaid, H.; McCarthy, K. A.; Baker, N. T.

    2010-12-01

    Nitrogen mass budgets have been estimated for ten agricultural watersheds located in a range of hydrologic settings in order to understand the factors controlling the fate of nitrogen applied at the surface. The watersheds, study areas of the Agricultural Chemical Sources, Transport and Fate study of the U.S. Geological Survey National Water Quality Assessment Program, are located in Indiana (IN), Iowa (IA), Maryland (MD), Nebraska (NE), Mississippi (MS) and Washington (WA). They range in size from 7 to 1254 km2, with four of the watersheds nested within larger watersheds. Surface water outflow (normalized to watershed area) ranged from 4 to 83 cm/yr. Crops planted include corn, soybean, small grains, rice, cotton, orchards and vegetables. “Surplus nitrogen” was determined for each watershed by subtracting estimates of crop uptake and volatilization from estimates of nitrogen input from atmospheric deposition, plant fixation, and fertilizer and manure applications for the period from 1987 to 2004. This surplus nitrogen is transported though the watershed via surface and subsurface flow paths, while simultaneously undergoing transformations (such as denitrification and in-stream processing) that result in less export of nitrogen from the watershed. Surface-water discharge and concentration data were used to estimate the export of nitrogen from the watersheds (groundwater outflow from the watersheds was minimal). Subtracting nitrogen export from surplus nitrogen provides an estimate of the net amount of nitrogen removal occurring during internal watershed transport. Watershed average nitrogen surplus ranged from 6 to 49 kg-N/ha. The more permeable and/or greater water flux watersheds (MD, NE, and WA) tended to have larger surplus nitrogen, possibly due to less crop uptake caused by greater leaching and runoff of nitrogen. Almost all of the surplus nitrogen in the low permeability (MS) and tile drained watersheds (IA, IN) was exported from the watershed with

  10. Toward nitrogen neutral biofuel production.

    Science.gov (United States)

    Huo, Yi-Xin; Wernick, David G; Liao, James C

    2012-06-01

    Environmental concerns and an increasing global energy demand have spurred scientific research and political action to deliver large-scale production of liquid biofuels. Current biofuel processes and developing approaches have focused on closing the carbon cycle by biological fixation of atmospheric carbon dioxide and conversion of biomass to fuels. To date, these processes have relied on fertilizer produced by the energy-intensive Haber-Bosch process, and have not addressed the global nitrogen cycle and its environmental implications. Recent developments to convert protein to fuel and ammonia may begin to address these problems. In this scheme, recycling ammonia to either plant or algal feedstocks reduces the demand for synthetic fertilizer supplementation. Further development of this technology will realize its advantages of high carbon fixation rates, inexpensive and simple feedstock processing, in addition to reduced fertilizer requirements. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Nitrogen fixation in Asaia sp. (family Acetobacteraceae).

    Science.gov (United States)

    Samaddar, Neeloy; Paul, Arundhati; Chakravorty, Somnath; Chakraborty, Writachit; Mukherjee, Joydeep; Chowdhuri, Debarati; Gachhui, Ratan

    2011-08-01

    The genus Asaia (family Acetobacteraceae) was first introduced with a single species-Asaia bogorensis and later six more species were described namely A. siamensis, A. krungthepensis, A. lannaensis, A. platycodi, A. prunellae, and A. astilbes. Acetobacteraceae family has been divided into ten genera but, only three of them include nitrogen fixing species: Gluconacetobacter, Acetobacter, and Swaminathania. This article originated from our study primarily aimed to isolate new endosymbiotic nitrogen fixer among Acetobacteraceae during which we have isolated, for the first time in India, four different strains of Asaia sp. from three different sources: Michalia champaca flower, Anopheles mosquito, and ant Tetraponera rufonigra. All the endosymbiotic strains isolated possess the ability to fix nitrogen. Evidence for both nitrogenase activity and the presence of nifH gene in isolated Asaia sp. is presented. Asaia bogorensis (MTCC 4041(T)) and A. siamensis (MTCC 4042(T)), two of the validated type strains available from the repository, were tested positive for the presence of functional nitrogenase. The nifH gene sequences from these type strains were also confirmed and compared with other nitrogen fixing members of the family Acetobacteraceae. Our result corroborate with the previous reports that Asaia sp. are indeed widely distributed in nature but this is the first time demonstration of their functional nitrogenase activity. This study shows Asaia sp. as fourth genera of nitrogen fixing bacteria in the family Acetobacteraceae.

  12. Climate change impacts of US reactive nitrogen.

    Science.gov (United States)

    Pinder, Robert W; Davidson, Eric A; Goodale, Christine L; Greaver, Tara L; Herrick, Jeffrey D; Liu, Lingli

    2012-05-15

    Fossil fuel combustion and fertilizer application in the United States have substantially altered the nitrogen cycle, with serious effects on climate change. The climate effects can be short-lived, by impacting the chemistry of the atmosphere, or long-lived, by altering ecosystem greenhouse gas fluxes. Here we develop a coherent framework for assessing the climate change impacts of US reactive nitrogen emissions, including oxides of nitrogen, ammonia, and nitrous oxide (N(2)O). We use the global temperature potential (GTP), calculated at 20 and 100 y, in units of CO(2) equivalents (CO(2)e), as a common metric. The largest cooling effects are due to combustion sources of oxides of nitrogen altering tropospheric ozone and methane concentrations and enhancing carbon sequestration in forests. The combined cooling effects are estimated at -290 to -510 Tg CO(2)e on a GTP(20) basis. However, these effects are largely short-lived. On a GTP(100) basis, combustion contributes just -16 to -95 Tg CO(2)e. Agriculture contributes to warming on both the 20-y and 100-y timescales, primarily through N(2)O emissions from soils. Under current conditions, these warming and cooling effects partially offset each other. However, recent trends show decreasing emissions from combustion sources. To prevent warming from US reactive nitrogen, reductions in agricultural N(2)O emissions are needed. Substantial progress toward this goal is possible using current technology. Without such actions, even greater CO(2) emission reductions will be required to avoid dangerous climate change.

  13. Effects from additives on deacetylation of chitin

    International Nuclear Information System (INIS)

    Campana Filho, Sergio P.; Signini, Roberta

    2001-01-01

    Deacetylation reactions of commercial chitin were carried out in aqueous sodium hydroxide solution at 115 deg C for 6 hours. The effect from additives (sodium borohydride or anthraquinone) and of bubbling inert gas (nitrogen or argon) on the characteristics of deacetylated samples were evaluated. Average degrees of acetylation and intrinsic viscosity were determined by 1 H NMR spectroscopy and capillary viscometry, respectively. X-ray diffraction was employed to evaluate changes in crystallinity and infrared spectroscopy was used to monitor structural changes due to deacetylation. The bubbling of inert gas during the deacetylation reaction resulted in more crystalline samples of chitosan. Deacetylation carried out without any additive produced slightly more deacetylated chitosan but they were severely depolymerized. The depolymerization process was much less important when sodium borohydride was added to the reaction medium but the addition of anthraquinone and the bubbling of nitrogen, or argon, did not have any effect, this suggests that oxygen is not required for depolymerization. (author)

  14. An Hybrid liquid nitrogen system to cool a large detector

    Science.gov (United States)

    l'Allemand, J. L. Lizon a.

    2017-12-01

    OmegaCAM is a wide field camera housing a mosaic of 32 CCD detectors. For the optimal trade-off between dark current, sensitivity, and cosmetics, these detectors need to be operated at a temperature of about 155 K. The detectors mosaic with a total area of 630 cm2 directly facing the Dewar entrance window, is exposed to a considerable radiation heat load. This can only be achieved with a high-performing cooling system. In addition this system has to be operated at the moving focal plane of a telescope. The paper describes the cooling system, which is build such that it makes the most efficient use of the cooling power of the liquid nitrogen. This is obtained by forcing the nitrogen through a series of well designed and strategically distributed heat exchangers. Results and performance of the system recorded during the laboratory system testing are reported as well. In addition to the cryogenic performance, the document reports also about the overall performance of the instrument including long term vacuum behavior.

  15. The fertilizer nitrogen problem

    International Nuclear Information System (INIS)

    Olson, R.A.; Halstead, E.H.

    1974-01-01

    A world-wide fossil fuel crisis has surfaced in the past year by reason of shortage and high cost, which is felt throughout all segments of human society. Nor has the agriculture sector, with its very high demand for energy to supply its power, machinery, fertilizer, processing and transport, escaped the energy crisis. Among the agricultural inputs, fertilizer nitrogen is one of major concern. This commodity is currently in extremely short supply, world prices having more than doubled in the past year alone. Serious as this situation is to agricultural production in the highly developed countries of the world, it is a real disaster to the production potential of the developing countries. The birth of the 'Green Revolution' in those countries in the last ten years came about from an amalgamation of higher yielding varieties, improved pest and disease control, better crop watering practices, and the introduction of fertilizer nitrogen. Shortcomings in any one of these requisites invalidates the entire package. (author)

  16. Phosphate glasses, containing nitrogen

    International Nuclear Information System (INIS)

    Lisitsyna, E.A.; Khalilev, V.D.; Koryavin, A.A.; Goncharova, L.N.

    1987-01-01

    Possibilities of nitrogen-containing glass synthesis by the introduction into the charge of ammonium salts, as well as aluminium nitride, are studied. Zinc alumoyttrium phosphate glass (mol. %) Zn(PO 3 ) 2 - 4O, Al(PO 3 ) 3 - 3O, Y(PO 3 ) 3 -3O is suggested as a matrix. It is shown that the effect of amide and imide groups on the properties of the glass is less noticeable than the effect of nitride groups. Direct introduction of nitride constituent was realized using AlN, but aluminium introduction was taken into account so that the oxide was subtracted. The attempt to introduce more than 2.5 mass % of nitrogen into initial matrix by aluminium nitride has failed due to repeated restoration of glass with amorphous phosphorus isolation

  17. Nitrogen Research Programme STOP

    International Nuclear Information System (INIS)

    Erisman, J.W.; Van der Eerden, L.

    2000-01-01

    Nitrogen pollution is one of the main threats to the environment now in the Netherlands as well as other parts of Europe. In order to address the main gaps on the issues of nitrogen pollution related to the local scale, the Ministries of Housing, Physical Planning and Environment (VROM) and of Agriculture, Nature Management and Fisheries (LNV) have initiated a research programme, the Dutch Nitrogen Research Programme (STOP), which aims to provide a scientific basis to develop and implement policy on a local scale for the realisation and conservation of the EHS ('Dutch Mainframe of Natural Landscapes'). The results of the programme show that the description of emissions from manure in the field is difficult to describe and show large uncertainties. On the contrary, emissions from housings could be modelled well, if local actual data were available. The OPS model to describe the dispersion and deposition was evaluated with the measurements and the limitations were quantified. It appears that the model works well on the long term, whereas on the short term (hours) and short distance (tenths of meters) there is large uncertainty, especially in complex terrain. Critical loads for nitrogen for ecosystems were evaluated. Furthermore, the effect of management options was quantified. A method to determine critical loads as a function of soil conditions, such as acidification and water availability was derived. This resulted in a combination of the soil model SMART and the so-called 'nature planner' (Natuurplanner). It was concluded that the combination of SMART, the nature planner and OPS provide a good tool to develop and support policy on the local scale. 4 refs

  18. High Nitrogen Stainless Steel

    Science.gov (United States)

    2011-07-19

    crack growth (FCG) test (ASTM E 647-95a) - square bar specimen of 0.4x0.4x2.8 in. in L-orientation with a Charpy notch at the mid- length for SCC...Hydrogen Embrittlement in Steel by the Increment Loading Technique. Fractography: After the stress-life fatigue tests , the fracture surface morphology...NAWCADPAX/TR-2011/162 HIGH NITROGEN STAINLESS STEEL by E. U. Lee R. Taylor 19 July 2011 Approved for

  19. Is nitrogen the next carbon?

    Science.gov (United States)

    Battye, William; Aneja, Viney P.; Schlesinger, William H.

    2017-09-01

    Just as carbon fueled the Industrial Revolution, nitrogen has fueled an Agricultural Revolution. The use of synthetic nitrogen fertilizers and the cultivation of nitrogen-fixing crops both expanded exponentially during the last century, with most of the increase occurring after 1960. As a result, the current flux of reactive, or fixed, nitrogen compounds to the biosphere due to human activities is roughly equivalent to the total flux of fixed nitrogen from all natural sources, both on land masses and in the world's oceans. Natural fluxes of fixed nitrogen are subject to very large uncertainties, but anthropogenic production of reactive nitrogen has increased almost fivefold in the last 60 years, and this rapid increase in anthropogenic fixed nitrogen has removed any uncertainty on the relative importance of anthropogenic fluxes to the natural budget. The increased use of nitrogen has been critical for increased crop yields and protein production needed to keep pace with the growing world population. However, similar to carbon, the release of fixed nitrogen into the natural environment is linked to adverse consequences at local, regional, and global scales. Anthropogenic contributions of fixed nitrogen continue to grow relative to the natural budget, with uncertain consequences.

  20. Nitrate and Nitrogen Oxides: Sources, Health Effects and Their Remediation.

    Science.gov (United States)

    Hakeem, Khalid Rehman; Sabir, Muhammad; Ozturk, Munir; Akhtar, Mohd Sayeed; Ibrahim, Faridah Hanum

    Increased use of nitrogenous (N) fertilizers in agriculture has significantly altered the global N-cycle because they release nitrogenous gases of environmental concerns. The emission of nitrous oxide (N 2 O) contributes to the global greenhouse gas accumulation and the stratospheric ozone depletion. In addition, it causes nitrate leaching problem deteriorating ground water quality. The nitrate toxicity has been reported in a number of studies showing the health hazards like methemoglobinemia in infants and is a potent cause of cancer. Despite these evident negative environmental as well as health impacts, consumption of N fertilizer cannot be reduced in view of the food security for the teeming growing world population. Various agronomic and genetic modifications have been practiced to tackle this problem. Some agronomic techniques adopted include split application of N, use of slow-release fertilizers, nitrification inhibitors and encouraging the use of organic manure over chemical fertilizers. As a matter of fact, the use of chemical means to remediate nitrate from the environment is very difficult and costly. Particularly, removal of nitrate from water is difficult task because it is chemically non-reactive in dilute aqueous solutions. Hence, the use of biological means for nitrate remediation offers a promising strategy to minimize the ill effects of nitrates and nitrites. One of the important goals to reduce N-fertilizer application can be effectively achieved by choosing N-efficient genotypes. This will ensure the optimum uptake of applied N in a balanced manner and exploring the molecular mechanisms for their uptake as well as metabolism in assimilatory pathways. The objectives of this paper are to evaluate the interrelations which exist in the terrestrial ecosystems between the plant type and characteristics of nutrient uptake and analyze the global consumption and demand for fertilizer nitrogen in relation to cereal production, evaluate the various

  1. Phytoremediation of Nitrogen as Green Chemistry for Wastewater Treatment System

    Directory of Open Access Journals (Sweden)

    Lennevey Kinidi

    2017-01-01

    Full Text Available It is noteworthy that ammoniacal nitrogen contamination in wastewater has reportedly posed a great threat to the environment. Although there are several conventional technologies being employed to remediate ammoniacal nitrogen contamination in wastewater, they are not sustainable and cost-effective. Along this line, the present study aims to highlight the significance of green chemistry characteristics of phytoremediation in nitrogen for wastewater treatment. Notably, ammoniacal nitrogen can be found in many types of sources and it brings harmful effects to the environment. Hence, the present study also reviews the phytoremediation of nitrogen and describes its green chemistry characteristics. Additionally, the different types of wastewater contaminants and their effects on phytoremediation and the phytoremediation consideration in wastewater treatment application and sustainable waste management of harvested aquatic macrophytes were reviewed. Finally, the present study explicates the future perspectives of phytoremediation. Based on the reviews, it can be concluded that green chemistry characteristics of phytoremediation in nitrogen have proved that it is sustainable and cost-effective in relation to other existing ammoniacal nitrogen remediation technologies. Therefore, it can be deduced that a cheaper and more environmental friendly ammoniacal nitrogen technology can be achieved with the utilization of phytoremediation in wastewater treatment.

  2. Nitrogen requirements of commercial wine yeast strains during fermentation of a synthetic grape must.

    Science.gov (United States)

    Gutiérrez, Alicia; Chiva, Rosana; Sancho, Marta; Beltran, Gemma; Arroyo-López, Francisco Noé; Guillamon, José Manuel

    2012-08-01

    Nitrogen deficiencies in grape musts are one of the main causes of stuck or sluggish wine fermentations. Currently, the most common method for dealing with nitrogen-deficient fermentations is adding supplementary nitrogen (usually ammonium phosphate). However, it is important to know the specific nitrogen requirement of each strain, to avoid excessive addition that can lead to microbial instability and ethyl carbamate accumulation. In this study, we aimed to determine the effect of increasing nitrogen concentrations of three different nitrogen sources on growth and fermentation performance in four industrial wine yeast strains. This task was carried out using statistical modeling techniques. The strains PDM and RVA showed higher growth-rate and maximum population size and consumed nitrogen much more quickly than strains ARM and TTA. Likewise, the strains PDM and RVA were also the greatest nitrogen demanders. Thus, we can conclude that these differences in nitrogen demand positively correlated with higher growth rate and higher nitrogen uptake rate. The most direct effect of employing an adequate nitrogen concentration is the increase in biomass, which involves a higher fermentation rate. However, the impact of nitrogen on fermentation rate is not exclusively due to the increase in biomass because the strain TTA, which showed the worst growth behavior, had the best fermentation activity. Some strains may adapt a strategy whereby fewer cells with higher metabolic activity are produced. Regarding the nitrogen source used, all the strains showed the better and worse fermentation performance with arginine and ammonium, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. The geobiological nitrogen cycle: From microbes to the mantle.

    Science.gov (United States)

    Zerkle, A L; Mikhail, S

    2017-05-01

    Nitrogen forms an integral part of the main building blocks of life, including DNA, RNA, and proteins. N 2 is the dominant gas in Earth's atmosphere, and nitrogen is stored in all of Earth's geological reservoirs, including the crust, the mantle, and the core. As such, nitrogen geochemistry is fundamental to the evolution of planet Earth and the life it supports. Despite the importance of nitrogen in the Earth system, large gaps remain in our knowledge of how the surface and deep nitrogen cycles have evolved over geologic time. Here, we discuss the current understanding (or lack thereof) for how the unique interaction of biological innovation, geodynamics, and mantle petrology has acted to regulate Earth's nitrogen cycle over geologic timescales. In particular, we explore how temporal variations in the external (biosphere and atmosphere) and internal (crust and mantle) nitrogen cycles could have regulated atmospheric pN 2 . We consider three potential scenarios for the evolution of the geobiological nitrogen cycle over Earth's history: two in which atmospheric pN 2 has changed unidirectionally (increased or decreased) over geologic time and one in which pN 2 could have taken a dramatic deflection following the Great Oxidation Event. It is impossible to discriminate between these scenarios with the currently available models and datasets. However, we are optimistic that this problem can be solved, following a sustained, open-minded, and multidisciplinary effort between surface and deep Earth communities. © 2017 The Authors Geobiology Published by John Wiley & Sons Ltd.

  4. Addition of nitrogen had no effect on yield and quality of apples in an high density orchard carrying a dwarf rootstock A adição de nitrogênio não afetou o rendimento e a qualidade de maçãs em pomar com alta densidade e porta-enxerto anão

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Ernani

    2008-12-01

    Full Text Available The effect of N addition on apple yield and quality may vary according to the tree vigor. Apple trees developed over vigorous rootstocks had shown no response to N application in Brazil. In this study it was evaluated the effect of N addition to the soil on yield and quality of ´Royal Gala´ apples grafted on a dwarf rootstock (M.9. The orchard was planted in 1995 (2,857 trees ha-1 on an Oxisol containing 40 g kg-1 of organic matter and pH 6.0. The experiment was carried out from 1998 up to 2005. Treatments consisted of rates of N (0, 50, 100 and 150 kg ha-1 year-1 from 1998 to 2001, and respectively 0, 100, 200 and 300 kg ha-1 afterwards, all broadcasted within the tree row in two equal splits, at bud break and after harvest, as ammonium sulfate. Addition of N to the soil had no effect on fruit yield over the six years regardless of the applied rate. Averaged across treatments and years, fruit yield was 52.3 t ha-1. Nitrogen in the leaves (average of 24 g kg-1 or in the fruits (average of 346 mg kg-1 as well as some attributes related to fruit quality (color, firmness, acidity, soluble solids, physiological disorders were unaffected by N addition. Some plant parameters related to tree vigor, however, grew higher with the increase on N rate. Thus, it is not necessary to apply N to deep Brazilian soils containing high organic matter in order to assure good fruit quality and yield on high-density orchards carrying dwarf rootstocks probably because the N required for tree growth and fruit production is supplied from soil organic matter decay.O efeito da adição de N ao solo no rendimento e na qualidade de maçãs pode variar em função do vigor das plantas. Experimentos conduzidos no Brasil com macieiras cultivadas sobre porta-enxertos vigorosos não têm apresentado aumento no rendimento de frutos pela aplicação de N. Este trabalho objetivou avaliar o efeito da aplicação de N no rendimento e na qualidade de frutos de macieira cultivada em

  5. 21 CFR 862.1515 - Nitrogen (amino-nitrogen) test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitrogen (amino-nitrogen) test system. 862.1515... Systems § 862.1515 Nitrogen (amino-nitrogen) test system. (a) Identification. A nitrogen (amino-nitrogen) test system is a device intended to measure amino acid nitrogen levels in serum, plasma, and urine...

  6. Nitrogen and Oxygen Isotopic Studies of the Marine Nitrogen Cycle.

    Science.gov (United States)

    Casciotti, Karen L

    2016-01-01

    The marine nitrogen cycle is a complex web of microbially mediated reactions that control the inventory, distribution, and speciation of nitrogen in the marine environment. Because nitrogen is a major nutrient that is required by all life, its availability can control biological productivity and ecosystem structure in both surface and deep-ocean communities. Stable isotopes of nitrogen and oxygen in nitrate and nitrite have provided new insights into the rates and distributions of marine nitrogen cycle processes, especially when analyzed in combination with numerical simulations of ocean circulation and biogeochemistry. This review highlights the insights gained from dual-isotope studies applied at regional to global scales and their incorporation into oceanic biogeochemical models. These studies represent significant new advances in the use of isotopic measurements to understand the modern nitrogen cycle, with implications for the study of past ocean productivity, oxygenation, and nutrient status.

  7. Effects of nitrogen atoms of benzotriazole and its derivatives on the properties of electrodeposited Cu films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hoe Chul; Kim, Myung Jun; Lim, Taeho; Park, Kyung Ju; Kim, Kwang Hwan; Choe, Seunghoe [School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Gwanak 1, Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Kim, Soo-Kil, E-mail: sookilkim@cau.ac.kr [School of Integrative Engineering, Chung-Ang University, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756 (Korea, Republic of); Kim, Jae Jeong, E-mail: jjkimm@snu.ac.kr [School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Gwanak 1, Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2014-01-01

    Additives having azole groups with different numbers of nitrogen atoms, such as indole, benzimidazole, indazole, benzotriazole (BTA), and 1H-benzotriazole-methanol (BTA-MeOH) were adopted to improve the mechanical hardness of electrodeposited Cu films. The effects of these additives on the film properties were elucidated in relation to their number of nitrogen atoms. Electrochemical current–potential behaviors showed that the additives containing three nitrogen atoms (BTA and BTA-MeOH) more effectively inhibited Cu electrodeposition. The inhibition strongly affected the film properties, resulting in reduced grain size and surface roughness, and increased resistivity and hardness. Cu films deposited with BTA or BTA-MeOH also exhibited 35% reduced grain size and 1.5-time higher hardness than Cu films deposited in electrolyte containing other BTA-derivatives having fewer nitrogen atoms. This notable grain refining effect of BTA and BTA-MeOH can be evaluated with respect to the strong interaction of their nitrogen atoms with the substrate and the copper ions, as well. - Highlights: • Additives of similar structure containing 1, 2, and 3 nitrogen atoms were used. • Additives with 3 nitrogen atoms more strongly inhibited Cu deposition than others. • Additives containing 3 nitrogen atoms efficiently affected film properties. • Additives having 3 nitrogen atoms remarkably improved film hardness.

  8. Effect of nitrogen on the corrosion behavior of austenitic stainless steel in chloride solutions

    International Nuclear Information System (INIS)

    Ghanem, Wafaa A.

    2004-01-01

    The effect of partial replacement of nickel with nitrogen on the mechanism of localized corrosion resistance and re-passivation for nitrogen-bearing stainless steel was investigated using anodic potentiodynamic polarization technique. The solutions used for this study contained 0.0, 0.05 and 0.33 M Fe 3+ for solutions I, II and III respectively, in a total Cl - ion concentration 1 M. The pitting attack was found to be retarded by nitrogen addition and the samples were able to passivate as the nitrogen increase. Addition of nitrogen allows decreasing the percentage of Ni, but to a certain limit. Nitrogen is adsorbed on the interface of the metal oxide and results in repulsion of Cl - ions. Moreover, it reacts with H + ions in the solution leading to higher pH, which explains the retardation effect of nitrogen to corrosion. (author)

  9. Nitrogen supply of crops by biological nitrogen fixation. 2

    International Nuclear Information System (INIS)

    Jensen, E.S.; Andersen, A.J.; Soerensen, H.; Thomsen, J.D.

    1985-02-01

    In the present work the contributions from combined N-sources and symbiotic nitrogen fixation to the nitrogen supply of field-grown peas and field beans were evaluated by means of 15 N fertilizer dilution. The effect of N-fertilizer, supplied at sowing and at different stages of plant development, on nitrogen fixation, yield and protein production in peas, was studied in pot experiments. (author)

  10. Key ecological responses to nitrogen are altered by climate change

    Science.gov (United States)

    Greaver, T.L.; Clark, C.M.; Compton, J.E.; Vallano, D.; Talhelm, A. F.; Weaver, C.P.; Band, L.E.; Baron, Jill S.; Davidson, E.A.; Tague, C.L.; Felker-Quinn, E.; Lynch, J.A.; Herrick, J.D.; Liu, L.; Goodale, C.L.; Novak, K. J.; Haeuber, R. A.

    2016-01-01

    Climate change and anthropogenic nitrogen deposition are both important ecological threats. Evaluating their cumulative effects provides a more holistic view of ecosystem vulnerability to human activities, which would better inform policy decisions aimed to protect the sustainability of ecosystems. Our knowledge of the cumulative effects of these stressors is growing, but we lack an integrated understanding. In this Review, we describe how climate change alters key processes in terrestrial and freshwater ecosystems related to nitrogen cycling and availability, and the response of ecosystems to nitrogen addition in terms of carbon cycling, acidification and biodiversity.

  11. Reduced turning frequency and delayed poultry manure addition reduces N loss from sugarcane compost

    DEFF Research Database (Denmark)

    Bryndum, Sofie; Muschler, R.; Nigatu, Abebe Nigussie

    2017-01-01

    Composting is an effective method to recycle biodegradable waste as soil amendment in smallholder farming systems. Although all essential plant nutrients are found in compost, a substantial amount of nitrogen is lost during composting. This study therefore investigated the potential of reducing N...... losses by (i) delaying the addition of nitrogen-rich substrates (i.e. poultry manure), and (ii) reducing the turning frequency during composting. Furthermore, we tested the effect of compost application method on nitrogen mineralization. Sugarcane-waste was composted for 54days with addition of poultry...... of compost application on nitrogen mineralization. The results showed that delayed addition of poultry manure reduced total nitrogen loss by 33% and increased mineral nitrogen content by >200% compared with early addition. Similarly, less frequent turning reduced total N loss by 12% compared with frequent...

  12. Atomic state and characterization of nitrogen at the SiC/SiO2 interface

    International Nuclear Information System (INIS)

    Xu, Y.; Garfunkel, E. L.; Zhu, X.; Lee, H. D.; Xu, C.; Shubeita, S. M.; Gustafsson, T.; Ahyi, A. C.; Sharma, Y.; Williams, J. R.; Lu, W.; Ceesay, S.; Tuttle, B. R.; Pantelides, S. T.; Wan, A.; Feldman, L. C.

    2014-01-01

    We report on the concentration, chemical bonding, and etching behavior of N at the SiC(0001)/SiO 2 interface using photoemission, ion scattering, and computational modeling. For standard NO processing of a SiC MOSFET, a sub-monolayer of nitrogen is found in a thin inter-layer between the substrate and the gate oxide (SiO 2 ). Photoemission shows one main nitrogen related core-level peak with two broad, higher energy satellites. Comparison to theory indicates that the main peak is assigned to nitrogen bound with three silicon neighbors, with second nearest neighbors including carbon, nitrogen, and oxygen atoms. Surprisingly, N remains at the surface after the oxide was completely etched by a buffered HF solution. This is in striking contrast to the behavior of Si(100) undergoing the same etching process. We conclude that N is bound directly to the substrate SiC, or incorporated within the first layers of SiC, as opposed to bonding within the oxide network. These observations provide insights into the chemistry and function of N as an interface passivating additive in SiC MOSFETs

  13. [Factor analysis of interactions between alfalfa nodule bacteria (Sinorhizobium meliloti) genes that regulate symbiotic nitrogen fixation].

    Science.gov (United States)

    Provorov, N A; Chuklina, E; Vorob'ev, N I; Onishchuk, O P; Simarov, B V

    2013-04-01

    Factor analysis has been conducted for the data on the interaction between the genes of the root nodule bacteria (rhizobia), which influence the efficiency of symbiosis with leguminous plants, including dctA (encoding succinate permease), dctBD (activating the dctA gene due to binding its enhancer in the presence of succinate), rpoN (activating the promoters of dctA and nitrogenase genes nifHDK), and nifA (activating the nitrogenase genes due to binding their enhancers). The analysis of the alfalfa rhizobia (Sinorhizobium meliloti) recombinants that contain additional copies ofthese genes suggested the antagonistic (epistatic) interaction between nifA and rpoN. It may be associated either with the competition for C compounds imported into the nodules between the energy production and nitrogen assimilation processes or with the competition for redox potentials between the oxidative phosphorylation and nitrogen fixation processes. Since the phenotypic effects of the studied genes depend on the activity of nitrogen export into the aerial parts of plants, we suppose that its accumulation in bacteroids impairs the activation of the nifHDK genes by the NifA protein due to its interaction with the GlnB protein (the nitrogen metabolism regulator) or with the FixLJ and ActSR proteins (the redox potential regulators).

  14. Production of polyhydroxybutyrate and alginate from glycerol by Azotobacter vinelandii under nitrogen-free conditions.

    Science.gov (United States)

    Yoneyama, Fuminori; Yamamoto, Mayumi; Hashimoto, Wataru; Murata, Kousaku

    2015-01-01

    Glycerol is an interesting feedstock for biomaterials such as biofuels and bioplastics because of its abundance as a by-product during biodiesel production. Here we demonstrate glycerol metabolism in the nitrogen-fixing species Azotobacter vinelandii through metabolomics and nitrogen-free bacterial production of biopolymers, such as poly-d-3-hydroxybutyrate (PHB) and alginate, from glycerol. Glycerol-3-phosphate was accumulated in A. vinelandii cells grown on glycerol to the exponential phase, and its level drastically decreased in the cells grown to the stationary growth phase. A. vinelandii also overexpressed the glycerol-3-phosphate dehydrogenase gene when it was grown on glycerol. These results indicate that glycerol was first converted to glycerol-3-phosphate by glycerol kinase. Other molecules with industrial interests, such as lactic acid and amino acids including γ-aminobutyric acid, have also been accumulated in the bacterial cells grown on glycerol. Transmission electron microscopy revealed that glycerol-grown A. vinelandii stored PHB within the cells. The PHB production level reached 33% per dry cell weight in nitrogen-free glycerol medium. When grown on glycerol, alginate-overproducing mutants generated through chemical mutagenesis produced 2-fold the amount of alginate from glycerol than the parental wild-type strain. To the best of our knowledge, this is the first report on bacterial production of biopolymers from glycerol without addition of any nitrogen source.

  15. Analysis of alternative pathways for reducing nitrogen oxide emissions

    Science.gov (United States)

    Strategies for reducing tropospheric ozone typically include modifying combustion processes to reduce the formation of nitrogen oxides (NOx) and applying control devices that remove NOx from the exhaust gases of power plants, industrial sources and vehicles. For portions of the ...

  16. Ordered Semiconducting Nitrogen-Graphene Alloys

    OpenAIRE

    H. J. Xiang; B. Huang; Z. Y. Li; S.-H. Wei; J. L. Yang; X. G. Gong

    2012-01-01

    The interaction between substitutional nitrogen atoms in graphene is studied by performing first-principles calculations. The effective nearest-neighbor interaction between nitrogen dopants is found to be highly repulsive because of the strong electrostatic repulsion between nitrogen atoms. This interaction prevents the full nitrogen-carbon phase separation in nitrogen-doped graphene. Interestingly, there are two relatively stable nitrogen-nitrogen pair configurations, whose stability can be ...

  17. Dimensions of biodiversity of oceanic nitrogen cycling: nutrient co-limitation, nitrogen substrate preferences and more.

    Science.gov (United States)

    Zehr, J.; Mills, M. M.; Shilova, I. N.; Turk-Kubo, K.; Robidart, J.; van Dijken, G.; Bjorkman, K. M.; Whitt, D. B.; Wai, B.; Pampin Baro, J.; Hogan, M.; Rapp, I.; Zakem, E.; Fredrickson, A.; Leahy, B.; Linney, M.; Santiago, A.; Follows, M. J.; Achterberg, E. P.; Kolber, Z.; Church, M. J.; Arrigo, K. R.

    2016-02-01

    We conducted the research cruise: Nutrient Effects on Marine microOrganisms (NEMO) onboard the R/V New Horizon (NH1417: August 18 to September 16, 2014) between the ports of San Diego, CA and Honolulu, HI. The three major objectives of the cruise were to: 1) evaluate genetic, physiological and phylogenetic responses of marine phytoplankton communities in the North Pacific Subtropical Gyre to different nitrogen (N) substrates and to determine how other nutrients (iron, phosphorus) impact N utilization; 2) characterize the physical processes and dynamics in support of the biological processes; and 3) characterize the diversity and activities of microbial communities in the upper water column in relation to the nutrient availability. Several incubation experiments were conducted along the cruise transect to assess the effect of nutrients on microbial communities. The results showed that N addition resulted in increased chlorophyll a (chl a) and rates of CO2 fixation at most sites, but Prochlorococcus, Synechococcus and picoekaryotic phytoplankton had different responses to urea, ammonium and nitrate. In contrast, chl a and CO2 fixation did not respond to additions of single nutrient (e.g. N, P or Fe alone) at the westernmost experiment (151°W), where the simultaneous addition of N and P was required for stimulation. The physical dynamics were studied through high-resolution surveys of eddy dipole features as well as diel sampling at two locations. Additionally, we characterized an extensive bloom that occurred near the critical latitude (29°N, 140°W) from mid July to the end of September; a typical but still enigmatic event. Here, we present a summary of the initial observations and findings from the NEMO cruise with data including physics, nutrient concentrations, chl a, primary productivity and microbial community composition. The results of this research cruise will help in assessing how ocean N cycling and ecosystem functions will respond to global climate

  18. Terrestrial nitrogen-carbon cycle interactions at the global scale.

    Science.gov (United States)

    Zaehle, S

    2013-07-05

    Interactions between the terrestrial nitrogen (N) and carbon (C) cycles shape the response of ecosystems to global change. However, the global distribution of nitrogen availability and its importance in global biogeochemistry and biogeochemical interactions with the climate system remain uncertain. Based on projections of a terrestrial biosphere model scaling ecological understanding of nitrogen-carbon cycle interactions to global scales, anthropogenic nitrogen additions since 1860 are estimated to have enriched the terrestrial biosphere by 1.3 Pg N, supporting the sequestration of 11.2 Pg C. Over the same time period, CO2 fertilization has increased terrestrial carbon storage by 134.0 Pg C, increasing the terrestrial nitrogen stock by 1.2 Pg N. In 2001-2010, terrestrial ecosystems sequestered an estimated total of 27 Tg N yr(-1) (1.9 Pg C yr(-1)), of which 10 Tg N yr(-1) (0.2 Pg C yr(-1)) are due to anthropogenic nitrogen deposition. Nitrogen availability already limits terrestrial carbon sequestration in the boreal and temperate zone, and will constrain future carbon sequestration in response to CO2 fertilization (regionally by up to 70% compared with an estimate without considering nitrogen-carbon interactions). This reduced terrestrial carbon uptake will probably dominate the role of the terrestrial nitrogen cycle in the climate system, as it accelerates the accumulation of anthropogenic CO2 in the atmosphere. However, increases of N2O emissions owing to anthropogenic nitrogen and climate change (at a rate of approx. 0.5 Tg N yr(-1) per 1°C degree climate warming) will add an important long-term climate forcing.

  19. Nitrogen concentration estimation with hyperspectral LiDAR

    Directory of Open Access Journals (Sweden)

    O. Nevalainen

    2013-10-01

    Full Text Available Agricultural lands have strong impact on global carbon dynamics and nitrogen availability. Monitoring changes in agricultural lands require more efficient and accurate methods. The first prototype of a full waveform hyperspectral Light Detection and Ranging (LiDAR instrument has been developed at the Finnish Geodetic Institute (FGI. The instrument efficiently combines the benefits of passive and active remote sensing sensors. It is able to produce 3D point clouds with spectral information included for every point which offers great potential in the field of remote sensing of environment. This study investigates the performance of the hyperspectral LiDAR instrument in nitrogen estimation. The investigation was conducted by finding vegetation indices sensitive to nitrogen concentration using hyperspectral LiDAR data and validating their performance in nitrogen estimation. The nitrogen estimation was performed by calculating 28 published vegetation indices to ten oat samples grown in different fertilization conditions. Reference data was acquired by laboratory nitrogen concentration analysis. The performance of the indices in nitrogen estimation was determined by linear regression and leave-one-out cross-validation. The results indicate that the hyperspectral LiDAR instrument holds a good capability to estimate plant biochemical parameters such as nitrogen concentration. The instrument holds much potential in various environmental applications and provides a significant improvement to the remote sensing of environment.

  20. Regulatory networks controlling nitrogen sensing and uptake in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Shruthi Ramachandra

    Full Text Available Nitrogen is one of the key nutrients for microbial growth. During infection, pathogenic fungi like C. albicans need to acquire nitrogen from a broad range of different and changing sources inside the host. Detecting the available nitrogen sources and adjusting the expression of genes for their uptake and degradation is therefore crucial for survival and growth as well as for establishing an infection. Here, we analyzed the transcriptional response of C. albicans to nitrogen starvation and feeding with the infection-relevant nitrogen sources arginine and bovine serum albumin (BSA, representing amino acids and proteins, respectively. The response to nitrogen starvation was marked by an immediate repression of protein synthesis and an up-regulation of general amino acid permeases, as well as an up-regulation of autophagal processes in its later stages. Feeding with arginine led to a fast reduction in expression of general permeases for amino acids and to resumption of protein synthesis. The response to BSA feeding was generally slower, and was additionally characterized by an up-regulation of oligopeptide transporter genes. From time-series data, we inferred network interaction models for genes relevant in nitrogen detection and uptake. Each individual network was found to be largely specific for the experimental condition (starvation or feeding with arginine or BSA. In addition, we detected several novel connections between regulator and effector genes, with putative roles in nitrogen uptake. We conclude that C. albicans adopts a particular nitrogen response network, defined by sets of specific gene-gene connections for each environmental condition. All together, they form a grid of possible gene regulatory networks, increasing the transcriptional flexibility of C. albicans.

  1. Regulatory networks controlling nitrogen sensing and uptake in Candida albicans.

    Science.gov (United States)

    Ramachandra, Shruthi; Linde, Jörg; Brock, Matthias; Guthke, Reinhard; Hube, Bernhard; Brunke, Sascha

    2014-01-01

    Nitrogen is one of the key nutrients for microbial growth. During infection, pathogenic fungi like C. albicans need to acquire nitrogen from a broad range of different and changing sources inside the host. Detecting the available nitrogen sources and adjusting the expression of genes for their uptake and degradation is therefore crucial for survival and growth as well as for establishing an infection. Here, we analyzed the transcriptional response of C. albicans to nitrogen starvation and feeding with the infection-relevant nitrogen sources arginine and bovine serum albumin (BSA), representing amino acids and proteins, respectively. The response to nitrogen starvation was marked by an immediate repression of protein synthesis and an up-regulation of general amino acid permeases, as well as an up-regulation of autophagal processes in its later stages. Feeding with arginine led to a fast reduction in expression of general permeases for amino acids and to resumption of protein synthesis. The response to BSA feeding was generally slower, and was additionally characterized by an up-regulation of oligopeptide transporter genes. From time-series data, we inferred network interaction models for genes relevant in nitrogen detection and uptake. Each individual network was found to be largely specific for the experimental condition (starvation or feeding with arginine or BSA). In addition, we detected several novel connections between regulator and effector genes, with putative roles in nitrogen uptake. We conclude that C. albicans adopts a particular nitrogen response network, defined by sets of specific gene-gene connections for each environmental condition. All together, they form a grid of possible gene regulatory networks, increasing the transcriptional flexibility of C. albicans.

  2. Global transcriptional analysis of nitrogen fixation and ammonium repression in root-associated Pseudomonas stutzeri A1501

    Directory of Open Access Journals (Sweden)

    Lu Wei

    2010-01-01

    Full Text Available Abstract Background Biological nitrogen fixation is highly controlled at the transcriptional level by regulatory networks that respond to the availability of fixed nitrogen. In many diazotrophs, addition of excess ammonium in the growth medium results in immediate repression of nif gene transcription. Although the regulatory cascades that control the transcription of the nif genes in proteobacteria have been well investigated, there are limited data on the kinetics of ammonium-dependent repression of nitrogen fixation. Results Here we report a global transcriptional profiling analysis of nitrogen fixation and ammonium repression in Pseudomonas stutzeri A1501, a root-associated and nitrogen-fixing bacterium. A total of 166 genes, including those coding for the global nitrogen regulation (Ntr and Nif-specific regulatory proteins, were upregulated under nitrogen fixation conditions but rapidly downregulated as early as 10 min after ammonium shock. Among these nitrogen fixation-inducible genes, 95 have orthologs in each of Azoarcus sp. BH72 and Azotobacter vinelandii AvoP. In particular, a 49-kb expression island containing nif and other associated genes was markedly downregulated by ammonium shock. Further functional characterization of pnfA, a new NifA-σ54-dependent gene chromosomally linked to nifHDK, is reported. This gene encodes a protein product with an amino acid sequence similar to that of five hypothetical proteins found only in diazotrophic strains. No noticeable differences in the transcription of nifHDK were detected between the wild type strain and pnfA mutant. However, the mutant strain exhibited a significant decrease in nitrogenase activity under microaerobic conditions and lost its ability to use nitrate as a terminal electron acceptor for the support of nitrogen fixation under anaerobic conditions. Conclusions Based on our results, we conclude that transcriptional regulation of nif gene expression in A1501 is mediated by the nif

  3. Effect of Nitrogen on Transformation Behaviors and Microstructure of V-N Microalloyed Steel

    Science.gov (United States)

    Zhao, Baochun; Zhao, Tan; Li, Guiyan; Lu, Qiang

    Multi-pass deformation simulation tests were performed on V-N microalloyed steels with different nitrogen addition by using a Gleeble-3800 thermo-mechanical simulator and the corresponding continuous cooling transformation (CCT) diagrams were determined by thermal dilation method and metallographic method. The deformed austenite transformation behavior and resultant microstructure of the tested steels were studied. Furthermore, the effect of nitrogen addition on the transformation behavior and microstructure evolution was analyzed. The results show that the transformed microstructures in the three tested steels are ferrite, pearlite and bainite respectively while the transformation temperatures are not the same. For the two tested steel with higher nitrogen additions, higher ferrite start temperature and critical cooling rates are observed. Furthermore, an increase in nitrogen addition leads to increasing quantities of ferrite and the transformed ferrite is smaller in size. The hardness test results reveal that the hardness number increases with increasing nitrogen addition at low cooling rate while the value tends to be smaller due to increasing nitrogen addition at high cooling rate. Therefore, the hardness number of the steel with high nitrogen addition is not so sensitive to cooling rate as that of the steel with low nitrogen addition.

  4. Nitrogen accumulation and residual effects of nitrogen catch crops

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1991-01-01

    The nitrogen accumulation in Italian ryegrass (Lolium multiflorum Lam.), perennial ryegrass (Lolium perenne L.), white mustard (Sinapis alba L.) and tansy phacelia (Phacelia tanacetifolia L.), under- or aftersown as nitrogen catch crops to spring barley (Hordeum vulgare L.) and field pea (Pisum...

  5. Nitrogen remobilization in wheat as influenced by nitrogen ...

    African Journals Online (AJOL)

    Pre-anthesis stored nitrogen in wheat (Triticum aestivum L.) is important because grain filling greatly depends on the remobilization of pre-anthesis nitrogen under Mediterranean growth conditions. This field study was conducted to assess the effect of post-anthesis water deficit and three N fertilizer levels on N ...

  6. Effect of nitrogen levels and nitrogen ratios on lodging resistance and yield potential of winter wheat (Triticum aestivum L.).

    Science.gov (United States)

    Zhang, Mingwei; Wang, Hui; Yi, Yuan; Ding, Jinfeng; Zhu, Min; Li, Chunyan; Guo, Wenshan; Feng, Chaonian; Zhu, Xinkai

    2017-01-01

    Lodging is one of the constraints that limit wheat yields and quality due to the unexpected bending or breaking stems on wheat (Triticum aestivum L.) production worldwide. In addition to choosing lodging resistance varieties, husbandry practices also have a significant effect on lodging. Nitrogen management is one of the most common and efficient methods. A field experiment with Yangmai 20 as research material (a widely-used variety) was conducted to study the effects of different nitrogen levels and ratios on culm morphological, anatomical characters and chemical components and to explore the nitrogen application techniques for lodging tolerance and high yield. Results showed that some index of basal internodes, such as stem wall thickness, filling degree, lignin content, cellulose content, water-soluble carbohydrate (WSC) and WSC/N ratio, were positively and significantly correlated with culm lodging-resistant index (CLRI). As the increase of nitrogen level and basal nitrogen ratio, the basal internodes became slender and fragile with the thick stem wall, while filling degree, chemical components and the strength of the stem decreased gradually, which significantly increased the lodging risk. The response of grain yield to nitrogen doses was quadratic and grain yield reached the highest at the nitrogen ratio of 50%:10%:20%:20% (the ratio of nitrogen amount applied before sowing, at tillering stage, jointing stage and booting stage respectively, abbreviated as 5:1:2:2). These results suggested that for Yangmai 20, the planting density of 180×104ha-1, nitrogen level of 225 kg ha-1, and the ratio of 5: 1: 2: 2 effectively increased lodging resistance and grain yield. This combination of planting density and nitrogen level and ratio could effectively relieve the contradiction between high-yielding and anti-lodging.

  7. Effect of nitrogen levels and nitrogen ratios on lodging resistance and yield potential of winter wheat (Triticum aestivum L..

    Directory of Open Access Journals (Sweden)

    Mingwei Zhang

    Full Text Available Lodging is one of the constraints that limit wheat yields and quality due to the unexpected bending or breaking stems on wheat (Triticum aestivum L. production worldwide. In addition to choosing lodging resistance varieties, husbandry practices also have a significant effect on lodging. Nitrogen management is one of the most common and efficient methods. A field experiment with Yangmai 20 as research material (a widely-used variety was conducted to study the effects of different nitrogen levels and ratios on culm morphological, anatomical characters and chemical components and to explore the nitrogen application techniques for lodging tolerance and high yield. Results showed that some index of basal internodes, such as stem wall thickness, filling degree, lignin content, cellulose content, water-soluble carbohydrate (WSC and WSC/N ratio, were positively and significantly correlated with culm lodging-resistant index (CLRI. As the increase of nitrogen level and basal nitrogen ratio, the basal internodes became slender and fragile with the thick stem wall, while filling degree, chemical components and the strength of the stem decreased gradually, which significantly increased the lodging risk. The response of grain yield to nitrogen doses was quadratic and grain yield reached the highest at the nitrogen ratio of 50%:10%:20%:20% (the ratio of nitrogen amount applied before sowing, at tillering stage, jointing stage and booting stage respectively, abbreviated as 5:1:2:2. These results suggested that for Yangmai 20, the planting density of 180×104ha-1, nitrogen level of 225 kg ha-1, and the ratio of 5: 1: 2: 2 effectively increased lodging resistance and grain yield. This combination of planting density and nitrogen level and ratio could effectively relieve the contradiction between high-yielding and anti-lodging.

  8. Biology of nitrogen oxides in the gastrointestinal tract.

    Science.gov (United States)

    Lundberg, Jon O; Weitzberg, Eddie

    2013-04-01

    Throughout the human gastrointestinal tract a variety of reactive nitrogen oxides are continuously formed as a result of a complex interplay between the host, commensal bacteria and dietary factors. These compounds include nitric oxide, nitrite, nitrate, peroxynitrite, S-nitrosothiols, nitrated fatty acids and N-nitrosamines, all of which are bioactive with the potential to affect physiological and pathological processes locally in the gut as well as systemically after absorption. Historically, the literature has been dominated by studies on the formation of potentially carcinogenic nitrosamines, but the focus was shifted in the 1980s with the seminal discovery of the L-arginine-nitric oxide pathway and its profound impact on normal physiological functions. More recently, a nitrate-nitrite-nitric oxide pathway has been discovered, with implications for local host defence and gut mucosal integrity and, intriguingly, also for systemic regulation of cardiovascular and metabolic function. This review discusses recent advances in the understanding of the formation, biochemistry, physiology and pathophysiology of reactive nitrogen oxides in the gastrointestinal tract. In addition, opportunities for nitric oxide-based pharmacological or dietary interventions are highlighted.

  9. Nitrogen deposition and its ecological impact in China: An overview

    International Nuclear Information System (INIS)

    Liu Xuejun; Duan Lei; Mo Jiangming; Du Enzai; Shen Jianlin; Lu Xiankai; Zhang Ying; Zhou Xiaobing; He Chune; Zhang Fusuo

    2011-01-01

    Nitrogen (N) deposition is an important component in the global N cycle that has induced large impacts on the health and services of terrestrial and aquatic ecosystems worldwide. Anthropogenic reactive N (N r ) emissions to the atmosphere have increased dramatically in China due to rapid agricultural, industrial and urban development. Therefore increasing N deposition in China and its ecological impacts are of great concern since the 1980s. This paper synthesizes the data from various published papers to assess the status of the anthropogenic N r emissions and N deposition as well as their impacts on different ecosystems, including empirical critical loads for different ecosystems. Research challenges and policy implications on atmospheric N pollution and deposition are also discussed. China urgently needs to establish national networks for N deposition monitoring and cross-site N addition experiments in grasslands, forests and aquatic ecosystems. Critical loads and modeling tools will be further used in N r regulation. - This paper reviews current knowledge on nitrogen deposition and its effects across China

  10. Nitrous oxide flux from landfill leachate-sawdust nitrogenous compost

    International Nuclear Information System (INIS)

    Hui, C.H.; So, M.K.; Lee, C.M.; Chan, G.Y.S.

    2003-01-01

    Composted nitrogenous waste has the potential to produce excessive amounts of nitrous oxide (N 2 O), a potent greenhouse gas that also contributes to stratospheric ozone depletion. In this laboratory study, sawdust was irrigated with varying amounts of landfill leachate with high NH 4 + -N content (3950 mg l -1 ). Physicochemical properties, including the amount of N 2 O produced, were monitored during the composting process over 28 days. A rapid decline in NH 4 + -N in the first 4 days and increasing NO 3 - -N for 11 days was followed by lower but stabilized levels of available-N, even with repeated leachate irrigation. Less than 0.03% of the leachate-applied N was lost as N 2 O. Higher leachate applications as much as tripled N 2 O production, but this represented a lesser proportion overall of the total nitrogen. Addition of glucose to the composting process had no significant effect on N 2 O production. The derived sawdust-leachate compost supported healthy growth of Sesbania rostrata. It is concluded that compost can be produced from sawdust irrigated with landfill leachate without substantial emission of N 2 O, although excessive flux of N 2 O remains about high application rates over longer time periods. (Author)

  11. Genetic Dissection of Root Morphological Traits Related to Nitrogen Use Efficiency in Brassica napus L. under Two Contrasting Nitrogen Conditions

    Directory of Open Access Journals (Sweden)

    Jie Wang

    2017-09-01

    Full Text Available As the major determinant for nutrient uptake, root system architecture (RSA has a massive impact on nitrogen use efficiency (NUE. However, little is known the molecular control of RSA as related to NUE in rapeseed. Here, a rapeseed recombinant inbred line population (BnaZNRIL was used to investigate root morphology (RM, an important component for RSA and NUE-related traits under high-nitrogen (HN and low-nitrogen (LN conditions by hydroponics. Data analysis suggested that RM-related traits, particularly root size had significantly phenotypic correlations with plant dry biomass and N uptake irrespective of N levels, but no or little correlation with N utilization efficiency (NUtE, providing the potential to identify QTLs with pleiotropy or specificity for RM- and NUE-related traits. A total of 129 QTLs (including 23 stable QTLs, which were repeatedly detected at least two environments or different N levels were identified and 83 of them were integrated into 22 pleiotropic QTL clusters. Five RM-NUE, ten RM-specific and three NUE-specific QTL clusters with same directions of additive-effect implied two NUE-improving approaches (RM-based and N utilization-based directly and provided valuable genomic regions for NUE improvement in rapeseed. Importantly, all of four major QTLs and most of stable QTLs (20 out of 23 detected here were related to RM traits under HN and/or LN levels, suggested that regulating RM to improve NUE would be more feasible than regulating N efficiency directly. These results provided the promising genomic regions for marker-assisted selection on RM-based NUE improvement in rapeseed.

  12. Assimilation of 15N-labelled urea nitrogen and ammonium nitrate nitrogen by plants in case of root and non-root fertilization

    International Nuclear Information System (INIS)

    Muravin, Eh.A.; Kozhemyachko, V.A.; Vernichenko, I.V.

    1974-01-01

    Assimilation of 15 N labeled urea and ammonium nitrate in root and foliar application by spring wheat and barley has been studied during 1970-1973 period in a series of vegetative experiments at the Department of Agrochemistry, Timiryazev Agricultural Academy, and at D.N. Pryanishnikov Experimental Agrochemical Station. Additional fertilizer nitrogen applied at later ontogenesis stages (flowering and milky ripeness) is utilized mostly for protein synthesis in developing grains, thus leading to a significant increase in the relative grain protein content. A transfer of a part of nitrogen from the main ortion of fertilizer at later stages of nitrition results, at the same time, in a lower yield. Nitrogen utilization degree of urea and ammonium nitrate, when introduced before sowing or at the flowering stage is similar but in the latter case, however, additional assimilation of soil nitrogen is lower. The assimilation rate of nitrogen in root application is the lower the later the fertilizer is applied. When ammonium nitrate is additionally applied as nutrition to barley at the milky ripeness stage, ammonia and nitrate nitrogen are assimilated at the same rate and to the same extent but ammonia nitrogen is more rapidly used for protein synthesis and the rate of its transfer to the developing grains is higher. The rate of nitrogen assimilation at plant is much higher in foliar than in root application. Wheat utilizes more urea nitrogen at the flowering stage when root application is used but at the milky ripeness stage foliar application is more effective

  13. Modelling Nitrogen Transformation in Horizontal Subsurface Flow ...

    African Journals Online (AJOL)

    Accretion of organic nitrogen was a major pathway accounting for 0.279 g/m2.d, which is 19.2% of all the influent nitrogen. The accumulation of ammonia nitrogen was found to be high compared to other water phase state variables (organic nitrogen and nitrate nitrogen). Journal of Civil Engineering Research and Practice ...

  14. Nitrogen implantation into silicon at 700-1100 deg C

    International Nuclear Information System (INIS)

    Kachurin, G.A.; Tyschenko, I.E.; Popov, V.P.; Tijs, S.A.; Plotnikov, A.E.

    1989-01-01

    Nitrogen ions 130-140 kW potential accelerated were implanted in silicon heated up to Ti=700-1100 deg C. Densities of ion current were 1-5 mcA/cm 2 , doses did not exceed 5x10 17 cm -2 . Initial stages of nitride formation in buried layers are investigated by means of Rutherford backscattering, layer-by-layer Augerspctroscopy and electron microscopy. It is determind, that Ti growth from 700 up to 900 deg C is accompanied by essential reduction of defectiveness of silicon near-the-surface layer at nitrogen retention within the limits of the calculation profile of ion ranges. At Ti=900 deg C nitrogen is rather mobile and at ∼5x10 16 cm -2 dose it is drown to α-Si 3 N 4 crystalling extraction in R p range. Beginning from Ti ≅1000 deg C nitrogen is not retained in the furied layer and diffuses to the surface. No essenstial losses of nitrogen due to evaporation or inside diffusion are observed. It is noted, that critical Ti, when nitrogen is accumulated in the buried layer, correspond to critical temperatures, when light ions introduce essential structure distortions. Conclusion is made, that irradition-introduced distortions of structure represent centres of initiation and growth of nitride phase. At 1150 deg C additional annaling during 3 hs nitrogen, occurring outside the stable extraction, is redistributed between th surface and furied layers, sintering in narrow concentration peaks

  15. Spectroscopic investigation of nitrogen-functionalized carbon materials

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Kevin N. [Department of Metallurgical and Materials Engineering, Colorado School of Mines, 1500 Illinois Street Golden CO 80401 USA; Department of Mechanical Engineering, University of Michigan, Ann Arbor MI 48109 USA; Christensen, Steven T. [National Renewable Energy Laboratory, 15013 Denver West Pkwy Golden CO 80401 USA; Nordlund, Dennis [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd Menlo Park CA 94023 USA; Dameron, Arrelaine A. [National Renewable Energy Laboratory, 15013 Denver West Pkwy Golden CO 80401 USA; Ngo, Chilan [Department of Chemistry and Geochemistry, Colorado School of Mines, 1012 14th Street Golden CO 80401 USA; Dinh, Huyen [National Renewable Energy Laboratory, 15013 Denver West Pkwy Golden CO 80401 USA; Gennett, Thomas [National Renewable Energy Laboratory, 15013 Denver West Pkwy Golden CO 80401 USA; O' Hayre, Ryan [Department of Metallurgical and Materials Engineering, Colorado School of Mines, 1500 Illinois Street Golden CO 80401 USA; Pylypenko, Svitlana [Department of Chemistry and Geochemistry, Colorado School of Mines, 1012 14th Street Golden CO 80401 USA

    2016-04-07

    Carbon materials are used in a diverse set of applications ranging from pharmaceuticals to catalysis. Nitrogen modification of carbon powders has shown to be an effective method for enhancing both surface and bulk properties of as-received material for a number of applications. Unfortunately, control of the nitrogen modification process is challenging and can limit the effectiveness and reproducibility of N-doped materials. Additionally, the assignment of functional groups to specific moieties on the surface of nitrogen-modified carbon materials is not straightforward. Herein, we complete an in-depth analysis of functional groups present at the surface of ion-implanted Vulcan and Graphitic Vulcan through the use of X-ray photoelectron spectroscopy (XPS) and near edge X-ray adsorption fine structure spectroscopy (NEXAFS). Our results show that regardless of the initial starting materials used, nitrogen ion implantation conditions can be tuned to increase the amount of nitrogen incorporation and to obtain both similar and reproducible final distributions of nitrogen functional groups. The development of a well-controlled/reproducible nitrogen implantation pathway opens the door for carbon supported catalyst architectures to have improved numbers of nucleation sites, decreased particle size, and enhanced catalyst-support interactions.

  16. Field estimation of the utilization coefficient of added inorganic nitrogen by sugar-beets

    International Nuclear Information System (INIS)

    Lindemann, Y.; Guiraud, G.; Christmann, J.; Auge, G.

    1981-07-01

    Fertilization with mineral nitrogen labelled with the 15 isotope permits, in the crop, the estimation of both: - the real utilization coefficient of N fertilizer, - the uptake of the available N issued from organic matter. In 1979, such an experiment was carried out on sugar beet in Beauce on a long term field experiment including 7 N.P.K. treatments with 4 repetitions. Each plot was divided into 2 parts to constitute a treatment N=0 for the estimation of the apparent utilization coefficient. In addition, 4 microplots (size: 8 m 2 ) received a labelled fertilizer for the measurement of the actual coefficients. The results obtained show the incoherence of the apparent coefficients, which are higher than 100%. The real coefficients are from 40 to 80%. Thus, the balance sheet for the input and output of mineral nitrogen is established precisely. The gross mineralization can be much more important than the net mineralization [fr

  17. Effects of nitrogen fertilization in cotton crop on Aphis gossypii Glover (Hemiptera: Aphididae) biology

    International Nuclear Information System (INIS)

    Barros, Ricardo; Degrande, Paulo E.; Fernandes, Marcos G.; Nogueira, Rodrigo F.

    2007-01-01

    The cotton aphid, Aphis gossypii Glove, is one of the pests of cotton crop and its relation with the host seem to depend on the amount of nitrogen available to the plant. The biology of A. gossypii using different cotton nitrogen fertility regimes was studied under greenhouse conditions, in Dourados, MS. A completely randomized design with nine replications in a factorial scheme (2x4x2)+1 was used. Two nitrogen sources (sulphate of ammonium and urea), four doses of nitrogen (50, 100, 150 and 200 kg ha-1), two different times of nitrogen application and one additional treatment without nitrogen were taken as factors. The nymphal phases, the pre-reproductive, reproductive and pos-reproductive periods, longevity, the life cycle and fecundity of the cotton aphid were evaluated. The doses of nitrogen influenced the cotton aphid biology in both sources and times of application, favoring its development and fecundity. (author)

  18. The Effect of Nitrogen and Plant Density on Some Growth Characteristics, Yield and Essential Oil in Peppermint (Mentha piperita L.

    Directory of Open Access Journals (Sweden)

    z Izadi

    2011-02-01

    Full Text Available Abstract In order to study the effect of different amounts of nitrogen and plant density on growth, yield, the percentage of essential oil in leaf and essential oil yield of peppermint (Mentha piperita L., an experiment was conducted in 2008 at the Experimental Field of the Agricultural Faculty of Bu-Ali Sina University. The experiment was split plot based on randomized complete block design with three replications over two cuts. The main plots included the amounts of 100, 150 and 200 kg nitrogen/ha in which half of fertilizer were used for the first cut and another half for the second. The sub-plots were consisted of plant densities as 8, 12 and 16 plants/m2. Morphophysiological characteristics including plant height, node and leaf number per plant, leaf area index, fresh and dry yield, essential oil percentage in leaf and essential oil yield over two cuts, and also the growth of dry matter, leaf area index and crop growth rate in the first cut were measured. The results showed that, nitrogen treatment significantly affected the properties measured, so that, their highest rates were obtained with the application of 100 and 200 kg nitrogen/ha from the first and the second cut, respectively. In addition, total dry matter, leaf area index and crop growth rate increased with increasing the amounts of nitrogen. Plant density also affected the plant height; node number, leaf number and leaf area index, essential oil percentage in leaf and essential oil yield in the first cut significantly, and in the second cut, plant density effect on leaf number and leaf area index was significant as well. Keywords: Peppermint, Nitrogen, Plant density, Yield, Growth indices, Essential oil

  19. Nitrogen-neutrality: a step towards sustainability

    Science.gov (United States)

    Leip, Adrian; Leach, Allison; Musinguzi, Patrick; Tumwesigye, Trust; Olupot, Giregon; Tenywa, John Stephen; Mudiope, Joseph; Hutton, Olivia; Cordovil, Claudia M. d. S.; Bekunda, Mateete; Galloway, James

    2014-11-01

    We propose a novel indicator measuring one dimension of the sustainability of an entity in modern societies: Nitrogen-neutrality. N-neutrality strives to offset Nr releases an entity exerts on the environment from the release of reactive nitrogen (Nr) to the environment by reducing it and by offsetting the Nr releases elsewhere. N-neutrality also aims to increase awareness about the consequences of unintentional releases of nitrogen to the environment. N-neutrality is composed of two quantified elements: Nr released by an entity (e.g. on the basis of the N footprint) and Nr reduction from management and offset projects (N offset). It includes management strategies to reduce nitrogen losses before they occur (e.g., through energy conservation). Each of those elements faces specific challenges with regard to data availability and conceptual development. Impacts of Nr releases to the environment are manifold, and the impact profile of one unit of Nr release depends strongly on the compound released and the local susceptibility to Nr. As such, N-neutrality is more difficult to conceptualize and calculate than C-neutrality. We developed a workable conceptual framework for N-neutrality which was adapted for the 6th International Nitrogen Conference (N2013, Kampala, November 2013). Total N footprint of the surveyed meals at N2013 was 66 kg N. A total of US 3050 was collected from the participants and used to offset the conference’s N footprint by supporting the UN Millennium Village cluster Ruhiira in South-Western Uganda. The concept needs further development in particular to better incorporate the spatio-temporal variability of impacts and to standardize the methods to quantify the required N offset to neutralize the Nr releases impact. Criteria for compensation projects need to be sharply defined to allow the development of a market for N offset certificates.

  20. Nitrogen-neutrality: a step towards sustainability

    International Nuclear Information System (INIS)

    Leip, Adrian; Leach, Allison; Hutton, Olivia; Galloway, James; Musinguzi, Patrick; Tumwesigye, Trust; Olupot, Giregon; Stephen Tenywa, John; Mudiope, Joseph; Cordovil, Claudia M d S; Bekunda, Mateete

    2014-01-01

    We propose a novel indicator measuring one dimension of the sustainability of an entity in modern societies: Nitrogen-neutrality. N-neutrality strives to offset Nr releases an entity exerts on the environment from the release of reactive nitrogen (Nr) to the environment by reducing it and by offsetting the Nr releases elsewhere. N-neutrality also aims to increase awareness about the consequences of unintentional releases of nitrogen to the environment. N-neutrality is composed of two quantified elements: Nr released by an entity (e.g. on the basis of the N footprint) and Nr reduction from management and offset projects (N offset). It includes management strategies to reduce nitrogen losses before they occur (e.g., through energy conservation). Each of those elements faces specific challenges with regard to data availability and conceptual development. Impacts of Nr releases to the environment are manifold, and the impact profile of one unit of Nr release depends strongly on the compound released and the local susceptibility to Nr. As such, N-neutrality is more difficult to conceptualize and calculate than C-neutrality. We developed a workable conceptual framework for N-neutrality which was adapted for the 6th International Nitrogen Conference (N2013, Kampala, November 2013). Total N footprint of the surveyed meals at N2013 was 66 kg N. A total of US$ 3050 was collected from the participants and used to offset the conference’s N footprint by supporting the UN Millennium Village cluster Ruhiira in South-Western Uganda. The concept needs further development in particular to better incorporate the spatio-temporal variability of impacts and to standardize the methods to quantify the required N offset to neutralize the Nr releases impact. Criteria for compensation projects need to be sharply defined to allow the development of a market for N offset certificates. (paper)

  1. The comparison of phosphorus-nitrogen and sulfur-phosphorus-nitrogen on the anti-flammability and thermal degradation of cotton fabrics

    Science.gov (United States)

    The phosphorus-nitrogen (P-N) or sulfur (S) containing compounds are well known for their effectiveness as flame retardant additives for many polymeric systems. When either phosphorus or nitrogen is combined with sulfur, the new systems prove to be successful combinations. This research aims to le...

  2. Impact of Temporary Nitrogen Deprivation on Tomato Leaf Phenolics

    Directory of Open Access Journals (Sweden)

    Hélène Gautier

    2011-11-01

    Full Text Available Reducing the use of pesticides represents a major challenge of modern agriculture. Plants synthesize secondary metabolites such as polyphenols that participate in the resistance to parasites. The aim of this study was to test: (1 the impact of nitrogen deficiency on tomato (Solanum lycopersicum leaf composition and more particularly on two phenolic molecules (chlorogenic acid and rutin as well as on the general plant biomass; and (2 whether this effect continued after a return to normal nitrogen nutrition. Our results showed that plants deprived of nitrogen for 10 or 19 days contained higher levels of chlorogenic acid and rutin than control plants. In addition, this difference persisted when the plants were once again cultivated on a nitrogen-rich medium. These findings offer interesting perspectives on the use of a short period of deprivation to modulate the levels of compounds of interest in a plant.

  3. Intracellular Nitrate of Marine Diatoms as a Driver of Anaerobic Nitrogen Cycling in Sinking Aggregates

    Directory of Open Access Journals (Sweden)

    Anja Kamp

    2016-11-01

    Full Text Available Diatom-bacteria aggregates are key for the vertical transport of organic carbon in the ocean. Sinking aggregates also represent pelagic microniches with intensified microbial activity, oxygen depletion in the center, and anaerobic nitrogen cycling. Since some of the aggregate-forming diatom species store nitrate intracellularly, we explored the fate of intracellular nitrate and its availability for microbial metabolism within anoxic diatom-bacteria aggregates. The ubiquitous nitrate-storing diatom Skeletonema marinoi was studied as both axenic cultures and laboratory-produced diatom-bacteria aggregates. Stable 15N isotope incubations under dark and anoxic conditions revealed that axenic S. marinoi is able to reduce intracellular nitrate to ammonium that is immediately excreted by the cells. When exposed to a light:dark cycle and oxic conditions, S. marinoi stored nitrate intracellularly in concentrations > 60 mmol L-1 both as free-living cells and associated to aggregates. Intracellular nitrate concentrations exceeded extracellular concentrations by three orders of magnitude. Intracellular nitrate was used up within 2-3 days after shifting diatom-bacteria aggregates to dark and anoxic conditions. Thirty-one percent of the diatom-derived nitrate was converted to nitrogen gas, indicating that a substantial fraction of the intracellular nitrate pool of S. marinoi becomes available to the aggregate-associated bacterial community. Only 5% of the intracellular nitrate was reduced to ammonium, while 59% was recovered as nitrite. Hence, aggregate-associated diatoms accumulate nitrate from the surrounding water and sustain complex nitrogen transformations, including loss of fixed nitrogen, in anoxic, pelagic microniches. Additionally, it may be expected that intracellular nitrate not converted before the aggregates have settled onto the seafloor could fuel benthic nitrogen transformations.

  4. Intracellular Nitrate of Marine Diatoms as a Driver of Anaerobic Nitrogen Cycling in Sinking Aggregates

    Science.gov (United States)

    Kamp, Anja; Stief, Peter; Bristow, Laura A.; Thamdrup, Bo; Glud, Ronnie N.

    2016-01-01

    Diatom-bacteria aggregates are key for the vertical transport of organic carbon in the ocean. Sinking aggregates also represent pelagic microniches with intensified microbial activity, oxygen depletion in the center, and anaerobic nitrogen cycling. Since some of the aggregate-forming diatom species store nitrate intracellularly, we explored the fate of intracellular nitrate and its availability for microbial metabolism within anoxic diatom-bacteria aggregates. The ubiquitous nitrate-storing diatom Skeletonema marinoi was studied as both axenic cultures and laboratory-produced diatom-bacteria aggregates. Stable 15N isotope incubations under dark and anoxic conditions revealed that axenic S. marinoi is able to reduce intracellular nitrate to ammonium that is immediately excreted by the cells. When exposed to a light:dark cycle and oxic conditions, S. marinoi stored nitrate intracellularly in concentrations >60 mmol L-1 both as free-living cells and associated to aggregates. Intracellular nitrate concentrations exceeded extracellular concentrations by three orders of magnitude. Intracellular nitrate was used up within 2–3 days after shifting diatom-bacteria aggregates to dark and anoxic conditions. Thirty-one percent of the diatom-derived nitrate was converted to nitrogen gas, indicating that a substantial fraction of the intracellular nitrate pool of S. marinoi becomes available to the aggregate-associated bacterial community. Only 5% of the intracellular nitrate was reduced to ammonium, while 59% was recovered as nitrite. Hence, aggregate-associated diatoms accumulate nitrate from the surrounding water and sustain complex nitrogen transformations, including loss of fixed nitrogen, in anoxic, pelagic microniches. Additionally, it may be expected that intracellular nitrate not converted before the aggregates have settled onto the seafloor could fuel benthic nitrogen transformations. PMID:27847498

  5. [Analysis of nitrogen distribution characters and their sources of the major input rivers of Three Gorges Reservoir].

    Science.gov (United States)

    Zheng, Bing-Hui; Cao, Cheng-Jin; Qin, Yan-Wen; Huang, Min-Sheng

    2008-01-01

    According to the survey conducted from Jan. 2004 to Dec. 2005, the seasonal characters of nitrogen in the water of input rivers of Three Gorges Reservoir (TGR) were discussed, and the forms and distributions of nitrogen among three major input rivers (Changjiang river, Jialingjiang river and Wujiang river) were studied. The results indicate that some primary hydrologic values of input rivers have seasonal characters, and they are in the danger range, which might bring algal bloom. The average contents per year of total nitrogen are 1.55-2.15 mg/L in the three monitor sections of input rivers of TGR, and Wulong monitor section is more severe than the others. The contents of total nitrogen in abundant water period are much higher than them in low water period, which displays the nonpoint source pollution has far-reaching influence upon total nitrogen. The total dissolved inorganic nitrogen (DIN) is the major form of total nitrogen and further nitrate nitrogen (NO3(-)-N) is dominant accounting for 70% or more of DIN. Ammoniacal nitrogen is the uppermost input form of nitrogen pollution of input rivers of TGR. Ammoniacal nitrogen was oxidated to nitroso-nitrogen, and then it was oxidated to nitrate nitrogen using up a lot of dissolved oxygen of water. Nitrate nitrogen sources include agricultural runoff, city pollution water, city runoff and slow-releasing from submersed soil, whenas nitrogen-ammonia (NH4(+)-N) origins are city pollution water, industrial pollution water, and a little source of living garbage and bilgewater.

  6. Reduction of Nitrogen Oxides Emissions from a Coal-Fired Boiler Unit

    Directory of Open Access Journals (Sweden)

    Zhuikov Andrey V.

    2016-01-01

    Full Text Available During combustion of fossil fuels a large amount of harmful substances are discharged into the atmospheres of cities by industrial heating boiler houses. The most harmful substances among them are nitrogen oxides. The paper presents one of the most effective technological solutions for suppressing nitrogen oxides; it is arrangement of circulation process with additional mounting of the nozzle directed into the bottom of the ash hopper. When brown high-moisture coals are burnt in the medium power boilers, generally fuel nitrogen oxides are produced. It is possible to reduce their production by two ways: lowering the temperature in the core of the torch or decreasing the excess-air factor in the boiler furnace. Proposed solution includes the arrangement of burning process with additional nozzle installed in the lower part of the ash hopper. Air supply from these nozzles creates vortex involving large unburned fuel particles in multiple circulations. Thereby time of their staying in the combustion zone is prolonging. The findings describe the results of the proposed solution; and recommendations for the use of this technological method are given for other boilers.

  7. Removal of nitrogen and phosphorous from domestic wastewater

    Directory of Open Access Journals (Sweden)

    Kulakov Artem

    2017-01-01

    Full Text Available This work is aimed at providing a deep cleaning from nitrogen and phosphorus at the requirements level for a small capacity waste water treatment plants with active sludge. The wastewater treatment technology includes: mechanical screen, anaerobic reactor, anoxic reactor, two aerobic reactors with floating media, aerobic reactor, clarifier, bioreactor, purification, filter, filter of tertiary treatment with the sorbent, ultraviolet disinfection facility. The sludge treatment includes aerobic stabilizer and facility of mechanical dewatering. The developed technology ensures deep purification of household waste waters from nitrogen and phosphorus. The degree of purification in the ammonium-ion reaches of 99.5%. Efficiency of total nitrogen removal (the sum of ammonium, nitrite and nitrate nitrogen is 85%. The efficiency of biological purification of phosphates is 97.8 percent that is achieved without the use of coagulant. Requirements are met in most cases.

  8. Eighth international congress on nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  9. Efficiency of nitrogen fertilizers for rice

    OpenAIRE

    Roger, Pierre-Armand; Grant, I.F.; Reddy, P.M.; Watanabe, I.

    1987-01-01

    The photosynthetic biomass that develops in the floodwater of wetland rice fields affects nitrogen dynamics in the ecosystem. This review summarizes available data on the nature, productivity, and composition of the photosynthetic aquatic biomass, and its major activities regarding the nitrogen cycle, i.e., nitrogen fixation by free living blue-green algae and #Azolla$, nitrogen trapping, nitrogen accumulation at the soil surface, its effect on nitrogen losses by ammonia volatilization, nitro...

  10. Nitrogen Chemistry in the Interstellar Medium

    Science.gov (United States)

    McGonagle, D.

    1995-01-01

    We have carried out radio observations for the interstellar molecules NO, NS, and HCCN in order to investigate the role of nitrogen in the chemistry of the interstellar medium (ISM). Abundances of these species and implications for chemistry models are discussed. In addition, we have conducted a spectral line survey towards the star forming region Orion(KL) over the frequency range 160-170 GHz, which revealed a large number of spectral features arising from such nitrogen-bearing molecules as NS, HNCO, HCCCN, CHCN, CHCHCN, and CHCHCN. The first detection of interstellar nitric oxide (NO) in the cold dark cloud L134N is reported, and we also confirm the subsequent detection towards TMC-1. The inferred NO fractional abundance relative to molecular hydrogen for L134N is f ~ 5 W 10 towards the position of peak SO emission in that cloud. The inferred fractional abundance for TMC-1 is f ~ 2 W 10 towards the position of peak NH emission. These fractional abundances are in good agreement with predictions of quiescent cloud ion-molecule chemistry. We estimate f(N)/f(NO) ~ 140, which suggests that the bulk of the gas-phase nitrogen in quiescent clouds is in the form of N , as the ion-molecule chemistry models suggest. The first detection of interstellar nitrogen sulfide (NS) in cold dark clouds is reported. Several components of the , J = 3/2 --> 1/2 and J = 5/2 --> 3/2 rotational transitions were observed towards TMC-1 and L134N. The inferred column density for TMC-1 is f ~ 8 W 10 towards the NH peak in that cloud, and in L134N is f ~ 6 W 10 towards the position of peak NH emission. We have found that NS emission is extended in both clouds. The inferred NS fractional abundances are significantly higher than those predicted by some recent gas-phase ion-molecule models. Our astronomical observations of NS have led to new laboratory spectroscopy which has resulted in more accurate NS transition frequencies, and a corresponding determination of the NS molecular constants to a

  11. Soil Microbial Communities and Gas Dynamics Contribute to Arbuscular Mycorrhizal Nitrogen Uptake and Transfer to Plants

    Science.gov (United States)

    Hestrin, R.; Harrison, M. J.; Lehmann, J.

    2016-12-01

    Arbuscular mycorrhizal fungi (AMF) associate with most terrestrial plants and influence ecosystem ecology and biogeochemistry. There is evidence that AMF play a role in soil nitrogen cycling, in part by taking up nitrogen and transferring it to plants. However, many aspects of this process are poorly understood, including the factors that control fungal access to nitrogen stored in soil organic matter. In this study, we used stable isotopes and root exclusion to track nitrogen movement from organic matter into AMF and host plants. AMF significantly increased total plant biomass and nitrogen content, but both AMF and other soil microbes seemed to compete with plants for nitrogen. Surprisingly, gaseous nitrogen species also contributed significantly to plant nitrogen content under alkaline soil conditions. Our current experiments investigate whether free-living microbial communities that have evolved under a soil nitrogen gradient influence AMF access to soil organic nitrogen and subsequent nitrogen transfer to plants. This research links interactions between plants, mycorrhizal symbionts, and free-living microbes with terrestrial carbon and nitrogen dynamics.

  12. Soil nitrogen availability in the open steppe with Stipa tenacissima

    Science.gov (United States)

    Novosadova, Irena; Damian Ruiz Sinoga, Jose; Záhora, Jaroslav

    2010-05-01

    functioning, particularly in Mediterranean areas, where nutrient availability, mainly nitrogen and phosphorous, represents a limiting factor (Sardans et al., 2005) together with water availability. Soil N availability has been found to affect plant water use efficiency (Sardans et al., 2008a). This strong link between N availability and water use efficiency makes particularly important the understanding of factors affecting soil N availability in Mediterranean ecosystems in view of the future predicted increasing drought in this area. Changes in the soil nitrogen availability in the open steppe with S. tenacissima were monitored over a two distinct period of time during the years 2008 and 2009 at a field site in semi-arid south-eastern Spain (Novosádová et al., 2010). The availability of ammonia-nitrogen and nitrate nitrogen was estimated in situ according to Binkley at Matson (1982) by the trapping of mineral N into the ion exchange resin inserted into special cover. The availability of soil ammonia-N as well as the availability of nitrate-N were in the 2008 year significantly influenced by the addition of different substrate (only 38% of control after the cellulose addition and 176% of control after the raw silk addition). In the following 2009 year was the N availability probably due to favorable soil moisture nearly the same in all experimental variants. The availability of ammonia-N was, in general, higher than the availability of nitrate-N, but the differences were less noticeable in 2008 year. It can be concluded, that the microbial competition for available nitrogen is very high and spatially and/or temporary significantly different.

  13. Nitrogen-Doped Graphitic Nanoribbons: Synthesis, Characterization and Transport

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Xiaoting [Massachusetts Institute of Technology (MIT); Dresselhaus, M [Massachusetts Institute of Technology (MIT); Cruz Silva, Eduardo [ORNL; Munoz-Sandoval, E [Instituto de Microelectronica de Madrid (CNM, CSIC); Sumpter, Bobby G [ORNL; Terrones Maldonado, Humberto [ORNL; Terrones Maldonado, Humberto [ORNL; Lopez, Florentino [IPICyT

    2013-01-01

    Nitrogen-doped graphitic nanoribbons (Nx-GNRs), synthesized by chemical vapor deposition (CVD) using pyrazine as a nitrogen precursor, are reported for the first time. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) reveal that the synthesized materials are formed by multi-layered corrugated graphitic nanoribbons (GNRs) which in most cases exhibit the formation of curved graphene edges (loops). This suggests that during growth, nitrogen atoms promote loop formation; undoped GNRs do not form loops at their edges. Transport measurements on individual pure carbon GNRs exhibit a linear I-V (current-voltage) behavior, whereas Nx-GNRs show reduced current responses following a semiconducting-like behavior, which becomes more prominent for high nitrogen concentrations. To better understand the experimental findings, electron density of states (DOS), quantum conductance for nitrogen doped zigzag and armchair single-layer GNRs are calculated for different N doping concentrations using Density Functional Theory (DFT) and non-equilibrium Green functions. These calculations confirm the crucial role of nitrogen atoms in the transport properties, confirming that the nonlinear I-V curves are due to the presence of nitrogen atoms within the Nx-GNRs lattice that act as scattering sites. These characteristic Nx-GNRs transport could be advantageous in the fabrication of electronic devices including sensors in which metal-like undoped GNRs are unsuitable.

  14. Plant densities and modulation of symbiotic nitrogen fixation in soybean

    Directory of Open Access Journals (Sweden)

    Marcos Javier de Luca

    2014-06-01

    Full Text Available Soybean nitrogen (N demands can be supplied to a large extent via biological nitrogen fixation, but the mechanisms of source/sink regulating photosynthesis/nitrogen fixation in high yielding cultivars and current crop management arrangements need to be investigated. We investigated the modulation of symbiotic nitrogen fixation in soybean [Glycine max (L. Merrill] at different plant densities. A field trial was performed in southern Brazil with six treatments, including non-inoculated controls without and with N-fertilizer, both at a density of 320,000 plants ha−1, and plants inoculated with Bradyrhizobium elkanii at four densities, ranging from 40,000 to 320,000 plants ha−1. Differences in nodulation, biomass production, N accumulation and partition were observed at stage R5, but not at stage V4, indicating that quantitative and qualitative factors (such as sunlight infrared/red ratio assume increasing importance during the later stages of plant growth. Decreases in density in the inoculated treatments stimulated photosynthesis and nitrogen fixation per plant. Similar yields were obtained at the different plant densities, with decreases only at the very low density level of 40,000 plants ha−1, which was also the only treatment to show differences in seed protein and oil contents. Results confirm a fine tuning of the mechanisms of source/sink, photosynthesis/nitrogen fixation under lower plant densities. Higher photosynthesis and nitrogen fixation rates are capable of sustaining increased plant growth.

  15. Nitrogen condensation in Titan's atmosphere under contemporary atmospheric composition

    Science.gov (United States)

    Tokano, Tetsuya

    2017-06-01

    Temperature profiles of Titan's atmosphere obtained by Cassini radio occultations approach the nitrogen condensation temperature curve at some places. This raises the question as to whether nitrogen, Titan's main atmospheric constituent, might condense in some seasons and areas contrary to previous perception. To address this question, possible areas and seasons of nitrogen condensation are searched for by a global climate model. The model is run under the present atmospheric pressure and composition but under various orbital configurations including the present one. Under the present orbital configuration the polar temperature at either pole becomes lowest around the northern autumnal equinox one season after aphelion. Liquid nitrogen clouds may appear in this season between 30 and 40 km altitude at least near the south pole, presumably embedded in icy methane clouds. Any falling nitrogen rain is likely to entirely evaporate before reaching the surface and thus does not affect the seasonal cycle of surface pressure. Seasonal nitrogen condensation is more frequent and intense when Saturn's orbital eccentricity is larger and hence the heliocentric distance at aphelion is larger. Nevertheless, orbital parameter variations alone are not capable of flooding the surface with liquid nitrogen or causing large fluctuations of the surface pressure.

  16. Incorporating nitrogen fixing cyanobacteria in the global biogeochemical model HAMOCC

    Science.gov (United States)

    Paulsen, Hanna; Ilyina, Tatiana; Six, Katharina

    2015-04-01

    Nitrogen fixation by marine diazotrophs plays a fundamental role in the oceanic nitrogen and carbon cycle as it provides a major source of 'new' nitrogen to the euphotic zone that supports biological carbon export and sequestration. Since most global biogeochemical models include nitrogen fixation only diagnostically, they are not able to capture its spatial pattern sufficiently. Here we present the incorporation of an explicit, dynamic representation of diazotrophic cyanobacteria and the corresponding nitrogen fixation in the global ocean biogeochemical model HAMOCC (Hamburg Ocean Carbon Cycle model), which is part of the Max Planck Institute for Meteorology Earth system model (MPI-ESM). The parameterization of the diazotrophic growth is thereby based on available knowledge about the cyanobacterium Trichodesmium spp., which is considered as the most significant pelagic nitrogen fixer. Evaluation against observations shows that the model successfully reproduces the main spatial distribution of cyanobacteria and nitrogen fixation, covering large parts of the tropical and subtropical oceans. Besides the role of cyanobacteria in marine biogeochemical cycles, their capacity to form extensive surface blooms induces a number of bio-physical feedback mechanisms in the Earth system. The processes driving these interactions, which are related to the alteration of heat absorption, surface albedo and momentum input by wind, are incorporated in the biogeochemical and physical model of the MPI-ESM in order to investigate their impacts on a global scale. First preliminary results will be shown.

  17. Additive Manufacturing Infrared Inspection

    Science.gov (United States)

    Gaddy, Darrell; Nettles, Mindy

    2015-01-01

    The Additive Manufacturing Infrared Inspection Task started the development of a real-time dimensional inspection technique and digital quality record for the additive manufacturing process using infrared camera imaging and processing techniques. This project will benefit additive manufacturing by providing real-time inspection of internal geometry that is not currently possible and reduce the time and cost of additive manufactured parts with automated real-time dimensional inspections which deletes post-production inspections.

  18. Evidence that northern pioneering pines with tuberculate mycorrhizae are unaffected by varying soil nitrogen levels.

    Science.gov (United States)

    Chapman, William Kenneth; Paul, Leslie

    2012-11-01

    Tuberculate mycorrhizae on Pinus contorta (lodgepole pine) have previously been shown to reduce acetylene, but an outstanding question has been to what degree these structures could meet the nitrogen requirements of the tree. We compared the growth, tissue nitrogen contents, and stable nitrogen isotope ratios of P. contorta growing in gravel pits to the same species growing on adjacent intact soil. Trees growing in severely nitrogen deficient gravel pits had virtually identical growth rates and tissue nitrogen contents to those growing on intact soil that had nitrogen levels typical for the area. δ(15)N values for trees in the gravel pits were substantially lower than δ(15)N values for trees on intact soil, and isotope ratios in vegetation were lower than the isotope ratios of the soil. The form of soil nitrogen in the gravel pits was almost exclusively nitrate, while ammonium predominated in the intact soil. Discrimination against (15)N during plant uptake of soil nitrate in the highly N-deficient soil should be weak or nonexistent. Therefore, the low δ(15)N in the gravel pit trees suggests that trees growing in gravel pits were using another nitrogen source in addition to the soil. Precipitation-borne nitrogen in the study area is extremely low. In conjunction with our other work, these findings strongly suggests that P. contorta and its microbial symbionts or associates fix nitrogen in sufficient amounts to sustain vigorous tree growth on the most nitrogen-deficient soils.

  19. Nitrogen system for the SSC

    International Nuclear Information System (INIS)

    McAshan, M.; Thirumaleshwar, M.; Abramovich, S.; Ganni, V.

    1992-10-01

    The Superconducting Super Collider consists of two parallel magnet rings, each 87,120 m in circumference, constructed in a tunnel 25 m to 74 m below ground level. They are operated at a controlled low helium temperature in order to maintain the magnet windings in the superconducting state. To obtain this condition, the magnet cryostat is designed with a high-quality insulation obtained by a high vacuum chamber, multilayer insulation, and thermal shields at nominal temperatures of 84 K and 20 K. Thermal radiation and the conduction heat load through the supports are intercepted and absorbed by the 84-K shield. Liquid nitrogen provides the refrigeration for these loads. The 84-K shield is anchored to two 63.5-mm stainless-steel tubes. One of the tubes, the ''liquid line,'' serves as a conduit in the distribution system of liquid nitrogen. The other tube, the ''vapor line,'' is used to collect the nitrogen vapor generated in the cooling process and to supply this vapor to,the helium refrigerators for precooling. The vapor line may also be used as a continuous cooler by injecting controlled amounts of liquid nitrogen. The nitrogen system consists of nitrogen supplies; ten nitrogen dewars for the collider and two for the High Energy Booster located on the ground at the main shaft entrances; liquid and vapor transfer lines through the shaft to connect the surface and the tunnel systems; and transfer lines to bypass warm equipment sections of the collider. The nitrogen system is expected to operate at steady state condition except for cooldown, warmup, and system repair, for which transients are expected. During normal operation and standby modes of the collider, temperature, pressure, and mass flow are expected to be constant in all circuits of the nitrogen system. The conceptual design requirements for various flow schemes and the engineering considerations are presented in this report

  20. [Food additives and healthiness].

    Science.gov (United States)

    Heinonen, Marina

    2014-01-01

    Additives are used for improving food structure or preventing its spoilage, for example. Many substances used as additives are also naturally present in food. The safety of additives is evaluated according to commonly agreed principles. If high concentrations of an additive cause adverse health effects for humans, a limit of acceptable daily intake (ADI) is set for it. An additive is a risk only when ADI is exceeded. The healthiness of food is measured on the basis of nutrient density and scientifically proven effects.

  1. Nitrogen metabolism meets phytopathology.

    Science.gov (United States)

    Fagard, Mathilde; Launay, Alban; Clément, Gilles; Courtial, Julia; Dellagi, Alia; Farjad, Mahsa; Krapp, Anne; Soulié, Marie-Christine; Masclaux-Daubresse, Céline

    2014-10-01

    Nitrogen (N) is essential for life and is a major limiting factor of plant growth. Because soils frequently lack sufficient N, large quantities of inorganic N fertilizers are added to soils for crop production. However, nitrate, urea, and ammonium are a major source of global pollution, because much of the N that is not taken up by plants enters streams, groundwater, and lakes, where it affects algal production and causes an imbalance in aquatic food webs. Many agronomical data indicate that the higher use of N fertilizers during the green revolution had an impact on the incidence of crop diseases. In contrast, examples in which a decrease in N fertilization increases disease severity are also reported, indicating that there is a complex relationship linking N uptake and metabolism and the disease infection processes. Thus, although it is clear that N availability affects disease, the underlying mechanisms remain unclear. The aim of this review is to describe current knowledge of the mechanisms that link plant N status to the plant's response to pathogen infection and to the virulence and nutritional status of phytopathogens. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Energy, industry and nitrogen: strategies for decreasing reactive nitrogen emissions.

    Science.gov (United States)

    Moomaw, William R

    2002-03-01

    Nitrogen oxides are released during atmospheric combustion of fossil fuels and biomass, and during the production of certain chemicals and products. They can react with natural or man-made volatile organic compounds to produce smog, or else can be further oxidized to produce particulate haze, or acid rain that can eutrophy land and water. The reactive nitrogen that begins in the energy sector thus cascades through the atmosphere, the hydrosphere and soils before being eventually partially denitrifed to the global warming and stratospheric ozone-depleting gas nitrous oxide or molecular nitrogen. This paper will suggest how an economic analysis of the nitrogen cycle can identify the most cost-effective places to intervene. Nitrogen oxides released during fossil-fuel combustion in vehicles, power plants and heating boilers can either be controlled by add-on emission control technology, or can be eliminated by many of the same technical options that lead to carbon dioxide reduction. These integrated strategies also address sustainability, economic development and national security issues. Similarly in industrial production, it is more effective to focus on redesigning industrial processes rather than on nitrogen oxide pollution elimination from the current system. This paper will suggest which strategies might be utilized to address multiple benefits rather than focusing on single pollutants.

  3. Quantifying benthic nitrogen fluxes in Puget Sound, Washington: a review of available data

    Science.gov (United States)

    Sheibley, Richard W.; Paulson, Anthony J.

    2014-01-01

    Understanding benthic fluxes is important for understanding the fate of materials that settle to the Puget Sound, Washington, seafloor, as well as the impact these fluxes have on the chemical composition and biogeochemical cycles of marine waters. Existing approaches used to measure benthic nitrogen flux in Puget Sound and elsewhere were reviewed and summarized, and factors for considering each approach were evaluated. Factors for selecting an appropriate approach for gathering information about benthic flux include: availability of resources, objectives of projects, and determination of which processes each approach measures. An extensive search of literature was undertaken to summarize known benthic nitrogen fluxes in Puget Sound. A total of 138 individual flux chamber measurements and 38 sets of diffusive fluxes were compiled for this study. Of the diffusive fluxes, 35 new datasets were located, and new flux calculations are presented in this report. About 65 new diffusive flux calculations are provided across all nitrogen species (nitrate, NO3-; nitrite, NO2-; ammonium, NH4+). Data analysis of this newly compiled benthic flux dataset showed that fluxes beneath deep (greater than 50 meters) water tended to be lower than those beneath shallow (less than 50 meters) water. Additionally, variability in flux at the shallow depths was greater, possibly indicating a more dynamic interaction between the benthic and pelagic environments. The overall range of bottom temperatures from studies in the Puget Sound area were small (5–16 degrees Celsius), and only NH4+ flux showed any pattern with temperature. For NH4+, flux values and variability increased at greater than about 12 degrees Celsius. Collection of additional study site metadata about environmental factors (bottom temperature, depth, sediment porosity, sediment type, and sediment organic matter) will help with development of a broader regional understanding benthic nitrogen flux in the Puget Sound.

  4. Additives in yoghurt production

    Directory of Open Access Journals (Sweden)

    Milna Tudor

    2008-02-01

    Full Text Available In yoghurt production, mainly because of sensory characteristics, different types of additives are used. Each group, and also each substance from the same group has different characteristics and properties. For that reason, for improvement of yoghurt sensory characteristics apart from addition selection, the quantity of the additive is very important. The same substance added in optimal amount improves yoghurt sensory attributes, but too small or too big addition can reduce yoghurt sensory attributes. In this paper, characteristics and properties of mostly used additives in yoghurt production are described; skimmed milk powder, whey powder, concentrated whey powder, sugars and artificial sweeteners, fruits, stabilizers, casein powder, inulin and vitamins. Also the impact of each additive on sensory and physical properties of yoghurt, syneresis and viscosity, are described, depending on used amount added in yoghurt production.

  5. Buckminsterfullerenes: a non-metal system for nitrogen fixation.

    Science.gov (United States)

    Nishibayashi, Yoshiaki; Saito, Makoto; Uemura, Sakae; Takekuma, Shin-Ichi; Takekuma, Hideko; Yoshida, Zen-Ichi

    2004-03-18

    In all nitrogen-fixation processes known so far--including the industrial Haber-Bosch process, biological fixation by nitrogenase enzymes and previously described homogeneous synthetic systems--the direct transformation of the stable, inert dinitrogen molecule (N2) into ammonia (NH3) relies on the powerful redox properties of metals. Here we show that nitrogen fixation can also be achieved by using a non-metallic buckminsterfullerene (C60) molecule, in the form of a water-soluble C60:gamma-cyclodextrin (1:2) complex, and light under nitrogen at atmospheric pressure. This metal-free system efficiently fixes nitrogen under mild conditions by making use of the redox properties of the fullerene derivative.

  6. Kinetics of nitrogen removal processes in constructed wetlands

    Science.gov (United States)

    Gajewska, Magdalena; Skrzypiec, Katarzyna

    2018-01-01

    The aim of this paper is to present a state-of-the-art review of the kinetics of nitrogen removal in constructed wetlands. Biological processes of nitrogen removal from wastewater can be described using equations and kinetic models. Hence, these kinetic models which have been developed and evaluated allow for predicting the removal of nitrogen in treatment wetlands. One of the most important, first order removal model, which is still applied, was analysed and its rate coefficients and factors were compared. This study also demonstrates the validity of Monod and multiple Monod kinetics, commonly seen today. Finally, a computational example of the reaction kinetics of nitrogen removal was also included in the study.

  7. Kinetics of nitrogen removal processes in constructed wetlands

    Directory of Open Access Journals (Sweden)

    Gajewska Magdalena

    2018-01-01

    Full Text Available The aim of this paper is to present a state-of-the-art review of the kinetics of nitrogen removal in constructed wetlands. Biological processes of nitrogen removal from wastewater can be described using equations and kinetic models. Hence, these kinetic models which have been developed and evaluated allow for predicting the removal of nitrogen in treatment wetlands. One of the most important, first order removal model, which is still applied, was analysed and its rate coefficients and factors were compared. This study also demonstrates the validity of Monod and multiple Monod kinetics, commonly seen today. Finally, a computational example of the reaction kinetics of nitrogen removal was also included in the study.

  8. Nitrogen studies for achieving the whole-year harvest

    International Nuclear Information System (INIS)

    Boven, G.D.; Danso, K.A.

    1987-01-01

    The IAEA activity in solving the problems related to recovery of productivity of soils subjected to erosion in tropical regions using nitrogen-fixator plants which include pasture bean crops and trees, is considered. The IAEA activity covers development of appropriate methods of changing fixed nitrogen in perennial plants, determination of practical ways of increasing nitrogen fixation and development of reliable and high-productivity systems of bean-herb pastures. The main attention is paid to methods of farming and selection. Favourable effect of forest planting on recovery and preservation of soil productivity and important role of isotopic and nuclear methods (using 15 N) in care for trees and nitrogen fixation improvement are underlined

  9. Behavior and Release of Nitrogen at Mines and Quarries in Nordic Conditions

    Science.gov (United States)

    Karlsson, Teemu; Neitola, Raisa; Jermakka, Johannes; Merta, Elina; Mroueh, Ulla-Maija

    2015-04-01

    The increased extraction of mineral resources and mining activities creates added pressure on the environmental issues and a proper water management in mining areas in Finland. Among others, nitrogen compounds released from explosives or from mining processes can have a detrimental effect on the environment. Thus, this project aimed at comprehensive understanding on the nitrogen issue in the extractive industry. The project collected essential data on nitrogen compounds present in the environments of mines and quarries, and generated better understanding of the discharge and behaviour of nitrogen compounds in mining areas. The sources and balances of explosives-originated nitrogen compounds at mines and quarries of different sizes were investigated and compared. Additionally, the focus was in 'nitrogen smudging' problem of waste rocks and the intensity, as well as evolution and chemical characteristics of their nitrogen contamination. According to the results, the total load of potential nitrogen to the environment depends on the scale and type of the activity as well as the type of explosives used. The main emission sources of nitrogen are process and dewatering waters. A lysimeter study showed that the explosives originated nitrogen content of left over stones from natural stone quarrying is relatively low and ca. half of the nitrogen is leached within the first weeks after detonation. The "nitrogen smudging" of natural stone quarrying left over stones is relatively low to begin with and enhanced by the rapid flushing by rainwater, thus the residues of explosives should not be considered to prevent the utilization of otherwise mineralogically inert waste rocks of good technical quality. The overall nitrogen management should take into account the background concentrations and sensitivity of the local ecosystem. The research project "Solution for Control of Nitrogen Discharges at Mines and Quarries, (MINIMAN)" was realized during years 2012-2014 as a cooperative

  10. Chitin: 'Forgotten' Source of Nitrogen: From Modern Chitin to Thermally Mature Kerogen: Lessons from Nitrogen Isotope Ratios

    Science.gov (United States)

    Schimmelmann, A.; Wintsch, R.P.; Lewan, M.D.; DeNiro, M.J.

    1998-01-01

    Chitinous biomass represents a major pool of organic nitrogen in living biota and is likely to have contributed some of the fossil organic nitrogen in kerogen. We review the nitrogen isotope biogeochemistry of chitin and present preliminary results suggesting interaction between kerogen and ammonium during thermal maturation. Modern arthropod chitin may shift its nitrogen isotope ratio by a few per mil depending on the chemical method of chitin preparation, mostly because N-containing non-amino-sugar components in chemically complex chitin cannot be removed quantitatively. Acid hydrolysis of chemically complex chitin and subsequent ion-chromatographic purification of the "deacetylated chitin-monomer" D-glucosamine (in hydrochloride form) provides a chemically well-defined, pure amino-sugar substrate for reproducible, high-precision determination of ??15N values in chitin. ??15N values of chitin exhibited a variability of about one per mil within an individual's exoskeleton. The nitrogen isotope ratio differed between old and new exoskeletons by up to 4 per mil. A strong dietary influence on the ??15N value of chitin is indicated by the observation of increasing ??15N values of chitin from marine crustaceans with increasing trophic level. Partial biodegradation of exoskeletons does not significantly influence ??15N values of remaining, chemically preserved amino sugar in chitin. Diagenesis and increasing thermal maturity of sedimentary organic matter, including chitin-derived nitrogen-rich moieties, result in humic compounds much different from chitin and may significantly change bulk ??15N values. Hydrous pyrolysis of immature source rocks at 330??C in contact with 15N-enriched NH4Cl, under conditions of artificial oil generation, demonstrates the abiogenic incorporation of inorganic nitrogen into carbon-bound nitrogen in kerogen. Not all organic nitrogen in natural, thermally mature kerogen is therefore necessarily derived from original organic matter, but may

  11. Ecological occurrence of Gluconacetobacter diazotrophicus and nitrogen-fixing Acetobacteraceae members: their possible role in plant growth promotion.

    Science.gov (United States)

    Saravanan, V S; Madhaiyan, M; Osborne, Jabez; Thangaraju, M; Sa, T M

    2008-01-01

    Gluconacetobacter diazotrophicus has a long-standing history of bacterial-plant interrelationship as a symbiotic endophyte capable of fixing atmospheric nitrogen. In low nitrogen fertilized sugarcane fields it plays a significant role and its occurrence was realised in most of the sugarcane growing countries. In this mini review, the association of G. diazotrophicus with sugarcane, other crop plants and with various hosts is discussed. The factors affecting survival in the rhizosphere and the putative soil mode of transmission are emphasized. In addition, other N(2)-fixing Acetobacteraceae members, including Gluconacetobacter azotocaptans, Gluconacetobacter johannae and Swaminathania salitolerans, occurring in coffee, corn and rice plants are also covered. Lastly, the plant-growth-promoting traits identified in this group of bacteria, including N(2) fixation, phytohormone synthesis, P and Zn solubilization and biocontrol, are analysed.

  12. Quantifying atmospheric nitrogen outflow from the Front Range of Colorado

    Science.gov (United States)

    Neuman, J. A.; Eilerman, S. J.; Brock, C. A.; Brown, S. S.; Dube, W. P.; Herndon, S. C.; Holloway, J. S.; Nowak, J. B.; Roscioli, J. R.; Ryerson, T. B.; Sjostedt, S. J.; Thompson, C. R.; Trainer, M.; Veres, P. R.; Wild, R. J.

    2015-12-01

    Reactive nitrogen emitted to the atmosphere from urban, industrial, and agricultural sources can be transported and deposited far from the source regions, affecting vegetation, soils, and water of sensitive ecosystems. Mitigation of atmospheric nitrogen deposition requires emissions characterization and quantification. Ammonia (NH3), a full suite of gas-phase oxidized nitrogen compounds, and particulate matter were measured from an aircraft that flew downwind from concentrated animal feeding operations, oil and gas extraction facilities, and urban areas along the Colorado Front Range in March and April 2015, as part of the Shale Oil and Natural Gas Nexus (SONGNEX) field study. Additionally, NH3 measurements from a fully instrumented aircraft that flew over the same region in July and August 2014 as part of the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) are used to examine atmospheric nitrogen emission and transport. Cross-wind plume transects and altitude profiles were performed over the source regions and 60-240 km downwind. Plumes were transported in the boundary layer with large NH3 mixing ratios (typically 20-100 ppbv) and were tens of km wide. The NH3 in these plumes provided an atmospheric nitrogen burden greater than 0.2 kg N/ha. Nitrogen oxides and their oxidation products and particulate matter were also enhanced in the plumes, but with concentrations substantially less than NH3. With efficient transport followed by wet deposition, these plumes have the potential to provide a large nitrogen input to the neighboring Rocky Mountain National Park, where nitrogen deposition currently exceeds the ecological critical load of 1.5 kg N/ha/yr.

  13. Nitrogen balance during growth of cauliflower

    NARCIS (Netherlands)

    Everaarts, A.P.

    2000-01-01

    The potential for loss of nitrogen to the environment during growth of cauliflower was investigated. A comparison was made between cauliflower growth and nitrogen uptake without, and with, nitrogen application of the recommended amount (=225 kg ha-1 minus mineral nitrogen in the soil layer 0–60 cm,

  14. Managing Nitrogen in the anthropocene: integrating social and ecological science

    Science.gov (United States)

    Zhang, X.; Mauzerall, D. L.; Davidson, E. A.; Kanter, D.; Cai, R.; Searchinger, T.

    2014-12-01

    . Overall, our research suggests that it is critical to include social and economic processes when studying perturbations of the global nitrogen cycle and crafting environmental and food security policy. Better collaboration across disciplines is essential to improve nitrogen management in the anthropocene.

  15. Maximum-likelihood estimation in linkage heterogeneity models including additional information via the EM algorithm

    NARCIS (Netherlands)

    Houwing-Duistermaat, J. J.; Sandkuijl, L. A.; Bergen, A. A.; van Houwelingen, H. C.

    1995-01-01

    In linkage analysis, estimated recombination fractions between a disease gene and several markers are used to assign the disease gene to a particular chromosome region. For rare diseases, locus heterogeneity leads to different recombination fractions in different families, and a set of pedigrees can

  16. Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species

    Science.gov (United States)

    Vermeulen, Jaap J.; Liew, Thor-Seng; Schilthuizen, Menno

    2015-01-01

    Abstract We present reviews of the Sabah (Malaysia, on the island of Borneo) species of the following problematical genera of land snails (Mollusca, Gastropoda): Acmella and Anaglyphula (Caenogastropoda: Assimineidae); Ditropopsis (Caenogastropoda: Cyclophoridae); Microcystina (Pulmonata: Ariophantidae); Philalanka and Thysanota (Pulmonata: Endodontidae); Kaliella, Rahula, (Pulmonata: Euconulidae); Trochomorpha and Geotrochus (Pulmonata: Trochomorphidae). Next to this, we describe new species in previously revised genera, such as Diplommatina (Diplommatinidae); Georissa (Hydrocenidae); as well as some new species of genera not revised previously, such as Japonia (Cyclophoridae); Durgella and Dyakia (Ariophantidae); Amphidromus, and Trachia (Camaenidae); Paralaoma (Punctidae); Curvella (Subulinidae). All descriptions are based on the morphology of the shells. We distinguish the following 48 new species: Acmella cyrtoglyphe, Acmella umbilicata, Acmella ovoidea, Acmella nana, Acmella subcancellata, Acmella striata, and Anaglyphula sauroderma (Assimineidae); Ditropopsis davisoni, Ditropopsis trachychilus, Ditropopsis constricta, Ditropopsis tyloacron, Ditropopsis cincta, and Japonia anceps (Cyclophoridae); Diplommatina bidentata and Diplommatina tylocheilos (Diplommatinidae); Georissa leucococca and Georissa nephrostoma (Hydrocenidae); Durgella densestriata, Dyakia chlorosoma, Microcystina microrhynchus, Microcystina callifera, Microcystina striatula, Microcystina planiuscula, and Microcystina physotrochus (Ariophantidae); Amphidromus psephos and Trachia serpentinitica (Camaenidae); Philalanka tambunanensis, Philalanka obscura, Philalanka anomphala, Philalanka rugulosa, and Philalanka malimgunung (Endodontidae); Kaliella eurytrochus, Kaliella sublaxa, Kaliella phacomorpha, Kaliella punctata, Kaliella microsoma, Rahula delopleura, (Euconulidae); Paralaoma angusta (Punctidae); Curvella hadrotes (Subulinidae); Trochomorpha trachus, Trochomorpha haptoderma, Trochomorpha thelecoryphe, Geotrochus oedobasis, Geotrochus spilokeiria, Geotrochus scolops, Geotrochus kitteli, Geotrochus subscalaris, and Geotrochus meristorhachis (Trochomorphidae). PMID:26692803

  17. Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species.

    Science.gov (United States)

    Vermeulen, Jaap J; Liew, Thor-Seng; Schilthuizen, Menno

    2015-01-01

    We present reviews of the Sabah (Malaysia, on the island of Borneo) species of the following problematical genera of land snails (Mollusca, Gastropoda): Acmella and Anaglyphula (Caenogastropoda: Assimineidae); Ditropopsis (Caenogastropoda: Cyclophoridae); Microcystina (Pulmonata: Ariophantidae); Philalanka and Thysanota (Pulmonata: Endodontidae); Kaliella, Rahula, (Pulmonata: Euconulidae); Trochomorpha and Geotrochus (Pulmonata: Trochomorphidae). Next to this, we describe new species in previously revised genera, such as Diplommatina (Diplommatinidae); Georissa (Hydrocenidae); as well as some new species of genera not revised previously, such as Japonia (Cyclophoridae); Durgella and Dyakia (Ariophantidae); Amphidromus, and Trachia (Camaenidae); Paralaoma (Punctidae); Curvella (Subulinidae). All descriptions are based on the morphology of the shells. We distinguish the following 48 new species: Acmella cyrtoglyphe, Acmella umbilicata, Acmella ovoidea, Acmella nana, Acmella subcancellata, Acmella striata, and Anaglyphula sauroderma (Assimineidae); Ditropopsis davisoni, Ditropopsis trachychilus, Ditropopsis constricta, Ditropopsis tyloacron, Ditropopsis cincta, and Japonia anceps (Cyclophoridae); Diplommatina bidentata and Diplommatina tylocheilos (Diplommatinidae); Georissa leucococca and Georissa nephrostoma (Hydrocenidae); Durgella densestriata, Dyakia chlorosoma, Microcystina microrhynchus, Microcystina callifera, Microcystina striatula, Microcystina planiuscula, and Microcystina physotrochus (Ariophantidae); Amphidromus psephos and Trachia serpentinitica (Camaenidae); Philalanka tambunanensis, Philalanka obscura, Philalanka anomphala, Philalanka rugulosa, and Philalanka malimgunung (Endodontidae); Kaliella eurytrochus, Kaliella sublaxa, Kaliella phacomorpha, Kaliella punctata, Kaliella microsoma, Rahula delopleura, (Euconulidae); Paralaoma angusta (Punctidae); Curvella hadrotes (Subulinidae); Trochomorpha trachus, Trochomorpha haptoderma, Trochomorpha thelecoryphe, Geotrochus oedobasis, Geotrochus spilokeiria, Geotrochus scolops, Geotrochus kitteli, Geotrochus subscalaris, and Geotrochus meristorhachis (Trochomorphidae).

  18. Food Additives and Hyperkinesis: A Controlled Double-Blind Experiment. (Includes NIE Staff Critique).

    Science.gov (United States)

    Conners, C. Keith; And Others

    Fifteen hyperkinetic children (6-12 years old) were involved in a pilot study to test B. Feingold's hypothesis that hyperkinesis may be caused by artificial flavors and colors in food. Prior to treatment, parents and teachers completed bi-weekly questionnaires regarding each Ss' behavior both on medication (pretreatment period) and when medication…

  19. Voluntary Consensus Organization Standards for Nondestructive Evaluation of Aerospace Materials (including Additive Manufactured Parts)

    Data.gov (United States)

    National Aeronautics and Space Administration — This NASA-industry effort accomplishes the following:1) Lead collaboration between NASA Centers, other government agencies, industry, academia, and voluntary census...

  20. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Science.gov (United States)

    2010-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b Protection of Environment..., acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals... oxygen. (d) For approval, a State plan shall include emission limits for nitrogen oxides at least as...

  1. The Effects of Different Nitrogen Sources on Yield and Yield Components of Sweet Corn (Zea mays L. saccharata

    Directory of Open Access Journals (Sweden)

    ali mojab ghasroddashti

    2017-09-01

    Full Text Available Introduction Sweet corn (Zea mays L. saccharata is one of the tropical cereals of graminae which is cultivated in order to use for ear. Nitrogen is one of the most important nutrients and key factors to achieve desirable yield. Fertilizers play a major role in crop productivity. However, nowadays, excessive use of fertilizers have been found to have a negative impact on yield and environment. Introducing new management methods based on nitrogen and water use efficiency showed some improvements in the quality and quantity of crop production in association with the health of the community. In fact, soil organic matter content should be maintained in the appropriate level to improve fertility. Using municipal solid waste compost and poultry manure are appropriate solutions. They can increase soil organic matter, modify physicochemical properties and improve crop production. Moreover, they are able to solve problems caused by the accumulation of municipal solid waste compost and poultry manure. Material and Methods In order to investigate the impact of different sources of nitrogen on yield and yield components of sweet corn, a field experiment was conducted as a randomized complete block design with three replications in Marvdasht in 2013. Treatments included different resources of fertilizer: 200 kg.ha-1 net nitrogen (T1, 300 kg.ha-1 net nitrogen (T2, 8 ton.ha-1 poultry manure (T3, 24 ton.ha-1 municipal solid waste compost (T4, 150 kg net nitrogen + 2 ton municipal solid waste compost (T5, 100 kg net nitrogen + 4 ton poultry manure (T6, 150 kg net nitrogen + 6 ton municipal solid waste compost (T7, 100 kg.ha-1 net nitrogen + 12 ton municipal solid waste compost (T8 and fertilizer free (control (T9. At the time of crop maturity, two square meters from middle of each plot were harvested to measure yield and yield components. Statistical analysis was performed using the SAS statistical software. Least significant difference (LSD test at the five

  2. What Is the Geometry at Trigonal Nitrogen?

    Science.gov (United States)

    Sudlow, K. P.; Woolf, A. A.

    1998-01-01

    Organic texts invariably depict aliphatic amines as pyramidal but anilines as planar presumably because of contributions from resonance forms with double bonds from carbon to nitrogen. Other evidence relies on comparisons made from aqueous basicities and dipole moments. Subsequent developments using data from gas-phase acidities, computational modeling and X-ray diffraction contradict these old premises. Ab intio calculations pyramidal anilines to be more stable than planar in the gas phase. Single crystal structures show both planar and pyramidal anilines exist. The latter, including aniline itself and halo or methyl substituted anilines, have C-N lengths near single bonds. the former contain nitro-substituents which help delocalize the nitrogen lone pair density to produce C-N bond orders between 1.5 and 2. Planarity is also induced by attaching very electronegative groups directly to nitrogen as well as by sufficient intermolecular hydrogen bonding between amino and nitro groups to overcome energy differences between planar and pyramidal forms. VSEPR theory must be applied with discretion!

  3. Nitrogen induced modifications of MANOS memory properties

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaou, N., E-mail: n.nikolaou@inn.demokritos.gr [Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 153 10 Athens (Greece); Department of Physics, University of Patras, 265 04 Patras (Greece); Ioannou-Sougleridis, V.; Dimitrakis, P.; Normand, P. [Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 153 10 Athens (Greece); Skarlatos, D. [Department of Physics, University of Patras, 265 04 Patras (Greece); Giannakopoulos, K. [Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 153 10 Athens (Greece); Ladas, S. [Department of Chemical Engineering, University of Patras, 265 04 Patras (Greece); Pecassou, B.; BenAssayag, G. [CEMES-CNRS, Toulouse (France); Kukli, K. [Department of Chemistry, University of Helsinki, FI-00014 Helsinki (Finland); Institute of Physics, University of Tartu, Ravila 14c, EE-50411 Tartu (Estonia); Niinistö, J.; Rit