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Sample records for limits carbon availability

  1. Biomass of active microorganisms is not limited only by available carbon in the rhizosphere

    Science.gov (United States)

    Gilmullina, Aliia

    2017-04-01

    Microbial activity is generally limited by carbon (C) availability. The easily available substrate release by roots creates so called "hotspots" in the rhizosphere that drives microbial activity removing C limitation. We simulated a gradient of root exudates by glucose addition at different concentrations to stimulate the activation of microbial biomass (MB). Glucose was added at the rates lower than MB (5, 10, 25 and 50%) and at the rates similar or higher than MB (100, 150, 200, 250, 300 and 400%). During incubation CO2 efflux was measured by conductometry, the size of active MB and specific growth rate were estimated by substrate-induced growth response method. We tested a hypothesis that glucose addition exceeding 100% MB is able to activate major fraction of soil microbial community. Addition of glucose at concentrations higher than 5% decreased specific growth rate, demonstrating the shift of microbial community from r-strategy to K-strategy. The percentage of active MB grew up by the increase of glucose concentration. The treatment with glucose at 100% presented a dramatic shift in the activation of MB up to 14%. Contrary to our hypothesis, further increase in glucose rate caused moderate stimulation of active MB up to 22% of total MB. Furthermore, glucose addition above 200% did not increase the fraction of active biomass indicating glucose oversaturation and possible limitation by other nutrients. The results suggest that despite the fact that C is the most important limitation factor, limitless C supply is not able to activate MB up to 100%. Thus, if the rhizosphere is limited by nutrients, the fraction of active biomass remains at low level despite an excess of available C.

  2. Growth limitation of three Arctic sea-ice algae species: effects of salinitty, pH and inorganic carbon availability

    DEFF Research Database (Denmark)

    Søgaard, Dorte Haubjerg; Hansen, Per Juel; Rysgaard, Søren

    2011-01-01

    The effect of salinity, pH, and dissolved inorganic carbon (TCO(2)) on growth and survival of three Arctic sea ice algal species, two diatoms (Fragilariopsis nana and Fragilariopsis sp.), and one species of chlorophyte (Chlamydomonas sp.) was assessed in controlled laboratory experiments. Our res...

  3. Moisture availability limits subalpine tree establishment.

    Science.gov (United States)

    Andrus, Robert A; Harvey, Brian J; Rodman, Kyle C; Hart, Sarah J; Veblen, Thomas T

    2018-03-01

    In the absence of broad-scale disturbance, many temperate coniferous forests experience successful seedling establishment only when abundant seed production coincides with favorable climate. Identifying the frequency of past establishment events and the climate conditions favorable for seedling establishment is essential to understanding how climate warming could affect the frequency of future tree establishment events and therefore future forest composition or even persistence of a forest cover. In the southern Rocky Mountains, USA, research on the sensitivity of establishment of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa)-two widely distributed, co-occurring conifers in North America-to climate variability has focused on the alpine treeline ecotone, leaving uncertainty about the sensitivity of these species across much of their elevation distribution. We compared annual germination dates for >450 Engelmann spruce and >500 subalpine fir seedlings collected across a complex topographic-moisture gradient to climate variability in the Colorado Front Range. We found that Engelmann spruce and subalpine fir established episodically with strong synchrony in establishment events across the study area. Broad-scale establishment events occurred in years of high soil moisture availability, which were characterized by above-average snowpack and/or cool and wet summer climatic conditions. In the recent half of the study period (1975-2010), a decrease in the number of fir and spruce establishment events across their distribution coincided with declining snowpack and a multi-decadal trend of rising summer temperature and increasing moisture deficits. Counter to expected and observed increases in tree establishment with climate warming in maritime subalpine forests, our results show that recruitment declines will likely occur across the core of moisture-limited subalpine tree ranges as warming drives increased moisture deficits. © 2018 by the

  4. Inorganic carbon availability in benthic diatom communities: photosynthesis and migration.

    Science.gov (United States)

    Marques da Silva, Jorge; Cruz, Sónia; Cartaxana, Paulo

    2017-09-05

    Diatom-dominated microphytobenthos (MPB) is the main primary producer of many intertidal and shallow subtidal environments, being therefore of critical importance to estuarine and coastal food webs. Owing to tidal cycles, intertidal MPB diatoms are subjected to environmental conditions far more variable than the ones experienced by pelagic diatoms (e.g. light, temperature, salinity, desiccation and nutrient availability). Nevertheless, benthic diatoms evolved adaptation mechanisms to these harsh conditions, including the capacity to move within steep physical and chemical gradients, allowing them to perform photosynthesis efficiently. In this contribution, we will review present knowledge on the effects of dissolved inorganic carbon (DIC) availability on photosynthesis and productivity of diatom-dominated MPB. We present evidence of carbon limitation of photosynthesis in benthic diatom mats and highly productive MPB natural communities. Furthermore, we hypothesize that active vertical migration of epipelic motile diatoms could overcome local depletion of DIC in the photic layer, providing the cells alternately with light and inorganic carbon supply. The few available longer-term experiments on the effects of inorganic carbon enrichment on the productivity of diatom-dominated MPB have yielded inconsistent results. Therefore, further studies are needed to properly assess the response of MPB communities to increased CO 2 and ocean acidification related to climate change.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'. © 2017 The Author(s).

  5. Limits on carbon sequestration in arid blue carbon ecosystems.

    Science.gov (United States)

    Schile, Lisa M; Kauffman, J Boone; Crooks, Stephen; Fourqurean, James W; Glavan, Jane; Megonigal, J Patrick

    2017-04-01

    Coastal ecosystems produce and sequester significant amounts of carbon ("blue carbon"), which has been well documented in humid and semi-humid regions of temperate and tropical climates but less so in arid regions where mangroves, marshes, and seagrasses exist near the limit of their tolerance for extreme temperature and salinity. To better understand these unique systems, we measured whole-ecosystem carbon stocks in 58 sites across the United Arab Emirates (UAE) in natural and planted mangroves, salt marshes, seagrass beds, microbial mats, and coastal sabkha (inter- and supratidal unvegetated salt flats). Natural mangroves held significantly more carbon in above- and belowground biomass than other vegetated ecosystems. Planted mangrove carbon stocks increased with age, but there were large differences for sites of similar age. Soil carbon varied widely across sites (2-367 Mg C/ha), with ecosystem averages that ranged from 49 to 156 Mg C/ha. For the first time, microbial mats were documented to contain soil carbon pools comparable to vascular plant-dominated ecosystems, and could arguably be recognized as a unique blue carbon ecosystem. Total ecosystem carbon stocks ranged widely from 2 to 515 Mg C/ha (seagrass bed and mangrove, respectively). Seagrass beds had the lowest carbon stock per unit area, but the largest stock per total area due to their large spatial coverage. Compared to similar ecosystems globally, mangroves and marshes in the UAE have lower plant and soil carbon stocks; however, the difference in soil stocks is far larger than with plant stocks. This incongruent difference between stocks is likely due to poor carbon preservation under conditions of weakly reduced soils (200-350 mV), coarse-grained sediments, and active shoreline migration. This work represents the first attempt to produce a country-wide coastal ecosystem carbon accounting using a uniform sampling protocol, and was motivated by specific policy goals identified by the Abu Dhabi Global

  6. Granular Activated Carbon Performance Capability and Availability.

    Science.gov (United States)

    1983-06-01

    chemicals addressed, and scientific and engineering methods used. Publications were also reviewed for quality and consistency with the bulk of available data...Wastewater by Product Type Journal of Water Pollution 49(6) June 1977 Control Federation 6-M Comunication to . Jackson from Iowa AVP: March 1979...Laboratory 0-38 Reference Data Report - An Informal Comunication National Bureau of Standards April !983 of the National Standard Reference Data System

  7. Environmental implications of carbon limits on market ...

    Science.gov (United States)

    Combined heat and power (CHP) is promoted as an economical, energy-efficient option for combating climate change. To fully examine the viability of CHP as a clean-technology solution, its market potential and impacts need to be analyzed as part of scenarios of the future energy system, particularly those with policies limiting greenhouse gas (GHG) emissions. This paper develops and analyzes scenarios using a bottom-up, technology rich optimization model of the U.S. energy system. Two distinct carbon reduction goals were set up for analysis. In Target 1, carbon emission reduction goals were only included for the electric sector. In Target 2, carbon emission reduction goals were set across the entire energy system with the target patterned after the U.S.’s commitment to reducing GHG emissions as part of the Paris Agreement reached at the COP21 summit. From a system-wide carbon reduction standpoint, Target 2 is significantly more stringent. In addition, these scenarios examine the implications of various CHP capacity expansion and contraction assumptions and energy prices. The largest CHP capacity expansion are observed in scenarios that included Target 1, but investments were scaled back in scenarios that incorporated Target 2. The latter scenario spurred rapid development of zero-emissions technologies within the electric sector, and purchased electricity increased dramatically in many end-use sectors. The results suggest that CHP may play a role in a carbon-c

  8. Calcium availability limits breeding success of passerines on poor soils

    NARCIS (Netherlands)

    Graveland, J; Drent, RH

    1. The role of food in avian reproduction is generally studied from the perspective of the protein and energy demand of birds, This study provides the first experimental evidence that calcium availability may limit reproduction in wild birds as well. 2. Data are presented showing that a large

  9. Calcium availability limits breeding success of passerines on poor soils

    NARCIS (Netherlands)

    Graveland, J.; Drent, R.H.

    1997-01-01

    1. The role of food in avian reproduction is generally studied from the perspective of the protein and energy demand of birds, This study provides the first experimental evidence that calcium availability may limit reproduction in wild birds as well. 2. Data are presented showing that a large

  10. Limitations of wind power availability over Europe: a conceptual study

    Directory of Open Access Journals (Sweden)

    P. Kiss

    2008-11-01

    Full Text Available Wind field statistics are evaluated from the ERA-40 data bank covering a period of 44 years with a temporal resolution of 6 h. Instantaneous wind speed values are provided in geographic cells of size 1°×1° (lat/long for surface (10 m and 1000 hPa pressure heights. Potential wind power generation is estimated in two steps. Firstly, the wind speed at hub height is approximated from surface data based on the statistical analysis of the wind and geopotential records for 1000 hPa pressure level. Secondly, the wind speed values are transformed by an idealised power curve fitted for measured data. The model time series are fed into various hypothetical electric networks. The main quantity of interest is the aggregated output from the networks. A reference power time series is determined for a static network connecting each continental site and an envelope of 1° around the shorelines (representing off-shore locations over Europe. This time series exhibits a low average value and a marked annual periodicity. Wind power integration over limited areas results in higher average outputs at the expense of stronger fluctuations. The long-range spatial correlations of the wind field limit the level of fluctuations strongly which can not be eliminated either by an increase of the area of integration or by dynamic control. This study is fully conceptual, however it demonstrates the limitations of wind power integration over Europe.

  11. Investigation of fundamental limits to beam brightness available from photoinjectors

    International Nuclear Information System (INIS)

    Bazarov, Ivan

    2015-01-01

    The goal of this project was investigation of fundamental limits to beam brightness available from photoinjectors. This basic research in accelerator physics spanned over 5 years aiming to extend the fundamental understanding of high average current, low emittance sources of relativistic electrons based on photoemission guns, a necessary prerequisite for a new generation of coherent X-ray synchrotron radiation facilities based on continuous duty superconducting linacs. The program focused on two areas critical to making advances in the electron source performance: 1) the physics of photocathodes for the production of low emittance electrons and 2) control of space charge forces in the immediate vicinity to the cathode via 3D laser pulse shaping.

  12. Investigation of fundamental limits to beam brightness available from photoinjectors

    Energy Technology Data Exchange (ETDEWEB)

    Bazarov, Ivan [Cornell Univ., Ithaca, NY (United States)

    2015-07-09

    The goal of this project was investigation of fundamental limits to beam brightness available from photoinjectors. This basic research in accelerator physics spanned over 5 years aiming to extend the fundamental understanding of high average current, low emittance sources of relativistic electrons based on photoemission guns, a necessary prerequisite for a new generation of coherent X-ray synchrotron radiation facilities based on continuous duty superconducting linacs. The program focused on two areas critical to making advances in the electron source performance: 1) the physics of photocathodes for the production of low emittance electrons and 2) control of space charge forces in the immediate vicinity to the cathode via 3D laser pulse shaping.

  13. Functional food availability, a limitation to peoples’ health on Islands

    Directory of Open Access Journals (Sweden)

    Patrick Ndungu

    2011-07-01

    Full Text Available Background:All foods are imported to markets in smaller islands in the Caribbean. Before export of foods to these destinations, the foods are subjected to several preservative procedures like irradiation, pesticide spray and prolonged refrigeration etc., to last the extended transport periods. This reduces availability of protective elements and the nutrient contents of the foods to scanty levels,especially to common people with low and middle incomes. Hence the majority of people in these categories on the small islands become vulnerable to ill health. Aims and Objectives: To assess 1. Food availability 2. Normal transport period for foods to reach from the suppliers, and 3. Current level of prevalence of non-infective chronic diseases in the area. Methods: Data were collected from two sources. One set of data was collected from the three supermarkets on the island to obtain information on source, transport time and nature of foods imported; and the second from 200 randomly selected responses of diseased persons for information on the age, gender and cause of death. Results: All the foods were imported and the time taken for the food (including protective foods to reach the island was about 3 weeks. The major causes of death were malignancy (30%, diabetes and its complications (25%, cardio vascular diseases (19.5%, STD / HIV (8.5% and other causes (17.0%. A review of prevalence of chronic diseases like hypertension, diabetes, heart diseases, arthritis and associated functional limitations, in the region reveals that their prevalence is proportionately high on the island compared to nearby developed mainland Functional Foods in Health and Disease 2011; 7:222-231 regions. Body mass index of ≥25 was reported to be as high as 58.3%. The health care facilitiesavailable are seen to be limited and public health activity to prevent or manage the prevailing chronic health issues, appeared to be meager. Conclusion: There is a need to address the

  14. Evaluation of the soil organic carbon, nitrogen and available ...

    African Journals Online (AJOL)

    The result obtained indicates that the level of these chemical properties were generally low as compared to standard measures and parameter for ratings soil fertility in the Nigerian Savanna. Keywords: Status of organic carbon, total nitrogen, available phosphorus, top horizons, research farm. Bowen Journal of Agriculture ...

  15. Limits to the availability of groundwater in Africa

    Science.gov (United States)

    Edmunds, W. Mike

    2012-06-01

    shown, from numerous studies, to be almost entirely non-renewable, 'fossil' water, recharged under wetter early Holocene or late Pleistocene climates, prior to onset of a more arid climate around 4500 years BP (Edmunds et al 2004). Small amounts of modern recharge (for example in the Atlas Mountains or Tibesti) are insufficient to have an impact on the drawdown of distant well fields. It is critical, therefore, to base resource estimates for any development on knowledge of the locally renewable amounts from rainfall and to consider mining palaeo-reserves only as a last resort. Hydrogeological techniques are available to quantify modern recharge (Scanlon and Cook 2002, Scanlon et al 2006) and rates can vary widely according to rock type and landscape; reliance on modelled estimates alone could be misleading. Water quality is also a limiting factor in quantifying usable fresh groundwater storage. In addition to the regional or local problems caused by fluoride, in areas of East and West Africa (MacDonald et al 2012), salinity, above all, will restrict the total usable storage for domestic use and food production, most notably in semi-arid or arid areas. Groundwater salinity arises from various sources, including lithologies containing evaporite minerals, residual sea water (especially in continental coastal margins) and evapotranspiration. As a general rule, salinity increases with depth (older waters tend to more saline), but an additional problem arises where salinity has built up due to aridification over several millennia. Playas and sebkhats are surface expressions of this salinity accumulation from surface water or groundwater discharge, but clearance of native vegetation also increases recharge and leads to salinity increase (George et al 1997). Near-surface salt accumulation may be drawn down into cones of depression in areas of development. One of the largest artesian aquifers, the Continental Intercalaire of Algeria and Tunisia, has groundwater discharge with a

  16. Response of Microbial Soil Carbon Mineralization Rates to Oxygen Limitations

    Science.gov (United States)

    Keiluweit, M.; Denney, A.; Nico, P. S.; Fendorf, S. E.

    2014-12-01

    The rate of soil organic matter (SOM) mineralization is known to be controlled by climatic factors as well as molecular structure, mineral-organic associations, and physical protection. What remains elusive is to what extent oxygen (O2) limitations impact overall rates of microbial SOM mineralization (oxidation) in soils. Even within upland soils that are aerobic in bulk, factors limiting O2 diffusion such as texture and soil moisture can result in an abundance of anaerobic microsites in the interior of soil aggregates. Variation in ensuing anaerobic respiration pathways can further impact SOM mineralization rates. Using a combination of (first) aggregate model systems and (second) manipulations of intact field samples, we show how limitations on diffusion and carbon bioavailability interact to impose anaerobic conditions and associated respiration constraints on SOM mineralization rates. In model aggregates, we examined how particle size (soil texture) and amount of dissolved organic carbon (bioavailable carbon) affect O2 availability and distribution. Monitoring electron acceptor profiles (O2, NO3-, Mn and Fe) and SOM transformations (dissolved, particulate, mineral-associated pools) across the resulting redox gradients, we then determined the distribution of operative microbial metabolisms and their cumulative impact on SOM mineralization rates. Our results show that anaerobic conditions decrease SOM mineralization rates overall, but those are partially offset by the concurrent increases in SOM bioavailability due to transformations of protective mineral phases. In intact soil aggregates collected from soils varying in texture and SOM content, we mapped the spatial distribution of anaerobic microsites. Optode imaging, microsensor profiling and 3D tomography revealed that soil texture regulates overall O2 availability in aggregate interiors, while particulate SOM in biopores appears to control the fine-scale distribution of anaerobic microsites. Collectively, our

  17. Model studies of limitation of carbon dioxide emissions reduction

    International Nuclear Information System (INIS)

    1992-01-01

    The report consists of two papers concerning mitigation of CO 2 emissions in Sweden, ''Limitation of carbon dioxide emissions. Socio-economic effects and the importance of international coordination'', and ''Model calculations for Sweden's energy system with carbon dioxide limitations''. Separate abstracts were prepared for both of the papers

  18. Is oxygen availability a limiting factor for in vitro folliculogenesis?

    Directory of Open Access Journals (Sweden)

    Riccardo Talevi

    Full Text Available Transplantation of ovarian tissue for the preservation of fertility in oncological patients is becoming an accepted clinical practice. However, the risk of re-introducing tumour cells at transplantation has stirred an increased interest for complete in vitro folliculogenesis. This has not yet been achieved in humans possibly for the lack of knowledge on the environmental milieu that orchestrates folliculogenesis in vivo. The main aim of this study was to investigate the effect of oxygen availability on follicle health and growth during in vitro culture of ovarian tissue strips. To this end, a model was developed to predict the dissolved oxygen concentration in tissue under varying culture conditions. Ovarian cortical strips of bovine, adopted as an animal model, and human tissue were cultured in conventional (CD and gas permeable (PD dishes under different media column heights and gaseous oxygen tensions for 3, 6 and 9 days. Follicle quality, activation of primordial follicles to the primary stage, and progression to the secondary stage were analysed through histology. Follicle viability was assessed through a live-dead assay at the confocal scanning laser microscope. Findings showed a higher follicle quality and viability after culture of bovine ovarian strips in PD in adequate medium height and oxygen tensions. The best culture conditions found in the bovine were adopted for human ovarian strip culture and promoted a higher follicle quality, viability and progression. Overall, data demonstrated that modulation of oxygen availability in tissue plays a key role in maintaining follicles' health and their ability to survive and progress to the secondary stage during ovarian tissue in vitro culture. Such culture conditions could increase the yield of healthy secondary follicles for subsequent dissection and individual culture to obtain competent oocytes.

  19. Winter wheat optimizes allocation in response to carbon limitation

    Science.gov (United States)

    Huang, Jianbei; Hammerbacher, Almuth; Trumbore, Susan; Hartmann, Henrik

    2016-04-01

    • Plant photosynthesis is not carbon-saturated at current atmospheric CO2 concentration ([CO2]) thus carbon allocation priority is of critical importance in determining plant response to environmental changes, including increasing [CO2]. • We quantified the percentage of daytime net assimilation (A) allocated to whole-plant nighttime respiration (R) and structural growth (SG), nonstructural carbohydrates (NSC) and secondary metabolites (SMs) during winter wheat (Triticum aestivum) vegetative growth (over 4 weeks) at glacial, ambient, and elevated [CO2] (170, 390 and 680 ppm). • We found that R/A remained relatively constant (11-14%) across [CO2] treatments, whereas plants allocated less C to growth and more C to export at low [CO2] than elevated [CO2]; low [CO2] grown plants tended to invest overall less C into NSC and SMs than to SG due to reduced NSC availability; while leaf SMs/NSC was greater at 170 ppm than at 680 ppm [CO2] this was the opposite for root SMs/NSC; biomass, especially NSC, were preferentially allocated to leaves instead of stems and roots, likely to relieve C limitation induced by low [CO2]. • We conclude that C limitation may force plants to reduce C allocation to long-term survival in order to secure short-term survival. Furthermore, they optimized allocation of the available resource by concentrating biomass and storage to those tissues responsible for assimilation.

  20. Rapid Carbon Assessment Project: Data Summary and Availability

    Science.gov (United States)

    Wills, Skye; Loecke, Terry; Roecker, Stephen; Beaudette, Dylan; Libohova, Zamir; Monger, Curtis; Lindbo, David

    2017-04-01

    , the range within each class overlap and they are not significantly different. As expected, wetlands have the highest SOC stocks, 261 Mg ha-1, and range lands the lowest, 51 Mg ha-1. This is due primarily to the great stocks between 30 and 100cm in wetlands. Ongoing work includes incorporating measurement error into uncertainties and using Bayesian inference to test differences between land use/cover classes. Project information and raw data including sample descriptions, sample data, processing scripts, VNIR scans, and maps are available via web and R based packages. Future work will be done to map carbon across landscapes using environmental covariates and produce probabilities of C concentrations and stocks across multiple land use and management scenarios

  1. Photorespiration and carbon limitation determine productivity in temperate seagrasses.

    Directory of Open Access Journals (Sweden)

    Pimchanok Buapet

    Full Text Available The gross primary productivity of two seagrasses, Zostera marina and Ruppia maritima, and one green macroalga, Ulva intestinalis, was assessed in laboratory and field experiments to determine whether the photorespiratory pathway operates at a substantial level in these macrophytes and to what extent it is enhanced by naturally occurring shifts in dissolved inorganic carbon (DIC and O2 in dense vegetation. To achieve these conditions in laboratory experiments, seawater was incubated with U. intestinalis in light to obtain a range of higher pH and O2 levels and lower DIC levels. Gross photosynthetic O2 evolution was then measured in this pretreated seawater (pH, 7.8-9.8; high to low DIC:O2 ratio at both natural and low O2 concentrations (adjusted by N2 bubbling. The presence of photorespiration was indicated by a lower gross O2 evolution rate under natural O2 conditions than when O2 was reduced. In all three macrophytes, gross photosynthetic rates were negatively affected by higher pH and lower DIC. However, while both seagrasses exhibited significant photorespiratory activity at increasing pH values, the macroalga U. intestinalis exhibited no such activity. Rates of seagrass photosynthesis were then assessed in seawater collected from the natural habitats (i.e., shallow bays characterized by high macrophyte cover and by low DIC and high pH during daytime and compared with open baymouth water conditions (where seawater DIC is in equilibrium with air, normal DIC, and pH. The gross photosynthetic rates of both seagrasses were significantly higher when incubated in the baymouth water, indicating that these grasses can be significantly carbon limited in shallow bays. Photorespiration was also detected in both seagrasses under shallow bay water conditions. Our findings indicate that natural carbon limitations caused by high community photosynthesis can enhance photorespiration and cause a significant decline in seagrass primary production in shallow

  2. Maximum organic carbon limits at different melter feed rates (U)

    International Nuclear Information System (INIS)

    Choi, A.S.

    1995-01-01

    This report documents the results of a study to assess the impact of varying melter feed rates on the maximum total organic carbon (TOC) limits allowable in the DWPF melter feed. Topics discussed include: carbon content; feed rate; feed composition; melter vapor space temperature; combustion and dilution air; off-gas surges; earlier work on maximum TOC; overview of models; and the results of the work completed

  3. Height-related growth declines in ponderosa pine are not due to carbon limitation.

    Science.gov (United States)

    Sala, Anna; Hoch, Günter

    2009-01-01

    Decreased gas exchange as trees grow tall has been proposed to explain age-related growth declines in trees. We examined changes of mobile carbon stores (starch, sugars and lipids) with tree height in ponderosa pine (Pinus ponderosa) at two sites differing in water availability, and tested the following hypotheses: (1) carbon supply does not become increasingly limited as trees grow tall; rather, the concentration of mobile carbon compounds increases with tree height reflecting greater reductions of carbon sink activities relative to carbon assimilation; and (2) increases of stored mobile carbon compounds with tree height are greater in drier sites. Height-related growth reductions were associated with significant increases of non-structural carbohydrates (NSC) and lipid concentrations in all tissues in the upper canopy and of NSC in the bole. Lipid concentrations in the bole decreased with tree height, but such decrease is not necessarily inconsistent with non-limiting carbon supply in tall trees. Furthermore, we found stronger increases of mobile carbon stores with tree height at the dry site relative to the moist site. Our results provide first direct evidence that carbon supply does not limit growth in tall trees and that decreases of water availability might negatively impact growth processes more than net-photosynthesis.

  4. Experiments with the newly available carbon beams at ISOLDE

    CERN Multimedia

    Garcia borge, M J; Koester, U H; Koldste, G T

    2002-01-01

    Recent target-ions-source developments at ISOLDE providing significantly increased yields for carbon isotopes, open up for new and intriguing experiments. We propose to exploit this in two different ways. In particular we wish to do an elastic resonance scattering experiment of $^{9}$C on a proton target to gain information on the particle unbound system $^{10}$N. Furthermore we wish to perform decay experiments of the neutron-rich carbon isotopes, with special focus on $^{17-19}$C but also including a test to see whether the even more neutron-rich isotopes $^{20,22}$C are accessible at ISOLDE.

  5. Temperature effects in an optical limiter using carbon nanotube suspensions

    International Nuclear Information System (INIS)

    Yu, Hyojung; Kim, Sokwon

    2005-01-01

    An optical limiter is an optical component that reduces the laser beam intensity for the protection of eyes and light sensors, and a carbon nanotube is known to be a highly efficient optical limiting material. However, the effects of heat generated by continuous use have not been studied yet. Therefore, in this work, the variation of optical limiting effect of multi-walled carbon-nanotube suspensions in several kinds of solvents such as distilled water, chloroform, ethanol and ethylene glycol, were measured in the temperature range from room temperature to the boiling point of each solvent. A pulsed Nd : YAG laser with a wavelength of 1064 nm and a pulse duration of 6 ns was used as the light source. The experimental result shows that the limiting efficiencies of all the suspensions were reduced as the temperature was increased and that a suspension with a solvent of lower boiling point, viscosity, and surface tension showed a higher efficiency.

  6. 42 CFR 440.255 - Limited services available to certain aliens.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Limited services available to certain aliens. 440... Limits Applicable to All Services § 440.255 Limited services available to certain aliens. (a) FFP for services. FFP is available for services provided to aliens described in this section which are necessary to...

  7. Formation of carbon containing layers on tungsten test limiters

    International Nuclear Information System (INIS)

    Rubel, M.; Philipps, V.; Huber, A.; Tanabe, T.

    1999-01-01

    Tungsten test limiters of mushroom shape and a plasma facing area of approximately 100 cm 2 were exposed at the TEXTOR-94 tokamak to a number of deuterium fuelled discharges performed under various operation conditions. Two types of limiters were tested: a sole tungsten limiter and a twin limiter consisting of two halves, one made of tungsten and another of graphite. The exposed surfaces were examined with ion beam analysis methods and laser profilometry. The formation of some deposition zones was observed near the edges of the limiters. The deuterium-to-carbon concentration ratio was in the range from 0.04 to 0.11 and around 0.2 for the sole tungsten and the twin limiter, respectively. Significant amounts of the co-deposited tungsten and silicon atoms were found on the graphite part of the twin limiter indicating the formation of mixed W-C-Si compounds. (orig.)

  8. The effects of phosphorus limitation on carbon metabolism in diatoms.

    Science.gov (United States)

    Brembu, Tore; Mühlroth, Alice; Alipanah, Leila; Bones, Atle M

    2017-09-05

    Phosphorus is an essential element for life, serving as an integral component of nucleic acids, lipids and a diverse range of other metabolites. Concentrations of bioavailable phosphorus are low in many aquatic environments. Microalgae, including diatoms, apply physiological and molecular strategies such as phosphorus scavenging or recycling as well as adjusting cell growth in order to adapt to limiting phosphorus concentrations. Such strategies also involve adjustments of the carbon metabolism. Here, we review the effect of phosphorus limitation on carbon metabolism in diatoms. Two transcriptome studies are analysed in detail, supplemented by other transcriptome, proteome and metabolite data, to gain an overview of different pathways and their responses. Phosphorus, nitrogen and silicon limitation responses are compared, and similarities and differences discussed. We use the current knowledge to propose a suggestive model for the carbon flow in phosphorus-replete and phosphorus-limited diatom cells.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'. © 2017 The Authors.

  9. The Bistable Behaviour of Pseudomonas putida KT2440 during PHA Depolymerization under Carbon Limitation

    Directory of Open Access Journals (Sweden)

    Stephanie Karmann

    2017-06-01

    Full Text Available Poly(hydroxyalkanoates (PHAs are bacterial polyesters offering a biodegradable alternative to petrochemical plastics. The intracellular formation and degradation of PHAs is a dynamic process that strongly depends on the availability of carbon and other nutrients. Carbon excess and nitrogen limitation are considered to favor PHA accumulation, whereas carbon limitation triggers PHA depolymerization when all other essential nutrients are present in excess. We studied the population dynamics of Pseudomonas putida KT2440 at the single cell level during different physiological conditions, favoring first PHA polymerization during growth on octanoic acid, and then PHA depolymerization during carbon limitation. PHAs accumulate intracellularly in granules, and were proposed to separate preferentially together with nucleic acids, leading to two daughter cells containing approximately equal amounts of PHA. However, we could show that such P. putida KT2440 cells show bistable behavior when exposed to carbon limitation, and separate into two subpopulations: one with high and one with low PHA. This suggests an asymmetric PHA distribution during cell division under carbon limitation, which has a significant influence on our understanding of PHA mobilization.

  10. Carbon impurity transport around limiters in the DITE tokamak

    International Nuclear Information System (INIS)

    Pitcher, C.S.; Stangeby, P.C.; Goodall, D.H.J.; Matthews, G.F.; McCracken, G.M.

    1989-01-01

    The transport of impurity ions originating at the limiter in a tokamak is critically dependent on the location of the ion in the boundary plasma. In the confined plasma, just inboard of the limiter, impurity ions will disperse freely into the discharge whilst in the scrape-off layer the pre-sheath plasma flow and the associated ambipolar electric field may tend to sweep impurities back to the limiter surface. In this paper we have studied, both by experiment and by theory, the transport of carbon impurity ions in the vicinity of the limiter. By comparing experimental measurements of the spatial distributions of impurities around the limiter with that predicted from a Monte Carlo computer code it appears that the parallel dispersal on closed field lines in the confined plasma is consistent with classical transport processes and that in the scrape-off layer the dispersal is indeed impeded by the pre-sheath plasma flow. (orig.)

  11. Growth limit of carbon onions – A continuum mechanical study

    DEFF Research Database (Denmark)

    Todt, Melanie; Bitsche, Robert; Hartmann, Markus A.

    2014-01-01

    of carbon onions and, thus, can be a reason for the limited size of such particles. The loss of stability is mainly evoked by van der Waals interactions between misfitting neighboring layers leading to self-equilibrating stress states in the layers due to mutual accommodation. The influence of the curvature......The growth of carbon onions is simulated using continuum mechanical shell models. With this models it is shown that, if a carbon onion has grown to a critical size, the formation of an additional layer leads to the occurrence of a structural instability. This instability inhibits further growth...... induced surface energy and its consequential stress state is investigated and found to be rather negligible. Furthermore, it is shown that the nonlinear character of the van der Waals interactions has to be considered to obtain maximum layer numbers comparable to experimental observations. The proposed...

  12. Carbon Monoxide in Meat and Fish Packaging: Advantages and Limits

    Directory of Open Access Journals (Sweden)

    Djamel Djenane

    2018-01-01

    Full Text Available Due to increased demands for greater expectation in relation to quality, convenience, safety and extended shelf-life, combined with growing demand from retailers for cost-effective extensions of fresh muscle foods’ shelf-life, the food packaging industry quickly developed to meet these expectations. During the last few decades, modified atmosphere packaging (MAP of foods has been a promising area of research, but much remains to be known regarding the use of unconventional gases such carbon monoxide (CO. The use of CO for meat and seafood packaging is not allowed in most countries due to the potential toxic effect, and its use is controversial in some countries. The commercial application of CO in food packaging was not then considered feasible because of possible environmental hazards for workers. CO has previously been reported to mask muscle foods’ spoilage, and this was the primary concern raised for the prohibition, as this may mislead consumers. This review was undertaken to present the most comprehensive and current overview of the widely-available, scattered information about the use of CO in the preservation of muscle foods. The advantages of CO and its industrial limits are presented and discussed. The most recent literature on the consumer safety issues related to the use of CO and consumer acceptance of CO especially in meat packaging systems were also discussed. Recommendations and future prospects were addressed for food industries, consumers and regulators on what would be a “best practice” in the use of CO in food packaging. All this promotes high ethical standards in commercial communications by means of effective regulation, for the benefit of consumers and businesses in the world, and this implies that industrialized countries and members of their regulatory agencies must develop a coherent and robust systems of regulation and control that can respond effectively to new challenges.

  13. Effects of phosphorus availability and vesicular-arbuscular mycorrhizas on the carbon budget of common bean (Phaseolus vulgaris)

    NARCIS (Netherlands)

    Nielsen, K.F.; Bouma, T.J.; Lynch, J.P.; Eissenstat, D.M.

    1998-01-01

    Low phosphorus availability is often a primary constraint to plant productivity in native soils. Here we test the hypothesis that root carbon costs are a primary limitation to plant growth in low P soils by assessing the effect of P availability and mycorrhizal infection on whole plant C budgets in

  14. Does limited data availability prevent adequate water use estimates on farm scale?

    Science.gov (United States)

    Kayatz, Benjamin; Kuster, Benjamin; Percy, Barbara; Hillier, Jonathan; Freese, Dirk; Wattenbach, Martin

    2015-04-01

    Increasing food production for a growing world population and at the same time mitigating climate change as well as adapting to its consequences is one of the key global challenges. Therefore producing crops with fewer resources such as water and fertilizers and less emissions of greenhouse gases is an important question that has to be answered on farm scale. The cool farm tool (CFT) is a farm scale emission calculator and was developed in 2010 to help farmers to reduce their carbon footprint. In order to adapt to future climate change an easy to use and at the same time robust water footprinting tool is needed for the CFT to take a more holistic approach on environmental sustainability. However data on farm level is often scarce. We investigated the effect of limited data on actual evapotranspiration using the FAO56 standard to assess the quality of farm water footprint estimates. Calculations are based on various agricultural sites from the Fluxnet database and estimates are compared to eddy covariance measurements. Results show that higher data availability is not directly linked to more accurate estimates of actual evapotranspiration. Estimates based only on temperature and relative humidity are still able to reproduce daily patterns. However cumulative values over one growing season show a considerable offset to eddy covariance observations for all data input levels. Finding the optimum between data requirements and an accuracy that fulfills farmer needs is crucial. Engagement of farmers and using a global network as the Fluxnet database will help to achieve this goal.

  15. Carbon Monoxide in Meat and Fish Packaging: Advantages and Limits

    Science.gov (United States)

    Roncalés, Pedro

    2018-01-01

    Due to increased demands for greater expectation in relation to quality, convenience, safety and extended shelf-life, combined with growing demand from retailers for cost-effective extensions of fresh muscle foods’ shelf-life, the food packaging industry quickly developed to meet these expectations. During the last few decades, modified atmosphere packaging (MAP) of foods has been a promising area of research, but much remains to be known regarding the use of unconventional gases such carbon monoxide (CO). The use of CO for meat and seafood packaging is not allowed in most countries due to the potential toxic effect, and its use is controversial in some countries. The commercial application of CO in food packaging was not then considered feasible because of possible environmental hazards for workers. CO has previously been reported to mask muscle foods’ spoilage, and this was the primary concern raised for the prohibition, as this may mislead consumers. This review was undertaken to present the most comprehensive and current overview of the widely-available, scattered information about the use of CO in the preservation of muscle foods. The advantages of CO and its industrial limits are presented and discussed. The most recent literature on the consumer safety issues related to the use of CO and consumer acceptance of CO especially in meat packaging systems were also discussed. Recommendations and future prospects were addressed for food industries, consumers and regulators on what would be a “best practice” in the use of CO in food packaging. All this promotes high ethical standards in commercial communications by means of effective regulation, for the benefit of consumers and businesses in the world, and this implies that industrialized countries and members of their regulatory agencies must develop a coherent and robust systems of regulation and control that can respond effectively to new challenges. PMID:29360803

  16. 40 CFR 450.22 - Effluent limitations reflecting the best available technology economically achievable (BAT).

    Science.gov (United States)

    2010-07-01

    ... best available technology economically achievable (BAT). 450.22 Section 450.22 Protection of... limitations reflecting the best available technology economically achievable (BAT). Except as provided in 40... the best available technology economically achievable (BAT). (a) Beginning no later than August 1...

  17. Maximum total organic carbon limit for DWPF melter feed

    International Nuclear Information System (INIS)

    Choi, A.S.

    1995-01-01

    DWPF recently decided to control the potential flammability of melter off-gas by limiting the total carbon content in the melter feed and maintaining adequate conditions for combustion in the melter plenum. With this new strategy, all the LFL analyzers and associated interlocks and alarms were removed from both the primary and backup melter off-gas systems. Subsequently, D. Iverson of DWPF- T ampersand E requested that SRTC determine the maximum allowable total organic carbon (TOC) content in the melter feed which can be implemented as part of the Process Requirements for melter feed preparation (PR-S04). The maximum TOC limit thus determined in this study was about 24,000 ppm on an aqueous slurry basis. At the TOC levels below this, the peak concentration of combustible components in the quenched off-gas will not exceed 60 percent of the LFL during off-gas surges of magnitudes up to three times nominal, provided that the melter plenum temperature and the air purge rate to the BUFC are monitored and controlled above 650 degrees C and 220 lb/hr, respectively. Appropriate interlocks should discontinue the feeding when one or both of these conditions are not met. Both the magnitude and duration of an off-gas surge have a major impact on the maximum TOC limit, since they directly affect the melter plenum temperature and combustion. Although the data obtained during recent DWPF melter startup tests showed that the peak magnitude of a surge can be greater than three times nominal, the observed duration was considerably shorter, on the order of several seconds. The long surge duration assumed in this study has a greater impact on the plenum temperature than the peak magnitude, thus making the maximum TOC estimate conservative. Two models were used to make the necessary calculations to determine the TOC limit

  18. The synthesis of PdPt/carbon paper via surface limited redox replacement reactions for oxygen reduction reaction

    CSIR Research Space (South Africa)

    Motsoeneng, RG

    2015-09-01

    Full Text Available Surface-limited redox replacement reactions using the electrochemical atomic layer deposition (EC-ALD) technique were used to synthesize PdPt bimetallic electrocatalysts on carbon paper substrate. Electrocatalysts having different Pd:Pt ratio were...

  19. Photorespiration and carbon limitation determine productivity in temperate seagrasses.

    Science.gov (United States)

    Buapet, Pimchanok; Rasmusson, Lina M; Gullström, Martin; Björk, Mats

    2013-01-01

    The gross primary productivity of two seagrasses, Zostera marina and Ruppia maritima, and one green macroalga, Ulva intestinalis, was assessed in laboratory and field experiments to determine whether the photorespiratory pathway operates at a substantial level in these macrophytes and to what extent it is enhanced by naturally occurring shifts in dissolved inorganic carbon (DIC) and O2 in dense vegetation. To achieve these conditions in laboratory experiments, seawater was incubated with U. intestinalis in light to obtain a range of higher pH and O2 levels and lower DIC levels. Gross photosynthetic O2 evolution was then measured in this pretreated seawater (pH, 7.8-9.8; high to low DIC:O2 ratio) at both natural and low O2 concentrations (adjusted by N2 bubbling). The presence of photorespiration was indicated by a lower gross O2 evolution rate under natural O2 conditions than when O2 was reduced. In all three macrophytes, gross photosynthetic rates were negatively affected by higher pH and lower DIC. However, while both seagrasses exhibited significant photorespiratory activity at increasing pH values, the macroalga U. intestinalis exhibited no such activity. Rates of seagrass photosynthesis were then assessed in seawater collected from the natural habitats (i.e., shallow bays characterized by high macrophyte cover and by low DIC and high pH during daytime) and compared with open baymouth water conditions (where seawater DIC is in equilibrium with air, normal DIC, and pH). The gross photosynthetic rates of both seagrasses were significantly higher when incubated in the baymouth water, indicating that these grasses can be significantly carbon limited in shallow bays. Photorespiration was also detected in both seagrasses under shallow bay water conditions. Our findings indicate that natural carbon limitations caused by high community photosynthesis can enhance photorespiration and cause a significant decline in seagrass primary production in shallow waters.

  20. Nutrient availability limits biological production in Arctic sea ice melt ponds

    DEFF Research Database (Denmark)

    Sørensen, Heidi Louise; Thamdrup, Bo; Jeppesen, Erik

    2017-01-01

    nutrient limitation in melt ponds. We also document that the addition of nutrients, although at relative high concentrations, can stimulate biological productivity at several trophic levels. Given the projected increase in first-year ice, increased melt pond coverage during the Arctic spring and potential......Every spring and summer melt ponds form at the surface of polar sea ice and become habitats where biological production may take place. Previous studies report a large variability in the productivity, but the causes are unknown. We investigated if nutrients limit the productivity in these first...... additional nutrient supply from, e.g. terrestrial sources imply that biological activity of melt ponds may become increasingly important for the sympagic carbon cycling in the future Arctic....

  1. Availability of limited service food outlets surrounding schools in British Columbia.

    Science.gov (United States)

    Black, Jennifer L; Day, Meghan

    2012-06-05

    The purpose of this study was to provide a descriptive profile of the availability of limited service food outlets surrounding public schools in British Columbia, Canada. Data from the 2010 Canadian Business Data Files were used to identify limited service food outlets including fast food outlets, beverage and snack food stores, delis and convenience stores. The number of food outlets within 800 metres of 1,392 public schools and the distance from schools to the nearest food outlets were assessed. Multivariate regression models examined the associations between food outlet availability and school-level characteristics. In 2010, over half of the public schools in BC (54%) were located within a 10-12 minute walk from at least one limited service food outlet. The median closest distance to a food outlet was just over 1 km (1016 m). Schools comprised of students living in densely populated urban neighbourhoods and neighbourhoods characterized by lower socio-economic status were more likely to have access to limited service food outlets within walking distance. After adjusting for school-level median family income and population density, larger schools had higher odds of exposure to food vendors compared to schools with fewer students. The availability of and proximity to limited service food outlets vary widely across schools in British Columbia and school-level characteristics are significantly associated with food outlet availability. Additional research is needed to understand how food environment exposures inside and surrounding schools impact students' attitudes, food choices and dietary quality.

  2. Carbon availability for the fungus triggers nitrogen uptake and transport in the arbuscular mycorrhizal symbiosis

    Science.gov (United States)

    The arbuscular mycorrhizal (AM) symbiosis is characterized by a transfer of nutrients in exchange for carbon. We tested the effect of the carbon availability for the AM fungus Glomus intraradices on nitrogen (N) uptake and transport in the symbiosis. We followed the uptake and transport of 15N and ...

  3. Optimal Plant Carbon Allocation Implies a Biological Control on Nitrogen Availability

    Science.gov (United States)

    Prentice, I. C.; Stocker, B. D.

    2015-12-01

    The degree to which nitrogen availability limits the terrestrial C sink under rising CO2 is a key uncertainty in carbon cycle and climate change projections. Results from ecosystem manipulation studies and meta-analyses suggest that plant C allocation to roots adjusts dynamically under varying degrees of nitrogen availability and other soil fertility parameters. In addition, the ratio of biomass production to GPP appears to decline under nutrient scarcity. This reflects increasing plant C exudation into the soil (Cex) with decreasing nutrient availability. Cex is consumed by an array of soil organisms and may imply an improvement of nutrient availability to the plant. Thus, N availability is under biological control, but incurs a C cost. In spite of clear observational support, this concept is left unaccounted for in Earth system models. We develop a model for the coupled cycles of C and N in terrestrial ecosystems to explore optimal plant C allocation under rising CO2 and its implications for the ecosystem C balance. The model follows a balanced growth approach, accounting for the trade-offs between leaf versus root growth and Cex in balancing C fixation and N uptake. We assume that Cex is proportional to root mass, and that the ratio of N uptake (Nup) to Cex is proportional to inorganic N concentration in the soil solution. We further assume that Cex is consumed by N2-fixing processes if the ratio of Nup:Cex falls below the inverse of the C cost of N2-fixation. Our analysis thereby accounts for the feedbacks between ecosystem C and N cycling and stoichiometry. We address the question of how the plant C economy will adjust under rising atmospheric CO2 and what this implies for the ecosystem C balance and the degree of N limitation.

  4. 76 FR 46793 - Jordan Hydroelectric Limited Partnership; Notice of Availability of Environmental Assessment

    Science.gov (United States)

    2011-08-03

    ... Hydroelectric Limited Partnership; Notice of Availability of Environmental Assessment In accordance with the... for an original license for the 3.0-megawatt (MW) Flannagan Hydroelectric Project located on the Pound..., NE., Room 1-A, Washington, DC 20426. Please affix ``Flannagan Hydroelectric Project No. 12740-003...

  5. 76 FR 71967 - Jordan Hydroelectric Limited Partnership; Notice of Availability of Final Environmental Assessment

    Science.gov (United States)

    2011-11-21

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 12740-003-VA] Jordan Hydroelectric Limited Partnership; Notice of Availability of Final Environmental Assessment In accordance with... application for an original license for the 3.0-megawatt (MW) Flannagan Hydroelectric Project located on the...

  6. 76 FR 70437 - Jordan Hydroelectric Limited Partnership; Notice of Availability of Final Environmental Assessment

    Science.gov (United States)

    2011-11-14

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [ Project No. 12737-002] Jordan Hydroelectric Limited Partnership; Notice of Availability of Final Environmental Assessment In accordance with... original license for the 3.7-megawatt (MW) Gathright Hydroelectric Project located on the Jackson River in...

  7. Limiting factor analysis of high availability nuclear plants (boiling water reactors). Final report

    International Nuclear Information System (INIS)

    Frederick, L.G.; Brady, R.M.; Shor, S.W.W.; McCusker, J.T.; Alden, W.M.; Kovacs, S.

    1979-08-01

    The pertinent results are presented of a 16-month study conducted for Electric Power Research Institute by General Electric Company, Bechtel Power Corporation, and Philadelphia Electric Company. The study centered around the Peach Bottom 2 Atomic Power Station, but also included limited study of operations at 20 additional operating boiling water reactors. The purpose of the study was to identify and evaluate key factors limiting plant availability, and to identify potential improvements for eliminating or alleviating those limitations. The key limiting factors were found to be refueling activities; activities related to the reactor fuel; reactor scrams; activities related to 20 operating systems or major components; delays due to radiation, turbid water during refueling operations, facilities/working conditions, and dirt/foreign material; and general maintenance/repair of valves and piping. Existing programs to reduce the effect on plant unavailability are identified, and suggestions for further action are made

  8. Nutrient limitation reduces land carbon uptake in simulations with a model of combined carbon, nitrogen and phosphorus cycling

    Directory of Open Access Journals (Sweden)

    D. S. Goll

    2012-09-01

    Full Text Available Terrestrial carbon (C cycle models applied for climate projections simulate a strong increase in net primary productivity (NPP due to elevated atmospheric CO2 concentration during the 21st century. These models usually neglect the limited availability of nitrogen (N and phosphorus (P, nutrients that commonly limit plant growth and soil carbon turnover. To investigate how the projected C sequestration is altered when stoichiometric constraints on C cycling are considered, we incorporated a P cycle into the land surface model JSBACH (Jena Scheme for Biosphere–Atmosphere Coupling in Hamburg, which already includes representations of coupled C and N cycles.

    The model reveals a distinct geographic pattern of P and N limitation. Under the SRES (Special Report on Emissions Scenarios A1B scenario, the accumulated land C uptake between 1860 and 2100 is 13% (particularly at high latitudes and 16% (particularly at low latitudes lower in simulations with N and P cycling, respectively, than in simulations without nutrient cycles. The combined effect of both nutrients reduces land C uptake by 25% compared to simulations without N or P cycling. Nutrient limitation in general may be biased by the model simplicity, but the ranking of limitations is robust against the parameterization and the inflexibility of stoichiometry. After 2100, increased temperature and high CO2 concentration cause a shift from N to P limitation at high latitudes, while nutrient limitation in the tropics declines. The increase in P limitation at high-latitudes is induced by a strong increase in NPP and the low P sorption capacity of soils, while a decline in tropical NPP due to high autotrophic respiration rates alleviates N and P limitations. The quantification of P limitation remains challenging. The poorly constrained processes of soil P sorption and biochemical mineralization are identified as the main uncertainties in the strength of P limitation

  9. Soil fertility limits carbon sequestration by forest ecosystems in a CO2-enriched atmosphere

    Science.gov (United States)

    Ram Oren; David S. Ellsworth; Kurt H. Johnsen; Nathan Phillips; Brent E. Ewers; Chris Maier; Karina V.R. Schafer; Heather McCarthy; George Hendrey; Steven G. McNulty; Gabriel G. Katul

    2001-01-01

    Northern mid-latitude forests are a large terrestrial carbon sink. Ignoring nutrient limitations, large increases in carbon sequestration from carbon dioxide (CO2) fertilization are expected in these forests. Yet, forests are usually relegated to sites of moderate to poor fertility, where tree growth is often limited by nutrient supply, in...

  10. Examining possible relationship between carbon finance availability and growth of wind energy

    Directory of Open Access Journals (Sweden)

    Collins C Ngwakwe

    2014-09-01

    Full Text Available This paper evaluates the possible relationship between carbon fund availability and the growth of wind energy. This has become apposite considering global quest for renewable energies as a veritable option for carbon reduction and sustainable development. Whilst some extant literature blames delay in climate policy as an obstacle to green energy, others regard carbon finance availability as a booster to renewable energy. Raging argument is that similar to any other investment, renewable energy finance availability may mar or catalyse growth in renewable energy. Consequently, in this paper, a conceptual overview of carbon finance and renewable energy is undertaken and a test of the relationship between the World Bank carbon finance availability and wind energy growth is conducted. The result indicates a significant positive relationship between World Bank carbon financing and global growth in wind energy. The paper thus concludes that aside from policy options, renewable energy financing seems to be a contributory catalyst that may spur improvement in global renewable energy. The paper highlights that achieving green economic development in developing countries would depend, not only on climate policies alone, but also on sustainable financing. Hence government and private sources of funding is very desirable in achieving global green economic development, most importantly, for developing economies. The paper thus offers a research agenda on awareness creating for local and international sources of green energy for developing countries.

  11. Seasonal dynamics of mobile carbon supply in Quercus aquifolioides at the upper elevational limit.

    Directory of Open Access Journals (Sweden)

    Wan-Ze Zhu

    Full Text Available Many studies have tried to explain the physiological mechanisms of the alpine treeline phenomenon, but the debate on the alpine treeline formation remains controversial due to opposite results from different studies. The present study explored the carbon-physiology of an alpine shrub species (Quercus aquifolioides grown at its upper elevational limit compared to lower elevations, to test whether the elevational limit of alpine shrubs (<3 m in height are determined by carbon limitation or growth limitation. We studied the seasonal variations in non-structural carbohydrate (NSC and its pool size in Q. aquifolioides grown at 3000 m, 3500 m, and at its elevational limit of 3950 m above sea level (a.s.l. on Zheduo Mt., SW China. The tissue NSC concentrations along the elevational gradient varied significantly with season, reflecting the season-dependent carbon balance. The NSC levels in tissues were lowest at the beginning of the growing season, indicating that plants used the winter reserve storage for re-growth in the early spring. During the growing season, plants grown at the elevational limit did not show lower NSC concentrations compared to plants at lower elevations, but during the winter season, storage tissues, especially roots, had significantly lower NSC concentrations in plants at the elevational limit compared to lower elevations. The present results suggest the significance of winter reserve in storage tissues, which may determine the winter survival and early-spring re-growth of Q. aquifolioides shrubs at high elevation, leading to the formation of the uppermost distribution limit. This result is consistent with a recent hypothesis for the alpine treeline formation.

  12. Limits to the potential of bio-fuels and bio-sequestration of carbon

    International Nuclear Information System (INIS)

    Pearman, Graeme I.

    2013-01-01

    This document examines bio-physical limits of bio-fuels and bio-sequestration of carbon by examining available solar radiation and observed efficiencies with which natural ecosystems and agricultural systems convert that energy to biomass. It compares these energy/carbon exchanges with national levels of energy use and carbon emissions for Australia, Brazil, China, Japan, Republic of Korea, New Zealand, Papua New Guinea, Singapore, Sweden, United Kingdom and United States. Globally primary energy consumption (related carbon emissions) is currently equivalent to ∼0.06% of the incident solar energy, and 43% of the energy (carbon) captured by photosynthesis. The nations fall into three categories. Those with primary energy consumption that is: 1–10% (Japan, Korea and Singapore); ∼0.1% (China, UK and the US) and; 0.1–0.01% (Australia, Brazil, Papua New Guinea, New Zealand and Sweden) of incident solar radiation. The percentage of energy captured in biomass follows this pattern, but generally lower by ∼3 orders of magnitude. The energy content of traded wheat, corn and rice represents conversion efficiencies of solar radiation of 0.08–0.17% and for sugar close to 1%, ignoring energy use in production and conversion of biomass to fuels. The study implies that bio-fuels or bio-sequestration can only be a small part of an inclusive portfolio of actions towards a low carbon future and minimised net emissions of carbon to the atmosphere. - Highlights: • Global energy consumption is ∼0.06% of solar; 43% of net primary production. • 11 nations studied fall into 3 groups: consumption/solar=1–10%; ∼0.1%; 0.1–0.01%. • % of energy captured in biomass is lower by ∼3 orders of magnitude. • Crops and natural ecosystems capture 0.1–0.3% and sugar 1% of solar energy. • Significant bio-energy/carbon sequestration via biomass is unrealistic

  13. Dilution limits dissolved organic carbon utilization in the deep ocean

    NARCIS (Netherlands)

    Arrieta, J.M.; Mayol, E.; Hansman, R.L.; Herndl, G.J.; Dittmar, T.; Duarte, C.M.

    2015-01-01

    Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An

  14. Reactor limitation system improves the safety and availability of the Angra 2 nuclear power plant

    International Nuclear Information System (INIS)

    Souza Mendes, J.E. de

    1987-01-01

    Beyond the classic Reactor Protection System and Reactor Control System, nuclear plant Angra 2 has a third system called Reactor Limitation System which combines the intelligence features of the control systems with the high reliability of the protection systems. In determined events, which are not controlled by the control system (e.g.: load rejection, failure of one main reactor coolant pump), the Reactor Limitation System actuates automatically in order to lead the plant to a safe operating condition and so it avoids the actuation of the Reactor Protection System and consequently the reactor trip. This increases safety and availability of the plant and reduces component stresses. After the safe operating condition is reached, the process guidance automatically returns to the control systems. (Author) [pt

  15. Manganese availability is negatively associated with carbon storage in northern coniferous forest humus layers.

    Science.gov (United States)

    Stendahl, Johan; Berg, Björn; Lindahl, Björn D

    2017-11-14

    Carbon sequestration below ground depends on organic matter input and decomposition, but regulatory bottlenecks remain unclear. The relative importance of plant production, climate and edaphic factors has to be elucidated to better predict carbon storage in forests. In Swedish forest soil inventory data from across the entire boreal latitudinal range (n = 2378), the concentration of exchangeable manganese was singled out as the strongest predictor (R 2  = 0.26) of carbon storage in the extensive organic horizon (mor layer), which accounts for one third of the total below ground carbon. In comparison, established ecosystem models applied on the same data have failed to predict carbon stocks (R 2  < 0.05), and in our study manganese availability overshadowed both litter production and climatic factors. We also identified exchangeable potassium as an additional strong predictor, however strongly correlated with manganese. The negative correlation between manganese and carbon highlights the importance of Mn-peroxidases in oxidative decomposition of recalcitrant organic matter. The results support the idea that the fungus-driven decomposition could be a critical factor regulating humus carbon accumulation in boreal forests, as Mn-peroxidases are specifically produced by basidiomycetes.

  16. Energy saving in WWTP: Daily benchmarking under uncertainty and data availability limitations.

    Science.gov (United States)

    Torregrossa, D; Schutz, G; Cornelissen, A; Hernández-Sancho, F; Hansen, J

    2016-07-01

    Efficient management of Waste Water Treatment Plants (WWTPs) can produce significant environmental and economic benefits. Energy benchmarking can be used to compare WWTPs, identify targets and use these to improve their performance. Different authors have performed benchmark analysis on monthly or yearly basis but their approaches suffer from a time lag between an event, its detection, interpretation and potential actions. The availability of on-line measurement data on many WWTPs should theoretically enable the decrease of the management response time by daily benchmarking. Unfortunately this approach is often impossible because of limited data availability. This paper proposes a methodology to perform a daily benchmark analysis under database limitations. The methodology has been applied to the Energy Online System (EOS) developed in the framework of the project "INNERS" (INNovative Energy Recovery Strategies in the urban water cycle). EOS calculates a set of Key Performance Indicators (KPIs) for the evaluation of energy and process performances. In EOS, the energy KPIs take in consideration the pollutant load in order to enable the comparison between different plants. For example, EOS does not analyse the energy consumption but the energy consumption on pollutant load. This approach enables the comparison of performances for plants with different loads or for a single plant under different load conditions. The energy consumption is measured by on-line sensors, while the pollutant load is measured in the laboratory approximately every 14 days. Consequently, the unavailability of the water quality parameters is the limiting factor in calculating energy KPIs. In this paper, in order to overcome this limitation, the authors have developed a methodology to estimate the required parameters and manage the uncertainty in the estimation. By coupling the parameter estimation with an interval based benchmark approach, the authors propose an effective, fast and reproducible

  17. On the limits of CO2 capture capacity of carbons

    OpenAIRE

    Fernández Martín, Claudia; González Plaza, Marta; Pis Martínez, José Juan; Rubiera González, Fernando; Pevida García, Covadonga; Álvarez Centeno, Teresa

    2010-01-01

    This study shows that standard techniques used for carbons characterization, such as physical adsorption of CO2 at 273 K and N2 at 77 K, can be used to assess, with a good accuracy, the maximum capacity of carbons to capture CO2 under post- and pre-combustion conditions. The analysis of the corresponding adsorption isotherms, within the general theoretical framework of Dubinin's theory, leads to the values of the micropore volume, Wo, and the characteristic energy, Eo, of the carbons, which p...

  18. Allowable exposure limits for carbon dioxide during extravehicular activity

    Science.gov (United States)

    Seter, Andrew J.

    1993-01-01

    The intent was to review the research pertaining to human exposure to carbon dioxide (CO2) and to recommend allowable exposure limits for extravehicular activity (EVA). Respiratory, renal, and gastrointestinal systems may be adversely affected by chronic low dose CO2 exposure. Ventilation was increased 15 percent with 1 percent CO2 and 50 percent with 2 percent CO2. Chronic exposure to less than 2 percent CO2 led to 20 day cycles of uncompensated and compensated respiratory acidosis. Acid-base changes were small. Histopathologic changes in guinea pig lungs have been noted with long term exposure to 1 percent CO2. No changes were seen with exposure to 0.5 percent CO2. Cycling of bone calcium stores with associated changes in blood and urinary calcium levels occurs with long term CO2 exposure. Histologic changes in bone have been noted in guinea pigs exposed to 1 percent CO2. Renal calcification has been noted in guinea pigs with exposure to as low as 0.5 percent CO2. An increase in gastric acidity was noted in subjects with long term exposure to 1 percent CO2. Cardiovascular and neurologic function were largely unaffected. A decrease in the incidence of respiratory, renal, and gastrointestinal disease was noted in submariners coincident with a decrease in ambient CO2 from 1.2 percent to 0.8-0.9 percent. Oxygen (O2) and CO2 stimulate respiration independently and cumulatively. The addition of CO2 to high dose O2 led to the faster onset of seizure activity in mice. Experiments evaluating the physiologic responses to intermittent, repetitive exposures to low dose CO2 and 100 percent O2 mixtures should be performed. A reduction in the current NASA standard for CO2 exposure during EVA of 1 percent (7.6 mmHg) for nominal and 2 percent (15.2 mmHg) for heavy exertion to 0.5 percent (3.8 mmHg) for nominal and 1 percent (7.6 mmHg) for heavy exertion may be prudent. At a minimum, the current NASA standard should not be liberalized.

  19. Large scale surveys suggest limited mercury availability in tropical north Queensland (Australia)

    International Nuclear Information System (INIS)

    Jardine, Timothy D.; Halliday, Ian A.; Howley, Christina; Sinnamon, Vivian; Bunn, Stuart E.

    2012-01-01

    Little is known about the threat of mercury (Hg) to consumers in food webs of Australia's wet–dry tropics. This is despite high concentrations in similar biomes elsewhere and a recent history of gold mining that could lead to a high degree of exposure for biota. We analysed Hg in water, sediments, invertebrates and fishes in rivers and estuaries of north Queensland, Australia to determine its availability and biomagnification in food webs. Concentrations in water and sediments were low relative to other regions of Hg concern, with only four of 138 water samples and five of 60 sediment samples above detection limits of 0.1 μg L −1 and 0.1 μg g −1 , respectively. Concentrations of Hg in fishes and invertebrates from riverine and wetland food webs were well below international consumption guidelines, including those in piscivorous fishes, likely due to low baseline concentrations and limited rates of biomagnification (average slope of log Hg vs. δ 15 N = 0.08). A large fish species of recreational, commercial, and cultural importance (the barramundi, Lates calcarifer), had low concentrations that were below consumption guidelines. Observed variation in Hg concentrations in this species was primarily explained by age and foraging location (floodplain vs. coastal), with floodplain feeders having higher Hg concentrations than those foraging at sea. These analyses suggest that there is a limited threat of Hg exposure for fish-eating consumers in this region. - Highlights: ► Hg concentrations in freshwaters and sediments of north Queensland were low. ► Biomagnification of Hg through riverine food webs was limited. ► Barramundi, a predatory fish, had low concentrations meaning low risk for consumers. ► Floodplain-feeding barramundi had higher Hg concentrations than coastal feeders.

  20. Time-resolved analysis of nonlinear optical limiting for laser synthesized carbon nanoparticles

    Science.gov (United States)

    Chen, G. X.; Hong, M. H.

    2010-11-01

    Nonlinear optical limiting materials have attracted much research interest in recent years. Carbon nanoparticles suspended in liquids show a strong nonlinear optical limiting function. It is important to investigate the nonlinear optical limiting process of carbon nanoparticles for further improving their nonlinear optical limiting performance. In this study, carbon nanoparticles were prepared by laser ablation of a carbon target in tetrahydrofuran (THF). Optical limiting properties of the samples were studied with 532-nm laser light, which is in the most sensitive wavelength band for human eyes. The shape of the laser pulse plays an important role for initializing the nonlinear optical limiting effect. Time-resolved analysis of laser pulses discovered 3 fluence stages of optical limiting. Theoretical simulation indicates that the optical limiting is initialized by a near-field optical enhancement effect.

  1. TOR Signaling Promotes Accumulation of BZR1 to Balance Growth with Carbon Availability in Arabidopsis.

    Science.gov (United States)

    Zhang, Zhenzhen; Zhu, Jia-Ying; Roh, Jeehee; Marchive, Chloé; Kim, Seong-Ki; Meyer, Christian; Sun, Yu; Wang, Wenfei; Wang, Zhi-Yong

    2016-07-25

    For maintenance of cellular homeostasis, the actions of growth-promoting hormones must be attenuated when nutrient and energy become limiting. The molecular mechanisms that coordinate hormone-dependent growth responses with nutrient availability remain poorly understood in plants [1, 2]. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator that integrates nutrient and energy signaling to regulate growth and homeostasis in both animals and plants [3-7]. Here, we show that sugar signaling through TOR controls the accumulation of the brassinosteroid (BR)-signaling transcription factor BZR1, which is essential for growth promotion by multiple hormonal and environmental signals [8-11]. Starvation, caused by shifting of light-grown Arabidopsis seedlings into darkness, as well as inhibition of TOR by inducible RNAi, led to plant growth arrest and reduced expression of BR-responsive genes. The growth arrest caused by TOR inactivation was partially recovered by BR treatment and the gain-of-function mutation bzr1-1D, which causes accumulation of active forms of BZR1 [12]. Exogenous sugar promoted BZR1 accumulation and seedling growth, but such sugar effects were largely abolished by inactivation of TOR, whereas the effect of TOR inactivation on BZR1 degradation is abolished by inhibition of autophagy and by the bzr1-1D mutation. These results indicate that cellular starvation leads sequentially to TOR inactivation, autophagy, and BZR1 degradation. Such regulation of BZR1 accumulation by glucose-TOR signaling allows carbon availability to control the growth promotion hormonal programs, ensuring supply-demand balance in plant growth. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Effect of light availability on dissolved organic carbon release by Caribbean reef algae and corals

    NARCIS (Netherlands)

    Mueller, B.; van der Zande, R.M.; van Leent, P.J.M.; Meesters, E.H.; Vermeij, M.J.A.; van Duyl, F.C.

    2014-01-01

    Dissolved organic carbon (DOC) release of three algal and two coral species was determined at three light intensities (0, 30–80, and 200–400 µmol photons m–2 s–1) in ex situ incubations to quantify the effect of light availability on DOC release by reef primary producers. DOC release of three

  3. Optimizing Regional Food and Energy Production under Limited Water Availability through Integrated Modeling

    Directory of Open Access Journals (Sweden)

    Junlian Gao

    2018-05-01

    Full Text Available Across the world, human activity is approaching planetary boundaries. In northwest China, in particular, the coal industry and agriculture are competing for key limited inputs of land and water. In this situation, the traditional approach to planning the development of each sector independently fails to deliver sustainable solutions, as solutions made in sectorial ‘silos’ are often suboptimal for the entire economy. We propose a spatially detailed cost-minimizing model for coal and agricultural production in a region under constraints on land and water availability. We apply the model to the case study of Shanxi province, China. We show how such an integrated optimization, which takes maximum advantage of the spatial heterogeneity in resource abundance, could help resolve the conflicts around the water–food–energy (WFE nexus and assist in its management. We quantify the production-possibility frontiers under different water-availability scenarios and demonstrate that in water-scarce regions, like Shanxi, the production capacity and corresponding production solutions are highly sensitive to water constraints. The shadow prices estimated in the model could be the basis for intelligent differentiated water pricing, not only to enable the water-resource transfer between agriculture and the coal industry, and across regions, but also to achieve cost-effective WFE management.

  4. Estimation of fluoride levels in various commercially available carbonated soft drinks in Chandigarh city, India

    Directory of Open Access Journals (Sweden)

    Mohit Bansal

    2015-01-01

    Full Text Available Introduction: Fluoride has a preventive action on dental caries. However, Excessive ingestion of fluoride from different sources can lead to the development of dental fluorosis. Aim: To estimate fluoride levels in various commercially available carbonated soft drinks available in Chandigarh city. Materials and Methods: Twelve different brands of commercially available soft drinks were purchased from three different places and divided into three groups. Fluoride levels were estimated using fluoride test strips Quantofix 37211 Fluka; Sigma-Aldrich. Results: Fluoride levels ranged from 0.12 to 0.42 mg/dl F with the maximum level in Thumbs up and least in Diet Pepsi. Conclusion: The levels of fluoride varied in various carbonated soft drinks analyzed. This could contribute significantly to the total fluoride intake from all sources and thus be an important risk factor for the development of dental fluorosis.

  5. A carbon-carbon panel design concept for the inboard limiter of the Compact Ignition Tokamak (CIT)

    International Nuclear Information System (INIS)

    Mantz, H.C.; Bowers, D.A.; Williams, F.R.; Witten, M.A.

    1989-01-01

    The inboard limiter of the Compact Ignition Tokamak (CIT) must protect the vacuum vessel from the plasma energy. This limiter region must withstand nominal heat fluxes in excess of 10 MW/m 2 and in addition it must be designed to be remotely maintained. Carbon-carbon composite material was selected over bulk graphite materials for the limiter design because of its ability to meet the thermal and structural requirements. The structural design concept consists of carbon-carbon composite panels attached to the vacuum vessel by a hinged rod/retainer concept. Results of the preliminary design study to define this inboard limiter are presented. The design concept is described along with the analyses of the thermal and structural response during nominal plasma operation and during plasma disruption events. 2 refs., 8 figs

  6. Life Prediction on a T700 Carbon Fiber Reinforced Cylinder with Limited Accelerated Life Testing Data

    Directory of Open Access Journals (Sweden)

    Ma Xiaobing

    2015-01-01

    Full Text Available An accelerated life testing investigation was conducted on a composite cylinder that consists of aluminum alloy and T700 carbon fiber. The ultimate failure stress predictions of cylinders were obtained by the mixing rule and verified by the blasting static pressure method. Based on the stress prediction of cylinder under working conditions, the constant stress accelerated life test of the cylinder was designed. However, the failure data cannot be sufficiently obtained by the accelerated life test due to the time limitation. Therefore, most of the data presented to be high censored in high stress level and zero-failure data in low stress level. When using the traditional method for rupture life prediction, the results showed to be of lower confidence. In this study, the consistency of failure mechanism for carbon fiber and cylinder was analyzed firstly. According to the analysis result, the statistical test information of carbon fiber could be utilized for the accelerated model constitution. Then, rupture life prediction method for cylinder was proposed based on the accelerated life test data and carbon fiber test data. In this way, the life prediction accuracy of cylinder could be improved obviously, and the results showed that the accuracy of this method increased by 35%.

  7. Diagnosing phosphorus limitations in natural terrestrial ecosystems in carbon cycle models

    Science.gov (United States)

    Sun, Yan; Peng, Shushi; Goll, Daniel S.; Ciais, Philippe; Guenet, Bertrand; Guimberteau, Matthieu; Hinsinger, Philippe; Janssens, Ivan A.; Peñuelas, Josep; Piao, Shilong; Poulter, Benjamin; Violette, Aurélie; Yang, Xiaojuan; Yin, Yi; Zeng, Hui

    2017-07-01

    Most of the Earth System Models (ESMs) project increases in net primary productivity (NPP) and terrestrial carbon (C) storage during the 21st century. Despite empirical evidence that limited availability of phosphorus (P) may limit the response of NPP to increasing atmospheric CO2, none of the ESMs used in the previous Intergovernmental Panel on Climate Change assessment accounted for P limitation. We diagnosed from ESM simulations the amount of P need to support increases in carbon uptake by natural ecosystems using two approaches: the demand derived from (1) changes in C stocks and (2) changes in NPP. The C stock-based additional P demand was estimated to range between -31 and 193 Tg P and between -89 and 262 Tg P for Representative Concentration Pathway (RCP) 2.6 and RCP8.5, respectively, with negative values indicating a P surplus. The NPP-based demand, which takes ecosystem P recycling into account, results in a significantly higher P demand of 648-1606 Tg P for RCP2.6 and 924-2110 Tg P for RCP8.5. We found that the P demand is sensitive to the turnover of P in decomposing plant material, explaining the large differences between the NPP-based demand and C stock-based demand. The discrepancy between diagnosed P demand and actual P availability (potential P deficit) depends mainly on the assumptions about availability of the different soil P forms. Overall, future P limitation strongly depends on both soil P availability and P recycling on ecosystem scale.

  8. Quantifying Fast and Slow Responses of Terrestrial Carbon Exchange across a Water Availability Gradient in North American Flux Sites

    Science.gov (United States)

    Biederman, J. A.; Scott, R. L.; Goulden, M.

    2014-12-01

    Climate change is predicted to increase the frequency and severity of water limitation, altering terrestrial ecosystems and their carbon exchange with the atmosphere. Here we compare site-level temporal sensitivity of annual carbon fluxes to interannual variations in water availability against cross-site spatial patterns over a network of 19 eddy covariance flux sites. This network represents one order of magnitude in mean annual productivity and includes western North American desert shrublands and grasslands, savannahs, woodlands, and forests with continuous records of 4 to 12 years. Our analysis reveals site-specific patterns not identifiable in prior syntheses that pooled sites. We interpret temporal variability as an indicator of ecosystem response to annual water availability due to fast-changing factors such as leaf stomatal response and microbial activity, while cross-site spatial patterns are used to infer ecosystem adjustment to climatic water availability through slow-changing factors such as plant community and organic carbon pools. Using variance decomposition, we directly quantify how terrestrial carbon balance depends on slow- and fast-changing components of gross ecosystem production (GEP) and total ecosystem respiration (TER). Slow factors explain the majority of variance in annual net ecosystem production (NEP) across the dataset, and their relative importance is greater at wetter, forest sites than desert ecosystems. Site-specific offsets from spatial patterns of GEP and TER explain one third of NEP variance, likely due to slow-changing factors not directly linked to water, such as disturbance. TER and GEP are correlated across sites as previously shown, but our site-level analysis reveals surprisingly consistent linear relationships between these fluxes in deserts and savannahs, indicating fast coupling of TER and GEP in more arid ecosystems. Based on the uncertainty associated with slow and fast factors, we suggest a framework for improved

  9. The Limitation Amount of Available Potassium for Wheat in a Loess Soil

    Directory of Open Access Journals (Sweden)

    M. Vafakhah

    2014-04-01

    Full Text Available The objective of this study was determining the most limiting plant growth factor in the wheat root zone dominated by illite in clay fraction and a high specific surface with ample ammonium acetate extractible potassium. A completely randomized block design with 4 replicates was used in Seyed Miran Research Farm (Gorgan during 2009-2010 growing season. Treatments were mineral fertilizers (to achieve different levels of yields, gypsum (1000 Kg/ha calcium, calcium chloride (1000 Kg ha-1 Ca, urea (93 Kg ha-1 N and potassium chloride (105 Kg ha-1 K combined, gypsum (1000 Kg ha-1 Ca and potassium chloride (105 Kg ha-1 K combined, calcium chloride (1000 Kg ha-1 Ca and potassium chloride (105 Kg ha-1 K combined and control. Wheat cultivar (N-80-19 was planted in experimental site at 2009/12/9. The results showed that potassium is the most limiting plant growth factor in the site of the experiment. Electric diffuse double layer is expected to be truncated with a high specific surface soil in this area minimizing the soil solution-diffuse double layer interface for rapid potassium diffusion. The highest yield grain and straw with urea and potassium chloride showed a greater effect on plant and soil potassium concentrations. A greater potassium diffusion rate may be achieved as a result of greater concentration gradients between the exchange sites and soil solution by potassium fertilization and more potassium excess. Ammonium from urea diminished potassium fixation with illite and increased potassium root uptake.

  10. Dilution limits dissolved organic carbon utilization in the deep ocean

    KAUST Repository

    Arrieta, Jesus

    2015-03-19

    Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

  11. Dilution limits dissolved organic carbon utilization in the deep ocean

    KAUST Repository

    Arrieta, J M; Mayol, Eva; Hansman, Roberta L.; Herndl, Gerhard J.; Dittmar, Thorsten; Duarte, Carlos M.

    2015-01-01

    Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

  12. Characterization of redeposited carbon layers on TEXTOR limiter by Laser Raman spectroscopy

    International Nuclear Information System (INIS)

    Egashira, K.; Tanabe, T.; Yoshida, M.; Nakazato, H.; Philipps, V.; Brezinsek, S.; Kreter, A.

    2011-01-01

    Highlights: ► Laser Raman technique has applied to analyze the deposited carbon layers on TEXTOR test limiters of C and W. ► The carbon deposited layers showed the Raman spectra composed of G-peak and D-peak. ► For W limiter, hydrogen concentrations in the deposited carbon layers and their thicknesses correlated to the two peaks. ► The Laser Raman spectroscopy is a promising tool for in situ analysis of carbon redeposit layers on plasma facing W materials. - Abstract: Laser Raman spectroscopy is quite sensitive to detect the changes of graphite structure. In this study, the Laser Raman technique was applied to analyze the deposited carbon layers on TEXTOR test limiters of carbon (C) and tungsten (W) produced by intentional carbon deposition experiments by methane gas puffing. The carbon deposited layers showed the Raman spectra composed of two broad peaks, G-peak and D-peak, centered at around 1580 and 1355 cm −1 respectively. For W limiter, the G-peak position and the integrated intensity of the two peaks well correlate to hydrogen concentrations in the deposited carbon layers and their thicknesses, respectively. Hence Laser Raman spectroscopy is a promising tool for the in situ analysis of carbon redeposit layers on plasma facing W materials and probably on Be materials.

  13. Determining the availability of phosphate and glucose for bacteria in P-limited mesocosms of NW Mediterranean surface waters

    Czech Academy of Sciences Publication Activity Database

    Tanaka, T.; Thingstad, T. F.; Gasol, J.M.; Cardelús, C.; Jezbera, Jan; Sala, M.M.; Šimek, Karel; Unrein, F.

    2009-01-01

    Roč. 56, č. 1 (2009), s. 81-91 ISSN 0948-3055 R&D Projects: GA ČR(CZ) GA206/08/0015 Institutional research plan: CEZ:AV0Z60170517 Keywords : microbial food -web * dissolved organic -carbon * nutrient limitation * bacterioplankton growth * heterotrophic bacteria Subject RIV: EE - Microbiology, Virology Impact factor: 1.743, year: 2009

  14. Increasingly, Data Availability Limits Model Predictive Capacity: the Western Lake Erie Basin, a Case Study

    Science.gov (United States)

    Behrman, K. D.; Johnson, M. V. V.; Atwood, J. D.; Norfleet, M. L.

    2016-12-01

    Recent algal blooms in Western Lake Erie Basin (WLEB) have renewed scientific community's interest in developing process based models to better understand and predict the drivers of eutrophic conditions in the lake. At the same time, in order to prevent future blooms, farmers, local communities and policy makers are interested in developing spatially explicit nutrient and sediment management plans at various scales, from field to watershed. These interests have fueled several modeling exercises intended to locate "hotspots" in the basin where targeted adoption of additional agricultural conservation practices could provide the most benefit to water quality. The models have also been used to simulate various scenarios representing potential agricultural solutions. The Soil and Water Assessment Tool (SWAT) and its sister model, the Agricultural Policy Environmental eXtender (APEX), have been used to simulate hydrology of interacting land uses in thousands of scientific studies around the world. High performance computing allows SWAT and APEX users to continue to improve and refine the model specificity to make predictions at small-spatial scales. Consequently, data inputs and calibration/validation data are now becoming the limiting factor to model performance. Water quality data for the tributaries and rivers that flow through WLEB is spatially and temporally limited. Land management data, including conservation practice and nutrient management data, are not publicly available at fine spatial and temporal scales. Here we show the data uncertainties associated with modeling WLEB croplands at a relatively large spatial scale (HUC-4) using site management data from over 1,000 farms collected by the Conservation Effects Assessment Project (CEAP). The error associated with downscaling this data to the HUC-8 and HUC-12 scale is shown. Simulations of spatially explicit dynamics can be very informative, but care must be taken when policy decisions are made based on models

  15. Limitations of carbon footprint as indicator of environmental sustainability.

    Science.gov (United States)

    Laurent, Alexis; Olsen, Stig I; Hauschild, Michael Z

    2012-04-03

    Greenhouse gas accountings, commonly referred to with the popular term carbon footprints (CFP), are a widely used metric of climate change impacts and the main focus of many sustainability policies among companies and authorities. However, environmental sustainability concerns not just climate change but also other environmental problems, like chemical pollution or depletion of natural resources, and the focus on CFP brings the risk of problem shifting when reductions in CFP are obtained at the expense of increase in other environmental impacts. But how real is this risk? Here, we model and analyze the life cycle impacts from about 4000 different products, technologies, and services taken from several sectors, including energy generation, transportation, material production, infrastructure, and waste management. By investigating the correlations between the CFP and 13 other impact scores, we show that some environmental impacts, notably those related to emissions of toxic substances, often do not covary with climate change impacts. In such situations, carbon footprint is a poor representative of the environmental burden of products, and environmental management focused exclusively on CFP runs the risk of inadvertently shifting the problem to other environmental impacts when products are optimized to become more "green". These findings call for the use of more broadly encompassing tools to assess and manage environmental sustainability.

  16. Carbon availability affects diurnally controlled processes and cell morphology of Cyanothece 51142.

    Directory of Open Access Journals (Sweden)

    Jana Stöckel

    Full Text Available Cyanobacteria are oxygenic photoautotrophs notable for their ability to utilize atmospheric CO2 as the major source of carbon. The prospect of using cyanobacteria to convert solar energy and high concentrations of CO2 efficiently into biomass and renewable energy sources has sparked substantial interest in using flue gas from coal-burning power plants as a source of inorganic carbon. However, in order to guide further advances in this area, a better understanding of the metabolic changes that occur under conditions of high CO2 is needed. To determine the effect of high CO2 on cell physiology and growth, we analyzed the global transcriptional changes in the unicellular diazotrophic cyanobacterium Cyanothece 51142 grown in 8% CO2-enriched air. We found a concerted response of genes related to photosynthesis, carbon metabolism, respiration, nitrogen fixation, ribosome biosynthesis, and the synthesis of nucleotides and structural cell wall polysaccharides. The overall response to 8% CO2 in Cyanothece 51142 involves different strategies, to compensate for the high C/N ratio during both phases of the diurnal cycle. Our analyses show that high CO2 conditions trigger the production of carbon-rich compounds and stimulate processes such as respiration and nitrogen fixation. In addition, we observed that high levels of CO2 affect fundamental cellular processes such as cell growth and dramatically alter the intracellular morphology. This study provides novel insights on how diurnal and developmental rhythms are integrated to facilitate adaptation to high CO2 in Cyanothece 51142.

  17. Cold-workability limits for carbon and alloy steels

    Science.gov (United States)

    El-Domiaty, A.

    1999-04-01

    In metalforming, the success in accomplishing the required deformation without failure of the forming tools or cracking of the work material represents the major concern for manufacture and design engineers. The degree of deformation that can be achieved in a particular metalworking process without creating an undesirable condition is defined as workability. In the present work, an experimental investigation was carried out to determine the cold-workability limits for five different types of steel: AISI 1018, 1045, 1078, 4140, and 4340. The upset (compression) test was used to determine the workability limit for each type. The upset dies and specimen geometries were designed to give different strain paths covering the range from homogeneous deformation (ɛz/ɛθ=-2.0) to close to plane-strain condition (ɛz/ɛθ=0.0). Grid pattern was printed on the specimen surface in order to measure the axial and hoop strain components during deformation. Specific elements were selected on the specimen surface, and their strain paths were determined. Each strain path was terminated once surface cracking had been observed. The ends of the strain paths, at which macrocracks were observed, were connected to obtain the workability limit on the forming-limit diagram. The workability limit of AISI 1018 is the highest among the other types of steel.

  18. Limitations of Carbon Footprint as Indicator of Environmental Sustainability

    DEFF Research Database (Denmark)

    Laurent, Alexis; Olsen, Stig I.; Hauschild, Michael Z.

    2012-01-01

    change but also other environmental problems, like chemical pollution or depletion of natural resources, and the focus on CFP brings the risk of problem shifting when reductions in CFP are obtained at the expense of increase in other environmental impacts. But how real is this risk? Here, we model...... runs the risk of inadvertently shifting the problem to other environmental impacts when products are optimized to become more “green”. These findings call for the use of more broadly encompassing tools to assess and manage environmental sustainability.......Greenhouse gas accountings, commonly referred to with the popular term carbon footprints (CFP), are a widely used metric of climate change impacts and the main focus of many sustainability policies among companies and authorities. However, environmental sustainability concerns not just climate...

  19. Ecohydrology of agroecosystems: probabilistic description of yield reduction risk under limited water availability

    Science.gov (United States)

    Vico, Giulia; Porporato, Amilcare

    2013-04-01

    Supplemental irrigation represents one of the main strategies to mitigate the effects of climate variability and stabilize yields. Irrigated agriculture currently provides 40% of food production and its relevance is expected to further increase in the near future, in face of the projected alterations of rainfall patterns and increase in food, fiber, and biofuel demand. Because of the significant investments and water requirements involved in irrigation, strategic choices are needed to preserve productivity and profitability, while maintaining a sustainable water management - a nontrivial task given the unpredictability of the rainfall forcing. To facilitate decision making under uncertainty, a widely applicable probabilistic framework is proposed. The occurrence of rainfall events and irrigation applications are linked probabilistically to crop development during the growing season and yields at harvest. Based on these linkages, the probability density function of yields and corresponding probability density function of required irrigation volumes, as well as the probability density function of yields under the most common case of limited water availability are obtained analytically, as a function of irrigation strategy, climate, soil and crop parameters. The full probabilistic description of the frequency of occurrence of yields and water requirements is a crucial tool for decision making under uncertainty, e.g., via expected utility analysis. Furthermore, the knowledge of the probability density function of yield allows us to quantify the yield reduction hydrologic risk. Two risk indices are defined and quantified: the long-term risk index, suitable for long-term irrigation strategy assessment and investment planning, and the real-time risk index, providing a rigorous probabilistic quantification of the emergence of drought conditions during a single growing season in an agricultural setting. Our approach employs relatively few parameters and is thus easily and

  20. Electro-deposition of Pd on carbon paper and Ni foam via surface limited redox-replacement reaction for oxygen reduction reaction

    CSIR Research Space (South Africa)

    Modibedi, RM

    2014-05-01

    Full Text Available Pd nanostructured catalysts were electrodeposited by surface-limited redox replacement reactions usingthe electrochemical atomic layer deposition technique. Carbon paper and Ni foam were used as substratesfor the electrodeposition of the metal...

  1. Response to Comment on "Dilution limits dissolved organic carbon utilization in the deep ocean"

    KAUST Repository

    Arrieta, J M; Mayol, E.; Hansman, R. L.; Herndl, G. J.; Dittmar, T.; Duarte, Carlos M.

    2015-01-01

    Our recent finding that dilution limits dissolved organic carbon (DOC) utilization in the deep ocean has been criticized based on the common misconception that lability equates to rapid and complete utilization. Even when considering

  2. Quantification of carbon and phosphorus co-limitation in bacterioplankton: new insights on an old topic.

    Directory of Open Access Journals (Sweden)

    Irene Dorado-García

    Full Text Available Because the nature of the main resource that limits bacterioplankton (e.g. organic carbon [C] or phosphorus [P] has biogeochemical implications concerning organic C accumulation in freshwater ecosystems, empirical knowledge is needed concerning how bacteria respond to these two resources, available alone or together. We performed field experiments of resource manipulation (2×2 factorial design, with the addition of C, P, or both combined in two Mediterranean freshwater ecosystems with contrasting trophic states (oligotrophy vs. eutrophy and trophic natures (autotrophy vs. heterotrophy, measured as gross primary production:respiration ratio. Overall, the two resources synergistically co-limited bacterioplankton, i.e. the magnitude of the response of bacterial production and abundance to the two resources combined was higher than the additive response in both ecosystems. However, bacteria also responded positively to single P and C additions in the eutrophic ecosystem, but not to single C in the oligotrophic one, consistent with the value of the ratio between bacterial C demand and algal C supply. Accordingly, the trophic nature rather than the trophic state of the ecosystems proves to be a key feature determining the expected types of resource co-limitation of bacteria, as summarized in a proposed theoretical framework. The actual types of co-limitation shifted over time and partially deviated (a lesser degree of synergism from the theoretical expectations, particularly in the eutrophic ecosystem. These deviations may be explained by extrinsic ecological forces to physiological limitations of bacteria, such as predation, whose role in our experiments is supported by the relationship between the dynamics of bacteria and bacterivores tested by SEMs (structural equation models. Our study, in line with the increasingly recognized role of freshwater ecosystems in the global C cycle, suggests that further attention should be focussed on the biotic

  3. Efficiency Limits of Solar Energy Harvesting via Internal Photoemission in Carbon Materials

    Directory of Open Access Journals (Sweden)

    Svetlana V. Boriskina

    2018-02-01

    Full Text Available We describe strategies to estimate the upper limits of the efficiency of photon energy harvesting via hot electron extraction from gapless absorbers. Gapless materials such as noble metals can be used for harvesting the whole solar spectrum, including visible and near-infrared light. The energy of photo-generated non-equilibrium or ‘hot’ charge carriers can be harvested before they thermalize with the crystal lattice via the process of their internal photo-emission (IPE through the rectifying Schottky junction with a semiconductor. However, the low efficiency and the high cost of noble metals necessitates the search for cheaper abundant alternative materials, and we show here that carbon can serve as a promising IPE material candidate. We compare the upper limits of performance of IPE photon energy-harvesting platforms, which incorporate either gold or carbon as the photoactive material where hot electrons are generated. Through a combination of density functional theory, joint electron density of states calculations, and Schottky diode efficiency modeling, we show that the material electron band structure imposes a strict upper limit on the achievable efficiency of the IPE devices. Our calculations reveal that graphite is a good material candidate for the IPE absorber for harvesting visible and near-infrared photons. Graphite electron density of states yields a sizeable population of hot electrons with energies high enough to be collected across the potential barrier. We also discuss the mechanisms that prevent the IPE device efficiency from reaching the upper limits imposed by their material electron band structures. The proposed approach is general and allows for efficient pre-screening of materials for their potential use in IPE energy converters and photodetectors within application-specific spectral windows.

  4. The Influence of Leaf Fall and Organic Carbon Availability on Nitrogen Cycling in a Headwater Stream

    Science.gov (United States)

    Thomas, S. A.; Kristin, A.; Doyle, B.; Goodale, C. L.; Gurwick, N. P.; Lepak, J.; Kulkari, M.; McIntyre, P.; McCalley, C.; Raciti, S.; Simkin, S.; Warren, D.; Weiss, M.

    2005-05-01

    The study of allochthonous carbon has a long and distinguished history in stream ecology. Despite this legacy, relatively little is known regarding the influence of leaf litter on nutrient dynamics. We conducted 15N-NO3 tracer additions to a headwater stream in upstate New York before and after autumn leaf fall to assess the influence of leaf litter on nitrogen spiraling. In addition, we amended the stream with labile dissolved organic carbon (as acetate) midway through each experiment to examine whether organic carbon availability differentially stimulated nitrogen cycling. Leaf standing stocks increased from 53 to 175 g dry mass m-2 and discharge more than tripled (6 to 20 L s-1) between the pre- and post-leaf fall period. In contrast, nitrate concentration fell from approximately 50 to less then 10 ug L-1. Despite higher discharge, uptake length was shorter following leaf fall under both ambient (250 and 72 m, respectively) and DOC amended (125 and 45 m) conditions. Uptake velocity increased dramatically following leaf fall, despite a slight decline in the areal uptake rate. Dissolved N2 gas samples were also collected to estimate denitrification rates under each experimental condition. The temporal extent of increased nitrogen retention will also be explored.

  5. Shrubland carbon sink depends upon winter water availability in the warm deserts of North America

    Science.gov (United States)

    Biederman, Joel A.; Scott, Russell L.; John A. Arnone,; Jasoni, Richard L.; Litvak, Marcy E.; Moreo, Michael T.; Papuga, Shirley A.; Ponce-Campos, Guillermo E.; Schreiner-McGraw, Adam P.; Vivoni, Enrique R.

    2018-01-01

    Global-scale studies suggest that dryland ecosystems dominate an increasing trend in the magnitude and interannual variability of the land CO2 sink. However, such model-based analyses are poorly constrained by measured CO2 exchange in open shrublands, which is the most common global land cover type, covering ∼14% of Earth’s surface. Here we evaluate how the amount and seasonal timing of water availability regulate CO2 exchange between shrublands and the atmosphere. We use eddy covariance data from six US sites across the three warm deserts of North America with observed ranges in annual precipitation of ∼100–400mm, annual temperatures of 13–18°C, and records of 2–8 years (33 site-years in total). The Chihuahuan, Sonoran and Mojave Deserts present gradients in both mean annual precipitation and its seasonal distribution between the wet-winter Mojave Desert and the wet-summer Chihuahuan Desert. We found that due to hydrologic losses during the wettest summers in the Sonoran and Chihuahuan Deserts, evapotranspiration (ET) was a better metric than precipitation of water available to drive dryland CO2 exchange. In contrast with recent synthesis studies across diverse dryland biomes, we found that NEP could not be directly predicted from ET due to wintertime decoupling of the relationship between ecosystem respiration (Reco) and gross ecosystem productivity (GEP). Ecosystem water use efficiency (WUE=GEP/ET) did not differ between winter and summer. Carbon use efficiency (CUE=NEP/GEP), however, was greater in winter because Reco returned a smaller fraction of carbon to the atmosphere (23% of GEP) than in summer (77%). Combining the water-carbon relations found here with historical precipitation since 1980, we estimate that lower average winter precipitation during the 21st century reduced the net carbon sink of the three deserts by an average of 6.8TgC yr1. Our results highlight that winter precipitation is critical to the annual carbon balance of these

  6. Critical assessment of the available technologies for sanitation of contaminated soil and their limits of application

    International Nuclear Information System (INIS)

    Nussbaumer, M.; Glaeser, E.

    1993-01-01

    Sanitation of polluted land comprises safety measures and soil purification measures. Soil purification can take place either in situ, or on-site or off-site after digging up the contaminated soil. In-situ processes are soil deaeration, groundwater purification and biological methods. Soil deaeration is suited for volatile pollutants in the unsaturated zone of loose soils, while groundwater purification is commonly applied for water-soluble pollutants in the saturated zone of soils with a high k f value. On-site or off-site purification of contaminated soils can take place by thermal processes, by soil washing, by microorganisms, or by physical processes. Thermal processes have the widest range of applications; they are suited for most soils polluted with mostly organic pollutants, and the residual contamination is lowest. Soil washing is limited to sandy and noncohesive soils and for emulsifiable or elutable pollutants. Biological on-site and off-line methods are limited to biodegradable pollutants which are not in phase. Loosening agents may be added in order to overcome geotechnical limitations. Physical purification of soils is limited to specific applications e.g. removal of volatile hydrocarbons. (orig.) [de

  7. Mobile carbohydrates in Himalayan treeline trees I. Evidence for carbon gain limitation but not for growth limitation.

    Science.gov (United States)

    Li, Mai-He; Xiao, Wen-Fa; Wang, San-Gen; Cheng, Gen-Wei; Cherubini, Paolo; Cai, Xaio-Hu; Liu, Xing-Liang; Wang, Xiao-Dan; Zhu, Wan-Ze

    2008-08-01

    To test whether the altitudinal distribution of trees is determined by a carbon shortage or an insufficient sugar fraction (sugar:starch ratio) in treeline trees, we studied the status of nonstructural carbohydrates (NSC) and their components (total soluble sugars and starch) in Abies fabri (Mast.) Craib and Picea balfouriana var. hirtella Rehd. et Wils. trees along three elevational gradients, ranging from lower elevations to the alpine treeline, on the eastern edge of the Tibetan Plateau. For comparison, we investigated a low-altitude species (Tsuga yunnanensis (Franch.) Pritz.) which served as a warm-climate reference because it is distributed in closed montane forests below 3100 m a.s.l. in the study area. The carbon status of T. yunnanensis responded to altitude differently from that of the treeline species. At the species level, total NSC was not consistently more abundant in treeline trees than in trees of the same species growing at lower elevations. Thus there was no consistent evidence for carbon limitation of growth in treeline trees. For the three treeline species studied (P. balfouriana and A. fabri in the Kang-Ding Valley and A. fabri in the Mo-Xi Valley), winter NSC concentrations in treeline trees were significantly lower than in lower-elevation trees of the same species, suggesting that, in winter, carbon is limited in treeline trees. However, in no case was there total overwinter depletion of NSC or its components in treeline trees. Treeline and low-altitude species had similar sugar:starch ratios of about three at their upper-elevational limits in April. We conclude that survival and growth of trees at the elevational or latitudinal climate limit depend not only on NSC concentration in perennial tissues, but also on the maintenance of an overwintering sugar:starch ratio greater than three.

  8. 77 FR 8258 - Availability of ICCVAM Evaluation Report and Recommendations on the Usefulness and Limitations of...

    Science.gov (United States)

    2012-02-14

    ... and antagonist activity. This use is based on an evaluation of results from an international... activity. This use is based on an evaluation of available validation study data and corresponding accuracy... DEPARTMENT OF HEALTH AND HUMAN SERVICES Availability of ICCVAM Evaluation Report and...

  9. Potassium nutrition and water availability affect phloem transport of photosynthetic carbon in eucalypt trees

    Science.gov (United States)

    Epron, Daniel; Cabral, Osvaldo; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo; Trivelin, Paulo; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

    2015-04-01

    Potassium fertilisation strongly affects growth and carbon partitioning of eucalypt on tropical soil that are strongly weathered. In addition, potassium fertilization could be of great interest in mitigating the adverse consequences of drought in planted forests, as foliar K concentrations influence osmotic adjustment, stomatal regulation and phloem loading. Phloem is the main pathway for transferring photosynthate from source leaves to sink organs, thus controlling growth partitioning among the different tree compartments. But little is known about the effect of potassium nutrition on phloem transport of photosynthetic carbon and on the interaction between K nutrition and water availability. In situ 13C pulse labelling was conducted on tropical eucalypt trees (Eucalyptus grandis L.) grown in a trial plantation with plots in which 37% of throughfall were excluded (about 500 mm/yr) using home-made transparent gutters (-W) or not (+W) and plots that received 0.45 mol K m-2 applied as KCl three months after planting (+K) or not (-K). Three trees were labelled in each of the four treatments (+K+W, +K-W, -K+W and -K-W). Trees were labelled for one hour by injecting pure 13CO2 in a 27 m3 whole crown chamber. We estimated the velocity of carbon transfer in the trunk by comparing time lags between the uptake of 13CO2 and its recovery in trunk CO2 efflux recorded by off axis integrated cavity output spectroscopy (Los Gatos Research) in two chambers per tree, one just under the crown and one at the base of the trunk. We analyzed the dynamics of the label recovered in the foliage and in the phloem sap by analysing carbon isotope composition of bulk leaf organic matter and phloem extracts using an isotope ratio mass spectrometer. The velocity of carbon transfer in the trunk and the initial rate 13C disappearance from the foliage were much higher in +K trees than in -K trees with no significant effect of rainfall. The volumetric flow of phloem, roughly estimated by multiplying

  10. Limitations to postfire seedling establishment: The role of seeding technology, water availability, and invasive plant abundance

    Science.gov (United States)

    Jeremy J. James; Tony Svejcar

    2010-01-01

    Seeding rangeland following wildfire is a central tool managers use to stabilize soils and inhibit the spread of invasive plants. Rates of successful seeding on arid rangeland, however, are low. The objective of this study was to determine the degree to which water availability, invasive plant abundance, and seeding technology influence postfire seedling establishment...

  11. Does assimilate supply limit expansion in wheat grown in the field under low phosphorus availability

    NARCIS (Netherlands)

    Rodriguez, D.; Andrade, F.H.; Goudriaan, J.

    2000-01-01

    Under conditions of phosphorus deficiency, reductions in plant leaf area have been attributed to both direct effects of phosphorus (P) on the individual leaf expansion rate and a reduced availability of assimilates for leaf growth. Simulation techniques have been used to test the hypothesis of a

  12. Haematopoietic ESL-1 enables stem cell proliferation in the bone marrow by limiting TGFβ availability.

    Science.gov (United States)

    Leiva, Magdalena; Quintana, Juan A; Ligos, José M; Hidalgo, Andrés

    2016-01-08

    The life-long maintenance of haematopoietic stem and progenitor cells (HSPCs) critically relies on environmental signals produced by cells that constitute the haematopoietic niche. Here we report a cell-intrinsic mechanism whereby haematopoietic cells limit proliferation within the bone marrow, and show that this pathway is repressed by E-selectin ligand 1 (ESL-1). Mice deficient in ESL-1 display aberrant HSPC quiescence, expansion of the immature pool and reduction in niche size. Remarkably, the traits were transplantable and dominant when mutant and wild-type precursors coexisted in the same environment, but were independent of E-selectin, the vascular receptor for ESL-1. Instead, quiescence is generated by unrestrained production of the cytokine TGFβ by mutant HSPC, and in vivo or in vitro blockade of the cytokine completely restores the homeostatic properties of the haematopoietic niche. These findings reveal that haematopoietic cells, including the more primitive compartment, can actively shape their own environment.

  13. Nutrient and carbon availability influences on denitrification in the regulated Lower Colorado River, Austin

    Science.gov (United States)

    Spector, J.

    2016-12-01

    The Lower Colorado River in Austin, Texas receives nitrogen-rich runoff and treated wastewater effluent and is subject to periodic water releases from the Longhorn Dam, which cause fluctuations in groundwater stage downstream. This research examined groundwater denitrification at the Hornsby Bend riparian area (located approximately 24 km downstream of downtown Austin) and characterized how dam-induced hyporheic exchange affects denitrification rates. Conductivity, temperature, water level, and dissolved oxygen concentrations were measured continuously throughout flood pulses for six months using dataloggers installed in a transect of seven monitoring wells on the river bank. Hourly samples were collected using an autosampler in one monitoring well (MW-5) during various flood conditions during the six month monitoring period. Water samples were analyzed for total organic carbon, total nitrogen, anions (NO3- and NO2-), NH4+ concentrations, alkalinity, and specific ultraviolet absorbance (SUVA) to characterize dissolved organic matter. Following large flood events (up to 4 m of water level stage increase), average conductivity increased 300 µs/centimeter in MW-5 as the water level receded. Analysis of water samples indicated that NO3- reduction occurred as conductivity and alkalinity increased. In addition, NH4+ concentrations increased during high conductivity periods. Increased denitrification activity corresponded with high SUVA. High conductivity and alkalinity increase the availability of electron donors (HCO3- and CO32-) and enhances denitrification potential. Higher SUVA values indicate increased dissolved organic carbon aromaticity and corresponding NO3- reduction. Additionally, changes in dissolved organic matter lability indicate the residence times of possible reactive organic carbon in the riparian area. This study has implications for determining advantageous geochemical conditions for hyporheic zone denitrification following large flood events.

  14. Constraint-Based Modeling Highlights Cell Energy, Redox Status and α-Ketoglutarate Availability as Metabolic Drivers for Anthocyanin Accumulation in Grape Cells Under Nitrogen Limitation

    Directory of Open Access Journals (Sweden)

    Eric Soubeyrand

    2018-05-01

    Full Text Available Anthocyanin biosynthesis is regulated by environmental factors (such as light, temperature, and water availability and nutrient status (such as carbon, nitrogen, and phosphate nutrition. Previous reports show that low nitrogen availability strongly enhances anthocyanin accumulation in non carbon-limited plant organs or cell suspensions. It has been hypothesized that high carbon-to-nitrogen ratio would lead to an energy excess in plant cells, and that an increase in flavonoid pathway metabolic fluxes would act as an “energy escape valve,” helping plant cells to cope with energy and carbon excess. However, this hypothesis has never been tested directly. To this end, we used the grapevine Vitis vinifera L. cultivar Gamay Teinturier (syn. Gamay Freaux or Freaux Tintorier, VIVC #4382 cell suspension line as a model system to study the regulation of anthocyanin accumulation in response to nitrogen supply. The cells were sub-cultured in the presence of either control (25 mM or low (5 mM nitrate concentration. Targeted metabolomics and enzyme activity determinations were used to parametrize a constraint-based model describing both the central carbon and nitrogen metabolisms and the flavonoid (phenylpropanoid pathway connected by the energy (ATP and reducing power equivalents (NADPH and NADH cofactors. The flux analysis (2 flux maps generated, for control and low nitrogen in culture medium clearly showed that in low nitrogen-fed cells all the metabolic fluxes of central metabolism were decreased, whereas fluxes that consume energy and reducing power, were either increased (upper part of glycolysis, shikimate, and flavonoid pathway or maintained (pentose phosphate pathway. Also, fluxes of flavanone 3β-hydroxylase, flavonol synthase, and anthocyanidin synthase were strongly increased, advocating for a regulation of the flavonoid pathway by alpha-ketoglutarate levels. These results strongly support the hypothesis of anthocyanin biosynthesis acting as

  15. Commercially Available Activated Carbon Fiber Felt Enables Efficient Solar Steam Generation.

    Science.gov (United States)

    Li, Haoran; He, Yurong; Hu, Yanwei; Wang, Xinzhi

    2018-03-21

    Sun-driven steam generation is now possible and has the potential to help meet future energy needs. Current technologies often use solar condensers to increase solar irradiance. More recently, a technology for solar steam generation that uses heated surface water and low optical concentration is reported. In this work, a commercially available activated carbon fiber felt is used to generate steam efficiently under one sun illumination. The evaporation rate and solar conversion efficiency reach 1.22 kg m -2 h -1 and 79.4%, respectively. The local temperature of the evaporator with a floating activated carbon fiber felt reaches 48 °C. Apart from the high absorptivity (about 94%) of the material, the evaporation performance is enhanced thanks to the well-developed pores for improved water supply and steam escape and the low thermal conductivity, which enables reduced bulk water temperature increase. This study helps to find a promising material for solar steam generation using a water evaporator that can be produced economically (∼6 $/m 2 ) with long-term stability.

  16. Age, allocation and availability of nonstructural carbon in mature red maple trees.

    Science.gov (United States)

    Carbone, Mariah S; Czimczik, Claudia I; Keenan, Trevor F; Murakami, Paula F; Pederson, Neil; Schaberg, Paul G; Xu, Xiaomei; Richardson, Andrew D

    2013-12-01

    The allocation of nonstructural carbon (NSC) to growth, metabolism and storage remains poorly understood, but is critical for the prediction of stress tolerance and mortality. We used the radiocarbon ((14) C) 'bomb spike' as a tracer of substrate and age of carbon in stemwood NSC, CO2 emitted by stems, tree ring cellulose and stump sprouts regenerated following harvesting in mature red maple trees. We addressed the following questions: which factors influence the age of stemwood NSC?; to what extent is stored vs new NSC used for metabolism and growth?; and, is older, stored NSC available for use? The mean age of extracted stemwood NSC was 10 yr. More vigorous trees had both larger and younger stemwood NSC pools. NSC used to support metabolism (stem CO2 ) was 1-2 yr old in spring before leaves emerged, but reflected current-year photosynthetic products in late summer. The tree ring cellulose (14) C age was 0.9 yr older than direct ring counts. Stump sprouts were formed from NSC up to 17 yr old. Thus, younger NSC is preferentially used for growth and day-to-day metabolic demands. More recently stored NSC contributes to annual ring growth and metabolism in the dormant season, yet decade-old and older NSC is accessible for regrowth. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  17. Influence of substitutional atoms on the solubility limit of carbon in bcc iron

    International Nuclear Information System (INIS)

    Saitoh, Hajime; Ushioda, Kohsaku; Yoshinaga, Naoki; Yamada, Wataru

    2011-01-01

    The influence of substitutional atoms (Mn, Cr, Si, P, and Al) on the solubility limit of C in body-centered cubic iron in equilibrium with cementite was investigated in low-carbon steels at a temperature of 700 o C. The C solubility limit was determined from internal friction measurements combined with infrared analysis of C using a high-frequency combustion technique. Experiments clarified that Mn, Cr and Al hardly change the C solubility limit, whereas P and Si increase it.

  18. Gluten-Free Foods in Rural Maritime Provinces: Limited Availability, High Price, and Low Iron Content.

    Science.gov (United States)

    Jamieson, Jennifer A; Gougeon, Laura

    2017-12-01

    We investigated the price difference between gluten-free (GF) and gluten-containing (GC) foods available in rural Maritime stores. GF foods and comparable GC items were sampled through random visits to 21 grocery stores in nonurban areas of Nova Scotia, New Brunswick, and Prince Edward Island, Canada. Wilcoxon rank tests were conducted on price per 100 g of product, and on the price relative to iron content; 2226 GF foods (27.2% staple items, defined as breads, cereals, flours, and pastas) and 1625 GC foods were sampled, with an average ± SD of 66 ± 2.7 GF items per store in rural areas and 331 ± 12 in towns. The median price of GF items ($1.76/100 g) was more expensive than GC counterparts ($1.05/100 g) and iron density was approximately 50% less. GF staple foods were priced 5% higher in rural stores than in town stores. Although the variety of GF products available to consumers has improved, higher cost and lower nutrient density remain issues in nonurban Maritime regions. Dietitians working in nonurban areas should consider the relative high price, difficult access, and low iron density of key GF items, and work together with clients to find alternatives and enhance their food literacy.

  19. Carbon source from the toroidal pumped limiter during long discharge operation in Tore Supra

    International Nuclear Information System (INIS)

    Dufour, E.; Brosset, C.; Lowry, C.; Bucalossi, J.; Chappuis, P.; Corre, Y.; Desgranges, C.; Guirlet, R.; Gunn, J.; Loarer, T.; Mitteau, R.; Monier-Garbet, P.; Pegourie, B.; Reichle, R.; Thomas, P.; Tsitrone, E.; Hogan, J.; Roubin, P.; Martin, C.; Arnas, C.

    2005-01-01

    A better understanding of deuterium retention mechanisms requires the knowledge of carbon sources in Tore-Supra. The main source of carbon in the vacuum vessel during long discharges is the toroidal pumped limiter (TPL). This work is devoted to the experimental characterisation of the carbon source from the TPL surface during long discharges using a visible spectroscopy diagnostic. Moreover, we present an attempt to perform a carbon balance over a typical campaign and we discuss it with regards to the deuterium in-vessel inventory deduced from particle balance and the deuterium content of the deposited layers. The study shows that only a third of the estimated deuterium trapped in the vessel is trapped in the carbon deposits. Thus, in the present state of our knowledge and characterisation of the permanent retention, one has to search for mechanisms other than co-deposition to explain the deuterium retention in Tore Supra. (A.C.)

  20. Not sold here: limited access to legally available syringes at pharmacies in Tijuana, Mexico.

    Science.gov (United States)

    Pollini, Robin A; Rosen, Perth C; Gallardo, Manuel; Robles, Brenda; Brouwer, Kimberly C; Macalino, Grace E; Lozada, Remedios

    2011-05-24

    Sterile syringe access is a critical component of HIV prevention programs. Although retail pharmacies provide convenient outlets for syringe access, injection drug users (IDUs) may encounter barriers to syringe purchase even where purchase without a prescription is legal. We sought to obtain an objective measure of syringe access in Tijuana, Mexico, where IDUs report being denied or overcharged for syringes at pharmacies. Trained "mystery shoppers" attempted to buy a 1 cc insulin syringe according to a predetermined script at all retail pharmacies in three Tijuana neighborhoods. The same pharmacies were surveyed by telephone regarding their syringe sales policies. Data on purchase attempts were analyzed using basic statistics to obtain an objective measure of syringe access and compared with data on stated sales policies to ascertain consistency. Only 46 (28.4%) of 162 syringe purchase attempts were successful. Leading reasons for unsuccessful attempts were being told that the pharmacy didn't sell syringes (35.3%), there were no syringes in stock (31.0%), or a prescription was required (20.7%). Of 136 pharmacies also surveyed by telephone, a majority (88.2%) reported selling syringes but only one-third (32.5%) had a successful mystery shopper purchase; the majority of unsuccessful purchases were attributed to being told the pharmacy didn't sell syringes. There was similar discordance regarding prescription policies: 74 pharmacies said in the telephone survey that they did not require a prescription for syringes, yet 10 of these pharmacies asked the mystery shopper for a prescription. IDUs in Tijuana have limited access to syringes through retail pharmacies and policies and practices regarding syringe sales are inconsistent. Reasons for these restrictive and inconsistent practices must be identified and addressed to expand syringe access, reduce syringe sharing and prevent HIV transmission.

  1. Limited availability of psoriasis and phototherapy care: an analysis of advertisements.

    Science.gov (United States)

    Hancox, John G; Balkrishnan, Rajesh; Battle, Jamila; Housman, Tam Salam; Fleischer, Alan B; Feldman, Steven R

    2005-08-01

    Because the number of dermatologists remains stable, patients with medical dermatologic conditions such as psoriasis may find it increasingly difficult to access dermatological treatment. Measuring the competition in the marketing of dermatologic care may provide insight into the availability of dermatology services. The purpose of this study was to determine to what extent dermatologists are using the Yellow Pages to advertise to patients with psoriasis. We performed a quantitative and qualitative assessment of dermatologists' Yellow Pages advertisements in small cities and the ten largest metropolitan regions in the country. Per capita, more advertisements were found in smaller markets than larger markets and a higher percentage was descriptive rather than just a name, address and phone number. Cosmetic and surgical advertisements were more common than psoriasis ads in both markets. Cosmetic ads were more prevalent in larger markets. In all regions, psoriasis and psoriasis treatment ads were least common. These findings raise the concern that incentive structures in the United States healthcare system do not adequately support delivery of dermatologic care for psoriasis. Efforts to promote psoriasis care should be encouraged.

  2. Estimating brain connectivity when few data points are available: Perspectives and limitations.

    Science.gov (United States)

    Antonacci, Yuri; Toppi, Jlenia; Caschera, Stefano; Anzolin, Alessandra; Mattia, Donatella; Astolfi, Laura

    2017-07-01

    Methods based on the use of multivariate autoregressive modeling (MVAR) have proved to be an accurate and flexible tool for the estimation of brain functional connectivity. The multivariate approach, however, implies the use of a model whose complexity (in terms of number of parameters) increases quadratically with the number of signals included in the problem. This can often lead to an underdetermined problem and to the condition of multicollinearity. The aim of this paper is to introduce and test an approach based on Ridge Regression combined with a modified version of the statistics usually adopted for these methods, to broaden the estimation of brain connectivity to those conditions in which current methods fail, due to the lack of enough data points. We tested the performances of this new approach, in comparison with the classical approach based on ordinary least squares (OLS), by means of a simulation study implementing different ground-truth networks, under different network sizes and different levels of data points. Simulation results showed that the new approach provides better performances, in terms of accuracy of the parameters estimation and false positives/false negatives rates, in all conditions related to a low data points/model dimension ratio, and may thus be exploited to estimate and validate estimated patterns at single-trial level or when short time data segments are available.

  3. 40 CFR 432.73 - Effluent limitations attainable by the application of the best available technology economically...

    Science.gov (United States)

    2010-07-01

    ... application of the best available technology economically achievable (BAT). 432.73 Section 432.73 Protection... POULTRY PRODUCTS POINT SOURCE CATEGORY Sausage and Luncheon Meats Processors § 432.73 Effluent limitations attainable by the application of the best available technology economically achievable (BAT). Except as...

  4. Simulation of water-energy fluxes through small-scale reservoir systems under limited data availability

    Science.gov (United States)

    Papoulakos, Konstantinos; Pollakis, Giorgos; Moustakis, Yiannis; Markopoulos, Apostolis; Iliopoulou, Theano; Dimitriadis, Panayiotis; Koutsoyiannis, Demetris; Efstratiadis, Andreas

    2017-04-01

    Small islands are regarded as promising areas for developing hybrid water-energy systems that combine multiple sources of renewable energy with pumped-storage facilities. Essential element of such systems is the water storage component (reservoir), which implements both flow and energy regulations. Apparently, the representation of the overall water-energy management problem requires the simulation of the operation of the reservoir system, which in turn requires a faithful estimation of water inflows and demands of water and energy. Yet, in small-scale reservoir systems, this task in far from straightforward, since both the availability and accuracy of associated information is generally very poor. For, in contrast to large-scale reservoir systems, for which it is quite easy to find systematic and reliable hydrological data, in the case of small systems such data may be minor or even totally missing. The stochastic approach is the unique means to account for input data uncertainties within the combined water-energy management problem. Using as example the Livadi reservoir, which is the pumped storage component of the small Aegean island of Astypalaia, Greece, we provide a simulation framework, comprising: (a) a stochastic model for generating synthetic rainfall and temperature time series; (b) a stochastic rainfall-runoff model, whose parameters cannot be inferred through calibration and, thus, they are represented as correlated random variables; (c) a stochastic model for estimating water supply and irrigation demands, based on simulated temperature and soil moisture, and (d) a daily operation model of the reservoir system, providing stochastic forecasts of water and energy outflows. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students

  5. The production of cyanobacterial carbon under nitrogen-limited cultivation and its potential for nitrate removal.

    Science.gov (United States)

    Huang, Yingying; Li, Panpan; Chen, Guiqin; Peng, Lin; Chen, Xuechu

    2018-01-01

    Harmful cyanobacterial blooms (CyanoHABs) represent a serious threat to aquatic ecosystems. A beneficial use for these harmful microorganisms would be a promising resolution of this urgent issue. This study applied a simple method, nitrogen limitation, to cultivate cyanobacteria aimed at producing cyanobacterial carbon for denitrification. Under nitrogen-limited conditions, the common cyanobacterium, Microcystis, efficiently used nitrate, and had a higher intracellular C/N ratio. More importantly, organic carbons easily leached from its dry powder; these leachates were biodegradable and contained a larger amount of dissolved organic carbon (DOC) and carbohydrates, but a smaller amount of dissolved total nitrogen (DTN) and proteins. When applied to an anoxic system with a sediment-water interface, a significant increase of the specific NO X - -N removal rate was observed that was 14.2 times greater than that of the control. This study first suggests that nitrogen-limited cultivation is an efficient way to induce organic and carbohydrate accumulation in cyanobacteria, as well as a high C/N ratio, and that these cyanobacteria can act as a promising carbon source for denitrification. The results indicate that application as a carbon source is not only a new way to utilize cyanobacteria, but it also contributes to nitrogen removal in aquatic ecosystems, further limiting the proliferation of CyanoHABs. Copyright © 2017. Published by Elsevier Ltd.

  6. Effect of carbon limitation on photosynthetic electron transport in Nannochloropsis oculata.

    Science.gov (United States)

    Zavřel, Tomáš; Szabó, Milán; Tamburic, Bojan; Evenhuis, Christian; Kuzhiumparambil, Unnikrishnan; Literáková, Petra; Larkum, Anthony W D; Raven, John A; Červený, Jan; Ralph, Peter J

    2018-04-01

    This study describes the impacts of inorganic carbon limitation on the photosynthetic efficiency and operation of photosynthetic electron transport pathways in the biofuel-candidate microalga Nannochloropsis oculata. Using a combination of highly-controlled cultivation setup (photobioreactor), variable chlorophyll a fluorescence and transient spectroscopy methods (electrochromic shift (ECS) and P 700 redox kinetics), we showed that net photosynthesis and effective quantum yield of Photosystem II (PSII) decreased in N. oculata under carbon limitation. This was accompanied by a transient increase in total proton motive force and energy-dependent non-photochemical quenching as well as slightly elevated respiration. On the other hand, under carbon limitation the rapid increase in proton motive force (PMF, estimated from the total ECS signal) was also accompanied by reduced conductivity of ATP synthase to protons (estimated from the rate of ECS decay in dark after actinic illumination). This indicates that the slow operation of ATP synthase results in the transient build-up of PMF, which leads to the activation of fast energy dissipation mechanisms such as energy-dependent non-photochemical quenching. N. oculata also increased content of lipids under carbon limitation, which compensated for reduced NAPDH consumption during decreased CO 2 fixation. The integrated knowledge of the underlying energetic regulation of photosynthetic processes attained with a combination of biophysical methods may be used to identify photo-physiological signatures of the onset of carbon limitation in microalgal cultivation systems, as well as to potentially identify microalgal strains that can better acclimate to carbon limitation. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Carbon source-sink limitations differ between two species with contrasting growth strategies.

    Science.gov (United States)

    Burnett, Angela C; Rogers, Alistair; Rees, Mark; Osborne, Colin P

    2016-11-01

    Understanding how carbon source and sink strengths limit plant growth is a critical knowledge gap that hinders efforts to maximize crop yield. We investigated how differences in growth rate arise from source-sink limitations, using a model system comparing a fast-growing domesticated annual barley (Hordeum vulgare cv. NFC Tipple) with a slow-growing wild perennial relative (Hordeum bulbosum). Source strength was manipulated by growing plants at sub-ambient and elevated CO 2 concentrations ([CO 2 ]). Limitations on vegetative growth imposed by source and sink were diagnosed by measuring relative growth rate, developmental plasticity, photosynthesis and major carbon and nitrogen metabolite pools. Growth was sink limited in the annual but source limited in the perennial. RGR and carbon acquisition were higher in the annual, but photosynthesis responded weakly to elevated [CO 2 ] indicating that source strength was near maximal at current [CO 2 ]. In contrast, photosynthetic rate and sink development responded strongly to elevated [CO 2 ] in the perennial, indicating significant source limitation. Sink limitation was avoided in the perennial by high sink plasticity: a marked increase in tillering and root:shoot ratio at elevated [CO 2 ], and lower non-structural carbohydrate accumulation. Alleviating sink limitation during vegetative development could be important for maximizing growth of elite cereals under future elevated [CO 2 ]. © 2016 John Wiley & Sons Ltd.

  8. Evidence of different stoichiometries for the limiting carbonate complexes of lanthanides(3)

    International Nuclear Information System (INIS)

    Philippini, V.

    2007-12-01

    Two stoichiometries have been proposed by different laboratories to interpret measurements on the limiting carbonate complexes of An 3+ and Ln 3+ cations. The study of the solubility of double carbonates (AlkLn(CO 3 ) 2 ,xH 2 O) in concentrated carbonate solutions at room temperature and high ionic strengths has shown that on the one hand the lightest lanthanides (La and Nd) form Ln(CO 3 ) 4 5- whereas the heaviest (Eu and Dy) form Ln(CO 3 ) 3 3- in the studied chemical conditions, and on the other hand, that the kinetics of precipitation of double carbonates depends on the alkali metal and the lanthanide ions. The existence of two stoichiometries for the limiting carbonate complexes was confirmed by capillary electrophoresis hyphenated to an inductively coupled plasma mass spectrometer (CE-ICP-MS), used to extend the study to the whole series of lanthanides (except Ce, Pm and Yb). Two behaviours have been put forward comparing the electrophoretic mobilities: La to Tb form Ln(CO 3 ) 4 5- while Dy to Lu form Ln(CO 3 ) 3 3- . Measurements by time resolved laser fluorescence spectroscopy (TRLFS) on Eu(III) indicate small variations of the geometry of Eu(CO 3 ) 3 3- complex, specially with Cs + . Although analogies are currently used among the 4f-block trivalent elements, different aqueous speciations are evidenced in concentrated carbonate solutions across the lanthanide series. (author)

  9. Anaplerotic metabolism of Aspergillus nidulans and its effect on biomass synthesis in carbon limited chemostats

    Energy Technology Data Exchange (ETDEWEB)

    Bushell, M E; Bull, A T

    1981-01-01

    Anaplerotic fixation of carbon dioxide by the fungus Aspergillus nidulans when grown under carbon-limited conditions was mediated by pyruvate carboxylase and a phosphoenol pyruvate (PEP)-metabolising enzyme which has been tentatively designated as PEP carboxylase. The activities of both enzymes were growth rate dependent and measurements of H/sup 14/CO/sub 3/ incorporation by growing mycelium indicated that they were responsible for almost all the assimilated carbon dioxide. In carbon-limited chemostats, the maximum rate of bicarbonate assimilation occurred at a dilution rate of 0.11 h/sup -1/, equivalent to 1/2 ..mu..sub(max). The affinity of the pyruvate carboxylase for bicarbonate was twice of the PEP carboxylase under the conditions of growth used. The effect of changing the bicarbonate concentration in carbon-limited chemostats was substantial: increasing the HCO/sup -//sub 3/ concentration over the range 0.7-2.8 mM enhanced biomass synthesis by 22%. Over-shoots in bicarbonate assimilation and carboxylase activity occurred when steady state chemostat cultures were subjected to a step down in dilution rate.

  10. Seasonal Dynamics of Mobile Carbon Supply in Quercus aquifolioides at the Upper Elevational Limit

    Science.gov (United States)

    Zhu, Wan-Ze; Cao, Min; Wang, San-Gen; Xiao, Wen-Fan; Li, Mai-He

    2012-01-01

    Many studies have tried to explain the physiological mechanisms of the alpine treeline phenomenon, but the debate on the alpine treeline formation remains controversial due to opposite results from different studies. The present study explored the carbon-physiology of an alpine shrub species (Quercus aquifolioides) grown at its upper elevational limit compared to lower elevations, to test whether the elevational limit of alpine shrubs (treeline formation. PMID:22479567

  11. Availability, usage, and threats to freshwater resources on low carbonate islands in Micronesia

    Science.gov (United States)

    Taboroši, Danko; Jenson, John W.; Sánchez Collazo, Maricruz; Zega, Mojca

    2010-05-01

    Federated States of Micronesia (FSM) is an insular nation in the western Pacific. It consists of 4 high volcanic islands and 37 low carbonate units, mostly coral atolls. The high islands are relatively large, and are developing socioeconomic centers of the country, whereas low islands are small and remote outposts of traditional subsistence lifestyle. The latter are inhabited by a fifth of the nation's population of 107,000 people. Total land area of a typical low island is a fraction of a km2, yet may be home to hundreds of people, creating some of the highest population densities in the Pacific. The resultant extreme pressures on natural resources are exacerbated by severe weather hazards, especially typhoons and unusually high tides which have recently flooded some islands in entirety, damaging homes and food sources. Freshwater resources are particularly sensitive. Crowded low islands have some of the world's most unfavorable relationships between population density and freshwater availability. As there are no communal or municipal facilities and government operated infrastructure, people have only two sources of water available for consumption: rainwater and groundwater. Rain is captured by individual households' thatch or corrugated iron roofs and transferred by gutters to concrete or fiberglass tanks. It is used for drinking, cooking, and dishwashing, and depending on availability, for laundry and showering. Such arrangement are highly unreliable, because they depend on sufficient rainfall and islanders' ability to capture and store it. Some communities have actually run out of water in the past, as a result of prolonged droughts or typhoons' damage to the catchment systems. In addition, tropical climate and pervasive organic matter and microorganisms make the tanks' maintenance difficult, because even most conscientious cleaning cannot ensure that stored water remains potable. Stomach problems and more serious health complications are common. Groundwater

  12. Assessing groundwater availability in a folded carbonate aquifer through the development of a numerical model

    Science.gov (United States)

    Di Salvo, Cristina; Romano, Emanuele; Guyennon, Nicolas; Bruna Petrangeli, Anna; Preziosi, Elisabetta

    2015-04-01

    The study of aquifer systems from a quantitative point of view is fundamental for adopting water management plans aiming at preserving water resources and reducing environmental risks related to groundwater level and discharge changes. This is also what the European Union Water Framework Directive (WFD, 2000/60/EC) states, holding the development of numerical models as a key aspect for groundwater management. The objective of this research is to i) define a methodology for modeling a complex hydrogeological structure in a structurally folded carbonate area and ii) estimate the concurrent effects of exploitation and climate changes on groundwater availability through the implementation of a 3D groundwater flow model. This study concerns the Monte Coscerno karst aquifer located in the Apennine chain in Central Italy in the Nera River Valley.This aquifer, is planned to be exploited in the near future for water supply. Negative trends of precipitation in Central Italy have been reported in relation to global climate changes, which are expected to affect the availability of recharge to carbonate aquifers throughout the region . A great concern is the combined impact of climate change and groundwater exploitation, hence scenarios are needed taking into account the effect of possible temperature and precipitation trends on recharge rates. Following a previous experience with model conceptualization and long-term simulation of groundwater flow, an integrated three-dimensional groundwater model has been developed for the Monte Coscerno aquifer. In a previous paper (Preziosi et al 2014) the spatial distribution of recharge to this aquifer was estimated through the Thornthwaite Mather model at a daily time step using as inputs past precipitation and temperature values (1951-2013) as well as soil and landscape properties. In this paper the numerical model development is described. On the basis of well logs from private consulting companies and literature cross sections the

  13. Response to Comment on "Dilution limits dissolved organic carbon utilization in the deep ocean"

    KAUST Repository

    Arrieta, Jesus

    2015-12-18

    Our recent finding that dilution limits dissolved organic carbon (DOC) utilization in the deep ocean has been criticized based on the common misconception that lability equates to rapid and complete utilization. Even when considering the redefinition of recalcitrant DOC recently proposed by Jiao et al., the dilution hypothesis best explains our experimental observations.

  14. Increasing carbon availability stimulates growth and secondary metabolites via modulation of phytohormones in winter wheat

    Science.gov (United States)

    Reichelt, Michael; Chowdhury, Somak; Hammerbacher, Almuth; Hartmann, Henrik

    2017-01-01

    Abstract Phytohormones play important roles in plant acclimation to changes in environmental conditions. However, their role in whole-plant regulation of growth and secondary metabolite production under increasing atmospheric CO2 concentrations ([CO2]) is uncertain but crucially important for understanding plant responses to abiotic stresses. We grew winter wheat (Triticum aestivum) under three [CO2] (170, 390, and 680 ppm) over 10 weeks, and measured gas exchange, relative growth rate (RGR), soluble sugars, secondary metabolites, and phytohormones including abscisic acid (ABA), auxin (IAA), jasmonic acid (JA), and salicylic acid (SA) at the whole-plant level. Our results show that, at the whole-plant level, RGR positively correlated with IAA but not ABA, and secondary metabolites positively correlated with JA and JA-Ile but not SA. Moreover, soluble sugars positively correlated with IAA and JA but not ABA and SA. We conclude that increasing carbon availability stimulates growth and production of secondary metabolites via up-regulation of auxin and jasmonate levels, probably in response to sugar-mediated signalling. Future low [CO2] studies should address the role of reactive oxygen species (ROS) in leaf ABA and SA biosynthesis, and at the transcriptional level should focus on biosynthetic and, in particular, on responsive genes involved in [CO2]-induced hormonal signalling pathways. PMID:28159987

  15. Trade-offs for food production, nature conservation and climate limit the terrestrial carbon dioxide removal potential.

    Science.gov (United States)

    Boysen, Lena R; Lucht, Wolfgang; Gerten, Dieter

    2017-10-01

    Large-scale biomass plantations (BPs) are a common factor in climate mitigation scenarios as they promise double benefits: extracting carbon from the atmosphere and providing a renewable energy source. However, their terrestrial carbon dioxide removal (tCDR) potentials depend on important factors such as land availability, efficiency of capturing biomass-derived carbon and the timing of operation. Land availability is restricted by the demands of future food production depending on yield increases and population growth, by requirements for nature conservation and, with respect to climate mitigation, avoiding unfavourable albedo changes. We integrate these factors in one spatially explicit biogeochemical simulation framework to explore the tCDR opportunity space on land available after these constraints are taken into account, starting either in 2020 or 2050, and lasting until 2100. We find that assumed future needs for nature protection and food production strongly limit tCDR potentials. BPs on abandoned crop and pasture areas (~1,300 Mha in scenarios of either 8.0 billion people and yield gap reductions of 25% until 2020 or 9.5 billion people and yield gap reductions of 50% until 2050) could, theoretically, sequester ~100 GtC in land carbon stocks and biomass harvest by 2100. However, this potential would be ~80% lower if only cropland was available or ~50% lower if albedo decreases were considered as a factor restricting land availability. Converting instead natural forest, shrubland or grassland into BPs could result in much larger tCDR potentials ̶ but at high environmental costs (e.g. biodiversity loss). The most promising avenue for effective tCDR seems to be improvement of efficient carbon utilization pathways, changes in dietary trends or the restoration of marginal lands for the implementation of tCDR. © 2017 John Wiley & Sons Ltd.

  16. Decreased carbon limitation of litter respiration in a mortality-affected pinon-juniper woodland

    Science.gov (United States)

    Erin Berryman; John D. Marshall; Thom Rahn; Marcie Litvak; John Butnor

    2013-01-01

    Microbial respiration depends on microclimatic variables and carbon (C) substrate availability, all of which are altered when ecosystems experience major disturbance. Widespread tree mortality, currently affecting pinon-juniper ecosystems in southwestern North America, may affect C substrate availability in several ways, for example, via litterfall pulses and loss of...

  17. SAGES: a suite of freely-available software tools for electronic disease surveillance in resource-limited settings.

    Directory of Open Access Journals (Sweden)

    Sheri L Lewis

    Full Text Available Public health surveillance is undergoing a revolution driven by advances in the field of information technology. Many countries have experienced vast improvements in the collection, ingestion, analysis, visualization, and dissemination of public health data. Resource-limited countries have lagged behind due to challenges in information technology infrastructure, public health resources, and the costs of proprietary software. The Suite for Automated Global Electronic bioSurveillance (SAGES is a collection of modular, flexible, freely-available software tools for electronic disease surveillance in resource-limited settings. One or more SAGES tools may be used in concert with existing surveillance applications or the SAGES tools may be used en masse for an end-to-end biosurveillance capability. This flexibility allows for the development of an inexpensive, customized, and sustainable disease surveillance system. The ability to rapidly assess anomalous disease activity may lead to more efficient use of limited resources and better compliance with World Health Organization International Health Regulations.

  18. The effect of limited availability of N or water on C allocation to fine roots and annual fine root turnover in Alnus incana and Salix viminalis.

    Science.gov (United States)

    Rytter, Rose-Marie

    2013-09-01

    The effect of limited nitrogen (N) or water availability on fine root growth and turnover was examined in two deciduous species, Alnus incana L. and Salix viminalis L., grown under three different regimes: (i) supply of N and water in amounts which would not hamper growth, (ii) limited N supply and (iii) limited water supply. Plants were grown outdoors during three seasons in covered and buried lysimeters placed in a stand structure and filled with quartz sand. Computer-controlled irrigation and fertilization were supplied through drip tubes. Production and turnover of fine roots were estimated by combining minirhizotron observations and core sampling, or by sequential core sampling. Annual turnover rates of fine roots water availability. Fine root production (treatments in Salix; i.e., absolute length and biomass production increased in the order: water limited treatment effects were detected for fine roots 1-2 mm. Proportionally more C was allocated to fine roots (≤2 mm) in N or water-limited Salix; 2.7 and 2.3 times the allocation to fine roots in the unlimited regime, respectively. Estimated input to soil organic carbon increased by ca. 20% at N limitation in Salix. However, future studies on fine root decomposition under various environmental conditions are required. Fine root growth responses to N or water limitation were less pronounced in Alnus, thus indicating species differences caused by N-fixing capacity and slower initial growth in Alnus, or higher fine root plasticity in Salix. A similar seasonal growth pattern across species and treatments suggested the influence of outer stimuli, such as temperature and light.

  19. Analysis of erosion and transport of carbon impurity in the TFTR inner bumper limiter region

    International Nuclear Information System (INIS)

    Hua, T.Q.; Brooks, J.N.

    1992-01-01

    Carbon sputtering and transport on the TFTR inner graphite bumper limiter is investigated with the impurity transport code REDEP. Analysis is carried out for a series of ohmic discharges in TFTR. Predictions for Z eff in the core plasma agree well with in-situ experimental measurements. Run-away self-sputtering of carbon is predicted at low densities and high edge plasma temperatures when the limiter surface was purged of deuterium. Surface erosion and deposition is analyzed. In general, redeposition reduces the peak erosion by about a factor of five. Analysis is also carried out for a typical neutral beam heated discharge with a noncircular plasma. Spatial surface erosion and deposition profiles are compared qualitatively with beta backscattering measurements of metal deposition found on the limiter

  20. Carbon capture in vehicles : a review of general support, available mechanisms, and consumer-acceptance issues.

    Science.gov (United States)

    2012-05-01

    This survey of the feasibility of introducing carbon capture and storage (CCS) into light vehicles : started by reviewing the level of international support for CCS in general. While there have been : encouraging signs that CCS is gaining acceptance ...

  1. Control of Seed Germination and Plant Development by Carbon and Nitrogen Availability

    Directory of Open Access Journals (Sweden)

    Daniel eOsuna

    2015-11-01

    Full Text Available Little is known about the molecular basis of the influence of external carbon/nitrogen (C/N ratio and other abiotic factors on phytohormones regulation during seed germination and plant developmental processes, and the identification of elements that participate in this response is essential to understand plant nutrient perception and signaling. Sugars (sucrose, glucose and nitrate not only act as nutrients but also as signaling molecules in plant development. A connection between changes in auxin transport and nitrate signal transduction has been reported in Arabidopsis thaliana through the NRT1.1, a nitrate sensor and transporter that also functions as a repressor of lateral root growth under low concentrations of nitrate by promoting auxin transport. Nitrate inhibits the elongation of lateral roots, but this effect is significantly reduced in abscisic acid (ABA-insensitive mutants, what suggests that ABA might mediate the inhibition of lateral root elongation by nitrate. Gibberellin (GA biosynthesis has been also related to nitrate level in seed germination and its requirement is determined by embryonic ABA. These mechanisms connect nutrients and hormones signaling during seed germination and plant development. Thus, the genetic identification of the molecular components involved in nutrients-dependent pathways would help to elucidate the potential crosstalk between nutrients, nitric oxide (NO and phytohormones (ABA, auxins and GAs in seed germination and plant development. In this review we focus on changes in C and N levels and how they control seed germination and plant developmental processes through the interaction with other plant growth regulators, such as phytohormones.

  2. Independence of nutrient limitation and carbon dioxide impacts on the Southern Ocean coccolithophore Emiliania huxleyi.

    Science.gov (United States)

    Müller, Marius N; Trull, Thomas W; Hallegraeff, Gustaaf M

    2017-08-01

    Future oceanic conditions induced by anthropogenic greenhouse gas emissions include warming, acidification and reduced nutrient supply due to increased stratification. Some parts of the Southern Ocean are expected to show rapid changes, especially for carbonate mineral saturation. Here we compare the physiological response of the model coccolithophore Emiliania huxleyi (strain EHSO 5.14, originating from 50 o S, 149 o E) with pH/CO 2 gradients (mimicking ocean acidification ranging from 1 to 4 × current pCO 2 levels) under nutrient-limited (nitrogen and phosphorus) and -replete conditions. Both nutrient limitations decreased per cell photosynthesis (particulate organic carbon (POC) production) and calcification (particulate inorganic carbon (PIC) production) rates for all pCO 2 levels, with more than 50% reductions under nitrogen limitation. These impacts, however, became indistinguishable from nutrient-replete conditions when normalized to cell volume. Calcification decreased three-fold and linearly with increasing pCO 2 under all nutrient conditions, and was accompanied by a smaller ~30% nonlinear reduction in POC production, manifested mainly above 3 × current pCO 2 . Our results suggest that normalization to cell volume allows the major impacts of nutrient limitation (changed cell sizes and reduced PIC and POC production rates) to be treated independently of the major impacts of increasing pCO 2 and, additionally, stresses the importance of including cell volume measurements to the toolbox of standard physiological analysis of coccolithophores in field and laboratory studies.

  3. Does carbon availability control temporal dynamics of radial growth in Norway spruce (Picea abies)?

    Science.gov (United States)

    Oberhuber, Walter; Gruber, Andreas; Swidrak, Irene

    2015-04-01

    Intra-annual dynamics of cambial activity and wood formation of coniferous species exposed to soil dryness revealed early culmination of maximum growth in late spring prior to occurrence of more favourable environmental conditions, i.e., repeated high rainfall events during summer (Oberhuber et al. 2014). Because it is well known that plants can adjust carbon allocation patterns to optimize resource uptake under prevailing environmental constraints, we hypothesize that early decrease in radial stem growth is an adaptation to cope with drought stress, which might require an early switch of carbon allocation to belowground organs. Physical blockage of carbon transport in the phloem through girdling causes accumulation and depletion of carbohydrates above and below the girdle, respectively, making this method quite appropriate to investigate carbon relationships in trees. Hence, in a common garden experiment we will manipulate the carbon status of Norway spruce (Picea abies) saplings by phloem blockage at different phenological stages during the growing season. We will present the methodological approach and first results of the study aiming to test the hypothesis that carbon status of the tree affects temporal dynamics of cambial activity and wood formation in conifers under drought. Acknowledgment The research is funded by the Austrian Science Fund (FWF): P25643-B16 "Carbon allocation and growth of Scots pine". Reference Oberhuber W, A Gruber, W Kofler, I Swidrak (2014) Radial stem growth in response to microclimate and soil moisture in a drought-prone mixed coniferous forest at an inner Alpine site. Eur J For Res 133:467-479.

  4. Linking carbon and water limitations to drought-induced mortality of Pinus flexilis seedlings

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J.; Kueppers, Lara M.; Domec, Jean-Christophe; Mitton, Jeffry

    2015-01-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below −5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations.

  5. Transportation Energy Futures Series: Alternative Fuel Infrastructure Expansion: Costs, Resources, Production Capacity, and Retail Availability for Low-Carbon Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heath, Garvin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sandor, Debra [National Renewable Energy Lab. (NREL), Golden, CO (United States); Steward, Darlene [National Renewable Energy Lab. (NREL), Golden, CO (United States); Vimmerstedt, Laura [National Renewable Energy Lab. (NREL), Golden, CO (United States); Warner, Ethan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Webster, Karen W. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-04-01

    The petroleum-based transportation fuel system is complex and highly developed, in contrast to the nascent low-petroleum, low-carbon alternative fuel system. This report examines how expansion of the low-carbon transportation fuel infrastructure could contribute to deep reductions in petroleum use and greenhouse gas (GHG) emissions across the U.S. transportation sector. Three low-carbon scenarios, each using a different combination of low-carbon fuels, were developed to explore infrastructure expansion trends consistent with a study goal of reducing transportation sector GHG emissions to 80% less than 2005 levels by 2050.These scenarios were compared to a business-as-usual (BAU) scenario and were evaluated with respect to four criteria: fuel cost estimates, resource availability, fuel production capacity expansion, and retail infrastructure expansion.

  6. Corrosion of bare carbon steel as a passive sensor to assess moisture availability for biological activity in Atacama Desert soils.

    Science.gov (United States)

    Cáceres, Luis; Davila, Alfonso F; Soliz, Alvaro; Saldivia, Jessica

    2018-02-28

    Here we consider that the corrosion of polished bared metal coupons can be used as a passive sensor to detect or identify the lower limit of water availability suitable for biological activity in Atacama Desert soils or solid substrates. For this purpose, carbon steel coupons were deposited at selected sites along a west-east transect and removed at predetermined times for morphological inspection. The advantage of this procedure is that the attributes of the oxide layer (corrosion extent, morphology and oxide phases) can be considered as a fingerprint of the atmospheric moisture history at a given time interval. Two types of coupons were used, long rectangular shaped ones that were half-buried in a vertical position, and square shaped ones that were deposited on the soil surface. The morphological attributes observed by SEM inspection were found to correlate to the so-called humectation time which is determined from local meteorological parameters. The main finding was that the decreasing trend of atmospheric moisture along the transect was closely related to corrosion behaviour and water soil penetration. For instance, at the coastal site oxide phases formed on the coupon surface rapidly evolve into well-crystallized species, while at the driest inland site Lomas Bayas only amorphous oxide was observed on the coupons.

  7. Corrosion of Bare Carbon Steel as a Passive Sensor to Assess Moisture Availability for Biological Activity in Atacama Desert Soils

    Science.gov (United States)

    Caceres, Luis; Davila, Alfonso F.; Soliz, Alvaro; Saldivia, Jessica

    2018-01-01

    In this work we suggest the corrosion of polished bared metal coupons as a passive sensor to detect or identify the lower limit of water availability that could be suitable for biological activity in the Atacama Desert on soil or solid substrates. For this purpose, carbon steel coupons were deposited in selected sites along a west-east transect and removed at predetermined times for morphological inspection. The advantage of this procedure is that the attributes of the oxide layer (corrosion extent, morphology and oxide phases) can be considered as a fingerprint of the atmospheric moisture history at a given time interval. Two types of coupons were used, a long rectangular shape that are half-buried in a vertical position, and square shape that are deposited on the soil surface. The morphological attributes observed by SEM inspection is correlated to the so-called humectation time which is determined from local meteorological parameters. The main result is that the decreasing trend of atmospheric moisture along the transect is closely related to corrosion behavior and water soil penetration. For instance, while in the coastal site oxide phases formed on the coupon surface rapidly evolve to well- crystallized species, in the driest inland site Lomas Bayas only amorphous oxide is observed.

  8. Influence of initial heterogeneities and recharge limitations on the evolution of aperture distributions in carbonate aquifers

    Directory of Open Access Journals (Sweden)

    B. Hubinger

    2011-12-01

    Full Text Available Karst aquifers evolve where the dissolution of soluble rocks causes the enlargement of discrete pathways along fractures or bedding planes, thus creating highly conductive solution conduits. To identify general interrelations between hydrogeological conditions and the properties of the evolving conduit systems the aperture-size frequency distributions resulting from generic models of conduit evolution are analysed. For this purpose, a process-based numerical model coupling flow and rock dissolution is employed. Initial protoconduits are represented by tubes with log-normally distributed aperture sizes with a mean μ0 = 0.5 mm for the logarithm of the diameters. Apertures are spatially uncorrelated and widen up to the metre range due to dissolution by chemically aggressive waters. Several examples of conduit development are examined focussing on influences of the initial heterogeneity and the available amount of recharge. If the available recharge is sufficiently high the evolving conduits compete for flow and those with large apertures and high hydraulic gradients attract more and more water. As a consequence, the positive feedback between increasing flow and dissolution causes the breakthrough of a conduit pathway connecting the recharge and discharge sides of the modelling domain. Under these competitive flow conditions dynamically stable bimodal aperture distributions are found to evolve, i.e. a certain percentage of tubes continues to be enlarged while the remaining tubes stay small-sized. The percentage of strongly widened tubes is found to be independent of the breakthrough time and decreases with increasing heterogeneity of the initial apertures and decreasing amount of available water. If the competition for flow is suppressed because the availability of water is strongly limited breakthrough of a conduit pathway is inhibited and the conduit pathways widen very slowly. The resulting aperture distributions are found to be

  9. 40 CFR Table 5 to Subpart Jjj of... - Carbon Monoxide Emission Limits for Existing Small Municipal Waste Combustion Units

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Carbon Monoxide Emission Limits for Existing Small Municipal Waste Combustion Units 5 Table 5 to Subpart JJJ of Part 62 Protection of... of Part 62—Carbon Monoxide Emission Limits for Existing Small Municipal Waste Combustion Units...

  10. 40 CFR Table 2 to Subpart Aaaa of... - Carbon Monoxide Emission Limits for New Small Municipal Waste Combustion Units

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Carbon Monoxide Emission Limits for New... Pt. 60, Subpt. AAAA, Table 2 Table 2 to Subpart AAAA of Part 60—Carbon Monoxide Emission Limits for.... Compliance is determined by continuous emission monitoring systems. b Block averages, arithmetic mean. See...

  11. Extended Le Chatelier's formula for carbon dioxide dilution effect on flammability limits.

    Science.gov (United States)

    Kondo, Shigeo; Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki

    2006-11-02

    Carbon dioxide dilution effect on the flammability limits was measured for various flammable gases. The obtained values were analyzed using the extended Le Chatelier's formula developed in a previous study. As a result, it has been found that the flammability limits of methane, propane, propylene, methyl formate, and 1,1-difluoroethane are adequately explained by the extended Le Chatelier's formula using a common set of parameter values. Ethylene, dimethyl ether, and ammonia behave differently from these compounds. The present result is very consistent with what was obtained in the case of nitrogen dilution.

  12. Flaking of co-deposited hydrogenated carbon layers on the TFTR limiter

    International Nuclear Information System (INIS)

    Skinner, C.H.; Gentile, C.A.; Menon, M.M.; Barry, R.E.

    1999-01-01

    Flaking of co-deposited layers on the inner limiter tiles was recently observed in TFTR. This phenomenon was unexpected and has occurred since the termination of plasma operations on 4 April 1997. Flaking affects approximately 15% of the observable tiles and appears on isotropic graphite but not on carbon fibre composite tiles. Photographic images of the flakes and precise measurements of the limiter geometry are reported. The mobilizability of tritium retained in co-deposited layers is an important factor in safety analyses of future DT reactors. A programme to analyse the flakes and tiles is underway. (author). Letter-to-the-editor

  13. Polyol synthesis in Aspergillus niger : influence of oxygen availability, carbon and nitrogen sources on the metabolism

    DEFF Research Database (Denmark)

    Diano, Audrey; Bekker-Jensen, S; Dynesen, Jens Østergaard

    2006-01-01

    Polyol production has been studied in Aspergillus niger under different conditions. Fermentations have been run using high concentration of glucose or xylose as carbon source and ammonium or nitrate as nitrogen source. The growth of biomass, as freely dispersed hyphae, led to an increase of medium...

  14. Carbon availability triggers fungal nitrogen uptake and transport in arbuscular mycorrhizal symbiosis.

    NARCIS (Netherlands)

    Fellbaum, C.R.; Gachomo, E.W.; Beesetty, Y.; Choudhari, S.; Strahan, G.D.; Pfeffer, P.E.; Kiers, E.T.; Bücking, H.

    2012-01-01

    The arbuscular mycorrhizal (AM) symbiosis, formed between the majority of land plants and ubiquitous soil fungi of the phylum Glomeromycota, is responsible for massive nutrient transfer and global carbon sequestration. AM fungi take up nutrients from the soil and exchange them against

  15. Physiology of Aspergillus niger in Oxygen-Limited Continuous Cultures: Influence of Aeration, Carbon Source Concentration and Dilution Rate

    DEFF Research Database (Denmark)

    Diano, Audrey; Peeters, J.; Dynesen, Jens Østergaard

    2009-01-01

    In industrial production of enzymes using the filamentous fungus Aspergilhis niger supply of sufficient oxygen is often a limitation, resulting in the formation of by-products such as polyols. In order to identify the mechanisms behind formation of the different by-products we studied the effect...... of low oxygen availability, at different carbon source concentrations and at different specific growth rates, on the metabolism of A. niger, using continuous cultures. The results show that there is an increase in the production of tricarboxylic acid (TCA) cycle intermediates at low oxygen concentrations...

  16. How low can you go? Assessing minimum concentrations of NSC in carbon limited tree saplings

    Science.gov (United States)

    Hoch, Guenter; Hartmann, Henrik; Schwendener, Andrea

    2016-04-01

    Tissue concentrations of non-structural carbohydrates (NSC) are frequently used to determine the carbon balance of plants. Over the last years, an increasing number of studies have inferred carbon starvation in trees under environmental stress like drought from low tissue NSC concentrations. However, such inferences are limited by the fact that minimum concentrations of NSC required for survival are not known. So far, it was hypothesized that even under lethal carbon starvation, starch and low molecular sugar concentrations cannot be completely depleted and that minimum NSC concentrations at death vary across tissues and species. Here we present results of an experiment that aimed to determine minimum NSC concentrations in different tissues of saplings of two broad-leaved tree species (Acer pseudoplatanus and Quercus petratea) exposed to lethal carbon starvation via continuous darkening. In addition, we investigated recovery rates of NSC concentrations in saplings that had been darkened for different periods of time and were then re-exposed to light. Both species survived continuous darkening for about 12 weeks (confirmed by testing the ability to re-sprout after darkness). In all investigated tissues, starch concentrations declined close to zero within three to six weeks of darkness. Low molecular sugars also decreased strongly within the first weeks of darkness, but seemed to stabilize at low concentrations of 0.5 to 2 % dry matter (depending on tissue and species) almost until death. NSC concentrations recovered surprisingly fast in saplings that were re-exposed to light. After 3 weeks of continuous darkness, tissue NSC concentrations recovered within 6 weeks to levels of unshaded control saplings in all tissues and in both species. To our knowledge, this study represents the first experimental attempt to quantify minimum tissue NSC concentrations at lethal carbon starvation. Most importantly, our results suggest that carbon-starved tree saplings are able to

  17. Water table and species identity outweigh carbon and nitrogen availability in a softwater plant community

    Science.gov (United States)

    Vanderhaeghe, Floris; Smolders, Alfons J. P.; Roelofs, Jan G. M.; Hoffmann, Maurice

    2013-02-01

    Performance of aquatic macrophytes is driven by many environmental factors, and a major challenge is to understand how aquatic macrophyte communities are structured in various environments. In softwater lakes in Western Europe, hydrological state (submersed/emersed), carbon dioxide and ammonium levels and species interactions are considered as driving forces in structuring amphibious plant communities. In this study we aimed at evaluating the relative importance of these factors for four species in a competitive neighbourhood. Softwater lake habitat was simulated during one growing season in laboratory conditions, mimicking water level fluctuation, photoperiod and temperature. Artificial communities consisted of small populations of four softwater macrophyte species: Luronium natans, Baldellia ranunculoides ssp. repens, Eleocharis multicaulis and Hydrocotyle vulgaris. These communities were subjected to two levels of carbon dioxide and ammonium. Additionally, monocultures of Baldellia and Eleocharis were grown at a higher nutrient level combination in order to measure their competitive response in a community. Time (hydrological state) and species identity turned out to be the only consistently significant factors determining community composition. Plant performance was clearly species-dependent, while carbon dioxide and ammonium did not have major effects. The competitive response was significant in both Eleocharis and Baldellia. Competition intensity was highest in the emersed state. Carbon dioxide had a supplementary effect on the within-species performance in Luronium, Baldellia and Eleocharis, with high carbon dioxide level mainly resulting in more flowers and more stolons. Community outcomes and competitive responses in aquatic macrophytes appear difficult to predict, because of mixed life strategies and morphological and functional plasticity. We conclude that hydrological state was the only important environmental factor. The identity of the species that

  18. Effect of ICRH on the JET edge plasma with carbon and beryllium coated limiters

    International Nuclear Information System (INIS)

    Clement, S.; Erents, S.K.; Tagle, J.A.; Brinkschulte, H.; Bures, M.; De Kock, L.

    1990-01-01

    Investigation of the scrape-off Layer (SOL) at different poloidal positions has been carried out with Langmuir probes for limiter discharges with ion cyclotron resonance heating (ICRH) at JET. A comparison of the effects of ICRH on the edge is presented for operation with all carbon limiters, and for operation with a beryllium layer evaporated on the walls and limiters of JET. The behaviour of the SOL parameters is similar for both cases, although edge temperatures tend to be lower in the Be case. Measurements with probes between the belt limiters and close to the ICRH antennas show that the edge parameters in this region are strongly influenced by the vicinity of an active antenna. (orig.)

  19. Expanding dryland ecosystem flux datasets enable novel quantification of water availability and carbon exchange in Southwestern North America

    Science.gov (United States)

    Biederman, J. A.; Scott, R. L.; Smith, W. K.; Litvak, M. E.; MacBean, N.

    2017-12-01

    Global-scale studies suggest that water-limited dryland ecosystems dominate the increasing trend in magnitude and interannual variability of the land CO2 sink. However, the terrestrial biosphere models and remote sensing models used in large-scale analyses are poorly constrained by flux measurements in drylands, which are under-represented in global datasets. In this talk, I will address this gap with eddy covariance data from 30 ecosystems across the Southwest of North America with observed ranges in annual precipitation of 100 - 1000 mm, annual temperatures of 2 - 25 °C, and records of 3 - 10 years each (160 site-years). This extensive dryland dataset enables new approaches including 1) separation of temporal and spatial patterns to infer fast and slow ecosystem responses to change, and 2) partitioning of precipitation into hydrologic losses, evaporation, and ecosystem-available water. I will then compare direct flux measurements with models and remote sensing used to scale fluxes regionally. Combining eddy covariance and streamflow measurements, I will show how evapotranspiration (ET), which is the efflux of soil moisture remaining after hydrologic losses, is a better metric than precipitation of water available to drive ecosystem CO2 exchange. Furthermore, I will present a novel method to partition ET into evaporation and transpiration using the tight coupling of transpiration and photosynthesis. In contrast with typical carbon sink function in wetter, more-studied regions, dryland sites express an annual net carbon uptake varying from -350 to +330 gC m-2. Due to less respiration losses relative to photosynthesis gains during winter, declines in winter precipitation across the Southwest since 1999 are reducing annual net CO2 uptake. Interannual variability of net uptake is larger than for wetter regions, and half the sites pivot between sinks in wet years to sources in dry years. Biospheric and remote sensing models capture only 20-30 % of interannual

  20. Decreased carbon limitation of litter respiration in a mortality-affected piñon–juniper woodland

    Directory of Open Access Journals (Sweden)

    E. Berryman

    2013-03-01

    Full Text Available Microbial respiration depends on microclimatic variables and carbon (C substrate availability, all of which are altered when ecosystems experience major disturbance. Widespread tree mortality, currently affecting piñon–juniper ecosystems in southwestern North America, may affect C substrate availability in several ways, for example, via litterfall pulses and loss of root exudation. To determine piñon mortality effects on C and water limitation of microbial respiration, we applied field amendments (sucrose and water to two piñon–juniper sites in central New Mexico, USA: one with a recent (2 flux on the girdled site and a non-significant increase on the control. We speculate that the reduction may have been driven by water-induced carbonate dissolution, which serves as a sink for CO2 and would reduce the net flux. Widespread piñon mortality may decrease labile C limitation of litter respiration, at least during the first growing season following mortality.

  1. Statistical analysis of the limitation of half integer resonances on the available momentum acceptance of the High Energy Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Yi, E-mail: jiaoyi@ihep.ac.cn; Duan, Zhe

    2017-01-01

    In a diffraction-limited storage ring, half integer resonances can have strong effects on the beam dynamics, associated with the large detuning terms from the strong focusing and strong sextupoles as required for an ultralow emittance. In this study, the limitation of half integer resonances on the available momentum acceptance (MA) was statistically analyzed based on one design of the High Energy Photon Source (HEPS). It was found that the probability of MA reduction due to crossing of half integer resonances is closely correlated with the level of beta beats at the nominal tunes, but independent of the error sources. The analysis indicated that for the presented HEPS lattice design, the rms amplitude of beta beats should be kept below 1.5% horizontally and 2.5% vertically to reach a small MA reduction probability of about 1%.

  2. Is the development of falciparum malaria in the human host limited by the availability of uninfected erythrocytes?

    Directory of Open Access Journals (Sweden)

    Hoshen M B

    2002-12-01

    Full Text Available Abstract Background The development and propagation of malaria parasites in their vertebrate host is a complex process in which various host and parasite factors are involved. Sometimes the evolution of parasitaemia seems to be quelled by parasite load. In order to understand the typical dynamics of evolution of parasitaemia, various mathematical models have been developed. The basic premise ingrained in most models is that the availability of uninfected red blood cells (RBC in which the parasite develops is a limiting factor in the propagation of the parasite population. Presentation of the hypothesis We would like to propose that except in extreme cases of severe malaria, there is no limitation in the supply of uninfected RBC for the increase of parasite population. Testing the hypothesis In this analysis we examine the biological attributes of the parasite-infected RBC such as cytoadherence and rosette formation, and the rheological properties of infected RBC, and evaluate their effects on blood flow and clogging of capillaries. We argue that there should be no restriction in the availability of uninfected RBC in patients. Implication of the hypothesis There is no justification for the insertion of RBC supply as a factor in mathematical models that describe the evolution of parasitaemia in the infected host. Indeed, more recent models, that have not inserted this factor, successfully describe the evolution of parasitaemia in the infected host.

  3. Best Available Technique (BAT) as an Instrument for the Limitation of Radioactive Substances from Nuclear Power Reactors in Sweden

    International Nuclear Information System (INIS)

    Moberg, L.; Sundell-Bergman, S.; Sandwall, J.

    2004-01-01

    Traditionally, the concept of ALARA has been the basis for limitation and optimisation of releases of radioactive substances from nuclear power reactors in order to protect human health. In recent years, it has been discussed whether the ALARA principle can be applied also to protect the environment. For the protection of the environment, in particular for non-nuclear pollutants, the precautionary principle and the concept of Best Available Technique (BAT) have been applied. New Swedish regulations concerning the protection of human health and the environment from radioactive discharges from certain nuclear installations entered into force January 1st, 2002. The prime purpose of the regulations is to limit the radioactive releases. This limitation shall be based on the optimisation of radiation protection and shall be achieved by using BAT. In order to show compliance with the regulation and BAT, the concepts of reference values and target values have been introduced for nuclear power reactors. The reference value should be the release that is representative for optimum use and full functioning of systems of importance to the occurrence and limitation of radioactive releases from nuclear power reactors. The target value should show the level to which radioactive releases from nuclear power reactors can be reduced during a certain given period of time. Reference and target values have been determined for each nuclear power reactor in Sweden. Each year, the reactor licensees shall report to the Swedish Radiation Protection Authority (SSI) the measures that have been adopted or that are planned to be adopted to limit radioactive releases with the aim of achieving the target values. The first report has been submitted to the SSI in 2003. (Author) 8 refs

  4. Job Accommodations Availability and Utilization Among People With Lupus: An Examination of Workplace Activity Limitations and Work Context Factors.

    Science.gov (United States)

    Al Dhanhani, Ali M; Gignac, Monique A M; Beaton, Dorcas E; Su, Jiandong; Fortin, Paul R

    2015-11-01

    The aim of this study was to examine the availability of diverse job accommodations (or flexible working arrangements) and to describe their use among people with systemic lupus erythematosus (lupus), as well as to examine factors associated with the use of job accommodations. A mail survey was sent to adult lupus patients receiving care from a lupus clinic based in Toronto, Canada. The survey assessed demographic information, self-reported disease activity, work history, workplace activity limitations, job strain, and the availability and use of job accommodations. Standard multivariable linear regression analysis was used to examine factors associated with the use of job accommodations. We received 362 responses of 604 mailed surveys (60% response rate). Participants who were employed within the last 5 years, but who were not currently working, were less likely than currently employed participants to report having had job accommodations available to them at their last place of employment. The use of job accommodations was reported by 70% of currently employed respondents and by 72% of those not currently employed. The most common job accommodation used was sick leave days. Factors positively associated with the use of job accommodations among those who were employed included higher levels of education, being diagnosed with fibromyalgia, at least 1 episode of short-term work disability, not belonging to a union, greater workplace activity limitations, and greater job strain. The use of job accommodations among people with lupus is common. Work context factors, such as workplace activity limitations and job strain, are the main factors associated with the use of job accommodations. © 2015, American College of Rheumatology.

  5. Testing the limits in a greenhouse ocean: Did low nitrogen availability limit marine productivity during the end-Triassic mass extinction?

    Science.gov (United States)

    Schoepfer, Shane D.; Algeo, Thomas J.; Ward, Peter D.; Williford, Kenneth H.; Haggart, James W.

    2016-10-01

    The end-Triassic mass extinction has been characterized as a 'greenhouse extinction', related to rapid atmospheric warming and associated changes in ocean circulation and oxygenation. The response of the marine nitrogen cycle to these oceanographic changes, and the extent to which mass extinction intervals represent a deviation in nitrogen cycling from other ice-free 'greenhouse' periods of Earth history, remain poorly understood. The well-studied Kennecott Point section in Haida Gwaii, British Columbia, Canada, was deposited in the open Panthalassic Ocean, and is used here as a test case to better understand changes in the nitrogen cycle and marine productivity from the pre-crisis greenhouse of the Rhaetian to the latest-Rhaetian crisis interval. We estimated marine productivity from the late Norian to the early Hettangian using TOC- and P-based paleoproductivity transform equations, and then compared these estimates to records of sedimentary nitrogen isotopes, redox-sensitive trace elements, and biomarker data. Major negative excursions in δ15N (to ≤ 0 ‰) correspond to periods of depressed marine productivity. During these episodes, the development of a stable pycnocline below the base of the photic zone suppressed vertical mixing and limited N availability in surface waters, leading to low productivity and increased nitrogen fixation, as well as ecological stresses in the photic zone. The subsequent shoaling of euxinic waters into the ocean surface layer was fatal for most Triassic marine fauna, although the introduction of regenerated NH4+ into the photic zone may have allowed phytoplankton productivity to recover. These results indicate that the open-ocean nitrogen cycle was influenced by climatic changes during the latest Triassic, despite having existed in a greenhouse state for over 50 million years previously, and that low N availability limited marine productivity for hundreds of thousands of years during the end-Triassic crisis.

  6. Evidence of hot spot formation on carbon limiters due to thermal electron emission

    International Nuclear Information System (INIS)

    Philipps, V.; Samm, U.; Tokar, M.Z.; Unterberg, B.; Pospieszczyk, A.; Schweer, B.

    1993-01-01

    Carbon test limiters have been exposed in TEXTOR to high heat loads up to about 30 MW/m 2 . The evolutions of the surface temperature distribution and of the carbon release have been observed by means of local diagnostics. A sudden acceleration of the rise of the surface temperature has been found at a critical temperature of approx. 2400 deg. C. The increase of the rate of the temperature rise is consistent with an enhancement of the power loading by a factor of 2.5-3. Following the temperature jump (hot spot), a quasi-equilibrium temperature establishes at approx. 2700 deg. C. The development of the hot spot is explained by an increase of the local power loading to the breakdown of the sheath potential by thermal emission of electrons from the carbon surface. Simultaneously with the appearance of the hot spot, the carbon release from the surface increases sharply. This increase can be explained by normal thermal sublimation. Sublimation cooling contributes to the establishment of the quasi-equilibrium temperature at about 2700 deg. C. (author). 16 refs, 10 figs

  7. Reversible thermal fusing model of carbon black current-limiting thermistors

    International Nuclear Information System (INIS)

    Martin, James E.; Heaney, Michael B.

    2000-01-01

    Composites of carbon black particles in polyethylene exhibit an unusually rapid increase in resistivity as the applied electric field is increased, making this material commercially useful as current-limiting thermistors, also known as automatically resettable fuses. In this application the composite is in series with the circuit it is protecting: at low applied voltages the circuit is the load, but at high applied voltages the composite becomes the load, limiting the current to the circuit. We present a simple model of this behavior in terms of a network of nonlinear resistors. Each resistor has a resistance that depends explicitly and reversibly on its instantaneous power dissipation. This model predicts that in the soft fusing, or current-limiting, regime, where the current through the composite decreases with increasing voltage, a platelike dissipation instability develops normal to the applied field, in agreement with experimental observations, which is solely due to fluctuations in the microstructure

  8. Assessment of the SWAT model to simulate a watershed with limited available data in the Pampas region, Argentina.

    Science.gov (United States)

    Romagnoli, Martín; Portapila, Margarita; Rigalli, Alfredo; Maydana, Gisela; Burgués, Martín; García, Carlos M

    2017-10-15

    Argentina has been among the world leaders in the production and export of agricultural products since the 1990s. The Carcarañá River Lower Basin (CRLB), a cropland of the Pampas region supplied by extensive rainfall, is located in an area with few streamgauging and other hydrologic/water-quality stations. Therefore, limited hydrologic data are available resulting in limited water-resources assessment. This work explores the application of Soil and Water Assessment Tool (SWAT) model to the CRLB in the Santa Fe province of the Pampas region. The analysis of field and remote-sensing data characterizing hydrology, water quality, soil types, land use/land cover, management practices, and crop yield, guarantee a comprehensive SWAT modeling approach. A combined manual and automated calibration and validation process incorporating sensitivity and uncertainty analysis is performed using information concerning interior watershed processes. Eleven N/P fertilizer rates are selected to simulate the impact of N fertilizer on crop yield, plant uptake, as well as runoff and leaching losses. Different indices (partial factor productivity, agronomic efficiency, apparent crop recovery efficiency of applied nutrient, internal utilization efficiency, and physiological efficiency) are considered to assess nitrogen-use efficiency. The overall quality of the fit is satisfactory considering the input data limitations. This work provides, for the first time in Argentina, a reliable tool to simulate yield response to soil quality and water availability capable to meet defined environmental targets to support decision making on planning public policies and private activities on the Pampas region. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Social incidence and economic costs of carbon limits; A computable general equilibrium analysis for Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Stephan, G.; Van Nieuwkoop, R.; Wiedmer, T. (Institute for Applied Microeconomics, Univ. of Bern (Switzerland))

    1992-01-01

    Both distributional and allocational effects of limiting carbon dioxide emissions in a small and open economy are discussed. It starts from the assumption that Switzerland attempts to stabilize its greenhouse gas emissions over the next 25 years, and evaluates costs and benefits of the respective reduction programme. From a methodological viewpoint, it is illustrated how a computable general equilibrium approach can be adopted for identifying economic effects of cutting greenhouse gas emissions on the national level. From a political economy point of view it considers the social incidence of a greenhouse policy. It shows in particular that public acceptance can be increased and economic costs of greenhouse policies can be reduced, if carbon taxes are accompanied by revenue redistribution. 8 tabs., 1 app., 17 refs.

  10. Mechanical coupling limits the density and quality of self-organized carbon nanotube growth

    Science.gov (United States)

    Bedewy, Mostafa; Hart, A. John

    2013-03-01

    Aligned carbon nanotube (CNT) structures are promising for many applications; however, as-grown CNT "forests" synthesized by chemical vapor deposition (CVD) are typically low-density and mostly comprise tortuous defective CNTs. Here, we present evidence that the density and alignment of self-organized CNT growth is limited by mechanical coupling among CNTs in contact, in combination with their diameter-dependent growth rates. This study is enabled by comprehensive X-ray characterization of the spatially and temporally-varying internal morphology of CNT forests. Based on this data, we model the time evolution and diameter-dependent scaling of the ensuing mechanical forces on catalyst nanoparticles during CNT growth, which arise from the mismatch between the collective lengthening rate of the forest and the diameter-dependent growth rates of individual CNTs. In addition to enabling self-organization of CNTs into forests, time-varying forces between CNTs in contact dictate the hierarchical tortuous morphology of CNT forests, and may be sufficient to influence the structural quality of CNTs. These forces reach a maximum that is coincident with the maximum density observed in our growth process, and are proportional to CNT diameter. Therefore, we propose that improved manufacturing strategies for self-organized CNTs should consider both chemical and mechanical effects. This may be especially necessary to achieve high density CNT forests with low defect density, such as for improved thermal interfaces and high-permeability membranes.Aligned carbon nanotube (CNT) structures are promising for many applications; however, as-grown CNT "forests" synthesized by chemical vapor deposition (CVD) are typically low-density and mostly comprise tortuous defective CNTs. Here, we present evidence that the density and alignment of self-organized CNT growth is limited by mechanical coupling among CNTs in contact, in combination with their diameter-dependent growth rates. This study is

  11. Light Intensity and Carbon Dioxide Availability Impact Antioxidant Activity in Green Onions (Allium fistulosumm L)

    Science.gov (United States)

    Levine, Lanfang; Bisbee, Patricia; Pare, Paul

    The prospect of long-duration manned space missions poses many challenges, including the development of a sustainable life support system and effective methods of space-radiation protection. To mitigate the risk of increased space-radiation, functional foods rich in antioxidant properties such as green onions are of particular interest. However it has yet to be established whether antioxidant properties can be preserved or enhanced in space environment where carbon dioxide, lighting intensity, gravity and pressure differ from which plants have acclimated to on earth. In this study, green onions (Allium fistulosumm L. cultivar Kinka) rich in antioxidant flavonoids are used as a model system to investigate variations in antioxidant capacity with plants grown under varying light intensities and CO2 concentrations. The antioxidant potential is determined using both radical cation scavenging and oxygen radical absorbance assays. For all light intensities assayed, antioxidant potential in water extract of green onions per gram biomass declined with CO2 increases up to 1200 ppm, and then leveled off with further CO2 increase to 4000 ppm. This inverse carbon dioxide versus antioxidant activity correlation suggests lower accumulation rates for water soluble antioxidant compounds compared to total biomass under increasing CO2 concentrations. The effect of increasing atmospheric CO2 concentration on antioxidant activity of ethanol extracts were light intensity dependent. The implications of these findings are discussed in the context of traditional plant antioxidants including vitamin C and the major onion flavonoid quercetin.

  12. Source limitation of carbon gas emissions in high-elevation mountain streams and lakes

    Science.gov (United States)

    Crawford, John T.; Dornblaser, Mark M.; Stanley, Emily H.; Clow, David W.; Striegl, Robert G.

    2015-01-01

    Inland waters are an important component of the global carbon cycle through transport, storage, and direct emissions of CO2 and CH4 to the atmosphere. Despite predictions of high physical gas exchange rates due to turbulent flows and ubiquitous supersaturation of CO2—and perhaps also CH4—patterns of gas emissions are essentially undocumented for high mountain ecosystems. Much like other headwater networks around the globe, we found that high-elevation streams in Rocky Mountain National Park, USA, were supersaturated with CO2 during the growing season and were net sources to the atmosphere. CO2concentrations in lakes, on the other hand, tended to be less than atmospheric equilibrium during the open water season. CO2 and CH4 emissions from the aquatic conduit were relatively small compared to many parts of the globe. Irrespective of the physical template for high gas exchange (high k), we found evidence of CO2 source limitation to mountain streams during the growing season, which limits overall CO2emissions. Our results suggest a reduced importance of aquatic ecosystems for carbon cycling in high-elevation landscapes having limited soil development and high CO2 consumption via mineral weathering.

  13. Effect of High Phytase Inclusion Rates on Performance of Broilers Fed Diets Not Severely Limited in Available Phosphorus

    Directory of Open Access Journals (Sweden)

    T. T. dos Santos

    2013-02-01

    Full Text Available Phytate is not only an unavailable source of phosphorus (P for broilers but it also acts as an anti-nutrient, reducing protein and mineral absorption, increasing endogenous losses and reducing broiler performance. The objective of this study was to investigate the anti-nutritional effects of phytate by including high levels of phytase in diets not severely limited in available P. A total of 768 male Arbor Acres broilers were distributed in six treatments of eight replicate pens of 16 birds each consisting of a positive control diet (PC, positive control with 500 FTU/kg phytase, negative control (NC diet with lower available P and calcium (Ca levels and the same NC diet with 500, 1,000 or 1,500 FTU/kg phytase. Body weight gain (BWG, feed intake (FI, feed conversion ratio (FCR and mortality were determined at 21 and 35 d of age while foot ash was determined in four birds per pen at 21 d of age. FI, FCR and foot ash where not affected by the lower mineral diets at 21 d of age nor by the enzyme inclusion but broilers fed lower Ca and available P diets had lower BWG. At 35 d of age no difference was observed between broilers fed the positive or NC diets but broilers fed 500, 1,000 and 1,500 FTU/kg on top of the NC diet had better FCR than broilers fed the positive control diet. When compared to birds fed a diet adequate in P, birds fed the same diet included with 500, 1,000 and 1,500 FTU/kg of phytase in marginally deficient available P and Ca diets had an improvement of performance. These results support the concept that hydrolysing phytate and reducing the anti-nutritional effects of phytate improves bird performance on marginally deficient diets that were not covering the P requirement of birds.

  14. Maximum total organic carbon limits at different DWPF melter feed maters (U)

    International Nuclear Information System (INIS)

    Choi, A.S.

    1996-01-01

    The document presents information on the maximum total organic carbon (TOC) limits that are allowable in the DWPF melter feed without forming a potentially flammable vapor in the off-gas system were determined at feed rates varying from 0.7 to 1.5 GPM. At the maximum TOC levels predicted, the peak concentration of combustible gases in the quenched off-gas will not exceed 60 percent of the lower flammable limit during a 3X off-gas surge, provided that the indicated melter vapor space temperature and the total air supply to the melter are maintained. All the necessary calculations for this study were made using the 4-stage cold cap model and the melter off-gas dynamics model. A high-degree of conservatism was included in the calculational bases and assumptions. As a result, the proposed correlations are believed to by conservative enough to be used for the melter off-gas flammability control purposes

  15. Nutrient amendment does not increase mineralisation of sequestered carbon during incubation of a nitrogen limited mangrove soil

    KAUST Repository

    Keuskamp, Joost A.

    2013-02-01

    Mangrove forests are sites of intense carbon and nutrient cycling, which result in soil carbon sequestration on a global scale. Currently, mangrove forests receive increasing quantities of exogenous nutrients due to coastal development. The present paper quantifies the effects of nutrient loading on microbial growth rates and the mineralisation of soil organic carbon (SOC) in two mangrove soils contrasting in carbon content. An increase in SOC mineralisation rates would lead to the loss of historically sequestered carbon and an enhanced CO2 release from these mangrove soils.In an incubation experiment we enriched soils from Avicennia and Rhizophora mangrove forests bordering the Red Sea with different combinations of nitrogen, phosphorus and glucose to mimic the effects of wastewater influx. We measured microbial growth rates as well as carbon mineralisation rates in the natural situation and after enrichment. The results show that microbial growth is energy limited in both soils, with nitrogen as a secondary limitation. Nitrogen amendment increased the rate at which labile organic carbon was decomposed, while it decreased SOC mineralisation rates. Such an inhibitory effect on SOC mineralisation was not found for phosphorus enrichment.Our data confirm the negative effect of nitrogen enrichment on the mineralisation of recalcitrant carbon compounds found in other systems. Based on our results it is not to be expected that nutrient enrichment by itself will cause degradation of historically sequestered soil organic carbon in nitrogen limited mangrove forests. © 2012 Elsevier Ltd.

  16. In situ nitrate from groundwater using freely available carbon material at an industrially polluted site

    CSIR Research Space (South Africa)

    Israel, S

    2011-09-01

    Full Text Available concentrations, nitrate in drinking water can be toxic to infants and young animals. In situ treatment could be a robust and effective technique for removal of nitrate, iron and manganese....

  17. Impacts of vinasse and methods of sugarcane harvesting on the availability of K and carbon stock of an Argisol

    Directory of Open Access Journals (Sweden)

    Claudinei Alberto Cardin

    2016-02-01

    Full Text Available ABSTRACT Soils of tropical regions are more weathered and in need of conservation managements to maintain and improve the quality of its components. The objective of this study was to evaluate the availability of K, the organic matter content and the stock of total carbon of an Argisol after vinasse application and manual and mechanized harvesting of burnt and raw sugarcane, in western São Paulo.The data collection was done in the 2012/2013 harvest, in a bioenergy company in Presidente Prudente/SP. The research was arranged out following a split-plot scheme in a 5x5 factorial design, characterized by four management systems: without vinasse application and harvest without burning; with vinasse application and harvest without burning; with vinasse application and harvest after burning; without vinasse application and harvest after burning; plus native forest, and five soil sampling depths (0-10 10-20, 20-30, 30-40, 40-50 cm, with four replications. In each treatment, the K content in the soil and accumulated in the remaining dry biomass in the area, the levels of organic matter, organic carbon and soil carbon stock were determined. The mean values were compared by Tukey test. The vinasse application associated with the harvest without burning increased the K content in soil layers up to 40 cm deep. The managements without vinasse application and manual harvest after burning, and without vinasse application with mechanical harvesting without burning did not increase the levels of organic matter, organic carbon and stock of total soil organic carbon, while the vinasse application and harvest after burning and without burning increased the levels of these attributes in the depth of 0-10 cm.

  18. Nitrogen availability drives priming effect by altering microbial carbon-use efficiency after permafrost thaw

    Science.gov (United States)

    Chen, L.; Liu, L.; Zhang, Q.; Mao, C.; Liu, F.; Yang, Y.

    2017-12-01

    Enhanced vegetation growth can potentially aggravate soil C loss by accelerating the decomposition of soil organic matter (SOM) ("priming effect"), thereby reinforcing the positive C-climate feedback in permafrost ecosystems. However, the degree to which priming effect alters permafrost C dynamics is expected to be modified by nitrogen (N) availability after permafrost thaw. Despite this recognition, experimental evidence for the linkage between priming effect and post-thaw N availability is still lacking. Particularly, the microbial mechanisms involved remain unknown. Here, using a thermokarst-induced natural N gradient combined with an isotope-labeled glucose and N addition experiment, we presented a strong linkage between soil N availability and priming effect in Tibetan permafrost. We observed that the magnitude of priming effect along the thaw gradient was negatively associated with soil total dissolved nitrogen (TDN) concentration. This negative effect of post-thaw N availability was further proved by a sharply reduced priming effect following mineral N supply. These two lines of evidence jointly illustrated that the priming effect along the thaw chronosequence was controlled by N availability, supporting the `N mining theory'. In contrast to the prevailing assumption, this N-regulated priming effect was independent from changes in C- or N-acquiring enzyme activities, but positively associated with the change in metabolic quotients (△SOM-qCO2), highlighting that decreased microbial metabolism efficiency rather than increased enzyme activities account for greater priming effect under reduced N availability. Taken together, these findings demonstrate that C dynamics in melting permafrost largely depends on post-thaw N availability due to its effect of retarding SOM mineralization. This C-N interaction and the relevant microbial metabolic efficiency should be considered in Earth System Models for a better understanding of soil C dynamics after permafrost thaw.

  19. Challenges in the repair of large abdominal wall hernias in Nigeria: review of available options in resource limited environments.

    Science.gov (United States)

    Ezeome, E R; Nwajiobi, C E

    2010-06-01

    To evaluate the challenges and outcome of management of large abdominal wall hernias in a resource limited environment and highlight the options available to surgeons in similar conditions. A review of prospectively collected data on large abdominal wall hernias managed between 2003 and 2009. University of Nigeria Teaching Hospital, Enugu, Nigeria and surrounding hospitals. Patients with hernias more than 4 cm in their largest diameter, patients with closely sited multiple hernias or failed previous repairs and in whom the surgeon considers direct repair inappropriate. Demographics of patients with large hernias, methods of hernia repair, recurrences, early and late complications following the repair. There were 41 patients, comprising 28 females and 13 males with ages 14 - 73 years. Most (53.7%) were incisional hernias. Gynecological surgeries (66.7%) were the most common initiating surgeries. Fifteen of the patients (36.6%) have had failed previous repairs, 41.5% were obese, five patients presented with intestinal obstruction. Thirty nine of the hernias were repaired with prolene mesh, one with composite mesh and one by danning technique. Most of the patients had extra peritoneal mesh placement. Three patients needed ventilator support. After a mean follow up of 18.6 months, there was a single failed repair. Two post op deaths were related to respiratory distress. There were 12 wound infection and 8 superficial wound dehiscence, all of which except one resolved with dressing. One reoperation was done following mesh infection and extrusion. Large abdominal wall hernia repair in resource limited environments present several challenges with wound infection and respiratory distress being the most notable. Surgeons who embark on it in these environments must be prepared t o secure the proper tissue replacement materials and have adequate ventilation support.

  20. Factors controlling Eucalyptus productivity: How water availability and stand structure alter production and carbon allocation

    Science.gov (United States)

    Michael G. Ryan; Jose Luiz Stape; Dan Binkley; Sebastiao Fonseca; Rodolfo A. Loos; Ernesto N. Takahashi; Claudio R. Silva; Sergio R. Silva; Rodrigo E. Hakamada; Jose Mario Ferreira; Augusto M. N. Lima; Jose Luiz Gava; Fernando P. Leite; Helder B. Andrade; Jacyr M. Alves; Gualter G. C. Silva

    2010-01-01

    Wood production varies substantially with resource availability, and the variation in wood production can result from several mechanisms: increased photosynthesis, and changes in partitioning of photosynthesis to wood production, belowground flux, foliage production or respiration. An understanding of the mechanistic basis for patterns in wood production...

  1. Nutrient availability and the ultimate control of the biological carbon pump in the western tropical South Pacific Ocean

    Science.gov (United States)

    Moutin, Thierry; Wagener, Thibaut; Caffin, Mathieu; Fumenia, Alain; Gimenez, Audrey; Baklouti, Melika; Bouruet-Aubertot, Pascale; Pujo-Pay, Mireille; Leblanc, Karine; Lefevre, Dominique; Helias Nunige, Sandra; Leblond, Nathalie; Grosso, Olivier; de Verneil, Alain

    2018-05-01

    Surface waters (0-200 m) of the western tropical South Pacific (WTSP) were sampled along a longitudinal 4000 km transect (OUTPACE cruise, DOI: 10.17600/15000900) during the austral summer (stratified) period (18 February to 3 April 2015) between the Melanesian Archipelago (MA) and the western part of the SP gyre (WGY). Two distinct areas were considered for the MA, the western MA (WMA), and the eastern MA (EMA). The main carbon (C), nitrogen (N), and phosphorus (P) pools and fluxes provide a basis for the characterization of the expected trend from oligotrophy to ultra-oligotrophy, and the building of first-order budgets at the daily and seasonal timescales (using climatology). Sea surface chlorophyll a well reflected the expected oligotrophic gradient with higher values obtained at WMA, lower values at WGY, and intermediate values at EMA. As expected, the euphotic zone depth, the deep chlorophyll maximum, and nitracline depth deepen from west to east. Nevertheless, phosphaclines and nitraclines did not match. The decoupling between phosphacline and nitracline depths in the MA allows for excess P to be locally provided in the upper water by winter mixing. We found a significant biological soft tissue carbon pump in the MA sustained almost exclusively by dinitrogen (N2) fixation and essentially controlled by phosphate availability in this iron-rich environment. The MA appears to be a net sink for atmospheric CO2, while the WGY is in quasi-steady state. We suggest that the necessary excess P, allowing the success of nitrogen fixers and subsequent carbon production and export, is mainly brought to the upper surface by local deep winter convection at an annual timescale rather than by surface circulation. While the origin of the decoupling between phosphacline and nitracline remains uncertain, the direct link between local P upper water enrichment, N2 fixation, and organic carbon production and export, offers a possible shorter timescale than previously thought between

  2. Availability of endogenous peptides limits expression of an M3a-Ld major histocompatibility complex class I chimera

    Science.gov (United States)

    1994-01-01

    Taking advantage of our understanding of the peptide specificity of the major histocompatibility complex class I-b molecule M3a, we sought to determine why these molecules are poorly represented on the cell surface. To this end we constructed a chimeric molecule with the alpha 1 and alpha 2 domains of M3a and alpha 3 of Ld thereby allowing use of available monoclonal antibodies to quantify surface expression. Transfected, but not control, B10.CAS2 (H-2M3b) cells were lysed readily by M3a-restricted monoclonal cytotoxic T lymphocytes. Thus, the chimera bound, trafficked, and presented endogenous mitochondrial peptides. However, despite high levels of M3a-Ld mRNA, transfectants were negative by surface staining. This finding was consistent with inefficient trafficking to the cell surface. Incubation at 26 degrees C, thought to permit trafficking of unoccupied heavy (H) chains, resulted in detectable cell surface expression of chimeric molecules. Incubation with exogenous peptide at 26 degrees C (but not at 37 degrees C) greatly enhanced expression of M3a-Ld molecules in a dose- dependent manner, suggesting stabilization of unoccupied molecules. Stable association of beta 2-microglobulin with the chimeric H chain was observed in labeled cell lysates only in the presence of exogenous specific peptide, indicating that peptide is required for the formation of a ternary complex. These results indicate that surface expression of M3a-Ld is limited largely by the steady-state availability of endogenous peptides. Since most known M3a-binding peptides are N- formylated, native M3a may normally be expressed at high levels only during infection by intracellular bacteria. PMID:8270862

  3. Effect of light and nutrient availability on the release of dissolved organic carbon (DOC) by Caribbean turf algae.

    Science.gov (United States)

    Mueller, Benjamin; den Haan, Joost; Visser, Petra M; Vermeij, Mark J A; van Duyl, Fleur C

    2016-03-22

    Turf algae increasingly dominate benthic communities on coral reefs. Given their abundance and high dissolved organic carbon (DOC) release rates, turf algae are considered important contributors to the DOC pool on modern reefs. The release of photosynthetically fixed carbon as DOC generally, but not always, increases with increased light availability. Nutrient availability was proposed as an additional factor to explain these conflicting observations. To address this proposed but untested hypothesis, we documented the interactive contributions of light and nutrient availability on the release of DOC by turf algae. DOC release rates and oxygen production were quantified in incubation experiments at two light levels (full and reduced light) and two nutrient treatments (natural seawater and enriched seawater). In natural seawater, DOC release at full light was four times higher than at reduced light. When nutrients were added, DOC release rates at both light levels were similar to the natural seawater treatment at full light. Our results therefore show that low light in combination with low nutrient availability reduces the release of DOC by turf algae and that light and nutrient availability interactively determine DOC release rates by this important component of Caribbean reef communities.

  4. Transcriptomic Analysis of Responses to Imbalanced Carbon: Nitrogen Availabilities in Rice Seedlings.

    Directory of Open Access Journals (Sweden)

    Aobo Huang

    Full Text Available The internal C:N balance must be tightly controlled for the normal growth and development of plants. However, the underlying mechanisms, by which plants sense and balance the intracellular C:N status correspondingly to exogenous C:N availabilities remain elusive. In this study, we use comparative gene expression analysis to identify genes that are responsive to imbalanced C:N treatments in the aerial parts of rice seedlings. Transcripts of rice seedlings treated with four C:N availabilities (1:1, 1:60, 60:1 and 60:60 were compared and two groups of genes were classified: high C:low N responsive genes and low C:high N responsive genes. Our analysis identified several functional correlated genes including chalcone synthase (CHS, chlorophyll a-b binding protein (CAB and other genes that are implicated in C:N balancing mechanism, such as alternative oxidase 1B (OsAOX1B, malate dehydrogenase (OsMDH and lysine and histidine specific transporter 1 (OsLHT1. Additionally, six jasmonate synthetic genes and key regulatory genes involved in abiotic and biotic stresses, such as OsMYB4, autoinhibited calcium ATPase 3 (OsACA3 and pleiotropic drug resistance 9 (OsPDR9, were differentially expressed under high C:low N treatment. Gene ontology analysis showed that high C:low N up-regulated genes were primarily enriched in fatty acid biosynthesis and defense responses. Coexpression network analysis of these genes identified eight jasmonate ZIM domain protein (OsJAZ genes and several defense response related regulators, suggesting that high C:low N status may act as a stress condition, which induces defense responses mediated by jasmonate signaling pathway. Our transcriptome analysis shed new light on the C:N balancing mechanisms and revealed several important regulators of C:N status in rice seedlings.

  5. Application of the dose limitation system to the control of carbon-14 releases from heavy-water-moderated reactors

    International Nuclear Information System (INIS)

    Beninson, D.; Gonzalez, A.J.

    1982-01-01

    Heavy-water-moderated reactors produce substantially more carbon-14 than light-water reactors. Applying the principles of the systems of dose limitation, the paper presents the rationale used for establishing the release limit for effluents containing this nuclide and for the decisions made regarding the effluent treatment in the third nuclear power station in Argentina. Production of carbon-14 in PHWR and the release routes are analysed in the light of the different effluent treatment possibilities. An optimization assessment is presented, taking into account effluent treatment and waste management costs, and the collective effective dose commitment due to the releases. The contribution of present carbon-14 releases to future individual doses is also analysed in the light of an upper bound for the contribution, representing a fraction of the individual dose limits. The paper presents the resulting requirements for the effluent treatment regarding carbon-14 and the corresponding regulatory aspects used in Argentina. (author)

  6. Identification of aquatically available carbon from algae through solution-state NMR of whole (13)C-labelled cells.

    Science.gov (United States)

    Akhter, Mohammad; Dutta Majumdar, Rudraksha; Fortier-McGill, Blythe; Soong, Ronald; Liaghati-Mobarhan, Yalda; Simpson, Myrna; Arhonditsis, George; Schmidt, Sebastian; Heumann, Hermann; Simpson, André J

    2016-06-01

    Green algae and cyanobacteria are primary producers with profound impact on food web functioning. Both represent key carbon sources and sinks in the aquatic environment, helping modulate the dissolved organic matter balance and representing a potential biofuel source. Underlying the impact of algae and cyanobacteria on an ecosystem level is their molecular composition. Herein, intact (13)C-labelled whole cell suspensions of Chlamydomonas reinhardtii, Chlorella vulgaris and Synechocystis were studied using a variety of 1D and 2D (1)H/(13)C solution-state nuclear magnetic resonance (NMR) spectroscopic experiments. Solution-state NMR spectroscopy of whole cell suspensions is particularly relevant as it identifies species that are mobile (dissolved or dynamic gels), 'aquatically available' and directly contribute to the aquatic carbon pool upon lysis, death or become a readily available food source on consumption. In this study, a wide range of metabolites and structural components were identified within the whole cell suspensions. In addition, significant differences in the lipid/triacylglyceride (TAG) content of green algae and cyanobacteria were confirmed. Mobile species in algae are quite different from those in abundance in 'classic' dissolved organic matter (DOM) indicating that if algae are major contributors to DOM, considerable selective preservation of minor components (e.g. sterols) or biotransformation would have to occur. Identifying the metabolites and dissolved components within algal cells by NMR permits future studies of carbon transfer between species and through the food chain, whilst providing a foundation to better understand the role of algae in the formation of DOM and the sequestration/transformation of carbon in aquatic environments.

  7. Limited transport of functionalized multi-walled carbon nanotubes in two natural soils

    International Nuclear Information System (INIS)

    Kasel, Daniela; Bradford, Scott A.; Šimůnek, Jiří; Pütz, Thomas; Vereecken, Harry; Klumpp, Erwin

    2013-01-01

    Column experiments were conducted in undisturbed and in repacked soil columns at water contents close to saturation (85–96%) to investigate the transport and retention of functionalized 14 C-labeled multi-walled carbon nanotubes (MWCNT) in two natural soils. Additionally, a field lysimeter experiment was performed to provide long-term information at a larger scale. In all experiments, no breakthrough of MWCNTs was detectable and more than 85% of the applied radioactivity was recovered in the soil profiles. The retention profiles exhibited a hyper-exponential shape with greater retention near the column or lysimeter inlet and were successfully simulated using a numerical model that accounted for depth-dependent retention. In conclusion, results indicated that the soils acted as a strong sink for MWCNTs. Little transport of MWCNTs is therefore likely to occur in the vadose zone, and this implies limited potential for groundwater contamination in the investigated soils. -- Highlights: •Investigation of undisturbed soil columns and lysimeter. •Transport experiments under water-unsaturated conditions. •Retention profiles were measured and numerically modeled. •Complete retention of MWCNT in undisturbed and repacked soil columns. -- In undisturbed columns and a lysimeter study, complete retention of functionalized multi-walled carbon nanotubes was found in two soils at environmentally relevant conditions

  8. Spot Size Limited Carbon Propellant Characterization for Efficient High Isp Laser Propulsion

    International Nuclear Information System (INIS)

    Uchida, Shigeaki; Shimada, Yoshinori; Hashimoto, Kazuhisa; Yamaura, Michiteru; Birou, Tomoya; Yoshida, Minoru

    2005-01-01

    Laser propulsion has very unique advantage of producing exhausting gas (ions) of very high velocity. Specific impulse from laser plasma could easily exceed 10,000 seconds that reduce the current propellant consumption rate on space born thrusters significantly. For efficient propellant usage, it is desirable that the exhaust plasma has rather narrow velocity distribution of fast ions. In order to accomplish the requirements, thermal conduction and neutral particle losses at and vicinity of the laser heated region have to be eliminated. A concept of spot size limited propellant shape has been proposed and tested in terms of the effects of the loss reduction. Ion and neutral particle measurements from laser plasmas produced on the above mentioned carbon targets are used to characterize the performance of the propellant

  9. Pore diffusion limits removal of monochloramine in treatment of swimming pool water using granular activated carbon.

    Science.gov (United States)

    Skibinski, Bertram; Götze, Christoph; Worch, Eckhard; Uhl, Wolfgang

    2018-04-01

    Overall apparent reaction rates for the removal of monochloramine (MCA) in granular activated carbon (GAC) beds were determined using a fixed-bed reactor system and under conditions typical for swimming pool water treatment. Reaction rates dropped and quasi-stationary conditions were reached quickly. Diffusional mass transport in the pores was shown to be limiting the overall reaction rate. This was reflected consistently in the Thiele modulus, in the effect of temperature, pore size distribution and of grain size on the reaction rates. Pores <2.5 times the diameter of the monochloramine molecule were shown to be barely accessible for the monochloramine conversion reaction. GACs with a significant proportion of large mesopores were found to have the highest overall reactivity for monochloramine removal. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. The difficulties in establishing an occupational exposure limit for carbon nanotubes

    DEFF Research Database (Denmark)

    Ellenbecker, M.; Tsai, .S-J.; Jacobs, M.

    2018-01-01

    Concern over the health effects from the inhalation of carbon nanotubes (CNTs) has been building for some time, and adverse health effects found in animal studies include acute and chronic respiratory damage, cardiac inflammation, and cancer including mesothelioma, heretofore only associated...... with asbestos exposure. The strong animal evidence of toxicity requires that the occupational hygiene community develops strategies for reducing or eliminating worker exposures to CNTs; part of this strategy involves the setting of occupational exposure limits (OELs) for CNTs. A number of government agencies...... concerning the potential adverse health effects from CNT inhalation, the development of more nuanced OELs that reflect the complex nature of CNT exposure, a broader discussion of these issues among all interested parties, and further research into important unanswered questions including optimum methods...

  11. Nitrogen Availability Dampens the Positive Impacts of CO2 Fertilization on Terrestrial Ecosystem Carbon and Water Cycles

    Science.gov (United States)

    He, Liming; Chen, Jing M.; Croft, Holly; Gonsamo, Alemu; Luo, Xiangzhong; Liu, Jane; Zheng, Ting; Liu, Ronggao; Liu, Yang

    2017-11-01

    The magnitude and variability of the terrestrial CO2 sink remain uncertain, partly due to limited global information on ecosystem nitrogen (N) and its cycle. Without N constraint in ecosystem models, the simulated benefits from CO2 fertilization and CO2-induced increases in water use efficiency (WUE) may be overestimated. In this study, satellite observations of a relative measure of chlorophyll content are used as a proxy for leaf photosynthetic N content globally for 2003-2011. Global gross primary productivity (GPP) and evapotranspiration are estimated under elevated CO2 and N-constrained model scenarios. Results suggest that the rate of global GPP increase is overestimated by 85% during 2000-2015 without N limitation. This limitation is found to occur in many tropical and boreal forests, where a negative leaf N trend indicates a reduction in photosynthetic capacity, thereby suppressing the positive vegetation response to enhanced CO2 fertilization. Based on our carbon-water coupled simulations, enhanced CO2 concentration decreased stomatal conductance and hence increased WUE by 10% globally over the 1982 to 2015 time frame. Due to increased anthropogenic N application, GPP in croplands continues to grow and offset the weak negative trend in forests due to N limitation. Our results also show that the improved WUE is unlikely to ease regional droughts in croplands because of increases in evapotranspiration, which are associated with the enhanced GPP. Although the N limitation on GPP increase is large, its associated confidence interval is still wide, suggesting an urgent need for better understanding and quantification of N limitation from satellite observations.

  12. Are variations in heterotrophic soil respiration related to changes in substrate availability and microbial biomass carbon in the subtropical forests?

    Science.gov (United States)

    Wei, Hui; Chen, Xiaomei; Xiao, Guoliang; Guenet, Bertrand; Vicca, Sara; Shen, Weijun

    2015-12-16

    Soil temperature and moisture are widely-recognized controlling factors on heterotrophic soil respiration (Rh), although they often explain only a portion of Rh variability. How other soil physicochemical and microbial properties may contribute to Rh variability has been less studied. We conducted field measurements on Rh half-monthly and associated soil properties monthly for two years in four subtropical forests of southern China to assess influences of carbon availability and microbial properties on Rh. Rh in coniferous forest was significantly lower than that in the other three broadleaf species-dominated forests and exhibited obvious seasonal variations in the four forests (P forests. The quantity and decomposability of dissolved organic carbon (DOC) were significantly important to Rh variations, but the effect of DOC content on Rh was confounded with temperature, as revealed by partial mantel test. Microbial biomass carbon (MBC) was significantly related to Rh variations across forests during the warm season (P = 0.043). Our results suggest that DOC and MBC may be important when predicting Rh under some conditions, and highlight the complexity by mutual effects of them with environmental factors on Rh variations.

  13. Are variations in heterotrophic soil respiration related to changes in substrate availability and microbial biomass carbon in the subtropical forests?

    Science.gov (United States)

    Wei, Hui; Chen, Xiaomei; Xiao, Guoliang; Guenet, Bertrand; Vicca, Sara; Shen, Weijun

    2015-01-01

    Soil temperature and moisture are widely-recognized controlling factors on heterotrophic soil respiration (Rh), although they often explain only a portion of Rh variability. How other soil physicochemical and microbial properties may contribute to Rh variability has been less studied. We conducted field measurements on Rh half-monthly and associated soil properties monthly for two years in four subtropical forests of southern China to assess influences of carbon availability and microbial properties on Rh. Rh in coniferous forest was significantly lower than that in the other three broadleaf species-dominated forests and exhibited obvious seasonal variations in the four forests (P < 0.05). Temperature was the primary factor influencing the seasonal variability of Rh while moisture was not in these humid subtropical forests. The quantity and decomposability of dissolved organic carbon (DOC) were significantly important to Rh variations, but the effect of DOC content on Rh was confounded with temperature, as revealed by partial mantel test. Microbial biomass carbon (MBC) was significantly related to Rh variations across forests during the warm season (P = 0.043). Our results suggest that DOC and MBC may be important when predicting Rh under some conditions, and highlight the complexity by mutual effects of them with environmental factors on Rh variations. PMID:26670822

  14. Temperature and ionic strength influences on actinide(VI)/(V) redox potentials for carbonate limiting complexes

    International Nuclear Information System (INIS)

    Capdevila, H.; Vitorge, P.

    1998-01-01

    Actinide behaviour was studied in two limiting aqueous solutions: acidic and carbonate. Cyclic voltametry was validated with well-known U redox system. SIT was used to account for I influence. Taylor's series expansions to the second order were used to account for T influence. Redox potentials of actinide couples had previously been measured in non complexing media. The above data treatments give standard values for redox potential E 0 , for the corresponding entropy ΔS 0 , enthalpy ΔH 0 and heat capacity ΔC p 0 changes, and also for the corresponding excess values (i.e. the variation of these thermodynamic constants with ionic strength). This methodology was here used in carbonate media to measure the potential of the redox couple PuO 2 (CO 3 ) 3 4- /PuO 2 (CO 3 ) 3 5- from 5 to 70 degC and from I = 0.5 to 4.5 M in Na 2 CO 3 , NaClO 4 media. Experimental details and full results are given for Pu. Only final results are given for Np. Previous and/or published data for U and Am are discussed. E and ΔS variations with T or I were enough to be measured. The values obtained for the fitted SIT coefficients Δε, and for ΔS and ΔCp are similar for U, Np and Pu redox reactions. Using this analogy for Am missing data is discussed. β 3 V /β 3 VI formation constant ratio of the carbonate limiting complexes were deduced from the potential shift from complexing to non complexing media for the Actinide(VI)/Actinide(V) redox couples. β 3 V (U and Pu) and β 3 VI (Np) were finally proposed using published β3 VI (U and Pu) and β 3 V (Np). For Am, this data treatment was used to discuss the AmO 2 2+ / AmO 2 + redox potential

  15. Potential and limitations of bio-energy options for low carbon transitions

    International Nuclear Information System (INIS)

    Bibas, Ruben; Mejean, Aurelie

    2012-01-01

    Sustaining low CO 2 emission pathways to 2100 may rely on electricity production from biomass. We analyze the effect of the availability of biomass resources and technologies with and without carbon capture and storage within a general equilibrium framework. Biomass technologies are introduced into the electricity module of the hybrid general equilibrium model Imaclim-R. We assess the robustness of this technology, with and without carbon capture and storage, as a way of reaching the RCP 3.7 stabilization target. The impact of a uniform CO 2 tax on energy prices, investments and the structure of the electricity mix is examined. World GDP growth is affected by the absence of the CCS or biomass options, and biomass is shown to be a possible technological answer to the absence of CCS. As the use of biomass on a large scale might prove unsustainable, we illustrate early action as a strategy to reduce the need for biomass and enhance economic growth in the long term. (authors)

  16. [Carbon monoxide tests in a steady state. Uptake and transfer capacity, normal values and lower limits].

    Science.gov (United States)

    Ramonatxo, M; Préfaut, C; Guerrero, H; Moutou, H; Bansard, X; Chardon, G

    1982-01-01

    The aim of this study was to establish data which would best demonstrate the variations of different tests using Carbon Monoxide as a tracer gas (total and partial functional uptake coefficient and transfer capacity) to establish mean values and lower limits of normal of these tests. Multivariate statistical analysis was used; in the first stage a connection was sought between the fractional uptake coefficient (partial and total) to other parameters, comparing subjects and data. In the second stage the comparison was refined by eliminating the least useful data, trying, despite a small loss of material, to reveal the most important connections, linear or otherwise. The fractional uptake coefficients varied according to sex, also the variation of the partial alveolar-expired fractional uptake equivalent (DuACO) was largely a function of respiratory rate and tidal volume. The alveolar-arterial partial fractional uptake equivalent (DuaCO) depended more on respiratory frequency and age. Finally the total fractional uptake coefficient (DuCO) and the transfer capacity corrected per liter of ventilation (TLCO/V) were functions of these parameters. The last stage of this work, after taking account of the statistical observations consistent with the facts of these physiological hypotheses led to a search for a better way of approaching the laws linking the collected data to the fractional uptake coefficient. The lower limits of normal were arbitrarily defined, separating those 5% of subjects deviating most strongly from the mean. As a result, the relationship between the lower limit of normal and the theoretical mean value was 90% for the partial and total fractional uptake coefficient and 70% for the transfer capacity corrected per liter of ventilation.

  17. Upper-airway flow limitation and transcutaneous carbon dioxide during sleep in normal pregnancy.

    Science.gov (United States)

    Rimpilä, Ville; Jernman, Riina; Lassila, Katariina; Uotila, Jukka; Huhtala, Heini; Mäenpää, Johanna; Polo, Olli

    2017-08-01

    Sleep during pregnancy involves a physiological challenge to provide sufficient gas exchange to the fetus. Enhanced ventilatory responses to hypercapnia and hypoxia may protect from deficient gas exchange, but sleep-disordered breathing (SDB) may predispose to adverse events. The aim of this study was to analyze sleep and breathing in healthy pregnant women compared to non-pregnant controls, with a focus on CO 2 changes and upper-airway flow limitation. Healthy women in the third trimester and healthy non-pregnant women with normal body mass index (BMI) were recruited for polysomnography. Conventional analysis of sleep and breathing was performed. Transcutaneous carbon dioxide (TcCO 2 ) was determined for each sleep stage. Flow-limitation was analyzed using the flattening index and TcCO 2 values were recorded for every inspiration. Eighteen pregnant women and 12 controls were studied. Pregnancy was associated with shorter sleep duration and more superficial sleep. Apnea-hypopnea index, arterial oxyhemoglobin desaturation, flow-limitation, snoring or periodic leg movements were similar in the two groups. Mean SaO 2 and minimum SaO 2 were lower and average heart rate was higher in the pregnant group. TcCO 2 levels did not differ between groups but variance of TcCO 2 was smaller in pregnant women during non-rapid eye movement (NREM). TcCO 2 profiles showed transient TcCO 2 peaks, which seem specific to pregnancy. Healthy pregnancy does not predispose to SDB. Enhanced ventilatory control manifests as narrowing threshold of TcCO 2 between wakefulness and sleep. Pregnant women have a tendency for rapid CO 2 increases during sleep which might have harmful consequences if not properly compensated. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Contribution of trees and grasses to ecosystem fluxes of water, carbon, and energy throughout the seasons under different nutrient availability

    Science.gov (United States)

    El-Madany, T. S.; Migliavacca, M.; Perez-Priego, O.; Luo, Y.; Moreno, G.; Carrara, A.; Kolle, O.; Reichstein, M.

    2017-12-01

    In semi-arid savanna type ecosystems, the carbon and water cycle are closely related to each other. Water availability is the main driver for the development and phenology of the vegetation, especially for annual plants. Depending on tree density, nutrient availability and species the contribution of the tree- and the herbaceous layer to ecosystem fluxes can vary substantially. We present data from an ecosystem scale nutrient manipulation experiment within a Mediterranean savanna type ecosystem which is used for cattle. The footprint areas of two out of three ecosystem eddy co-variance (EC) towers were fertilized with nitrogen (NT) and nitrogen plus phosphorous (NPT) while the third one served as the control tower (CT). At each ecosystem EC-tower an additional herbaceous layer tower was installed that only sampled fluxes from the herbaceous layer. Under certain assumptions flux differences between the ecosystem EC and the herbaceous layer EC systems can be considered as the contribution of the trees to the ecosystem fluxes. Based on phenology of the herbaceous layer estimated through green-chromatic-coordinates from digital imagery the year was separated into spring, senescence, regreening, and winter. The focus of the analysis is (i) the evaluation of the method and how it works throughout the different seasons and (ii) the quantification of the contribution of trees and grasses to ecosystem fluxes of water, carbon, and energy under different environmental conditions and nutrient stoichiometry. The contribution of the trees to total ecosystem fluxes is variable in time. Especially, during the beginning of the senescence period high evapotranspiration rates and largest carbon uptake are measured while the contribution to sensible heat fluxes is largest during the end of the summer. During the regreening and winter the contribution of ET is relatively constant around 0.25 mm d-1. During the peak of the greenness ET and carbon flux of the herbaceous EC tower are

  19. Limited carbon storage in soil and litter of experimental forest plots under increased atmospheric CO2

    International Nuclear Information System (INIS)

    Schlesinger, W.H.; Lichter, J.

    2001-01-01

    The current rise in atmospheric CO 2 concentration is thought to be mitigated in part by carbon sequestration within forest ecosystems, where carbon can be stored in vegetation or soils. The storage of carbon in soils is determined by the fraction that is sequestered in persistent organic materials, such as humus. In experimental forest plots of loblolly pine (Pinus taeda) exposed to high CO 2 concentrations, nearly half of the carbon uptake is allocated to short-lived tissues, largely foliage. These tissues fall to the ground and decompose, normally contributing only a small portion of their carbon content to refractory soil humic materials. Such findings call into question the role of soils as long-term carbon sinks, and show the need for a better understanding of carbon cycling in forest soils. Here we report a significant accumulation of carbon in the litter layer of experimental forest plots after three years of growth at increased CO 2 concentrations (565 μ l 1 ). But fast turnover times of organic carbon in the litter layer (of about three years) appear to constrain the potential size of this carbon sink. Given the observation that carbon accumulation in the deeper mineral soil layers was absent, we suggest that significant, long-term net carbon sequestration in forest soils is unlikely. (author)

  20. Assessment of nitrogen and phosphorus flows in agricultural and urban systems in a small island under limited data availability

    NARCIS (Netherlands)

    Firmansyah, I.; Spiller, M.; Ruijter, De F.J.; Carsjens, G.J.; Zeeman, G.

    2017-01-01

    Nitrogen (N) and phosphorus (P) are two essential macronutrients required in agricultural production. The
    major share of this production relies on chemical fertilizer that requires energy and relies on limited resources
    (P). Since these nutrients are lost to the environment, there is a need

  1. 40 CFR 437.44 - Effluent limitations attainable by the application of the best available technology economically...

    Science.gov (United States)

    2010-07-01

    ... Lead Mercury Nickel Silver Tin Titanium Vanadium Zinc (2) The in-plant limitations that apply to metal... Pyridine 2,4,6-trichlorophenol Metal parameters Arsenic Cadmium Chromium Cobalt Copper Lead Mercury Tin...-Cresol p-Cresol n-Decane Fluoranthene n-Octadecane Phenol Pyridine 2,4,6-trichlorophenol Metal parameters...

  2. Interactive effect of reduced pollen availability and Varroa destructor infestation limits growth and protein content of young honey bees

    NARCIS (Netherlands)

    Dooremalen, van C.; Stam, E.; Gerritsen, L.J.M.; Cornelissen, B.; Steen, van der J.J.M.; Langevelde, van F.; Blacquiere, T.

    2013-01-01

    Varroa destructor in combination with one or more stressors, such as low food availability or chemical exposure, is considered to be one of the main causes for honey bee colony losses. We examined the inter-active effect of pollen availability on the protein content and body weight of young bees

  3. Nitrogen and phosphorous limitation reduces the effects of land use change on land carbon uptake or emission

    International Nuclear Information System (INIS)

    Wang, Ying-Ping; Zhang, Qian; Dai, Yongjiu; Pitman, Andrew J

    2015-01-01

    We used an Earth System Model that includes both nitrogen (N) and phosphorus (P) cycling to simulate the impacts of land-use and land-cover change (LULCC) for two representative concentration pathways (RCPs): a reforestation scenario (RCP4.5) and a deforestation scenario (RCP8.5). For each RCP, we performed simulations with and without LULCC using the carbon (C only) mode or including the full C, N and P cycles (CNP). We show, for the first time, that inclusion of N and P cycling reduces both the carbon uptake from reforestation in RCP4.5 and the carbon emission from deforestation in RCP8.5. Specifically, carbon-nutrient interaction reduces carbon uptake in RCP4.5 from 55 Pg C (C only) to 21 Pg C (CNP), or the emissions in RCP8.5 from 72 Pg C (C only) to 56 Pg C (CNP). Most of those reductions result from much weaker responses of net primary production to CO 2 fertilization and climate change when carbon-nutrient interaction is taken into account, as compared to C only simulations. Our results highlight the importance of including nutrient-carbon interaction in estimating the carbon benefit from reforestation and carbon loss from deforestation in a future world with higher CO 2 and a warmer climate. Because of the stronger nutrient limitation, carbon gain from reforestation in the temperate and boreal regions is much less than the carbon loss from deforestation in the subtropical and tropical regions from 2006 to 2100 for the two RCPs. Therefore protecting the existing subtropical and tropical forests is about twice as effective as planting new forests in the temperate and boreal regions for climate mitigation. (letter)

  4. Origin, concentration, availability and fate of dissolved organic carbon in coastal lagoons of the Rio de Janeiro State

    Directory of Open Access Journals (Sweden)

    Albert Luiz Suhett

    Full Text Available The coastal lagoons in the northern Rio de Janeiro State (Brazil present a wide gradient of dissolved organic carbon (DOC and water color, with the highest DOC concentrations reported in the literature for aquatic ecosystems. Thus, they represent a peculiar set of ecosystems for the study of the origin, processing and fate of DOC in inland waters. We reviewed data from 2 decades of studies on the carbon cycle in these coastal lagoons and discussed the fluctuations in the concentration and quality of DOC, factors affecting DOC microbial and photochemical degradation, CO2 emission, as well as the role of humic and non-humic carbon to the energy flow through the trophic chains. We show that DOC quality, not its quantity, determines the rates of photochemical and microbial degradation both seasonally (within system and spatially (among systems, with the exception of DOC photo-oxidation among lagoons, which is partially explained by DOC concentration at regional scale. In humic lagoons, there is a fairly predictable pattern of seasonal variation in DOC concentration associated to rainfall-induced inputs of allochthonous C. However, little is known about the exact timing of these allochthonous inputs and how they relate to the seasonal variation of DOC chemical properties (i.e. its quality. Depth-integrated photo-oxidation rates were less representative in highly humic lagoons, due to strong light attenuation in the water column. Nevertheless, the potential contribution of photo-oxidation and bacterial respiration to total CO2 efflux (~11% did not differ significantly when all lagoons were pooled together. Contrary to prevailing paradigms for humic waters, microalgae seem to be the main C source in humic lagoons, sustaining pelagic food webs through zooplankton, in spite of some contribution of allochthonous C. Thus, the predominant role of the microbial loop in the DOC recovery to food webs in such systems is to be questioned.

  5. Diurnal variation in the coupling of photosynthetic electron transport and carbon fixation in iron-limited phytoplankton in the NE subarctic Pacific

    Science.gov (United States)

    Schuback, Nina; Flecken, Mirkko; Maldonado, Maria T.; Tortell, Philippe D.

    2016-02-01

    Active chlorophyll a fluorescence approaches, including fast repetition rate fluorometry (FRRF), have the potential to provide estimates of phytoplankton primary productivity at an unprecedented spatial and temporal resolution. FRRF-derived productivity rates are based on estimates of charge separation in reaction center II (ETRRCII), which must be converted into ecologically relevant units of carbon fixation. Understanding sources of variability in the coupling of ETRRCII and carbon fixation provides physiological insight into phytoplankton photosynthesis and is critical for the application of FRRF as a primary productivity measurement tool. In the present study, we simultaneously measured phytoplankton carbon fixation and ETRRCII in the iron-limited NE subarctic Pacific over the course of a diurnal cycle. We show that rates of ETRRCII are closely tied to the diurnal cycle in light availability, whereas rates of carbon fixation appear to be influenced by endogenous changes in metabolic energy allocation under iron-limited conditions. Unsynchronized diurnal oscillations of the two rates led to 3.5-fold changes in the conversion factor between ETRRCII and carbon fixation (Kc / nPSII). Consequently, diurnal variability in phytoplankton carbon fixation cannot be adequately captured with FRRF approaches if a constant conversion factor is applied. Utilizing several auxiliary photophysiological measurements, we observed that a high conversion factor is associated with conditions of excess light and correlates with the increased expression of non-photochemical quenching (NPQ) in the pigment antenna, as derived from FRRF measurements. The observed correlation between NPQ and Kc / nPSII requires further validation but has the potential to improve estimates of phytoplankton carbon fixation rates from FRRF measurements alone.

  6. Changes in soil water availability in vineyards can be traced by the carbon and nitrogen isotope composition of dried wines.

    Science.gov (United States)

    Spangenberg, Jorge E; Zufferey, Vivian

    2018-04-13

    The grapevine is one of the most important edible fruit plants cultivated worldwide, and it is highly sensitive to changes in the soil water content. We studied the total carbon and nitrogen contents and stable isotope compositions (C/N WSR , δ 13 C WSR and δ 15 N WSR values) of the solid residues obtained by freeze-drying wines produced from two white grapevine cultivars (Vitis vinifera L. cv Chasselas and Petite Arvine) field grown under different soil water regimes while maintaining other climatic and ecopedological conditions identical. These experiments simulated the more frequent and extended climate change-induced periods of soil water shortage. The wines were from the 2009-2014 vintages, produced using the same vinification procedure. The plant water status, reflecting soil water availability, was assessed by the predawn leaf water potential (Ψ pd ), monitored in the field during the growing seasons. For both wine varieties, the δ 13 C WSR values are highly correlated with Ψ pd values and record the soil water availability set by soil water holding capacity, rainfall and irrigation water supply. These relationships were the same as those observed for the carbon isotope composition of fruit sugars (i.e., must sugars) and plant water status. In Chasselas wines, the nitrogen content and δ 15 N WSR values decreased with soil water deficit, indicating control of the flux of soil-water soluble nutrients into plants by soil water availability. Such a correlation was not found for Petite Arvine, probably due to different N-metabolism processes in this genetically atypical cultivar. The results presented in this study confirm and generalize what was previously found for red wine (Pinot noir); the carbon isotope composition of wine solid residues is a reliable indicator of the soil and the plant water status and thus can be used to trace back local climatic conditions in the vineyard's region. In most wines (except Petite Arvine) the C/N WSR and δ 15 N WSR

  7. The difficulties in establishing an occupational exposure limit for carbon nanotubes

    Science.gov (United States)

    Ellenbecker, M.; Tsai, S.-J.; Jacobs, M.; Riediker, M.; Peters, T.; Liou, S.; Avila, A.; FossHansen, S.

    2018-05-01

    Concern over the health effects from the inhalation of carbon nanotubes (CNTs) has been building for some time, and adverse health effects found in animal studies include acute and chronic respiratory damage, cardiac inflammation, and cancer including mesothelioma, heretofore only associated with asbestos exposure. The strong animal evidence of toxicity requires that the occupational hygiene community develops strategies for reducing or eliminating worker exposures to CNTs; part of this strategy involves the setting of occupational exposure limits (OELs) for CNTs. A number of government agencies and private entities have established OELs for CNTs; some are mass-based, while others rely on number concentration. We review these various proposed standards and discuss the pros and cons of each approach. We recommend that specific action be taken, including intensified outreach to employers and employees concerning the potential adverse health effects from CNT inhalation, the development of more nuanced OELs that reflect the complex nature of CNT exposure, a broader discussion of these issues among all interested parties, and further research into important unanswered questions including optimum methods to evaluate CNT exposures. We conclude that current animal toxicity evidence suggests that strong action needs to be taken to minimize exposures to CNTs, and that any CNT OEL should be consistent with the need to minimize exposures.

  8. Impacts of trace carbon on the microstructure of as-sintered biomedical Ti-15Mo alloy and reassessment of the maximum carbon limit.

    Science.gov (United States)

    Yan, M; Qian, M; Kong, C; Dargusch, M S

    2014-02-01

    The formation of grain boundary (GB) brittle carbides with a complex three-dimensional (3-D) morphology can be detrimental to both the fatigue properties and corrosion resistance of a biomedical titanium alloy. A detailed microscopic study has been performed on an as-sintered biomedical Ti-15Mo (in wt.%) alloy containing 0.032 wt.% C. A noticeable presence of a carbon-enriched phase has been observed along the GB, although the carbon content is well below the maximum carbon limit of 0.1 wt.% specified by ASTM Standard F2066. Transmission electron microscopy (TEM) identified that the carbon-enriched phase is face-centred cubic Ti2C. 3-D tomography reconstruction revealed that the Ti2C structure has morphology similar to primary α-Ti. Nanoindentation confirmed the high hardness and high Young's modulus of the GB Ti2C phase. To avoid GB carbide formation in Ti-15Mo, the carbon content should be limited to 0.006 wt.% by Thermo-Calc predictions. Similar analyses and characterization of the carbide formation in biomedical unalloyed Ti, Ti-6Al-4V and Ti-16Nb have also been performed. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Short-term rhizosphere effect on available carbon sources, phenanthrene degradation and active microbiome in an aged-contaminated industrial soil

    Directory of Open Access Journals (Sweden)

    François eThomas

    2016-02-01

    Full Text Available Over the last decades, understanding of the effects of plants on soil microbiomes has greatly advanced. However, knowledge on the assembly of rhizospheric communities in aged-contaminated industrial soils is still limited, especially with regard to transcriptionally active microbiomes and their link to the quality or quantity of carbon sources. We compared the short-term (2-10 days dynamics of bacterial communities and potential PAH-degrading bacteria in bare or ryegrass-planted aged-contaminated soil spiked with phenanthrene, put in relation with dissolved organic carbon sources and polycyclic aromatic hydrocarbon (PAH pollution. Both resident and active bacterial communities (analyzed from DNA and RNA, respectively showed higher species richness and smaller dispersion between replicates in planted soils. Root development strongly favored the activity of Pseudomonadales within the first two days, and of members of Actinobacteria, Caulobacterales, Rhizobiales and Xanthomonadales within 6-10 days. Plants slowed down the dissipation of phenanthrene, while root exudation provided a cocktail of labile substrates that might preferentially fuel microbial growth. Although the abundance of PAH-degrading genes increased in planted soil, their transcription level stayed similar to bare soil. In addition, network analysis revealed that plants induced an early shift in the identity of potential phenanthrene degraders, which might influence PAH dissipation on the long-term.

  10. Oxygen permeation flux through La1-ySryFeO3 limited by the carbon monoxide oxidation rate

    NARCIS (Netherlands)

    van Hassel, B.A.; van Hassel, B.A.; ten Elshof, Johan E.; Bouwmeester, Henricus J.M.

    1995-01-01

    The oxygen permeation flux through La1-ySryFeO3-δ (y = 0.1, 0.2) in a large oxygen partial pressure gradient (air/CO, CO2 mixture) was found to be limited by the carbon monoxide oxidation rate at the low oxygen partial pressure side of the membrane. The oxygen permeation flux through the membrane

  11. 40 CFR 63.500 - Back-end process provisions-carbon disulfide limitations for styrene butadiene rubber by emulsion...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Back-end process provisions-carbon disulfide limitations for styrene butadiene rubber by emulsion processes. 63.500 Section 63.500 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR...

  12. Progress towards the use of publicly available data networks to conduct cross-scale historical reconstructions of carbon dynamics in US Drylands

    Science.gov (United States)

    Washington-Allen, R. A.; Landolt, K.; Emanuel, R. E.; Therrell, M. D.; Nagle, N.; Grissino-Mayer, H. D.; Poulter, B.

    2016-12-01

    Emergent scale properties of water-limited or Dryland ecosystem's carbon flux are unknown at spatial scales from local to global and time scales of 10 - 1000 years or greater. The width of a tree ring is a metric of production that has been correlated with the amount of precipitation. This relationship has been used to reconstruct rainfall and fire histories in the Drylands of the southwestern US. The normalized difference vegetation index (NDVI) is globally measured by selected satellite sensors and is highly correlated with the fraction of solar radiation which is absorbed for photosynthesis by plants (FPAR), as well as with vegetation biomass, net primary productivity (NPP), and tree ring width. Publicly available web-based archives of free NDVI and tree ring data exist and have allowed historical temporal reconstructions of carbon dynamics for the past 300 to 500 years. Climate and tree ring databases have been used to spatially reconstruct drought dynamics for the last 500 years in the western US. In 2007, we hypothesized that NDVI and tree ring width could be used to spatially reconstruct carbon dynamics in US Drylands. In 2015, we succeeded with a 300-year historical spatial reconstruction of NPP in California using a Blue Oak tree ring chronology. Online eddy covariance flux tower measures of NPP are well correlated with satellite measures of NPP. This suggests that net ecosystem exchange (NEE = NPP - soil Respiration) could be historically reconstructed across Drylands. Ongoing research includes 1) scaling historical spatial reconstruction to US Drylands, 2) comparing the use of single versus multiple tree ring species (r2 = 68) and 3) use of the eddy flux tower network, remote sensing, and tree ring data to historically spatially reconstruct Dryland NEE.

  13. Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

    Science.gov (United States)

    Fabien H. Wagner; Bruno Herault; Damien Bonal; Clement Stahl; Liana O. Anderson; Timothy R. Baker; Gabriel Sebastian Becker; Hans Beeckman; Danilo Boanerges Souza; Paulo Cesar Botosso; David M. J. S. Bowman; Achim Brauning; Benjamin Brede; Foster Irving Brown; Jesus Julio Camarero; Plinio Barbosa Camargo; Fernanda C. G. Cardoso; Fabricio Alvim Carvalho; Wendeson Castro; Rubens Koloski Chagas; Jerome Chave; Emmanuel N. Chidumayo; Deborah A. Clark; Flavia Regina Capellotto Costa; Camille Couralet; Paulo Henrique da Silva Mauricio; Helmut Dalitz; Vinicius Resende de Castro; Jacanan Eloisa de Freitas Milani; Edilson Consuelo de Oliveira; Luciano de Souza Arruda; Jean-Louis Devineau; David M. Drew; Oliver Dunisch; Giselda Durigan; Elisha Elifuraha; Marcio Fedele; Ligia Ferreira Fedele; Afonso Figueiredo Filho; Cesar Augusto Guimaraes Finger; Augusto Cesar Franco; Joao Lima Freitas Junior; Franklin Galvao; Aster Gebrekirstos; Robert Gliniars; Paulo Mauricio Lima de Alencastro Graca; Anthony D. Griffiths; James Grogan; Kaiyu Guan; Jurgen Homeier; Maria Raquel Kanieski; Lip Khoon Kho; Jennifer Koenig; Sintia Valerio Kohler; Julia Krepkowski; Jose Pires Lemos-Filho; Diana Lieberman; Milton Eugene Lieberman; Claudio Sergio Lisi; Tomaz Longhi Santos; Jose Luis Lopez Ayala; Eduardo Eijji Maeda; Yadvinder Malhi; Vivian R. B. Maria; Marcia C. M. Marques; Renato Marques; Hector Maza Chamba; Lawrence Mbwambo; Karina Liana Lisboa Melgaco; Hooz Angela Mendivelso; Brett P. Murphy; Joseph O' Brien; Steven F. Oberbauer; Naoki Okada; Raphael Pelissier; Lynda D. Prior; Fidel Alejandro Roig; Michael Ross; Davi Rodrigo Rossatto; Vivien Rossi; Lucy Rowland; Ervan Rutishauser; Hellen Santana; Mark Schulze; Diogo Selhorst; Williamar Rodrigues Silva; Marcos Silveira; Susanne Spannl; Michael D. Swaine; Jose Julio Toledo; Marcos Miranda Toledo; Marisol Toledo; Takeshi Toma; Mario Tomazello Filho; Juan Ignacio Valdez Hernandez; Jan Verbesselt; Simone Aparecida Vieira; Gregoire Vincent; Carolina Volkmer de Castilho; Franziska Volland; Martin Worbes; Magda Lea Bolzan Zanon; Luiz E. O. C. Aragao

    2016-01-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter...

  14. Limited carbon and biodiversity co-benefits for tropical forest mammals and birds.

    Science.gov (United States)

    Beaudrot, Lydia; Kroetz, Kailin; Alvarez-Loayza, Patricia; Amaral, Eda; Breuer, Thomas; Fletcher, Christine; Jansen, Patrick A; Kenfack, David; Lima, Marcela Guimarães Moreira; Marshall, Andrew R; Martin, Emanuel H; Ndoundou-Hockemba, Mireille; O'Brien, Timothy; Razafimahaimodison, Jean Claude; Romero-Saltos, Hugo; Rovero, Francesco; Roy, Cisquet Hector; Sheil, Douglas; Silva, Carlos E F; Spironello, Wilson Roberto; Valencia, Renato; Zvoleff, Alex; Ahumada, Jorge; Andelman, Sandy

    2016-06-01

    The conservation of tropical forest carbon stocks offers the opportunity to curb climate change by reducing greenhouse gas emissions from deforestation and simultaneously conserve biodiversity. However, there has been considerable debate about the extent to which carbon stock conservation will provide benefits to biodiversity in part because whether forests that contain high carbon density in their aboveground biomass also contain high animal diversity is unknown. Here, we empirically examined medium to large bodied ground-dwelling mammal and bird (hereafter "wildlife") diversity and carbon stock levels within the tropics using camera trap and vegetation data from a pantropical network of sites. Specifically, we tested whether tropical forests that stored more carbon contained higher wildlife species richness, taxonomic diversity, and trait diversity. We found that carbon stocks were not a significant predictor for any of these three measures of diversity, which suggests that benefits for wildlife diversity will not be maximized unless wildlife diversity is explicitly taken into account; prioritizing carbon stocks alone will not necessarily meet biodiversity conservation goals. We recommend conservation planning that considers both objectives because there is the potential for more wildlife diversity and carbon stock conservation to be achieved for the same total budget if both objectives are pursued in tandem rather than independently. Tropical forests with low elevation variability and low tree density supported significantly higher wildlife diversity. These tropical forest characteristics may provide more affordable proxies of wildlife diversity for future multi-objective conservation planning when fine scale data on wildlife are lacking.

  15. Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

    NARCIS (Netherlands)

    Wagner, Fabien H.; Hérault, Bruno; Bonal, Damien; Stahl, Clément; Anderson, Liana O.; Baker, Timothy R.; Becker, Gabriel Sebastian; Beeckman, Hans; Boanerges Souza, Danilo; Botosso, Paulo Cesar; Bowman, David M.J.S.; Bräuning, Achim; Brede, Benjamin; Brown, Foster Irving; Camarero, Jesus Julio; Camargo, Plínio Barbosa; Cardoso, Fernanda C.G.; Carvalho, Fabrício Alvim; Castro, Wendeson; Chagas, Rubens Koloski; Chave, Jérome; Chidumayo, Emmanuel N.; Clark, Deborah A.; Costa, Flavia Regina Capellotto; Couralet, Camille; Silva Mauricio, Da Paulo Henrique; Dalitz, Helmut; Castro, De Vinicius Resende; Freitas Milani, De Jaçanan Eloisa; Oliveira, De Edilson Consuelo; Souza Arruda, De Luciano; Devineau, Jean-Louis; Drew, David M.; Dünisch, Oliver; Durigan, Giselda; Elifuraha, Elisha; Fedele, Marcio; Ferreira Fedele, Ligia; Figueiredo Filho, Afonso; Finger, César Augusto Guimarães; Franco, Augusto César; Freitas Júnior, João Lima; Galvão, Franklin; Gebrekirstos, Aster; Gliniars, Robert; Lima De Alencastro Graça, Paulo Maurício; Griffiths, Anthony D.; Grogan, James; Guan, Kaiyu; Homeier, Jürgen; Kanieski, Maria Raquel; Kho, Lip Khoon; Koenig, Jennifer; Kohler, Sintia Valerio; Krepkowski, Julia; Lemos-filho, José Pires; Lieberman, Diana; Lieberman, Milton Eugene; Lisi, Claudio Sergio; Longhi Santos, Tomaz; López Ayala, José Luis; Maeda, Eduardo Eijji; Malhi, Yadvinder; Maria, Vivian R.B.; Marques, Marcia C.M.; Marques, Renato; Maza Chamba, Hector; Mbwambo, Lawrence; Melgaço, Karina Liana Lisboa; Mendivelso, Hooz Angela; Murphy, Brett P.; O'Brien, Joseph J.; Oberbauer, Steven F.; Okada, Naoki; Pélissier, Raphaël; Prior, Lynda D.; Roig, Fidel Alejandro; Ross, Michael; Rossatto, Davi Rodrigo; Rossi, Vivien; Rowland, Lucy; Rutishauser, Ervan; Santana, Hellen; Schulze, Mark; Selhorst, Diogo; Silva, Williamar Rodrigues; Silveira, Marcos; Spannl, Susanne; Swaine, Michael D.; Toledo, José Julio; Toledo, Marcos Miranda; Toledo, Marisol; Toma, Takeshi; Tomazello Filho, Mario; Valdez Hernández, Juan Ignacio; Verbesselt, Jan; Vieira, Simone Aparecida; Vincent, Grégoire; Volkmer De Castilho, Carolina; Volland, Franziska; Worbes, Martin; Zanon, Magda Lea Bolzan; Aragão, Luiz E.O.C.

    2016-01-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68

  16. Carbon translocation from symbiont to host depends on irradiance and food availability in the tropical coral Stylophora pistillata

    Science.gov (United States)

    Tremblay, P.; Grover, R.; Maguer, J. F.; Hoogenboom, M.; Ferrier-Pagès, C.

    2014-03-01

    Reef-building corals live in symbiosis with dinoflagellates that translocate a large proportion of their photosynthetically fixed carbon compounds to their coral host for its own metabolism. The carbon budget and translocation rate, however, vary depending on environmental conditions, coral host species, and symbiont clade. To quantify variability in carbon translocation in response to environmental conditions, this study assessed the effect of two different irradiance levels (120 and 250 μmol photons m-2 s-1) and feeding regimes (fed with Artemia salina nauplii and unfed) on the carbon budget of the tropical coral Stylophora pistillata. For this purpose, H13CO3 --enriched seawater was used to trace the conversion of photosynthetic carbon into symbiont and coral biomass and excrete particulate organic carbon. Results showed that carbon translocation (ca. 78 %) and utilization were similar under both irradiance levels for unfed colonies. In contrast, carbon utilization by fed colonies was dependent on the growth irradiance. Under low irradiance, heterotrophy was accompanied by lower carbon translocation (71 %), higher host and symbiont biomass, and higher calcification rates. Under high irradiance, heterotrophy was accompanied by higher rates of photosynthesis, respiration, and carbon translocation (90 %) as well as higher host biomass. Hence, levels of resource sharing within coral-dinoflagellate symbioses depend critically on environmental conditions.

  17. Nitrogen, organic carbon and sulphur cycling in terrestrial ecosystems: linking nitrogen saturation to carbon limitation of soil microbial processes

    Czech Academy of Sciences Publication Activity Database

    Kopáček, Jiří; Cosby, B. J.; Evans, C. D.; Hruška, J.; Moldan, F.; Oulehle, F.; Šantrůčková, H.; Tahovská, K.; Wright, R. F.

    2013-01-01

    Roč. 115, 1-3 (2013), s. 33-51 ISSN 0168-2563. [BIOGEOMON : international symposium on ecosystem behavior /7./. Northport, 15.07.2012-20.07.2012] R&D Projects: GA ČR(CZ) GAP504/12/1218 Institutional support: RVO:60077344 Keywords : nitrogen * carbon * sulphur * acidification * forest soil * modelling Subject RIV: DJ - Water Pollution ; Quality Impact factor: 3.730, year: 2013

  18. TU-G-BRCD-01: Will the High Cost of Proton Therapy Facilities Limit the Availability of Proton Therapy Treatment?

    Science.gov (United States)

    Maughan, R

    2012-06-01

    The potential dose distribution advantages associated with proton therapy, and particularly with pencil beam scanning (PBS) techniques, have lead to considerable interest in this modality in recent years. However, the large capital expenditure necessary for such a project requires careful financial consideration and business planning. The complexity of the beam delivery systems impacts the capital expenditure and the PBS only systems presently being advocated can reduce these costs. Also several manufacturers are considering "one-room" facilities as less expensive alternatives to multi-room facilities. This presentation includes a brief introduction to beam delivery options (passive scattering, uniform and modulated scanning) and some of the new technologies proposed for providing less expensive proton therapy systems. Based on current experience, data on proton therapy center start-up costs, running costs and the financial challenges associated with making this highly conformal therapy more widely available will be discussed. Issues associated with proton therapy implementation that are key to project success include strong project management, vendor cooperation and collaboration, staff recruitment and training. Time management during facility start up is a major concern, particularly in multi-room systems, where time must be shared between continuing vendor system validation, verification and acceptance testing, and user commissioning and patient treatments. The challenges associated with facility operation during this period and beyond are discussed, focusing on how standardization of process, downtime and smart scheduling can influence operational efficiency. 1. To understand the available choices for proton therapy facilities, the different beam delivery systems and the financial implications associated with these choices. 2. To understand the key elements necessary for successfully implementing a proton therapy program. 3. To understand the challenges

  19. Particle flux and temperature dependence of carbon impurity production from an inertially-cooled limiter in tore supra

    International Nuclear Information System (INIS)

    DeMichelis, C.; Monier-Garbet, P.; Guilhem, D.

    1998-01-01

    A visible endoscope system and an infrared camera system have been used to study the flux of carbon from an inertially-cooled graphite limiter in Tore Supra. From the variation in the carbon flux with plasma parameters new data have been obtained describing the dependence of radiation enhanced sublimation (RES) and chemical sputtering on incident ion flux. Other characteristics of RES under plasma operation conditions have also been studied. The dependence of RES on incident deuterium particle flux density is found to be in reasonable agreement with the expected particle flux scaling over a range of particle fluxes varying by a factor ∼ 25, extending the present scaling to higher flux density values. Chemical sputtering has been observed, but only in regions of the limiter with low incident deuterium fluxes. Values inferred for the chemical sputtering yield are similar to those measured with a temperature controlled test limiter in Textor. (author)

  20. Dynamical instability of the envelope of red supergiants and the lower mass limit for carbon detonation supernovae

    International Nuclear Information System (INIS)

    Fujimoto, M.Y.; Nomoto, K.; Sugimoto, D.

    1976-01-01

    The lower mass limit Msub(l) for the carbon detonation supernovae was investigated by testing the dynamical instability of the envelopes of red supergiants. It was found that the dependence of Msub(l) on the mixing length l of convection is appreciable. As a smaller value of l is assumed, Msub(l) becomes larger. It may be as large as 8 solar masses if l is a third of the pressure scale-height. This is one of the ways to remove the difficulty of overproduction of iron-peak elements involved in the model of the carbon detonation supernovae. (Auth.)

  1. Dynamical instability of the envelope of red supergiants and the lower mass limit for carbon detonation supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, M Y [Tokyo Univ. (Japan); Nomoto, K; Sugimoto, D [Tokyo Univ. (Japan). Coll. of General Education

    1976-11-01

    The lower mass limit Msub(l) for the carbon detonation supernovae was investigated by testing the dynamical instability of the envelopes of red supergiants. It was found that the dependence of Msub(l) on the mixing length l of convection is appreciable. As a smaller value of l is assumed, Msub(l) becomes larger. It may be as large as 8 solar masses if l is a third of the pressure scale-height. This is one of the ways to remove the difficulty of overproduction of iron-peak elements involved in the model of the carbon detonation supernovae.

  2. Evidence of different stoichiometries for the limiting carbonate complexes of lanthanides(3); Mise en evidence d'un changement de stoechiometrie du complexe carbonate limite au sein de la serie des lanthanides(3)

    Energy Technology Data Exchange (ETDEWEB)

    Philippini, V

    2007-12-15

    Two stoichiometries have been proposed by different laboratories to interpret measurements on the limiting carbonate complexes of An{sup 3+} and Ln{sup 3+} cations. The study of the solubility of double carbonates (AlkLn(CO{sub 3}){sub 2},xH{sub 2}O) in concentrated carbonate solutions at room temperature and high ionic strengths has shown that on the one hand the lightest lanthanides (La and Nd) form Ln(CO{sub 3}){sub 4}{sup 5-} whereas the heaviest (Eu and Dy) form Ln(CO{sub 3}){sub 3}{sup 3-} in the studied chemical conditions, and on the other hand, that the kinetics of precipitation of double carbonates depends on the alkali metal and the lanthanide ions. The existence of two stoichiometries for the limiting carbonate complexes was confirmed by capillary electrophoresis hyphenated to an inductively coupled plasma mass spectrometer (CE-ICP-MS), used to extend the study to the whole series of lanthanides (except Ce, Pm and Yb). Two behaviours have been put forward comparing the electrophoretic mobilities: La to Tb form Ln(CO{sub 3}){sub 4}{sup 5-} while Dy to Lu form Ln(CO{sub 3}){sub 3}{sup 3-}. Measurements by time resolved laser fluorescence spectroscopy (TRLFS) on Eu(III) indicate small variations of the geometry of Eu(CO{sub 3}){sub 3}{sup 3-} complex, specially with Cs{sup +}. Although analogies are currently used among the 4f-block trivalent elements, different aqueous speciations are evidenced in concentrated carbonate solutions across the lanthanide series. (author)

  3. Carbon utilization by fruit limits shoot growth in alternate-bearing citrus trees.

    Science.gov (United States)

    Martínez-Alcántara, Belén; Iglesias, Domingo J; Reig, Carmina; Mesejo, Carlos; Agustí, Manuel; Primo-Millo, Eduardo

    2015-03-15

    Fruit load in alternate-bearing citrus trees is reported to alter shoot number and growth during spring, summer, and autumn flushes, and the source-sink balance, which affects the storage and mobilization of reserve nutrients. The aim of this work was to assess the extent of shoot growth inhibition resulting from the presence of fruits in 'Moncada' mandarin trees loaded with fruit (ON) or with very light fruit load (OFF), and to identify the role of carbohydrates and nitrogenous compounds in the competition between fruits and shoots. Growth of reproductive and vegetative organs was measured on a monthly basis. (13)C- and (15)N-labeled compounds were supplied to trace the allocation of reserve nutrients and subsequent translocation from source to sink. At the end of the year, OFF trees produced more abundant flushes (2.4- and 4.9-fold higher in number and biomass, respectively) than ON trees. Fruits from ON trees accumulated higher C amounts at the expense of developing flushes, whereas OFF trees exhibited the opposite pattern. An inverse relationship was identified between the amount of C utilized by fruits and vegetative flush growth. (13)C-labeling revealed an important role for mature leaves of fruit-bearing branches in supporting shoot/fruit growth, and the elevated sink strength of growing fruits on shoots. N availability for vegetative shoots was not affected by the presence or absence of fruits, which accumulated important amounts of (15)N. In conclusion, our results show that shoot growth is resource-limited as a consequence of fruit development, and vegetative-growth inhibition is caused by photoassimilate limitation. The competence for N is not a decisive factor in limiting vegetative growth under the experimental conditions of this study. Copyright © 2014 Elsevier GmbH. All rights reserved.

  4. Circumpolar assessment of rhizosphere priming shows limited increase in carbon loss estimates for permafrost soils but large regional variability

    Science.gov (United States)

    Wild, B.; Keuper, F.; Kummu, M.; Beer, C.; Blume-Werry, G.; Fontaine, S.; Gavazov, K.; Gentsch, N.; Guggenberger, G.; Hugelius, G.; Jalava, M.; Koven, C.; Krab, E. J.; Kuhry, P.; Monteux, S.; Richter, A.; Shazhad, T.; Dorrepaal, E.

    2017-12-01

    Predictions of soil organic carbon (SOC) losses in the northern circumpolar permafrost area converge around 15% (± 3% standard error) of the initial C pool by 2100 under the RCP 8.5 warming scenario. Yet, none of these estimates consider plant-soil interactions such as the rhizosphere priming effect (RPE). While laboratory experiments have shown that the input of plant-derived compounds can stimulate SOC losses by up to 1200%, the magnitude of RPE in natural ecosystems is unknown and no methods for upscaling exist so far. We here present the first spatial and depth explicit RPE model that allows estimates of RPE on a large scale (PrimeSCale). We combine available spatial data (SOC, C/N, GPP, ALT and ecosystem type) and new ecological insights to assess the importance of the RPE at the circumpolar scale. We use a positive saturating relationship between the RPE and belowground C allocation and two ALT-dependent rooting-depth distribution functions (for tundra and boreal forest) to proportionally assign belowground C allocation and RPE to individual soil depth increments. The model permits to take into account reasonable limiting factors on additional SOC losses by RPE including interactions between spatial and/or depth variation in GPP, plant root density, SOC stocks and ALT. We estimate potential RPE-induced SOC losses at 9.7 Pg C (5 - 95% CI: 1.5 - 23.2 Pg C) by 2100 (RCP 8.5). This corresponds to an increase of the current permafrost SOC-loss estimate from 15% of the initial C pool to about 16%. If we apply an additional molar C/N threshold of 20 to account for microbial C limitation as a requirement for the RPE, SOC losses by RPE are further reduced to 6.5 Pg C (5 - 95% CI: 1.0 - 16.8 Pg C) by 2100 (RCP 8.5). Although our results show that current estimates of permafrost soil C losses are robust without taking into account the RPE, our model also highlights high-RPE risk in Siberian lowland areas and Alaska north of the Brooks Range. The small overall impact of

  5. vSDC: a method to improve early recognition in virtual screening when limited experimental resources are available.

    Science.gov (United States)

    Chaput, Ludovic; Martinez-Sanz, Juan; Quiniou, Eric; Rigolet, Pascal; Saettel, Nicolas; Mouawad, Liliane

    2016-01-01

    In drug design, one may be confronted to the problem of finding hits for targets for which no small inhibiting molecules are known and only low-throughput experiments are available (like ITC or NMR studies), two common difficulties encountered in a typical academic setting. Using a virtual screening strategy like docking can alleviate some of the problems and save a considerable amount of time by selecting only top-ranking molecules, but only if the method is very efficient, i.e. when a good proportion of actives are found in the 1-10 % best ranked molecules. The use of several programs (in our study, Gold, Surflex, FlexX and Glide were considered) shows a divergence of the results, which presents a difficulty in guiding the experiments. To overcome this divergence and increase the yield of the virtual screening, we created the standard deviation consensus (SDC) and variable SDC (vSDC) methods, consisting of the intersection of molecule sets from several virtual screening programs, based on the standard deviations of their ranking distributions. SDC allowed us to find hits for two new protein targets by testing only 9 and 11 small molecules from a chemical library of circa 15,000 compounds. Furthermore, vSDC, when applied to the 102 proteins of the DUD-E benchmarking database, succeeded in finding more hits than any of the four isolated programs for 13-60 % of the targets. In addition, when only 10 molecules of each of the 102 chemical libraries were considered, vSDC performed better in the number of hits found, with an improvement of 6-24 % over the 10 best-ranked molecules given by the individual docking programs.Graphical abstractIn drug design, for a given target and a given chemical library, the results obtained with different virtual screening programs are divergent. So how to rationally guide the experimental tests, especially when only a few number of experiments can be made? The variable Standard Deviation Consensus (vSDC) method was developed to

  6. Steady-State Growth under Inorganic Carbon Limitation Conditions Increases Energy Consumption for Maintenance and Enhances Nitrous Oxide Production in Nitrosomonas europaea.

    Science.gov (United States)

    Mellbye, Brett L; Giguere, Andrew; Chaplen, Frank; Bottomley, Peter J; Sayavedra-Soto, Luis A

    2016-06-01

    Nitrosomonas europaea is a chemolithoautotrophic bacterium that oxidizes ammonia (NH3) to obtain energy for growth on carbon dioxide (CO2) and can also produce nitrous oxide (N2O), a greenhouse gas. We interrogated the growth, physiological, and transcriptome responses of N. europaea to conditions of replete (>5.2 mM) and limited inorganic carbon (IC) provided by either 1.0 mM or 0.2 mM sodium carbonate (Na2CO3) supplemented with atmospheric CO2 IC-limited cultures oxidized 25 to 58% of available NH3 to nitrite, depending on the dilution rate and Na2CO3 concentration. IC limitation resulted in a 2.3-fold increase in cellular maintenance energy requirements compared to those for NH3-limited cultures. Rates of N2O production increased 2.5- and 6.3-fold under the two IC-limited conditions, increasing the percentage of oxidized NH3-N that was transformed to N2O-N from 0.5% (replete) up to 4.4% (0.2 mM Na2CO3). Transcriptome analysis showed differential expression (P ≤ 0.05) of 488 genes (20% of inventory) between replete and IC-limited conditions, but few differences were detected between the two IC-limiting treatments. IC-limited conditions resulted in a decreased expression of ammonium/ammonia transporter and ammonia monooxygenase subunits and increased the expression of genes involved in C1 metabolism, including the genes for RuBisCO (cbb gene cluster), carbonic anhydrase, folate-linked metabolism of C1 moieties, and putative C salvage due to oxygenase activity of RuBisCO. Increased expression of nitrite reductase (gene cluster NE0924 to NE0927) correlated with increased production of N2O. Together, these data suggest that N. europaea adapts physiologically during IC-limited steady-state growth, which leads to the uncoupling of NH3 oxidation from growth and increased N2O production. Nitrification, the aerobic oxidation of ammonia to nitrate via nitrite, is an important process in the global nitrogen cycle. This process is generally dependent on ammonia

  7. The limits to global-warming mitigation by terrestrial carbon removal

    OpenAIRE

    Boysen, L.; Lucht, W.; Gerten, D.; Heck, V.; Lenton, T.; Schellnhuber, H.

    2017-01-01

    Massive near-term greenhouse gas emissions reduction is a precondition for staying "well below 2°C" global warming as envisaged by the Paris Agreement. Furthermore, extensive terrestrial carbon dioxide removal (tCDR) through managed biomass growth and subsequent carbon capture and storage is required to avoid temperature "overshoot" in most pertinent scenarios. Here, we address two major issues: First, we calculate the extent of tCDR required to "repair" delayed or insufficient emissions redu...

  8. Limitations of disordered carbons obtained from biomass as anodes for real lithium-ion batteries.

    Science.gov (United States)

    Caballero, Alvaro; Hernán, Lourdes; Morales, Julián

    2011-05-23

    Two disordered microporous carbons were obtained from two different types of biomass residues: olive and cherry stones. The former (OS) was activated physically under steam while the latter (CS) chemically with an aqueous solution of ZnCl(2). Their structural and textural properties were studied by X-ray diffraction, scanning electron microscopy, and N(2) adsorption/desorption. Although the samples possess similar textural properties (BET surface areas, micropore surfaces and volumes), the CS carbon is more disordered than the OS carbon. Their electrochemical response in half-cells (CS[OS]/Li) is good; the values are comparable to those obtained from mesocarbon microbeads commonly used in commercial lithium-ion batteries, which consist of highly graphitized carbon. However, cells featuring the OS or CS carbon as anode and LiMn(2)O(4) as cathode perform poorly. Electrochemical activation of the electrodes against lithium metal, a recommended procedure for boosting the electrochemical properties of real lithium-ion batteries, improves cell performance (particularly with OS) but is ultimately ineffective: the delivered average capacity of the activated cell made from OS was less than half its theoretical value. The high irreversible capacity, high polarization between the charge and discharge curves, combined with the presence of various functional groups and the high disorder of the studied carbons which may facilitate side reactions such as electrolyte decomposition, results in a degraded cell performance. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effect of light and nutrient availability on the release of dissolved organic carbon (DOC) by Caribbean turf algae

    NARCIS (Netherlands)

    Mueller, B.; den Haan, J.; Visser, P.M.; Vermeij, M.J.A.; van Duyl, F.C.

    2016-01-01

    Turf algae increasingly dominate benthic communities on coral reefs. Given their abundance and high dissolved organic carbon (DOC) release rates, turf algae are considered important contributors to the DOC pool on modern reefs. The release of photosynthetically fixed carbon as DOC generally, but not

  10. Carbon Inputs From Riparian Vegetation Limit Oxidation of Physically Bound Organic Carbon Via Biochemical and Thermodynamic Processes

    Science.gov (United States)

    Graham, Emily B.; Tfaily, Malak M.; Crump, Alex R.; Goldman, Amy E.; Bramer, Lisa M.; Arntzen, Evan; Romero, Elvira; Resch, C. Tom; Kennedy, David W.; Stegen, James C.

    2017-12-01

    In light of increasing terrestrial carbon (C) transport across aquatic boundaries, the mechanisms governing organic carbon (OC) oxidation along terrestrial-aquatic interfaces are crucial to future climate predictions. Here we investigate the biochemistry, metabolic pathways, and thermodynamics corresponding to OC oxidation in the Columbia River corridor using ultrahigh-resolution C characterization. We leverage natural vegetative differences to encompass variation in terrestrial C inputs. Our results suggest that decreases in terrestrial C deposition associated with diminished riparian vegetation induce oxidation of physically bound OC. We also find that contrasting metabolic pathways oxidize OC in the presence and absence of vegetation and—in direct conflict with the "priming" concept—that inputs of water-soluble and thermodynamically favorable terrestrial OC protect bound-OC from oxidation. In both environments, the most thermodynamically favorable compounds appear to be preferentially oxidized regardless of which OC pool microbiomes metabolize. In turn, we suggest that the extent of riparian vegetation causes sediment microbiomes to locally adapt to oxidize a particular pool of OC but that common thermodynamic principles govern the oxidation of each pool (i.e., water-soluble or physically bound). Finally, we propose a mechanistic conceptualization of OC oxidation along terrestrial-aquatic interfaces that can be used to model heterogeneous patterns of OC loss under changing land cover distributions.

  11. Organic carbon and nitrogen availability determine bacterial community composition in paddy fields of the Indo-Gangetic plain.

    Science.gov (United States)

    Kumar, Arvind; Rai, Lal Chand

    2017-07-01

    Soil quality is an important factor and maintained by inhabited microorganisms. Soil physicochemical characteristics determine indigenous microbial population and rice provides food security to major population of the world. Therefore, this study aimed to assess the impact of physicochemical variables on bacterial community composition and diversity in conventional paddy fields which could reflect a real picture of the bacterial communities operating in the paddy agro-ecosystem. To fulfill the objective; soil physicochemical characterization, bacterial community composition and diversity analysis was carried out using culture-independent PCR-DGGE method from twenty soils distributed across eight districts. Bacterial communities were grouped into three clusters based on UPGMA cluster analysis of DGGE banding pattern. The linkage of measured physicochemical variables with bacterial community composition was analyzed by canonical correspondence analysis (CCA). CCA ordination biplot results were similar to UPGMA cluster analysis. High levels of species-environment correlations (0.989 and 0.959) were observed and the largest proportion of species data variability was explained by total organic carbon (TOC), available nitrogen, total nitrogen and pH. Thus, results suggest that TOC and nitrogen are key regulators of bacterial community composition in the conventional paddy fields. Further, high diversity indices and evenness values demonstrated heterogeneity and co-abundance of the bacterial communities.

  12. 75 FR 77828 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil: Extension of Time Limit...

    Science.gov (United States)

    2010-12-14

    ...-Rolled Carbon-Quality Steel Products From Brazil: Extension of Time Limit for Final Results of...-Rolled Carbon Quality Steel Products From Brazil: Preliminary Results of Countervailing Duty... administrative review of the countervailing duty order on certain hot-rolled flat-rolled carbon- quality steel...

  13. Iceberg killing fields limit huge potential for benthic blue carbon in Antarctic shallows.

    Science.gov (United States)

    Barnes, David K A

    2017-07-01

    Climate-forced ice losses are increasing potential for iceberg-seabed collisions, termed ice scour. At Ryder Bay, West Antarctic Peninsula (WAP) sea ice, oceanography, phytoplankton and encrusting zoobenthos have been monitored since 1998. In 2003, grids of seabed markers, covering 225 m 2 , were established, surveyed and replaced annually to measure ice scour frequency. Disturbance history has been recorded for each m 2 of seabed monitored at 5-25 m for ~13 years. Encrusting fauna, collected from impacted and nonimpacted metres each year, show coincident benthos responses in growth, mortality and mass of benthic immobilized carbon. Encrusting benthic growth was mainly determined by microalgal bloom duration; each day, nanophytoplankton exceeded 200 μg L -1 produced ~0.05 mm radial growth of bryozoans, and sea temperature >0 °C added 0.002 mm day -1 . Mortality and persistence of growth, as benthic carbon immobilization, were mainly influenced by ice scour. Nearly 30% of monitored seabed was hit each year, and just 7% of shallows were not hit. Hits in deeper water were more deadly, but less frequent, so mortality decreased with depth. Five-year recovery time doubled benthic carbon stocks. Scour-driven mortality varied annually, with two-thirds of all monitored fauna killed in a single year (2009). Reduced fast ice after 2006 ramped iceberg scouring, killing half the encrusting benthos each year in following years. Ice scour coupled with low phytoplankton biomass drove a phase shift to high mortality and depressed zoobenthic immobilized carbon stocks, which has persevered for 10 years since. Stocks of immobilized benthic carbon averaged nearly 15 g m -2 . WAP ice scouring may be recycling 80 000 tonnes of carbon yr -1 . Without scouring, such carbon would remain immobilized and the 2.3% of shelf which are shallows could be as productive as all the remaining continental shelf. The region's future, when glaciers reach grounding lines and iceberg

  14. Effect of nutrient availability on carbon and nitrogen incorporation and flows through benthic algae and bacteria in near-shore sandy sediment

    NARCIS (Netherlands)

    Cook, P.; Veuger, B.; Böer, S.; Middelburg, J.J.

    2007-01-01

    Carbon and nitrogen uptake in a microbial community comprising bacteria and microalgae in a sandy marine sediment under nutrient-limited and -replete conditions was studied using a mesocosm approach. After 2 wk of incubation, a pulse of H13CO3– and 15NH4+ was added to the mesocosms, and subsequent

  15. Spectrophotometric Analysis of the Kinetic of Pd(II Chloride Complex Ions Sorption Process from Diluted Aqua Solutions Using Commercially Available Activated Carbon

    Directory of Open Access Journals (Sweden)

    Wojnicki M.

    2017-12-01

    Full Text Available In this paper, results of adsorption kinetic studies of Pd(II chloride complex ions on activated carbon Organosrob 10 CO are presented. Spectorphotometrical method was applied to investigate the process. Kinetic model was proposed, and fundamental thermodynamic parameters were determined. Proposed kinetic model describes well observed phenomenon in the studied range of concentration of Pd(II chloride complex ions as well, as concentration of activated carbon.

  16. Impacts of carbon pricing, brown coal availability and gas cost on Czech energy system up to 2050

    International Nuclear Information System (INIS)

    Rečka, L.; Ščasný, M.

    2016-01-01

    A dynamic partial equilibrium model, TIMES (​The Integrated MARKAL-EFOM System), is built to optimize the energy system in a post-transition European country, the Czech Republic. The impacts of overall nine scenarios on installed capacity, capital and fuel costs, air quality pollutant emission, emission of CO_2 and environmental and health damage are quantified for a period up to 2050. These scenarios are built around three different price sets of the EUA (EU allowance) to emit greenhouse gasses alongside a policy that retains the ban on brown coal mining in two Czech mines, a policy that will allow the re-opening of mining areas under this ban (i.e. within the territorial ecological limits), and a low natural gas price assumption. We found that the use of up until now dominant brown coal will be significantly reduced in each scenario, although reopening the coal mines will result in its smaller decline. With low EUA price, hard coal will become the dominant fuel in electricity generation, while nuclear will overtake this position with a 51% or even 65% share assuming the central price of EUA, or high EUA price, respectively. The low price of natural gas will result in an increasing gas share from an almost zero share recently up to about 42%. This stimulus does not however appear at all with low EUA price. Neither of these scenarios will achieve the renewable energy sources 2030 targets and only a high EUA price will lead to almost full de-carbonization of the Czech power system, with fossil fuels representing only 16% of the energy mix. The low EUA price will result in an increase in CO_2 emissions, whereas the high EUA price will reduce CO_2 emission by at least 81% compared to the 2015 reference level. Those scenarios that will result in CO_2 emission reduction will also generate ancillary benefits due to reduction in air quality emissions, on average over the entire period, at least at 38€ per t of avoided CO_2, whereas scenarios that will lead to CO_2

  17. Incorporating seeds in activated carbon pellets limits herbicide effects to seeded bunchgrasses when controlling exotic annuals

    Science.gov (United States)

    Revegetation of exotic annual grass-invaded rangeland with pre-emergent herbicides is challenging because seeding is delayed until herbicide toxicity has diminished, but at this time, exotic annuals can be re-invading. Incorporating seeds into activated carbon pellets may allow seeding to occur at t...

  18. Reduced substrate supply limits the temperature response of soil organic carbon decomposition

    Science.gov (United States)

    Cinzia Fissore; Christian P. Giardina; Randall K. Kolka

    2013-01-01

    Controls on the decomposition rate of soil organic carbon (SOC), especially the more stable fraction of SOC, remain poorly understood, with implications for confidence in efforts to model terrestrial C balance under future climate. We investigated the role of substrate supply in the temperature sensitivity of SOC decomposition in laboratory incubations of coarse-...

  19. Carbon Sequestration in loblolly pine plantations: Methods, limitations, and research needs for estimating storage pools

    Science.gov (United States)

    Kurt Johnsen; Bob Teskey; Lisa Samuelson; John Butnor; David Sampson; Felipe Sanchez; Chris Maier; Steve McKeand

    2004-01-01

    Globally, the species most widely used for plantation forestry is loblolly pine (Pinus taeda L.). Because loblolly pine plantations are so extensive and grow so rapidly, they provide a great potential for sequestering atmospheric carbon (C). Because loblolly pine plantations are relatively simple ecosystems and because such a great volume of...

  20. Selectivity and limitations of carbon sorption tubes for capturing siloxanes in biogas during field sampling.

    Science.gov (United States)

    Tansel, Berrin; Surita, Sharon C

    2016-06-01

    Siloxane levels in biogas can jeopardize the warranties of the engines used at the biogas to energy facilities. The chemical structure of siloxanes consists of silicon and oxygen atoms, alternating in position, with hydrocarbon groups attached to the silicon side chain. Siloxanes can be either in cyclic (D) or linear (L) configuration and referred with a letter corresponding to their structure followed by a number corresponding to the number of silicon atoms present. When siloxanes are burned, the hydrocarbon fraction is lost and silicon is converted to silicates. The purpose of this study was to evaluate the adequacy of activated carbon gas samplers for quantitative analysis of siloxanes in biogas samples. Biogas samples were collected from a landfill and an anaerobic digester using multiple carbon sorbent tubes assembled in series. One set of samples was collected for 30min (sampling 6-L gas), and the second set was collected for 60min (sampling 12-L gas). Carbon particles were thermally desorbed and analyzed by Gas Chromatography Mass Spectrometry (GC/MS). The results showed that biogas sampling using a single tube would not adequately capture octamethyltrisiloxane (L3), hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6). Even with 4 tubes were used in series, D5 was not captured effectively. The single sorbent tube sampling method was adequate only for capturing trimethylsilanol (TMS) and hexamethyldisiloxane (L2). Affinity of siloxanes for activated carbon decreased with increasing molecular weight. Using multiple carbon sorbent tubes in series can be an appropriate method for developing a standard procedure for determining siloxane levels for low molecular weight siloxanes (up to D3). Appropriate quality assurance and quality control procedures should be developed for adequately quantifying the levels of the higher molecular weight siloxanes in biogas with sorbent tubes

  1. Incentives for small clubs of Arctic countries to limit black carbon and methane emissions

    Science.gov (United States)

    Aakre, Stine; Kallbekken, Steffen; Van Dingenen, Rita; Victor, David G.

    2018-01-01

    Although addressing climate change will ultimately require global cooperation, substantial progress may be achieved through small clubs of countries, where it is easier to forge and implement deals needed for policy coordination. Here we quantify the gains from cooperation in the Arctic region and find that nearly 90% of the potential for abating black carbon can be reached by countries acting in self-interest alone because soot, the main source of black carbon, causes severe harm to human health along with warming. Abating methane, by contrast, requires more cooperation because impacts are more diffused geographically. Well-designed clubs with as few as four members can realize more than 80% of the full group cooperation potential for reducing these pollutants. The pivotal player in every effective club is Russia—most other members of the Arctic Council, the institution most focused on advancing the collective interests of the region, offer little leverage on the problems at hand.

  2. Phase diagram of carbon and the factors limiting the quantity and size of natural diamonds

    Science.gov (United States)

    Blank, Vladimir D.; Churkin, Valentin D.; Kulnitskiy, Boris A.; Perezhogin, Igor A.; Kirichenko, Alexey N.; Denisov, Viktor N.; Erohin, Sergey V.; Sorokin, Pavel B.; Popov, Mikhail Yu

    2018-03-01

    Phase diagrams of carbon, and those focusing on the graphite-to-diamond transitional conditions in particular, are of great interest for fundamental and applied research. The present study introduces a number of experiments carried out to convert graphite under high-pressure conditions, showing a formation of stable phase of fullerene-type onions cross-linked by sp3-bonds in the 55-115 GPa pressure range instead of diamonds formation (even at temperature 2000-3000 K) and the already formed diamonds turn into carbon onions. Our results refute the widespread idea that diamonds can form at any pressure from 2.2 to 1000 GPa. The phase diagram built within this study allows us not only to explain the existing numerous experimental data on the formation of diamond from graphite, but also to make assumptions about the conditions of its growth in Earth’s crust.

  3. Life Prediction on a T700 Carbon Fiber Reinforced Cylinder with Limited Accelerated Life Testing Data

    OpenAIRE

    Ma Xiaobing; Zhang Yongbo

    2015-01-01

    An accelerated life testing investigation was conducted on a composite cylinder that consists of aluminum alloy and T700 carbon fiber. The ultimate failure stress predictions of cylinders were obtained by the mixing rule and verified by the blasting static pressure method. Based on the stress prediction of cylinder under working conditions, the constant stress accelerated life test of the cylinder was designed. However, the failure data cannot be sufficiently obtained by the accelerated life ...

  4. Reviews and syntheses: An empirical spatiotemporal description of the global surface–atmosphere carbon fluxes: opportunities and data limitations

    Directory of Open Access Journals (Sweden)

    J. Zscheischler

    2017-08-01

    Full Text Available Understanding the global carbon (C cycle is of crucial importance to map current and future climate dynamics relative to global environmental change. A full characterization of C cycling requires detailed information on spatiotemporal patterns of surface–atmosphere fluxes. However, relevant C cycle observations are highly variable in their coverage and reporting standards. Especially problematic is the lack of integration of the carbon dioxide (CO2 exchange of the ocean, inland freshwaters and the land surface with the atmosphere. Here we adopt a data-driven approach to synthesize a wide range of observation-based spatially explicit surface–atmosphere CO2 fluxes from 2001 to 2010, to identify the state of today's observational opportunities and data limitations. The considered fluxes include net exchange of open oceans, continental shelves, estuaries, rivers, and lakes, as well as CO2 fluxes related to net ecosystem productivity, fire emissions, loss of tropical aboveground C, harvested wood and crops, as well as fossil fuel and cement emissions. Spatially explicit CO2 fluxes are obtained through geostatistical and/or remote-sensing-based upscaling, thereby minimizing biophysical or biogeochemical assumptions encoded in process-based models. We estimate a bottom-up net C exchange (NCE between the surface (land, ocean, and coastal areas and the atmosphere. Though we provide also global estimates, the primary goal of this study is to identify key uncertainties and observational shortcomings that need to be prioritized in the expansion of in situ observatories. Uncertainties for NCE and its components are derived using resampling. In many regions, our NCE estimates agree well with independent estimates from other sources such as process-based models and atmospheric inversions. This holds for Europe (mean ± 1 SD: 0.8 ± 0.1 PgC yr−1, positive numbers are sources to the atmosphere, Russia (0.1 ± 0.4 PgC yr−1, East Asia

  5. Spatial variability of soil carbon, pH, available phosphorous and potassium in organic farm located in Mediterranean Croatia

    Science.gov (United States)

    Bogunović, Igor; Pereira, Paulo; Šeput, Miranda

    2016-04-01

    Soil organic carbon (SOC), pH, available phosphorus (P), and potassium (K) are some of the most important factors to soil fertility. These soil parameters are highly variable in space and time, with implications to crop production. The aim of this work is study the spatial variability of SOC, pH, P and K in an organic farm located in river Rasa valley (Croatia). A regular grid (100 x 100 m) was designed and 182 samples were collected on Silty Clay Loam soil. P, K and SOC showed moderate heterogeneity with coefficient of variation (CV) of 21.6%, 32.8% and 51.9%, respectively. Soil pH record low spatial variability with CV of 1.5%. Soil pH, P and SOC did not follow normal distribution. Only after a Box-Cox transformation, data respected the normality requirements. Directional exponential models were the best fitted and used to describe spatial autocorrelation. Soil pH, P and SOC showed strong spatial dependence with nugget to sill ratio with 13.78%, 0.00% and 20.29%, respectively. Only K recorded moderate spatial dependence. Semivariogram ranges indicate that future sampling interval could be 150 - 200 m in order to reduce sampling costs. Fourteen different interpolation models for mapping soil properties were tested. The method with lowest Root Mean Square Error was the most appropriated to map the variable. The results showed that radial basis function models (Spline with Tension and Completely Regularized Spline) for P and K were the best predictors, while Thin Plate Spline and inverse distance weighting models were the least accurate. The best interpolator for pH and SOC was the local polynomial with the power of 1, while the least accurate were Thin Plate Spline. According to soil nutrient maps investigated area record very rich supply with K while P supply was insufficient on largest part of area. Soil pH maps showed mostly neutral reaction while individual parts of alkaline soil indicate the possibility of penetration of seawater and salt accumulation in the

  6. Root carbon inputs to the rhizosphere stimulate extracellular enzyme activity and increase nitrogen availability in temperate forest soils

    Science.gov (United States)

    Brzostek, E. R.; Phillips, R.; Dragoni, D.; Drake, J. E.; Finzi, A. C.

    2011-12-01

    The mobilization of nitrogen (N) from soil organic matter in temperate forest soils is controlled by the microbial production and activity of extracellular enzymes. The exudation of carbon (C) by tree roots into the rhizosphere may subsidize the microbial production of extracellular enzymes in the rhizosphere and increase the access of roots to N. The objective of this research was to investigate whether rates of root exudation and the resulting stimulation of extracellular enzyme activity in the rhizosphere (i.e., rhizosphere effect) differs between tree species that form associations with ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi. This research was conducted at two temperate forest sites, the Harvard Forest (HF) in Central MA and the Morgan Monroe State Forest (MMSF) in Southern IN. At the HF, we measured rates of root exudation and the rhizosphere effects on enzyme activity, N cycling, and C mineralization in AM and ECM soils. At the MMSF, we recently girdled AM and ECM dominated plots to examine the impact of severing belowground C allocation on rhizosphere processes. At both sites, the rhizosphere effect on proteolytic, chitinolytic and ligninolytic enzyme activities was greater in ECM soils than in AM soils. In particular, higher rates of proteolytic enzyme activity increased the availability of amino acid-N in ECM rhizospheres relative to the bulk soils. Further, this stimulation of enzyme activity was directly correlated with higher rates of C mineralization in the rhizosphere than in the bulk soil. Although not significantly different between species, root exudation of C comprised 3-10% of annual gross primary production at the HF. At the MMSF, experimental girdling led to a larger decline in soil respiration and enzyme activity in ECM plots than in AM plots. In both ECM and AM soils, however, girdling resulted in equivalent rates of enzyme activity in rhizosphere and corresponding bulk soils. The results of this study contribute to the

  7. Low-Z material for limiters and wall surfaces in JET: beryllium and carbon

    International Nuclear Information System (INIS)

    Rebut, P.H.; Hugon, M.; Booth, S.J.; Dean, J.R.; Dietz, K.J.; Sonnenberg, K.; Watkins, M.L.

    1985-01-01

    The relative merits of graphite and beryllium, as a low-Z material for limiters and wall surfaces in JET, are compared. A consideration of data on thermomechanical properties, retention of hydrogen and gettering action, indicates that beryllium offers the best prospects as a material for the JET belt limiters and walls. (U.K.)

  8. Soil carbon, after 3 years, under short-rotation woody crops grown under varying nutrient and water availability

    Science.gov (United States)

    Felipe G. Sanchez; Mark Coleman; Charles T. Garten; Robert J. Luxmoore; John A. Stanturf; Carl Trettin; Stan D. Wullschleger

    2007-01-01

    Soil carbon contents were measured on a short-rotation woody crop study located on the US Department of Energy's Savannah River Site outside Aiken, SC. This study included fertilization and irrigation treatments on five tree genotypes (sweetgum, loblolly pine, sycamore and two eastern cottonwood clones). Prior to study installation, the previous pine stand was...

  9. Transportation Energy Futures Series: Alternative Fuel Infrastructure Expansion: Costs, Resources, Production Capacity, and Retail Availability for Low-Carbon Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, M. W.; Heath, G.; Sandor, D.; Steward, D.; Vimmerstedt, L.; Warner, E.; Webster, K. W.

    2013-04-01

    Achieving the Department of Energy target of an 80% reduction in greenhouse gas emissions by 2050 depends on transportation-related strategies combining technology innovation, market adoption, and changes in consumer behavior. This study examines expanding low-carbon transportation fuel infrastructure to achieve deep GHG emissions reductions, with an emphasis on fuel production facilities and retail components serving light-duty vehicles. Three distinct low-carbon fuel supply scenarios are examined: Portfolio: Successful deployment of a range of advanced vehicle and fuel technologies; Combustion: Market dominance by hybridized internal combustion engine vehicles fueled by advanced biofuels and natural gas; Electrification: Market dominance by electric drive vehicles in the LDV sector, including battery electric, plug-in hybrid, and fuel cell vehicles, that are fueled by low-carbon electricity and hydrogen. A range of possible low-carbon fuel demand outcomes are explored in terms of the scale and scope of infrastructure expansion requirements and evaluated based on fuel costs, energy resource utilization, fuel production infrastructure expansion, and retail infrastructure expansion for LDVs. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored transportation-related strategies for abating GHGs and reducing petroleum dependence.

  10. Fabrication of Stretchable Copper Coated Carbon Nanotube Conductor for Non-Enzymatic Glucose Detection Electrode with Low Detection Limit and Selectivity

    Directory of Open Access Journals (Sweden)

    Dawei Jiang

    2018-03-01

    Full Text Available The increasing demand for wearable glucose sensing has stimulated growing interest in stretchable electrodes. The development of the electrode materials having large stretchability, low detection limit, and good selectivity is the key component for constructing high performance wearable glucose sensors. In this work, we presented fabrication of stretchable conductor based on the copper coated carbon nanotube sheath-core fiber, and its application as non-enzymatic electrode for glucose detection with high stretchability, low detection limit, and selectivity. The sheath-core fiber was fabricated by coating copper coated carbon nanotube on a pre-stretched rubber fiber core followed by release of pre-stretch, which had a hierarchically buckled structure. It showed a small resistance change as low as 27% as strain increasing from 0% to 500% strain, and a low resistance of 0.4 Ω·cm−1 at strain of 500%. This electrode showed linear glucose concentration detection in the range between 0.05 mM and 5 mM and good selectivity against sucrose, lactic acid, uric acid, acrylic acid in phosphate buffer saline solution, and showed stable signal in high salt concentration. The limit of detection (LOD was 0.05 mM, for the range of 0.05–5 mM, the sensitivity is 46 mA·M−1. This electrode can withstand large strain of up to 60% with negligible influence on its performance.

  11. The limits to global-warming mitigation by terrestrial carbon removal

    Science.gov (United States)

    Boysen, Lena R.; Lucht, Wolfgang; Gerten, Dieter; Heck, Vera; Lenton, Timothy M.; Schellnhuber, Hans Joachim

    2017-05-01

    Massive near-term greenhouse gas emissions reduction is a precondition for staying "well below 2°C" global warming as envisaged by the Paris Agreement. Furthermore, extensive terrestrial carbon dioxide removal (tCDR) through managed biomass growth and subsequent carbon capture and storage is required to avoid temperature "overshoot" in most pertinent scenarios. Here, we address two major issues: First, we calculate the extent of tCDR required to "repair" delayed or insufficient emissions reduction policies unable to prevent global mean temperature rise of 2.5°C or even 4.5°C above pre-industrial level. Our results show that those tCDR measures are unable to counteract "business-as-usual" emissions without eliminating virtually all natural ecosystems. Even if considerable (Representative Concentration Pathway 4.5 [RCP4.5]) emissions reductions are assumed, tCDR with 50% storage efficiency requires >1.1 Gha of the most productive agricultural areas or the elimination of >50% of natural forests. In addition, >100 MtN/yr fertilizers would be needed to remove the roughly 320 GtC foreseen in these scenarios. Such interventions would severely compromise food production and/or biosphere functioning. Second, we reanalyze the requirements for achieving the 160-190 GtC tCDR that would complement strong mitigation action (RCP2.6) in order to avoid 2°C overshoot anytime. We find that a combination of high irrigation water input and/or more efficient conversion to stored carbon is necessary. In the face of severe trade-offs with society and the biosphere, we conclude that large-scale tCDR is not a viable alternative to aggressive emissions reduction. However, we argue that tCDR might serve as a valuable "supporting actor" for strong mitigation if sustainable schemes are established immediately.

  12. Role of forest sector and bioenergy in limiting the carbon emissions of Finland

    International Nuclear Information System (INIS)

    Pingoud, Kim; Lehtilae, Antti

    1997-01-01

    The greenhouse impacts of the Finnish forest sector, including the forests biomass, forest industry, forest products in use, foreign trade and waste management are discussed. The main carbon storages and flows are estimated and the greenhouse gas balance both totally and on national level are presented. The history of the greenhouse impact is also estimated and two future scenarios of the forest sector are compared. The present use and potential for additional use of bioenergy is also reviewed, and the impact of expanded bioenergy use on the national CO 2 emissions is illustrated with scenario examples. (author)

  13. Lower limits of detection in using carbon nanotubes as thermoluminescent dosimeters of beta radiation

    Science.gov (United States)

    Alanazi, Abdulaziz; Jurewicz, Izabela; Alalawi, Amani I.; Alyahyawi, Amjad; Alsubaie, Abdullah; Hinder, Steven; Bañuls-Ciscar, Jorge; Alkhorayef, Mohammed; Bradley, D. A.

    2017-11-01

    World-wide, on-going intensive research is being seen in adaptation of carbon nanotubes (CNTs) for a wide variety of applications, particular interest herein being in the thermoluminescent (TL) properties of CNTs and their sensitivity towards energetic radiations. Using beta radiation delivering dose levels of a few Gy it has been observed in previous study that strain and impurity defects in CNTs give rise to significant TL yields, providing an initial measure of the extent to which electron trapping centres exist in various qualities of CNT, from super-pure to raw. This in turn points to the possibility that there may be considerable advantage in using such media for radiation dosimetry applications, including for in vivo dosimetry. CNTs also have an effective atomic number similar to that of adipose tissue, making them suitable for soft tissue dosimetry. In present investigations various single-wall carbon nanotubes (SWCNT) samples in the form of buckypaper have been irradiated to doses in the range 35-1.3 Gy, use being made of a 90Sr beta source, the response of the CNTs buckypaper with dose showing a trend towards linearity. It is shown for present production methodology for buckypaper samples that the raw SWCNT buckypaper offer the greatest sensitivity, detecting doses down to some few tens of mGy.

  14. Limited contribution of permafrost carbon to methane release from thawing peatlands

    Science.gov (United States)

    Cooper, Mark D. A.; Estop-Aragonés, Cristian; Fisher, James P.; Thierry, Aaron; Garnett, Mark H.; Charman, Dan J.; Murton, Julian B.; Phoenix, Gareth K.; Treharne, Rachael; Kokelj, Steve V.; Wolfe, Stephen A.; Lewkowicz, Antoni G.; Williams, Mathew; Hartley, Iain P.

    2017-07-01

    Models predict that thaw of permafrost soils at northern high latitudes will release tens of billions of tonnes of carbon (C) to the atmosphere by 2100 (refs ,,). The effect on the Earth’s climate depends strongly on the proportion of this C that is released as the more powerful greenhouse gas methane (CH4), rather than carbon dioxide (CO2) (refs ,); even if CH4 emissions represent just 2% of the C release, they would contribute approximately one-quarter of the climate forcing. In northern peatlands, thaw of ice-rich permafrost causes surface subsidence (thermokarst) and water-logging, exposing substantial stores (tens of kilograms of C per square meter, ref. ) of previously frozen organic matter to anaerobic conditions, and generating ideal conditions for permafrost-derived CH4 release. Here we show that, contrary to expectations, although substantial CH4 fluxes (>20 g CH4 m-2 yr-1) were recorded from thawing peatlands in northern Canada, only a small amount was derived from previously frozen C (effect of permafrost thaw on CH4 emissions from northern peatlands.

  15. Equilibrium Limit of Boundary Scattering in Carbon Nanostructures: Molecular Dynamics Calculations of Thermal Transport

    Science.gov (United States)

    Haskins, Justin; Kinaci, Alper; Sevik, Cem; Cagin, Tahir

    2012-01-01

    It is widely known that graphene and many of its derivative nanostructures have exceedingly high reported thermal conductivities (up to 4000 W/mK at 300 K). Such attractive thermal properties beg the use of these structures in practical devices; however, to implement these materials while preserving transport quality, the influence of structure on thermal conductivity should be thoroughly understood. For graphene nanostructures, having average phonon mean free paths on the order of one micron, a primary concern is how size influences the potential for heat conduction. To investigate this, we employ a novel technique to evaluate the lattice thermal conductivity from the Green-Kubo relations and equilibrium molecular dynamics in systems where phonon-boundary scattering dominates heat flow. Specifically, the thermal conductivities of graphene nanoribbons and carbon nanotubes are calculated in sizes up to 3 microns, and the relative influence of boundary scattering on thermal transport is determined to be dominant at sizes less than 1 micron, after which the thermal transport largely depends on the quality of the nanostructure interface. The method is also extended to carbon nanostructures (fullerenes) where phonon confinement, as opposed to boundary scattering, dominates, and general trends related to the influence of curvature on thermal transport in these materials are discussed.

  16. Use of activated carbon as a support medium for H2S biofiltration and effect of bacterial immobilization on available pore surface.

    Science.gov (United States)

    Ng, Y L; Yan, R; Chen, X G; Geng, A L; Gould, W D; Liang, D T; Koe, L C C

    2004-12-01

    The use of support media for the immobilization of microorganisms is widely known to provide a surface for microbial growth and a shelter that protects the microorganisms from inhibitory compounds. In this study, activated carbon is used as a support medium for the immobilization of microorganisms enriched from municipal sewage activated sludge to remove gas-phase hydrogen sulfide (H2S), a major odorous component of waste gas from sewage treatment plants. A series of designed experiments is used to examine the effect on bacteria-immobilized activated carbon (termed "biocarbon") due to physical adsorption, chemical reaction, and microbial degradation in the overall removal of H2S. H2S breakthrough tests are conducted with various samples, including microbe-immobilized carbon and Teflon discs, salts-medium-washed carbon, and ultra-pure water-washed carbon. The results show a higher removal capacity for the microbe-immobilized activated carbon compared with the activated carbon control in a batch biofilter column. The increase in removal capacity is attributed to the role played by the immobilized microorganisms in metabolizing adsorbed sulfur and sulfur compounds on the biocarbon, hence releasing the adsorption sites for further H2S uptake. The advantage for activated carbon serving as the support medium is to adsorb a high initial concentration of substrate and progressively release this for microbial degradation, hence acting as a buffer for the microorganisms. Results obtained from surface area and pore size distribution analyses of the biocarbon show a correlation between the available surface area and pore volume with the extent of microbial immobilization and H2S uptake. The depletion of surface area and pore volume is seen as one of the factors which cause the onset of column breakthrough. Microbial growth retardation is due to the accumulation of metabolic products (i.e., sulfuric acid); and a lack of water and nutrient salts in the batch biofilter are other

  17. Descriptors and Thermodynamic Limitations of Electrocatalytic Carbon Dioxide Reduction on Rutile Oxide Surfaces

    DEFF Research Database (Denmark)

    Bhowmik, Arghya; Vegge, Tejs; Hansen, Heine Anton

    2016-01-01

    A detailed understanding of the electrochemical reduction of CO2 into liquid fuels on rutile metal oxide surfaces is developed by using DFT calculations. We consider oxide overlayer structures on RuO2(1 1 0) surfaces as model catalysts to elucidate the trends and limitations in the CO2 reduction...... and it defines the left leg of the activity volcano for CO2RR. HCOOH* is a key intermediate for products formed through further reduction, for example, methanediol, methanol, and methane. The surfaces that do not bind HCOOH* are selective towards formic acid (HCOOH) production, but hydrogen evolution limits...

  18. The accuracy and limitations of a new meter used to measure aqueous carbon dioxide

    DEFF Research Database (Denmark)

    Moran, Damian; Tirsgård, Bjørn; Steffensen, John F.

    2010-01-01

    The OxyGuard CO2 Analyzer is a novel meter that can directly measure aqueous CO2 gas pressure using a water-resistant gas-permeable membrane and infra-red absorption cell. The pCO2 is converted to a concentration via a solubility factor determined from the calibration procedure and a thermistor. We...... not appreciably affect reaction time. The meter had a precision of ±0.5 mg L−1 CO2(aq), and high linearity (correlation 0.99–1.01) above 1 mg L−1 in both freshwater and seawater. The standard meter will not be useful for measuring low concentrations such as atmospheric CO2 levels, but will be useful in situations...... where accurate pH and carbonate alkalinity determinations are difficult to obtain, such as saline waters and waters of high organic loadings....

  19. Limits to co-combustion of coal and eucalyptus due to water availability in the state of Rio Grande do Sul, Brazil

    International Nuclear Information System (INIS)

    Hoffmann, Bettina Susanne; Szklo, Alexandre; Schaeffer, Roberto

    2014-01-01

    Highlights: • Brazil holds reserves of high ash coal that can only be used in mine-mouth plants. • Water scarcity requires the use of wet or dry cooling systems in several regions. • The co-firing of 30 wt% eucalyptus is possible regarding the biomass availability. • Biomass cultivation would aggravate the water scarcity in several regions. - Abstract: Brazil has favorable edaphoclimatic conditions for the cultivation of biomass for energy. On the other hand, the country plans to expand its thermal power park using fossil fuels, including Brazil’s high ash coal. This study estimates the potential of co-firing biomass from energy forests in power plants fired with Brazilian coal in the state of Rio Grande do Sul, Brazil, focusing on the limits given by biomass and water availability. Results show that the state holds coal reserves that could support a potential of approximately 8 GW. Referring to limits due to water availability, different outcomes were found for the various coal fields in Rio Grande do Sul. The Candiota coal field, which represents the most important coal field, holding a capacity of 4 GW, shows severe restrictions for water availability that would be aggravated by intense eucalyptus cultivation

  20. Nitrogen fertilization decouples roots and microbes: Reductions in belowground carbon allocation limit microbial activity

    Science.gov (United States)

    Carrara, J.; Walter, C. A.; Govindarajulu, R.; Hawkins, J.; Brzostek, E. R.

    2017-12-01

    Nitrogen (N) deposition has enhanced the ability of trees to capture atmospheric carbon (C). The effect of elevated N on belowground C cycling, however, is variable and response mechanisms are largely unknown. Recent research has highlighted distinct differences between ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) trees in the strength of root-microbial interactions. In particular, ECM trees send more C to rhizosphere microbes to stimulate enzyme activity and nutrient mobilization than AM trees, which primarily rely on saprotrophic microbes to mobilize N. As such, we hypothesized that N fertilization would weaken root-microbial interactions and soil decomposition in ECM stands more than in AM stands. To test this hypothesis, we measured root-microbial interactions in ECM and AM plots in two long-term N fertilization studies, the Fernow Experimental Forest, WV and Bear Brook Watershed, ME. We found that N fertilization led to declines in plant C allocation belowground to fine root biomass, branching, and root exudation in ECM stands to a greater extent than in AM stands. As ECM roots are tightly coupled to the soil microbiome through energy and nutrient exchange, reductions in belowground C allocation were mirrored by shifts in microbial community composition and reductions in fungal gene expression. These shifts were accompanied by larger reductions in fungal-derived lignolytic and hydrolytic enzyme activity in ECM stands than in AM stands. In contrast, as the AM soil microbiome is less reliant on trees for C and are more adapted to high inorganic nutrient environments, the soil metagenome and transcriptome were more resilient to decreases in belowground C allocation. Collectively, our results indicate the N fertilization decoupled root-microbial interactions by reducing belowground carbon allocation in ECM stands. Thus, N fertilization may reduce soil turnover and increase soil C storage to a greater extent in forests dominated by ECM than AM trees.

  1. Operational Limitations of Arctic Waste Stabilization Ponds: Insights from Modeling Oxygen Dynamics and Carbon Removal

    DEFF Research Database (Denmark)

    Ragush, Colin M.; Gentleman, Wendy C.; Hansen, Lisbeth Truelstrup

    2018-01-01

    Presented here is a mechanistic model of the biological dynamics of the photic zone of a single-cell arctic waste stabilization pond (WSP) for the prediction of oxygen concentration and the removal of oxygen-demanding substances. The model is an exploratory model to assess the limiting environmen...

  2. Accelerated carbonation testing of mortar with supplementary cement materials. Limitation of the acceleration due to drying

    NARCIS (Netherlands)

    Visser, J.H.M.

    2012-01-01

    In the design stage of a concrete structure, decisions have to be made on how to fulfil the required service life and consequently, what concrete composition to use. Concrete compositions can be chosen on account of known performances but this will limit the choice of compositions and materials to

  3. A Dramatic Classroom Demonstration of Limiting Reagent Using the Vinegar and Sodium Hydrogen Carbonate Reaction

    Science.gov (United States)

    Artdej, Romklao; Thongpanchang, Tienthong

    2008-01-01

    This demonstration is designed to illustrate the concept of limiting reagent in a spectacular way. Via a series of experiments where the amount of vinegar is fixed and the amount of NaHCO[subscript 3] is gradually increased, the volume of CO[subscript 2] generated from the reaction varies corresponding to the amount of NaHCO[subscript 3] until it…

  4. Insights from a network of long-term measurements of biosphere-atmospheric exchanges of water vapor and carbon dioxide in a water-limited semiarid region

    Science.gov (United States)

    Scott, Russell; Biederman, Joel

    2017-04-01

    Around one-third of Earth's land surface is classified as semiarid, and carbon dioxide exchange in these regions has been shown to be an important regulator of both the trend and interannual variability of the terrestrial carbon sink. Fifteen years ago, when we began making measurements of biosphere-atmospheric exchanges of energy, water vapor, and carbon dioxide using eddy covariance in southern Arizona USA, there was paucity of semiarid observations in flux networks like AmeriFlux and EuroFlux. We started by establishing riparian sites across a woody plant encroachment gradient to quantify the productivity and consumptive plant water use along a iconic and ecologically important desert river. Soon thereafter, we added semiarid grassland, shrubland, and savanna sites that do not have access to groundwater in order to better understand how water limitation and changes in vegetation structure affect ecosystem productivity. Here, we highlight the value of multiyear, multisite flux data for addressing regional to global scale problems associated with groundwater pumping, land cover change, drought, and climate change. For the riparian sites, we find that ecosystem water availability is altered by vegetation structure such that ecosystems with more deeply rooted trees have higher productivity but at a cost of greater groundwater use. For the non-riparian sites, precipitation strongly controls ecosystem water availability and the resultant productivity, but differences in ecosystem structure impact water use efficiency due to the partitioning of evapotranspiration into its component sources. Also, the productivity at sites with more grass, and less woody, plants responds more quickly to precipitation fluctuations including long-term drought conditions. In semiarid regions, variability in water and carbon fluxes is much larger than in more mesic climes. Across our riparian and non-riparian sites, access to more stable groundwater reserves reduces variability in water and

  5. The composition of readily available carbon sources produced by fermentation of fish faeces is affected by dietary protein:energy ratios

    DEFF Research Database (Denmark)

    Letelier-Gordo, Carlos Octavio; Larsen, Bodil Katrine; Dalsgaard, Johanne

    2017-01-01

    , 17, 19, 21 and 23 g/MJ) to rainbow trout (Oncorhynchus mykiss) on the production of volatile fatty acids (VFAs) and ethanol during 7 days fermentation of the produced fish faeces. The total yields of VFAs and ethanol obtained (expressed as chemical oxygen demand (COD)) ranged between 0.21–0.24 g...... of acetic and valeric acid. Changing the diet composition thus affects the composition of readily available carbon that can be derived from the faeces. This can be applied to enhance on-farm single sludge denitrification and reduce the need for adding external carbon sources such as e.g. methanol....

  6. Effects of antifreezes and bundled material on the stability and optical limiting in aqueous suspensions of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Vlasov, Andrey Yu.; Venediktova, Anastasia V.; Sokolova, Ekaterina P. [Department of Chemistry, St. Petersburg State University, Universitetsky Pr. 26, St. Petersburg 198504 (Russian Federation); Videnichev, Dmitry A. [S.I. Vavilov State Optical Institute, Birzhevaya line 12, St. Petersburg 199034 (Russian Federation); St. Petersburg National Research University ITMO, Kronverksky pr. 49, St. Petersburg 197101 (Russian Federation); Lasers and Optical Systems JSC, Birzhevaya line 12, St. Petersburg 199034 (Russian Federation); Kislyakov, Ivan M. [S.I. Vavilov State Optical Institute, Birzhevaya line 12, St. Petersburg 199034 (Russian Federation); St. Petersburg National Research University ITMO, Kronverksky pr. 49, St. Petersburg 197101 (Russian Federation); Obraztsova, Elena D. [A.M. Prokhorov Institute of General Physics, Russian Academy of Sciences, Vavilov Str. 38, Moscow 119991 (Russian Federation)

    2012-12-15

    This work gives data on the stability of dispersions of single wall carbon nanotubes stabilized by sodium dodecylbenzenesulfonate in binary polar solvents ''water + antifreeze'' (glycerol, polyethyleneglycole) with eutectic compositions. The absorption spectra of the suspensions demonstrate no changes during 1-year storage with temperature spanning from -40 to +40 C. The systems provide relevant optical power limiting properties, the one with glycerol showing good resistance to optical bleaching effects. We also demonstrate that aqueous dispersions of nanotubes exhibit considerable enhancement of optical limiting parameters alongside an increase of the bundled material populace. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Why Seedlings Die: Linking Carbon and Water Limitations to Mechanisms of Mortality During Establishment in Conifer Seedlings

    Science.gov (United States)

    Reinhardt, K.; Germino, M. J.; Kueppers, L. M.; Mitton, J.; Castanha, C.

    2012-12-01

    BACKGROUND Recent ecophysiological studies aimed at explaining adult tree mortality during drought have examined the carbon (C)-exhaustion compared to the hydraulic-failure hypotheses for death. Prolonged drought leads to durations of stomatal closure (and thus limited C gain), which could result in long periods of negative C balance and fatal reductions in whole-plant C reserves (i.e., available non-structural carbohydrates ["NSC"]). Alternatively, C reserves may not decrease much but could become increasingly inaccessible to sink tissues in long dry-periods due to impediments to translocation of photosynthate (e.g., through disruption of hydrostatic pressure flow in phloem). As C reserves decline or become inaccessible, continued maintenance respiration has been hypothesized to lead to exhaustion of NSC after extended durations of drought, especially in isohydric plant species. On the other hand, hydraulic failure (e.g., catastrophic xylem embolisms) during drought may be the proximate cause of death, occurring before true C starvation occurs. Few studies have investigated specifically the mechanism(s) of tree death, and no published studies that we know of have quantified changes in NSC during mortality. EXPERIMENTAL DESIGN AND HYPOTHESES We conducted two studies that investigated whole-tree and tissue-specific C relations (photosynthetic C gain, respiration, dry-mass gain, and NSC pools) in Pinus flexilis seedlings during the initial establishment phase, which is characterized by progressive drought during summer. We measured survival, growth and biomass allocation, and C-balance physiology (photosynthetic C-gain and chlorophyll fluorescence, respiration C-use, and NSC concentrations) from germination to mortality. We hypothesized that 1) stomatal and biochemical limitations to C gain would constrain seedling survival (through inadequate seasonal C-balance), as has been shown for conifer seedlings near alpine treeline; 2) hydraulic constraints (embolisms and

  8. 40 CFR Table 5 to Subpart Bbbb of... - Model Rule-Carbon Monoxide Emission Limits for Existing Small Municipal Waste Combustion Units

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Model Rule-Carbon Monoxide Emission... BBBB of Part 60—Model Rule—Carbon Monoxide Emission Limits for Existing Small Municipal Waste... PERFORMANCE FOR NEW STATIONARY SOURCES Emission Guidelines and Compliance Times for Small Municipal Waste...

  9. 75 FR 32160 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products from Brazil: Extension of Time Limit...

    Science.gov (United States)

    2010-06-07

    ...-Rolled Carbon-Quality Steel Products from Brazil: Extension of Time Limit for Preliminary Results of...-quality steel products from Brazil. See Agreement Suspending the Countervailing Duty Investigation on Hot... duty order on certain hot-rolled flat-rolled carbon-quality steel products from Brazil. See Initiation...

  10. Comparing PAH availability from manufactured gas plant soils and sediments with chemical and biological tests. 1. PAH release during water desorption and supercritical carbon dioxide extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, S.B.; Poppendieck, D.G.; Grabanski, C.B.; Loehr, R.C. [University of North Dakota, Grand Forks, ND (US). Energy and Environmental Research Center

    2002-11-15

    Soil and sediment samples from OG (oil gas) and CG (coal gas) manufactured gas plant (MGP) sites in the United States that had been closed for about 50 years were selected to represent a range of PAH concentrations and sample matrix compositions. Samples varied from vegetated soils to lampblack soot and had carbon contents from 3 to 87 wt%. Supercritical carbon dioxide, SFE desorption and water/XAD{sub 2} desorption curves were determined and fit with a simple two-site model to determine the rapid-released fraction (F) for PAHs ranging from naphthalene to benzo-(ghi)perylene. F values varied greatly among the samples. Release rates did not correlate with sample matrix characteristics including PAH concentrations, elemental composition or 'hard' and 'soft' organic carbon, indicating that PAH release cannot easily be estimated on the basis of sample matrix composition. F values for CG site samples obtained with SFE and water desorption agreed well but SFE yielded higher F values for the OG samples. These behaviors were attributed to the stronger ability of carbon dioxide than water to desorb PAHs from the highly aromatic (hard) carbon of the OG matrixes, while carbon dioxide and water showed similar abilities to desorb PAHs from the more polar (soft) carbon of the CG samples. The combined SFE and water desorption approaches should improve the understanding of PAH sequestration and release from contaminated soils and sediments and provide the basis for subsequent studies, using the same samples to compare PAH release with PAH availability to earthworms. 46 refs., 4 figs., 4 tabs.

  11. Multi-model analysis of terrestrial carbon cycles in Japan: limitations and implications of model calibration using eddy flux observations

    Directory of Open Access Journals (Sweden)

    K. Ichii

    2010-07-01

    Full Text Available Terrestrial biosphere models show large differences when simulating carbon and water cycles, and reducing these differences is a priority for developing more accurate estimates of the condition of terrestrial ecosystems and future climate change. To reduce uncertainties and improve the understanding of their carbon budgets, we investigated the utility of the eddy flux datasets to improve model simulations and reduce variabilities among multi-model outputs of terrestrial biosphere models in Japan. Using 9 terrestrial biosphere models (Support Vector Machine – based regressions, TOPS, CASA, VISIT, Biome-BGC, DAYCENT, SEIB, LPJ, and TRIFFID, we conducted two simulations: (1 point simulations at four eddy flux sites in Japan and (2 spatial simulations for Japan with a default model (based on original settings and a modified model (based on model parameter tuning using eddy flux data. Generally, models using default model settings showed large deviations in model outputs from observation with large model-by-model variability. However, after we calibrated the model parameters using eddy flux data (GPP, RE and NEP, most models successfully simulated seasonal variations in the carbon cycle, with less variability among models. We also found that interannual variations in the carbon cycle are mostly consistent among models and observations. Spatial analysis also showed a large reduction in the variability among model outputs. This study demonstrated that careful validation and calibration of models with available eddy flux data reduced model-by-model differences. Yet, site history, analysis of model structure changes, and more objective procedure of model calibration should be included in the further analysis.

  12. Pt deposition on carbon paper and Ti mesh substrates by surface limited redox replacement

    CSIR Research Space (South Africa)

    Modibedi, M

    2011-12-01

    Full Text Available , the material used as gas diffusion layer for proton exchange membrane fuel cells (PEMFCs) and Ti-mesh. The deposition uses multiple redox replacement of underpotentially deposited Cu used as a sacrificial metal. The morphology and particle size of the deposited...

  13. Multi-model analysis of terrestrial carbon cycles in Japan: limitations and implications of model calibration using eddy flux observations

    Science.gov (United States)

    Ichii, K.; Suzuki, T.; Kato, T.; Ito, A.; Hajima, T.; Ueyama, M.; Sasai, T.; Hirata, R.; Saigusa, N.; Ohtani, Y.; Takagi, K.

    2010-07-01

    Terrestrial biosphere models show large differences when simulating carbon and water cycles, and reducing these differences is a priority for developing more accurate estimates of the condition of terrestrial ecosystems and future climate change. To reduce uncertainties and improve the understanding of their carbon budgets, we investigated the utility of the eddy flux datasets to improve model simulations and reduce variabilities among multi-model outputs of terrestrial biosphere models in Japan. Using 9 terrestrial biosphere models (Support Vector Machine - based regressions, TOPS, CASA, VISIT, Biome-BGC, DAYCENT, SEIB, LPJ, and TRIFFID), we conducted two simulations: (1) point simulations at four eddy flux sites in Japan and (2) spatial simulations for Japan with a default model (based on original settings) and a modified model (based on model parameter tuning using eddy flux data). Generally, models using default model settings showed large deviations in model outputs from observation with large model-by-model variability. However, after we calibrated the model parameters using eddy flux data (GPP, RE and NEP), most models successfully simulated seasonal variations in the carbon cycle, with less variability among models. We also found that interannual variations in the carbon cycle are mostly consistent among models and observations. Spatial analysis also showed a large reduction in the variability among model outputs. This study demonstrated that careful validation and calibration of models with available eddy flux data reduced model-by-model differences. Yet, site history, analysis of model structure changes, and more objective procedure of model calibration should be included in the further analysis.

  14. Comparing PAH availability from manufactured gas plant soils and sediments with chemical and biological tests. 1. PAH release during water desorption and supercritical carbon dioxide extraction.

    Science.gov (United States)

    Hawthorne, Steven B; Poppendieck, Dustin G; Grabanski, Carol B; Loehr, Raymond C

    2002-11-15

    Soil and sediment samples from oil gas (OG) and coal gas (CG) manufactured gas plant (MGP) sites were selected to represent a range of PAH concentrations (150-40,000 mg/kg) and sample matrix compositions. Samples varied from vegetated soils to lampblack soot and had carbon contents from 3 to 87 wt %. SFE desorption (120 min) and water/XAD2 desorption (120 days) curves were determined and fit with a simple two-site model to determine the rapid-released fraction (F) for PAHs ranging from naphthalene to benzo[ghi]perylene. F values varied greatly among the samples, from ca. 10% to >90% for the two- and three-ring PAHs and from <1% to ca. 50% for the five- and six-ring PAHs. Release rates did not correlate with sample matrix characteristics including PAH concentrations, elemental composition (C, H, N, S), or "hard" and "softs" organic carbon, indicating that PAH release cannot easily be estimated on the basis of sample matrix composition. Fvalues for CG site samples obtained with SFE and water desorption agreed well (linear correlation coefficient, r2 = 0.87, slope = 0.93), but SFE yielded higher F values for the OG samples. These behaviors were attributed to the stronger ability of carbon dioxide than water to desorb PAHs from the highly aromatic (hard) carbon of the OG matrixes, while carbon dioxide and water showed similar abilities to desorb PAHs from the more polar (soft) carbon of the CG samples. The combined SFE and water desorption approaches should improve the understanding of PAH sequestration and release from contaminated soils and sediments and provide the basis for subsequent studies using the same samples to compare PAH release with PAH availability to earthworms.

  15. The physiological response of two green calcifying algae from the Great Barrier Reef towards high dissolved inorganic and organic carbon (DIC and DOC availability.

    Directory of Open Access Journals (Sweden)

    Friedrich Wilhelm Meyer

    Full Text Available Increasing dissolved inorganic carbon (DIC concentrations associated with ocean acidification can affect marine calcifiers, but local factors, such as high dissolved organic carbon (DOC concentrations through sewage and algal blooms, may interact with this global factor. For calcifying green algae of the genus Halimeda, a key tropical carbonate producer that often occurs in coral reefs, no studies on these interactions have been reported. These data are however urgently needed to understand future carbonate production. Thus, we investigated the independent and combined effects of DIC (pCO2 402 μatm/ pHtot 8.0 and 996 μatm/ pHtot 7.7 and DOC (added as glucose in 0 and 294 μmol L-1 on growth, calcification and photosynthesis of H. macroloba and H. opuntia from the Great Barrier Reef in an incubation experiment over 16 days. High DIC concentrations significantly reduced dark calcification of H. opuntia by 130 % and led to net dissolution, but did not affect H. macroloba. High DOC concentrations significantly reduced daily oxygen production of H. opuntia and H. macroloba by 78 % and 43 %, respectively, and significantly reduced dark calcification of H. opuntia by 70%. Combined high DIC and DOC did not show any interactive effects for both algae, but revealed additive effects for H. opuntia where the combination of both factors reduced dark calcification by 162 % compared to controls. Such species-specific differences in treatment responses indicate H. opuntia is more susceptible to a combination of high DIC and DOC than H. macroloba. From an ecological perspective, results further suggest a reduction of primary production for Halimeda-dominated benthic reef communities under high DOC concentrations and additional decreases of carbonate accretion under elevated DIC concentrations, where H. opuntia dominates the benthic community. This may reduce biogenic carbonate sedimentation rates and hence the buffering capacity against further ocean

  16. Increased iron availability resulting from increased CO2 enhances carbon and nitrogen metabolism in the economical marine red macroalga Pyropia haitanensis (Rhodophyta).

    Science.gov (United States)

    Chen, Binbin; Zou, Dinghui; Yang, Yufeng

    2017-04-01

    Ocean acidification caused by rising CO 2 is predicted to increase the concentrations of dissolved species of Fe(II) and Fe(III), leading to the enhanced photosynthetic carbon sequestration in some algal species. In this study, the carbon and nitrogen metabolism in responses to increased iron availability under two CO 2 levels (390 μL L -1 and 1000 μL L -1 ), were investigated in the maricultivated macroalga Pyropia haitanensis (Rhodophyta). The results showed that, elevated CO 2 increased soluble carbonhydrate (SC) contents, resulting from enhanced photosynthesis and photosynthetic pigment synthesis in this algae, but declined its soluble protein (SP) contents, resulting in increased ratio of SC/SP. This enhanced photosynthesis performance and carbon accumulation was more significant under iron enrichment condition in seawater, with higher iron uptake rate at high CO 2 level. As a key essential biogenic element for algae, Fe-replete functionally contributed to P. haitanensis photosynthesis. Increased SC fundamentally provided carbon skeletons for nitrogen assimilation. The significant increase of carbon and nitrogen assimilation finally contributed to enhanced growth in this alga. This was also intuitively reflected by respiration that provided energy for cellular metabolism and algal growth. We propose that, in the predicted scenario of rising atmospheric CO 2 , P. haitanensis is capable to adjust its physiology by increasing its carbon and nitrogen metabolism to acclimate the acidified seawater, at the background of global climate change and simultaneously increased iron concentration due to decreased pH levels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. An Assessment of the Commercial Availability of Carbon Dioxide Capture and Storage Technologies as of June 2009

    Energy Technology Data Exchange (ETDEWEB)

    Dooley, James J.; Davidson, Casie L.; Dahowski, Robert T.

    2009-06-26

    Currently, there is considerable confusion within parts of the carbon dioxide capture and storage (CCS) technical and regulatory communities regarding the maturity and commercial readiness of the technologies needed to capture, transport, inject, monitor and verify the efficacy of carbon dioxide (CO2) storage in deep, geologic formations. The purpose of this technical report is to address this confusion by discussing the state of CCS technological readiness in terms of existing commercial deployments of CO2 capture systems, CO2 transportation pipelines, CO2 injection systems and measurement, monitoring and verification (MMV) systems for CO2 injected into deep geologic structures. To date, CO2 has been captured from both natural gas and coal fired commercial power generating facilities, gasification facilities and other industrial processes. Transportation via pipelines and injection of CO2 into the deep subsurface are well established commercial practices with more than 35 years of industrial experience. There are also a wide variety of MMV technologies that have been employed to understand the fate of CO2 injected into the deep subsurface. The four existing end-to-end commercial CCS projects – Sleipner, Snøhvit, In Salah and Weyburn – are using a broad range of these technologies, and prove that, at a high level, geologic CO2 storage technologies are mature and capable of deploying at commercial scales. Whether wide scale deployment of CCS is currently or will soon be a cost-effective means of reducing greenhouse gas emissions is largely a function of climate policies which have yet to be enacted and the public’s willingness to incur costs to avoid dangerous anthropogenic interference with the Earth’s climate. There are significant benefits to be had by continuing to improve through research, development, and demonstration suite of existing CCS technologies. Nonetheless, it is clear that most of the core technologies required to address capture, transport

  18. Prey size and availability limits maximum size of rainbow trout in a large tailwater: insights from a drift-foraging bioenergetics model

    Science.gov (United States)

    Dodrill, Michael J.; Yackulic, Charles B.; Kennedy, Theodore A.; Haye, John W

    2016-01-01

    The cold and clear water conditions present below many large dams create ideal conditions for the development of economically important salmonid fisheries. Many of these tailwater fisheries have experienced declines in the abundance and condition of large trout species, yet the causes of these declines remain uncertain. Here, we develop, assess, and apply a drift-foraging bioenergetics model to identify the factors limiting rainbow trout (Oncorhynchus mykiss) growth in a large tailwater. We explored the relative importance of temperature, prey quantity, and prey size by constructing scenarios where these variables, both singly and in combination, were altered. Predicted growth matched empirical mass-at-age estimates, particularly for younger ages, demonstrating that the model accurately describes how current temperature and prey conditions interact to determine rainbow trout growth. Modeling scenarios that artificially inflated prey size and abundance demonstrate that rainbow trout growth is limited by the scarcity of large prey items and overall prey availability. For example, shifting 10% of the prey biomass to the 13 mm (large) length class, without increasing overall prey biomass, increased lifetime maximum mass of rainbow trout by 88%. Additionally, warmer temperatures resulted in lower predicted growth at current and lower levels of prey availability; however, growth was similar across all temperatures at higher levels of prey availability. Climate change will likely alter flow and temperature regimes in large rivers with corresponding changes to invertebrate prey resources used by fish. Broader application of drift-foraging bioenergetics models to build a mechanistic understanding of how changes to habitat conditions and prey resources affect growth of salmonids will benefit management of tailwater fisheries.

  19. Potential of vehicle-to-grid ancillary services considering the uncertainties in plug-in electric vehicle availability and service/localization limitations in distribution grids

    International Nuclear Information System (INIS)

    Sarabi, Siyamak; Davigny, Arnaud; Courtecuisse, Vincent; Riffonneau, Yann; Robyns, Benoît

    2016-01-01

    Highlights: • The availability uncertainty of PEVs are modelled using Gaussian mixture model. • Interdependency of stochastic variables are modelled using copula function. • V2G bidding capacity is calculated using Free Pattern search optimization method. • Localization limitation is considered for V2G service potential assessment. • Competitive services for fleet of V2G-enabled PEVs are identified using fuzzy sets. - Abstract: The aim of the paper is to propose an approach for statistical assessment of the potential of plug-in electric vehicles (PEV) for vehicle-to-grid (V2G) ancillary services, where it focuses on PEVs doing daily home-work commuting. In this approach, the possible ancillary services (A/S) for each PEV fleet in terms of its available V2G power (AVP) and flexible intervals are identified. The flexible interval is calculated using a powerful stochastic global optimization technique so-called “Free Pattern Search” (FPS). A probabilistic method is also proposed to quantify the impacts of PEV’s availability uncertainty using the Gaussian mixture model (GMM), and interdependency of stochastic variables on AVP of each fleet thanks to a multivariate modeling with Copula function. Each fleet is analyzed based on its aggregated PEV numbers at different level of distribution grid, in order to satisfy the ancillary services localization limitation. A case study using the proposed approach evaluates the real potential in Niort, a city in west of France. In fact, by using the proposed approach an aggregator can analyze the V2G potential of PEVs under its contract.

  20. Limitations to soybean photosynthesis at elevated carbon dioxide in free-air enrichment and open top chamber systems.

    Science.gov (United States)

    Bunce, James A

    2014-09-01

    It has been suggested that the stimulation of soybean photosynthesis by elevated CO2 was less in free-air carbon dioxide enrichment (FACE) systems than in open top chambers (OTC), which might explain smaller yield increases at elevated CO2 in FACE systems. However, this has not been tested using the same cultivars grown in the same location. I tested whether soybean photosynthesis at high light and elevated CO2 (ambient+180 μmol mol(-1)) was limited by electron transport (J) in FACE systems but by ribulose-bisphosphate carboxylation capacity (VCmax) in OTC. FACE systems with daytime and continuous CO2 enrichment were also compared. The results indicated that in both cultivars examined, midday photosynthesis at high light was always limited by VCmax, both in the FACE and in the OTC systems. Daytime only CO2 enrichment did not affect photosynthetic parameters or limitations, but did result in significantly smaller yields in both cultivars than continuous elevation. Photosynthesis measured at low photosynthetic photon flux density (PPFD) was not higher at elevated than at ambient CO2, because of an acclimation to elevated CO2 which was only evident at low measurement PPFDs. Published by Elsevier Ireland Ltd.

  1. Use of activated carbon as a support medium for H{sub 2}S biofiltration and effect of bacterial immobilization on available pore surface

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Y.L.; Yan, R.; Chen, X.G.; Geng, A.L.; Liang, D.T.; Koe, L.C.C. [Institute of Environmental Science and Engineering, Nanyang Technological Univ., Singapore (Singapore); Gould, W.D. [Environmental Lab., CANMET, Natural Resources Canada, Ottawa, ON (Canada)

    2004-12-01

    The use of support media for the immobilization of micro-organisms widely known to provide a surface for microbial growth and a shelter that protects the microorganisms from inhibitory compounds. In this study, activated carbon is used as a support medium for the immobilization of microorganisms enriched from municipal sewage activated sludge to remove gas-phase hydrogen sulfide (H{sub 2}S), a major odorous component of waste gas from sewage treatment plants. A series of designed experiments is used to examine the effect on bacteria-immobilized activated carbon (termed ''biocarbon'') due to physical adsorption, chemical reaction and microbial degradation in the overall removal of H{sub 2}S. H{sub 2}S breakthrough tests are conducted with various samples, including micro-immobilized carbon and Teflon discs, salts-medium-washed carbon, and ultra-pure water-washed carbon. The results show a higher removal capacity for the microbe-immobilized activated carbon compared with the activated carbon control in a batch biofilter column. The increase in removal capacity is attributed to the role played by the immobilized micro-organisms in metabolizing adsorbed sulfur and sulfur compounds on the biocarbon, hence releasing the adsorption sites for further H{sub 2}S uptake. The advantage for activated carbon serving as the support medium is to adsorb a high initial concentration of substrate and progressively release this for microbial degradation, hence acting as a buffer for the microorganisms. Results obtained from surface area and pore size distribution analyses of the biocarbon show a correlation between the available surface area and pore volume with the extent of microbial immobilization and H{sub 2}S uptake. The depletion of surface area and pore volume is seen as one of the factors which cause the onset of column breakthrough. Microbial growth retardation is due to the accumulation of metabolic products (i.e., sulfuric acid); and a lack of water and

  2. Potentials, consequences and trade-offs of terrestrial carbon dioxide removal. Strategies for climate engineering and their limitations

    Energy Technology Data Exchange (ETDEWEB)

    Boysen, Lena R.

    2017-01-17

    For hundreds of years, humans have engineered the planet to fulfil their need for increasing energy consumption and production. Since the industrial revolution, one consequence are rising global mean temperatures which could change by 2 C to 4.5 C until 2100 if mitigation enforcement of CO{sub 2} emissions fails.To counteract this projected global warming, climate engineering techniques aim at intendedly cooling Earth's climate for example through terrestrial carbon dioxide removal (tCDR) which is commonly perceived as environmentally friendly. Here, tCDR refers to the establishment of large-scale biomass plantations (BPs) in combination with the production of long-lasting carbon products such as bioenergy with carbon capture and storage or biochar. This thesis examines the potentials and possible consequences of tCDR by analysing land-use scenarios with different spatial and temporal scales of BPs using an advanced biosphere model forced by varying climate projections. These scenario simulations were evaluated with focus on their carbon sequestration potentials, trade-offs with food production and impacts on natural ecosystems and climate itself. Synthesised, the potential of tCDR to permanently extract CO{sub 2} out of the atmosphere is found to be small, regardless of the emission scenario, the point of onset or the spatial extent. On the contrary, the aforementioned trade-offs and impacts are shown to be unfavourable in most cases. In a high emission scenario with a late onset of BPs (i.e. around 2050), even unlimited area availability for tCDR could not reverse past emissions sufficiently, e.g. BPs covering 25% of all agricultural or natural land could delay 2100's carbon budget by no more than two or three decades (equivalent to ∼550 or 800 GtC tCDR), respectively. However, simultaneous emission reductions and an earlier establishment of BPs (i.e. around 2035) could result in strong carbon extractions reversing past emissions (e.g. six or eight

  3. Potentials, consequences and trade-offs of terrestrial carbon dioxide removal. Strategies for climate engineering and their limitations

    International Nuclear Information System (INIS)

    Boysen, Lena R.

    2017-01-01

    For hundreds of years, humans have engineered the planet to fulfil their need for increasing energy consumption and production. Since the industrial revolution, one consequence are rising global mean temperatures which could change by 2 C to 4.5 C until 2100 if mitigation enforcement of CO_2 emissions fails.To counteract this projected global warming, climate engineering techniques aim at intendedly cooling Earth's climate for example through terrestrial carbon dioxide removal (tCDR) which is commonly perceived as environmentally friendly. Here, tCDR refers to the establishment of large-scale biomass plantations (BPs) in combination with the production of long-lasting carbon products such as bioenergy with carbon capture and storage or biochar. This thesis examines the potentials and possible consequences of tCDR by analysing land-use scenarios with different spatial and temporal scales of BPs using an advanced biosphere model forced by varying climate projections. These scenario simulations were evaluated with focus on their carbon sequestration potentials, trade-offs with food production and impacts on natural ecosystems and climate itself. Synthesised, the potential of tCDR to permanently extract CO_2 out of the atmosphere is found to be small, regardless of the emission scenario, the point of onset or the spatial extent. On the contrary, the aforementioned trade-offs and impacts are shown to be unfavourable in most cases. In a high emission scenario with a late onset of BPs (i.e. around 2050), even unlimited area availability for tCDR could not reverse past emissions sufficiently, e.g. BPs covering 25% of all agricultural or natural land could delay 2100's carbon budget by no more than two or three decades (equivalent to ∼550 or 800 GtC tCDR), respectively. However, simultaneous emission reductions and an earlier establishment of BPs (i.e. around 2035) could result in strong carbon extractions reversing past emissions (e.g. six or eight decades or ∼500 or

  4. Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon

    Science.gov (United States)

    Berner, L. T.; Law, B. E.

    2015-11-01

    Severe droughts occurred in the western United States during recent decades, and continued human greenhouse gas emissions are expected to exacerbate warming and drying in this region. We investigated the role of water availability in shaping forest carbon cycling and morphological traits in the eastern Cascade Mountains, Oregon, focusing on the transition from low-elevation, dry western juniper (Juniperus occidentalis) woodlands to higher-elevation, wetter ponderosa pine (Pinus ponderosa) and grand fir (Abies grandis) forests. We examined 12 sites in mature forests that spanned a 1300 mm yr-1 gradient in mean growing-year climate moisture index (CMIgy ), computed annually (1964 to 2013) as monthly precipitation minus reference evapotranspiration and summed October to September. Maximum leaf area, annual aboveground productivity, and aboveground live tree biomass increased with CMIgy (r2 = 0.67-0.88, P gy (r2 = 0.53, P gy and extensive insect outbreak. Traits of stress-tolerant juniper included short stature, high wood density for cavitation resistance, and high investment in water transport relative to leaf area. Species occupying wetter areas invested more resources in height growth in response to competition for light relative to investment in hydraulic architecture. Consequently, maximum tree height, leaf area : sapwood area ratio, and stem wood density were all correlated with CMIgy . The tight coupling of forest carbon cycling and species traits with water availability suggests that warmer and drier conditions projected for the 21st century could have significant biogeochemical, ecological, and social consequences in the Pacific Northwest.

  5. Nitrogen and carbon limitation of planktonic primary production and phytoplankton-bacterioplankton coupling in ponds on the McMurdo Ice Shelf, Antarctica

    DEFF Research Database (Denmark)

    Sorrell, B.K.; Hawes, I.; Safi, K.

    2013-01-01

    The nature of nutrient limitation and coupling of planktonic primary and secondary production were investigated in meltwater ponds of the Ross Ice Shelf, Antarctica, using regression tree analysis and multiple regression. Phytoplankton were primaril N-limited but inorganic carbon apparently co...

  6. Reviews and syntheses: An empirical spatiotemporal description of the global surface-atmosphere carbon fluxes: opportunities and data limitations

    Science.gov (United States)

    Zscheischler, Jakob; Mahecha, Miguel D.; Avitabile, Valerio; Calle, Leonardo; Carvalhais, Nuno; Ciais, Philippe; Gans, Fabian; Gruber, Nicolas; Hartmann, Jens; Herold, Martin; Ichii, Kazuhito; Jung, Martin; Landschützer, Peter; Laruelle, Goulven G.; Lauerwald, Ronny; Papale, Dario; Peylin, Philippe; Poulter, Benjamin; Ray, Deepak; Regnier, Pierre; Rödenbeck, Christian; Roman-Cuesta, Rosa M.; Schwalm, Christopher; Tramontana, Gianluca; Tyukavina, Alexandra; Valentini, Riccardo; van der Werf, Guido; West, Tristram O.; Wolf, Julie E.; Reichstein, Markus

    2017-08-01

    Understanding the global carbon (C) cycle is of crucial importance to map current and future climate dynamics relative to global environmental change. A full characterization of C cycling requires detailed information on spatiotemporal patterns of surface-atmosphere fluxes. However, relevant C cycle observations are highly variable in their coverage and reporting standards. Especially problematic is the lack of integration of the carbon dioxide (CO2) exchange of the ocean, inland freshwaters and the land surface with the atmosphere. Here we adopt a data-driven approach to synthesize a wide range of observation-based spatially explicit surface-atmosphere CO2 fluxes from 2001 to 2010, to identify the state of today's observational opportunities and data limitations. The considered fluxes include net exchange of open oceans, continental shelves, estuaries, rivers, and lakes, as well as CO2 fluxes related to net ecosystem productivity, fire emissions, loss of tropical aboveground C, harvested wood and crops, as well as fossil fuel and cement emissions. Spatially explicit CO2 fluxes are obtained through geostatistical and/or remote-sensing-based upscaling, thereby minimizing biophysical or biogeochemical assumptions encoded in process-based models. We estimate a bottom-up net C exchange (NCE) between the surface (land, ocean, and coastal areas) and the atmosphere. Though we provide also global estimates, the primary goal of this study is to identify key uncertainties and observational shortcomings that need to be prioritized in the expansion of in situ observatories. Uncertainties for NCE and its components are derived using resampling. In many regions, our NCE estimates agree well with independent estimates from other sources such as process-based models and atmospheric inversions. This holds for Europe (mean ± 1 SD: 0.8 ± 0.1 PgC yr-1, positive numbers are sources to the atmosphere), Russia (0.1 ± 0.4 PgC yr-1), East Asia (1.6 ± 0.3 PgC yr-1), South Asia (0.3 ± 0

  7. Variation in soil moisture and N availability modulates carbon and water exchange in a California grassland experiment

    Energy Technology Data Exchange (ETDEWEB)

    St. Clair, S.B.; Sudderth, E.; Fischer, M.L.; Torn, M.S.; Stuart, S.; Salve, R.; Eggett, D.; Ackerly, D.

    2009-03-15

    Variability in the magnitude and timing of precipitation is predicted to change under future climate scenarios. The primary objective of this study was to understand how variation in precipitation patterns consisting of soil moisture pulses mixed with intermittent dry down events influence ecosystem gas fluxes. We characterized the effects of precipitation amount and timing, N availability, and plant community composition on whole ecosystem and leaf gas exchange in a California annual grassland mesocosm study system that allowed precise control of soil moisture conditions. Ecosystem CO2 and fluxes increased significantly with greater precipitation and were positively correlated with soil moisture. A repeated 10 day dry down period following 11 days of variable precipitation inputs strongly depressed net ecosystem CO2 exchange (NEE) across a range of season precipitation totals, and plant community types. Ecosystem respiration (Re), evapotranspiration (ET) and leaf level photosynthesis (Amax) showed greatest sensitivity to dry down periods in low precipitation plots. Nitrogen additions significantly increased NEE, Re and Amax, particularly as water availability was increased. These results demonstrate that N availability and intermittent periods of soil moisture deficit (across a wide range of cumulative season precipitation totals) strongly modulate ecosystem gas exchange.

  8. Influence of CH4 and H2S availability on symbiont distribution, carbon assimilation and transfer in the dual symbiotic vent mussel Bathymodiolus azoricus

    Directory of Open Access Journals (Sweden)

    R. S. Santos

    2008-12-01

    Full Text Available High densities of mussels of the genus Bathymodiolus are present at hydrothermal vents of the Mid-Atlantic Ridge. It was previously proposed that the chemistry at vent sites would affect their sulphide- and methane-oxidizing endosymbionts' abundance. In this study, we confirmed the latter assumption using fluorescence in situ hybridization on Bathymodiolus azoricus specimens maintained in a controlled laboratory environment at atmospheric pressure with one, both or none of the chemical substrates. A high level of symbiosis plasticity was observed, methane-oxidizers occupying between 4 and 39% of total bacterial area and both symbionts developing according to the presence or absence of their substrates. Using H13CO3− in the presence of sulphide, or 13CH4, we monitored carbon assimilation by the endosymbionts and its translocation to symbiont-free mussel tissues. Carbon was incorporated from methane and sulphide-oxidized inorganic carbon at rates 3 to 10 times slower in the host muscle tissue than in the symbiont-containing gill tissue. Both symbionts thus contribute actively to B. azoricus nutrition and adapt to the availability of their substrates. Further experiments with varying substrate concentrations using the same set-up should provide useful tools to study and even model the effects of changes in hydrothermal fluids on B. azoricus' chemosynthetic nutrition.

  9. Characterization of phosphofructokinase activity in Mycobacterium tuberculosis reveals that a functional glycolytic carbon flow is necessary to limit the accumulation of toxic metabolic intermediates under hypoxia.

    Directory of Open Access Journals (Sweden)

    Wai Yee Phong

    Full Text Available Metabolic versatility has been increasingly recognized as a major virulence mechanism that enables Mycobacterium tuberculosis to persist in many microenvironments encountered in its host. Glucose is one of the most abundant carbon sources that is exploited by many pathogenic bacteria in the human host. M. tuberculosis has an intact glycolytic pathway that is highly conserved in all clinical isolates sequenced to date suggesting that glucose may represent a non-negligible source of carbon and energy for this pathogen in vivo. Fructose-6-phosphate phosphorylation represents the key-committing step in glycolysis and is catalyzed by a phosphofructokinase (PFK activity. Two genes, pfkA and pfkB have been annotated to encode putative PFK in M. tuberculosis. Here, we show that PFKA is the sole PFK enzyme in M. tuberculosis with no functional redundancy with PFKB. PFKA is required for growth on glucose as sole carbon source. In co-metabolism experiments, we report that disruption of the glycolytic pathway at the PFK step results in intracellular accumulation of sugar-phosphates that correlated with significant impairment of the cell viability. Concomitantly, we found that the presence of glucose is highly toxic for the long-term survival of hypoxic non-replicating mycobacteria, suggesting that accumulation of glucose-derived toxic metabolites does occur in the absence of sustained aerobic respiration. The culture medium traditionally used to study the physiology of hypoxic mycobacteria is supplemented with glucose. In this medium, M. tuberculosis can survive for only 7-10 days in a true non-replicating state before death is observed. By omitting glucose in the medium this period could be extended for up to at least 40 days without significant viability loss. Therefore, our study suggests that glycolysis leads to accumulation of glucose-derived toxic metabolites that limits long-term survival of hypoxic mycobacteria. Such toxic effect is exacerbated when

  10. Effect of Phytase Superdoses and Citric Acid on Growth Performance, Plasma Phosphorus and Tibia Ash in Broilers Fed Canola Meal-Based Diets Severely Limited in Available Phosphorus

    Directory of Open Access Journals (Sweden)

    Taheri HR

    2015-06-01

    Full Text Available This experiment was conducted to investigate the effect of phytase superdoses alone or in combination with citric acid (CA in canola meal-based diets severely limited in available phosphorus (Pa on growth performance, plasma phosphorus (P, and tibia ash (TA in broilers from 22 to 42 d of age. Two hundreds and eighty 21-d-old male broilers were used in 28 pens of 10 birds per each. The experimental diets consisted of a positive control (PC diet and six negative control (NC diets which consisted of two levels of CA (0 and 20 g/Kg and three levels of phytase (0, 1000 and 4000 U/Kg in a 2 × 3 factorial arrangement. The PC diet contained 4.3 g/Kg Pa, but all NC diets contained 1.5 g/Kg Pa. Results indicated that the birds fed the PC diet had a significantly higher average daily gain (ADG, plasma P and TA, but a lower feed conversion ratio (FCR than those fed the NC diet. The ADG, FCR and plasma P values in birds fed NC diets supplemented with 4000 U/Kg phytase enzyme (with or without CA significantly reached those of birds fed the PC diet. But, addition of phytase enzyme at 1000 U/Kg only plus CA to the NC diet could significantly improve FCR and plasma P. A significant interaction was observed between phytase and CA for FCR and plasma P. Although TA values in NC + 1000 U/Kg phytase treatments (with or without CA were similar to the PC treatment, TA values of NC + 4000 U/Kg phytase treatments (with or without CA was greater than that of the PC treatment. Results of this study showed that, in severely limited Pa corn-canola meal-based diets, supplementing 4000 U/Kg phytase or also 1000 U/Kg phytase plus CA will be sufficient to obtain the comparable feed efficiency in broilers to those fed the adequate Pa diet.

  11. Nutrient amendment does not increase mineralisation of sequestered carbon during incubation of a nitrogen limited mangrove soil

    KAUST Repository

    Keuskamp, Joost A.; Schmitt, Heike; Laanbroek, Hendrikus J.; Verhoeven, Jos T.A.; Hefting, Mariet M.

    2013-01-01

    Mangrove forests are sites of intense carbon and nutrient cycling, which result in soil carbon sequestration on a global scale. Currently, mangrove forests receive increasing quantities of exogenous nutrients due to coastal development. The present

  12. Limitations of using Raman microscopy for the analysis of high-content-carbon-filled ethylene propylene diene monomer rubber

    DEFF Research Database (Denmark)

    Ghanbari-Siahkali, A.; Almdal, K.; Kingshott, P.

    2003-01-01

    The effects of laser irradiation on changes to the surface chemistry and structure of a commercially available ethylene propylene diene monomer (EPDM) rubber sample after Raman microscopy analysis was investigated. The Raman measurements were carried out with different levels of laser power...... on the sample, ranging from 4.55 mW to 0.09 mW. The surface of the EPDM was analyzed before and after laser exposure using X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The techniques have surface probe depths of approximately less...... than or equal to10 nm and 1 mum, respectively. Both sets of analysis show that ingredients of the blended EPDM rubber "bloom" to the surface as a result of local heating that takes place due to the absorption of laser by carbon black during the Raman analysis. Scanning electron microscopy (SEM...

  13. Metabolic Availability of the Limiting Amino Acids Lysine and Tryptophan in Cooked White African Cornmeal Assessed in Healthy Young Men Using the Indicator Amino Acid Oxidation Technique.

    Science.gov (United States)

    Rafii, Mahroukh; Elango, Rajavel; Ball, Ronald O; Pencharz, Paul B; Courtney-Martin, Glenda

    2018-06-01

    Maize is a staple food in many regions of the world, particularly in Africa and Latin America. However, maize protein is limiting in the indispensable amino acids lysine and tryptophan, making its protein of poor quality. The main objective of this study was to determine the protein quality of white African cornmeal by determining the metabolic availability (MA) of lysine and tryptophan. To determine the MA of lysine, 4 amounts of l-lysine (10, 13, 16, and 18 mg · kg-1 · d-1 totaling 28.6%, 37.1%, 45.7%, and 51.4% of the mean lysine requirement of 35 mg · kg-1 · d-1, respectively) were studied in 6 healthy young men in a repeated-measures design. To determine the MA of tryptophan, 4 amounts of l-tryptophan (0.5, 1, 1.5, and 2 mg · kg-1 · d-1 totaling 12.5%, 25.0%, 37.5%, and 50.0% of the mean tryptophan requirement of 4 mg · kg-1 · d-1, respectively) were studied in 7 healthy young men in a repeated-measures design. The MAs of lysine and tryptophan were estimated by comparing the indicator amino acid oxidation (IAAO) response with varying intakes of lysine and tryptophan in cooked white cornmeal compared with the IAAO response to l-lysine and l-tryptophan intakes in the reference protein (crystalline amino acid mixture patterned after egg protein) with the use of the slope ratio method. The MAs of lysine and tryptophan from African cooked white cornmeal were 71% and 80%, respectively. Our study provides a robust estimate of the availability of lysine and tryptophan in African white maize to healthy young men. This estimate provides a basis for postproduction fortification or supplementation of maize-based diets. This trial was registered at www.clinicaltrials.gov as NCT02402179.

  14. Denitrification on internal carbon sources in RAS is limited by fibers in fecal waste of rainbow trout

    NARCIS (Netherlands)

    Meriac, A.; Eding, E.H.; Kamstra, A.; Busscher, J.P.; Schrama, J.W.; Verreth, J.A.J.

    2014-01-01

    Denitrification on internal carbon sources offers the advantage to control nitrate levels in recirculating aquaculture systems (RAS) by using the fecal carbon produced within the husbandry system. However, it is not clear to which extent fecal carbon can be utilized by the microbial community within

  15. Nitrogen and carbon limitation of planktonic primary production and phytoplankton–bacterioplankton coupling in ponds on the McMurdo Ice Shelf, Antarctica

    International Nuclear Information System (INIS)

    Sorrell, Brian K; Safi, Karl; Hawes, Ian

    2013-01-01

    We compared planktonic primary and secondary production across twenty meltwater ponds on the surface of the McMurdo Ice Shelf in January 2007, including some ponds with basal brines created by meromictic stratification. Primary production ranged from 1.07 to 65.72 mgC m −3 h −1 in surface waters. In stratified ponds primary production was always more than ten times higher in basal brines than in the corresponding mixolimnion. Regression tree analysis (r 2 = 0.80) identified inorganic nitrogen (as NH 4 + ) as the main factor limiting planktonic primary production. However, there was also evidence of inorganic carbon co-limitation of photosynthesis in some of the more oligotrophic waters. Neither C nor N limited carbon fixation at [NH 4 –N] > 50 mg m −3 , with photoinhibition the factor most likely limiting photosynthesis under such conditions. Primary production was the only factor significantly correlated to bacterial production and the relationship (r 2 = 0.56) was non-linear. Nitrogen limitation and tight coupling of planktonic primary and bacterial production is surprising in these ponds, as all have large pools of dissolved organic carbon (1.2–260 g m −3 ) and organic nitrogen (all >130 mg m −3 ). The dissolved pools of organic carbon and nitrogen appear to be recalcitrant and bacterial production to be constrained by limited release of labile organics from phytoplankton. (letter)

  16. Effects of High Dissolved Inorganic and Organic Carbon Availability on the Physiology of the Hard Coral Acropora millepora from the Great Barrier Reef.

    Directory of Open Access Journals (Sweden)

    Friedrich W Meyer

    Full Text Available Coral reefs are facing major global and local threats due to climate change-induced increases in dissolved inorganic carbon (DIC and because of land-derived increases in organic and inorganic nutrients. Recent research revealed that high availability of labile dissolved organic carbon (DOC negatively affects scleractinian corals. Studies on the interplay of these factors, however, are lacking, but urgently needed to understand coral reef functioning under present and near future conditions. This experimental study investigated the individual and combined effects of ambient and high DIC (pCO2 403 μatm/ pHTotal 8.2 and 996 μatm/pHTotal 7.8 and DOC (added as Glucose 0 and 294 μmol L-1, background DOC concentration of 83 μmol L-1 availability on the physiology (net and gross photosynthesis, respiration, dark and light calcification, and growth of the scleractinian coral Acropora millepora (Ehrenberg, 1834 from the Great Barrier Reef over a 16 day interval. High DIC availability did not affect photosynthesis, respiration and light calcification, but significantly reduced dark calcification and growth by 50 and 23%, respectively. High DOC availability reduced net and gross photosynthesis by 51% and 39%, respectively, but did not affect respiration. DOC addition did not influence calcification, but significantly increased growth by 42%. Combination of high DIC and high DOC availability did not affect photosynthesis, light calcification, respiration or growth, but significantly decreased dark calcification when compared to both controls and DIC treatments. On the ecosystem level, high DIC concentrations may lead to reduced accretion and growth of reefs dominated by Acropora that under elevated DOC concentrations will likely exhibit reduced primary production rates, ultimately leading to loss of hard substrate and reef erosion. It is therefore important to consider the potential impacts of elevated DOC and DIC simultaneously to assess real world

  17. Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current

    Science.gov (United States)

    Assmy, Philipp; Smetacek, Victor; Montresor, Marina; Klaas, Christine; Henjes, Joachim; Strass, Volker H.; Arrieta, Jesús M.; Bathmann, Ulrich; Berg, Gry M.; Breitbarth, Eike; Cisewski, Boris; Friedrichs, Lars; Fuchs, Nike; Herndl, Gerhard J.; Jansen, Sandra; Krägefsky, Sören; Latasa, Mikel; Peeken, Ilka; Röttgers, Rüdiger; Scharek, Renate; Schüller, Susanne E.; Steigenberger, Sebastian; Webb, Adrian; Wolf-Gladrow, Dieter

    2013-01-01

    Diatoms of the iron-replete continental margins and North Atlantic are key exporters of organic carbon. In contrast, diatoms of the iron-limited Antarctic Circumpolar Current sequester silicon, but comparatively little carbon, in the underlying deep ocean and sediments. Because the Southern Ocean is the major hub of oceanic nutrient distribution, selective silicon sequestration there limits diatom blooms elsewhere and consequently the biotic carbon sequestration potential of the entire ocean. We investigated this paradox in an in situ iron fertilization experiment by comparing accumulation and sinking of diatom populations inside and outside the iron-fertilized patch over 5 wk. A bloom comprising various thin- and thick-shelled diatom species developed inside the patch despite the presence of large grazer populations. After the third week, most of the thinner-shelled diatom species underwent mass mortality, formed large, mucous aggregates, and sank out en masse (carbon sinkers). In contrast, thicker-shelled species, in particular Fragilariopsis kerguelensis, persisted in the surface layers, sank mainly empty shells continuously, and reduced silicate concentrations to similar levels both inside and outside the patch (silica sinkers). These patterns imply that thick-shelled, hence grazer-protected, diatom species evolved in response to heavy copepod grazing pressure in the presence of an abundant silicate supply. The ecology of these silica-sinking species decouples silicon and carbon cycles in the iron-limited Southern Ocean, whereas carbon-sinking species, when stimulated by iron fertilization, export more carbon per silicon. Our results suggest that large-scale iron fertilization of the silicate-rich Southern Ocean will not change silicon sequestration but will add carbon to the sinking silica flux. PMID:24248337

  18. Studies of HVC Plasticity in Adult Canaries Reveal Social Effects and Sex Differences as Well as Limitations of Multiple Markers Available to Assess Adult Neurogenesis.

    Directory of Open Access Journals (Sweden)

    Olesya T Shevchouk

    Full Text Available In songbirds, neurogenesis in the song control nucleus HVC is sensitive to the hormonal and social environment but the dynamics of this process is difficult to assess with a single exogenous marker of new neurons. We simultaneously used three independent markers to investigate HVC neurogenesis in male and female canaries. Males were castrated, implanted with testosterone and housed either alone (M, with a female (M-F or with another male (M-M while females were implanted with 17β-estradiol and housed with a male (F-M. All subjects received injections of the two thymidine analogues, BrdU and of EdU, respectively 21 and 10 days before brain collection. Cells containing BrdU or EdU or expressing doublecortin (DCX, which labels newborn neurons, were quantified. Social context and sex differentially affected total BrdU+, EdU+, BrdU+EdU- and DCX+ populations. M-M males had a higher density of BrdU+ cells in the ventricular zone adjacent to HVC and of EdU+ in HVC than M-F males. M birds had a higher ratio of BrdU+EdU- to EdU+ cells than M-F subjects suggesting higher survival of newer neurons in the former group. Total number of HVC DCX+ cells was lower in M-F than in M-M males. Sex differences were also dependent of the type of marker used. Several technical limitations associated with the use of these multiple markers were also identified. These results indicate that proliferation, recruitment and survival of new neurons can be independently affected by environmental conditions and effects can only be fully discerned through the use of multiple neurogenesis markers.

  19. Effect of high-dose phytase supplementation in broilers from 22 to 42 days post-hatch given diets severely limited in available phosphorus.

    Science.gov (United States)

    Taheri, H R; Heidari, A; Shahir, M H

    2015-01-01

    1. Two trials were conducted from 22 to 42 d post-hatch to evaluate the effectiveness of high concentrations of supplemental phytase in maize-soya bean meal-based diets severely limited in available phosphorus (P). Growth performance, plasma P and tibia ash (TA) were measured. 2. Each trial used 220 21-d-old male broilers in 20 pens with 11 birds per pen. Dietary treatments included a positive control [PC, 4.3 g/kg nonphytate P (NPP)], negative control [NC, 2.3 g/kg NPP (Trial 1) or 1.4 g/kg NPP (Trial 2)] and NC plus 1000, 2000 or 4000 phytase U/kg of the diet. 3. Birds fed on the PC diet had higher average daily gain (ADG), gain to feed ratio (G:F), plasma P (Trials 1 and 2) and TA (Trial 2) than those fed on the NC. 4. In Trial 1, ADG and G:F values of the NC plus 1000, 2000 or 4000 phytase U/kg reached those of the PC. Plasma P values of the NC plus 2000 or 4000 phytase U/kg reached that of the PC. Although TA values of the NC, NC + 1000 or NC + 2000 reached that of the PC, TA of the NC + 4000 was more than that of the PC. 5. In Trial 2, ADG and G:F values of the NC plus 4000 phytase U/kg reached those of the PC; nevertheless, plasma P values of the NC diets did not come up to that of the PC. While TA values of the NC, NC + 1000 or NC + 2000 did not reach that of the PC, TA of the NC + 4000 was greater than that of the PC. 6. Results of this study showed that, in the diets with 2.3 and 1.4 g/kg NPP, respectively, 1000 and 4000 phytase U/kg can be sufficient to obtain a comparable performance in broilers to those given diets adequate in available P.

  20. Diagnostic Evaluation of Carbon Sources in CMAQ

    Science.gov (United States)

    Traditional monitoring networks measure only total elemental carbon (EC) and organic carbon (OC) routinely. Diagnosing model biases with such limited information is difficult. Measurements of organic tracer compounds have recently become available and allow for more detailed di...

  1. Chemical oxygen demand removal efficiency and limited factors study of aminosilicone polymers in a water emulsion by iron-carbon micro-electrolysis.

    Science.gov (United States)

    Yang, Shangyuan; Liang, Zhiwei; Yu, Huadong; Wang, Yunlong; Chen, Yingxu

    2014-02-01

    Micro-electrolysis was applied in the present study to investigate the effect of pH, iron-carbon mass ratio, contact time, and treatment batch on the removal efficiency of chemical oxygen demand (COD) within an aminosilicone emulsion. The results exhibited that the removal efficiency of COD decreased linearly with the batch increase, and this tendency was consistent under the various conditions. The adsorption of activated carbons contributes a large portion to the elimination of COD within the aminosilicone emulsion. The oxidation action of iron-carbon micro-electrolysis was proven and the aminosilicone emulsion's COD removal contribution was approximately 16%. Aminosilicone polymers were adsorbed on the surface of activated carbons and iron chips, which contributes to the decline of COD removal efficiency and limits the contribution of oxidation action.

  2. The C-household of young broad-leaved and conifer tree species exposed to long-term carbon limitation by shading

    Science.gov (United States)

    Weber, Raphael; Hoch, Günter

    2017-04-01

    Non-structural carbohydrates (NSC, i.e. free sugars and starch) are regarded as freely available carbon (C) reserves in plants. They are often quantified to estimate a plant's C-balance, assuming that NSC are controlled by the net-balance between photo-assimilation and C-usage (respiration, growth and other sinks). Within a recent field experiment, we investigated the extent, to which C-reserves (NSC) can be formed in young trees against prevailing C-sink demands (growth) under C-limitation. A total of almost 1000 individuals of two-year-old tree saplings from 6 deciduous, broadleaved species and 4 evergreen conifer species were planted on a field side. Half of the trees per species were treated with long-term C-limitation by exposing them to continuous deep shade conditions (5% of natural PPFD) under a permanent shading tent. C gas-exchange, growth and NSC tissue concentrations were analyzed in shaded and unshaded saplings for two consecutive years. Three months after the beginning of the experiment, leaf photosynthesis acclimatized to the low light conditions, with leaves of shaded trees showing significantly higher SLA and lower light saturation and maximum photosynthesis. During the second season of the experiment, most species exhibited very strong reductions in NSC, but much less pronounced reductions in growth. In contrast, other species, with few exceptions, kept NSC concentrations similar to unshaded controls, while growth virtually stopped under deep shade. In conclusion, we found species-specific strategies in the trees' C-household after two years of C-limitation, that fall into two major carbon allocation strategies: 1) "C-spenders", which deplete C reserves in order to keep up significant growth, and 2) "C-savers", which reduce C sink activities to a minimum in order to store substantial amounts of C reserves. Overall, early-successional species tended to follow the first strategy, while late-successional species tended to save higher C reserve pools

  3. The limits of evidence in drug approval and availability: a case study of cilostazol and naftidrofuryl for the treatment of intermittent claudication.

    Science.gov (United States)

    Hong, Haeyeon; Mackey, William C

    2014-08-01

    Despite numerous efforts to develop effective medications for the treatment of intermittent claudication (IC) over the past 4 decades, a gold standard medical management option has yet to be defined. Although not life-threatening, IC interferes with mobility and activities of daily living, significantly impairing quality of life and potentially causing depression. Cilostazol, the leading pharmacologic agent for IC in the United States, was approved by the US Food and Drug Administration (FDA) in 1999 based on controversial data. Meanwhile, naftidrofuryl, the first-line pharmacologic agent for IC in the United Kingdom and Europe, has never been approved by the FDA and therefore is not available in the United States. The clinical data for cilostazol and naftidrofuryl are plagued by flaws related to lack of protocol standardization, objective endpoints, and strict eligibility criteria in study subjects, making identification of a true treatment effect impossible. Furthermore, no prospective randomized trial comparing the efficacy of cilostazol and naftidrofuryl has been conducted, because the manufacturers of these agents have much to lose and little to gain from such a study. This article provides an overview of the pharmacology of cilostazol and naftidrofuryl, and the clinical studies leading to their approval and clinical acceptance. It further explores the possible sources of bias in analyzing these clinical trials, some of which have been brought to light by the National Institute for Health and Clinical Excellence (NICE) of the United Kingdom in its technology appraisal guidance. It also speculates the ways in which economic incentives may affect drug-marketing decisions. A literature review of pharmacology and clinical trials for cilostazol and naftidrofuryl was performed in PubMed. The majority of included clinical trials were initially identified through the most recent Cochrane review articles as well as the FDA's approval packet for cilostazol. The

  4. Effect of high-dose phytase and citric acid, alone or in combination, on growth performance of broilers given diets severely limited in available phosphorus.

    Science.gov (United States)

    Taheri, H R; Jabbari, Z; Adibnia, S; Shahir, M H; Hosseini, S A

    2015-01-01

    1. Two trials were conducted to evaluate the effect of high-dose phytase alone or in combination with citric acid (CA) in the diet severely limited in available phosphorus (P) on performance, plasma P and plasma Ca of broilers from 22 to 42 d of age. 2. In Trial 1, 297 21-d-old female chicks were placed into 27 pens and allocated to 9 maize-soybean meal-based dietary treatments, which were a positive control [PC, 4.23 g/kg non-phytate P (NPP)] and 8 negative control (NC, 1.35 g/kg NPP) groups consisting of two concentrations of CA (0 and 20 g/kg) and 4 concentrations of phytase (0, 1000, 2000 and 4000 U/kg) in a 2 × 4 factorial arrangement. In Trial 2, 192 21-d-old male chicks were placed into 24 pens and allocated to 6 wheat-canola meal-based dietary treatments, which were a PC (4.2 g/kg NPP), a NC (1.68 g/kg NPP) and 4 NC groups consisting of two concentrations of CA (0 and 20 g/kg) and two concentrations of phytase (2000 and 4000 U/kg) in a 2 × 2 factorial arrangement. 3. In both trials, birds fed on the PC had significantly higher average daily gain (ADG), average daily feed intake (ADFI), plasma P and lower feed conversion ratio (FCR) and plasma Ca than those of birds fed on the NC. CA supplementation significantly increased ADG and ADFI. There was a significant interaction between CA and phytase on plasma P where CA improved the effect of phytase on plasma P. In Trial 1, phytase addition improved ADG, ADFI, FCR and plasma Ca linearly. 4. Briefly, this research showed the interaction effect between CA and phytase on plasma P when broilers were fed on diets based on maize-soybean meal or wheat-canola meal. The results showed that CA supplementation lowered the concentration of phytase that is needed in low NPP diets to increase plasma P.

  5. Competition of a parathion-hydrolyzing Flavobacterium with bacteria from ditch water in carbon-, nitrate- and phosphate-limited continuous cultures

    NARCIS (Netherlands)

    Sprenger, W.; Dijkstra, A.; Zwart, G.; Van Agterveld, M.P.; Van Noort, P.C.M.; Parsons, J.R.

    2003-01-01

    The effect of competition for macroelements with bacteria from ditch water on the parathion-hydrolyzing Flavobacterium sp. ATCC 27551 (FB) was investigated within mixed continuous cultures under carbon-, nitrate- or phosphate-limited conditions. The high initial rate of parathion hydrolysis

  6. Climate Change and Future U.S. Electricity Infrastructure: the Nexus between Water Availability, Land Suitability, and Low-Carbon Technologies

    Science.gov (United States)

    Rice, J.; Halter, T.; Hejazi, M. I.; Jensen, E.; Liu, L.; Olson, J.; Patel, P.; Vernon, C. R.; Voisin, N.; Zuljevic, N.

    2014-12-01

    Integrated assessment models project the future electricity generation mix under different policy, technology, and socioeconomic scenarios, but they do not directly address site-specific factors such as interconnection costs, population density, land use restrictions, air quality, NIMBY concerns, or water availability that might affect the feasibility of achieving the technology mix. Moreover, since these factors can change over time due to climate, policy, socioeconomics, and so on, it is important to examine the dynamic feasibility of integrated assessment scenarios "on the ground." This paper explores insights from coupling an integrated assessment model (GCAM-USA) with a geospatial power plant siting model (the Capacity Expansion Regional Feasibility model, CERF) within a larger multi-model framework that includes regional climate, hydrologic, and water management modeling. GCAM-USA is a dynamic-recursive market equilibrium model simulating the impact of carbon policies on global and national markets for energy commodities and other goods; one of its outputs is the electricity generation mix and expansion at the state-level. It also simulates water demands from all sectors that are downscaled as input to the water management modeling. CERF simulates siting decisions by dynamically representing suitable areas for different generation technologies with geospatial analyses (informed by technology-specific siting criteria, such as required mean streamflow per the Clean Water Act), and then choosing siting locations to minimize interconnection costs (to electric transmission and gas pipelines). CERF results are compared across three scenarios simulated by GCAM-USA: 1) a non-mitigation scenario (RCP8.5) in which conventional fossil-fueled technologies prevail, 2) a mitigation scenario (RCP4.5) in which the carbon price causes a shift toward nuclear, carbon capture and sequestration (CCS), and renewables, and 3) a repeat of scenario (2) in which CCS technologies are

  7. 75 FR 1335 - Circular Welded Carbon Steel Pipes and Tubes from Taiwan; Extension of Time Limit for Preliminary...

    Science.gov (United States)

    2010-01-11

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-583-008] Circular Welded Carbon Steel... review of the antidumping duty order on circular welded carbon steel pipes and tubes from Taiwan.\\1\\ On... review within the original time frame because we require additional time to obtain information from the...

  8. Irrigation management and phosphorus addition alter the abundance of carbon dioxide-fixing autotrophs in phosphorus-limited paddy soil.

    Science.gov (United States)

    Wu, Xiaohong; Ge, Tida; Yan, Wende; Zhou, Juan; Wei, Xiaomeng; Chen, Liang; Chen, Xiangbi; Nannipieri, Paolo; Wu, Jinshui

    2017-12-01

    In this study, we assessed the interactive effects of phosphorus (P) application and irrigation methods on the abundances of marker genes (cbbL, cbbM, accA and aclB) of CO2-fixing autotrophs. We conducted rice-microcosm experiments using a P-limited paddy soil, with and without the addition of P fertiliser (P-treated-pot (P) versus control pot (CK)), and using two irrigation methods, namely alternate wetting and drying (AWD) and continuous flooding (CF). The abundances of bacterial 16S rRNA, archaeal 16S rRNA, cbbL, cbbM, accA and aclB genes in the rhizosphere soil (RS) and bulk soil (BS) were quantified. The application of P significantly altered the soil properties and stimulated the abundances of Bacteria, Archaea and CO2-fixation genes under CF treatment, but negatively influenced the abundances of Bacteria and marker genes of CO2-fixing autotrophs in BS soils under AWD treatment. The response of CO2-fixing autotrophs to P fertiliser depended on the irrigation management method. The redundancy analysis revealed that 54% of the variation in the functional marker gene abundances could be explained by the irrigation method, P fertiliser and the Olsen-P content; however, the rhizosphere effect did not have any significant influence. P fertiliser application under CF was more beneficial in improving the abundance of CO2-fixing autotrophs compared to the AWD treatment; thus, it is an ideal irrigation management method to increase soil carbon fixation. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Variation of Enzyme Activities and Metabolite Levels in 24 Arabidopsis Accessions Growing in Carbon-Limited Conditions1[W

    Science.gov (United States)

    Cross, Joanna M.; von Korff, Maria; Altmann, Thomas; Bartzetko, Linda; Sulpice, Ronan; Gibon, Yves; Palacios, Natalia; Stitt, Mark

    2006-01-01

    Our understanding of the interaction of carbon (C) metabolism with nitrogen (N) metabolism and growth is based mainly on studies of responses to environmental treatments, and studies of mutants and transformants. Here, we investigate which metabolic parameters vary and which parameters change in a coordinated manner in 24 genetically diverse Arabidopsis (Arabidopsis thaliana) accessions, grown in C-limited conditions. The accessions were grown in short days, moderate light, and high nitrate, and analyzed for rosette biomass, levels of structural components (protein, chlorophyll), total phenols and major metabolic intermediates (sugars, starch, nitrate, amino acids), and the activities of seven representative enzymes from central C and N metabolism. The largest variation was found for plant weight, reducing sugars, starch at the end of the night, and several enzyme activities. High levels of one sugar correlated with high levels of other sugars and starch, and a trend to increased amino acids, slightly lower nitrate, and higher protein. The activities of enzymes at the interface of C and N metabolism correlated with each other, but were unrelated to carbohydrates, amino acid levels, and total protein. Rosette weight was unrelated or showed a weak negative trend to sugar and amino acid contents at the end of the day in most of the accessions, and was negatively correlated with starch at the end of the night. Rosette weight was positively correlated with several enzyme activities. We propose that growth is not related to the absolute levels of starch, sugars, and amino acids; instead, it is related to flux, which is indicated by the enzymatic capacity to use these central resources. PMID:17085515

  10. Influence of limit-feeding and time of day of feed availability to growing calves on growth performance and feeding behavior in cold weather.

    Science.gov (United States)

    Prezotto, L D; Gilbery, T C; Bauer, M L; Islas, A; Swanson, K C

    2017-11-01

    Objective swere to determine the effects of limit-feeding and time of feed access in cold weather on growth performance and feeding behavior of growing calves fed a corn silage-based diet. Sixty-six steers (BW = 317 ± 5.3 kg) and 30 heifers (BW = 239 ± 7.6 kg) were assigned randomly to dietary treatment: 1) ad libitum feed intake (AL), 2) limit-fed to 80% of the average DMI of the AL group on a BW basis in the daytime (0601-1759 h; LF-D), 3) limit-fed to 80% of the average DMI of the AL group on a BW basis in the nighttime (1800-0559 h; LF-N), and 4) limit-fed to 80% of the average DMI of the AL group on a BW basis, split 1/2 in the daytime and 1/2 in the nighttime (LF-S). Feed intake and feeding behavior were monitored over 84 d using the Insentec feeding system. Average daily gain, DMI, and G:F were greater ( ≤ 0.002) in the AL group compared with others. Dry matter intake was not different ( = 0.17) when comparing the LF-D with the LF-N groups. Average daily gain and G:F were greater ( ≤ 0.05) when comparing the LF-N group to the LF-D group, and were not different ( ≥ 0.51) when comparing the LF-S group with the mean of the LF-D and LF-N groups. Number of visits and meals per d was greater ( ≤ 0.001) in the LF-N than the LF-D group. Feed intake per visit was not different ( = 0.55) when comparing the AL group and others, and tended to be greater ( = 0.06) in the LF-D than the LF-N group. Feed intake per meal was greater ( Feed intake per minute (eating rate) was not influenced by treatment. In conclusion, limit-feeding at 80% of ad libitum intake decreased ADG and G:F. Limit-feeding in the nighttime as compared to limit-feeding in the daytime improves growth performance and increases feeding activity (number of visits and meals per d) which could be because of increased heat production to help maintain body temperature and thus reduce maintenance energy requirements.

  11. Metabolic and transcriptomic response of the wine yeast Saccharomyces cerevisiae strain EC1118 after an oxygen impulse under carbon-sufficient, nitrogen-limited fermentative conditions.

    Science.gov (United States)

    Orellana, Marcelo; Aceituno, Felipe F; Slater, Alex W; Almonacid, Leonardo I; Melo, Francisco; Agosin, Eduardo

    2014-05-01

    During alcoholic fermentation, Saccharomyces cerevisiae is exposed to continuously changing environmental conditions, such as decreasing sugar and increasing ethanol concentrations. Oxygen, a critical nutrient to avoid stuck and sluggish fermentations, is only discretely available throughout the process after pump-over operation. In this work, we studied the physiological response of the wine yeast S. cerevisiae strain EC1118 to a sudden increase in dissolved oxygen, simulating pump-over operation. With this aim, an impulse of dissolved oxygen was added to carbon-sufficient, nitrogen-limited anaerobic continuous cultures. Results showed that genes related to mitochondrial respiration, ergosterol biosynthesis, and oxidative stress, among other metabolic pathways, were induced after the oxygen impulse. On the other hand, mannoprotein coding genes were repressed. The changes in the expression of these genes are coordinated responses that share common elements at the level of transcriptional regulation. Beneficial and detrimental effects of these physiological processes on wine quality highlight the dual role of oxygen in 'making or breaking wines'. These findings will facilitate the development of oxygen addition strategies to optimize yeast performance in industrial fermentations. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  12. Electro-deposition of Pd on Carbon paper and Ni foam via surface limited redox-replacement reaction for oxygen reduction reaction

    International Nuclear Information System (INIS)

    Modibedi, Remegia M.; Mathe, Mkhulu K.; Motsoeneng, Rapelang G.; Khotseng, Lindiwe E.; Ozoemena, Kenneth I.; Louw, Eldah K.

    2014-01-01

    Pd nanostructured catalysts were electrodeposited by surface-limited redox replacement reactions using the electrochemical atomic layer deposition technique. Carbon paper and Ni foam were used as substrates for the electrodeposition of the metal. Supported nanostructured Pd electrodes were characterized using electrochemical methods and scanning electron microscopy. Carbon paper and Ni foam produced good quality deposits with some agglomeration on Ni foam. The EDX profiles confirmed the presence of Pd particles. Cyclic voltammograms of the electrodeposited Pd on substrates showed features characteristic of polycrystalline Pd electrodes. In the acidic electrolyte a very weak oxygen reduction reaction (ORR) activity was observed on Pd/Carbon paper electrode when compared to Pd/Ni foam electrode. The Pd/Ni foam electrode showed improved ORR activity in alkaline medium

  13. Correlation of stable elevations in striatal mu-opioid receptor availability in detoxified alcoholic patients with alcohol craving: a positron emission tomography study using carbon 11-labeled carfentanil.

    Science.gov (United States)

    Heinz, Andreas; Reimold, Matthias; Wrase, Jana; Hermann, Derik; Croissant, Bernhard; Mundle, Götz; Dohmen, Bernhard M; Braus, Dieter F; Braus, Dieter H; Schumann, Gunter; Machulla, Hans-Jürgen; Bares, Roland; Mann, Karl

    2005-01-01

    The pleasant effects of food and alcohol intake are partially mediated by mu-opiate receptors in the ventral striatum, a central area of the brain reward system. Blockade of mu-opiate receptors with naltrexone reduces the relapse risk among some but not all alcoholic individuals. To test the hypothesis that alcohol craving is pronounced among alcoholic individuals with a high availability of mu-opiate receptors in the brain reward system. Patients and comparison sample. The availability of central mu-opiate receptors was measured in vivo with positron emission tomography (PET) and the radioligand carbon 11-labeled carfentanil in the ventral striatum and compared with the severity of alcohol craving as assessed by the Obsessive Compulsive Drinking Scale (OCDS). Hospitalized care. Volunteer sample of 25 male alcohol-dependent inpatients assessed after detoxification of whom 12 underwent PET again 5 weeks later. Control group of 10 healthy men. After 1 to 3 weeks of abstinence, the availability of mu-opiate receptors in the ventral striatum, including the nucleus accumbens, was significantly elevated in alcoholic patients compared with healthy controls and remained elevated when 12 alcoholic patients had these levels measured 5 weeks later (P<.05 corrected for multiple testing). Higher availability of mu-opiate receptors in this brain area correlated significantly with the intensity of alcohol craving as assessed by the OCDS. Abstinent alcoholic patients displayed an increase in mu-opiate receptors in the ventral striatum, including the nucleus accumbens, which correlated with the severity of alcohol craving. These findings point to a neuronal correlate of alcohol urges.

  14. Women's Limited Choice and Availability of Modern Contraception at Retail Outlets and Public-Sector Facilities in Luanda, Angola, 2012-2015.

    Science.gov (United States)

    Nieto-Andrade, Benjamin; Fidel, Eva; Simmons, Rebecca; Sievers, Dana; Fedorova, Anya; Bell, Suzanne; Weidert, Karen; Prata, Ndola

    2017-03-24

    In Angola, many women want to use family planning but lack access to affordable and preferred methods. This article assesses the link between women's choice and availability of contraceptive methods in Luanda, Angola, drawing on data from 3 surveys: a 2012 survey among women ages 15-49 and 2 retail surveys conducted in 2014 and 2015 among outlets and facilities offering contraceptive methods. Descriptive statistics for women's contraceptive knowledge, use, and preferred methods were stratified by age group. We report the percentage of establishments offering different methods and brands of modern contraception, and the mean price, volume of units sold, and value (Angolan Kwanzas) for each brand. Data from the 2 retail surveys are compared to measure changes in availability over time. Results show that 51% of women reported having an unwanted pregnancy. Less than 40% of women knew about long-acting reversible contraceptives (LARCs). Overall, the method most commonly used was male condoms (32.1%), with a substantial proportion (17.3%) of women not using their preferred contraceptive. Trends in contraceptive use mirror availability: in 2015, condoms were available in 73.6% of outlets/facilities, while LARC methods were available in less than 10%. The availability of different methods also dropped significantly between 2014 and 2015-by up to 15 percentage points-with a subsequent price increase in many brands. To meet women's needs for contraception and make informed choice possible, Angola should reinforce demand creation and contraceptive supply in both the public and private sectors through behavior change programs aimed at both women and providers, improved quality of services, training of health personnel on method options and delivery, and improved supply chain distribution of contraceptives. This will allow women to find the methods and brands that best suit their needs, preferences, and ability to pay. © Nieto-Andrade et al.

  15. Women's Limited Choice and Availability of Modern Contraception at Retail Outlets and Public-Sector Facilities in Luanda, Angola, 2012–2015

    Science.gov (United States)

    Nieto-Andrade, Benjamin; Fidel, Eva; Simmons, Rebecca; Sievers, Dana; Fedorova, Anya; Bell, Suzanne; Weidert, Karen; Prata, Ndola

    2017-01-01

    ABSTRACT In Angola, many women want to use family planning but lack access to affordable and preferred methods. This article assesses the link between women's choice and availability of contraceptive methods in Luanda, Angola, drawing on data from 3 surveys: a 2012 survey among women ages 15–49 and 2 retail surveys conducted in 2014 and 2015 among outlets and facilities offering contraceptive methods. Descriptive statistics for women's contraceptive knowledge, use, and preferred methods were stratified by age group. We report the percentage of establishments offering different methods and brands of modern contraception, and the mean price, volume of units sold, and value (Angolan Kwanzas) for each brand. Data from the 2 retail surveys are compared to measure changes in availability over time. Results show that 51% of women reported having an unwanted pregnancy. Less than 40% of women knew about long-acting reversible contraceptives (LARCs). Overall, the method most commonly used was male condoms (32.1%), with a substantial proportion (17.3%) of women not using their preferred contraceptive. Trends in contraceptive use mirror availability: in 2015, condoms were available in 73.6% of outlets/facilities, while LARC methods were available in less than 10%. The availability of different methods also dropped significantly between 2014 and 2015—by up to 15 percentage points—with a subsequent price increase in many brands. To meet women's needs for contraception and make informed choice possible, Angola should reinforce demand creation and contraceptive supply in both the public and private sectors through behavior change programs aimed at both women and providers, improved quality of services, training of health personnel on method options and delivery, and improved supply chain distribution of contraceptives. This will allow women to find the methods and brands that best suit their needs, preferences, and ability to pay. PMID:28193721

  16. Reduced Availability of Sugar-Sweetened Beverages and Diet Soda Has a Limited Impact on Beverage Consumption Patterns in Maine High School Youth

    Science.gov (United States)

    Whatley Blum, Janet E.; Davee, Anne-Marie; Beaudoin, Christina M.; Jenkins, Paul L.; Kaley, Lori A.; Wigand, Debra A.

    2008-01-01

    Objective: To examine change in high school students' beverage consumption patterns pre- and post-intervention of reduced availability of sugar-sweetened beverages (SSB) and diet soda in school food venues. Design: A prospective, quasi-experimental, nonrandomized study design. Setting: Public high schools. Participants: A convenience sample from…

  17. Electro-deposition of Pd on Carbon paper and Ni foam via surface limited redox-replacement reaction for oxygen reduction reaction: Presentation

    CSIR Research Space (South Africa)

    Modibedi, M

    2013-03-01

    Full Text Available the electrochemical atomic layer deposition technique. Pd was deposited on carbon paper and Ni foam substrates using Cu as a sacrificial metal following the procedure published by Mkwizu et al. The electrochemical activity of the prepared nanostructures towards ORR...

  18. Magnetic resonance colonography with a limited bowel preparation and automated carbon dioxide insufflation in comparison to conventional colonoscopy: Patient burden and preferences

    Energy Technology Data Exchange (ETDEWEB)

    Paardt, M.P. van der, E-mail: m.p.vanderpaardt@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Boellaard, T.N., E-mail: t.n.boellaard@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Zijta, F.M., E-mail: fmzijta@yahoo.com [Department of Radiology, Medisch Centrum Haaglanden, Den Haag (Netherlands); Baak, L.C., E-mail: l.c.baak@olvg.nl [Department of Gastroenterology and Hepatology, Onze Lieve Vrouwe Gasthuis, Amsterdam (Netherlands); Depla, A.C.T.M., E-mail: actm.depla@slz.nl [Department of Gastroenterology and Hepatology, Slotervaartziekenhuis, Amsterdam (Netherlands); Dekker, E., E-mail: e.dekker@amc.uva.nl [Department of Gastroenterology and Hepatology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Nederveen, A.J., E-mail: a.j.nederveen@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Bipat, S., E-mail: s.bipat@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands); Stoker, J., E-mail: j.stoker@amc.uva.nl [Department of Radiology, Academic Medical Center Amsterdam, Amsterdam (Netherlands)

    2015-01-15

    Highlights: • MR colonography with a limited bowel preparation and automated carbon dioxide insufflation demonstrated less burden compared to colonoscopy. • When discarding the bowel preparation, the examinations were rated equally burdensome. • The majority of patients preferred MR colonography over colonoscopy for their future examination of the bowel. - Abstract: Objectives: To evaluate patient burden and preferences for MR colonography with a limited bowel preparation and automated carbon dioxide insufflation in comparison to conventional colonoscopy. Methods: Symptomatic patients were consecutively recruited to undergo MR colonography with automated carbon dioxide insufflation and a limited bowel preparation followed within four weeks by colonoscopy with a standard bowel cleansing preparation. Four questionnaires regarding burden (on a five-point scale) and preferences (on a seven-point scale) were addressed after MR colonography and colonoscopy and five weeks after colonoscopy. Results: Ninety-nine patients (47 men, 52 women; mean age 62.3, SD 8.7) were included. None of the patients experienced severe or extreme burden from the MR colonography bowel preparation compared to 31.5% of the patients for the colonoscopy bowel preparation. Colonoscopy was rated more burdensome (25.6% severe or extreme burden) compared to MR colonography (5.2% severe or extreme burden) (P < 0.0001). When discarding the bowel preparations, the examinations were rated equally burdensome (P = 0.35). The majority of patients (61.4%) preferred MR colonography compared to colonoscopy (29.5%) immediately after the examinations and five weeks later (57.0% versus 39.5%). Conclusion: MR colonography with a limited bowel preparation and automated carbon dioxide insufflation demonstrated less burden compared to colonoscopy. The majority of patients preferred MR colonography over colonoscopy.

  19. New high (> or =6M/sub sun/) upper mass limit for planetary nebula formation, and a new high lower mass bound for carbon detonation supernova models

    International Nuclear Information System (INIS)

    Tuchman, Y.; Sack, N.; Barkat, Z.

    1978-01-01

    Envelope ejection leading to a planetary nebula has been recently shown to occur as the terminal point of the Mira stage. The ejection is due to a diverging pulsational instability, not to a dynamical one. It is found that in this case (and for Population I, mixing length=1 pressure scale height) the upper mass limit for formation of planetary nebulae is at least 6 M/sub sun/. It thus follows that the lower mass limit for realization of carbon detonation model configurations is also at last 6 M/sub sun/

  20. Co-precipitation of phosphate and iron limits mitochondrial phosphate availability in Saccharomyces cerevisiae lacking the yeast frataxin homologue (YFH1).

    Science.gov (United States)

    Seguin, Alexandra; Santos, Renata; Pain, Debkumar; Dancis, Andrew; Camadro, Jean-Michel; Lesuisse, Emmanuel

    2011-02-25

    Saccharomyces cerevisiae cells lacking the yeast frataxin homologue (Δyfh1) accumulate iron in the mitochondria in the form of nanoparticles of ferric phosphate. The phosphate content of Δyfh1 mitochondria was higher than that of wild-type mitochondria, but the proportion of mitochondrial phosphate that was soluble was much lower in Δyfh1 cells. The rates of phosphate and iron uptake in vitro by isolated mitochondria were higher for Δyfh1 than wild-type mitochondria, and a significant proportion of the phosphate and iron rapidly became insoluble in the mitochondrial matrix, suggesting co-precipitation of these species after oxidation of iron by oxygen. Increasing the amount of phosphate in the medium decreased the amount of iron accumulated by Δyfh1 cells and improved their growth in an iron-dependent manner, and this effect was mostly transcriptional. Overexpressing the major mitochondrial phosphate carrier, MIR1, slightly increased the concentration of soluble mitochondrial phosphate and significantly improved various mitochondrial functions (cytochromes, [Fe-S] clusters, and respiration) in Δyfh1 cells. We conclude that in Δyfh1 cells, soluble phosphate is limiting, due to its co-precipitation with iron.

  1. Carbon-13 conundrums: limitations and cautions in the use of stable isotope analysis in stream ecotonal research

    International Nuclear Information System (INIS)

    France, R.L.

    1996-01-01

    A secondary analysis of literature was compiled and performed on the δ 13 C values for allochthonous litter, attached algae and consumers in stream ecosystems, finding that 'existing data conflict as to the capability of stable isotope analysis (SIA) for distinguishing carbon pathways'. The paper is in defence of the work previously performed and suggests caution when using stream SIA research. 48 refs

  2. 76 FR 3612 - Circular Welded Carbon Steel Pipes and Tubes From Taiwan; Extension of Time Limit for Preliminary...

    Science.gov (United States)

    2011-01-20

    ... DEPARTMENT OF COMMERCE International Trade Administration [A-583-008] Circular Welded Carbon Steel... Steel Pipes and Tubes From Taiwan: Notice of Partial Rescission of Antidumping Duty Administrative... complete the preliminary results of this review within the original time frame because we require...

  3. Studies of HVC Plasticity in Adult Canaries Reveal Social Effects and Sex Differences as Well as Limitations of Multiple Markers Available to Assess Adult Neurogenesis.

    Science.gov (United States)

    Shevchouk, Olesya T; Ball, Gregory F; Cornil, Charlotte A; Balthazart, Jacques

    2017-01-01

    In songbirds, neurogenesis in the song control nucleus HVC is sensitive to the hormonal and social environment but the dynamics of this process is difficult to assess with a single exogenous marker of new neurons. We simultaneously used three independent markers to investigate HVC neurogenesis in male and female canaries. Males were castrated, implanted with testosterone and housed either alone (M), with a female (M-F) or with another male (M-M) while females were implanted with 17β-estradiol and housed with a male (F-M). All subjects received injections of the two thymidine analogues, BrdU and of EdU, respectively 21 and 10 days before brain collection. Cells containing BrdU or EdU or expressing doublecortin (DCX), which labels newborn neurons, were quantified. Social context and sex differentially affected total BrdU+, EdU+, BrdU+EdU- and DCX+ populations. M-M males had a higher density of BrdU+ cells in the ventricular zone adjacent to HVC and of EdU+ in HVC than M-F males. M birds had a higher ratio of BrdU+EdU- to EdU+ cells than M-F subjects suggesting higher survival of newer neurons in the former group. Total number of HVC DCX+ cells was lower in M-F than in M-M males. Sex differences were also dependent of the type of marker used. Several technical limitations associated with the use of these multiple markers were also identified. These results indicate that proliferation, recruitment and survival of new neurons can be independently affected by environmental conditions and effects can only be fully discerned through the use of multiple neurogenesis markers.

  4. The utility and limitations of current web-available algorithms to predict peptides recognized by CD4 T cells in response to pathogen infection #

    Science.gov (United States)

    Chaves, Francisco A.; Lee, Alvin H.; Nayak, Jennifer; Richards, Katherine A.; Sant, Andrea J.

    2012-01-01

    The ability to track CD4 T cells elicited in response to pathogen infection or vaccination is critical because of the role these cells play in protective immunity. Coupled with advances in genome sequencing of pathogenic organisms, there is considerable appeal for implementation of computer-based algorithms to predict peptides that bind to the class II molecules, forming the complex recognized by CD4 T cells. Despite recent progress in this area, there is a paucity of data regarding their success in identifying actual pathogen-derived epitopes. In this study, we sought to rigorously evaluate the performance of multiple web-available algorithms by comparing their predictions and our results using purely empirical methods for epitope discovery in influenza that utilized overlapping peptides and cytokine Elispots, for three independent class II molecules. We analyzed the data in different ways, trying to anticipate how an investigator might use these computational tools for epitope discovery. We come to the conclusion that currently available algorithms can indeed facilitate epitope discovery, but all shared a high degree of false positive and false negative predictions. Therefore, efficiencies were low. We also found dramatic disparities among algorithms and between predicted IC50 values and true dissociation rates of peptide:MHC class II complexes. We suggest that improved success of predictive algorithms will depend less on changes in computational methods or increased data sets and more on changes in parameters used to “train” the algorithms that factor in elements of T cell repertoire and peptide acquisition by class II molecules. PMID:22467652

  5. Limiting the financial risks of electricity generation capital investments under carbon constraints: Applications and opportunities for public policies and private investments

    Science.gov (United States)

    Newcomer, Adam

    Increasing demand for electricity and an aging fleet of generators are the principal drivers behind an increasing need for a large amount of capital investments in the US electric power sector in the near term. The decisions (or lack thereof) by firms, regulators and policy makers in response to this challenge have long lasting consequences, incur large economic and environmental risks, and must be made despite large uncertainties about the future operating and business environment. Capital investment decisions are complex: rates of return are not guaranteed; significant uncertainties about future environmental legislation and regulations exist at both the state and national levels---particularly about carbon dioxide emissions; there is an increasing number of shareholder mandates requiring public utilities to reduce their exposure to potentially large losses from stricter environmental regulations; and there are significant concerns about electricity and fuel price levels, supplies, and security. Large scale, low carbon electricity generation facilities using coal, such as integrated gasification combined cycle (IGCC) facilities coupled with carbon capture and sequestration (CCS) technologies, have been technically proven but are unprofitable in the current regulatory and business environment where there is no explicit or implicit price on carbon dioxide emissions. The paper examines two separate scenarios that are actively discussed by policy and decision makers at corporate, state and national levels: a future US electricity system where coal plays a role; and one where the role of coal is limited or nonexistent. The thesis intends to provide guidance for firms and policy makers and outline applications and opportunities for public policies and for private investment decisions to limit financial risks of electricity generation capital investments under carbon constraints.

  6. Carbon Inputs From Riparian Vegetation Limit Oxidation of Physically Bound Organic Carbon Via Biochemical and Thermodynamic Processes: OC Oxidation Processes Across Vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Emily B. [Pacific Northwest National Laboratory, Richland WA USA; Tfaily, Malak M. [Environmental Molecular Sciences Laboratory, Richland WA USA; Crump, Alex R. [Pacific Northwest National Laboratory, Richland WA USA; Goldman, Amy E. [Pacific Northwest National Laboratory, Richland WA USA; Bramer, Lisa M. [Pacific Northwest National Laboratory, Richland WA USA; Arntzen, Evan [Pacific Northwest National Laboratory, Richland WA USA; Romero, Elvira [Pacific Northwest National Laboratory, Richland WA USA; Resch, C. Tom [Pacific Northwest National Laboratory, Richland WA USA; Kennedy, David W. [Pacific Northwest National Laboratory, Richland WA USA; Stegen, James C. [Pacific Northwest National Laboratory, Richland WA USA

    2017-12-01

    In light of increasing terrestrial carbon (C) transport across aquatic boundaries, the mechanisms governing organic carbon (OC) oxidation along terrestrial-aquatic interfaces are crucial to future climate predictions. Here, we investigate biochemistry, metabolic pathways, and thermodynamics corresponding to OC oxidation in the Columbia River corridor. We leverage natural vegetative differences to encompass variation in terrestrial C inputs. Our results suggest that decreases in terrestrial C deposition associated with diminished riparian vegetation induce oxidation of physically-bound (i.e., mineral and microbial) OC at terrestrial-aquatic interfaces. We also find that contrasting metabolic pathways oxidize OC in the presence and absence of vegetation and—in direct conflict with the concept of ‘priming’—that inputs of water-soluble and thermodynamically-favorable terrestrial OC protects bound-OC from oxidation. Based on our results, we propose a mechanistic conceptualization of OC oxidation along terrestrial-aquatic interfaces that can be used to model heterogeneous patterns of OC loss under changing land cover distributions.

  7. Carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Hennebutte, H G; Goutal, E

    1921-07-04

    Materials such as coal, peat, or schist are subjected to a rising temperature in successive stages in apparatus in which the distillation products are withdrawn at each stage. For example in a three-stage process, the acid products of the first or low-temperature stage are fixed in a suitable reagent, the basic products from a second or higher-temperature stage are absorbed in an acid reagent, hydrocarbons being retained by solvents, while the third are subjected to a pyrogenation process carried out in a closed vessel. Wherein the material is subjected in stages to a rising temperature, the gasified products being withdrawn at each stage, and are prevented as far as possible from mixing with the carbonized products.

  8. Can the availability of unrestricted financial support improve the quality of care of thalassemics in a center with limited resources? A single center study from India

    Directory of Open Access Journals (Sweden)

    Prantar Chakrabarti

    2012-12-01

    Full Text Available Comprehensive management of thalassemia demands a multidisciplinary approach, sufficient financial resources, carefully developed expertise of the care givers, as well as significant compliance on the patients’ part. Studies exploring the utility of unrestricted financing within the existing infrastructure, for the management of thalassemia, particularly in the context of a developing country, are scarce. This study aimed to assess the impact of sponsored comprehensive care compared to the routine care of thalassemics provided at Institute of Haematology and Transfusion Medicine, Kolkata, India. Two hundred and twenty patients were selected for the study and distributed in two arms. Regular monthly follow up was done including a Health Related Quality of Life (HRQoL assessment with SF 36 v2 (validated Bengali version. Patients receiving sponsored comprehensive care showed a significant improvement in the mean hemoglobin levels and decrease in mean ferritin. HRQoL assessment revealed a better score in the physical domain though the mental health domain score was not significantly better at nine months. Unrestricted financial support in the form of comprehensive care has a positive impact on the thalassemia patients in a developing country not only in terms of clinical parameters but also in health related quality of life. 地中海贫血症的综合管理需要多学科的研究方法、充足的财政资源,护理人员应具备丰富的专业知识,并且患者应尽可能服从安排。探讨现有基础设施内无限制财政支持的实用性和地中海贫血症管理(尤其是在发展中国家)的研究甚少。 此研究旨在评估与印度加尔各答血液及输血医学会提供的地中海贫血症常规护理相比,综合护理对患者的影响 。 此研究筛选了 220名患者,并分为两组进行研究。每月定期跟进两组患者情况,包括使用第2版SF 36(经验证的孟加拉语版本)进行

  9. Nonlinear optical and optical limiting properties of fullerene, multi-walled carbon nanotubes, graphene and their derivatives with oxygen-containing functional groups

    International Nuclear Information System (INIS)

    Zhang, Xiao-Liang; Li, Xiao-Chun; Liu, Zhi-Bo; Yan, Xiao-Qing; Tian, Jian-Guo; Chen, Yong-Sheng

    2015-01-01

    Nonlinear optical properties (NLO) and optical limiting effect of fullerene (C 60 ), multi-walled carbon nanotubes (MWNTs), reduced graphene oxide (RGO) and their oxygenated derivatives were investigated by open-aperture Z-scan technique with nanosecond pulses at 532 nm. C 60 functionalized by oxygen-containing functional groups exhibits weaker NLO properties than that of pristine C 60 . Graphene oxide (GO) with many oxygen-containing functional groups also shows weaker NLO properties than that of RGO. That can be attributed to the disruption of conjugative structures of C 60 and graphene by oxygen-containing functional groups. However, MWNTs and their oxygenated derivatives exhibit comparable NLO properties due to the small weight ratio of these oxygen-containing groups. To investigate the correlation between structures and NLO response for these carbon nanomaterials with different dimensions, nonlinear scattered signal spectra versus input fluence were also measured. (paper)

  10. The physiological response of two green calcifying algae from the Great Barrier Reef towards high dissolved inorganic and organic carbon (DIC and DOC) availability.

    Science.gov (United States)

    Meyer, Friedrich Wilhelm; Vogel, Nikolas; Teichberg, Mirta; Uthicke, Sven; Wild, Christian

    2015-01-01

    Increasing dissolved inorganic carbon (DIC) concentrations associated with ocean acidification can affect marine calcifiers, but local factors, such as high dissolved organic carbon (DOC) concentrations through sewage and algal blooms, may interact with this global factor. For calcifying green algae of the genus Halimeda, a key tropical carbonate producer that often occurs in coral reefs, no studies on these interactions have been reported. These data are however urgently needed to understand future carbonate production. Thus, we investigated the independent and combined effects of DIC (pCO2 402 μatm/ pHtot 8.0 and 996 μatm/ pHtot 7.7) and DOC (added as glucose in 0 and 294 μmol L-1) on growth, calcification and photosynthesis of H. macroloba and H. opuntia from the Great Barrier Reef in an incubation experiment over 16 days. High DIC concentrations significantly reduced dark calcification of H. opuntia by 130 % and led to net dissolution, but did not affect H. macroloba. High DOC concentrations significantly reduced daily oxygen production of H. opuntia and H. macroloba by 78 % and 43 %, respectively, and significantly reduced dark calcification of H. opuntia by 70%. Combined high DIC and DOC did not show any interactive effects for both algae, but revealed additive effects for H. opuntia where the combination of both factors reduced dark calcification by 162 % compared to controls. Such species-specific differences in treatment responses indicate H. opuntia is more susceptible to a combination of high DIC and DOC than H. macroloba. From an ecological perspective, results further suggest a reduction of primary production for Halimeda-dominated benthic reef communities under high DOC concentrations and additional decreases of carbonate accretion under elevated DIC concentrations, where H. opuntia dominates the benthic community. This may reduce biogenic carbonate sedimentation rates and hence the buffering capacity against further ocean acidification.

  11. Water availability as a driver of spatial and temporal variability in vegetation in the La Mancha plain (Spain): Implications for the land-surface energy, water and carbon budget

    Science.gov (United States)

    Los, Sietse

    2017-04-01

    Vegetation is water limited in large areas of Spain and therefore a close link exists between vegetation greenness observed from satellite and moisture availability. Here we exploit this link to infer spatial and temporal variability in moisture from MODIS NDVI data and thermal data. Discrepancies in the precipitation - vegetation relationship indicate areas with an alternative supply of water (i.e. not rainfall), this can be natural where moisture is supplied by upwelling groundwater, or can be artificial where crops are irrigated. As a result spatial and temporal variability in vegetation in the La Mancha Plain appears closely linked to topography, geology, rainfall and land use. Crop land shows large variability in year-to-year vegetation greenness; for some areas this variability is linked to variability in rainfall but in other cases this variability is linked to irrigation. The differences in irrigation treatment within one plant functional type, in this case crops, will lead to errors in land surface models when ignored. The magnitude of these effects on the energy, carbon and water balance are assessed at the scale of 250 m to 200 km. Estimating the water balance correctly is of particular important since in some areas in Spain more water is used for irrigation than is supplemented by rainfall.

  12. Human responses to carbon dioxide, a follow-up study at recommended exposure limits in non-industrial environments

    DEFF Research Database (Denmark)

    Zhang, Xiaojing; Wargocki, Pawel; Lian, Zhiwei

    2016-01-01

    To extend the results of a previous study on the effects of carbon dioxide (CO2) and bioeffluents on humans, the new study reported in this paper was carried out. The purpose of this study was to examine, whether exposure to CO2 at 5000 ppm would cause sensory discomfort, evoke acute health...... no effect on perceived air quality or physiological responses except for end-tidal CO2 (ETCO2), which increased more (to 5.3 kPa) than it was in the reference condition (5.1 kPa). Other results indicate additionally that a 2.5-h exposure to CO2 up to 5000 ppm did not increase intensity of health symptoms...

  13. High atmospheric demand for water can limit forest carbon uptake and transpiration as severely as dry soil

    Science.gov (United States)

    Benjamin N. Sulman; Daniel Tyler Roman; Koong Yi; Lixin Wang; Richard P. Phillips; Kimberly A. Novick

    2016-01-01

    When stressed by low soil water content (SWC) or high vapor pressure deficit (VPD), plants close stomata, reducing transpiration and photosynthesis. However, it has historically been difficult to disentangle the magnitudes of VPD compared to SWC limitations on ecosystem-scale fluxes. We used a 13 year record of eddy covariance measurements from a forest in south...

  14. Adaptation of Bacillus subtilis carbon core metabolism to simultaneous nutrient limitation and osmotic challenge : a multi-omics perspective

    NARCIS (Netherlands)

    Kohlstedt, Michael; Sappa, Praveen K; Meyer, Hanna; Maaß, Sandra; Zaprasis, Adrienne; Hoffmann, Tamara; Becker, Judith; Steil, Leif; Hecker, Michael; van Dijl, Jan Maarten; Lalk, Michael; Mäder, Ulrike; Stülke, Jörg; Bremer, Erhard; Völker, Uwe; Wittmann, Christoph

    The Gram-positive bacterium Bacillus subtilis encounters nutrient limitations and osmotic stress in its natural soil ecosystem. To ensure survival and sustain growth, highly integrated adaptive responses are required. Here, we investigated the system-wide response of B.subtilis to different,

  15. Evaluation of a hierarchy of models reveals importance of substrate limitation for predicting carbon dioxide and methane exchange in restored wetlands

    Science.gov (United States)

    Oikawa, P. Y.; Jenerette, G. D.; Knox, S. H.; Sturtevant, C.; Verfaillie, J.; Dronova, I.; Poindexter, C. M.; Eichelmann, E.; Baldocchi, D. D.

    2017-01-01

    Wetlands and flooded peatlands can sequester large amounts of carbon (C) and have high greenhouse gas mitigation potential. There is growing interest in financing wetland restoration using C markets; however, this requires careful accounting of both CO2 and CH4 exchange at the ecosystem scale. Here we present a new model, the PEPRMT model (Peatland Ecosystem Photosynthesis Respiration and Methane Transport), which consists of a hierarchy of biogeochemical models designed to estimate CO2 and CH4 exchange in restored managed wetlands. Empirical models using temperature and/or photosynthesis to predict respiration and CH4 production were contrasted with a more process-based model that simulated substrate-limited respiration and CH4 production using multiple carbon pools. Models were parameterized by using a model-data fusion approach with multiple years of eddy covariance data collected in a recently restored wetland and a mature restored wetland. A third recently restored wetland site was used for model validation. During model validation, the process-based model explained 70% of the variance in net ecosystem exchange of CO2 (NEE) and 50% of the variance in CH4 exchange. Not accounting for high respiration following restoration led to empirical models overestimating annual NEE by 33-51%. By employing a model-data fusion approach we provide rigorous estimates of uncertainty in model predictions, accounting for uncertainty in data, model parameters, and model structure. The PEPRMT model is a valuable tool for understanding carbon cycling in restored wetlands and for application in carbon market-funded wetland restoration, thereby advancing opportunity to counteract the vast degradation of wetlands and flooded peatlands.

  16. Accretion onto Carbon-Oxygen White Dwarfs as a possible mechanism for growth to the Chandrasekhar Limit

    Science.gov (United States)

    Starrfield, Sumner; Bose, Maitrayee; Iliadis, Christian; Hix, William R.; José, Jordi; Hernanz, Margarita

    2017-08-01

    We have continued our studies of accretion onto white dwarfs by following the evolution of thermonuclear runaways (TNRs) on Carbon Oxygen (CO) white dwarfs. We have varied the mass of the white dwarf and the composition of the accreted material. We use the results of the multi-dimensional studies of TNRs in white dwarfs, accreting only Solar matter, which show that sufficient core material is dredged-up by the TNR and then ejected by the explosion to agree with the observations of the ejecta abundances. We have also found that the initial 12C abundance is inversely proportional to the amount of material accreted prior to the TNR. Therefore, we first accrete Solar material and follow the evolution until a TNR occurs. Because the 12C abundance is significantly smaller then if we had initially mixed the accreting gas with the carbon-oxygen core, more matter takes part in the explosion than if we had begun the evolution with the mixed composition. We then instantaneously switch the composition to a mixture with either 25% core material or 50% core material (plus accreted material) and follow the resulting evolution of the TNR. We use our 1D, Lagrangian, hydrodynamic code: NOVA. We report on the results of these new simulations and compare the ejecta abundances to those measured in pre-solar grains that are thought to arise from classical nova explosions. These results will also be compared to recent results with SHIVA (Josè and Hernanz). We find that there are some white dwarf masses where significantly less mass is ejected than accreted during the Classical Nova event and, therefore, the white dwarf is growing in mass as a result of the accretion and in spite of the resulting explosion.This work was supported in part by NASA under the Astrophysics Theory Program grant 14-ATP14-0007 and the U.S. DOE under Contract No. DE-FG02- 97ER41041. SS acknowledges partial support from NASA, NSF, and HST grants to ASU and WRH is supported by the U.S. Department of Energy, Office

  17. Simultaneous effect of nitrate (NO3- concentration, carbon dioxide (CO2 supply and nitrogen limitation on biomass, lipids, carbohydrates and proteins accumulation in Nannochloropsis oculata

    Directory of Open Access Journals (Sweden)

    Aarón Millán-Oropeza

    2015-03-01

    Full Text Available Biodiesel from microalgae is a promising technology. Nutrient limitation and the addition of CO2 are two strategies to increase lipid content in microalgae. There are two different types of nitrogen limitation, progressive and abrupt limitation. In this work, the simultaneous effect of initial nitrate concentration, addition of CO2, and nitrogen limitation on biomass, lipid, protein and carbohydrates accumulation were analyzed. An experimental design was established in which initial nitrogen concentration, culture time and CO2 aeration as independent numerical variables with three levels were considered. Nitrogen limitation was taken into account as a categorical independent variable. For the experimental design, all the experiments were performed with progressive nitrogen limitation. The dependent response variables were biomass, lipid production, carbohydrates and proteins. Subsequently, comparison of both types of limitation i.e. progressive and abrupt limitation, was performed. Nitrogen limitation in a progressive mode exerted a greater effect on lipid accumulation. Culture time, nitrogen limitation and the interaction of initial nitrate concentration with nitrogen limitation had higher influences on lipids and biomass production. The highest lipid production and productivity were at 582 mgL-1 (49.7 % lipid, dry weight basis and 41.5 mgL-1d-1, respectively; under the following conditions: 250 mgL-1 of initial nitrate concentration, CO2 supply of 4% (v/v, 12 d of culturing and 2 d in state of nitrogen starvation induced by progressive limitation. This work presents a novel way to perform simultaneous analysis of the effect of the initial concentration of nitrate, nitrogen limitation, and CO2 supply on growth and lipid production of Nannochloropsis oculata, with the aim to produce potential biofuels feedstock.

  18. Electrodeposition of Pd based binary catalysts on Carbon paper via surface limited redox-replacement reaction for oxygen reduction reaction

    CSIR Research Space (South Africa)

    Modibedi, RM

    2014-05-01

    Full Text Available Direct alcohol fuel cells (DAFCs) continue to extensive attention as potential power sources for portable and stationary applications. The oxygen reduction reaction (ORR) involving the four electron transfer remains a challenge for DAFCs due to its...

  19. Utilizing electromagnetic properties to determine the micro-plastic limit of low-carbon steel CSN 411375

    Czech Academy of Sciences Publication Activity Database

    Gajdoš, Lubomír; Šperl, Martin; Kaiser, J.; Mentl, V.

    2014-01-01

    Roč. 46, č. 1 (2014), s. 23-33 ISSN 1383-5416 R&D Projects: GA ČR(CZ) GAP105/10/2052 Institutional support: RVO:68378297 Keywords : damage * fatigue * microplastic limit * electrical impedance Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.815, year: 2014 http://iospress.metapress.com/content/j16473863q2thh40/?p=09ecef602ca94ee08740cc9f2e44ec32&pi=2

  20. Oxygen Response of the Wine Yeast Saccharomyces cerevisiae EC1118 Grown under Carbon-Sufficient, Nitrogen-Limited Enological Conditions

    Science.gov (United States)

    Aceituno, Felipe F.; Orellana, Marcelo; Torres, Jorge; Mendoza, Sebastián; Slater, Alex W.; Melo, Francisco

    2012-01-01

    Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations. PMID:23001663

  1. Oxygen response of the wine yeast Saccharomyces cerevisiae EC1118 grown under carbon-sufficient, nitrogen-limited enological conditions.

    Science.gov (United States)

    Aceituno, Felipe F; Orellana, Marcelo; Torres, Jorge; Mendoza, Sebastián; Slater, Alex W; Melo, Francisco; Agosin, Eduardo

    2012-12-01

    Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations.

  2. A methodology for calculating transport emissions in cities with limited traffic data: Case study of diesel particulates and black carbon emissions in Murmansk.

    Science.gov (United States)

    Kholod, N; Evans, M; Gusev, E; Yu, S; Malyshev, V; Tretyakova, S; Barinov, A

    2016-03-15

    This paper presents a methodology for calculating exhaust emissions from on-road transport in cities with low-quality traffic data and outdated vehicle registries. The methodology consists of data collection approaches and emission calculation methods. For data collection, the paper suggests using video survey and parking lot survey methods developed for the International Vehicular Emissions model. Additional sources of information include data from the largest transportation companies, vehicle inspection stations, and official vehicle registries. The paper suggests using the European Computer Programme to Calculate Emissions from Road Transport (COPERT) 4 model to calculate emissions, especially in countries that implemented European emissions standards. If available, the local emission factors should be used instead of the default COPERT emission factors. The paper also suggests additional steps in the methodology to calculate emissions only from diesel vehicles. We applied this methodology to calculate black carbon emissions from diesel on-road vehicles in Murmansk, Russia. The results from Murmansk show that diesel vehicles emitted 11.7 tons of black carbon in 2014. The main factors determining the level of emissions are the structure of the vehicle fleet and the level of vehicle emission controls. Vehicles without controls emit about 55% of black carbon emissions. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Capillary pressure - saturation relations in quartz and carbonate sands: Limitations for correlating capillary and wettability influences on air, oil, and supercritical CO2 trapping

    Science.gov (United States)

    Tokunaga, T. K.; Wang, S.; Wan, J.; Dong, W.; Kim, Y.

    2016-12-01

    Capillary pressure (Pc) - saturation (Sw) relations are essential for predicting equilibrium and flow of immiscible fluid pairs in soils and deeper geologic formations. In systems that are difficult to measure, behavior is often estimated based on capillary scaling of easily measured Pc-Sw relations (e.g., air-water, and oil-water), yet the reliability of such approximations needs to be examined. In this study, seventeen sets of brine drainage and imbibition curves were measured with air-brine, decane-brine, and supercritical (sc) CO2-brine in homogeneous quartz and carbonate sands, using porous plate systems under ambient (0.1 MPa, 23 °C) and reservoir (12.0 MPa, 45 °C) conditions. Comparisons between these measurements showed significant differences in residual nonwetting phase saturation, Snw,r. Through applying capillary scaling, changes in interfacial properties were indicated, particularly wettability. With respect to the residual trapping of the nonwetting phases, Snwr, CO2 > Snwr, decane > Snwr, air. Decane-brine and scCO2-brine Pc-Sw curves deviated significantly from predictions assuming hydrophilic interactions. Moreover, neither the scaled capillary behavior nor Snw,r for scCO2-brine were well represented by decane-brine, apparently because of differences in wettability and viscosities, indicating limitations for using decane (and other organic liquids) as a surrogate fluid in studies intended to apply to geological carbon sequestration. Thus, challenges remain in applying scaling for predicting capillary trapping and multiphase displacement processes across such diverse fields as vadose zone hydrology, enhanced oil recovery, and geologic carbon sequestration.

  4. 100 nm scale low-noise sensors based on aligned carbon nanotube networks: overcoming the fundamental limitation of network-based sensors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Minbaek; Lee, Joohyung; Kim, Tae Hyun; Lee, Hyungwoo; Lee, Byung Yang; Hong, Seunghun [Department of Physics and Astronomy, Seoul National University, Shilim-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of); Park, June; Seong, Maeng-Je [Department of Physics, Chung-Ang University, Heukseok-Dong, Dongjak-Gu, Seoul 156-756 (Korea, Republic of); Jhon, Young Min, E-mail: mseong@cau.ac.kr, E-mail: shong@phya.snu.ac.kr [Korea Institute of Science and Technology, Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791 (Korea, Republic of)

    2010-02-05

    Nanoscale sensors based on single-walled carbon nanotube (SWNT) networks have been considered impractical due to several fundamental limitations such as a poor sensitivity and small signal-to-noise ratio. Herein, we present a strategy to overcome these fundamental problems and build highly-sensitive low-noise nanoscale sensors simply by controlling the structure of the SWNT networks. In this strategy, we prepared nanoscale width channels based on aligned SWNT networks using a directed assembly strategy. Significantly, the aligned network-based sensors with narrower channels exhibited even better signal-to-noise ratio than those with wider channels, which is opposite to conventional random network-based sensors. As a proof of concept, we demonstrated 100 nm scale low-noise sensors to detect mercury ions with the detection limit of {approx}1 pM, which is superior to any state-of-the-art portable detection system and is below the allowable limit of mercury ions in drinking water set by most government environmental protection agencies. This is the first demonstration of 100 nm scale low-noise sensors based on SWNT networks. Considering the increased interests in high-density sensor arrays for healthcare and environmental protection, our strategy should have a significant impact on various industrial applications.

  5. 100 nm scale low-noise sensors based on aligned carbon nanotube networks: overcoming the fundamental limitation of network-based sensors

    International Nuclear Information System (INIS)

    Lee, Minbaek; Lee, Joohyung; Kim, Tae Hyun; Lee, Hyungwoo; Lee, Byung Yang; Hong, Seunghun; Park, June; Seong, Maeng-Je; Jhon, Young Min

    2010-01-01

    Nanoscale sensors based on single-walled carbon nanotube (SWNT) networks have been considered impractical due to several fundamental limitations such as a poor sensitivity and small signal-to-noise ratio. Herein, we present a strategy to overcome these fundamental problems and build highly-sensitive low-noise nanoscale sensors simply by controlling the structure of the SWNT networks. In this strategy, we prepared nanoscale width channels based on aligned SWNT networks using a directed assembly strategy. Significantly, the aligned network-based sensors with narrower channels exhibited even better signal-to-noise ratio than those with wider channels, which is opposite to conventional random network-based sensors. As a proof of concept, we demonstrated 100 nm scale low-noise sensors to detect mercury ions with the detection limit of ∼1 pM, which is superior to any state-of-the-art portable detection system and is below the allowable limit of mercury ions in drinking water set by most government environmental protection agencies. This is the first demonstration of 100 nm scale low-noise sensors based on SWNT networks. Considering the increased interests in high-density sensor arrays for healthcare and environmental protection, our strategy should have a significant impact on various industrial applications.

  6. 100 nm scale low-noise sensors based on aligned carbon nanotube networks: overcoming the fundamental limitation of network-based sensors

    Science.gov (United States)

    Lee, Minbaek; Lee, Joohyung; Kim, Tae Hyun; Lee, Hyungwoo; Lee, Byung Yang; Park, June; Jhon, Young Min; Seong, Maeng-Je; Hong, Seunghun

    2010-02-01

    Nanoscale sensors based on single-walled carbon nanotube (SWNT) networks have been considered impractical due to several fundamental limitations such as a poor sensitivity and small signal-to-noise ratio. Herein, we present a strategy to overcome these fundamental problems and build highly-sensitive low-noise nanoscale sensors simply by controlling the structure of the SWNT networks. In this strategy, we prepared nanoscale width channels based on aligned SWNT networks using a directed assembly strategy. Significantly, the aligned network-based sensors with narrower channels exhibited even better signal-to-noise ratio than those with wider channels, which is opposite to conventional random network-based sensors. As a proof of concept, we demonstrated 100 nm scale low-noise sensors to detect mercury ions with the detection limit of ~1 pM, which is superior to any state-of-the-art portable detection system and is below the allowable limit of mercury ions in drinking water set by most government environmental protection agencies. This is the first demonstration of 100 nm scale low-noise sensors based on SWNT networks. Considering the increased interests in high-density sensor arrays for healthcare and environmental protection, our strategy should have a significant impact on various industrial applications.

  7. Potential availability of urban wood biomass in Michigan: Implications for energy production, carbon sequestration and sustainable forest management in the U.S.A

    International Nuclear Information System (INIS)

    MacFarlane, David W.

    2009-01-01

    Tree and wood biomass from urban areas is a potentially large, underutilized resource viewed in the broader social context of biomass production and utilization. Here, data and analysis from a regional study in a 13-county area of Michigan, U.S.A. are combined with data and analysis from several other studies to examine this potential. The results suggest that urban trees and wood waste offer a modest amount of biomass that could contribute significantly more to regional and national bio-economies than it does at present. Better utilization of biomass from urban trees and wood waste could offer new sources of locally generated wood products and bio-based fuels for power and heat generation, reduce fossil fuel consumption, reduce waste disposal costs and reduce pressure on forests. Although wood biomass generally constitutes a 'carbon-neutral' fuel, burning rather than burying urban wood waste may not have a net positive effect on reducing atmospheric CO 2 levels, because it may reduce a significant long term carbon storage pool. Using urban wood residues for wood products may provide the best balance of economic and environmental values for utilization

  8. Moisture availability over the past five centuries indicated by carbon isotopes of Tamarix taklamakanensis leaves in a nebkha profile in the Central Taklimakan Desert, NW China

    Science.gov (United States)

    Lang, Lili; Wang, Xunming; Hua, Ting; Zhang, Caixia

    2013-12-01

    We inferred moisture availability changes from 1555 to 2010 in the Central Taklimakan Desert (NW China) using Chinese tamarisk (Tamarix taklamakanensis) litter deposited within a nebkha that developed in this region. The litter δ13C trends revealed fluctuations of moisture availability: From 1555 to 1785, moisture availability was higher than the long-term average, but from 1555 to 1570, 1585 to 1620, 1640 to 1660, 1675 to 1700, and 1730 to 1755, this region experienced periods with lower than average moisture availability. From 1785 to 1850, significant moisture availability changes occurred, and the region experienced the lowest moisture availability since 1555. From 1850 to the present, the δ13C trends suggested that moisture availability increased. Our results also showed that although moisture availability in this region is controlled by precipitation and evaporation in the Central Taklimakan Desert, temperature variations in the adjacent Kunlun Mountains (whose glacier and snowmelt runoff are dominant water sources for the study area) were potentially more important. Water from these mountains plays an important role in moisture availability due the region’s extremely low precipitation. In addition, although previous studies suggested that the Tarim Basin and its adjacent areas experienced a wet climate for the past several centuries, this suggestion was inconsistent with the reconstructed moisture availability changes in the Central Taklimakan Desert. The moisture availability in the Central Taklimakan was more closely related to temperature variations in the adjacent mountain regions.

  9. The Cu-MOF-199/single-walled carbon nanotubes modified electrode for simultaneous determination of hydroquinone and catechol with extended linear ranges and lower detection limits

    International Nuclear Information System (INIS)

    Zhou, Jian; Li, Xi; Yang, Linlin; Yan, Songlin; Wang, Mengmeng; Cheng, Dan; Chen, Qi; Dong, Yulin; Liu, Peng; Cai, Weiquan; Zhang, Chaocan

    2015-01-01

    A novel electrochemical sensor based on Cu-MOF-199 [Cu-MOF-199 = Cu 3 (BTC) 2 (BTC = 1,3,5-benzenetricarboxylicacid)] and SWCNTs (single-walled carbon nanotubes) was fabricated for the simultaneous determination of hydroquinone (HQ) and catechol (CT). The modification procedure was carried out through casting SWCNTs on the bare glassy carbon electrode (GCE) and followed by the electrodeposition of Cu-MOF-199 on the SWCNTs modified electrode. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were performed to characterize the electrochemical performance and surface characteristics of the as-prepared sensor. The composite electrode exhibited an excellent electrocatalytic activity with increased electrochemical signals towards the oxidation of HQ and CT, owing to the synergistic effect of SWCNTs and Cu-MOF-199. Under the optimized condition, the linear response range were from 0.1 to 1453 μmol L −1 (R HQ  = 0.9999) for HQ and 0.1–1150 μmol L −1 (R CT  = 0.9990) for CT. The detection limits for HQ and CT were as low as 0.08 and 0.1 μmol L −1 , respectively. Moreover, the modified electrode presented the good reproducibility and the excellent anti-interference performance. The analytical performance of the developed sensor for the simultaneous detection of HQ and CT had been evaluated in practical samples with satisfying results. - Highlights: • Cu-MOF-199/SWCNTs/GCE was facilely fabricated by the electrodeposition on SWCNTs/GCE. • An electrochemical sensor for detecting HQ and CT was constructed based on this modified electrode. • The proposed electrochemical sensor showed an extended linear range and lower detection limits. • The proposed electrochemical sensor had an excellent stability and reproducibility.

  10. Soil biogeochemistry properties vary between two boreal forest ecosystems in Quebec: significant differences in soil carbon, available nutrients and iron and aluminium crystallinity

    Science.gov (United States)

    Bastianelli, Carole; Ali, Adam A.; Beguin, Julien; Bergeron, Yves; Grondin, Pierre; Hély, Christelle; Paré, David

    2017-04-01

    At the northernmost extent of the managed forest in Quebec, the boreal forest is currently undergoing an ecological transition from closed-canopy black spruce-moss forests towards open-canopy lichen woodlands, which spread southward. Our study aim was to determine whether this shift could impact soil properties on top of its repercussions on forest productivity or carbon storage. We studied the soil biogeochemical composition of three pedological layers in moss forests (MF) and lichen woodlands (LW) north of the Manicouagan crater in Quebec. The humus layer (FH horizons) was significantly thicker and held more carbon, nitrogen and exchangeable Ca and Mg in MF plots than in LW plots. When considering mineral horizons, we found that the deep C horizon had a very close composition in both ecosystem plots, suggesting that the parent material was of similar geochemical nature. This was expected as all selected sites developed from glacial deposit. Multivariate analysis of surficial mineral B horizon showed however that LW B horizon displayed higher concentrations of Al and Fe oxides than MF B horizon, particularly for inorganic amorphous forms. Conversely, main exchangeable base cations (Ca, Mg) were higher in B horizon of MF than that of LW. Ecosystem types explained much of the variations in the B horizon geochemical composition. We thus suggest that the differences observed in the geochemical composition of the B horizon have a biological origin rather than a mineralogical origin. We also showed that total net stocks of carbon stored in MF soils were three times higher than in LW soils (FH + B horizons, roots apart). Altogether, we suggest that variations in soil properties between MF and LW are linked to a cascade of events involving the impacts of natural disturbances such as wildfires on forest regeneration that determines the of vegetation structure (stand density) and composition (ground cover type) and their subsequent consequences on soil environmental

  11. Strategies for efficiently selecting PHA producing mixed microbial cultures using complex feedstocks: Feast and famine regime and uncoupled carbon and nitrogen availabilities.

    Science.gov (United States)

    Oliveira, Catarina S S; Silva, Carlos E; Carvalho, Gilda; Reis, Maria A

    2017-07-25

    Production of polyhydroxyalkanoates (PHAs) by open mixed microbial cultures (MMCs) has been attracting increasing interest as an alternative technology to PHA production by pure cultures, due to the potential for lower costs associated with the use of open systems (eliminating the requirement for sterile conditions) and the utilisation of cheap feedstock (industrial and agricultural wastes). Such technology relies on the efficient selection of an MMC enriched in PHA-accumulating organisms. Fermented cheese whey, a protein-rich complex feedstock, has been used previously to produce PHA using the feast and famine regime for selection of PHA accumulating cultures. While this selection strategy was found efficient when operated at relatively low organic loading rate (OLR, 2g-CODL -1 d -1 ), great instability and low selection efficiency of PHA accumulating organisms were observed when higher OLR (ca. 6g-CODL -1 d -1 ) was applied. High organic loading is desirable as a means to enhance PHA productivity. In the present study, a new selection strategy was tested with the aim of improving selection for high OLR. It was based on uncoupling carbon and nitrogen supply and was implemented and compared with the conventional feast and famine strategy. For this, two selection reactors were fed with fermented cheese whey applying an OLR of ca. 8.5g-CODL -1 (with 3.8g-CODL -1 resulting from organic acids and ethanol), and operated in parallel under similar conditions, except for the timing of nitrogen supplementation. Whereas in the conventional strategy nitrogen and carbon substrates were added simultaneously at the beginning of the cycle, in the uncoupled substrates strategy, nitrogen addition was delayed to the end of the feast phase (i.e. after exogenous carbon was exhausted). The two different strategies selected different PHA-storing microbial communities, dominated by Corynebacterium and a Xantomonadaceae, respectively with the conventional and the new approaches. The new

  12. Places available**

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    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. TECHNICAL TRAINING Monique Duval tel. 74924 technical.training@cern.ch ** The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses: ACCESS 2000 - niveau 1 : 13 & 14.11.03 (2 jours) C++ for Particle Physicists : 17 – 21.11.03 (6 X 3-hour lectures) Programmation automate Schneider TSX Premium – niveau 2 : 18 – 21.11.03 (4 jours) JAVA 2 Enterprise Edition – Part 1 : WEB Applications : 20 & ...

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    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. Places available The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses : Introduction à Outlook : 19.8.2004 (1 journée) Outlook (short course I) : E-mail : 31.8.2004 (2 hours, morning) Outlook (short course II) : Calendar, Tasks and Notes : 31.8.2004 (2 hours, afternoon) Instructor-led WBTechT Study or Follow-up for Microsoft Applications : 7.9.2004 (morning) Outlook (short course III) : Meetings and Delegation : 7.9.2004 (2 hours, afternoon) Introduction ...

  14. [Not Available].

    Science.gov (United States)

    El Ketani, A; Amir, F; Ali, T B; Hamdani, M; Zaghloul, K

    2006-12-31

    Les enfants célèbrent la fête de Achoura au Maroc par des jeux de feu, ce qui occasionne des blessures oculaires plus au moins graves. Nous rapportons 15 observations de malades traités au Service d'Ophtalmologie Pédiatrique de l'Hôpital 20 Août 1953 de Casablanca. L'âge moyen des patients était de 12 ans et demi, avec des extrêmes de 3 et 25 ans. Les pétards, la première cause des accidents (50%), ont occasionné des contusions oculaires avec parfois un oedème de Berlin (deux cas). L'atteinte oculaire par fusée a occasionné un éclatement de globe et une plaie de paupière. Les bombes de carbone ont été responsables de brûlures de deuxième degré palpébrales et conjonctivo-cornéennes avec de multiples corps étrangers cornéens profonds. Les «étoiles» et la limaille de fer ont provoqué des brûlures cornéennes moins graves avec des corps étrangers superficiels. Les pistolets à bille ont été responsables de contusions oculaires. La réglementation de vente des jeux de feu et la sensibilisation du grand public par les moyens audiovisuels permettraient de prévenir ces blessures oculaires.

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    2003-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. TECHNICAL TRAINING Monique Duval tel. 74924 technical.training@cern.ch ** The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses: Project Planning with MS-Project : 15 & 22.1.2004 (2 days) Joint PVSS JCOP Framework Course : 2 sessions : 2 - 6.2.2004 and 16 - 20-2-2004 (5 days) Hands-on Introduction to Python Programming : 16 - 18.2.2004 (3 days - free of charge) C++ for Particle Physicists : 8 - 12.3.2004 ( 6 X 4-hour sessions)

  1. Places available**

    CERN Multimedia

    2003-01-01

    If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. ** The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses : EXCEL 2000 - niveau 1 : 20 & 22.10.03 (2 jours) CLEAN-2002 : Working in a Cleanroom (free of charge) : 23.10.03 (half day) The EDMS-MTF in practice (free of charge) :  28 -  30.10.03 (6 half-day sessions) AutoCAD 2002 - Level 1 : 3, 4, 12, 13.11.03 (4 days) LabVIEW TestStand ver. 3 : 4 & 5.11.03 (2 days) Introduction to Pspice : 4.11.03 p.m. (half-day) Hands-on Introduction to Python Programm...

  2. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Introduction to Databases :  3 - 4.7.01 (2 days) The JAVA programming language Level 2 : 4 - 6.7.01 (3 days) Enterprise JavaBeans :  9 - 11.7.01 (3 days) Design Patterns :  10 - 12.7.01 (3 days) C++ for Particle Physicists :  23 - 27.7.01 (6 3-hour lectures) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt.

  3. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Introduction to Perl 5 : 2 - 3.7.01 (2 days) Introduction to Databases :  3 - 4.7.01 (2 days) JAVA programming language Level 2 : 4 - 6.7.01 (3 days) Enterprise JavaBeans :  9 - 11.7.01 (3 days) Design Patterns :  10 - 12.7.01 (3 days) C++ for Particle Physicists :  23 - 27.7.01 (6 3-hour lectures) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt.

  4. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: CLEAN-2002 : Travailler en salle blanche (cours gratuit) : 13.08.2002 (matin) Introduction to the CERN Enginnering Data Management System :  27.8.02  (1 day) The CERN Engineering Data Management System for Advanced Users :  28.8.02  (1 day) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : Technical Training or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. Technical Training Monique Duval Tel.74924 monique.duval@cern.ch    

  5. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: C++ Programming Level 2 - Traps & Pitfalls:  16 - 19.7.02 (4 days) Frontpage 2000 - level 1 :  22 - 23.7.02  (2 days) Introduction à Windows 2000 au CERN : 24.7.02 (après-midi) CLEAN-2002 : Travailler en salle blanche (cours gratuit) : 13.08.2002 (matin) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : Technical Training or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. Technical Training Monique Duval Tel.74924 monique.duval@cern.ch

  6. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: December 2002   PCAD Schémas - Débutants :  5 & 6.12.02  (2 jours) PCAD PCB - Débutants :  9 - 11.12.02  (3 jours) FrontPage 2000 - level 1:  9 & 10.12.02  (2 days) Introduction à la CAO Cadence (cours gratuit) :  10 & 11.12.02  (2 jours) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : Technical Training or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. Technical Training Monique Duval Tel.74924 monique.duval@cern.ch

  7. Low moisture availability inhibits the enhancing effect of increased soil temperature on net photosynthesis of white birch (Betula papyrifera) seedlings grown under ambient and elevated carbon dioxide concentrations.

    Science.gov (United States)

    Ambebe, Titus F; Dang, Qing-Lai

    2009-11-01

    White birch (Betula papyrifera Marsh.) seedlings were grown under two carbon dioxide concentrations (ambient: 360 micromol mol(-1) and elevated: 720 micromol mol(-1)), three soil temperatures (5, 15 and 25 degrees C initially, increased to 7, 17 and 27 degrees C, respectively, 1 month later) and three moisture regimes (low: 30-40%; intermediate: 45-55% and high: 60-70% field water capacity) in greenhouses. In situ gas exchange and chlorophyll fluorescence were measured after 2 months of treatments. Net photosynthetic rate (A(n)) of seedlings grown under the intermediate and high moisture regimes increased from low to intermediate T(soil) and then decreased to high T(soil). There were no significant differences between the low and high T(soil), with the exception that A(n) was significantly higher under high than low T(soil) at the high moisture regime. No significant T(soil) effect on A(n) was observed at the low moisture regime. The intermediate T(soil) increased stomatal conductance (g(s)) only at intermediate and high but not at low moisture regime, whereas there were no significant differences between the low and high T(soil) treatments. Furthermore, the difference in g(s) between the intermediate and high T(soil) at high moisture regime was not statistically significant. The low moisture regime significantly reduced the internal to ambient CO2 concentration ratio at all T(soil). There were no significant individual or interactive effects of treatment on maximum carboxylation rate of Rubisco, light-saturated electron transport rate, triose phosphate utilization or potential photochemical efficiency of photosystem II. The results of this study suggest that soil moisture condition should be taken into account when predicting the responses of white birch to soil warming.

  8. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses: Conception de PCB rapides dans le flot Cadence : 11.6.03 (matin) EXCEL 2000 - level 1 : 12 & 13.6.03 (2 days) Introduction to PVSS : 16.6.03 (p.m.) Basic PVSS : 17 - 19.6.03 (3 days) Réalisation de PCB rapides dans le flot Cadence : 17.6.03 (matin) PVSS - JCOP Framework Tutorial : 20.6.03 (1 day) Programmation automate Schneider : Programmation automate Schneider TSX Premium - 2ème niveau : 24 - 27.6.03 (4 jours) - audience : toute personne qui veux maitriser la mise en uvre et la programmation des fonctions spécialisées d'un automate TSX Premium - objectifs : maitriser la mise en uvre et la programmation des fonctions spécialisées d'un automate TSX Premium Cours de sécurité : Etre TSO au CERN : Prochaines sessions : 24, 25 & 27.6.03 - 4, 5 & 7.11.03 (session de 3 jours) ** The number of places available may vary. Please check our Web site to find out the current availability. If you wish to participate in one of these courses, pl...

  9. PLACES AVAILABLE

    CERN Multimedia

    Enseignement Technique; Tél. 74924; Technical Training; Monique Duval; Tel. 74924

    2000-01-01

    Places available Places are available in the following courses:   LabView hands-on 13.11.00 4 hours LabView Basics 1 14 - 16.11.00 3 days Nouveautés de WORD 19 et 20.10.00 2 jours ACCESS 1er niveau 30 - 31.10.00 2 jours Advanced aspects of the C language 2 - 3.11.00 2 days Introduction to Oracle SQL and PL/SQL 13 - 17.11.00 5 days C++ for Particle Physicists 20 - 24.11.00 6 lectures Develop PL/SQL Program Units 20 - 22.11.00 3 days Oracle Application Server Develop Web-Based Applications with PL/SQL 27 - 28.11.00 2 days Programmation TSX Premium 1 28.11 - 1.12.00 4 jours Programmation TSX Premium 2 12 - 15.12.00 4 jours If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : http://www.cern.ch/Training/ or fill in an “application for training” form available from your Divisional Secretariat or from your DTO (Divisional Training Offi...

  10. Places available**

    CERN Multimedia

    Places are available in the following courses: Hands-on Introduction to Python Programming: 11-13.08.2003 (3 days) Introduction to the CERN Engineering Data Management System (EDMS): 26.08.2003 (1 day) The CERN Engineering Data Management System (EDMS) for Engineers: 27.08.2003 (1 day) CLEAN-2002 : Travailler en salle blanche : 4.09.2003 (une demi-journée) AutoCAD 2002 - Level 1: 4, 5, 15, 16.09.2003 (2 x 2 days) AutoCAD Mechanical 6 PowerPack : 17, 18, 25, 26.09.2003 et 2, 3.10.2003 (3 x 2 journées, français) AutoCAD 2002 - niveau 1 : 23, 24, 30.09.2003 et 1.10.2003 (2 x 2 journées) Introduction to the CERN Engineering Data Management System (EDMS): 23.09.2003 (1 day) The CERN Engineering Data Management System (EDMS) for Local Administrators: 24-25.09.2003 (2 days) AutoCAD 2002 - niveau 2 : 8 et 10.10.2003 (2 journées) CLEAN-2002: Working in a Cleanroom: 23.10.2003 (half day, p.m.) ** The number of places available may vary. Please check our Web site to find out the current availabili...

  11. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses: Hands-on Introduction to Python Programming: 11-13.08.2003(3 days) Introduction to the CERN Engineering Data Management System (EDMS): 26.08.2003 (1 day) The CERN Engineering Data Management System (EDMS) for Engineers: 27.08.2003 (1 day) CLEAN-2002 : Travailler en salle blanche : 4.09.2003 (une demi-journée) AutoCAD 2002 - Level 1: 4, 5, 15, 16.09.2003 (2 x 2 days) AutoCAD Mechanical 6 PowerPack : 17, 18, 25, 26.09.2003 et 2, 3.10.2003 (3 x 2 journées, français) AutoCAD 2002 - niveau 1 : 23, 24, 30.09.2003 et 1.10.2003 (2 x 2 journées) Introduction to the CERN Engineering Data Management System (EDMS): 23.09.2003 (1 day) The CERN Engineering Data Management System (EDMS) for Local Administrators: 24-25.09.2003 (2 days) AutoCAD 2002 - niveau 2 : 8 et 10.10.2003 (2 journées) CLEAN-2002: Working in a Cleanroom: 23.10.2003 (half day, p.m.) ** The number of places available may vary. Please ch...

  12. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: LabView Hands-on (bilingue/bilingual - gratuit/free of charge) : 13.9.02 (a.m.) LabView DAQ Hands-on (bilingue/bilingual - gratuit/free of charge) : 13.9.02 (p.m.) AutoCAD 2002 - niveau 1 : 19, 20, 26, 27.9.02 (4 jours) LabView Base 1 : 23 - 25.9.02 (3 jours) LabView DAQ (E) : 26 - 27.9.02 (2 days) AutoCAD Mechanical 6 PowerPack (F) : 30.9, 1, 2, 9, 10, 11.10.02 (6 jours) CLEAN-2002 : Working in a Cleanroom (free of charge) : 10.10.02 (half-day, p.m.) AutoCAD 2002 - niveau 2 : 14 - 15.10.02 (2 jours) AutoCAD 2002 - Level 1 : 17, 18, 24, 25.10.02 (4 days) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : Technical Training or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Of...

  13. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel 74924

    2002-01-01

    Places are available in the following courses: LabView hands-on : 21.01.02 (1/2 journée) LabView DAQ hands-on : 21.01.02 (1/2 journée) FileMaker Pro : 22 - 25.1.02 (4 jours) MS-Project 2000 : 24 & 25.01.02 (2 jours) Introduction au PC et à Windows 2000 au CERN : 29 - 30.1.02 (2 jours) LabView Base 1 : 4 - 6.2.02 (3 jours) LabView DAQ (E) : 7 & 8.02.02 (2 days) Hands-on Object-Oriented Design & Programming with Java : 11 - 13.02.02 (3 days) C++ for Particle Physicists : 11 - 15.3.2002 (6 * 3 hour lectures) Cours sur la migration AutoCAD : AutoCAD : Mise à jour AutoCAD r-14 vers 2002 (2 jours) AutoCAD Mechanical PowerPack 6 basé sur AutoCAD 2002 (5 jours) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : Technical Training or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO ...

  14. PLACES AVAILABLE

    CERN Multimedia

    TECHNICAL TRAINING; Tel. 74460

    2001-01-01

    Places are available in the following courses: MS-Project 1er niveau : 20 - 23.2.01 (4 matins) Architecture d'automatisme : 20 - 21.2.01 (2 jours) Introduction à PowerPoint : 26.2.01 (1 journée) Programmation TSX Premium 1 (Schneider) : 26.2 - 2.3.01 (5 jours) Premiers pas avec votre PC : 27.2 - 2.3.01 (4 matins) C++ for Particle Physicists : 5 - 9.3.01 (6*3 hour lectures) EXCEL : 6, 7 et 13, 14.3.01 (4 jours) The JAVA programming language level 2 :  12 - 14.3.01 (3 days) Nouveautés de FileMaker :  20 - 23.03.01 (4 matins) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt.

  15. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: Habilitation électrique : recyclage HT/BT : 11 - 15.3.2002  (2 * 2 heures) PVSS Basics :  8 - 12.4.02  (5 days) ELEC-2002 : Spring Term :  9, 11, 16, 18, 23, 25, 30.4.02 (7 * 2.5 hours) LabVIEW base 1 : 22 - 24.4.02 (3 jours) LabVIEW DSC (F) 25 & 26.4.02 (2 jours) LabVIEW Basics 2 : 13 & 14.5.02 (2 days) LabVIEW DAQ (F) : 15 & 16.5.02 (2 jours) Cours sur la migration AutoCAD :   AutoCAD : Mise à jour AutoCAD r-14 vers 2002 (2 jours) AutoCAD Mechanical PowerPack 6 basé sur AutoCAD 2002 (5 jours) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : Technical Training or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applica...

  16. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: November 2002   Hands-on Object-Oriented Design and Programming with C++:  19 - 21.11.02  (3 days)  December 2002   LabVIEW - DSC (English) :  2 - 3.12.02  (2 days) AutoCAD 2002 - niveau 2 :  2 & 3.12.02  (2 jours) FileMaker (Français) :  2 - 5.12.02  (4 jours) PCAD Schémas - Débutants :  5 & 6.12.02  (2 jours) PCAD PCB - Débutants :  9 - 11.12.02  (3 jours) FrontPage 2000 - level 1:  9 & 10.12.02  (2 days) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : Technical Training or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisiona...

  17. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: November 2002   Java Programming Language level 1 :  28 & 29.11.02  (2 days) December 2002   LabVIEW - DSC (English) :  2 - 3.12.02  (2 days) FileMaker (Français) :  2 - 5.12.02  (4 jours) PCAD Schémas - Débutants :  5 & 6.12.02  (2 jours) PCAD PCB - Débutants :  9 - 11.12.02  (3 jours) FrontPage 2000 - level 1:  9 & 10.12.02  (2 days) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at : Technical Training or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. Technical Training M...

  18. [Not Available].

    Science.gov (United States)

    Sánchez Sánchez, Fuensanta; Sánchez Marín, Francisco José; López Benavente, Yolanda

    2008-12-01

    To identify the characteristics, needs and difficulties of training of health professionals in health care and inter-professional communication and discover mechanisms for improvement and a desirable educational profile for implementing a training strategy. Qualitative, descriptive and interpretive study carried out between September 2006 and July 2007 at the initiative of the Dirección General de Asistencia Sanitaria-Servicio Murciano de Salud (SMS) and the Dirección General de Calidad Asistencial, Formación e Investigación Sanitaria-Consejería de Sanidad of Murcia, Spain. Participants included 11 doctors, 5 nurses, 1 psychologist and 1 primary and specialised care journalist and the Consejería de Sanidad of Murcia. 2 focus groups were used with sampling by structural saturation, recording of speeches on audiovisual support, verbatim transcript and content analysis. We must encourage attitude changes and acquire the tools for proper care in everyday situations. It is also necessary to rethink subject matter and approaches, define the profile of teachers and develop collaboration and motivation mechanisms. Training in health care communication and inter-professional communication is crucial but it is limited, self-taught, poorly structured and generalistic. It has difficulties associated with attendance, outreach and recognition. A strategic plan for training communication must be based on a human perspective. Its integration must be undertaken by the institution, and universal with the interests and needs felt and expressed by professionals and citizens. Copyright © 2008 Sociedad Española de Calidad Asistencial. Published by Elsevier Espana. All rights reserved.

  19. Characterization and enhanced nonlinear optical limiting response in carbon nanodots dispersed in solid-state hybrid organically modified silica gel glasses

    Science.gov (United States)

    Huang, Li; Zheng, Chan; Guo, Qiaohang; Huang, Dongdong; Wu, Xiukai; Chen, Ling

    2018-02-01

    Freely dispersed carbon nanodots (CNDs) were introduced into a 3-glycidoxy-propyltrimethoxysilane modified silicate gel glass (i.e. an organically modified silica or ORMOSIL) by a highly efficient and simple sol-gel process, which could be easily extended to prepare functional molecules/nanoparticles solid state optoelectronic devices. Scanning electron microscope imaging, Fourier transform infrared spectroscopy, pore structure measurements, ultraviolet-visible spectroscopy, and fluorescence spectroscopy were used to investigate the surface characteristics, structure, texture, and linear optical properties of the CND/SiO2 ORMOSIL gel glasses. Images and UV/Vis spectra confirmed the successful dispersion of CNDs in the ORMOSIL gel glass. The surface characteristics and pore structure of the host SiO2 matrix were markedly changed through the introduction of the CNDs. The linear optical properties of the guest CNDs were also affected by the sol-gel procedure. The nonlinear optical (NLO) properties of the CNDs were investigated by a nanosecond open-aperture Z-scan technique at 532 nm both in liquid and solid matrices. We found that the NLO response of the CNDs was considerably improved after their incorporation into the ORMOSIL gel glasses. Possible enhancement mechanisms were also explored. The nonlinear extinction coefficient gradually increased while the optical limiting (OL) threshold decreased as the CND doping level was increased. This result suggests that the NLO and OL properties of the composite gel glasses can be optimized by tuning the concentration of CNDs in the gel glass matrix. Our findings show that CND/SiO2 ORMOSIL gel glasses are promising candidates for optical limiters to protect sensitive instruments and human eyes from damage caused by high power lasers.

  20. Places available **

    CERN Multimedia

    2003-01-01

    Places are available in the following courses: PIPES-2003 - Pratique du Sertissage de tubes métalliques et multicouches : 26.8.03 (stage pratique) The CERN Engineering Data Management System (EDMS) for Engineers : 27.8.03 (1 day, free of charge) CLEAN-2002 : Travailler en salle blanche : 4.9.03 (une demi-journée, séminaire gratuit) The CERN Engineering Data Management System (EDMS) for Local Administrators : 24 & 25.9.03 (2 days, free of charge) Siemens SIMATIC Training : Programmation STEP7 - niveau 1 : 29 - 2.10.03 (4 jours) - ouverture des inscriptions fin août Programmation STEP7 - niveau 2 : 13 - 17.10.03 (5 jours) - ouverture des inscriptions fin août Réseau Simatic Net : 22 & 23.10.03 (2 jours) - ouverture des inscriptions fin août CLEAN-2002 : Working in a Cleanroom : 23.20.03 (half day, free of charge) These courses will be given in French or Englis...

  1. Places available**

    CERN Document Server

    2003-01-01

    Places are available in the following courses : FrontPage 2000 - niveau 1: 20 & 21.5.03 (2 jours) PIPES-2003 : Pratique du sertissage de tubes métalliques et multicouches: 21.5.03 (1 jour) Introduction à la CAO Cadence: de la saisie de schéma Concept-HDL au PCB : 20 & 22.5.03 (2 jours) AutoCAD Mechanical 6 PowerPack (E): 5, 6, 12, 13, 26, 27.6.03 (6 days) EXCEL 2000 - niveau 1: 10 & 11.6.03 (2 jours) Conception de PCB rapides dans le flot Cadence: 11.6.03 (matin) EXCEL 2000 - level 1: 12 & 13.6.03 (2 days) Introduction to PVSS: 16.6.03 (half-day, pm) Basic PVSS: 17 - 19.6.03 (3 days) Réalisation de PCB rapides dans le flot Cadence: 17.6.03 (matin) LabView DSC (language to be defined): 19 & 20.6.03 PVSS - JCOP Framework Tutorial: 20.6.03 (1 day) EXCEL 2000 - niveau 2: 24 & 25.6.03 (2 jours) Siemens SIMATIC Training: Introduction to STEP7: 3 & 4.6.03 (2 days) STEP7 Programming: 16 - 20.6.03 (5 days) Simatic Net Network: 26 & 27.6.03 (2 days) These courses will be given...

  2. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: Introduction to Oracle 8i : SQL and PL/SQL:  7 - 11.10.02  (5 days) CLEAN-2002 : Working in a Cleanroom (free of charge):  10.10.02  (half-day, p.m.) AutoCAD 2002 - niveau 2 :  14 - 15.10.02  (2 jours) Introduction à DesignSpace :  16.10.02  (1 journée) Introduction to DesignSpace:  17.10.02  (1 day) AutoCAD 2002 - Level 1:  17, 18, 24, 25.10.02  (4 days) AutoCAD Mechanical 6 PowerPack (F) :  21, 22, 23.10 et 4, 5, 6.11.02  (6 jours) Introduction à ANSYS/Introduction to ANSYS (langue à définir suivant demande/ Language to be chosen according to demand):  21 - 25.10.02  (5 jours/days) HREF-2002: Helium Refrigeration Techniques (English-French, bilingual) :  21 - 25.10.2002  (7 half days) HREF-2002: Techniques de la Réfri...

  3. Places available**

    CERN Document Server

    2003-01-01

    Places are available in the following courses : The CERN EDMS for Local Administrators : 24 & 25.9.03 (2 days, free of charge) HeREF-2003 : Techniques de la réfrigération Hélium (cours en français avec support en anglais) : 6 - 10.10.2003 (7 demi-journées) The Java Programming Language Level 1 : 6 - 7.10.2003 (2 days) Java 2 Enterprise Edition - Part 2 : Enterprise JavaBeans : 8 - 10.10.2003 (3 days) FileMaker - niveau 1 : 9 & 10.10.03 (2 jours) EXCEL 2000 - niveau 1 : 20 & 22.10.03 (2 jours) AutoCAD 2002 - niveau 1 : 20, 21, 27, 28.10.03 (4 jours) CLEAN-2002 : Working in a Cleanroom : 23.10.03 (half day, free of charge) AutoCAD 2002 - Level 1 : 3, 4, 12, 13.11.03 (4 days) AutoCAD 2002 - niveau 2 : 10 & 11.11.03 (2 jours) ACCESS 2000 - niveau 1 : 13 & 14.11.03 (2 jours) AutoCAD Mechanical 6 PowerPack (E) : 17, 18, 24, 25.11 & 1, 2.12.03 (6...

  4. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: Introduction à DesignSpace :  16.10.02  (1 journée) AutoCAD Mechanical 6 PowerPack (F) :  21, 22, 23.10 et 4, 5, 6.11.02  (6 jours) Introduction à ANSYS 21 - 25.10.02  (5 jours/days) HREF-2002: Helium Refrigeration Techniques (English-French, bilingual) :  21 - 25.10.2002  (7 half days) LabVIEW Basics 1 (English):  21 - 23.10.02  (3 days) LabVIEW Basics 2 (English):  24 & 25.10.02  (2 days) Oracle 8i : Access the Database with Java:  7 & 8.11.02  (2 days) AutoCAD 2002 - niveau 2 :  7 & 8.11.02  (2 jours) AutoCAD 2002 - Level 1:  14, 15, 21, 22.11.02  (4 days) LabVIEW - Advanced (English) :  18 - 20.11.2002  (3 days) AutoCAD 2002 - niveau 1 :  19, 20, 25, 26.11.02 (4 jours) Oracle iDS Designer: First Class:&...

  5. Places available**

    CERN Document Server

    2003-01-01

    Places are available in the following courses: CLEAN-2002 : Travailler en salle blanche (séminaire gratuit) : 4.9.03 (une demi-journée) The CERN EDMS for Local Administrators (free of charge) : 24 & 25.9.03 (2 days) HeREF-2003 : Techniques de la réfrigération Hélium (cours en français avec support en anglais) : 6 - 10.10.2003 (7 demi-journées) The Java Programming Language Level 1 : 6 - 7.10.2003 (2 days) Java 2 Enterprise Edition - Part 2 : Enterprise JavaBeans : 8 - 10.10.2003 (3 days) FileMaker - niveau 1 : 9 & 10.10.03 (2 jours) EXCEL 2000 - niveau 1 : 20 & 22.10.03 (2 jours) AutoCAD 2002 - niveau 1 : 20, 21, 27, 28.10.03 (4 jours) CLEAN-2002 : Working in a Cleanroom (free of charge) : 23.10.03 (half day) AutoCAD Mechanical 6 PowerPack (E) : 23, 24, 30, 31.10 & 12, 13.11.03 (6 days) AutoCAD 2002 - niveau 2 : 10 & 11.11.03 (2 jours)...

  6. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses: The CERN EDMS for Local Administrators : 24 & 25.9.03 (2 days, free of charge) HeREF-2003 : Techniques de la réfrigération Hélium cours en français avec support en anglais) : 6 - 10.10.2003 (7 demi-journées) The Java Programming Language Level 1 : 6 - 7.10.2003 (2 days) Java 2 Enterprise Edition - Part 2 : Enterprise JavaBeans : 8 - 10.10.2003 (3 days) FileMaker - niveau 1 : 9 & 10.10.03 (2 jours) EXCEL 2000 - niveau 1 : 20 & 22.10.03 (2 jours) AutoCAD 2002 - niveau 1 : 20, 21, 27, 28.10.03 (4 jours) CLEAN-2002 : Working in a Cleanroom : 23.10.03 (half day, free of charge) AutoCAD 2002 - Level 1 : 3, 4, 12, 13.11.03 (4 days) AutoCAD 2002 - niveau 2 : 10 & 11.11.03 (2 jours) ACCESS 2000 - niveau 1 : 13 & 14.11.03 (2 jours) AutoCAD Mechanical 6 PowerPack (E) : 17, 18, 24, 25.11 & 1, 2.12.03 (6 days) FrontPage 2000 - niveau 1 : 20 & 21.11.03 (2 jours) MAGNE-03 : Magnétisme pour l'électrotechnique : 25 - 27.11.03 (3 jours) ...

  7. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: LabView hands-on (bilingue/bilingual): 5.11.02 (matin/morning) LabView DAQ hands-on (bilingue/bilingual):  5.11.02  (après-midi afternoon) Introduction au PC et Windows 2000 au CERN:  6 & 7.11.02  (2 jours) Oracle 8i : Access the Database with Java:  7 & 8.11.02  (2 days) AutoCAD 2002 - niveau 2:  7 & 8.11.02  (2 jours) Introduction to PVSS (free of charge):  11.11.2002 pm  (1/2 day) Basic PVSS:  12 - 14.11.02  (3 days) EXCEL 2000 - niveau 1:  12 & 13.11.02  (2 jours) CLEAN-2002: Working in a Cleanroom (English, free of charge):  13.11.2002  (afternoon) LabView Base 1 :  13 - 15.11.02  (3 jours) AutoCAD 2002 - Level 1:  14, 15, 21, 22.11.2002  (4 days) LabVIEW - Advanced:  18 - 20.11.02  (3 days) Auto...

  8. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses: PIPES-2003 - Pratique du sertissage de tubes métalliques et multicouches :26.8.03(stage pratique) The CERN EDMS for Engineers (free of charge) : 27.8.03 (1 day) CLEAN-2002 : Travailler en salle blanche (séminaire gratuit) : 4.9.03(une demi-journée) The CERN EDMS for Local Administrators (free of charge) : 24 & 25.9.03 (2 days) HeREF-2003 : Techniques de la réfrigération Hélium (cours en français avec support en anglais) : 6 - 10.10.2003 (7 demi-journées) The Java Programming Language Level 1 : 6 - 7.10.2003 (2 days) Java 2 Enterprise Edition - Part 2 : Enterprise JavaBeans : 8 - 10.10.2003 (3 days) FileMaker - niveau 1 : 9 & 10.10.03 (2 jours) EXCEL 2000 - niveau 1 : 20 & 22.10.03 (2 jours) AutoCAD 2002 - niveau 1 : 20, 21, 27, 28.10.03 (4 jours) CLEAN-2002 : Working in a Cleanroom (free of charge) : 23.10.03 (half day) AutoCAD Mechanical 6 PowerPack (E) : 23, 24, 30, 31.10 & 12, 13.11.03 (6 days) AutoCAD 2002 - niveau 2...

  9. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses: The CERN EDMS for Local Administrators (free of charge) : 24 & 25.9.03 (2 days) HeREF-2003 : Techniques de la réfrigération Hélium (cours en français avec support en anglais) : 6 - 10.10.2003 (7 demi-journées) The Java Programming Language Level 1 : 6 - 7.10.2003 (2 days) Java 2 Enterprise Edition - Part 2 : Enterprise JavaBeans : 8 - 10.10.2003 (3 days) FileMaker - niveau 1 : 9 & 10.10.03 (2 jours) EXCEL 2000 - niveau 1 : 20 & 22.10.03 (2 jours) AutoCAD 2002 - niveau 1 : 20, 21, 27, 28.10.03 (4 jours) CLEAN-2002 : Working in a Cleanroom (free of charge) : 23.10.03 (half day) AutoCAD Mechanical 6 PowerPack (E) : 23, 24, 30, 31.10 & 12, 13.11.03 (6 days) AutoCAD 2002 - niveau 2 : 10 & 11.11.03 (2 jours) ACCESS 2000 - niveau 1 : 13 & 14.11.03 (2 jours) FrontPage 2000 - niveau 1 : 20...

  10. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: October 2002   Introduction to the CERN Engineering Data Management System (free of charge):  29.10.2002  (1 day) The CERN EDMS for Advanced users (free of charge):  30.10.2002  (1 day) November 2002   LabView hands-on (bilingue/bilingual): 5.11.02 (matin/morning) LabView DAQ hands-on (bilingue/bilingual):  5.11.02  (après-midi afternoon) Introduction au PC et Windows 2000 au CERN :  6 & 7.11.02  (2 jours) Oracle 8i : Access the Database with Java:  7 & 8.11.02  (2 days) AutoCAD 2002 - niveau 2 :  7 & 8.11.02  (2 jours) Introduction to PVSS (free of charge):  11.11.2002 pm  (1/2 day) Basic PVSS:  12 - 14.11.02  (3 days) EXCEL 2000 - niveau 1 :  12 & 13.11.02  (2 jours) CLEAN-2002: Working in a Cleanroom (English, free ...

  11. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: Introduction to Oracle 8i : SQL and PL/SQL:  7 - 11.10.02  (5 days) CLEAN-2002 : Working in a Cleanroom (free of charge):  10.10.02  (half-day, p.m.) LabView Hands-on (bilingue/bilingual) : 10.10.02 (matin/morning) LabView DAQ Hands-on (bilingue/bilingual)  10.10.02 (après-midi /afternoon) Introduction à DesignSpace :  16.10.02  (1 journée) Introduction to DesignSpace:  17.10.02  (1 day) AutoCAD Mechanical 6 PowerPack (F) :  21, 22, 23.10 et 4, 5, 6.11.02  (6 jours) Introduction à ANSYS/Introduction to ANSYS (langue à définir suivant demande/ Language to be chosen according to demand):  21 - 25.10.02  (5 jours/days) HREF-2002: Helium Refrigeration Techniques (English-French, bilingual) :  21 - 25.10.2002  (7 half days) HREF-2002: Techniques de la...

  12. PLACES AVAILABLE

    CERN Multimedia

    Enseignement Technique; Tél. 74924; Technical Training; Monique Duval; Tel. 74924

    2000-01-01

    Places are available in the following courses : Premiers pas avec votre PC 12 - 15.9.00 (4 demi-journées) WORD 20, 21 et 26, 27.9.2000 (4 jours) JAVA programming level 1 25 - 26.9.2000 (2 days) Gaz inflammables 1 26.9.2000 (1 journée) Advanced aspects of PERL 5 6.10.2000 (1 day) Initiation au WWW 10 - 12.10.00 (3 demi-journées) WORD : importer et manipuler des images 16.10.2000 (1 journée) FileMaker 17, 18 et 24, 25.10.00 (4 jours) Nouveautés de WORD 19 et 20.10.2000 (2 jours) ACCESS 1er niveau 30 - 31.10.00 (2 jours)Introduction à PowerPoint 6.11.00 (1 journée)Nouveautés d’EXCEL 7.11.2000(4 demi-journées)Excel 13, 14 et 20, 21.11.00 (4 jours) LabView hands-on 13.11.2000(4 hours)LabView Basics 1 14 - 16.11.2000 (3 days) MS-Project 1er niveau 14-17.11.00 (4 demi-journées) If you wish to participate in one of these courses, please discuss with your supervisor and apply elec...

  13. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2002-01-01

    Places are available in the following courses: LabView hands-on : 21.01.02 (1/2 journée) LabView DAQ hands-on : 21.01.02 (1/2 journée) FileMaker Pro : 22 - 25.1.02 (4 jours) MS-Project 2000 : 22, 24 & 25.01.02 (3 jours) Introduction au PC et à Windows 2000 au CERN : 29 - 30.1.02 (2 jours) LabView Base 1 : 4 - 6.2.02 (3 jours) LabView DAQ  (E) :  7 & 8.02.02 (2 days) Hands-on Object-Oriented Design & Programming with Java :  11 - 13.02.02 (3 days) PVSS basics :  11 - 15.2.02 (5 days) Introduction à Windows 2000 : 18.2.02 (1 demi-journée) Introduction to the CERN Engineering Data Management System :  20.2.02 (1 day) The CERN Engineering Data Management System for Advanced users :  21.2.02  (1 day) C++ for Particle Physicists :  11 - 15.3.2002  (6 * 3 hour lectures) Cours sur la migration AutoCAD : AutoCAD : Mise à...

  14. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: LabVIEW - Basics 1 :  10 - 12.12.01 (3 days) Introduction to XML :  12 & 13.12.01 (2 days) Introduction au PC et Windows 2000 : 12 & 14.12.01 (2 jours) LabVIEW - Basics 2 :  13 - 14.12.01 (2 days) Habilitation électrique : superviseurs : 17.12.2001 (1/2 journée) MS-Project 2000 : 10 & 11.01.02 (2 jours) EXCEL 2000 - niveau 2 : 15 - 16.1.02 (2 jours) Sécurité dans les installations cryogéniques: 15-17.1.2002 (2 demi-journées) C++ Programming Level 2 - Traps and Pitfalls :  15 - 18.1.2002  (4 days) ELEC-2002 Winter Term: Readout and system electronics for Physics  15.1.2002 - 7.2.2002 (8 half- days) Nouveautés de WORD 2000 : 18.1.02 (1/2 journée) LabView hands-on : 21.01.02 (1/2 journée) LabView DAQ hands-on : 21.01.02 (1/2 journée) FileMaker Pro : 22 -...

  15. PLACES AVAILABLE

    CERN Multimedia

    Enseignement Technique; Tel. 74924

    2001-01-01

    Places are available in the following courses: MS-Project 2000 : 10 & 11.01.02 (2 jours) EXCEL 2000 - niveau 2 : 15 - 16.1.02 (2 jours) Sécurité dans les installations cryogéniques: 15-17.1.2002 (2 demi-journées) C++ Programming Level 2 - Traps and Pitfalls :  15 - 18.1.2002  (4 days) ELEC-2002 Winter Term: Readout and system electronics for Physics  15.1.2002 - 7.2.2002 (8 half- days) Nouveautés de WORD 2000 : 18.1.02 (1/2 journée) LabView hands-on : 21.01.02 (1/2 journée) LabView DAQ hands-on : 21.01.02 (1/2 journée) FileMaker Pro : 22 - 25.1.02 (4 jours) MS-Project 2000 : 24 & 25.01.02 (2 jours) Introduction au PC et à Windows 2000 au CERN : 29 - 30.1.02 (2 jours) LabView Base 1 : 4 - 6.2.02 (3 jours) LabView DAQ  (E) :  7 & 8.02.02 (2 days) Hands-on Object-Oriented Design & Programming with Java :&nbs...

  16. Places available **

    CERN Multimedia

    2003-01-01

    Des places sont disponibles dans les cours suivants : Places are available in the following courses : WorldFIP 2003 pour utilisateurs : 11-14.2.03 (4 jours) DISP-2003 ? Spring I Term : Introduction to Digital Signal Processing : 20, 27.2, 6, 13, 20, 27.3, 3.4.03 (7 X 2-hour lectures) AXEL-2003 - Introduction to Accelerators : 24-28.2.03 (10 X 1-hour lectures) AutoCAD 2002 - niveau 1 : 24, 25.2 & 3, 4.3.03 (4 jours) Introduction à Windows 2000 au CERN : 25.2.03 (1/2 journée) LabView base 2/LabView Basics 2 : 10 & 11.3.03 (2 jours/2 days) langue à définir/Language to be decided C++ for Particle Physicists : 10 ? 14.3.03 (6 X 3-hour lectures) Introduction to PVSS : 10.3.03 (half day, afternoon) Basic PVSS : 11 - 13.3.03 (3 days) LabView avancé /LabView Advanced : 12 - 14.3.03 (3 jours/3days) Langue à définir/language to be decided AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 17, 18, 24 & 25.3.03 (6 jours) PVSS - JCOP Framework Tutorial : 14.3.03 (1 day) MAGNE-03 - Magnetism for Technical Ele...

  17. Places available **

    CERN Multimedia

    2003-01-01

    Des places sont disponibles dans les cours suivants : Places are available in the following courses : Introduction à Windows 2000 au CERN : 25.2.03 (1/2 journée) LabView base 2/LabView Basics 2 : 10 & 11.3.03 (2 jours/2 days) langue à définir/Language to be decided C++ for Particle Physicists : 10 - 14.3.03 (6 X 3-hour lectures) Introduction to PVSS : 10.3.03 (half day, afternoon) Basic PVSS : 11 - 13.3.03 (3 days) LabView avancé /LabView Advanced : 12 - 14.3.03 (3 jours/3days) Langue à définir/Language to be decided AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 17, 18, 24 & 25.3.03 (6 jours) PVSS - JCOP Framework Tutorial : 14.3.03 (1 day) CLEAN-2002 : Working in a cleanroom : 2.4.03 (half-day, afternoon, free course, registration required) LabView base 1/LabView Basics 1 : 9 - 11.4.03 (3 jours/3 days) Langue à définir/Language to be decided DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures) AutoCAD 2002 - niveau 2 : 5 & 6.5.03 (...

  18. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : CLEAN-2002 : Working in a cleanroom (free course, registration required) : 2.4.03 (half-day, afternoon) LabView base 1/LabView Basics 1 (Langue à définir/ language to be decided) : 9 - 11.4.03 (3 jours/3 days) DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures) AutoCAD 2002 - niveau 1 : 29, 30.4 et 7, 8.5.03 (4 jours) AutoCAD 2002 - niveau 2 : 5 & 6.5.03 (2 jours) AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 20, 21, 27 & 28.5.03(6 jours) Formation Siemens SIMATIC /Siemens SIMATIC Training : Introduction à STEP7 /Introduction to STEP7 : 3 & 4.6.03 (2 jours/2 days) Programmation STEP7/STEP7 Programming : 31.3 - 4.4.03 / 16 - 20.6.03 (5 jours/5 days) Réseau Simatic Net /Simatic Net Network : 15 & 16.4.03 / 26 & 27.6.03 These courses will be given in French or English following the requests. Cours de sécurité : Etre TSO au CERN : 3 sessions sont programmées pour 2003 : 25...

  19. Places available **

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : CLEAN-2002 : Working in a cleanroom (free course, registration required): 11.4.03 (half-day, afternoon, ) LabView Basics 2 : 10 - 11.4.03 (3 days) DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures) AutoCAD 2002 - niveau 1 : 29, 30.4 et 7, 8.5.03 (4 jours) Oracle iDS Reports : Build Internet Reports : 5 - 9.5.03 (5 days) AutoCAD 2002 - niveau 2 : 5 & 6.5.03 (2 jours) AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 20, 21, 27 & 28.5.03 (6 jours) Formation Siemens SIMATIC /Siemens SIMATIC Training : Introduction à STEP7 /Introduction to STEP7 : 3 & 4.6.03 (2 jours/2 days) Programmation STEP7/STEP7 Programming : 31.3 - 4.4.03 / 16 - 20.6.03 (5 jours/5 days) Réseau Simatic Net /Simatic Net Network : 15 & 16.4.03 / 26 & 27.6.03 These courses will be given in French or English following the requests. Cours de sécurité : Etre TSO au CERN : Prochaines sessions : 24, 25 & 27.6....

  20. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures) Oracle iDS Reports : Build Internet Reports : 5 - 9.5.03 (5 days) LabView DAQ (language to be defined) : 8 & 9.5.03 AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 20, 21, 27 & 28.5.03 (6 jours) AutoCAD 2002 - niveau 2 : 3 & 4.6.03 (2 jours) LabView DSC (language to be defined) : 19 & 20.6.03 Siemens SIMATIC Training : Introduction to STEP7 : 3 & 4.6.03 (2 days) STEP7 Programming : 16 - 20.6.03 (5 days) Simatic Net Network : 15 & 16.4.03 / 26 & 27.6.03 (sessions of 2 days) These courses will be given in French or English following the requests. Cours de sécurité : Etre TSO au CERN : Prochaines sessions : 24, 25 & 27.6.03 - 4, 5 & 7.11.03 (session de 3 jours) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the course description ...

  1. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : CLEAN-2002 : Working in a cleanroom (free course, registration required): 11.4.03 (half-day, afternoon, ) LabView Basics 2 : 10 - 11.4.03 (3 days) DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures) AutoCAD 2002 - niveau 1 : 29, 30.4 et 7, 8.5.03 (4 jours) Oracle iDS Reports : Build Internet Reports : 5 - 9.5.03 (5 days) AutoCAD 2002 - niveau 2 : 5 & 6.5.03 (2 jours) AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 20, 21, 27 & 28.5.03(6 jours) Formation Siemens SIMATIC /Siemens SIMATIC Training : Introduction à STEP7 /Introduction to STEP7 : 3 & 4.6.03 (2 jours/2 days) Programmation STEP7/STEP7 Programming : 31.3 - 4.4.03 / 16 - 20.6.03 (5 jours/5 days) Réseau Simatic Net /Simatic Net Network : 15 & 16.4.03 / 26 & 27.6.03 These courses will be given in French or English following the requests. Cours de sécurité : Etre TSO au CERN : Prochaines sessions : 24, 25 & 27.6...

  2. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures) Programmation de pilotes périphériques : 5 - 8.5.03 (4 jours) Oracle iDS Reports : Build Internet Reports : 5 - 9.5.03 (5 days) LabView DAQ (language to be defined) : 8 & 9.5.03 AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 20, 21, 27 & 28.5.0 (6 jours) FrontPage 2000 - niveau 1 : 20 & 21.5.03 (2 jours) AutoCAD 2002 - niveau 2 : 3 & 4.6.03 (2 jours) EXCEL 2000 - niveau 1 : 10 & 11.6.03 (2 jours) EXCEL 2000 - level 1 : 12 & 13.6.03 (2 days) PowerPoint 2000 (F) : 17 & 18.6.03 (2 jours) FrontPage 2000 - niveau 2 : 19 & 20.6.03 (2 jours) LabView DSC (langue à décider/language to be defined) : 19 & 20.6.03 EXCEL 2000 - niveau 2 : 24 & 25.6.03 (2 jours) Siemens SIMATIC Training : Introduction to STEP7 : 3 & 4.6.03 (2 days) STEP7 Programming : 16 - 20.6.03 (5 days) Simatic Net Network : 26 & 27.6.03 ...

  3. Places available **

    CERN Multimedia

    2003-01-01

    Des places sont disponibles dans les cours suivants : Places are available in the following courses : DISP-2003 - Spring I Term : Introduction to Digital Signal Processing : 20, 27.2, 6, 13, 20, 27.3, 3.4.03 (7 X 2-hour lectures) AXEL-2003 - Introduction to Accelerators : 24 - 28.2.03 (10 X 1-hour lectures) AutoCAD 2002 - niveau 1 : 24, 25.2 & 3, 4.3.03 (4 jours) Introduction à Windows 2000 au CERN : 25.2.03 (1/2 journée) LabView base 2/LabView Basics 2 : 10 & 11.3.03 (2 jours/2 days) langue à définir/Language to be decided C++ for Particle Physicists : 10 - 14.3.03 (6 X 3-hour lectures) Introduction to PVSS : 10.3.03 (half day, afternoon) Basic PVSS : 11 - 13.3.03 (3 days) LabView avancé /LabView Advanced : 12 - 14.3.03 (3 jours/3days) Langue à définir/language to be decided AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 17, 18, 24 & 25.3.03 (6 jours) PVSS - JCOP Framework Tutorial : 14.3.03 (1 day) CLEAN-2002 : Working in a cleanroom : 2.4.03 (half-day, afternoon, free course, regis...

  4. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : CLEAN-2002 : Working in a cleanroom (free course, registration required): 11.4.03 (half-day, afternoon) LabView Basics 2 : 10 - 11.4.03 (3 days) DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures) AutoCAD 2002 - niveau 1 : 29, 30.4 et 7, 8.5.03 (4 jours) Oracle iDS Reports : Build Internet Reports : 5 - 9.5.03 (5 days) AutoCAD 2002 - niveau 2 : 5 & 6.5.03 (2 jours) AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 20, 21, 27 & 28.5.03(6 jours) Formation Siemens SIMATIC /Siemens SIMATIC Training : Introduction à STEP7 /Introduction to STEP7 : 3 & 4.6.03 (2 jours/2 days) Programmation STEP7/STEP7 Programming : 16 - 20.6.03 (5 jours/5 days) Réseau Simatic Net /Simatic Net Network : 15 & 16.4.03 / 26 & 27.6.03 These courses will be given in French or English following the requests. Cours de sécurité : Etre TSO au CERN : Prochaines sessions : 24, 25 & 27.6.03 - 4, 5 & 7....

  5. Places available **

    CERN Multimedia

    2003-01-01

    Des places sont disponibles dans les cours suivants : Places are available in the following courses : C++ for Particle Physicists : 10 - 14.3.03 (6 X 3-hour lectures) Introduction to PVSS : 10.3.03 (half day, afternoon) Basic PVSS : 11 - 13.3.03 (3 days) PVSS - JCOP Framework Tutorial : 14.3.03 (1 day) CLEAN-2002 : Working in a cleanroom : 2.4.03 (half-day, afternoon, free course, registration required) LabView base 1/LabView Basics 1 : 9 - 11.4.03 (3 jours/3 days) Langue à définir/language to be decided DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures) AutoCAD 2002 - niveau 1 : 29, 30.4 et 7, 8.5.03 (4 jours) AutoCAD 2002 - niveau 2 : 5 & 6.5.03 (2 jours) AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 20, 21, 27 & 28.5.03 (6 jours) Formation Siemens SIMATIC /Siemens SIMATIC Training : Introduction à STEP7 /Introduction to STEP7 : 11 & 12.3.03 / 3 & 4.6.03 (2 jours/2 days) Programmation STEP7/STEP7 Programming : 31.3 - 4.4.03 / 16...

  6. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : Introduction to PVSS : 10.3.03 (half-day, afternoon) CLEAN-2002 : Working in a cleanroom : 2.4.03 (half-day, afternoon, free course, registration required) LabView Basics 1 : 9 - 11.4.03 (3 days) Language to be decided. DISP-2003 - Spring II Term : Advanced Digital Signal Processing : 30.4, 7, 14, 21.5.03 (4 X 2-hour lectures). AutoCAD 2002 - niveau 1 : 29, 30.4 et 7, 8.5.03 (4 jours) AutoCAD 2002 - niveau 2 : 5 & 6.5.03 (2 jours) AutoCAD Mechanical 6 PowerPack (F) : 12, 13, 20, 21, 27 & 28.5.03 (6 jours) Siemens SIMATIC Training: Introduction to STEP7 : 3 & 4.6.03 (2 days) STEP7 Programming : 31.3 - 4.4.03 / 16 - 20.6.03 (5 days) Simatic Net Network : 15 & 16.4.03 / 26 & 27.6.03 These courses will be given in French or English following the requests. Cours de sécurité: Etre TSO au CERN : 3 sessions sont programmées pour 2003 : 25, 26 & 28.3.03 - 24, 25 & 27.6.03 - 4, 5 & 7.11.03 (sessions de 3 jours) ** The number o...

  7. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: November 2002   Introduction to PVSS (free of charge): 11.11.02  (afternoon) EXCEL 2000 - niveau 1 :  12 & 13.11.02  (2 jours) CLEAN-2002: Working in a Cleanroom (English, free of charge):  13.11.2002  (afternoon) AutoCAD 2002 - niveau 1 :  14, 15, 21, 22.11.02  (4 jours) Hands-on Object-Oriented Design and Programming with C++:  19 - 21.11.02  (3 days)  EXCEL 2000 - niveau 2 :  25 & 26.11.02  (2 jours) FrontPage 2000 - niveau 1 :  27 & 28.11.02  (2 jours) December 2002   LabVIEW - DSC (English) :  2 - 3.12.02  (2 days) AutoCAD 2002 - niveau 2 :  2 & 3.12.02  (2 jours) FileMaker (Français) :  2 - 5.12.02  (4 jours) PCAD Schémas - Débutants :  5 & 6.12.02 ...

  8. PLACES AVAILABLE

    CERN Multimedia

    Technical training; Tel. 74924

    2001-01-01

    Places are available in the following courses: PROFIBUS : 25 - 26.9.01 (2 jours) PROFIBUS : 27 - 28.9.01 (2 days) Automates et réseaux de terrain : 3 - 4.10.2001 (2 jours) PCAD Schémas - débutants : 4 - 5.10.01 (2 jours) PCAD PCB - débutants : 8 - 10.10.01 (3 jours) Programmation TSX Premium 1 : 15 - 19.10.01 (5 jours) Programmation TSX Premium 1 : 22 - 26.10.01 (5 jours) Programming TSX Premium 2: 19 - 23.11.01 (5 days) Programmation TSX Premium 2 : 26 - 30.11.01 (5 jours) Autocad Migration support courses: a detailed calendar will be published shortly for this series of sessions which will start on 15.10.2001. Registration is already open AutoCAD : Mise à jour AutoCAD r-14 vers 2002 (2 jours) AutoCAD Mechanical PowerPack 6 basé sur AutoCAD 2002 (5 jours) The following LabView courses will be given in either English or French according to demand LabVIEW - Base 1 / LabVIEW - Basics 1 : 10 - 12.9.01 (3 jours / 3 days)...

  9. PLACES AVAILABLES

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: PVSS Basics : 20 - 24.8.01 (5 days) PROFIBUS : 25 - 26.9.01 (2 jours) PROFIBUS : 27 - 28.9.01 (2 days) PCAD Schémas - débutants : 4 - 5.10.01 (2 jours) PCAD PCB - débutants : 8 - 10.10.01 (3 jours) Programming TSX Premium 1: 15 - 19.10.01 (5 days) Programmation TSX Premium 1 : 22 - 26.10.01 (5 jours) Programming TSX Premium 2: 19 - 23.11.01 (5 days) Programmation TSX Premium 2 : 26 - 30.11.01 (5 jours) The following LabView courses will be given in either English or French according to demand LabVIEW - Base 1 / LabVIEW - Basics 1 : 10 - 12.9.01 (3 jours / 3 days) LabVIEW - DAQ / LabVIEW - DAQ : 13 - 14.9.01 (2 jours / 2 days) LabVIEW - Base 1 / LabVIEW - Basics 1 : 15 - 17.10.01 (3 jours / 3 days) LabVIEW - Base 2 / LabVIEW - Basics 2 : 18 - 19.10.01 (2 jours / 2 days) LabVIEW - Base 1 / LabVIEW - Basics 1 : 12 - 14.11.01 (3 jours / 3 days) LabVIEW - DAQ / LabVIEW - DAQ : 15 - 16.11.01 (2 jours / 2...

  10. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: November 2002   LabView hands-on (bilingue/bilingual): 5.11.02 (matin/morning) LabView DAQ hands-on (bilingue/bilingual):  5.11.02  (après-midi afternoon) PCAD Schémas - Débutants :  5 & 6.11.02  (2 jours) PCAD PCB - Débutants :  9 - 11.11.02  (3 jours) Introduction au PC et Windows 2000 au CERN :  6 & 7.11.02  (2 jours) Oracle 8i : Access the Database with Java :  7 & 8.11.02  (2 days) Introduction to PVSS (free of charge):  11.11.2002 pm  (1/2 day) Basic PVSS:  12 - 14.11.02  (3 days) EXCEL 2000 - niveau 1 :  12 & 13.11.02  (2 jours) CLEAN-2002: Working in a Cleanroom (English, free of charge):  13.11.2002  (afternoon) LabView Base 1 :  13 - 15.11.02  (3 jours) AutoCAD 2002 - niveau 1 :  14, 15, 21, 22.11.02  (4 jours) LabVIEW - Advanced:  18 - 20.11.02  (3 days) Hands-on Object-Oriented Design and Programming with C++ :  19 - 21.11.02  (3 days)  LabVIEW - Basics 2:  21 - 22.11.02 ...

  11. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : EXCEL 2000 - niveau 1 : 10 & 11.6.03 (2 jours) Conception de PCB rapides dans le flot Cadence : 11.6.03 (matin) EXCEL 2000 - level 1 : 12 & 13.6.03 (2 days) Introduction to PVSS : 16.6.03 (p.m.) Basic PVSS : 17 - 19.6.03 (3 days) Réalisation de PCB rapides dans le flot Cadence : 17.6.03 (matin) PVSS - JCOP Framework Tutorial : 20.6.03 (1 day) EXCEL 2000 - niveau 2 : 24 & 25.6.03 (2 jours) Siemens SIMATIC Training : Introduction to STEP7 : 3 & 4.6.03 (2 jours/2 days) STEP7 Programming : 16 - 20.6.03 (5 jours/5 days) Simatic Net Network : 26 & 27.6.03 (2 jours/2 days) These courses will be given in French or English following the requests. Programmation automate Schneider : Programmation automate Schneider TSX Premium - 1er niveau : 10 - 13.6.03 (4 jours) - audience : toute personne qui veux maitriser la msie en uvre et la programmation d'un automate TSX Premium - objectifs : maitriser la mise en uvre et la programmation d'un autom...

  12. Places available**

    CERN Multimedia

    2003-01-01

    Places are available in the following courses : FrontPage 2000 - niveau 1 : 20 & 21.5.03 (2 jours) PIPES-2003 : Pratique du sertissage de tubes métalliques et multicouches : 21.5.03 (1 jour) Introduction à la CAO Cadence : de la saisie de schéma Concept-HDL au PCB : 20 & 22.5.03 (2 jours) AutoCAD 2002 - niveau 2 : 3 & 4.6.03 (2 jours) AutoCAD Mechanical 6 PowerPack (F) : 5, 6, 12, 13, 26, 27.6.03 (6 jours) EXCEL 2000 - niveau 1 : 10 & 11.6.03 (2 jours) Conception de PCB rapides dans le flot Cadence : 11.6.03 (matin) EXCEL 2000 - level 1 : 12 & 13.6.03 (2 days) PowerPoint 2000 (F) : 17 & 18.6.03 (2 jours) Réalisation de PCB rapides dans le flot Cadence : 17.6.03 (matin) FrontPage 2000 - niveau 2 : 19 & 20.6.03 (2 jours) LabView DSC (langue à décider/language to be defined) : 19 & 20.6.03 EXCEL 2000 - niveau 2 : 24 & 25.6.03 (2 jours) Siemens SIMATIC Training: Introduction to STEP7 : 3 & 4.6.03 (2 days) STEP7 Programming : 16 - 20.6.03 (5 days) Simatic...

  13. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: PVSS Basics : 20 - 24.8.01 (5 days) PROFIBUS : 25 - 26.9.01 (2 jours) PROFIBUS : 27 - 28.9.01 (2 days) PCAD Schémas - débutants : 4 - 5.10.01 (2 jours) PCAD PCB - débutants : 8 - 10.10.01 (3 jours) Programming TSX Premium 1: 15 - 19.10.01 (5 days) Programmation TSX Premium 1 : 22 - 26.10.01 (5 jours) Programming TSX Premium 2: 19 - 23.11.01 (5 days) Programmation TSX Premium 2 : 26 - 30.11.01 (5 jours) The following LabView courses will be given in either English or French according to demand LabVIEW - Base 1 / LabVIEW - Basics 1 : 10 - 12.9.01 (3 jours / 3 days) LabVIEW - DAQ / LabVIEW - DAQ : 13 - 14.9.01 (2 jours / 2 days) LabVIEW - Base 1 / LabVIEW - Basics 1 : 15 - 17.10.01 (3 jours / 3 days) LabVIEW - Base 2 / LabVIEW - Basics 2 : 18 - 19.10.01 (2 jours / 2 days) LabVIEW - Base 1 / LabVIEW - Basics 1 : 12 - 14.11.01 (3 jours / 3 days) LabVIEW - DAQ / LabVIEW - DAQ : 15 - 16.11.01 (2 jours / 2...

  14. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Introduction à Windows 2000 au CERN : 2 sessions de _ journée les 24 et 25.9.01 PROFIBUS : 25 - 26.9.01 (2 jours) PROFIBUS : 27 - 28.9.01 (2 days) PowerPoint 2000 : 1 et 2.10.01 (2 jours) EXCEL 2000 - niveau 1 : 3 et 4.10.01 (2 jours) Automates et réseaux de terrain : 3 - 4.10.2001 (2 jours) PCAD Schémas - débutants : 4 - 5.10.01 (2 jours) Introduction à Outlook : 5.10.01 (1 journée) Frontpage 2000 - niveau 1 : 8 et 9.10.01 (2 jours) PCAD PCB - débutants : 8 - 10.10.01 (3 jours) C++ for Particle Physicists : 8 - 12.10.01 (6 3-hour lectures) MS-Project 2000 - niveau 1 : 15 - 18.10.01 (4 demi-journées) LabView Basics 1 :  15 - 17.10.01  (3 days) Programmation TSX Premium 1 : 15 - 19.10.01 (5 jours) WORD 2000 : importer et manipuler des images : 19.10.01 (1 journée) Programmation TSX Premium 1 : 22 - 26.10.01...

  15. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Cadence Board Design tools : Upgrading to release 14 :  3 1-day sessions on 9, 10 & 11.10.01 MS-Project 2000 - niveau 1 : 15 - 18.10.01 (4 demi-journées) LabView Base 2 : 18 & 19.10.01 (2 jours) WORD 2000 : importer et manipuler des images : 19.10.01 (1 journée) Contract Follow-up (F) :  30.10.01 (1/2 journée) The CERN Engineering Data Management System for Electronics Design :  30.10.01 (1 day) UNIX pour non-programmeurs : 5 - 7.11.01 (3 jours) The Java programming language Level 1: 8 - 9.11.01 (2 days) LabView Base 1 : 12 - 14.11.01 (3 jours) Introduction to PERL 5 :  15 - 16.11.01  (2 days) Introduction to XML :  19 - 20.11.01 (2 days) Programming TSX Premium 1 :  19 - 23.11.01  (5 days) Introduction to C Programming :  21- 23.11.01 (3 days) The Java programming language Level 2:  26 - 28.11.01 (...

  16. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Introduction à Windows 2000 au CERN : 2 sessions de _ journée les 24 et 25.9.01 PROFIBUS : 25 - 26.9.01 (2 jours) PROFIBUS : 27 - 28.9.01 (2 days) EXCEL 2000 - niveau 1 : 3 et 4.10.01 (2 jours) Automates et réseaux de terrain : 3 - 4.10.2001 (2 jours) Introduction à Outlook : 5.10.01 (1 journée) Frontpage 2000 - niveau 1 : 8 et 9.10.01 (2 jours) C++ for Particle Physicists : 8 - 12.10.01 (6 lectures) MS-Project 2000 - niveau 1 : 15 - 18.10.01 (4 demi-journées) Programmation TSX Premium 1 : 15 - 19.10.01 (5 jours) WORD 2000 : importer et manipuler des images : 19.10.01 (1 journée) Programmation TSX Premium 1 : 22 - 26.10.01 (5 jours) UNIX pour non-programmeurs : 5 - 7.11.01 (3 jours) The Java programming language Level 1: 8 - 9.11.01 (2 days) Introduction to PERL 5 :  15 - 16.11.01  (2 days) Introduction to XML :  19 - 20.11.01 (2...

  17. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: EXCEL 2000 - niveau 1 : 3 et 4.10.01 (2 jours) Automates et réseaux de terrain : 3 - 4.10.2001 (2 jours) Introduction à Outlook : 5.10.01 (1 journée) C++ for Particle Physicists : 8 - 12.10.01 (6 lectures) Cadence Board Design tools : Upgrading to release 14 : 3 1-day sessions on 9, 10 & 11.10.01 MS-Project 2000 - niveau 1 : 15 - 18.10.01 (4 demi-journées) LabView Base 2 : 18 & 19.10.01 (2 jours) WORD 2000 : importer et manipuler des images : 19.10.01 (1 journée) The CERN Engineering Data Management System for Electronics Design :  30.10.01 (1 day) UNIX pour non-programmeurs : 5 - 7.11.01 (3 jours) The Java programming language Level 1: 8 - 9.11.01 (2 days) Introduction to PERL 5 :  15 - 16.11.01  (2 days) Introduction to XML :  19 - 20.11.01 (2 days) Programming TSX Premium 1 :  19 - 23.11.01  (5 days) Introd...

  18. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: MS-Project 2000 - niveau 1 : 15 - 18.10.01 (4 demi-journées) LabView Base 2 : 18 & 19.10.01 (2 jours) WORD 2000 : importer et manipuler des images : 19.10.01 (1 journée) Contract Follow-up (F) : 30.10.01 (1/2 journée) The CERN Engineering Data Management System for Electronics Design :  30.10.01 (1 day) UNIX pour non-programmeurs : 5 - 7.11.01 (3 jours) The Java programming language Level 1: 8 - 9.11.01 (2 days) LabView Base 1 : 12 - 14.11.01 (3 jours) Automates et réseaux de terrain : 13 & 14.11.01 (2 jours) Introduction to PERL 5 :  15 - 16.11.01  (2 days) Introduction to XML :  19 - 20.11.01 (2 days) Programming TSX Premium 1 :  19 - 23.11.01  (5 days) Introduction to C Programming :  21- 23.11.01 (3 days) The Java programming language Level 2:  26 - 28.11.01 (3 days) Programmation TSX Premium 2 : 26 ...

  19. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: LabView Base 1 :  23 - 25.9.02  (3 jours) Object-Oriented Analysis & Design using UML:  25 - 27.9.02  (3 days) LabView DAQ (E):  26 - 27.9.02  (2 days) Introduction to Oracle 8i : SQL and PL/SQL:  7 - 11.10.02  (5 days) CLEAN-2002 : Working in a Cleanroom (free of charge):  10.10.02  (half-day, p.m.) AutoCAD 2002 - niveau 2 :  14 - 15.10.02  (2 jours) Introduction à DesignSpace :  16.10.02  (1 journée) Introduction to DesignSpace:  17.10.02  (1 day) AutoCAD 2002 - Level 1:  17, 18, 24, 25.10.02  (4 days) AutoCAD Mechanical 6 PowerPack (F) :  21, 22, 23.10 et 4, 5, 6.11.02  (6 jours) Introduction à ANSYS/Introduction to ANSYS (langue à définir suivant demande/ Language to be chosen according to demand):...

  20. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: Java 2 Enterprise Edition - Part 2: Enterprise JavaBeans:  18 - 20.9.02  (3 days) AutoCAD 2002 - niveau 1 :  19, 20, 26, 27.9.02  (4 jours) LabView Base 1 :  23 - 25.9.02  (3 jours) Object-Oriented Analysis & Design using UML:  25 - 27.9.02  (3 days) LabView DAQ (E):  26 - 27.9.02  (2 days) Introduction to Oracle 8i : SQL and PL/SQL:  7 - 11.10.02  (5 days) CLEAN-2002 : Working in a Cleanroom (free of charge):  10.10.02  (half-day, p.m.) AutoCAD 2002 - niveau 2 :  14 - 15.10.02  (2 jours) Introduction à DesignSpace :  16.10.02  (1 journée) Introduction to DesignSpace:  17.10.02  (1 day) AutoCAD 2002 - Level 1:  17, 18, 24, 25.10.02  (4 days) AutoCAD Mechanical 6 PowerPack (F) :  21, 22, 23.10 et 4, 5, 6.11....

  1. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Automates et réseaux de terrain : 13 & 14.11.01 (3 jours) Introduction à Windows 2000 au CERN : 12 - 14.11.01 (1/2 journée) Introduction to Windows 2000 at CERN :  14.11.01  (half-day) Introduction to PERL 5 :  15 - 16.11.01  (2 days) Sécurité dans les installations cryogéniques : 21 - 22.11.2001 (2 demi-journées) Introduction to C Programming :  21- 23.11.01 (3 days) Programmation TSX Premium 2 : 26 - 30.11.01 (5 jours) Contract Follow-up (F) : 26.11.01 (1/2 journée) Object-Oriented Analysis and Design :  27 - 30.11.2001  (4 days) Introduction to the CERN Engineering Data Management System :  30.11.2001 (1 day) Electromagnetic Compatibility (EMC): Introduction (bilingual) :  3.12.01 (half-day) Introduction to the CERN Engineering Data Management System : 07.12.2001...

  2. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Contract Follow-up (F) : 30.10.01 (1/2 journée) The CERN Engineering Data Management System for Electronics Design :  30.10.01 (1 day) UNIX pour non-programmeurs : 5 - 7.11.01 (3 jours) Nouveautés d'EXCEL : 5.11.01 (1/2 journée) Introduction a Windows 2000 au CERN : 6.11.01 (1/2 journée) The Java programming language Level 1: 8 - 9.11.01 (2 days) LabView Base 1 : 12 - 14.11.01 (3 jours) Automates et réseaux de terrain : 13 & 14.11.01 (2 jours) Introduction to PERL 5 :  15 - 16.11.01  (2 days) Introduction to XML :  19 - 20.11.01 (2 days) Programming TSX Premium 1 :  19 - 23.11.01  (5 days) Introduction to C Programming :  21- 23.11.01 (3 days) The Java programming language Level 2:  26 - 28.11.01 (3 days) Programmation TSX Premium 2 : 26 - 30.11.01 (5 jours) Autocad Migration support courses: a detail...

  3. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Contract Follow-up (F) : 30.10.01 (1/2 journée) The CERN Engineering Data Management System for Electronics Design :  30.10.01 (1 day) Nouveautés d'Excel 2000 : 5.11.01 (1/2 journée) UNIX pour non-programmeurs : 5 - 7.11.01 (3 jours) Introduction à Windows 2000 au CERN : 6.11.01 (1/2 journée) The Java programming language Level 1: 8 - 9.11.01 (2 days) LabView Base 1 : 12 - 14.11.01 (3 jours) LabVIEW DAQ (F) : 15 & 16.11.01 (2 jours) Automates et réseaux de terrain : 13 & 14.11.01 (2 jours) Introduction to PERL 5 :  15 - 16.11.01  (2 days) LabVIEW - DAQ : 15 - 16.11.01 (2 jours) Introduction to XML :  19 - 20.11.01 (2 days) Introduction to C Programming :  21- 23.11.01 (3 days) Programmation TSX Premium 2 : 26 - 30.11.01 (5 jours) Object-Oriented Analysis and Design :  27 - 30.11.2001 (4 days) Hands...

  4. PLACES AVAILABLE

    CERN Multimedia

    Technical Training; Tel. 74924

    2001-01-01

    Places are available in the following courses: Nouveautés d'EXCEL : 5.11.01 (1/2 journée) Introduction a Windows 2000 au CERN : 6.11.01 (1/2 journée) UNIX pour non-programmeurs : 5 - 7.11.01 (3 jours) Design Patterns :  7 - 8.11.01 (2 days) The Java programming language Level 1: 8 - 9.11.01 (2 days) Automates et réseaux de terrain : 13 & 14.11.01 (3 jours) Introduction à Windows 2000 au CERN : 12 - 14.11.01 (1/2 journée) Introduction to Windows 2000 at CERN :  14.11.01  (half-day) Introduction to PERL 5 :  15 - 16.11.01  (2 days) Introduction to C Programming :  21- 23.11.01 (3 days) Programmation TSX Premium 2 : 26 - 30.11.01 (5 jours) Contract Follow-up (F) : 26.11.01 (1/2 journée) Object-Oriented Analysis and Design :  27 - 30.11.2001  (4 days) Hands-on Object-Oriented Design and Programming with C++ :  11 - 13.12.2...

  5. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: ELEC-2002 : Spring Term :  9, 11, 16, 18, 23, 25, 30.4.02 (7 * 2.5 hours) Object-Oriented Analysis & Design: 16 - 19.4.02  (4 days) The CERN Engineering Data Management System for Advanced users:  16.4.02  (1 day) Migration from AutoCAD 14 towards AutoCAD Mechanical6 PowerPack:  17 - 19.4 and 2 &3.5.02  (5 days) AutoCAD - niveau 1 : 22, 23, 29, 30.4 et 6, 7.5.02 (6 jours) LabVIEW base 1 : 22 - 24.4.02 (3 jours) CLEAN 2002 : working in a cleanroom:  24.4.02  (half-day, pm) LabVIEW DSC (F) 25 & 26.4.02 (2 jours) AutoCAD : Mise à jour AutoCAD r-14 vers 2002 : 25 & 26.4.02 (2 jours) Cotations selon les normes GPS de l'ISO : 29 - 30.4.02 (2 jours) Introduction to the CERN Engineering Data Management System:  7.5.02  (1 day) LabVIEW Basics 2 : 13 & 14.5.02 (2 days) AutoCAD Mechanical 6 PowerPack (F) : 13-...

  6. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: Introduction to the CERN Engineering Data Management System:  7.5.02  (1 day) LabVIEW Basics 2: 13 & 14.5.02 (2 days) AutoCAD Mechanical 6 PowerPack (F) : 13-14, 17, 21, 27-28.5.02 (6 jours) WorldFIP - Généralités : 14.5.2002 (1/2 journée) WorldFIP - Développer avec MicroFIP HANDLER : 14.5 - après-midi, 15.5.02 - matin (1 jour) WorldFIP - FullFIP FDM : FIP Device Manager (F) : 15.5 - après-midi, 16.5.02 - matin (1 jour) LabVIEW DAQ (F) : 15 & 16.5.02 (2 jours) EXCEL 2000 - niveau 2 : 22 & 23.5.02 (2 jours) The CERN Engineering Data Management System for Advanced users:  30.5.02  (1 day) LabVIEW Basics 1:  3 - 5.6.02  (3 days) AutoCAD 2002 - condensé : 4 - 6.6.02 (3 jours) LabVIEW DAQ (E):  6 & 7.6.02  (2 days) AutoCAD 2002 - Level 1:  10 - ...

  7. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: The CERN Engineering Data Management System for Advanced users : 16.4.02  (1 day) Migration from AutoCAD 14 towards AutoCAD Mechanical6 PowerPack:  17 - 19.4 and 2 &3.5.02  (5 days) AutoCAD - niveau 1 : 22, 23, 29, 30.4 et 6, 7.5.02 (6 jours) LabVIEW base 1 : 22 - 24.4.02 (3 jours) CLEAN 2002 : working in a cleanroom:  24.4.02  (half-day, pm) LabVIEW DSC (F) 25 & 26.4.02 (2 jours) AutoCAD : Mise à jour AutoCAD r-14 vers 2002 : 25 & 26.4.02 (2 jours) Cotations selon les normes GPS de l'ISO : 29 - 30.4.02 (2 jours) Introduction to the CERN Engineering Data Management System:  7.5.02  (1 day) LabVIEW Basics 2: 13 & 14.5.02 (2 days) AutoCAD Mechanical 6 PowerPack (F) : 13-14, 17, 21, 27-28.5.02 (6 jours) WorldFIP - Généralités : 14.5.2002 (1/2 journée) WorldFIP - Développer avec Micr...

  8. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: LabVIEW Basics 2: 13 & 14.5.02 (2 days) WorldFIP - Généralités : 14.5.2002 (1/2 journée) WorldFIP - Développer avec MicroFIP HANDLER : 14.5 - après-midi, 15.5.02 - matin (1 jour) WorldFIP - FullFIP FDM : FIP Device Manager (F) : 15.5 - après-midi, 16.5.02 - matin (1 jour) LabVIEW DAQ (F) : 15 & 16.5.02 (2 jours) EXCEL 2000 - niveau 2 : 22 & 23.5.02 (2 jours) The CERN Engineering Data Management System for Advanced users:  30.5.02  (1 day) LabVIEW Basics 1:  3 - 5.6.02  (3 days) AutoCAD 2002 - condensé : 4 - 6.6.02 (3 jours) LabVIEW DAQ (E):  6 & 7.6.02  (2 days) AutoCAD 2002 - Level 1:  10 - 12 and 24 - 26.6.02  (6 days) If you wish to participate in one of these courses, please discuss with your supervisor and apply electronically directly from the c...

  9. PLACES AVAILABLE

    CERN Multimedia

    Monique Duval

    2002-01-01

    Places are available in the following courses: LabVIEW base 1 : 22 - 24.4.02 (3 jours) CLEAN 2002 : working in a cleanroom:  24.4.02  (half-day, pm) LabVIEW DSC (F) 25 & 26.4.02 (2 jours) AutoCAD : Mise à jour AutoCAD r-14 vers 2002 : 25 & 26.4.02 (2 jours) Cotations selon les normes GPS de l'ISO : 29 - 30.4.02 (2 jours) Introduction to the CERN Engineering Data Management System:  7.5.02  (1 day) LabVIEW Basics 2: 13 & 14.5.02 (2 days) AutoCAD Mechanical 6 PowerPack (F) : 13-14, 17, 21, 27-28.5.02 (6 jours) WorldFIP - Généralités : 14.5.2002 (1/2 journée) WorldFIP - Développer avec MicroFIP HANDLER : 14.5 - après-midi, 15.5.02 - matin (1 jour) WorldFIP - FullFIP FDM : FIP Device Manager (F) : 15.5 - après-midi, 16.5.02 - matin (1 jour) LabVIEW DAQ (F) : 15 & 16.5.02 (2 jours) EXCEL 2000 - niveau 2 : 22 & 23.5.02 (2 jours)...

  10. Graphitization in Carbon MEMS and Carbon NEMS

    Science.gov (United States)

    Sharma, Swati

    Carbon MEMS (CMEMS) and Carbon NEMS (CNEMS) are an emerging class of miniaturized devices. Due to the numerous advantages such as scalable manufacturing processes, inexpensive and readily available precursor polymer materials, tunable surface properties and biocompatibility, carbon has become a preferred material for a wide variety of future sensing applications. Single suspended carbon nanowires (CNWs) integrated on CMEMS structures fabricated by electrospinning of SU8 photoresist on photolithographially patterned SU8 followed by pyrolysis are utilized for understanding the graphitization process in micro and nano carbon materials. These monolithic CNW-CMEMS structures enable the fabrication of very high aspect ratio CNWs of predefined length. The CNWs thus fabricated display core---shell structures having a graphitic shell with a glassy carbon core. The electrical conductivity of these CNWs is increased by about 100% compared to glassy carbon as a result of enhanced graphitization. We explore various tunable fabrication and pyrolysis parameters to improve graphitization in the resulting CNWs. We also suggest gas-sensing application of the thus fabricated single suspended CNW-CMEMS devices by using the CNW as a nano-hotplate for local chemical vapor deposition. In this thesis we also report on results from an optimization study of SU8 photoresist derived carbon electrodes. These electrodes were applied to the simultaneous detection of traces of Cd(II) and Pb(II) through anodic stripping voltammetry and detection limits as low as 0.7 and 0.8 microgL-1 were achieved. To further improve upon the electrochemical behavior of the carbon electrodes we elucidate a modified pyrolysis technique featuring an ultra-fast temperature ramp for obtaining bubbled porous carbon from lithographically patterned SU8. We conclude this dissertation by suggesting the possible future works on enhancing graphitization as well as on electrochemical applications

  11. Microbial degradation of monocyclic and polycyclic aromatic hydrocarbons in case of limited pollutant availability with nitrate as a potential electron acceptor; Der mikrobielle Abbau mono- und polyzyklischer aromatischer Kohlenwasserstoffe bei einer begrenzten Schadstoffverfuegbarkeit mit Nitrat als potentiellem Elektronenakzeptor

    Energy Technology Data Exchange (ETDEWEB)

    Linke, C.

    2001-07-01

    The possibility of using natural degradation processes for long-term remediation of tar oil contaminated sites was investigated. Field studies have shown that microbial decomposition of pollutants does take place in many sites but that it is limited by limited availability of pollutants and oxygen in soil. The investigations focused on the activation of BTEX and PAH degradation in situ by nitrate in the absence or in the presence of oxygen. Tensides should be used in order to enhance the availability of pollutants in water, especially in the case of hardly water-soluble PAH. A large-scale experiment was carried out on tar oil contaminated terrain; it was found that the availability of oxygen and not of PAH is the limiting factor so that adding of surfactants will not improve pollutant degradation. In contrast, the adding of tensides would mean even higher concentrations of oxygen-depleting substances in soil. [German] In der vorliegenden Arbeit wurden im Hinblick auf langfristige Sanierungsstrategien fuer teeroelkontaminierte Standorte Moeglichkeiten der Nutzung natuerlicher Abbauvorgaenge untersucht. Zahlreiche Feldstudien belegen, dass ein mikrobieller Schadstoffabbau an vielen Standorten stattfindet, dieser jedoch sowohl durch eine begrenzte Schadstoffverfuegbarkeit als auch durch den im Untergrund nur begrenzt zur Verfuegung stehenden Sauerstoff limitiert wird. Ziel dieser Arbeit war es abzuklaeren, inwiefern ein BTEX- und PAK-Abbau in situ auch in Abwesenheit von Sauerstoff durch Nitrat allein oder durch Nitrat in Kombination mit Sauerstoff aktiviert werden kann. Um insbesondere fuer die schlecht wasserloeslichen PAK eine ausreichende Schadstoffverfuegbarkeit zu gewaehrleisten, sollten auch Tenside zur Erhoehung der im Wasser vorliegenden Schadstoffmenge eingesetzt werden. Aufbauend auf die Laboruntersuchungen wurde im Rahmen von VEGAS{sup ix} ein Grossversuch zum mikrobiellen PAK-Abbau im Abstrom einer simulierten Teeroelkontamination durchgefuehrt

  12. [Not Available].

    Science.gov (United States)

    Chaibdraa, A; Medjellekh, M S; Saouli, A; Bentakouk, M C

    2008-12-31

    Le Pseudomonasest un agent pathogène à l'origine d'infections nosocomiales graves dans les centres des brûlés. Son opportunisme et sa virulence en font une préoccupation majeure. Ce travail se propose d'évaluer la place de cette bactérie dans l'écologie bactérienne locale et d'en apprécier la sensibilité aux antibiotiques. Cette étude rétrospective préliminaire porte sur la période de juin 2003 à décembre 2005. Elle intéresse l'ensemble des prélèvements bactériologiques ayant pu être réalisés au centre des brûlés d'Annaba. L'effectif est de 633 micro-organismes isolés dont 128 Pseudomonas (20,2%): 127 aeruginosa (99,2%), 1 fluorescens (0,8%); distribution selon le site de prélèvement: écouvillon (87,5%), prélèvement trachéobronchique (4,6%), hémoculture (3,1%), cathéters (1,6%), urine (1,6%) et sonde urinaire (1,6%). Le pyocyanique se situe après le staphylocoque pour les prélèvements précoces et repasse en tête après un séjour supérieur à une semaine, où 89% des pyocyaniques sont identifiés. Il est en première position dans les pneumopathies sous ventilation assistée invasive. Il se classe troisième dans les hémocultures et les cultures de cathéters. Dans les infections urinaires il est devancé par Candida et la flore périnéale. Les 128 antibiogrammes regroupent 314 réponses sensibles. La sensibilité à plus de deux antibiotiques est de 68%, à deux antibiotiques 24% et à un antibiotique 8%. Seules quatre molécules restent actives: ciprofloxacine > péfloxacine > pipéracilline > ceftazidime. Une résistance absolue est retrouvée pour trois Pseudomonas (2,4%). Le pronostic sévère des infections nosocomiales à pyocyanique et les risques d'options thérapeutiques très limitées font toute leur gravité, d'où l'intérêt de respecter des règles strictes de prescription des antibiotiques et des mesures de prévention.

  13. Quench limits

    International Nuclear Information System (INIS)

    Sapinski, M.

    2012-01-01

    With thirteen beam induced quenches and numerous Machine Development tests, the current knowledge of LHC magnets quench limits still contains a lot of unknowns. Various approaches to determine the quench limits are reviewed and results of the tests are presented. Attempt to reconstruct a coherent picture emerging from these results is taken. The available methods of computation of the quench levels are presented together with dedicated particle shower simulations which are necessary to understand the tests. The future experiments, needed to reach better understanding of quench limits as well as limits for the machine operation are investigated. The possible strategies to set BLM (Beam Loss Monitor) thresholds are discussed. (author)

  14. Spatiotemporal models of global soil organic carbon stock to support land degradation assessments at regional and global scales: limitations, challenges and opportunities

    Science.gov (United States)

    Hengl, Tomislav; Heuvelink, Gerard; Sanderman, Jonathan; MacMillan, Robert

    2017-04-01

    There is an increasing interest in fitting and applying spatiotemporal models that can be used to assess and monitor soil organic carbon stocks (SOCS), for example, in support of the '4 pourmille' initiative aiming at soil carbon sequestration towards climate change adaptation and mitigation and UN's Land Degradation Neutrality indicators and similar degradation assessment projects at regional and global scales. The land cover mapping community has already produced several spatiotemporal data sets with global coverage and at relatively fine resolution e.g. USGS MODIS land cover annual maps for period 2000-2014; European Space Agency land cover maps at 300 m resolution for the year 2000, 2005 and 2010; Chinese GlobeLand30 dataset available for years 2000 and 2010; Columbia University's WRI GlobalForestWatch with deforestation maps at 30 m resolution for the period 2000-2016 (Hansen et al. 2013). These data sets can be used for land degradation assessment and scenario testing at global and regional scales (Wei et al 2014). Currently, however, no compatible global spatiotemporal data sets exist on status of soil quality and/or soil health (Powlson et al. 2013). This paper describes an initial effort to devise and evaluate a procedure for mapping spatio-temporal changes in SOC stocks using a complete stack of soil forming factors (climate, relief, land cover, land use, lithology and living organisms) represented mainly through remote sensing based time series of Earth images. For model building we used some 75,000 geo-referenced soil profiles and a stacks space-time covariates (land cover, land use, biomass, climate) at two standard resolutions: (1) 10 km resolution with data available for period 1920-2014 and (2) 1000 m resolution with data available for period 2000-2014. The initial results show that, although it is technically feasible to produce space time estimates of SOCS that demonstrate the procedure, the estimates are relatively uncertain (<45% of variation

  15. Mitigating greenhouse: Limited time, limited options

    International Nuclear Information System (INIS)

    Moriarty, Patrick; Honnery, Damon

    2008-01-01

    Most human-caused climate change comes from fossil fuel combustion emissions. To avoid the risk of serious climate change, very recent research suggests that emission reductions will need to be both large and rapidly implemented. We argue that technical solutions-improving energy efficiency, use of renewable and nuclear energy, and carbon capture and sequestration-can only be of minor importance, mainly given the limited time available to take effective climate action. Only curbing energy use, perhaps through 'social efficiency' gains, particularly in the high-energy consumption countries, can provide the rapid emissions reductions needed. The social efficiency approach requires a basic rethinking in how we can satisfy our human needs with low environmental impacts. Large cuts in emissions could then occur rapidly, but only if resistance to such changes can be overcome. Particularly in transport, there are also serious potential conflicts between the technical and the social efficiency approaches, requiring a choice to be made

  16. Microbes in nature are limited by carbon and energy: the starving-survival lifestyle in soil and consequences for estimating microbial rates

    Directory of Open Access Journals (Sweden)

    John Eyres Hobbie

    2013-11-01

    Full Text Available Understanding microbial transformations in soils is important for predicting future carbon sequestration and nutrient cycling. This review questions some methods of assessing one key microbial process, the uptake of labile organic compounds. First, soil microbes have a starving-survival life style of dormancy, arrested activity, and low activity. Yet they are very abundant and remain poised to completely take up all substrates that become available. As a result, dilution assays with the addition of labeled substrates cannot be used. When labeled substrates are transformed into 14CO2, the first part of the biphasic release follows metabolic rules and is not affected by the environment. As a consequence, when identical amounts of isotopically substrates are added to soils from different climate zones, the same percentage of the substrate is respired and the same half-life of the respired 14CO2 from the labeled substrate is estimated. Second, when soils are sampled by a variety of methods from taking 10 cm diameter cores to millimeter-scale dialysis chambers, amino acids (and other organic compounds appear to be released by the severing of fine roots and mycorrhizal networks as well as from pressing or centrifuging treatments. As a result of disturbance as well as of natural root release, concentrations of individual amino acids of ~10 µM are measured. This contrasts with concentrations of a few nM found in aquatic systems and raises questions about possible differences in the bacterial strategy between aquatic and soil ecosystems. The small size of the hyphae (2-10 μm diameter and of the fine roots (0.2 to 2 mm diameter, make it very difficult to sample any volume of soil without introducing artifacts. Third, when micromolar amounts of labeled amino acids are added to soil, some of the isotope enters plant roots. This may be an artifact of the high µM concentrations applied.

  17. Microbes in nature are limited by carbon and energy: the starving-survival lifestyle in soil and consequences for estimating microbial rates.

    Science.gov (United States)

    Hobbie, John E; Hobbie, Erik A

    2013-01-01

    Understanding microbial transformations in soils is important for predicting future carbon sequestration and nutrient cycling. This review questions some methods of assessing one key microbial process, the uptake of labile organic compounds. First, soil microbes have a starving-survival life style of dormancy, arrested activity, and low activity. Yet they are very abundant and remain poised to completely take up all substrates that become available. As a result, dilution assays with the addition of labeled substrates cannot be used. When labeled substrates are transformed into (14)CO2, the first part of the biphasic release follows metabolic rules and is not affected by the environment. As a consequence, when identical amounts of isotopically substrates are added to soils from different climate zones, the same percentage of the substrate is respired and the same half-life of the respired (14)CO2 from the labeled substrate is estimated. Second, when soils are sampled by a variety of methods from taking 10 cm diameter cores to millimeter-scale dialysis chambers, amino acids (and other organic compounds) appear to be released by the severing of fine roots and mycorrhizal networks as well as from pressing or centrifuging treatments. As a result of disturbance as well as of natural root release, concentrations of individual amino acids of ~10 μM are measured. This contrasts with concentrations of a few nanomolar found in aquatic systems and raises questions about possible differences in the bacterial strategy between aquatic and soil ecosystems. The small size of the hyphae (2-10 μm diameter) and of the fine roots (0.2-2 mm diameter), make it very difficult to sample any volume of soil without introducing artifacts. Third, when micromolar amounts of labeled amino acids are added to soil, some of the isotope enters plant roots. This may be an artifact of the high micromolar concentrations applied.

  18. A numerical analysis of carbon dynamics of the Southern Ocean phytoplankton community: the roles of light and grazing in effecting both sequestration of atmospheric CO 2 and food availability to larval krill

    Science.gov (United States)

    Walsh, John J.; Dieterle, Dwight A.; Lenes, Jason

    2001-01-01

    Reduced ice extent within coastal regions of the Southern Ocean may lead to deeper surface mixed layers (SML), as prevail in offshore areas. A future decline of ice melt-induced stability of the water column may be associated with a shift in dominant food webs, from larger, sun-adapted diatoms grazed by euphausiids to smaller, shade-adapted flagellates consumed by salps. A basically one-dimensional numerical model of three dominant groups of the Antarctic phytoplankton community (diatoms, cryptophytes, and colonial prymnesiophytes) and four types of herbivore (protozoans, salps, copepods, and euphausiids) is used to explore the seasonal importance of both light limitation and grazing pressure on the amount of annual carbon sequestration and larval krill survival within contrasting oceanic and neritic waters, where respective validation data have been gathered during austral spring by the European JGOFS and RACER programs. With imposition of moderate and large grazing stresses, thought to be typical of offshore waters, we were able to replicate the European JGOFS 1992 observations of light penetration, phytoplankton biomass, primary production, pCO 2, bacterial biomass, labile DOC, ammonium, and total particle effluxes at 100 m within the deep SML of our model. The fidelity of such a large set of simulated state variables suggests that multiple limiting factors are indeed operating on different components of the oceanic phytoplankton community — selective grazing losses on the flagellates, but light limitation of diatoms. Release of protozoan grazing pressure in our model instead leads to unobserved spring blooms of cryptophytes, found only in laboratory enclosures. On an annual basis, weak sequestration of atmospheric CO 2 is simulated in a habitat typical of the Polar Front, while evasion of carbon dioxide occurs under biophysical conditions of the Antarctic Circumpolar Current. Stratification in shallow SML and the same absolute grazing demands by krill and

  19. Major limitations to achieving "4 per 1000" increases in soil organic carbon stock in temperate regions: Evidence from long-term experiments at Rothamsted Research, United Kingdom.

    Science.gov (United States)

    Poulton, Paul; Johnston, Johnny; Macdonald, Andy; White, Rodger; Powlson, David

    2018-01-21

    We evaluated the "4 per 1000" initiative for increasing soil organic carbon (SOC) by analysing rates of SOC increase in treatments in 16 long-term experiments in southeast United Kingdom. The initiative sets a goal for SOC stock to increase by 4‰ per year in the 0-40 cm soil depth, continued over 20 years. Our experiments, on three soil types, provided 114 treatment comparisons over 7-157 years. Treatments included organic additions (incorporated by inversion ploughing), N fertilizers, introducing pasture leys into continuous arable systems, and converting arable land to woodland. In 65% of cases, SOC increases occurred at >7‰ per year in the 0-23 cm depth, approximately equivalent to 4‰ per year in the 0-40 cm depth. In the two longest running experiments (>150 years), annual farmyard manure (FYM) applications at 35 t fresh material per hectare (equivalent to approx. 3.2 t organic C/ha/year) gave SOC increases of 18‰ and 43‰ per year in the 23 cm depth during the first 20 years. Increases exceeding 7‰ per year continued for 40-60 years. In other experiments, with FYM applied at lower rates or not every year, there were increases of 3‰-8‰ per year over several decades. Other treatments gave increases between zero and 19‰ per year over various periods. We conclude that there are severe limitations to achieving the "4 per 1000" goal in practical agriculture over large areas. The reasons include (1) farmers not having the necessary resources (e.g. insufficient manure); (2) some, though not all, practices favouring SOC already widely adopted; (3) practices uneconomic for farmers-potentially overcome by changes in regulations or subsidies; (4) practices undesirable for global food security. We suggest it is more realistic to promote practices for increasing SOC based on improving soil quality and functioning as small increases can have disproportionately large beneficial impacts, though not necessarily translating into increased crop yield

  20. Carbonate aquifers

    Science.gov (United States)

    Cunningham, Kevin J.; Sukop, Michael; Curran, H. Allen

    2012-01-01

    Only limited hydrogeological research has been conducted using ichnology in carbonate aquifer characterization. Regardless, important applications of ichnology to carbonate aquifer characterization include its use to distinguish and delineate depositional cycles, correlate mappable biogenically altered surfaces, identify zones of preferential groundwater flow and paleogroundwater flow, and better understand the origin of ichnofabric-related karst features. Three case studies, which include Pleistocene carbonate rocks of the Biscayne aquifer in southern Florida and Cretaceous carbonate strata of the Edwards–Trinity aquifer system in central Texas, demonstrate that (1) there can be a strong relation between ichnofabrics and groundwater flow in carbonate aquifers and (2) ichnology can offer a useful methodology for carbonate aquifer characterization. In these examples, zones of extremely permeable, ichnofabric-related macroporosity are mappable stratiform geobodies and as such can be represented in groundwater flow and transport simulations.

  1. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Education Centers Carbon Monoxide Information Center Carbon Monoxide Information Center En Español The Invisible Killer Carbon monoxide, ... Install one and check its batteries regularly. View Information About CO Alarms Other CO Topics Safety Tips ...

  2. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Education Safety Education Centers Carbon Monoxide Information Center Carbon Monoxide Information Center En Español The Invisible Killer Carbon monoxide, also known as CO, is called the " ...

  3. Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current

    Digital Repository Service at National Institute of Oceanography (India)

    Assmy, P.; Smetacek, V.; Montresor, M.; Klaas, C.; Henjes, J.; Strass, V.H.; Arrieta, J.M.; Bathmann, U.; Berg, G.M.; Breitbarth, E.; Cisewski, B.; Friedrichs, L.; Fuchs, N.; Herndl, G.J.; Jansen, S.; Kragefsky, S.; Latasa, M.; Peeken, I.; Rottgers, R.; Scharek, R.; Schuller, S.E.; Steigenberger, S.; Webb, A.; Wolf-Gladrow, D.

    Trans A Math Phys Eng Sci 366(1882):3947–3967. 35. Smetacek V, et al. (2012) Deep carbon export from a Southern Ocean iron-fertilized diatom bloom. Nature 487(7407):313–319. 36. Assmy P, Henjes J, Klaas C, Smetacek V (2007) Mechanisms determining species...

  4. How and to what extent does precipitation on multi-temporal scales and soil moisture at different depths determine carbon flux responses in a water-limited grassland ecosystem?

    Science.gov (United States)

    Fang, Qingqing; Wang, Guoqiang; Xue, Baolin; Liu, Tingxi; Kiem, Anthony

    2018-04-23

    In water-limited ecosystems, hydrological processes significantly affect the carbon flux. The semi-arid grassland ecosystem is particularly sensitive to variations in precipitation (PRE) and soil moisture content (SMC), but to what extent is not fully understood. In this study, we estimated and analyzed how hydrological variables, especially PRE at multi-temporal scales (diurnal, monthly, phenological-related, and seasonal) and SMC at different soil depths (0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm) affect the carbon flux. For these aims, eddy covariance data were combined with a Vegetation Photosynthesis and Respiration Model (VPRM) to simulate the regional gross primary productivity (GPP), ecosystem respiration (R eco ), and net ecosystem exchange of CO 2 (NEE). Interestingly, carbon flux showed no relationship with diurnal PRE or phenological-related PRE (precipitation in the growing season and non-growing season). However, carbon flux was significantly related to monthly PRE and to seasonal PRE (spring + summer, autumn). The GPP, R eco , and NEE increased in spring and summer but decreased in autumn with increasing precipitation due to the combined effect of salinization in autumn. The GPP, R eco , and NEE were more responsive to SMC at 0-20 cm depth than at deeper depths due to the shorter roots of herbaceous vegetation. The NEE increased with increasing monthly PRE because soil microbes responded more quickly than plants. The NEE significantly decreased with increasing SMC in shallow surface due to a hysteresis effect on water transport. The results of our study highlight the complex processes that determine how and to what extent PRE at multi-temporal scale and SMC at different depths affect the carbon flux response in a water-limited grassland. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Flexible Carbon Aerogels

    Directory of Open Access Journals (Sweden)

    Marina Schwan

    2016-09-01

    Full Text Available Carbon aerogels are highly porous materials with a large inner surface area. Due to their high electrical conductivity they are excellent electrode materials in supercapacitors. Their brittleness, however, imposes certain limitations in terms of applicability. In that context, novel carbon aerogels with varying degree of flexibility have been developed. These highly porous, light aerogels are characterized by a high surface area and possess pore structures in the micrometer range, allowing for a reversible deformation of the aerogel network. A high ratio of pore size to particle size was found to be crucial for high flexibility. For dynamic microstructural analysis, compression tests were performed in-situ within a scanning electron microscope allowing us to directly visualize the microstructural flexibility of an aerogel. The flexible carbon aerogels were found to withstand between 15% and 30% of uniaxial compression in a reversible fashion. These findings might stimulate further research and new application fields directed towards flexible supercapacitors and batteries.

  6. The relationship between carbon dioxide concentration and visitor numbers in the homothermic zone of the Balcarka Cave (Moravian Karst during a period of limited ventilation

    Directory of Open Access Journals (Sweden)

    Marek Lang

    2015-05-01

    Full Text Available The evolution of CO2 levels with and without human presence was studied in a selected site (Gallery Chamber of the homothermic zone of the Balcarka Cave (Moravian Karst, Czech Republic during the fall, a period of limited ventilation. There were recognized various factors controlling the cave CO2 levels under different conditions in the exterior and interior. When visitors were absent, CO2 levels were controlled by the advective CO2 fluxes linked to cave airflows and reaching up to ~1.5x10-3 mol s-1. These fluxes exceed by orders of magnitude the exchanged diffusive fluxes (up to 4.8x10-8 mol s-1 and also the natural net flux (from 1.7x10-6 to 6.7x10-6 mol s-1imputing given chamber directly from overburden. The natural net flux, normalized to unitary surface area, was estimated to be 2.8x10-8 to 1.1x10-7 mol m-2 s-1, based on a perpendicular projection area of the chamber of ~ 60 m2. When visitors were present, the anthropogenic CO2 flux into the chamber reached up to 3.5x10-3 mol s-1, which slightly exceeded the advective fluxes. This flux, recalculated per one person, yields the value of 6.7x10-5 mol s-1. The calculations of reachable steady states indicate that anthropogenic fluxes could almost triple the natural CO2 levels if visitors stayed sufficiently long in the cave.

  7. Carbon sequestration in agricultural soils: a potential carbon trading opportunity?

    International Nuclear Information System (INIS)

    Cowie, Annette L.; Murphy, Brian; Rawson, Andrew; Wilson, Brian; Singh, Bhupinderpal; Young, Rick; Grange, Ian

    2007-01-01

    Full text: Emissions trading schemes emerging in Australia and internationally create a market mechanism by which release of greenhouse gases incurs a cost, and implementation of abatement measures generates a financial return. There is growing interest amongst Australian landholders in emissions trading based on sequestration of carbon in soil through modified land management practices. Intensively cropped soils have low carbon content, due to disturbance, erosion and regular periods of minimal organic matter input. Because cropping soils in Australia have lost a substantial amount of carbon there is significant potential to increase carbon stocks through improved land management practices. Evidence from long term trials and modelling indicates that modified cropping practices (direct drilling, stubble retention, controlled traffic) have limited impact on soil carbon (0 to +2 tC02e ha-' year1) whereas conversion from cropping to pasture gives greater increases. Small-increases in soil carbon over large areas can contribute significantly to mitigation of Australia's greenhouse gas emissions. Furthermore, increase in soil organic matter will improve soil health, fertility and resilience. However, the inclusion of soil carbon offsets in an emissions trading scheme cannot occur until several barriers are overcome. The first relates to credibility. Quantification of the extent to which specific land management practices can sequester carbon in different environments will provide the basis for promotion of the concept. Current research across Australia is addressing this need. Secondly, cost-effective and accepted methods of estimating soil carbon change must be available. Monitoring soil carbon to document change on a project scale is not viable due to the enormous variability in carbon stocks on micro and macro scales. Instead estimation of soil carbon change could be undertaken through a combination of baseline measurement to assess the vulnerability of soil carbon

  8. Expression of the pyr operon of Lactobacillus plantarum is regulated by inorganic carbon availability through a second regulator, PyrR2, homologous to the pyrimidine-dependent regulator PyrR1

    DEFF Research Database (Denmark)

    Arsène-Ploetze, Florence; Valérie Kugler, Valérie; Martinussen, Jan

    2006-01-01

    Inorganic carbon (IC), such as bicarbonate or carbon dioxide, stimulates the growth of Lactobacillus plantarum. At low IC levels, one-third of natural isolated L. plantarum strains are nutritionally dependent on exogenous arginine and pyrimidine, a phenotype previously defined as high-CO2-requiri...

  9. Disponibilidade de nitrogênio pela oxidação do carbono lábil com permanganato de potássio Availability of nitrogen by the oxidation of the labile carbon with potassium permanganate

    Directory of Open Access Journals (Sweden)

    Celsemy E. Maia

    2003-12-01

    Full Text Available O presente trabalho teve como objetivo avaliar a liberação do nitrogênio associado ao carbono lábil oxidado com KMnO4 333 mmol L-1 e verificar a capacidade supridora de nitrogênio pela sua correlação com o nitrogênio absorvido pelas plantas. O solo utilizado foi proveniente de um experimento com milho em um Argissolo Vermelho-Amarelo, cultivado com milho desde 1984, cuja produtividade vem sendo avaliada em função das doses de 0 e 40 m³ ha-1 ano-1 de composto orgânico (palha de soja e feijão com esterco bovino combinadas com 0, 250 e 500 kg ha-1 ano-1 da fórmula 4-14-8 aplicados no plantio, e 0, 100 e 200 kg ha-1 ano-1 de sulfato de amônio em cobertura. Os resultados mostraram que o uso da matéria orgânica contribuiu para uma quantidade maior de nitrogênio solúvel em KMnO4 333 mmol L-1; o teor de nitrogênio solúvel em KMnO4 333 mmol L-1 foi superior ao obtido pelo método anaeróbico e se correlacionou significativamente com o carbono total, carbono lábil, nitrogênio total, teor de amônio e nitrato e com o nitrogênio biodisponível.The present work had the objective of evaluating the liberation of the nitrogen associated to the labile carbon oxidized with KMnO4 (333 mmol L-1 and to verify the supply capacity of nitrogen by its correlation with the nitrogen absorbed by the plants. The soil used belongs to a Cambic Yellow Red Podzol, cultivated with corn since 1984, and its productivity is being evaluated as a function of the doses of 0 and 40 m³ ha-1 year-1 of organic compost (beans and soybean straw with manure, combined with 0, 250 and 500 kg ha-1 year-1 of the formula 4-14-8 applied at planting and 0, 100 and 200 kg ha-1 year-1 of ammonium sulphate as top dressing. The results showed that the use of the organic material contributed to a higher amount of nitrogen soluble in KMnO4 (333 mmol L-1. The content of soluble nitrogen in KMnO4 (333 mmol L-1 was found to be superior than that obtained by the anaerobic method and

  10. [Currently available skin substitutes].

    Science.gov (United States)

    Oravcová, Darina; Koller, Ján

    2014-01-01

    The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. Autologous split or full-thickness skin graft are the best definitive burn wound coverage, but it is constrained by the limited available sources, especially in major burns. Donor site morbidities in term of additional wounds and scarring are also of concern of the autograft application. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. This paper reviews currently available skin substitutes, produced in not for-profit skin banks as well as commercially available. They are divided according to type of material included, as biological, biosynthetic and synthetic and named respectively.

  11. The influence of land-use and land-management on Soil Organic Carbon concentrations: Limitations of making predictions using only soil order data

    Science.gov (United States)

    Bell, M. J.; Worrall, F.

    2009-04-01

    In light of recent concern over the extent of global warming and the role of soil carbon as a potential store of atmospheric carbon, there is increasing demand for regions to estimate their current soil organic carbon (SOC) stocks with the greatest possible accuracy. Several previous attempts at calculating SOC baselines at global, national or regional scale have used mean values for soil orders and multiplied these values by the mapped areas of the soils they represent. Other methods have approached the task from a land cover point of view, making estimates using only land-use, or soil order/land-use combinations and others have included variables such as altitude, climate and soil texture. This study aimed to assess the major controls on SOC concentrations (%SOC) at the National Trust Wallington estate in Northumberland, NE England (area = 55km2) where an extensive soil sampling campaign was used to test what level of accuracy could be achieved in modelling the %SOC values on the Estate. Mapped %SOC values were compared to the values predicted from The National Soils Resources Institute (NSRI) representative soil profile data for major soil group, soil series and land-use corrected soil series values, as well as land-use/major soil group combinations from the Countryside Survey database. The results of this study can be summarised as follows: When only soil series or land-use were used as predictors only 48% and 44% of the variation in the dataset were explained. When soil series/land-use combinations were used explanatory power increased to 57% both altitude and soil pH are major controls on %SOC and including these variables gave an improvement to 59% A further improvement from 59% to 66% in the ability to predict %SOC levels at point locations when farm tenancy was included indicates that differences in land-management practices between farm tenancies explained more of the variation than either soil series or land-use in %SOC. Further work will involve a

  12. Estimations of actual availability

    International Nuclear Information System (INIS)

    Molan, M.; Molan, G.

    2001-01-01

    Adaptation of working environment (social, organizational, physical and physical) should assure higher level of workers' availability and consequently higher level of workers' performance. A special theoretical model for description of connections between environmental factors, human availability and performance was developed and validated. The central part of the model is evaluations of human actual availability in the real working situation or fitness for duties self-estimation. The model was tested in different working environments. On the numerous (2000) workers, standardized values and critical limits for an availability questionnaire were defined. Standardized method was used in identification of the most important impact of environmental factors. Identified problems were eliminated by investments in the organization in modification of selection and training procedures in humanization of working .environment. For workers with behavioural and health problems individual consultancy was offered. The described method is a tool for identification of impacts. In combination with behavioural analyses and mathematical analyses of connections, it offers possibilities to keep adequate level of human availability and fitness for duty in each real working situation. The model should be a tool for achieving adequate level of nuclear safety by keeping the adequate level of workers' availability and fitness for duty. For each individual worker possibility for estimation of level of actual fitness for duty is possible. Effects of prolonged work and additional tasks should be evaluated. Evaluations of health status effects and ageing are possible on the individual level. (author)

  13. Selective Advantage of a Spirillum sp. in a Carbon-limited Environment. Accumulation of Poly-β-hydroxybutyric Acid and Its Role in Starvation

    NARCIS (Netherlands)

    Matin, A.; Veldhuis, C.; Stegeman, V.; Veenhuis, M.

    1979-01-01

    A freshwater Spirillum sp., which apparently belongs to a niche of low nutritional status, accumulated poly-β-hydroxybutyric acid (PHB) during lactate-limited growth in continuous culture. The PHB content varied in a complex manner with the dilution rate (D), but was greatest at the lowest D value

  14. Carbon sequestration by afforestation and revegetation as a means of limiting net-CO2 emissions in Iceland. COST E21 Workshop. Contribution of forests and forestry to mitigate greenhouse effects. Joensuu (Finland. 28-30 Sep 2000

    Directory of Open Access Journals (Sweden)

    Sigurdsson B.D.

    2000-01-01

    Full Text Available Iceland has lost about 95/ of its woodlands and 50/ of its vegetative cover during the 1,100 years of human settlement. Efforts to reclaim lost woodlands and herbaceous ecosystems have been continuing since the early 20th century. It is emphasised that for Icelandic conditions, effective carbon sequestration can be achieved by restoring (reclaiming herbaceous ecosystems on carbon-poor soils. Since 1990, about 4,000 ha per year have been afforested or revegetated. In 1995, the estimated C-sequestration of those areas was 65,100 t CO2, or 2.9/ of the national emissions for that year. In 1999, the estimated sequestration was up in 127,600 t CO2, or 4.7/ of the predicted CO2 emissions for the year 2000.

  15. Optimal decisions of countries with carbon tax and carbon tariff

    Directory of Open Access Journals (Sweden)

    Yumei Hou

    2015-05-01

    Full Text Available Purpose: Reducing carbon emission has been the core problem of controlling global warming and climate deterioration recently. This paper focuses on the optimal carbon taxation policy levied by countries and the impact on firms’ optimal production decisions. Design/methodology/approach: This paper uses a two-stage game theory model to analyze the impact of carbon tariff and tax. Numerical simulation is used to supplement the theoretical analysis. Findings: Results derived from the paper indicate that the demand in an unstable market is significantly affected by environmental damage level. Carbon tariff is a policy-oriented tax while the carbon tax is a market-oriented one. Comprehensive carbon taxation policy benefit developed countries and basic policy is more suitable for developing countries. Research limitations/implications: In this research, we do not consider random demand and asymmetric information, which may not well suited the reality. Originality/value: This work provides a different perspective in analyzing the impact of carbon tax and tariff. It is the first study to consider two consuming market and the strategic game between two countries. Different international status of countries considered in the paper is also a unique point.

  16. Phosphorus limitation and heat stress decrease calcification in Emiliania huxleyi

    Directory of Open Access Journals (Sweden)

    A. C. Gerecht

    2018-02-01

    Full Text Available Calcifying haptophytes (coccolithophores sequester carbon in the form of organic and inorganic cellular components (coccoliths. We examined the effect of phosphorus (P limitation and heat stress on particulate organic and inorganic carbon (calcite production in the coccolithophore Emiliania huxleyi. Both environmental stressors are related to rising CO2 levels and affect carbon production in marine microalgae, which in turn impacts biogeochemical cycling. Using semi-continuous cultures, we show that P limitation and heat stress decrease the calcification rate in E. huxleyi. However, using batch cultures, we show that different culturing approaches (batch versus semi-continuous induce different physiologies. This affects the ratio of particulate inorganic (PIC to organic carbon (POC and complicates general predictions on the effect of P limitation on the PIC  ∕  POC ratio. We found heat stress to increase P requirements in E. huxleyi, possibly leading to lower standing stocks in a warmer ocean, especially if this is linked to lower nutrient input. In summary, the predicted rise in global temperature and resulting decrease in nutrient availability may decrease CO2 sequestration by E. huxleyi through lower overall carbon production. Additionally, the export of carbon may be diminished by a decrease in calcification and a weaker coccolith ballasting effect.

  17. Production of precipitated calcium carbonate from calcium silicates and carbon dioxide

    International Nuclear Information System (INIS)

    Teir, Sebastian; Eloneva, Sanni; Zevenhoven, Ron

    2005-01-01

    The possibilities for reducing carbon dioxide emissions from the pulp and paper industry by calcium carbonation are presented. The current precipitated calcium carbonate (PCC) production uses mined, crushed calcium carbonate as raw materials. If calcium silicates were used instead, carbon dioxide emissions from the calcination of carbonates would be eliminated. In Finland, there could, thus, be a potential for eliminating 200 kt of carbon dioxide emissions per year, considering only the PCC used in the pulp and paper industry. A preliminary investigation of the feasibility to produce PCC from calcium silicates and the potential to replace calcium carbonate as the raw material was made. Calcium carbonate can be manufactured from calcium silicates by various methods, but only a few have been experimentally verified. The possibility and feasibility of these methods as a replacement for the current PCC production process was studied by thermodynamic equilibrium calculations using HSC software and process modelling using Aspen Plus[reg]. The results from the process modelling showed that a process that uses acetic acid for extraction of the calcium ions is a high potential option for sequestering carbon dioxide by mineral carbonation. The main obstacle seems to be the limited availability and relatively high price of wollastonite, which is a mineral with high calcium silicate content. An alternative is to use the more common, but also more complex, basalt rock instead

  18. Influences of rising atmospheric carbon dioxide and ozone concentrations on soil respiration, soil microbial biomass, nutrient availability and soil C dynamics in a soybean-wheat no-till system

    Science.gov (United States)

    Effects of the elevated carbon dioxide and ozone on agroecosystems include effects on root growth, soil microbiology and soil C dynamics although the combined effects of these gases on belowground processes have been little studied. The objective of this experiment was to determine the separate and...

  19. Re-assessment of plant carbon dynamics at the Duke free-air CO2 enrichment site: interactions of atmospheric [CO2] with nitrogen and water availability over stand development

    Science.gov (United States)

    Heather R. McCarthy; Ram Oren; Kurt H Johnsen; Anne Gallet-Budynek; Seth G. Pritchard; Charles W Cook; Shannon L. LaDeau; Robert B. Jackson; Adrien C. Finzi

    2010-01-01

    The potential for elevated [CO2]-induced changes to plant carbon (C) storage, through modifications in plant production and allocation of C among plant pools, is an important source of uncertainty when predicting future forest function. Utilizing 10 yr of data from the Duke free-air CO2 enrichment site, we evaluated the...

  20. Thermostable Carbonic Anhydrases in Biotechnological Applications

    Directory of Open Access Journals (Sweden)

    Anna Di Fiore

    2015-07-01

    Full Text Available Carbonic anhydrases are ubiquitous metallo-enzymes which catalyze the reversible hydration of carbon dioxide in bicarbonate ions and protons. Recent years have seen an increasing interest in the utilization of these enzymes in CO2 capture and storage processes. However, since this use is greatly limited by the harsh conditions required in these processes, the employment of thermostable enzymes, both those isolated by thermophilic organisms and those obtained by protein engineering techniques, represents an interesting possibility. In this review we will provide an extensive description of the thermostable carbonic anhydrases so far reported and the main processes in which these enzymes have found an application.

  1. Successional dynamics drive tropical forest nutrient limitation

    Science.gov (United States)

    Chou, C.; Hedin, L. O. O.

    2017-12-01

    It is increasingly recognized that nutrients such as N and P may significantly constrain the land carbon sink. However, we currently lack a complete understanding of these nutrient cycles in forest ecosystems and how to incorporate them into Earth System Models. We have developed a framework of dynamic forest nutrient limitation, focusing on the role of secondary forest succession and canopy gap disturbances as bottlenecks of high plant nutrient demand and limitation. We used succession biomass data to parameterize a simple ecosystem model and examined the dynamics of nutrient limitation throughout tropical secondary forest succession. Due to the patterns of biomass recovery in secondary tropical forests, we found high nutrient demand from rapid biomass accumulation in the earliest years of succession. Depending on previous land use scenarios, soil nutrient availability may also be low in this time period. Coupled together, this is evidence that there may be high biomass nutrient limitation early in succession, which is partially met by abundant symbiotic nitrogen fixation from certain tree species. We predict a switch from nitrogen limitation in early succession to one of three conditions: (i) phosphorus only, (ii) phosphorus plus nitrogen, or (iii) phosphorus, nitrogen, plus light co-limitation. We will discuss the mechanisms that govern the exact trajectory of limitation as forests build biomass. In addition, we used our model to explore scenarios of tropical secondary forest impermanence and the impacts of these dynamics on ecosystem nutrient limitation. We found that secondary forest impermanence exacerbates nutrient limitation and the need for nitrogen fixation early in succession. Together, these results indicate that biomass recovery dynamics early in succession as well as their connection to nutrient demand and limitation are fundamental for understanding and modeling nutrient limitation of the tropical forest carbon sink.

  2. Sulfur availability regulates plant growth via glucose-TOR signaling.

    Science.gov (United States)

    Dong, Yihan; Silbermann, Marleen; Speiser, Anna; Forieri, Ilaria; Linster, Eric; Poschet, Gernot; Allboje Samami, Arman; Wanatabe, Mutsumi; Sticht, Carsten; Teleman, Aurelio A; Deragon, Jean-Marc; Saito, Kazuki; Hell, Rüdiger; Wirtz, Markus

    2017-10-27

    Growth of eukaryotic cells is regulated by the target of rapamycin (TOR). The strongest activator of TOR in metazoa is amino acid availability. The established transducers of amino acid sensing to TOR in metazoa are absent in plants. Hence, a fundamental question is how amino acid sensing is achieved in photo-autotrophic organisms. Here we demonstrate that the plant Arabidopsis does not sense the sulfur-containing amino acid cysteine itself, but its biosynthetic precursors. We identify the kinase GCN2 as a sensor of the carbon/nitrogen precursor availability, whereas limitation of the sulfur precursor is transduced to TOR by downregulation of glucose metabolism. The downregulated TOR activity caused decreased translation, lowered meristematic activity, and elevated autophagy. Our results uncover a plant-specific adaptation of TOR function. In concert with GCN2, TOR allows photo-autotrophic eukaryotes to coordinate the fluxes of carbon, nitrogen, and sulfur for efficient cysteine biosynthesis under varying external nutrient supply.

  3. Modeling and estimating system availability

    International Nuclear Information System (INIS)

    Gaver, D.P.; Chu, B.B.

    1976-11-01

    Mathematical models to infer the availability of various types of more or less complicated systems are described. The analyses presented are probabilistic in nature and consist of three parts: a presentation of various analytic models for availability; a means of deriving approximate probability limits on system availability; and a means of statistical inference of system availability from sparse data, using a jackknife procedure. Various low-order redundant systems are used as examples, but extension to more complex systems is not difficult

  4. Carbon Based Nanotechnology: Review

    Science.gov (United States)

    Srivastava, Deepak; Saini, Subhash (Technical Monitor)

    1999-01-01

    This presentation reviews publicly available information related to carbon based nanotechnology. Topics covered include nanomechanics, carbon based electronics, nanodevice/materials applications, nanotube motors, nano-lithography and H2O storage in nanotubes.

  5. Methods for Instructional Diagnosis with Limited Available Resources.

    Science.gov (United States)

    Gillmore, Gerald M.; Clark, D. Joseph

    College teaching should be approached with the same careful delineation of problems and systematic attempts to find solutions which characterize research. Specific methods for the diagnosis of instructional problems include audio-video taping, use of teaching assistants, colleague assistance, classroom tests, student projects in and out of class,…

  6. Does High Educational Attainment Limit the Availability of Romantic Partners?

    Science.gov (United States)

    Burt, Isaac; Lewis, Sally V.; Beverly, Monifa G.; Patel, Samir H.

    2010-01-01

    Research indicates that highly educated individuals endure hardships in finding suitable romantic partners. Romantic hardships affect social and emotional adjustment levels, leading to low self-efficacy in relationship decision making. To address the need for research pertaining to this topic, the authors explored the experiences of eight…

  7. The limits of the available land and other natural resources

    International Nuclear Information System (INIS)

    Sonnino, Andrea; )

    2015-01-01

    The world's agricultural production system can satisfy the global demand for food, but consumes natural resources on which it is based earth, soil, water and Biodiversity at a higher rate on their ability natural regeneration and it is therefore not sustainable in the long term. The planned expansion quali-quantitatively goes global demand for food will further exacerbate the scarcity of arable land and other natural resources on which agricultural production. The challenge we face is therefore to meet growing world food demand reducing the environmental impacts of three major systems me to be productive today: the destruction of eco- Natural-systems derived from the expansion of the border agricultural; climate change caused by meadows that agricultural and livestock and deforestation; and the reduction of reserves of fresh water, because both Extraction rates higher than those of reintegration, that pollution of aquifers [it

  8. CARBON NEUTRON STAR ATMOSPHERES

    International Nuclear Information System (INIS)

    Suleimanov, V. F.; Klochkov, D.; Werner, K.; Pavlov, G. G.

    2014-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in the chemical composition of their atmospheres. For example, the atmospheres of thermally emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in Cas A, a pure carbon atmosphere has recently been suggested by Ho and Heinke. To test this composition for other similar sources, a publicly available detailed grid of the carbon model atmosphere spectra is needed. We have computed this grid using the standard local thermodynamic equilibrium approximation and assuming that the magnetic field does not exceed 10 8  G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra

  9. Hydroxylamine-induced oxidation of ferrous carbonylated truncated hemoglobins from Mycobacterium tuberculosis and Campylobacter jejuni is limited by carbon monoxide dissociation.

    Science.gov (United States)

    Ascenzi, Paolo; Ciaccio, Chiara; Gasperi, Tecla; Pesce, Alessandra; Caporaso, Lucia; Coletta, Massimo

    2017-08-01

    Hydroxylamine (HA) is an oxidant of ferrous globins and its action has been reported to be inhibited by CO, even though this mechanism has not been clarified. Here, kinetics of the HA-mediated oxidation of ferrous carbonylated Mycobacterium tuberculosis truncated hemoglobin N and O (Mt-trHbN(II)-CO and Mt-trHbO(II)-CO, respectively) and Campylobacter jejuni truncated hemoglobin P (Cj-trHbP(II)-CO), at pH 7.2 and 20.0 °C, are reported. Mixing Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO solution with the HA solution brings about absorption spectral changes reflecting the disappearance of the ferrous carbonylated derivatives with the concomitant formation of the ferric species. HA oxidizes irreversibly Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO with the 1:2 stoichiometry. The dissociation of CO turns out to be the rate-limiting step for the oxidation of Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO by HA. Values of the second-order rate constant for HA-mediated oxidation of Mt-trHbN(II)-CO, Mt-trHbO(II)-CO, and Cj-trHbP(II)-CO range between 8.8 × 10 4 and 8.6 × 10 7 M -1 s -1 , reflecting different structural features of the heme distal pocket. This study (1) demonstrates that the inhibitory effect of CO is linked to the dissociation of this ligand, giving a functional basis to previous studies, (2) represents the first comparative investigation of the oxidation of ferrous carbonylated bacterial 2/2 globins belonging to the N, O, and P groups by HA, (3) casts light on the correlation between kinetics of HA-mediated oxidation and carbonylation of globins, and (4) focuses on structural determinants modulating the HA-induced oxidation process.

  10. Carbon dynamics in trees: feast or famine?

    Science.gov (United States)

    Anna Sala; David R. Woodruff; Fredrick C. Meinzer

    2012-01-01

    Research on the degree to which carbon (C) availability limits growth in trees, as well as recent trends in climate change and concurrent increases in drought related tree mortality, have led to a renewed focus on the physiological mechanisms associated with tree growth responses to current and future climate. This has led to some dispute over the role of stored...

  11. Phosphorus limitation and heat stress decrease calcification in Emiliania huxleyi

    Science.gov (United States)

    Gerecht, Andrea C.; Šupraha, Luka; Langer, Gerald; Henderiks, Jorijntje

    2018-02-01

    Calcifying haptophytes (coccolithophores) sequester carbon in the form of organic and inorganic cellular components (coccoliths). We examined the effect of phosphorus (P) limitation and heat stress on particulate organic and inorganic carbon (calcite) production in the coccolithophore Emiliania huxleyi. Both environmental stressors are related to rising CO2 levels and affect carbon production in marine microalgae, which in turn impacts biogeochemical cycling. Using semi-continuous cultures, we show that P limitation and heat stress decrease the calcification rate in E. huxleyi. However, using batch cultures, we show that different culturing approaches (batch versus semi-continuous) induce different physiologies. This affects the ratio of particulate inorganic (PIC) to organic carbon (POC) and complicates general predictions on the effect of P limitation on the PIC  /  POC ratio. We found heat stress to increase P requirements in E. huxleyi, possibly leading to lower standing stocks in a warmer ocean, especially if this is linked to lower nutrient input. In summary, the predicted rise in global temperature and resulting decrease in nutrient availability may decrease CO2 sequestration by E. huxleyi through lower overall carbon production. Additionally, the export of carbon may be diminished by a decrease in calcification and a weaker coccolith ballasting effect.

  12. Carbon allocation in forest ecosystems

    Science.gov (United States)

    Creighton M. Litton; James W. Raich; Michael G. Ryan

    2007-01-01

    Carbon allocation plays a critical role in forest ecosystem carbon cycling. We reviewed existing literature and compiled annual carbon budgets for forest ecosystems to test a series of hypotheses addressing the patterns, plasticity, and limits of three components of allocation: biomass, the amount of material present; flux, the flow of carbon to a component per unit...

  13. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  14. Availability of enrichment services

    International Nuclear Information System (INIS)

    Svenke, E.

    1977-01-01

    The report summarizes major uncertainties which are likely to influence future demands for uranium isotopic enrichment. Since for the next decade the development of nuclear power will be largely concerned with the increment in demand the timely need for enrichment capacity will be particularly sensitive to assumptions about growth rates. Existing worldwide capacity together with capacities under construction will be sufficient well into the 1980's. However, long decision and construction leadtime, uncertainty as to future demand as well as other factors, specifically high capital need, all of which entail financial risks, create hindrances to a timely development of increment. The adequacy of current technology is well demonstrated in plant operation and new technology is under way. Technology is, however, not freely available on a purely commercial basis. Commercial willingness, which anticipates a limited degree of financial risk, is requesting both long term back-up from the utilities that would parallel their firm decisions on the acquisition of nuclear power units, and a protective government umbrella. This situation depends on the symbiotic relationship that exists between the nuclear power generating organizations, the enrichment undertakings and the governments involved. The report accordingly stresses the need for a more cooperative approach and this, moreover, at the multinational level. There is otherwise a risk that proper resources and financing means will not be allocated to the enrichment sector. Export limitations that request the highest degree of industrial processing of nuclear fuel, i.e. the compulsory enrichment of natural uranium, do not serve the interests of overall industrial efficiency

  15. Effect of soil carbohydrates on nutrient availability in natural forests and cultivated lands in Sri Lanka

    Science.gov (United States)

    Ratnayake, R. R.; Seneviratne, G.; Kulasooriya, S. A.

    2013-05-01

    Carbohydrates supply carbon sources for microbial activities that contribute to mineral nutrient production in soil. Their role on soil nutrient availability has not yet been properly elucidated. This was studied in forests and cultivated lands in Sri Lanka. Soil organic matter (SOM) fractions affecting carbohydrate availability were also determined. Soil litter contributed to sugars of plant origin (SPO) in croplands. The negative relationship found between clay bound organic matter (CBO) and glucose indicates higher SOM fixation in clay that lower its availability in cultivated lands. In forests, negative relationships between litter and sugars of microbial origin (SMO) showed that litter fuelled microbes to produce sugars. Fucose and glucose increased the availability of Cu, Zn and Mn in forests. Xylose increased Ca availability in cultivated lands. Arabinose, the main carbon source of soil respiration reduced the P availability. This study showed soil carbohydrates and their relationships with mineral nutrients could provide vital information on the availability of limiting nutrients in tropical ecosystems.

  16. Radiation damage in carbon-carbon composites

    International Nuclear Information System (INIS)

    Burchell, T.D.; Eartherly, W.P.; Nelson, G.E.

    1992-01-01

    Graphite and carbon-carbon composite materials are widely used in plasma facing applications in current Tokamak devices such as TFTR and DIIID in the USA, JET, Tore Supra and TEXTOR in Europe, and JT-60U in Japan. Carbon-carbon composites are attractive choices for Tokamak limiters and diverters because of their low atomic number, high thermal shock resistance, high melting point, and high thermal conductivity. Next generation machines such as the International Thermonuclear Experimental Reactor (ITER) will utilize carbon-carbon composites in their first wall and diverter. ITER will be an ignition machine and thus will produce substantial neutron fluences from the D-T fusion reaction. The resultant high energy neutrons will cause carbon atom displacements in the plasma facing materials which will markedly affect their structure and physical properties. The effect of neutron damage on graphite has been studied for over forty years. Recently the effects of neutron irradiation on the fusion relevant graphite GraphNOL N3M was reviewed. In contrast to graphite, relatively little work has been performed to elucidate the effects of neutron irradiation on carbon-carbon composites. The results of our previous irradiation experiments have been published elsewhere. Here the irradiation induced dimensional changes in 1D, 2D, and 3D carbon-carbon composites are reported for fluences up to 4.7 dpa at an irradiation temperature of 600 degree C

  17. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  18. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  19. Hydrogen - the answer to our prayer for low carbon transport?

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Albert; Kershaw, Ian; Vinke, Jan [Ricardo Strategic Consulting GmbH, Muenchen (Germany)

    2008-07-01

    As political, social and economic pressure mounts, the automotive industry needs low carbon solutions - but how do we get there? Despite higher fuel prices and pressure to reduce vehicle CO{sub 2} in many countries, consumers assume limited personal responsibility for reducing carbon emissions from their road transport. The automotive industry is challenged with developing low carbon vehicles without compromise on cost, performance or practicality. The options for reducing CO{sub 2} emissions from road transport range from improved traffic management and driving behaviour, to improved vehicle technologies. Incremental efficiency improvements will be the most cost-effective way of improving powertrains, while economics and availability will continue to limit use of fuel cells, hydrogen and biofuels. We propose an evolutionary route of downsized combustion engines, increasing hybrid electric capability and more biofuel blends, supplemented by lower carbon plug-in electric power for short journeys. The transition to low carbon transport will require policies to encourage consumer demand. (orig.)

  20. Stable carbon, nitrogen and sulfur isotopes in non-carbonate fractions of cold-seep carbonates

    Science.gov (United States)

    Feng, Dong; Peng, Yongbo; Peckmann, Jörn; Roberts, Harry; Chen, Duofu

    2017-04-01

    Sulfate-driven anaerobic oxidation of methane (AOM) supports chemosynthesis-based communities and limits the release of methane from marine sediments. This process promotes the formation of carbonates close to the seafloor along continental margins. The geochemical characteristics of the carbonate minerals of these rocks are increasingly understood, questions remain about the geochemical characteristics of the non-carbonate fractions. Here, we report stable carbon, nitrogen and sulfur isotope patterns in non-carbonate fractions of seep carbonates. The authigenic carbonates were collected from three modern seep provinces (Black Sea, Gulf of Mexico, and South China Sea) and three ancient seep deposits (Marmorito, northern Italy, Miocene; SR4 deposit of the Lincoln Creek Formation and Whiskey Creek, western Washington, USA, Eocene to Oligocene). The δ13C values of non-carbonate fractions range from ˜-25‰ to -80‰ VPDB. These values indicate that fossil methane mixed with varying amounts of pelagic organic matter is the dominant source of carbon in these fractions. The relatively small offset between the δ34S signatures of the non-carbonate fractions and the respective sulfide minerals suggests that locally produced hydrogen sulfide is the main source of sulfur in seep environments. The δ15N values of the non-carbonate fractions are generally lower than the corresponding values of deep-sea sediments, suggesting that organic nitrogen is mostly of a local origin. This study reveals the potential of using δ13C, δ15N, δ34S values to discern seep and non-seep deposits. In cases where δ13Ccarbonate values are only moderately low due to mixing processes and lipid biomarkers have been erased in the course of burial, it is difficult to trace back AOM owing to the lack of other records. This problem is even more pronounced when authigenic carbonate is not available in ancient seep environments. Acknowledgments: The authors thank BOEM and NOAA for their years' support

  1. Carbon sequestration.

    Science.gov (United States)

    Lal, Rattan

    2008-02-27

    Developing technologies to reduce the rate of increase of atmospheric concentration of carbon dioxide (CO2) from annual emissions of 8.6PgCyr-1 from energy, process industry, land-use conversion and soil cultivation is an important issue of the twenty-first century. Of the three options of reducing the global energy use, developing low or no-carbon fuel and sequestering emissions, this manuscript describes processes for carbon (CO2) sequestration and discusses abiotic and biotic technologies. Carbon sequestration implies transfer of atmospheric CO2 into other long-lived global pools including oceanic, pedologic, biotic and geological strata to reduce the net rate of increase in atmospheric CO2. Engineering techniques of CO2 injection in deep ocean, geological strata, old coal mines and oil wells, and saline aquifers along with mineral carbonation of CO2 constitute abiotic techniques. These techniques have a large potential of thousands of Pg, are expensive, have leakage risks and may be available for routine use by 2025 and beyond. In comparison, biotic techniques are natural and cost-effective processes, have numerous ancillary benefits, are immediately applicable but have finite sink capacity. Biotic and abiotic C sequestration options have specific nitches, are complementary, and have potential to mitigate the climate change risks.

  2. Study of factors affecting a combustion method for determining carbon in lithium hydride

    International Nuclear Information System (INIS)

    Barringer, R.E.; Thornton, R.E.

    1975-09-01

    An investigation has been made of the factors affecting a combustion method for the determination of low levels (300 to 15,000 micrograms/gram) of carbon in highly reactive lithium hydride. Optimization of the procedure with available equipment yielded recoveries of 90 percent, with a limit of error (0.95) of +-39 percent relative for aliquants containing 35 to 55 micrograms of carbon (500 to 800 micrograms of carbon per gram of lithium hydride sample). Sample preparation, thermal decomposition of the hydride, final ignition of the carbon, and carbon-measurement steps were studied, and a detailed procedure was developed. (auth)

  3. LANSCE beam current limiter

    International Nuclear Information System (INIS)

    Gallegos, F.R.

    1996-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described

  4. Extracellular enzyme kinetics scale with resource availability

    Science.gov (United States)

    Sinsabaugh, Robert L.; Belnap, Jayne; Findlay, Stuart G.; Follstad Shah, Jennifer J.; Hill, Brian H.; Kuehn, Kevin A.; Kuske, Cheryl; Litvak, Marcy E.; Martinez, Noelle G.; Moorhead, Daryl L.; Warnock, Daniel D.

    2014-01-01

    Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimilation of carbon, nitrogen and phosphorus by diverse aquatic and terrestrial microbial communities (1160 cases). Regression analyses were conducted by habitat (aquatic and terrestrial), enzyme class (hydrolases and oxidoreductases) and assay methodology (low affinity and high affinity substrates) to relate potential reaction rates to substrate availability. Across enzyme classes and habitats, the scaling relationships between apparent Vmax and apparent Km followed similar power laws with exponents of 0.44 to 0.67. These exponents, called elasticities, were not statistically distinct from a central value of 0.50, which occurs when the Km of an enzyme equals substrate concentration, a condition optimal for maintenance of steady state. We also conducted an ecosystem scale analysis of ten extracellular hydrolase activities in relation to soil and sediment organic carbon (2,000–5,000 cases/enzyme) that yielded elasticities near 1.0 (0.9 ± 0.2, n = 36). At the metabolomic scale, the elasticity of extracellular enzymatic reactions is the proportionality constant that connects the C:N:P stoichiometries of organic matter and ecoenzymatic activities. At the ecosystem scale, the elasticity of extracellular enzymatic reactions shows that organic matter ultimately limits effective enzyme binding sites. Our findings suggest that one mechanism by which microbial communities maintain homeostasis is regulating extracellular enzyme expression to optimize the short-term responsiveness of substrate acquisition. The analyses also show that, like elemental stoichiometry, the fundamental attributes of enzymatic reactions can be extrapolated from biochemical to community and ecosystem scales.

  5. Effects of elevated carbon dioxide concentration on growth and N2 fixation of young Robinia pseudoacacia

    International Nuclear Information System (INIS)

    Feng, Z; Flessa, H.; Dyckmans, J.

    2004-01-01

    The effects of elevated carbon dioxide concentration on carbon and nitrogen uptake and nitrogen source partitioning were determined in one year-old locust trees using a dual 13 C and 15 N continuous labelling experiment. Elevated carbon dioxide increased the fraction of new carbon in total carbon, but it did not alter carbon partitioning among plant compartments. Elevated carbon dioxide also increased the fraction of new nitrogen in total nitrogen. This was coupled with a shift in nitrogen source partitioning toward nitrogen fixation. Soil nitrogen uptake was not affected, but nitrogen fixation was markedly increased by elevated carbon dioxide treatment. The increased nitrogen fixation tended to decrease the C/N ratio in the presence of elevated carbon dioxide. Total dry mass of root nodules doubled in response to elevated carbon dioxide, however, this effect was not considered significant because of the great variability in root nodule formation. Overall, it was concluded that the growth of locust trees in an elevated carbon dioxide environment will not primarily be limited by nitrogen availability, giving the R. pseudoacacia species a competitive advantage over non-nitrogen-fixing tree species. It was also suggested that the increase in nitrogen fixation observed in response to elevated carbon dioxide treatment may play a key role in the growth response of forest ecosystems to elevated carbon dioxide by improving nitrogen availability for non-nitrogen-fixing trees. 51 refs., 1 tab., 4 figs

  6. Modeling Carbon Exchange

    Science.gov (United States)

    Sellers, Piers

    2012-01-01

    Model results will be reviewed to assess different methods for bounding the terrestrial role in the global carbon cycle. It is proposed that a series of climate model runs could be scoped that would tighten the limits on the "missing sink" of terrestrial carbon and could also direct future satellite image analyses to search for its geographical location and understand its seasonal dynamics.

  7. Reactor limit control system

    International Nuclear Information System (INIS)

    Rubbel, F.E.

    1982-01-01

    The very extensive use of limitations in the operational field between protection system and closed-loop controls is an important feature of German understanding of operational safety. The design of limitations is based on very large activities in the computational field but mostly on the high level of the plant-wide own commissioning experience of a turnkey contractor. Limitations combine intelligence features of closed-loop controls with the high availability of protection systems. (orig.)

  8. Magnetic limiter for thermonuclear device

    International Nuclear Information System (INIS)

    Shimizu, Masatsugu; Nakamura, Hiroo; Takatsu, Hideyuki; Minato, Akihiko; Fukushima, Yutaka.

    1979-01-01

    Purpose: To decrease X-ray irradiation to coils by constituting magnetic limiters as a laminated structure of a carbon outer layer contacting to plasma and an inner molybdenum layer to thereby reduce braking radiation and secondary X-ray generation. Constitution: Magnetic limiters having a molybdenum substrate laminated with a carbon coating on the front surface is provided to a plasma-confining vacuum container. Fast electrons generated from plasma collide against the magnetic limiter and they are stopped by the carbon layer for suppressing the braking radiation, whereby the braking radiation is ended and the X-rays are decayed by the molybdenum layer. This can decrease the amount of X-rays irradiated on the coil. (Kawakami, Y.)

  9. Carbon-14 waste management

    International Nuclear Information System (INIS)

    Bush, R.P.; Smith, G.M.; White, I.F

    1984-01-01

    Carbon-14 occurs in nature, but is also formed in nuclear reactors. Because of its long half-life and the biological significance of carbon, releases from nuclear facilities could have a significant radiological impact. Waste management strategies for carbon-14 are therefore of current concern. Carbon-14 is present in a variety of waste streams both at reactors and at reprocessing plants. A reliable picture of the production and release of carbon-14 from various reactor systems has been built up for the purposes of this study. A possible management strategy for carbon-14 might be the reduction of nitrogen impurity levels in core materials, since the activation of 14 N is usually the dominant source of carbon-14. The key problem in carbon-14 management is its retention of off-gas streams, particularly in the dissolver off-gas stream at reprocessing plants. Three alternative trapping processes that convert carbon dioxide into insoluble carbonates have been suggested. The results show that none of the options considered need be rejected on the grounds of potential radiation doses to individuals. All exposures should be as low as reasonably achievable, economic and social factors being taken into account. If, on these grounds, retention and disposal of carbon-14 is found to be beneficial, then, subject to the limitations noted, appropriate retention, immobilization and disposal technologies have been identified

  10. Microprobe analysis of carbon gradients

    International Nuclear Information System (INIS)

    Lamothe, M.; Convert, F.

    1987-01-01

    Problems arising in carbon analysis and how they are solved are presented: sample pollution limitation using cold trap and gas jet cleaning sample preparation, carbon content determination and calibration, automation and optimization. Examples given include concentration monitoring. Carbon homogeneity after complete cementation and decarburization by heat treatment. 6 refs, 14 figs [fr

  11. Technical training - places available

    CERN Multimedia

    2012-01-01

    If you would like more information on a course, or for any other inquiry/suggestions, please contact Technical.Training@cern.ch Valeria Perez Reale, Learning Specialist, Technical Programme Coordinator (Tel.: 62424) Eva Stern and Elise Romero, Technical Training Administration (Tel.: 74924) HR Department »Electronics design Next Session Duration Language Availability Comprehensive VHDL for FPGA Design 08-Oct-12 to 12-Oct-12 5 days English 3 places available Foundations of Electromagnetism and Magnet Design (EMAG) 14-Nov-12 to 27-Nov-12 6 days English 20 places available Impacts de la suppression du plomb (RoHS) en électronique 26-Oct-12 to 26-Oct-12 8 hours French 15 places available Introduction to VHDL 10-Oct-12 to 11-Oct-12 2 days English 7 places available LabVIEW Real Time and FPGA 13-Nov-12 to 16-Nov-12 5 days French 5 places available »Mechanical design Next Se...

  12. Proxmox high availability

    CERN Document Server

    Cheng, Simon MC

    2014-01-01

    If you want to know the secrets of virtualization and how to implement high availability on your services, this is the book for you. For those of you who are already using Proxmox, this book offers you the chance to build a high availability cluster with a distributed filesystem to further protect your system from failure.

  13. Towards a more complete SOCCR: Establishing a Coastal Carbon Data Network

    Science.gov (United States)

    Pidgeon, E.; Howard, J.; Tang, J.; Kroeger, K. D.; Windham-Myers, L.

    2015-12-01

    The 2007 State of the Carbon Cycle Report (SOCCR) was highly influential in ensuring components of the carbon cycle were accounted for in national policy and related management. However, while SOCCR detailed the significance of North American coastal wetlands, it was not until recently that leading governments began to fully recognized these ecosystems for their carbon sequestration and storage capacity and hence the significant role coastal ecosystems can play in GHG emission reductions strategies, offset mechanisms, coastal management strategies and climate mitigation policy. The new attention on coastal carbon systems has exposed limitations in terms of data availability and data quality, as well as insufficient knowledge of coastal carbon distributions, characteristics and coastal carbon cycle processes. In addition to restricting scientific progress, lack of comprehensive, comparable, and quality-controlled coastal carbon data is hindering progress towards carbon based conservation and coastal management. To directly address those limitations, we are developing a Global Science and Data Network for Coastal "Blue" Carbon, with support from the Carbon Cycle Interagency Working Group. Goals include: • Improving basic and applied science on carbon and GHG cycling in vegetated coastal ecosystems; • Supporting a coastal carbon and associated GHG data archive for use by the science community, coastal and climate practitioners and other data users; • Building the capacity of coastal carbon stakeholders globally to collect and interpret high quality coastal carbon science and data; • Providing a forum and mechanism to promote exchange and collaboration between scientists and coastal carbon data users globally; and • Outreach activities to ensure the best available data are globally accessible and that science is responsive to the needs of coastal managers and policy-makers.

  14. Technical training - Places available

    CERN Document Server

    2012-01-01

    If you would like more information on a course, or for any other inquiry/suggestions, please contact Technical.Training@cern.ch Valeria Perez Reale, Learning Specialist, Technical Programme Coordinator (Tel.: 62424) Eva Stern and Elise Romero, Technical Training Administration (Tel.: 74924)   Electronics design Next Session Duration Language Availability Certified LabVIEW Associate Developer (CLAD) 06-Dec-12 to 06-Dec-12 1 hour English One more place available Compatibilité électromagnetique (CEM): Applications 23-Nov-12 to 23-Nov-12 3.5 hours English 3 places available Compatibilité électromagnétique (CEM): Introduction 23-Nov-12 to 23-Nov-12 3 hours English 43 places available Effets des Radiations sur les composants et systèmes électroniques 11-Dec-12 to 12-Dec-12 1 day 4 hours French 9 places available LabVIEW for beginners ...

  15. Spectrophotometric Determination of Carbon Disulphide in the Workplace Air

    Directory of Open Access Journals (Sweden)

    V. Pitschmann

    2013-01-01

    Full Text Available This papre describes a simple method of carbon disulphide determination in the air of working environment in the chemical companies and plants after its absorption into aprotic N,N-dimethylformamide solvent. Carbon disulphide absorbed into aprotic solvent was transformed by using ammonium hydroxide on sulphides which were determined by spectrophotometry. 5,5′-Dithiobis(2-nitrobenzoic acid and blue tetrazolium chloride were used as chromogenic sensing reagents. Colour-reducing products were measured at the wavelength of 500, respectively 520 nm. Detection limits for determination of carbon disulphide in the air are 0.2, respectively 0.4 mg·m−3.

  16. Model-based mitigation of availability risks

    NARCIS (Netherlands)

    Zambon, E.; Bolzoni, D.; Etalle, S.; Salvato, M.

    2007-01-01

    The assessment and mitigation of risks related to the availability of the IT infrastructure is becoming increasingly important in modern organizations. Unfortunately, present standards for risk assessment and mitigation show limitations when evaluating and mitigating availability risks. This is due

  17. Model-Based Mitigation of Availability Risks

    NARCIS (Netherlands)

    Zambon, Emmanuele; Bolzoni, D.; Etalle, Sandro; Salvato, Marco

    2007-01-01

    The assessment and mitigation of risks related to the availability of the IT infrastructure is becoming increasingly important in modern organizations. Unfortunately, present standards for Risk Assessment and Mitigation show limitations when evaluating and mitigating availability risks. This is due

  18. Characterization of electron beam evaporated carbon films and compound formation on titanium and silicon

    International Nuclear Information System (INIS)

    Luthin, J.; Linsmeier, C.

    2001-01-01

    The formation of carbon-based mixed materials is unavoidable on the plasma-facing components (e.g. first wall and divertor) of fusion devices when carbon is used together with other materials. On the surfaces of these components very different conditions with respect to particle and energy impact occur. To predict the mixed material formation under these conditions the precise knowledge of the fundamental mechanisms governing these interactions is essential. In this paper we present the results of carbon interaction with titanium and silicon, as model substances for metallic and covalent carbides, during thermal treatment. To perform basic studies of the reactions of carbon with different elements, thin carbon films are produced by electron beam evaporation on the different substrates under UHV conditions. All measurements for chemical analysis are performed using X-ray photoelectron spectroscopy (XPS). We discuss first the properties of the deposited carbon films. The carbon films are characterized on inert gold surfaces and are compared to bulk graphite. Annealing of the carbon films up to 970 K leads to a transition from a disordered carbon network into a graphitic structure. Preparation of carbon films at room temperature on titanium or silicon leads to a limited carbide formation at the carbon/substrate interface. Carbon deposited in excess of several monolayers is present in elementary form. Annealing of the samples leads to complete carbidization consuming the available carbon in both cases. Titanium reacts to TiC and additional substoichiometric carbide, silicon forms SiC with exact stoichiometry. (orig.)

  19. Technical training: places available

    CERN Multimedia

    HR Department

    2007-01-01

    CERN Technical Training: Open Courses (April - June 2007) The following course sessions are currently scheduled in the framework of the CERN Technical Training Programme 2007:   AutoCAD 2006 - niveau 1 (course in French): 25.4.- 26.4.2007 & 2.5. - 3.5.2007 (4 days in 2 modules, 5 places available) AutoCAD 2006 - niveau 1 (course in French): 27.6.- 28.6.2007 & 3.7. - 4.7.2007 (4 days in 2 modules, 5 places available) AutoCAD Mechanical 2006 (course in French) 21.6.-22.6.2007 (2 days, 8 places available) * NEW COURSE* Automate de securite S7 (course in French) 14.5.-16.5.2007 (3 days, 4 places available) * NEW COURSE* Automate de securite S7 (course in French): 9.5.-11.5.2007 (3 days, 4 places available) JCOP - Joint PVSS-JCOP Frameswork (course in English): 21.5.-25.5.2007 (5 days, 12 places available) JCOP - Finite State Machines in the JCOP Frameswork (course in English): 12.6.-14.6.2007 (3 days, 12 places available) LabVIEW Basics 1 (in English): 2.-4.5.2007 (3 days, 7 places ...

  20. High availability IT services

    CERN Document Server

    Critchley, Terry

    2014-01-01

    This book starts with the basic premise that a service is comprised of the 3Ps-products, processes, and people. Moreover, these entities and their sub-entities interlink to support the services that end users require to run and support a business. This widens the scope of any availability design far beyond hardware and software. It also increases the potential for service failure for reasons beyond just hardware and software; the concept of logical outages. High Availability IT Services details the considerations for designing and running highly available ""services"" and not just the systems

  1. Technical Training: Places available

    CERN Multimedia

    Monique Duval

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses: The Joint PVSS JCOP Framework: 14 - 18.6.2004 (5 days) EXCEL 2003 - niveau 2 : 17 & 18.6.2004 (2 jours) MAGNE-04 : Magnétisme pour l'électrotechnique : 6 au 8.7.2004 (3 jours) Technical Training Monique Duval - Tel.74924 technical.training@cern.ch

  2. SSC accelerator availability allocation

    International Nuclear Information System (INIS)

    Dixon, K.T.; Franciscovich, J.

    1991-03-01

    Superconducting Super Collider (SSC) operational availability is an area of major concern, judged by the Central Design Group to present such risk that use of modern engineering tools would be essential to program success. Experience has shown that as accelerator beam availability falls below about 80%, efficiency of physics experiments degrades rapidly due to inability to maintain adequate coincident accelerator and detector operation. For this reason, the SSC availability goal has been set at 80%, even though the Fermi National Accelerator Laboratory accelerator, with a fraction of the SSC's complexity, has only recently approached that level. This paper describes the allocation of the top-level goal to part-level reliability and maintainability requirements, and it gives the results of parameter sensitivity studies designed to help identify the best approach to achieve the needed system availability within funding and schedule constraints. 1 ref., 12 figs., 4 tabs

  3. Nitrous oxide availability.

    Science.gov (United States)

    Murray, M J; Murray, W J

    1980-04-01

    Nitrous oxide (N2O) is marketed as an inhalation anesthetic and as a food ingredient (e.g., whipping cream propellant). In the human, inhalation has been associated with "highs," peripheral nerve damage, mitotic poisoning of bone marrow, psychosis, and mental impairment. Exposure to hypoxemic mixtures has resulted in death. The commercial N2O sources specifically studied were aerosol whipping cream containers (three brands) and 6.5-cm cylinders, or chargers (two brands). The gas content and N2O concentrations of these devices were measured. The aerosol cans, when not shaken, will dispense at least 3 liters of 87 to 90% N2O. Charger misuse may occur when they are substituted for identically designed carbon dioxide (CO2) chargers of a seltzer bottle; 4.3 to 5.0 liters of 93 to 98% N2O is expelled at a controllable rate. The toxicity of these inexpensive N2O products, their high potential for misuse, and the absence of labeling (chargers) argue that their distribution be discontinued.

  4. Global carbon budget 2013

    International Nuclear Information System (INIS)

    Le Quere, C.; Moriarty, R.; Jones, S.D.; Boden, T.A.; Peters, G.P.; Andrew, R.M.; Andres, R.J.; Ciais, P.; Bopp, L.; Maignan, F.; Viovy, N.

    2014-01-01

    Accurate assessment of anthropogenic carbon dioxide (CO 2 ) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates, consistency within and among components, alongside methodology and data limitations. CO 2 emissions from fossil-fuel combustion and cement production (EFF) are based on energy statistics, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover change data, fire activity associated with deforestation, and models. The global atmospheric CO 2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO 2 sink (SOCEAN) is based on observations from the 1990's, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated for the first time in this budget with data products based on surveys of ocean CO 2 measurements. The global residual terrestrial CO 2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models forced by observed climate, CO 2 and land cover change (some including nitrogen-carbon interactions). All uncertainties are reported as ±1, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2003-2012), EFF was 8.6±0.4 GtC yr -1 , ELUC 0.9±0.5 GtC yr -1 , GATM 4.3±0

  5. Atomistic modeling of carbon Cottrell atmospheres in bcc iron

    Science.gov (United States)

    Veiga, R. G. A.; Perez, M.; Becquart, C. S.; Domain, C.

    2013-01-01

    Atomistic simulations with an EAM interatomic potential were used to evaluate carbon-dislocation binding energies in bcc iron. These binding energies were then used to calculate the occupation probability of interstitial sites in the vicinity of an edge and a screw dislocation. The saturation concentration due to carbon-carbon interactions was also estimated by atomistic simulations in the dislocation core and taken as an upper limit for carbon concentration in a Cottrell atmosphere. We obtained a maximum concentration of 10 ± 1 at.% C at T = 0 K within a radius of 1 nm from the dislocation lines. The spatial carbon distributions around the line defects revealed that the Cottrell atmosphere associated with an edge dislocation is denser than that around a screw dislocation, in contrast with the predictions of the classical model of Cochardt and colleagues. Moreover, the present Cottrell atmosphere model is in reasonable quantitative accord with the three-dimensional atom probe data available in the literature.

  6. Methods of soil organic carbon determination in Brazilian savannah soils

    Directory of Open Access Journals (Sweden)

    Juliana Hiromi Sato

    2014-08-01

    Full Text Available Several methods exist for determining soil organic carbon, and each one has its own advantages and limitations. Consequently, a comparison of the experimental results obtained when these methods are employed is hampered, causing problems in the comparison of carbon stocks in soils. This study aimed at evaluating the analytical procedures used in the determination of carbon and their relationships with soil mineralogy and texture. Wet combustion methods, including Walkley-Black, Mebius and Colorimetric determination as well as dry combustion methods, such as Elemental and Gravimetric Analysis were used. Quantitative textural and mineralogical (kaolinite, goethite and gibbsite analyses were also carried out. The wet digestion methods underestimated the concentration of organic carbon, while the gravimetric method overestimated. Soil mineralogy interfered with the determination of carbon, with emphasis on the gravimetric method that was greatly influenced by gibbsite.

  7. Technical training - Places available

    CERN Multimedia

    Davide Vitè

    2006-01-01

    Places available as of 16.5.2006 (May-November course sessions) Technical Training: Places available The number of places available may vary. Please check our Web site to find out the current availability. Places are available on the following courses: Title Hours Date Language ACROBAT 7.0 : Utilisation de fichiers PDF 8 8.05.06 F WORD 2003 - niveau 2 : ECDL 16 22-23.05.06 23-24.05.06 F Comprehensive VHDL for FPGA Design 40 29.05-2.06.06 E C++ Programming Part 2 - Advanced C++ and its Traps and Pitfalls 32 30.05-2.06.06 E ACROBAT 7.0 : Utilisation de fichiers PDF 24 7-9.06.06 E AutoCAD Mechanical 2006 16 13-14.06.06 F CERN EDMS for Local Administrators 16 13-14.06.06 E LabVIEW Base 2 32 27.06-5.07.06 F C++ Programming Part 3 - Templates and the STL (Standard Template Library) 16 27-28.06.06 E C++ Programming Part 4 - Exceptions 8 29.06.06 E FrontPage 2003 - niveau 1 16 29-...

  8. Energy availability in athletes

    DEFF Research Database (Denmark)

    Loucks, Anne B; Kiens, Bente; Wright, Hattie H

    2011-01-01

    Abstract This review updates and complements the review of energy balance and body composition in the Proceedings of the 2003 IOC Consensus Conference on Sports Nutrition. It argues that the concept of energy availability is more useful than the concept of energy balance for managing the diets...... of athletes. It then summarizes recent reports of the existence, aetiologies, and clinical consequences of low energy availability in athletes. This is followed by a review of recent research on the failure of appetite to increase ad libitum energy intake in compensation for exercise energy expenditure...

  9. JUNOS High Availability

    CERN Document Server

    Sonderegger, James; Milne, Kieran; Palislamovic, Senad

    2009-01-01

    Whether your network is a complex carrier or just a few machines supporting a small enterprise, JUNOS High Availability will help you build reliable and resilient networks that include Juniper Networks devices. With this book's valuable advice on software upgrades, scalability, remote network monitoring and management, high-availability protocols such as VRRP, and more, you'll have your network uptime at the five, six, or even seven nines -- or 99.99999% of the time. Rather than focus on "greenfield" designs, the authors explain how to intelligently modify multi-vendor networks. You'll learn

  10. Modeling Complex Time Limits

    Directory of Open Access Journals (Sweden)

    Oleg Svatos

    2013-01-01

    Full Text Available In this paper we analyze complexity of time limits we can find especially in regulated processes of public administration. First we review the most popular process modeling languages. There is defined an example scenario based on the current Czech legislature which is then captured in discussed process modeling languages. Analysis shows that the contemporary process modeling languages support capturing of the time limit only partially. This causes troubles to analysts and unnecessary complexity of the models. Upon unsatisfying results of the contemporary process modeling languages we analyze the complexity of the time limits in greater detail and outline lifecycles of a time limit using the multiple dynamic generalizations pattern. As an alternative to the popular process modeling languages there is presented PSD process modeling language, which supports the defined lifecycles of a time limit natively and therefore allows keeping the models simple and easy to understand.

  11. Preparation of tailored carbons with meso- and micro- porosity via template synthesis route

    Directory of Open Access Journals (Sweden)

    Howard. M. Williams

    2009-02-01

    Full Text Available A low cost templating approach to making non-ordered carbons with a tailored meso/micropore structure is described. A series of mesoporous carbons was prepared from polyfurfuryl alcohol and phenolic resin precursors by a templating route, using a variety of commercially available silica gels as the template material. Carbons were produced with mesopore volumes up to 1 cm3 g-1, mesopore sizes in the range of 4 nm to 8 nm and surface areas in the range of 300 to 700 m2 g-1. These mesoporous carbons were subsequently activated in CO2 to add controlled amounts of microporosity to produce carbons with both a micro and mesoporous structure. Significantly, the activation process did not appreciably change the mesopore size distribution of the carbons. By altering the activation time, it was possible to tailor the micropore: mesopore volume ratios within wide limits.

  12. Technical Training: Places available

    CERN Multimedia

    Monique Duval

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. TECHNICAL TRAINING Monique Duval tel. 74924 technical.training@cern.ch The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses: C++ for Particle Physicists : 8 - 12.3.2004 (6 X 4-hour sessions) Introduction to the CERN EDMS : 9.3.2004 (1 day, free of charge) The EDMS MTF in Practice : 10.3.2004 (morning, free of charge) CLEAN-2002: Working in a Cleanroom : 10.3.2004 (afternoon, free of charge) The CERN EDMS for Engineers : 11.3.2004 (1 day, free of charge) LabVIEW hands-on (E):...

  13. Technical Training: Places available

    CERN Multimedia

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. TECHNICAL TRAINING Monique Duval tel. 74924 technical.training@cern.ch The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses: LabVIEW base 1 : 25 - 27.2.2004(3 jours) Instructor-led WBTechT study or follow-up for Microsoft applications : 26.2.2004 (morning) CLEAN-2002 : Working in a Cleanroom : 10.3.2004 (afternoon - free of charge) C++ for Particle Physicists : 8 - 12.3.2004 (6 X 4-hour sessions) LabVIEW hands-on (E) : 16.3.2004 (afternoon) LabVIEW Basics 1 : 22 - 24.3.2004 ...

  14. Technical Training: Places available

    CERN Multimedia

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. TECHNICAL TRAINING Monique Duval tel. 74924 technical.training@cern.ch The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses: Instructor-led WBTechT study for Microsoft applications :12.2.2004 (morning) Instructor-led WBTechT study or follow-up for Microsoft applications : 19.2.2004 (morning) LabVIEW TestStand I (E) : 23 & 24.2.2004 (2 days) LabVIEW base 1 : 25 - 27.2.2004 (3 jours) Instructor-led WBTechT study or follow-up for Microsoft applications : 19.2.2004 (morning) CLEAN-2002 ...

  15. Technical Training: Places available

    CERN Multimedia

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an "application for training" form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. TECHNICAL TRAINING Monique Duval tel. 74924 technical.training@cern.ch The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses: Instructor-led WBTechT study or follow-up for Microsoft applications : 19.2.2004 (morning) LabVIEW TestStand I (E) : 23 & 24.2.2004 (2 days) LabVIEW base 1 : 25 - 27.2.2004 (3 jours) Instructor-led WBTechT study or follow-up for Microsoft applications : 26.2.2004 (morning) CLEAN-2002 : Working in a Cleanroom : 10.3.2004 (afternoon - free of charge) C++ for Pa...

  16. Technical Training: Places available

    CERN Multimedia

    Davide Vitè

    2006-01-01

    Places available as of 30.5.2006 (June-November course sessions) The number of places available may vary. Please check our Web site to find out the current availability. Places are available on the following courses: Titre Heure Date Langue ACROBAT 7.0 : Utilisation de fichiers PDF 8 6.06.06 F Introduction à InDesign 16 7-8.06.06 F Python: Hands-on Introduction 24 7-9.06.06 E LabVIEW Base 2 16 22-23.06.06 F FileMaker - niveau 1 16 26-27.06.06 F C++ Programming Part 3 - Templates and the STL (Standard Template Library) 16 27-28.06.06 E C++ Programming Part 4 - Exceptions 8 29.06.06 E FrontPage 2003 - niveau 1 16 29-30.06.06 F Manipulation des images 4 6.07.06 F Introduction to Databases and Database Design 16 11-12.07.06 E ACCESS 2003 - Level 1: ECDL 16 13-14.07.06 E-F Design Patterns 16 25-26.07.06 E Introduction à Dreamweaver MX 16 ...

  17. Technical training: Places available

    CERN Multimedia

    Davide Vitè

    2006-01-01

    Places available as of 13.6.2006 (June-December course sessions) The number of places available may vary. Please check our Web site to find out the current availability. Places are available on the following courses: Titre Heure Date Langue LabVIEW Base 2 16 22-23.06.06 F FileMaker - niveau 1 16 26-27.06.06 F C++ Programming Part 3 - Templates and the STL (Standard Template Library) 16 27-28.06.06 E C++ Programming Part 4 - Exceptions 8 29.06.06 E FrontPage 2003 - niveau 1 16 29-30.06.06 F Manipulation des images 4 6.07.06 F Introduction to Databases and Database Design 16 11-12.07.06 E ACCESS 2003 - Level 1: ECDL 16 13-14.07.06 E-F Design Patterns 16 25-26.07.06 E Introduction à Dreamweaver MX 16 26-27.07.06 F ANSYS DesignModeler 16 29-30.08.06 F LabVIEW Basics 1 24 4-6.09.06 E ANSYS Workbench 32 12-15.09.06 F AutoCAD Mechanical 20...

  18. Technical Training: Places available

    CERN Multimedia

    Davide Vitè

    2006-01-01

    Places available as of 9.5.2006 (May-October course sessions) The number of places available may vary. Please check our Web site to find out the current availability. Places are available on the following courses: find out the curren Hours Date Language LabVIEW Application Development 24 15-17.05.06 E LabVIEW Advanced Programming 16 18-19.05.06 E PERL 5: Advanced Aspects 8 18.05.06 E Technique du vide 16 18-19.05.06 F FileMaker - niveau 2 16 11-12.05.06 F WORD 2003 - niveau 2 : ECDL 16 22-23.05.06 F Introduction au VHDL et utilisation du simulateur NCVHDL de CADENCE 16 23-24.05.06 F Comprehensive VHDL for FPGA Design 40 29.05-2.06.06 E C++ Programming Part 2 - Advanced C++ and its Traps and Pitfalls 32 30.05-2.06.06 E Python: Hands-on Introduction 24 7-9.06.06 E AutoCAD Mechanical 2006 16 13-14.06.06 F CERN EDMS for Local Administrators 16 13-14.06.06...

  19. High availability using virtualization

    International Nuclear Information System (INIS)

    Calzolari, Federico; Arezzini, Silvia; Ciampa, Alberto; Mazzoni, Enrico; Domenici, Andrea; Vaglini, Gigliola

    2010-01-01

    High availability has always been one of the main problems for a data center. Till now high availability was achieved by host per host redundancy, a highly expensive method in terms of hardware and human costs. A new approach to the problem can be offered by virtualization. Using virtualization, it is possible to achieve a redundancy system for all the services running on a data center. This new approach to high availability allows the running virtual machines to be distributed over a small number of servers, by exploiting the features of the virtualization layer: start, stop and move virtual machines between physical hosts. The 3RC system is based on a finite state machine, providing the possibility to restart each virtual machine over any physical host, or reinstall it from scratch. A complete infrastructure has been developed to install operating system and middleware in a few minutes. To virtualize the main servers of a data center, a new procedure has been developed to migrate physical to virtual hosts. The whole Grid data center SNS-PISA is running at the moment in virtual environment under the high availability system.

  20. Technical Training: Places available

    CERN Multimedia

    Monique Duval

    2004-01-01

    If you wish to participate in one of the following courses, please discuss with your supervisor and apply electronically directly from the course description pages that can be found on the Web at: http://www.cern.ch/Training/ or fill in an 'application for training' form available from your Divisional Secretariat or from your DTO (Divisional Training Officer). Applications will be accepted in the order of their receipt. The number of places available may vary. Please check our Web site to find out the current availability. Places are available in the following courses: Outlook (short course I) : E-mail : 31.8.2004 (2 hours, morning) Introduction à Outlook : Outlook (short course II) : Calendar, Tasks and Notes : 31.8.2004 (2 hours, afternoon) Instructor-led WBTechT Study or Follow-up for Microsoft Applications : 7.9.2004 (morning) Outlook (short course III) : Meetings and Delegation : 7.9.2004 (2 hours, afternoon) Introduction au VHDL et utilisation du simulateur ...