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Sample records for warmer higher carbon

  1. Warmer winters increase the rhizosphere carbon flow to mycorrhizal fungi more than to other microorganisms in a temperate grassland.

    Science.gov (United States)

    Birgander, Johanna; Rousk, Johannes; Olsson, Pål Axel

    2017-12-01

    A decisive set of steps in the terrestrial carbon (C) cycle is the fixation of atmospheric C by plants and the subsequent C-transfer to rhizosphere microorganisms. With climate change winters are expected to become milder in temperate ecosystems. Although the rate and pathways of rhizosphere C input to soil could be impacted by milder winters, the responses remain unknown. To address this knowledge-gap, a winter-warming experiment was established in a seminatural temperate grassland to follow the C flow from atmosphere, via the plants, to different groups of soil microorganisms. In situ 13 CO2 pulse labelling was used to track C into signature fatty acids of microorganisms. The winter warming did not result in any changes in biomass of any of the groups of microorganisms. However, the C flow from plants to arbuscular mycorrhizal (AM) fungi, increased substantially by winter warming. Saprotrophic fungi also received large amounts of plant-derived C-indicating a higher importance for the turnover of rhizosphere C than biomass estimates would suggest-still, this C flow was unaffected by winter warming. AM fungi was the only microbial group positively affected by winter warming-the group with the closest connection to plants. Winter warming resulted in higher plant productivity earlier in the season, and this aboveground change likely induced plant nutrient limitation in warmed plots, thus stimulating the plant dependence on, and C allocation to, belowground nutrient acquisition. The preferential C allocation to AM fungi was at the expense of C flow to other microbial groups, which were unaffected by warming. Our findings imply that warmer winters may shift rhizosphere C-fluxes to become more AM fungal-dominated. Surprisingly, the stimulated rhizosphere C flow was matched by increased microbial turnover, leading to no accumulation of soil microbial biomass. © 2017 The Authors Global Change Biology Published by John Wiley & Sons Ltd.

  2. A warmer policy for a colder climate: Can China both reduce poverty and cap carbon emissions?

    Energy Technology Data Exchange (ETDEWEB)

    Glomsrød, Solveig; Wei, Taoyuan, E-mail: taoyuan.wei@cicero.uio.no; Aamaas, Borgar; Lund, Marianne T.; Samset, Bjørn H.

    2016-10-15

    Reducing global carbon dioxide (CO{sub 2}) emissions is often thought to be at odds with economic growth and poverty reduction. Using an integrated assessment modeling approach, we find that China can cap CO{sub 2} emissions at 2015 level while sustaining economic growth and reducing the urban-rural income gap by a third by 2030. As a result, the Chinese economy becomes less dependent on exports and investments, as household consumption emerges as a driver behind economic growth, in line with current policy priorities. The resulting accumulated greenhouse gas emissions reduction 2016–2030 is about 60 billion ton (60 Mg) CO{sub 2}e. A CO{sub 2} tax combined with income re-distribution initially leads to a modest warming due to reduction in sulfur dioxide (SO{sub 2}) emissions. However, the net effect is eventually cooling when the effect of reduced CO{sub 2} emissions dominates due to the long-lasting climate response of CO{sub 2}. The net reduction in global temperature for the remaining part of this century is about 0.03 ± 0.02 °C, corresponding in magnitude to the cooling from avoiding one year of global CO{sub 2} emissions. - Highlights: • China can cap CO{sub 2}-emissions at 2015 level without harming economic growth. • Poverty reduction is compatible with policy to cap CO{sub 2} emissions. • Rural poverty reduction financed by CO{sub 2} tax revenue increases domestic consumption. • One year of the global emissions is avoided. • The global mean temperature is reduced by 0.03 (± 0.02) °C.

  3. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes.

    Science.gov (United States)

    Wood, Tana E; Cavaleri, Molly A; Reed, Sasha C

    2012-11-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO(2) ) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  4. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes

    Science.gov (United States)

    Tana Wood; Molly A. Cavaleri; Sasha C. Reed

    2012-01-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO2) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will...

  5. Terrestrial ecosystems under warmer and drier climates

    Science.gov (United States)

    Pan, Y.

    2016-12-01

    Future warmer and drier climates will likely affect many of the world's terrestrial ecosystems. These changes will fundamentally reshape terrestrial systems through their components and across organization levels. However, it is unclear to what extent terrestrial ecosystems would be resilient enough to stay put to increased temperature and water stress by only adjusting carbon fluxes and water balances? And to what extent it would reach the thresholds at which terrestrial ecosystems were forced to alter species compositions and ecosystem structures for adapting to newer climates? The energy balance of terrestrial ecosystems link thermal and water conditions to defines terrestrial carbon processes and feedbacks to climate, which will inevitably change under warmer and drier climates. Recent theoretical studies provide a new framework, suggesting that terrestrial ecosystems were capable of balancing costs of carbon gain and water transport to achieve optimums for functioning and distribution. Such a paradigm is critical for understanding the dynamics of future terrestrial ecosystems under climate changes, and facilitate modeling terrestrial ecosystems which needs generalized principles for formulating ecosystem behaviors. This study aims to review some recent studies that explore responses of terrestrial ecosystems to rather novel climate conditions, such as heat-induced droughts, intending to provide better comprehension of complex carbon-water interactions through plants to an ecosystem, and relevant factors that may alleviate or worsen already deteriorated climates such as elevated CO2 and soil conditions.

  6. Agroecosystem productivity in a warmer and CO2 enriched atmosphere

    Science.gov (United States)

    Bernacchi, Carl; Köhler, Iris; Ort, Donald; Long, Steven; Clemente, Thomas

    2017-04-01

    A number of in-field manipulative experiments have been conducted that address the response of key ecosystem services of major agronomic species to rising CO2. Global warming, however, is inextricably linked to rising greenhouse gases in general, of which CO2 is the most dominant. Therefore, agroecosystem functioning in future conditions requires an understanding of plant responses to both rising CO2 and increased temperatures. Few in-field manipulative experiments have been conducted that supplement both heating and CO2 above background concentrations. Here, the results of six years of experimentation using a coupled Free Air CO2 Enrichment (FACE) technology with variable output infrared heating arrays are reported. The manipulative experiment increased temperatures (+ 3.5˚ C) and CO2 (+ 200 μmol mol-1) above background levels for on two major agronomic crop species grown throughout the world, Zea mays (maize) and Glycine max (soybean). The first phase of this research addresses the response of plant physiological parameters to growth in elevated CO2 and warmer temperatures for maize and soybean grown in an open-air manipulative experiment. The results show that any increase in ecosystem productivity associated with rising CO2 is either similar or is offset by growth at higher temperatures, inconsistent with the perceived benefits of higher CO2 plus warmer temperatures on agroecosystem productivity. The second phase of this research addresses the opportunity to genetically modify soybean to allow for improved productivity under high CO2 and warmer temperatures by increasing a key photosynthetic carbon reduction cycle enzyme, SPBase. The results from this research demonstrates that manipulation of the photosynthetic pathway can lead to higher productivity in high CO2 and temperature relative to the wild-type control soybean. Overall, this research advances the understanding of the physiological responses of two major crops, and the impact on ecosystem services

  7. Warmer night-time temperature promotes microbial heterotrophic activity and modifies stream sediment community.

    Science.gov (United States)

    Freixa, Anna; Acuña, Vicenç; Casellas, Maria; Pecheva, Stoyana; Romaní, Anna M

    2017-09-01

    Diel temperature patterns are changing because of global warming, with higher temperatures being predicted to be more pronounced at night. Biological reactions are temperature dependent, with some occurring only during the daylight hours (e.g., light photosynthesis) and other during the entire day (e.g., respiration). Consequently, we expect the modification of daily temperature cycles to alter microbial biological reactions in stream sediments. Here, we aimed to study the effect of warming and changes of the diel temperature patterns on stream sediment biofilm functions tied to organic carbon decomposition, as well as on biofilm meiofaunal community structure. We performed an eight-week experiment with 12 artificial streams subjected to three different diel temperature patterns: warming, warmer nights and control. Significant effects of warming on biofilm function and structure were mainly detected in the long term. Our results showed that warming altered biofilm function, especially in the warmer nights' treatment, which enhanced β-glucosidase enzyme activity. Interestingly, clear opposite diel patterns were observed for dissolved organic carbon and β-glucosidase activity, suggesting that, at night, sediment bacteria quickly consume the input of photosynthetic dissolved organic carbon labile compounds created during light-time. The biofilm structure was also altered by warming, as both warming and warmer night treatments enhanced copepod abundance and diminished abundances of turbellaria and nematodes, which, in turn, controlled bacterial, algal and ciliate communities. Overall, we conclude that warming has strong effect on sediment biofilm structure and enhanced microbial organic matter degradation which might, consequently, affect higher trophic levels and river carbon cycling. © 2017 John Wiley & Sons Ltd.

  8. Climate and Climate Impact Scenarios for Europe in a Warmer World.

    Science.gov (United States)

    Lough, J. M.; Wigley, T. M. L.; Palutikof, J. P.

    1983-10-01

    Scenarios for Europe in a warmer world, such as may result from increased atmospheric carbon dioxide levels, have been constructed using the early 20th century warming as an analogue. Mean temperature, Precipitation and pressure patterns for the period 1934-53 were compared with those for 1901-20. These are the warmest and cooler twenty-year periods this century based on Northern Hemisphere annual mean surface air temperature data, differing by 0.4°C. The climate scenarios show marked subregional scale differences from season to season, and individual season scenarios often show little similarity to the annual scenario. Temperature scenarios show warming for the annual mean and for spring, summer and autumn. The largest positive changes are found in higher latitudes. Winters over a large part of Europe are actually cooler and show greater interannual variability during the warmer period. These changes appear to be associated with a greater frequency of blocking activity. Precipitation changes occur in both directions in all seasons. There is, however, an overall tendency for spring and summer to be drier and autumn and winter to be wetter.The climate scenarios are used to construct scenarios of the impact of a global warming on energy consumption and agriculture. Cooler winters alone would imply greater energy demand for space heating, but this is largely offset by warmer temperatures in spring and autumn which reduce the length of the heating season. Increased temperature variability combined with a general cooling during winter over north and northwestern Europe suggests a greater frequency of severe winters, and thus larger fluctuations in the demand for heating energy. The impact on agriculture is difficult to assess because of the complexity of crop-climate relationships and because of the importance of nonclimatic factors associated with technological change and, perhaps, with enhanced photosynthesis due to increased carbon dioxide concentrations. In

  9. Comparison of fluid warmer performance during simulated clinical conditions.

    Science.gov (United States)

    Patel, N; Smith, C E; Pinchak, A C

    1995-07-01

    The study evaluated the warming ability and flow rates associated with four fluid warming devices during pressure driven infusion and during wide open gravity driven roller clamp infusion. Warmers tested were the Astotherm, Flotem IIe, Level 1 System 250 and a modified cardioplegia heat exchanger. Fluids tested were crystalloid, red cells diluted with 200 ml, 0.9% saline, and undiluted red cells. The volume of fluid and outlet temperatures (point where i.v. tubing would be attached to the patient) were measured for each fluid and compared among warmers for each flow rate condition. For pressure driven infusion of red cells and crystalloid, the System 250, and modified heat exchanger delivered warmer fluids (33-35 degrees C) at higher flow rates (160-740 ml.min-1) than the Astotherm and Flotem (23-31 degrees C, 44-268 ml.min-1, P 32 degrees C) in warming crystalloid and red cells at pressure driven flow rates. Only the System 250 warmed red cells > 35 degrees C at gravity driven flow rates. The Flotem and Astotherm were not effective in warming rapidly infused solutions. None of the warmers tested was able to deliver fluids at normothermia (> 36.5 degrees C).

  10. Slower snowmelt in a warmer world

    Science.gov (United States)

    Musselman, Keith; Clark, Martyn; Liu, Changhai; Ikeda, Kyoko; Rasmussen, Roy

    2017-04-01

    There is general consensus that projected warming will cause earlier snowmelt, but how the melt rates of seasonal snow-cover will respond to climate change is poorly known. We present snowpack observations from western North America that show that shallower snowpack melts earlier and at lower rates than deeper, later-lying snow-cover. The observations provide the context for a hypothesis that reduced snowpack in a warmer world will melt at lower rates. We test this hypothesis using high-resolution Weather Research and Forecasting model simulations over much of North America for a historical decade (2000-2010), verified against snowpack and precipitation observations, and then re-run with a pseudo-global-warming technique. We find that the fraction of meltwater volume produced at high snowmelt rates is greatly reduced in a warmer climate. The reduction is caused by a contraction of the snowmelt season to a time of lower available energy, reducing by as much as 64% the snow-covered area exposed to energy sufficient to drive high snowmelt rates. The results have important implications on soil moisture deficits, vegetation stress and streamflow declines over large areas of the world.

  11. Growth Rate Potential of Juvenile Sockeye Salmon in Warmer and Cooler Years on the Eastern Bering Sea Shelf

    Directory of Open Access Journals (Sweden)

    Edward V. Farley

    2009-01-01

    Full Text Available A spatially explicit bioenergetics model was used to predict juvenile sockeye salmon Oncorhynchus nerka growth rate potential (GRP on the eastern Bering Sea shelf during years with cooler and warmer spring sea surface temperatures (SSTs. Annual averages of juvenile sockeye salmon GRP were generally lower among years with cooler SSTs and generally higher in offshore than nearshore regions of the eastern Bering Sea shelf during years with warmer SSTs. Juvenile sockeye salmon distribution was significantly (P<.05 related to GRP and their prey densities were positively related to spring SST (P<.05. Juvenile sockeye salmon GRP was more sensitive to changes in prey density and observed SSTs during years when spring SSTs were warmer (2002, 2003, and 2005. Our results suggest that the pelagic productivity on the eastern Bering Sea shelf was higher during years with warmer spring SSTs and highlight the importance of bottom-up control on the eastern Bering Sea ecosystem.

  12. Evaluation of fluid warmer safety using hemorheologic analysis with outdated human blood.

    Science.gov (United States)

    Kim, Hee Jung; Yoo, Sung Mook; Chung, Jae Ho; Kim, Tae Sik; Lee, Sung Ho; Son, Ho Sung

    2016-01-01

    A newly developed fluid warmer (ThermoSens®) has a direct blood warming plate, which can result in hemolysis or red blood cell injury during heating. Therefore, to evaluate the safety of heating blood products with a fluid warmer, we conducted laboratory tests to study hemolysis and erythrocyte rheology. We used outdated human blood taken from a Korean blood bank. Packed red blood cells mixed with 100 mL isotonic saline was passed through the fluid warmer. Blood flow was achieved by either gravity or 300 mmHg pressure. Blood samples were analyzed before and after heating for hemolysis marker and erythrocyte rheology parameters. The temperatures at the outlet were higher than 38°C at gravity and 300 mmHg pressure, respectively. There were no significant differences in hemolysis markers (hemoglobin, hematocrit, lactate dehydrogenase, and plasma free hemoglobin) or erythrocyte rheology (deformability, disaggregating shear stress, and aggregation index) between before and after heating (p >  0.05) except LDH at gravity (p = 0.0001). The ThermoSens® fluid warmer caused no erythrocyte injury or negative effects on rheology during heating. Regarding medical device development, hemorheologic analysis can be useful for safety evaluation of medical devices that directly contact blood for temperature modulation.

  13. Climate and climate impact scenarios for Europe in a warmer world

    Energy Technology Data Exchange (ETDEWEB)

    Lough, J.M.; Wigley, T.M.L.; Palutikof, J.P.

    1983-10-01

    Scenarios for Europe in a warmer world, such as may result from increased atmospheric carbon dioxide levels, have been constructed using the early 20th century warming as an analogue. The climate scenarios are used to construct scenarios of the impact of a global warming on energy consumption and agriculture. Cool winters alone would imply greater energy demand for space heating, but this is largely offset by warmer temperatures in spring and autumn which reduce the length of the heating season. Increased temperature variability combined with a general cooling during winter over north and northwestern Europe suggests a greater frequency of severe winters, and thus larger fluctuations in the demand for heating energy. The impact on agriculture is difficult to assess because of the complexity of crop-climate relationships and because of the importance of nonclimatic factors associated with technological change and perhaps, with enhanced photosynthesis due to increased carbon dioxide concentrations. In northern latitudes, the increase in the length of the growing season would appear to be favorable for agriculture, but warmer summers, drier springs and wetter autumns would be less favorable. A specific study was made of the effect of two different climate scenarios on crop yields in England and Wales with regression models constructed using a principal components regression technique. Most crops showed a decrease in yield for both warm-world scenarios, with largest decreases for hay yield and least effect on wheat yield. A similar regression analysis of French wine-quality showed an improvement in the quality of Bordeaux and Champagne in a warmer world. 52 references, 5 figures, 2 tables.

  14. Active carbon supported molybdenum carbides for higher alcohols synthesis from syngas

    DEFF Research Database (Denmark)

    Wu, Qiongxiao; Chiarello, Gian Luca; Christensen, Jakob Munkholt

    This work provides an investigation of the high pressure CO hydrogenation to higher alcohols on K2CO3 promoted active carbon supported molybdenum carbide. Both activity and selectivity to alcohols over supported molybdenum carbides increased significantly compared to bulk carbides in literatures....... The optimal loadings of both molybdenum carbide and the K2CO3 promoter on active carbon have been investigated. The catalysts were characterized using BET surface area measurements, transmission electron microscopy and X-ray diffraction. Additionally, in-situ X-ray diffraction and in-situ X-ray absorption...

  15. Water cycle dynamic increases resilience of vegetation under higher atmospheric carbon dioxide concentration

    Science.gov (United States)

    Lemordant, L. A.; Gentine, P.; Stéfanon, M.; Drobinski, P. J.; Fatichi, S.

    2015-12-01

    Plant stomata couple the energy, water and carbon cycles. Photosynthesis requires stomata to open to take up carbon dioxide. In the process water vapor is released as transpiration. As atmospheric CO2 concentration rises, for the same amount of CO2 uptake, less water vapor is transpired, translating into higher water use efficiency. Reduced water vapor losses will increase soil water storage if the leaf area coverage remains similar. This will in turn alter the surface energy partitioning: more heat will be dissipated as sensible heat flux, resulting in possibly higher surface temperatures. In contrast with this common hypothesis, our study shows that the water saved during the growing season by increased WUE can be mobilized by the vegetation and help reduce the maximum temperature of mid-latitude heat waves. The large scale meteorological conditions of 2003 are the basis of four regional model simulations coupling an atmospheric model to a surface model. We performed two simulations with respectively 2003 (CTL) and 2100 (FUT) atmospheric CO2 applied to both the atmospheric and surface models. A third (RAD) and a fourth (FER) simulations are run with 2100 CO2 concentration applied to respectively the atmospheric model only and the surface model only. RAD investigates the impact of the radiative forcing, and FER the response to vegetation CO2 fertilization. Our results show that the water saved through higher water use efficiency during the growing season enabled by higher atmospheric carbon dioxide concentrations helps the vegetation to cope during severe heat and dryness conditions in the summer of mid-latitude climate. These results demonstrate that consideration of the vegetation carbon cycle is essential to model the seasonal water cycle dynamic and land-atmosphere interactions, and enhance the accuracy of the model outputs especially for extreme events. They also have important implications for the future of agriculture, water resources management, ecosystems

  16. Higher Order Chemistry Models in the CFD Simulation of Laser-Ablated Carbon Plumes

    Science.gov (United States)

    Scott, C. D.; Greendyke, R. B.; Creel, J. R.; Payne, B. T.

    2005-01-01

    . e C6 studies had yielded a far greater propagation in previous studies. In addition, chemical species development with the C30 model indicates that many higher order carbon species are produced outside of the plume proper (indicated by plotting contours of the background argon concentrations in Fig. 3) - this result was not observed in previous studies. In fact, some species primarily occurred outside of the plume itself - as shown for C27 in Fig. 4 when it is compared to Fig. 3. It could be asserted that this has occurred because all of the C27 in the plume had already been consumed in the formation of C30, but this does not seem to be indicated over time. Several other factors that arose in the previous studies have also been made more clear by the use of the higher order chemical models - one being that the use of c6 as an indicator species was mistaken. C6 is the only carbon species in the previous studies that was not injected into the flowfield as a boundary condition; it was therefore hoped that this species would provide insight into the formation of higher order carbon species for comparison to full SWNT production. But, when the plot of total mass in the plume is examined on a species by species basis in Fig. 5, it is seen that Cg was a fairly insignificant contributor to the total carbon mass in the plume and would not provide information on higher order carbon formation. the thermophysical characteristics of the carbon plume as well as simulate the carbon plume using the reduced SWNT model to provide an even better simulation of full chemistry effects upon plume propagation.

  17. Climate warming shifts carbon allocation from stemwood to roots in calcium-depleted spruce forests

    Science.gov (United States)

    Andrei G. ​Lapenis; Gregory B. Lawrence; Alexander Heim; Chengyang Zheng; Walter. Shortle

    2013-01-01

    Increased greening of northern forests, measured by the Normalized Difference Vegetation Index (NDVI), has been presented as evidence that a warmer climate has increased both net primary productivity (NPP) and the carbon sink in boreal forests. However, higher production and greener canopies may accompany changes in carbon allocation that favor foliage or fine roots...

  18. Rhizosphere bacterial carbon turnover is higher in nucleic acids than membrane lipids: implications for understanding soil carbon cycling

    Science.gov (United States)

    Malik, Ashish A.; Dannert, Helena; Griffiths, Robert I.; Thomson, Bruce C.; Gleixner, Gerd

    2015-01-01

    Using a pulse chase 13CO2 plant labeling experiment we compared the flow of plant carbon into macromolecular fractions of rhizosphere soil microorganisms. Time dependent 13C dilution patterns in microbial cellular fractions were used to calculate their turnover time. The turnover times of microbial biomolecules were found to vary: microbial RNA (19 h) and DNA (30 h) turned over fastest followed by chloroform fumigation extraction-derived soluble cell lysis products (14 days), while phospholipid fatty acids (PLFAs) had the slowest turnover (42 days). PLFA/NLFA 13C analyses suggest that both mutualistic arbuscular mycorrhizal and saprophytic fungi are dominant in initial plant carbon uptake. In contrast, high initial 13C enrichment in RNA hints at bacterial importance in initial C uptake due to the dominance of bacterial derived RNA in total extracts of soil RNA. To explain this discrepancy, we observed low renewal rate of bacterial lipids, which may therefore bias lipid fatty acid based interpretations of the role of bacteria in soil microbial food webs. Based on our findings, we question current assumptions regarding plant-microbe carbon flux and suggest that the rhizosphere bacterial contribution to plant assimilate uptake could be higher. This highlights the need for more detailed quantitative investigations with nucleic acid biomarkers to further validate these findings. PMID:25914679

  19. Rhizosphere bacterial carbon turnover is higher in nucleic acids than membrane lipids: implications for understanding soil carbon cycling

    Directory of Open Access Journals (Sweden)

    Ashish A. Malik

    2015-04-01

    Full Text Available Using a pulse-chase 13CO2 plant labeling experiment we compared the flow of plant carbon into macromolecular fractions of root-associated soil microorganisms. Time dependent 13C dilution patterns in microbial cellular fractions were used to calculate their turnover time. The turnover times of microbial biomolecules were found to vary: microbial RNA (19 h and DNA (30 h turned over fastest followed by chloroform fumigation extraction-derived soluble cell lysis products (14 d, while phospholipid fatty acids (PLFAs had the slowest turnover (42 d. PLFA/NLFA 13C analyses suggest that both mutualistic arbuscular mycorrhizal and saprophytic fungi are dominant in initial plant carbon uptake. In contrast, high initial 13C enrichment in RNA hints at bacterial importance in initial C uptake due to the dominance of bacterial derived RNA in total extracts of soil RNA. To explain this discrepancy, we observed low renewal rate of bacterial lipids, which may therefore bias lipid fatty acid based interpretations of the role of bacteria in soil microbial food webs. Based on our findings, we question current assumptions regarding plant-microbe carbon flux and suggest that the rhizosphere bacterial contribution to plant assimilate uptake could be higher. This highlights the need for more detailed quantitative investigations with nucleic acid biomarkers to further validate these findings.

  20. Warmer climates boost cyanobacterial dominance in shallow lakes

    NARCIS (Netherlands)

    Kosten, S.; Huszar, V.M.; Bécares, E.; Costa, S.; Donk, van E.; Hansson, L.; Lurling, M.F.L.L.W.

    2012-01-01

    Dominance by cyanobacteria hampers human use of lakes and reservoirs worldwide. Previous studies indicate that excessive nutrient loading and warmer conditions promote dominance by cyanobacteria, but evidence from global scale field data has so far been scarce. Our analysis, based on a study of 143

  1. Warmer and Wetter Soil Stimulates Assimilation More than Respiration in Rainfed Agricultural Ecosystem on the China Loess Plateau: The Role of Partial Plastic Film Mulching Tillage.

    Science.gov (United States)

    Gong, Daozhi; Hao, Weiping; Mei, Xurong; Gao, Xiang; Liu, Qi; Caylor, Kelly

    2015-01-01

    Effects of agricultural practices on ecosystem carbon storage have acquired widespread concern due to its alleviation of rising atmospheric CO2 concentrations. Recently, combining of furrow-ridge with plastic film mulching in spring maize ecosystem was widely applied to boost crop water productivity in the semiarid regions of China. However, there is still limited information about the potentials for increased ecosystem carbon storage of this tillage method. The objective of this study was to quantify and contrast net carbon dioxide exchange, biomass accumulation and carbon budgets of maize (Zea maize L.) fields under the traditional non-mulching with flat tillage (CK) and partial plastic film mulching with furrow-ridge tillage (MFR) on the China Loess Plateau. Half-hourly net ecosystem CO2 exchange (NEE) of both treatments were synchronously measured with two eddy covariance systems during the growing seasons of 2011 through 2013. At same time green leaf area index (GLAI) and biomass were also measured biweekly. Compared with CK, the warmer and wetter (+1.3°C and +4.3%) top soil at MFR accelerated the rates of biomass accumulation, promoted greater green leaf area and thus shortened the growing seasons by an average value of 10.4 days for three years. MFR stimulated assimilation more than respiration during whole growing season, resulting in a higher carbon sequestration in terms of NEE of -79 gC/m2 than CK. However, after considering carbon in harvested grain (or aboveground biomass), there is a slight higher carbon sink (or a stronger carbon source) in MFR due to its greater difference of aboveground biomass than that of grain between both treatments. These results demonstrate that partial plastic film mulched furrow-ridge tillage with aboveground biomass exclusive of grain returned to the soil is an effective way to enhance simultaneously carbon sequestration and grain yield of maize in the semiarid regions.

  2. Co-cultivation of microalgae and nitrifiers for higher biomass production and better carbon capture.

    Science.gov (United States)

    Bilanovic, Dragoljub; Holland, Mark; Starosvetsky, Jeanna; Armon, Robert

    2016-11-01

    The aim of this work was to study co-cultivation of nitrifiers with microalgae as a non-intrusive technique for selective removal of oxygen generated by microalgae. Biomass concentration was, at least, 23% higher in mixed-cultures where nitrifiers kept the dissolved oxygen concentration below 9.0μLL(-1) than in control Chlorella vulgaris axenic-cultures where the concentration of dissolved oxygen was higher than 10.0μLL(-1). This approach to eliminating oxygen inhibition of microalgal growth could become the basis for the development of advanced microalgae reactors for removal of CO2 from the atmosphere, and concentrated CO2 streams. CO2 sequestration would become a chemically and geologically safer and environmentally more sound technology provided it uses microalgal, or other biomass, instead of CO2, for carbon storage. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Role of Aquaporins in Determining Carbon and Nitrogen Status in Higher Plants

    Directory of Open Access Journals (Sweden)

    Limin Gao

    2018-01-01

    Full Text Available Aquaporins (AQPs are integral membrane proteins facilitating the transport of water and some small neutral molecules across cell membranes. In past years, much effort has been made to reveal the location of AQPs as well as their function in water transport, photosynthetic processes, and stress responses in higher plants. In the present review, we paid attention to the character of AQPs in determining carbon and nitrogen status. The role of AQPs during photosynthesis is characterized as its function in transporting water and CO2 across the membrane of chloroplast and thylakoid; recalculated results from published studies showed that over-expression of AQPs contributed to 25% and 50% increases in stomatal conductance (gs and mesophyll conductance (gm, respectively. The nitrogen status in plants is regulated by AQPs through their effect on water flow as well as urea and NH4+ uptake, and the potential role of AQPs in alleviating ammonium toxicity is discussed. At the same time, root and/or shoot AQP expression is quite dependent on both N supply amounts and forms. Future research directions concerning the function of AQPs in regulating plant carbon and nitrogen status as well as C/N balance are also highlighted.

  4. Selective self-excitation of higher vibrational modes of graphene nano-ribbons and carbon nanotubes through magnetomotive instability

    OpenAIRE

    Nordenfelt, Anders

    2011-01-01

    We demonstrate theoretically the feasibility of selective self-excitation of higher-mode flexural vibrations of graphene nano-ribbons and carbon nanotubes by the means of magnetomotive instability. Apart from the mechanical resonator, the device consists only of a constant voltage source, an inductor, a capacitor, a gate electrode and a constant magnetic field. Numerical simluations were performed on both graphene and carbon nanotubes displaying an overall similar behaviour, but with some dif...

  5. Does warmer China land attract more super typhoons?

    Science.gov (United States)

    Xu, Xiangde; Peng, Shiqiu; Yang, Xiangjing; Xu, Hongxiong; Tong, Daniel Q; Wang, Dongxiao; Guo, Yudi; Chan, Johnny C L; Chen, Lianshou; Yu, Wei; Li, Yineng; Lai, Zhijuan; Zhang, Shengjun

    2013-01-01

    Accurate prediction of where and when typhoons (or named hurricanes which form over the North Atlantic Ocean) will make landfall is critical to protecting human lives and properties. Although the traditional method of typhoon track prediction based on the steering flow theory has been proven to be an effective way in most situations, it slipped up in some cases. Our analysis of the long-term Chinese typhoon records reveals that typhoons, especially super typhoons (those with maximum sustained surface winds of greater than 51 ms(-1)), have a trend to make landfalls toward warmer land in China over the past 50 years (1960-2009). Numerical sensitivity experiments using an advanced atmospheric model further confirm this finding. Our finding suggests an alternative approach to predict the landfall tracks of the most devastating typhoons in the southeastern China.

  6. Heterogeneous carbon nano-tube window layer with higher sheet resistance improve the solar cell performance

    Science.gov (United States)

    Jolson Singh, Khomdram; Jayenta Singh, Thokchom; Chettri, Dhanu; Sarkar, Subir kumar

    2017-06-01

    The heterogeneous Carbon Nano-Tube (CNT) layers deposited on the window surface of solar cells that allow better charge carrier collection was numerically analyzed and studied in modern TCAD tools. The quantum efficiency(EQE) as well as power conversion efficiency (η) were found to be improved significantly based on the light transmission capabilities of the CNT layer. Two CNT network models using experimental sheet resistance values of 75 Ω/□ and 128 Ω/□ as a top conducting layer in a GaAs solar cell were compared. It is found that the CNT networks allow for a greater area of charge collection as well as serve as a lower resistance path for charge carriers with minimum voltage loss to travel to the top contact. This model thus significantly improve the η up to 30% under AM0 with more than 90% EQE. The effect of cell width varying starting from 200 μm to 4000 μm with CNT top layer on Jsc, Voc and Pmax parameters were studied and found that these parameters remain almost constant irrespective of cell width. This work thus shown that a thin CNT top layers of lower sheet resistance with a higher light transmission can greatly improve the efficiency of solar cells.

  7. Higher climatological temperature sensitivity of soil carbon in cold than warm climates

    Science.gov (United States)

    Koven, Charles D.; Hugelius, Gustaf; Lawrence, David M.; Wieder, William R.

    2017-11-01

    The projected loss of soil carbon to the atmosphere resulting from climate change is a potentially large but highly uncertain feedback to warming. The magnitude of this feedback is poorly constrained by observations and theory, and is disparately represented in Earth system models (ESMs). To assess the climatological temperature sensitivity of soil carbon, we calculate apparent soil carbon turnover times that reflect long-term and broad-scale rates of decomposition. Here, we show that the climatological temperature control on carbon turnover in the top metre of global soils is more sensitive in cold climates than in warm climates and argue that it is critical to capture this emergent ecosystem property in global-scale models. We present a simplified model that explains the observed high cold-climate sensitivity using only the physical scaling of soil freeze-thaw state across climate gradients. Current ESMs fail to capture this pattern, except in an ESM that explicitly resolves vertical gradients in soil climate and carbon turnover. An observed weak tropical temperature sensitivity emerges in a different model that explicitly resolves mineralogical control on decomposition. These results support projections of strong carbon-climate feedbacks from northern soils and demonstrate a method for ESMs to capture this emergent behaviour.

  8. In situ removal of carbon contamination from a chromium-coated mirror: ideal optics to suppress higher-order harmonics in the carbon K-edge region

    Energy Technology Data Exchange (ETDEWEB)

    Toyoshima, Akio; Kikuchi, Takashi; Tanaka, Hirokazu [KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Mase, Kazuhiko, E-mail: mase@post.kek.jp; Amemiya, Kenta [KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); SOKENDAI (The Graduate University for Advanced Studies), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)

    2015-09-26

    Carbon contamination of a chromium-coated mirror was removed by exposure to oxygen activated with non-monochromated synchrotron radiation. Higher-order harmonics of the chromium-coated mirror are much smaller than those of a gold-coated mirror in the carbon K-edge region. Carbon-free chromium-coated optics are ideal in the carbon K-edge region (280–330 eV) because the reflectivity of first-order light is larger than that of gold-coated optics while the second-order harmonics (560–660 eV) are significantly suppressed by chromium L-edge and oxygen K-edge absorption. Here, chromium-, gold- and nickel-coated mirrors have been adopted in the vacuum ultraviolet and soft X-ray branch beamline BL-13B at the Photon Factory in Tsukuba, Japan. Carbon contamination on the chromium-coated mirror was almost completely removed by exposure to oxygen at a pressure of 8 × 10{sup −2} Pa for 1 h under irradiation of non-monochromated synchrotron radiation. The pressure in the chamber recovered to the order of 10{sup −7} Pa within a few hours. The reflectivity of the chromium-coated mirror of the second-order harmonics in the carbon K-edge region (560–660 eV) was found to be a factor of 0.1–0.48 smaller than that of the gold-coated mirror.

  9. Soil nitrogen gas emissions increase considerably in warmer forest soils

    Science.gov (United States)

    Kitzler, Barbara; Schindlbacher, Andreas; Jandl, Robert; Zechmeister-Boltenstern, Sophie

    2015-04-01

    Climate change will likely modify ecosystem properties and processes and therefore impact nitrogen (N) dynamics of forest soils. To elucidate the effect of warming and drought conditions on the nitrogen gas emissions we measured N2O and NO fluxes from the soil warming experiment Achenkirch, a spruce-fir-beech forest soil in the North Tyrolean limestone Alps in Austria. The uppermost layer of the soil was warmed (4°C) by heating cables during the snow-free seasons. Roofs were installed during 25 days in July/August 2008 and 2009 to simulate drought conditions. Gas sampling was conducted biweekly with static chambers (N2O). Gas concentrations were detected by GC. Nitric oxide fluxes were measured by an automatic dynamic chamber system on an hourly basis. In our study the emissions of N2O were increased by up to 73 % at warmed plots, and we observed a temporary increase following first rain. However N2O emissions of the drought affected plots remained depressed for more than two months after roof removal. Nitric oxide fluxes were increased considerably during dry periods and under warmer conditions.

  10. Survival of Norway spruce remains higher in mixed stands under a dryer and warmer climate.

    Science.gov (United States)

    Neuner, Susanne; Albrecht, Axel; Cullmann, Dominik; Engels, Friedrich; Griess, Verena C; Hahn, W Andreas; Hanewinkel, Marc; Härtl, Fabian; Kölling, Christian; Staupendahl, Kai; Knoke, Thomas

    2015-02-01

    Shifts in tree species distributions caused by climatic change are expected to cause severe losses in the economic value of European forestland. However, this projection disregards potential adaptation options such as tree species conversion, shorter production periods, or establishment of mixed species forests. The effect of tree species mixture has, as yet, not been quantitatively investigated for its potential to mitigate future increases in production risks. For the first time, we use survival time analysis to assess the effects of climate, species mixture and soil condition on survival probabilities for Norway spruce and European beech. Accelerated Failure Time (AFT) models based on an extensive dataset of almost 65,000 trees from the European Forest Damage Survey (FDS)--part of the European-wide Level I monitoring network--predicted a 24% decrease in survival probability for Norway spruce in pure stands at age 120 when unfavorable changes in climate conditions were assumed. Increasing species admixture greatly reduced the negative effects of unfavorable climate conditions, resulting in a decline in survival probabilities of only 7%. We conclude that future studies of forest management under climate change as well as forest policy measures need to take this, as yet unconsidered, strongly advantageous effect of tree species mixture into account. © 2014 John Wiley & Sons Ltd.

  11. Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome.

    Science.gov (United States)

    Yuan, Wenping; Liu, Shuguang; Dong, Wenjie; Liang, Shunlin; Zhao, Shuqing; Chen, Jingming; Xu, Wenfang; Li, Xianglan; Barr, Alan; Andrew Black, T; Yan, Wende; Goulden, Mike L; Kulmala, Liisa; Lindroth, Anders; Margolis, Hank A; Matsuura, Yojiro; Moors, Eddy; van der Molen, Michiel; Ohta, Takeshi; Pilegaard, Kim; Varlagin, Andrej; Vesala, Timo

    2014-06-26

    The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting in a substantial overestimation. The magnitude of this overestimation could have important implications regarding a change from a current carbon sink to a carbon source in the boreal region. Moss abundance, associated with ecosystem disturbances, needs to be mapped and incorporated into GPP estimates in order to adequately assess the role of the boreal region in the global carbon cycle.

  12. Comparative Characterization of Multiscale Carbon Fiber Composite with Long and Short MWCNTs at Higher Weight Fractions

    Directory of Open Access Journals (Sweden)

    Michael Zimmer

    2012-01-01

    Full Text Available There are documented advantages to using carbon nanotubes (CNTs in composites for various property enhancements. However, to date, only limited studies have been conducted on using of longer CNTs over 1 mm in length. This study used long multiwalled carbon nanotubes (LMWCNTs and their longer extended networks to test multiple properties in thermal conductivity, electrical conductivity, mechanical strength, and modulus and then compared these properties to those of shorter multi-walled carbon nanotubes (SMWCNTs. For carbon fiber-reinforced composites, the longer graphite paths from LMWCNTs in the matrix were expected to improve all properties. The longer networks were expected to allow for more undisturbed phonon transportation to improve thermal conductivity. This in turn relates to improved electrical conductivity and better mechanical properties. However, results have shown that the LMWCNTs do not improve or decrease thermal conductivity, whereas the shorter MWCNTs provide mixed results. LMWCNTs did show improvements in electrical, mechanical, and physical properties, but compared to shorter MWCNTs, the results in other certain properties varied. This perplexing outcome resides in the functioning of the networks made by both the LMWCNTs and shorter MWCNTs.

  13. Long rotation swidden systems maintain higher carbon stocks than rubber plantations

    DEFF Research Database (Denmark)

    Bruun, Thilde Bech; Berry, Nicholas; De Neergaard, Andreas

    2018-01-01

    Conversion of shifting cultivation to rubber (Hevea brasiliensis) plantations is one of the dominant land use changes in montane mainland areas of Southeast Asia, with the area of rubber expected to quadruple by 2050. However, the impacts of this transition on total ecosystem carbon stocks...... established between 2 and 18 years prior to the study, and fallows used in a swidden system. The carbon stock in the upper 40 cm of the soil was almost 20% lower after 18 years of rubber than in the swidden system fallows, suggesting a SOC loss of 0.74 ± 0.2 Mg C ha−1 yr−1. Rates of biomass accumulation...... in fallows were 1.5 ± 0.12 Mg C ha−1 yr−1 and 1.9 ± 0.14 Mg C ha−1 yr−1 in rubber plantations. When comparing time-averaged carbon stocks of swidden systems to rubber plantations with 30 year rotation periods, the stocks of swidden systems with rotation times of 5 and 10 years were 19% and 13% lower...

  14. Calcium carbonate mediates higher lignin peroxidase activity in the culture supernatant of Streptomyces Viridosporus T7A

    Directory of Open Access Journals (Sweden)

    J. M. B. MACEDO

    1999-06-01

    Full Text Available Lignin peroxidase (LiP production has been extensively studied due to the potential use of this enzyme in environmental pollution control. Important aspects of the production of the enzyme by S. viridosporus T7A which have been studied include the improvement of yield and enzyme stabilization. In experiments performed in agitated flasks containing culture media composed of yeast extract as the source of nitrogen, mineral salts and different carbon sources, the use of glucose resulted in the highest values for LiP activity (350 U/L, specific LiP activity (450 U/g and productivity (7 U/L/h. As the profile obtained with glucose-containing medium suggested enzyme instability, the effect of calcium carbonate was evaluated. The addition of CaCO3 in two different concentrations, 0.5% and 5.0%, resulted in higher values of maximum LiP activity, 600 and 900 U/L, respectively. The presence of this salt also anticipated enzyme activity peaks and allowed the detection of higher enzyme activities in the extracellular medium for longer periods of time. These results indicate a positive effect of calcium carbonate on LiP production, which is extremely relevant for industrial processes.

  15. New science of climate change impacts on agriculture implies higher social cost of carbon.

    Science.gov (United States)

    Moore, Frances C; Baldos, Uris; Hertel, Thomas; Diaz, Delavane

    2017-11-20

    Despite substantial advances in climate change impact research in recent years, the scientific basis for damage functions in economic models used to calculate the social cost of carbon (SCC) is either undocumented, difficult to trace, or based on a small number of dated studies. Here we present new damage functions based on the current scientific literature and introduce these into an integrated assessment model (IAM) in order to estimate a new SCC. We focus on the agricultural sector, use two methods for determining the yield impacts of warming, and the GTAP CGE model to calculate the economic consequences of yield shocks. These new damage functions reveal far more adverse agricultural impacts than currently represented in IAMs. Impacts in the agriculture increase from net benefits of $2.7 ton-1 CO2 to net costs of $8.5 ton-1, leading the total SCC to more than double.

  16. A Cenozoic record of the equatorial Pacific carbonate compensation depth

    Digital Repository Service at National Institute of Oceanography (India)

    Palike, H.; Lyle, M.W.; Nishi, H.; Raffi, I.; Ridgwell, A.; Gamage, K.; Klaus, A.; Acton, G.; Anderson, L.; Backman, J.; Baldauf, J.; Beltran, C.; Bohaty, S.M.; Bown, P.; Busch, W.; Channell, J.E.T.; Chun, C.O.J.; Delaney, M.; Dewangan, P.; et al.

    an important role in climate regulation1. Integrated Ocean Drilling Program (IODP) Expeditions 320/321, the "Pacific Equatorial Age Transect" (PEAT), exploited the northward Pacific plate trajectory during the Cenozoic to recover a continuous sediment... the locus of carbonate deposition between shelf and deep ocean. Therefore, increasing solute supply should be coupled to increased weathering, a warmer climate, and higher CO2, unless changes in orbital configuration significantly enhance or reduce...

  17. Differential dissolution of biogenic carbonates: Implications of secretion at higher pH

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.

    H than rest of the chambers secreted by babies outside the mother test. The chambers formed at higher seawater pH will have more magnesium and thus increased tendency to break/dissolve than the chambers formed at lower pH which will be relatively more...

  18. Enzyme renaturation to higher activity driven by the sol-gel transition: Carbonic anhydrase

    Science.gov (United States)

    Vinogradov, Vladimir V.; Avnir, David

    2015-09-01

    We describe a so-far unknown route for renaturing denatured enzymes, namely subjecting the denatured enzyme to an oxide sol-gel transition. The phenomenon was revealed in a detailed study of denatured carbonic anhydrase which was subjected to an alumina sol-gel transition, up to the thermally stabilizing entrapment in the final xerogel. Remarkably, not only that the killed enzyme regained its activity during the sol-gel process, but its activity increased to 180% of the native enzyme. To the best of our knowledge, this is the first report of enhanced activity following by renaturing (a “Phoenix effect”). Kinetic study which revealed a five-orders of magnitude (!) increase in the Arrhenius prefactor upon entrapment compared to solution. Circular dichroism analysis, differential scanning calorimetry, zeta potential analyses as well as synchronous fluorescence measurements, all of which were used to characterize the phenomenon, are consistent with a proposed mechanism which is based on the specific orienting interactions of the active site of the enzyme with respect to the alumina interface and its pores network.

  19. Synthesis of higher alcohols from carbon monoxide and hydrogen in a slurry reactor

    Energy Technology Data Exchange (ETDEWEB)

    McCutchen, M. Shawn [North Carolina State Univ., Raleigh, NC (United States)

    1992-08-28

    Higher, i.e. C2+, alcohols are desired as gasoline additives, feedstocks for producing ethers and as alternative fuels for automobiles. In all cases, the backbone branching of an alcohol improves octane rating, which is essential for good engine performance. These types of branched, higher alcohols are the desired products for a process converting synthesis gas, a CO and H2 mixture, often generated from coal gasification. Based on this premise, promoted ZnCr oxide catalysts appear to be as one of the best avenues for further investigation. Once this investigation is complete, a natural extension is to replace the Cr in the ZnCr oxide catalyst with Mo and W, both in the same elemental triad with Cr. Mo has already been shown as an active HAS catalyst, both on a SiO2 support and in the MoS2 form. The three catalyst combinations, ZnMo, ZnW, and MnCr oxides will be tested in the stirred autoclave system. However, if none of the three indicate any comparable activity and/or selectivity toward higher alcohols as compared with other HAS catalysts, then an investigation of the effects of Cs promotion on the ZnCr oxide methanol catalysts will be executed.

  20. Mechanisms for Amplified Central European Summer Precipitation Extremes in a Warmer Mediterranean Climate

    Science.gov (United States)

    Volosciuk, Claudia; Maraun, Douglas; Semenov, Vladimir; Tilinina, Natalia; Latif, Mojib

    2015-04-01

    Central European climate is influenced by the Mediterranean Sea, where a strong increase in sea surface temperature (SST) has been observed during the last four decades. One example of extreme weather events are cyclones following the "Vb" pathway. These cyclones are generated over the Mediterranean Sea, travel northeastwards around the Alps and then hit central European countries. These cyclones carry large amounts of moisture and cause extreme precipitation, and subsequently flooding, particularly in summer. To investigate the mechanisms causing increased summer extreme precipitation due to increased Mediterranean SST in Europe, we analyze a series of simulations with the atmospheric general circulation model ECHAM5. In the control run, we forced the model with the 1970-1999 SST climatology. In an additional run, we replaced the Mediterranean and Black Sea SST forcing with the climatology of the warmer 2000-2012 period. ECHAM5 was run at high horizontal resolution (T159) and integrated for 40 years in each experiment. 20-season return levels were derived as a measure of extreme precipitation for daily precipitation in JJA (June - August). These return levels are estimated as quantiles of a stationary generalized Pareto distribution, based on exceedances of the 95th precipitation percentile. We have shown in a previous contribution that precipitation return levels in JJA increase along the Vb cyclone track although the number of Vb cyclones does not increase. Here we discuss the mechanisms responsible for this increase. Due to the warmer climate in the Mediterranean region, climatological mean evaporation and precipitable water in the atmosphere are increased. On extreme days, composites show an even further increase in precipitable water over the central European region. On these extreme days, a higher sea level pressure gradient between central Europe and the Atlantic causes enhanced cyclonic flow that transports more moisture from the Mediterranean region to

  1. Projected carbon dioxide to increase grass pollen and allergen exposure despite higher ozone levels.

    Directory of Open Access Journals (Sweden)

    Jennifer M Albertine

    Full Text Available One expected effect of climate change on human health is increasing allergic and asthmatic symptoms through changes in pollen biology. Allergic diseases have a large impact on human health globally, with 10-30% of the population affected by allergic rhinitis and more than 300 million affected by asthma. Pollen from grass species, which are highly allergenic and occur worldwide, elicits allergic responses in 20% of the general population and 40% of atopic individuals. Here we examine the effects of elevated levels of two greenhouse gases, carbon dioxide (CO2, a growth and reproductive stimulator of plants, and ozone (O3, a repressor, on pollen and allergen production in Timothy grass (Phleum pratense L.. We conducted a fully factorial experiment in which plants were grown at ambient and/or elevated levels of O3 and CO2, to simulate present and projected levels of both gases and their potential interactive effects. We captured and counted pollen from flowers in each treatment and assayed for concentrations of the allergen protein, Phl p 5. We found that elevated levels of CO2 increased the amount of grass pollen produced by ∼50% per flower, regardless of O3 levels. Elevated O3 significantly reduced the Phl p 5 content of the pollen but the net effect of rising pollen numbers with elevated CO2 indicate increased allergen exposure under elevated levels of both greenhouse gases. Using quantitative estimates of increased pollen production and number of flowering plants per treatment, we estimated that airborne grass pollen concentrations will increase in the future up to ∼200%. Due to the widespread existence of grasses and the particular importance of P. pratense in eliciting allergic responses, our findings provide evidence for significant impacts on human health worldwide as a result of future climate change.

  2. Biochemical hydrogen isotope fractionation during biosynthesis in higher plants reflects carbon metabolism of the plant

    Science.gov (United States)

    Cormier, Marc-André; Kahmen, Ansgar

    2015-04-01

    Compound-specific isotope analyses of plant material are frequently applied to understand the response of plants to the environmental changes. As it is generally assume that the main factors controlling δ2H values in plants are the plant's source water and evaporative deuterium enrichment of leaf water, hydrogen isotope analyses of plant material are mainly applied regarding hydrological conditions at different time scales. However, only few studies have directly addressed the variability of the biochemical hydrogen isotope fractionation occurring during biosynthesis of organic compounds (ɛbio), accounting also for a large part in the δ2H values of plants but generally assumed to be constant. Here we present the results from a climate-controlled growth chambers experiment where tested the sensitivity of ɛbio to different light treatments. The different light treatments were applied to induce different metabolic status (autotrophic vs. heterotrophic) in 9 different plant species that we grew from large storage organs (e.g. tubers or roots). The results show a systematic ɛbio shift (up to 80 ) between the different light treatments for different compounds (i.e. long chain n-alkanes and cellulose). We suggest that this shift is due to the different NADPH pools used by the plants to build up the compounds from stored carbohydrates in heterotrophic or autotrophic conditions. Our results have important implications for the calibration and interpretation of sedimentary and tree rings records in geological studies. In addition, as the δ2H values reflect also strongly the carbon metabolism of the plant, our findings support the idea of δ2H values as an interesting proxy for plant physiological studies.

  3. Higher lying resonances in low-energy electron scattering with carbon monoxide

    CERN Document Server

    Dora, Amar; Chakrabarti, Kalyan

    2016-01-01

    R-matrix calculations on electron collisions with CO are reported whose aim is to identify any higher-lying resonances above the well-reported and lowest $^2\\Pi$ resonance at about 1.6~eV. Extensive tests with respect to basis sets, target models and scattering models are performed. The final results are reported for the larger cc-pVTZ basis set using a 50 state close-coupling (CC) calculation. The Breit-Wigner eigenphase sum and the time-delay methods are used to detect and fit any resonances. Both these methods find a very narrow $^2\\Sigma^+$ symmetry Feshbach-type resonance very close to the target excitation threshold of the b $^3\\Sigma^+$ state which lies at 12.9 eV in the calculations. This resonance is seen in the CC calculation using cc-pVTZ basis set while a CC calculation using the cc-pVDZ basis set does not produce this feature. The electronic structure of CO$^-$ is analysed in the asymptotic region, 45 molecular states are found to correlate with states dissociating to an anion and an atom. Electr...

  4. Genetic engineering to alter carbon flux for various higher alcohol productions by Saccharomyces cerevisiae for Chinese Baijiu fermentation.

    Science.gov (United States)

    Li, Wei; Chen, Shi-Jia; Wang, Jian-Hui; Zhang, Cui-Ying; Shi, Yu; Guo, Xue-Wu; Chen, Ye-Fu; Xiao, Dong-Guang

    2018-02-01

    Higher alcohols significantly influence the quality and flavor profiles of Chinese Baijiu. ILV1-encoded threonine deaminase, LEU1-encoded α-isopropylmalate dehydrogenase, and LEU2-encoded β-isopropylmalate dehydrogenase are involved in the production of higher alcohols. In this work, ILV1, LEU1, and LEU2 deletions in α-type haploid, a-type haploid, and diploid Saccharomyces cerevisiae strains and ILV1, LEU1, and LEU2 single-allele deletions in diploid strains were constructed to examine the effects of these alterations on the metabolism of higher alcohols. Results showed that different genetic engineering strategies influence carbon flux and higher alcohol metabolism in different manners. Compared with the parental diploid strain, the ILV1 double-allele-deletion diploid mutant produced lower concentrations of n-propanol, active amyl alcohol, and 2-phenylethanol by 30.33, 35.58, and 11.71%, respectively. Moreover, the production of isobutanol and isoamyl alcohol increased by 326.39 and 57.6%, respectively. The LEU1 double-allele-deletion diploid mutant exhibited 14.09% increased n-propanol, 33.74% decreased isoamyl alcohol, and 13.21% decreased 2-phenylethanol production, which were similar to those of the LEU2 mutant. Furthermore, the LEU1 and LEU2 double-allele-deletion diploid mutants exhibited 41.72 and 52.18% increased isobutanol production, respectively. The effects of ILV1, LEU1, and LEU2 deletions on the production of higher alcohols by α-type and a-type haploid strains were similar to those of double-allele deletion in diploid strains. Moreover, the isobutanol production of the ILV1 single-allele-deletion diploid strain increased by 27.76%. Variations in higher alcohol production by the mutants are due to the carbon flux changes in yeast metabolism. This study could provide a valuable reference for further research on higher alcohol metabolism and future optimization of yeast strains for alcoholic beverages.

  5. Cold Surge Activity Over the Gulf of Mexico in a Warmer Climate

    Directory of Open Access Journals (Sweden)

    Edgar Perez Perez

    2014-08-01

    Full Text Available Cold surges are a dominant feature of midlatitude tropical interaction. During the North Hemisphere (NH winter, midlatitude waves propagating from the Rocky Mountains into the Gulf of Mexico result in cold surges, also known as Nortes or Tehuantepecers, associated with severe weather over the southern part of Mexico. The magnitude of their intense surface winds, precipitation and drops in surface temperature depends on the characteristics of the midlatitude wave propagating into the tropics. The high spatial resolution (20km X 20km version of the TL959L60-AGC Model of the Meteorological Research Institute of Japan is used to examine changes in cold surge activity under the A1B greenhouse gas emission scenario for the 2080 - 2099 period. The model realistically reproduces the spatial and temporal characteristics of cold surges for the 1980 - 1989 control period. The effect of changes in baroclinicity, static stability and mean flow over North America suggest that in a warmer climate, increased cold surge activity over the Gulf of Mexico would occur. However, these systems would have shorter wavelength (higher phase speeds and shorter lifespans that could reduce the total amount of winter precipitation. The increased frequency of cold surges over the Gulf of Mexico would be a consequence of weaker baroclinicity and static stability in the lower troposphere over the cold surge genesis region, along with more dominant westerly winds, resulting from ENSO-like conditions in the atmospheric circulations over North America.

  6. Nitrous oxide emissions are enhanced in a warmer and wetter world

    Science.gov (United States)

    Griffis, Timothy J.; Chen, Zichong; Baker, John M.; Wood, Jeffrey D.; Millet, Dylan B.; Lee, Xuhui; Venterea, Rodney T.; Turner, Peter A.

    2017-11-01

    Nitrous oxide (N2O) has a global warming potential that is 300 times that of carbon dioxide on a 100-y timescale, and is of major importance for stratospheric ozone depletion. The climate sensitivity of N2O emissions is poorly known, which makes it difficult to project how changing fertilizer use and climate will impact radiative forcing and the ozone layer. Analysis of 6 y of hourly N2O mixing ratios from a very tall tower within the US Corn Belt—one of the most intensive agricultural regions of the world—combined with inverse modeling, shows large interannual variability in N2O emissions (316 Gg N2O-Nṡy‑1 to 585 Gg N2O-Nṡy‑1). This implies that the regional emission factor is highly sensitive to climate. In the warmest year and spring (2012) of the observational period, the emission factor was 7.5%, nearly double that of previous reports. Indirect emissions associated with runoff and leaching dominated the interannual variability of total emissions. Under current trends in climate and anthropogenic N use, we project a strong positive feedback to warmer and wetter conditions and unabated growth of regional N2O emissions that will exceed 600 Gg N2O-Nṡy‑1, on average, by 2050. This increasing emission trend in the US Corn Belt may represent a harbinger of intensifying N2O emissions from other agricultural regions. Such feedbacks will pose a major challenge to the Paris Agreement, which requires large N2O emission mitigation efforts to achieve its goals.

  7. Nitrous oxide emissions are enhanced in a warmer and wetter world.

    Science.gov (United States)

    Griffis, Timothy J; Chen, Zichong; Baker, John M; Wood, Jeffrey D; Millet, Dylan B; Lee, Xuhui; Venterea, Rodney T; Turner, Peter A

    2017-11-07

    Nitrous oxide (N2O) has a global warming potential that is 300 times that of carbon dioxide on a 100-y timescale, and is of major importance for stratospheric ozone depletion. The climate sensitivity of N2O emissions is poorly known, which makes it difficult to project how changing fertilizer use and climate will impact radiative forcing and the ozone layer. Analysis of 6 y of hourly N2O mixing ratios from a very tall tower within the US Corn Belt-one of the most intensive agricultural regions of the world-combined with inverse modeling, shows large interannual variability in N2O emissions (316 Gg N2O-N⋅y(-1) to 585 Gg N2O-N⋅y(-1)). This implies that the regional emission factor is highly sensitive to climate. In the warmest year and spring (2012) of the observational period, the emission factor was 7.5%, nearly double that of previous reports. Indirect emissions associated with runoff and leaching dominated the interannual variability of total emissions. Under current trends in climate and anthropogenic N use, we project a strong positive feedback to warmer and wetter conditions and unabated growth of regional N2O emissions that will exceed 600 Gg N2O-N⋅y(-1), on average, by 2050. This increasing emission trend in the US Corn Belt may represent a harbinger of intensifying N2O emissions from other agricultural regions. Such feedbacks will pose a major challenge to the Paris Agreement, which requires large N2O emission mitigation efforts to achieve its goals. Published under the PNAS license.

  8. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

    Directory of Open Access Journals (Sweden)

    Abir U Igamberdiev

    2016-07-01

    Full Text Available Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve, while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve. This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium.

  9. Higher atmospheric levels and contribution of black carbon in soil-air partitioning of organochlorines in Lesser Himalaya.

    Science.gov (United States)

    Ali, Usman; Sweetman, Andrew James; Jones, Kevin C; Malik, Riffat Naseem

    2018-01-01

    Due to influence of wind patterns (monsoon and westerlies) and anthropogenic activities, lower stretch of Himalaya is at direct exposure to persistent organic pollutants (POPs). Current study was designed to monitor atmospheric concentrations of long lived organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) using polyurethane passive air sampling in the Lesser Himalayan Region (LHR) of Pakistan. Levels of ∑HCHs, ∑DDTs and ∑PCBs were observed in a range between 3 and 210 pg m-3, 0.75-67.1 pg m-3 and 8.49-458 pg m-3, respectively. Though, air mass trajectories over LHR indicated long range transport as atmospheric source input which was further explained by Clausius-Clapeyron plots between ln P and inverse of temperature (1000/T; K) where all OCPs and most of the PCBs have shown insignificant relationship (r2 = 5E-06-0.41; p-value = 0.06-0.995). However, local source emissions and valley transport may also implicate based on spatial distribution and altitudinal patterns. Additionally, soil-air partitioning of organochlorines was assessed using octanol-air partition (KOA) and black carbon-air partition (KBC) based models. Regression results indicated combined influence of both organic matter (r2 = 0.298-0.85) and black carbon (r2 = 0.31-0.86) via absorption and adsorption, respectively in soil-air partitioning of OCs in LHR. This paper sheds light on the atmospheric concentrations of OCs and help in better understanding of the processes involved in fate and transport of organic pollutants in Himalayan region. Further investigations are required to understand the role of carbon moieties in fate and transport of other groups of organic pollutants at higher altitudes of Himalayan region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Stronger sexual selection in warmer waters: the case of a sex role reversed pipefish.

    Directory of Open Access Journals (Sweden)

    Nuno M Monteiro

    Full Text Available In order to answer broader questions about sexual selection, one needs to measure selection on a wide array of phenotypic traits, simultaneously through space and time. Nevertheless, studies that simultaneously address temporal and spatial variation in reproduction are scarce. Here, we aimed to investigate the reproductive dynamics of a cold-water pipefish simultaneously through time (encompassing variation within each breeding cycle and as individuals grow and space (by contrasting populations experiencing distinct water temperature regimes in order to test hypothesized differences in sexual selection. Even though the sampled populations inhabited locations with very different water temperature regimes, they exhibited considerable similarities in reproductive parameters. The most striking was the existence of a well-defined substructure in reproductive activity, where larger individuals reproduce for longer periods, which seemed dependent on a high temperature threshold for breeding rather than on the low temperatures that vary heavily according to latitude. Furthermore, the perceived disparities among populations, such as size at first reproduction, female reproductive investment, or degree of sexual size dimorphism, seemed dependent on the interplay between seawater temperature and the operational sex ratio (OSR. Contrary to our expectations of an enhanced opportunity for sexual selection in the north, we found the opposite: higher female reproductive investment coupled with increased sexual size dimorphism in warmer waters, implying that a prolonged breeding season does not necessarily translate into reduced sexual selection pressure. In fact, if the limited sex has the ability to reproduce either continuously or recurrently during the entire breeding season, an increased opportunity for sexual selection might arise from the need to compete for available partners under strongly biased OSRs across protracted breeding seasons. A more general

  11. The Uses of Copper and Zinc Aluminates to Capture and Convert Carbon dioxide to Syn-gas at Higher Temperature

    Directory of Open Access Journals (Sweden)

    R.Y. Raskar

    2014-03-01

    Full Text Available The uses of copper and zinc aluminates to capture and convert the CO2 to syn-gas were studied at higher temperatures. The samples of copper and zinc aluminates were prepared by solid-solid fusion method by calcining in air at 900 oC for 3 h. Those samples were characterized by acidity/alkalinity, surface area, XRD pattern, IR, SEM images and screening to capture CO2 at the different temperatures. The phases Cu2O, CuO, ZnO, CuAl2O4 and ZnAl2O4 were found to be in the samples of zinc and copper aluminates. Acidity and surface area of the samples of copper and zinc aluminates were found to be in the ranges from 0.063 to 9.37 mmol g-1 and 3.04 to 11.8 m2 g-1, respectively. The captured CO2 by the samples of copper and zinc aluminates was found to be 19.92 to 31.52 wt% for the temperature range 40 to 850 oC. The captured CO2 at 550 oC by variable Zn/Al and Cu/Al mol ratio from 0.5 to 6 of the samples of copper and zinc aluminates was found to be 12.81 to 18.04 wt%. The reduction of carbon dioxide by zinc and copper aluminates was observed. The conversion of CO2 by methane over variable mol ratio of Cu/Al and Zn/Al in copper and zinc aluminates, respectively, at 500 oC showed the production of syn-gas by using the gas hourly space velocities (GHSV 12000, 12000 and 6000 ml. h-1. g-1 of helium, CO2 and methane. The conversions of CO2 by methane over the samples of zinc and copper aluminates were studied at different mol ratios of CO2 to methane.  © 2014 BCREC UNDIP. All rights reservedReceived: 13rd May 2013; Revised: 8th November 2013; Accepted: 8th November 2013[How to Cite: Raskar, R.Y., Gaikwad, A.G. (2014. The Uses of Copper and Zinc Aluminates to Cap-ture and Convert Carbon Dioxide to Syn-gas at Higher Temperature. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 1-15. (doi:10.9767/bcrec.9.1.4899.1-15[Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.4899.1-15

  12. Marine ecology. Warmer waters more deadly to coral reefs than pollution.

    Science.gov (United States)

    Normile, D

    2000-10-27

    Contrary to conventional wisdom, warmer ocean waters are a greater threat to coral reefs than local environmental insults. That assessment comes from a new scientific report released this week that documents a sudden and steep jump in damage stemming from the 1997-98 El Niño-La Niña event.

  13. Severe Autumn storms in future Western Europe with a warmer Atlantic Ocean

    NARCIS (Netherlands)

    Baatsen, Michiel; Haarsma, Reindert J.; Van Delden, Aarnout J.; De Vries, Hylke

    2014-01-01

    Simulations with a very high resolution (~25 km) global climate model indicate that more severe Autumn storms will impact Europe in a warmer future climate. The observed increase is mainly attributed to storms with a tropical origin, especially in the later part of the twentyfirst century. As their

  14. Epidemic malaria and warmer temperatures in recent decades in an East African highland

    NARCIS (Netherlands)

    Alonso, David; Bouma, Menno J.; Pascual, Mercedes

    2011-01-01

    Climate change impacts on malaria are typically assessed with scenarios for the long-term future. Here we focus instead on the recent past (1970-2003) to address whether warmer temperatures have already increased the incidence of malaria in a highland region of East Africa. Our analyses rely on a

  15. Warmer spring conditions increase annual methane emissions from a boreal peat landscape with sporadic permafrost

    Science.gov (United States)

    Helbig, Manuel; Quinton, William L.; Sonnentag, Oliver

    2017-11-01

    About a fifth of the global wetland methane emissions originate from boreal peatlands, which represent an important land cover type in boreal landscapes in the sporadic permafrost zone. There, rising air temperatures could lead to warmer spring and longer growing seasons, changing landscape methane emissions. To quantify the effect of warmer spring conditions on methane emissions of a boreal peat landscape in the sporadic permafrost zone of northwestern Canada, we analyzed four years (2013–2016) of methane fluxes measured with the eddy covariance technique and long-term (1951–2016) meteorological observations from a nearby climate station. In May, after snowmelt was complete, mean air temperatures were more than 2 °C warmer in 2013, 2015, and 2016 than in 2014. Mean growing season (May–August) air temperatures, in contrast, differed by less than 1 °C over the four years. Warmer May air temperatures caused earlier wetland soil warming, with temperatures rising from ~0 °C to >12 °C 25 to 40 days earlier and leading to ~6 °C warmer mean soil temperatures between May and June. However, from July to August, soil temperatures were similar among years. Mean May to August and annual methane emissions (6.4 g CH4 m‑2 and 9.4 g CH4 m‑2, respectively) of years with warmer spring (i.e. May) temperatures exceeded emissions during the cooler year by 20%–30% (4.5 g CH4 m‑2 and 7.2 g CH4 m‑2, respectively). Among years with warmer springs, growing season methane emissions varied little (±0.5 g CH4 m‑2). The observed interannual differences are most likely caused by a strong soil temperature control on methane fluxes and large soil temperature differences during the spring. Thus, in a warming climate, methane emissions from waterlogged boreal peat landscapes at the southern limit of permafrost are likely to increase in response to more frequent occurrences of warm springs.

  16. Can latent heat safely warm blood? – in vitro testing of a portable prototype blood warmer

    Directory of Open Access Journals (Sweden)

    McEwen Mark P

    2007-08-01

    Full Text Available Abstract Background Trauma/retrieval patients are often in shock and hypothermic. Treatment of such patients usually involves restoring their blood volume with transfusion of blood (stored at 2°C – 6°C and/or crystalloids or colloids (stored at ambient temperature. Rapid infusion of these cold fluids can worsen or even induce hypothermia in these patients. Warming of intravenous fluids at accident sites has traditionally been difficult due to a lack of suitable portable fluid warmers that are not dependent on mains electrical or battery power. If latent heat, the heat released when a liquid solidifies (an inherently temperature limiting process can warm intravenous fluids, portable devices without a reliance on electrical energy could be used to reduce the incidence of hypothermia in trauma patients. Methods Rapid infusion of red cells into patients was timed to sample typical clinical flow rates. An approved dry heat blood warmer was compared with a prototype blood warmer using a supercooled liquid latent heat storage material, to warm red cells whilst monitoring inlet and outlet temperatures. To determine the effect of warming on red cell integrity compared to the normal storage lesion of blood, extracellular concentrations of potassium, lactate dehydrogenase and haemoglobin were measured in blood which had been warmed after storage at 2°C – 6°C for 1 to 42 days. Results A prototype latent heat fluid warmer consistently warmed red cells from approximately 4°C to approximately 35°C at typical clinical flow rates. Warming of stored blood with latent heat did not affect red cell integrity more than the approved dry heat blood warmer. Conclusion Using latent heat as an energy source can satisfactorily warm cold blood or other intravenous fluids to near body temperature, without any adverse affects.

  17. The role of amoeboid protists and the microbial community in moss-rich terrestrial ecosystems: biogeochemical implications for the carbon budget and carbon cycle, especially at higher latitudes.

    Science.gov (United States)

    Anderson, O Roger

    2008-01-01

    Moss-rich terrestrial communities are widely distributed in low- and high-latitude environments, covering vast surface areas in the boreal forests and tundra. The microbial biota in these organic-rich communities may contribute substantially to the carbon budget of terrestrial communities and the carbon cycle on a global scale. Recent research is reported on the carbon content of microbial communities in some temperate and high-latitude moss communities. The total carbon content and potential respiratory carbon dioxide (CO(2)) efflux is reported for bacteria, microflagellates, naked amoebae, and testate amoebae within sampling sites at a northeastern forest and the tundra at Toolik, Alaska. Quantitative models of the predicted total CO(2) efflux from the microbes, based on microscopic observations and enumeration of the microbiota in samples from the research sites, are described and predictions are compared with published field-based data of CO(2) efflux. The significance of the predictions for climate change and global warming are discussed.

  18. A Neogene Higher Plant N-Alkane Carbon and Hydrogen Isotope Record From the Gulf of Mexico

    Science.gov (United States)

    Tipple, B. J.; Pagani, M.

    2006-12-01

    Water availability and a plant's capacity to cope with water stress are expressed in carbon and hydrogen isotopic compositions of leaf waxes. Therefore, coupled sedimentary n-alkane δ13C and δD isotope records provide unique continental-scale information about the paleo-hydrological cycle and its influence on biology over long time scales. In this study, we assess the relationship between Neogene North American climate and floral change, particularly C4 grass expansion, by establishing δ13C and δD records of higher-plant leaf wax n-alkanes from Gulf of Mexico sediments (DSDP site 94). Changes in the hydrogen isotope composition of leaf water can be driven by changes in evaporation/evapotranspiration or changes in the evaporative source from which precipitation derives. However, for this study changes in moisture source are unlikely because these sediments located in Gulf of Mexico likely received the majority of precipitation from the Gulf of Mexico itself over the time interval studied. In general, δ13C and δD values shift in concert, with the most positive δ13C and δD values occurring near the Epoch boundaries. N-alkane δ13C values reflect factors other than water stress alone, including the isotopic composition of atmospheric CO2, plant community, and atmospheric pCO2. Notably, 13C enrichment occurring near the Oligocene/Miocene boundary potentially reflects the rapid decrease in pCO2 at this time. In addition, between 4.5 and 5.5 Ma, n-alkane δ13C values trend more negative as δD becomes increasingly D-enriched, indicative of increased evaporation. Given that contemporaneous North American terrestrial isotope (Passey et al., 2002) and equatorial Atlantic marine (Wagner, 2002) records show similar trends, it appears that major changes in the hydrological cycle took place at this time.

  19. Quantifying the risks of winter damage on overwintering crops under future climates: Will low-temperature damage be more likely in warmer climates?

    Science.gov (United States)

    Vico, G.; Weih, M.

    2014-12-01

    Autumn-sown crops act as winter cover crop, reducing soil erosion and nutrient leaching, while potentially providing higher yields than spring varieties in many environments. Nevertheless, overwintering crops are exposed for longer periods to the vagaries of weather conditions. Adverse winter conditions, in particular, may negatively affect the final yield, by reducing crop survival or its vigor. The net effect of the projected shifts in climate is unclear. On the one hand, warmer temperatures may reduce the frequency of low temperatures, thereby reducing damage risk. On the other hand, warmer temperatures, by reducing plant acclimation level and the amount and duration of snow cover, may increase the likelihood of damage. Thus, warmer climates may paradoxically result in more extensive low temperature damage and reduced viability for overwintering plants. The net effect of a shift in climate is explored by means of a parsimonious probabilistic model, based on a coupled description of air temperature, snow cover, and crop tolerable temperature. Exploiting an extensive dataset of winter wheat responses to low temperature exposure, the risk of winter damage occurrence is quantified under conditions typical of northern temperate latitudes. The full spectrum of variations expected with climate change is explored, quantifying the joint effects of alterations in temperature averages and their variability as well as shifts in precipitation. The key features affecting winter wheat vulnerability to low temperature damage under future climates are singled out.

  20. Reduced reproductive performance associated with warmer ambient temperatures during incubation in a winter-breeding, food-storing passerine.

    Science.gov (United States)

    Whelan, Shannon; Strickland, Dan; Morand-Ferron, Julie; Norris, D Ryan

    2017-05-01

    Timing of reproduction can influence individual fitness whereby early breeders tend to have higher reproductive success than late breeders. However, the fitness consequences of timing of breeding may also be influenced by environmental conditions after the commencement of breeding. We tested whether ambient temperatures during the incubation and early nestling periods modulated the effect of laying date on brood size and dominant juvenile survival in gray jays (Perisoreus canadensis), a sedentary boreal species whose late winter nesting depends, in part, on caches of perishable food. Previous evidence has suggested that warmer temperatures degrade the quality of these food hoards, and we asked whether warmer ambient temperatures during the incubation and early nestling periods would be associated with smaller brood sizes and lower summer survival of dominant juveniles. We used 38 years of data from a range-edge population of gray jays in Algonquin Provincial Park, Ontario, where the population has declined over 50% since the study began. Consistent with the "hoard-rot" hypothesis, we found that cold temperatures during incubation were associated with larger brood sizes in later breeding attempts, but temperatures had little effect on brood size for females breeding early in the season. This is the first evidence that laying date and temperature during incubation interactively influence brood size in any bird species. We did not find evidence that ambient temperatures during the incubation period or early part of the nestling period influenced summer survival of dominant juveniles. Our findings provide evidence that warming temperatures are associated with some aspects of reduced reproductive performance in a species that is reliant on cold temperatures to store perishable food caches, some of which are later consumed during the reproductive period.

  1. On an Exact Mapping and a Higher Order Born Rule for Use in Analyzing Graphene Carbon Nanotubes

    National Research Council Canada - National Science Library

    Leamy, Michael

    2003-01-01

    As part of an effort to model single-walled graphene carbon nanotubes, a transformation is first described which maps atom locations originally on a planar sheet to atom locations on a cylindrical nanotube...

  2. Carbonic anhydrase IX is a marker of hypoxia and correlates with higher Gleason scores and ISUP grading in prostate cancer.

    Science.gov (United States)

    Ambrosio, Maria Raffaella; Di Serio, Claudia; Danza, Giovanna; Rocca, Bruno Jim; Ginori, Alessandro; Prudovsky, Igor; Marchionni, Niccolò; Del Vecchio, Maria Teresa; Tarantini, Francesca

    2016-05-25

    Carbonic anhydrase IX is a member of α-carbonic anhydrases that is preferentially expressed in solid tumors. It enables bicarbonate transport across the plasma membrane, neutralizing intracellular pH and conferring to cancer cells a survival advantage in hypoxic/acidic microenvironments. Overexpression of carbonic anhydrase IX in cancer tissues is regulated by hypoxia inducible factor 1α - mediated transcription and the enzyme is considered a marker of tumor hypoxia and poor outcome. The role of carbonic anhydrase IX in prostate cancer has not been fully clarified and controversy has arisen on whether this enzyme is overexpressed in hypoxic prostate cancer tissues. We analyzed the expression of carbonic anhydrase IX and hypoxia inducible factor 1α in two prostate cancer cell lines, LNCaP and PC-3, and in 110 cancer biopsies, by western blotting and immunocyto/histochemistry. In LNCaP and PC-3 cells, carbonic anhydrase IX was mostly cytoplasmic/nuclear, with very limited membrane localization. Nuclear staining became stronger under hypoxia. When we analyzed carbonic anhydrase IX expression in human prostate cancer biopsies, we found that protein staining positively correlated with hypoxia inducible factor 1α and with Gleason pattern and score, as well as with the novel grading system proposed by the International Society of Urological Pathology for prostate cancer. Once more, carbonic anhydrase IX was mainly cytoplasmic in low grade carcinomas, whereas in high grade tumors was strongly expressed in the nucleus of the neoplastic cell. An association between carbonic anhydrase IX expression level and the main clinic-pathological features involved in prostate cancer aggressiveness was identified. There was a statistically significant association between carbonic anhydrase IX and hypoxia inducible factor 1α in prostate cancer tissues, that identifies the enzyme as a reliable marker of tumor hypoxia. In addition, carbonic anhydrase IX expression positively

  3. Warm spring reduced carbon cycle impact of the 2012 US summer drought.

    Science.gov (United States)

    Wolf, Sebastian; Keenan, Trevor F; Fisher, Joshua B; Baldocchi, Dennis D; Desai, Ankur R; Richardson, Andrew D; Scott, Russell L; Law, Beverly E; Litvak, Marcy E; Brunsell, Nathaniel A; Peters, Wouter; van der Laan-Luijkx, Ingrid T

    2016-05-24

    The global terrestrial carbon sink offsets one-third of the world's fossil fuel emissions, but the strength of this sink is highly sensitive to large-scale extreme events. In 2012, the contiguous United States experienced exceptionally warm temperatures and the most severe drought since the Dust Bowl era of the 1930s, resulting in substantial economic damage. It is crucial to understand the dynamics of such events because warmer temperatures and a higher prevalence of drought are projected in a changing climate. Here, we combine an extensive network of direct ecosystem flux measurements with satellite remote sensing and atmospheric inverse modeling to quantify the impact of the warmer spring and summer drought on biosphere-atmosphere carbon and water exchange in 2012. We consistently find that earlier vegetation activity increased spring carbon uptake and compensated for the reduced uptake during the summer drought, which mitigated the impact on net annual carbon uptake. The early phenological development in the Eastern Temperate Forests played a major role for the continental-scale carbon balance in 2012. The warm spring also depleted soil water resources earlier, and thus exacerbated water limitations during summer. Our results show that the detrimental effects of severe summer drought on ecosystem carbon storage can be mitigated by warming-induced increases in spring carbon uptake. However, the results also suggest that the positive carbon cycle effect of warm spring enhances water limitations and can increase summer heating through biosphere-atmosphere feedbacks.

  4. Decreasing resilience of kelp beds along a latitudinal temperature gradient: potential implications for a warmer future.

    Science.gov (United States)

    Wernberg, Thomas; Thomsen, Mads S; Tuya, Fernando; Kendrick, Gary A; Staehr, Peter A; Toohey, Benjamin D

    2010-06-01

    Successful mitigation of negative effects of global warming will depend on understanding the link between physiological and ecological responses of key species. We show that while metabolic adjustment may assist Australasian kelp beds to persist and maintain abundance in warmer waters, it also reduces the physiological responsiveness of kelps to perturbation, and suppresses canopy recovery from disturbances by reducing the ecological performance of kelp recruits. This provides a warning not to rely solely on inventories of distribution and abundance to evaluate ecosystem function. The erosion of resilience is mediated by a shift in adult-juvenile interactions from competitive under cool to facilitative under warm conditions, supporting the prediction that positive interactions may become increasingly important in a warmer future. Kelp beds may remain intact but with a lower threshold for where additional impacts (e.g., extreme storms or reduced water quality) will lead to persistent loss of habitat and ecological function.

  5. Effects of a warmer climate on seed germination in the subarctic

    Science.gov (United States)

    Milbau, Ann; Graae, Bente Jessen; Shevtsova, Anna; Nijs, Ivan

    2009-01-01

    Background and Aims In a future warmer subarctic climate, the soil temperatures experienced by dispersed seeds are likely to increase during summer but may decrease during winter due to expected changes in snow depth, duration and quality. Because little is known about the dormancy-breaking and germination requirements of subarctic species, how warming may influence the timing and level of germination in these species was examined. Methods Under controlled conditions, how colder winter and warmer summer soil temperatures influenced germination was tested in 23 subarctic species. The cold stratification and warm incubation temperatures were derived from real soil temperature measurements in subarctic tundra and the temperatures were gradually changed over time to simulate different months of the year. Key Results Moderate summer warming (+2·5 °C) substantially accelerated germination in all but four species but did not affect germination percentages. Optimum germination temperatures (20/10°C) further decreased germination time and increased germination percentages in three species. Colder winter soil temperatures delayed the germination in ten species and decreased the germination percentage in four species, whereas the opposite was found in Silene acaulis. In most species, the combined effect of a reduced snow cover and summer warming resulted in earlier germination and thus a longer first growing season, which improves the chance of seedling survival. In particular the recruitment of (dwarf) shrubs (Vaccinium myrtillus, V. vitis-idaea, Betula nana), trees (Alnus incana, Betula pubescens) and grasses (Calamagrostis lapponica, C. purpurea) is likely to benefit from a warmer subarctic climate. Conclusions Seedling establishment is expected to improve in a future warmer subarctic climate, mainly by considerably earlier germination. The magnitudes of the responses are species-specific, which should be taken into account when modelling population growth and migration

  6. Photosynthetic oxygen production in a warmer ocean: the Sargasso Sea as a case study

    Science.gov (United States)

    Richardson, Katherine; Bendtsen, Jørgen

    2017-08-01

    Photosynthetic O2 production can be an important source of oxygen in sub-surface ocean waters especially in permanently stratified oligotrophic regions of the ocean where O2 produced in deep chlorophyll maxima (DCM) is not likely to be outgassed. Today, permanently stratified regions extend across approximately 40% of the global ocean and their extent is expected to increase in a warmer ocean. Thus, predicting future ocean oxygen conditions requires a better understanding of the potential response of photosynthetic oxygen production to a warmer ocean. Based on our own and published observations of water column processes in oligotrophic regions, we develop a one-dimensional water column model describing photosynthetic oxygen production in the Sargasso Sea to quantify the importance of photosynthesis for the downward flux of O2 and examine how it may be influenced in a warmer ocean. Photosynthesis is driven in the model by vertical mixing of nutrients (including eddy-induced mixing) and diazotrophy and is found to substantially increase the downward O2 flux relative to physical-chemical processes alone. Warming (2°C) surface waters does not significantly change oxygen production at the DCM. Nor does a 15% increase in re-mineralization rate (assuming Q10 = 2; 2°C warming) have significant effect on net sub-surface oxygen accumulation. However, changes in the relative production of particulate (POM) and dissolved organic material (DOM) generate relatively large changes in net sub-surface oxygen production. As POM/DOM production is a function of plankton community composition, this implies plankton biodiversity and food web structure may be important factors influencing O2 production in a warmer ocean. This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.

  7. Recent bottom sediments from Chukchi Sea, sampled northeast of Wrangel Island, indicate warmer climate (preliminary results)

    Science.gov (United States)

    Vologina, Elena G.; Sturm, Michael; Kolesnik, Alexandr N.; Bosin, Alexandr A.

    2014-05-01

    A short sediment core (37 cm long) was collected in Chukchi Sea at water depth 100 m northeast of Wrangel Island within the framework of the Russian-American project RUSALCA. Coordinates of coring site: 72º32.54'N 175º58.70'W. The sediments consist of silty clay and clayey silt with small admixtures of sand. They contain diatoms and spiculae of sponges. The deposits are olive-gray to greenish-gray and show black spots and stripes of hydrotroilite. Magnetic susceptibility varies from 28-42•10-6 SI units, with minimum values (28-32•10-6 SI units) observed in the uppermost 0-2 cm of the core. The generally constant magnetic susceptibility and the homogeneous lithology indicate calm conditions during sedimentation. Recent sedimentation rates, measured by 210Pb, average 0.7 mm/year. Thus the age of the studied sediment column is up to 530 years old, which corresponds to the Late Holocene [1]. Contents of biogenic silica (Sibio), mainly from diatoms, change from 11.14-16.00 %. Maximum values are observed in the uppermost part of the core at 0-1 cm (14.44 %) and down-core at 35 cm (16.00 %). Minimum contents correspond to core depths of 4-7 cm, 32 cm and 36 cm. Concentration of organic carbon (Corg) and total nitrogen (Ntot) are generally well correlated with biogenic silica. Maximum contents are observed in the interval 0-1 cm (2.19 % Corg and 0.28 % Ntot), minimum concentrations at intervals 5-6 cm (1.63-1.67 % Corg, 0.20-0.21 % Ntot.) and 31-33 cm (1.35-1.60 % Corg, 0.17-0.20 % Ntot). Concentrations of Corg and Ntot are mainly constant between 7 and 30 cm. In general, contents of Ntot are very small in the sediments. C/N ratios vary between 9-10, indicating a predominance of autochthonous organic matter in the deposits. The interval 0-1 cm corresponds to about the last 14 years. The high nutrient concentrations within this interval are caused probably by the increase of biological productivity in the Chukchi Sea increased during this time. This could be caused by

  8. MWCNT Coated Free-Standing Carbon Fiber Fabric for Enhanced Performance in EMI Shielding with a Higher Absolute EMI SE

    Directory of Open Access Journals (Sweden)

    Sudesh Jayashantha Pothupitiya Gamage

    2017-11-01

    Full Text Available A series of multi-walled carbon nanotube (MWCNT coated carbon fabrics was fabricated using a facile dip coating process, and their performance in electrical conductivity, thermal stability, tensile strength, electromagnetic interference (EMI and shielding effectiveness (SE was investigated. A solution of MWCNT oxide and sodium dodecyl sulfate (SDS in water was used in the coating process. MWCNTs were observed to coat the surfaces of carbon fibers and to fill the pores in the carbon fabric. Electrical conductivity of the composites was 16.42 S cm−1. An EMI shielding effectiveness of 37 dB at 2 GHz was achieved with a single layer of C/C composites, whereas the double layers resulted in 68 dB EMI SE at 2.7 GHz. Fabricated composites had a specific SE of 486.54 dB cm3 g−1 and an absolute SE of approximately 35,000 dB cm2 g−1. According to the above results, MWCNT coated C/C composites have the potential to be used in advanced shielding applications such as aerospace and auto mobile electronic devices.

  9. The Value of Energy Efficiency Programs for U.S. Residential and Commercial Buildings in a Warmer World

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Michael J; Dirks, James A; Cort, Katherine A

    2007-06-15

    U.S. residential and commercial buildings currently use about 39 quadrillion Btu (quads) of energy per year and account for 0.6 gigatonnes (GT) of carbon emitted to the atmosphere (38% of U.S. total emissions of 1.6 GT and approximately 9% of the world fossil-fuel related anthropogenic emissions of 6.7 GT). U.S. government buildings-related energy efficiency research and implementation programs are expected to reduce energy consumption in buildings. This has value both in reducing carbon emissions that result in global warming and adapting the U.S. residential and commercial building stock to a potentially warmer world. Analyses conducted by the Intergovernmental Panel on Climate Change (IPCC) show that the world’s climate could warm relative to 1990 by 0.4ºC to 1.2°C by the year 2030 and by 1.4°C to 5.8°C by the end of the 21st century. This paper shows that the effect of the regional projected warming on energy consumption in U.S. residential and commercial buildings is a net decrease ranging from about 5% in 2020 to as much as 20% in 2080, but with an increase of as much as 25% in space cooling. Buildings-related energy efficiency programs should reduce energy consumption in buildings by more than 2 quads in 2020, which would more than offset the growth in space cooling due to climate and growth in building stock combined, and would be worth between $28 and $33 billion.

  10. WARMER URBAN CLIMATES FOR DEVELOPMENT OF GREEN SPACES IN NORTHERN SIBERIAN CITIES

    Directory of Open Access Journals (Sweden)

    Igor Esau

    2016-01-01

    Full Text Available Modern human societies have accumulated considerable power to modify their environment and the earth’s system climate as the whole. The most significant environmental changes are found in the urbanized areas. This study considers coherent changes in vegetation productivity and land surface temperature (LST around four northern West Siberian cities, namely, Tazovsky, Nadym, Noyabrsk and Megion. These cities are located in tundra, forest-tundra, northern taiga and middle taiga bioclimatic zones correspondingly. Our analysis of 15 years (2000–2014 Moderate Resolution Imaging Spectroradiometer (MODIS data revealed significantly (1.3 °C to 5.2 °C warmer seasonally averaged LST within the urbanized territories than those of the surrounding landscapes. The magnitude of the urban LST anomaly corresponds to climates found 300–600 km to the South. In the climate change perspective, this magnitude corresponds to the expected regional warming by the middle or the end of the 21st century. Warmer urban climates, and specifically warmer upper soil layers, can support re-vegetation of the disturbed urban landscapes with more productive trees and tall shrubs. This afforestation is welcome by the migrant city population as it is more consistent with their traditional ecological knowledge. Survival of atypical, southern plant species encourages a number of initiatives and investment to introduce even broader spectrum of temperate blossoming trees and shrubs in urban landscapes. The unintended changes of the urban micro-climates in combination with knowledgeable urban planning could transform the Siberian pioneer settlements into places of belonging.

  11. Icebreakers, Fillers y Warmers: actividades breves para la clase de inglés

    Directory of Open Access Journals (Sweden)

    Ramiro DURÁN MARTÍNEZ

    2009-11-01

    Full Text Available RESUMEN: En el siguiente artículo vamos a presentar diversos tipos de ejercicios de carácter breve que hemos utilizado en la clase de inglés con el objetivo de facilitar a los alumnos la práctica de la destreza oral. Estas actividades tienen distintos nombres dependiendo de la función que desempeñen: icebreakers, fillers y warmers. Se denominan icebreakers los ejercicios diseñados para romper la tensión que normalmente rodea las primeras sesiones de cualquier nueva actividad, como, por ejemplo, la primera clase de un curso de inglés. Cuando se habla de fillers se enfatiza su función comodín: tareas independientes que normalmente sirven para completar los últimos minutos del horario establecido para la clase de idiomas. El término warmer se aplica a las actividades que se llevan a cabo después de un período vacacional con el propósito de favorecer el reencuentro del alumno con el idioma que está estudiando. El principal objetivo de estos ejercicios es el desarrollo de la capacidad de los alumnos para expresarse de forma oral utilizando la lengua inglesa, concentrándose más en la práctica de la fluidez (fluency que en la precisión (accuracy. Por otra parte, sirven para favorecer la creación de vínculos de unión entre un grupo de estudiantes.ABSTRACT: In this paper, we are going to present a number of short activities that have been used in the English class in order to give students extra speaking practice. These activities were given different names depending on the role they play in the class: icebreakers, fillers and warmers. Icebreakers are fluency practice exercises produced to defuse the tension that the first sessions of every new activity imply: i.e. the first lesson of English. When talking about fillers, we refer to short independent activities that are used when the projected exercises have taken less time than expected. Warmers are also fluency practice activities devised to put students back in touch with the

  12. A Convenient Route to Higher Sugars by Two-Carbon Chain Elongation Using Wittig/Dihydroxylation Reactions

    DEFF Research Database (Denmark)

    Jørgensen, Morten; Iversen, Erik Høgh; Madsen, Robert

    2001-01-01

    ,3-threo configuration. When starting from sugars with the 2,3-erythro configuration, the diastereoselectivity in the dihydroxylation is low (2:1-2.5:1). As a result, the Wittig/dihydroxylation protocol is most effective for producing higher sugars with the galacto configuration at the reducing end......The combination of a Wittig olefination and a dihydroxylation reaction constitutes a facile synthetic protocol for the transformation of unprotected carbohydrates into higher sugars. The Wittig reaction is carried out with tert-butyl or diphenylmethyl ester stabilized phosphoranes to give (E......)-configured alpha,beta -unsaturated esters as the only products in most cases. These are dihydroxylated in a diastereoselective fashion using OsO4/NMO. The stereochemical outcome in the dihydroxylation follows Kishi's empirical rule and gives high diastereoselectivity (5:1-8:1) when starting from sugars with the 2...

  13. Wildlife as reservoirs for vector borne diseases in a warmer Scandinavian climate

    DEFF Research Database (Denmark)

    Bødker, Rene; Kristensen, Birgit

    can be attributed global warming. Some of these new infections have important reservoirs in wild animals and this may affect prevention and control of outbreaks in humans and domestic animals. This may also put wild animals at risk of not just infections but also of control efforts targeted......The distribution of vector borne diseases is highly determined by environmental and climatic parameters. As the climate becomes warmer the potential for spread of exotic vector borne diseases may therefore increase in the Nordic countries. But this does not mean that all new outbreaks of diseases...... at eliminating reservoirs. Insect borne Blue tongue, Black tongue, West Nile Virus, Usutu, avian malaria, Dirofilarial worms and Tick Borne Encephalitis are spreading and pose an increasing threat to people and animals in Northern Europe. Climate driven mathematical models may provide quantitative estimates...

  14. What Would Happen to Superstorm Sandy Under the Influence of a Substantially Warmer Atlantic Ocean?

    Science.gov (United States)

    Lau, William K. M.; Shi, J. J.; Tao, W. K.; Kim, K. M.

    2016-01-01

    Based on ensemble numerical simulations, we find that possible responses of Sandy-like superstorms under the influence of a substantially warmer Atlantic Ocean bifurcate into two groups. In the first group, storms are similar to present-day Sandy from genesis to extratropical transition, except they are much stronger, with peak Power Destructive Index (PDI) increased by 50-80%, heavy rain by 30-50%, and maximum storm size (MSS) approximately doubled. In the second group, storms amplify substantially over the interior of the Atlantic warm pool, with peak PDI increased by 100-160%, heavy rain by 70-180%, and MSS more than tripled compared to present-day Superstorm Sandy. These storms when exiting the warm pool, recurve northeastward out to sea, subsequently interact with the developing midlatitude storm by mutual counterclockwise rotation around each other and eventually amplify into a severe Northeastern coastal storm, making landfall over the extreme northeastern regions from Maine to Nova Scotia.

  15. Drivers of Daily Routines in an Ectothermic Marine Predator: Hunt Warm, Rest Warmer?

    Directory of Open Access Journals (Sweden)

    Yannis P Papastamatiou

    Full Text Available Animal daily routines represent a compromise between maximizing foraging success and optimizing physiological performance, while minimizing the risk of predation. For ectothermic predators, ambient temperature may also influence daily routines through its effects on physiological performance. Temperatures can fluctuate significantly over the diel cycle and ectotherms may synchronize behaviour to match thermal regimes in order to optimize fitness. We used bio-logging to quantify activity and body temperature of blacktip reef sharks (Carcharhinus melanopterus at a tropical atoll. Behavioural observations were used to concurrently measure bite rates in herbivorous reef fishes, as an index of activity for potential diurnal prey. Sharks showed early evening peaks in activity, particularly during ebbing high tides, while body temperatures peaked several hours prior to the period of maximal activity. Herbivores also displayed peaks in activity several hours earlier than the peaks in shark activity. Sharks appeared to be least active while their body temperatures were highest and most active while temperatures were cooling, although we hypothesize that due to thermal inertia they were still warmer than their smaller prey during this period. Sharks may be most active during early evening periods as they have a sensory advantage under low light conditions and/or a thermal advantage over cooler prey. Sharks swam into shallow water during daytime low tide periods potentially to warm up and increase rates of digestion before the nocturnal activity period, which may be a strategy to maximize ingestion rates. "Hunt warm, rest warmer" may help explain the early evening activity seen in other ectothermic predators.

  16. Imbalanced nutrient recycling in a warmer ocean driven by differential response of extracellular enzymatic activities

    KAUST Repository

    Ayo, Begoña

    2017-06-08

    Ocean oligotrophication concurrent with warming weakens the capacity of marine primary producers to support marine food webs and act as a CO2 sink, and is believed to result from reduced nutrient inputs associated to the stabilization of the thermocline. However, nutrient supply in the oligotrophic ocean is largely dependent on the recycling of organic matter. This involves hydrolytic processes catalyzed by extracellular enzymes released by bacteria, which temperature-dependence has not yet been evaluated. Here we report a global assessment of the temperature-sensitivity, as represented by the activation energies (Ea ), of extracellular β-glucosidase (βG), leucine aminopeptidase (LAP) and alkaline phosphatase (AP) enzymatic activities, which enable the uptake by bacteria of substrates rich in carbon, nitrogen and phosphorus, respectively. These Ea were calculated from two different approaches, temperature experimental manipulations and a space-for-time substitution approach, which generated congruent results. The three activities showed contrasting Ea in the subtropical and tropical ocean, with βG increasing the fastest with warming, followed by LAP, while AP showed the smallest increase. The estimated activation energies predict that the hydrolysis products under projected warming scenarios will have higher C:N, C:P and N:P molar ratios than those currently generated, and suggest that the warming of oceanic surface waters leads to a decline in the nutrient supply to the microbial heterotrophic community relative to that of carbon, particularly so for phosphorus, slowing down nutrient recycling and contributing to further ocean oligotrophication. This article is protected by copyright. All rights reserved.

  17. Imbalanced nutrient recycling in a warmer ocean driven by differential response of extracellular enzymatic activities.

    Science.gov (United States)

    Ayo, Begoña; Abad, Naiara; Artolozaga, Itxaso; Azua, Iñigo; Baña, Zuriñe; Unanue, Marian; Gasol, Josep M; Duarte, Carlos M; Iriberri, Juan

    2017-10-01

    Ocean oligotrophication concurrent with warming weakens the capacity of marine primary producers to support marine food webs and act as a CO2 sink, and is believed to result from reduced nutrient inputs associated to the stabilization of the thermocline. However, nutrient supply in the oligotrophic ocean is largely dependent on the recycling of organic matter. This involves hydrolytic processes catalyzed by extracellular enzymes released by bacteria, which temperature dependence has not yet been evaluated. Here, we report a global assessment of the temperature-sensitivity, as represented by the activation energies (Ea ), of extracellular β-glucosidase (βG), leucine aminopeptidase (LAP) and alkaline phosphatase (AP) enzymatic activities, which enable the uptake by bacteria of substrates rich in carbon, nitrogen, and phosphorus, respectively. These Ea were calculated from two different approaches, temperature experimental manipulations and a space-for-time substitution approach, which generated congruent results. The three activities showed contrasting Ea in the subtropical and tropical ocean, with βG increasing the fastest with warming, followed by LAP, while AP showed the smallest increase. The estimated activation energies predict that the hydrolysis products under projected warming scenarios will have higher C:N, C:P and N:P molar ratios than those currently generated, and suggest that the warming of oceanic surface waters leads to a decline in the nutrient supply to the microbial heterotrophic community relative to that of carbon, particularly so for phosphorus, slowing down nutrient recycling and contributing to further ocean oligotrophication. © 2017 John Wiley & Sons Ltd.

  18. Atmospheric carbon burial in modern lake basins and its significance for the global carbon budget

    Science.gov (United States)

    Einsele, Gerhard; Yan, Jianping; Hinderer, Matthias

    2001-10-01

    Lake basins (˜2.7×10 6 km 2, about 0.8% of the ocean surface or 2% of the land surface) bury a surprisingly high amount of atmospheric carbon (˜70×10 6 t/a) which reaches more than one fourth of the annual atmospheric carbon burial in the modern oceans. This is mainly accomplished by the rapid accumulation of lacustrine sediments and a very high preservation factor (on average 50 times higher than that in the oceans). Lakes with relatively large drainage areas commonly display the highest carbon accumulation rates. In most cases, burial of organic matter is more important than that of carbonate carbon produced by silicate weathering, in contrast to the oceans where the burial of atmospheric carbonate carbon almost reaches the same amount as that of organic carbon. Exceptions to this rule are closed lake basins in arid to semiarid climate which precipitate a major part of their atmosphere-derived dissolved inorganic carbon (DIC) as carbonate. These results are demonstrated in some detail for L. Qinghai, China, (low contribution of atmospheric carbonate carbon) and L. Turkana, East Africa, (high contribution from silicate rocks). Further data are gained by estimates for a number of closed and open lakes. The drainage areas of the lakes withdraw atmospheric carbon at rates of mostly 1-4 g/m 2/a, calculated from the lacustrine carbon burial. Carbon burial rates in lakes commonly increase with change to wetter and warmer climate (partially larger lake surfaces, higher rates of seasonal carbonate precipitation, trend to stratified lake waters with oxygen-deficient bottom water). Anthropogenic influence mostly enhances the production and preservation of organic carbon in lake basins (often by a factor of 3-4). After the last glacial maximum, the joint action of the globally spreading vegetation, peat growth, and carbon burial in lakes would have been able to reduce the atmospheric carbon pool to one third to one half of its present amount within a time period of 1 ka

  19. Higher temperature sensitivity for stable than for labile soil organic carbon - Evidence from incubations of long-term bare fallow soils

    DEFF Research Database (Denmark)

    Lefèvre, Romain; Barré, Pierre; Moyano, Fernando E.

    2014-01-01

    The impact of climate change on the stability of soil organic carbon (SOC)remains a major source of uncertainty in predicting future changes in atmospheric CO2 levels. One unsettled issue is whether the mineralization response to temperature depends on SOC mineralization rate. Long-term (>25 years......) bare fallow experiments (LTBF) in which the soil is kept free of any vegetation and organic inputs, and their associated archives of soil samples represent a unique research platform to examine this issue as with increasing duration of fallow, the lability of remaining total SOC decreases. We retrieved....... The apparent activation energy (Ea) of SOC was then calculated for similar loss of CO2 at the different temperatures. The Ea was always higher for samples taken at the end of the bare-fallow period, implying a higher temperature sensitivity of stable C than of labile C. Our results provide strong evidence...

  20. Carbon Dioxide Hydrogenation into Higher Hydrocarbons and Oxygenates: Thermodynamic and Kinetic Bounds and Progress with Heterogeneous and Homogeneous Catalysis.

    Science.gov (United States)

    Prieto, Gonzalo

    2017-03-22

    Under specific scenarios, the catalytic hydrogenation of CO 2 with renewable hydrogen is considered a suitable route for the chemical recycling of this environmentally harmful and chemically refractory molecule into added-value energy carriers and chemicals. The hydrogenation of CO 2 into C 1 products, such as methane and methanol, can be achieved with high selectivities towards the corresponding hydrogenation product. More challenging, however, is the selective production of high (C 2+ ) hydrocarbons and oxygenates. These products are desired as energy vectors, owing to their higher volumetric energy density and compatibility with the current fuel infrastructure than C 1 compounds, and as entry platform chemicals for existing value chains. The major challenge is the optimal integration of catalytic functionalities for both reductive and chain-growth steps. This Minireview summarizes the progress achieved towards the hydrogenation of CO 2 to C 2+ hydrocarbons and oxygenates, covering both solid and molecular catalysts and processes in the gas and liquid phases. Mechanistic aspects are discussed with emphasis on intrinsic kinetic limitations, in some cases inevitably linked to thermodynamic bounds through the concomitant reverse water-gas-shift reaction, which should be considered in the development of advanced catalysts and processes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Climate-related changes in peatland carbon accumulation during the last millennium

    Directory of Open Access Journals (Sweden)

    D. J. Charman

    2013-02-01

    Full Text Available Peatlands are a major terrestrial carbon store and a persistent natural carbon sink during the Holocene, but there is considerable uncertainty over the fate of peatland carbon in a changing climate. It is generally assumed that higher temperatures will increase peat decay, causing a positive feedback to climate warming and contributing to the global positive carbon cycle feedback. Here we use a new extensive database of peat profiles across northern high latitudes to examine spatial and temporal patterns of carbon accumulation over the past millennium. Opposite to expectations, our results indicate a small negative carbon cycle feedback from past changes in the long-term accumulation rates of northern peatlands. Total carbon accumulated over the last 1000 yr is linearly related to contemporary growing season length and photosynthetically active radiation, suggesting that variability in net primary productivity is more important than decomposition in determining long-term carbon accumulation. Furthermore, northern peatland carbon sequestration rate declined over the climate transition from the Medieval Climate Anomaly (MCA to the Little Ice Age (LIA, probably because of lower LIA temperatures combined with increased cloudiness suppressing net primary productivity. Other factors including changing moisture status, peatland distribution, fire, nitrogen deposition, permafrost thaw and methane emissions will also influence future peatland carbon cycle feedbacks, but our data suggest that the carbon sequestration rate could increase over many areas of northern peatlands in a warmer future.

  2. Will a warmer and wetter future cause extinction of native Hawaiian forest birds?

    Science.gov (United States)

    Liao, Wei; Timm, Oliver Elison; Zhang, Chunxi; Atkinson, Carter T.; LaPointe, Dennis; Samuel, Michael D.

    2015-01-01

    Isolation of the Hawaiian archipelago produced a highly endemic and unique avifauna. Avian malaria (Plasmodium relictum), an introduced mosquito-borne pathogen, is a primary cause of extinctions and declines of these endemic honeycreepers. Our research assesses how global climate change will affect future malaria risk and native bird populations. We used an epidemiological model to evaluate future bird-mosquito-malaria dynamics in response to alternative climate projections from the Coupled Model Intercomparison Project (CMIP). Climate changes during the second half of the century accelerate malaria transmission and cause a dramatic decline in bird abundance. Different temperature and precipitation patterns produce divergent trajectories where native birds persist with low malaria infection under a warmer and dryer projection (RCP4.5), but suffer high malaria infection and severe reductions under hot and dry (RCP8.5) or warm and wet (A1B) futures. We conclude that future global climate change will cause significant decreases in the abundance and diversity of remaining Hawaiian bird communities. Because these effects appear unlikely before mid-century, natural resource managers have time to implement conservation strategies to protect this unique avifauna from further decimation. Similar climatic drivers for avian and human malaria suggest that mitigation strategies for Hawai'i have broad application to human health.

  3. Women are Warmer but No Less Assertive than Men: Gender and Language on Facebook.

    Science.gov (United States)

    Park, Gregory; Yaden, David Bryce; Schwartz, H Andrew; Kern, Margaret L; Eichstaedt, Johannes C; Kosinski, Michael; Stillwell, David; Ungar, Lyle H; Seligman, Martin E P

    2016-01-01

    Using a large social media dataset and open-vocabulary methods from computational linguistics, we explored differences in language use across gender, affiliation, and assertiveness. In Study 1, we analyzed topics (groups of semantically similar words) across 10 million messages from over 52,000 Facebook users. Most language differed little across gender. However, topics most associated with self-identified female participants included friends, family, and social life, whereas topics most associated with self-identified male participants included swearing, anger, discussion of objects instead of people, and the use of argumentative language. In Study 2, we plotted male- and female-linked language topics along two interpersonal dimensions prevalent in gender research: affiliation and assertiveness. In a sample of over 15,000 Facebook users, we found substantial gender differences in the use of affiliative language and slight differences in assertive language. Language used more by self-identified females was interpersonally warmer, more compassionate, polite, and-contrary to previous findings-slightly more assertive in their language use, whereas language used more by self-identified males was colder, more hostile, and impersonal. Computational linguistic analysis combined with methods to automatically label topics offer means for testing psychological theories unobtrusively at large scale.

  4. Climate change and bird reproduction: warmer springs benefit breeding success in boreal forest grouse.

    Science.gov (United States)

    Wegge, Per; Rolstad, Jørund

    2017-11-15

    Global warming is predicted to adversely affect the reproduction of birds, especially in northern latitudes. A recent study in Finland inferred that declining populations of black grouse, Tetrao tetrix, could be attributed to advancement of the time of mating and chicks hatching too early-supporting the mismatch hypothesis. Here, we examine the breeding success of sympatric capercaillie, T. urogallus, and black grouse over a 38-year period in southeast Norway. Breeding season temperatures increased, being most pronounced in April. Although the onset of spring advanced nearly three weeks, the peak of mating advanced only 4-5 days. In contrast to the result of the Finnish study, breeding success increased markedly in both species (capercaillie: 62%, black grouse: 38%). Both brood frequency and brood size increased during the study period, but significantly so only for brood frequency in capercaillie. Whereas the frequency of capercaillie broods was positively affected by rising temperatures, especially during the pre-hatching period, this was not the case in black grouse. Brood size, on the other hand, increased with increasing post-hatching temperatures in both species. Contrary to the prediction that global warming will adversely affect reproduction in boreal forest grouse, our study shows that breeding success was enhanced in warmer springs. © 2017 The Authors.

  5. Future summer mega-heatwave and record-breaking temperatures in a warmer France climate

    Science.gov (United States)

    Bador, Margot; Terray, Laurent; Boé, Julien; Somot, Samuel; Alias, Antoinette; Gibelin, Anne-Laure; Dubuisson, Brigitte

    2017-07-01

    This study focuses on future very hot summers associated with severe heatwaves and record-breaking temperatures in France. Daily temperature observations and a pair of historical and scenario (greenhouse gas radiative concentration pathway 8.5) simulations with the high-resolution (∼12.5 km) ALADIN regional climate model provide a robust framework to examine the spatial distribution of these extreme events and their 21st century evolution. Five regions are identified with an extreme event spatial clustering algorithm applied to observed temperatures. They are used to diagnose the 21st century heatwave spatial patterns. In the 2070s, we find a simulated mega-heatwave as severe as the 2003 observed heatwave relative to its contemporaneous climate. A 20-member initial condition ensemble is used to assess the sensitivity of this future heatwave to the internal variability in the regional climate model and to pre-existing land surface conditions. Even in a much warmer and drier climate in France, late spring dry land conditions may lead to a significant amplification of summer extreme temperatures and heatwave intensity through limitations in evapotranspiration. By 2100, the increase in summer temperature maxima exhibits a range from 6 °C to almost 13 °C in the five regions in France, relative to historical maxima. These projections are comparable with the estimates given by a large number of global climate models.

  6. Impact of warmer weather on electricity sector emissions due to building energy use

    Science.gov (United States)

    Meier, Paul; Holloway, Tracey; Patz, Jonathan; Harkey, Monica; Ahl, Doug; Abel, David; Schuetter, Scott; Hackel, Scott

    2017-06-01

    Most US energy consumption occurs in buildings, with cooling demands anticipated to increase net building electricity use under warmer conditions. The electricity generation units that respond to this demand are major contributors to sulfur dioxide (SO2) and nitrogen oxides (NOx), both of which have direct impacts on public health, and contribute to the formation of secondary pollutants including ozone and fine particulate matter. This study quantifies temperature-driven changes in power plant emissions due to increased use of building air conditioning. We compare an ambient temperature baseline for the Eastern US to a model-calculated mid-century scenario with summer-average temperature increases ranging from 1 C to 5 C across the domain. We find a 7% increase in summer electricity demand and a 32% increase in non-coincident peak demand. Power sector modeling, assuming only limited changes to current generation resources, calculated a 16% increase in emissions of NOx and an 18% increase in emissions of SO2. There is a high level of regional variance in the response of building energy use to climate, and the response of emissions to associated demand. The East North Central census region exhibited the greatest sensitivity of energy demand and associated emissions to climate.

  7. Women are Warmer but No Less Assertive than Men: Gender and Language on Facebook.

    Directory of Open Access Journals (Sweden)

    Gregory Park

    Full Text Available Using a large social media dataset and open-vocabulary methods from computational linguistics, we explored differences in language use across gender, affiliation, and assertiveness. In Study 1, we analyzed topics (groups of semantically similar words across 10 million messages from over 52,000 Facebook users. Most language differed little across gender. However, topics most associated with self-identified female participants included friends, family, and social life, whereas topics most associated with self-identified male participants included swearing, anger, discussion of objects instead of people, and the use of argumentative language. In Study 2, we plotted male- and female-linked language topics along two interpersonal dimensions prevalent in gender research: affiliation and assertiveness. In a sample of over 15,000 Facebook users, we found substantial gender differences in the use of affiliative language and slight differences in assertive language. Language used more by self-identified females was interpersonally warmer, more compassionate, polite, and-contrary to previous findings-slightly more assertive in their language use, whereas language used more by self-identified males was colder, more hostile, and impersonal. Computational linguistic analysis combined with methods to automatically label topics offer means for testing psychological theories unobtrusively at large scale.

  8. Intense precipitation extremes in a warmer climate: results from CMIP5 models

    Science.gov (United States)

    scoccimarro, enrico; gualdi, silvio; bellucci, alessio; zampieri, matteo; navarra, antonio

    2013-04-01

    In this work the authors investigate possible changes in the intensity of extreme precipitation events under a warmer climate, using the results of a set of 20 climate models taking part to the Coupled Model Intercomparison Project phase 5 effort (CMIP5). Future changes are evaluated as the epoch difference between the last four decades of the 21st and the 20th Century assuming the Representative Concentration Pathway RCP8.5 scenario. As a measure of the intensity associated with extreme precipitation events, we use the difference between the 99th and the 90th percentiles. Despite a slight tendency to underestimate the observed extreme precipitation intensity, the considered CMIP5 models well represent the observed patterns during both summer and winter seasons for the 1997-2005 period. Future changes in average precipitation are consistent with previous findings based on CMIP3 models. CMIP5 models show a projected increase for the end of the twenty-first century of the intensity of the extreme precipitations, particularly pronounced over India, South East Asia, Indonesia and Central Africa during boreal summer, as well as over South America and the southern Africa during boreal winter. These changes are consistent with a strong increase of the column integrated water content availability over the afore mentioned regions.

  9. Biomass changes and trophic amplification of plankton in a warmer ocean

    KAUST Repository

    Chust, Guillem

    2014-05-07

    Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or more trophic pathways. We have employed 3-D coupled physical-biogeochemical models to explore ecosystem responses to climate change with a focus on trophic amplification. The response of phytoplankton and zooplankton to global climate-change projections, carried out with the IPSL Earth System Model by the end of the century, is analysed at global and regional basis, including European seas (NE Atlantic, Barents Sea, Baltic Sea, Black Sea, Bay of Biscay, Adriatic Sea, Aegean Sea) and the Eastern Boundary Upwelling System (Benguela). Results indicate that globally and in Atlantic Margin and North Sea, increased ocean stratification causes primary production and zooplankton biomass to decrease in response to a warming climate, whilst in the Barents, Baltic and Black Seas, primary production and zooplankton biomass increase. Projected warming characterized by an increase in sea surface temperature of 2.29 ± 0.05 °C leads to a reduction in zooplankton and phytoplankton biomasses of 11% and 6%, respectively. This suggests negative amplification of climate driven modifications of trophic level biomass through bottom-up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. Simulations suggest negative amplification is the dominant response across 47% of the ocean surface and prevails in the tropical oceans; whilst positive trophic amplification prevails in the Arctic and Antarctic oceans. Trophic attenuation is projected in temperate seas. Uncertainties in ocean plankton projections, associated to the use of single global and

  10. Biomass changes and trophic amplification of plankton in a warmer ocean.

    Science.gov (United States)

    Chust, Guillem; Allen, J Icarus; Bopp, Laurent; Schrum, Corinna; Holt, Jason; Tsiaras, Kostas; Zavatarelli, Marco; Chifflet, Marina; Cannaby, Heather; Dadou, Isabelle; Daewel, Ute; Wakelin, Sarah L; Machu, Eric; Pushpadas, Dhanya; Butenschon, Momme; Artioli, Yuri; Petihakis, George; Smith, Chris; Garçon, Veronique; Goubanova, Katerina; Le Vu, Briac; Fach, Bettina A; Salihoglu, Baris; Clementi, Emanuela; Irigoien, Xabier

    2014-07-01

    Ocean warming can modify the ecophysiology and distribution of marine organisms, and relationships between species, with nonlinear interactions between ecosystem components potentially resulting in trophic amplification. Trophic amplification (or attenuation) describe the propagation of a hydroclimatic signal up the food web, causing magnification (or depression) of biomass values along one or more trophic pathways. We have employed 3-D coupled physical-biogeochemical models to explore ecosystem responses to climate change with a focus on trophic amplification. The response of phytoplankton and zooplankton to global climate-change projections, carried out with the IPSL Earth System Model by the end of the century, is analysed at global and regional basis, including European seas (NE Atlantic, Barents Sea, Baltic Sea, Black Sea, Bay of Biscay, Adriatic Sea, Aegean Sea) and the Eastern Boundary Upwelling System (Benguela). Results indicate that globally and in Atlantic Margin and North Sea, increased ocean stratification causes primary production and zooplankton biomass to decrease in response to a warming climate, whilst in the Barents, Baltic and Black Seas, primary production and zooplankton biomass increase. Projected warming characterized by an increase in sea surface temperature of 2.29 ± 0.05 °C leads to a reduction in zooplankton and phytoplankton biomasses of 11% and 6%, respectively. This suggests negative amplification of climate driven modifications of trophic level biomass through bottom-up control, leading to a reduced capacity of oceans to regulate climate through the biological carbon pump. Simulations suggest negative amplification is the dominant response across 47% of the ocean surface and prevails in the tropical oceans; whilst positive trophic amplification prevails in the Arctic and Antarctic oceans. Trophic attenuation is projected in temperate seas. Uncertainties in ocean plankton projections, associated to the use of single global and

  11. The effect of non-local higher order stress to predict the nonlinear vibration behavior of carbon nanotube conveying viscous nanoflow

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadimehr, M., E-mail: mmohammadimehr@kashanu.ac.ir [Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, P.O. Box: 87317-53153, Kashan (Iran, Islamic Republic of); Mohammadi-Dehabadi, A.A. [Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, P.O. Box: 87317-53153, Kashan (Iran, Islamic Republic of); Department of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Maraghi, Z. Khoddami [Department of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, P.O. Box: 87317-53153, Kashan (Iran, Islamic Republic of)

    2017-04-01

    In this research, the effect of non-local higher order stress on the nonlinear vibration behavior of carbon nanotube conveying viscous nanoflow resting on elastic foundation is investigated. Physical intuition reveals that increasing nanoscale stress leads to decrease the stiffness of nanostructure which firstly established by Eringen's non-local elasticity theory (previous nonlocal method) while many of papers have concluded otherwise at microscale based on modified couple stress, modified strain gradient theories and surface stress effect. The non-local higher order stress model (new nonlocal method) is used in this article that has been studied by few researchers in other fields and the results from the present study show that the trend of the new nonlocal method and size dependent effect including modified couple stress theory is the same. In this regard, the nonlinear motion equations are derived using a variational principal approach considering essential higher-order non-local terms. The surrounded elastic medium is modeled by Pasternak foundation to increase the stability of system where the fluid flow may cause system instability. Effects of various parameters such as non-local parameter, elastic foundation coefficient, and fluid flow velocity on the stability and dimensionless natural frequency of nanotube are investigated. The results of this research show that the small scale parameter based on higher order stress help to increase the natural frequency which has been approved by other small scale theories such as strain gradient theory, modified couple stress theory and experiments, and vice versa for previous nonlocal method. This study may be useful to measure accurately the vibration characteristics of nanotubes conveying viscous nanoflow and to design nanofluidic devices for detecting blood Glucose.

  12. The effect of non-local higher order stress to predict the nonlinear vibration behavior of carbon nanotube conveying viscous nanoflow

    Science.gov (United States)

    Mohammadimehr, M.; Mohammadi-Dehabadi, A. A.; Maraghi, Z. Khoddami

    2017-04-01

    In this research, the effect of non-local higher order stress on the nonlinear vibration behavior of carbon nanotube conveying viscous nanoflow resting on elastic foundation is investigated. Physical intuition reveals that increasing nanoscale stress leads to decrease the stiffness of nanostructure which firstly established by Eringen's non-local elasticity theory (previous nonlocal method) while many of papers have concluded otherwise at microscale based on modified couple stress, modified strain gradient theories and surface stress effect. The non-local higher order stress model (new nonlocal method) is used in this article that has been studied by few researchers in other fields and the results from the present study show that the trend of the new nonlocal method and size dependent effect including modified couple stress theory is the same. In this regard, the nonlinear motion equations are derived using a variational principal approach considering essential higher-order non-local terms. The surrounded elastic medium is modeled by Pasternak foundation to increase the stability of system where the fluid flow may cause system instability. Effects of various parameters such as non-local parameter, elastic foundation coefficient, and fluid flow velocity on the stability and dimensionless natural frequency of nanotube are investigated. The results of this research show that the small scale parameter based on higher order stress help to increase the natural frequency which has been approved by other small scale theories such as strain gradient theory, modified couple stress theory and experiments, and vice versa for previous nonlocal method. This study may be useful to measure accurately the vibration characteristics of nanotubes conveying viscous nanoflow and to design nanofluidic devices for detecting blood Glucose.

  13. Forest phenology and a warmer climate - Growing season extension in relation to climatic provenance

    Energy Technology Data Exchange (ETDEWEB)

    Gunderson, Carla A [ORNL; Edwards, Nelson T [ORNL; Walker, Ashley V [ORNL; O' Hara, Keiran H [ORNL; Campion, Christina M [ORNL; Hanson, Paul J [ORNL

    2012-01-01

    Predicting forest responses to warming climates relies on assumptions about niche and temperature sensitivity that remain largely untested. Observational studies have related current and historical temperatures to phenological shifts, but experimental evidence is sparse, particularly for autumn responses. A five-year field experiment exposed four deciduous forest species from contrasting climates (Liquidambar styraciflua, Quercus rubra, Populus grandidentata, and Betula alleghaniensis) to air temperatures 2 and 4 C above ambient controls. Impacts of year-round warming on bud burst (BB), senescence and abscission were evaluated in relation to thermal provenance. Leaves emerged earlier in all species, by an average of 6-9 days at +2 and +4 C. Magnitude of advance varied with species and year, but was larger for the first 2 C increment than the second. The effect of warming increased with early BB, favoring Liquidambar, from the warmest climate, but even BB in northern species advanced, despite temperatures well beyond those of the realized niche. Treatment differences in BB were poorly explained by temperature sums, which increased with treatment. In autumn, chlorophyll was retained an average of 4 and 7 days longer in +2 and +4 C treatments, and abscission delayed by 8 and 13 days. Species differences in autumn responses were marginally significant. Growing seasons in the warmer atmospheres were 6 - 28 days longer, with the least impact in Quercus. Results are compared with a 16-year record of canopy onset and offset in a nearby upland deciduous forest, where BB showed similar responsiveness to spring temperatures (2 - 4 days C-1). Offset dates in the stand tracked August-September temperatures, except when late summer drought caused premature senescence. The common garden-like experimental approach provides evidence that warming alone extends the growing season, at both ends, even if stand-level impacts are complicated by other environmental factors.

  14. Warmer weather linked to tick attack and emergence of severe rickettsioses.

    Science.gov (United States)

    Parola, Philippe; Socolovschi, Cristina; Jeanjean, Luc; Bitam, Idir; Fournier, Pierre-Edouard; Sotto, Albert; Labauge, Pierre; Raoult, Didier

    2008-01-01

    The impact of climate on the vector behaviour of the worldwide dog tick Rhipicephalus sanguineus is a cause of concern. This tick is a vector for life-threatening organisms including Rickettsia rickettsii, the agent of Rocky Mountain spotted fever, R. conorii, the agent of Mediterranean spotted fever, and the ubiquitous emerging pathogen R. massiliae. A focus of spotted fever was investigated in France in May 2007. Blood and tissue samples from two patients were tested. An entomological survey was organised with the study of climatic conditions. An experimental model was designed to test the affinity of Rh. sanguineus for biting humans in variable temperature conditions. Serological and/or molecular tools confirmed that one patient was infected by R. conorii, whereas the other was infected by R. massiliae. Dense populations of Rh. sanguineus were found. They were infected with new genotypes of clonal populations of either R. conorii (24/133; 18%) or R. massiliae (13/133; 10%). April 2007 was the warmest since 1950, with summer-like temperatures. We show herein that the human affinity of Rh. sanguineus was increased in warmer temperatures. In addition to the originality of theses cases (ophthalmic involvements, the second reported case of R. massiliae infection), we provide evidence that this cluster of cases was related to a warming-mediated increase in the aggressiveness of Rh. sanguineus, leading to increased human attacks. From a global perspective, we predict that as a result of globalisation and warming, more pathogens transmitted by the brown dog tick may emerge in the future.

  15. Thermo-mechanical vibration analysis of a single-walled carbon nanotube embedded in an elastic medium based on higher-order shear deformation beam theory

    Energy Technology Data Exchange (ETDEWEB)

    Ebrahimi, Farzad; Salari, Erfan [Imam Khomeini International University, Qazvin (Iran, Islamic Republic of)

    2015-09-15

    In this study, the thermal effect on the free vibration characteristics of embedded Single-walled carbon nanotubes (SWCNTs) based on the size-dependent Reddy higher order shear deformation beam theory subjected to in-plane thermal loading is investigated by presenting a Navier-type solution and employing a semi-analytical Differential transform method (DTM) for the first time. In addition, the exact nonlocal Reddy beam theory solution presented here should be useful to engineers designing nanoelectromechanical devices. The small scale effect is considered based on nonlocal elasticity theory of Eringen. The nonlocal equations of motion are derived through Hamilton's principle, and they are solved by applying DTM. Numerical results reveal that the proposed modeling and semi-analytical approach can provide more accurate frequency results of the SWCNTs compared to analytical results and some cases in the literature. The detailed mathematical derivations are presented, and numerical investigations are performed, whereas emphasis is placed on investigating the effect of several parameters such as small-scale effects, boundary conditions, mode number, thickness ratio, temperature change, and Winkler spring modulus on the natural frequencies of the SWCNTs in detail. The vibration behavior of SWCNTs is significantly influenced by these effects. Results indicate that the inclusion of size effect results in a decrease in nanobeam stiffness and leads to a decrease in natural frequency. Numerical results are presented to serve as benchmarks for future analyses of SWCNTs.

  16. Tibetan Plateau Geladaindong black carbon ice core record (1843–1982: Recent increases due to higher emissions and lower snow accumulation

    Directory of Open Access Journals (Sweden)

    Jenkins Matthew

    2016-09-01

    Full Text Available Black carbon (BC deposited on snow and glacier surfaces can reduce albedo and lead to accelerated melt. An ice core recovered from Guoqu glacier on Mt. Geladaindong and analyzed using a Single Particle Soot Photometer (SP2 provides the first long-term (1843–1982 record of BC from the central Tibetan Plateau. Post 1940 the record is characterized by an increased occurrence of years with above average BC, and the highest BC values of the record. The BC increase in recent decades is likely caused by a combination of increased emissions from regional BC sources, and a reduction in snow accumulation. Guoqu glacier has received no net ice accumulation since the 1980s, and is a potential example of a glacier where an increase in the equilibrium line altitude is exposing buried high impurity layers. That BC concentrations in the uppermost layers of the Geladaindong ice core are not substantially higher relative to deeper in the ice core suggests that some of the BC that must have been deposited on Guoqu glacier via wet or dry deposition between 1983 and 2005 has been removed from the surface of the glacier, potentially via supraglacial or englacial meltwater.

  17. Getting warmer: Looking for a way out of the climate impasse

    Energy Technology Data Exchange (ETDEWEB)

    Flavin, C.; Tunali, O.

    1995-03-01

    In the three years since the Climate Change Treaty was signed, the world`s governments have failed to respond effectively to the threat of climate change. Most industrial countries have interpreted the treaty`s ambiguous targets in ways that require no disruptions of their favored industries - many still give enormous subsidies to oil and coal, and none have adopted sizable carbon dioxide taxes. This article describes what has gone wrong - public confusion and opposition from powerful industries and labor groups which extract, process and sell fossil fuels - and the extent of the problem in different developed countries in Europe and North America. Also included is a discussion of the problems of developing countries and attempts to help these countries to reduce carbon emissions. A list of suggestions to make the treaty work are given.

  18. Production of medium-chain fatty acids and higher alcohols by a synthetic co-culture grown on carbon monoxide or syngas.

    Science.gov (United States)

    Diender, Martijn; Stams, Alfons J M; Sousa, Diana Z

    2016-01-01

    Synthesis gas, a mixture of CO, H2, and CO2, is a promising renewable feedstock for bio-based production of organic chemicals. Production of medium-chain fatty acids can be performed via chain elongation, utilizing acetate and ethanol as main substrates. Acetate and ethanol are main products of syngas fermentation by acetogens. Therefore, syngas can be indirectly used as a substrate for the chain elongation process. Here, we report the establishment of a synthetic co-culture consisting of Clostridium autoethanogenum and Clostridium kluyveri. Together, these bacteria are capable of converting CO and syngas to a mixture of C4 and C6 fatty acids and their respective alcohols. The co-culture is able to grow using solely CO or syngas as a substrate, and presence of acetate significantly stimulated production rates. The co-culture produced butyrate and caproate at a rate of 8.5 ± 1.1 and 2.5 ± 0.63 mmol/l/day, respectively. Butanol and hexanol were produced at a rate of 3.5 ± 0.69 and 2.0 ± 0.46 mmol/l/day, respectively. The pH was found to be a major factor during cultivation, influencing the growth performance of the separate strains and caproate toxicity. This co-culture poses an alternative way to produce medium-chain fatty acids and higher alcohols from carbon monoxide or syngas and the process can be regarded as an integration of syngas fermentation and chain elongation in one growth vessel.

  19. Impact of the 3 °C temperature rise on bacterial growth and carbon transfer towards higher trophic levels: Empirical models for the Adriatic Sea

    Science.gov (United States)

    Šolić, Mladen; Krstulović, Nada; Šantić, Danijela; Šestanović, Stefanija; Kušpilić, Grozdan; Bojanić, Natalia; Ordulj, Marin; Jozić, Slaven; Vrdoljak, Ana

    2017-09-01

    The Mediterranean Sea (including the Adriatic Sea) has been identified as a 'hotspot' for climate change, with the prediction of the increase in water temperature of 2-4 °C over the next few decades. Being mainly oligotrophic, and strongly phosphorus limited, the Adriatic Sea is characterized by the important role of the microbial food web in production and transfer of biomass and energy towards higher trophic levels. We hypothesized that predicted 3 °C temperature rise in the near future might cause an increase of bacterial production and bacterial losses to grazers, which could significantly enlarge the trophic base for metazoans. This empirical study is based on a combined 'space-for-time substitution' analysis (which is performed on 3583 data sets) and on an experimental approach (36 in situ grazing experiments performed at different temperatures). It showed that the predicted 3 °C temperature increase (which is a result of global warming) in the near future could cause a significant increase in bacterial growth at temperatures lower than 16 °C (during the colder winter-spring period, as well as in the deeper layers). The effect of temperature on bacterial growth could be additionally doubled in conditions without phosphorus limitation. Furthermore, a 3 °C increase in temperature could double the grazing on bacteria by heterotrophic nanoflagellate (HNF) and ciliate predators and it could increase the proportion of bacterial production transferred to the metazoan food web by 42%. Therefore, it is expected that global warming may further strengthen the role of the microbial food web in a carbon cycle in the Adriatic Sea.

  20. Why is the electroanalytical performance of carbon paste electrodes involving an ionic liquid binder higher than paraffinic binders? A simulation investigation.

    Science.gov (United States)

    Ghatee, M H; Namvar, S; Zolghadr, A R; Moosavi, F

    2015-10-14

    Recently, carbon paste electrodes (CPE) fabricated using an ionic liquid (IL) binder have shown enhanced electroanalytical performance over conventional paraffinic binders. Molecular dynamics (MD) simulations of graphite mixed with ionic liquid and with paraffin binder can unravel the potential atomistic factors responsible for such enhancement. Based on an experimentally optimized binder/graphite mass ratio, which has been reported to be crucial for such a performance, comprehensive simulations (at 323 K) are performed with the ensembles involving an ionic liquid binder (1-butyl-3-methylimidazolium hexafluorophosphate, [C4mim]PF6) and a paraffin binder (n-C20H42) mixed with graphite comprising large-size hexagonal-shaped double graphene plates. Structural analysis indicates both binders form only a monolayer on the graphite surface, covering the surface locally by IL but all-encompassing by paraffin. With charged and uncharged graphite, the IL monolayer tends to cover mainly the graphite center without approaching the edge planes. On the contrary, a monolayer of the paraffin binder covers uniformly the center, near the center, and the edge planes. Cations and anions of the IL form well-defined two dimensional pentagonal matrixes with characteristic high adsorption energy, almost 2.4 times higher than paraffin adsorption. The cation and anion coordination ability of the IL is responsible for such a local distribution. The simulation of these phenomena under experimental conditions unravels strong two-dimensional coordination properties inherent to the ionic liquid when distributed over the graphite surface. This direct MD simulation comparison of the IL properties with an organic liquid counterpart, made for the first time, can be used to explain the high electroanalytical performance (electron transfer) of CPEs involving an IL binder over paraffin binders.

  1. Potential costs of acclimatization to a warmer climate: growth of a reef coral with heat tolerant vs. sensitive symbiont types.

    Directory of Open Access Journals (Sweden)

    Alison Jones

    Full Text Available One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change.

  2. Students’ perceived heat-health symptoms increased with warmer classroom temperatures

    CSIR Research Space (South Africa)

    Bidassey-Manilal, S

    2016-01-01

    Full Text Available one hour on any day. There were statistically significant correlations, when controlling for school cluster effect and time of day, between indoor temperatures ¥32 C and students who felt tired and found it hard to breathe. Consistently higher indoor...

  3. Increased microbial activity in a warmer and wetter climate enhances the risk of coastal hypoxia.

    Science.gov (United States)

    Nydahl, Anna; Panigrahi, Satya; Wikner, Johan

    2013-08-01

    The coastal zone is the most productive area of the marine environment and the area that is most exposed to environmental drivers associated with human pressures in a watershed. In dark bottle incubation experiments, we investigated the short-term interactive effects of changes in salinity, temperature and riverine dissolved organic matter (rDOM) on microbial respiration, growth and abundance in an estuarine community. An interaction effect was found for bacterial growth, where the assimilation of rDOM increased at higher salinities. A 3 °C rise in the temperature had a positive effect on microbial respiration. A higher concentration of DOM consistently enhanced respiration and bacterial abundance, while an increase in temperature reduced bacterial abundance. The latter result was most likely caused by a positive interaction effect of temperature, salinity and rDOM on the abundance of bacterivorous flagellates. Elevated temperature and precipitation, causing increased discharges of rDOM and an associated lowered salinity, will therefore primarily promote bacterial respiration, growth and bacterivore abundance. Our results suggest a positive net outcome for microbial activity under the projected climate change, driven by different, partially interacting environmental factors. Thus, hypoxia in coastal zones may increase due to enhanced respiration caused by higher temperatures and rDOM discharge acting synergistically. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  4. Elevated CO2 reduced floret death in wheat under warmer average temperatures and terminal drought.

    Directory of Open Access Journals (Sweden)

    Eduardo eDias de Oliveira

    2015-11-01

    Full Text Available Elevated CO2 often increases grain yield in wheat by enhancing grain number per ear, which can result from an increase in the potential number of florets or a reduction in the death of developed florets. The hypotheses that elevated CO2 reduces floret death rather than increases floret development, and that grain size in a genotype with more grains per unit area is limited by the rate of grain filling, were tested in a pair of sister lines contrasting in tillering capacity (restricted- vs free-tillering. The hypotheses were tested under elevated CO2, combined with +3 C above ambient temperature and terminal drought, using specialized field tunnel houses. Elevated CO2 increased net leaf photosynthetic rates and likely the availability of carbon assimilates, which significantly reduced the rates of floret death and increased the potential number of grains at anthesis in both sister lines by an average of 42%. The restricted-tillering line had faster grain-filling rates than the free-tillering line because the free-tillering line had more grains to fill. Furthermore, grain-filling rates were faster under elevated CO2 and +3 C above ambient. Terminal drought reduced grain yield in both lines by 19%. Elevated CO2 alone increased the potential number of grains, but a trade-off in yield components limited grain yield in the free-tillering line. This emphasizes the need for breeding cultivars with a greater potential number of florets, since this was not affected by the predicted future climate variables.

  5. Designing urban spaces and buildings to improve sustainability and quality of life in a warmer world

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Claire; Levermore, Geoff [Built Environment Research Group, University of Manchester, PO Box 88, Sackville Street, Manchester M60 1QD (United Kingdom)

    2008-12-15

    It is in cities that the negative impacts of a warming climate will be felt most strongly. The summer time comfort and well-being of the urban population will become increasingly compromised under future scenarios for climate change and urbanisation. In contrast to rural areas, where night-time relief from high daytime temperatures occurs as heat is lost to the sky, the city environment stores and traps heat and offers little respite from high temperatures. This urban heat island effect is responsible for temperature differences of up to 7 C between cities and the country in the UK. We already have experience of the potential hazards of these higher temperatures. The majority of heat-related fatalities during the summer of 2003 were in urban areas. This means that the cooling of the urban environment is a high priority for urban planners and designers. Proven ways of doing this include altering the urban microclimate by modifying its heat absorption and emission, for example through urban greening, the use of high-reflectivity materials, and by increasing openness to allow cooling winds. Buildings themselves can also deliver improved comfort and higher levels of sustainability by taking advantage of exemplary facade, glazing and ventilation designs. In addition, changed behaviour by building occupants can help keep urban areas cool. The technology to reduce the future vulnerability of city dwellers to thermal discomfort is already largely in existence. But there is a need for complementary policy and planning commitments to manage its implementation, especially in existing buildings and urban areas. (author)

  6. Would behavioral thermoregulation enable pregnant viviparous tropical lizards to cope with a warmer world?

    Science.gov (United States)

    López-Alcaide, Saúl; Nakamura, Miguel; Smith, Eric N; Martínez-Meyer, Enrique

    2017-09-01

    Sceloporus lizards depend on external heat to achieve their preferred temperature (T sel ) for performing physiological processes. Evidence both in the field and laboratory indicates that pregnant females of this Genus select body temperatures (T b ) lower than 34 °C as higher temperatures may be lethal to embryos. Therefore, thermoregulation is crucial for successful embryo development. Given the increase in global air temperature, it is expected that the first compensatory response of species that inhabit tropical climates will be behavioral thermoregulation. We tested whether viviparous Sceloporus formosus group lizards in the wild exhibited differences in thermoregulatory behavior to achieve the known T sel for developing embryos regardless of local thermal conditions. We quantified field active body temperature, thermoregulatory behavior mechanisms (time of sighting, microhabitat used and basking time) and available microhabitat thermal conditions (i.e. operative temperature) for 10 lizard species during gestation, distributed along an altitudinal gradient. We applied both conventional and phylogenic analyses to explore whether T b or behavioral thermoregulation could be regulated in response to different thermal conditions. These species showed no significant differences in field T b during gestation regardless of local thermal conditions. In contrast, they exhibited significant differences in their behavioral thermoregulation associated with local environmental conditions. Based on these observations, the differences in thermoregulatory behavior identified are interpreted as compensatory adjustments to local thermal conditions. We conclude that these species may deal with higher temperatures predicted for the tropics by modulating their thermoregulatory behavior. © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

  7. The effect of the pathway to a two degrees warmer world on the regional temperature change of Europe

    Directory of Open Access Journals (Sweden)

    Cathrine Fox Maule

    2017-08-01

    Full Text Available The purpose of this study is to investigate if the pathway to reach a 2 degree warmer world influences the regional climate in Europe at the time of 2 degrees of global warming above the pre-industrial level. We have investigated this using climate change data from ensembles of both Global Climate Models and Regional Climate Models. We compare the change of regional temperature in Europe to the global temperature change for different emission scenarios, following the IPCC Representative Concentration Pathways (RCP, to see if the pathway has any influence. We find that there is a small but significant difference in the regional temperature change, but the effect is small compared to internal variability on the timescales involved in reaching +2 degrees for the investigated emission scenarios. From an adaptation point of view, reaching +2 degrees as slowly as possible will obviously allow for a longer time period to implement adaptation measures to mitigate the effect of climate change.

  8. Subtropical Low Cloud Response to a Warmer Climate in an Superparameterized Climate Model: Part I. Regime Sorting and Physical Mechanisms

    Directory of Open Access Journals (Sweden)

    Peter N Blossey

    2009-07-01

    Full Text Available The subtropical low cloud response to a climate with SST uniformly warmed by 2 K is analyzed in the SP- CAM superparameterized climate model, in which each grid column is replaced by a two-dimensional cloud-resolving model (CRM. Intriguingly, SP-CAM shows substantial low cloud increases over the subtropical oceans in the warmer climate. The paper aims to understand the mechanism for these increases. The subtropical low cloud increase is analyzed by sorting grid-column months of the climate model into composite cloud regimes using percentile ranges of lower tropospheric stability (LTS. LTS is observed to be well correlated to subtropical low cloud amount and boundary layer vertical structure. The low cloud increase in SP-CAM is attributed to boundary-layer destabilization due to increased clear-sky radiative cooling in the warmer climate. This drives more shallow cumulus convection and a moister boundary layer, inducing cloud increases and further increasing the radiative cooling. The boundary layer depth does not change substantially, due to compensation between increased radiative cooling (which promotes more turbulent mixing and boundary-layer deepening and slight strengthening of the boundary-layer top inversion (which inhibits turbulent entrainment and promotes a shallower boundary layer. The widespread changes in low clouds do not appear to be driven by changes in mean subsidence.
    In a companion paper we use column-mode CRM simulations based on LTS-composite profiles to further study the low cloud response mechanisms and to explore the sensitivity of low cloud response to grid resolution in SP-CAM.

  9. Optimal Regulation of the Balance between Productivity and Overwintering of Perennial Grasses in a Warmer Climate

    Directory of Open Access Journals (Sweden)

    Åshild Ergon

    2017-02-01

    Full Text Available Seasonal growth patterns of perennial plants are linked to patterns of acclimation and de-acclimation to seasonal stresses. The timing of cold acclimation (development of freezing resistance and leaf growth cessation in autumn, and the timing of de-acclimation and leaf regrowth in spring, is regulated by seasonal cues in the environment, mainly temperature and light factors. Warming will lead to new combinations of these cues in autumn and spring. Extended thermal growing seasons offer a possibility for obtaining increased yields of perennial grasses at high latitudes. Increased productivity in the autumn may not be possible in all high latitude regions due to the need for light during cold acclimation and the need for accumulating a carbohydrate storage prior to winter. There is more potential for increased yields in spring due to the availability of light, but higher probability of freezing events in earlier springs would necessitate a delay of de-acclimation, or an ability to rapidly re-acclimate. In order to optimize the balance between productivity and overwintering in the future, the regulation of growth and acclimation processes may have to be modified. Here, the current knowledge on the coordinated regulation of growth and freezing resistance in perennial grasses is reviewed.

  10. Students’ Perceived Heat-Health Symptoms Increased with Warmer Classroom Temperatures

    Directory of Open Access Journals (Sweden)

    Shalin Bidassey-Manilal

    2016-06-01

    Full Text Available Temperatures in Africa are expected to increase by the end of the century. Heat-related health impacts and perceived health symptoms are potentially a problem, especially in public schools with limited resources. Students (n = 252 aged ~14–18 years from eight high schools completed an hourly heat-health symptom log over 5 days. Data loggers measured indoor classroom temperatures. A high proportion of students felt tired (97.2%, had low concentration (96.8% and felt sleepy (94.1% during at least one hour on any day. There were statistically significant correlations, when controlling for school cluster effect and time of day, between indoor temperatures ≥32 °C and students who felt tired and found it hard to breathe. Consistently higher indoor classroom temperatures were observed in classrooms constructed of prefabricated asbestos sheeting with corrugated iron roof and converted shipping container compared to brick classrooms. Longitudinal studies in multiple seasons and different classroom building types are needed.

  11. Students' Perceived Heat-Health Symptoms Increased with Warmer Classroom Temperatures.

    Science.gov (United States)

    Bidassey-Manilal, Shalin; Wright, Caradee Y; Engelbrecht, Jacobus C; Albers, Patricia N; Garland, Rebecca M; Matooane, Mamopeli

    2016-06-07

    Temperatures in Africa are expected to increase by the end of the century. Heat-related health impacts and perceived health symptoms are potentially a problem, especially in public schools with limited resources. Students (n = 252) aged ~14-18 years from eight high schools completed an hourly heat-health symptom log over 5 days. Data loggers measured indoor classroom temperatures. A high proportion of students felt tired (97.2%), had low concentration (96.8%) and felt sleepy (94.1%) during at least one hour on any day. There were statistically significant correlations, when controlling for school cluster effect and time of day, between indoor temperatures ≥32 °C and students who felt tired and found it hard to breathe. Consistently higher indoor classroom temperatures were observed in classrooms constructed of prefabricated asbestos sheeting with corrugated iron roof and converted shipping container compared to brick classrooms. Longitudinal studies in multiple seasons and different classroom building types are needed.

  12. Building when the climate gets warmer; Bauen, wenn das Klima waermer wird - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, C. U. [Energieplaner, CUB Architektur Energie Umwelt, Zuerich (Switzerland); Steinemann, U. [Ingenieurbuero Urs Steinemann, Wollerau (Switzerland); Nipkow, J. [Arena, Arbeitsgemeinschaft Energie-Alternativen, Zuerich (Switzerland)

    2007-07-01

    This final report for the Swiss Federal Office of Energy (SFOE), takes a look at how the building process will have to take account of climate change with higher summer temperatures in Switzerland. The authors consider the situation as being in strong contrast to the past in Switzerland, when attention was devoted to energy demand in buildings during the winter. Today there is a new focus with the anticipation of increasingly frequent, extended hot spells in summer. The goal of this investigation is to analyse and present economic measures to assure a high level of summer comfort with a reduced demand for electricity under these changing conditions. Strategies with respect to construction, technology and operation are addressed. The current spread of technically questionable and inefficient room air conditioning units in residential and commercial buildings is considered as being strongly reminiscent of a dangerous, analogous case in the past, when small electric heaters became widespread. A largely untapped potential exists for increasing the efficiency of air conditioning and chiller technologies for both central systems and room units by the careful use of small temperature differences. Several new and unconventional solution paths are discussed, including high-efficiency room air conditioners, solar cooling equipment, balanced mechanical ventilation, phase-change materials, thermal storage, etc., all aimed at reducing electricity consumption. The expected additional electricity demand of around 1.9 TWh annually for ventilation and air conditioning is commented on.

  13. Increased fitness of a key appendicularian zooplankton species under warmer, acidified seawater conditions.

    Directory of Open Access Journals (Sweden)

    Jean-Marie Bouquet

    Full Text Available Ocean warming and acidification (OA may alter the fitness of species in marine pelagic ecosystems through community effects or direct physiological impacts. We used the zooplanktonic appendicularian, Oikopleura dioica, to assess temperature and pH effects at mesocosm and microcosm scales. In mesocosms, both OA and warming positively impacted O. dioica abundance over successive generations. In microcosms, the positive impact of OA, was observed to result from increased fecundity. In contrast, increased pH, observed for example during phytoplankton blooms, reduced fecundity. Oocyte fertility and juvenile development were equivalent under all pH conditions, indicating that the positive effect of lower pH on O. dioica abundance was principally due to increased egg number. This effect was influenced by food quantity and quality, supporting possible improved digestion and assimilation at lowered pH. Higher temperature resulted in more rapid growth, faster maturation and earlier reproduction. Thus, increased temperature and reduced pH had significant positive impacts on O. dioica fitness through increased fecundity and shortened generation time, suggesting that predicted future ocean conditions may favour this zooplankton species.

  14. Greater impact of extreme drought on photosynthesis of grasslands exposed to a warmer climate in spite of acclimation.

    Science.gov (United States)

    Zavalloni, Costanza; Gielen, Birgit; De Boeck, Hans J; Lemmens, Catherine M H M; Ceulemans, Reinhart; Nijs, Ivan

    2009-05-01

    In view of the projected increase in the frequency of extreme events during this century, we investigated the impact of a drought extreme on leaf ecophysiological parameters and carbon isotope composition (delta(13)C) of grassland communities with species richness (S) of one, three or nine species. The communities, grown for 3 years at either ambient air temperatures (ambient T(air)) or ambient T(air) + 3 degrees C (elevated T(air)), were additionally subjected to an imposed drought by withholding water for 24 days. During the previous 3 years equal precipitation was applied in both temperature treatments, thus communities at elevated T(air) had experienced more frequent, mild droughts. However, it was unknown whether this resulted in a higher resistance for facing extreme droughts. At similar soil matric potentials stomatal conductance (g(s)) and transpiration (Tr) were higher at elevated than ambient T(air), indicating acclimation to lower soil water content. Despite the stomatal acclimation observed, plants in elevated T(air) showed a lower resistance to the drought extreme as indicated by their lower photosynthetic rate (A(max)), g(s) and Tr during the entire duration of the drought extreme. Lower values for A(max), Tr and g(s) were also recorded in species at S = 3 as compared with species at S = 1 for both temperature treatments, but no further differences with S = 9 suggesting that stress was not alleviated at higher S-levels. The discrimination of (13)C was poorly correlated with measurements of instantaneous leaf water-use efficiency (A(max)/Tr) and, with this time scale and sampling method, it was not possible to detect any potential change in plant water-use efficiency using leaf delta(13)C.

  15. An underestimated record breaking event – why summer 1540 was likely warmer than 2003

    Directory of Open Access Journals (Sweden)

    O. Wetter

    2013-01-01

    Full Text Available The heat of summer 2003 in Western and Central Europe was claimed to be unprecedented since the Middle Ages on the basis of grape harvest data (GHD and late wood maximum density (MXD data from trees in the Alps. This paper shows that the authors of these studies overlooked the fact that the heat and drought in Switzerland in 1540 likely exceeded the amplitude of the previous hottest summer of 2003, because the persistent temperature and precipitation anomaly in that year, described in an abundant and coherent body of documentary evidence, severely affected the reliability of GHD and tree-rings as proxy-indicators for temperature estimates. Spring–summer (AMJJ temperature anomalies of 4.7 °C to 6.8 °C being significantly higher than in 2003 were assessed for 1540 from a new long Swiss GHD series (1444 to 2011. During the climax of the heat wave in early August the grapes desiccated on the vine, which caused many vine-growers to interrupt or postpone the harvest despite full grape maturity until after the next spell of rain. Likewise, the leaves of many trees withered and fell to the ground under extreme drought stress as would usually be expected in late autumn. It remains to be determined by further research whether and how far this result obtained from local analyses can be spatially extrapolated. Based on the temperature estimates for Switzerland it is assumed from a great number of coherent qualitative documentary evidence about the outstanding heat drought in 1540 that AMJJ temperatures were likely more extreme in neighbouring regions of Western and Central Europe than in 2003. Considering the significance of soil moisture deficits for record breaking heat waves, these results still need to be validated with estimated seasonal precipitation. It is concluded that biological proxy data may not properly reveal record breaking heat and drought events. Such assessments thus need to be complemented with the critical study of contemporary

  16. An underestimated record breaking event - why summer 1540 was likely warmer than 2003

    Science.gov (United States)

    Wetter, O.; Pfister, C.

    2013-01-01

    The heat of summer 2003 in Western and Central Europe was claimed to be unprecedented since the Middle Ages on the basis of grape harvest data (GHD) and late wood maximum density (MXD) data from trees in the Alps. This paper shows that the authors of these studies overlooked the fact that the heat and drought in Switzerland in 1540 likely exceeded the amplitude of the previous hottest summer of 2003, because the persistent temperature and precipitation anomaly in that year, described in an abundant and coherent body of documentary evidence, severely affected the reliability of GHD and tree-rings as proxy-indicators for temperature estimates. Spring-summer (AMJJ) temperature anomalies of 4.7 °C to 6.8 °C being significantly higher than in 2003 were assessed for 1540 from a new long Swiss GHD series (1444 to 2011). During the climax of the heat wave in early August the grapes desiccated on the vine, which caused many vine-growers to interrupt or postpone the harvest despite full grape maturity until after the next spell of rain. Likewise, the leaves of many trees withered and fell to the ground under extreme drought stress as would usually be expected in late autumn. It remains to be determined by further research whether and how far this result obtained from local analyses can be spatially extrapolated. Based on the temperature estimates for Switzerland it is assumed from a great number of coherent qualitative documentary evidence about the outstanding heat drought in 1540 that AMJJ temperatures were likely more extreme in neighbouring regions of Western and Central Europe than in 2003. Considering the significance of soil moisture deficits for record breaking heat waves, these results still need to be validated with estimated seasonal precipitation. It is concluded that biological proxy data may not properly reveal record breaking heat and drought events. Such assessments thus need to be complemented with the critical study of contemporary evidence from

  17. Using stable isotopes of carbon to investigate the seasonal variation of carbon transfer in a northwestern Arkansas cave

    Science.gov (United States)

    Knierim, Katherine J.; Pollock, Erik; Hays, Phillip D.; Khojasteh, Jam

    2015-01-01

    Stable-isotope analyses are valuable in karst settings, where characterizing biogeochemical cycling of carbon along groundwater flow paths is critical for understanding and protecting sensitive cave and karst water resources. This study quantified the seasonal changes in concentration and isotopic composition (δ13C) of aqueous and gaseous carbon species—dissolved inorganic carbon (DIC) and gaseous carbon dioxide (CO2)—to characterize sources and transfer of these species along a karst flow path, with emphasis on a cave environment. Gas and water samples were collected from the soil and a cave in northwestern Arkansas approximately once a month for one year to characterize carbon cycling along a conceptual groundwater flow path. In the soil, as the DIC concentration increased, the isotopic composition of the DIC became relatively lighter, indicating an organic carbon source for a component of the DIC and corroborating soil DIC as a proxy for soil respiration. In the cave, a positive correlation between DIC and surface temperature was due to increased soil respiration as the organic carbon signal from the soil was transferred to the cave environment via the aqueous phase. CO2 concentration was lowest in the cave during colder months and increased exponentially with increasing surface temperature, presumably due to higher rates of soil respiration during warmer periods and changing ventilation patterns between the surface and cave atmosphere. Isotopic disequilibrium between CO2 and DIC in the cave was greatest when CO2 concentration was changing during November/ December and March/April, presumably due to the rapid addition or removal of gaseous CO2. The isotopic disequilibrium between DIC and CO2 provided evidence that cave CO2 was a mixture of carbon from several sources, which was mostly constrained by mixture between atmospheric CO2 and soil CO2. The concentration and isotopic composition of gaseous and aqueous carbon species were controlled by month

  18. Higher education

    OpenAIRE

    Wolter, Andrä

    2009-01-01

    During the last five years higher education research in Germany seems to be in a significant upturn. This is a side effect partly of the obvious boom of empirical educational research in general and partly of the reform movement that has affected the German higher education system since middle of the 1990s. The demand for data in the field of higher education will increase considerably in future. The available data infrastructure for higher education research in Germany consists of two comple...

  19. Against the flow: evidence of multiple recent invasions of warmer continental shelf waters by a Southern Ocean brittle star

    Directory of Open Access Journals (Sweden)

    Chester John Sands

    2015-06-01

    Full Text Available The Southern Ocean is anomalously rich in benthos. This biodiversity is native, mostly endemic and perceived to be uniquely threatened from climate- and anthropogenically- mediated invasions. Major international scientific effort throughout the last decade has revealed more connectivity than expected between fauna north and south of the worlds strongest marine barrier – the Polar Front (the strongest jet of the Antarctic Circumpolar Current. To date though, no research has demonstrated any radiations of marine taxa out from the Southern Ocean, except at abyssal depths (where conditions differ much less. Our phylogeographic investigation of one of the most ubiquitous and abundant clades at high southern latitudes, the ophiuroids (brittlestars, shows that one of them, Ophiura lymani, has gone against the flow. Remarkably our genetic data suggest that O. lymani has successfully invaded the South American shelf from Antarctica at least three times, in recent (Pleistocene radiation. Many previous studies have demonstrated links within clades across the PF this is the first in which northwards directional movement of a shelf-restricted species is the only convincing explanation. Rapid, recent, regional warming is likely to facilitate multiple range shift invasions into the Southern Ocean, whereas movement of cold adapted fauna (considered highly stenothermal out of the Antarctic to warmer shelves has, until now, seemed highly unlikely.

  20. Analysis of long-term variation of the annual number of warmer and colder days using Mahalanobis distance metrics - A case study for Athens

    Science.gov (United States)

    Matcharashvili, Teimuraz; Zhukova, Natalia; Chelidze, Tamaz; Founda, Dimitra; Gerasopoulos, Evangelos

    2017-12-01

    According to contemporary observations and analyses an increase in the number of warm days is evident, associated to global warming and the air temperature increase. At the same time, many questions regarding the variation of the yearly number of warm (and cold) day anomalies remain unanswered. In the present work, we used a 99-year long time series of daily maximum air temperatures from the historical, climatic station in Athens, Greece, to produce data sets of sequences of the yearly number of days with anomalies significantly larger (warmer)/lower (colder), with respect to the long-term mean anomalies for the same days. The main goal was to introduce and test the appropriateness of our approach, in assessing changes of the local climate system during last century. This approach is based on the Mahalanobis distance metrics of the variability of the annual number of warmer and colder days derived from the long period data sets of the daily max air temperatures. We show that in Athens the features of the local climate system, assessed by the variability of warmer and colder days, have significantly changed during the observation period. In particular, essential changes are revealed in the temporal correlations of the variability of the annual number of warmer and colder days, during different sub-periods in the past century. Greater changes are found in the last two to three decades, though similar or even stronger changes have also occurred in the past.

  1. Interannual and Seasonal Patterns of Carbon Dioxide, Water, and Energy Fluxes From Ecotonal and Thermokarst-Impacted Ecosystems on Carbon-Rich Permafrost Soils in Northeastern Siberia

    Science.gov (United States)

    Euskirchen, Eugénie S.; Edgar, Colin W.; Syndonia Bret-Harte, M.; Kade, Anja; Zimov, Nikita; Zimov, Sergey

    2017-10-01

    Eastern Siberia Russia is currently experiencing a distinct and unprecedented rate of warming. This change is particularly important given the large amounts of carbon stored in the yedoma permafrost soils that become vulnerable to thaw and release under warming. Data from this region pertaining to year-round carbon, water, and energy fluxes are scarce, particularly in sensitive ecotonal ecosystems near latitudinal treeline, as well as those already impacted by permafrost thaw. Here we investigated the interannual and seasonal carbon dioxide, water, and energy dynamics at an ecotonal forested site and a disturbed thermokarst-impacted site. The ecotonal site was approximately neutral in terms of CO2 uptake/release, while the disturbed site was either a source or neutral. Our data suggest that high rates of plant productivity during the growing season at the disturbed site may, in part, counterbalance higher rates of respiration during the cold season compared to the ecotonal site. We also found that the ecotonal site was sensitive to the timing of the freezeup of the soil active layer in fall, releasing more CO2 when freezeup occurred later. Both sites showed a negative water balance, although the ecotonal site appeared more sensitive to dry conditions. Water use efficiency at the ecotonal site was lower during warmer summers. Overall, these Siberian measurements indicate ecosystem sensitivity to warmer conditions during the fall and to drier conditions during the growing season and provide a better understanding of ecosystem response to climate in a part of the circumpolar Arctic where current knowledge is weakest.

  2. Impacts of diurnal temperature range on ecosystem carbon balance: an experimental test in grassland mesocosms

    Science.gov (United States)

    Phillips, C. L.; Gregg, J. W.; Wilson, J. K.; Pangle, L. A.; Bailey, D.

    2009-12-01

    Although extensive research has determined ecosystem responses to equal increases in day and night temperatures, current temperature increases have generally been asymmetrical, with increases in minimum temperature (Tmin) exceeding increases in maximum temperature (Tmax), or vice versa, depending on location. We conducted an ecosystem warming experiment in a perennial grassland to determine the effects of asymmetrically elevated diel temperature profiles using precision climate-controlled sunlit environmental chambers. Asymmetrically warmed chambers (+5/+2°C, Tmin/Tmax) were compared with symmetrically warmed (+3.5°C continuously) and control chambers (ambient). We tested three alternative hypotheses comparing the carbon balance under symmetric (SYM) and asymmetric (ASYM) warming: H1) SYM ASYM, because warmer nights in the ASYM treatment increase respiration more then photosynthesis, reducing plant growth; H3) SYM = ASYM, due to a combination of effects. Results from the third growing season support H3, that carbon balance is the same under the two elevated diel temperature profiles. During the early part of the growing season, asymmetric warming resulted in higher nighttime respiratory losses than symmetric warming, but these greater loses were compensated by increased early morning photosynthesis. As a result, carbon balance was not different in the two warming treatments at daily time steps. Furthermore, declines in soil moisture over the growing season may have important modulating impacts on the temperature sensitivity of carbon fluxes. As soils dried, carbon fluxes became less sensitive to diel temperature fluctuations, and more similar in the symmetric and asymmetric treatments.

  3. Carbon allocation belowground in Pinus pinaster using stable carbon isotope pulse labeling technique

    Science.gov (United States)

    Dannoura, M.; Bosc, A.; Chipeaux, C.; Sartore, M.; Lambrot, C.; Trichet, P.; Bakker, M.; Loustau, D.; Epron, D.

    2010-12-01

    Carbon allocation belowground competes with aboveground growth and biomass production. In the other hand, it contributes to resource acquisition such as nutrient, water and carbon sequestration in soil. Thus, a better characterization of carbon flow from plant to soil and its residence time within each compartment is an important issue for understanding and modeling forest ecosystem carbon budget. 13C pulse labeling of whole crown was conducted at 4 seasons to study the fate of assimilated carbon by photosynthesis into the root on 12 year old Pinus pinaster planted in the INRA domain of Pierroton. Maritime pine is the most widely planted species in South-West Europe. Stem, root and soil CO2 effluxes and their isotope composition were measured continuously by tunable diode laser absorption spectroscopy with a trace gas analyzer (TGA 100A; Campbell Scientific) coupled to flow-through chambers. 13CO2 recovery and peak were observed in respiration of each compartment after labeling. It appeared sequentially from top of stem to bottom, and to coarse root. The maximum velocity of carbon transfer was calculated as the difference in time lag of recovery between two positions on the trunk or on the root. It ranged between 0.08-0.2 m h-1 in stem and between 0.04-0.12 m h-1 in coarse root. This velocity was higher in warmer season, and the difference between time lag of recovery and peak increased after first frost. Photosynthates arrived underground 1.5 to 5 days after labeling, at similar time in soil CO2 effluxes and coarse root respiration. 0.08-1.4 g of carbon was respired per tree during first 20 days following labeling. It presented 0.6 -10% of 13C used for labeling and it is strongly related to seasons. The isotope signal was detected in fine root organs and microbial biomass by periodical core sampling. The peak was observed 6 days after labeling in early summer while it was delayed more than 10 days in autumn and winter with less amount of carbon allocated

  4. Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera (Ammonia tepida and Haynesina germanica

    Directory of Open Access Journals (Sweden)

    J. Wukovits

    2017-06-01

    Full Text Available Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but future environmental changes will challenge the tolerance limits of intertidal species. Metabolic rates and physiological processes in foraminifera are strongly dependent on environmental temperatures. Temperature-related stress could therefore impact foraminiferal food source processing efficiency and might result in altered nutrient fluxes through the intertidal food web. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus retention. The specimens were fed with 13C and 15N labelled freeze-dried Dunaliella tertiolecta (green algae at the start of the experiment and were incubated at 20, 25 and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of 2 weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on the carbon uptake of H. germanica than on A. tepida. A distinct increase in the levels of phytodetrital-derived nitrogen (compared to more steady carbon levels could be observed over the course of the experiment in both species. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods if the main food source consists of chlorophyte phytodetritus

  5. Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera (Ammonia tepida and Haynesina germanica)

    Science.gov (United States)

    Wukovits, Julia; Enge, Annekatrin Julie; Wanek, Wolfgang; Watzka, Margarete; Heinz, Petra

    2017-06-01

    Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but future environmental changes will challenge the tolerance limits of intertidal species. Metabolic rates and physiological processes in foraminifera are strongly dependent on environmental temperatures. Temperature-related stress could therefore impact foraminiferal food source processing efficiency and might result in altered nutrient fluxes through the intertidal food web. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus retention. The specimens were fed with 13C and 15N labelled freeze-dried Dunaliella tertiolecta (green algae) at the start of the experiment and were incubated at 20, 25 and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of 2 weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on the carbon uptake of H. germanica than on A. tepida. A distinct increase in the levels of phytodetrital-derived nitrogen (compared to more steady carbon levels) could be observed over the course of the experiment in both species. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods if the main food source consists of chlorophyte phytodetritus. These conditions are

  6. Higher Education.

    Science.gov (United States)

    Hendrickson, Robert M.

    This chapter reviews litigation in higher education for 1986. The first section discusses the relationship between postsecondary institutions and various governmental agencies, in which litigation covers questions on the authority of boards, access to information through sunshine laws, questions of tax exempt status, and issues of accreditation.…

  7. Assessing neonatal heat balance and physiological strain in newborn infants nursed under radiant warmers in intensive care with fentanyl sedation.

    Science.gov (United States)

    Molgat-Seon, Yannick; Daboval, Thierry; Chou, Shirley; Jay, Ollie

    2014-12-01

    To assess heat balance status of newborn infants nursed under radiant warmers (RWs) during intensive care. Heat balance, thermal status and primary indicators of physiological strain were concurrently measured in 14 newborns nursed under RWs for 105 min. Metabolic heat production (M), evaporative heat loss (E), convective (C) and conductive heat flow (K), rectal temperature (T re) and mean skin temperatures (T sk) were measured continuously. The rate of radiant heat required for heat balance (R req) and the rate of radiant heat provided (R prov) were derived. The rate of body heat storage (S) was calculated using a two-compartment model of 'core' (T re) and 'shell' (T sk) temperatures. Mean M, E, C and K were 10.5 ± 2.7 W, 5.8 ± 1.1 W, 6.2 ± 0.8 W and 0.1 ± 0.1 W, respectively. Mean R prov (1.7 ± 2.6 W) and R req (1.7 ± 2.7 W) were similar (p > 0.05). However, while the resultant mean change in body heat content after 105 min was negligible (-0.1 ± 3.7 kJ), acute time-dependent changes in S were evidenced by a mean positive heat storage component of +6.4 ± 2.6 kJ and a mean negative heat storage component of -6.5 ± 3.7 kJ. Accordingly, large fluctuations in both T re and T sk occurred that were actively induced by changes in RW output. Nonetheless, no active physiological responses (heart rate, breathing frequency and mean arterial pressure) to these bouts of heating and cooling were observed. RWs maintain net heat balance over a prolonged period, but actively induce acute bouts of heat imbalance that cause rapid changes in T re and T sk. Transient bouts of heat storage do not exacerbate physiological strain, but could in the longer term.

  8. A Global Perspective on Warmer Droughts as a Key Driver of Forest Disturbances and Tree Mortality (Invited)

    Science.gov (United States)

    Allen, C. D.

    2013-12-01

    Recent global warming, in concert with episodic droughts, is causing elevated levels of both chronic and acute forest water stress across large regions. Such increases in water stress affect forest dynamics in multiple ways, including by amplifying the incidence and severity of many significant forest disturbances, particularly drought-induced tree mortality, wildfire, and outbreaks of damaging insects and diseases. Emerging global-scale patterns of drought-related forest die-off are presented, including a newly updated map overview of documented drought- and heat-induced tree mortality events from around the world, demonstrating the vulnerability of all major forest types to forest drought stress, even in typically wet environments. Comparative patterns of drought stress and associated forest disturbances are reviewed for several regions (southwestern Australia, Inner Asia, western North America, Mediterranean Basin), including interactions among climate and various disturbance processes. From the Southwest USA, research is presented that derives a tree-ring-based Forest Drought Stress Index (FDSI) for the most regionally-widespread conifer species (Pinus edulis, Pinus ponderosa, and Pseudotsuga menziesii), demonstrating recent escalation of FDSI to extreme levels relative to the past 1000 years, due to both drought and especially warming. This new work further highlights strong correlations between drought stress and amplified forest disturbances (fire, bark beetle outbreaks), and projects that by CE 2050 anticipated regional warming will cause mean FDSI values to reach historically unprecedented levels that may exceed thresholds for the survival of current tree species in large portions of their current range in the Southwest. Similar patterns of recent climate-amplified forest disturbance risk are apparent from a variety of relatively dry regions across this planet, and given climate projections for substantially warmer temperatures and greater drought stress

  9. Impacts of mitigation strategies in France, via afforestation, on climate in a 1.5°C warmer world

    Science.gov (United States)

    Strada, S.; De Noblet-Ducoudré, N.; Stéfanon, M.

    2016-12-01

    Through land-atmosphere interactions, human-driven land-use and land-cover changes (LULCCs) have unbalanced the Earth System's energy, water and emission fluxes, with consequences on weather, air quality and climate at different scales, from local to global. By altering atmospheric conditions, regional LULCCs may play an important role in the context of climate change. In a warmer and wetter climate, LULCCs may either enhance or dampen climate impacts at the regional scale via the feedbacks LULCCs will initiate, finally affecting the functioning of terrestrial ecosystems and, thereby, mitigation and adaptation strategies. In the aftermath of COP21, scenarios depicting a rise of 1.5°C in the global average temperature, relative to the pre-industrial period, have drawn the attention of stakeholders. As a consequence, the scientific community has been urged to explore impacts of +1.5°C scenarios on the Earth's system. In this framework, we aim to investigate at a regional scale the effects of LULCCs on climate and the resilience of a modified landscape under a +1.5°C climatic scenario. To this purpose, we apply a coupled land-atmosphere regional climate model (WRF-ORCHIDEE) over France to perform sensitivity studies under a pre-industrial and +1.5°C climatic and afforested land-cover scenario. To feed the coupled land-atmosphere model, initial and boundary atmospheric conditions are taken from the global climate model LMDZ output for both pre-industrial (1881‒1910) and +1.5°C period (2009‒2038). To depict pre-industrial and future land-cover in France, we use land-cover data from the last IPCC AR5 report for year 1895 (historical database) and year 2100 from the RCP4.5 scenario, which maximizes the extent of afforestation in France among all RCPs compared to the pre-industrial period. Results are discussed in terms of the impacts of land-atmosphere interactions on mean and extreme atmospheric conditions (e.g., surface temperature, precipitation). This study

  10. Enhanced tortuosity for electrolytes in microwave irradiated self-organized carbon-doped Ni/Co hydroxide nanocomposite electrodes with higher Ni/Co atomic ratio and rate capability for an asymmetric supercapacitor

    Science.gov (United States)

    Kumar, Niraj; Kumar, Viresh; Panda, H. S.

    2017-11-01

    We demonstrate a green, facile and rapid microwave-mediated process for fabricating carbon black (CB) incorporated Ni/Co hydroxide porous nanocomposites and study the effect of various mass loading of CB on supercapacitor performance. The structure and interactions between CB and Ni/Co hydroxide are characterized by using x-ray diffraction, Fourier-transform infrared spectroscopy and x-ray photoelectron spectroscopy, which suggest the miniaturization of the single-phase Ni/Co hydroxide formation time. A morphology study reveals that the addition of CB into Ni/Co hydroxide develops a loose network structure with well-defined architectural pores. In addition, the nanocomposites demonstrate noticeable improvements in porosity and atomic ratio of Ni/Co with an increasing percentage of carbon, which results in a higher diffusion of electrolytes, and hence electrical conduction. The developed electrode materials exhibit a maximum specific capacitance value of 1526 Fg-1 at current density 1 Ag-1 with excellent cyclic stability (92% retention at 5000 cycles), energy density (76 Wh Kg-1), power density (250 W Kg-1) and rate capability. A solid state asymmetric supercapacitor device is fabricated and utilized to brighten a commercial LED effectively for validating real usage.

  11. Climate warming shifts carbon allocation from stemwood to roots in calcium-depleted spruce forests

    Science.gov (United States)

    Lapenis, Andrei Gennady; Lawrence, Gregory B.; Heim, Alexander; Zheng, Chengyang; Shortle, Walter

    2013-01-01

    Increased greening of northern forests, measured by the Normalized Difference Vegetation Index (NDVI), has been presented as evidence that a warmer climate has increased both net primary productivity (NPP) and the carbon sink in boreal forests. However, higher production and greener canopies may accompany changes in carbon allocation that favor foliage or fine roots over less decomposable woody biomass. Furthermore, tree core data throughout mid- and northern latitudes have revealed a divergence problem (DP), a weakening in tree ring responses to warming over the past half century that is receiving increasing attention, but remains poorly understood. Often, the same sites exhibit trend inconsistency phenomenon (TIP), namely positive, or no trends in growing season NDVI where negative trends in tree ring indexes are observed. Here we studied growth of two Norway spruce (Picea abies) stands in western Russia that exhibited both the DP and TIP but were subject to soil acidification and calcium depletion of differing timing and severity. Our results link the decline in radial growth starting in 1980 to a shift in carbon allocation from wood to roots driven by a combination of two factors: (a) soil acidification that depleted calcium and impaired root function and (b) earlier onset of the growing season that further taxed the root system. The latter change in phenology appears to act as a trigger at both sites to push trees into nutrient limitation as the demand for Ca increased with the longer growing season, thereby causing the shift in carbon allocation.

  12. Permafrost collapse shifts alpine tundra to a carbon source but reduces N2O and CH4 release on the northern Qinghai-Tibetan Plateau

    Science.gov (United States)

    Mu, C. C.; Abbott, B. W.; Zhao, Q.; Su, H.; Wang, S. F.; Wu, Q. B.; Zhang, T. J.; Wu, X. D.

    2017-09-01

    Important unknowns remain about how abrupt permafrost collapse (thermokarst) affects carbon balance and greenhouse gas flux, limiting our ability to predict the magnitude and timing of the permafrost carbon feedback. We measured monthly, growing-season fluxes of CO2, CH4, and N2O at a large thermokarst feature in alpine tundra on the northern Qinghai-Tibetan Plateau (QTP). Thermokarst formation disrupted plant growth and soil hydrology, shifting the ecosystem from a growing-season carbon sink to a weak source but decreasing feature level CH4 and N2O flux. Temperature-corrected ecosystem respiration from decomposing permafrost soil was 2.7 to 9.5-fold higher than in similar features from Arctic and Boreal regions, suggesting that warmer and dryer conditions on the northern QTP could accelerate carbon decomposition following permafrost collapse. N2O flux was similar to the highest values reported for Arctic ecosystems and was 60% higher from exposed mineral soil on the feature floor, confirming Arctic observations of coupled nitrification and denitrification in collapsed soils. Q10 values for respiration were typically over 4, suggesting high-temperature sensitivity of thawed carbon. Taken together, these results suggest that QTP permafrost carbon in alpine tundra is highly vulnerable to mineralization following thaw, and that N2O production could be an important noncarbon permafrost climate feedback. Permafrost collapse altered soil hydrology, shifting the ecosystem from a carbon sink to carbon source but decreasing CH4 and N2O flux. Little to no vegetation recovery after stabilization suggests potentially large net carbon losses. High N2O flux compared to Arctic and Boreal systems suggests noncarbon permafrost climate feedback.

  13. Two Step Wittig/Dihydroxylation Synthetic Route to Higher Sugars

    DEFF Research Database (Denmark)

    Jørgensen, Morten; Madsen, Robert

    1999-01-01

    Higher carbon sugars are obtained by a two carbon, two step chain elongation of aldoses involving first a Wittig reaction and then an osmium tetroxide catalyzed dihydroxylation......Higher carbon sugars are obtained by a two carbon, two step chain elongation of aldoses involving first a Wittig reaction and then an osmium tetroxide catalyzed dihydroxylation...

  14. A warmer and drier climate in the northern sagebrush biome does not promote cheatgrass invasion or change its response to fire.

    Science.gov (United States)

    Larson, Christian D; Lehnhoff, Erik A; Rew, Lisa J

    2017-12-01

    Dryland shrub communities have been degraded by a range of disturbances and now face additional stress from global climate change. The spring/summer growing season of the North American sagebrush biome is projected to become warmer and drier, which is expected to facilitate the expansion of the invasive annual grass Bromus tectorum (cheatgrass) and alter its response to fire in the northern extent of the biome. We tested these predictions with a factorial experiment with two levels of burning (spring burn and none) and three climate treatments (warming, warming + drying, and control) that was repeated over 3 years in a Montana sagebrush steppe. We expected the climate treatments to make B. tectorum more competitive with the native perennial grass community, especially Pseudoroegneria spicata, and alter its response to fire. Experimental warming and warming + drying reduced B. tectorum cover, biomass, and fecundity, but there was no response to fire except for fecundity, which increased; the native grass community was the most significant factor that affected B. tectorum metrics. The experimental climate treatments also negatively affected P. spicata, total native grass cover, and community biodiversity, while fire negatively affected total native grass cover, particularly when climate conditions were warmer and drier. Our short-term results indicate that without sufficient antecedent moisture and a significant disruption to the native perennial grass community, a change in climate to a warmer and drier spring/summer growing season in the northern sagebrush biome will not facilitate B. tectorum invasion or alter its response to fire.

  15. Differential responses of production and respiration to temperature and moisture drive the carbon balance across a climatic gradient in New Mexico

    Science.gov (United States)

    Kristina J. Anderson-Teixeira; John P. Delong; Andrew M. Fox; Daniel A. Brese; Marcy E. Litvak

    2011-01-01

    Southwestern North America faces an imminent transition to a warmer, more arid climate, and it is critical to understand how these changes will affect the carbon balance of southwest ecosystems. In order to test our hypothesis that differential responses of production and respiration to temperature and moisture shape the carbon balance across a range of spatio-temporal...

  16. Fuel Class Higher Alcohols

    KAUST Repository

    Sarathy, Mani

    2016-08-17

    This chapter focuses on the production and combustion of alcohol fuels with four or more carbon atoms, which we classify as higher alcohols. It assesses the feasibility of utilizing various C4-C8 alcohols as fuels for internal combustion engines. Utilizing higher-molecular-weight alcohols as fuels requires careful analysis of their fuel properties. ASTM standards provide fuel property requirements for spark-ignition (SI) and compression-ignition (CI) engines such as the stability, lubricity, viscosity, and cold filter plugging point (CFPP) properties of blends of higher alcohols. Important combustion properties that are studied include laminar and turbulent flame speeds, flame blowout/extinction limits, ignition delay under various mixing conditions, and gas-phase and particulate emissions. The chapter focuses on the combustion of higher alcohols in reciprocating SI and CI engines and discusses higher alcohol performance in SI and CI engines. Finally, the chapter identifies the sources, production pathways, and technologies currently being pursued for production of some fuels, including n-butanol, iso-butanol, and n-octanol.

  17. RECONSTRUCTION AND ANALYSIS OF HISTORICAL CHANGES IN CARBON STORAGE IN ARCTIC TUNDRA

    Science.gov (United States)

    Surface air temperature in arctic regions has increased since pre-industrial times, raising concerns that warmer and possibly drier conditions have increased soil decomposition rates, thereby stimulating the release to the atmosphere of the large stores of carbon (C) in arctic so...

  18. Cold acclimation in warmer extended autumns impairs freezing tolerance of perennial ryegrass (Lolium perenne) and timothy (Phleum pratense).

    Science.gov (United States)

    Dalmannsdottir, Sigridur; Jørgensen, Marit; Rapacz, Marcin; Østrem, Liv; Larsen, Arild; Rødven, Rolf; Rognli, Odd Arne

    2017-07-01

    The effect of variable autumn temperatures in combination with decreasing irradiance and daylength on photosynthesis, growth cessation and freezing tolerance was investigated in northern- and southern-adapted populations of perennial ryegrass (Lolium perenne) and timothy (Phleum pratense) intended for use in regions at northern high latitudes. Plants were subjected to three different acclimation temperatures; 12, 6 and 9/3°C (day/night) for 4 weeks, followed by 1 week of cold acclimation at 2°C under natural light conditions. This experimental setup was repeated at three different periods during autumn with decreasing sums of irradiance and daylengths. Photoacclimation, leaf elongation and freezing tolerance were studied. The results showed that plants cold acclimated during the period with lowest irradiance and shortest day had lowest freezing tolerance, lowest photosynthetic activity, longest leaves and least biomass production. Higher acclimation temperature (12°C) resulted in lower freezing tolerance, lower photosynthetic activity, faster leaf elongation rate and higher biomass compared with the other temperatures. Photochemical mechanisms were predominant in photoacclimation. The northern-adapted populations had a better freezing tolerance than the southern-adapted except when grown during the late autumn period and at the highest temperature; then there were no differences between the populations. Our results indicate that the projected climate change in the north may reduce freezing tolerance in grasses as acclimation will take place at higher temperatures and shorter daylengths with lower irradiance. © 2017 Scandinavian Plant Physiology Society.

  19. Trihalomethane, haloacetonitrile, and chloral hydrate formation potentials of organic carbon fractions from sub-tropical forest soils.

    Science.gov (United States)

    Zhang, Qian; Kuang, Wan-fang; Liu, Lu-ying; Li, Kexin; Wong, Kin-hang; Chow, Alex T; Wong, Po-keung

    2009-12-30

    Forest landscapes represent the major land-cover type for the watersheds of the East River, which is the source of water for 40 million people in South China. Forest soils with high levels of organic carbon are a potential terrestrial source of dissolved organic carbon (DOC) into the East River. DOC is of great concern, since it can form carcinogenic disinfection byproducts (DBPs) during drinking water treatment. In this study, soils from three altitudes (200, 450 and 900 m) in the Xiangtou Mountain Nature Reserve in South China, representing soils from evergreen moon forest, transitional evergreen broadleaf forest, and evergreen broadleaf forest, respectively, were evaluated for their potential contributions of DBP precursors into the East River. The water extractable organic carbon (WEOC) in three forest soils was physically and chemically fractionated into particulate organic carbon (1.2-0.45 microm), colloidal organic carbon (0.45-0.22 microm), and dissolved organic carbon (DOC) (impact of temperature effects on the availability and characteristics of WEOC. The extraction study showed that the amount of WEOC was proportional to soil organic carbon content, of which about 1% was water extractable. Regardless of soil type, DOC and HPOA were the most reactive fractions in forming THMs, CHD, and HANs. Production of DOC and HPOA in WEOC increased over 14 d incubation as incubation temperature increased, but the temperature did not alter the distribution of physical and chemical fractions and their reactivity in DBP formation. Results suggest higher inputs of DOC and DBP precursors from forest watersheds into source water may result in a warmer environment.

  20. Effects of a future warmer ocean on the coexisting copepods Calanus finmarchicus and C. glacialis in Disko Bay, Western Greenland

    DEFF Research Database (Denmark)

    Kjellerup, Sanne; Dünweber, Michael; Swalethorp, Rasmus

    2012-01-01

    egg production at temperatures between 0 and 2.5°C. Higher temperatures did not increase egg production considerably, whereas egg production for C. finmarchicus more than tripled between 2.5 and 5°C. Starved C. glacialis produced eggs at all temperatures stimulated by increasing temperatures, whereas...... starved C. finmarchicus needed temperatures above 5°C to produce eggs fueled by their lipid stores. Few C. finmarchicus had mature gonads at the initiation of the pre-bloom and bloom experiment, and egg production of C. finmarchicus therefore only increased as the ratio of individuals with mature gonads...

  1. Stability of hemostatic proteins in canine fresh-frozen plasma thawed with a modified commercial microwave warmer or warm water bath.

    Science.gov (United States)

    Pashmakova, Medora B; Barr, James W; Bishop, Micah A

    2015-05-01

    To compare stability of hemostatic proteins in canine fresh-frozen plasma (FFP) thawed with a modified commercial microwave warmer (MCM) or warm water bath (37°C; WWB) or at room temperature (22°C). Fresh-frozen plasma obtained from 8 canine donors of a commercial blood bank. A commercial microwave warmer was modified with a thermocouple to measure surface temperature of bags containing plasma. The MCM and a WWB were each used to concurrently thaw a 60-mL bag of plasma obtained from the same donor. Two 3-mL control aliquots of FFP from each donor were thawed to room temperature without use of a heating device. Concentrations of hemostatic proteins, albumin, and D-dimers; prothrombin time (PT); and activated partial thromboplastin time (aPTT) were determined for all samples. Significant decreases in concentrations of factors II, IX, X, XI, fibrinogen, von Willebrand factor, antithrombin, protein C, and albumin and significant increases in PT and aPTT were detected for plasma thawed with the MCM, compared with results for samples thawed with the WWB. Concentrations of factors VII, VIII, and XII were not significantly different between plasma thawed with the MCM and WWB. Concentrations of D-dimers were above the reference range for all thawed samples regardless of thawing method. No significant differences in factor concentrations were detected between control and WWB-thawed samples. Significant differences in hemostatic protein concentrations and coagulation times were detected for plasma thawed with an MCM but not between control and WWB-thawed samples. Clinical importance of these changes should be investigated.

  2. The warmer the weather, the more gram-negative bacteria - impact of temperature on clinical isolates in intensive care units.

    Science.gov (United States)

    Schwab, Frank; Gastmeier, Petra; Meyer, Elisabeth

    2014-01-01

    We investigated the relationship between average monthly temperature and the most common clinical pathogens causing infections in intensive care patients. A prospective unit-based study in 73 German intensive care units located in 41 different hospitals and 31 different cities with total 188,949 pathogen isolates (102,377 Gram-positives and 86,572 Gram-negatives) from 2001 to 2012. We estimated the relationship between the number of clinical pathogens per month and the average temperature in the month of isolation and in the month prior to isolation while adjusting for confounders and long-term trends using time series analysis. Adjusted incidence rate ratios for temperature parameters were estimated based on generalized estimating equation models which account for clustering effects. The incidence density of Gram-negative pathogens was 15% (IRR 1.15, 95%CI 1.10-1.21) higher at temperatures ≥ 20°C than at temperatures below 5°C. E. cloacae occurred 43% (IRR=1.43; 95%CI 1.31-1.56) more frequently at high temperatures, A. baumannii 37% (IRR=1.37; 95%CI 1.11-1.69), S. maltophilia 32% (IRR=1.32; 95%CI 1.12-1.57), K. pneumoniae 26% (IRR=1.26; 95%CI 1.13-1.39), Citrobacter spp. 19% (IRR=1.19; 95%CI 0.99-1.44) and coagulase-negative staphylococci 13% (IRR=1.13; 95%CI 1.04-1.22). By contrast, S. pneumoniae 35% (IRR=0.65; 95%CI 0.50-0.84) less frequently isolated at high temperatures. For each 5°C increase, we observed a 3% (IRR=1.03; 95%CI 1.02-1.04) increase of Gram-negative pathogens. This increase was highest for A. baumannii with 8% (IRR=1.08; 95%CI 1.05-1.12) followed by K. pneumoniae, Citrobacter spp. and E. cloacae with 7%. Clinical pathogens vary by incidence density with temperature. Significant higher incidence densities of Gram-negative pathogens were observed during summer whereas S. pneumoniae peaked in winter. There is increasing evidence that different seasonality due to physiologic changes underlies host susceptibility to different bacterial pathogens

  3. The warmer the weather, the more gram-negative bacteria - impact of temperature on clinical isolates in intensive care units.

    Directory of Open Access Journals (Sweden)

    Frank Schwab

    Full Text Available BACKGROUND: We investigated the relationship between average monthly temperature and the most common clinical pathogens causing infections in intensive care patients. METHODS: A prospective unit-based study in 73 German intensive care units located in 41 different hospitals and 31 different cities with total 188,949 pathogen isolates (102,377 Gram-positives and 86,572 Gram-negatives from 2001 to 2012. We estimated the relationship between the number of clinical pathogens per month and the average temperature in the month of isolation and in the month prior to isolation while adjusting for confounders and long-term trends using time series analysis. Adjusted incidence rate ratios for temperature parameters were estimated based on generalized estimating equation models which account for clustering effects. RESULTS: The incidence density of Gram-negative pathogens was 15% (IRR 1.15, 95%CI 1.10-1.21 higher at temperatures ≥ 20°C than at temperatures below 5°C. E. cloacae occurred 43% (IRR=1.43; 95%CI 1.31-1.56 more frequently at high temperatures, A. baumannii 37% (IRR=1.37; 95%CI 1.11-1.69, S. maltophilia 32% (IRR=1.32; 95%CI 1.12-1.57, K. pneumoniae 26% (IRR=1.26; 95%CI 1.13-1.39, Citrobacter spp. 19% (IRR=1.19; 95%CI 0.99-1.44 and coagulase-negative staphylococci 13% (IRR=1.13; 95%CI 1.04-1.22. By contrast, S. pneumoniae 35% (IRR=0.65; 95%CI 0.50-0.84 less frequently isolated at high temperatures. For each 5°C increase, we observed a 3% (IRR=1.03; 95%CI 1.02-1.04 increase of Gram-negative pathogens. This increase was highest for A. baumannii with 8% (IRR=1.08; 95%CI 1.05-1.12 followed by K. pneumoniae, Citrobacter spp. and E. cloacae with 7%. CONCLUSION: Clinical pathogens vary by incidence density with temperature. Significant higher incidence densities of Gram-negative pathogens were observed during summer whereas S. pneumoniae peaked in winter. There is increasing evidence that different seasonality due to physiologic changes underlies

  4. Projected drought risk in 1.5°C and 2°C warmer climates

    Science.gov (United States)

    Lehner, Flavio; Coats, Sloan; Stocker, Thomas F.; Pendergrass, Angeline G.; Sanderson, Benjamin M.; Raible, Christoph C.; Smerdon, Jason E.

    2017-07-01

    The large socioeconomic costs of droughts make them a crucial target for impact assessments of climate change scenarios. Using multiple drought metrics and a set of simulations with the Community Earth System Model targeting 1.5°C and 2°C above preindustrial global mean temperatures, we investigate changes in aridity and the risk of consecutive drought years. If warming is limited to 2°C, these simulations suggest little change in drought risk for the U.S. Southwest and Central Plains compared to present day. In the Mediterranean and central Europe, however, drought risk increases significantly for both 1.5°C and 2°C warming targets, and the additional 0.5°C of the 2°C climate leads to significantly higher drought risk. Our study suggests that limiting anthropogenic warming to 1.5°C rather than 2°C, as aspired to by the Paris Climate Agreement, may have benefits for future drought risk but that such benefits may be regional and in some cases highly uncertain.

  5. The Carbon Crisis in 90 Seconds

    Science.gov (United States)

    Griffith, Peter

    2011-01-01

    This is a banana; and this is a chunk of coal. The banana is sweet and delicious and fun to eat... the coal is ... none of those things. But they are much more alike than they seem. Both were made by plants and store energy from the sun and carbon gas from the air around us. When you eat the banana, you use the energy stored in the banana to run and jump; and you release carbon gas back into the air around you. Now, carbon in the banana is young fast carbon: just weeks ago the banana was carbon gas in the air, and hours after you eat it, you breathe out the same carbon back into the air. When we burn coal in power plants, we use the energy stored in the coal to generate electricity that powers our homes and factories; and we release carbon gas back into the air around us. But, the carbon in the coal is old slow carbon. Plants took the coal carbon out of the air hundreds of millions of years ago. That carbon has been locked up ever since, and would stay locked up, if people hadn't dug up the coal and burned it. So now by burning coal and oil, people are adding lots and lots of old carbon to the atmosphere, faster than plants and the oceans can take it out. Why do I care? Because carbon gas in the atmosphere acts like a blanket, trapping heat, and making the whole planet warmer. My name is Peter, and I'm a carbon cycle scientist at NASA. We use satellites to watch how the world is warming. We can see the glaciers and the ice caps melting; and the air, land, and oceans warming. So we know we all have to change the way we produce and use energy, to burn less coal and oil, to prevent the planet from getting too warm.

  6. Carbon Dioxide and Methane Emissions from Diverse Zones of a California Salt Marsh

    Science.gov (United States)

    Wang, F.; King, J. Y.

    2016-12-01

    With high primary productivity and low organic matter decomposition rates, salt marshes sequester carbon from the atmosphere and contribute to mitigation of climate change. However, the role of wetlands in carbon sequestration is offset by CO2 and CH4 emissions whose magnitudes remain coarsely constrained. To better understand the spatiotemporal dynamics of gaseous carbon fluxes from marsh soils in a Mediterranean climate, we collected air and soil samples over the course of 10 months at Carpinteria Salt Marsh Reserve (CSMR) located in the County of Santa Barbara, California. The CSMR consists of four distinct zones characterized by differences in elevation, tidal regime, and vegetation. Twelve static chambers were deployed among two lower marsh zones, a salt flat, and a marsh-upland transition zone for fortnightly flux measurements from September, 2015 to May, 2016. In August, 2015 and June, 2016, soil cores up to 50 cm deep were extracted near the chambers, segmented by depth, and analyzed for soil moisture, bulk density, EC, pH, organic/inorganic carbon, and total nitrogen content. The gaseous carbon fluxes showed significant spatiotemporal variability, and soil properties differed noticeably by zone and by depth. Integrated over the study period, the marsh-upland transition zone had the highest CO2 fluxes at 292 g C/m2, followed closely by the lower marsh zones (271 g C/m2 and 189 g C/m2), which were one order of magnitude higher than the CO2 fluxes from the salt flat (23 g C/m2). Seasonally, CO2 fluxes were 2.5 to 3.5 times higher during the warmer months (Sept - Oct, Mar - May) than the colder months (Nov - Feb) across all zones. The CH4 fluxes were more temporally heterogeneous, but overall the CH4 emissions from the lower marsh zones (1.37 g C/m2 and 0.41 g C/m2) surpassed those from the salt flat (0.054 g C/m2) by an order of magnitude, and the marsh-upland transition zone was a net methane sink (-0.029 g C/m2). Our results show that soil gaseous carbon

  7. Fire-induced Carbon Emissions and Regrowth Uptake in Western U.S. Forests: Documenting Variation Across Forest Types, Fire Severity, and Climate Regions

    Science.gov (United States)

    Ghimire, Bardan; Williams, Christopher A.; Collatz, George James; Vanderhoof, Melanie

    2012-01-01

    The forest area in the western United States that burns annually is increasing with warmer temperatures, more frequent droughts, and higher fuel densities. Studies that examine fire effects for regional carbon balances have tended to either focus on individual fires as examples or adopt generalizations without considering how forest type, fire severity, and regional climate influence carbon legacies. This study provides a more detailed characterization of fire effects and quantifies the full carbon impacts in relation to direct emissions, slow release of fire-killed biomass, and net carbon uptake from forest regrowth. We find important variations in fire-induced mortality and combustion across carbon pools (leaf, live wood, dead wood, litter, and duff) and across low- to high-severity classes. This corresponds to fire-induced direct emissions from 1984 to 2008 averaging 4 TgC/yr and biomass killed averaging 10.5 TgC/yr, with average burn area of 2723 sq km/yr across the western United States. These direct emission and biomass killed rates were 1.4 and 3.7 times higher, respectively, for high-severity fires than those for low-severity fires. The results show that forest regrowth varies greatly by forest type and with severity and that these factors impose a sustained carbon uptake legacy. The western U.S. fires between 1984 and 2008 imposed a net source of 12.3 TgC/yr in 2008, accounting for both direct fire emissions (9.5 TgC/yr) and heterotrophic decomposition of fire-killed biomass (6.1 TgC yr1) as well as contemporary regrowth sinks (3.3 TgC/yr). A sizeable trend exists toward increasing emissions as a larger area burns annually.

  8. Food Safety for Warmer Weather

    Science.gov (United States)

    ... certain foods if not stored properly. Bacteria like Staph and Bacillus cereus can make you sick quickly, ... in foods (such as meat or dairy for Staph, and starchy foods like rice for B. cereus ). ...

  9. Warmer amps for the LHC

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    CERN is working together with an Italian company to develop superconducting cables that can function at temperatures of up to 25 K (-248°C). This will make it possible to move LHC magnet power supplies out of the tunnel, protecting them from exposure to the showers of very high-energy particles produced by the accelerator.   Figure 1: devices of this type, which measure approximately 10 metres in length, are inserted between the accelerating magnets at different points along the LHC. When it comes to consuming electricity, the magnets that steer particles through large accelerators can be characterised with just one word: greedy. For the LHC, the total current can reach 1.5 million amps. At the present time, this current is brought in via copper cables of up to 10 cm in diameter. In the tunnel, these cables connect the current leads - which provide the transition between the ambient-temperature cables and the magnets in their bath of superfluid helium - to the power supply. In the a...

  10. Subtropical Low Cloud Response to a Warmer Climate in an Superparameterized Climate Model. Part II: Column Modeling with a Cloud Resolving Model

    Directory of Open Access Journals (Sweden)

    Matthew C Wyant

    2009-07-01

    Full Text Available A cloud resolving model (CRM is used to investigate the low-cloud increase due to a 2 K SST increase in the SP-CAM superparameterized climate model. Of particular interest is the sensitivity of cloud changes to the CRM resolution (4 km horizontal, 30 vertical levels in SP-CAM. The CRM is run in column-modeling framework using SP-CAM composite cloud regimes. The experiments are run to steady state using composite advective tendencies, winds, and sea-surface temperature from the control and +2 K climates of SP-CAM. A new weak temperature gradient algorithm based on an idealized form of gravity wave adjustment is used to adjust vertical motion in the column to keep the simulated virtual temperature profile consistent with the corresponding SP-CAM composite profile. Humidity is also slowly relaxed toward the SP-CAM composite above the boundary layer. With SP-CAM grid resolution, the CRM shows +2 K low cloud increases similar to SP-CAM. With fine grid resolution, the CRM-simulated low cloud fraction and its increase in a warmer climate are much smaller. Hence, the negative low cloud feedbacks in SP-CAM may be exaggerated by under-resolution of trade cumulus boundary layers.

  11. The Svalbard climate transformed rapidly from Younger Dryas climate to warmer-than-present by 11.0 cal ka BP

    Science.gov (United States)

    Mangerud, Jan; Svendsen, John Inge

    2017-04-01

    A compilation of about 130 radiocarbon ages shows early Holocene ages from four species of "warm-water" molluscs that later became extinct from Svalbard (77-80 °N) due to colder climate. These species survived the Younger Dryas south of Scotland, possibly even south of England. Mytilus edulis (blue mussel) arrived Svalbard already at 11.0 cal ka and by 10.6 ka it inhabited the north coast, showing that the Arctic sea-ice limit was far north of the last year's northern records. In 2004 this species reappeared on the west coast of Spitsbergen in response to the ongoing warming of the Arctic. We present for the first time dates of Zirfaea crispata, the most warmth-demanding of the molluscs that lived in this Arctic region. At present Zirfaea has its northern limit near the city of Tromsø, some 1000 km farther south. The six ages that were obtained from Zirfaea shells range from 10.2 to 9.7 cal ka BP, indicating a climate 7 °C warmer than at present and an early Thermal Optimum. Svalbard is presently the warmest place on Earth at such high latitude, caused by northwards Atlantic Ocean currents and large-scale atmospheric circulation. Intensification of these processes and stronger high-latitude insolation were the major drivers of the Thermal Optimum.

  12. Can We Avoid the Permafrost Carbon Tipping Point?

    Science.gov (United States)

    Schaefer, K. M.; Zhang, T.; Bruhwiler, L.; Barrett, A. P.; Li, Z.

    2011-12-01

    If we reduce fossil fuel emissions and slow the Arctic warming rate, can we delay or even avoid the permafrost carbon tipping point? Permafrost currently contains about 1466 Gt of carbon frozen during or since the last ice age. The permafrost carbon tipping point occurs when the release of carbon from thawing permafrost overpowers enhanced uptake due to warmer temperatures. The tipping point indicates when the Arctic irreversibly changes from a carbon sink to a source relative to the atmosphere and marks the start of the Permafrost Carbon Feedback. The tipping point is irreversible because once the carbon thaws and decays into the atmosphere, there is no way to put the carbon back into the permafrost. Projections based on the A1B IPCC scenario indicate that the PCF tipping point will occur between 2020 and 2030, with a total of 190±64 Gt of carbon released into the atmosphere by 2300. We ran a series of model projections out to 2300 based on the A1B scenario, but capped emissions at various levels, each representing a different overall Arctic warming. We present the area of permafrost lost, the permafrost carbon tipping point, and total permafrost carbon flux as a function of Arctic temperature increase. We show the maximum allowed Arctic temperature increase before initiating the permafrost carbon feedback.

  13. Production of biomass, polysaccharides, and ganoderic acid using non-conventional carbon sources under submerged culture of the Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W.Curt.:Fr.)P. Karst. (higher Basidiomycetes).

    Science.gov (United States)

    Zapata, Paola; Rojas, Diego; Atehortúa, Lucía

    2012-01-01

    The effect of different non-conventional carbon sources was studied in the submerged culture of Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum, for simultaneous production of mycelial biomass, bioactive ganoderic acid, and polysaccharides, in less time, using non-conventional carbon sources to minimize the high costs of current culture media. The optimal medium composition was defined as (g/L): 50 of barley flour, 0.2 of KH2PO4, 0.1 of MgSO4ⁱ7H2O, and 1 NH4Cl. Cultivated under this complex culture medium, the mycelial biomass production was 23.49 ± 0.37 g/L; the extracellular polysaccharides production was 2.72 ± 0.11 g/L; the intracellular polysaccharides production was 2.22 ± 0.06 g/L; the ganoderic acids production was 299.67 ± 11.63 mg/L. One liter of culture medium developed in this project was priced at USD $ 0.11 if barley flour is used as carbon source or $ 0.13 with oat flour in order to get a good amount of products of interest.

  14. Temperature-dependent remineralization of organic matter - small impacts on the carbon cycle

    Science.gov (United States)

    Laufkötter, Charlotte; John, Jasmin; Stock, Charles; Dunne, John

    2017-04-01

    The temperature dependence of remineralization of organic matter is regularly mentioned as important but unconstrained factor, with the potential to cause considerable uncertainty in projections of marine export production, carbon sequestration and oceanic carbon uptake. We have recently presented evidence for a temperature dependence of the particulate organic matter (POC) flux to depth, based on a compilation of observations. Here, we explore the impacts of the new temperature dependence on net primary production, POC flux and oceanic carbon uptake in the ecosystem model COBALT coupled to GFDL's ESM2M Coupled Climate-Carbon Earth System Model. We have implemented two remineralization schemes: COBALT-R1 includes a temperature dependence using parameter values according to our data analysis. COBALT-R1 shows very high remineralization in warm surface waters. The data used to constrain it, however, comes from colder water below 150m. Colonization of sinking material occurs throughout the euphotic zone, potentially reducing remineralization in the immediate vicinity of the ocean surface relative to R1 rates [Mislan et al., 2014]. We thus considered a second model version (COBALT-R2) that decreases remineralization towards the surface but ramped up remineralization rates to R1 values below 150m. After 1300 years of spin-up, the effects of the temperature dependence are most visible in the intermediate part of the water column (150 - 1500m), with stronger remineralization in the warmer upper water but weaker remineralization below, such that the carbon flux at 2000m is barely affected. Also, both COBALT-R1 and COBALT-R2 simulate lower POC flux in the low latitudes and higher POC flux in high latitudes compared to the original model version. In terms of future changes, COBALT-R1 projects an increase in NPP while COBALT-R2 projects a moderate decrease. However, the percentaged decrease in POC flux at 100m is identical in both model versions and the original COBALT

  15. Radiocarbon age-offsets in an arctic lake reveal the long-term response of permafrost carbon to climate change

    Science.gov (United States)

    Gaglioti, Benjamin V.; Mann, Daniel H.; Jones, Benjamin M.; Pohlman, John W.; Kunz, Michael L.; Wooller, Matthew J.

    2014-01-01

    Continued warming of the Arctic may cause permafrost to thaw and speed the decomposition of large stores of soil organic carbon (OC), thereby accentuating global warming. However, it is unclear if recent warming has raised the current rates of permafrost OC release to anomalous levels or to what extent soil carbon release is sensitive to climate forcing. Here we use a time series of radiocarbon age-offsets (14C) between the bulk lake sediment and plant macrofossils deposited in an arctic lake as an archive for soil and permafrost OC release over the last 14,500 years. The lake traps and archives OC imported from the watershed and allows us to test whether prior warming events stimulated old carbon release and heightened age-offsets. Today, the age-offset (2 ka; thousand of calibrated years before A.D. 1950) and the depositional rate of ancient OC from the watershed into the lake are relatively low and similar to those during the Younger Dryas cold interval (occurring 12.9–11.7 ka). In contrast, age-offsets were higher (3.0–5.0 ka) when summer air temperatures were warmer than present during the Holocene Thermal Maximum (11.7–9.0 ka) and Bølling-Allerød periods (14.5–12.9 ka). During these warm times, permafrost thaw contributed to ancient OC depositional rates that were ~10 times greater than today. Although permafrost OC was vulnerable to climate warming in the past, we suggest surface soil organic horizons and peat are presently limiting summer thaw and carbon release. As a result, the temperature threshold to trigger widespread permafrost OC release is higher than during previous warming events.

  16. Hydropower's Biogenic Carbon Footprint

    National Research Council Canada - National Science Library

    Scherer, Laura; Pfister, Stephan

    2016-01-01

    .... Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2...

  17. The acute thermal respiratory response is unique among species in a guild of larval anuran amphibians-Implications for energy economy in a warmer future.

    Science.gov (United States)

    Rowe, Christopher L; Crandall, Erin A

    2018-03-15

    Climate change is bringing about increased temperatures of amphibian habitats throughout the world, where ectothermic larvae will experience elevated respiratory (metabolic) energy demands. We compared the acute, thermal respiratory response ("TRR") of four species of sympatric larval amphibians (Lithobates sphenocephalus, L. catesbeianus, Scaphiopus holbrookii, and Hyla chrysoscelis) to determine species-specific differences in the rate at which metabolic energy requirements increase with temperature. The TRR, the slope of the relationship between respiration rate and temperature within critical thermal limits, varied significantly among species such that the absolute, per capita change in metabolic energy requirement as temperature increased was greater for L. sphenocephalus and L. catesbeianus than for H. chrysoscelis and S. holbrookii. This was also reflected in the temperature coefficients (Q10,18.5-25.5), which ranged from 1.77 (S. holbrookii) to 2.70 (L. sphenocephalus) for per capita respiration rates. Our results suggest that L. sphenocephalus and L. catesbeianus will experience a more rapid increase in energetic requirements as temperature increases relative to the other species, possibly magnifying their influences on the resource pool. There is a critical paucity of information on the metabolic responses of most larval amphibians across a range of temperatures, despite that this relationship dictates the magnitude of the priority investment of assimilated energy in respiration, thus shaping the energetic economy of the individual. A broader knowledge of species-specific TRRs, combined with research to determine thermal acclimatory or adaptive potentials over chronic time scales, will provide a framework for evaluating whether asymmetric, climate-mediated differences in energetic demands among species could ultimately influence larval amphibian ecology in a warmer future. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Factors Affecting the Propensity of Tsetse Flies to Enter Houses and Attack Humans Inside: Increased Risk of Sleeping Sickness in Warmer Climates

    Science.gov (United States)

    Vale, Glyn A.; Hargrove, John W.; Chamisa, Andrew; Hall, David R.; Mangwiro, Clement; Torr, Stephen J.

    2013-01-01

    Background Sleeping sickness, or human African trypanosomiasis, is caused by two species of Trypanosoma brucei that are transmitted to humans by tsetse flies (Glossina spp.) when these insects take a bloodmeal. It is commonly assumed that humans must enter the normal woodland habitat of the flies to become infected, but recent studies found that tsetse frequently attack humans inside buildings. Factors affecting human/tsetse contact in buildings need identification. Methodology/Principal Findings In Zimbabwe, tsetse were allowed access to a house via an open door. Those in the house at sunset, and those alighting on humans in the house during the day, were caught using hand-nets. Total catches were unaffected by: (i) the presence of humans in the house and at the door, (ii) wood smoke from a fire inside the house or just outside, (iii) open windows, and (iv) chemicals simulating the odor of cattle or of humans. Catches increased about 10-fold with rising ambient temperatures, and during the hottest months the proportion of the total catch that was taken from the humans increased from 5% to 13%. Of the tsetse caught from humans, 62% consisted of female G. morsitans morstans and both sexes of G. pallidipes, i.e., the group of tsetse that normally alight little on humans. Some of the tsetse caught were old enough to be effective vectors. Conclusion/Significance Present results confirm previous suggestions that buildings provide a distinctive and important venue for transmission of sleeping sickness, especially since the normal repellence of humans and smoke seems poorly effective in such places. The importance of the venue would be increased in warmer climates. PMID:23638209

  19. Physicochemical and Biological Controls on Carbon and Nitrogen in Permafrost from an Ultraxerous Environment, McMurdo Dry Valleys of Antarctica

    Science.gov (United States)

    Faucher, Benoit; Lacelle, Denis; Davila, Alfonso; Pollard, Wayne; Fisher, David; McKay, Christopher P.

    2017-10-01

    Little is known about the abundance and source of soil organic carbon and biogeochemical cycling in permafrost soils from the ultraxerous environment of the Dry Valleys of Antarctica. Here we investigate the distribution, source and cycling of organic carbon, total nitrogen and carbonates in the icy permafrost soils of University Valley, Quartermain Mountains. Results indicate that organic carbon content is lowest in icy soils from the perennially cryotic zone (<40 μg g-1 dry soils) and higher in the icy soils from the seasonally noncryotic zone, where the highest concentrations were found in the warmer-wetter section of the valley and near a frozen pond (up to 313 μg g-1 dry soils). The δ13Corg of organic carbon in the icy soils showed that it is derived from the weathering of Beacon Supergroup sandstone that hosts active endolithic communities. The C:N ratios in icy soils formed two populations: one with ratios <5 and the other with ratios near the Redfield ratios. The low C:N ratios suggest that physicochemical processes dominates these soils, as supported by the absence of microbial activity and atmospherically deposited NO3 with minimal postdeposition modification. The near Redfield C:N ratios can be explained by physical processes (translocation of SOC in the soils from snow meltwater) or balanced microbial activity. The latter is supported by the δ13CCaCO3 values of carbonates that suggest a contribution from microbially respired endolith-derived organic matter, providing indirect evidence of heterotrophic activity in permafrost soils from an ultraxerous environment.

  20. 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.

  1. The carbon fertilization effect over a century of anthropogenic CO2 emissions: higher intracellular CO2 and more drought resistance among invasive and native grass species contrasts with increased water use efficiency for woody plants in the US Southwest.

    Science.gov (United States)

    Drake, Brandon L; Hanson, David T; Lowrey, Timothy K; Sharp, Zachary D

    2017-02-01

    From 1890 to 2015, anthropogenic carbon dioxide emissions have increased atmospheric CO2 concentrations from 270 to 400 mol mol(-1) . The effect of increased carbon emissions on plant growth and reproduction has been the subject of study of free-air CO2 enrichment (FACE) experiments. These experiments have found (i) an increase in internal CO2 partial pressure (ci ) alongside acclimation of photosynthetic capacity, (ii) variable decreases in stomatal conductance, and (iii) that increases in yield do not increase commensurate with CO2 concentrations. Our data set, which includes a 115-year-long selection of grasses collected in New Mexico since 1892, is consistent with an increased ci as a response to historical CO2 increase in the atmosphere, with invasive species showing the largest increase. Comparison with Palmer Drought Sensitivity Index (PDSI) for New Mexico indicates a moderate correlation with Δ(13) C (r(2)  = 0.32, P CO2 in the event of reduced stomatal conductance in response to short-term water shortage. Comparison with C3 trees from arid environments (Pinus longaeva and Pinus edulis in the US Southwest) as well as from wetter environments (Bromus and Poa grasses in New Mexico) suggests differing responses based on environment; arid environments in New Mexico see increased intrinsic water use efficiency (WUE) in response to historic elevated CO2 while wetter environments see increased ci . This study suggests that (i) the observed increases in ci in FACE experiments are consistent with historical CO2 increases and (ii) the CO2 increase influences plant sensitivity to water shortage, through either increased WUE or ci in arid and wet environments, respectively. © 2016 John Wiley & Sons Ltd.

  2. Methanotrophy in London, UK, Landfill Topsoil: Microbiology, Stable Carbon Isotopes, Seasonal Variation and Laboratory Model Study

    Science.gov (United States)

    Sriskantharajah, S.; Fisher, R.; Lowry, D.; Grassineau, N.; Nisbet, E. G.

    2004-12-01

    Landfill is a major source of methane emissions into the atmosphere. Aerobic soil is also a good sink of methane, as it is inhabited by methane consuming bacteria, methanotrophs. Methanotrophic bacteria were cultured from landfill soil samples. Three genera of methanotrophs were cultured: Methylocaldum, Methylosinus and Methylomonas. Interestingly, the only established members of the Methylocaldum genus are all thermophilic, whilst those isolated in this study are mesophilic. This suggests that those Methylocaldum methanotrophs found in landfills may have migrated from hot spring natural settings. Representatives of each genera were inoculated into a simple topsoil model and subjected to variations in temperature, methane concentration and incubation periods. As expected, temperature greatly affected methane oxidation, but methane concentration affected the rate of oxidation far more than expected. The model study implies that the complete combustion of methane to carbon dioxide is greatly affected by temperature and methane availability, whilst the effect on the uptake of methane is not as great. Seasonal variations in methane concentrations within the topsoil were monitored over a one year period from November 2002 to October 2003 and show that methane flow through the topsoil, and consequently methanotrophy, is strongly controlled by meteorology, mainly air temperature and pressure. Generally, methanotrophy was low during colder months and higher at during warmer months, but changes in air pressure complicate this by controlling the rate of flow of methane through the topsoil. δ 13C analyses of methane and carbon dioxide emitted from landfill topsoil showed that there was a great deal of methanotrophic activity during the warmer months of 2003, with most fractionation of residual methane occurring during August. During the heat wave experienced in the UK in August 2003, the δ 13C from borehole samples of methane in the anaerobic zone shifted from -57‰ to -16

  3. Vegetation type and age drive changes in soil properties, nitrogen and carbon sequestration in urban parks under cold climate

    Directory of Open Access Journals (Sweden)

    Heikki Martti Setälä

    2016-08-01

    Full Text Available Urban green spaces provide ecosystem properties fundamental to the provision of ecosystem services, such as the sequestration of carbon and nutrients and serving as a reservoir for organic matter. Although urban vegetation influences soil physico-chemical properties, it remains unknown whether ecosystem properties depend on plant species portfolios. We tested the influence of three common functional plant groups (evergreen trees, deciduous trees, grass/lawn for their ability to modify soils in parks of various ages under cold climatic conditions in Finland. We hypothesized that (i plant functional groups affect soils differently resulting in divergent ecosystem properties, and (ii that these ecosystem properties also depend on park age. We included 41 urban parks of varying ages (10, 50 and > 100 years and additional control forests. Park soils were sampled for physico-chemical parameters up to 50 cm depth. Our data indicate that plant functional groups modify soils differently, especially between the evergreen and lawn treatments at 50 and > 100 year old parks. Soils under evergreen trees had the lowest pH and generally the highest percentage organic matter, percentage total carbon and percentage total nitrogen. Soil pH remained the same, whereas concentrations of organic matter, total carbon and total nitrogen declined by depth. Soils in the reference forests had lower pH but higher percentages organic matter, total carbon and total nitrogen than those in parks. We estimate that old parks with evergreen trees can store 35.5 kg C m-2 and 2.3 kg N m-2 – considerably more than in urban soils in warmer climates. Our data suggest that plant-soil interactions in urban parks, in spite of being constructed environments, are surprisingly similar to those in natural forests.

  4. Net carbon exchange across the Arctic tundra-boreal forest transition in Alaska 1981-2000

    Science.gov (United States)

    Thompson, Catharine Copass; McGuire, A.D.; Clein, Joy S.; Chapin, F. S.; Beringer, J.

    2006-01-01

    Shifts in the carbon balance of high-latitude ecosystems could result from differential responses of vegetation and soil processes to changing moisture and temperature regimes and to a lengthening of the growing season. Although shrub expansion and northward movement of treeline should increase carbon inputs, the effects of these vegetation changes on net carbon exchange have not been evaluated. We selected low shrub, tall shrub, and forest tundra sites near treeline in northwestern Alaska, representing the major structural transitions expected in response to warming. In these sites, we measured aboveground net primary production (ANPP) and vegetation and soil carbon and nitrogen pools, and used these data to parameterize the Terrestrial Ecosystem Model. We simulated the response of carbon balance components to air temperature and precipitation trends during 1981-2000. In areas experiencing warmer and dryer conditions, Net Primary Production (NPP) decreased and heterotrophic respiration (R H ) increased, leading to a decrease in Net Ecosystem Production (NEP). In warmer and wetter conditions NPP increased, but the response was exceeded by an increase in R H ; therefore, NEP also decreased. Lastly, in colder and wetter regions, the increase in NPP exceeded a small decline in R H , leading to an increase in NEP. The net effect for the region was a slight gain in ecosystem carbon storage over the 20 year period. This research highlights the potential importance of spatial variability in ecosystem responses to climate change in assessing the response of carbon storage in northern Alaska over the last two decades. ?? Springer 2005.

  5. Carbon sequestration in Southeast Asian tropical peatlands over the Holocene period: large-scale hydrological controls

    Science.gov (United States)

    Dommain, R.; Couwenberg, J.; Cobb, A.; Gandois, L.; Kai, F.; Su'ut, N.; Abu Salim, K.; Harvey, C. F.; Glaser, P. H.; Joosten, H.

    2012-12-01

    support the hypothesis that the water table elevation and not temperature is the primary control of the carbon balance of tropical peatlands. The period of fastest peatland expansion and highest CAR was the wettest period in the Holocene with the lowest hydraulic gradient imposed by the highstand in sea-level. The period with the lowest and nearly quiescent CAR was associated with higher drought stress and a steeper hydraulic gradient, implying lower water tables. The remarkably high carbon sequestration rates of Southeast Asian peatlands can be explained by the high production of woody biomass throughout the year under waterlogged conditions. Woody organic matter is principally resistant to decomposition in an anaerobic setting causing rapid rates of carbon accumulation as long as the water table remains high. Increased drought severity, possibly in association with changes in the El Niño-Southern Oscillation under a warmer future climate could potentially switch Southeast Asian carbon sequestering peatlands to carbon sources.

  6. Tropical rain forest biogeochemistry in a warmer world: initial results from a novel warming experiment in a Puerto Rico tropical forest

    Science.gov (United States)

    Reed, S.; Cavaleri, M. A.; Alonso-Rodríguez, A. M.; Kimball, B. A.; Wood, T. E.

    2016-12-01

    Tropical forests represent one of the planet's most active biogeochemical engines. They account for the dominant proportion of Earth's live terrestrial plant biomass, nearly one-third of all soil carbon, and exchange more CO2 with the atmosphere than any other biome. In the coming decades, the tropics will experience extraordinary changes in temperature, and our understanding of how this warming will affect biogeochemical cycling remains notably poor. Given the large amounts of carbon tropical forests store and cycle, it is no surprise that our limited ability to characterize tropical forest responses to climate change may represent the largest hurdle in accurately predicting Earth's future climate. Here we describe initial results from the world's first tropical forest field warming experiment, where forest understory plants and soils are being warmed 4 °C above ambient temperatures. This Tropical Responses to Altered Climate Experiment (TRACE) was established in a rain forest in Puerto Rico to investigate the effects of increased temperature on key biological processes that control tropical forest carbon cycling, and to establish the steps that need to be taken to resolve the uncertainties surrounding tropical forest responses to warming. In this talk we will describe the experimental design, as well as the wide range of measurements being conducted. We will also present results from the initial phase of warming, including data on how increased temperatures from infrared lamp warming affected soil moisture, soil respiration rates, a suite of carbon pools, soil microbial biomass, nutrient availability, and the exchange of elements between leaf litter and soil. These data represent a first look into tropical rain forest responses to an experimentally-warmed climate in the field, and provide exciting insight into the non-linear ways tropical biogeochemical cycles respond to change. Overall, we strive to improve Earth System Model parameterization of the pools and

  7. Carbon uptake and water use in woodlands and forests in southern Australia during an extreme heat wave event in the "Angry Summer" of 2012/2013

    Science.gov (United States)

    van Gorsel, Eva; Wolf, Sebastian; Cleverly, James; Isaac, Peter; Haverd, Vanessa; Ewenz, Cäcilia; Arndt, Stefan; Beringer, Jason; Resco de Dios, Víctor; Evans, Bradley J.; Griebel, Anne; Hutley, Lindsay B.; Keenan, Trevor; Kljun, Natascha; Macfarlane, Craig; Meyer, Wayne S.; McHugh, Ian; Pendall, Elise; Prober, Suzanne M.; Silberstein, Richard

    2016-11-01

    As a result of climate change warmer temperatures are projected through the 21st century and are already increasing above modelled predictions. Apart from increases in the mean, warm/hot temperature extremes are expected to become more prevalent in the future, along with an increase in the frequency of droughts. It is crucial to better understand the response of terrestrial ecosystems to such temperature extremes for predicting land-surface feedbacks in a changing climate. While land-surface feedbacks in drought conditions and during heat waves have been reported from Europe and the US, direct observations of the impact of such extremes on the carbon and water cycles in Australia have been lacking. During the 2012/2013 summer, Australia experienced a record-breaking heat wave with an exceptional spatial extent that lasted for several weeks. In this study we synthesised eddy-covariance measurements from seven woodlands and one forest site across three biogeographic regions in southern Australia. These observations were combined with model results from BIOS2 (Haverd et al., 2013a, b) to investigate the effect of the summer heat wave on the carbon and water exchange of terrestrial ecosystems which are known for their resilience toward hot and dry conditions. We found that water-limited woodland and energy-limited forest ecosystems responded differently to the heat wave. During the most intense part of the heat wave, the woodlands experienced decreased latent heat flux (23 % of background value), increased Bowen ratio (154 %) and reduced carbon uptake (60 %). At the same time the forest ecosystem showed increased latent heat flux (151 %), reduced Bowen ratio (19 %) and increased carbon uptake (112 %). Higher temperatures caused increased ecosystem respiration at all sites (up to 139 %). During daytime all ecosystems remained carbon sinks, but carbon uptake was reduced in magnitude. The number of hours during which the ecosystem acted as a carbon sink was also reduced

  8. Large difference in carbon emission – burial balances between boreal and arctic lakes.

    Science.gov (United States)

    Lundin, E J; Klaminder, J; Bastviken, D; Olid, C; Hansson, S V; Karlsson, J

    2015-09-15

    Lakes play an important role in the global carbon (C) cycle by burying C in sediments and emitting CO2 and CH4 to the atmosphere. The strengths and control of these fundamentally different pathways are therefore of interest when assessing the continental C balance and its response to environmental change. In this study, based on new high-resolution estimates in combination with literature data, we show that annual emission:burial ratios are generally ten times higher in boreal compared to subarctic - arctic lakes. These results suggest major differences in lake C cycling between biomes, as lakes in warmer boreal regions emit more and store relatively less C than lakes in colder arctic regions. Such effects are of major importance for understanding climatic feedbacks on the continental C sink - source function at high latitudes. If predictions of global warming and northward expansion of the boreal biome are correct, it is likely that increasing C emissions from high latitude lakes will partly counteract the presumed increasing terrestrial C sink capacity at high latitudes.

  9. Ecohydrological and Biophysical Controls on Carbon Cycling in Two Seasonally Snow-covered Forests

    Science.gov (United States)

    Chan, A. M.; Brooks, P. D.; Burns, S. P.; Litvak, M. E.; Blanken, P.; Bowling, D. R.

    2014-12-01

    In many seasonally snow-covered forests, the snowpack is the primary water resource. The snowpack also serves as an insulating layer over the soil, warming soil throughout the winter and preserving moisture conditions from the preceding fall. Therefore, the total amount of water in the snowpack as well as the timing and duration of the snow-covered season are likely to have a strong influence on forest productivity through the regulation of the biophysical environment. We investigated how interannual variation in the amount and timing of seasonal snow cover affect winter carbon efflux and growing season carbon uptake at the Niwot Ridge AmeriFlux site (NWT) in Colorado (3050m a.s.l.; 40˚N) and the Valles Caldera Mixed-Conifer AmeriFlux site (VC) in New Mexico (3003m a.s.l.; 36˚N). The tree species composition at NWT is dominated by Abies lasiocarpa, Picea engelmannii, and Pinus contorta. At VC, the dominant tree species are Pseudotsuga menziesii, Abies concolor, Picea pungens, Pinus strobiformis, Pinus flexilis, Pinus ponderosa, and Populus tremuloides. We used net ecosystem exchange (NEE) and climate data from 1999-2012 at NWT and 2007-2012 at VC to divide each year into the growing season, when NEE is negative, and the winter, when NEE is positive. Snow water equivalent (SWE), precipitation, and duration of snow cover data were obtained from USDA/NRCS SNOTEL sites near each forest. At both sites, the start of the growing season was strongly controlled by air temperature, but growing season NEE was not dependent on the length of the growing season. At NWT, total winter carbon efflux was strongly influenced by both the amount and duration of the snowpack, measured as SWE integrated over time. Years with higher integrated SWE had higher winter carbon efflux and also had warmer soil under the snowpack. These patterns were not seen at VC. However, peak SWE amount was positively correlated with growing season NEE at VC, but not at NWT. These results suggest that

  10. Stable isotope analysis of Dacryoconarid carbonate microfossils: a new tool for Devonian oxygen and carbon isotope stratigraphy.

    Science.gov (United States)

    Frappier, Amy Benoit; Lindemann, Richard H; Frappier, Brian R

    2015-04-30

    Dacryoconarids are extinct marine zooplankton known from abundant, globally distributed calcite microfossils in the Devonian, but their shell stable isotope composition has not been previously explored. Devonian stable isotope stratigraphy is currently limited to less common invertebrates or bulk rock analyses of uncertain provenance. As with Cenozoic planktonic foraminifera, isotopic analysis of dacryoconarid shells could facilitate higher-resolution, geographically widespread stable isotope records of paleoenvironmental change, including marine hypoxia events, climate changes, and biocrises. We explored the use of Dacryoconarid isotope stratigraphy as a viable method in interpreting paleoenvironments. We applied an established method for determining stable isotope ratios (δ(13) C, δ(18) O values) of small carbonate microfossils to very well-preserved dacryoconarid shells. We analyzed individual calcite shells representing five common genera using a Kiel carbonate device coupled to a MAT 253 isotope ratio mass spectrometer. Calcite shell δ(13) C and δ(18) O values were compared by taxonomic group, rock unit, and locality. Single dacryoconarid calcite shells are suitable for stable isotope analysis using a Kiel-IRMS setup. The dacryoconarid shell δ(13) C values (-4.7 to 2.3‰) and δ(18) O values (-10.3 to -4.8‰) were consistent across taxa, independent of shell size or part, but varied systematically through time. Lower fossil δ(18) O values were associated with warmer water temperature and more variable δ(13) C values were associated with major bioevents. Dacryoconarid δ(13) C and δ(18) O values differed from bulk rock carbonate values. Dacryoconarid individual microfossil δ(13) C and δ(18) O values are highly sensitive to paleoenvironmental changes, thus providing a promising avenue for stable isotope chemostratigraphy to better resolve regional to global paleoceanographic changes throughout the upper Silurian to the upper Devonian. Our results

  11. Globalisation and Higher Education

    NARCIS (Netherlands)

    Marginson, Simon; van der Wende, Marijk

    2007-01-01

    Economic and cultural globalisation has ushered in a new era in higher education. Higher education was always more internationally open than most sectors because of its immersion in knowledge, which never showed much respect for juridical boundaries. In global knowledge economies, higher education

  12. India's Higher Education Challenges

    Science.gov (United States)

    Altbach, Philip G.

    2014-01-01

    India, with the world's second largest higher education system and a rapidly growing economy as one of the BRIC nations, faces significant challenges in building both capacity and excellence in higher education. India's higher education system is characterized by "islands of excellence in a sea of mediocrity." The mainstream universities…

  13. Carbon isotopes in mollusk shell carbonates

    Science.gov (United States)

    McConnaughey, Ted A.; Gillikin, David Paul

    2008-10-01

    Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod shell carbonates. Land snails construct their shells mainly from respired CO2, and shell δ13C reflects the local mix of C3 and C4 plants consumed. Shell δ13C is typically >10‰ heavier than diet, probably because respiratory gas exchange discards CO2, and retains the isotopically heavier HCO3 -. Respired CO2 contributes less to the shells of aquatic mollusks, because CO2/O2 ratios are usually higher in water than in air, leading to more replacement of respired CO2 by environmental CO2. Fluid exchange with the environment also brings additional dissolved inorganic carbon (DIC) into the calcification site. Shell δ13C is typically a few ‰ lower than ambient DIC, and often decreases with age. Shell δ13C retains clues about processes such as ecosystem metabolism and estuarine mixing. Ca2+ ATPase-based models of calcification physiology developed for corals and algae likely apply to mollusks, too, but lower pH and carbonic anhydrase at the calcification site probably suppress kinetic isotope effects. Carbon isotopes in biogenic carbonates are clearly complex, but cautious interpretation can provide a wealth of information, especially after vital effects are better understood.

  14. Comparative accounts of biological productivity characteristics and estimates of carbon fluxes in the Arabian Sea and the Bay of Bengal

    Science.gov (United States)

    Gauns, Mangesh; Madhupratap, M.; Ramaiah, N.; Jyothibabu, R.; Fernandes, Veronica; Paul, Jane T.; Prasanna Kumar, S.

    2005-07-01

    The Arabian Sea and the Bay of Bengal are tropical basins experiencing monsoonal wind forcing that reverses semi-annually. This brings changes in physics, chemistry and biology of the upper water column on a seasonal scale and ultimately regulates the sinking fluxes of the region. An attempt is made here to focus on factors responsible for fluxes of carbon from the upper layers to the deep sea. Higher fluxes are observed during southwest and northeast monsoon season in both the regions. In contrast to the Arabian Sea, an immense quantity of freshwater runoff together with warmer SST (˜30 °C) makes the northern bay strongly stratified. The runoff also brings in billions of tonnes of fluvial matter as well. Stratification constrains subsurface nutrient input into the surface waters thereby reducing the primary production in the Bay of Bengal. The total living carbon content in the Bay of Bengal is much lower than in the Arabian Sea. Higher downward fluxes associated with deep mixed layer and high production in the Arabian Sea during summer and winter pinpoint importance of strong winds causing mixing and upwelling during summer and evaporative cooling and convection during winter. Inability of the low-speed winds to break the stratification in the Bay of Bengal keeps the region low productive throughout the year. Therefore, river water associated with the terrigenous material due to ballast effect appears to swipe off surface producers to the deep, thereby increasing the downward fluxes of total particulates, which are sometimes even higher than that of the more productive Arabian Sea.

  15. [Higher Brain Dysfunction].

    Science.gov (United States)

    Kashima, Haruo

    2015-01-01

    The technical term "higher brain dysfunction" is used widely in Japan. However, it is not always clear what "higher" means. The author thinks that the term "higher" is understood as being associated with a meaning. In this article, the differences between higher brain dysfunctions and elementary brain dysfunctions are discussed from the point of view of lesion localization and the consistency of symptoms. The psychiatric approach is indispensable for the assessment of higher brain dysfunction. A simple test for mild Alzheimer-type dementia is also introduced.

  16. Calcium Carbonate

    Science.gov (United States)

    Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not ... for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used as an antacid to relieve ...

  17. Higher derivative mimetic gravity

    Science.gov (United States)

    Gorji, Mohammad Ali; Mansoori, Seyed Ali Hosseini; Firouzjahi, Hassan

    2018-01-01

    We study cosmological perturbations in mimetic gravity in the presence of classified higher derivative terms which can make the mimetic perturbations stable. We show that the quadratic higher derivative terms which are independent of curvature and the cubic higher derivative terms which come from curvature corrections are sufficient to remove instabilities in mimetic perturbations. The classified higher derivative terms have the same dimensions but they contribute differently in the background and perturbed equations. Therefore, we can control both the background and the perturbation equations allowing us to construct the higher derivative extension of mimetic dark matter and the mimetic nonsingular bouncing scenarios. The latter can be thought as a new higher derivative effective action for the loop quantum cosmology scenario in which the equations of motion coincide with those suggested by loop quantum cosmology. We investigate a possible connection between the mimetic cosmology and the Randall-Sundrum cosmology.

  18. Higher Spin Matrix Models

    Directory of Open Access Journals (Sweden)

    Mauricio Valenzuela

    2017-10-01

    Full Text Available We propose a hybrid class of theories for higher spin gravity and matrix models, i.e., which handle simultaneously higher spin gravity fields and matrix models. The construction is similar to Vasiliev’s higher spin gravity, but part of the equations of motion are provided by the action principle of a matrix model. In particular, we construct a higher spin (gravity matrix model related to type IIB matrix models/string theory that have a well defined classical limit, and which is compatible with higher spin gravity in A d S space. As it has been suggested that higher spin gravity should be related to string theory in a high energy (tensionless regime, and, therefore to M-Theory, we expect that our construction will be useful to explore concrete connections.

  19. High performance ultracapacitors with carbon nanomaterials and ionic liquids

    Science.gov (United States)

    Lu, Wen; Henry, Kent Douglas

    2012-10-09

    The present invention is directed to the use of carbon nanotubes and/or electrolyte structures in various electrochemical devices, such as ultracapacitors having an ionic liquid electrolyte. The carbon nanotubes are preferably aligned carbon nanotubes. Compared to randomly entangled carbon nanotubes, aligned carbon nanotubes can have better defined pore structures and higher specific surface areas.

  20. Higher dimensional higher derivative ϕ4 theory

    Science.gov (United States)

    Gracey, J. A.; Simms, R. M.

    2017-07-01

    We construct several towers of scalar quantum field theories with an O (N ) symmetry which have higher derivative kinetic terms. The Lagrangians in each tower are connected by lying in the same universality class at the d -dimensional Wilson-Fisher fixed point. Moreover the universal theory is studied using the large N expansion and we determine d -dimensional critical exponents to O (1 /N2). We show that these new universality classes emerge naturally as solutions to the linear relation of the dimensions of the fields deduced from the underlying force-matter interaction of the universal critical theory. To substantiate the equivalence of the Lagrangians in each tower we renormalize each to several loop orders and show that the renormalization group functions are consistent with the large N critical exponents. While we focus on the first two new towers of theories and renormalize the respective Lagrangians to 16 and 18 dimensions there are an infinite number of such towers. We also briefly discuss the conformal windows and the extension of the ideas to theories with spin-1/2 and spin-1 fields as well as the idea of lower dimension completeness.

  1. Impact of warming and drought on carbon balance related to wood formation in black spruce.

    Science.gov (United States)

    Deslauriers, Annie; Beaulieu, Marilène; Balducci, Lorena; Giovannelli, Alessio; Gagnon, Michel J; Rossi, Sergio

    2014-08-01

    Wood formation in trees represents a carbon sink that can be modified in the case of stress. The way carbon metabolism constrains growth during stress periods (high temperature and water deficit) is now under debate. In this study, the amounts of non-structural carbohydrates (NSCs) for xylogenesis in black spruce, Picea mariana, saplings were assessed under high temperature and drought in order to determine the role of sugar mobilization for osmotic purposes and its consequences for secondary growth. Four-year-old saplings of black spruce in a greenhouse were subjected to different thermal conditions with respect to the outside air temperature (T0) in 2010 (2 and 5 °C higher than T0) and 2011 (6 °C warmer than T0 during the day or night) with a dry period of about 1 month in June of each year. Wood formation together with starch, NSCs and leaf parameters (water potential and photosynthesis) were monitored from May to September. With the exception of raffinose, the amounts of soluble sugars were not modified in the cambium even if gas exchange and photosynthesis were greatly reduced during drought. Raffinose increased more than pinitol under a pre-dawn water potential of less than -1 Mpa, presumably because this compound is better suited than polyol for replacing water and capturing free radicals, and its degradation into simple sugar is easier. Warming decreased the starch storage in the xylem as well the available hexose pool in the cambium and the xylem, probably because of an increase in respiration. Radial stem growth was reduced during drought due to the mobilization of NSCs for osmotic purposes and due to the lack of cell turgor. Thus plant water status during wood formation can influence the NSCs available for growth in the cambium and xylem. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Cost in Higher Education

    Science.gov (United States)

    2007-06-01

    standardize methodology and accountability used nationwide by institutions of higher education . The aim is to review existing cost criteria and procedures...task. The objective of this research is to look into the cost structure used presently by two institutions of higher education , namely the Naval

  3. Higher Education in California

    Science.gov (United States)

    Public Policy Institute of California, 2016

    2016-01-01

    Higher education enhances Californians' lives and contributes to the state's economic growth. But population and education trends suggest that California is facing a large shortfall of college graduates. Addressing this short­fall will require strong gains for groups that have been historically under­represented in higher education. Substantial…

  4. Reputation in Higher Education

    DEFF Research Database (Denmark)

    Plewa, Carolin; Ho, Joanne; Conduit, Jodie

    2016-01-01

    Reputation is critical for institutions wishing to attract and retain students in today's competitive higher education setting. Drawing on the resource based view and configuration theory, this research proposes that Higher Education Institutions (HEIs) need to understand not only the impact...

  5. Happiness in Higher Education

    Science.gov (United States)

    Elwick, Alex; Cannizzaro, Sara

    2017-01-01

    This paper investigates the higher education literature surrounding happiness and related notions: satisfaction, despair, flourishing and well-being. It finds that there is a real dearth of literature relating to profound happiness in higher education: much of the literature using the terms happiness and satisfaction interchangeably as if one were…

  6. Reimagining Christian Higher Education

    Science.gov (United States)

    Hulme, E. Eileen; Groom, David E., Jr.; Heltzel, Joseph M.

    2016-01-01

    The challenges facing higher education continue to mount. The shifting of the U.S. ethnic and racial demographics, the proliferation of advanced digital technologies and data, and the move from traditional degrees to continuous learning platforms have created an unstable environment to which Christian higher education must adapt in order to remain…

  7. Consumerism in Higher Education

    Science.gov (United States)

    Green, Mark

    1973-01-01

    In considering consumerism in higher education, the student becomes the consumer,'' the university the corporation,'' and higher education the education industry.'' Other members of the education fraternity become investors, management, workers, direct consumers, and indirect consumers. This article proposes that it behooves the student to…

  8. Black carbon solar absorption suppresses turbulence in the atmospheric boundary layer.

    Science.gov (United States)

    Wilcox, Eric M; Thomas, Rick M; Praveen, Puppala S; Pistone, Kristina; Bender, Frida A-M; Ramanathan, Veerabhadran

    2016-10-18

    The introduction of cloud condensation nuclei and radiative heating by sunlight-absorbing aerosols can modify the thickness and coverage of low clouds, yielding significant radiative forcing of climate. The magnitude and sign of changes in cloud coverage and depth in response to changing aerosols are impacted by turbulent dynamics of the cloudy atmosphere, but integrated measurements of aerosol solar absorption and turbulent fluxes have not been reported thus far. Here we report such integrated measurements made from unmanned aerial vehicles (UAVs) during the CARDEX (Cloud Aerosol Radiative Forcing and Dynamics Experiment) investigation conducted over the northern Indian Ocean. The UAV and surface data reveal a reduction in turbulent kinetic energy in the surface mixed layer at the base of the atmosphere concurrent with an increase in absorbing black carbon aerosols. Polluted conditions coincide with a warmer and shallower surface mixed layer because of aerosol radiative heating and reduced turbulence. The polluted surface mixed layer was also observed to be more humid with higher relative humidity. Greater humidity enhances cloud development, as evidenced by polluted clouds that penetrate higher above the top of the surface mixed layer. Reduced entrainment of dry air into the surface layer from above the inversion capping the surface mixed layer, due to weaker turbulence, may contribute to higher relative humidity in the surface layer during polluted conditions. Measurements of turbulence are important for studies of aerosol effects on clouds. Moreover, reduced turbulence can exacerbate both the human health impacts of high concentrations of fine particles and conditions favorable for low-visibility fog events.

  9. Quality of Higher Education

    DEFF Research Database (Denmark)

    Zou, Yihuan

    is about constructing a more inclusive understanding of quality in higher education through combining the macro, meso and micro levels, i.e. from the perspectives of national policy, higher education institutions as organizations in society, individual teaching staff and students. It covers both......Quality in higher education was not invented in recent decades – universities have always possessed mechanisms for assuring the quality of their work. The rising concern over quality is closely related to the changes in higher education and its social context. Among others, the most conspicuous...... changes are the massive expansion, diversification and increased cost in higher education, and new mechanisms of accountability initiated by the state. With these changes the traditional internally enacted academic quality-keeping has been given an important external dimension – quality assurance, which...

  10. Higher English for CFE

    CERN Document Server

    Bridges, Ann; Mitchell, John

    2015-01-01

    A brand new edition of the former Higher English: Close Reading , completely revised and updated for the new Higher element (Reading for Understanding, Analysis and Evaluation) - worth 30% of marks in the final exam!. We are working with SQA to secure endorsement for this title. Written by two highly experienced authors this book shows you how to practice for the Reading for Understanding, Analysis and Evaluation section of the new Higher English exam. This book introduces the terms and concepts that lie behind success and offers guidance on the interpretation of questions and targeting answer

  11. Reputation in Higher Education

    DEFF Research Database (Denmark)

    Martensen, Anne; Grønholdt, Lars

    2005-01-01

    The purpose of this paper is to develop a reputation model for higher education programmes, provide empirical evidence for the model and illustrate its application by using Copenhagen Business School (CBS) as the recurrent case. The developed model is a cause-and-effect model linking image...... for higher education reputation and which relations exist between the included determinants from a theoretical perspective. It is demonstrated how the model and measurement system may be a useful management tool for the improvement of the reputation of a higher education. In this way, the model can help...... leaders of higher education institutions to set strategic directions and support their decisions in an effort to create even better study programmes with a better reputation. Finally, managerial implications and directions for future research are discussed.Keywords: Reputation, image, corporate identity...

  12. Higher Education in Scandinavia

    DEFF Research Database (Denmark)

    Nielsen, Jørgen Lerche; Birch Andreasen, Lars

    2015-01-01

    Higher education systems around the world have been undergoing fundamental changes through the last 50 years from more narrow self-sustaining universities for the elite and into mass universities, where new groups of students have been recruited and the number of students enrolled has increased....... In this chapter we will examine how higher education systems in Scandinavia are developing in relation to these challenges. To what extent has the democratic tradition had an impact on the educational systems, and what possible futures can be envisioned? In the development of higher education in Scandinavia......, there are different perspectives on education at play. One perspective sees education as a “public good” that benefits society and therefore should be free and accessible for all students who qualify to be admitted. According to this perspective, one of the main purposes of higher education is to add value to all...

  13. Wetlands receiving water treated with coagulants improve water quality by removing dissolved organic carbon and disinfection byproduct precursors.

    Science.gov (United States)

    Hansen, Angela M; Kraus, Tamara E C; Bachand, Sandra M; Horwath, William R; Bachand, Philip A M

    2017-12-06

    Constructed wetlands are used worldwide to improve water quality while also providing critical wetland habitat. However, wetlands have the potential to negatively impact drinking water quality by exporting dissolved organic carbon (DOC) that upon disinfection can form disinfection byproducts (DBPs) like trihalomethanes (THMs) and haloacetic acids (HAAs). We used a replicated field-scale study located on organic rich soils in California's Sacramento-San Joaquin Delta to test whether constructed flow-through wetlands which receive water high in DOC that is treated with either iron- or aluminum-based coagulants can improve water quality with respect to DBP formation. Coagulation alone removed DOC (66-77%) and THM (67-70%) precursors, and was even more effective at removing HAA precursors (77-90%). Passage of water through the wetlands increased DOC concentrations (1.5-7.5mgL-1), particularly during the warmer summer months, thereby reversing some of the benefits from coagulant addition. Despite this addition, water exiting the wetlands treated with coagulants had lower DOC and DBP precursor concentrations relative to untreated source water. Benefits of the coagulation-wetland systems were greatest during the winter months (approx. 50-70% reduction in DOC and DBP precursor concentrations) when inflow water DOC concentrations were higher and wetland DOC production was lower. Optical properties suggest DOC in this system is predominantly comprised of high molecular weight, aromatic compounds, likely derived from degraded peat soils. Published by Elsevier B.V.

  14. Higher Spins & Strings

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    The conjectured relation between higher spin theories on anti de-Sitter (AdS) spaces and weakly coupled conformal field theories is reviewed. I shall then outline the evidence in favour of a concrete duality of this kind, relating a specific higher spin theory on AdS3 to a family of 2d minimal model CFTs. Finally, I shall explain how this relation fits into the framework of the familiar stringy AdS/CFT correspondence.

  15. INTERNATIONALIZATION IN HIGHER EDUCATION

    OpenAIRE

    Catalina Crisan-Mitra; Anca Borza

    2015-01-01

    Internationalization of higher education is one of the key trends of development. There are several approaches on how to achieve competitiveness and performance in higher education and international academic mobility; students’ exchange programs, partnerships are some of the aspects that can play a significant role in this process. This paper wants to point out the student’s perception regarding two main directions: one about the master students’ expectation regarding how an internationalized...

  16. Effects of slope aspect and site elevation on seasonal soil carbon dynamics in a forest catchment in the Austrian Limestone Alps

    Science.gov (United States)

    Kobler, Johannes; Zehetgruber, Bernhard; Jandl, Robert; Dirnböck, Thomas; Schindlbacher, Andreas

    2017-04-01

    Own to the complexity of landscape morphology, mountainous landscapes are characterized by substantial changes of site parameters (i.e. elevation, slope, aspect) within short distances. As these site parameters affect the spatial-temporal dynamics of landscape climate and therefore the spatial patterns of forest carbon (C) distribution, they pose a substantial impact on landscape-related soil C dynamics. Aspect and elevation form natural temperature gradients and thereby can be used as a surrogate to infer to potential climate change effects on forest C. We aimed at studying how slope aspect affected soil respiration, soil C stocks, tree increment and litter production along two elevation gradients in the Zöbelboden catchment, northern limestone Alps, Austria during 2015 and 2016. A preliminary assessment showed that soil respiration was significantly higher at the west facing slope across all elevations. Soil temperature was only slightly higher at the west facing slope, and warmer soil only partly explained the large difference in soil respiration between east and west facing slopes. Aspect had no clear effect on soil moisture, which seemed to be strongly affected by stocking density at the different forest sites. The dense grassy ground vegetation at some of the sites further seems to play a key role in determining soil respiration rates and litter input. A detailed analysis and C-budgets along the elevation gradients will be presented at the conference.

  17. Supported molybdenum carbide for higher alcohol synthesis from syngas

    DEFF Research Database (Denmark)

    Wu, Qiongxiao; Christensen, Jakob Munkholt; Chiarello, Gian Luca

    2013-01-01

    carbide, while the selectivity to methanol follows the opposite trend. The effect of Mo2C loading on the alcohol selectivity at a fixed K/Mo molar ratio of 0.14 could be related to the amount of K2CO3 actually on the active Mo2C phase and the size, structure and composition of the supported carbide......Molybdenum carbide supported on active carbon, carbon nanotubes, and titanium dioxide, and promoted by K2CO3, has been prepared and tested for methanol and higher alcohol synthesis from syngas. At optimal conditions, the activity and selectivity to alcohols (methanol and higher alcohols) over...... supported molybdenum carbide are significantly higher compared to the bulk carbide. The CO conversion reaches a maximum, when about 20wt% Mo2C is loaded on active carbon. The selectivity to higher alcohols increases with increasing Mo2C loading on active carbon and reaches a maximum over bulk molybdenum...

  18. Vulnerability of carbon storage in North American boreal forests to wildfires during the 21st century

    Science.gov (United States)

    Balshi, M. S.; McGuire, Anthony David; Duffy, P.; Flannigan, M.; Kicklighter, David W.; Melillo, J.

    2009-01-01

    The boreal forest contains large reserves of carbon. Across this region, wildfires influence the temporal and spatial dynamics of carbon storage. In this study, we estimate fire emissions and changes in carbon storage for boreal North America over the 21st century. We use a gridded data set developed with a multivariate adaptive regression spline approach to determine how area burned varies each year with changing climatic and fuel moisture conditions. We apply the process-based Terrestrial Ecosystem Model to evaluate the role of future fire on the carbon dynamics of boreal North America in the context of changing atmospheric carbon dioxide (CO2) concentration and climate in the A2 and B2 emissions scenarios of the CGCM2 global climate model. Relative to the last decade of the 20th century, decadal total carbon emissions from fire increase by 2.5–4.4 times by 2091–2100, depending on the climate scenario and assumptions about CO2fertilization. Larger fire emissions occur with warmer climates or if CO2 fertilization is assumed to occur. Despite the increases in fire emissions, our simulations indicate that boreal North America will be a carbon sink over the 21st century if CO2 fertilization is assumed to occur in the future. In contrast, simulations excluding CO2 fertilization over the same period indicate that the region will change to a carbon source to the atmosphere, with the source being 2.1 times greater under the warmer A2 scenario than the B2 scenario. To improve estimates of wildfire on terrestrial carbon dynamics in boreal North America, future studies should incorporate the role of dynamic vegetation to represent more accurately post-fire successional processes, incorporate fire severity parameters that change in time and space, account for human influences through increased fire suppression, and integrate the role of other disturbances and their interactions with future fire regime.

  19. Esterification of glycerol from biodiesel production to glycerol carbonate in non-catalytic supercritical dimethyl carbonate

    OpenAIRE

    Ilham, Zul; Saka, Shiro

    2016-01-01

    Conversion of glycerol from biodiesel production to glycerol carbonate was studied by esterification with dimethyl carbonate in a non-catalytic supercritical condition. It was found that in a non-catalytic supercritical condition, glycerol at higher purity gave higher yield of glycerol carbonate at 98 wt% after reaction at 300??C/20?40?MPa/15?min. The yield of glycerol carbonate was observed to increase with molar ratio, temperature, pressure and time until a certain equilibrium limit. The ex...

  20. Impact of Different Carbon Policies on City Logistics Network

    Directory of Open Access Journals (Sweden)

    Yang Jianhua

    2015-01-01

    Full Text Available A programming model for a four-layer urban logistics distribution network is constructed and revised based on three types of carbon emissions policies such as Carbon tax, carbon emissions Cap, Carbon Trade. Effects of different policies on logistics costs and carbon emissions are analyzed based on a spatial Logistics Infrastructure layout of Beijing. Research findings are as follows: First, based on low-carbon policies, the logistics costs and carbon emissions can be changed by different modes of transport in a certain extent; second, only when carbon taxes and carbon trading prices are higher, carbon taxes and carbon trading policies can reduce carbon emissions while not significantly increase logistics costs at the same time, and more effectively achieve carbon reduction targets than use carbon cap policy.

  1. Quality of Higher Education

    DEFF Research Database (Denmark)

    Zou, Yihuan; Zhao, Yingsheng; Du, Xiangyun

    . This transformation involves a broad scale of change at individual level, organizational level, and societal level. In this change process in higher education, staff development remains one of the key elements for university innovation and at the same time demands a systematic and holistic approach.......This paper starts with a critical approach to reflect on the current practice of quality assessment and assurance in higher education. This is followed by a proposal that in response to the global challenges for improving the quality of higher education, universities should take active actions...... of change by improving the quality of teaching and learning. From a constructivist perspective of understanding education and learning, this paper also discusses why and how universities should give more weight to learning and change the traditional role of teaching to an innovative approach of facilitation...

  2. INTERNATIONALIZATION IN HIGHER EDUCATION

    Directory of Open Access Journals (Sweden)

    Catalina Crisan-Mitra

    2016-03-01

    Full Text Available Internationalization of higher education is one of the key trends of development. There are several approaches on how to achieve competitiveness and performance in higher education and international academic mobility; students’ exchange programs, partnerships are some of the aspects that can play a significant role in this process. This paper wants to point out the student’s perception regarding two main directions: one about the master students’ expectation regarding how an internationalized master should be organized and should function, and second the degree of satisfaction of the beneficiaries of internationalized master programs from Babe-Bolyai University. This article is based on an empirical qualitative research that was implemented to students of an internationalized master from the Faculty of Economics and Business Administration. This research can be considered a useful example for those preoccupied to increase the quality of higher education and conclusions drawn have relevance both theoretically and especially practically.

  3. Higher spin gauge theories

    CERN Document Server

    Henneaux, Marc; Vasiliev, Mikhail A

    2017-01-01

    Symmetries play a fundamental role in physics. Non-Abelian gauge symmetries are the symmetries behind theories for massless spin-1 particles, while the reparametrization symmetry is behind Einstein's gravity theory for massless spin-2 particles. In supersymmetric theories these particles can be connected also to massless fermionic particles. Does Nature stop at spin-2 or can there also be massless higher spin theories. In the past strong indications have been given that such theories do not exist. However, in recent times ways to evade those constraints have been found and higher spin gauge theories have been constructed. With the advent of the AdS/CFT duality correspondence even stronger indications have been given that higher spin gauge theories play an important role in fundamental physics. All these issues were discussed at an international workshop in Singapore in November 2015 where the leading scientists in the field participated. This volume presents an up-to-date, detailed overview of the theories i...

  4. Entrepreneurship and Higher Education

    Science.gov (United States)

    Potter, Jonathan, Ed.

    2008-01-01

    Stimulating innovative and growth-oriented entrepreneurship is a key economic and societal challenge to which universities and colleges have much to contribute. This book examines the role that higher education institutions are currently playing through teaching entrepreneurship and transferring knowledge and innovation to enterprises and…

  5. Liberty and Higher Education.

    Science.gov (United States)

    Thompson, Dennis F.

    1989-01-01

    John Stuart Mill's principle of liberty is discussed with the view that it needs to be revised to guide moral judgments in higher education. Three key elements need to be modified: the action that is constrained; the constraint on the action; and the agent whose action is constrained. (MLW)

  6. Navigating in higher education

    DEFF Research Database (Denmark)

    Thingholm, Hanne Balsby; Reimer, David; Keiding, Tina Bering

    Denne rapport er skrevet på baggrund af spørgeskemaundersøgelsen – Navigating in Higher Education (NiHE) – der rummer besvarelser fra 1410 bachelorstuderende og 283 undervisere fordelt på ni uddannelser fra Aarhus Universitet: Uddannelsesvidenskab, Historie, Nordisk sprog og litteratur...

  7. California's Future: Higher Education

    Science.gov (United States)

    Johnson, Hans

    2015-01-01

    California's higher education system is not keeping up with the changing economy. Projections suggest that the state's economy will continue to need more highly educated workers. In 2025, if current trends persist, 41 percent of jobs will require at least a bachelor's degree and 36 percent will require some college education short of a bachelor's…

  8. Higher-level Innovization

    DEFF Research Database (Denmark)

    Bandaru, Sunith; Tutum, Cem Celal; Deb, Kalyanmoy

    2011-01-01

    we introduce the higher-level innovization task through an application of a manufacturing process simulation for the Friction Stir Welding (FSW) process where commonalities among two different Pareto-optimal fronts are analyzed. Multiple design rules are simultaneously deciphered from each front...

  9. Cyberbullying in Higher Education

    Science.gov (United States)

    Minor, Maria A.; Smith, Gina S.; Brashen, Henry

    2013-01-01

    Bullying has extended beyond the schoolyard into online forums in the form of cyberbullying. Cyberbullying is a growing concern due to the effect on its victims. Current studies focus on grades K-12; however, cyberbullying has entered the world of higher education. The focus of this study was to identify the existence of cyberbullying in higher…

  10. Creativity in Higher Education

    Science.gov (United States)

    Gaspar, Drazena; Mabic, Mirela

    2015-01-01

    The paper presents results of research related to perception of creativity in higher education made by the authors at the University of Mostar from Bosnia and Herzegovina. This research was based on a survey conducted among teachers and students at the University. The authors developed two types of questionnaires, one for teachers and the other…

  11. Evaluation in Higher Education

    Science.gov (United States)

    Bognar, Branko; Bungic, Maja

    2014-01-01

    One of the means of transforming classroom experience is by conducting action research with students. This paper reports about the action research with university students. It has been carried out within a semester of the course "Methods of Upbringing". Its goal has been to improve evaluation of higher education teaching. Different forms…

  12. Pedagogy in Higher Education

    Directory of Open Access Journals (Sweden)

    Jorge Luis Dahik Cabrera

    2016-06-01

    Full Text Available This review determines the factors that should involve the current education from a university pedagogy that addresses sociological, psychological, axiological, cultural and economic conditions; also highlighting the skills to be addressed by the teacher in the knowledge society and the relevant number of functions that higher education institutions should be attributed it.

  13. Pedagogy in Higher Education

    OpenAIRE

    Jorge Luis Dahik Cabrera

    2016-01-01

    This review determines the factors that should involve the current education from a university pedagogy that addresses sociological, psychological, axiological, cultural and economic conditions; also highlighting the skills to be addressed by the teacher in the knowledge society and the relevant number of functions that higher education institutions should be attributed it.

  14. Leadership in Higher Education.

    Science.gov (United States)

    Robles, Harriett J.

    This paper examines leadership in higher education, specifically in community colleges. The first section reviews current definitions and theories of education, including transactional leadership (where there is an exchange between the leader and the follower) and transformational leadership (where the leader tries to change the framework itself…

  15. Competitiveness - Higher Education

    National Research Council Canada - National Science Library

    Labas, Istvan; Darabos, Eva; Nagy, Tunde Orsolya

    2016-01-01

    ... economy. In recent years, the frameworks of operation of higher education systems have gone through a total transformation. The number of applying students is continuously decreasing in some European countries therefore only those institutions can "survive" this shortfall, which are able to minimize the loss of the number of students. In...

  16. Futurism in Higher Education.

    Science.gov (United States)

    Fazio, Linda S.

    1988-01-01

    The concept of "futurism" in higher education program planning, self-study and goal setting is taking on increasing significance. Two research techniques for "futures forecasting" are discussed: the Delphi and the Scenario. These techniques have been used successfully in institutional self-study and program evaluation.…

  17. Higher-Order Hierarchies

    DEFF Research Database (Denmark)

    Ernst, Erik

    2003-01-01

    This paper introduces the notion of higher-order inheritance hierarchies. They are useful because they provide well-known benefits of object-orientation at the level of entire hierarchies-benefits which are not available with current approaches. Three facets must be adressed: First, it must...

  18. Improving predictions of carbon fluxes in the tropics undre climatic changes using ED2

    Science.gov (United States)

    Feng, X.; Uriarte, M.

    2016-12-01

    Tropical forests play a critical role in the exchange of carbon between land and atmosphere, highlighting the urgency of understanding the effects of climate change on these ecosystems. The most optimistic predictions of climate models indicate that global mean temperatures will increase by up to 2 0C with some tropical regions experiencing extreme heat. Drought and heat-induced tree mortality will accelerate the release of carbon to the atmosphere creating a positive feedback that greatly exacerbates global warming. Thus, under a warmer and drier climate, tropical forests may become net sources, rather than sinks, of carbon. Earth system models have not reached a consensus on the magnitude and direction of climate change impacts on tropical forests, calling into question the reliability of their predictions. Thus, there is an immediate need to improve the representation of tropical forests in earth system models to make robust predictions. The goal of our study is to quantify the responses of tropical forests to climate variability and improve the predictive capacity of terrestrial ecosystem models. We have collected species-specific physiological and functional trait data from 144 tree species in a Puerto Rican rainforest to parameterize the Ecosystem Demography model (ED2). The large amount of data generated by this research will lead to better validation and lowering the uncertainty in future model predictions. To best represent the forest landscape in ED2, all the trees have been assigned to three plant functional types (PFTs): early, mid, and late successional species. Trait data for each PFT were synthesized in a Bayesian meta-analytical model and posterior distributions of traits were used to parameterize the ED2 model. Model predictions show that biomass production of late successional PFT (118.89 ton/ha) was consistently higher than mid (71.33 ton/ha) and early (13.21 ton/ha) PFTs. However, mid successional PFT had the highest contributions to NPP for the

  19. Stable carbon isotopic signature of methane from high-emitting wetland sites in discontinuous permafrost landscape

    Science.gov (United States)

    Marushchak, Maija; Liimatainen, Maarit; Lind, Saara; Biasi, Christina; Martikainen, Pertti

    2017-04-01

    . The latter cannot be explained by greater dominance of acetoclastic methanogenesis on densely vegetated sites, since this would lead to the opposite: more enriched methane with higher LAI. While the spatial variability of methane emission was related to the differences in the vascular plant cover, the seasonal dynamics followed closely the local temperatures. Height of the water table level was an unimportant regulator of methane emissions in these fens, where floating peat surface follows the water table fluctuations. This implies that these fens have high potential for increased methane release in the future warmer climate, due to enhanced microbial methane production and vascular plant growth.

  20. How will organic carbon stocks in mineral soils evolve under future climate? Global projections using RothC for a range of climate change scenarios

    Directory of Open Access Journals (Sweden)

    P. Gottschalk

    2012-08-01

    Full Text Available We use a soil carbon (C model (RothC, driven by a range of climate models for a range of climate scenarios to examine the impacts of future climate on global soil organic carbon (SOC stocks. The results suggest an overall global increase in SOC stocks by 2100 under all scenarios, but with a different extent of increase among the climate model and emissions scenarios. The impacts of projected land use changes are also simulated, but have relatively minor impacts at the global scale. Whether soils gain or lose SOC depends upon the balance between C inputs and decomposition. Changes in net primary production (NPP change C inputs to the soil, whilst decomposition usually increases under warmer temperatures, but can also be slowed by decreased soil moisture. Underlying the global trend of increasing SOC under future climate is a complex pattern of regional SOC change. SOC losses are projected to occur in northern latitudes where higher SOC decomposition rates due to higher temperatures are not balanced by increased NPP, whereas in tropical regions, NPP increases override losses due to higher SOC decomposition. The spatial heterogeneity in the response of SOC to changing climate shows how delicately balanced the competing gain and loss processes are, with subtle changes in temperature, moisture, soil type and land use, interacting to determine whether SOC increases or decreases in the future. Our results suggest that we should stop looking for a single answer regarding whether SOC stocks will increase or decrease under future climate, since there is no single answer. Instead, we should focus on improving our prediction of the factors that determine the size and direction of change, and the land management practices that can be implemented to protect and enhance SOC stocks.

  1. Carbon-On-Carbon Manufacturing

    Science.gov (United States)

    Mungas, Gregory S. (Inventor); Buchanan, Larry (Inventor); Banzon, Jr., Jose T. (Inventor)

    2017-01-01

    The presently disclosed technology relates to carbon-on-carbon (C/C) manufacturing techniques and the resulting C/C products. One aspect of the manufacturing techniques disclosed herein utilizes two distinct curing operations that occur at different times and/or using different temperatures. The resulting C/C products are substantially non-porous, even though the curing operation(s) substantially gasify a liquid carbon-entrained filler material that saturates a carbon fabric that makes up the C/C products.

  2. Higher spins and holography

    Science.gov (United States)

    Kraus, Per; Ross, Simon F.

    2013-05-01

    The principles of quantum mechanics and relativity impose rigid constraints on theories of massless particles with nonzero spin. Indeed, Yang-Mills theory and General Relativity are the unique solution in the case of spin-1 and spin-2. In asymptotically flat spacetime, there are fundamental obstacles to formulating fully consistent interacting theories of particles of spin greater than 2. However, indications are that such theories are just barely possible in asymptotically anti-de Sitter or de Sitter spacetimes, where the non-existence of an S-matrix provides an escape from the theorems restricting theories in Minkowski spacetime. These higher spin gravity theories are therefore of great intrinsic interest, since they, along with supergravity, provide the only known field theories generalizing the local invariance principles of Yang-Mills theory and General Relativity. While work on higher spin gravity goes back several decades, the subject has gained broader appeal in recent years due to its appearance in the AdS/CFT correspondence. In three and four spacetime dimensions, there exist duality proposals linking higher spin gravity theories to specific conformal field theories living in two and three dimensions respectively. The enlarged symmetry algebra of the conformal field theories renders them exactly soluble, which makes them excellent laboratories for understanding in detail the holographic mechanism behind AdS/CFT duality. Steady progress is also being made on better understanding the space of possible higher spin gravity theories and their physical content. This work includes classifying the possible field multiplets and their interactions, constructing exact solutions of the nonlinear field equations, and relating higher spin theories to string theory. A full understanding of these theories will involve coming to grips with the novel symmetry principles that enlarge those of General Relativity and Yang-Mills theory, and one can hope that this will provide

  3. Competitiveness - higher education

    Directory of Open Access Journals (Sweden)

    Labas Istvan

    2016-03-01

    Full Text Available Involvement of European Union plays an important role in the areas of education and training equally. The member states are responsible for organizing and operating their education and training systems themselves. And, EU policy is aimed at supporting the efforts of member states and trying to find solutions for the common challenges which appear. In order to make our future sustainable maximally; the key to it lies in education. The highly qualified workforce is the key to development, advancement and innovation of the world. Nowadays, the competitiveness of higher education institutions has become more and more appreciated in the national economy. In recent years, the frameworks of operation of higher education systems have gone through a total transformation. The number of applying students is continuously decreasing in some European countries therefore only those institutions can “survive” this shortfall, which are able to minimize the loss of the number of students. In this process, the factors forming the competitiveness of these budgetary institutions play an important role from the point of view of survival. The more competitive a higher education institution is, the greater the chance is that the students would like to continue their studies there and thus this institution will have a greater chance for the survival in the future, compared to ones lagging behind in the competition. Aim of our treatise prepared is to present the current situation and main data of the EU higher education and we examine the performance of higher education: to what extent it fulfils the strategy for smart, sustainable and inclusive growth which is worded in the framework of Europe 2020 programme. The treatise is based on analysis of statistical data.

  4. Porous carbons

    Indian Academy of Sciences (India)

    Carbon in dense as well as porous solid form is used in a variety of applications. Activated porous carbons are made through pyrolysis and activation of carbonaceous natural as well as synthetic precursors. Pyrolysed woods replicate the structure of original wood but as such possess very low surface areas and poor ...

  5. Evidence for Calcium Carbonate at the Phoenix Landing Site

    Science.gov (United States)

    Boynton, W. V.; Ming, D. W.; Sutter, B.; Arvidson, R. E.; Hoffman, J.; Niles, P. B.; Smith, P.

    2009-01-01

    The Phoenix mission has recently finished its study of the north polar environment of Mars with the aim to help understand both the current climate and to put constraints on past climate. An important part of understanding the past climate is the study of secondary minerals, those formed by reaction with volatile compounds such as H2O and CO2. This work describes observations made by the Thermal and Evolved-Gas Analyzer (TEGA) on the Phoenix Lander related to carbonate minerals. Carbonates are generally considered to be products of aqueous processes. A wet and warmer climate during the early history of Mars coupled with a much denser CO2 atmosphere are ideal conditions for the aqueous alteration of basaltic materials and the subsequent formation of carbonates. Carbonates (Mg- and Ca-rich) are predicted to be thermodynamically stable minerals in the present martian environment, however, there have been only a few indications of carbonates on the surface by a host of orbiting and landed missions to Mars. Carbonates (Mg-rich) have been suggested to be a component (2-5 wt %) of the martian global dust based upon orbital thermal emission spectroscopy. The identifications, based on the presence of a 1480 cm-1 absorption feature, are consistent with Mgcarbonates. A similar feature is observed in brighter, undisturbed soils by Mini-TES on the Gusev plains. Recently, Mg-rich carbonates have been identified in the Nili Fossae region by the CRISM instrument onboard the Mars Reconnaissance Orbiter. Carbonates have also been confirmed as aqueous alteration phases in martian meteorites so it is puzzling why there have not been more discoveries of carbonates by landers, rovers, and orbiters. Carbonates may hold important clues about the history of liquid water and aqueous processes on the surface of Mars.

  6. Chiral higher spin gravity

    Science.gov (United States)

    Krishnan, Chethan; Raju, Avinash

    2017-06-01

    We construct a candidate for the most general chiral higher spin theory with AdS3 boundary conditions. In the Chern-Simons language, on the left it has the Drinfeld-Sokolov reduced form, but on the right all charges and chemical potentials are turned on. Altogether (for the spin-3 case) these are 19 functions. Despite this, we show that the resulting metric has the form of the "most general" AdS3 boundary conditions discussed by Grumiller and Riegler. The asymptotic symmetry algebra is a product of a W3 algebra on the left and an affine s l (3 )k current algebra on the right, as desired. The metric and higher spin fields depend on all the 19 functions. We compare our work with previous results in the literature.

  7. Gamification in higher education

    OpenAIRE

    Langendahl, Per-Anders; Cook, Matthew; Mark-Herbert, Cecilia

    2016-01-01

    This report explores gamification as a pedagogic approach to engage and motivate students in higher education. Gamification is understood here to be the use of game elements in non-game contexts. Here game elements correspond to the characteristics of games, and context is defined as the activity and setting gamified. Gamification is deployed in various contexts such as running, shopping and learning and is therefore an open and multifaceted concept with multiple applications. The report deve...

  8. Carbon, Nitrogen, and Water Response to Land Use and Management Decisions under a Changing Climate in Pennsylvania during the 21st Century

    Science.gov (United States)

    Felzer, B. S.; Kicklighter, D. W.

    2011-12-01

    The effects of future climate change and increases in atmospheric CO2 levels in Pennsylvania must be considered in the context of land use and management decisions. While Pennsylvania was originally completely forested at the outset of the colonial period, 19th century land clearing and subsequent regrowth has changed the forest cover of Pennsylvania from 32% to 64% of the land area. Recent trends from 1992-2005 show that developed land has increased by 131% at the expense of agricultural land and forests. Future climate projections indicate that Pennsylvania will get significantly warmer and wetter due to continued increases in greenhouse gases. Using the Terrestrial Ecosystem Model version Hydro (TEM-Hydro), this study explores the role of land use and management in carbon and water dynamics during the 20th century and for four land use scenarios in the 21st century including: 1) a potential vegetation land cover of 100% forest; 2) a current land cover comprising mature forests, crops, pasture, and developed area; 3) a current land cover with younger forests; and 4) a future land cover scenario based on expanding development at the rate of 639,284 acres per decade adjacent to existing developed lands. Common assumptions are made about land use management, but we also explore the effect of crop tilling. TEM-Hydro runs are forced by 20th century climate from the PRISM model and 21st century climate from the NCAR CCSM3.0 IPCC A2 and B1 scenarios downscaled and bias corrected to 1/8o resolution. Regrowing forests are the only ecosystem with positive Net Carbon Exchange (NCE, Net Ecosystem Productivity minus carbon losses from the conversion of natural vegetation to cultivation and decomposition of agricultural and wood products, where positive indicates ecosystem sink), and sequester about 11,000 g C m-2 over the 20th century. The highest rates of leaching of dissolved inorganic nitrogen (DIN) occur in those areas that are fertilized, which include urban turf lawns

  9. Carbon Nanotubes for Supercapacitor

    Science.gov (United States)

    2010-01-01

    As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs) and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage. PMID:20672061

  10. Carbon Nanotubes for Supercapacitor

    Directory of Open Access Journals (Sweden)

    Li Jianyi

    2010-01-01

    Full Text Available Abstract As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage.

  11. Carbon nanotubes for supercapacitor.

    Science.gov (United States)

    Pan, Hui; Li, Jianyi; Feng, Yuanping

    2010-01-05

    As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs) and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage.

  12. Higher Education in Scandinavia

    DEFF Research Database (Denmark)

    Nielsen, Jørgen Lerche; Andreasen, Lars Birch

    2015-01-01

    Higher education systems around the world have been undergoing fundamental changes through the last 50 years from more narrow self-sustaining universities for the elite and into mass universities, where new groups of students have been recruited and the number of students enrolled has increased...... dramatically. In adjusting to the role of being a mass educational institution, universities have been challenged on how to cope with external pressures, such as forces of globalization and international markets, increased national and international competition for students and research grants, increased...... an impact on the educational systems in Scandinavia, and what possible futures can be envisioned?...

  13. Higher engineering mathematics

    CERN Document Server

    John Bird

    2014-01-01

    A practical introduction to the core mathematics principles required at higher engineering levelJohn Bird's approach to mathematics, based on numerous worked examples and interactive problems, is ideal for vocational students that require an advanced textbook.Theory is kept to a minimum, with the emphasis firmly placed on problem-solving skills, making this a thoroughly practical introduction to the advanced mathematics engineering that students need to master. The extensive and thorough topic coverage makes this an ideal text for upper level vocational courses. Now in

  14. The Impact of Climate Change on Microbial Communities and Carbon Cycling in High Arctic Permafrost Soil from Spitsbergen, Northern Norway

    Science.gov (United States)

    de Leon, K. C.; Schwery, D.; Yoshikawa, K.; Christiansen, H. H.; Pearce, D.

    2014-12-01

    Permafrost-affected soils are among the most fragile ecosystems in which current microbial controls on organic matter decomposition are changing as a result of climate change. Warmer conditions in the high Arctic will lead to a deepening of the seasonal active layer of permafrost, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. The viable and non-viable fractions of the microbial community in a permafrost soil from Adventdalen, Spitsbergen, Norway were subjected to a comprehensive investigation using culture-dependent and culture-independent methods. Molecular analyses using FISH (with CTC-DAPI) and amplified rDNA restriction analysis (ARDRA) on a 257cm deep core, revealed the presence of all major microbial soil groups, with the active layer having more viable cells, and a higher microbial community diversity. Carbon dioxide (CO2) and methane (CH4) flux measurements were performed to show the amount of C stored in the sample. We demonstrated that the microbial community composition from the soil in the center of the core was most likely influenced by small scale variations in environmental conditions. Community structure showed distinct shift of presence of bacterial groups along the vertical temperature gradient profile and microbial counts and diversity was found to be highest in the surface layers, decreasing with depth. It was observed that soil properties driving microbial diversity and functional potential varied across the permafrost table. Data on the variability of CO2 and CH4 distribution described in peat structure heterogeneity are important for modeling emissions on a larger scale. Furthermore, linking microbial biomass to gas distribution may elucidate the cause of peak CO2 and CH4 and their changes in relation to environmental change and peat composition.

  15. Towards higher intensities

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Over the past 2 weeks, commissioning of the machine protection system has advanced significantly, opening up the possibility of higher intensity collisions at 3.5 TeV. The intensity has been increased from 2 bunches of 1010 protons to 6 bunches of 2x1010 protons. Luminosities of 6x1028 cm-2s-1 have been achieved at the start of fills, a factor of 60 higher than those provided for the first collisions on 30 March.   The recent increase in LHC luminosity as recorded by the experiments. (Graph courtesy of the experiments and M. Ferro-Luzzi) To increase the luminosity further, the commissioning crews are now trying to push up the intensity of the individual proton bunches. After the successful injection of nominal intensity bunches containing 1.1x1011 protons, collisions were subsequently achieved at 450 GeV with these intensities. However, half-way through the first ramping of these nominal intensity bunches to 3.5 TeV on 15 May, a beam instability was observed, leading to partial beam loss...

  16. Carbon Stars

    Indian Academy of Sciences (India)

    Abstract. In this paper, the present state of knowledge of the carbon stars is discussed. Particular attention is given to issues of classification, evolution, variability, populations in our own and other galaxies, and circumstellar material.

  17. Developments in carbon materials

    Science.gov (United States)

    Burchell, Timothy D.

    1994-01-01

    The following carbon-based materials are reviewed and their applications discussed: fullerenes; graphite (synthetic and manufactured); activated carbon fibers; and carbon-carbon composites. Carbon R&D activities at ORNL are emphasized.

  18. Teaching at higher levels

    Science.gov (United States)

    1998-11-01

    Undergraduate physics programmes for the 21st century were under discussion at a recent event held in Arlington, USA, open to two or three members of the physics faculties of universities from across the whole country. The conference was organized by the American Association of Physics Teachers with co-sponsorship from the American Institute of Physics, the American Physical Society and Project Kaleidoscope. Among the various aims were to learn about physics departments that have successfully revitalized their undergraduate physics programmes with innovative introductory physics courses and multi-track majors programmes. Engineers and life scientists were to be asked directly how physics programmes can better serve their students, and business leaders would be speaking on how physics departments can help to prepare their students for the diverse careers that they will eventually follow. It was planned to highlight ways that departments could fulfil their responsibilities towards trainee teachers, to identify the resources needed for revitalizing a department's programme, and to develop guidelines and recommendations for a funding programme to support collaborative efforts among physics departments for carrying out the enhancements required. More details about the conference can be found on the AAPT website (see http://www.aapt.org/programs/rupc.html). Meanwhile the UK's Higher Education Funding Council has proposed a two-pronged approach to the promotion of high quality teaching and learning, as well as widening participation in higher education from 1999-2000. A total of £60m should be available to support these initiatives by the year 2001-2002. As part of this scheme the Council will invite bids from institutions to support individual academics in enhancing learning and teaching, as well as in recognition of individual excellence. As with research grants, such awards would enable staff to pursue activities such as the development of teaching materials

  19. Manufacturing of Nanocomposite Carbon Fibers and Composite Cylinders

    Science.gov (United States)

    Tan, Seng; Zhou, Jian-guo

    2013-01-01

    Pitch-based nanocomposite carbon fibers were prepared with various percentages of carbon nanofibers (CNFs), and the fibers were used for manufacturing composite structures. Experimental results show that these nanocomposite carbon fibers exhibit improved structural and electrical conductivity properties as compared to unreinforced carbon fibers. Composite panels fabricated from these nanocomposite carbon fibers and an epoxy system also show the same properties transformed from the fibers. Single-fiber testing per ASTM C1557 standard indicates that the nanocomposite carbon fiber has a tensile modulus of 110% higher, and a tensile strength 17.7% times higher, than the conventional carbon fiber manufactured from pitch. Also, the electrical resistance of the carbon fiber carbonized at 900 C was reduced from 4.8 to 2.2 ohm/cm. The manufacturing of the nanocomposite carbon fiber was based on an extrusion, non-solvent process. The precursor fibers were then carbonized and graphitized. The resultant fibers are continuous.

  20. Higher Order Mode Fibers

    DEFF Research Database (Denmark)

    Israelsen, Stine Møller

    This PhD thesis considers higher order modes (HOMs) in optical fibers. That includes their excitation and characteristics. Within the last decades, HOMs have been applied both for space multiplexing in optical communications, group velocity dispersion management and sensing among others....... The research presented in this thesis falls in three parts. In the first part, a first time demonstration of the break of the azimuthal symmetry of the Bessel-like LP0X modes is presented. This effect, known as the bowtie effect, causes the mode to have an azimuthal dependence as well as a quasi......-radial polarization as opposed to the linear polarization of the LP0X modes. The effect is investigated numerically in a double cladding fiber with an outer aircladding using a full vectorial modesolver. Experimentally, the bowtie modes are excited using a long period grating and their free space characteristics...

  1. The Political Economy of Carbon Securities and Environmental Policy

    DEFF Research Database (Denmark)

    Polborn, Sarah

    The costs of the current suboptimal carbon abatement policy are likely in the range of 3 to 6 trillion 2005 US dollars. Using methods from the political economy of environmental policy, the paper develops a new carbon abatement policy instrument, carbon securities. A carbon security entitles its...... environmental policy, and higher investment in abatement technology....

  2. Infiltrated carbon foam composites

    Science.gov (United States)

    Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)

    2012-01-01

    An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.

  3. The Vibration of a Linear Carbon Chain in Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Dongqing Ding

    2017-04-01

    Full Text Available An explicit solution for the vibration of a carbon chain inside carbon nanotubes (CNTs was obtained using continuum modeling of the van der Waals (vdW interactions between them. The effect of the initial tensile force and the amplitude of the carbon chain as well as the radii of the CNTs on the vibration frequency were analyzed in detail, respectively. Our analytical results show that the vibration frequency of the carbon chain in a (5,5 CNT could be around two orders of magnitude higher than that of an independent carbon chain without initial tensile force. For a given CNT radius, the vibration frequency nonlinearly increases with increasing amplitude and initial tensile force. The obtained analytical cohesive energy and vibration frequency are reasonable by comparison of present molecular dynamics (MD simulations. These findings will be a great help towards understanding the vibration property of a nanowire in nanotubes, and designing nanoelectromechanical devices.

  4. Learning higher mathematics

    CERN Document Server

    Pontrjagin, Lev Semenovič

    1984-01-01

    Lev Semenovic Pontrjagin (1908) is one of the outstanding figures in 20th century mathematics. In a long career he has made fundamental con­ tributions to many branches of mathematics, both pure and applied. He has received every honor that a grateful government can bestow. Though in no way constrained to do so, he has through the years taught mathematics courses at Moscow State University. In the year 1975 he set himself the task of writing a series of books on secondary school and beginning university mathematics. In his own words, "I wished to set forth the foundations of higher mathematics in a form that would have been accessible to myself as a lad, but making use of all my experience as a scientist and a teacher, ac­ cumulated over many years. " The present volume is a translation of the first two out of four moderately sized volumes on this theme planned by Pro­ fessor Pontrjagin. The book begins at the beginning of modern mathematics, analytic ge­ ometry in the plane and 3-dimensional space. Refin...

  5. Carbon Nanotubes for Supercapacitor

    OpenAIRE

    Li Jianyi; Pan Hui; Feng YuanPing

    2010-01-01

    Abstract As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs) and their composites. The purpose is to give a comprehensive understanding of the advantages and disad...

  6. Brominated graphitized carbon fibers

    Science.gov (United States)

    Hung, Ching-Cheh (Inventor)

    1991-01-01

    Low cost, high break elongation graphitized carbon fibers having low degree of graphitization are inert to bromine at room or higher temperatures, but are brominated at -7 to 20 C, and then debrominated at ambient. Repetition of this bromination-debromination process can bring the bromine content to 18 percent. Electrical conductivity of the brominated fibers is three times of the before-bromination value.

  7. Gender specific patterns of carbon uptake and water use in a dominant riparian tree species exposed to a warming climate.

    Science.gov (United States)

    Hultine, Kevin R; Burtch, Kelley G; Ehleringer, James R

    2013-11-01

    Air temperatures in the arid western United States are predicted to increase over the next century. These increases will likely impact the distribution of plant species, particularly dioecious species that show a spatial segregation of the sexes across broad resource gradients. On the basis of spatial segregation patterns, we hypothesized that temperature increases will have a greater negative impact on female plants compared with co-occurring male plants of dioecious species. This hypothesis was tested by examining the whole-plant carbon and water relations of 10-year-old female (n = 18) and male (n = 13) Acer negundo Sarg. trees grown in a common garden in Salt Lake City, UT. The trees were established from cuttings collected where the growing season temperature averaged about 6.5 °C cooler than at the common garden. During May and June, stem sap flux (Js ) was similar between genders, but averaged 25% higher in males during the warmer months of July and August. Daytime canopy stomatal conductance (gs ) per unit leaf area was 12% higher in females in May : June, but was 11% higher in males in July : August. We combined measurements of sap flux-scaled transpiration with measurements of tree allometry and δ(13) C of leaf soluble sugars to estimate whole-tree carbon assimilation (Atree ) and water use efficiency (WUE) (Atree  : Etree ). Atree was similar between genders until late August when Atree was 32% higher in male trees. Atree  : Etree was on average 7% higher in females than in males during the growing season. Patterns of Js , gs , Atree and Atree  : Etree in the present study were in contrast to those previously reported for A. negundo genders under native growing season temperatures. Results suggest that the spatial segregation of the sexes could shift under global warming such that female plants lose their dominance in high-resource habitats, and males increase their dominance in relatively lower-resource habitats. © 2013 John Wiley

  8. Esterification of glycerol from biodiesel production to glycerol carbonate in non-catalytic supercritical dimethyl carbonate.

    Science.gov (United States)

    Ilham, Zul; Saka, Shiro

    2016-01-01

    Conversion of glycerol from biodiesel production to glycerol carbonate was studied by esterification with dimethyl carbonate in a non-catalytic supercritical condition. It was found that in a non-catalytic supercritical condition, glycerol at higher purity gave higher yield of glycerol carbonate at 98 wt% after reaction at 300 °C/20-40 MPa/15 min. The yield of glycerol carbonate was observed to increase with molar ratio, temperature, pressure and time until a certain equilibrium limit. The existence of impurities such as water and remnants of alkaline catalyst in crude glycerol will direct the reaction to produce glycidol. Although impurities might not be desirable, the non-catalytic supercritical dimethyl carbonate could be an alternative method for conversion of glycerol from biodiesel production to value-added glycerol carbonate.Graphical abstractPlausible reaction scheme for conversion of glycerol to glycerol carbonate in non-catalytic supercritical dimethyl carbonate.

  9. Carbon Mineralization and Nitrogen Transformation During a Long Term Permafrost Incubation

    Science.gov (United States)

    Salmon, V. G.; Mack, M. C.; Schuur, E. A. G.

    2014-12-01

    As the limiting nutrient in warming high latitude ecosystems, nitrogen (N) is expected to play a key role in determining the future balance between permafrost carbon (C) losses and increased C sequestration by plants. During decomposition, nitrogen previously locked in soil organic matter is released into the soil solution in the form of dissolved organic molecules following depolymerization by extracellular enzymes. These dissolved organic forms of N can be consumed by the soil microbial community and incorporated in their biomass or mineralized if they are in excess of microbial demand. Once mineralized and released into the soil solutions, N can be lost from the soil system via denitrification. In well drained, low N tussock tundra, however, this pathway is unlikely. Dissolved inorganic N (DIN) and dissolved organic N (DON) are both biologically available to arctic plants. Understanding how the size of these pools changes with depth and continuing decomposition is therefore crucial to projecting the C balance of high latitude systems in a warmer future. N transformations associated with decomposition may differ greatly in surface soils, where a large labile C pool is present and soil has a high C:N ratio, versus deep soils that have a relatively small labile C pool and a lower C:N ratio. In this experiment, the relationship between N availability and C release from permafrost soils was addressed with a 225 day soil incubation performed at 15°C. Seven soil cores were collected from undisturbed, well drained tussock tundra and were partitioned into ten centimeter depth intervals to a depth of 80 cm. Carbon dioxide (CO2) fluxes were measured throughout the incubation period and were used to assess cumulative carbon losses and determine the size of the labile C pool. Destructive harvests at days 16,34,55,83, 143 and 225 were performed and pools of plant available DON and DIN were measured using 2M KCl extractions. At day 225 the microbial biomass N pool was also

  10. Observational constraints on mixed-phase clouds imply higher climate sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Tan, I.; Storelvmo, T.; Zelinka, M. D.

    2016-04-07

    Global climate model (GCM) estimates of the equilibrium global mean surface temperature response to a doubling of atmospheric CO2, measured by the equilibrium climate sensitivity (ECS), range from 2.0° to 4.6°C. Clouds are among the leading causes of this uncertainty. Here we show that the ECS can be up to 1.3°C higher in simulations where mixed-phase clouds consisting of ice crystals and supercooled liquid droplets are constrained by global satellite observations. The higher ECS estimates are directly linked to a weakened cloud-phase feedback arising from a decreased cloud glaciation rate in a warmer climate. We point out the need for realistic representations of the supercooled liquid fraction in mixed-phase clouds in GCMs, given the sensitivity of the ECS to the cloud-phase feedback.

  11. Potential host number in cuckoo bees (Psithyrus subgen. increases toward higher elevations

    Directory of Open Access Journals (Sweden)

    Jean-Nicolas Pradervand

    2013-07-01

    Full Text Available In severe and variable conditions, specialized resource selection strategies should be less frequent because extinction risks increase for species that depend on a single and unstable resource. Psithyrus (Bombus subgenus Psithyrus are bumblebee parasites that usurp Bombus nests and display inter‐specific variation in the number of hosts they parasitize. Using a phylogenetic comparative framework, we show that Psithyrus species at higher elevations display a higher number of hosts species compared with species restricted to lower elevations. Species inhabiting high elevations also cover a larger temperature range, suggesting that species able to occur in colder conditions may benefit from recruitment from populations occurring in warmer conditions. Our results provide evidence for an ‘altitudinal niche breadth hypothesis’ in parasitic species, showing a decrease in the parasites’ specialization along the elevational gradient, and also suggesting that Rapoport’s rule might apply to Psithyrus. 

  12. Higher Efficiency HVAC Motors

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, Charles Joseph

    2018-02-13

    failure prone capacitors from the power stage. Q-Sync’s simpler electronics also result in higher efficiency because it eliminates the power required by the PCB to perform the obviated power conversions and PWM processes after line synchronous operating speed is reached in the first 5 seconds of operation, after which the PWM circuits drop out and a much less energy intensive “pass through” circuit takes over, allowing the grid-supplied AC power to sustain the motor’s ongoing operation.

  13. Marine meiofauna, carbon and nitrogen mineralization in sandy and soft sediments of Disko Bay, West Greenland

    DEFF Research Database (Denmark)

    Rysgaard, S.; Christensen, P.B.; Sørensen, Martin Vinther

    2000-01-01

    layers of the sediment. Algal photosynthetic activity and nitrogen uptake reduced nitrogen effluxes and denitrification rates. Sulfate reduction was the most important pathway for carbon mineralization in the sediments of the shallow-water station. In contrast, high bottom-water NO3- concentrations...... and was, together with organotrophic O-2 respiration, the most important pathway for carbon mineralization within these sediments. The obtained process rates were comparable to mineralization rates from much warmer localities, suggesting that benthic mineralization in arctic marine environments......Organic carbon mineralization was studied in a shallow-water (4 m), sandy sediment and 2 comparatively deep-water (150 and 300 m), soft sediments in Disko Bay, West Greenland. Benthic microalgae inhabiting the shallow-water locality significantly affected diurnal O-2 conditions within the surface...

  14. Resistivity of Carbon-Carbon Composites Halved

    Science.gov (United States)

    Gaier, James R.

    2004-01-01

    Carbon-carbon composites have become the material of choice for applications requiring strength and stiffness at very high temperatures (above 2000 C). These composites comprise carbon or graphite fibers embedded in a carbonized or graphitized matrix. In some applications, such as shielding sensitive electronics in very high temperature environments, the performance of these materials would be improved by lowering their electrical resistivity. One method to lower the resistivity of the composites is to lower the resistivity of the graphite fibers, and a proven method to accomplish that is intercalation. Intercalation is the insertion of guest atoms or molecules into a host lattice. In this study the host fibers were highly graphitic pitch-based graphite fibers, or vapor-grown carbon fibers (VGCF), and the intercalate was bromine. Intercalation compounds of graphite are generally thought of as being only metastable, but it has been shown that the residual bromine graphite fiber intercalation compound is remarkably stable, resisting decomposition even at temperatures at least as high as 1000 C. The focus of this work was to fabricate composite preforms, determine whether the fibers they were made from were still intercalated with bromine after processing, and determine the effect on composite resistivity. It was not expected that the resistivity would be lowered as dramatically as with graphite polymer composites because the matrix itself would be much more conductive, but it was hoped that the gains would be substantial enough to warrant its use in high-performance applications. In a collaborative effort supporting a Space Act Agreement between the NASA Glenn Research Center and Applied Sciences, Inc. (Cedarville, OH), laminar preforms were fabricated with pristine and bromine-intercalated pitch-based fibers (P100 and P100-Br) and VGCF (Pyro I and Pyro I-Br). The green preforms were carbonized at 1000 C and then heat treated to 3000 C. To determine whether the

  15. Increasing carbon discrimination rates and depth of water uptake favor the growth of Mediterranean evergreen trees in the ecotone with temperate deciduous forests.

    Science.gov (United States)

    Barbeta, Adrià; Peñuelas, Josep

    2017-12-01

    Tree populations at the low-altitudinal or -latitudinal limits of species' distributional ranges are predicted to retreat toward higher altitudes and latitudes to track the ongoing changes in climate. Studies have focused on the climatic sensitivity of the retreating species, whereas little is known about the potential replacements. Competition between tree species in forest ecotones will likely be strongly influenced by the ecophysiological responses to heat and drought. We used tree-ring widths and δ13 C and δ18 O chronologies to compare the growth rates and long-term ecophysiological responses to climate in the temperate-Mediterranean ecotone formed by the deciduous Fagus sylvatica and the evergreen Quercus ilex at the low altitudinal and southern latitudinal limit of F. sylvatica (NE Iberian Peninsula). F. sylvatica growth rates were similar to those of other southern populations and were surprisingly not higher than those of Q. ilex, which were an order of magnitude higher than those in nearby drier sites. Higher Q. ilex growth rates were associated with high temperatures, which have increased carbon discrimination rates in the last 25 years. In contrast, stomatal regulation in F. sylvatica was proportional to the increase in atmospheric CO2 . Tree-ring δ18 O for both species were mostly correlated with δ18 O in the source water. In contrast to many previous studies, relative humidity was not negatively correlated with tree-ring δ18 O but had a positive effect on Q. ilex tree-ring δ18 O. Furthermore, tree-ring δ18 O decreased in Q. ilex over time. The sensitivity of Q. ilex to climate likely reflects the uptake of deep water that allowed it to benefit from the effect of CO2 fertilization, in contrast to the water-limited F. sylvatica. Consequently, Q. ilex is a strong competitor at sites currently dominated by F. sylvatica and could be favored by increasingly warmer conditions. © 2017 John Wiley & Sons Ltd.

  16. Ternary carbon composite films for supercapacitor applications

    Science.gov (United States)

    Tran, Minh-Hai; Jeong, Hae Kyung

    2017-09-01

    A simple, binder-free, method of making supercapacitor electrodes is introduced, based on modification of activated carbon with graphite oxide and carbon nanotubes. The three carbon precursors of different morphologies support each other to provide outstanding electrochemical performance, such as high capacitance and high energy density. The ternary carbon composite shows six times higher specific capacitance compared to that of activated carbon itself with high retention. The excellent electrochemical properties of the ternary composite attribute to the high surface area of 1933 m2 g-1 and low equivalent series resistance of 2 Ω, demonstrating that it improve the electrochemical performance for supercapacitor applications.

  17. Carbon classified?

    DEFF Research Database (Denmark)

    Lippert, Ingmar

    2012-01-01

    . Using an actor- network theory (ANT) framework, the aim is to investigate the actors who bring together the elements needed to classify their carbon emission sources and unpack the heterogeneous relations drawn on. Based on an ethnographic study of corporate agents of ecological modernisation over...... and corporations construing themselves as able and suitable to manage their emissions, and, additionally, given that the construction of carbon emissions has performative consequences, the underlying practices need to be declassified, i.e. opened for public scrutiny. Hence the paper concludes by arguing...

  18. Performance Enhancement of Carbon Nanomaterials for Supercapacitors

    Directory of Open Access Journals (Sweden)

    Amin M. Saleem

    2016-01-01

    Full Text Available Carbon nanomaterials such as carbon nanotubes, carbon nanofibers, and graphene are exploited extensively due to their unique electrical, mechanical, and thermal properties and recently investigated for energy storage application (supercapacitor due to additional high specific surface area and chemical inertness properties. The supercapacitor is an energy storage device which, in addition to long cycle life (one million, can give energy density higher than parallel plate capacitor and power density higher than battery. In this paper, carbon nanomaterials and their composites are reviewed for prospective use as electrodes for supercapacitor. Moreover, different physical and chemical treatments on these nanomaterials which can potentially enhance the capacitance are also reviewed.

  19. The annual carbon budget for fen and forest in a wetland at Arctic treeline

    Energy Technology Data Exchange (ETDEWEB)

    Rouse, W. R. [McMaster Univ., School of Geography and Geology, Hamilton, ON (Canada); Bello, R. L.; D' Souza, A. [York Univ., Dept. of Geography, Toronto, ON (Canada); Griffis, T. J. [Minnesota Univ., Dept. of Soil, Water and Climate, St. Paul, MN (United States); LaFleur, P. M. [Trent Univ., Dept. of Geography, Peterborough, ON (Canada)

    2002-09-01

    This study of a wetland system at the Arctic treeline compares two carbon budget estimates, one derived from long-term growth rates of organic soil and the other based on shorter-term flux measurements. Result showed that while there was a small loss of carbon from the ecosystem in the case of tundra fen over a period of fifty-three years, the adjacent open subarctic forest showed large gains in atmospheric carbon dioxide during the same period. These longer-term data were supported by shorter-term flux measurements, which also showed carbon loss by the fen and carbon uptake by the forest. The shorter term data indicate that the carbon loss from the fen during this period was attributable to one particularly dry year. The different rates of carbon exchange appear to be controlled by two primary factors. The first is the enhanced development in the fen of a photosynthesis-inhibiting hummock-hollow landscape, while the second is related to warmer and drier average growing season conditions, which inhibit carbon dioxide uptake in the fen and enhances it in the forest. 24 refs., 4 tabs., 3 figs.

  20. Epidemiology: Malaria in a warmer West Africa

    Science.gov (United States)

    Caminade, C.; Jones, A. E.

    2016-11-01

    Malaria risk in West Africa is expected to fall (western region) or remain the same (eastern region) in response to climate change over the twenty-first century. This is primarily due to extreme temperature conditions projected under a high greenhouse gas emissions scenario.

  1. Carbon nanotube solar cells.

    Directory of Open Access Journals (Sweden)

    Colin Klinger

    Full Text Available We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabricate using a spray-paint technique. We observe that cells with a lower concentration of carbon nanotubes on the active semiconducting electrode perform better than cells with a higher concentration of nanotubes. This effect is contrary to the expectation that a larger number of nanotubes would lead to more photoconversion and therefore more power generation. We attribute this to the presence of metallic nanotubes that provide a short for photo-excited electrons, bypassing the load. We demonstrate optimization strategies that improve cell efficiency by orders of magnitude. Once it is possible to make semiconducting-only carbon nanotube films, that may provide the greatest efficiency improvement.

  2. Carbon-carbon - An overview

    Science.gov (United States)

    Buckley, John D.

    1988-01-01

    In nonoxidizing high-temperature environments, carbon-carbon composites retain room temperature properties to more than 2225 C; in oxidizing environments, the variety of coatings thus far developed limits maximum operating temperatures to about 1600 C. The high thermal conductivity and low thermal expansion of these composites renders them ideal for applications encountering thermal shocks. In addition, the variety of fibers, weave patterns, and layup procedures that can be used for the composites allows mechanical properties to be carefully tailored over a wide range to fit the application in question.

  3. Carbon Capture and Storage

    Energy Technology Data Exchange (ETDEWEB)

    Friedmann, S

    2007-10-03

    key documents written in the last three years that provide information on the status, economics, technology, and impact of CCS. These are cited throughout this text and identified as key references at the end of this manuscript. When coupled with improvements in energy efficiency, renewable energy supplies, and nuclear power, CCS help dramatically reduce current and future emissions (US CCTP 2005, MIT 2007). If CCS is not available as a carbon management option, it will be much more difficult and much more expensive to stabilize atmospheric CO{sub 2} emissions. Recent estimates put the cost of carbon abatement without CCS to be 30-80% higher that if CCS were to be available (Edmonds et al. 2004).

  4. A hypothesis and a case-study projection of an influence of MJO modulation on boreal-summer tropical cyclogenesis in a warmer climate with a global non-hydrostatic model: a transition toward the central Pacific?

    Directory of Open Access Journals (Sweden)

    KAZUYOSHI eOOUCHI

    2014-02-01

    Full Text Available The eastward shift of the enhanced activity of tropical cyclone to the central Pacific is a robust projection result for a future warmer climate, and is shared by most of the state-of-the-art climate models. The shift has been argued to originate from the underlying El-Ñino like sea-surface temperature (SST forcing. This study explores the possibility that the change of the activity of the Madden-Julian Oscillation (MJO can be an additional, if not alternative, contributor to the shift, using the dataset of Yamada et al. (2010 from a global non-hydrostatic 14-km grid mesh time-slice experiment for a boreal-summer case. Within the case-study framework, we develop the hypothesis that an eastward shift of the high-activity area of the MJO, as manifested itself as the significant intra-seasonal modulation of the enhanced precipitation, is associated with the increased tropical cyclogenesis potential over the North central Pacific by regulating cyclonic relative vorticity and vertical shear. In contrast, the North Indian Ocean and maritime continent undergo relatively diminished genesis potential. An implication is that uncertainty in the future tropical cyclogenesis in some part of the Pacific and other ocean basins could be reduced if projection of the MJO and its connection with the underlying SST environment can be better understood and constrained by the improvement of climate models.

  5. The Degree of Permafrost Thawing Determines Arctic Tundra Carbon Balance

    Science.gov (United States)

    Vogel, J. G.; Schuur, E. A.; Sickman, J.; Lee, H.; Trucco, C.

    2007-12-01

    In interior Alaska, we measured gross photosynthesis (GP), ecosystem respiration (ER), and net ecosystem exchange (NEE) near a permafrost monitoring borehole that has recorded an increase in permafrost temperatures during the last 22 years. From May 2004 to May 2006, ecosystem C exchange measurements were made with static and automatic chambers in a moist acidic tundra ecosystem. A gradient in degree of permafrost thaw was used to select three sites (Minimal, Moderate and Severe Thaw) that corresponded to an increase in thermokarst occurrence. Between June 1 and August 30, the Severe and Moderate Thaw sites had significantly greater C uptake (GPP) (pproductivity. However, greater winter ER from the Severe Thaw site caused it to be a source (negative NEE, -128 g C m-2) of carbon over three years. The Moderate Thaw site was a carbon sink (52 g C m- 2), while the Minimal Thaw site was near carbon neutral (-7 g C m-2). In the spring and fall, carbon uptake correlated with the occurrence of plant functional groups (sedges, evergreen shrubs) that maintain green foliage and can photosynthesize under cold conditions. Both of these functional groups decreased inside thermokarst. In the winter, the Severe Thaw site lost 34% more C than the other two sites, likely due to warmer deep soil temperatures. As permafrost thaw proceeds, increasing ecosystem C loss may occur during the winter, spring, and fall due to the unique biotic and abiotic characteristics of thermokarst.

  6. Climate Warming Can Increase Soil Carbon Fluxes Without Decreasing Soil Carbon Stocks in Boreal Forests

    Science.gov (United States)

    Ziegler, S. E.; Benner, R. H.; Billings, S. A.; Edwards, K. A.; Philben, M. J.; Zhu, X.; Laganiere, J.

    2016-12-01

    Ecosystem C fluxes respond positively to climate warming, however, the net impact of changing C fluxes on soil organic carbon (SOC) stocks over decadal scales remains unclear. Manipulative studies and global-scale observations have informed much of the existing knowledge of SOC responses to climate, providing insights on relatively short (e.g. days to years) and long (centuries to millennia) time scales, respectively. Natural climate gradient studies capture integrated ecosystem responses to climate on decadal time scales. Here we report the soil C reservoirs, fluxes into and out of those reservoirs, and the chemical composition of inputs and soil organic matter pools along a mesic boreal forest climate transect. The sites studied consist of similar forest composition, successional stage, and soil moisture but differ by 5.2°C mean annual temperature. Carbon fluxes through these boreal forest soils were greatest in the lowest latitude regions and indicate that enhanced C inputs can offset soil C losses with warming in these forests. Respiration rates increased by 55% and the flux of dissolved organic carbon from the organic to mineral soil horizons tripled across this climate gradient. The 2-fold increase in litterfall inputs to these soils coincided with a significant increase in the organic horizon C stock with warming, however, no significant difference in the surface mineral soil C stocks was observed. The younger mean age of the mineral soil C ( 70 versus 330 YBP) provided further evidence for the greater turnover of SOC in the warmer climate soils. In spite of these differences in mean radiocarbon age, mineral SOC exhibited chemical characteristics of highly decomposed material across all regions. In contrast with depth trends in soil OM diagenetic indices, diagenetic shifts with latitude were limited to increases in C:N and alkyl to O-alkyl ratios in the overlying organic horizons in the warmer relative to the colder regions. These data indicate that the

  7. Carbon Based Refractories

    National Research Council Canada - National Science Library

    EWAIS, Emad Mohamed M

    2004-01-01

    .... They are classified into two groups; carbon/bricks/blocks and carbon containing materials. Carbon containing materials are further classified into carbon containing basic refractories and non-basic refractories...

  8. Carbon sequestration in the agroecosystem

    Directory of Open Access Journals (Sweden)

    Tomáš Středa

    2008-01-01

    Full Text Available Reduction of amount CO2 is possible by carbon sequestration to the soil. Fixation potential of EU–15 agricultural land is c. 16–19 mil t C . year−1. Amount and composition of post–harvest residues is essential for carbon soil sequestration. Long–term yield series of the most planted crops (winter wheat – Triticum aestivum, spring barley – Hordeum vulgare, corn and silage maize – Zea mays, winter rape – Brassica napus, potatoes – Solanum tuberosum, sugar beet – Beta vulgaris, alfalfa – Medicago sativa, red clover – Trifolium pratense, white mustard – Sinapis alba and fiddleneck – Phacelia tanacetifolia in various agroecological conditions and growing technologies were used for carbon balance calculation. The carbon balances were calculated for main crop rotations of maize, sugar beet, cereal and potato production regions (24 crop rotations. The calculations were realized for following planting varieties: traditional, commercial, ecological and with higher rate of winter rape. All chosen crop rotations (except seven have positive carbon balance in the tillage system. Amount of fixed carbon might be increases about 30% by the use of no–tillage system. Least amount of carbon is fixed by potatoes, high amount by cereals, alfalfa and sugar beet. For a short time (months the crops sequestration of carbon is relatively high (to 4.4 t . ha−1 . year−1 or to 5.7 t . ha−1 . year−1 for no–tillage system. From the long time viewpoint (tens of years the data of humified carbon in arable soil (max 400 kg C . ha−1 . year−1 are important. Maximal carbon deficit of chosen crop rotation is 725 kg C . year−1.

  9. Fabricating solid carbon porous electrodes from powders

    Science.gov (United States)

    Kaschmitter, J.L.; Tran, T.D.; Feikert, J.H.; Mayer, S.T.

    1997-06-10

    Fabrication is described for conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive deionization, and waste treatment. Electrodes fabricated from low surface area (graphite and cokes exhibit excellent reversible lithium intercalation characteristics, making them ideal for use as anodes in high voltage lithium insertion (lithium-ion) batteries. Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon composites with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to high surface area carbons, fuel cell electrodes can be produced. 1 fig.

  10. Carbon nanotubes

    OpenAIRE

    SLOBODAN N. MARINKOVIC

    2008-01-01

    Nanotubes, the last in the focus of scientists in a series of “all carbon” materials discovered over the last several decades are the most interesting and have the greatest potential. This review aims at presenting in a concise manner the considerable amount of knowledge accumulated since the discovery of this amazing form of solid carbon, particularly during the last 15 years. The topics include methods of synthesis, mathematical description, characterization by Raman spectroscopy, most impo...

  11. CarbonSat Constellation

    Science.gov (United States)

    Sun, Wei; Tobehn, Carsten; Ernst, Robert; Bovensmann, Heinrich; Buchwitz, Michael; Burrows, John P.; Notholt, John

    1 Carbon dioxide (CO2) and methane (CH4) are the most important manmade greenhouse gases (GHGs) which are driving global climate change. Currently, the CO2 measurements from the ground observing network are still the main sources of information but due to the limited number of measurement stations the coverage is limited. In addition, CO2 monitoring and trading is often based mainly on bottom-up calculations and an independent top down verification is limited due to the lack of global measurement data with local resolution. The first CO2 and CH4 mapping from SCIAMACHY on ENVISAT shows that satellites add important missing global information. Current GHG measurement satellites (GOSAT)are limited either in spatial or temporal resolution and coverage. These systems have to collect data over a year or even longer to produce global regional fluxes products. Conse-quently global, timely, higher spatial resolution and high accuracy measurement are required for: 1. A good understanding of the CO2 and CH4 sources and sinks for reliable climate predic-tion; and 2. Independent and transparent verification of accountable sources and sinks in supporting Kyoto and upcoming protocols The CarbonSat constellation idea comes out the trade off of resolution and swath width during CarbonSat mission definition studies. In response to the urgent need to support the Kyoto and upcoming protocols, a feasibility study has been carried out. The proposed solution is a constellation of five CarbonSat satellites in 614km LTAN 13:00, which is able to provide global, daily CO2 and CH4 measurement everywhere on the Earth with high spatial resolution 2 × 2 km and low uncertainty lt;2ppm (CO2) and lt;8ppb (CH4). The unique global daily measurement capability significantly increases the number of cloud free measurements, which enables more reliable services associated with reduced uncertainty, e.g. to 0.15ppm (CO2) per month in 10km and even more timely products. The CarbonSat Constellation in

  12. Are long-term trends in lake carbon dioxide flux responsive to climaticvariability and change?

    Science.gov (United States)

    Golub, M.; Desai, A. R.

    2012-12-01

    Inland water bodies are major but understudied conduits of carbon in within the global land-ocean-atmosphere carbon cycle. While many researchers have shown significant 20th century trends in physical and biological lake processes driven by climatic change, there is less research on how these influence lake-atmosphere carbon dioxide flux. We investigated the effects of climatic drivers on physical features and CO2 flux in lakes. We estimated the long-term trends in ice phenology, thermal structure, and amount of carbon exchanged, using 15-25-year time series of measurements of temperature, alkalinity, pH for eleven lakes monitored by the North Temperate Lakes Long-Term Ecological Research (NTL-LTER) program. Lakes coherently responded to regional climatic warming, showing declining ice cover duration, prolonged growing season, and increasingly warmer waters. Long-term trends of CO2 trends varied among lakes, however, with the majority of lakes showing a weakening source of CO2 to atmosphere. We further compared the sensitivity of CO2 flux to climate forcing in lakes as a function of trophic states, dissolved organic carbon concentrations, and morphometric features. These results provide new insights into our understanding about the role of lakes in regional and global carbon balances, on the sensitivity of CO2 flux to climatic variability, and in improving prediction of future carbon-climate change feedbacks.

  13. Urban Forests and Carbon Markets: Buyers’ Perspectives

    Science.gov (United States)

    Neelam C. Poudyal; Jacek Siry; J.M. Bowker

    2011-01-01

    Currently, carbon credit prices frequently do not reflect the type and location of offset projects. Because of the social image and ancillary benefits, buyers may place higher value on credits sourced from certain types of projects such as urban forestry. This study surveyed carbon credit buyers participating in the Chicago Climate Exchange to assess their preferences...

  14. Fluxes of Dissolved Organic Carbon within Soils across a Boreal Forest Ecosystem Latitudinal Transect

    Science.gov (United States)

    Bowering, K.; Edwards, K.; Billings, S. A.; Skinner, A.; Warren, J.; Ziegler, S. E.

    2013-12-01

    The movement of dissolved organic carbon (DOC) can represent a significant flux of C within soils, and may be a critical flux of C from the terrestrial into the aquatic environment. Further, these fluxes can represent an important source of C to deeper mineral horizons where stabilization mechanisms may exist. However the quantity and quality of this C flux is largely unknown, and regulating factors that are influenced by climate and land-use change are poorly understood. This movement of C is of particular interest in the boreal forest, where large soil C stocks are vulnerable to the impacts of climate change. Laboratory experiments have demonstrated that warming, in the absence of moisture limitation, can increase the rate of production of DOC in soils directly through increased decomposition rates; however, this has been difficult to test under field conditions where seasonality, intact soil, and hydrological systems influence DOC production and movement. To assess the impact of climate warming on DOC fluxes occurring through the organic soil layer of the eastern North American boreal forest, we sampled passive lysimeters installed at 3 sites along a latitudinal transect in Newfoundland and Labrador, Canada. Separated by just over 5° latitude, mean annual temperature at these sites were 4°C, 2.1°C, and -0.5°C from lowest to highest latitude. Six lysimeters were sampled from each site and collections were made at least three times annually for two consecutive years (2011-2013). Soils tend to freeze over-winter in the high-latitude site whereas they rarely freeze in the low-latitude site. The low-latitude site also experiences more variable precipitation, with a longer snow-free season and more precipitation falling during single events. Rates of DOC flux increased with decreasing latitude, indicating greater DOC transport through soils in forests experiencing a warmer climate. DOC fluxes calculated over different seasonal time periods ranged from 4.6 to 20

  15. Consequences of artic ground squirrels on soil carbon loss from Siberian tundra

    Science.gov (United States)

    Golden, N. A.; Natali, S.; Zimov, N.

    2014-12-01

    A large pool of organic carbon (C) has been accumulating in the Arctic for thousands of years. Much of this C has been frozen in permafrost and unavailable for microbial decomposition. As the climate warms and permafrost thaws, the fate of this large C pool will be driven not only by climatic conditions, but also by ecosystem changes brought about by arctic animal populations. In this project we studied arctic ground squirrels (Spermophilus parryii), which are widely-distributed throughout the Arctic. These social mammals create subterranean burrows that mix soil layers, increase aeration, alter soil moisture and temperature, and redistribute soil nutrients, all of which may impact microbial decomposition. We examined the effects of arctic ground squirrel activity on soil C mineralization in dry heath tundra underlain by continuous permafrost in the Kolyma River watershed in northeast Siberia, Russia. Vegetation cover was greatly reduced on the ground squirrel burrows (80% of ground un-vegetated), compared to undisturbed sites (35% of ground un-vegetated). Soils from ground squirrel burrows were also significantly dryer and warmer. To examine effects of ground squirrel activity on microbial respiration, we conducted an 8-day incubation of soil fromburrows and from adjacent undisturbed tundra. In addition, we assessed the impact of nutrient addition by including treatments with low and high levels of nitrogen addition. Microbial respiration (per gram soil) was three-fold higher in incubated soils from the undisturbed sites compared to soils collected from the burrows. The lower rates of respiration from the disturbed soils may have been a result of lower carbon quality or low soil moisture. High nitrogen addition significantly increased respiration in the undisturbed soils, but not in the disturbed burrow soils, which suggests that microbial respiration in the burrow soils was not primarily limited by nitrogen. These results demonstrate the importance of wildlife

  16. Suspended 3D pyrolytic carbon microelectrodes for electrochemistry

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Caviglia, Claudia; Keller, Stephan Sylvest

    2017-01-01

    Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. This work presents the fabrication and characterization of suspended pyrolytic carbon microstructures serving as three-dimensional (3D) carbon microelectrodes for electrochem...... resistance as compared to 2D carbon electrodes. The higher sensitivity of 3D carbon microelectrodes for electrochemical sensing was illustrated by dopamine detection.......Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. This work presents the fabrication and characterization of suspended pyrolytic carbon microstructures serving as three-dimensional (3D) carbon microelectrodes...... for electrochemical applications. A 3D polymer template in epoxy based photoresist (SU-8) was fabricated with multiple steps of UV photolithography and pyrolysed at 900 °C to obtain 3D carbon microelectrodes. The pyrolytic carbon microstructures were characterized by SEM, Raman spectroscopy and XPS to determine...

  17. Internationalization of Chinese Higher Education

    Science.gov (United States)

    Chen, Linhan; Huang, Danyan

    2013-01-01

    This paper probes into the development of internationalization of higher education in China from ancient times to modern times, including the emergence of international connections in Chinese higher education and the subsequent development of such connections, the further development of internationalization of Chinese higher education, and the…

  18. Higher Education Studies in Japan

    Science.gov (United States)

    Kaneko, Motohisa

    2010-01-01

    The rapid development of higher education in the postwar period has given rise to various problems, and higher education studies in Japan have developed in response to them. What have been the major issues, and how did academic research respond to them, in postwar Japan? This article delineates an outline of higher education studies in general,…

  19. Assessing the Impact of Model Parameter Uncertainty in Simulating Grass Biomass Using a Hybrid Carbon Allocation Strategy

    Science.gov (United States)

    Reyes, J. J.; Adam, J. C.; Tague, C.

    2016-12-01

    Grasslands play an important role in agricultural production as forage for livestock; they also provide a diverse set of ecosystem services including soil carbon (C) storage. The partitioning of C between above and belowground plant compartments (i.e. allocation) is influenced by both plant characteristics and environmental conditions. The objectives of this study are to 1) develop and evaluate a hybrid C allocation strategy suitable for grasslands, and 2) apply this strategy to examine the importance of various parameters related to biogeochemical cycling, photosynthesis, allocation, and soil water drainage on above and belowground biomass. We include allocation as an important process in quantifying the model parameter uncertainty, which identifies the most influential parameters and what processes may require further refinement. For this, we use the Regional Hydro-ecologic Simulation System, a mechanistic model that simulates coupled water and biogeochemical processes. A Latin hypercube sampling scheme was used to develop parameter sets for calibration and evaluation of allocation strategies, as well as parameter uncertainty analysis. We developed the hybrid allocation strategy to integrate both growth-based and resource-limited allocation mechanisms. When evaluating the new strategy simultaneously for above and belowground biomass, it produced a larger number of less biased parameter sets: 16% more compared to resource-limited and 9% more compared to growth-based. This also demonstrates its flexible application across diverse plant types and environmental conditions. We found that higher parameter importance corresponded to sub- or supra-optimal resource availability (i.e. water, nutrients) and temperature ranges (i.e. too hot or cold). For example, photosynthesis-related parameters were more important at sites warmer than the theoretical optimal growth temperature. Therefore, larger values of parameter importance indicate greater relative sensitivity in

  20. A Necessary Partnership: Study Abroad and Sustainability in Higher Education

    Science.gov (United States)

    Dvorak, Andrea M. W.; Christiansen, Lars D.; Fischer, Nancy L.; Underhill, Joseph B.

    2011-01-01

    The last two decades have seen institutions of higher education put increasing emphasis on both internationalizing their institutions and making them more sustainable. While laudable in their own right, there are contradictions and tensions between these goals, in particular when the carbon emissions involved in international activities like study…

  1. Spectroelectrochemistry of carbon nanostructures.

    Science.gov (United States)

    Kavan, Ladislav; Dunsch, Lothar

    2007-05-14

    This review is focused on charge-transfer reactions at carbon nanotubes and fullerenes. The spectroelectrochemistry of fullerenes deals with the spin states of fullerenes, the role of mono-anions and the reactivity of higher charged states in C60. The optical (Vis-NIR) spectroelectrochemistry of single-walled carbon nanotubes (SWNTs) follows changes in the allowed optical transitions among the Van Hove singularities. The Raman spectroelectrochemistry of SWNT benefits from strong resonance enhancement of the Raman scattering. Here, both semiconducting and metallic SWNTs are analyzed using the radial breathing mode (RBM) and G-modes as well as the second order (D, G') and intermediate frequency modes. Raman spectroelectrochemistry of SWNT allows the addressing of index-identified tubes and even single isolated nanotubes. Optical and Raman spectroelectrochemistry of fullerene peapods, C60@SWNT and C70@SWNT indicates effective shielding of the intratubular fullerene (peas). The most striking effect in the spectroelectrochemistry of peapods is the so-called "anodic Raman enhancement" of intratubular C60. Double-walled carbon nanotubes (DWNTs) give a specific spectroscopic response in Vis-NIR spectroelectrochemistry for the inner and the outer tube. They are better distinguishable by Raman spectroelectrochemistry which allows a precise tracing of the specific doping response of outer/inner tubes.

  2. Hydropower's Biogenic Carbon Footprint.

    Science.gov (United States)

    Scherer, Laura; Pfister, Stephan

    2016-01-01

    Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2.95 kg CH4 emitted per MWh of electricity produced. This results in a combined average carbon footprint of 273 kg CO2e/MWh when using the global warming potential over a time horizon of 100 years (GWP100). Nonetheless, this is still below that of fossil energy sources without the use of carbon capture and sequestration technologies. We identified the dams most promising for capturing methane for use as alternative energy source. The spread among the ~1500 hydropower plants analysed in this study is large and highlights the importance of case-by-case examinations.

  3. Hydropower's Biogenic Carbon Footprint.

    Directory of Open Access Journals (Sweden)

    Laura Scherer

    Full Text Available Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2.95 kg CH4 emitted per MWh of electricity produced. This results in a combined average carbon footprint of 273 kg CO2e/MWh when using the global warming potential over a time horizon of 100 years (GWP100. Nonetheless, this is still below that of fossil energy sources without the use of carbon capture and sequestration technologies. We identified the dams most promising for capturing methane for use as alternative energy source. The spread among the ~1500 hydropower plants analysed in this study is large and highlights the importance of case-by-case examinations.

  4. The chemistry of dimethyl carbonate.

    Science.gov (United States)

    Tundo, Pietro; Selva, Maurizio

    2002-09-01

    Dimethyl carbonate (DMC) is a versatile compound that represents an attractive eco-friendly alternative to both methyl halides (or dimethyl sulfate) and phosgene for methylation and carbonylation processes, respectively. In fact, the reactivity of DMC is tunable: at T = 90 degrees C, methoxycarbonylations take place, whereas at higher reaction temperatures, methylation reactions are observed with a variety of nucleophiles. In the particular case of substrates susceptible to multiple alkylations (e.g., CH(2)-active compounds and primary amines), DMC allows unprecedented selectivity toward mono-C- and mono-N-methylation reactions. Nowadays produced by a clean process, DMC possesses properties of nontoxicity and biodegradability which makes it a true green reagent to use in syntheses that prevent pollution at the source. Moreover, DMC-mediated methylations are catalytic reactions that use safe solids (alkaline carbonates or zeolites), thereby avoiding the formation of undesirable inorganic salts as byproducts. The reactivity of other carbonates is reported as well: higher homologues of DMC (i.e., diethyl and dibenzyl carbonate), are excellent mono-C- and mono-N-alkylating agents, whereas asymmetrical methyl alkyl carbonates (ROCO(2)Me with R > or = C(3)) undergo methylation processes with a chemoselectivity up to 99%.

  5. Carbon and nitrogen losses through moulting in the Cape rock ...

    African Journals Online (AJOL)

    Exuviae contained a higher ash content, a 28,1 % lower organic carbon content indicating reabsorption, and a similar inorganic carbon content when compared with intermoult exoskeleton. Estimates for a lobster population occupying 100 m2 at Robben Island are that 228 g organic carbon and 57,3 g nitrogen are lost ...

  6. A simple stable carbon isotope method for investigating changes in the use of recent versus old carbon in oak.

    Science.gov (United States)

    McCarroll, Danny; Whitney, Matthew; Young, Giles H F; Loader, Neil J; Gagen, Mary H

    2017-08-01

    Stable carbon isotope ratios from early-wood (EW) and late-wood (LW) are used to test competing models of carbon storage and allocation, providing a cost-effective alternative to measuring and dating non-structural carbohydrates in mature temperate broad-leaf forest trees growing under natural conditions. Annual samples of EW and LW from seven mature oaks (Quercus robur L.) from Scotland, covering AD 1924-2012, were pooled, treated to isolate alpha-cellulose and pyrolysed to measure the carbon isotope ratios. Late-wood values are strongly correlated with summer temperature of the year of growth and EW contains the same signal offset by 1 year. After a warm summer, isotopic ratios of EW are similar to those of the preceding LW, but following cold summers they are relatively enriched. The results conflict with established models of isotopic variation within oak tree rings but support 'two-pool' models for storage of non-structural carbohydrates, with EW formation, which occurs prior to budburst, preferentially using young reserves accumulated in the previous summer. Under poor growing conditions trees access older reserves. Slight average isotopic enrichment of EW may be explained by preferential accumulation of reserves during warmer summers rather than by isotopic enrichment during starch formation in non-photosynthetic tissue. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Carbon nanotube fiber spun from wetted ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  8. Interactions between land use change and carbon cycle feedbacks: Land Use and Carbon Cycle Feedbacks

    Energy Technology Data Exchange (ETDEWEB)

    Mahowald, Natalie M. [Cornell Univ., Ithaca, NY (United States); Randerson, James T. [Univ. of California, Irvine, CA (United States); Lindsay, Keith [National Center for Atmospheric Research, Boulder, CO (United States); Munoz, Ernesto [National Center for Atmospheric Research, Boulder, CO (United States); Doney, Scott C. [Woods Hole Oceanographic Inst., Woods Hole, MA (United States); Lawrence, Peter [National Center for Atmospheric Research, Boulder, CO (United States); Schlunegger, Sarah [Cornell Univ., Ithaca, NY (United States); Princeton Univ., NJ (United States); Ward, Daniel S. [Cornell Univ., Ithaca, NY (United States); Princeton Univ., NJ (United States); Lawrence, David [National Center for Atmospheric Research, Boulder, CO (United States); Hoffman, Forrest M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-23

    We explore the role of human land use and land cover change (LULCC) in modifying the terrestrial carbon budget in simulations forced by Representative Concentration Pathway 8.5, extended to year 2300 by using the Community Earth System Model, . Overall, conversion of land (e.g., from forest to croplands via deforestation) results in a model-estimated, cumulative carbon loss of 490 Pg C between 1850 and 2300, larger than the 230 Pg C loss of carbon caused by climate change over this same interval. The LULCC carbon loss is a combination of a direct loss at the time of conversion and an indirect loss from the reduction of potential terrestrial carbon sinks. Approximately 40% of the carbon loss associated with LULCC in the simulations arises from direct human modification of the land surface; the remaining 60% is an indirect consequence of the loss of potential natural carbon sinks. Because of the multicentury carbon cycle legacy of current land use decisions, a globally averaged amplification factor of 2.6 must be applied to 2015 land use carbon losses to adjust for indirect effects. This estimate is 30% higher when considering the carbon cycle evolution after 2100. Most of the terrestrial uptake of anthropogenic carbon in the model occurs from the influence of rising atmospheric CO2 on photosynthesis in trees, and thus, model-projected carbon feedbacks are especially sensitive to deforestation.

  9. Modeling changes in organic carbon stocks for distinct soils in southeastern brazil after four eucalyptus rotations using the century model

    Directory of Open Access Journals (Sweden)

    Augusto Miguel Nascimento Lima

    2011-06-01

    Full Text Available Soil organic matter (SOM plays an important role in carbon (C cycle and soil quality. Considering the complexity of factors that control SOM cycling and the long time it usually takes to observe changes in SOM stocks, modeling constitutes a very important tool to understand SOM cycling in forest soils. The following hypotheses were tested: (i soil organic carbon (SOC stocks would be higher after several rotations of eucalyptus than in low-productivity pastures; (ii SOC values simulated by the Century model would describe the data better than the mean of observations. So, the aims of the current study were: (i to evaluate the SOM dynamics using the Century model to simulate the changes of C stocks for two eucalyptus chronosequences in the Rio Doce Valley, Minas Gerais State, Brazil; and (ii to compare the C stocks simulated by Century with the C stocks measured in soils of different Orders and regions of the Rio Doce Valley growing eucalyptus. In Belo Oriente (BO, short-rotation eucalyptus plantations had been cultivated for 4.0; 13.0, 22.0, 32.0 and 34.0 years, at a lower elevation and in a warmer climate, while in Virginópolis (VG, these time periods were 8.0, 19.0 and 33.0 years, at a higher elevation and in a milder climate. Soil samples were collected from the 0-20 cm layer to estimate C stocks. Results indicate that the C stocks simulated by the Century model decreased after 37 years of poorly managed pastures in areas previously covered by native forest in the regions of BO and VG. The substitution of poorly managed pastures by eucalyptus in the early 1970´s led to an average increase of C of 0.28 and 0.42 t ha-1 year-1 in BO and VG, respectively. The measured C stocks under eucalyptus in distinct soil Orders and independent regions with variable edapho-climate conditions were not far from the values estimated by the Century model (root mean square error - RMSE = 20.9; model efficiency - EF = 0.29 despite the opposite result obtained

  10. Wages and Higher Education Participation

    OpenAIRE

    Eleftheriou, Konstantinos; Athanasiou, George; Petrakis, Panagiotis

    2009-01-01

    The paper develops a model for the screening mechanism for higher education, within an adverse selection framework. Specifically it examines the effect of wage earned by high school graduates on higher education participation. The model pinpoints a positive relation between the “high school” wage and the number of candidates entered in higher education with positive influences on the quality of selection mechanism. An empirical examination is conducted, using U.S. data, in order to investigat...

  11. Organic chemistry of Murchison meteorite: Carbon isotopic fractionation

    Science.gov (United States)

    Yuen, G. U.; Blair, N. E.; Desmarais, D. J.; Cronin, J. R.; Chang, S.

    1986-01-01

    The carbon isotopic composition of individual organic compounds of meteoritic origin remains unknown, as most reported carbon isotopic ratios are for bulk carbon or solvent extractable fractions. The researchers managed to determine the carbon isotopic ratios for individual hydrocarbons and monocarboxylic acids isolated from a Murchison sample by a freeze-thaw-ultrasonication technique. The abundances of monocarboxylic acids and saturated hydrocarbons decreased with increasing carbon number and the acids are more abundant than the hydrocarbon with the same carbon number. For both classes of compounds, the C-13 to C-12 ratios decreased with increasing carbon number in a roughly parallel manner, and each carboxylic acid exhibits a higher isotopic number than the hydrocarbon containing the same number of carbon atoms. These trends are consistent with a kinetically controlled synthesis of higher homologues for lower ones.

  12. Biosynthesis of glycerol carbonate from glycerol by lipase in dimethyl carbonate as the solvent.

    Science.gov (United States)

    Lee, Kyung Hwa; Park, Chang-Ho; Lee, Eun Yeol

    2010-11-01

    Glycerol carbonate was synthesized from renewable glycerol and dimethyl carbonate using lipase in solvent-free reaction system in which excess dimethyl carbonate played as the reaction medium. A variety of lipases have been tested for their abilities to catalyze transesterification reaction, and Candida antartica lipase B and Novozyme 435 exhibited higher catalytic activities. The silica-coated glycerol with a 1:1 ratio was supplied to prevent two-phase formation between hydrophobic dimethyl carbonate and hydrophilic glycerol. Glycerol carbonate was successfully synthesized with more than 90% conversion from dimethyl carbonate and glycerol with a molar ratio of 10 using Novozyme 435-catalyzed transesterification at 70 °C. The Novozyme 435 [5% (w/w) and 20% (w/w)] and silica gel were more than four times recycled with good stability in a repeated batch operation for the solvent-free synthesis of glycerol carbonate.

  13. Effect of carbon content on the mechanical properties of medium carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Calik, Adnan [Dept. of Mechanical Education, Suleyman Demirel Univ., Isparta (Turkey); Duzgun, Akin [Civil Engineering Dept., Ataturk Univ., Erzurum (Turkey); Sahin, Osman [Physics Dept., M. Kemal Univ., Hatay (Turkey); Ucar, Nazim [Physics Dept., Suleyman Demirel Univ., Isparta (Turkey)

    2010-05-15

    The mechanical properties of medium-carbon steels with a carbon content ranging from 0.30 to 0.55 wt.% were investigated by tensile and microhardness tests at room temperature. It was observed that the higher carbon content results in an increase in yield stress and ultimate tensile stress, while the elongation remains essentially constant. The results were explained by the hindering of dislocation motion associated with solid solution hardening. (orig.)

  14. 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 ...

  15. Net Ecosystem Carbon Flux

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Net Ecosystem Carbon Flux is defined as the year-over-year change in Total Ecosystem Carbon Stock, or the net rate of carbon exchange between an ecosystem and the...

  16. 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 "Invisible ...

  17. Using a Regional Cluster of AmeriFlux Sites in Central California to Advance Our Knowledge on Decadal-Scale Ecosystem-Atmosphere Carbon Dioxide Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Baldocchi, Dennis [Univ. of California, Berkeley, CA (United States)

    2015-03-24

    Continuous eddy convariance measurements of carbon dioxide, water vapor and heat were measured continuously between an oak savanna and an annual grassland in California over a 4 year period. These systems serve as representative sites for biomes in Mediterranean climates and experience much seasonal and inter-annual variability in temperature and precipitation. These sites hence serve as natural laboratories for how whole ecosystem will respond to warmer and drier conditions. The savanna proved to be a moderate sink of carbon, taking up about 150 gC m-2y-1 compared to the annual grassland, which tended to be carbon neutral and often a source during drier years. But this carbon sink by the savanna came at a cost. This ecosystem used about 100 mm more water per year than the grassland. And because the savanna was darker and rougher its air temperature was about 0.5 C warmer. In addition to our flux measurements, we collected vast amounts of ancillary data to interpret the site and fluxes, making this site a key site for model validation and parameterization. Datasets consist of terrestrial and airborne lidar for determining canopy structure, ground penetrating radar data on root distribution, phenology cameras monitoring leaf area index and its seasonality, predawn water potential, soil moisture, stem diameter and physiological capacity of photosynthesis.

  18. Humic substances-part 7: the biogeochemistry of dissolved organic carbon and its interactions with climate change.

    Science.gov (United States)

    Porcal, Petr; Koprivnjak, Jean-François; Molot, Lewis A; Dillon, Peter J

    2009-09-01

    production and loss of DOC as CO(2) from boreal lakes may also be affected by changing climate. Climate change is unlikely to be uniform spatially with some regions becoming wetter while others become drier. As a result, rates of change in DOC export and concentrations will vary regionally and the changes may be non-linear. Climate change models predict that higher temperatures are likely to occur over most of the boreal forests in North America, Europe, and Asia over the next century. Climate change is also expected to affect the severity and frequency of storm and drought events. Two general climate scenarios emerge with which to examine possible DOC trends: warmer and wetter or warmer and drier. Increasing temperature and hydrological changes (specifically, runoff) are likely to lead to changes in the quality and quantity of DOC export from terrestrial sources to rivers and lakes as well as changes in DOC processing rates in lakes. This will alter the quality and concentrations of DOC and its constituents as well as its interactions with trace metals and the availability of nutrients. In addition, export rates of nutrients and metals will also change in response to changing runoff. Processing of DOC within lakes may impact climate depending on the extent to which DOC is mineralized to dissolved inorganic carbon (DIC) and evaded to the atmosphere or settles as particulate organic carbon (POC) to bottom sediments and thereby remaining in the lake. The partitioning of DOC between sediments and the atmosphere is a function of pH. Decreased DOC concentrations may also limit the burial of sulfate, as FeS, in lake sediments, thereby contributing acidity to the water by increasing the formation of H(2)S. Under a warmer and drier scenario, if lake water levels fall, previously stored organic sediments may be exposed to greater aeration which would lead to greater CO(2) evasion to the atmosphere. The interaction of trace metals with DOC may be significantly altered by climate

  19. Effective Communication in Higher Education

    Science.gov (United States)

    Howard, Melissa

    2014-01-01

    The intent for this paper is to show that communication within the higher education field is a current problem. By looking first at the different styles, forms, and audiences for communication, the reader will hopefully gain perspective as to why this is such a problem in higher education today. Since the Millennial generation is the newest set of…

  20. Disruptive Technologies in Higher Education

    Science.gov (United States)

    Flavin, Michael

    2012-01-01

    This paper analyses the role of "disruptive" innovative technologies in higher education. In this country and elsewhere, Higher Education Institutions (HEIs) have invested significant sums in learning technologies, with Virtual Learning Environments (VLEs) being more or less universal, but these technologies have not been universally…

  1. Makerere Journal of Higher Education

    African Journals Online (AJOL)

    Makerere Journal of Higher Education (MAJOHE) is the official publication of the East African School of Higher Education Studies and Development (Makerere University). The goal of the Journal is to provide a visible outlet for definitive articles that discuss the theory, practice and policies relating to the role, development, ...

  2. Extremal Higher Spin Black Holes

    NARCIS (Netherlands)

    Bañados, M.; Castro, A.; Faraggi, A.; Jottar, J.I.

    The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal

  3. Queering Transformation in Higher Education

    Science.gov (United States)

    Msibi, Thabo

    2013-01-01

    Transformation in higher education has tended to focus on race and sex, at the expense of other forms of discrimination. This article addresses the silencing of "queer" issues in higher education. Using queer theory as a framework, and drawing on current literature, popular media reports, two personal critical incidents and a project…

  4. Higher Education and Ethical Value

    Science.gov (United States)

    Lee, Jeong-Kyu

    2017-01-01

    The purpose of this study is to explore the importance of ethical value in higher education as well as the relevance between ethical value and higher education. In order to examine the study logically, three research questions are addressed: First, what is value, ethical value, and Asiatic ethical value? Second, for whom and what is higher…

  5. The Higher Education Research Archipelago

    Science.gov (United States)

    Macfarlane, Bruce

    2012-01-01

    Ever since he stumbled into doing higher education research as a young academic in the 1980s, the author has been trying to understand it as a "field" of study. His career, as a former business lecturer, then an academic developer and now an associate professor for higher education working in an Education Faculty has given him opportunities to see…

  6. The Overselling of Higher Education

    Science.gov (United States)

    Leef, George C.

    2006-01-01

    There is not enough substance behind a degree to warrant the ubiquitous belief that a stint in higher education is a "sine qua non" for success in America. While college diplomas may translate into higher-paying jobs for some, high school signifies little in the way of education these days, so jaded employers' estimates of the real value of…

  7. Innovation Processes in Higher Education.

    Science.gov (United States)

    Berg, Barbro; Ostergren, Bertil

    1979-01-01

    Innovation processes in the Swedish Higher Education System are described and related to a general theory of innovation. Using the theories of Kurt Lewin, characteristics of higher education as a social system and factors which determine the nature of the forces towards a certain type of change are defined. (JMF)

  8. Latino Males in Higher Education

    Science.gov (United States)

    Excelencia in Education, 2016

    2016-01-01

    This 2016 fact sheet profiles the status of Latino males in higher education, providing information on population, college enrollment, and educational attainment. While college enrollment among Latino males continues to increase, they still lag behind Latino females in college enrollment--a disparity that increases as the level of higher education…

  9. Polish Higher Education: Intersectoral Distinctiveness

    Science.gov (United States)

    Musial, Joanna

    2014-01-01

    This study analyzes degrees of differences between the private and public sectors of Polish higher education. It finds them to be strong: Polish private institutions function very differently from Polish public institutions and these differences correspond with those found in the literature on higher education elsewhere in the world. Polish…

  10. Higher education and economic growth

    OpenAIRE

    Richard H. Mattoon

    2006-01-01

    The future of higher education and its relationship to economic growth were the focus of a one-day conference at the Chicago Fed on November 2, 2005. Cosponsored by the bank, the Committee on Institutional Cooperation, and the Midwestern Higher Education Compact, the event brought together over 100 academic, business, and government leaders.

  11. Innovations in Higher Education? Hah!

    Science.gov (United States)

    Kirschner, Ann

    2012-01-01

    One can hardly mention higher education today without hearing the word "innovation," or its understudies "change," "reinvention," "transformation." Last summer the National Governors Association opened its meeting with a plenary session on higher education, innovation, and economic growth. But there is nothing funny about the need for innovation…

  12. Higher Education, Poverty and Development

    Science.gov (United States)

    Tilak, Jandhyala B. G.

    2010-01-01

    There is a presumption among many policy makers that higher education is not necessary for economic growth and development; it is literacy and basic education and at best secondary education that are argued to be important. Estimates of internal rate of return contributed to strengthening of such a presumption. Accordingly, higher education has…

  13. Higher Education: Open for Business

    Science.gov (United States)

    Gilde, Christian, Ed.

    2007-01-01

    This book addresses a problem in higher learning, which is newly recognized in the academic spotlight: the overcommercialization of higher education. The book asks that you, the reader, think about the following: Did you go to a Coke or Pepsi school? Do your children attend a Nike or Adidas school? Is the college in your town a Dell or Gateway…

  14. Strategic Planning for Higher Education.

    Science.gov (United States)

    Kotler, Philip; Murphy, Patrick E.

    1981-01-01

    The framework necessary for achieving a strategic planning posture in higher education is outlined. The most important benefit of strategic planning for higher education decision makers is that it forces them to undertake a more market-oriented and systematic approach to long- range planning. (Author/MLW)

  15. Yeast-based microporous carbon materials for carbon dioxide capture.

    Science.gov (United States)

    Shen, Wenzhong; He, Yue; Zhang, Shouchun; Li, Junfen; Fan, Weibin

    2012-07-01

    A hierarchical microporous carbon material with a Brunauer-Emmett-Teller surface area of 1348 m(2) g(-1) and a pore volume of 0.67 cm(3) g(-1) was prepared from yeast through chemical activation with potassium hydroxide. This type of material contains large numbers of nitrogen-containing groups (nitrogen content >5.3 wt%), and, consequently, basic sites. As a result, this material shows a faster adsorption rate and a higher adsorption capacity of CO(2) than the material obtained by directly carbonizing yeast under the same conditions. The difference is more pronounced in the presence of N(2) or H(2)O, showing that chemical activation of discarded yeast with potassium hydroxide could afford high-performance microporous carbon materials for the capture of CO(2). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Higher Franz-Reidemeister torsion

    CERN Document Server

    Igusa, Kiyoshi

    2002-01-01

    The book is devoted to the theory of topological higher Franz-Reidemeister torsion in K-theory. The author defines the higher Franz-Reidemeister torsion based on Volodin's K-theory and Borel's regulator map. He describes its properties and generalizations and studies the relation between the higher Franz-Reidemeister torsion and other torsions used in K-theory: Whitehead torsion and Ray-Singer torsion. He also presents methods of computing higher Franz-Reidemeister torsion, illustrates them with numerous examples, and describes various applications of higher Franz-Reidemeister torsion, particularly for the study of homology of mapping class groups. Packed with up-to-date information, the book provides a unique research and reference tool for specialists working in algebraic topology and K-theory.

  17. The effect of permafrost thaw on short- and long-term carbon accumulation in permafrost mires

    Science.gov (United States)

    Olid, Carolina; Klaminder, Jonatan; Monteux, Sylvain; Johansson, Margareta; Dorrepaal, Ellen

    2017-04-01

    Permafrost stores twice as much carbon (C) as is currently present in the atmosphere. During recent years, warmer temperatures in the Arctic has caused rapid thawing of permafrost, which have dramatically altered permafrost C storage by increasing both microbial decomposition and plant productivity. Although current research focuses on the effects of climate change on these two processes, there are still no scientific consensus about the magnitude or even the direction of future C feedbacks from permafrost ecosystems. Field manipulation experiments have been widely used during the last decade to improve our knowledge about the net effects of permafrost thaw in the permafrost C storage. However, due to the slow response (decades) of permafrost ecosystems to environmental changes and the short-time nature of these experiments (usually shorter than 5-9 years), there are still concerns when attempting to extrapolate the results to predict long term effects. In addition, measurements are mostly taken exclusively during the summer season, without taking into account inter-annual variability in C fluxes and underestimating microbial activity throughout the cold season. The need to develop a comprehensive understanding of C fluxes over the entire year and at long temporal scales sets the basis of this study. This study aims to quantify the effects of permafrost thawing in permafrost C fluxes using a 12 years permafrost thaw experiment in northern Sweden. Our aims were to quantify the effect of permafrost thaw in both decomposition and primary production in active layer and newly thawed permafrost, and its implications for the C balance. Based on previous observations, we hypothesized that 1) soil decomposition rates were higher in manipulated thaw plots. However, 2) the observed increase in nutrients availability and the higher presence of vascular plants after thawing stimulate primary production, which compensates to some extent the increased C losses by respiration. To

  18. Carbon-carbon grid for ion engines

    Science.gov (United States)

    Garner, Charles E. (Inventor)

    1995-01-01

    A method and apparatus of manufacturing a grid member for use in an ion discharge apparatus provides a woven carbon fiber in a matrix of carbon. The carbon fibers are orientated to provide a negatibe coefficient of thermal expansion for at least a portion of the grid member's operative range of use.

  19. Carbon dioxide sequestration by mineral carbonation

    NARCIS (Netherlands)

    Huijgen, W.J.J.

    2007-01-01

    The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept

  20. Scale-up of Carbon/Carbon Bipolar Plates

    Energy Technology Data Exchange (ETDEWEB)

    David P. Haack

    2009-04-08

    This project was focused upon developing a unique material technology for use in PEM fuel cell bipolar plates. The carbon/carbon composite material developed in this program is uniquely suited for use in fuel cell systems, as it is lightweight, highly conductive and corrosion resistant. The project further focused upon developing the manufacturing methodology to cost-effectively produce this material for use in commercial fuel cell systems. United Technology Fuel Cells Corp., a leading fuel cell developer was a subcontractor to the project was interested in the performance and low-cost potential of the material. The accomplishments of the program included the development and testing of a low-cost, fully molded, net-shape carbon-carbon bipolar plate. The process to cost-effectively manufacture these carbon-carbon bipolar plates was focused on extensively in this program. Key areas for cost-reduction that received attention in this program was net-shape molding of the detailed flow structures according to end-user design. Correlations between feature detail and process parameters were formed so that mold tooling could be accurately designed to meet a variety of flow field dimensions. A cost model was developed that predicted the cost of manufacture for the product in near-term volumes and long-term volumes (10+ million units per year). Because the roduct uses lowcost raw materials in quantities that are less than competitive tech, it was found that the cost of the product in high volume can be less than with other plate echnologies, and can meet the DOE goal of $4/kW for transportation applications. The excellent performance of the all-carbon plate in net shape was verified in fuel cell testing. Performance equivalent to much higher cost, fully machined graphite plates was found.

  1. Composite carbon foam electrode

    Science.gov (United States)

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1997-05-06

    Carbon aerogels used as a binder for granulated materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

  2. Teaching Creatively in Higher Education

    DEFF Research Database (Denmark)

    Chemi, Tatiana; Zhou, Chunfang

    The topic of this booklet is a synthesis of relevant research in the field of creativity in higher education, with focus on creative teaching methods. By means of literature review and research findings this booklet describes a wide range of contexts and effects on student learning and develop......­ment, together with teacher motivation and overall satisfaction. This booklet meets the need for renewal and creation in higher education, in order to address the challenges of the future, focusing on the benefits of teaching crea­tively at higher education....

  3. [Characteristics of carbon storage of Inner Mongolia forests: a review].

    Science.gov (United States)

    Yang, Hao; Hu, Zhong-Min; Zhang, Lei-Ming; Li, Sheng-Gong

    2014-11-01

    Forests in Inner Mongolia account for an important part of the forests in China in terms of their large area and high living standing volume. This study reported carbon storage, carbon density, carbon sequestration rate and carbon sequestration potential of forest ecosystems in Inner Mongolia using the biomass carbon data from the related literature. Through analyzing the data of forest inventory and the generalized allometric equations between volume and biomass, previous studies had reported that biomass carbon storage of the forests in Inner Mongolia was about 920 Tg C, which was 12 percent of the national forest carbon storage, the annual average growth rate was about 1.4%, and the average of carbon density was about 43 t · hm(-2). Carbon storage and carbon density showed an increasing trend over time. Coniferous and broad-leaved mixed forest, Pinus sylvestris var. mongolica forest and Betula platyphylla forest had higher carbon sequestration capacities. Carbon storage was reduced due to human activities such as thinning and clear cutting. There were few studies on carbon storage of the forests in Inner Mongolia with focus on the soil, showing that the soil car- bon density increased with the stand age. Study on the carbon sequestration potential of forest ecosystems was still less. Further study was required to examine dynamics of carbon storage in forest ecosystems in Inner Mongolia, i. e., to assess carbon storage in the forest soils together with biomass carbon storage, to compute biomass carbon content of species organs as 45% in the allometric equations, to build more species-specific and site-specific allometric equations including root biomass for different dominant species, and to take into account the effects of climate change on carbon sequestration rate and carbon sequestration potential.

  4. Some thoughts on global climate change: will it get warmer and warmer?

    Directory of Open Access Journals (Sweden)

    WenJun Zhang

    2012-03-01

    Full Text Available Many studies discussed climate change without considering the complexity of climate system. In our view, climate system is a complex and non-linear system. It possesses all properties that a complex system will have, such as non-linearity, chaos, catastrophe, multiple stable or unstable equilibrium states, etc. It is increasingly obvious that the equilibrium state of climate system is being broken by destructive human activities. There are several possibilities that global climate will proceed. We would not exactly predict what outcome will finally occur if destructive human activities continue. In the farther future, in addition to the scenario of continuous warming, there is also possibility that the climate would proceed and reach a new stable or unstable equilibrium state, and the new equilibrium state would be realized in a smooth and continuous way, or realized in an abrupt way by jumping or plummeting. Recent years' and the coming tens of years' unusual change in global climate would be a prelude for dramatic climate change in the far future. We found that global annualmean temperature since 1880 has been rising in sinusoidal-type, similar to a superposition of sine curve and exponential curve, in which a periodicity of about 60 years existed and in the first ~40 years the temperature rose and in the second ~20 years it declined or approximately to be constant. Accordingly, we predicted that the global annual mean temperature had reached a peak around 2005, and would decline or be approximately constant until around 2030. Some models, equations and parameters on climate change were also developed based on past hundreds of years' historical records.

  5. Carbon Nanomembranes

    Science.gov (United States)

    Angelova, Polina; Gölzhäuser, Armin

    2017-03-01

    This chapter describes the formation and properties of one nanometer thick carbon nanomembranes (CNMs), made by electron induced cross-linking of aromatic self-assembled monolayers (SAMs). The cross-linked SAMs are robust enough to be released from the surface and placed on solid support or over holes as free-standing membranes. Annealing at 1000K transforms CNMs into graphene accompanied by a change of mechanical stiffness and electrical resistance. The developed fabrication approach is scalable and provides molecular level control over thickness and homogeneity of the produced CNMs. The mechanisms of electron-induced cross-linking process are discussed in details. A variety of polyaromatic thiols: oligophenyls as well as small and extended condensed polycyclic hydrocarbons have been successfully employed, demonstrating that the structural and functional properties of the resulting nanomembranes are strongly determined by the structure of molecular monolayers. The mechanical properties of CNMs (Young's modulus, tensile strength and prestress) are characterized by bulge testing. The interpretation of the bulge test data relates the Young's modulus to the properties of single molecules and to the structure of the pristine SAMs. The gas transport through the CNM is measured onto polydimethylsiloxane (PDMS) - thin film composite membrane. The established relationship of permeance and molecular size determines the molecular sieving mechanism of permeation through this ultrathin sheet.

  6. Using organoclays to enhance carbon filtration.

    Science.gov (United States)

    Alther, George

    2002-01-01

    Organoclays have found increased acceptance as pre-treatment for activated carbon adsorption systems in both groundwater and wastewater cleanup. The reason is that activated carbon tends to become quickly blinded by large organic molecules of low solubility, particularly oils. However, it is also well established that activated carbon is more efficient at low concentrations of organic contaminants than at higher ones, i.e. at less than 1 ppm. With organoclays it is exactly the opposite, they are better at removing organics at higher concentrations, above 3 ppm. Therefore it is cost effective in these applications to use two or more vessels in series, the first one filled with organoclay, the remainder with activated carbon. The economics make sense, even though the organoclay is not regenerated, because of the reduction in down time every time a carbon vessel has to be changed out. Use of organoclays increases the volume treated by carbon in many applications seven to nine fold. In the case of other organic contaminants, as the aqueous solubility increases, the efficiency decreases, except in the case of methylene chloride, which it removes at far higher efficiency then carbon. This article presents the results of a series of tests, including Kd determinations, jar tests, and mini-column tests. These tests determined the adsorption capacity and efficiency of organoclay and activated carbon for the removal of benzene, toluene, xylene and naphtalene from water. These tests were followed by adding the four compounds into one container to see if the combination of organoclay, followed by carbon, would be more efficient then each sorbent alone. The tests also compared the efficiency of organoclay versus carbon for the removal of various oils from water.

  7. Scientific collaboratories in higher education

    DEFF Research Database (Denmark)

    Sonnenwald, Diane H.; Li, Bin

    2003-01-01

    Scientific collaboratories hold the promise of providing students access to specialized scientific instruments, data and experts, enabling learning opportunities perhaps otherwise not available. However, evaluation of scientific collaboratories in higher education has lagged behind...

  8. The Legalization of Higher Education

    Science.gov (United States)

    Badke, Lara K.

    2017-01-01

    A complete discussion of intellectual property (IP), faculty rights, and the public good requires a thorough framing of higher education's legal context, from which the rise of legalistic criteria (or legalization) and current IP regime have grown.

  9. Categorification and higher representation theory

    CERN Document Server

    Beliakova, Anna

    2017-01-01

    The emergent mathematical philosophy of categorification is reshaping our view of modern mathematics by uncovering a hidden layer of structure in mathematics, revealing richer and more robust structures capable of describing more complex phenomena. Categorified representation theory, or higher representation theory, aims to understand a new level of structure present in representation theory. Rather than studying actions of algebras on vector spaces where algebra elements act by linear endomorphisms of the vector space, higher representation theory describes the structure present when algebras act on categories, with algebra elements acting by functors. The new level of structure in higher representation theory arises by studying the natural transformations between functors. This enhanced perspective brings into play a powerful new set of tools that deepens our understanding of traditional representation theory. This volume exhibits some of the current trends in higher representation theory and the diverse te...

  10. Teaching Creatively in Higher Education

    DEFF Research Database (Denmark)

    Chemi, Tatiana; Zhou, Chunfang

    The topic of this booklet is a synthesis of relevant research in the field of creativity in higher education, with focus on creative teaching methods. By means of literature review and research findings this booklet describes a wide range of contexts and effects on student learning and develop­me......­ment, together with teacher motivation and overall satisfaction. This booklet meets the need for renewal and creation in higher education, in order to address the challenges of the future, focusing on the benefits of teaching crea­tively at higher education.......The topic of this booklet is a synthesis of relevant research in the field of creativity in higher education, with focus on creative teaching methods. By means of literature review and research findings this booklet describes a wide range of contexts and effects on student learning and develop...

  11. Progressive problems higher grade physics

    CERN Document Server

    Kennedy, William

    2001-01-01

    This book fully covers all three Units studied in Scotland's Higher Grade Physics course, providing a systematic array of problems (from the simplest to the most difficult) to lead variously abled pupils to examination success.

  12. Solving higher curvature gravity theories

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Sumanta [IUCAA, Pune (India); SenGupta, Soumitra [Indian Association for the Cultivation of Science, Theoretical Physics Department, Kolkata (India)

    2016-10-15

    Solving field equations in the context of higher curvature gravity theories is a formidable task. However, in many situations, e.g., in the context of f(R) theories, the higher curvature gravity action can be written as an Einstein-Hilbert action plus a scalar field action. We show that not only the action but the field equations derived from the action are also equivalent, provided the spacetime is regular. We also demonstrate that such an equivalence continues to hold even when the gravitational field equations are projected on a lower-dimensional hypersurface. We have further addressed explicit examples in which the solutions for Einstein-Hilbert and a scalar field system lead to solutions of the equivalent higher curvature theory. The same, but on the lower-dimensional hypersurface, has been illustrated in the reverse order as well. We conclude with a brief discussion on this technique of solving higher curvature field equations. (orig.)

  13. Disruptive technologies in higher education

    OpenAIRE

    Flavin, Michael

    2012-01-01

    This paper analyses the role of ‘‘disruptive’’ innovative technologies in higher education. In this country and elsewhere, Higher Education Institutions (HEIs) have invested significant sums in learning technologies, with Virtual Learning Environments (VLEs) being more or less universal, but these technologies have not been universally adopted and used by students and staff. Instead, other technologies not owned or controlled by HEIs are widely used to support learning and teaching. According...

  14. Black Holes in Higher Dimensions

    Directory of Open Access Journals (Sweden)

    Reall Harvey S.

    2008-09-01

    Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

  15. Anomalous electron transport in metal/carbon multijunction devices by engineering of the carbon thickness and selecting metal layer

    Science.gov (United States)

    Dwivedi, Neeraj; Dhand, Chetna; Rawal, Ishpal; Kumar, Sushil; Malik, Hitendra K.; Lakshminarayanan, Rajamani

    2017-06-01

    A longstanding concern in the research of amorphous carbon films is their poor electrical conductivity at room temperature which constitutes a major barrier for the development of cost effective electronic and optoelectronic devices. Here, we propose metal/carbon hybrid multijunction devices as a promising facile way to overcome room temperature electron transport issues in amorphous carbon films. By the tuning of carbon thickness and swapping metal layers, we observe giant (upto ˜7 orders) reduction of electrical resistance in metal/carbon multijunction devices with respect to monolithic amorphous carbon device. We engineer the maximum current (electrical resistance) from about 10-7 to 10-3 A (˜107 to 103 Ω) in metal (Cu or Ti)/carbon hybrid multijunction devices with a total number of 10 junctions. The introduction of thin metal layers breaks the continuity of relatively higher resistance carbon layer as well as promotes the nanostructuring of carbon. These contribute to low electrical resistance of metal/carbon hybrid multijunction devices, with respect to monolithic carbon device, which is further reduced by decreasing the thickness of carbon layers. We also propose and discuss equivalent circuit model to explain electrical resistance in monolithic carbon and metal/carbon multijunction devices. Cu/carbon multijunction devices display relatively better electrical transport than Ti/carbon devices owing to low affinity of Cu with carbon that restricts carbide formation. We also observe that in metal/carbon multijunction devices, the transport mechanism changes from Poole-Frenkel/Schottky model to the hopping model with a decrease in carbon thickness. Our approach opens a new route to develop carbon-based inexpensive electronic and optoelectronic devices.

  16. The changing Arctic carbon cycle: using the past to understand terrestrial-aquatic linkages

    Science.gov (United States)

    Anderson, N. J.; van Hardenbroek, M.; Jones, V.; McGowan, S.; Langdon, P. G.; Whiteford, E.; Turner, S.; Edwards, M. E.

    2016-12-01

    Predicted shifts in terrestrial vegetation cover associated with Arctic warming are altering the delivery and processing of carbon to aquatic ecosystems. This process could determine whether lakes are net carbon sources or sinks and, because lake density is high in many Arctic areas, may alter regional carbon budgets. Lake sediment records integrate information from within the lake and its catchment and can be used quantify past vegetation shifts associated with known climatic episodes of warmer (Holocene Thermal Maximum) and cooler (Neoglacial) conditions. We analysed sediment cores located in different Arctic vegetation biomes (tundra, shrub, forested) in Greenland, Norway and Alaska and used biochemical (algal pigments, stable isotopes) remains to evaluate whether past vegetation shifts were associated with changes in ecosystem carbon processing and biodiversity. When lake catchments were sparsely vegetated and soil vegetation was limited ultra-violet radiation (UVR) screening pigments indicate clear lake waters, scarce dissolved organic carbon/ matter (DOC/M). Moderate vegetation development (birch scrub in Norway; herb tundra in Greenland) appears to enhance delivery of DOM to lakes, and to stimulate algal production which is apparently linked to heterotrophic carbon processing pathways (e.g. algal mixotrophy, nutrient release via the microbial loop). Mature forest cover (in Alaska and Norway) supressed lake autotrophic production, most likely because coloured DOM delivered from catchment vegetation limited light availability. During wetter periods when mires developed lake carbon processing also changed, indicating that hydrological delivery of terrestrial DOM is also important. Therefore, future changes in Arctic vegetation and precipitation patterns are highly likely to alter the way that arctic ecosystems process carbon. Our approach provides an understanding of how ecosystem diversity and carbon processing respond to past climate change and the difficulty

  17. History of ultrahigh carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Wadsworth, J.; Sherby, O.D.

    1997-06-20

    The history and development of ultrahigh carbon steels (i.e., steels containing between 1 and 2.l percent C and now known as UHCS) are described. The early use of steel compositions containing carbon contents above the eutectoid level is found in ancient weapons from around the world. For example, both Damascus and Japanese sword steels are hypereutectoid steels. Their manufacture and processing is of interest in understanding the role of carbon content in the development of modern steels. Although sporadic examples of UHCS compositions are found in steels examined in the early part of this century, it was not until the mid-1970s that the modern study began. This study had its origin in the development of superplastic behavior in steels and the recognition that increasing the carbon content was of importance in developing that property. The compositions that were optimal for superplasticity involved the development of steels that contained higher carbon contents than conventional modern steels. It was discovered, however, that the room temperature properties of these compositions were of interest in their own right. Following this discovery, a period of intense work began on understanding their manufacture, processing, and properties for both superplastic forming and room temperature applications. The development of superplastic cast irons and iron carbides, as well as those of laminated composites containing UHCS, was an important part of this history.

  18. Mutagenicity of carbon nanomaterials.

    Science.gov (United States)

    Wallin, Håkan; Jacobsen, Nicklas Raun; White, Paul A; Gingerich, John; Møller, Peter; Loft, Steffen; Vogel, Ulla

    2011-02-01

    Carbon nanomaterials such carbon nanotubes, graphene and fullerenes are some the most promising nanomaterials. Although carbon nanomaterials have been reported to possess genotoxic potential, it is imperitive to analyse the data on the genotoxicity of carbon nanomaterials in vivo and in vitro and check the validity and predictability of different assays.

  19. Mutagenicity of carbon nanomaterials

    DEFF Research Database (Denmark)

    Wallin, Håkan; Jacobsen, Nicklas Raun; White, Paul A

    2011-01-01

    Carbon nanomaterials such carbon nanotubes, graphene and fullerenes are some the most promising nanomaterials. Although carbon nanomaterials have been reported to possess genotoxic potential, it is imperitive to analyse the data on the genotoxicity of carbon nanomaterials in vivo and in vitro...

  20. Permafrost-carbon complexities

    NARCIS (Netherlands)

    Vonk, J.E.; Gustafsson, Ö.

    2013-01-01

    The thawing and decomposition of carbon stored in permafrost generates greenhouse gases that could further intensify global warming. Currently, most of the thawed carbon is assumed to be converted to greenhouse gases, such as carbon dioxide and methane, and carbon decomposition is thought

  1. Carbon nanotube composite materials

    Science.gov (United States)

    O'Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  2. Carbon repression in Aspergilli.

    NARCIS (Netherlands)

    Ruijter, G.J.G.; Visser, J.

    1997-01-01

    Many microorganisms prefer easily metabolizable carbon sources over alternative, less readily metabolized carbon sources. One of the mechanisms to achieve this is repression of the synthesis of enzymes related to catabolism of the alternative carbon sources, i.e. carbon repression. It is now clear

  3. Pyrolyzed thin film carbon

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  4. Carbon-based spintronics

    Science.gov (United States)

    Chen, Peng; Zhang, GuangYu

    2013-01-01

    Carbon-based spintronics refers mainly to the spin injection and transport in carbon materials including carbon nanotubes, graphene, fullerene, and organic materials. In the last decade, extraordinary development has been achieved for carbon-based spintronics, and the spin transport has been studied in both local and nonlocal spin valve devices. A series of theoretical and experimental studies have been done to reveal the spin relaxation mechanisms and spin transport properties in carbon materials, mostly for graphene and carbon nanotubes. In this article, we provide a brief review on spin injection and transport in graphene, carbon nanotubes, fullerene and organic thin films.

  5. Secondary Metabolites from Higher Fungi.

    Science.gov (United States)

    Chen, He-Ping; Liu, Ji-Kai

    Secondary metabolites of higher fungi (mushrooms) are an underexplored resource compared to plant-derived secondary metabolites. An increasing interest in mushroom natural products has been noted in recent years. This chapter gives a comprehensive overview of the secondary metabolites from higher fungi, with 765 references highlighting the isolation, structure elucidation, biological activities, chemical syntheses, and biosynthesis of pigments, nitrogen-containing compounds, and terpenoids from mushrooms. Mushroom toxins are also included in each section.In a section on pigments of higher fungi, pigments are classified into four categories, namely, those from the shikimate-chorismate, acetate-malonate, and mevalonate biosynthetic pathways, and pigments containing nitrogen, with 145 references covering the years 2010-2016.In a section on other nitrogen-containing compounds of higher fungi, compounds are categorized primarily into nitrogen heterocycles, nucleosides, non-protein amino acids, cyclic peptides, and sphingolipids, with 65 references covering the years 2010-2016. In turn, in a section describing terpenoids of higher fungi, the sesquiterpenoids and diterpenoids are thoroughly elaborated, spanning the years 2001-2016, and 2009-2016, respectively. The divergent biosynthetic pathways from farnesyl pyrophosphate to sesquiterpenoids are also described. Selected triterpenoids with novel structures and promising biological activities, including lanostanes and ergostanes, are reported from the genus Ganoderma, and the fungi Antrodia cinnamomea and Poria cocos. In addition, cucurbitanes and saponaceolides are also compiled in this section.

  6. Wood - a carbon depot

    OpenAIRE

    Lipušček, Igor; Tišler, Vesna

    2003-01-01

    The article examines the global movement of carbon dioxide, the most important greenhouse gas due to its large quantities. We studied the carbon cycle with possibilities of its extension, and analysed the mechanisms that remove carbon dioxide from the atmosphere and bind it into solid substances for a longer period of time. The focus was on carbon dioxide sink into biomass and carbon deposit in wood. On the basis of wood component data and chemical analysis of the components, we calculated th...

  7. FACEBOOK COMMUNICATION IN HIGHER EDUCATION

    Directory of Open Access Journals (Sweden)

    Emanuela Maria AVRAM

    2014-11-01

    Full Text Available The social networks have been growing steadily in recent years. Facebook, one of the most popular social networks, is a modern means of communication and socialization that has taken lately more ground in higher education becoming an important academic tool in the communication process. Many universities have their own Facebook page, being used by both students and teachers, and creating Facebook groups increasingly facilitates communication with students. Thus, this paper aims to identify the importance that Facebook holds in the academic communication process and highlights the implications it has in higher education. The results reveal that this type of communication has gained more ground in academia creating real social communities, and students use it more and more for collaboration in various activities involved in the higher education system, but also for socializing and information.

  8. Higher-Order Program Generation

    DEFF Research Database (Denmark)

    Rhiger, Morten

    This dissertation addresses the challenges of embedding programming languages, specializing generic programs to specific parameters, and generating specialized instances of programs directly as executable code. Our main tools are higher-order programming techniques and automatic program generation...... infrastructure of higher-order functions, types, and modules. Furthermore, it has been observed that embedded programs can be restricted to those having simple types using a technique called ``phantom types''. We prove, using an idealized higher-order language, that such an embedding is sound (i.e., when all...... to the disproportion between general programs that can be executed in several contexts and their specialized counterparts that can be executed efficiently. However, stand-alone partial evaluation is usually too costly when a program must be specialized at run time. We introduce a collection of byte-code combinators...

  9. Electric-arc synthesis of soot with high content of higher fullerenes in parallel arc

    Science.gov (United States)

    Dutlov, A. E.; Nekrasov, V. M.; Sergeev, A. G.; Bubnov, V. P.; Kareev, I. E.

    2016-12-01

    Soot with a relatively high content of higher fullerenes (C76, C78, C80, C82, C84, C86, etc.) is synthesized in a parallel arc upon evaporation of pure carbon electrodes. The content of higher fullerenes in soot extract amounts to 13.8 wt % when two electrodes are simultaneously burnt in electric-arc reactor. Such a content is comparable with the content obtained upon evaporation of composite graphite electrodes with potassium carbonate impurity.

  10. Issues in Moroccan Higher Education

    Directory of Open Access Journals (Sweden)

    Mohammed Lazrak

    2017-06-01

    Full Text Available Historically, education has always been the springboard for socio-economic development of nations. Undoubtedly, education proved to be the catalyst of change and the front wagon that drives with it all the other wagons pertaining to other dynamic sectors. In effect, the role of education can be seen to provide pupils with the curriculum and hidden curriculum skills alike; teaching skills that will prepare them physically, mentally and socially for the world of work in later life. In Morocco, the country spends over 26% of its Gross Domestic Product (GDP on education. Unfortunately, though this number is important, Moroccan education (primary, secondary and higher education alike still suffers from the mismatch between the state expenditures on education and the general product in reality. In this article, an attempt is made to touch on some relevant issues pertaining to higher education with special reference to Morocco. First, it provides some tentative definitions, mission and functions of university and higher education. Second, it gives a historical sketch of the major reforms that took place in Morocco as well as the major changes pertaining to these reforms respectively. Third, it provides a general overview of the history of higher education in Morocco, it also tackles an issue related to governance in higher education which is cost sharing. Fourth, it delves into the history of English Language Teaching (ELT, lists some characteristics of the English Departments in Morocco. Fifth, it discusses the issue of private vs. public higher education. Last, but not least, it tackles the issue of Brain Drain.

  11. Danish aid to higher education

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    2016-01-01

    This piece comments on the role of higher education and universities in achieving the goals of Agenda 2030. It also asks if global academic collaboration is a new form of colonization or if researchers from the North can assist in decolonising the academy.......This piece comments on the role of higher education and universities in achieving the goals of Agenda 2030. It also asks if global academic collaboration is a new form of colonization or if researchers from the North can assist in decolonising the academy....

  12. Optimal Admission to Higher Education

    DEFF Research Database (Denmark)

    Albæk, Karsten

    This paper constructs higher education admission rules that maximise graduation rates and thus increase the skill level of the work force. An application shows that students with a low level in mathematics in secondary school ought to find it easier to be admitted to an economics programme than...... to law or psychology programmes, even though economics is the most difficult programme from which to graduate without a strong background in mathematics. Indirect gains from optimal admission include the potential of making whole cohorts of students more able to graduate with a higher education degree....

  13. Higher holonomies: comparing two constructions

    DEFF Research Database (Denmark)

    Schaetz, Florian; Arias Abad, Camilo

    2015-01-01

    We compare two different constructions of higher-dimensional parallel transport. On the one hand, there is the two-dimensional parallel transport associated with 2-connections on 2-bundles studied by Baez–Schreiber [2], Faria Martins–Picken [11] and Schreiber–Waldorf [12]. On the other hand......, there are the higher holonomies associated with flat superconnections as studied by Igusa [7], Block–Smith [3] and Arias Abad–Schätz [1]. We first explain how by truncating the latter construction one obtains examples of the former. Then we prove that the two-dimensional holonomies provided by the two approaches...

  14. Mergers in European Higher Education

    DEFF Research Database (Denmark)

    Rocha, Vera; Teixeira, Pedro N.; Biscaia, Ricardo

    2018-01-01

    In recent years, mergers have been widely used in higher education (HE) to achieve a variety of purposes, ranging from problems of institutional fragmentation to the lack of financial and academic viability, and low institutional efficiency and quality. However, despite a large stream of HE...... literature addressing those issues, there has been little attention to the link between funding-related problems and merger processes. Moreover, there is very little comparative research among different higher education systems experiencing those processes. In this paper, we map and characterize the recent...... merger processes....

  15. Systematic framework for carbon dioxide capture and utilization processes to reduce the global carbon dioxide emissions

    DEFF Research Database (Denmark)

    Frauzem, Rebecca; Plaza, Cristina Calvera; Gani, Rafiqul

    the two approaches that are currently being investigated, carbon capture and storage (CCS) and carbon capture and utilization (CCU) [1] to address this issue, the later approach is more promising as it reuses captured carbon dioxide, as a fuel, reactant, solvent, and others, to produce valuable products......In the year 2013, 9.5 billion metric tons of carbon dioxide gas was emitted into the air, and each year this amount is increasing [1]. Carbon dioxide emissions are of particular concern as they represent 80% of greenhouse gas emissions and therefore are a large contributor to global warming. Among....... There is not only a need for technologies for capture and utilization, via conversion, but also there are numerous questions that need to be resolved. For example, which higher value chemicals can be produced, what are their current demands and costs of production, and, how much of the captured carbon dioxide would...

  16. A Critical Review of Glucose Biosensors Based on Carbon Nanomaterials: Carbon Nanotubes and Graphene

    Directory of Open Access Journals (Sweden)

    William I. Milne

    2012-05-01

    Full Text Available There has been an explosion of research into the physical and chemical properties of carbon-based nanomaterials, since the discovery of carbon nanotubes (CNTs by Iijima in 1991. Carbon nanomaterials offer unique advantages in several areas, like high surface-volume ratio, high electrical conductivity, chemical stability and strong mechanical strength, and are thus frequently being incorporated into sensing elements. Carbon nanomaterial-based sensors generally have higher sensitivities and a lower detection limit than conventional ones. In this review, a brief history of glucose biosensors is firstly presented. The carbon nanotube and grapheme-based biosensors, are introduced in Sections 3 and 4, respectively, which cover synthesis methods, up-to-date sensing approaches and nonenzymatic hybrid sensors. Finally, we briefly outline the current status and future direction for carbon nanomaterials to be used in the sensing area.

  17. Preparation of porous carbon films from polyacrylonitrile by proton irradiation and carbonization

    Science.gov (United States)

    Lee, Hwa Su; Baek, Ga Young; Hwang, In-Tae; Jung, Chan-Hee; Choi, Jae-Hak

    2017-12-01

    Porous carbon films (PCFs) are widely used in various application fields, such as separation and water desalination as well as energy storage and conversion. In this study, PCFs were prepared from polyacrylonitrile (PAN) by proton irradiation and carbonization. Porous PAN films were prepared by a non-solvent-induced phase separation process. The porous PAN films were irradiated with proton ions, and then carbonized in a tube furnace at various fluences under an inert atmosphere. It was found that pore structures were well maintained during proton irradiation and high-temperature carbonization processes. The Raman and XRD results showed that pseudo-graphitic structures were formed by the carbonization of proton irradiated porous PAN films. The electrical conductivity of the prepared PCFs increased with an increasing carbonization temperature due to the formation of more graphitic structures at a higher temperature.

  18. The Chemistry of Extragalactic Carbon Stars

    Science.gov (United States)

    Woods, Paul; Walsh, C.; Cordiner, M. A.; Kemper, F.

    2013-01-01

    Prompted by the ongoing interest in Spitzer Infrared Spectrometer spectra of carbon stars in the Large Magellanic Cloud, we have investigated the circumstellar chemistry of carbon stars in low-metallicity environments. Consistent with observations, our models show that acetylene is particularly abundant in the inner regions of low metallicity carbon-rich asymptotic giant branch stars - more abundant than carbon monoxide. As a consequence, larger hydrocarbons have higher abundances at the metallicities of the Magellanic Clouds than in stars with solar metallicity. We also find that the oxygen and nitrogen chemistry is suppressed at lower metallicity, as expected. Finally, we calculate molecular line emission from carbon stars in the Large and Small Magellanic Cloud and find that several molecules should be readily detectable with the Atacama Large Millimeter Array at Full Science operations.

  19. Supercomplexity in Higher Education Kinesiology

    Science.gov (United States)

    Block, Betty A.; Estes, Steve

    2011-01-01

    This article employs Barnett's (2004) specifications of the aspects that describe the times of "supercomplexity." This term characterizes the challenges universities are facing regarding the expanding and competing forces that are affecting higher education, particularly in the West. Outside forces related to globalization, digital technologies,…

  20. Spirituality and Contemporary Higher Education

    Science.gov (United States)

    Waggoner, Michael D.

    2016-01-01

    Though religion played a central role in the founding of U.S. higher education, over the centuries, its influence was diluted by competing secular emphases. In recent decades, religion has seen a resurgence in academic and co-curricular attention on campuses. In addition, a spirituality not based on religion has gained increasing attention. The…

  1. Disability Studies in Higher Education

    Science.gov (United States)

    Taylor, Steven J.

    2011-01-01

    As a topic of study, disability is not new at institutions of higher education. Psychological and intellectual disabilities have been of interest in psychiatry and psychology at least since the late 1800s and early 1900s. The post-World War II era, in particular, witnessed the rapid expansion of academic programs in special education, vocational…

  2. Higher Education Reform in Romania.

    Science.gov (United States)

    Eisemon, Thomas Owen; Mihailescu, Ioan; Vlasceanu, Lazar; Zamfir, Catalin; Sheehan, John; Davis, Charles H.

    1999-01-01

    Reviews the crisis in Romanian universities since the country's political transition in 1989. Describes the government's strategy for revitalizing the higher education system. Focuses on the proliferation of new public and private universities, the increase of student enrollments in applied social science fields, and the problems of diminishing…

  3. Digital Storytelling in Higher Education

    Science.gov (United States)

    McLellan, Hilary

    2007-01-01

    Digital storytelling is a promising instructional strategy as well as an emerging field of study in higher education. Courses on digital storytelling are offered in communications and creative writing programs at a number of universities. However, the potential for digital storytelling extends far beyond the fields of communication and media…

  4. Mitigating Higher Ed Cyber Attacks

    Science.gov (United States)

    Rogers, Gary; Ashford, Tina

    2015-01-01

    In this presentation we will discuss the many and varied cyber attacks that have recently occurred in the higher ed community. We will discuss the perpetrators, the victims, the impact and how these institutions have evolved to meet this threat. Mitigation techniques and defense strategies will be covered as will a discussion of effective security…

  5. Sabbatical Leaves in Higher Education.

    Science.gov (United States)

    Eberle, August W.; Thompson, Robert E.

    This document presents a status report of various sabbatical leave policies and plans at 386 higher education institutions across the U.S. The report provides information that can serve as a guide for institutions that do not presently provide sabbatical leaves of absence or that can be compared with existing sabbatical leave plans. It was found…

  6. Gender Issues within Higher Education

    Science.gov (United States)

    European Students' Union (NJ1), 2008

    2008-01-01

    This handbook functions as a crown on the European Students' Union's work on gender equality over the past two years. Since the establishment of the Gender Equality Committee, a lot of work has been done to improve gender equality in higher education generally, and in student unions more particularly. This handbook gathers the experiences and…

  7. Project Management in Higher Education

    Science.gov (United States)

    Alpert, Shannon Atkinson

    2011-01-01

    This study identified factors that influenced the use of project management in higher education research projects. Using a qualitative grounded theory approach that included in-depth interviews with assistant professors, the researcher examined how these individuals were using project management processes and tools and factors that enabled,…

  8. A Changing Higher Education Environment.

    Science.gov (United States)

    Sullivan, Eleanor J.

    1997-01-01

    Economics, demographics, technology, and accountability demands are challenging program relevance, tenure, and research in higher education. Universities must have a clear sense of the future and be carefully deliberate about purposes and methods in order to respond to opportunities and serve as a catalyst for new visions. (SK)

  9. Higher Education Litigation: An Overview.

    Science.gov (United States)

    Zirkel, Perry A.

    1989-01-01

    To determine the frequency of reported litigation in higher education, a WESTLAW search of the institutional, employees, and student categories under the topic "Colleges and Universities" was conducted. The institutional cases declined notably in the 1980s while the employee and student cases increased slightly. (MLF)

  10. Higher Education & the Consumer Society.

    Science.gov (United States)

    Knefelcamp, Lee

    1993-01-01

    Higher education is capable of responding constructively to social change, diversification of the student body, and student learning needs. It can do this by integrating itself into the community; focusing on the classroom, not the campus, as the center of learning; and adapting to new roles and structures as needed. (MSE)

  11. Equity, Envy, and Higher Education.

    Science.gov (United States)

    Baum, Sandra R.; Schwartz, Saul

    1986-01-01

    Develops and tests an empirical measure of fairness and envy over access to higher education for 12,000 high school students. Results suggest that, given the existence of current government subsidies, financial barriers do not prevent a significant number of high school graduates from attending college. (Author/TRS)

  12. Optimal admission to higher education

    DEFF Research Database (Denmark)

    Albæk, Karsten

    2016-01-01

    that documents the relevance of theory and illustrates how to apply optimal admission procedures. Indirect gains from optimal admission procedures include the potential for increasing entire cohorts of students' probability of graduating with a higher education degree, thereby increasing the skill level...

  13. Assessing Cyberbullying in Higher Education

    Science.gov (United States)

    Kamali, Ali

    2015-01-01

    This project aims to expose information educators to various aspects of cyberbullying for the purpose of policy development in an environment of higher education. The preponderance of nation-wide research on cyberbullying is concentrated on adolescents; such efforts in college campuses are limited to individual endeavors. Cyberbullying research on…

  14. Transnational Higher Education in Uzbekistan

    Science.gov (United States)

    Sia, E. K.

    2014-01-01

    This paper provides an overview of transnational higher education (THE) in Uzbekistan. It includes a brief account of THE current and future market trends. The data, gathered from a literature search, show that the demand for THE (off-campus) is growing even faster than the demand for international (on-campus) programmes. This paper then provides…

  15. Hypothetical Insurance and Higher Education

    Science.gov (United States)

    Colburn, Ben; Lazenby, Hugh

    2016-01-01

    What level of government subsidy of higher education is justified, in what form, and for what reasons? We answer these questions by applying the hypothetical insurance approach, originally developed by Ronald Dworkin in his work on distributive justice. On this approach, when asking how to fund and deliver public services in a particular domain,…

  16. Stakeholder Relationships in Higher Education

    Science.gov (United States)

    Kettunen, Juha

    2015-01-01

    The purpose of this study is to develop a stakeholder map to describe the most important stakeholders and the process of stakeholder relationships in higher education. According to the perspective of the balanced scorecard, the classification of stakeholders integrates stakeholders into strategic management. Stakeholder maps are essential in…

  17. Higher Education Marketing: A Challenge.

    Science.gov (United States)

    Canterbury, Richard M.

    1999-01-01

    Discusses similarities and differences in the marketing of higher education and other services, especially in regard to marketing to high school students. Considers the importance of the college choice decision, the adolescent's competence to choose wisely in light of promotional efforts, family influences, and the question of what higher…

  18. Social Stratification in Higher Education

    Science.gov (United States)

    Grodsky, Eric; Jackson, Erika

    2009-01-01

    Background/Context: Over the past half century, scholars in a variety of fields have contributed to our understanding of the relationship between higher education and social stratification. We review this literature, highlighting complementarities and inconsistencies. Purpose/Objective/Research Question/Focus of Study: We situate our review of the…

  19. Funding Higher Education in Malaysia

    OpenAIRE

    Kee Kuan Foong

    2008-01-01

    As the higher education system contributes significantly towards sustaining long-term economic growth in Malaysia, adequate funding should be directed to this subsector. Moreover, policies need to be impartial and stringent scholarship selection mechanism be used. Ongoing reforms to enhance the quality of tertiary education may also be important.

  20. Wave equations in higher dimensions

    CERN Document Server

    Dong, Shi-Hai

    2011-01-01

    Higher dimensional theories have attracted much attention because they make it possible to reduce much of physics in a concise, elegant fashion that unifies the two great theories of the 20th century: Quantum Theory and Relativity. This book provides an elementary description of quantum wave equations in higher dimensions at an advanced level so as to put all current mathematical and physical concepts and techniques at the reader’s disposal. A comprehensive description of quantum wave equations in higher dimensions and their broad range of applications in quantum mechanics is provided, which complements the traditional coverage found in the existing quantum mechanics textbooks and gives scientists a fresh outlook on quantum systems in all branches of physics. In Parts I and II the basic properties of the SO(n) group are reviewed and basic theories and techniques related to wave equations in higher dimensions are introduced. Parts III and IV cover important quantum systems in the framework of non-relativisti...

  1. Higher Education and European Regionalism.

    Science.gov (United States)

    Paterson, Lindsay

    2001-01-01

    Speculates about the relationship between two fundamental social changes occurring in Europe: the development of a mass higher education system and the slow decay of the old states that were inherited from the 19th century, eroded from below by various movements for national and regional autonomy, and eroded from above by the growing power and…

  2. Extremal higher spin black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bañados, Máximo [Instituto de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago (Chile); Castro, Alejandra [Institute for Theoretical Physics, University of Amsterdam,Science Park 904, Postbus 94485, Amsterdam, 1090 GL (Netherlands); Faraggi, Alberto [Instituto de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago (Chile); Jottar, Juan I. [Institut für Theoretische Physik, ETH Zürich,Zürich, CH-8093 (Switzerland)

    2016-04-13

    The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require supersymmetry, we exemplify its consequences in the context of sl(3|2)⊕sl(3|2) Chern-Simons theory and show that, as usual, not all extremal solutions preserve supersymmetries. Remarkably, we find in addition that the higher spin setup allows for non-extremal supersymmetric black hole solutions. Furthermore, we discuss our results from the perspective of the holographic duality between sl(3|2)⊕sl(3|2) Chern-Simons theory and two-dimensional CFTs with W{sub (3|2)} symmetry, the simplest higher spin extension of the N=2 super-Virasoro algebra. In particular, we compute W{sub (3|2)} BPS bounds at the full quantum level, and relate their semiclassical limit to extremal black hole or conical defect solutions in the 3d bulk. Along the way, we discuss the role of the spectral flow automorphism and provide a conjecture for the form of the semiclassical BPS bounds in general N=2 two-dimensional CFTs with extended symmetry algebras.

  3. Measuring Urban Carbon Footprint from Carbon Flows in the Global Supply Chain.

    Science.gov (United States)

    Hu, Yuanchao; Lin, Jianyi; Cui, Shenghui; Khanna, Nina Zheng

    2016-06-21

    A global multiregional input-output (MRIO) model was built for eight Chinese cities to track their carbon flows. For in-depth understanding of urban carbon footprint from the perspectives of production, consumption, and trade balance, four kinds of footprints and four redefined measurement indicators were calculated. From the global supply chain, urban carbon inflows from Mainland China were larger than outflows, while the carbon outflows to European, principal North American countries and East Asia were much larger than inflows. With the rapid urbanization of China, Construction was the largest consumer and Utilities was the largest producer. Cities with higher consumption (such as Dalian, Tianjin, Shanghai, and Beijing) should change their consumption patterns, while cities with lower production efficiency (such as Dalian, Shanghai, Ningbo, and Chongqing) should improve their technology. The cities of net carbon consumption tended to transfer carbon emissions out of them by trading in carbon-intensive products, while the cities of net carbon production tended to produce carbon-intensive products for nonlocal consumers. Our results indicated that urban carbon abatement requires not only rational consumption and industrial symbiosis at the city level, but also tighter collaboration along all stages of the global supply chain.

  4. Widespread release of old carbon across the Siberian Arctic echoed by its large rivers

    Directory of Open Access Journals (Sweden)

    Ö. Gustafsson

    2011-06-01

    Full Text Available Over decadal-centennial timescales, only a few mechanisms in the carbon-climate system could cause a massive net redistribution of carbon from land and ocean systems to the atmosphere in response to climate warming. The largest such climate-vulnerable carbon pool is the old organic carbon (OC stored in Arctic permafrost (perennially frozen soils. Climate warming, both predicted and now observed to be the strongest globally in the Eurasian Arctic and Alaska, causes thaw-release of old permafrost carbon from local tundra sites. However, a central challenge for the assessment of the general vulnerability of this old OC pool is to deduce any signal integrating its release over larger scales. Here we examine radiocarbon measurements of molecular soil markers exported by the five Great Russian-Arctic Rivers (Ob, Yenisey, Lena, Indigirka and Kolyma, employed as natural integrators of carbon release processes in their watersheds. The signals held in estuarine surface sediments revealed that average radiocarbon ages of n-alkanes increased east-to-west from 6400 yr BP in Kolyma to 11 400 yr BP in Ob. This is consistent with westwards trends of both warmer climate and more degraded organic matter as indicated by the ratio of high molecular weight (HMW n-alkanoic acids to HMW n-alkanes. The dynamics of Siberian permafrost can thus be probed via the molecular-radiocarbon signal as carried by Arctic rivers. Old permafrost carbon is at present vulnerable to mobilization over continental scales. Climate-induced changes in the radiocarbon fingerprint of released permafrost carbon will likely depend on changes in both permafrost coverage and Arctic soil hydraulics.

  5. EDITORIAL: Deeper, broader, higher, better?

    Science.gov (United States)

    Dobson, Ken

    1998-07-01

    Honorary Editor The standard of educational achievement in England and Wales is frequently criticized, and it seems to be an axiom of government that schools and teachers need to be shaken up, kept on a tight rein, copiously inspected, shamed and blamed as required: in general, subjected to the good old approach of: ' Find out what Johnny is doing and tell him to stop.' About the only exception to this somewhat severe attitude is at A-level, where the standard is simply golden. Often, comparisons are made between the performance of, say, English children and that of their coevals in other countries, with different customs, systems, aims and languages. But there has been a recent comparison of standards at A-level with a non-A-level system of pre-university education, in an English-speaking country that both sends students to English universities and accepts theirs into its own, and is, indeed, represented in the UK government at well above the level expected from its ethnical weighting in the population. This semi-foreign country is Scotland. The conclusions of the study are interesting. Scotland has had its own educational system, with `traditional breadth', and managed to escape much of the centralized authoritarianism that we have been through south of the border. It is interesting to note that, while for the past dozen years or so the trend in A-level Physics entries has been downwards, there has been an increase in the take-up of Scottish `Highers'. Highers is a one-year course. Is its popularity due to its being easier than A-level? Scottish students keen enough to do more can move on to the Certificate of Sixth Year Studies, and will shortly be able to upgrade a Higher Level into an Advanced Higher Level. A comparability study [ Comparability Study of Scottish Qualifications and GCE Advanced Levels: Report on Physics January 1998 (free from SQA)] was carried out by the Scottish Qualifications Authority (SQA) with the aim (amongst others) of helping

  6. Agglomeration defects on irradiated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Steini Moura, Cassio [Faculty of Physics, Pontificia Universidade Catolica do Rio Grande do Sul, 90619-900, Porto Alegre, RS (Brazil); Balzaretti, Naira Maria; Amaral, Livio [Institute of Physics, Universidade Federal do Rio Grande do Sul, C.P.: 15051, 91501-070, Porto Alegre, RS (Brazil); Gribel Lacerda, Rodrigo; Pimenta, Marcos A. [Universidade Federal de Minas Gerais, C.P.: 702, 31270-901, Belo Horizonte, MG (Brazil)

    2012-03-15

    Aligned carbon nanotubes (CNT) were irradiated in the longitudinal and perpendicular directions, with low energy carbon and helium ions in order to observe the formation of defects in the atomic structure. Analysis through Raman spectroscopy and scanning electron microscopy indicated bundle rupture and ion track formation on nanotube bundles. Aligned CNT presented a kind of defect comprising ravine formation and tube agglomeration on top of the substrate. The latter structure is possibly caused by static charge accumulation induced by the incoming ions. Fluence plays a role on the short range order. Higher fluence irradiation transforms CNT into amorphous carbon nanowires.

  7. Agglomeration defects on irradiated carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Cássio Stein Moura

    2012-03-01

    Full Text Available Aligned carbon nanotubes (CNT were irradiated in the longitudinal and perpendicular directions, with low energy carbon and helium ions in order to observe the formation of defects in the atomic structure. Analysis through Raman spectroscopy and scanning electron microscopy indicated bundle rupture and ion track formation on nanotube bundles. Aligned CNT presented a kind of defect comprising ravine formation and tube agglomeration on top of the substrate. The latter structure is possibly caused by static charge accumulation induced by the incoming ions. Fluence plays a role on the short range order. Higher fluence irradiation transforms CNT into amorphous carbon nanowires.

  8. Net carbon flux in organic and conventional olive production systems

    Science.gov (United States)

    Saeid Mohamad, Ramez; Verrastro, Vincenzo; Bitar, Lina Al; Roma, Rocco; Moretti, Michele; Chami, Ziad Al

    2014-05-01

    Agricultural systems are considered as one of the most relevant sources of atmospheric carbon. However, agriculture has the potentiality to mitigate carbon dioxide mainly through soil carbon sequestration. Some agricultural practices, particularly fertilization and soil management, can play a dual role in the agricultural systems regarding the carbon cycle contributing to the emissions and to the sequestration process in the soil. Good soil and input managements affect positively Soil Organic Carbon (SOC) changes and consequently the carbon cycle. The present study aimed at comparing the carbon footprint of organic and conventional olive systems and to link it to the efficiency of both systems on carbon sequestration by calculating the net carbon flux. Data were collected at farm level through a specific and detailed questionnaire based on one hectare as a functional unit and a system boundary limited to olive production. Using LCA databases particularly ecoinvent one, IPCC GWP 100a impact assessment method was used to calculate carbon emissions from agricultural practices of both systems. Soil organic carbon has been measured, at 0-30 cm depth, based on soil analyses done at the IAMB laboratory and based on reference value of SOC, the annual change of SOC has been calculated. Substracting sequestrated carbon in the soil from the emitted on resulted in net carbon flux calculation. Results showed higher environmental impact of the organic system on Global Warming Potential (1.07 t CO2 eq. yr-1) comparing to 0.76 t CO2 eq. yr-1 in the conventional system due to the higher GHG emissions caused by manure fertilizers compared to the use of synthetic foliar fertilizers in the conventional system. However, manure was the main reason behind the higher SOC content and sequestration in the organic system. As a resultant, the organic system showed higher net carbon flux (-1.7 t C ha-1 yr-1 than -0.52 t C ha-1 yr-1 in the conventional system reflecting higher efficiency as a

  9. Amount, composition and seasonality of dissolved organic carbon and nitrogen export from agriculture in contrasting climates

    Science.gov (United States)

    Graeber, Daniel; Meerhof, Mariana; Zwirnmann, Elke; Ovesen, Niels; Gelbrecht, Jörg; Teixeira de Mello, Franco; González-Bergonzoni, Ivan; Jeppesen, Erik; Kronvang, Brian

    2014-05-01

    Agricultural catchments are potentially important but often neglected sources of dissolved organic matter (DOM), of which a large part is dissolved organic carbon (DOC) and nitrogen (DON). DOC is an important source of aquatic microbial respiration and DON may be an important source of nitrogen to aquatic ecosystems. However, there is still a lack of comprehensive studies on the amount, composition and seasonality of DOM export from agricultural catchments in different climates. The aim of our study was to assess the amount, composition and seasonality of DOM in a total of four streams in the wet-temperate and subtropical climate of Denmark and Uruguay, respectively. In each climate, we investigated one stream with extensive agriculture (mostly pasture) and one stream with intensive agriculture (mostly intensively used arable land) in the catchment. We sampled each stream taking grab samples fortnightly for two years and measured DOC and DON concentration, as well as molecular composition by size-exclusion chromatography. We used absorbance, fluorescence and parallel factor analysis to gather additional information on the sources and composition of the DOM. The results were coupled to measurements of precipitation, water temperature, discharge, water residence time and physicochemical data measured at each study site to investigate the effects these environmental variables have on the amount and composition of DOM in the streams. Average annual DOM concentration and seasonality were highest in the stream with intensive agriculture in Uruguay and lowest in the stream with extensive agriculture in Denmark. In all streams, the molecular-size composition of DOC and DON were similar and most DOC and DON were exported as humic substances with low C:N ratio, which indicates high bioavailability. Moreover, DON was of higher relative importance in the Uruguayan streams than in the Danish streams, as can be seen from the lower dissolved inorganic to total dissolved nitrogen

  10. Contributions of weather and fuel mix to recent declines in U.S.energy and carbon intensity

    Energy Technology Data Exchange (ETDEWEB)

    Davis, W. Bart; Sanstad, Alan H.; Koomey, Jonathan G.

    2002-10-20

    A recent (1996-2000) acceleration of declines in energy andcarbon intensity in the U.S. remains largely unexplained. This study usesDivisia decomposition and regression to test two candidate explanations -fuel mix and weather. The Divisia method demonstrates that fuel mix doesnot explain the declines in carbon intensity. The fuel mix, both overalland for electricity generation, became slightly more carbon intensiveover the study period (though the slight trend reversed before the end ofthe period). A regression-based correction to the Divisia indices,accounting for variation in heating- and cooling-degree-days, indicatesthat warmer weather accounts for about 30 percent ofthe total declines.This leaves declines of more than 2 percent per year (and an accelerationof more than 1 percent over previous decade) remaining to beexplained.

  11. Energy efficient solvent regeneration process for carbon dioxide capture

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shaojun; Meyer, Howard S.; Li, Shiguang

    2018-02-27

    A process for removing carbon dioxide from a carbon dioxide-loaded solvent uses two stages of flash apparatus. Carbon dioxide is flashed from the solvent at a higher temperature and pressure in the first stage, and a lower temperature and pressure in the second stage, and is fed to a multi-stage compression train for high pressure liquefaction. Because some of the carbon dioxide fed to the compression train is already under pressure, less energy is required to further compress the carbon dioxide to a liquid state, compared to conventional processes.

  12. Conical refraction and higher microlocalization

    CERN Document Server

    Liess, Otto

    1993-01-01

    The main topic of the book is higher analytic microlocalization and its application to problems of propagation of singularities. The part on higher microlocalization could serve as an introduction to the subject. The results on propagation refer to solutions of linear partial differentialoperators with characteristics of variable multiplicity and are of conical refraction type. The relation and interplay between these results and results or constructions from geometrical optics in crystal theory is discussed with many details. The notes are written foremost for researchers working in microlocal analysis, but it is hoped that they can also be of interest for mathematicians and physicists who work in propagation phenomena from a more classical point of view.

  13. Nonlocal higher order evolution equations

    KAUST Repository

    Rossi, Julio D.

    2010-06-01

    In this article, we study the asymptotic behaviour of solutions to the nonlocal operator ut(x, t)1/4(-1)n-1 (J*Id -1)n (u(x, t)), x ∈ ℝN, which is the nonlocal analogous to the higher order local evolution equation vt(-1)n-1(Δ)nv. We prove that the solutions of the nonlocal problem converge to the solution of the higher order problem with the right-hand side given by powers of the Laplacian when the kernel J is rescaled in an appropriate way. Moreover, we prove that solutions to both equations have the same asymptotic decay rate as t goes to infinity. © 2010 Taylor & Francis.

  14. Charged gravastars in higher dimensions

    Directory of Open Access Journals (Sweden)

    S. Ghosh

    2017-04-01

    Full Text Available We explore possibility to find out a new model of gravastars in the extended D-dimensional Einstein–Maxwell space–time. The class of solutions as obtained by Mazur and Mottola of a neutral gravastar [1,2] have been observed as a competent alternative to D-dimensional versions of the Schwarzschild–Tangherlini black hole. The outer region of the charged gravastar model therefore corresponds to a higher dimensional Reissner–Nordström black hole. In connection to this junction conditions, therefore we have formulated mass and the related Equation of State of the gravastar. It has been shown that the model satisfies all the requirements of the physical features. However, overall observational survey of the results also provide probable indication of non-applicability of higher dimensional approach for construction of a gravastar with or without charge from an ordinary 4-dimensional seed as far as physical ground is concerned.

  15. Charged gravastars in higher dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S., E-mail: shnkghosh122@gmail.com [Department of Physics, Indian Institute of Engineering Science and Technology, B. Garden, Howrah 711103, West Bengal (India); Rahaman, F., E-mail: rahaman@associates.iucaa.in [Department of Mathematics, Jadavpur University, Kolkata 700032, West Bengal (India); Guha, B.K., E-mail: bkguhaphys@gmail.com [Department of Physics, Indian Institute of Engineering Science and Technology, B. Garden, Howrah 711103, West Bengal (India); Ray, Saibal, E-mail: saibal@associates.iucaa.in [Department of Physics, Government College of Engineering and Ceramic Technology, 73 A.C.B. Lane, Kolkata 700010, West Bengal (India)

    2017-04-10

    We explore possibility to find out a new model of gravastars in the extended D-dimensional Einstein–Maxwell space–time. The class of solutions as obtained by Mazur and Mottola of a neutral gravastar have been observed as a competent alternative to D-dimensional versions of the Schwarzschild–Tangherlini black hole. The outer region of the charged gravastar model therefore corresponds to a higher dimensional Reissner–Nordström black hole. In connection to this junction conditions, therefore we have formulated mass and the related Equation of State of the gravastar. It has been shown that the model satisfies all the requirements of the physical features. However, overall observational survey of the results also provide probable indication of non-applicability of higher dimensional approach for construction of a gravastar with or without charge from an ordinary 4-dimensional seed as far as physical ground is concerned.

  16. HUNGARIAN HIGHER EDUTATION-SUSTAINABILITY

    Directory of Open Access Journals (Sweden)

    Éva DARABOS

    2015-12-01

    Full Text Available Nowadays, the sustainability already goes far beyond the aspects of environmental protection; the knowledge and the education are also part of the sustainable development. In the field of education, a condition of realizing the sustainability is that the state should ensure a predictable and stable budget for the operation of institutions. Aim of the treatise, at first, is to examine the fulfilment of Europe 2020 Strategy objective affecting the higher education directly and then, based on statistical data, to present the trend in number of students of the Hungarian higher education and its composition by regions and to examine the change in the budgetary support.In order to retain the sustainability and competitiveness, the state and the institutions should make efforts to harmonise their sources and expenditures and to ensure a predictable, stable financial environment for the sector and its stakeholders.

  17. FACEBOOK COMMUNICATION IN HIGHER EDUCATION

    OpenAIRE

    Emanuela Maria AVRAM

    2014-01-01

    The social networks have been growing steadily in recent years. Facebook, one of the most popular social networks, is a modern means of communication and socialization that has taken lately more ground in higher education becoming an important academic tool in the communication process. Many universities have their own Facebook page, being used by both students and teachers, and creating Facebook groups increasingly facilitates communication with students. Thus, this paper aims to identify th...

  18. IKAR moves to higher energies

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    The measurements of hadron elastic scattering on protons at small angle (WA9 experiment) were extended at higher energies (NA8 experiment by the Clermont Ferrand-Leningrad-Lyon-Uppsala Collaboration). To this purpose the set-up was moved to the beam H8 in the EHN1 Hall of the SPS North Area. The photo shows the ionization chamber measuring the recoil energy (centre). Pierre Sahuc stands on the left.

  19. Genome organization in higher organisms

    OpenAIRE

    Gaillard, Claire; Strauss, Francois

    2005-01-01

    The complexity of higher organisms, which arises in the course of embryonic development from the much simpler fertilized egg, does not emerge by spontaneous generation nor by miracle. Such complexity must somehow be preexistent in the egg. Since the structure of organisms is genetically transmitted, it is DNA itself, the support of genetic information, that encodes this complexity. Here we propose a model of organization of the genome in DNA loops maintained by DNA crossings. In this model DN...

  20. Learning Theories and Higher Education

    OpenAIRE

    Ashworth, Francis; Brennan, Gabriel; Egan, Kathy; Hamilton, Ron; Sáenz, Olalla

    2004-01-01

    This paper offers a number of materials and resources which may be used as teaching aids for introduction-level courses in learning theories, especially those in higher education. The materials were developed during our participation in a postgraduate diploma module on the psychology of learning and learning theories in 2004, as part of the diploma in third-level learning and teaching at the DIT Learning and Teaching Centre.

  1. Designing PLE for Higher Education

    OpenAIRE

    Kroop, Sylvana; Mikroyannidis, Alexander; Wolpers, Martin; Gillet, Denis; Na, Li

    2015-01-01

    In this chapter, the concept of Personal Learning Environment is first refined taken into account recent advances and the experience gathered in a European research project dedicated to responsive open learning environments. A prototypal implementation of a Web 2.0 platform enabling the construction, the sharing, and the repurposing of personal learning environments is then introduced. Participatory design and validation activities carried out in the framework of higher education test beds ai...

  2. Academic Freedom in Higher Education

    Directory of Open Access Journals (Sweden)

    Tokay GEDİKOĞLU

    2013-12-01

    Full Text Available In this study, the concept ‘academic freedom’ is discussed, its implications and value for the academics, institutions of higher education, and the society are focused, and a few suggestions for the Turkish higher education are made. Academic freedom is defined as the freedom of the academic staff to look for and to find the truth in their scientific field, to publish the findings, and to teach these findings to their students without any external intervention. The concept has gained a further definition with inclusion of research activities into academic freedom as part of the reform attempts started in the German higher education in the 19th century. Therefore, academic freedom is at the very core of the missions of the institutions of higher education; that is, teaching-learning and research. On the point of academic staff and their academic activities of the academic freedom, the subjects such as the aim of the course, choosing the teaching materials and textbooks, the lecturer, and the criteria for the measurement and evaluation of the course take place. And he point of research covers the aim of the study, academicians can’t be imposed the involve in an academic and artistic studies that conflict their values and beliefs; researchers should comply with codes of ethical principles and practices during the process of researching; and research outputs should be reported accurately and honestly without any misleading manipulation. Academic freedom does not provide any exemption from accountability in academic activities of the faculty, nor does it provide any right to act against the well-being of the society, current laws and regulations, and codes of ethical principles and practices.

  3. Osteoblast response to nanocrystalline calcium hydroxyapatite depends on carbonate content.

    Science.gov (United States)

    Adams, Brandy R; Mostafa, Amany; Schwartz, Zvi; Boyan, Barbara D

    2014-09-01

    Normal bone mineral is a carbonated-apatite, but there are limited data on the effect of mineral containing carbonate on cell response. We characterized surface chemical compositions of three experimental carbonated hydroxyapatite (CO3(2-) HA) substrates and investigated their effect on osteoblast differentiation. Carbonate was incorporated into the hydroxyapatite powders while phosphate and hydroxyl groups were shown to be reduced by analyzing the chemical composition of the substrate surfaces. CO3(2-) HA powders with increasing carbonate concentrations designated as C1 (3.88%), C2 (4.85%), and C3 (5.82%) were molded, pressed, and fired into 14 mm discs. We observed that calcium phosphate ratios increased monotonically with increasing carbonate content, whereas differentiation of MG63 cells decreased. CO3(2-) HA surfaces also affected factor production. Addition of carbonate caused a 70% reduction in osteoprotegerin (OPG) compared to cultures on pure HA, but the effect of carbonate was not dose-dependent. Low carbonate content reduced VEGF-A by 80%, but higher levels of carbonate reversed this effect in a concentration dependent manner, with the C3 VEFG-A levels approximately twice that of C1 levels. These observations collectively indicate that bone cells are sensitive to carbonate content in bone mineral and the effects of carbonate substitution vary with the outcome being measured. Overall, this study provides a preliminary understanding of how carbonate substitution within hydroxyapatite modulates cellular behavior. © 2013 Wiley Periodicals, Inc.

  4. Novel Mesoporous Carbon Supports for PEMFC Catalysts

    Directory of Open Access Journals (Sweden)

    Dustin Banham

    2015-06-01

    Full Text Available Over the past decade; a significant amount of research has been performed on novel carbon supports for use in proton exchange membrane fuel cells (PEMFCs. Specifically, carbon nanotubes, ordered mesoporous carbon, and colloid imprinted carbons have shown great promise for improving the activity and/or stability of Pt-based nanoparticle catalysts. In this work, a brief overview of these materials is given, followed by an in-depth discussion of our recent work highlighting the importance of carbon wall thickness when designing novel carbon supports for PEMFC applications. Four colloid imprinted carbons (CICs were synthesized using a silica colloid imprinting method, with the resulting CICs having pores of 15 (CIC-15, 26 (CIC-26, 50 (CIC-50 and 80 (CIC-80 nm. These four CICs were loaded with 10 wt. % Pt and then evaluated as oxygen reduction (ORR catalysts for use in proton exchange membrane fuel cells. To gain insight into the poorer performance of Pt/CIC-26 vs. the other three Pt/CICs, TEM tomography was performed, indicating that CIC-26 had much thinner walls (0–3 nm than the other CICs and resulting in a higher resistance (leading to distributed potentials through the catalyst layer during operation. This explanation for the poorer performance of Pt/CIC-26 was supported by theoretical calculations, suggesting that the internal wall thickness of these nanoporous CICs is critical to the future design of porous carbon supports.

  5. Higher prices, higher quality? Evidence from German nursing homes.

    Science.gov (United States)

    Herr, Annika; Hottenrott, Hanna

    2016-02-01

    This study investigates the relationship between prices and quality of 7400 German nursing homes. We use a cross section of public quality reports for all German nursing homes, which had been evaluated between 2010 and 2013 by external institutions. Our analysis is based on multivariate regressions in a two stage least squares framework, where we instrument prices to explain their effect on quality controlling for income, nursing home density, demographics, labour market characteristics, and infrastructure at the regional level. Descriptive analysis shows that prices and quality do not only vary across nursing homes, but also across counties and federal states and that quality and prices correlate positively. Second, the econometric analysis, which accounts for the endogenous relation between negotiated price and reported quality, shows that quality indeed positively depends on prices. In addition, more places in nursing homes per people in need are correlated with both lower prices and higher quality. Finally, unobserved factors at the federal state level capture some of the variation of reported quality across nursing homes. Our results suggest that higher prices increase quality. Furthermore, since reported quality and prices vary substantially across federal states, we conclude that the quality and prices of long-term care facilities may well be compared within federal states but not across. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. The effect of mesoporous carbon modification by nitrogen on its enrichment efficiency of chromate ion: Comparison between N-doped mesoporous carbon and amino grafted mesoporous carbon

    Directory of Open Access Journals (Sweden)

    Moradi S.E.

    2011-01-01

    Full Text Available In the present work, well ordered, N-doped mesoporous carbon (MCN sorbent with uniform mesoporous wall, high surface area and pore volume has been fabricated using the simple polymerization reaction between ethylene diamine and carbon tetrachloride in mesoporous silica media. The structural order and textural properties of nanostructured materials were studied by XRD, elemental analysis, and nitrogen Adsorption-desorption experiment. Adsorption of Chromate over various porous adsorbents such as mesoporous carbon (MC, N-doped mesoporous carbon (MCN, and amino modified mesoporous carbon (AMC was studied from solutions with different concentration, temperature and pH in polar (water solvent. The adsorption isotherms of Chromate were in agreement with Langmuir model, moreover, the uptake capacity of Chromate over MCN was much higher than amino modified mesoporous carbon (AMC and pristine mesoporous carbon adsorbent.

  7. Carbon allocation, sequestration and carbon dioxide mitigation under plantation forests of north western Himalaya, India

    Directory of Open Access Journals (Sweden)

    Bandana Devi

    2013-05-01

    Full Text Available The organic carbon and soils of the world comprise bulk of the terrestrial carbon and serve as a major sink and source of atmospheric carbon. Increasing atmospheric concentrations of green house gases may be mitigated by increasing carbon sequestration in vegetation and soil. The study attempted to estimate biomass production and carbon sequestration potential of different plantation ecosystems in north western Himalaya, India. Biomass, carbon density of biomass, soil, detritus, carbon sequestration and CO2 mitigation potential were studied under different plantation forest ecosystems comprising of eight different tree species: Quercus leucotrichophora, Pinus roxburghii, Acacia catechu, Acacia mollissima, Albizia procera, Alnusnitida, Eucalyptus tereticornis and Ulmus villosa. Above (185.57±48.99tha-1 and below ground (42.47±10.38 tha-1 biomass was maximum in Ulmus villosa. The vegetation carbon density was maxium in Albizia procera(118.37±1.49 tha-1 and minimum (36.50±9.87 tha-1 in Acacia catechu. Soil carbon density was maximum (219.86±10.34 tha-1 in Alnus nitida, and minimum (170.83±20.60 tha-1 in Pinus roxburghii. Detritus was higher in Pinus roxburghii (6.79±2.0 tha-1. Carbon sequestration (7.91±3.4 tha-1 and CO2 mitigation potential (29.09±12.78 tha-1 was maximum in Ulmus villosa. Pearson correlation matrix revealed significant positive relationship of ecosystem carbon with plantation biomass, soil carbon and CO2 mitigation potential. With the emerging threat of climate change, such assessment of forest and soil carbon inventory would allow to devise best land management and policy decisions for sustainable management of fragile hilly ecosystem.

  8. Carbon allocation, sequestration and carbon dioxide mitigation under plantation forests of north western Himalaya, India

    Directory of Open Access Journals (Sweden)

    Bandana Devi

    2013-07-01

    Full Text Available The organic carbon and soils of the world comprise bulk of the terrestrial carbon and serve as amajorsink and source of atmospheric carbon. Increasing atmospheric concentrations of green house gases may be mitigated by increasing carbon sequestration in vegetation and soil. The study attempted to estimate biomass production and carbon sequestration potential of different plantation ecosystems in north western Himalaya, India. Biomass, carbon density of biomass, soil, detritus, carbon sequestration and CO2 mitigation potential were studied underdifferent plantation forest ecosystems comprising of eight different tree species viz. Quercus leucotrichophora, Pinus roxburghii, Acacia catechu, Acacia mollissima, Albizia procera, Alnus nitida, Eucalyptus tereticornis and Ulmus villosa. Above (185.57 ą 48.99 tha-1 and below ground (42.47 ą 10.38 tha-1 biomass was maximum in Ulmus villosa. The vegetation carbon density was maxium in Albizia procera (118.37 ą 1.49 tha-1 and minimum (36.50 ą 9.87 tha-1 in Acacia catechu. Soil carbon density was maximum (219.86ą 10.34 tha-1 in Alnus nitida, and minimum (170.83ą 20.60 tha-1in Pinus roxburghii. Detritus was higher in Pinus roxburghii (6.79 ą 2.0 tha-1. Carbon sequestration (7.91ą 3.4 tha-1 and CO2 mitigation potential (29.09 ą 12.78 tha-1 was maximum in Ulmus villosa. Pearson correlation matrix revealed significant positive relationship of ecosystem carbon with plantation biomass, soil carbon and CO2 mitigation potential. With the emerging threat of climate change, such assessment of forest and soil carbon inventory would allow to devise best land management and policy decisions forsustainable management of fragile hilly ecosystem. 

  9. Seasonal variability of carbon in humic-like matter of ambient size-segregated water soluble organic aerosols from urban background environment

    Science.gov (United States)

    Frka, Sanja; Grgić, Irena; Turšič, Janja; Gini, Maria I.; Eleftheriadis, Konstantinos

    2018-01-01

    Long-term measurements of carbon in HUmic-LIke Substances (HULIS-C) of ambient size-segregated water soluble organic aerosols were performed using a ten-stage low-pressure Berner impactor from December 2014 to November 2015 at an urban background environment in Ljubljana, Slovenia. The mass size distribution patterns of measured species (PM - particulate matter, WSOC - water-soluble organic carbon and HULIS-C) for all seasons were generally tri-modal (primarily accumulation mode) but with significant seasonal variability. HULIS-C was found to have similar distributions as WSOC, with nearly the same mass median aerodynamic diameters (MMADs), except for winter when the HULIS-C size distribution was bimodal. In autumn and winter, the dominant accumulation mode with MMAD at ca. 0.65 μm contributed 83 and 97% to the total HULIS-C concentration, respectively. HULIS-C accounted for a large fraction of WSOC, averaging more than 50% in autumn and 40% in winter. Alternatively, during warmer periods the contributions of ultrafine (27% in summer) and coarse mode (27% in spring) were also substantial. Based on mass size distribution characteristics, HULIS-C was found to be of various sources. In colder seasons, wood burning was confirmed as the most important HULIS source; secondary formation in atmospheric liquid water also contributed significantly, as revealed by the MMADs of the accumulation mode shifting to larger sizes. The distinct difference between the spring and summer ratios of HULIS-C/WSOC in fine particles (ca. 50% in spring, but only 10% in summer) indicated different sources and chemical composition of WSOC in summer (e.g., SOA formation from biogenic volatile organic compounds (BVOCs) via photochemistry). The enlarged amount of HULIS-C in the ultrafine mode in summer suggests that the important contribution was most likely from new particle formation during higher emissions of BVOC due to the vicinity of a mixed deciduous forest; the higher contribution of

  10. Substantial global carbon uptake by cement carbonation

    Science.gov (United States)

    Xi, Fengming; Davis, Steven J.; Ciais, Philippe; Crawford-Brown, Douglas; Guan, Dabo; Pade, Claus; Shi, Tiemao; Syddall, Mark; Lv, Jie; Ji, Lanzhu; Bing, Longfei; Wang, Jiaoyue; Wei, Wei; Yang, Keun-Hyeok; Lagerblad, Björn; Galan, Isabel; Andrade, Carmen; Zhang, Ying; Liu, Zhu

    2016-12-01

    Calcination of carbonate rocks during the manufacture of cement produced 5% of global CO2 emissions from all industrial process and fossil-fuel combustion in 2013. Considerable attention has been paid to quantifying these industrial process emissions from cement production, but the natural reversal of the process--carbonation--has received little attention in carbon cycle studies. Here, we use new and existing data on cement materials during cement service life, demolition, and secondary use of concrete waste to estimate regional and global CO2 uptake between 1930 and 2013 using an analytical model describing carbonation chemistry. We find that carbonation of cement materials over their life cycle represents a large and growing net sink of CO2, increasing from 0.10 GtC yr-1 in 1998 to 0.25 GtC yr-1 in 2013. In total, we estimate that a cumulative amount of 4.5 GtC has been sequestered in carbonating cement materials from 1930 to 2013, offsetting 43% of the CO2 emissions from production of cement over the same period, not including emissions associated with fossil use during cement production. We conclude that carbonation of cement products represents a substantial carbon sink that is not currently considered in emissions inventories.

  11. Global Carbon Budget 2016

    Science.gov (United States)

    Le Quéré, Corinne; Andrew, Robbie M.; Canadell, Josep G.; Sitch, Stephen; Korsbakken, Jan Ivar; Peters, Glen P.; Manning, Andrew C.; Boden, Thomas A.; Tans, Pieter P.; Houghton, Richard A.; Keeling, Ralph F.; Alin, Simone; Andrews, Oliver D.; Anthoni, Peter; Barbero, Leticia; Bopp, Laurent; Chevallier, Frédéric; Chini, Louise P.; Ciais, Philippe; Currie, Kim; Delire, Christine; Doney, Scott C.; Friedlingstein, Pierre; Gkritzalis, Thanos; Harris, Ian; Hauck, Judith; Haverd, Vanessa; Hoppema, Mario; Klein Goldewijk, Kees; Jain, Atul K.; Kato, Etsushi; Körtzinger, Arne; Landschützer, Peter; Lefèvre, Nathalie; Lenton, Andrew; Lienert, Sebastian; Lombardozzi, Danica; Melton, Joe R.; Metzl, Nicolas; Millero, Frank; Monteiro, Pedro M. S.; Munro, David R.; Nabel, Julia E. M. S.; Nakaoka, Shin-ichiro; O'Brien, Kevin; Olsen, Are; Omar, Abdirahman M.; Ono, Tsuneo; Pierrot, Denis; Poulter, Benjamin; Rödenbeck, Christian; Salisbury, Joe; Schuster, Ute; Schwinger, Jörg; Séférian, Roland; Skjelvan, Ingunn; Stocker, Benjamin D.; Sutton, Adrienne J.; Takahashi, Taro; Tian, Hanqin; Tilbrook, Bronte; van der Laan-Luijkx, Ingrid T.; van der Werf, Guido R.; Viovy, Nicolas; Walker, Anthony P.; Wiltshire, Andrew J.; Zaehle, Sönke

    2016-11-01

    .3 ± 0.5 GtC yr-1, ELUC 1.0 ± 0.5 GtC yr-1, GATM 4.5 ± 0.1 GtC yr-1, SOCEAN 2.6 ± 0.5 GtC yr-1, and SLAND 3.1 ± 0.9 GtC yr-1. For year 2015 alone, the growth in EFF was approximately zero and emissions remained at 9.9 ± 0.5 GtC yr-1, showing a slowdown in growth of these emissions compared to the average growth of 1.8 % yr-1 that took place during 2006-2015. Also, for 2015, ELUC was 1.3 ± 0.5 GtC yr-1, GATM was 6.3 ± 0.2 GtC yr-1, SOCEAN was 3.0 ± 0.5 GtC yr-1, and SLAND was 1.9 ± 0.9 GtC yr-1. GATM was higher in 2015 compared to the past decade (2006-2015), reflecting a smaller SLAND for that year. The global atmospheric CO2 concentration reached 399.4 ± 0.1 ppm averaged over 2015. For 2016, preliminary data indicate the continuation of low growth in EFF with +0.2 % (range of -1.0 to +1.8 %) based on national emissions projections for China and USA, and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. In spite of the low growth of EFF in 2016, the growth rate in atmospheric CO2 concentration is expected to be relatively high because of the persistence of the smaller residual terrestrial sink (SLAND) in response to El Niño conditions of 2015-2016. From this projection of EFF and assumed constant ELUC for 2016, cumulative emissions of CO2 will reach 565 ± 55 GtC (2075 ± 205 GtCO2) for 1870-2016, about 75 % from EFF and 25 % from ELUC. This living data update documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this data set (Le Quéré et al., 2015b, a, 2014, 2013). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP_2016).

  12. Disruptive technologies in higher education

    Directory of Open Access Journals (Sweden)

    Michael Flavin

    2012-08-01

    Full Text Available This paper analyses the role of “disruptive” innovative technologies in higher education. In this country and elsewhere, Higher Education Institutions (HEIs have invested significant sums in learning technologies, with Virtual Learning Environments (VLEs being more or less universal, but these technologies have not been universally adopted and used by students and staff. Instead, other technologies not owned or controlled by HEIs are widely used to support learning and teaching. According to Christensen's theory of Disruptive Innovation, these disruptive technologies are not designed explicitly to support learning and teaching in higher education, but have educational potential. This study uses Activity Theory and Expansive Learning to analyse data regarding the impact of disruptive technologies. The data were obtained through a questionnaire survey about awareness and use of technologies, and through observation and interviews, exploring participants’ actual practice. The survey answers tended to endorse Disruptive Innovation theory, with participants establishing meanings for technologies through their use of them, rather than in keeping with a designer's intentions. Observation revealed that learners use a narrow range of technologies to support learning, but with a tendency to use resources other than those supplied by their HEIs. Interviews showed that participants use simple and convenient technologies to support their learning and teaching. This study identifies a contradiction between learning technologies made available by HEIs, and technologies used in practice. There is no evidence to suggest that a wide range of technologies is being used to support learning and teaching. Instead, a small range of technologies is being used for a wide range of tasks. Students and lecturers are not dependent on their HEIs to support learning and teaching. Instead, they self-select technologies, with use weighted towards established brands. The

  13. Higher dimensional discrete Cheeger inequalities

    Directory of Open Access Journals (Sweden)

    Anna Gundert

    2015-01-01

    Full Text Available For graphs there exists a strong connection between spectral and combinatorial expansion properties. This is expressed, e.g., by the discrete Cheeger inequality, the lower bound of which states that $\\lambda(G \\leq h(G$, where $\\lambda(G$ is the second smallest eigenvalue of the Laplacian of a graph $G$ and $h(G$ is the Cheeger constant measuring the edge expansion of $G$. We are interested in generalizations of expansion properties to finite simplicial complexes of higher dimension (or uniform hypergraphs. Whereas higher dimensional Laplacians were introduced already in 1945 by Eckmann, the generalization of edge expansion to simplicial complexes is not straightforward. Recently, a topologically motivated notion analogous to edge expansion that is based on $\\mathbb{Z}_2$-cohomology was introduced by Gromov and independently by Linial, Meshulam and Wallach. It is known that for this generalization there is no direct higher dimensional analogue of the lower bound of the Cheeger inequality. A different, combinatorially motivated generalization of the Cheeger constant, denoted by $h(X$, was studied by Parzanchevski, Rosenthal and Tessler. They showed that indeed $\\lambda(X \\leq h(X$, where $\\lambda(X$ is the smallest non-trivial eigenvalue of the ($(k-1$-dimensional upper Laplacian, for the case of $k$-dimensional simplicial complexes $X$ with complete $(k-1$-skeleton. Whether this inequality also holds for $k$-dimensional complexes with non-com\\-plete$(k-1$-skeleton has been an open question.We give two proofs of the inequality for arbitrary complexes. The proofs differ strongly in the methods and structures employed,and each allows for a different kind of additional strengthening of the original result.

  14. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Non-Fire Carbon Monoxide Deaths Associated with the Use of Consumer Products 2012 Annual Estimates OCTOBER 13, ... Non-Fire Carbon Monoxide Deaths Associated with the Use of Consumer Products 2011 Annual Estimates View All ...

  15. Trading forest carbon - OSU

    Science.gov (United States)

    Issues associate with trading carbon sequestered in forests are discussed. Scientific uncertainties associated with carbon measurement are discussed with respect to proposed accounting procedures. Major issues include: (1) Establishing baselines. (2) Determining additivity from f...

  16. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Center Carbon Monoxide Information Center En Español The Invisible Killer Carbon monoxide, also known as CO, is called the "Invisible Killer" because it's a colorless, odorless, poisonous gas. ...

  17. Carbon Materials Research

    National Research Council Canada - National Science Library

    Hoffman, Wesley P

    2005-01-01

    Carbon-carbon composites have been used by the Air Force and others for over 25 years in a variety of thermostructural applications including rocket propulsion, re-entry, hypersonics and aircraft brakes...

  18. Preparing to Capture Carbon

    National Research Council Canada - National Science Library

    Daniel P. Schrag

    2007-01-01

    .... Scientific and economic challenges still exist, but none are serious enough to suggest that carbon capture and storage will not work at the scale required to offset trillions of tons of carbon...

  19. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  20. Biomass Carbon Stock

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Biomass carbon includes carbon stored in above- and below-ground live plant components (such as leaf, branch, stem and root) as well as in standing and down dead...

  1. Soil Organic Carbon Stock

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Soil organic carbon (SOC) is the carbon held within soil organic constituents (i.e., products produced as dead plants and animals decompose and the soil microbial...

  2. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  3. Innovations in higher medical education

    Directory of Open Access Journals (Sweden)

    Popkov V.M.

    2014-03-01

    Full Text Available The article is devoted to the innovations in the higher medical education. Particular attention in this sphere is paid to the detailed analysis of the subject as a mechanism of cognition and psycho-emotional aspect. It should be noticed that the development of the university education demands the integration of functional systems to study the general medicine and the art of healing. In conclusion it has been found out that the new methodological approach is necessary to bring the teacher closer to the subject particularly to integrate the relation of the opposites.

  4. Asymptotic vacua with higher derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Cotsakis, Spiros, E-mail: skot@aegean.gr [Department of Mathematics, American University of the Middle East, P.O. Box 220 Dasman, 15453 (Kuwait); Kadry, Seifedine, E-mail: Seifedine.Kadry@aum.edu.kw [Department of Mathematics, American University of the Middle East, P.O. Box 220 Dasman, 15453 (Kuwait); Kolionis, Georgios, E-mail: gkolionis@aegean.gr [Research group of Geometry, Dynamical Systems and Cosmology, University of the Aegean, Karlovassi 83200, Samos (Greece); Tsokaros, Antonios, E-mail: atsok@aegean.gr [Research group of Geometry, Dynamical Systems and Cosmology, University of the Aegean, Karlovassi 83200, Samos (Greece)

    2016-04-10

    We study limits of vacuum, isotropic universes in the full, effective, four-dimensional theory with higher derivatives. We show that all flat vacua as well as general curved ones are globally attracted by the standard, square root scaling solution at early times. Open vacua asymptote to horizon-free, Milne states in both directions while closed universes exhibit more complex logarithmic singularities, starting from initial data sets of a possibly smaller dimension. We also discuss the relation of our results to the asymptotic stability of the passage through the singularity in ekpyrotic and cyclic cosmologies.

  5. Playful learning in higher education

    DEFF Research Database (Denmark)

    Nørgård, Rikke Toft; Toft-Nielsen, Claus; Whitton, Nicola

    2017-01-01

    learning, drawing on notions of signature pedagogies, field literature, and two qualitative studies on learner conceptions of enjoyment and reasons for disengagement. We highlight the potential of this approach to invite a different mind-set and environment, providing a formative space in which failure......Increased focus on quantifiable performance and assessment in higher education is creating a learning culture characterised by fear of failing, avoidance of risk, and extrinsic goal-oriented behaviours. In this article, we explore possibilities of a more playful approach to teaching and learning...... is not only encouraged, but a necessary part of the learning paradigm....

  6. Cellulose biosynthesis in higher plants

    Directory of Open Access Journals (Sweden)

    Krystyna Kudlicka

    2014-01-01

    Full Text Available Knowledge of the control and regulation of cellulose synthesis is fundamental to an understanding of plant development since cellulose is the primary structural component of plant cell walls. In vivo, the polymerization step requires a coordinated transport of substrates across membranes and relies on delicate orientations of the membrane-associated synthase complexes. Little is known about the properties of the enzyme complexes, and many questions about the biosynthesis of cell wall components at the cell surface still remain unanswered. Attempts to purify cellulose synthase from higher plants have not been successful because of the liability of enzymes upon isolation and lack of reliable in vitro assays. Membrane preparations from higher plant cells incorporate UDP-glucose into a glucan polymer, but this invariably turns out to be predominantly β -1,3-linked rather than β -1,4-linked glucans. Various hypotheses have been advanced to explain this phenomenon. One idea is that callose and cellulose-synthase systems are the same, but cell disruption activates callose synthesis preferentially. A second concept suggests that a regulatory protein as a part of the cellulose-synthase complex is rapidly degraded upon cell disruption. With new methods of enzyme isolation and analysis of the in vitro product, recent advances have been made in the isolation of an active synthase from the plasma membrane whereby cellulose synthase was separated from callose synthase.

  7. Poly(urethane–carbonate)s from Carbon Dioxide

    KAUST Repository

    Chen, Zuliang

    2017-03-09

    A one-pot, two-step protocol for the direct synthesis of polyurethanes containing few carbonate linkages through polycondensation of diamines, dihalides, and CO2 in the presence of Cs2CO3 and tetrabutylammonium bromide is described. The conditions were optimized by studying the polycondensation of CO2 with 1,6-hexanediamine and 1,4-dibromobutane as model monomers. Then, various diamines and dihalides were tested under optimal conditions. Miscellaneous samples of such carbonate-containing polyurethanes exhibiting molar masses from 6000 to 22 000 g/mol (GPC) and yields higher than 85% were obtained. The thermal properties of such polyurethanes were unveiled by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA): they were found very similar to those of traditional polyurethanes obtained by diisocyanates + diols polycondensation.

  8. Synthesis of dimethyl carbonate in supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    D. Ballivet-Tkatchenko

    2006-03-01

    Full Text Available The reactivity of carbon dioxide with methanol to form dimethyl carbonate was studied in the presence of the n-butylmethoxytin compounds n-Bu3SnOCH3, n-Bu2Sn(OCH32 , and [n-Bu2(CH3OSn]2 O. The reaction occurred under solventless conditions at 423 K and was produced by an increase in CO2 pressure. This beneficial effect is primarily attributed to phase behavior. The mass transfer under liquid-vapor biphasic conditions was not limiting when the system reached the supercritical state for a CO2 pressure higher than 16 MPa. Under these conditions, CO2 acted as a reactant and a solvent.

  9. Carbon Goes To…

    Science.gov (United States)

    Savasci, Funda

    2014-01-01

    The purposes of this activity are to help middle school students understand the carbon cycle and realize how human activities affect the carbon cycle. This activity consists of two parts. The first part of the activity focuses on the carbon cycle, especially before the Industrial Revolution, while the second part of the activity focuses on how…

  10. TWIN CARBON ARC TORCH

    African Journals Online (AJOL)

    its predominate applications in heating, brazing, and welding have been supplanted by the highly developed oxyacetylene torch. As seen in Fig. l, the twin carbon arc torch (henceforth referred to in this article as simply the carbon-arc torch) consists of a hand held apparatus made of two ('twin') carbon or graphite electrodes ...

  11. Carbon nanotube quantum dots

    NARCIS (Netherlands)

    Sapmaz, S.

    2006-01-01

    Low temperature electron transport measurements on individual single wall carbon nanotubes are described in this thesis. Carbon nanotubes are small hollow cylinders made entirely out of carbon atoms. At low temperatures (below ~10 K) finite length nanotubes form quantum dots. Because of its small

  12. Protolytic carbon film technology

    Energy Technology Data Exchange (ETDEWEB)

    Renschler, C.L.; White, C.A.

    1996-04-01

    This paper presents a technique for the deposition of polyacrylonitrile (PAN) on virtually any surface allowing carbon film formation with only the caveat that the substrate must withstand carbonization temperatures of at least 600 degrees centigrade. The influence of processing conditions upon the structure and properties of the carbonized film is discussed. Electrical conductivity, microstructure, and morphology control are also described.

  13. Carbon/Carbon Pistons for Internal Combustion Engines

    Science.gov (United States)

    Taylor, A. H.

    1986-01-01

    Carbon/carbon piston performs same function as aluminum pistons in reciprocating internal combustion engines while reducing weight and increasing mechanical and thermal efficiencies of engine. Carbon/carbon piston concept features low piston-to-cylinder wall clearance - so low piston rings and skirts unnecessary. Advantages possible by negligible coefficient of thermal expansion of carbon/carbon.

  14. Adaptability of activated carbon from palm oil kernel shell in the development of brake friction materials

    Science.gov (United States)

    Talib, R. J.; Amri, M. H.; Selamat, M. A.; Basri, M. Hisyam; Ismail, N. I.; Sulaiman, Z. S.; Jumahat, A.

    2017-12-01

    Four friction material formulations composed of binder, reinforcing fiber, friction modifier and filler have been prepared through powder metallurgy route. The objective of this study is to investigate the possibility of palm oil kernel shell (PKS carbon) to replace the commercial carbon in the fabrication of brake friction materials. Sample H and HB are composed of the same vol. % of ingredients, except that sample H was utilizing commercial carbon (C Carbon) while sample HB was utilizing activated carbon from PKS carbon as their carbon ingredient. Selecting sample HB as based formulation, vol. % of PKS carbon was decreased by 50 % (sample HA) and increased by 50 % (sample HC). The other ingredients in the compositions are proportionally decreased and increased, accordingly. The samples were examined for their porosity, hardness, COF and thickness loss. The three samples which composed of PKS carbon had higher COF than sample which composed of commercial carbon. However, their thickness loss is higher than sample which composed of commercial carbon, particularly sample HC which composed of highest vol. % of PKS carbon. It was observed that sample HB which composed of 20 vol. % of PKS recorded the highest COF and slightly higher thickness loss than sample composed of commercial carbon. Thus, it could be postulated that PKS carbon can be used to replace the commercial carbon in developing a new brake friction material with the best formulation containing 20 vol. % PKS.

  15. Gravitating multidefects from higher dimensions

    CERN Document Server

    Giovannini, Massimo

    2007-01-01

    Warped configurations admitting pairs of gravitating defects are analyzed. After devising a general method for the construction of multidefects, specific examples are presented in the case of higher-dimensional Einstein-Hilbert gravity. The obtained profiles describe diverse physical situations such as (topological) kink-antikink systems, pairs of non-topological solitons and bound configurations of a kink and of a non-topological soliton. In all the mentioned cases the geometry is always well behaved (all relevant curvature invariants are regular) and tends to five-dimensional anti-de Sitter space-time for large asymptotic values of the bulk coordinate. Particular classes of solutions can be generalized to the framework where the gravity part of the action includes, as a correction, the Euler-Gauss-Bonnet combination. After scrutinizing the structure of the zero modes, the obtained results are compared with conventional gravitating configurations containing a single topological defect.

  16. What are Higher Psychological Functions?

    Science.gov (United States)

    Toomela, Aaro

    2016-03-01

    The concept of Higher Psychological Functions (HPFs) may seem to be well know in psychology today. Yet closer analysis reveals that HPFs are either not defined at all or if defined, then by a set of characteristics not justified theoretically. It is not possible to determine whether HPFs exist or not, unless they are defined. Most commonly the idea of HPFs is related to Vygotsky's theory. According to him, HPFs are: (1) psychological systems, (2) developing from natural processes, (3) mediated by symbols, (4) forms of psychological cooperation, which are (5) internalized in the course of development, (6) products of historical development, (7) conscious and (8) voluntary (9) active forms of adaptation to the environment, (10) dynamically changing in development, and (11) ontogeny of HPFs recapitulates cultural history. In this article these characteristics are discussed together with the relations among them. It is concluded that HPFs are real psychological phenomena.

  17. Library assessment in higher education

    CERN Document Server

    Matthews, Joseph R

    2015-01-01

    Academic libraries are increasingly being asked to demonstrate their value as one of many units on campus, but determining the outcomes of an academic library within the context of its collegiate setting is challenging. This book explains and clarifies the practice of assessment in academic institutions, enabling library managers to better understand and explain the impact of the library on student learning outcomes, teaching effectiveness, and research productivity. Providing essential information for all college and university librarians, this volume discusses and summarizes the outcomes of research that has been conducted to investigate assessment within the context of higher education. This updated second edition incorporates additional research, examines new trends, and covers groundbreaking advances in digital assessment tools as well as the changes in the amount and forms of data utilized in the assessment process. The chapters address assessment from a campus setting and present data that demonstrate...

  18. Higher dimensional defects in cosmology

    Science.gov (United States)

    Ramadhan, Handhika Satrio

    Extra dimensions seem to be an important ingredient for unification of gravity with quantum field theory. Our best candidate of quantum gravity, superstring theory, requires ten-dimensional space-time for mathematical consistency. However, since our world appears four-dimensional there must be a mechanism that "hides" extra dimensions so that we do not experience them at low energy scale. There are several methods in literature for concealing extra dimensions from our naked eye. In this thesis we only focus on two of them: braneworld scenario and flux compactification, both of which require the existence of the bulk fields. This thesis investigates the role topological defects can play as bulk fields in higher-dimensional cosmology with different asymptotic topology. The first part deals with the non-singular braneworld: Skyrme branes and its higher dimensional generalizations. We show how these defects regularize the naked singularity around the core while at the same time approach the same flat-asymptotic behavior as the known thin-wall solutions. The second part is devoted to study an exotic transition, tunneling to (and from) nothing, in a landscape where the space-time vacua are direct products of X4 x S2 , with X4 can be: anti-de Sitter ( AdS4), Minkowski (M4), or de Sitter (dS4). The tunneling is mediated by instanton solutions, via bubble nucleation. The bubble wall is smooth and magnetically-charged, and we show that this can be accomplished by having solitonic brane possessing magnetic charge, i.e., magnetic-monopole branes.

  19. Sustainability of higher educational buildings

    Directory of Open Access Journals (Sweden)

    Aboulnaga Mohsen

    2016-01-01

    Full Text Available Despite greenhouse gases (GHG emissions of Egypt represent nearly 1 percent of the World's GHG emissions, but according to IPCCC, Egypt is one of the nations that will be heavily affected by the impact of climate change risks. The global CO2 emissions from different sectors, buildings are forming the highest portion (about 5.5 GtCO2-eq. Electricity consumption in public buildings, including administrative, educational and health buildings (9 percent is the 2nd largest type after residential buildings (40 percent. The electrical energy per person in Egypt has increased from 1245 kWh in 2001/2002 to 1950 kWh in 2012/2013; an increase of 57 percent. This resulted in a colossal amount of CO2 emitted into the atmosphere. Thus, improving energy performance in residential and higher education buildings will have a significant impact on the reduction of electrical energy use, improve recourses efficiency and the nation's economic growth and footprint. Energy consumption in education buildings depends, mainly on the building's activities, time of use and influx of visitors and students and academic staff as well as the academic terms whether in winter summer. Retrofitting measures are important to reduce energy consumption in higher educational buildings and cooling requirements in hot climate. One of the most important measures in the retrofitting process of the building envelop, including its roof are mainly glazing type and characteristics, and walls’ thermal insulation. This paper addresses sustainability measures of the Faculty of Engineering Campus – Department of Architectural Engineering building at Cairo University, Egypt. The objective is to set the baseline assessment of the building’ energy use and compared it with its energy performance after retrofitting measures and simulation. Results show that applying these retrofitting measures; energy use has been reduced by 15 percent from the baseline (BAU energy use of an average of 14.6

  20. Modelling carbon overconsumption and the formation of extracellular particulate organic carbon

    Directory of Open Access Journals (Sweden)

    C. Völker

    2007-07-01

    Full Text Available During phytoplankton growth a fraction of dissolved inorganic carbon (DIC assimilated by phytoplankton is exuded in the form of dissolved organic carbon (DOC, which can be transformed into extracellular particulate organic carbon (POC. A major fraction of extracellular POC is associated with carbon of transparent exopolymer particles (TEP; carbon content = TEPC that form from dissolved polysaccharides (PCHO. The exudation of PCHO is linked to an excessive uptake of DIC that is not directly quantifiable from utilisation of dissolved inorganic nitrogen (DIN, called carbon overconsumption. Given these conditions, the concept of assuming a constant stoichiometric carbon-to-nitrogen (C:N ratio for estimating new production of POC from DIN uptake becomes inappropriate. Here, a model of carbon overconsumption is analysed, combining phytoplankton growth with TEPC formation. The model describes two modes of carbon overconsumption. The first mode is associated with DOC exudation during phytoplankton biomass accumulation. The second mode is decoupled from algal growth, but leads to a continuous rise in POC while particulate organic nitrogen (PON remains constant. While including PCHO coagulation, the model goes beyond a purely physiological explanation of building up carbon rich particulate organic matter (POM. The model is validated against observations from a mesocosm study. Maximum likelihood estimates of model parameters, such as nitrogen- and carbon loss rates of phytoplankton, are determined. The optimisation yields results with higher rates for carbon exudation than for the loss of organic nitrogen. It also suggests that the PCHO fraction of exuded DOC was 63±20% during the mesocosm experiment. Optimal estimates are obtained for coagulation kernels for PCHO transformation into TEPC. Model state estimates are consistent with observations, where 30% of the POC increase was attributed to TEPC formation. The proposed model is of low complexity and is

  1. Global Carbon Budget 2016

    Science.gov (United States)

    Quéré, Corinne Le; Andrew, Robbie M.; Canadell, Josep G.; Sitch, Stephen; Korsbakken, Jan Ivar; Peters, Glen P.; Manning, Andrew C.; Boden, Thomas A.; Tans, Pieter P.; Houghton, Richard A.; hide 12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170008485_hide">

    2016-01-01

    .3+/-0.5 GtC/yr, ELUC 1.0+/-0.5 GtC/yr,GATM 4.5+/-0.1 GtC/yr, SOCEAN 2.6+/-0.5 GtC/yr, and SLAND 3.1+/-0.9 GtC/yr. For year 2015 alone, the growth in EFF was approximately zero and emissions remained at 9.9+/-0.5 GtC/yr, showing a slowdown in growth of these emissions compared to the average growth of 1.8/yr that took place during 2006-2015.Also, for 2015, ELUC was 1.3+/-0.5 GtC/yr, GATM was 6.3+/-0.2 GtC/yr, SOCEAN was 3.0+/-0.5 GtC/yr, and SLAND was 1.9+/-0.9 GtC/yr. GATM was higher in 2015 compared to the past decade (2006-2015), reflecting a smaller SLAND for that year. The global atmospheric CO2 concentration reached 399.4+/-0.1 ppm averaged over 2015. For 2016, preliminary data indicate the continuation of low growth in EFF with +0.2% (range of -1.0 to +1.8% ) based on national emissions projections for China and USA, and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. In spite of the low growth of EFF in 2016, the growth rate in atmospheric CO2 concentration is expected to be relatively high because of the persistence of the smaller residual terrestrial sink (SLAND) in response to El Nino conditions of 2015-2016. From this projection of EFF and assumed constant ELUC for 2016, cumulative emissions of CO2 will reach 565+/-55 GtC (2075+/-205 GtCO2) for 1870-2016, about 75% from EFF and 25% from ELUC. This living data update documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this data set.

  2. Past and prospective carbon stocks in forests of northern Wisconsin: a report from the Chequamegon-Nicolet National Forest Climate Change Response Framework

    Science.gov (United States)

    Richard Birdsey; Yude Pan; Maria Janowiak; Susan Stewart; Sarah Hines; Linda Parker; Stith Gower; Jeremy Lichstein; Kevin McCullough; Fangmin Zhang; Jing Chen; David Mladenoff; Craig Wayson; Chris. Swanston

    2014-01-01

    This report assesses past and prospective carbon stocks for 4.5 million ha of forest land in northern Wisconsin, including a baseline assessment and analysis of the impacts of disturbance and management on carbon stocks. Carbon density (amount of carbon stock per unit area) averages 237 megagrams (Mg) per ha, with the National Forest lands having slightly higher carbon...

  3. Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

    Directory of Open Access Journals (Sweden)

    M. Schobben

    2017-11-01

    Full Text Available Bulk-carbonate carbon isotope ratios are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorganic carbon. However, bulk-carbonate rock is also prone to incorporate diagenetic signals. The aim of the present study is to disentangle primary trends from diagenetic signals in carbon isotope records which traverse the Permian–Triassic boundary in the marine carbonate-bearing sequences of Iran and South China. By pooling newly produced and published carbon isotope data, we confirm that a global first-order trend towards depleted values exists. However, a large amount of scatter is superimposed on this geochemical record. In addition, we observe a temporal trend in the amplitude of this residual δ13C variability, which is reproducible for the two studied regions. We suggest that (sub-sea-floor microbial communities and their control on calcite nucleation and ambient porewater dissolved inorganic carbon δ13C pose a viable mechanism to induce bulk-rock δ13C variability. Numerical model calculations highlight that early diagenetic carbonate rock stabilization and linked carbon isotope alteration can be controlled by organic matter supply and subsequent microbial remineralization. A major biotic decline among Late Permian bottom-dwelling organisms facilitated a spatial increase in heterogeneous organic carbon accumulation. Combined with low marine sulfate, this resulted in varying degrees of carbon isotope overprinting. A simulated time series suggests that a 50 % increase in the spatial scatter of organic carbon relative to the average, in addition to an imposed increase in the likelihood of sampling cements formed by microbial calcite nucleation to 1 out of 10 samples, is sufficient to induce the

  4. Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

    Science.gov (United States)

    Schobben, Martin; van de Velde, Sebastiaan; Gliwa, Jana; Leda, Lucyna; Korn, Dieter; Struck, Ulrich; Vinzenz Ullmann, Clemens; Hairapetian, Vachik; Ghaderi, Abbas; Korte, Christoph; Newton, Robert J.; Poulton, Simon W.; Wignall, Paul B.

    2017-11-01

    Bulk-carbonate carbon isotope ratios are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorganic carbon. However, bulk-carbonate rock is also prone to incorporate diagenetic signals. The aim of the present study is to disentangle primary trends from diagenetic signals in carbon isotope records which traverse the Permian-Triassic boundary in the marine carbonate-bearing sequences of Iran and South China. By pooling newly produced and published carbon isotope data, we confirm that a global first-order trend towards depleted values exists. However, a large amount of scatter is superimposed on this geochemical record. In addition, we observe a temporal trend in the amplitude of this residual δ13C variability, which is reproducible for the two studied regions. We suggest that (sub-)sea-floor microbial communities and their control on calcite nucleation and ambient porewater dissolved inorganic carbon δ13C pose a viable mechanism to induce bulk-rock δ13C variability. Numerical model calculations highlight that early diagenetic carbonate rock stabilization and linked carbon isotope alteration can be controlled by organic matter supply and subsequent microbial remineralization. A major biotic decline among Late Permian bottom-dwelling organisms facilitated a spatial increase in heterogeneous organic carbon accumulation. Combined with low marine sulfate, this resulted in varying degrees of carbon isotope overprinting. A simulated time series suggests that a 50 % increase in the spatial scatter of organic carbon relative to the average, in addition to an imposed increase in the likelihood of sampling cements formed by microbial calcite nucleation to 1 out of 10 samples, is sufficient to induce the observed signal of carbon

  5. Carbon dioxide adsorption in chemically activated carbon from sewage sludge.

    Science.gov (United States)

    de Andrés, Juan Manuel; Orjales, Luis; Narros, Adolfo; de la Fuente, María del Mar; Encarnación Rodríguez, María

    2013-05-01

    In this work, sewage sludge was used as precursor in the production of activated carbon by means of chemical activation with KOH and NaOH. The sludge-based activated carbons were investigated for their gaseous adsorption characteristics using CO2 as adsorbate. Although both chemicals were effective in the development of the adsorption capacity, the best results were obtained with solid NaOH (SBA(T16)). Adsorption results were modeled according to the Langmuir and Freundlich models, with resulting CO2 adsorption capacities about 56 mg/g. The SBA(T16) was characterized for its surface and pore characteristics using continuous volumetric nitrogen gas adsorption and mercury porosimetry. The results informed about the mesoporous character of the SBA(T16) (average pore diameter of 56.5 angstroms). The Brunauer-Emmett-Teller (BET) surface area of the SBA(T16) was low (179 m2/g) in comparison with a commercial activated carbon (Airpel 10; 1020 m2/g) and was mainly composed of mesopores and macropores. On the other hand, the SBA(T16) adsorption capacity was higher than that of Airpel 10, which can be explained by the formation of basic surface sites in the SBA(T16) where CO2 experienced chemisorption. According to these results, it can be concluded that the use of sewage-sludge-based activated carbons is a promising option for the capture of CO2. Adsorption methods are one of the current ways to reduce CO2 emissions. Taking this into account, sewage-sludge-based activated carbons were produced to study their CO2 adsorption capacity. Specifically, chemical activation with KOH and NaOH of previously pyrolyzed sewage sludge was carried out. The results obtained show that even with a low BET surface area, the adsorption capacity of these materials was comparable to that of a commercial activated carbon. As a consequence, the use of sewage-sludge-based activated carbons is a promising option for the capture of CO2 and an interesting application for this waste.

  6. [Paradigm shift in higher education].

    Science.gov (United States)

    Csóka, Mária

    2009-08-30

    The fast changes that took place in the last quarter of the 20th century made the professionals dealing with pedagogy realize that our school system followed the economical changes in terms of training supply and the matter of education very slowly, if at all; let alone the educational methods. We had to realize that the maintaining of this conservative system is not rational, education has become the most important part of the globalisational competition and the key to the 21st century is learning. Accordingly, the spatial and temporal expenditure of education has become a new trend, namely lifelong learning (LLL). The social needs on education have increased, the expectations of economy and employers have changed: knowledge has become the fund of competitiveness. In this process, universities have got an accentuated role: in addition to being the place of undergraduate training they have become the site of postgraduate courses for the increasing graduate adult masses. Therefore, reform processes have started in a number of European countries in the nineties. The Bologna Declaration signed on 19th June 1999 set a common direction for these reforms, with its signatories aiming to establish a standard European Higher Education Area with harmonized and comparable educational systems by 2010. However, the administrative change itself is not enough to reach the goals; a formal innovation has to be followed by a reform of the contents which means reformation of higher education. In recent years, Hungarian colleges and universities have worked out their educational programs that are suitable for the new structure; it is only the new educational programs that started from 1st September 2006. The author determines the most important parts of the reform of the training system of Semmelweis University Faculty of Health Sciences, which are the following: redrawing of the training philosophy and paradigm, the reform of the training structure of macro level (cognition

  7. Predicting molybdenum toxicity to higher plants: Influence of soil properties

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Curdy, R. [Laboratory for Environmental Biotechnology (LBE), Swiss Federal Institute of Technology Lausanne (EPFL) Station 6 CH, 1015 Lausanne (Switzerland); Zhao, F.J. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2010-10-15

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED{sub 50}) of Mo in different soils, explaining > 65% of the variance in ED{sub 50} for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

  8. Chromosomal replicons of higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Van' t Hof, J.

    1987-03-16

    This brief discussion of replicons of higher plants offers a glimpse into the properties of chromosomal DNA replication. It gives evidence that the S phase of unrelated plant species is comprised of temporally ordered replicon families that increase in number with genome size. This orderly process, which assures a normal inheritance of genetic material to recipient daughter cells, is maintained at the level of replicon clusters by two mutually exclusive mechanisms, one involving the rate at which single replicons replicate their allotment of DNA, and another by means of the tempo-pause. The same two mechanisms are used by cells to alter the pattern of chromosomal DNA replication just prior to and during normal development. Both mechanisms are genetically determined and produce genetic effects when disturbed of disrupted by additional non-conforming DNAs. Further insight into how these two mechanisms operate requires more molecular information about the nature of replicons and the factors that govern when a replicon family replicates. Plant material is a rich and ideal source for this information just awaiting exploitation. 63 refs.

  9. Resilience and Higher Order Thinking

    Directory of Open Access Journals (Sweden)

    Ioan Fazey

    2010-09-01

    Full Text Available To appreciate, understand, and tackle chronic global social and environmental problems, greater appreciation of the importance of higher order thinking is required. Such thinking includes personal epistemological beliefs (PEBs, i.e., the beliefs people hold about the nature of knowledge and how something is known. These beliefs have profound implications for the way individuals relate to each other and the world, such as how people understand complex social-ecological systems. Resilience thinking is an approach to environmental stewardship that includes a number of interrelated concepts and has strong foundations in systemic ways of thinking. This paper (1 summarizes a review of educational psychology literature on PEBs, (2 explains why resilience thinking has potential to facilitate development of more sophisticated PEBs, (3 describes an example of a module designed to teach resilience thinking to undergraduate students in ways conducive to influencing PEBs, and (4 discusses a pilot study that evaluates the module's impact. Theoretical and preliminary evidence from the pilot evaluation suggests that resilience thinking which is underpinned by systems thinking has considerable potential to influence the development of more sophisticated PEBs. To be effective, however, careful consideration of how resilience thinking is taught is required. Finding ways to encourage students to take greater responsibility for their own learning and ensuring close alignment between assessment and desired learning outcomes are particularly important.

  10. Benchmarking in Czech Higher Education

    Directory of Open Access Journals (Sweden)

    Plaček Michal

    2015-12-01

    Full Text Available The first part of this article surveys the current experience with the use of benchmarking at Czech universities specializing in economics and management. The results indicate that collaborative benchmarking is not used on this level today, but most actors show some interest in its introduction. The expression of the need for it and the importance of benchmarking as a very suitable performance-management tool in less developed countries are the impetus for the second part of our article. Based on an analysis of the current situation and existing needs in the Czech Republic, as well as on a comparison with international experience, recommendations for public policy are made, which lie in the design of a model of a collaborative benchmarking for Czech economics and management in higher-education programs. Because the fully complex model cannot be implemented immediately – which is also confirmed by structured interviews with academics who have practical experience with benchmarking –, the final model is designed as a multi-stage model. This approach helps eliminate major barriers to the implementation of benchmarking.

  11. Social Development and Higher Education

    Directory of Open Access Journals (Sweden)

    Carolina España-Chavarría

    2011-11-01

    Full Text Available This essay has as its main objective to reflect on the duty of the Costa Rican public university and its responsibility to educate in order to foster social development, which is understood as one of the multiple challenges that the higher education faces due to the demands imposed on the operation of knowledge in the present and the relation of such demands with independent knowledge development. In addition, a defense is made of some issues that have been approached weakly in previous studies, issues that become part of the essential elements for promoting a meaningful and functional education that has social impact, elements such as the following: a Ethics in the organization, b The university’s self-education, c The effect of curricular policies on the practices being promoted, d The transformation of the teaching culture to improve practice, and e The construction of knowledge on which to base criteria, decision making, problem solving and the development of life projects.

  12. Carbon/Carbon for satellite applications

    Science.gov (United States)

    Meftah, M.; Lee, S.; Irbah, A.; Ostergren, S.

    2011-06-01

    Carbon/Carbon has many attributes that make it an attractive material for satellite applications. It is low in density, is dimensionally stable under a wide variety of conditions, has very low thermal expansion, is relatively low in cost, and is a mature technology. Moreover, the material is flexible enough to enable the designer to select such variables as fiber type, fabric architecture, fiber volume, and high temperature processing and thus custom tailor the physical and mechanical properties to his specific requirements. A wide range of properties are available - densities from 1.5 to 1.9 g/cm3, room temperature Coefficients of Thermal Expansion (CTE) from -0.3x10-6to -1.3x10-6/K, room temperature thermal conductivities from 7 to 210 W/m.K, and modulus from 60 to 190 GPa. A new type of structure developed by CNRS on the space instrument SODISM uses Carbon/Carbon.

  13. Interannual Variations of the Carbon Footprint and Carbon Eco-efficiency in Agro-ecosystem of Beijing, China

    Directory of Open Access Journals (Sweden)

    TIAN Zhi-hui

    2015-12-01

    Full Text Available Suburban farmland ecosystems are known to be affected by intensive land use/cover change (LUCC during the process of urbanization in Beijing. We investigated inter-annual changes in carbon sequestration, source, footprint, and eco-efficiency from 2004 to 2012 in the agro-ecosystem of suburban Beijing. Our findings indicated that: (1 Carbon sink increased 2.8 percent annually and the average annual carbon storage amount was 1 058 200 t, with food crops constituting the highest proportion at 80.4% of carbon storage in farmland ecosystems, of which maize contributed 68.5% as the largest constituent; (2 Carbon emission in the system showed a gradually decreasing trend, with agricultural chemicals as significant contributors. The annual average carbon emission was 276 000 tons in the Beijing farmland ecosystem, and decreased approximately 1.3 percent per year. The largest amount of carbon emissions came from agricultural chemicals at 85.4%, of which nitrogen fertilizer was the biggest contributor at 83.7%; ( 3 The carbon footprint also showed a decreasing trend along with an ecological surplus of carbon. The average carbon footprint was 5.71 hm2 in the Beijing farmland ecosystem with decreasing rate at 5.5% annually; however, the carbon surplus showed a downward trend due to reduction in the amount of arable land; (4 Finally, the increasing carbon sink capacity led to higher carbon eco-efficiency, with an annual average of 3.854 kg C·kg-1 CE, carbon sequestration was greater than the amount of carbon released. In summary, the agro-ecosystem in suburban Beijing has sustained a relatively high carbon eco-efficiency, and agricultural production continues to have high sustainability potential.

  14. Influence of different carbon monolith preparation parameters on pesticide adsorption

    Directory of Open Access Journals (Sweden)

    Vukčević Marija

    2013-01-01

    Full Text Available The capacity of carbon monolith for pesticide removal from water, and the mechanism of pesticide interaction with carbon surface were examined. Different carbon monolith samples were obtained by varying the carbonization and activation parameters. In order to examine the role of surface oxygen groups in pesticide adsorption, carbon monolith surface was functionalized by chemical treatment in HNO3, H2O2 and KOH. The surface properties of the obtained samples were investigated by BET surface area, pore size distribution and temperature-programmed desorption. Adsorption of pesticides from aqueous solution onto activated carbon monolith samples was studied by using five pesticides belonging to different chemical groups (acetamiprid, dimethoate, nicosulfuron, carbofuran and atrazine. Presented results show that higher temperature of carbonization and the amount of activating agent allow obtaining microporous carbon monolith with higher amount of surface functional groups. Adsorption properties of the activated carbon monolith were more readily affected by the amount of the surface functional groups than by specific surface area. Results obtained by carbon monolith functionalisation showed that π-π interactions were the main force for adsorption of pesticides with aromatic structure, while acidic groups play an important role in adsorption of pesticides with no aromatic ring in the chemical structure.

  15. Carbon dioxide sensor

    Science.gov (United States)

    Dutta, Prabir K [Worthington, OH; Lee, Inhee [Columbus, OH; Akbar, Sheikh A [Hilliard, OH

    2011-11-15

    The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).

  16. The effect of drought stress on carbon assimilation and isoprene emission capacities of oak species in urban and rural areas of Texas

    Science.gov (United States)

    Barta, C.; Gramann, J. H.; White, S. L.; Schade, G. W.

    2011-12-01

    Isoprene released from vegetation affects regional and global air quality directly through chemical reactions generating ozone and secondary organic aerosol, and indirectly through as a sink for the OH radical, leading to increased methane lifetimes. The formation and emission of biogenic isoprene is controlled by the emitting species' physical growth environment, and altered by exposure to environmental stress. It has been hypothesized that a warmer and more drought-prone climate as a consequence of global warming may enhance biogenic isoprene emissions with mostly positive feedbacks to warming. However, the magnitudes of these actions and reactions in a warming climate are uncertain, as their drivers are not yet completely understood. To address these interactions, we initiated a field study in spring 2011 to characterize the sensitivity of carbon assimilation and isoprene emission capacity of dominant Texas oak species (Quercus falcata, Q. nigra and Q.stellata) to measured climatic and pollution gradients along an urban to rural transect from downtown Houston to Sam Houston National Forest. We hypothesize that the conditions in urban areas may serve as a proxy for future warmer, more polluted and drier conditions. Leaf level measurements were conducted on sun-exposed leaves under standard conditions (30 C and 1000 PAR units); temperature and CO2 response curves, and post-illumination isoprene emissions were evaluated. Our results show, that the early onset of exceptional drought (SPI of -2 to -3, leading to soil moistures of less than 10%) had a strong impact on the assimilation of all studied species, with site-specific differences in species' response. Q. falcata and Q. nigra were particularly sensitive to their local environment. Their net assimilation abruptly declined by 90% below their expected optimum rates already in May and remained low throughout the summer at the urban and suburban sites. In contrast, Q. stellata, a species native to Texas, was more

  17. Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Ratcliffe, James G.; Luong, Hoa; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strengthand stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Despite several attempts to solve these issues with the addition of carbon nanotubes (CNT) into polymer matrices, and/or by interleaving CNT sheets between conventional carbon fiber (CF) composite layers, there are still interfacial problems that exist between CNTs (or CF) and the resin. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing (double cantilever beam and end-notched flexure test). Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated. Interleaving CNT sheets significantly improved the in-plane (axial and perpendicular direction of CF alignment) thermal conductivity of the hybrid composite laminates by 50 - 400%.

  18. Thermal Properties of Hybrid Carbon Nanotube/Carbon Fiber Polymer

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Luong, Hoa; Ratcliffe, James G.; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    Carbon fiber reinforced polymer (CFRP) composites possess many advantages for aircraft structures over conventional aluminum alloys: light weight, higher strength- and stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low thermal and electrical conductivities of CFRP composites are deficient in providing structural safety under certain operational conditions such as lightning strikes. One possible solution to these issues is to interleave carbon nanotube (CNT) sheets between conventional carbon fiber (CF) composite layers. However, the thermal and electrical properties of the orthotropic hybrid CNT/CF composites have not been fully understood. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel (Registered Trademark) IM7/8852 prepreg. The CNT sheets were infused with a 5% solution of a compatible epoxy resin prior to composite fabrication. Orthotropic thermal and electrical conductivities of the hybrid polymer composites were evaluated. The interleaved CNT sheets improved the in-plane thermal conductivity of the hybrid composite laminates by about 400% and the electrical conductivity by about 3 orders of magnitude.

  19. CO2 Capture by Carbon Aerogel–Potassium Carbonate Nanocomposites

    Directory of Open Access Journals (Sweden)

    Guang Yang

    2016-01-01

    Full Text Available Recently, various composites for reducing CO2 emissions have been extensively studied. Because of their high sorption capacity and low cost, alkali metal carbonates are recognized as a potential candidate to capture CO2 from flue gas under moist conditions. However, undesirable effects and characteristics such as high regeneration temperatures or the formation of byproducts lead to high energy costs associated with the desorption process and impede the application of these materials. In this study, we focused on the regeneration temperature of carbon aerogel–potassium carbonate (CA–KC nanocomposites, where KC nanocrystals were formed in the mesopores of the CAs. We observed that the nanopore size of the original CA plays an important role in decreasing the regeneration temperature and in enhancing the CO2 capture capacity. In particular, 7CA–KC, which was prepared from a CA with 7 nm pores, exhibited excellent performance, reducing the desorption temperature to 380 K and exhibiting a high CO2 capture capacity of 13.0 mmol/g-K2CO3, which is higher than the theoretical value for K2CO3 under moist conditions.

  20. Energy efficiency interventions in UK higher education institutions

    Energy Technology Data Exchange (ETDEWEB)

    Altan, Hasim [School of Architecture, The University of Sheffield, Crookesmoor Building, Conduit Road, Sheffield S10 1FL (United Kingdom)

    2010-12-15

    This paper provides an insight into energy efficiency interventions studies, focusing on issues arising in UK higher education institutions (HEIs) in particular. Based on a review of the context for energy efficiency and carbon reduction programmes in the UK and the trends in higher education sector, existing external and internal policies and initiatives and their relevant issues are extensively discussed. To explore the efficacy of some internal intervention strategies, such as technical, non-technical and management interventions, a survey was conducted among UK higher education institutions between February and April 2008. Consultation responses show that there are a relatively high percentage of institutions (83%) that have embarked on both technical and non-technical initiatives, which is a demonstration to the joined-up approach in such area. Major barriers for intervention studies are also identified, including lack of methodology, non-clarity of energy demand and consumption issues, difficulty in establishing assessment boundaries, problems with regards to indices and their effectiveness and so on. Besides establishing clear targets for carbon reductions within the sector, it is concluded that it is important to develop systems for effectively measuring and evaluating the impact of different policies, regulations and schemes in the future as the first step to explore. (author)

  1. Impact of sinking carbon flux on accumulation of deep-ocean carbon in the Northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; DileepKumar, M.; Saino, T.

    the carbon removed from the surface to deep waters takes hundreds of years to re-enter the atmosphere. The highest dissolved inorganic carbon (DIC) is expected in the deep waters of the North Pacific due to longer age of waters. On contrary, the higher deep...

  2. Dielectric barrier discharge carbon atomic emission spectrometer: universal GC detector for volatile carbon-containing compounds.

    Science.gov (United States)

    Han, Bingjun; Jiang, Xiaoming; Hou, Xiandeng; Zheng, Chengbin

    2014-01-07

    It was found that carbon atomic emission can be excited in low temperature dielectric barrier discharge (DBD), and an atmospheric pressure, low power consumption, and compact microplasma carbon atomic emission spectrometer (AES) was constructed and used as a universal and sensitive gas chromatographic (GC) detector for detection of volatile carbon-containing compounds. A concentric DBD device was housed in a heating box to increase the plasma operation temperature to 300 °C to intensify carbon atomic emission at 193.0 nm. Carbon-containing compounds directly injected or eluted from GC can be decomposed, atomized, and excited in this heated DBD for carbon atomic emission. The performance of this new optical detector was first evaluated by determination of a series of volatile carbon-containing compounds including formaldehyde, ethyl acetate, methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol, and absolute limits of detection (LODs) were found at a range of 0.12-0.28 ng under the optimized conditions. Preliminary experimental results showed that it provided slightly higher LODs than those obtained by GC with a flame ionization detector (FID). Furthermore, it is a new universal GC detector for volatile carbon-containing compounds that even includes those compounds which are difficult to detect by FID, such as HCHO, CO, and CO2. Meanwhile, hydrogen gas used in conventional techniques was eliminated; and molecular optical emission detection can also be performed with this GC detector for multichannel analysis to improve resolution of overlapped chromatographic peaks of complex mixtures.

  3. IUPAC-NIST Solubility Data Series. 97. Solubility of Higher Acetylenes and Triple Bonded Derivatives

    Science.gov (United States)

    Skrzecz, Adam

    2013-03-01

    Solubility of Ethyne in Liquids was published in 2001 as Vol. 76 of the IUPAC-NIST Solubility Data Series. The current work extends the coverage to the solubility in liquids of higher gaseous and liquid acetylenes and to derivatives that contain a triple carbon-carbon bond. Predictive methods for estimating solubilities in water are summarised and usually give values to within an order of magnitude. The literature has been surveyed to the end of 2010.

  4. Conductivity of single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Gets, A. V.; Krainov, V. P., E-mail: vpkrainov@mail.ru [Moscow Institute of Physics and Technology (Russian Federation)

    2016-12-15

    The conductivity of single-walled carbon nanotubes at low temperatures is calculated. It is shown that it is much higher than the well-known conductivity of a model 1D Fermi system. This is a purely quantum-mechanical effect.

  5. Large carbon release legacy from bark beetle outbreaks across Western United States.

    Science.gov (United States)

    Ghimire, Bardan; Williams, Christopher A; Collatz, G James; Vanderhoof, Melanie; Rogan, John; Kulakowski, Dominik; Masek, Jeffrey G

    2015-08-01

    Warmer conditions over the past two decades have contributed to rapid expansion of bark beetle outbreaks killing millions of trees over a large fraction of western United States (US) forests. These outbreaks reduce plant productivity by killing trees and transfer carbon from live to dead pools where carbon is slowly emitted to the atmosphere via heterotrophic respiration which subsequently feeds back to climate change. Recent studies have begun to examine the local impacts of bark beetle outbreaks in individual stands, but the full regional carbon consequences remain undocumented for the western US. In this study, we quantify the regional carbon impacts of the bark beetle outbreaks taking place in western US forests. The work relies on a combination of postdisturbance forest regrowth trajectories derived from forest inventory data and a process-based carbon cycle model tracking decomposition, as well as aerial detection survey (ADS) data documenting the regional extent and severity of recent outbreaks. We find that biomass killed by bark beetle attacks across beetle-affected areas in western US forests from 2000 to 2009 ranges from 5 to 15 Tg C yr(-1) and caused a reduction of net ecosystem productivity (NEP) of about 6.1-9.3 Tg C y(-1) by 2009. Uncertainties result largely from a lack of detailed surveys of the extent and severity of outbreaks, calling out a need for improved characterization across western US forests. The carbon flux legacy of 2000-2009 outbreaks will continue decades into the future (e.g., 2040-2060) as committed emissions from heterotrophic respiration of beetle-killed biomass are balanced by forest regrowth and accumulation. © 2015 John Wiley & Sons Ltd.

  6. Multiscale assessment of water limitations on forest carbon cycling in the western United States

    Science.gov (United States)

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

    2016-12-01

    Water is a key environmental constraint on carbon uptake, storage, and release by forests in the western United States. Climate in this region is becoming warmer and drier, thus highlighting the need to better understand how forest carbon cycling responds to variation in water availability. Here, we describe how forest carbon cycling varied spatially along local to regional gradients in climatic water availability. We examined local variation in net primary productivity (NPP) and aboveground biomass (AGB) using 12 intensive field plots in Oregon's Cascade Mountains. Regional analysis of forest NPP and AGB was based on federal forest inventories (>8,000 plots) in Washington, Oregon, and California, multiple biomass maps and MODIS NPP (2003-2012). We also quantified annual forest AGB mortality due to bark beetles and fires across the region from 2003-2012 by combining several disturbance and biomass data sets. Over each spatial extent, forest NPP and AGB increased curvilinearly with average growing-year climate moisture index, computed as the cumulative difference between precipitation and potential evapotranspiration from October-September and averaged over preceding decades. Thus, climatic water availability strongly constrains forest carbon uptake and storage, particularly in the driest areas, but also in the wettest. Forest AGB mortality rates from bark beetles and fires peaked in moderately dry forests and then declining rapidly in the wettest areas. Annual forest AGB mortality from bark beetles was about twice as high as from fires. Bark beetle impacts were most pronounced in the Rock Mountains, while fire impacts were most pronounced in western portion of the region. Our multiscale analysis based on field inventory and remote sensing data sets demonstrates that climatic water availability is a key environmental constraint on forest carbon cycling in the western US. Consequently, continued warming and drying can be expected to have substantial impacts on forest

  7. The Role of Anode Manufacturing Processes in Net Carbon Consumption

    Directory of Open Access Journals (Sweden)

    Khalil Khaji

    2016-05-01

    Full Text Available Carbon anodes are consumed in electrolysis cells during aluminum production. Carbon consumption in pre-bake anode cells is 400–450 kg C/t Al, considerably higher than the theoretical consumption of 334 kg C/t Al. This excess carbon consumption is partly due to the anode manufacturing processes. Net carbon consumption over the last three years at Emirates Aluminium (EMAL, also known as Emirates Global Aluminium (EGA Al Taweelah was analyzed with respect to anode manufacturing processes/parameters. The analysis indicates a relationship between net carbon consumption and many manufacturing processes, including anode desulfurization during anode baking. Anode desulfurization appears to increase the reaction surface area, thereby helping the Boudouard reaction between carbon and carbon dioxide in the electrolysis zone, as well as reducing the presence of sulfur which could inhibit this reaction. This paper presents correlations noted between anode manufacturing parameters and baked anode properties, and their impact on the net carbon consumption in electrolytic pots. Anode reactivities affect the carbon consumption in the pots during the electrolysis of alumina. Pitch content in anodes, impurities in anodes, and anode desulfurization during baking were studied to find their influence on anode reactivities. The understanding gained through this analysis helped reduce net carbon consumption by adjusting manufacturing processes. For an aluminum smelter producing one million tonnes of aluminum per year, the annual savings could be as much as US $0.45 million for every kg reduction in net carbon consumption.

  8. Thermal considerations in the cryogenic regime for the BNL double ridge higher order mode waveguide

    Directory of Open Access Journals (Sweden)

    Dhananjay K. Ravikumar

    2017-09-01

    Full Text Available Brookhaven National Laboratory (BNL has proposed to build an electron ion collider (EIC as an upgrade to the existing Relativistic Heavy Ion Collider (RHIC. A part of the new design is to use superconducting radio frequency (SRF cavities for acceleration, which sit in a bath of superfluid helium at a temperature of 2 K. SRF cavities designed for the BNL EIC create a standing electromagnetic wave, oscillating at a fundamental frequency of 647 MHz. Interaction of the charged particle beam with the EM field in the cavity creates higher order modes (HOM of oscillation which have adverse effects on the beam when allowed to propagate down the beam tube. HOM waveguides are thus designed to remove this excess energy which is then damped at room temperature. As a result, these waveguides provide a direct thermal link between room temperature and the superconducting cavities adding a static thermal load. The EM wave propagating through the warmer sections of the waveguide creates an additional dynamic thermal load. This study calculates these thermal loads, concluding that the dynamic load is small in comparison to the static load. Temperature distributions are mapped on the waveguide and the number of heat intercepts required to efficiently manage thermal loads have been determined. In addition, a thermal radiation study has been performed and it is found that this contribution is around three orders of magnitude smaller than the static conduction and dynamic loads.

  9. Thermal considerations in the cryogenic regime for the BNL double ridge higher order mode waveguide

    Science.gov (United States)

    Ravikumar, Dhananjay K.; Than, Yatming; Xu, Wencan; Longtin, Jon

    2017-09-01

    Brookhaven National Laboratory (BNL) has proposed to build an electron ion collider (EIC) as an upgrade to the existing Relativistic Heavy Ion Collider (RHIC). A part of the new design is to use superconducting radio frequency (SRF) cavities for acceleration, which sit in a bath of superfluid helium at a temperature of 2 K. SRF cavities designed for the BNL EIC create a standing electromagnetic wave, oscillating at a fundamental frequency of 647 MHz. Interaction of the charged particle beam with the EM field in the cavity creates higher order modes (HOM) of oscillation which have adverse effects on the beam when allowed to propagate down the beam tube. HOM waveguides are thus designed to remove this excess energy which is then damped at room temperature. As a result, these waveguides provide a direct thermal link between room temperature and the superconducting cavities adding a static thermal load. The EM wave propagating through the warmer sections of the waveguide creates an additional dynamic thermal load. This study calculates these thermal loads, concluding that the dynamic load is small in comparison to the static load. Temperature distributions are mapped on the waveguide and the number of heat intercepts required to efficiently manage thermal loads have been determined. In addition, a thermal radiation study has been performed and it is found that this contribution is around three orders of magnitude smaller than the static conduction and dynamic loads.

  10. Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem

    Directory of Open Access Journals (Sweden)

    J. A. O'Donnell

    2011-05-01

    Full Text Available In the boreal region, soil organic carbon (OC dynamics are strongly governed by the interaction between wildfire and permafrost. Using a combination of field measurements, numerical modeling of soil thermal dynamics, and mass-balance modeling of OC dynamics, we tested the sensitivity of soil OC storage to a suite of individual climate factors (air temperature, soil moisture, and snow depth and fire severity. We also conducted sensitivity analyses to explore the combined effects of fire-soil moisture interactions and snow seasonality on OC storage. OC losses were calculated as the difference in OC stocks after three fire cycles (~500 yr following a prescribed step-change in climate and/or fire. Across single-factor scenarios, our findings indicate that warmer air temperatures resulted in the largest relative soil OC losses (~5.3 kg C m−2, whereas dry soil conditions alone (in the absence of wildfire resulted in the smallest carbon losses (~0.1 kg C m−2. Increased fire severity resulted in carbon loss of ~3.3 kg C m−2, whereas changes in snow depth resulted in smaller OC losses (2.1–2.2 kg C m−2. Across multiple climate factors, we observed larger OC losses than for single-factor scenarios. For instance, high fire severity regime associated with warmer and drier conditions resulted in OC losses of ~6.1 kg C m−2, whereas a low fire severity regime associated with warmer and wetter conditions resulted in OC losses of ~5.6 kg C m−2. A longer snow-free season associated with future warming resulted in OC losses of ~5.4 kg C m−2. Soil climate was the dominant control on soil OC loss, governing the sensitivity of microbial decomposers to fluctuations in temperature and soil moisture; this control, in turn, is governed by interannual changes in active layer depth. Transitional responses of the active layer depth to fire regimes also contributed to OC losses

  11. Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem

    Science.gov (United States)

    O'Donnell, J. A.; Harden, J.W.; McGuire, A.D.; Romanovsky, V.E.

    2011-01-01

    In the boreal region, soil organic carbon (OC) dynamics are strongly governed by the interaction between wildfire and permafrost. Using a combination of field measurements, numerical modeling of soil thermal dynamics, and mass-balance modeling of OC dynamics, we tested the sensitivity of soil OC storage to a suite of individual climate factors (air temperature, soil moisture, and snow depth) and fire severity. We also conducted sensitivity analyses to explore the combined effects of fire-soil moisture interactions and snow seasonality on OC storage. OC losses were calculated as the difference in OC stocks after three fire cycles (???500 yr) following a prescribed step-change in climate and/or fire. Across single-factor scenarios, our findings indicate that warmer air temperatures resulted in the largest relative soil OC losses (???5.3 kg C mg-2), whereas dry soil conditions alone (in the absence of wildfire) resulted in the smallest carbon losses (???0.1 kg C mg-2). Increased fire severity resulted in carbon loss of ???3.3 kg C mg-2, whereas changes in snow depth resulted in smaller OC losses (2.1-2.2 kg C mg-2). Across multiple climate factors, we observed larger OC losses than for single-factor scenarios. For instance, high fire severity regime associated with warmer and drier conditions resulted in OC losses of ???6.1 kg C mg-2, whereas a low fire severity regime associated with warmer and wetter conditions resulted in OC losses of ???5.6 kg C mg-2. A longer snow-free season associated with future warming resulted in OC losses of ???5.4 kg C mg-2. Soil climate was the dominant control on soil OC loss, governing the sensitivity of microbial decomposers to fluctuations in temperature and soil moisture; this control, in turn, is governed by interannual changes in active layer depth. Transitional responses of the active layer depth to fire regimes also contributed to OC losses, primarily by determining the proportion of OC into frozen and unfrozen soil layers

  12. Carbon monoxide poisoning

    OpenAIRE

    Dolan, Michael C.

    1985-01-01

    Carbon monoxide poisoning is a significant cause of illness and death. Its protean symptoms probably lead to a gross underestimation of its true incidence. Low levels of carbon monoxide aggravate chronic cardiopulmonary problems, and high levels are associated with cardiac arrhythmias and cerebral edema. Patients who survive acute poisoning are at risk of delayed neurologic sequelae. The measurement of carboxyhemoglobin levels does not reveal the tissue levels of carbon monoxide but is useful...

  13. Carbon nanotubes decorating methods

    OpenAIRE

    A.D. Dobrzańska-Danikiewicz; Łukowiec, D.; D. Cichock; W. Wolany

    2013-01-01

    Purpose: The work is to present and characterise various methods of depositing carbon nanotubes with nanoparticles of precious metals, and also to present the results of own works concerning carbon nanotubes coated with platinum nanoparticles.Design/methodology/approach: Electron transmission and scanning microscopy has been used for imaging the structure and morphology of the nanocomposites obtained and the distribution of nanoparticles on the surface of carbon nanotubes.Findings: The studie...

  14. Carbon monoxide poisoning (acute)

    OpenAIRE

    Olson, Kent; Smollin, Craig

    2008-01-01

    The main symptoms of carbon monoxide poisoning are non-specific in nature and relate to effects on the brain and heart. The symptoms correlate poorly with serum carboxyhaemoglobin levels. People with comorbidity, the elderly or very young, and pregnant women are most susceptible.Carbon monoxide is produced by the incomplete combustion of carbon fuels, including inadequately ventilated heaters and car exhausts, or from chemicals such as methylene chloride paint stripper.Poisoning is conside...

  15. Carbon monoxide poisoning (acute)

    OpenAIRE

    Smollin, Craig; Olson, Kent

    2010-01-01

    The main symptoms of carbon monoxide poisoning are non-specific in nature and relate to effects on the brain and heart. The symptoms correlate poorly with serum carboxyhaemoglobin levels. People with comorbidity, elderly or very young people, and pregnant women are most susceptible.Carbon monoxide is produced by the incomplete combustion of carbon fuels, including inadequately ventilated heaters and car exhausts, or from chemicals such as methylene chloride paint stripper.Poisoning is cons...

  16. Carbon emissions in China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhu [Harvard Univ., Cambridge, MA (United States). Sustainability Science Program

    2016-07-01

    This study analyzes the spatial-temporal pattern and processes of China's energy-related carbon emissions. Based on extensive quantitative analysis, it outlines the character and trajectory of China's energy-related carbon emissions during the period 1995-2010, examining the distribution pattern of China's carbon emissions from regional and sectoral perspectives and revealing the driving factors of China's soaring emission increase. Further, the book investigates the supply chain carbon emissions (the carbon footprints) of China's industrial sectors. Anthropogenic climate change is one of the most serious challenges currently facing humankind. China is the world's largest developing country, top primary energy consumer and carbon emitter. Achieving both economic growth and environmental conservation is the country's twofold challenge. Understanding the status, features and driving forces of China's energy-related carbon emissions is a critical aspect of attaining global sustainability. This work, for the first time, presents both key findings on and a systematic evaluation of China's carbon emissions from energy consumption. The results have important implications for global carbon budgets and burden-sharing with regard to climate change mitigation. The book will be of great interest to readers around the world, as it addresses a topic of truly global significance.

  17. Carbon Trading. Literature Overview

    Energy Technology Data Exchange (ETDEWEB)

    Kerste, M.; Weda, J.; Rosenboom, N.

    2010-12-15

    From Pigou and Coase to the Kyoto Protocol, carbon trading has resulted in pricing of the negative externalities emanating from pollution. This report highlights leading literature and empirical findings on carbon trading, amongst others addressing the relevant carbon and related markets, the (lack of) success of carbon trading so far and room for improvement as well as its impact on investments in emission reduction. This report is part of a set of SEO-reports on finance and sustainability. The other reports deal with: Financing the Transition to Sustainable Energy; Innovations in financing environmental and social sustainability; and Sustainable investment.

  18. The decadal state of the terrestrial carbon cycle: Global retrievals of terrestrial carbon allocation, pools, and residence times.

    Science.gov (United States)

    Bloom, A Anthony; Exbrayat, Jean-François; van der Velde, Ivar R; Feng, Liang; Williams, Mathew

    2016-02-02

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle and its processes is, therefore, necessary to better understand its current state and predict its future state. We combine a diagnostic ecosystem carbon model with satellite observations of leaf area and biomass (where and when available) and soil carbon data to retrieve the first global estimates, to our knowledge, of carbon cycle state and process variables at a 1° × 1° resolution; retrieved variables are independent from the plant functional type and steady-state paradigms. Our results reveal global emergent relationships in the spatial distribution of key carbon cycle states and processes. Live biomass and dead organic carbon residence times exhibit contrasting spatial features (r = 0.3). Allocation to structural carbon is highest in the wet tropics (85-88%) in contrast to higher latitudes (73-82%), where allocation shifts toward photosynthetic carbon. Carbon use efficiency is lowest (0.42-0.44) in the wet tropics. We find an emergent global correlation between retrievals of leaf mass per leaf area and leaf lifespan (r = 0.64-0.80) that matches independent trait studies. We show that conventional land cover types cannot adequately describe the spatial variability of key carbon states and processes (multiple correlation median = 0.41). This mismatch has strong implications for the prediction of terrestrial carbon dynamics, which are currently based on globally applied parameters linked to land cover or plant functional types.

  19. Predicting new phases of carbon, carbonates, and carbides

    Science.gov (United States)

    Oganov, A. R.; Zhu, Q.; Lyakhov, A. O.; Zeng, Q.

    2012-12-01

    We will discuss latest developments and applications of the USPEX code [1] to carbon-based materials: -We predicted structures of two high-pressure phases of CaCO3 [2] and two complex new high-pressure structures of MgCO3 [3], and our predictions have just been confirmed by experiment. We find that in the top part of the Earth's mantle diamond and MgCO3 magnesite will be the main host of C, but most of the lower mantle will contain carbon in the form of Fe3C cementite, diamond and MgCO3 phases (magnesite and post-magnesite phase). In the D" layer, CaCO3 with a pyroxene-like structure will be stable. -For the Fe-C system at pressures of the Earth's inner core, contrary to conventional wisdom, Fe3C and Fe7C3 are not thermodynamically stable compounds at relevant pressures - the only stable iron carbide is the orthorhombic (Pnma) phase of Fe2C [4]. The upper bound for the carbon content in the inner core is 11-15 mol.% (2.6-3.7 wt.%), and we conclude that carbon is a likely important light alloying element in the core. -We studied possible decomposition of methane. We confirm [5] that methane on compression initially polymerizes into ethane and butane, and it still higher pressures diamond is formed. Thus, it is confirmed that heat can be is produced in Neptune's interior by sinking large amounts of diamond. -Now it is possible to perform optimization of physical properties, e,g, the density and hardness [6,7], which allowed the predicted the densest possible structures of carbon [6]. These are up to 3.2% denser than diamond and possess interesting optical and electronic properties and their strong similarities with known phases of silica, quartz and keatite. It was also proven [7] that diamond is the hardest possible allotrope of carbon. -The evolutionary metadynamics technique [8] allowed us to predict the full set of candidate structures that could be formed upon low-temperature compression of graphite [9]. This includes our earlier proposed [1,10] monoclinic (M-carbon

  20. Peculiarities of the initial stages of carbonization processes in polyimide-based nanocomposite films containing carbon nanoparticles

    Directory of Open Access Journals (Sweden)

    I.V. Gofman

    2015-12-01

    Full Text Available Carbonization of the polyimide-based composite films containing carbon nanoparticles, namely nanofibers and nanocones/disks, in the temperature range 500–550°C was studied and the kinetics of the initial stage of carbonization and the effect of the filler on the mechanical properties of the carbonized films were evaluated. Two polyimides (PIs characterized by different macrochains’ rigidity and different degrees of ordering of the intermolecular structure were used. The character of the nanofiller’s action on the kinetics of the carbonization process depends on the heating rate. In this work, the intensity of the destruction of the PI matrix of the composite films was shown to be slightly higher than that of films of the same polymers with no filler. The introduction of the carbon nanoparticles into both PIs provokes the increase in the ultimate deformation values of the partially carbonized films, while the carbonization of the unfilled PI films yields the brittle materials. The Young’s modulus values of the materials based on the rigid-rod PI do not increase after carbonization, while those for compositions based on the PI with semi-rigid chains increase substantially. Carbon nanocones/disks are characterized by the best compatibility with matrix PIs in comparison with carbon nanofibers.

  1. Enhanced decomposition offsets enhanced productivity and soil carbon accumulation in coastal wetlands responding to climate change

    Directory of Open Access Journals (Sweden)

    M. L. Kirwan

    2011-04-01

    Full Text Available Coastal wetlands are responsible for about half of all carbon burial in oceans, and their persistence as a valuable ecosystem depends largely on the ability to accumulate organic material at rates equivalent to relative sea level rise. Recent work suggests that elevated CO2 and temperature warming will increase organic matter productivity and the ability of marshes to survive sea level rise. However, we find in a series of preliminary experiments that organic decomposition rates increase by about 20% per degree of warming. Our measured temperature sensitivity is similar to studies from terrestrial systems, three times as high as the response of salt marsh productivity to temperature warming, and greater than the productivity response associated with elevated CO2 in C3 marsh plants. Although the experiments were simple and of short duration, they suggest that enhanced CO2 and warmer temperatures could actually make marshes less resilient to sea level rise, and tend to promote a release of soil carbon. Simple projections indicate that elevated temperatures will increase rates of sea level rise more than any acceleration in organic matter accumulation, suggesting the possibility of a positive feedback between climate, sea level rise, and carbon emissions in coastal environments.

  2. Long-term warming amplifies shifts in the carbon cycle of experimental ponds

    Science.gov (United States)

    Yvon-Durocher, Gabriel; Hulatt, Chris J.; Woodward, Guy; Trimmer, Mark

    2017-02-01

    Lakes and ponds cover only about 4% of the Earth’s non-glaciated surface, yet they represent disproportionately large sources of methane and carbon dioxide. Indeed, very small ponds (for example, <0.001 km2) may account for approximately 40% of all CH4 emissions from inland waters. Understanding how greenhouse gas emissions from aquatic ecosystems will respond to global warming is therefore vital for forecasting biosphere-carbon cycle feedbacks. Here, we present findings on the long-term effects of warming on the fluxes of GHGs and rates of ecosystem metabolism in experimental ponds. We show that shifts in CH4 and CO2 fluxes, and rates of gross primary production and ecosystem respiration, observed in the first year became amplified over seven years of warming. The capacity to absorb CO2 was nearly halved after seven years of warmer conditions. The phenology of greenhouse gas fluxes was also altered, with CO2 drawdown and CH4 emissions peaking one month earlier in the warmed treatments. These findings show that warming can fundamentally alter the carbon balance of small ponds over a number of years, reducing their capacity to sequester CO2 and increasing emissions of CH4; such positive feedbacks could ultimately accelerate climate change.

  3. Heterotrophic Soil Respiration in Warming Experiments: Using Microbial Indicators to Partition Contributions from Labile and Recalcitrant Soil Organic Carbon. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Bradford, M A; Melillo, J M; Reynolds, J F; Treseder, K K; Wallenstein, M D

    2010-06-10

    microbial community. There are distinct seasonal patterns and to long-term soil warming, with higher-temperature optima for soils exposed to warmer temperatures. To relate these changes within the microbial community to potential positive feedbacks between climate warming and soil respiration, we develop a microbial-enzyme model to simulate the responses of soil carbon to warming. We find that declines in microbial biomass and degradative enzymes can explain the observed attenuation of soil-carbon emissions in response to warming. Specifically, reduced carbon-use efficiency limits the biomass of microbial decomposers and mitigates loss of soil carbon. However, microbial adaptation or a change in microbial communities could lead to an upward adjustment of the efficiency of carbon use, counteracting the decline in microbial biomass and accelerating soil-carbon loss. We conclude that the soil-carbon response to climate warming depends on the efficiency of soil microbes in using carbon.

  4. Metabolic engineering of higher plants and algae for isoprenoid production.

    Science.gov (United States)

    Kempinski, Chase; Jiang, Zuodong; Bell, Stephen; Chappell, Joe

    2015-01-01

    Isoprenoids are a class of compounds derived from the five carbon precursors, dimethylallyl diphosphate, and isopentenyl diphosphate. These molecules present incredible natural chemical diversity, which can be valuable for humans in many aspects such as cosmetics, agriculture, and medicine. However, many terpenoids are only produced in small quantities by their natural hosts and can be difficult to generate synthetically. Therefore, much interest and effort has been directed toward capturing the genetic blueprint for their biochemistry and engineering it into alternative hosts such as plants and algae. These autotrophic organisms are attractive when compared to traditional microbial platforms because of their ability to utilize atmospheric CO2 as a carbon substrate instead of supplied carbon sources like glucose. This chapter will summarize important techniques and strategies for engineering the accumulation of isoprenoid metabolites into higher plants and algae by choosing the correct host, avoiding endogenous regulatory mechanisms, and optimizing potential flux into the target compound. Future endeavors will build on these efforts by fine-tuning product accumulation levels via the vast amount of available "-omic" data and devising metabolic engineering schemes that integrate this into a whole-organism approach. With the development of high-throughput transformation protocols and synthetic biology molecular tools, we have only begun to harness the power and utility of plant and algae metabolic engineering.

  5. Carbon nanofibers grown on activated carbon fiber fabrics as electrode of supercapacitors

    Science.gov (United States)

    Ko, Tse-Hao; Hung, Kai-Hsuan; Tzeng, Shinn-Shyong; Shen, Jin-Wei; Hung, Cheng-Hsin

    2007-12-01

    Carbon nanofibers (CNFs) were grown directly on activated carbon fiber fabric (ACFF), which was then used as the electrode of supercapacitors. Cyclic voltammetry and ac impedance were used to characterize the electrochemical properties of ACFF and CNF/ACFF electrodes in both aqueous and organic electrolytes. ACFF electrodes show higher specific capacitance than CNF/ACFF electrodes due to larger specific surface area. However, the spaces formed between the CNFs in the CNF/ACFF electrodes are more easily accessed than the slit-type pores of ACFF, and much higher electrical-double layer capacitance was obtained for CNF/ACFF electrodes.

  6. Role of activated carbon on micropollutans degradation by different radiation processes

    Directory of Open Access Journals (Sweden)

    Inmaculada Velo Gala

    2015-04-01

    Full Text Available The objective of this study was to analyse the influence of the presence of activated carbon on radiation processes. The triiodinated contrast medium diatrizoate was chosen as the contaminant model. We selected four commercial activated carbons and sixteen gamma radiation-modified carbons derived from these. The different advanced oxidation/reduction processes that have been studied were improved through the addition of activated carbon in the UV light and gamma radiating processes. In the UV/activated carbon process, the synergic activity of the activated carbon is enhanced in the samples with higher percentages of surface oxygen, ester/anhydride groups and carbon atoms with sp2 hybridization. Band gap determination of activated carbons revealed that they behave as semiconductor materials and, therefore, as photoactive materials in the presence of UV radiation, given that all band gap values are <4 eV. We also observed that the gamma radiation treatment reduces the band gap values of the activated carbons and that, in a single series of commercial carbons, lower band gap values correspond to higher contaminant removal rate values. We observed that the activity of the reutilized activated carbons is similar to that of the original carbons. Based on these results, we proposed that the activated carbon acts as a photocatalyst, promoting electrons of the valence band to the conduction band and increasing the generation of HO• radicals in the medium. Similarly, there was a synergic effect made by the presence of activated carbon in gamma radiation system, which favours pollutant removal. This synergic effect is independent of the textural but not the chemical characteristics of the activated carbon, observing a higher synergic activity for carbons with a higher surface content of oxygen, specifically quinone groups. We highlight that the synergic effect of the activated carbon requires adsorbent–adsorbate electrostatic interaction and is absent

  7. Organic carbon, nitrogen and phosphorus in the Great Astrolabe Reef lagoon sediments : preliminary results

    OpenAIRE

    Charpy Roubaud, Claude; Sarazin, G.; Buscail, R.

    1996-01-01

    Carbon, nitrogen and phosphorus were studied in the Great Astrolabe Reef sediment. Organic carbon, nitrogen and phosphorus percentages were respectively, in average for the whole lagoon top layer sediment, 0.19, 0.024 and 0.006. Organic carbon was lower than this measured in the French Polynesian atolls, organic phosphorus was higher. (Résumé d'auteur)

  8. Preparation of Fe-cored carbon nanomaterials from mountain pine beetle-killed pine wood

    Science.gov (United States)

    Sung Phil Mun; Zhiyong Cai; Jilei Zhang

    2015-01-01

    The mountain pine beetle-killed lodgepole pine (Pinus contorta) wood treated with iron (III) nitrate solution was used for the preparation of Fe-cored carbon nanomaterials (Fe-CNs) under various carbonization temperatures. The carbonization yield of Fe-treated sample (5% as Fe) was always 1–3% higher (after ash compensation) than that of the non-...

  9. The theoretical and empirical basis for understanding the impact of thinning on carbon stores in forests

    Science.gov (United States)

    Mark E. Harmon

    2013-01-01

    Th inning of forests has been proposed as a means to increase the carbon stores of forests. Th e justifi cation often offered is that thinning increases stand productivity, which in turn leads to higher carbon stores. While thinning of forests clearly increases the growth of residual trees and increases the amount of harvested carbon compared to an unthinned stand,...

  10. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    Science.gov (United States)

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

  11. Carbon footprint of grain production in China.

    Science.gov (United States)

    Zhang, Dan; Shen, Jianbo; Zhang, Fusuo; Li, Yu'e; Zhang, Weifeng

    2017-06-29

    Due to the increasing environmental impact of food production, carbon footprint as an indicator can guide farmland management. This study established a method and estimated the carbon footprint of grain production in China based on life cycle analysis (LCA). The results showed that grain production has a high carbon footprint in 2013, i.e., 4052 kg ce/ha or 0.48 kg ce/kg for maize, 5455 kg ce/ha or 0.75 kg ce/kg for wheat and 11881 kg ce/ha or 1.60 kg ce/kg for rice. These footprints are higher than that of other countries, such as the United States, Canada and India. The most important factors governing carbon emissions were the application of nitrogen fertiliser (8-49%), straw burning (0-70%), energy consumption by machinery (6-40%), energy consumption for irrigation (0-44%) and CH4 emissions from rice paddies (15-73%). The most important carbon sequestration factors included returning of crop straw (41-90%), chemical nitrogen fertiliser application (10-59%) and no-till farming practices (0-10%). Different factors dominated in different crop systems in different regions. To identity site-specific key factors and take countermeasures could significantly lower carbon footprint, e.g., ban straw burning in northeast and south China, stopping continuous flooding irrigation in wheat and rice production system.

  12. Making Activated Carbon for Storing Gas

    Science.gov (United States)

    Wojtowicz, Marek A.; Serio, Michael A.; Suuberg, Eric M.

    2005-01-01

    Solid disks of microporous activated carbon, produced by a method that enables optimization of pore structure, have been investigated as means of storing gas (especially hydrogen for use as a fuel) at relatively low pressure through adsorption on pore surfaces. For hydrogen and other gases of practical interest, a narrow distribution of pore sizes carbon is alternately (1) heated to the lower of two elevated temperatures in air or other oxidizing gas, causing the formation of stable carbon/oxygen surface complexes; then (2) heated to the higher of the two elevated temperatures in flowing helium or other inert gas, causing the desorption of the surface complexes in the form of carbon monoxide. In the present method, pore structure is optimized partly by heating to a temperature of 1,100 C during carbonization. Another aspect of the method exploits the finding that for each gas-storage pressure, gas-storage capacity can be maximized by burning off a specific proportion (typically between 10 and 20 weight percent) of the carbon during the cyclic chemisorption/desorption process.

  13. Low-temperature Condensation of Carbon

    Science.gov (United States)

    Krasnokutski, S. A.; Goulart, M.; Gordon, E. B.; Ritsch, A.; Jäger, C.; Rastogi, M.; Salvenmoser, W.; Henning, Th.; Scheier, P.

    2017-10-01

    Two different types of experiments were performed. In the first experiment, we studied the low-temperature condensation of vaporized graphite inside bulk liquid helium, while in the second experiment, we studied the condensation of single carbon atoms together with H2, H2O, and CO molecules inside helium nanodroplets. The condensation of vaporized graphite leads to the formation of partially graphitized carbon, which indicates high temperatures, supposedly higher than 1000°C, during condensation. Possible underlying processes responsible for the instant rise in temperature during condensation are discussed. This suggests that such processes cause the presence of partially graphitized carbon dust formed by low-temperature condensation in the diffuse interstellar medium. Alternatively, in the denser regions of the ISM, the condensation of carbon atoms together with the most abundant interstellar molecules (H2, H2O, and CO), leads to the formation of complex organic molecules (COMs) and finally organic polymers. Water molecules were found not to be involved directly in the reaction network leading to the formation of COMs. It was proposed that COMs are formed via the addition of carbon atoms to H2 and CO molecules ({{C}}+{{{H}}}2\\to {HCH},{HCH}+{CO}\\to {{OCCH}}2). Due to the involvement of molecular hydrogen, the formation of COMs by carbon addition reactions should be more efficient at high extinctions compared with the previously proposed reaction scheme with atomic hydrogen.

  14. Holocene carbon cycle dynamics: HOLOCENE CARBON CYCLE DYNAMICS

    National Research Council Canada - National Science Library

    Kleinen, Thomas; Brovkin, Victor; von Bloh, Werner; Archer, David; Munhoven, Guy

    2010-01-01

    .... Apart from the deep sea sediments, important carbon cycle processes considered are carbon uptake or release by the vegetation, carbon uptake by peatlands, and CO2 release due to shallow water sedimentation of CaCO3...

  15. DEVELOPMENT OF ACTIVATED CARBONS FROM COAL COMBUSTION BY-PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    Harold H. Schobert; M. Mercedes Maroto-Valer; Zhe Lu

    2003-09-30

    inferred from their physical and chemical properties. The developed porosity of the activated carbon was a function of the oxygen content, porosity and H/C ratio of the parent unburned carbon feedstock. It was observed that extended activation times and high activation temperatures increased the porosity of the produced activated carbon at the expense of the solid yield. The development of activated carbon from unburned carbon in fly ash has been proven to be a success by this study in terms of the higher surface areas of the resultant activated carbons, which are comparable with commercial activated carbons. However, unburned carbon samples obtained from coal-fired power plants as by-product have high ash content, which is unwanted for the production of activated carbons. Therefore, the separation of unburned carbon from the fly ash is expected to be beneficial for the utilization of unburned carbon to produce activated carbons with low ash content.

  16. Novel phase of carbon, ferromagnetism, and conversion into diamond

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Jagdish, E-mail: narayan@ncsu.edu; Bhaumik, Anagh [Department of Materials Science and Engineering, Centennial Campus, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States)

    2015-12-07

    We report the discovery of a new phase of carbon (referred to as Q-carbon) and address fundamental issues related to direct conversion of carbon into diamond at ambient temperatures and pressures in air without any need for catalyst and presence of hydrogen. The Q-carbon is formed as result of quenching from super undercooled state by using high-power nanosecond laser pulses. We discuss the equilibrium phase diagram (P vs. T) of carbon and show that by rapid quenching kinetics can shift thermodynamic graphite/diamond/liquid carbon triple point from 5000 K/12 GPa to super undercooled carbon at atmospheric pressure in air. It is shown that nanosecond laser heating of diamond-like amorphous carbon on sapphire, glass, and polymer substrates can be confined to melt carbon in a super undercooled state. By quenching the carbon from the super undercooled state, we have created a new state of carbon (Q-carbon) from which nanodiamond, microdiamond, microneedles, and single-crystal thin films are formed depending upon the nucleation and growth times allowed for diamond formation. The Q-carbon quenched from liquid is a new state of solid carbon with a higher mass density than amorphous carbon and a mixture of mostly fourfold sp{sup 3} (75%–85%) with the rest being threefold sp{sup 2} bonded carbon (with distinct entropy). It is expected to have new and improved mechanical hardness, electrical conductivity, chemical, and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission. Here we present interesting results on RTFM, enhanced electrical conductivity and surface potential of Q-carbon to emphasize its unique properties. The Q-carbon exhibits robust bulk ferromagnetism with estimated Curie temperature of about 500 K and saturation magnetization value of 20 emu g{sup −1}. From the Q-carbon, diamond phase is nucleated and a variety of micro- and nanostructures and large-area single-crystal diamond sheets are grown by allowing

  17. Mesoscale features create hotspots of carbon uptake in the Antarctic Circumpolar Current

    Science.gov (United States)

    Jones, Elizabeth M.; Hoppema, Mario; Strass, Volker; Hauck, Judith; Salt, Lesley; Ossebaar, Sharyn; Klaas, Christine; van Heuven, Steven M. A. C.; Wolf-Gladrow, Dieter; Stöven, Tim; de Baar, Hein J. W.

    2017-04-01

    The influence of eddy structures on the seasonal depletion of dissolved inorganic carbon (DIC) and carbon dioxide (CO2) disequilibrium was investigated during a trans-Atlantic crossing of the Antarctic Circumpolar Current (ACC) in austral summer 2012. The Georgia Basin, downstream of the island of South Georgia (54-55°S, 36-38°W) is a highly dynamic region due to the mesoscale activity associated with the flow of the Subantarctic Front (SAF) and Polar Front (PF). Satellite sea-surface height and chlorophyll-a anomalies revealed a cyclonic cold core that dominated the northern Georgia Basin that was formed from a large meander of the PF. Warmer waters influenced by the SAF formed a smaller anticyclonic structure to the east of the basin. Both the cold core and warm core eddy structures were hotspots of carbon uptake relative to the rest of the ACC section during austral summer. This was most amplified in the cold core where greatest CO2 undersaturation (-78 μatm) and substantial surface ocean DIC deficit (5.1 mol m-2) occurred. In the presence of high wind speeds, the cold core eddy acted as a strong sink for atmospheric CO2 of 25.5 mmol m-2 day-1. Waters of the warm core displayed characteristics of the Polar Frontal Zone (PFZ), with warmer upper ocean waters and enhanced CO2 undersaturation (-59 μatm) and depletion of DIC (4.9mol m-2). A proposed mechanism for the enhanced carbon uptake across both eddy structures is based on the Ekman eddy pumping theory: (i) the cold core is seeded with productive (high chlorophyll-a) waters from the Antarctic Zone and sustained biological productivity through upwelled nutrient supply that counteracts DIC inputs from deep waters; (ii) horizontal entrainment of low-DIC surface waters (biological uptake) from the PFZ downwell within the warm core and cause relative DIC-depletion in the upper water column. The observations suggest that the formation and northward propagation of cold core eddies in the region of the PF could

  18. The carbon holdings of northern Ecuador's mangrove forests

    CERN Document Server

    Hamilton, Stuart E; Borbor, Mercy; Millones, Marco

    2016-01-01

    Within a GIS environment, we combine field measures of mangrove diameter, mangrove species distribution, and mangrove density with remotely sensed measures of mangrove location and mangrove canopy cover to estimate the mangrove carbon holdings of northern Ecuador. We find that the four northern estuaries of Ecuador contain approximately 7,742,999 t (plus or minus 15.47 percent) of standing carbon. Of particular high carbon holdings are the Rhizophora mangle dominated mangrove stands found in-and-around the Cayapas-Mataje Ecological Reserve in northern Esmeraldas Province, Ecuador and certain stands of Rhizophora mangle in-and-around the Isla Corazon y Fragata Wildlife Refuge in central Manabi Province, Ecuador. Our field driven mangrove carbon estimate is higher than all but one of the comparison models evaluated. We find that basic latitudinal mangrove carbon models performed at least as well, if not better, than the more complex species based allometric models in predicting standing carbon levels. In additi...

  19. Renewable energy and low carbon economy transition in India

    DEFF Research Database (Denmark)

    Shukla, P.R.; Dhar, Subash; Fujino, Junichi

    2010-01-01

    will be higher under a sustainable pathway. Renewable energy faces competition from low carbon technologies like nuclear and carbon capture and storage in the electricity sector. Solar, wind, biomass, and biofuels emerge as the four competitive renewable energy choices for India. Renewable development however......Cooperation of large developing countries such as India would be important in achieving a low carbon future, which can help in restricting the global temperature rise to 2 °C. Global modeling studies of such low carbon scenarios point to a prominent role for renewable energy. This paper reports...... scenarios for a low carbon future in India. An integrated modeling framework is used for assessing the alternate development pathways having equal cumulative CO2 emissions. The modeling period ranges from 2005 to 2050. The first pathway assumes a conventional development pattern together with a carbon price...

  20. Warm-adapted microbial communities enhance their carbon-use efficiency in warmed soils

    Science.gov (United States)

    Rousk, Johannes; Frey, Serita

    2017-04-01

    Ecosystem models predict that climate warming will stimulate microbial decomposition of soil carbon (C), resulting in a positive feedback to increasing temperatures. The current generation of models assume that the temperature sensitivities of microbial processes do not respond to warming. However, recent studies have suggested that the ability of microbial communities to adapt to warming can lead both strengthened and weakened feedbacks. A further complication is that the balance between microbial C used for growth to that used for respiration - the microbial carbon-use efficiency (CUE) - also has been shown through both modelling and empirical study to respond to warming. In our study, we set out to assess how chronic warming (+5°C over ambient during 9 years) of a temperate hardwood forest floor (Harvard Forest LTER, USA) affected temperature sensitivities of microbial processes in soil. To do this, we first determined the temperature relationships for bacterial growth, fungal growth, and respiration in plots exposed to warmed or ambient conditions. Secondly, we parametrised the established temperature functions microbial growth and respiration with plot-specific measured soil temperature data at a hourly time-resolution over the course of 3 years to estimate the real-time variation of in situ microbial C production and respiration. To estimate the microbial CUE, we also divided the microbial C production with the sum of microbial C production and respiration as a proxy for substrate use. We found that warm-adapted bacterial and fungal communities both shifted their temperature relationships to grow at higher rates in warm conditions which coincided with reduced rates at cool conditions. As such, their optimal temperature (Topt), minimum temperature (Tmin) and temperature sensitivity (Q10) were all increased. The temperature relationship for temperature, in contrast, was only marginally shifted in the same direction, but at a much smaller effect size, with