WorldWideScience

Sample records for belowground processes limitations

  1. Above- and belowground competition from longleaf pine plantations limits performance of reintroduced herbaceous species.

    Energy Technology Data Exchange (ETDEWEB)

    T.B. Harrington; C.M. Dagley; M.B. Edwards.

    2003-10-01

    Although overstory trees limit the abundance and species richness of herbaceous vegetation in longleaf pine (Pinus palustris Mill.) plantations, the responsible mechanisms are poorly understood because of confounding among limiting factors. In fall 1998, research was initiated to determine the separate effects of above- and belowground competition and needlefall from overstory pines on understory plant performance. Three 13- to 15-yr-old plantations near Aiken, SC, were thinned to 0, 25, 50, or 100% of nonthinned basal area (19.5 m2 ha-1). Combinations of trenching (to eliminate root competition) and needlefall were applied to areas within each plot, and containerized seedlings of 14 perennial herbaceous species and longleaf pine were planted within each. Overstory crown closure ranged from 0 to 81%, and soil water and available nitrogen varied consistently with pine stocking, trenching, or their combination. Cover of planted species decreased an average of 16.5 and 14.1% as a result of above- and below-ground competition, respectively. Depending on species, needlefall effects were positive, negative, or negligible. Results indicate that understory restoration will be most successful when herbaceous species are established within canopy openings (0.1-0.2 ha) managed to minimize negative effects from above- and belowground competition and needlefall.

  2. Aboveground and belowground arthropods experience different relative influences of stochastic versus deterministic community assembly processes following disturbance

    Directory of Open Access Journals (Sweden)

    Scott Ferrenberg

    2016-10-01

    Full Text Available Background Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species and belowground (species active in organic and mineral soil layers arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community and modified Winkler funnels (belowground community and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies abundance, diversity, and composition. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models comparing observed vs. expected levels of species turnover (Beta diversity among samples. Results Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the

  3. Aboveground and belowground arthropods experience different relative influences of stochastic versus deterministic community assembly processes following disturbance

    Science.gov (United States)

    Martinez, Alexander S.; Faist, Akasha M.

    2016-01-01

    Background Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species) and belowground (species active in organic and mineral soil layers) arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community) and modified Winkler funnels (belowground community) and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies abundance, diversity, and composition. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models comparing observed vs. expected levels of species turnover (Beta diversity) among samples. Results Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the aboveground arthropod

  4. Global climate change and above- belowground insect herbivore interactions.

    Directory of Open Access Journals (Sweden)

    Scott Wesley McKenzie

    2013-10-01

    Full Text Available Predicted changes to the Earth’s climate are likely to affect above-belowground interactions. Our understanding is limited, however, by past focus on two-species aboveground interactions mostly ignoring belowground influences. Despite their importance to ecosystem processes, there remains a dearth of empirical evidence showing how climate change will affect above-belowground interactions. The responses of above- and belowground organisms to climate change are likely to differ given the fundamentally different niches they inhabit. Yet there are few studies that address the biological and ecological reactions of belowground herbivores to environmental conditions in current and future climates. Even fewer studies investigate the consequences of climate change for above-belowground interactions between herbivores and other organisms; those that do provide no evidence of a directed response. This paper highlights the importance of considering the belowground fauna when making predictions on the effects of climate change on plant-mediated interspecific interactions.

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

    Science.gov (United States)

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

    2017-12-01

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

  6. Belowground Carbon Cycling Processes at the Molecular Scale: An EMSL Science Theme Advisory Panel Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Hess, Nancy J.; Brown, Gordon E.; Plata, Charity

    2014-02-21

    As part of the Belowground Carbon Cycling Processes at the Molecular Scale workshop, an EMSL Science Theme Advisory Panel meeting held in February 2013, attendees discussed critical biogeochemical processes that regulate carbon cycling in soil. The meeting attendees determined that as a national scientific user facility, EMSL can provide the tools and expertise needed to elucidate the molecular foundation that underlies mechanistic descriptions of biogeochemical processes that control carbon allocation and fluxes at the terrestrial/atmospheric interface in landscape and regional climate models. Consequently, the workshop's goal was to identify the science gaps that hinder either development of mechanistic description of critical processes or their accurate representation in climate models. In part, this report offers recommendations for future EMSL activities in this research area. The workshop was co-chaired by Dr. Nancy Hess (EMSL) and Dr. Gordon Brown (Stanford University).

  7. Above- and below-ground responses of Calamagrostis purpurea to UV-B radiation and elevated CO{sub 2} under phosphorus limitation

    Energy Technology Data Exchange (ETDEWEB)

    Bussell, J.S.; Gwynn-Jones, D.; Griffith, G.W.; Scullion, J. (Aberystwyth Univ., IBERS, Wales (United Kingdom))

    2012-08-15

    UV-B radiation and elevated CO{sub 2} may impact rhizosphere processes through altered below-ground plant resource allocation and root exudation, changes that may have implications for nutrient acquisition. As nutrients limit plant growth in many habitats, their supply may dictate plant response under elevated CO{sub 2}. This study investigated UV-B exposure and elevated CO{sub 2} effects, including interactions, on plant growth, tissue chemistry and rooting responses relating to P acquisition. The sub-arctic grass Calamagrostis purpurea was subjected to UV-B (0 or 3.04 kJ m-2day-1) and CO{sub 2} (ambient 380 or 650 ppmv) treatments in a factorial glasshouse experiment, with sparingly soluble P (0 or 0.152 mg P per plant as FePO{sub 4}) a further factor. It was hypothesized that UV-B exposure and elevated CO{sub 2} would change plant resource allocation, with CO{sub 2} mitigating adverse responses to UV-B exposure and aiding P uptake. Plant biomass and morphology, tissue composition and rhizosphere leachate properties were measured. UV-B directly affected chemical composition of shoots and interacted with CO{sub 2} to give a greater root biomass. Elevated CO{sub 2} altered the composition of both shoots and roots and increased shoot biomass and secondary root length, while leachate pH decreased. Below-ground responses to CO{sub 2} did not affect P acquisition although P limitation progressively reduced leachate pH and increased secondary root length. Although direct plant growth, foliar composition and below-ground nutrient acquisition responses were dominated by CO{sub 2} treatments, UV-B modified these CO{sub 2} responses significantly. These interactions have implications for plant responses to future atmospheric conditions. (Author)

  8. Exploring the Influence of Topography on Belowground C Processes Using a Coupled Hydrologic-Biogeochemical Model

    Science.gov (United States)

    Shi, Y.; Davis, K. J.; Eissenstat, D. M.; Kaye, J. P.; Duffy, C.; Yu, X.; He, Y.

    2014-12-01

    Belowground carbon processes are affected by soil moisture and soil temperature, but current biogeochemical models are 1-D and cannot resolve topographically driven hill-slope soil moisture patterns, and cannot simulate the nonlinear effects of soil moisture on carbon processes. Coupling spatially-distributed physically-based hydrologic models with biogeochemical models may yield significant improvements in the representation of topographic influence on belowground C processes. We will couple the Flux-PIHM model to the Biome-BGC (BBGC) model. Flux-PIHM is a coupled physically-based land surface hydrologic model, which incorporates a land-surface scheme into the Penn State Integrated Hydrologic Model (PIHM). The land surface scheme is adapted from the Noah land surface model. Because PIHM is capable of simulating lateral water flow and deep groundwater, Flux-PIHM is able to represent the link between groundwater and the surface energy balance, as well as the land surface heterogeneities caused by topography. The coupled Flux-PIHM-BBGC model will be tested at the Susquehanna/Shale Hills critical zone observatory (SSHCZO). The abundant observations, including eddy covariance fluxes, soil moisture, groundwater level, sap flux, stream discharge, litterfall, leaf area index, above ground carbon stock, and soil carbon efflux, make SSHCZO an ideal test bed for the coupled model. In the coupled model, each Flux-PIHM model grid will couple a BBGC cell. Flux-PIHM will provide BBGC with soil moisture and soil temperature information, while BBGC provides Flux-PIHM with leaf area index. Preliminary results show that when Biome- BGC is driven by PIHM simulated soil moisture pattern, the simulated soil carbon is clearly impacted by topography.

  9. Below-ground process responses to elevated CO2 and temperature: a discussion of observations, measurement methods, and models

    Science.gov (United States)

    Elise Pendall; Scott Bridgham; Paul J. Hanson; Bruce Hungate; David W. Kicklighter; Dale W. Johnson; Beverly E. Law; Yiqi Luo; J. Patrick Megonigal; Maria Olsrud; Michael G. Ryan; Shiqiang Wan

    2004-01-01

    Rising atmospheric CO2 and temperatures are probably altering ecosystem carbon cycling, causing both positive and negative feedbacks to climate. Below-ground processes play a key role in the global carbon (C) cycle because they regulate storage of large quantities of C, and are potentially very sensitive to direct and indirect effects of elevated...

  10. Reduced growth due to belowground sink limitation is not fully explained by reduced photosynthesis.

    Science.gov (United States)

    Campany, Courtney E; Medlyn, Belinda E; Duursma, Remko A

    2017-08-01

    Sink limitation is known to reduce plant growth, but it is not known how plant carbon (C) balance is affected, limiting our ability to predict growth under sink-limited conditions. We manipulated soil volume to impose sink limitation of growth in Eucalyptus tereticornis Sm. seedlings. Seedlings were grown in the field in containers of different sizes and planted flush to the soil alongside freely rooted (Free) seedlings. Container volume negatively affected aboveground growth throughout the experiment, and light saturated rates of leaf photosynthesis were consistently lower in seedlings in containers (-26%) compared with Free seedlings. Significant reductions in photosynthetic capacity in containerized seedlings were related to both reduced leaf nitrogen content and starch accumulation, indicating direct effects of sink limitation on photosynthetic downregulation. After 120 days, harvested biomass of Free seedlings was on average 84% higher than seedlings in containers, but biomass distribution in leaves, stems and roots was not different. However, the reduction in net leaf photosynthesis over the growth period was insufficient to explain the reduction in growth, so that we also observed an apparent reduction in whole-plant C-use efficiency (CUE) between Free seedlings and seedlings in containers. Our results show that sink limitation affects plant growth through feedbacks to both photosynthesis and CUE. Mass balance approaches to predicting plant growth under sink-limited conditions need to incorporate both of these feedbacks. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Nitrogen soil emissions and belowground plant processes in Mediterranean annual pastures are altered by ozone exposure and N-inputs

    Science.gov (United States)

    Sánchez-Martín, L.; Bermejo-Bermejo, V.; García-Torres, L.; Alonso, R.; de la Cruz, A.; Calvete-Sogo, H.; Vallejo, A.

    2017-09-01

    Increasing tropospheric ozone (O3) and atmospheric nitrogen (N) deposition alter the structure and composition of pastures. These changes could affect N and C compounds in the soil that in turn can influence soil microbial activity and processes involved in the emission of N oxides, methane (CH4) and carbon dioxide (CO2), but these effects have been scarcely studied. Through an open top chamber (OTC) field experiment, the combined effects of both pollutants on soil gas emissions from an annual experimental Mediterranean community were assessed. Four O3 treatments and three different N input levels were considered. Fluxes of nitric (NO) and nitrous (N2O) oxide, CH4 and CO2 were analysed as well as soil mineral N and dissolved organic carbon. Belowground plant parameters like root biomass and root C and N content were also sampled. Ozone strongly increased soil N2O emissions, doubling the cumulative emission through the growing cycle in the highest O3 treatment, while N-inputs enhanced more slightly NO; CH4 and CO2 where not affected. Both N-gases had a clear seasonality, peaking at the start and at the end of the season when pasture physiological activity is minimal; thus, higher microorganism activity occurred when pasture had a low nutrient demand. The O3-induced peak of N2O under low N availability at the end of the growing season was counterbalanced by the high N inputs. These effects were related to the O3 x N significant interaction found for the root-N content in the grass and the enhanced senescence of the community. Results indicate the importance of the belowground processes, where competition between plants and microorganisms for the available soil N is a key factor, for understanding the ecosystem responses to O3 and N.

  12. Advancing Understanding of the Role of Belowground Processes in Terrestrial Carbon Sinks trhrough Ground-Penetrating Radar. Final Report

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    Day, Frank P. [Old Dominion Univ., Norfolk, VA (United States)

    2015-02-06

    Coarse roots play a significant role in belowground carbon cycling and will likely play an increasingly crucial role in belowground carbon sequestration as atmospheric CO2 levels continue to rise, yet they are one of the most difficult ecosystem parameters to quantify. Despite promising results with ground-penetrating radar (GPR) as a nondestructive method of quantifying biomass of coarse roots, this application of GPR is in its infancy and neither the complete potential nor limitations of the technology have been fully evaluated. The primary goals and questions of this study fell into four groups: (1) GPR methods: Can GPR detect change in root biomass over time, differentiate live roots from dead roots, differentiate between coarse roots, fine roots bundled together, and a fine root mat, remain effective with varied soil moisture, and detect shadowed roots (roots hidden below larger roots); (2) CO2 enrichment study at Kennedy Space Center in Brevard County, Florida: Are there post-fire legacy effects of CO2 fertilization on plant carbon pools following the end of CO2application ? (3) Disney Wilderness Study: What is the overall coarse root biomass and potential for belowground carbon storage in a restored longleaf pine flatwoods system? Can GPR effectively quantify coarse roots in soils that are wetter than the previous sites and that have a high percentage of saw palmetto rhizomes present? (4) Can GPR accurately represent root architecture in a three-dimensional model? When the user is familiar with the equipment and software in a setting that minimizes unsuitable conditions, GPR is a relatively precise, non-destructive, useful tool for estimating coarse root biomass. However, there are a number of cautions and guidelines that should be followed to minimize inaccuracies or situations that are untenable for GPR use. GPR appears to be precise as it routinely predicts highly similar values for a given area across multiple

  13. Relationships at the aboveground-belowground interface: plants, soil biota and soil processes

    NARCIS (Netherlands)

    Porazinska, D.L.; Bardgett, R.D.; Postma-Blaauw, M.B.; Hunt, H.W.; Parsons, A.N.; Seastedt, T.R.; Wall, D.M.

    2003-01-01

    Interactions at the aboveground-below ground interface provide important feedbacks that regulate ecosystem processes. Organisms within soil food webs are involved in processes of decomposition and nutrient mineralization, and their abundance and activity have been linked to plant ecophysiological

  14. Short- and longterm impacts of Acacia longifolia invasion on belowground processes of a Mediterranean coastal dune ecosystem

    DEFF Research Database (Denmark)

    Marchante, Elizabete; Kjøller, Annelise; Struwe, Sten

    2008-01-01

    to new areas, displacing the native vegetation. These invaded ecosystems contrast with the native dune ecosystems that are typically dominated by herb and shrub communities. This study characterizes belowground changes to the native environment as a result of recent (20 y...

  15. Information Processing and Limited Liability

    OpenAIRE

    Bartosz Mackowiak; Mirko Wiederholt

    2012-01-01

    Decision-makers often face limited liability and thus know that their loss will be bounded. We study how limited liability affects the behavior of an agent who chooses how much information to acquire and process in order to take a good decision. We find that an agent facing limited liability processes less information than an agent with unlimited liability. The informational gap between the two agents is larger in bad times than in good times and when information is more costly to process.

  16. Ecological linkages between aboveground and belowground biota

    NARCIS (Netherlands)

    Wardle, D.A.; Bardgett, R.D.; Klironomos, J.N.; Setälä, H.; Putten, van der W.H.; Wall, D.H.

    2004-01-01

    All terrestrial ecosystems consist of aboveground and belowground components that interact to influence community- and ecosystem-level processes and properties. Here we show how these components are closely interlinked at the community level, reinforced by a greater degree of specificity between

  17. Belowground Plant Dynamics Across an Arctic Landscape

    Science.gov (United States)

    Salmon, V. G.; Iversen, C. M.; Breen, A. L.; Thornton, P. E.; Wullschleger, S.

    2017-12-01

    High-latitude ecosystems are made up of a mosaic of different plant communities, all of which are exposed to warming at a rate double that observed in ecosystems at lower latitudes. Arctic regions are an important component of global Earth system models due to the large amounts of soil carbon (C) currently stored in permafrost as well their potential for increased plant C sequestration under warmer conditions. Losses of C from thawing and decomposing permafrost may be offset by increased plant productivity, but plant allocation to belowground structures and acquisition of limiting nutrients remain key sources of uncertainty in these ecosystems. The relationship between belowground plant traits and environmental conditions is not well understood, nor are tradeoffs between above- and belowground plant traits. To address these knowledge gaps, we sampled above- and belowground plant tissues along the Kougarok Hillslope on the Seward Peninsula, Alaska. The vegetation communities sampled included Alder shrubland, willow birch tundra, tussock tundra, dwarf shrub lichen tundra, and non-acidic mountain complex. Within each plant community, aboveground biomass was quantified and specific leaf area, leaf chemistry (%C, %N, %P and δ15N), and wood density were measured. Belowground fine-root biomass and rooting depth distribution were also determined at the community level. Fine roots from shrubs and graminoids were separated so that specific root area, diameter, and chemistry (%C, %N, %P and δ15N) could be assessed for these contrasting plant functional types. Initial findings indicate fine root biomass pools across the widely varying plant communities are constrained by soil depth, regardless of whether the rooting zone is restricted by permafrost or rock. The presence of Alnus viridis subspp. fruticosa, a deciduous shrub that facilitates nitrogen (N) fixation within its root nodules by Frankia bacteria, in Alder shrubland and willow birch tundra communities was associated

  18. Belowground Competition Directs Spatial Patterns of Seedling Growth in Boreal Pine Forests in Fennoscandia

    Directory of Open Access Journals (Sweden)

    E. Petter Axelsson

    2014-09-01

    Full Text Available Aboveground competition is often argued to be the main process determining patterns of natural forest regeneration. However, the theory of multiple resource limitation suggests that seedling performance also depends on belowground competition and, thus, that their relative influence is of fundamental importance. Two approaches were used to address the relative importance of above- and below-ground competition on regeneration in a nutrient-poor pine (Pinus sylvestris boreal forest. Firstly, seedling establishment beneath trees stem-girdled 12 years ago show that a substantial proportion of the seedlings were established within two years after girdling, which corresponds to a time when nutrient uptake by tree roots was severely reduced without disrupting water transport to the tree canopy, which consequently was maintained. The establishment during these two years also corresponds to abundances high enough for normal stand replacement. Secondly, surveys of regeneration within forest gaps showed that surrounding forests depressed seedlings, so that satisfactory growth occurred only more than 5 m from forest edges and that higher solar radiation in south facing edges was not enough to mediate these effects. We conclude that disruption of belowground competitive interactions mediates regeneration and, thus, that belowground competition has a strong limiting influence on seedling establishment in these forests.

  19. Total Belowground Carbon Allocation in a Fast-growing Eucalyptus Plantation Estimated Using a Carbon Balance Approach

    Science.gov (United States)

    Christian P. Giardina; Michael G. Ryan

    2002-01-01

    Trees allocate a large portion of gross primary production belowground for the production and maintenance of roots and mycorrhizae. The difficulty of directly measuring total belowground carbon allocation (TBCA) has limited our understanding of belowground carbon (C) cycling and the factors that control this important flux. We measured TBCA over 4 years using a...

  20. No consistent effect of plant species richness on resistance to simulated climate change for above- or below-ground processes in managed grasslands.

    Science.gov (United States)

    Dormann, Carsten F; von Riedmatten, Lars; Scherer-Lorenzen, Michael

    2017-06-17

    Species richness affects processes and functions in many ecosystems. Since management of temperate grasslands is directly affecting species composition and richness, it can indirectly govern how systems respond to fluctuations in environmental conditions. Our aim in this study was to investigate whether species richness in managed grasslands can buffer the effects of drought and warming manipulations and hence increase the resistance to climate change. We established 45 plots in three regions across Germany, each with three different management regimes (pasture, meadow and mown pasture). We manipulated spring warming using open-top chambers and summer drought using rain-out shelters for 4 weeks. Measurements of species richness, above- and below-ground biomass and soil carbon and nitrogen concentrations showed significant but inconsistent differences among regions, managements and manipulations. We detected a three-way interaction between species richness, management and region, indicating that our study design was sensitive enough to detect even intricate effects. We could not detect a pervasive effect of species richness on biomass differences between treatments and controls, indicating that a combination of spring warming and summer drought effects on grassland systems are not consistently moderated by species richness. We attribute this to the relatively high number of species even at low richness levels, which already provides the complementarity required for positive biodiversity-ecosystem functioning relationships. A review of the literature also indicates that climate manipulations largely fail to show richness-buffering, while natural experiments do, suggesting that such manipulations are milder than reality or incur treatment artefacts.

  1. The importance of aboveground–belowground interactions on the evolution and maintenance of variation in plant defense traits

    Science.gov (United States)

    van Geem, Moniek; Gols, Rieta; van Dam, Nicole M.; van der Putten, Wim H.; Fortuna, Taiadjana; Harvey, Jeffrey A.

    2013-01-01

    Over the past two decades a growing body of empirical research has shown that many ecological processes are mediated by a complex array of indirect interactions occurring between rhizosphere-inhabiting organisms and those found on aboveground plant parts. Aboveground–belowground studies have thus far focused on elucidating processes and underlying mechanisms that mediate the behavior and performance of invertebrates in opposite ecosystem compartments. Less is known about genetic variation in plant traits such as defense as that may be driven by above- and belowground trophic interactions. For instance, although our understanding of genetic variation in aboveground plant traits and its effects on community-level interactions is well developed, little is known about the importance of aboveground–belowground interactions in driving this variation. Plant traits may have evolved in response to selection pressures from above- and below-ground interactions from antagonists and mutualists. Here, we discuss gaps in our understanding of genetic variation in plant-related traits as they relate to aboveground and belowground multitrophic interactions. When metabolic resources are limiting, multiple attacks by antagonists in both domains may lead to trade-offs. In nature, these trade-offs may critically depend upon their effects on plant fitness. Natural enemies of herbivores may also influence selection for different traits via top–down control. At larger scales these interactions may generate evolutionary “hotspots” where the expression of various plant traits is the result of strong reciprocal selection via direct and indirect interactions. The role of abiotic factors in driving genetic variation in plant traits is also discussed. PMID:24348484

  2. Interactions between above- and belowground organisms modified in climate change experiments

    DEFF Research Database (Denmark)

    Stevnsbak, Karen; Scherber, Christoph; Gladbach, David

    2012-01-01

    Climate change has been shown to affect ecosystem process rates and community composition, with direct and indirect effects on belowground food webs. In particular, altered rates of herbivory under future climate4 can be expected to influence above–belowground interactions. Here, we use...... a multifactor, field-scale climate change experiment and independently manipulate atmospheric CO2 concentration, air and soil temperature and drought in all combinations since 2005. We show that changes in these factors modify the interaction between above- and belowground organisms.We use an insect herbivore...... a reduction in herbivory and cascading effects through the soil food web. Interactions between CO2, drought and warming can affect belowground protozoan abundance. Our findings imply that climate change affects aboveground–belowground interactions through changes in nutrient availability....

  3. Above and belowground connections and species interactions: Controls over ecosystem fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Trowbridge, Amy Marie [Montana State Univ., Bozeman, MT (United States); Phillips, Richard [Indiana Univ., Bloomington, IN (United States); Stoy, Paul Christopher [Montana State Univ., Bozeman, MT (United States)

    2016-11-01

    The ultimate goal of this work was to quantify soil and volatile organic compound fluxes as a function of tree species and associated mycorrhizal associations in an intact forest, but also to describe the physical and biological factors that control these emissions. The results of this research lay the foundation toward an improved mechanistic understanding of carbon pathways, fluxes, and ecosystem function, ultimately improving the representation of forest ecosystems in Earth System models. To this end, a multidisciplinary approach was necessary to fill a critical gap in our understanding of how soil and root processes may influence whole-ecosystem carbon-based volatile fluxes in the face of a rapidly changing climate. We developed a series of novel sampling protocols and coupled a variety of advanced analytical techniques, resulting in findings relevant across disciplines. Furthermore, we leveraged existing infrastructure, research sites, and datasets to design a low-cost exploratory project that links belowground processes, soil volatile emissions, and total ecosystem carbon budgets. Measurements from soil collars installed across a species/mycorrhizal gradient at the DOE-supported Moran Monroe State Forest Ameriflux tower site suggest that leaf litter is the primary source of belowground and forest floor volatile emissions, but the strength of this source is significantly affected not only by leaf litter type, but the strength of the soil as a sink. Results suggest that the strength of the sink is influenced by tree species-specific associated microbial communities that change throughout the season as a function of temperature, soil moisture, leaf litter inputs, and phenology. The magnitude of the observed volatile fluxes from the forest floor is small relative to total aboveground ecosystem flux, but the contribution of these emissions to volatile-mediated ecological interactions and soil processes (e.g. nitrification) varies substantially across the growing

  4. Belowground carabid beetle diversity in the western Palaearctic – effects of history and climate on range-restricted taxa (Coleoptera, Carabidae

    Directory of Open Access Journals (Sweden)

    Andreas Schuldt

    2011-05-01

    Full Text Available Broad-scale patterns of subterranean diversity are a fascinating but neglected part of biodiversity research. Carabid beetles adapted to belowground habitats form a particularly species-rich part of the subterranean fauna. We studied large-scale diversity patterns of these belowground carabids across the western Palaearctic and evaluated potential impacts of historical and contemporary environmental conditions on the distribution of these taxa, using available species richness and environmental data at country level. Regression modelling and variation partitioning showed a strong relationship between species richness and range in elevation. Potential effects of climatic variables, mainly those related to ambient energy input, were much weaker. We discuss the implications of this combination of effects, which suggests, concordant with the absence of subterranean carabids in northern and highest richness in southern Europe, a strong prevailing influence of historical processes on current richness distributions of these taxa. Previous studies did not provide clear indications for such an influence. In contrast to more mobile and widespread carabid beetles, dispersal limitation due to high adaptation of belowground carabids to subterranean habitats has probably hindered their re-colonization of former permafrost and glaciated regions. Hotspots of highest belowground diversity are located in regions with an assumed long-term stability of environmental conditions, correlating with patterns of other dispersal-limited taxa such as many endemic plants. Our study provides important new information in the discussion of potential determinants of the distinct geographic patterns of belowground diversity. Moreover, it contributes to a better understanding of range size related differences previously found in the distribution of diversity and environmental dependencies of widespread and range-restricted species within the highly diverse carabid beetles.

  5. Contribution of above- and below-ground plant traits to the structure and function of grassland soil microbial communities.

    Science.gov (United States)

    Legay, N; Baxendale, C; Grigulis, K; Krainer, U; Kastl, E; Schloter, M; Bardgett, R D; Arnoldi, C; Bahn, M; Dumont, M; Poly, F; Pommier, T; Clément, J C; Lavorel, S

    2014-10-01

    Abiotic properties of soil are known to be major drivers of the microbial community within it. Our understanding of how soil microbial properties are related to the functional structure and diversity of plant communities, however, is limited and largely restricted to above-ground plant traits, with the role of below-ground traits being poorly understood. This study investigated the relative contributions of soil abiotic properties and plant traits, both above-ground and below-ground, to variations in microbial processes involved in grassland nitrogen turnover. In mountain grasslands distributed across three European sites, a correlative approach was used to examine the role of a large range of plant functional traits and soil abiotic factors on microbial variables, including gene abundance of nitrifiers and denitrifiers and their potential activities. Direct effects of soil abiotic parameters were found to have the most significant influence on the microbial groups investigated. Indirect pathways via plant functional traits contributed substantially to explaining the relative abundance of fungi and bacteria and gene abundances of the investigated microbial communities, while they explained little of the variance in microbial activities. Gene abundances of nitrifiers and denitrifiers were most strongly related to below-ground plant traits, suggesting that they were the most relevant traits for explaining variation in community structure and abundances of soil microbes involved in nitrification and denitrification. The results suggest that consideration of plant traits, and especially below-ground traits, increases our ability to describe variation in the abundances and the functional characteristics of microbial communities in grassland soils. © 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.

  6. Materials and processing science: Limits for microelectronics

    Science.gov (United States)

    Rosenberg, R.

    1988-09-01

    The theme of this talk will be to illustrate examples of technologies that will drive materials and processing sciences to the limit and to describe some of the research being pursued to understand materials interactions which are pervasive to projected structure fabrication. It is to be expected that the future will see a progression to nanostructures where scaling laws will be tested and quantum transport will become more in evidence, to low temperature operation for tighter control and improved performance, to complex vertical profiles where 3D stacking and superlattices will produce denser packing and device flexibility, to faster communication links with optoelectronics, and to compatible packaging technologies. New low temperature processing techniques, such as epitaxy of silicon, PECVD of dielectrics, low temperature high pressure oxidation, silicon-germanium heterostructures, etc., must be combined with shallow metallurgies, new lithographic technologies, maskless patterning, rapid thermal processing (RTP) to produce needed profile control, reduce process incompatibilities and develop new device geometries. Materials interactions are of special consequence for chip substrates and illustrations of work in metal-ceramic and metal-polymer adhesion will be offered.

  7. Color management: printing processes - opportunities and limitations

    Science.gov (United States)

    Ingram, Samuel T.

    2002-06-01

    Digital tools have impacted traditional methods employed to reproduce color images during the past decade. The shift from a purely photomechanical process in color reproduction to colorimetric reproduction offers tremendous opportunity in the graphic arts industry. But good things do not necessarily come to all in the same package. Printing processes possess different reproduction attributes: tone reproduction, gray balance and color correction requirements are as different as the ingredient sets selected for color reproduction. This paper will provide insight toward understanding advantages and limitations offered by the new digital technologies in printing, publishing and packaging. For the past five years the Clemson University Graphic Communications Department has conducted numerous color projects using the new digital colorimetric tools during the previous decade. Several approaches have been used including experimental research and typical production workflows. The use of colorimetric data in color reproduction has given an opportunity to realize real gains in color use, predictability and consistency. Meeting an image's separation and reproduction requirements for a specified printing process can involve disruption of the anticipated workflow. Understanding the printing process requirements and the fit within the specifications of a colorimetric workflow are critical to the successful adoption of a color managed workflow. The paper will also provide an insight into the issues and challenges experienced with a color managed workflow. The printing processes used include offset litho, narrow and wide-web flexography (paper, liner board, corrugated and film), screen printing (paper board and polycarbonates), and digital imaging with toner, ink and inkjet systems. A proposal for technology integration will be the focus of the presentation drawn from documented experiences in over 300 applications of color management tools. Discussion will include the structure of

  8. Interactions between above- and belowground organisms modified in climate change experiments

    Science.gov (United States)

    Stevnbak, Karen; Scherber, Christoph; Gladbach, David J.; Beier, Claus; Mikkelsen, Teis N.; Christensen, Søren

    2012-11-01

    Climate change has been shown to affect ecosystem process rates and community composition, with direct and indirect effects on belowground food webs. In particular, altered rates of herbivory under future climate can be expected to influence above-belowground interactions. Here, we use a multifactor, field-scale climate change experiment and independently manipulate atmospheric CO2 concentration, air and soil temperature and drought in all combinations since 2005. We show that changes in these factors modify the interaction between above- and belowground organisms. We use an insect herbivore to experimentally increase aboveground herbivory in grass phytometers exposed to all eight combinations of climate change factors for three years. Aboveground herbivory increased the abundance of belowground protozoans, microbial growth and microbial nitrogen availability. Increased CO2 modified these links through a reduction in herbivory and cascading effects through the soil food web. Interactions between CO2, drought and warming can affect belowground protozoan abundance. Our findings imply that climate change affects aboveground-belowground interactions through changes in nutrient availability.

  9. Linking aboveground and belowground inducible plant resistance

    NARCIS (Netherlands)

    Bezemer, T.M.

    2009-01-01

    Induced resistance of plants against pests and diseases via plant defense responses is well documented and can occur aboveground, in the leaves, and belowground in the roots. A number of recent studies have shown that soil-borne pests can also induce plant resistance aboveground and vice versa.

  10. Limiting liability via high resolution image processing

    Energy Technology Data Exchange (ETDEWEB)

    Greenwade, L.E.; Overlin, T.K.

    1996-12-31

    The utilization of high resolution image processing allows forensic analysts and visualization scientists to assist detectives by enhancing field photographs, and by providing the tools and training to increase the quality and usability of field photos. Through the use of digitized photographs and computerized enhancement software, field evidence can be obtained and processed as `evidence ready`, even in poor lighting and shadowed conditions or darkened rooms. These images, which are most often unusable when taken with standard camera equipment, can be shot in the worst of photographic condition and be processed as usable evidence. Visualization scientists have taken the use of digital photographic image processing and moved the process of crime scene photos into the technology age. The use of high resolution technology will assist law enforcement in making better use of crime scene photography and positive identification of prints. Valuable court room and investigation time can be saved and better served by this accurate, performance based process. Inconclusive evidence does not lead to convictions. Enhancement of the photographic capability helps solve one major problem with crime scene photos, that if taken with standard equipment and without the benefit of enhancement software would be inconclusive, thus allowing guilty parties to be set free due to lack of evidence.

  11. [Digital thoracic radiology: devices, image processing, limits].

    Science.gov (United States)

    Frija, J; de Géry, S; Lallouet, F; Guermazi, A; Zagdanski, A M; De Kerviler, E

    2001-09-01

    In a first part, the different techniques of digital thoracic radiography are described. Since computed radiography with phosphore plates are the most commercialized it is more emphasized. But the other detectors are also described, as the drum coated with selenium and the direct digital radiography with selenium detectors. The other detectors are also studied in particular indirect flat panels detectors and the system with four high resolution CCD cameras. In a second step the most important image processing are discussed: the gradation curves, the unsharp mask processing, the system MUSICA, the dynamic range compression or reduction, the soustraction with dual energy. In the last part the advantages and the drawbacks of computed thoracic radiography are emphasized. The most important are the almost constant good quality of the pictures and the possibilities of image processing.

  12. Limits theorems for tail processes with applications tointermediate quantile estimation

    NARCIS (Netherlands)

    Einmahl, J.H.J.

    1992-01-01

    A description of the weak and strong limiting behaviour of weighted uniform tail empirical and tail quantile processes is given. The results for the tail quantile process are applied to obtain weak and strong functional limit theorems for a weighted non-uniform tail-quantile-type process based on a

  13. Links between belowground and aboveground resource-related traits reveal species growth strategies that promote invasive advantages.

    Science.gov (United States)

    Smith, Maria S; Fridley, Jason D; Goebel, Marc; Bauerle, Taryn L

    2014-01-01

    Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native) versus L. sempervirens (native) and Frangula alnus (non-native) versus Rhamnus alnifolia (native), over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

  14. Links between belowground and aboveground resource-related traits reveal species growth strategies that promote invasive advantages.

    Directory of Open Access Journals (Sweden)

    Maria S Smith

    Full Text Available Belowground processes are rarely considered in comparison studies of native verses invasive species. We examined relationships between belowground fine root production and lifespan, leaf phenology, and seasonal nitrogen dynamics of Lonicera japonica (non-native versus L. sempervirens (native and Frangula alnus (non-native versus Rhamnus alnifolia (native, over time. First and second order fine roots were monitored from 2010 to 2012 using minirhizotron technology and rhizotron windows. 15N uptake of fine roots was measured across spring and fall seasons. Significant differences in fine root production across seasons were seen between Lonicera species, but not between Frangula and Rhamnus, with both groups having notable asynchrony in regards to the timing of leaf production. Root order and the number of root neighbors at the time of root death were the strongest predictors of root lifespan of both species pairs. Seasonal 15N uptake was higher in spring than in the fall, which did not support the need for higher root activity to correspond with extended leaf phenology. We found higher spring 15N uptake in non-native L. japonica compared to native L. sempervirens, although there was no difference in 15N uptake between Frangula and Rhamnus species. Our findings indicate the potential for fast-growing non-native Lonicera japonica and Frangula alnus to outcompete native counterparts through differences in biomass allocation, root turnover, and nitrogen uptake, however evidence that this is a general strategy of invader dominance is limited.

  15. Positive responses of belowground C dynamics to nitrogen enrichment in China.

    Science.gov (United States)

    Deng, Lei; Peng, Changhui; Zhu, Guangyu; Chen, Lei; Liu, Yulin; Shangguan, Zhouping

    2018-03-01

    Determining how nitrogen (N) impacts ecosystem carbon (C) cycling is critical to using C sequestration to offset anthropogenic CO 2 emissions. The N deposition rate in China is higher than the global average; however, many results of N enrichment experiments in China have not been included in global syntheses. In this study, we assembled a large dataset that comprised 124 published studies concerning N addition experiments, including 570 observations at 127 sites across China, to quantify the responses of belowground C dynamics to N enrichment in terrestrial ecosystems in China by a meta-analysis. The results showed that overall soil organic C, dissolved organic C (DOC) and soil microbial biomass C (MBC) increased by 1.8, 7.4, and 8.8%, respectively (Penrichment; belowground biomass and litter increased by 14.6 and 24.4%, respectively (Penrichment promoted C inputs into the soil mainly by increasing litter and belowground biomass inputs. Additionally, N enrichment increased C output by increasing soil respiration. Land use type and N addition level had different impacts on the soil C pool and on soil respiration. DOC, MBC, and litter exhibited more positive responses to N deposition in cooler and more arid regions than in other regions. The meta-analysis indicated that N enrichment had a positive impact on belowground C cycles in China. Climate played a greater role than did N deposition level in affecting processes of ecosystem C cycling. Moreover, belowground C cycle processes are determined by complicated interactions among land use type, N enrichment, and climate. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Directory of Open Access Journals (Sweden)

    Sebastian Doetterl

    Full Text Available African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors.Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock were only half compared to an area with lower tree height (= smaller aboveground carbon stock. This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system.We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  17. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Science.gov (United States)

    Doetterl, Sebastian; Kearsley, Elizabeth; Bauters, Marijn; Hufkens, Koen; Lisingo, Janvier; Baert, Geert; Verbeeck, Hans; Boeckx, Pascal

    2015-01-01

    African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors. Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock) were only half compared to an area with lower tree height (= smaller aboveground carbon stock). This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system. We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  18. Some functional limit theorems for compound Cox processes

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, Victor Yu. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Institute of Informatics Problems FRC CSC RAS (Russian Federation); Chertok, A. V. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Euphoria Group LLC (Russian Federation); Korchagin, A. Yu. [Faculty of Computational Mathematics and Cybernetics, Moscow State University, Moscow (Russian Federation); Kossova, E. V. [Higher School of Economics National Research University, Moscow (Russian Federation); Zeifman, Alexander I. [Vologda State University, S.Orlova, 6, Vologda (Russian Federation); Institute of Informatics Problems FRC CSC RAS, ISEDT RAS (Russian Federation)

    2016-06-08

    An improved version of the functional limit theorem is proved establishing weak convergence of random walks generated by compound doubly stochastic Poisson processes (compound Cox processes) to Lévy processes in the Skorokhod space under more realistic moment conditions. As corollaries, theorems are proved on convergence of random walks with jumps having finite variances to Lévy processes with variance-mean mixed normal distributions, in particular, to stable Lévy processes.

  19. Some functional limit theorems for compound Cox processes

    International Nuclear Information System (INIS)

    Korolev, Victor Yu.; Chertok, A. V.; Korchagin, A. Yu.; Kossova, E. V.; Zeifman, Alexander I.

    2016-01-01

    An improved version of the functional limit theorem is proved establishing weak convergence of random walks generated by compound doubly stochastic Poisson processes (compound Cox processes) to Lévy processes in the Skorokhod space under more realistic moment conditions. As corollaries, theorems are proved on convergence of random walks with jumps having finite variances to Lévy processes with variance-mean mixed normal distributions, in particular, to stable Lévy processes.

  20. Investigation of density limit processes in DIII-D

    International Nuclear Information System (INIS)

    Maingi, R.; Mahdavi, M.A.; Petrie, T.W.

    1999-02-01

    A series of experiments has been conducted in DIII-D to investigate density-limiting processes. The authors have studied divertor detachment and MARFEs on closed field lines and find semi-quantitative agreement with theoretical calculations of onset conditions. They have shown that the critical density for MARFE onset at low edge temperature scales as I p /a 2 , i.e. similar to Greenwald scaling. They have also shown that the scaling of the critical separatrix density with heating power at partial detachment onset agrees with Borass' model. Both of these processes yield high edge density limits for reactors such as ITER. By using divertor pumping and pellet fueling they have avoided these and other processes and accessed densities > 1.5x Greenwald limit scaling with H-mode confinement, demonstrating that the Greenwald limit is not a fundamental limit on the core density

  1. Investigation of density limit processes in DIII-D

    International Nuclear Information System (INIS)

    Maingi, R.; Baylor, L.R.; Jernigan, T.

    2001-01-01

    A series of experiments has been conducted in DIII-D to investigate density-limiting processes. We have studied divertor detachment and MARFEs on closed field lines and find semi-quantitative agreement with theoretical calculations of onset conditions. We have shown that the critical density for MARFE onset at low edge temperature scales as I p /a 2 , i.e. similar to Greenwald scaling. We have also shown that the scaling of the critical separatrix density with heating power at partial detachment onset agrees with Borass' model. Both of these processes yield high edge density limits for reactors such as ITER. By using divertor pumping and pellet fueling we have avoided these and other processes and accessed densities >1.5x Greenwald limit scaling with H-mode confinement, demonstrating that the Greenwald limit is not a fundamental limit on the core density. (author)

  2. Investigation of density limit processes in DIII-D

    International Nuclear Information System (INIS)

    Maingi, R.; Mahdavi, M.A.; Petrie, T.W.

    1999-01-01

    A series of experiments has been conducted in DIII-D to investigate density-limiting processes. We have studied divertor detachment and MARFEs on closed field lines and find semi-quantitative agreement with theoretical calculations of onset conditions. We have shown that the critical density for MARFE onset at low edge temperature scales as I p /a 2 , i.e. similar to Greenwald scaling. We have also shown that the scaling of the critical separatrix density with heating power at partial detachment onset agrees with Borass' model. Both of these processes yield high edge density limits for reactors such as ITER. By using divertor pumping and pellet fueling we have avoided these and other processes and accessed densities > 1.5x Greenwald limit scaling with H-mode confinement, demonstrating that the Greenwald limit is not a fundamental limit on the core density. (author)

  3. Ultra-processed foods and the limits of product reformulation.

    Science.gov (United States)

    Scrinis, Gyorgy; Monteiro, Carlos Augusto

    2018-01-01

    The nutritional reformulation of processed food and beverage products has been promoted as an important means of addressing the nutritional imbalances in contemporary dietary patterns. The focus of most reformulation policies is the reduction in quantities of nutrients-to-limit - Na, free sugars, SFA, trans-fatty acids and total energy. The present commentary examines the limitations of what we refer to as 'nutrients-to-limit reformulation' policies and practices, particularly when applied to ultra-processed foods and drink products. Beyond these nutrients-to-limit, there are a range of other potentially harmful processed and industrially produced ingredients used in the production of ultra-processed products that are not usually removed during reformulation. The sources of nutrients-to-limit in these products may be replaced with other highly processed ingredients and additives, rather than with whole or minimally processed foods. Reformulation policies may also legitimise current levels of consumption of ultra-processed products in high-income countries and increased levels of consumption in emerging markets in the global South.

  4. Above- and below-ground competition in high and low irradiance: tree seedling responses to a competing liana Byttneria grandifolia

    NARCIS (Netherlands)

    Chen, J.Y.; Bongers, F.; Cao, K.F.; Cai, Z.Q.

    2008-01-01

    Abstract: In tropical forests, trees compete not only with other trees, but also with lianas, which may limit tree growth and regeneration. Liana effects may depend on the availability of above- and below-ground resources and differ between tree species. We conducted a shade house experiment to test

  5. Scaling Limits and Generic Bounds for Exploration Processes

    Science.gov (United States)

    Bermolen, Paola; Jonckheere, Matthieu; Sanders, Jaron

    2017-12-01

    We consider exploration algorithms of the random sequential adsorption type both for homogeneous random graphs and random geometric graphs based on spatial Poisson processes. At each step, a vertex of the graph becomes active and its neighboring nodes become blocked. Given an initial number of vertices N growing to infinity, we study statistical properties of the proportion of explored (active or blocked) nodes in time using scaling limits. We obtain exact limits for homogeneous graphs and prove an explicit central limit theorem for the final proportion of active nodes, known as the jamming constant, through a diffusion approximation for the exploration process which can be described as a unidimensional process. We then focus on bounding the trajectories of such exploration processes on random geometric graphs, i.e., random sequential adsorption. As opposed to exploration processes on homogeneous random graphs, these do not allow for such a dimensional reduction. Instead we derive a fundamental relationship between the number of explored nodes and the discovered volume in the spatial process, and we obtain generic bounds for the fluid limit and jamming constant: bounds that are independent of the dimension of space and the detailed shape of the volume associated to the discovered node. Lastly, using coupling techinques, we give trajectorial interpretations of the generic bounds.

  6. External and internal limitations in amplitude-modulation processing

    DEFF Research Database (Denmark)

    Ewert, Stephan; Dau, Torsten

    2004-01-01

    Three experiments are presented to explore the relative role of "external" signal variability and "internal" resolution limitations of the auditory system in the detection and discrimination of amplitude modulations (AM). In the first experiment, AM-depth discrimination performance was determined......-filterbank models. The predictions revealed that AM-depth discrimination and AM detection are limited by a combination of the external signal variability and an internal "Weber-fraction" noise process....

  7. Marsh Soil Responses to Nutrients: Belowground Structural and Organic Properties.

    Science.gov (United States)

    Coastal marsh responses to nutrient enrichment apparently depend upon soil matrix and whether the system is primarily biogenic or minerogenic. Deteriorating organic rich marshes (Jamaica Bay, NY) receiving wastewater effluent had lower belowground biomass, organic matter, and soi...

  8. Eliciting maize defense pathways aboveground attracts belowground biocontrol agents.

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S; Pereira, Ramom Vasconcelos; Moino Junior, Alcides; Pareja, Martin; Duncan, Larry W

    2016-11-04

    Plant defense pathways mediate multitrophic interactions above and belowground. Understanding the effects of these pathways on pests and natural enemies above and belowground holds great potential for designing effective control strategies. Here we investigate the effects of aboveground stimulation of plant defense pathways on the interactions between corn, the aboveground herbivore adult Diabrotica speciosa, the belowground herbivore larval D. speciosa, and the subterranean ento-mopathogenic nematode natural enemy Heterorhabditis amazonensis. We show that adult D. speciosa recruit to aboveground herbivory and methyl salicylate treatment, that larval D. speciosa are relatively indiscriminate, and that H. amazonensis en-tomopathogenic nematodes recruit to corn fed upon by adult D. speciosa. These results suggest that entomopathogenicnematodes belowground can be highly attuned to changes in the aboveground parts of plants and that biological control can be enhanced with induced plant defense in this and similar systems.

  9. Eliciting maize defense pathways aboveground attracts belowground biocontrol agents

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S.; Pereira, Ramom Vasconcelos; Moino Junior, Alcides; Pareja, Martin; Duncan, Larry W.

    2016-01-01

    Plant defense pathways mediate multitrophic interactions above and belowground. Understanding the effects of these pathways on pests and natural enemies above and belowground holds great potential for designing effective control strategies. Here we investigate the effects of aboveground stimulation of plant defense pathways on the interactions between corn, the aboveground herbivore adult Diabrotica speciosa, the belowground herbivore larval D. speciosa, and the subterranean ento-mopathogenic nematode natural enemy Heterorhabditis amazonensis. We show that adult D. speciosa recruit to aboveground herbivory and methyl salicylate treatment, that larval D. speciosa are relatively indiscriminate, and that H. amazonensis en-tomopathogenic nematodes recruit to corn fed upon by adult D. speciosa. These results suggest that entomopathogenicnematodes belowground can be highly attuned to changes in the aboveground parts of plants and that biological control can be enhanced with induced plant defense in this and similar systems. PMID:27811992

  10. Limiting processes in non-equilibrium classical statistical mechanics

    International Nuclear Information System (INIS)

    Jancel, R.

    1983-01-01

    After a recall of the basic principles of the statistical mechanics, the results of ergodic theory, the transient at the thermodynamic limit and his link with the transport theory near the equilibrium are analyzed. The fundamental problems put by the description of non-equilibrium macroscopic systems are investigated and the kinetic methods are stated. The problems of the non-equilibrium statistical mechanics are analyzed: irreversibility and coarse-graining, macroscopic variables and kinetic description, autonomous reduced descriptions, limit processes, BBGKY hierarchy, limit theorems [fr

  11. Scope and limitations of due process in administrative proceedings

    Directory of Open Access Journals (Sweden)

    Bernardo Carvajal Sánchez

    2010-12-01

    Full Text Available In order to explain in a better way the scope of Due Process in Administrative Law as a legal norm whose respect is essential to all government agencies, three points of view (formal, structural and material are proposed. Those items seem useful to understand “Administrative Due Process” in all its dimensions: as a constitutional norm developed by the enactment of laws and decrees; as a principle inspiring some conducts and new norms; and as an objective and subjective fundamental right. On the other hand, it is shown that Administrative Due Process is not an absolute rule because in some cases its full application is subject to normative relativism. Two opposite trends can be perceived at this point: in the first place, government agencies usually do not act the same way judges do, so Administrative Due Process should be distinguished from Judicial Due Process; therefore, it could actually have a more restricted scope. In the second place, some administrative authorities are nowadays playing a role more or less similar to what judges do. This means that new procedural guarantees will be claimed. In any case, admitting valid limitations to Administrative Due Process leads to the quest of the limits of these limitations. The application of the rule of Due Process cannot be totally suppressed; its scope cannot be completely reduced. This is the result of its fundamental nature as a legal norm that ensures justice and equity in all administrative procedures, and proscribes random decisions.

  12. Brownian Motion as a Limit to Physical Measuring Processes

    DEFF Research Database (Denmark)

    Niss, Martin

    2016-01-01

    In this paper, we examine the history of the idea that noise presents a fundamental limit to physical measuring processes. This idea had its origins in research aimed at improving the accuracy of instruments for electrical measurements. Out of these endeavors, the Swedish physicist Gustaf A. Ising...

  13. Processes limiting mussel bed restoration in the Wadden-Sea

    NARCIS (Netherlands)

    de Paoli, Helene; van de Koppel, Johan; van der Zee, Els; Kangeri, Arno; van Belzen, Jim; Holthuijsen, Sander; van den Berg, Aniek; Herman, Peter; Olff, Han; van der Heide, Tjisse

    This paper reports on experimental restoration of mussel beds in the Wadden Sea and the processes that might limit successful restoration of this foundation species (i.e. substrate, predation, hydrodynamics). The importance of substrate, predation, hydrodynamic conditions and location on mussel

  14. Limiting conditional distributions for birth-death processes

    NARCIS (Netherlands)

    Kijima, M.; Nair, M.G.; Pollett, P.K.; van Doorn, Erik A.

    1997-01-01

    In a recent paper one of us identified all of the quasi-stationary distributions for a non-explosive, evanescent birth-death process for which absorption is certain, and established conditions for the existence of the corresponding limiting conditional distributions. Our purpose is to extend these

  15. Belowground Carbon Allocation to Ectomycorrhizal Fungi Links Biogeochemical Cycles of Boron and Nitrogen

    Science.gov (United States)

    Lucas, R. W.; Högberg, P.; Ingri, J. N.

    2011-12-01

    Boron (B) is an essential micronutrient to most trees and represents an important limiting resource in some regions, deficient trees experiencing the loss of apical dominance, altered stem growth, and even tree death in extreme cases. Similar to the acquisition of most soil nutrients, B is likely supplied to host trees by mycorrhizal symbionts in exchange for recently fixed carbohydrates. In this way, belowground allocation of photosynthate, which drives the majority of biological processes belowground, links the biogeochemical cycles of B and nitrogen (N). Using a long-term N addition experiment in a Pinus sylvestris forest that has been ongoing for 41 years, we examined how the availability of inorganic N mediates the response of B isotopes in the tree needles, organic soil, and fungal pools in a boreal forest in northern Sweden. Using archived needle samples collected annually from the current year's needle crop, we observed δ11B to increase from 30.8 (0.5 se) to 41.8 (0.7 se)% in N fertilized plots from 1970 to 1979, a period of increasing B deficiency stress induced by N fertilization; the concentration of B in tree needles during 1979 dropping as low as 3.0 μg g-2. During the same period, B concentrations in tree needles from control plots remained relatively unchanged and δ11B remained at a steady state value of 34.1 (1.0 se)%. Following a distinct, large-scale, pulse labeling event in 1980 in which 2.5 kg ha-1 of isotopically distinct B was applied to all treatment and control plots to alleviate the N-induced B deficiency, concentrations of B in current needles increased immediately in all treatments, the magnitude of the response being dependent upon the N treatment. But unlike other pool dilution studies, δ11B of current tree needles did not return to pre-addition, steady-state levels. Instead, δ11B continued to decrease over time in both N addition and control treatments. This unexpected pattern has not been previously described but can be explained

  16. Functional State Modelling of Cultivation Processes: Dissolved Oxygen Limitation State

    Directory of Open Access Journals (Sweden)

    Olympia Roeva

    2015-04-01

    Full Text Available A new functional state, namely dissolved oxygen limitation state for both bacteria Escherichia coli and yeast Saccharomyces cerevisiae fed-batch cultivation processes is presented in this study. Functional state modelling approach is applied to cultivation processes in order to overcome the main disadvantages of using global process model, namely complex model structure and a big number of model parameters. Alongwith the newly introduced dissolved oxygen limitation state, second acetate production state and first acetate production state are recognized during the fed-batch cultivation of E. coli, while mixed oxidative state and first ethanol production state are recognized during the fed-batch cultivation of S. cerevisiae. For all mentioned above functional states both structural and parameter identification is here performed based on experimental data of E. coli and S. cerevisiae fed-batch cultivations.

  17. Above and belowground controls on litter decomposition in semiarid ecosystems: effects of solar radiation, water availability and litter quality

    Science.gov (United States)

    Austin, A. T.; Araujo, P. I.; Leva, P. E.; Ballare, C. L.

    2008-12-01

    The integrated controls on soil organic matter formation in arid and semiarid ecosystems are not well understood and appear to stem from a number of interacting controls affecting above- and belowground carbon turnover. While solar radiation has recently been shown to have an important direct effect on carbon loss in semiarid ecosystems as a result of photochemical mineralization of aboveground plant material, the mechanistic basis for photodegradative losses is poorly understood. In addition, there are large potential differences in major controls on above- and belowground decomposition in low rainfall ecosystems. We report on a mesocosm and field study designed to examine the relative importance of different wavelengths of solar radiation, water availability, position of senescent material above- and belowground and the importance of carbon litter quality in determining rates of abiotic and biotic decomposition. In a factorial experiment of mesocosms, we incubated leaf and root litter simultaneously above- and belowground and manipulated water availability with large and small pulses. Significant interactions between position-litter type and position-pulse sizes demonstrated interactive controls on organic mass loss. Aboveground decomposition showed no response to pulse size or litter type, as roots and leaves decomposed equally rapidly under all circumstances. In contrast, belowground decomposition was significantly altered by litter type and water pulses, with roots decomposing significantly slower and small water pulses reducing belowground decomposition. In the field site, using plastic filters which attenuated different wavelengths of natural solar radiation, we found a highly significant effect of radiation exclusion on mass loss and demonstrated that both UV-A and short-wave visible light can have important impacts on photodegradative carbon losses. The combination of position and litter quality effects on litter decomposition appear to be critical for the

  18. Short-term belowground responses to thinning and burning treatments in southwestern ponderosa pine forests of the USA

    Science.gov (United States)

    Steven T. Overby; Stephen C. Hart

    2016-01-01

    Microbial-mediated decomposition and nutrient mineralization are major drivers of forest productivity. As landscape-scale fuel reduction treatments are being implemented throughout the fire-prone western United States of America, it is important to evaluate operationally how these wildfire mitigation treatments alter belowground processes. We quantified these important...

  19. Thermodynamics at work - on the limits and potentials of biogeochemical processes

    Science.gov (United States)

    Peiffer, Stefan

    2017-04-01

    on the Fe and S side (Peiffer & Wan, 2016; Wan et al, 2014) which will allow for the occurrence of cryptic sulphur cycles, i. e. high turnover of sulphide and sulfate without the appearance of dissolved sulphide species. References Beer, J; Blodau, C (2007): Transport and thermodynamics constrain belowground carbon turover in a northern peatland, Geochim. Cosmochim. Acta, 71, 2989-3002 Blodau, C. (2002). "Carbon cycling in peatlands: A review of processes and controls." Environmental Reviews 10(2): 111-134. Blodau, C; Hoffmann, S; Peine, A; Peiffer, S (1998): Iron and sulfate reduction in the sediments of acid mine lake 116 (Brandenburg, Germany): Rates and geochemical evaluation, Water, Air and Soil Pollution, 108, 249-270 Peiffer, S., Wan M. (2016) Reductive Dissolution and Reactivity of Ferric (Hydr)oxides, in Faivre, D., Iron Oxides: From Nature to Applications, Wiley-VCH, chapter 3, 29-51 Peine, A; Küsel, K; Tritschler, A; Peiffer, S (2000): Electron flow in an iron-rich acidic sedimant - evidence for an acidity-driven iron cycle, Limnol. Oceanogr., 45(5), 1077-1087 Stumm, W.; Morgan, J. J. (1996): Aquatic Chemistry, Wiley Wan, M., Shchukarev, A., Lohmayer, R., Planer-Friedrich, B., Peiffer, S. (2014) Occurrence of surface polysulfides during the interaction between ferric (hydr)oxides and aqueous sulfide. Environmental Science and Technology, 48, 5076-5084

  20. A geomorphic process law for detachment-limited hillslopes

    Science.gov (United States)

    Turowski, Jens

    2015-04-01

    Geomorphic process laws are used to assess the shape evolution of structures at the Earth's surface over geological time scales, and are routinely used in landscape evolution models. There are two currently available concepts on which process laws for hillslope evolution rely. In the transport-limited concept, the evolution of a hillslope is described by a linear or a non-linear diffusion equation. In contrast, in the threshold slope concept, the hillslope is assumed to collapse to a slope equal to the internal friction angle of the material when the load due to the relief exists the material strength. Many mountains feature bedrock slopes, especially in the high mountains, and material transport along the slope is limited by the erosion of the material from the bedrock. Here, I suggest a process law for detachment-limited or threshold-dominated hillslopes, in which the erosion rate is a function of the applied stress minus the surface stress due to structural loading. The process law leads to the prediction of an equilibrium form that compares well to the shape of many mountain domes.

  1. Political Limits to the Processing of Policy Problems

    Directory of Open Access Journals (Sweden)

    Peter J. May

    2013-07-01

    Full Text Available This contribution addresses political limits to the processing of policy problems in the United States. Our foci are the forces that limit policymakers' attention to different aspects of problems and how this affects the prospects for problem resolution. We theorize about three sets of forces: interest engagement, linkages among relevant institutions for policymaking, and partisan conflict. We show how the interplay of these forces limits efforts to address complex problems. Based on secondary accounts, we consider these underlying dynamics for ten complex problems. These include the thorny problems of the financial crisis, climate change, and health care; the persistent problems of K-12 education, drug abuse, and food safety; and the looming problems associated with critical infrastructure, the obesity epidemic, ocean health, and terrorism and extreme events. From these accounts we identify different patterns that we label fractured, allied, bureaucratic, and anemic policymaking.

  2. Potential and Limitations of the Internet Use in Learning Process

    Directory of Open Access Journals (Sweden)

    D. Pavlovic

    2017-12-01

    Full Text Available The main research objective of this paper is to point out potentials and limitations of the Internet in the process of learning in higher education, through review and analysis of literature. The results of this theoretical study emphasize positive aspects of the Internet use in the learning process of university students that arise from the Internet features such as high technical capabilities, power, speed, universality and accessibility, as well as high sensitivity of young people to the means of new media. The positive effects of the applica-tion of the Internet were pointed out in research studies that analysed the pro-cess of innovation in higher education, the changes in the culture of learning, or certain aspects of personality development of university students. In contrast, some studies pointed out the limitations that may occur when using the Internet in the learning process related primarily to the credibility of the infor-mation, light and entertaining content dominance, and dependence on technology. Accordingly, it is recommended to adopt the measures on a larger scale that will affect the greater use of the Internet in the process of acquiring knowledge, especially in the field of higher education.

  3. About Hydrodynamic Limit of Some Exclusion Processes via Functional Integration

    OpenAIRE

    Fayolle , Guy; Furtlehner , Cyril

    2011-01-01

    Proceedings on CD. ISBN 978-5-901158-15-9; International audience; This article considers some classes of models dealing with the dynamics of discrete curves subjected to stochastic deformations. It turns out that the problems of interest can be set in terms of interacting exclusion processes, the ultimate goal being to derive hydrodynamic limits after proper scalings. A seemingly new method is proposed, which relies on the analysis of specific partial differential operators, involving variat...

  4. Unearthing belowground bud banks in fire-prone ecosystems.

    Science.gov (United States)

    Pausas, Juli G; Lamont, Byron B; Paula, Susana; Appezzato-da-Glória, Beatriz; Fidelis, Alessandra

    2018-03-01

    Despite long-time awareness of the importance of the location of buds in plant biology, research on belowground bud banks has been scant. Terms such as lignotuber, xylopodium and sobole, all referring to belowground bud-bearing structures, are used inconsistently in the literature. Because soil efficiently insulates meristems from the heat of fire, concealing buds below ground provides fitness benefits in fire-prone ecosystems. Thus, in these ecosystems, there is a remarkable diversity of bud-bearing structures. There are at least six locations where belowground buds are stored: roots, root crown, rhizomes, woody burls, fleshy swellings and belowground caudexes. These support many morphologically distinct organs. Given their history and function, these organs may be divided into three groups: those that originated in the early history of plants and that currently are widespread (bud-bearing roots and root crowns); those that also originated early and have spread mainly among ferns and monocots (nonwoody rhizomes and a wide range of fleshy underground swellings); and those that originated later in history and are strictly tied to fire-prone ecosystems (woody rhizomes, lignotubers and xylopodia). Recognizing the diversity of belowground bud banks is the starting point for understanding the many evolutionary pathways available for responding to severe recurrent disturbances. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  5. Estimating patterns in Spartina alterniflora belowground biomass within salt marshes

    Science.gov (United States)

    O'Connell, J. L.; Mishra, D. R.; Alber, M.; Byrd, K. B.

    2017-12-01

    Belowground biomass of marsh plants, such as Spartina alterniflora, help prevent marsh loss because they promote soil accretion, stabilize soils and add organic matter. However, site-wide estimates of belowground biomass are difficult to obtain because root:shoot ratios vary considerably both within species and across sites. We are working to develop a data fusion tool that can predict key characteristics of S. alterniflora, including belowground biomass and plant canopy N, based on satellite imagery. We used field observations from four salt marsh locations along the Georgia Coast, including one that is studied as part of the Georgia Coastal Ecosystems LTER project. From field and remote-sensing data, we developed a hybrid modeling approach to estimate % foliar N (a surrogate for plant assimilated nutrients). Partial Least squares (PLS) regression analysis of Landsat-8 spectral bands could predict variation in foliar N and belowground biomass, suggesting this public data source might be utilized for site-wide assessment of plant biophysical variables in salt marshes. Spectrally estimated foliar N and aboveground biomass were associated with belowground biomass and root:shoot ratio in S. alterniflora. This mirrors results from a previous study from the Sacramento-San Joaquin Delta, CA, on Scheonoplectus acutus, a marsh plant found in some tidal freshwater marshes. Therefore remote sensing may be a useful tool for measuring whole plant productivity among multiple coastal marsh species.

  6. The rate-limiting process of hydrogen transport in Mo

    Energy Technology Data Exchange (ETDEWEB)

    Ohkoshi, Keishiro; Chikazawa, Yoshitaka; Bandourko, V; Yamaguchi, Kenji; Yamawaki, Michio [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1996-10-01

    Hydrogen isotope transport characteristics of Mo, whose refractory properties are considered to be suitable as plasma facing material, was investigated by applying 3 keV D{sub 2}{sup +} beam to the membrane specimen. The Arrhenius plot of deuterium permeation probability showed linear increase against the reciprocal temperature and its apparent activation energy was determined as 41.5 kJ/mol. The simultaneous irradiation of 3 keV Ar{sup +} onto backside surface of specimen had little effect on the deuterium permeation rate. According to these results, the rate-limiting process of deuterium transport in Mo was determined. (author)

  7. Limitations of retarded (bisulfite) x-ray film processing

    International Nuclear Information System (INIS)

    Stoering, J.P.; Dittmore, C.

    1979-01-01

    We demonstrate the limitations of using retarded (bisulfite) developer to abate film sensitivity of x-ray films that have been exposed to intense radiation. We compared the measured densities of a large number of Kodak Type-M x-ray film samples exposed to a known fluence of monochromatic x-rays. These film samples were processed in three separate batches of bisulfite developer mixed in the same proportions. We concluded that reproducible film-density information cannot be obtained using different batches of (bisulfite) developer solutions

  8. Limit of grain refinement during ECAP process. Temperature influence

    International Nuclear Information System (INIS)

    Chuvil'deev, V.N.; Kopylov, V.I.; Nokhrin, A.V.; Makarov, I.M.; Lopatin, Yu.G.

    2004-01-01

    Experimental and theoretical study results are reported for the process of deformation grain refinement under severe plastic deformation. A generalization is made for experimental study results on deformation dispersing of unalloyed metals and aluminium and magnesium base alloys. The model is built that allows calculating the value of minimum grain size attained by the method of equal-channel angular pressing. The expressions are derived which describe the dependence of grain refinement limit on the nature of material and the temperature of severe plastic deformation [ru

  9. Large grazers modify effects of aboveground-belowground interactions on small-scale plant community composition

    NARCIS (Netherlands)

    Veen, G. F. (Ciska); Geuverink, Elzemiek; Olff, Han; Schmid, Bernhard

    Aboveground and belowground organisms influence plant community composition by local interactions, and their scale of impact may vary from millimeters belowground to kilometers aboveground. However, it still poorly understood how large grazers that select their forage on large spatial scales

  10. Large grazers modify effects of aboveground–belowground interactions on small-scale plant community composition

    NARCIS (Netherlands)

    Veen, G.F.; Geuverink, E.; Olff, H.

    2012-01-01

    Aboveground and belowground organisms influence plant community composition by local interactions, and their scale of impact may vary from millimeters belowground to kilometers aboveground. However, it still poorly understood how large grazers that select their forage on large spatial scales

  11. Belowground interactions with aboveground consequences: Invasive earthworms and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Paudel, Shishir; Longcore, Travis; MacDonald, Beau; McCormick, Melissa K; Szlavecz, Katalin; Wilson, Gail W T; Loss, Scot R

    2016-03-01

    A mounting body of research suggests that invasive nonnative earthworms substantially alter microbial communities, including arbuscular mycorrhizal fungi (AMF). These changes to AMF can cascade to affect plant communities and vertebrate populations. Despite these research advances, relatively little is known about (1) the mechanisms behind earthworms' effects on AMF and (2) the factors that determine the outcomes of earthworm-AMF interactions (i.e., whether AMF abundance is increased or decreased and subsequent effects on plants). We predict that AMF-mediated effects of nonnative earthworms on ecosystems are nearly universal because (1) AMF are important components of most terrestrial ecosystems, (2) nonnative earthworms have become established in nearly every type of terrestrial ecosystem, and (3) nonnative earthworms, due to their burrowing and feeding behavior, greatly affect AMF with potentially profound concomitant effects on plant communities. We highlight the multiple direct and indirect effects of nonnative earthworms on plants and review what is currently known about the interaction between earthworms and AMF. We also illustrate how the effects of nonnative earthworms on plant-AMF mutualisms can alter the structure and stability of aboveground plant communities, as well as the vertebrate communities relying on these habitats. Integrative studies that assess the interactive effects of earthworms and AMF can provide new insights into the role that belowground ecosystem engineers play in altering aboveground ecological processes. Understanding these processes may improve our ability to predict the structure of plant and animal communities in earthworm-invaded regions and to develop management strategies that limit the numerous undesired impacts of earthworms.

  12. Plant life history and above–belowground interactions

    NARCIS (Netherlands)

    Deyn, de Gerlinde

    2017-01-01

    The importance of above–belowground interactions for plant growth and community dynamics became clear in the last decades, whereas the numerous studies on plant life history improved our knowledge on eco-evolutionary dynamics. However, surprisingly few studies have linked both research fields

  13. Potential remobilization of belowground permafrost carbon under future global warming

    Science.gov (United States)

    P. Kuhry; E. Dorrepaal; G. Hugelius; E.A.G. Schuur; C. Tarnocai

    2010-01-01

    Research on permafrost carbon has dramatically increased in the past few years. A new estimate of 1672 Pg C of belowground organic carbon in the northern circumpolar permafrost region more than doubles the previous value and highlights the potential role of permafrost carbon in the Earth System. Uncertainties in this new estimate remain due to relatively few available...

  14. Local and global limits on visual processing in schizophrenia.

    Directory of Open Access Journals (Sweden)

    Marc S Tibber

    Full Text Available Schizophrenia has been linked to impaired performance on a range of visual processing tasks (e.g. detection of coherent motion and contour detection. It has been proposed that this is due to a general inability to integrate visual information at a global level. To test this theory, we assessed the performance of people with schizophrenia on a battery of tasks designed to probe voluntary averaging in different visual domains. Twenty-three outpatients with schizophrenia (mean age: 40±8 years; 3 female and 20 age-matched control participants (mean age 39±9 years; 3 female performed a motion coherence task and three equivalent noise (averaging tasks, the latter allowing independent quantification of local and global limits on visual processing of motion, orientation and size. All performance measures were indistinguishable between the two groups (ps>0.05, one-way ANCOVAs, with one exception: participants with schizophrenia pooled fewer estimates of local orientation than controls when estimating average orientation (p = 0.01, one-way ANCOVA. These data do not support the notion of a generalised visual integration deficit in schizophrenia. Instead, they suggest that distinct visual dimensions are differentially affected in schizophrenia, with a specific impairment in the integration of visual orientation information.

  15. Black hole emission process in the high energy limit

    Energy Technology Data Exchange (ETDEWEB)

    Carter, B [Observatoire de Paris, Section de Meudon, 92 (France). Groupe d' Astrophysique Relativiste; Gibbons, G W; Lin, D N.C.; Perry, M J [Cambridge Univ. (UK). Dept. of Applied Mathematics and Theoretical Physics; Cambridge Univ. (UK). Inst. of Astronomy)

    1976-11-01

    The ultimate outcome of the Hawking process of particle emission by small black holes is discussed in terms of the various conceivable theories of the behaviour of matter in the ultra-high temperature limit. It is shown that if high temperature matter is described by a relatively hard equation of state with an adiabatic index GAMMA greater than 6/5 then interactions between particles can probably be ignored so that the rate of creation will continue to be describable by Hawking's method. On the other hand for softer equations of state (including those of the ultra soft Hagedorn type) the created matter will almost certainly be highly opaque and a hydrodynamic model of the emission process will be more appropriate. Actual astronomical detection of the final emission products might in principle have provided valuable information about the correct theory of ultra high energy physics but it is shown that in practice the black hole death rate is so low that observational distinction of the resulting high energy decay products from the background would require high resolution detectors.

  16. Belowground advantages in construction cost facilitate a cryptic plant invasion.

    Science.gov (United States)

    Caplan, Joshua S; Wheaton, Christine N; Mozdzer, Thomas J

    2014-04-30

    The energetic cost of plant organ construction is a functional trait that is useful for understanding carbon investment during growth (e.g. the resource acquisition vs. tissue longevity tradeoff), as well as in response to global change factors like elevated CO2 and N. Despite the enormous importance of roots and rhizomes in acquiring soil resources and responding to global change, construction costs have been studied almost exclusively in leaves. We sought to determine how construction costs of aboveground and belowground organs differed between native and introduced lineages of a geographically widely dispersed wetland plant species (Phragmites australis) under varying levels of CO2 and N. We grew plants under ambient and elevated atmospheric CO2, as well as under two levels of soil nitrogen. We determined construction costs for leaves, stems, rhizomes and roots, as well as for whole plants. Across all treatment conditions, the introduced lineage of Phragmites had a 4.3 % lower mean rhizome construction cost than the native. Whole-plant construction costs were also smaller for the introduced lineage, with the largest difference in sample means (3.3 %) occurring under ambient conditions. In having lower rhizome and plant-scale construction costs, the introduced lineage can recoup its investment in tissue construction more quickly, enabling it to generate additional biomass with the same energetic investment. Our results suggest that introduced Phragmites has had an advantageous tissue investment strategy under historic CO2 and N levels, which has facilitated key rhizome processes, such as clonal spread. We recommend that construction costs for multiple organ types be included in future studies of plant carbon economy, especially those investigating global change. Published by Oxford University Press on behalf of the Annals of Botany Company.

  17. As above, so below? How the interplay between overstory species and edaphic factors influences the magnitude and mechanisms of belowground carbon cycles.

    Science.gov (United States)

    Desie, Ellen; Vancampenhout, Karen; Buelens, Jeroen; Verstraeten, Gorik; Verheyen, Kris; Heyens, Kathleen; Muys, Bart

    2017-04-01

    The choice of overstory species in relation to soil properties is one of the most important management decisions in forestry, especially when deciduous or mixed stands are replaced by coniferous monocultures. When assessed in relation to climate change, conversion effects are mainly studied in terms of total carbon stocks. These are generally considered to evolve linearly, according to similar stabilization processes across ecosystems. Here we show that the belowground carbon cycle is subject to ecosystem-specific stable process domains. The process domains are separated by steep thresholds, or even tipping points, where a small increase in environmental forcing can cause a drastic change in the way the ecosystem processes carbon. These effects are demonstrated in detail for the old-growth forest complex of the Gaume in Belgium. This forest spans a lithological gradient and mixed-species stands occur next to stands recently converted to Norway spruce (Picea abies) monocultures, creating a setting of paired plots that allow to address the magnitude of management choices relative to intrinsic natural potential. Vegetation descriptions, litter samples and soil samples at different depths were compared for above- and belowground functional biodiversity, litter layer characteristics, soil properties, nutrient status, bioturbation, soil carbon stocks and soil carbon functional pools. Results show that in soils with limited remaining buffer capacity, overstory-induced acidification under spruce causes a shift to an acid aluminum buffered environment, with a collapse in variability of abiotic and biotic soil properties. This entails a shift in soil fauna and depth relations, with a clear decoupling of the litter layer from the topsoil and the subsoil in terms of biological communities, carbon input and stochastic constraints. Finally, this study indicates that although spruce conversion increases the total soil carbon stocks, this extra carbon is stored in more labile

  18. The Limited Impact of Exposure Duration on Holistic Word Processing.

    Science.gov (United States)

    Chen, Changming; Abbasi, Najam Ul Hasan; Song, Shuang; Chen, Jie; Li, Hong

    2016-01-01

    The current study explored the impact of stimuli exposure duration on holistic word processing measured by the complete composite paradigm (CPc paradigm). The participants were asked to match the cued target parts of two characters which were presented for either a long (600 ms) or a short duration (170 ms). They were also tested by two popular versions of the CPc paradigm: the "early-fixed" task where the attention cue was visible from the beginning of each trial at a fixed position, and the "delayed-random" task where the cue showed up after the study character at random locations. The holistic word effect, as indexed by the alignment × congruency interaction, was identified in both tasks and was unaffected by the stimuli duration in both tasks. Meanwhile, the "delayed-random" task did not bring about larger holistic word effect than the "early-fixed" task. These results suggest the exposure duration (from around 150 to 600 ms) has a limited impact on the holistic word effect, and have methodological implications for experiment designs in this field.

  19. Designing an Iterative Learning Control Algorithm Based on Process History using limited post process geometrical information

    DEFF Research Database (Denmark)

    Endelt, Benny Ørtoft; Volk, Wolfram

    2013-01-01

    , there is a number of obstacles which need to be addressed before an industrial implementation is possible, e.g. the proposed control algorithms are often limited by the ability to sample process data with both sufficient accuracy and robustness - this lack of robust sampling technologies is one of the main barriers...

  20. Processing with kW fibre lasers: advantages and limits

    Science.gov (United States)

    Kratky, A.; Schuöcker, D.; Liedl, G.

    2008-10-01

    Up-to-date fibre lasers produce multi-kw radiation with an excellent beam quality. Compared to CO2-lasers, fibre lasers have relatively low operational costs and offer a very high flexibility in production due to the beam delivery with process fibres. As a consequence, fibre lasers have attracted more and more attention. On the other hand, their use in industrial applications especially in the automotive industry is still limited to a certain extent and fibre lasers haven't replaced all other laser sources till now as it could be expected. In laser cutting, the small kerf width produced by fibre lasers should be advantageous since the heated volume is smaller compared to CO2-lasers. In fact, cutting velocities are usually much higher which is also caused by the higher absorption coefficient of most metals at the wavelength emitted by fibre lasers. Nevertheless, cutting with fibre lasers of some metals - e.g. stainless steels - is restricted to a small thicknesses of approx. 5mm. The reason for this is that the surface roughness of the edges increases dramatically with the thickness of the work piece. Applications of fibre lasers include e.g. remote welding or even remote cutting of a large variety of materials with usually excellent results. Due to the excellent beam quality the aspect ratio of the weld seam in relation to the penetration depth is quite good. In the case of thin sheet metal welding such a small beam waist is beneficial - but with thicker sheet metals it is very often disadvantageous since the preparation of samples is more complicated, costs increase and requirements on clamping devices rise. In this paper, advantages and disadvantages of fibre lasers are discussed briefly. Applications of a 1.5 kW fibre laser are presented and compared to classical laser systems.

  1. Variability in above- and belowground carbon stocks in a Siberian larch watershed

    Directory of Open Access Journals (Sweden)

    E. E. Webb

    2017-09-01

    Full Text Available Permafrost soils store between 1330 and 1580 Pg carbon (C, which is 3 times the amount of C in global vegetation, almost twice the amount of C in the atmosphere, and half of the global soil organic C pool. Despite the massive amount of C in permafrost, estimates of soil C storage in the high-latitude permafrost region are highly uncertain, primarily due to undersampling at all spatial scales; circumpolar soil C estimates lack sufficient continental spatial diversity, regional intensity, and replication at the field-site level. Siberian forests are particularly undersampled, yet the larch forests that dominate this region may store more than twice as much soil C as all other boreal forest types in the continuous permafrost zone combined. Here we present above- and belowground C stocks from 20 sites representing a gradient of stand age and structure in a larch watershed of the Kolyma River, near Chersky, Sakha Republic, Russia. We found that the majority of C stored in the top 1 m of the watershed was stored belowground (92 %, with 19 % in the top 10 cm of soil and 40 % in the top 30 cm. Carbon was more variable in surface soils (10 cm; coefficient of variation (CV  =  0.35 between stands than in the top 30 cm (CV  =  0.14 or soil profile to 1 m (CV  =  0.20. Combined active-layer and deep frozen deposits (surface – 15 m contained 205 kg C m−2 (yedoma, non-ice wedge and 331 kg C m−2 (alas, which, even when accounting for landscape-level ice content, is an order of magnitude more C than that stored in the top meter of soil and 2 orders of magnitude more C than in aboveground biomass. Aboveground biomass was composed of primarily larch (53 % but also included understory vegetation (30 %, woody debris (11 % and snag (6 % biomass. While aboveground biomass contained relatively little (8 % of the C stocks in the watershed, aboveground processes were linked to thaw depth and

  2. Use of innovative groundcovers in Mediterranean afforestations: aerial and belowground effects in hybrid walnut.

    Directory of Open Access Journals (Sweden)

    Angelo Vitone

    2016-11-01

    Full Text Available Forest restoration in the Mediterranean area is particularly limited by water scarcity in summer and by weed competition, especially during the first years after establishment. The negative impact of these factors can be mitigated through environmentally friendly and cost-effective techniques which favour root development. This study describes the results of innovative weeding techniques in a reforestation carried out in a former agricultural field in Solsona, NE Spain, under Continental Mediterranean Sub-humid climate conditions. The tested weeding techniques included both novel groundcovers (based on prototypes built on a new biodegradable biopolymer, jute treated with resin and recycled rubber and reference techniques, i.e. herbicide application and polyethylene and commercial biofilm groundcovers. We studied the response of hybrid walnut (Juglans x intermedia to the application of these techniques during the first vegetative period in terms of survival, aerial growth and aboveground and belowground biomass allocation. The innovative groundcovers resulted generally in similar outcomes as the reference techniques with regard to tree survival and growth, and to better results in the case of belowground and, to a lesser extent, total tree biomass. Although preliminary, our results suggest that the tested novel groundcovers, notably the model based on treated jute, represent a promising alternative to plastic mulching and herbicide application in afforestation of agricultural lands in Mediterranean continental conditions. Besides these promising productive results, the novel groundcovers bring together relevant technical and environmental benefits, related to their use (not requiring removal or being reusable and composition, based on biodegradable or recycled materials.

  3. When CO2 kills: effects of magmatic CO2 flux on belowground biota at Mammoth Mountain, CA

    Science.gov (United States)

    McFarland, J.; Waldrop, M. P.; Mangan, M.

    2011-12-01

    The biomass, composition, and activity of the soil microbial community is tightly linked to the composition of the aboveground plant community. Microorganisms in aerobic surface soils, both free-living and plant-associated are largely structured by the availability of growth limiting carbon (C) substrates derived from plant inputs. When C availability declines following a catastrophic event such as the death of large swaths of trees, the number and composition of microorganisms in soil would be expected to decline and/or shift to unique microorganisms that have better survival strategies under starvation conditions. High concentrations of volcanic cold CO2 emanating from Mammoth Mountain near Horseshoe Lake on the southwestern edge of Long Valley Caldera, CA has resulted in a large kill zone of tree species, and associated soil microbial species. In July 2010, we assessed belowground microbial community structure in response to disturbance of the plant community along a gradient of soil CO2 concentrations grading from 80% (no plant life). We employed a microbial community fingerprinting technique (automated ribosomal intergenic spacer analysis) to determine changes in overall community composition for three broad functional groups: fungi, bacteria, and archaea. To evaluate changes in ectomycorrhizal fungal associates along the CO2 gradient, we harvested root tips from lodgepole pine seedlings collected in unaffected forest as well as at the leading edge of colonization into the kill zone. We also measured soil C fractions (dissolved organic C, microbial biomass C, and non-extractable C) at 10 and 30 cm depth, as well as NH4+. Not surprisingly, our results indicate a precipitous decline in soil C, and microbial C with increasing soil CO2; phospholipid fatty acid analysis in conjunction with community fingerprinting indicate both a loss of fungal diversity as well as a dramatic decrease in biomass as one proceeds further into the kill zone. This observation was

  4. 40 CFR Table 2 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Particulate Matter Emission Limits

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 13 2010-07-01 2010-07-01 false Operating Limits for Boilers and Process Heaters With Particulate Matter Emission Limits 2 Table 2 to Subpart DDDDD of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION...

  5. 40 CFR Table 4 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Hydrogen Chloride Emission Limits

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 13 2010-07-01 2010-07-01 false Operating Limits for Boilers and Process Heaters With Hydrogen Chloride Emission Limits 4 Table 4 to Subpart DDDDD of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS...

  6. Invasive soil organisms and their effects on belowground processes

    Science.gov (United States)

    Erik Lilleskov; Jr. Mac A. Callaham; Richard Pouyat; Jane E. Smith; Michael Castellano; Grizelle Gonzalez; D. Jean Lodge; Rachel Arango; Frederick. Green

    2010-01-01

    Invasive species have a wide range of effects on soils and their inhabitants. By altering soils, through their direct effects on native soil organisms (including plants), and by their interaction with the aboveground environment, invasive soil organisms can have dramatic effects on the environment, the economy and human health. The most widely recognized effects...

  7. Demographic processes limiting seedling recruitment in arid grassland restoration

    Science.gov (United States)

    Jeremy J. James; Tony J. Svejcar; Matthew J. Rinella

    2011-01-01

    Seeding is an important management tool in aridland restoration, but seeded species often fail to establish. Previous research has largely focused on the technical aspects of seeding with little effort directed at identifying demographic processes driving recruitment failures.

  8. Stochastic Modeling and Deterministic Limit of Catalytic Surface Processes

    DEFF Research Database (Denmark)

    Starke, Jens; Reichert, Christian; Eiswirth, Markus

    2007-01-01

    Three levels of modeling, microscopic, mesoscopic and macroscopic are discussed for the CO oxidation on low-index platinum single crystal surfaces. The introduced models on the microscopic and mesoscopic level are stochastic while the model on the macroscopic level is deterministic. It can......, such that in contrast to the microscopic model the spatial resolution is reduced. The derivation of deterministic limit equations is in correspondence with the successful description of experiments under low-pressure conditions by deterministic reaction-diffusion equations while for intermediate pressures phenomena...

  9. Hydrodynamic limit of a nongradient interacting particle process

    International Nuclear Information System (INIS)

    Wick, W.D.

    1989-01-01

    A simple example of a nongradient stochastic interacting particle system is analyzed. In this model, symmetric simple exclusion in one dimension in a periodic environment, the dynamical term in the Green-Kubo formula contributes to the bulk diffusion constant. The law of large numbers for the density field and the central limit theorem for the density fluctuation field are proven, and the Green-Kubo expression for the diffusion constant is computed exactly. The hydrodynamic equation for the model turns out to be linear

  10. Statistical Process Control: Going to the Limit for Quality.

    Science.gov (United States)

    Training, 1987

    1987-01-01

    Defines the concept of statistical process control, a quality control method used especially in manufacturing. Generally, concept users set specific standard levels that must be met. Makes the point that although employees work directly with the method, management is responsible for its success within the plant. (CH)

  11. Some limitations on processing materials in acoustic levitation devices

    Science.gov (United States)

    Oran, W. A.; Witherow, W. K.; Ross, B. B.; Rush, J. E.

    1979-01-01

    The spot heating of samples, suspended in an acoustic field, was investigated to determine if the technique could be used to process materials. A single axis resonance device operating in air at 25 C with an rms pressure maximum of 160 to 170 db was used in the experiments. The heat flow from a hot object suspended in a levitation node is dominated by the effects of the field, with the heat loss approximately 20 times larger than that due to natural convection. The acoustic forces which suspend the body at a node also serve to eject the heated air. The coupling between the locally heated region around the body and the acoustic field results in instabilities in both the pressure wave and force field. The investigations indicated the extreme difficulties in developing a materials processing device based on acoustic/spot heating for use in a terrestrial environment.

  12. Is the Levels of Processing effect language-limited?

    OpenAIRE

    Baddeley, Alan David; Hitch, Graham James

    2017-01-01

    The concept of Levels of Processing (LOP), proposing that deep coding enhances retention,has played a central role in the study of episodic memory. Evidence has however been based almost entirely on retention of individual words. Across five experiments, we compare LOP effects between visual and verbal stimuli, using judgments of pleasantness as a method of inducing deep encoding and a range of shallow encoding judgments selected so as to be applicable to both verbal and visual stimuli. LOP e...

  13. Empirical and theoretical challenges in aboveground-belowground ecology

    DEFF Research Database (Denmark)

    W.H. van der Putten,; R.D. Bardgett; P.C. de Ruiter

    2009-01-01

    of the current conceptual succession models into more predictive models can help targeting empirical studies and generalising their results. Then, we discuss how understanding succession may help to enhance managing arable crops, grasslands and invasive plants, as well as provide insights into the effects...... and environmental settings, we explore where and how they can be supported by theoretical approaches to develop testable predictions and to generalise empirical results. We review four key areas where a combined aboveground-belowground approach offers perspectives for enhancing ecological understanding, namely...

  14. Downlink Multicell Processing with Limited-Backhaul Capacity

    Directory of Open Access Journals (Sweden)

    O. Simeone

    2009-01-01

    Full Text Available Multicell processing in the form of joint encoding for the downlink of a cellular system is studied under the assumption that the base stations (BSs are connected to a central processor (CP via finitecapacity links (finite-capacity backhaul. To obtain analytical insight into the impact of finite-capacity backhaul on the downlink throughput, the investigation focuses on a simple linear cellular system (as for a highway or a long avenue based on theWyner model. Several transmission schemes are proposed that require varying degrees of knowledge regarding the system codebooks at the BSs. Achievable rates are derived in closed-form and compared with an upper bound. Performance is also evaluated in asymptotic regimes of interest (high backhaul capacity and extreme signal-to-noise ratio, SNR and further corroborated by numerical results. The major finding of this work is that even in the presence of oblivious BSs (that is, BSs with no information about the codebooks multicell processing is able to provide ideal performance with relatively small backhaul capacities, unless the application of interest requires high data rate (i.e., high SNR and the backhaul capacity is not allowed to increase with the SNR. In these latter cases, some form of codebook information at the BSs becomes necessary.

  15. Marital Processes, Arranged Marriage, and Contraception to Limit Fertility

    Science.gov (United States)

    Ghimire, Dirgha J.; Axinn, William G.

    2013-01-01

    An international transition away from familially-arranged marriages toward participation in spouse choice has endured for decades and continues to spread through rural Asia today. Though we know this transformation has important consequences for childbearing early in marriage, we know much less about longer-term consequences of this marital revolution. This study draws upon theories of family and fertility change and a rural Asian panel study designed to investigate changes in both marital and childbearing behaviors to investigate these long-term consequences. Controlling for social changes that shape both marital practices and childbearing behaviors, and explicitly considering multiple dimensions of marital processes, we find evidence consistent with an independent, long-standing association of participation in spouse choice with higher rates of contraception to terminate childbearing. These results add a new dimension to the evidence linking revolutions in marital behavior to long-term declines in fertility, but also motivate new research to consider a broader range of long-term consequences of changing marital processes. PMID:23709184

  16. Detection limit for rate fluctuations in inhomogeneous Poisson processes

    Science.gov (United States)

    Shintani, Toshiaki; Shinomoto, Shigeru

    2012-04-01

    Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

  17. Detection limit for rate fluctuations in inhomogeneous Poisson processes.

    Science.gov (United States)

    Shintani, Toshiaki; Shinomoto, Shigeru

    2012-04-01

    Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

  18. An orthographic effect in phoneme processing, and its limitations

    Directory of Open Access Journals (Sweden)

    Anne eCutler

    2012-02-01

    Full Text Available To examine whether lexically stored knowledge about spelling influences phoneme evaluation, we conducted three experiments with a low-level phonetic judgement task: phoneme goodness rating. In each experiment, listeners heard phonetic tokens varying along a continuum centred on /s/, occurring finally in isolated word or nonword tokens. An effect of spelling appeared in Experiment 1: Native English speakers’ goodness ratings for the best /s/ tokens were significantly higher in words spelled with S (e.g., bless than in words spelled with C (e.g., voice. No such difference appeared when nonnative speakers rated the same materials in Experiment 2, indicating that the difference could not be due to acoustic characteristics of the S- versus C-words. In Experiment 3, nonwords with lexical neighbours consistently spelled with S (e.g., pless versus with C (e.g., floice failed to elicit orthographic neighbourhood effects; no significant difference appeared in native English speakers’ ratings for the S-consistent versus the C-consistent sets. Obligatory influence of lexical knowledge on phonemic processing would have predicted such neighbourhood effects; the findings are thus better accommodated by models in which phonemic decisions draw strategically upon lexical information.

  19. Effects of Soil Texture on Belowground Carbon and Nutrient Storage in a Lowland Amazonian Forest Ecosystem.

    Science.gov (United States)

    Whendee L. Silver; Jason Neff; Megan McGroddy; Ed Veldkamp; Michael Keller; Raimundo Cosme

    2000-01-01

    Soil texture plays a key role in belowground C storage in forest ecosystems and strongly influences nutrient availability and retention, particularly in highly weathered soils. We used field data and the Century ecosystem model to explore the role of soil texture in belowground C storage, nutrient pool sizes, and N fluxes in highly weathered soils in an Amazonian...

  20. Altered belowground carbon cycling following land use change to perennial bioenergy crops

    Science.gov (United States)

    Belowground carbon (C) dynamics of terrestrial ecosystems play an important role in the global C cycle and thereby in climate regulation, yet remain poorly understood. Globally, land use change is a major driver of changes in belowground C storage; in general, land clearing and tillage for agricult...

  1. Morchella tomentosa: a unique belowground structure and a new clade of morels

    Science.gov (United States)

    Franck O.P. Stefani; Serge Sokolski; Trish L. Wurtz; Yves Piché; Richard C. Hamelin; J. André Fortin; Jean A. Bérubé

    2010-01-01

    Mechanisms involved in post-fire morel fructification remain unclear. A new undescribed belowground vegetative structure of Marchella tomentosa in a burned boreal forest was investigated north of Fairbanks, Alaska. The name "radiscisclerotium" is proposed to define this peculiar and elaborate belowground vegetative structure of ...

  2. Use of belowground growing degree days to predict rooting of dormant hardwood cuttings of Populus

    Science.gov (United States)

    R.S., Jr. Zalesny; E.O. Bauer; D.E. Riemenschneider

    2004-01-01

    Planting Populus cuttings based on calendar days neglects soil temperature extremes and does not promote rooting based on specific genotypes. Our objectives were to: 1) test the biological efficacy of a thermal index based on belowground growing degree days (GDD) across the growing period, 2) test for interactions between belowground GDD and clones,...

  3. Belowground competition from overstory trees influences Douglas-fir sapling morphology in thinned stands

    Science.gov (United States)

    Warren D. Devine; Timothy B. Harrington

    2009-01-01

    We evaluated effects of belowground competition on morphology of naturally established coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) saplings in 60- to 80-year-old thinned Douglas-fir stands in southwestern Washington. We separately quantified belowground competition from overstory and understory sources...

  4. Plant neighbour identity matters to belowground interactions under controlled conditions.

    Science.gov (United States)

    Armas, Cristina; Pugnaire, Francisco Ignacio

    2011-01-01

    Root competition is an almost ubiquitous feature of plant communities with profound effects on their structure and composition. Far beyond the traditional view that plants interact mainly through resource depletion (exploitation competition), roots are known to be able to interact with their environment using a large variety of mechanisms that may inhibit or enhance access of other roots to the resource or affect plant growth (contest interactions). However, an extensive analysis on how these contest root interactions may affect species interaction abilities is almost lacking. In a common garden experiment with ten perennial plant species we forced pairs of plants of the same or different species to overlap their roots and analyzed how belowground contest interactions affected plant performance, biomass allocation patterns, and competitive abilities under abundant resource supply. Our results showed that net interaction outcome ranged from negative to positive, affecting total plant mass and allocation patterns. A species could be a strong competitor against one species, weaker against another one, and even facilitator to a third species. This leads to sets of species where competitive hierarchies may be clear but also to groups where such rankings are not, suggesting that intransitive root interactions may be crucial for species coexistence. The outcome of belowground contest interactions is strongly dependent on neighbours' identity. In natural plant communities this conditional outcome may hypothetically help species to interact in non-hierarchical and intransitive networks, which in turn might promote coexistence.

  5. Aboveground mechanical stimuli affect belowground plant-plant communication.

    Science.gov (United States)

    Elhakeem, Ali; Markovic, Dimitrije; Broberg, Anders; Anten, Niels P R; Ninkovic, Velemir

    2018-01-01

    Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution) or untouched plants (C_solution). The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

  6. Aboveground mechanical stimuli affect belowground plant-plant communication.

    Directory of Open Access Journals (Sweden)

    Ali Elhakeem

    Full Text Available Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution or untouched plants (C_solution. The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

  7. CRITICALITY SAFETY LIMIT EVALUATION PROGRAM (CSLEP's) AND QUICK SCREENS: ANSWERS TO EXPEDITED PROCESSING LEGACY CRITICALITY SAFETY LIMITS AND EVALUATIONS

    International Nuclear Information System (INIS)

    TOFFER, H.

    2006-01-01

    Since the end of the cold war, the need for operating weapons production facilities has faded. Criticality Safety Limits and controls supporting production modes in these facilities became outdated and furthermore lacked the procedure based rigor dictated by present day requirements. In the past, in many instances, the formalism of present day criticality safety evaluations was not applied. Some of the safety evaluations amounted to a paragraph in a notebook with no safety basis and questionable arguments with respect to double contingency criteria. When material stabilization, clean out, and deactivation activities commenced, large numbers of these older criticality safety evaluations were uncovered with limits and controls backed up by tenuous arguments. A dilemma developed: on the one hand, cleanup activities were placed on very aggressive schedules; on the other hand, a highly structured approach to limits development was required and applied to the cleanup operations. Some creative approaches were needed to cope with the limits development process

  8. Disruption of a belowground mutualism alters interactions between plants and their floral visitors.

    Science.gov (United States)

    Cahill, James F; Elle, Elizabeth; Smith, Glen R; Shore, Bryon H

    2008-07-01

    Plants engage in diverse and intimate interactions with unrelated taxa. For example, aboveground floral visitors provide pollination services, while belowground arbuscular mycorrhizal fungi (AMF) enhance nutrient capture. Traditionally in ecology, these processes were studied in isolation, reinforcing the prevailing assumption that these above- and belowground processes were also functionally distinct. More recently, there has been a growing realization that the soil surface is not a barrier to many ecological interactions, particularly those involving plants (who live simultaneously above and below ground). Because of the potentially large impact that mycorrhizae and floral visitors can have on plant performance and community dynamics, we designed an experiment to test whether these multi-species mutualisms were interdependent under field conditions. Using benomyl, a widely used fungicide, we suppressed AMF in a native grassland, measuring plant, fungal, and floral-visitor responses after three years of fungal suppression. AMF suppression caused a shift in the community of floral visitors from large-bodied bees to small-bodied bees and flies, and reduced the total number of floral visits per flowering stem 67% across the 23 flowering species found in the plots. Fungal suppression has species-specific effects on floral visits for the six most common flowering plants in this experiment. Exploratory analyses suggest these results were due to changes in floral-visitor behavior due to altered patch-level floral display, rather than through direct effects of AMF suppression on floral morphology. Our findings indicate that AMF are an important, and overlooked, driver of floral-visitor community structure with the potential to affect pollination services. These results support the growing body of research indicating that interactions among ecological interactions can be of meaningful effect size under natural field conditions and may influence individual performance

  9. Early root overproduction not triggered by nutrients decisive for competitive success belowground.

    Directory of Open Access Journals (Sweden)

    Francisco M Padilla

    Full Text Available Theory predicts that plant species win competition for a shared resource by more quickly preempting the resource in hotspots and by depleting resource levels to lower concentrations than its competitors. Competition in natural grasslands largely occurs belowground, but information regarding root interactions is limited, as molecular methods quantifying species abundance belowground have only recently become available.In monoculture, the grass Festuca rubra had higher root densities and a faster rate of soil nitrate depletion than Plantago lanceolata, projecting the first as a better competitor for nutrients. However, Festuca lost in competition with Plantago. Plantago not only replaced the lower root mass of its competitor, but strongly overproduced roots: with only half of the plants in mixture than in monoculture, Plantago root densities in mixture were similar or higher than those in its monocultures. These responses occurred equally in a nutrient-rich and nutrient-poor soil layer, and commenced immediately at the start of the experiment when root densities were still low and soil nutrient concentrations high.Our results suggest that species may achieve competitive superiority for nutrients by root growth stimulation prior to nutrient depletion, induced by the presence of a competitor species, rather than by a better ability to compete for nutrients per se. The root overproduction by which interspecific neighbors are suppressed independent of nutrient acquisition is consistent with predictions from game theory. Our results emphasize that root competition may be driven by other mechanisms than is currently assumed. The long-term consequences of these mechanisms for community dynamics are discussed.

  10. The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information.

    Science.gov (United States)

    Miller, George A.

    1994-01-01

    Capacity limitations in absolute judgment tasks are discussed in relation to information theory. Information theory can provide a quantitative way of resolving questions about limitations on the amount of information we can receive and the process of recoding. (SLD)

  11. 40 CFR 63.7506 - Do any boilers or process heaters have limited requirements?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 13 2010-07-01 2010-07-01 false Do any boilers or process heaters have..., and Institutional Boilers and Process Heaters General Compliance Requirements § 63.7506 Do any boilers or process heaters have limited requirements? (a) New or reconstructed boilers and process heaters in...

  12. 40 CFR 63.494 - Back-end process provisions-residual organic HAP limitations.

    Science.gov (United States)

    2010-07-01

    ... organic HAP limitations. 63.494 Section 63.494 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 63.494 Back-end process provisions—residual organic HAP limitations. (a) The monthly weighted average residual organic HAP content of all grades of elastomer processed, measured after the stripping operation...

  13. Early root overproduction not triggered by nutrients decisive for competitive success belowground

    NARCIS (Netherlands)

    Padilla, F.M.; Mommer, L.; Caluwe, de H.; Smit-Tiekstra, A.E.; Wagemaker, C.A.M.; Ouborg, N.J.; Kroon, de H.

    2013-01-01

    Background - Theory predicts that plant species win competition for a shared resource by more quickly preempting the resource in hotspots and by depleting resource levels to lower concentrations than its competitors. Competition in natural grasslands largely occurs belowground, but information

  14. Proceedings - Limits of Acceptable Change and related planning processes: Progress and future directions

    Science.gov (United States)

    Stephen F. McCool; David N. Cole

    1997-01-01

    Experience with Limits of Acceptable Change (LAC) and related planning processes has accumulated since the mid-1980's. These processes were developoed as a means of dealing with recreation carrying capacity issues in wilderness and National Parks. These processes clearly also have application outside of protected areas and to issues other than recreation...

  15. Agora: A proposal to overcome the limitations of the current knowledge creation process

    OpenAIRE

    ScientistFive

    2015-01-01

    Agora: A proposal to overcome the limitations of the current knowledge creation process ======================================================================================= By Scientistsfive () Abstract: The knowledge creation process is broken and can be improved by a combination of currently emerging tools. The rationale for this proposal is the notion that the current scientific process is not optimal: * Artificially staged competitions (g...

  16. 29 CFR 780.806 - Exempt ginning limited to first processing.

    Science.gov (United States)

    2010-07-01

    ... cottonseed, is not exempt under section 13(b)(15). It is not first processing of the seed cotton; rather, it... 29 Labor 3 2010-07-01 2010-07-01 false Exempt ginning limited to first processing. 780.806 Section... AGRICULTURE, PROCESSING OF AGRICULTURAL COMMODITIES, AND RELATED SUBJECTS UNDER THE FAIR LABOR STANDARDS ACT...

  17. Above- and Belowground Biomass Allocation in Shrub Biomes across the Northeast Tibetan Plateau

    Science.gov (United States)

    Yang, Yuanhe; Yang, Lucun; Zhou, Guoying

    2016-01-01

    Biomass partitioning has been explored across various biomes. However, the strategies of allocation in plants still remain contentious. This study investigated allocation patterns of above- and belowground biomass at the community level, using biomass survey from the Tibetan Plateau. We explored above- and belowground biomass by conducting three consecutive sampling campaigns across shrub biomes on the northeast Tibetan Plateau during 2011–2013. We then documented the above-ground biomass (AGB), below-ground biomass (BGB) and root: shoot ratio (R/S) and the relationships between R/S and environment factors using data from 201 plots surveyed from 67 sites. We further examined relationships between above-ground and below-ground biomass across various shrub types. Our results indicated that the median values of AGB, BGB, and R/S in Tibetan shrub were 1102.55, 874.91 g m-2, and 0.85, respectively. R/S showed significant trend with mean annual precipitation (MAP), while decreased with mean annual temperature (MAT). Reduced major axis analysis indicated that the slope of the log-log relationship between above- and belowground biomass revealed a significant difference from 1.0 over space, supporting the optimal hypothesis. Interestingly, the slopes of the allometric relationship between log AGB and log BGB differed significantly between alpine and desert shrub. Our findings supported the optimal theory of above- and belowground biomass partitioning in Tibetan shrub, while the isometric hypothesis for alpine shrub at the community level. PMID:27119379

  18. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta Forests.

    Directory of Open Access Journals (Sweden)

    Anne C S McIntosh

    Full Text Available Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs and multiple carbon-source substrate-induced respiration (MSIR of the forest floor microbial community environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis showed that two above-ground (mean tree diameter, litter cover and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs properties were associated with variation in understory plant community composition. These results provide

  19. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta) Forests.

    Science.gov (United States)

    McIntosh, Anne C S; Macdonald, S Ellen; Quideau, Sylvie A

    2016-01-01

    Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover) and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs) and multiple carbon-source substrate-induced respiration (MSIR) of the forest floor microbial community) environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis) showed that two above-ground (mean tree diameter, litter cover) and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs) properties were associated with variation in understory plant community composition. These results provide novel insights

  20. Understory Plant Community Composition Is Associated with Fine-Scale Above- and Below-Ground Resource Heterogeneity in Mature Lodgepole Pine (Pinus contorta) Forests

    Science.gov (United States)

    McIntosh, Anne C. S.; Macdonald, S. Ellen; Quideau, Sylvie A.

    2016-01-01

    Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these effects is critical for understanding how understory biodiversity is regulated in such forests and for anticipating impacts of changing disturbance regimes. Our primary objective was to examine the patterns of fine-scale variation in understory plant communities and their relationships to above- and below-ground resource and environmental heterogeneity within mature lodgepole pine forests. We assessed composition and diversity of understory vegetation in relation to heterogeneity of both the above-ground (canopy tree density, canopy and tall shrub basal area and cover, downed wood biomass, litter cover) and below-ground (soil nutrient availability, decomposition, forest floor thickness, pH, and phospholipid fatty acids (PLFAs) and multiple carbon-source substrate-induced respiration (MSIR) of the forest floor microbial community) environment. There was notable variation in fine-scale plant community composition; cluster and indicator species analyses of the 24 most commonly occurring understory species distinguished four assemblages, one for which a pioneer forb species had the highest cover levels, and three others that were characterized by different bryophyte species having the highest cover. Constrained ordination (distance-based redundancy analysis) showed that two above-ground (mean tree diameter, litter cover) and eight below-ground (forest floor pH, plant available boron, microbial community composition and function as indicated by MSIR and PLFAs) properties were associated with variation in understory plant community composition. These results provide novel insights

  1. Foliar uptake of fog water and transport belowground alleviates drought effects in the cloud forest tree species, Drimys brasiliensis (Winteraceae).

    Science.gov (United States)

    Eller, Cleiton B; Lima, Aline L; Oliveira, Rafael S

    2013-07-01

    Foliar water uptake (FWU) is a common water acquisition mechanism for plants inhabiting temperate fog-affected ecosystems, but the prevalence and consequences of this process for the water and carbon balance of tropical cloud forest species are unknown. We performed a series of experiments under field and glasshouse conditions using a combination of methods (sap flow, fluorescent apoplastic tracers and stable isotopes) to trace fog water movement from foliage to belowground components of Drimys brasiliensis. In addition, we measured leaf water potential, leaf gas exchange, leaf water repellency and growth of plants under contrasting soil water availabilities and fog exposure in glasshouse experiments to evaluate FWU effects on the water and carbon balance of D. brasiliensis saplings. Fog water diffused directly through leaf cuticles and contributed up to 42% of total foliar water content. FWU caused reversals in sap flow in stems and roots of up to 26% of daily maximum transpiration. Fog water transported through the xylem reached belowground pools and enhanced leaf water potential, photosynthesis, stomatal conductance and growth relative to plants sheltered from fog. Foliar uptake of fog water is an important water acquisition mechanism that can mitigate the deleterious effects of soil water deficits for D. brasiliensis. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  2. Short-Term Belowground Responses to Thinning and Burning Treatments in Southwestern Ponderosa Pine Forests of the USA

    Directory of Open Access Journals (Sweden)

    Steven T. Overby

    2016-02-01

    Full Text Available Microbial-mediated decomposition and nutrient mineralization are major drivers of forest productivity. As landscape-scale fuel reduction treatments are being implemented throughout the fire-prone western United States of America, it is important to evaluate operationally how these wildfire mitigation treatments alter belowground processes. We quantified these important belowground components before and after management-applied fuel treatments of thinning alone, thinning combined with prescribed fire, and prescribed fire in ponderosa pine (Pinus ponderosa stands at the Southwest Plateau, Fire and Fire Surrogate site, Arizona. Fuel treatments did not alter pH, total carbon and nitrogen (N concentrations, or base cations of the forest floor (O horizon or mineral soil (0–5 cm during this 2-year study. In situ rates of net N mineralization and nitrification in the surface mineral soil (0–15 cm increased 6 months after thinning with prescribed fire treatments; thinning only resulted in net N immobilization. The rates returned to pre-treatment levels after one year. Based on phospholipid fatty acid composition, microbial communities in treated areas were similar to untreated areas (control in the surface organic horizon and mineral soil (0–5 cm after treatments. Soil potential enzyme activities were not significantly altered by any of the three fuel treatments. Our results suggest that a variety of one-time alternative fuel treatments can reduce fire hazard without degrading soil fertility.

  3. Equivalence of functional limit theorems for stationary point processes and their Palm distributions

    NARCIS (Netherlands)

    Nieuwenhuis, G.

    1989-01-01

    Let P be the distribution of a stationary point process on the real line and let P0 be its Palm distribution. In this paper we consider two types of functional limit theorems, those in terms of the number of points of the point process in (0, t] and those in terms of the location of the nth point

  4. Successful range-expanding plants experience less above-ground and below-ground enemy impact.

    Science.gov (United States)

    Engelkes, Tim; Morriën, Elly; Verhoeven, Koen J F; Bezemer, T Martijn; Biere, Arjen; Harvey, Jeffrey A; McIntyre, Lauren M; Tamis, Wil L M; van der Putten, Wim H

    2008-12-18

    Many species are currently moving to higher latitudes and altitudes. However, little is known about the factors that influence the future performance of range-expanding species in their new habitats. Here we show that range-expanding plant species from a riverine area were better defended against shoot and root enemies than were related native plant species growing in the same area. We grew fifteen plant species with and without non-coevolved polyphagous locusts and cosmopolitan, polyphagous aphids. Contrary to our expectations, the locusts performed more poorly on the range-expanding plant species than on the congeneric native plant species, whereas the aphids showed no difference. The shoot herbivores reduced the biomass of the native plants more than they did that of the congeneric range expanders. Also, the range-expanding plants developed fewer pathogenic effects in their root-zone soil than did the related native species. Current predictions forecast biodiversity loss due to limitations in the ability of species to adjust to climate warming conditions in their range. Our results strongly suggest that the plants that shift ranges towards higher latitudes and altitudes may include potential invaders, as the successful range expanders may experience less control by above-ground or below-ground enemies than the natives.

  5. Processing considerations with plasma-based ion implantation of polymers: theoretical aspects, limitations, and experimental results

    International Nuclear Information System (INIS)

    Lacoste, A.; Pelletier, J.

    2003-01-01

    Processing of polymers using plasma-based ion implantation techniques (PBII) has general implications in terms of plasma specifications and pulse characteristics. In particular, the different aspects of the processing of polymer layers are discussed as functions of plasma density, pulse duration, and layer characteristics (thickness and permittivity). Clearly, severe limitations (true implantation energy, arcing) may appear for high-density plasmas as well as for long pulse durations, when processing polymer layers with thickness in the mm range. A review of the experimental results of ion implantation in polymeric materials via PBII processing is presented. The experimental results demonstrate the possibility of processing polymer layers with the PBII technique, but with severe limitations resulting from the process itself

  6. Analysis of flammability limits for the liquefaction process of oxygen-bearing coal-bed methane

    International Nuclear Information System (INIS)

    Li, Q.Y.; Wang, L.; Ju, Y.L.

    2011-01-01

    Highlights: → A novel liquefaction and distillation process is designed for oxygen bearing coal-bed methane. → Oxygen contained in coal-bed methane is removed in distillation process. → Flammability limits are analyzed for the whole operation process. → We find explosion hazard may exist in distillation tower. → Effective measures are proposed to ensure the operation safety in distillation tower. - Abstract: A novel liquefaction and distillation process has been proposed and designed for the typical oxygen-bearing coal-bed methane (CBM), in which the impurities of the oxygen and nitrogen components are removed in the distillation column. The flammability limit theory combining with HYSYS simulation results are employed to analyze and calculate the flammability limits and the results indicate that no flammability hazard exists in the stages of compression, liquefaction and throttling. However, flammability hazard exists at the top the distillation column because the methane mole fraction decreases to the value below the upper flammability limit (UFL). The safety measures of initially removing oxygen content from the feed gas combining with the control of the bottom flowrate (flowrate of the liquid product at column bottom) are proposed to ensure the operation safety of the liquefaction process. The results reveal that the operation safety of the whole process can be guaranteed, together with high methane recovery rate and high purity of the liquid product. The applicability of the liquefaction process has also been analyzed in this paper. The simulation results can offer references for the separation of oxygen from CBM, the analysis of flammability limits and the safety measures for the whole process.

  7. Gravitational Field effects on the Decoherence Process and the Quantum Speed Limit.

    Science.gov (United States)

    Dehdashti, Sh; Avazzadeh, Z; Xu, Z; Shen, J Q; Mirza, B; Wang, H

    2017-11-08

    In this paper we use spinor transformations under local Lorentz transformations to investigate the curvature effect on the quantum-to-classical transition, described in terms of the decoherence process and of the quantum speed limit. We find that gravitational fields (introduced adopting the Schwarzschild and anti-de Sitter geometries) affect both the decoherence process and the quantum speed limit of a quantum particle with spin-1/2. In addition, as a tangible example, we study the effect of the Earth's gravitational field, characterized by the Rindler space-time, on the same particle. We find that the effect of the Earth's gravitational field on the decoherence process and quantum speed limit is very small, except when the mean speed of the quantum particle is comparable to the speed of light.

  8. First Assessment of Carbon Stock in the Belowground Biomass of Brazilian Mangroves

    Directory of Open Access Journals (Sweden)

    DANIEL M.C. SANTOS

    2017-08-01

    Full Text Available ABSTRACT Studies on belowground roots biomass have increasingly reported the importance of the contribution of this compartment in carbon stock maintenance in mangrove forests. To date, there are no estimates of this contribution in Brazilian mangrove forests, although the country has the second largest area of mangroves worldwide. For this study, trenches dug in fringing forests in Guaratiba State Biological Reserve (Rio de Janeiro, Brazil were used to evaluate the contribution of the different classes of roots and the vertical stratification of carbon stock. The total carbon stock average in belowground roots biomass in these forests was 104.41 ± 20.73 tC.ha−1. From that, an average of 84.13 ± 21.34 tC.ha−1 corresponded to the carbon stock only in fine roots, which have diameters smaller than 5 mm and are responsible for over 80% of the total belowground biomass. Most of the belowground carbon stock is concentrated in the first 40 cm below the surface (about 70%. The root:shoot ratio in this study is 1.14. These estimates demonstrate that the belowground roots biomass significantly contributes, more than 50%, to the carbon stock in mangrove forests. And the mangrove root biomass can be greater than that of other Brazilian ecosystems.

  9. Plastic limit analysis with non linear kinematic strain hardening for metalworking processes applications

    International Nuclear Information System (INIS)

    Chaaba, Ali; Aboussaleh, Mohamed; Bousshine, Lahbib; Boudaia, El Hassan

    2011-01-01

    Limit analysis approaches are widely used to deal with metalworking processes analysis; however, they are applied only for perfectly plastic materials and recently for isotropic hardening ones excluding any kind of kinematic hardening. In the present work, using Implicit Standard Materials concept, sequential limit analysis approach and the finite element method, our objective consists in extending the limit analysis application for including linear and non linear kinematic strain hardenings. Because this plastic flow rule is non associative, the Implicit Standard Materials concept is adopted as a framework of non standard plasticity modeling. The sequential limit analysis procedure which considers the plastic behavior with non linear kinematic strain hardening as a succession of perfectly plastic behavior with yielding surfaces updated after each sequence of limit analysis and geometry updating is applied. Standard kinematic finite element method together with a regularization approach is used for performing two large compression cases (cold forging) in plane strain and axisymmetric conditions

  10. A global Fine-Root Ecology Database to address below-ground challenges in plant ecology.

    Science.gov (United States)

    Iversen, Colleen M; McCormack, M Luke; Powell, A Shafer; Blackwood, Christopher B; Freschet, Grégoire T; Kattge, Jens; Roumet, Catherine; Stover, Daniel B; Soudzilovskaia, Nadejda A; Valverde-Barrantes, Oscar J; van Bodegom, Peter M; Violle, Cyrille

    2017-07-01

    Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. While fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of root traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. Continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time. © 2017 UT-Battelle LLC. New Phytologist © 2017 New Phytologist Trust.

  11. Links between plant litter chemistry, species diversity, and below-ground ecosystem function.

    Science.gov (United States)

    Meier, Courtney L; Bowman, William D

    2008-12-16

    Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics of plant species diversity. We amended native soils with litter mixtures containing up to 4 alpine plant species, and we used 9 litter chemical traits to evaluate the chemical composition (i.e., the identity and quantity of compounds) and chemical diversity of the litter mixtures. The chemical composition of the litter mixtures was the strongest predictor of soil respiration, net N mineralization, and microbial biomass N. Soil respiration and net N mineralization rates were also significantly correlated with the chemical diversity of the litter mixtures. In contrast, soil C and N cycling rates were poorly correlated with plant species richness, and there was no relationship between species richness and the chemical diversity of the litter mixtures. These results indicate that the composition and diversity of chemical compounds in litter are potentially important functional traits affecting decomposition, and simple metrics like plant species richness may fail to capture variation in these traits. Litter chemical traits therefore provide a mechanistic link between organisms, species diversity, and key components of below-ground ecosystem function.

  12. Confidence limits for contribution plots in multivariate statistical process control using bootstrap estimates.

    Science.gov (United States)

    Babamoradi, Hamid; van den Berg, Frans; Rinnan, Åsmund

    2016-02-18

    In Multivariate Statistical Process Control, when a fault is expected or detected in the process, contribution plots are essential for operators and optimization engineers in identifying those process variables that were affected by or might be the cause of the fault. The traditional way of interpreting a contribution plot is to examine the largest contributing process variables as the most probable faulty ones. This might result in false readings purely due to the differences in natural variation, measurement uncertainties, etc. It is more reasonable to compare variable contributions for new process runs with historical results achieved under Normal Operating Conditions, where confidence limits for contribution plots estimated from training data are used to judge new production runs. Asymptotic methods cannot provide confidence limits for contribution plots, leaving re-sampling methods as the only option. We suggest bootstrap re-sampling to build confidence limits for all contribution plots in online PCA-based MSPC. The new strategy to estimate CLs is compared to the previously reported CLs for contribution plots. An industrial batch process dataset was used to illustrate the concepts. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Soil fertility shapes belowground food webs across a regional climate gradient.

    Science.gov (United States)

    Laliberté, Etienne; Kardol, Paul; Didham, Raphael K; Teste, François P; Turner, Benjamin L; Wardle, David A

    2017-10-01

    Changes in soil fertility during pedogenesis affect the quantity and quality of resources entering the belowground subsystem. Climate governs pedogenesis, yet how climate modulates responses of soil food webs to soil ageing remains unexplored because of the paucity of appropriate model systems. We characterised soil food webs along each of four retrogressive soil chronosequences situated across a strong regional climate gradient to show that belowground communities are predominantly shaped by changes in fertility rather than climate. Basal consumers showed hump-shaped responses to soil ageing, which were propagated to higher-order consumers. There was a shift in dominance from bacterial to fungal energy channels with increasing soil age, while the root energy channel was most important in intermediate-aged soils. Our study highlights the overarching importance of soil fertility in regulating soil food webs, and indicates that belowground food webs will respond more strongly to shifts in soil resources than climate change. © 2017 John Wiley & Sons Ltd/CNRS.

  14. Shared filtering processes link attentional and visual short-term memory capacity limits.

    Science.gov (United States)

    Bettencourt, Katherine C; Michalka, Samantha W; Somers, David C

    2011-09-30

    Both visual attention and visual short-term memory (VSTM) have been shown to have capacity limits of 4 ± 1 objects, driving the hypothesis that they share a visual processing buffer. However, these capacity limitations also show strong individual differences, making the degree to which these capacities are related unclear. Moreover, other research has suggested a distinction between attention and VSTM buffers. To explore the degree to which capacity limitations reflect the use of a shared visual processing buffer, we compared individual subject's capacities on attentional and VSTM tasks completed in the same testing session. We used a multiple object tracking (MOT) and a VSTM change detection task, with varying levels of distractors, to measure capacity. Significant correlations in capacity were not observed between the MOT and VSTM tasks when distractor filtering demands differed between the tasks. Instead, significant correlations were seen when the tasks shared spatial filtering demands. Moreover, these filtering demands impacted capacity similarly in both attention and VSTM tasks. These observations fail to support the view that visual attention and VSTM capacity limits result from a shared buffer but instead highlight the role of the resource demands of underlying processes in limiting capacity.

  15. Plant process computer replacements - techniques to limit installation schedules and costs

    International Nuclear Information System (INIS)

    Baker, M.D.; Olson, J.L.

    1992-01-01

    Plant process computer systems, a standard fixture in all nuclear power plants, are used to monitor and display important plant process parameters. Scanning thousands of field sensors and alarming out-of-limit values, these computer systems are heavily relied on by control room operators. The original nuclear steam supply system (NSSS) vendor for the power plant often supplied the plant process computer. Designed using sixties and seventies technology, a plant's original process computer has been obsolete for some time. Driven by increased maintenance costs and new US Nuclear Regulatory Commission regulations such as NUREG-0737, Suppl. 1, many utilities have replaced their process computers with more modern computer systems. Given that computer systems are by their nature prone to rapid obsolescence, this replacement cycle will likely repeat. A process computer replacement project can be a significant capital expenditure and must be performed during a scheduled refueling outage. The object of the installation process is to install a working system on schedule. Experience gained by supervising several computer replacement installations has taught lessons that, if applied, will shorten the schedule and limit the risk of costly delays. Examples illustrating this technique are given. This paper and these examples deal only with the installation process and assume that the replacement computer system has been adequately designed, and development and factory tested

  16. Multifractal properties of diffusion-limited aggregates and random multiplicative processes

    International Nuclear Information System (INIS)

    Canessa, E.

    1991-04-01

    We consider the multifractal properties of irreversible diffusion-limited aggregation (DLA) from the point of view of the self-similarity of fluctuations in random multiplicative processes. In particular we analyse the breakdown of multifractal behaviour and phase transition associated with the negative moments of the growth probabilities in DLA. (author). 20 refs, 5 figs

  17. New limit theorems for regular diffusion processes with finite speed measure

    NARCIS (Netherlands)

    J.H. van Zanten (Harry)

    2000-01-01

    textabstractWe derive limit theorems for diffusion processes that have a finite speed measure. First we prove a number of asymptotic properties of the density $rho_t = dmu_t /dmu$ of the empirical measure $mu_t$ with respect to the normalized speed measure $mu$. These results are then used to derive

  18. Short-Term Memory Limitations in Children: Capacity or Processing Deficits?

    Science.gov (United States)

    Chi, Michelene T. H.

    1976-01-01

    Evaluates the assertion that short-term memory (STM) capacity increases with age and concludes that the STM capacity limitation in children is due to the deficits in the processing strategies and speeds, which presumably improve with age through cumulative learning. (JM) Available from: Memory and Cognition, Psychonomic Society, 1018 West 34…

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-04-15

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

  20. Uniform lateral etching of tungsten in deep trenches utilizing reaction-limited NF3 plasma process

    Science.gov (United States)

    Kofuji, Naoyuki; Mori, Masahito; Nishida, Toshiaki

    2017-06-01

    The reaction-limited etching of tungsten (W) with NF3 plasma was performed in an attempt to achieve the uniform lateral etching of W in a deep trench, a capability required by manufacturing processes for three-dimensional NAND flash memory. Reaction-limited etching was found to be possible at high pressures without ion irradiation. An almost constant etching rate that showed no dependence on NF3 pressure was obtained. The effect of varying the wafer temperature was also examined. A higher wafer temperature reduced the threshold pressure for reaction-limited etching and also increased the etching rate in the reaction-limited region. Therefore, the control of the wafer temperature is crucial to controlling the etching amount by this method. We found that the uniform lateral etching of W was possible even in a deep trench where the F radical concentration was low.

  1. Welcome to the neighbourhood: interspecific genotype by genotype interactions in Solidago influence above- and belowground biomass and associated communities.

    Science.gov (United States)

    Genung, Mark A; Bailey, Joseph K; Schweitzer, Jennifer A

    2012-01-01

    Intra- and interspecific plant-plant interactions are fundamental to patterns of community assembly and to the mixture effects observed in biodiversity studies. Although much research has been conducted at the species level, very little is understood about how genetic variation within and among interacting species may drive these processes. Using clones of both Solidago altissima and Solidago gigantea, we found that genotypic variation in a plant's neighbours affected both above- and belowground plant traits, and that genotype by genotype interactions between neighbouring plants impacted associated pollinator communities. The traits for which focal plant genotypic variation explained the most variation varied by plant species, whereas neighbour genotypic variation explained the most variation in coarse root biomass. Our results provide new insight into genotypic and species diversity effects in plant-neighbour interactions, the extended consequences of diversity effects, and the potential for evolution in response to competitive or to facilitative plant-neighbour interactions. © 2011 Blackwell Publishing Ltd/CNRS.

  2. The relation between resource limitations and optional conceptual processing by children and adults.

    Science.gov (United States)

    Ackerman, B P; Spiker, K; Bailey, K

    1989-10-01

    In some situations children fail to perform optional conceptual processing that they are able to perform. The purpose of the 4 experiments was to determine if the difficulty of word identification affects optional conceptual processing by second/third graders, fifth graders, and college students in a cued recall task. Conceptual processing was manipulated by presenting Hard (e.g., hawk eagle canary) or Easy (river lake canary) word triplets that varied in the contrastive processing necessary to identify the "odd" target word (canary). The orienting activity also varied: for the Oddity Choice activity, contrastive processing was obligatory because the subject had to identify the target; for the Read activity, contrastive processing was optional because the experimenter identified the target. A recall advantage for the Hard over the Easy triplets was the measure of contrastive processing. Finally, the difficulty of word identification varied in that the subjects read the stimuli or the experimenter read the stimuli, and all the words were degraded, only the nontarget words were degraded, or all the words were intact. The results established that contrastive processing facilitates recall, and that word identification difficulty may limit the extent of optional contrastive processing.

  3. Investigation of Physical Processes Limiting Plasma Density in DIII--D

    Science.gov (United States)

    Maingi, R.

    1996-11-01

    Understanding the physical processes which limit operating density is crucial in achieving peak performance in confined plasmas. Studies from many of the world's tokamaks have indicated the existence(M. Greenwald, et al., Nucl. Fusion 28) (1988) 2199 of an operational density limit (Greenwald limit, n^GW_max) which is proportional to the plasma current and independent of heating power. Several theories have reproduced the current dependence, but the lack of a heating power dependence in the data has presented an enigma. This limit impacts the International Thermonuclear Experimental Reactor (ITER) because the nominal operating density for ITER is 1.5 × n^GW_max. In DIII-D, experiments are being conducted to understand the physical processes which limit operating density in H-mode discharges; these processes include X-point MARFE formation, high core recycling and neutral pressure, resistive MHD stability, and core radiative collapse. These processes affect plasma properties, i.e. edge/scrape-off layer conduction and radiation, edge pressure gradient and plasma current density profile, and core radiation, which in turn restrict the accessible density regime. With divertor pumping and D2 pellet fueling, core neutral pressure is reduced and X-point MARFE formation is effectively eliminated. Injection of the largest-sized pellets does cause transient formation of divertor MARFEs which occasionally migrate to the X-point, but these are rapidly extinguished in pumped discharges in the time between pellets. In contrast to Greenwald et al., it is found that the density relaxation time after pellets is largely independent of the density relative to the Greenwald limit. Fourier analysis of Mirnov oscillations indicates the de-stabilization and growth of rotating, tearing-type modes (m/n= 2/1) when the injected pellets cause large density perturbations, and these modes often reduce energy confinement back to L-mode levels. We are examining the mechanisms for de

  4. Joint preprocesser-based detector for cooperative networks with limited hardware processing capability

    KAUST Repository

    Abuzaid, Abdulrahman I.

    2015-02-01

    In this letter, a joint detector for cooperative communication networks is proposed when the destination has limited hardware processing capability. The transmitter sends its symbols with the help of L relays. As the destination has limited hardware, only U out of L signals are processed and the energy of the remaining relays is lost. To solve this problem, a joint preprocessing based detector is proposed. This joint preprocessor based detector operate on the principles of minimizing the symbol error rate (SER). For a realistic assessment, pilot symbol aided channel estimation is incorporated for this proposed detector. From our simulations, it can be observed that our proposed detector achieves the same SER performance as that of the maximum likelihood (ML) detector with all participating relays. Additionally, our detector outperforms selection combining (SC), channel shortening (CS) scheme and reduced-rank techniques when using the same U. Our proposed scheme has low computational complexity.

  5. Limit Laws and Recurrence for the Planar Lorentz Process with Infinite Horizon

    CERN Document Server

    Szász, D

    2006-01-01

    As Bleher observed the free flight vector of the planar, infinite horizon, periodic Lorentz process $\\{S_n | n=0, 1, 2, \\dots \\}$ belongs to the non-standard domain of attraction of the Gaussian law --- actually with the $\\sqrt{n \\log n}$ scaling. Our first aim is to establish his conjecture that, indeed, $\\frac{S_n}{\\sqrt{n \\log n}}$ converges in distribution to the Gaussian law (a Global Limit Theorem). Here the recent method of B\\'alint and Gou\\"ezel, \\cite{BG} helped us to essentially simplify the ideas of our earlier sketchy proof. Moreover, we can also derive a.) the local version of the Global Limit Theorem, b.) the recurrence of the planar, infinite horizon, periodic Lorentz process, and finally c.) the ergodicity of its infinite invariant measure.

  6. Impact of phosphate limitation on PHA production in a feast-famine process.

    Science.gov (United States)

    Korkakaki, Emmanouela; van Loosdrecht, Mark C M; Kleerebezem, Robbert

    2017-12-01

    Double-limitation systems have shown to induce polyhydroxyalkanoates (PHA) production in chemostat studies limited in e.g. carbon and phosphate. In this work the impact of double substrate limitation on the enrichment of a PHA producing community was studied in a sequencing batch process. Enrichments at different C/P concentration ratios in the influent were established and the effect on the PHA production capacity and the enrichment community structure was investigated. Experimental results demonstrated that when a double substrate limitation is imposed at a C/P ratio in the influent in a range of 150 (C-mol/mol), the P-content of the biomass and the specific substrate uptake rates decreased. Nonetheless, the PHA storage capacity remained high (with a maximum of 84 wt%). At a C/P ratio of 300, competition in the microbial community is based on phosphate uptake, and the PHA production capacity is lost. Biomass specific substrate uptake rates are a linear function of the cellular P-content, offering advantages for scaling-up the PHA production process due to lower oxygen requirements. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Curtailing Perovskite Processing Limitations via Lamination at the Perovskite/Perovskite Interface

    Energy Technology Data Exchange (ETDEWEB)

    Van Hest, Marinus F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Moore, David [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Klein, Talysa [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Christians, Jeffrey A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beard, Matthew C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Berry, Joseph J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dunfield, Sean P. [University of Colorado; Fabian, David M. [University of California Irvine; Dixon, Alex G. [University of Colorado; Dou, Benjia [University of Colorado; Ardo, Shane [University of California Irvine; Shaheen, Sean E. [University of Colorado

    2018-04-24

    Standard layer-by-layer solution processing methods constrain lead-halide perovskite device architectures. The layer below the perovskite must be robust to the strong organic solvents used to form the perovskite while the layer above has a limited thermal budget and must be processed in nonpolar solvents to prevent perovskite degradation. To circumvent these limitations, we developed a procedure where two transparent conductive oxide/transport material/perovskite half stacks are independently fabricated and then laminated together at the perovskite/perovskite interface. Using ultraviolet-visible absorption spectroscopy, external quantum efficiency, X-ray diffraction, and time-resolved photoluminesence spectroscopy, we show that this procedure improves photovoltaic properties of the perovskite layer. Applying this procedure, semitransparent devices employing two high-temperature oxide transport layers were fabricated, which realized an average efficiency of 9.6% (maximum: 10.6%) despite series resistance limitations from the substrate design. Overall, the developed lamination procedure curtails processing constraints, enables new device designs, and affords new opportunities for optimization.

  8. Belowground plant biomass of mountain grassland affected by regular and manipulated rainfall in 2006 and 2007

    Czech Academy of Sciences Publication Activity Database

    Fiala, Karel; Tůma, Ivan

    2008-01-01

    Roč. 1, č. 1 (2008), s. 19-22 ISSN 1803-2451 R&D Projects: GA ČR(CZ) GA526/06/0556 Institutional research plan: CEZ:AV0Z60050516 Keywords : root increments * total belowground biomass * manipulated rainfall Subject RIV: EF - Botanics

  9. Incorporating climate into belowground carbon estimates in the national greenhouse gas inventory

    Science.gov (United States)

    Matthew B. Russell; Grant M. Domke; Christopher W. Woodall; Anthony W. D’Amato

    2015-01-01

    Refined estimation of carbon (C) stocks within forest ecosystems is a critical component of efforts to reduce greenhouse gas emissions and mitigate the effects of projected climate change through forest C management. Recent evidence has pointed to the importance of climate as a driver of belowground C stocks. This study describes an approach for adjusting allometric...

  10. THE EFFECT OF OZONE ON BELOW-GROUND CARBON ALLOCATION IN WHEAT

    Science.gov (United States)

    Short term 14CO2 pulse and chase experiments were conducted in order to investigate the effect ozone on below-ground carbon allocation in spring wheat seedlings (Triticum aestivumL. ?ANZA'). Wheat seedlings were grown in a sand-hydroponic system and exposed to either high ozone ...

  11. Interactions Between a Belowground Herbivore and Primary and Secondary Root Metabolites in Wild Cabbage

    NARCIS (Netherlands)

    Van Geem, Moniek; Harvey, J.A.; Cortesero, A.M.; Raaijmakers, C.E.; Gols, R.

    2015-01-01

    Plants are attacked by both above- and belowground herbivores. Toxic secondary compounds are part of the chemical defense arsenal of plants against a range of antagonists, and are subject to genetic variation. Plants also produce primary metabolites (amino acids, nutrients, sugars) that function as

  12. Plant-Mediated Systemic Interactions Between Pathogens, Parasitic Nematodes, and Herbivores Above- and Belowground

    NARCIS (Netherlands)

    Biere, A.; Goverse, A.

    2016-01-01

    Plants are important mediators of interactions between aboveground (AG) and belowground (BG) pathogens, arthropod herbivores, and nematodes (phytophages). We highlight recent progress in our understanding of within- and cross-compartment plant responses to these groups of phytophages in terms of

  13. Plant-mediated systemic interactions between pathogens, parasitic nematodes, and herbivores above- and belowground

    NARCIS (Netherlands)

    Biere, A.; Goverse, Aska

    2016-01-01

    Plants are important mediators of interactions between aboveground (AG) and belowground (BG) pathogens, arthropod herbivores, and nematodes (phytophages). We highlight recent progress in our understanding of within and cross-compartment plant responses to these groups of phytophages in terms of

  14. Stimulation of the Salicylic Acid Pathway Aboveground Recruits Entomopathogenic Nematodes Belowground.

    Directory of Open Access Journals (Sweden)

    Camila Cramer Filgueiras

    Full Text Available Plant defense pathways play a critical role in mediating tritrophic interactions between plants, herbivores, and natural enemies. While the impact of plant defense pathway stimulation on natural enemies has been extensively explored aboveground, belowground ramifications of plant defense pathway stimulation are equally important in regulating subterranean pests and still require more attention. Here we investigate the effect of aboveground stimulation of the salicylic acid pathway through foliar application of the elicitor methyl salicylate on belowground recruitment of the entomopathogenic nematode, Steinernema diaprepesi. Also, we implicate a specific root-derived volatile that attracts S. diaprepesi belowground following aboveground plant stimulation by an elicitor. In four-choice olfactometer assays, citrus plants treated with foliar applications of methyl salicylate recruited S. diaprepesi in the absence of weevil feeding as compared with negative controls. Additionally, analysis of root volatile profiles of citrus plants receiving foliar application of methyl salicylate revealed production of d-limonene, which was absent in negative controls. The entomopathogenic nematode S. diaprepesi was recruited to d-limonene in two-choice olfactometer trials. These results reinforce the critical role of plant defense pathways in mediating tritrophic interactions, suggest a broad role for plant defense pathway signaling belowground, and hint at sophisticated plant responses to pest complexes.

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

    Science.gov (United States)

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

    2009-01-01

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

  16. Root herbivory indirectly affects above- and below-ground community members and directly reduces plant performance

    NARCIS (Netherlands)

    Barber, N.A.; Milano, N.J.; Kiers, E.T.; Theis, N.; Bartolo, V.; Hazzard, R.V.; Adler, L.S.

    2015-01-01

    There is a widespread recognition that above- and below-ground organisms are linked through their interactions with host plants that span terrestrial subsystems. In addition to direct effects on plants, soil organisms such as root herbivores can indirectly alter interactions between plants and other

  17. Mechanisms and ecological implications of plant-mediated interactions between belowground and aboveground insect herbivores

    NARCIS (Netherlands)

    Papadopoulou, G.V.; Dam, N.M. van

    2017-01-01

    Plant-mediated interactions between belowground (BG) and aboveground (AG) herbivores have received increasing interest recently. However, the molecular mechanisms underlying ecological consequences of BG–AG interactions are not fully clear yet. Herbivore-induced plant defenses are complex and

  18. Interactive effects of above- and belowground herbivory and plant competition on plant growth and defence

    NARCIS (Netherlands)

    Jing, Y.; Raaijmakers, C.; Kostenko, O.; Kos, M.; Mulder, P.P.J.; Bezemer, T.M.

    2015-01-01

    Competition and herbivory are two major factors that can influence plant growth and plant defence. Although these two factors are often studied separately, they do not operate independently. We examined how aboveground herbivory by beet armyworm larvae (Spodoptera exigua) and belowground herbivory

  19. Root interactions in a diverse grassland : the role of root traits in belowground productivity and decomposition

    NARCIS (Netherlands)

    Oram, Natalie J.

    2018-01-01

    Background Plant diversity influences ecosystem functioning. A positive relation between plant diversity and productivity above- and belowground has been established. Aboveground, this effect has been shown to be due to complementarity effects, interactions between species in a mixture

  20. Stimulation of the Salicylic Acid Pathway Aboveground Recruits Entomopathogenic Nematodes Belowground

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S.; Junior, Alcides Moino; Pareja, Martin; Borai, Fahiem El; Dickson, Donald W.; Stelinski, Lukasz L.; Duncan, Larry W.

    2016-01-01

    Plant defense pathways play a critical role in mediating tritrophic interactions between plants, herbivores, and natural enemies. While the impact of plant defense pathway stimulation on natural enemies has been extensively explored aboveground, belowground ramifications of plant defense pathway stimulation are equally important in regulating subterranean pests and still require more attention. Here we investigate the effect of aboveground stimulation of the salicylic acid pathway through foliar application of the elicitor methyl salicylate on belowground recruitment of the entomopathogenic nematode, Steinernema diaprepesi. Also, we implicate a specific root-derived volatile that attracts S. diaprepesi belowground following aboveground plant stimulation by an elicitor. In four-choice olfactometer assays, citrus plants treated with foliar applications of methyl salicylate recruited S. diaprepesi in the absence of weevil feeding as compared with negative controls. Additionally, analysis of root volatile profiles of citrus plants receiving foliar application of methyl salicylate revealed production of d-limonene, which was absent in negative controls. The entomopathogenic nematode S. diaprepesi was recruited to d-limonene in two-choice olfactometer trials. These results reinforce the critical role of plant defense pathways in mediating tritrophic interactions, suggest a broad role for plant defense pathway signaling belowground, and hint at sophisticated plant responses to pest complexes. PMID:27136916

  1. Comparison of heterotrophic and autotrophic denitrification processes for nitrate removal from phosphorus-limited surface water.

    Science.gov (United States)

    Wang, Zheng; He, Shengbing; Huang, Jungchen; Zhou, Weili; Chen, Wanning

    2018-03-29

    Phosphorus (P) limitation has been demonstrated for micro-polluted surface water denitrification treatment in previous study. In this paper, a lab-scale comparative study of autotrophic denitrification (ADN) and heterotrophic denitrification (HDN) in phosphorus-limited surface water was investigated, aiming to find out the optimal nitrogen/phosphorus (N/P) ratio and the mechanism of the effect of P limitation on ADN and HDN. Furthermore, the optimal denitrification process was applied to the West Lake denitrification project, aiming to improve the water quality of the West Lake from worse than grade V to grade IV (GB3838-2006). The lab-scale study showed that the lack of P indeed inhibited HDN more greatly than ADN. The optimal N/P ratio for ADN and HDN was 25 and a 0.15 mg PO 4 3- -P L -1 of microbial available phosphorus (MAP) was observed. P additions could greatly enhance the resistance of ADN and HDN to hydraulic loading shock. Besides, The P addition could effectively stimulate the HDN performance via enriching the heterotrophic denitrifiers and the denitrifying phosphate-accumulating organisms (DNPAOs). Additionally, HDN was more effective and cost-effective than ADN for treating P-limited surface water. The study of the full-scale HDBF (heterotrophic denitrification biofilter) indicated that the denitrification performance was periodically impacted by P limitation, particularly at low water temperatures. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Belowground Carbon Allocation and Plant-Microbial Interactions Drive Resistance and Resilience of Mountain Grassland Communities to Drought

    Science.gov (United States)

    Karlowsky, S.; Augusti, A.; Ingrisch, J.; Hasibeder, R.; Lavorel, S.; Bahn, M.; Gleixner, G.

    2016-12-01

    Belowground carbon allocation (BCA) and plant-microbial interactions are crucial for the functioning of terrestrial ecosystems. Recent research suggests that extreme events can have severe effects on these processes but it is unknown how land use intensity potentially modifies their responses. We studied the resistance and resilience of mountain grassland communities to prolonged drought and investigated the role of plant C allocation and soil microbial communities in mediating drought resistance and immediate recovery. In a common garden experiment we exposed monoliths from an abandoned grassland and a hay meadow to an early summer drought. Two independent 13C pulse labeling experiments were conducted, the first during peak drought and the second during the recovery phase. The 13C incorporation was analyzed in above- and belowground plant parts and in phospho- and neutral lipid fatty acids of soil microorganisms. In addition, a 15N label was added at the rewetting to determine plant N uptake. We found that C uptake, BCA and C transfer to soil microorganisms were less strongly reduced by drought in the abandoned grassland than in the meadow. Moreover, drought induced an increase of arbuscular mycorrhiza fungi (AMF) marker in the abandoned grassland. Nevertheless, C uptake and related parameters were quickly recovered and N uptake increased in the meadow during recovery. Unexpectedly, AMF and their C uptake were generally reduced during recovery, while bacteria increased and quickly recovered C uptake, particularly in the meadow. Our results showed a negative relation between high resistance and fast recovery. The more resistant abandoned grassland plant communities seemed to invest more C below ground and into interactions with AMF during drought, likely to access water through their hyphal network. Conversely, meadow communities invested more C from recent photosynthesis into bacterial communities during recovery, obviously to gain more nutrients for regrowth

  3. Long-term variation in above and belowground plant inputs alters soil organic matter biogeochemistry at the molecular-level

    Science.gov (United States)

    Simpson, M. J.; Pisani, O.; Lin, L.; Lun, O.; Simpson, A.; Lajtha, K.; Nadelhoffer, K. J.

    2015-12-01

    The long-term fate of soil carbon reserves with global environmental change remains uncertain. Shifts in moisture, altered nutrient cycles, species composition, or rising temperatures may alter the proportions of above and belowground biomass entering soil. However, it is unclear how long-term changes in plant inputs may alter the composition of soil organic matter (SOM) and soil carbon storage. Advanced molecular techniques were used to assess SOM composition in mineral soil horizons (0-10 cm) after 20 years of Detrital Input and Removal Treatment (DIRT) at the Harvard Forest. SOM biomarkers (solvent extraction, base hydrolysis and cupric (II) oxide oxidation) and both solid-state and solution-state nuclear magnetic resonance (NMR) spectroscopy were used to identify changes in SOM composition and stage of degradation. Microbial activity and community composition were assessed using phospholipid fatty acid (PLFA) analysis. Doubling aboveground litter inputs decreased soil carbon content, increased the degradation of labile SOM and enhanced the sequestration of aliphatic compounds in soil. The exclusion of belowground inputs (No roots and No inputs) resulted in a decrease in root-derived components and enhanced the degradation of leaf-derived aliphatic structures (cutin). Cutin-derived SOM has been hypothesized to be recalcitrant but our results show that even this complex biopolymer is susceptible to degradation when inputs entering soil are altered. The PLFA data indicate that changes in soil microbial community structure favored the accelerated processing of specific SOM components with littler manipulation. These results collectively reveal that the quantity and quality of plant litter inputs alters the molecular-level composition of SOM and in some cases, enhances the degradation of recalcitrant SOM. Our study also suggests that increased litterfall is unlikely to enhance soil carbon storage over the long-term in temperate forests.

  4. Adopted levels and derived limits for Ra-226 and the decision making processes concerning TENORM releases

    International Nuclear Information System (INIS)

    Paschoa, A.S.

    2002-01-01

    A fraction of a primary dose limit can be, in general, agreed upon as a dose related level to be adopted in decision-making processes. In the case of TENORM releases, fractions of primary dose levels for 226 Ra, 228 Ra, and 210 Po may be of particular importance to establish adopted levels and derived limits to guide decision making processes. Thus, for example, a registration level for 226 Ra could be adopted at the highest portion of the natural background variation. Above such level, intervention and remedial action levels could also be adopted. All those levels would be fractions of the primary level, but translated in terms of derived limits expressed in practical units. Derived limits would then be calculated by using environmental models. In such approach 'critical groups' would have to be carefully defined and identified. In addition, the size of a critical group would be chosen to be used in environmental modeling. Site specific environmental models and parameters are desirable, though unavailable, or very difficult to obtain, in most cases. Thus, mathematical models and parameters of more generic nature are often used. A sensitive parametric analysis can make a ranking of the parameters used in a model, allowing one to choose how important each parameter will be for the model output. The paper will point out that when using the adopted levels and derived limits, as suggested above, the uncertainties and importance of the parameters entering an environmental model can make the difference for decision makers to take the right or wrong decision, as far as radiological protection is concerned. (author)

  5. The roots of defense: plant resistance and tolerance to belowground herbivory.

    Directory of Open Access Journals (Sweden)

    Sean M Watts

    2011-04-01

    Full Text Available There is conclusive evidence that there are fitness costs of plant defense and that herbivores can drive selection for defense. However, most work has focused on above-ground interactions, even though belowground herbivory may have greater impacts on individual plants than above-ground herbivory. Given the role of belowground plant structures in resource acquisition and storage, research on belowground herbivores has much to contribute to theories on the evolution of plant defense. Pocket gophers (Geomyidae provide an excellent opportunity to study root herbivory. These subterranean rodents spend their entire lives belowground and specialize on consuming belowground plant parts.We compared the root defenses of native forbs from mainland populations (with a history of gopher herbivory to island populations (free from gophers for up to 500,000 years. Defense includes both resistance against herbivores and tolerance of herbivore damage. We used three approaches to compare these traits in island and mainland populations of two native California forbs: 1 Eschscholzia californica populations were assayed to compare alkaloid deterrents, 2 captive gophers were used to test the palatability of E. californica roots and 3 simulated root herbivory assessed tolerance to root damage in Deinandra fasciculata and E. californica. Mainland forms of E. californica contained 2.5 times greater concentration of alkaloids and were less palatable to gophers than island forms. Mainland forms of D. fasciculata and, to a lesser extent, E. californica were also more tolerant of root damage than island conspecifics. Interestingly, undamaged island individuals of D. fasciculata produced significantly more fruit than either damaged or undamaged mainland individuals.These results suggest that mainland plants are effective at deterring and tolerating pocket gopher herbivory. Results also suggest that both forms of defense are costly to fitness and thus reduced in the absence of

  6. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids.

    Science.gov (United States)

    Singh, Akanksha; Braun, Julia; Decker, Emilia; Hans, Sarah; Wagner, Agnes; Weisser, Wolfgang W; Zytynska, Sharon E

    2014-10-21

    Interactions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations. Our data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass. Previous work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved.

  7. Adopted levels and derived limits for Ra-226 and the decision making processes concerning TENORM releases

    International Nuclear Information System (INIS)

    Paschoa, A.S.

    2002-01-01

    A fraction of a primary dose limit can be, in general, agreed upon as a dose related level to be adopted in decision-making processes. In the case of TENORM releases, fractions of primary dose levels for 226 Ra, 228 Ra, and 210 Po may be of particular importance to establish adopted levels for 226 Ra could be adopted at the highest portion of the natural background variation. Above such level, intervention and remedial action levels could also be adopted. All those levels would be fractions of the primary level, but translated in terms of derived limits expressed in practical units. Derived limits would then be calculated by using environmental models. In such approach 'critical groups' would have to be carefully defined and identified. In addition, the size of a critical group would be chosen to be used in environmental modeling. Site specific environmental models and parameters are desirable, though unavailable, or very difficult to obtain, in most cases. Thus, mathematical models and parameters of more generic nature are often used. A sensitive parametric analysis can make a ranking of the parameters used in a model, allowing one to choose how important each parameter will be for the model output. The paper will point out that when using the adopted levels and derived limits, as suggested above, the uncertainties and importance of the parameters entering an environmental model can make the difference for decision makers to take the right or wrong decision, as far as radiological protection is concerned. (author)

  8. Modeling intermediate product selection under production and storage capacity limitations in food processing

    DEFF Research Database (Denmark)

    Kilic, Onur Alper; Akkerman, Renzo; Grunow, Martin

    2009-01-01

    In the food industry products are usually characterized by their recipes, which are specified by various quality attributes. For end products, this is given by customer requirements, but for intermediate products, the recipes can be chosen in such a way that raw material procurement costs and pro...... with production and inventory planning, thereby considering the production and storage capacity limitations. The resulting model can be used to solve an important practical problem typical for many food processing industries.......In the food industry products are usually characterized by their recipes, which are specified by various quality attributes. For end products, this is given by customer requirements, but for intermediate products, the recipes can be chosen in such a way that raw material procurement costs...... and processing costs are minimized. However, this product selection process is bound by production and storage capacity limitations, such as the number and size of storage tanks or silos. In this paper, we present a mathematical programming approach that combines decision making on product selection...

  9. Anaerobic digestion of slaughterhouse waste: main process limitations and microbial community interactions.

    Science.gov (United States)

    Palatsi, J; Viñas, M; Guivernau, M; Fernandez, B; Flotats, X

    2011-02-01

    Fresh pig/cattle slaughterhouse waste mixtures, with different lipid-protein ratios, were characterized and their anaerobic biodegradability assessed in batch tests. The resultant methane potentials were high (270-300 L(CH4) kg(-1)(COD)) making them interesting substrates for the anaerobic digestion process. However, when increasing substrate concentrations in consecutive batch tests, up to 15 g(COD) kg(-1), a clear inhibitory process was monitored. Despite the reported severe inhibition, related to lipid content, the system was able to recover activity and successfully degrade the substrate. Furthermore, 16SrRNA gene-based DGGE results showed an enrichment of specialized microbial populations, such as β-oxidizing/proteolitic bacteria (Syntrophomonas sp., Coprothermobacter sp. and Anaerobaculum sp.), and syntrophic methanogens (Methanosarcina sp.). Consequently, the lipid concentration of substrate and the structure of the microbial community are the main limiting factors for a successful anaerobic treatment of fresh slaughterhouse waste. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Jarosite formation in the uranium processing circuit of Denison Mines Limited, Elliot Lake, Ontario

    International Nuclear Information System (INIS)

    Dutrizac, J.E.

    1985-04-01

    Jarosite precipitation occurs in several parts of the uranium processing circuit of Denison Mines Limited, Elliot Lake, Ontario. Extensive precipitation of jarosite takes place in the filter cloth and on the drum face of the secondary drum filters, and this precipitation causes severe operating difficulties. Precipitation of jarosite is also observed in the ion exchange beads, but it is not known whether the jarosite is responsible for the observed decrease in resin efficiency. The resin beads are also rimmed with significant quantities of silica, lead, phosphate, sulphate, etc. which could be responsible for the fouling of the resin. In every instance, potassium jarosite, containing only minor amounts of sodium or ammonium, was the observed species; the potassium likely originates from the acid leaching of muscovite in the ore. Potential methods of avoiding the jarosite problem are discussed, but these may not be compatible with the overall process requirements

  11. Limited ability driven phase transitions in the coevolution process in Axelrod's model

    Science.gov (United States)

    Wang, Bing; Han, Yuexing; Chen, Luonan; Aihara, Kazuyuki

    2009-04-01

    We study the coevolution process in Axelrod's model by taking into account of agents' abilities to access information, which is described by a parameter α to control the geographical range of communication. We observe two kinds of phase transitions in both cultural domains and network fragments, which depend on the parameter α. By simulation, we find that not all rewiring processes pervade the dissemination of culture, that is, a very limited ability to access information constrains the cultural dissemination, while an exceptional ability to access information aids the dissemination of culture. Furthermore, by analyzing the network characteristics at the frozen states, we find that there exists a stage at which the network develops to be a small-world network with community structures.

  12. Limited ability driven phase transitions in the coevolution process in Axelrod's model

    Energy Technology Data Exchange (ETDEWEB)

    Wang Bing [ERATO Aihara Complexity Modelling Project, JST, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Institute of Industrial Science, University of Tokyo, Tokyo (Japan)], E-mail: bingbignmath@gmail.com; Han Yuexing [Graduate School of Information System, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu-Shi, Tokyo (Japan); Chen Luonan [Department of Electrical Engineering and Electronics, Osaka Sangyo University, Daito, Osaka 574-8530 (Japan); Aihara, Kazuyuki [ERATO Aihara Complexity Modelling Project, JST, Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Institute of Industrial Science, University of Tokyo, Tokyo (Japan)

    2009-04-13

    We study the coevolution process in Axelrod's model by taking into account of agents' abilities to access information, which is described by a parameter {alpha} to control the geographical range of communication. We observe two kinds of phase transitions in both cultural domains and network fragments, which depend on the parameter {alpha}. By simulation, we find that not all rewiring processes pervade the dissemination of culture, that is, a very limited ability to access information constrains the cultural dissemination, while an exceptional ability to access information aids the dissemination of culture. Furthermore, by analyzing the network characteristics at the frozen states, we find that there exists a stage at which the network develops to be a small-world network with community structures.

  13. Anomalous scaling due to correlations: limit theorems and self-similar processes

    International Nuclear Information System (INIS)

    Stella, Attilio L; Baldovin, Fulvio

    2010-01-01

    We derive theorems which outline explicit mechanisms by which anomalous scaling for the probability density function of the sum of many correlated random variables asymptotically prevails. The results characterize general anomalous scaling forms, explain their universal character, and specify universality domains in the spaces of joint probability density functions of the summand variables. These density functions are assumed to be invariant under arbitrary permutations of their arguments. Examples from the theory of critical phenomena are discussed. The novel notion of stability implied by the limit theorems also allows us to define sequences of random variables whose sum satisfies anomalous scaling for any finite number of summands. If regarded as developing in time, the stochastic processes described by these variables are non-Markovian generalizations of Gaussian processes with uncorrelated increments, and provide, e.g., explicit realizations of a recently proposed model of index evolution in finance

  14. Sensory shelf-life limiting factor of high hydrostatic pressure processed avocado paste.

    Science.gov (United States)

    Jacobo-Velázquez, D A; Hernández-Brenes, C

    2011-08-01

    High hydrostatic pressure (HHP) processing pasteurizes avocado paste without a significant impact on flavor. Although HHP-treated avocado paste stored under refrigeration is safe for human consumption for months, sensory changes taking place during storage cause the rejection of the product by consumers within days. Although it is known that the shelf life of the product ends before its microbial counts are high, its sensory shelf life limiting factor remains unknown. The present study focused on the use of a trained panel and a consumer panel to determine the sensory shelf life limiting factor of HHP-treated avocado paste. The trained panel identified sour and rancid flavors as the main sensory descriptors (critical descriptors) that differentiated stored from freshly processed samples. Further data obtained from consumers identified sour flavor as the main cause for a significant decrease in the acceptability (shelf life limiting factor) of refrigerated HHP-treated avocado paste. The study allowed the elucidation of a proposed deterioration mechanism for HHP-treated avocado paste during its refrigerated shelf life. The information through this work enhances scientific knowledge of the product and proposes the sour flavor development during storage as a relevant sensory attribute that needs to be improved in order to enhance the product shelf life. At present, HHP is the most effective commercial nonthermal technology to process avocado paste when compared to thermal and chemical alternatives. HHP-treated avocado paste is a microbiologically stable food for a period of at least 45 d stored under refrigeration. However, previous published work indicated that consumers rejected the product after approximately 19 d of storage due to sensory changes. This manuscript presents a sensory study that permitted the identification of the critical sensory descriptor that is acting as the sensory shelf life limiting factor of the product. The data presented herein along with

  15. Averaging, not internal noise, limits the development of coherent motion processing

    Directory of Open Access Journals (Sweden)

    Catherine Manning

    2014-10-01

    Full Text Available The development of motion processing is a critical part of visual development, allowing children to interact with moving objects and navigate within a dynamic environment. However, global motion processing, which requires pooling motion information across space, develops late, reaching adult-like levels only by mid-to-late childhood. The reasons underlying this protracted development are not yet fully understood. In this study, we sought to determine whether the development of motion coherence sensitivity is limited by internal noise (i.e., imprecision in estimating the directions of individual elements and/or global pooling across local estimates. To this end, we presented equivalent noise direction discrimination tasks and motion coherence tasks at both slow (1.5°/s and fast (6°/s speeds to children aged 5, 7, 9 and 11 years, and adults. We show that, as children get older, their levels of internal noise reduce, and they are able to average across more local motion estimates. Regression analyses indicated, however, that age-related improvements in coherent motion perception are driven solely by improvements in averaging and not by reductions in internal noise. Our results suggest that the development of coherent motion sensitivity is primarily limited by developmental changes within brain regions involved in integrating motion signals (e.g., MT/V5.

  16. Limitations of turbidity process probes and formazine as their calibration standard.

    Science.gov (United States)

    Münzberg, Marvin; Hass, Roland; Dinh Duc Khanh, Ninh; Reich, Oliver

    2017-01-01

    Turbidity measurements are frequently implemented for the monitoring of heterogeneous chemical, physical, or biotechnological processes. However, for quantitative measurements, turbidity probes need calibration, as is requested and regulated by the ISO 7027:1999. Accordingly, a formazine suspension has to be produced. Despite this regulatory demand, no scientific publication on the stability and reproducibility of this polymerization process is available. In addition, no characterization of the optical properties of this calibration material with other optical methods had been achieved so far. Thus, in this contribution, process conditions such as temperature and concentration have been systematically investigated by turbidity probe measurements and Photon Density Wave (PDW) spectroscopy, revealing an influence on the temporal formazine formation onset. In contrast, different reaction temperatures do not lead to different scattering properties for the final formazine suspensions, but give an access to the activation energy for this condensation reaction. Based on PDW spectroscopy data, the synthesis of formazine is reproducible. However, very strong influences of the ambient conditions on the measurements of the turbidity probe have been observed, limiting its applicability. The restrictions of the turbidity probe with respect to scatterer concentration are examined on the basis of formazine and polystyrene suspensions. Compared to PDW spectroscopy data, signal saturation is observed at already low reduced scattering coefficients.

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

    OpenAIRE

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

    2013-01-01

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

  18. Water and Nitrogen Limitations of Ecosystem Processes Across Three Dryland Plant Communities

    Science.gov (United States)

    Beltz, C.; Lauenroth, W. K.; Burke, I. C.

    2017-12-01

    The availability of water and nitrogen (N) play a major role in controlling the distribution of ecosystem types and the rates of ecosystem processes across the globe. Both these resources are being altered by human activity. Anthropogenic fixation of N has increased inputs into the biosphere from 0.5 kg N ha-1 yr-1 to upwards of 10 kg N ha-1 yr-1, while the amount and seasonality of precipitation are expected to continue to change. Within dryland environments, the relationships between increasingly available N and ecosystem processes are especially complex due to dryland's characteristic strong limitation by low and highly variable precipitation. Other experiments have shown that this interplay between N and water can cause temporally complex co-limitation and spatially complex responses with variable effects on ecosystems, such as those to net primary productivity, soil respiration, and plant community composition. Research spanning multiple dryland plant communities is critical for generalizing findings to the 40% of the Earth's terrestrial surface covered in dryland ecosystems. Given IPCC projections in which both N availability and precipitation are altered, examining their interactive effect across multiple plant communities is critical to increasing our understanding of the limitations to ecosystem process in drylands. We are studying a gradient of three plant communities representing a C4 grassland (shortgrass steppe), a C3/C4 grassland (mixed grass prairie), and a shrub-dominated ecosystem with C3 and C4 grasses (sagebrush steppe). We added two levels of N (10 kg N ha-1 and 100 kg N ha-1) and increased summer monthly precipitation by 20%. Sites responded differently to treatments, with the scale of effect varying by treatment. The high-level nitrogen increased soil N availability and soil respiration, while decreasing soil carbon in the labile pool in the upper soil layers. These results will allow for better understanding of increased N in combination with

  19. A below-ground herbivore shapes root defensive chemistry in natural plant populations

    OpenAIRE

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Th?o; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root ...

  20. Stochastic Dynamics of Discrete Curves and Exclusion Processes. Part 1: Hydrodynamic Limit of the ASEP System

    CERN Document Server

    Fayolle, G; Fayolle, Guy; Furtlehner, Cyril

    2006-01-01

    This report is the foreword of a series of stochastic deformations of curves. Problems are set in terms of exclusion processes, the ultimate goal being to derive hydrodynamic limits for these systems after proper scalings. In this study, solely the basic texts system on the torus is analyzed. The usual sequence of empirical measures, converges in probability to a deterministic measure, which is the unique weak solution of a Cauchy problem. The method presents some new features, letting hope for extensions to higher dimension. It relies on the analysis of a family of parabolic differential operators, involving variational calculus. Namely, the variables are the values of functions at given points, their number being possibly infinite.

  1. Limitations Of The Current State Space Modelling Approach In Multistage Machining Processes Due To Operation Variations

    Science.gov (United States)

    Abellán-Nebot, J. V.; Liu, J.; Romero, F.

    2009-11-01

    The State Space modelling approach has been recently proposed as an engineering-driven technique for part quality prediction in Multistage Machining Processes (MMP). Current State Space models incorporate fixture and datum variations in the multi-stage variation propagation, without explicitly considering common operation variations such as machine-tool thermal distortions, cutting-tool wear, cutting-tool deflections, etc. This paper shows the limitations of the current State Space model through an experimental case study where the effect of the spindle thermal expansion, cutting-tool flank wear and locator errors are introduced. The paper also discusses the extension of the current State Space model to include operation variations and its potential benefits.

  2. Strategies to reduce mass and photons transfer limitations in heterogeneous photocatalytic processes: Hexavalent chromium reduction studies.

    Science.gov (United States)

    Marinho, Belisa A; Cristóvão, Raquel O; Djellabi, Ridha; Caseiro, Ana; Miranda, Sandra M; Loureiro, José M; Boaventura, Rui A R; Dias, Madalena M; Lopes, José Carlos B; Vilar, Vítor J P

    2018-07-01

    The current work presents different approaches to overcome mass and photon transfer limitations in heterogeneous photocatalytic processes applied to the reduction of hexavalent chromium to its trivalent form in the presence of a sacrificial agent. Two reactor designs were tested, a monolithic tubular photoreactor (MTP) and a micro-meso-structured photoreactor (NETmix), both presenting a high catalyst surface area per reaction liquid volume. In order to reduce photon transfer limitations, the tubular photoreactor was packed with transparent cellulose acetate monolithic structures (CAM) coated with the catalyst by a dip-coating method. For the NETmix reactor, a thin film of photocatalyst was uniformly deposited on the front glass slab (GS) or on the network of channels and chambers imprinted in the back stainless steel slab (SSS) using a spray system. The reaction rate for the NETmix photoreactor was evaluated for two illumination sources, solar light or UVA-LEDs, using the NETmix with the front glass slab or/and back stainless steel slab coated with TiO 2 -P25. The reusability of the photocatalytic films on the NETmix walls was also evaluated for three consecutive cycles using fresh Cr(VI) solutions. The catalyst reactivity in combination with the NETmix-SSS photoreactor is almost 70 times superior to one obtained with the MTP. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Experimental quantum key distribution with simulated ground-to-satellite photon losses and processing limitations

    Science.gov (United States)

    Bourgoin, Jean-Philippe; Gigov, Nikolay; Higgins, Brendon L.; Yan, Zhizhong; Meyer-Scott, Evan; Khandani, Amir K.; Lütkenhaus, Norbert; Jennewein, Thomas

    2015-11-01

    Quantum key distribution (QKD) has the potential to improve communications security by offering cryptographic keys whose security relies on the fundamental properties of quantum physics. The use of a trusted quantum receiver on an orbiting satellite is the most practical near-term solution to the challenge of achieving long-distance (global-scale) QKD, currently limited to a few hundred kilometers on the ground. This scenario presents unique challenges, such as high photon losses and restricted classical data transmission and processing power due to the limitations of a typical satellite platform. Here we demonstrate the feasibility of such a system by implementing a QKD protocol, with optical transmission and full post-processing, in the high-loss regime using minimized computing hardware at the receiver. Employing weak coherent pulses with decoy states, we demonstrate the production of secure key bits at up to 56.5 dB of photon loss. We further illustrate the feasibility of a satellite uplink by generating a secure key while experimentally emulating the varying losses predicted for realistic low-Earth-orbit satellite passes at 600 km altitude. With a 76 MHz source and including finite-size analysis, we extract 3374 bits of a secure key from the best pass. We also illustrate the potential benefit of combining multiple passes together: while one suboptimal "upper-quartile" pass produces no finite-sized key with our source, the combination of three such passes allows us to extract 165 bits of a secure key. Alternatively, we find that by increasing the signal rate to 300 MHz it would be possible to extract 21 570 bits of a secure finite-sized key in just a single upper-quartile pass.

  4. Youth researching youth: benefits, limitations and ethical considerations within a participatory research process

    Directory of Open Access Journals (Sweden)

    Cynthia G. Jardine

    2012-05-01

    Full Text Available Objectives. To examine the benefits, limitations and ethical issues associated with conducting participatory research on tobacco use using youth to research other youth. Study design. Community-based participatory research. Methods. Research on tobacco use was conducted with students in the K’àlemì Dene School and Kaw Tay Whee School in the Northwest Territories, Canada, using PhotoVoice. The Grade 9–12 students acted as researchers. Researcher reflections and observations were assessed using “member checking,” whereby students, teachers and community partners could agree or disagree with the researcher's interpretation. The students and teachers were further asked informally to share their own reflections and observations on this process. Results and conclusions. Using youth to research other youth within a participatory research framework had many benefits for the quality of the research, the youth researchers and the community. The research was perceived by the researchers and participants to be more valid and credible. The approach was more appropriate for the students, and the youth researchers gained valuable research experience and a sense of ownership of both the research process and results. Viewing smoking through their children's eyes was seen by the community to be a powerful and effective means of creating awareness of the community environment. Limitations of the approach were residual response bias of participants, the short period of time to conduct the research and failure to fully explore student motivations to smoke or not to smoke. Ethical considerations included conducting research with minors, difficulties in obtaining written parental consent, decisions on cameras (disposable versus digital and representation of all participants in the final research product.

  5. POLICY FRAMEWORK FOR UTILIZATION AND CONSERVATION OF BELOW-GROUND BIODIVERSITY IN KENYA

    Directory of Open Access Journals (Sweden)

    Celline Achieng

    2009-10-01

    Full Text Available The reasons for the lack of inclusion of below-ground biodiversity in the Kenyan policy and legal framework were sought. Gaps were identified in the relevant sectoral policies and laws in regard to the domestication of the Convention on Biological Diversity (CBD. Below -ground biodiversity had no specific schedule in any of the sectoral laws. Most sectoral laws were particular about the larger biodiversity and soils but had no mention of below-ground biodiversity. Material Transfer Agreements and Material Acquisition Agreements that are regarded as tools of domestication of the CBD to guide transfers, exchanges and acquisition of soil organisms lacked a regulating policy. The lack of regulating policy could be attributed to the delay in approval of draft regulations by the Ministry of Environment while the lack of inclusion of below-ground biodiversity in Kenya’s legal and policy framework could be as a result of lack of awareness and appreciation among stakeholders.

  6. Belowground legacies of Pinus contorta invasion and removal result in multiple mechanisms of invasional meltdown.

    Science.gov (United States)

    Dickie, Ian A; St John, Mark G; Yeates, Gregor W; Morse, Chris W; Bonner, Karen I; Orwin, Kate; Peltzer, Duane A

    2014-01-01

    Plant invasions can change soil biota and nutrients in ways that drive subsequent plant communities, particularly when co-invading with belowground mutualists such as ectomycorrhizal fungi. These effects can persist following removal of the invasive plant and, combined with effects of removal per se, influence subsequent plant communities and ecosystem functioning. We used field observations and a soil bioassay with multiple plant species to determine the belowground effects and post-removal legacy caused by invasion of the non-native tree Pinus contorta into a native plant community. Pinus facilitated ectomycorrhizal infection of the co-occurring invasive tree, Pseudotsuga menziesii, but not conspecific Pinus (which always had ectomycorrhizas) nor the native pioneer Kunzea ericoides (which never had ectomycorrhizas). Pinus also caused a major shift in soil nutrient cycling as indicated by increased bacterial dominance, NO3-N (17-fold increase) and available phosphorus (3.2-fold increase) in soils, which in turn promoted increased growth of graminoids. These results parallel field observations, where Pinus removal is associated with invasion by non-native grasses and herbs, and suggest that legacies of Pinus on soil nutrient cycling thus indirectly promote invasion of other non-native plant species. Our findings demonstrate that multi-trophic belowground legacies are an important but hitherto largely unconsidered factor in plant community reassembly following invasive plant removal. Published by Oxford University Press on behalf of the Annals of Botany Company.

  7. Outcome and process differences between professional and nonprofessional therapists in time-limited group psychotherapy.

    Science.gov (United States)

    Burlingame, G M; Barlow, S H

    1996-10-01

    The outcome of clients who saw one of four "expert" professional group therapists selected by peer nomination or four "natural helper" nonprofessional nominated by students is contrasted in a 15-session psychotherapy group. Process measures tapping specific group and "common factors" were drawn from sessions 3, 8, and 14; outcome was assessed at pre, mid, posttreatment, and a 6-month follow-up. Results were examined by leader condition (professional vs. nonprofessional therapists) and time (group development). Virtually no reliable differences were found on measures of outcome primarily because of a floor effect on several measures. Therapist differences on the process measures tapping the "common factors" of therapeutic alliance, client expectancy, and perception of therapists were either nonsignificant or disappeared by the end of treatment. A complex picture of differences on one therapeutic factor (insight), common factor measures and subtle variation in the outcome data suggests a distinct pattern of change, however. Methodological limitations are also addressed including problems inherent in large-scale clinical-trial studies, ethical concerns raised by using nonprofessional leaders, and problems with generalizability, given the absence of significant psychopathology in group members.

  8. Evaluation of noise limits to improve image processing in soft X-ray projection microscopy.

    Science.gov (United States)

    Jamsranjav, Erdenetogtokh; Kuge, Kenichi; Ito, Atsushi; Kinjo, Yasuhito; Shiina, Tatsuo

    2017-03-03

    Soft X-ray microscopy has been developed for high resolution imaging of hydrated biological specimens due to the availability of water window region. In particular, a projection type microscopy has advantages in wide viewing area, easy zooming function and easy extensibility to computed tomography (CT). The blur of projection image due to the Fresnel diffraction of X-rays, which eventually reduces spatial resolution, could be corrected by an iteration procedure, i.e., repetition of Fresnel and inverse Fresnel transformations. However, it was found that the correction is not enough to be effective for all images, especially for images with low contrast. In order to improve the effectiveness of image correction by computer processing, we in this study evaluated the influence of background noise in the iteration procedure through a simulation study. In the study, images of model specimen with known morphology were used as a substitute for the chromosome images, one of the targets of our microscope. Under the condition that artificial noise was distributed on the images randomly, we introduced two different parameters to evaluate noise effects according to each situation where the iteration procedure was not successful, and proposed an upper limit of the noise within which the effective iteration procedure for the chromosome images was possible. The study indicated that applying the new simulation and noise evaluation method was useful for image processing where background noises cannot be ignored compared with specimen images.

  9. Co-occurring woody species have diverse hydraulic strategies and mortality rates during an extreme drought: Belowground hydraulic failure during drought

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Daniel M. [College of Natural Resources, University of Idaho, Moscow ID 83844 USA; Domec, Jean-Christophe [Bordeaux Sciences Agro, UMR INRA-ISPA 1391, Gradignan 33195 France; Nicholas School of the Environment, Duke University, Durham NC 27708 USA; Carter Berry, Z. [College of Natural Resources, University of Idaho, Moscow ID 83844 USA; Department of Natural Resources and the Environment, University of New Hampshire, Durham NH 03824 USA; Schwantes, Amanda M. [Nicholas School of the Environment, Duke University, Durham NC 27708 USA; McCulloh, Katherine A. [Department of Botany, University of Wisconsin-Madison, Madison WI 53705 USA; Woodruff, David R. [US Forest Service, Pacific Northwest Research Station, Corvallis OR 97331 USA; Wayne Polley, H. [Grassland, Soil & Water Research Laboratory USDA-Agricultural Research Service, Temple TX 76502 USA; Wortemann, Remí [INRA Nancy, UMR INRA-UL 1137 Ecologie et Ecophysiologie Forestières, Champenoux 54280 France; Swenson, Jennifer J. [Nicholas School of the Environment, Duke University, Durham NC 27708 USA; Scott Mackay, D. [Department of Geography, State University of New York, Buffalo NY 14261 USA; McDowell, Nate G. [Pacific Northwest National Laboratory, Richland WA 99352 USA; Jackson, Robert B. [Department of Earth System Science, Woods Institute for the Environment, and Precourt Institute for Energy, Stanford University, Stanford CA 94305 USA

    2018-01-29

    From 2011 to 2013, Texas experienced its worst drought in recorded history. This event provided a unique natural experiment to assess species-specific responses to extreme drought and mortality of four co-occurring woody species: Quercus fusiformis, Diospyros texana, Prosopis glandulosa and Juniperus ashei. We examined hypothesized mechanisms that could promote these species’ diverse mortality patterns using post-drought measurements on surviving trees coupled to retrospective process modeling. The species exhibited a wide range of gas exchange responses, hydraulic strategies, and mortality rates. Multiple proposed indices of mortality mechanisms were not consistent with the observed mortality patterns across species, including measures of iso/anisohydry, photosynthesis, carbohydrate depletion, and hydraulic safety margins. Large losses of growing season whole-tree conductance (driven by belowground losses of conductance), and shallower rooting depths, were associated with species that exhibited greater mortality. Based on this retrospective analysis, we suggest that species more vulnerable to drought were more likely to have succumbed to hydraulic failure belowground.

  10. 40 CFR Table 4 to Subpart Vvvvvv... - Emission Limits and Compliance Requirements for Metal HAP Process Vents

    Science.gov (United States)

    2010-07-01

    ... Requirements for Metal HAP Process Vents 4 Table 4 to Subpart VVVVVV of Part 63 Protection of Environment... of Part 63—Emission Limits and Compliance Requirements for Metal HAP Process Vents As required in § 63.11496(f), you must comply with the requirements for metal HAP process vents as shown in the...

  11. Limits of Risk Predictability in a Cascading Alternating Renewal Process Model.

    Science.gov (United States)

    Lin, Xin; Moussawi, Alaa; Korniss, Gyorgy; Bakdash, Jonathan Z; Szymanski, Boleslaw K

    2017-07-27

    Most risk analysis models systematically underestimate the probability and impact of catastrophic events (e.g., economic crises, natural disasters, and terrorism) by not taking into account interconnectivity and interdependence of risks. To address this weakness, we propose the Cascading Alternating Renewal Process (CARP) to forecast interconnected global risks. However, assessments of the model's prediction precision are limited by lack of sufficient ground truth data. Here, we establish prediction precision as a function of input data size by using alternative long ground truth data generated by simulations of the CARP model with known parameters. We illustrate the approach on a model of fires in artificial cities assembled from basic city blocks with diverse housing. The results confirm that parameter recovery variance exhibits power law decay as a function of the length of available ground truth data. Using CARP, we also demonstrate estimation using a disparate dataset that also has dependencies: real-world prediction precision for the global risk model based on the World Economic Forum Global Risk Report. We conclude that the CARP model is an efficient method for predicting catastrophic cascading events with potential applications to emerging local and global interconnected risks.

  12. Internationalization Process of Thai Office Furniture Company in India: A case study of Rockworth Public Company Limited

    OpenAIRE

    netwong, weeraya; trakarnthai, priyawat

    2010-01-01

    The purpose of this thesis is to study the internationalization process by investigate how Rockworth Public Company Limited manage internationalization in Indian market efficiently. Additionally, we aim to improve our understanding and knowledge in international business comprehensively.

  13. Propagation and diffusion-limited extinction of nonadiabatic heterogeneous flame in the SHS process

    International Nuclear Information System (INIS)

    Makino, Atsushi

    1994-01-01

    Nonadiabatic heterogeneous flame propagation and extinction in self-propagating high-temperature synthesis (SHS) are analyzed based on a premixed mode of propagation for the bulk flame supported by the nonpremixed reaction of dispersed nonmetals in the liquid metal. The formulation allows for volumetric heat loss throughout the bulk flame, finite-rate Arrhenius reaction at the particle surface, and temperature-sensitive Arrhenius mass diffusion in the liquid. Results show that, subsequent to melting of the metal, the flame structure consists of a relatively thin diffusion-consumption/convection zone followed by a relatively thick convection-loss zone, that the flame propagation rate decreases with increasing heat loss, that at a critical heat-loss rate the flame extinguishes as indicated by the characteristic turning-point behavior, that the surface reaction is diffusion limited such that the nonlinear, temperature-sensitive nature of the system is actually a consequence of the Arrhenius mass diffusion, and that extinction is sensitively affected by the mixture ratio, the degree of dilution, the initial temperature of the compact, and the size of the nonmetal particles. An explicit expression is derived for the normalized mass burning rate, which exhibits the characteristic turning point and shows that extinction occurs when this value is reduced to e -1/2 , which is the same as that for the nonadiabatic gaseous premixed flame. It is further shown that the theoretical results agree well with available experimental data, indicating that the present formulation captures the essential features of the nonadiabatic heterogeneous SHS processes and its potential for extension to describe other SHS phenomena

  14. Advanced remote sensing to quantify temperate peatland capacity for belowground carbon capture

    Science.gov (United States)

    Byrd, K. B.; Blanchard, S.; Schile, L. M.; Kolding, S.; Kelly, M.; Windham-Myers, L.; Miller, R.

    2011-12-01

    Temperate peatlands typically dominated by grasses and sedges generate among the greatest annual rates of net primary productivity (NPP, up to 4 kg C m-2) and soil carbon storage (up to 1 kg C m-2) for natural ecosystems. Belowground tissues represent 20-80% of total NPP, thus understanding the controls on belowground NPP (BNPP) in these wetland ecosystems is particularly important to quantifying peatland carbon balances. In addition, there is a growing need to quantify large-scale belowground C sequestration rates in wetlands to better understand marsh resilience to sea level rise and to help define eligibility for carbon offset credits. Since plant productivity influences wetland C budgets, combining field and remote sensing techniques for estimating above and belowground productivity of wetland vegetation over a large spatial extent will help to address these needs. We are working in a USGS long-term experimental wetland restoration site on drained peatland in the Sacramento-San Joaquin River Delta. Using the spatial variability in water depth and residence time across the 7 ha wetland, our goal is to develop practical methods to quantify and map BNPP of emergent marsh vegetation from remotely sensed estimates of aboveground plant characteristics and aboveground NPP. Field data collected on wetland plants hardstem bulrush (Schoenoplectus acutus) and cattail (Typha spp.) were coupled with reflectance data from a field spectrometer (range 350-2500 nm) every two to three weeks during the summer of 2011. We are analyzing reflectance data to develop hyperspectral indices that predict the biophysical characteristics of wetland vegetation - biomass, leaf area index (LAI), and the fraction of absorbed photosynthetically active radiation (fAPAR) - which may be used to infer belowground biomass and productivity. Soil cores and root in-growth bags were used to calculate root biomass and productivity rates. Existing allometric relationships were used to calculate

  15. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Directory of Open Access Journals (Sweden)

    Rachel L Vannette

    2013-09-01

    Full Text Available Belowground symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above and belowground herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed--which all produce toxic cardenolides--with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in above- and below-ground plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and

  16. Linking above and belowground responses to global change at community and ecosystem scales.

    Energy Technology Data Exchange (ETDEWEB)

    Antoninka, Anita [Northern Arizona University; Wolf, Julie [Northern Arizona University; Bowker, Matt [Northern Arizona University; Classen, Aimee T [ORNL; JohnsonPhD, Dr Nancy C [Northern Arizona University

    2009-01-01

    Cryptic belowground organisms are difficult to observe and their responses to global changes are not well understood. Nevertheless, there is reason to believe that interactions among above- and belowground communities may mediate ecosystem responses to global change. We used grassland mesocosms to manipulate the abundance of one important group of soil organisms, arbuscular mycorrhizal (AM) fungi, and to study community and ecosystem responses to CO2 and N enrichment. After two growing seasons, biomass responses of plant communities were recorded, and soil community responses were measured using microscopy, phospholipid fatty acids (PLFA) and community-level physiological profiles (CLPP). Ecosystem responses were examined by measuring net primary production (NPP), evapotranspiration, total soil organic matter (SOM), and extractable mineral N. Structural equation modeling was used to examine the causal relationships among treatments and response variables. We found that while CO2 and N tended to directly impact ecosystem functions (evapotranspiration and NPP, respectively), AM fungi indirectly impacted ecosystem functions by strongly influencing the composition of plant and soil communities. For example, the presence of AM fungi had a strong influence on other root and soil fungi and soil bacteria. We found that the mycotrophic status of the dominant plant species in the mesocosms determined whether the presence of AM fungi increased or decreased NPP. Mycotrophic grasses dominated the mesocosm communities during the first growing season, and thus, the mycorrhizal treatments had the highest NPP. In contrast, non-mycotrophic forbs were dominant during the second growing season and thus, the mycorrhizal treatments had the lowest NPP. The composition of the plant community strongly influenced soil N; and the composition of the soil organisms strongly influenced SOM accumulation in the mesocosms. These results show how linkages between above- and belowground communities

  17. Invasive plant suppresses the growth of native tree seedlings by disrupting belowground mutualisms.

    Directory of Open Access Journals (Sweden)

    Kristina A Stinson

    2006-05-01

    Full Text Available The impact of exotic species on native organisms is widely acknowledged, but poorly understood. Very few studies have empirically investigated how invading plants may alter delicate ecological interactions among resident species in the invaded range. We present novel evidence that antifungal phytochemistry of the invasive plant, Alliaria petiolata, a European invader of North American forests, suppresses native plant growth by disrupting mutualistic associations between native canopy tree seedlings and belowground arbuscular mycorrhizal fungi. Our results elucidate an indirect mechanism by which invasive plants can impact native flora, and may help explain how this plant successfully invades relatively undisturbed forest habitat.

  18. 40 CFR 63.500 - Back-end process provisions-carbon disulfide limitations for styrene butadiene rubber by emulsion...

    Science.gov (United States)

    2010-07-01

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

  19. Linking Above- and Belowground Dynamics in Tropical Urban Forests

    Science.gov (United States)

    Atkinson, E. E.; Marin-Spiotta, E.

    2013-12-01

    Secondary forests that emerge after a long history of agriculture can have altered plant community composition and relative abundances of different species. These forests can look and behave differently compared to pre-agricultural forests due changes in primary productivity, resource allocation, and phenology, which can significantly affect processes such as carbon accumulation and nutrient availability. Our research explores how alternative successional trajectories following intensive agricultural use affect linkages among the establishment of novel plant communities, soil nutrient availability and turnover, and soil microbial community composition and function. We hypothesize that different plant species composition due to differing land use legacies and successional trajectories would drive changes in soil microbial community structure and function, affecting soil C and N chemistry and turnover. We conducted this research in the subtropical dry forest life zone of St. Croix, U.S. Virgin Islands where island-wide abandonment of sugarcane resulted in a mosaic of sites in different stages of forest succession. We identified replicate sites with the following post-sugarcane trajectories: 1) natural forest regeneration, 2) low intensity pasture use, followed by reforestation with timber plantation, which are no longer being managed, 3) high intensity pasture use and recent natural forest regeneration, and 4) high intensity pasture use and current active grazing. During 2011-2013, we sampled soils seasonally (0-10 cm) and measured tree species composition. The successional trajectories showed distinct tree species composition. The first two trajectories yielded 40-year old mixed-species secondary forest, dominated by the dry forest tree species Melicoccus bijugatas, Guapira fragrans, Maniklara zapota, and Sideroxylon foetidissimum. The tree species Melicoccus bijugatas primarily drove differences between the first two trajectories (natural forest regeneration vs

  20. Tuberculosis Epidemiology at the Country Scale: Self-Limiting Process and the HIV Effects.

    Directory of Open Access Journals (Sweden)

    Felipe Augusto Maurin Krsulovic

    Full Text Available The global spread of the human immunodeficiency virus (HIV is the main hypothesis behind tuberculosis (TB positive trends in the last decades, according to modeling studies and World Health Organization Reports (WHO. On one hand, TB (WHO reports do not explicitly consider a modeling approach, but cover country and global TB trends. On the other hand, modeling studies usually do not cover the scale of WHO reports, because of the amount of parameters estimated to describe TB natural history. Here we combined these two principal sources of TB studies covering TB High Burden Countries (HBCs dynamics. Our main goals were: (i to detect the endogenous component of TB dynamics since 1974 for TB HBCs; and (ii to explore the HIV exogenous effects on TB models`parameters.We explored the relationship between the TB per capita population rate of change (RI and the infectious class size following an endogenous/exogenous framework. RI can be affected by intra-population processes (i.e. competition, predation and exogenous variables like HIV. We found that TB dynamics had always a strong endogenous component, represented by a negative correlation between TB population size and RI, which was captured by the discrete logistic model. Moreover, we explored the HIV exogenous effects on TB models`parameters. We found that overall the TB+HIV logistic model was more parsimonious than TB model alone, principally in the African region. Our results showed that HIV affected principally TB carrying capacity, as expected by the known HIV effects on TB natural-history. We also tested if DOTS (Directly Observed Treatment Short-Course Strategy, poverty levels and BCG (Bacillus Calmette-Guérin coverage explained the models´ residuals variances, but they did not.Since 1974, TB dynamics were categorized in distinct chronological domains, with different dynamics but nearly the same underlying mechanism: a negative relationship between RI and infected class size (i.e. self-limiting

  1. Pushing desalination recovery to the maximum limit: Membrane and thermal processes integration

    KAUST Repository

    Shahzad, Muhammad Wakil; Burhan, Muhammad; Ng, Kim Choon

    2017-01-01

    The economics of seawater desalination processes has been continuously improving as a result of desalination market expansion. Presently, reverse osmosis (RO) processes are leading in global desalination with 53% share followed by thermally driven

  2. Plutonium Equivalent Inventory for Belowground Radioactive Waste at the Los Alamos National Laboratory Technical Area 54, Area G Disposal Facility - Fiscal Year 2011

    International Nuclear Information System (INIS)

    French, Sean B.; Shuman, Robert

    2012-01-01

    The Los Alamos National Laboratory (LANL) generates radioactive waste as a result of various activities. Many aspects of the management of this waste are conducted at Technical Area 54 (TA-54); Area G plays a key role in these management activities as the Laboratory's only disposal facility for low-level radioactive waste (LLW). Furthermore, Area G serves as a staging area for transuranic (TRU) waste that will be shipped to the Waste Isolation Pilot Plant for disposal. A portion of this TRU waste is retrievably stored in pits, trenches, and shafts. The radioactive waste disposed of or stored at Area G poses potential short- and long-term risks to workers at the disposal facility and to members of the public. These risks are directly proportional to the radionuclide inventories in the waste. The Area G performance assessment and composite analysis (LANL, 2008a) project long-term risks to members of the public; short-term risks to workers and members of the public, such as those posed by accidents, are addressed by the Area G Documented Safety Analysis (LANL, 2011a). The Documented Safety Analysis uses an inventory expressed in terms of plutonium-equivalent curies, referred to as the PE-Ci inventory, to estimate these risks. The Technical Safety Requirements for Technical Area 54, Area G (LANL, 2011b) establishes a belowground radioactive material limit that ensures the cumulative projected inventory authorized for the Area G site is not exceeded. The total belowground radioactive waste inventory limit established for Area G is 110,000 PE-Ci. The PE-Ci inventory is updated annually; this report presents the inventory prepared for 2011. The approach used to estimate the inventory is described in Section 2. The results of the analysis are presented in Section 3.

  3. Fire Danger of Interaction Processes of Local Sources with a Limited Energy Capacity and Condensed Substances

    Directory of Open Access Journals (Sweden)

    Glushkov Dmitrii O.

    2015-01-01

    Full Text Available Numerical investigation of flammable interaction processes of local energy sources with liquid condensed substances has been carried out. Basic integrated characteristic values of process have been defined – ignition delay time at different energy sources parameters. Recommendations have been formulated to ensure fire safety of technological processes, characterized by possible local heat sources formation (cutting, welding, friction, metal grinding etc. in the vicinity of storage areas, transportation, transfer and processing of flammable liquids (gasoline, kerosene, diesel fuel.

  4. Interactive effects of elevated CO2 and nitrogen deposition on fatty acid molecular and isotope composition of above- and belowground tree biomass and forest soil fractions.

    Science.gov (United States)

    Griepentrog, Marco; Eglinton, Timothy I; Hagedorn, Frank; Schmidt, Michael W I; Wiesenberg, Guido L B

    2015-01-01

    Atmospheric carbon dioxide (CO2) and reactive nitrogen (N) concentrations have been increasing due to human activities and impact the global carbon (C) cycle by affecting plant photosynthesis and decomposition processes in soil. Large amounts of C are stored in plants and soils, but the mechanisms behind the stabilization of plant- and microbial-derived organic matter (OM) in soils are still under debate and it is not clear how N deposition affects soil OM dynamics. Here, we studied the effects of 4 years of elevated (13C-depleted) CO2 and N deposition in forest ecosystems established in open-top chambers on composition and turnover of fatty acids (FAs) in plants and soils. FAs served as biomarkers for plant- and microbial-derived OM in soil density fractions. We analyzed above- and belowground plant biomass of beech and spruce trees as well as soil density fractions for the total organic C and FA molecular and isotope (δ13C) composition. FAs did not accumulate relative to total organic C in fine mineral fractions, showing that FAs are not effectively stabilized by association with soil minerals. The δ13C values of FAs in plant biomass increased under high N deposition. However, the N effect was only apparent under elevated CO2 suggesting a N limitation of the system. In soil fractions, only isotope compositions of short-chain FAs (C16+18) were affected. Fractions of 'new' (experimental-derived) FAs were calculated using isotope depletion in elevated CO2 plots and decreased from free light to fine mineral fractions. 'New' FAs were higher in short-chain compared to long-chain FAs (C20-30), indicating a faster turnover of short-chain compared to long-chain FAs. Increased N deposition did not significantly affect the quantity of 'new' FAs in soil fractions, but showed a tendency of increased amounts of 'old' (pre-experimental) C suggesting that decomposition of 'old' C is retarded by high N inputs. © 2014 John Wiley & Sons Ltd.

  5. On the scaling limits of Galton Watson processes in varying environment

    NARCIS (Netherlands)

    Bansaye, V.; Simatos, F.

    2011-01-01

    Renormalized sequences of Galton Watson processes converge to Continuous State Branching Processes (CSBP), characterized by a L\\'evy triplet of two numbers and a measure. This paper investigates the case of Galton Watson processes in varying environment and provides an explicit sufficient condition

  6. Belowground Interactions Impact the Soil Bacterial Community, Soil Fertility, and Crop Yield in Maize/Peanut Intercropping Systems

    Directory of Open Access Journals (Sweden)

    Qisong Li

    2018-02-01

    Full Text Available Intercropping has been widely used to control disease and improve yield in agriculture. In this study, maize and peanut were used for non-separation intercropping (NS, semi-separation intercropping (SS using a nylon net, and complete separation intercropping (CS using a plastic sheet. In field experiments, two-year land equivalent ratios (LERs showed yield advantages due to belowground interactions when using NS and SS patterns as compared to monoculture. In contrast, intercropping without belowground interactions (CS showed a yield disadvantage. Meanwhile, in pot experiments, belowground interactions (found in NS and SS improved levels of soil-available nutrients (nitrogen (N and phosphorus (P and enzymes (urease and acid phosphomonoesterase as compared to intercropping without belowground interactions (CS. Soil bacterial community assay showed that soil bacterial communities in the NS and SS crops clustered together and were considerably different from the CS crops. The diversity of bacterial communities was significantly improved in soils with NS and SS. The abundance of beneficial bacteria, which have the functions of P-solubilization, pathogen suppression, and N-cycling, was improved in maize and peanut soils due to belowground interactions through intercropping. Among these bacteria, numbers of Bacillus, Brevibacillus brevis, and Paenibacillus were mainly increased in the maize rhizosphere. Burkholderia, Pseudomonas, and Rhizobium were mainly increased in the peanut rhizosphere. In conclusion, using maize and peanut intercropping, belowground interactions increased the numbers of beneficial bacteria in the soil and improved the diversity of the bacterial community, which was conducive to improving soil nutrient (N and P supply capacity and soil microecosystem stability.

  7. Arbuscular Mycorrhizal Fungi and Plant Chemical Defence: Effects of Colonisation on Aboveground and Belowground Metabolomes.

    Science.gov (United States)

    Hill, Elizabeth M; Robinson, Lynne A; Abdul-Sada, Ali; Vanbergen, Adam J; Hodge, Angela; Hartley, Sue E

    2018-02-01

    Arbuscular mycorrhizal fungal (AMF) colonisation of plant roots is one of the most ancient and widespread interactions in ecology, yet the systemic consequences for plant secondary chemistry remain unclear. We performed the first metabolomic investigation into the impact of AMF colonisation by Rhizophagus irregularis on the chemical defences, spanning above- and below-ground tissues, in its host-plant ragwort (Senecio jacobaea). We used a non-targeted metabolomics approach to profile, and where possible identify, compounds induced by AMF colonisation in both roots and shoots. Metabolomics analyses revealed that 33 compounds were significantly increased in the root tissue of AMF colonised plants, including seven blumenols, plant-derived compounds known to be associated with AMF colonisation. One of these was a novel structure conjugated with a malonyl-sugar and uronic acid moiety, hitherto an unreported combination. Such structural modifications of blumenols could be significant for their previously reported functional roles associated with the establishment and maintenance of AM colonisation. Pyrrolizidine alkaloids (PAs), key anti-herbivore defence compounds in ragwort, dominated the metabolomic profiles of root and shoot extracts. Analyses of the metabolomic profiles revealed an increase in four PAs in roots (but not shoots) of AMF colonised plants, with the potential to protect colonised plants from below-ground organisms.

  8. Fire Danger of Interaction Processes of Local Sources with a Limited Energy Capacity and Condensed Substances

    OpenAIRE

    Glushkov, Dmitry Olegovich; Strizhak, Pavel Alexandrovich; Vershinina, Kseniya Yurievna

    2015-01-01

    Numerical investigation of flammable interaction processes of local energy sources with liquid condensed substances has been carried out. Basic integrated characteristic values of process have been defined – ignition delay time at different energy sources parameters. Recommendations have been formulated to ensure fire safety of technological processes, characterized by possible local heat sources formation (cutting, welding, friction, metal grinding etc.) in the vicinity of storage areas, tra...

  9. Fundamental limitations of non-thermal plasma processing for internal combustion engine NOx control

    International Nuclear Information System (INIS)

    Penetrante, B.M.

    1993-01-01

    This paper discusses the physics and chemistry of non-thermal plasma processing for post-combustion NO x control in internal combustion engines. A comparison of electron beam and electrical discharge processing is made regarding their power consumption, radical production, NO x removal mechanisms, and by product formation. Can non-thermal deNO x operate efficiently without additives or catalysts? How much electrical power does it cost to operate? What are the by-products of the process? This paper addresses these fundamental issues based on an analysis of the electron-molecule processes and chemical kinetics

  10. Estimation of process capability indices from the results of limit gauge inspection of dimensional parameters in machining industry

    Science.gov (United States)

    Masterenko, Dmitry A.; Metel, Alexander S.

    2018-03-01

    The process capability indices Cp, Cpk are widely used in the modern quality management as statistical measures of the ability of a process to produce output X within specification limits. The customer's requirement to ensure Cp ≥ 1.33 is often applied in contracts. Capability indices estimates may be calculated with the estimates of the mean µ and the variability 6σ, and for it, the quality characteristic in a sample of pieces should be measured. It requires, in turn, using advanced measuring devices and well-qualified staff. From the other hand, quality inspection by attributes, fulfilled with limit gauges (go/no-go) is much simpler and has a higher performance, but it does not give the numerical values of the quality characteristic. The described method allows estimating the mean and the variability of the process on the basis of the results of limit gauge inspection with certain lower limit LCL and upper limit UCL, which separates the pieces into three groups: where X control of the manufacturing process. It is very important for improving quality of articles in machining industry through their tolerance.

  11. Strong law and central limit theorem for a process between maxima and sums

    NARCIS (Netherlands)

    Hollander, den W.Th.F.; Hooghiemstra, G.; Keane, M.S.; Resing, J.A.C.

    1991-01-01

    We prove an invariance principle for the random process (X n ) n1 given by where (Y n ) n1 are i.i.d. random variables and ( n ) n are nonrandom numbers tending upward to 1 (both in ). This process interpolates between maxima ( n 0) and sums ( n 1). Depending on the distribution ofY n and on the

  12. Strategic environmental assessment and the limits to rationality in decision making processes

    DEFF Research Database (Denmark)

    Kørnøv, Lone

    The paper focueses on the subject of rationality in decision making processes and the implications for the integration of SEA.......The paper focueses on the subject of rationality in decision making processes and the implications for the integration of SEA....

  13. Information-Limited Parallel Processing in Difficult Heterogeneous Covert Visual Search

    Science.gov (United States)

    Dosher, Barbara Anne; Han, Songmei; Lu, Zhong-Lin

    2010-01-01

    Difficult visual search is often attributed to time-limited serial attention operations, although neural computations in the early visual system are parallel. Using probabilistic search models (Dosher, Han, & Lu, 2004) and a full time-course analysis of the dynamics of covert visual search, we distinguish unlimited capacity parallel versus serial…

  14. Codigestion of manure and industrial organic waste at centralized biogas plants: process imbalances and limitations

    DEFF Research Database (Denmark)

    Bangsø Nielsen, Henrik; Angelidaki, Irini

    2008-01-01

    The present study focuses on process imbalances in Danish centralized biogas plants treating manure in combination with industrial waste. Collection of process data from various full-scale plants along with a number of interviews showed that imbalances occur frequently. High concentrations...... of ammonia or long chain fatty acids is in most cases expected to be the cause of microbial inhibitions/imbalances while foaming in the prestorage tanks and digesters is the most important practical process problem at the plants. A correlation between increased residual biogas production (suboptimal process...... conditions) and high fractions of industrial waste in the feedstock was also observed. The process imbalances and suboptimal conditions are mainly allowed to occur due to 1) inadequate knowledge about the waste composition, 2) inadequate knowledge about the waste degradation characteristics, 3) inadequate...

  15. Mechanical joining of materials with limited ductility: Analysis of process-induced defects

    Science.gov (United States)

    Jäckel, M.; Coppieters, S.; Hofmann, M.; Vandermeiren, N.; Landgrebe, D.; Debruyne, D.; Wallmersberger, T.; Faes, K.

    2017-10-01

    The paper shows experimental and numerical analyses of the clinching process of 6xxx series aluminum sheets in T6 condition and the self-pierce riveting process of an aluminum die casting. In the experimental investigations the damage behavior of the materials when using different tool parameters is analyzed. The focus of the numerical investigations is the damage prediction by a comparison of different damage criteria. Moreover, strength-and fatigue tests were carried out to investigate the influence of the joining process-induced damages on the strength properties of the joints.

  16. Exploring the limits: A low-pressure, low-temperature Haber-Bosch process

    Science.gov (United States)

    Vojvodic, Aleksandra; Medford, Andrew James; Studt, Felix; Abild-Pedersen, Frank; Khan, Tuhin Suvra; Bligaard, T.; Nørskov, J. K.

    2014-04-01

    The Haber-Bosch process for ammonia synthesis has been suggested to be the most important invention of the 20th century, and called the ‘Bellwether reaction in heterogeneous catalysis’. We examine the catalyst requirements for a new low-pressure, low-temperature synthesis process. We show that the absence of such a process for conventional transition metal catalysts can be understood as a consequence of a scaling relation between the activation energy for N2 dissociation and N adsorption energy found at the surface of these materials. A better catalyst cannot obey this scaling relation. We define the ideal scaling relation characterizing the most active catalyst possible, and show that it is theoretically possible to have a low pressure, low-temperature Haber-Bosch process. The challenge is to find new classes of catalyst materials with properties approaching the ideal, and we discuss the possibility that transition metal compounds have such properties.

  17. Age Differences in Information Use While Making Decisions: Resource Limitations or Processing Differences?

    Science.gov (United States)

    Jacobs-Lawson, Joy M; Schumacher, Mitzi M; Wackerbarth, Sarah B

    2016-09-20

    Recent research on the decision-making abilities of older adults has shown that they use less information than young adults. One explanation ascribes this age difference to reductions in cognitive abilities with age. The article includes three experimental studies that focused on determining the conditions in which older and young adults would display dissimilar information processing characteristics. Findings from Studies 1 and 2 demonstrated that older adults are not necessarily at greater disadvantage than young adults in decision contexts that demand more information processing resources. Findings from Study 3 indicated that older adults when faced with decisions that require greater processing are likely to use a strategy that reduces the amount of information needed, whereas younger adults rely on strategies that utilize more resources. Combined the findings indicate that older adults change their decision-making strategies based on the context and information provided. Furthermore, support is provided for processing difference. © The Author(s) 2016.

  18. Changes in carbon allocation to aboveground versus belowground forest components is driven by a trade-off involving mycorrhizal fungi, not fine roots

    Science.gov (United States)

    Ouimette, A.; Ollinger, S. V.; Hobbie, E. A.; Lepine, L. C.; Stephens, R.; Rowe, R.; Vadeboncoeur, M. A.; Tumber-Davila, S. J.

    2017-12-01

    Species composition and resource availability exert a strong influence on the dynamics of carbon allocation among different forest ecosystem components. Recent work in temperate forests has highlighted a tradeoff between carbon allocation to aboveground woody tissues (access to light), and belowground to fine roots (access to soil nutrients). Although root-associated mycorrhizal fungi are crucial for N acquisition and can receive 20% or more of annual net primary production, most studies fail to explicitly include carbon allocation to mycorrhizal fungi. In part, this is due to the inherent difficulties in accurately quantifying fungal production. We took several approaches to quantify production of mycorrhizal fungi, including a carbon budget approach and isotopic techniques. Here we present data on patterns of carbon allocation to aboveground (wood and foliar production), and belowground components (production of fine roots and mycorrhizal fungi), across temperate forest stands spanning a range of nitrogen availability and species composition. We found that as the proportion of conifer species decreased, and stand nitrogen availability increased, both the absolute amount and the fraction of net primary production increased for foliage, aboveground wood, and fine roots ("a rising tide lifts all boats"). While allocation to plant pools increased, allocation to mycorrhizal fungi significantly decreased with decreasing conifer dominance and increasing soil nitrogen availability. We did not find a strong trade-off between carbon allocation to fine roots and aboveground wood or foliage. Instead, a negative relationship is seen between allocation to mycorrhizal fungi and other plant pools. Effort to estimate carbon allocation to mycorrhizal fungi is important for gaining a more complete understanding of how ecosystems respond to changes in growth-limiting resources.

  19. Cogongrass ( Imperata cylindrica ) affects above- and belowground processes in commercial loblolly pine ( Pinus taeda ) stands

    Science.gov (United States)

    Adam N. Trautwig; Lori G. Eckhardt; Nancy J. Loewenstein; Jason D. Hoeksema; Emily A. Carter; Ryan L. Nadel

    2017-01-01

    Cogongrass (Imperata cylindrica), an invasive grass species native to Asia, has been shown to reduce tree vigor in loblolly pine (Pinus taeda) plantations, which comprise more than 50% of growing stock in commercial forests of the United States. I. cylindrica produces exudates with possible allelopathic effects that may influence abundance of P. taeda symbionts, such...

  20. Limitation of the EIA Process for the assessment of nuclear fuel waste disposal in Canada

    International Nuclear Information System (INIS)

    Murphy, B.L.; Kuhn, R.G.

    1999-01-01

    The Canadian environmental impact assessment process for the Nuclear Fuel Waste Management and Disposal Concept was completed in 1994. Almost four years later, in February 1998, the Review Panel released its report. The viewpoints of those who participated in the assessment process is archived in the thousands of pages of hearing testimony, meeting transcripts and written briefs. One of the most contentious issues raised, and one that continues to plague management in Canada, is the debate surrounding how the problem of NFW waste management should be defined. The purpose of this paper is to critically assess the problem frame of the Canadian NFW management disposal concept EIS. This will be accomplished through an analysis of stakeholder participation and views, and through an evaluation of the range and nature of the information considered legitimate or constrained in the Canadian process

  1. Limitation of the EIA Process for the assessment of nuclear fuel waste disposal in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, B.L.; Kuhn, R.G. [Guelph Univ., ON (Canada). Dept. of Geography

    1999-12-01

    The Canadian environmental impact assessment process for the Nuclear Fuel Waste Management and Disposal Concept was completed in 1994. Almost four years later, in February 1998, the Review Panel released its report. The viewpoints of those who participated in the assessment process is archived in the thousands of pages of hearing testimony, meeting transcripts and written briefs. One of the most contentious issues raised, and one that continues to plague management in Canada, is the debate surrounding how the problem of NFW waste management should be defined. The purpose of this paper is to critically assess the problem frame of the Canadian NFW management disposal concept EIS. This will be accomplished through an analysis of stakeholder participation and views, and through an evaluation of the range and nature of the information considered legitimate or constrained in the Canadian process.

  2. Quantifying above- and belowground biomass carbon loss with forest conversion in tropical lowlands of Sumatra (Indonesia).

    Science.gov (United States)

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Meriem, Selis; Hertel, Dietrich

    2015-10-01

    Natural forests in South-East Asia have been extensively converted into other land-use systems in the past decades and still show high deforestation rates. Historically, lowland forests have been converted into rubber forests, but more recently, the dominant conversion is into oil palm plantations. While it is expected that the large-scale conversion has strong effects on the carbon cycle, detailed studies quantifying carbon pools and total net primary production (NPPtotal ) in above- and belowground tree biomass in land-use systems replacing rainforest (incl. oil palm plantations) are rare so far. We measured above- and belowground carbon pools in tree biomass together with NPPtotal in natural old-growth forests, 'jungle rubber' agroforests under natural tree cover, and rubber and oil palm monocultures in Sumatra. In total, 32 stands (eight plot replicates per land-use system) were studied in two different regions. Total tree biomass in the natural forest (mean: 384 Mg ha(-1) ) was more than two times higher than in jungle rubber stands (147 Mg ha(-1) ) and >four times higher than in monoculture rubber and oil palm plantations (78 and 50 Mg ha(-1) ). NPPtotal was higher in the natural forest (24 Mg ha(-1)  yr(-1) ) than in the rubber systems (20 and 15 Mg ha(-1)  yr(-1) ), but was highest in the oil palm system (33 Mg ha(-1)  yr(-1) ) due to very high fruit production (15-20 Mg ha(-1)  yr(-1) ). NPPtotal was dominated in all systems by aboveground production, but belowground productivity was significantly higher in the natural forest and jungle rubber than in plantations. We conclude that conversion of natural lowland forest into different agricultural systems leads to a strong reduction not only in the biomass carbon pool (up to 166 Mg C ha(-1) ) but also in carbon sequestration as carbon residence time (i.e. biomass-C:NPP-C) was 3-10 times higher in the natural forest than in rubber and oil palm plantations. © 2015 John Wiley & Sons Ltd.

  3. Changes in Soil Carbon Stocks and Fluxes in Response to Altered Above- and Belowground Vegetation Inputs

    Science.gov (United States)

    Marañón-Jiménez, S.; Schuetze, C.; Cuntz, M.; García-Quirós, I.; Dienstbach, L.; Schrumpf, M.; Rebmann, C.

    2016-12-01

    The stimulation of vegetation productivity in response to rising atmospheric CO2 concentrations can potentially compensate climate change feedbacks. However, this will depend on the allocation of C resources of vegetation into biomass production versus root exudates and on the feedbacks with soil microorganisms. These dynamic adjustments of vegetation will result on changes in above- and belowground productivity and on the amount of C exported to root exudates. Consequent alteration of litter and rhizosphere detritus inputs to the soil and their interaction on controlling soil C sequestration capacity has been, however, rarely assessed. We hypothesize that above- and belowground vegetation exert a synergistic control of soil CO2 emissions, and that the activation of soil organic matter mineralization by the addition of labile organic substrates (i.e.: the priming effect) is altered by changes in the amount and in the quality of the carbon inputs. In order to elucidate these questions, different levels of litter addition were implemented on trenched (root exclusion) and non-trenched plots (with roots) in a temperate deciduous forest. Changes in the sensitivity of soil respiration to temperature and moisture were detected by measuring CO2 fluxes continuously at high temporal resolution with automatic chambers, whereas the spatial and seasonal variability was determined using portable chambers. Annual changes in soil carbon and nitrogen stocks provide additional information on the soil carbon sequestration in response to above- and belowground inputs. Both roots and litter inputs significantly enhanced soil CO2 effluxes soon after the implementation of the experiment. We detected synergistic effects between roots and litter inputs on soil CO2 emissions: When roots were present, carbon mineralized in response to litter addition was much higher than the total amount of carbon added in litter (ca. 170 g C m-2 y-1). Preliminary results of this study suggest that labile

  4. Visuo-spatialWorking Memory as a Limited Resource of Cognitive Processing

    Science.gov (United States)

    Zimmer, Hubert D.; Münzer, Stefan; Umla-Runge, Katja

    Working memory is considered a cognitive component that mainly serves two functions. It temporarily maintains information that was either perceived but is no longer present in the environment, or that was internally generated, and it supplies a work space for transforming and manipulating elements of perception and thinking. Both functions are relevant for a successful interaction with the environment and it is therefore not surprising that WM is a central topic of research in the field of general psychology. This interest is further increased by the fact that WM is seen as a limited resource that constrains cognitive performances.

  5. Influence of presence and spatial arrangement of belowground insects on host-plant selection of aboveground insects: a field study

    NARCIS (Netherlands)

    Soler, J.J.; Schaper, S.V.; Bezemer, T.M.; Cortesero, A.M.; Hoffmeister, T.S.; Van der Putten, W.H.; Vet, L.E.M.; Harvey, J.A.

    2009-01-01

    1. Several studies have shown that above- and belowground insects can interact by influencing each others growth, development, and survival when they feed on the same host-plant. In natural systems, however, insects can make choices on which plants to oviposit and feed. A field experiment was

  6. Interactions between above- and belowground biota: importance for small-scale vegetation mosaics in a grassland ecosystem

    NARCIS (Netherlands)

    Blomqvist, M.M.; Olff, H.; Blaauw, M.B.; Bongers, T.; Van der Putten, W.H.

    2000-01-01

    Grasslands are often characterised by small-scale mosaics in plant community composition that contribute to their diversity. Although above- and belowground biota can both cause such mosaics, few studies have addressed their interacting effects. We studied multi-trophic interactions between

  7. Interactions between above- and belowground biota : importance for small-scale vegetation mosaics in a grassland ecosystem

    NARCIS (Netherlands)

    Blomqvist, N.M.; Olff, H.; Blaauw, M.B.; Bongers, T.; Putten, van der W.H.

    2000-01-01

    Grasslands are often characterised by small-scale mosaics in plant community composition that contribute to their diversity. Although above- and belowground biota can both cause such mosaics, few studies have addressed their interacting effects. We studied multi-trophic interactions between

  8. Examination of Below-Ground Structure and Soil Respiration Rates of Stable and Deteriorating Salt Marshes in Jamaica Bay (NY)

    Science.gov (United States)

    CAT scan imaging is currently being used to examine below-ground peat and root structure in cores collected from salt marshes of Jamaica Bay, part of the Gateway National Recreation Area (NY). CAT scans or Computer-Aided Tomography scans use X-ray equipment to produce multiple i...

  9. Effects of above- and below-ground competition from shrubs on photosynthesis, transpiration and growth in Quercus robur L

    Science.gov (United States)

    Anna M. Jensen; Magnus Lof; Emile S. Gardiner

    2011-01-01

    For a tree seedling to successfully establish in dense shrubbery, it must maintain function under heterogeneous resource availability. We evaluated leaf-level acclimation in photosynthetic capacity, seedling-level transpiration, and seedling morphology and growth to gain an understanding of the effects of above- and below-ground competition on Quercus robur seedlings....

  10. Systemic above- and belowground cross talk: hormone-based responses triggered by Heterodera schachtii and shoot herbivores in Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Kammerhofer, N.; Egger, B.; Dobrev, Petre; Vaňková, Radomíra; Hofmann, J.; Schausberger, P.; Wieczorek, K.

    2015-01-01

    Roč. 66, č. 22 (2015), s. 7005-7017 ISSN 0022-0957 R&D Projects: GA MŠk LD14120 Institutional support: RVO:61389030 Keywords : Aboveground–belowground interactions * Frankliniella occidentalis * herbivores Subject RIV: EF - Botanics Impact factor: 5.677, year: 2015

  11. Exploitation of a self-limiting process for reproducible formation of ultrathin Ni1-xPtx silicide films

    International Nuclear Information System (INIS)

    Zhang Zhen; Zhu Yu; Rossnagel, Steve; Murray, Conal; Jordan-Sweet, Jean; Yang, Bin; Gaudet, Simon; Desjardins, Patrick; Kellock, Andrew J.; Ozcan, Ahmet; Zhang Shili; Lavoie, Christian

    2010-01-01

    This letter reports on a process scheme to obtain highly reproducible Ni 1-x Pt x silicide films of 3-6 nm thickness formed on a Si(100) substrate. Such ultrathin silicide films are readily attained by sputter deposition of metal films, metal stripping in wet chemicals, and final silicidation by rapid thermal processing. This process sequence warrants an invariant amount of metal intermixed with Si in the substrate surface region independent of the initial metal thickness, thereby leading to a self-limiting formation of ultrathin silicide films. The crystallographic structure, thickness, uniformity, and morphological stability of the final silicide films depend sensitively on the initial Pt fraction.

  12. Limit theory for the sample autocorrelations and extremes of a GARCH (1,1) process

    NARCIS (Netherlands)

    Mikosch, T; Starica, C

    2000-01-01

    The asymptotic theory for the sample autocorrelations and extremes of a GARCH(I, 1) process is provided. Special attention is given to the case when the sum of the ARCH and GARCH parameters is close to 1, that is, when one is close to an infinite Variance marginal distribution. This situation has

  13. Pushing desalination recovery to the maximum limit: Membrane and thermal processes integration

    KAUST Repository

    Shahzad, Muhammad Wakil

    2017-05-05

    The economics of seawater desalination processes has been continuously improving as a result of desalination market expansion. Presently, reverse osmosis (RO) processes are leading in global desalination with 53% share followed by thermally driven technologies 33%, but in Gulf Cooperation Council (GCC) countries their shares are 42% and 56% respectively due to severe feed water quality. In RO processes, intake, pretreatment and brine disposal cost 25% of total desalination cost at 30–35% recovery. We proposed a tri-hybrid system to enhance overall recovery up to 81%. The conditioned brine leaving from RO processes supplied to proposed multi-evaporator adsorption cycle driven by low temperature industrial waste heat sources or solar energy. RO membrane simulation has been performed using WinFlow and IMSDesign commercial softwares developed by GE and Nitto. Detailed mathematical model of overall system is developed and simulation has been conducted in FORTRAN. The final brine reject concentration from tri-hybrid cycle can vary from 166,000ppm to 222,000ppm if RO retentate concentration varies from 45,000ppm to 60,000ppm. We also conducted economic analysis and showed that the proposed tri-hybrid cycle can achieve highest recovery, 81%, and lowest energy consumption, 1.76kWhelec/m3, for desalination reported in the literature up till now.

  14. Limit theorems for functionals of mixing processes with applications to U-statistics and dimension estimation

    NARCIS (Netherlands)

    Borovkova, Svetlana; Burton, Robert; Dehling, Herold

    2001-01-01

    In this paper we develop a general approach for investigating the asymptotic distribution of functional Xn = f((Zn+k)k∈z) of absolutely regular stochastic processes (Zn)n∈z. Such functional occur naturally as orbits of chaotic dynamical systems, and thus our results can be used to study

  15. Ozone/electron beam process for water treatment: design, limitations and economic considerations

    International Nuclear Information System (INIS)

    Gehringer, P.; Eschweiler, H.

    1996-01-01

    Electron beam irradiation of water is the easiest way to generate OH free radicals but the efficiency of the irradiation process as advanced oxidation process (AOP) is deteriorated by reducing species formed simultaneously with the OH free radicals. Addition of ozone to the water before or during irradiation improves the efficiency essentially by converting the reducing species into OH free radicals and turning by that the irradiation process into a full AOP. The main reaction pathways of the primary species formed by the action of ionizing radiation on water in a natural groundwater with and without the presence of ozone are reviewed. Based on these data an explanation of both the dose rate effect and the ozone effect is attempted. New data is presented which illustrates the effect of alkalinity on the way in which ozone is introduced into the water, and the impact of both water matrix and chemical structure of the pollutants to the efficacy of the ozone/electron beam process. (author)

  16. The improved heat integration of cement production under limited process conditions: A case study for Croatia

    International Nuclear Information System (INIS)

    Boldyryev, Stanislav; Mikulčić, Hrvoje; Mohorović, Zoran; Vujanović, Milan; Krajačić, Goran; Duić, Neven

    2016-01-01

    Given that cement is the most widely used material for housing and modern infrastructure needs, this paper analyses the energy efficiency of the cement manufacturing processes for a particular cement plant. The cement industry is one of the largest consumers of carbon-containing primary energy sources and one of the primary polluters of the environment, emitting approximately 5% of global pollution. Energy consumption represents the largest part of the production cost for cement factories and has a significant influence on product prices. Given that it is realised in modern society that infrastructural projects lead to a higher level of economy and sustainability for countries, reducing the production cost in the cement industry is a very important problem. The authors analysed the energy consumption of a particular cement factory in Croatia to determine the minimum energy targets of production and proposed pathways to improve energy efficiency. The Process Integration approach was used in this study. Nevertheless, the features of the cement factory forced the research to update its methodological steps to propose real pathways for a retrofit project with the aim of achieving the optimal minimum temperature difference between process streams. There are various streams, including those that contain solid particles, gas and air streams, and streams, that should be cooled down rapidly; these facts become more complicated by the special construction of the process equipment, which causes heat transfer between some streams to be impossible. The main objective of this paper is to determine the potential of real energy savings and propose a solution for a new concept of heat exchanger network (HEN) that avoids the process traps and provides a feasible retrofit. The maximum heat recovery of that production of a particular type of cement was determined and improved when a HEN was built. The authors conclude that the energy consumption of the cement factory can be reduced by

  17. The integration process of immigrants: limits and new contributions for a more comprehensive study

    Directory of Open Access Journals (Sweden)

    Yolanda González- Rábago

    2014-02-01

    Full Text Available The integration process of immigrants is a complex issue of conceptualization and extensive discussion both in the field of public policy and from the academia. The alleged European consensus about integration has only been in the comfortable speech of bidirectionality and the study of the integration process in host societies has been raised ever from quantifier and objectivist parameters that are not able to grasp the diversity of thereof. Furthermore, the study of integration has overlooked the importance of the society of origin and the link that immigrants remain with them, focusing only on the host society as a place of integration. In this paper I propose the extension of the look on the integration by incorporating the perspective of origin and the subjectivity of the immigrants as an actor with the capacity to question, decide and change the patterns and contexts in which integration occurs.

  18. Organization of school work in focus: the limits of antidemocratic inheritance and potential of participatory processes

    Directory of Open Access Journals (Sweden)

    Maria Vieira Silva

    2011-10-01

    Full Text Available Historically, democratic and participatory processes in the Brazilian society, and specifically in school, have been permeated by intermittences, weaknesses and resistances caused by multiple determinations. The text focuses on aspects concerningthe organization of education work through two lines of analysis: the first angle refers to the social constructs of structural and organic nature linked to relations of power andanti-democratic practices of the society in general. The second angle reference to a kindof ethnographic research, conducted within a public school in the Minas Gerais state. We seek to grasp the challenges on building practices and strategies in support of the participatory processes of the school community in the pedagogic project design and in the operation of the school board. We propose, with these analyses, to contribute withreflections on the status of teachers, as a subject, in the school organization throughconnections with work activities related to their everyday practice.

  19. A below-ground herbivore shapes root defensive chemistry in natural plant populations.

    Science.gov (United States)

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Théo; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-03-30

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root latex secondary metabolites across 21 central European T. officinale field populations. By cultivating offspring of these populations, we show that both heritable variation and phenotypic plasticity contribute to the observed differences. Furthermore, we demonstrate that the production of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) is costly in the absence, but beneficial in the presence of M. melolontha, resulting in divergent selection of TA-G. Our results highlight the role of soil-dwelling insects for the evolution of plant defences in nature. © 2016 The Author(s).

  20. Belowground ectomycorrhizal fungal communities respond to liming in three southern Swedish coniferous forest stands

    DEFF Research Database (Denmark)

    Kjøller, Rasmus; Clemmensen, Karina

    2009-01-01

    In this study we report on changes in the belowground ectomycorrhizal fungal communities in southern Swedish coniferous forests as a consequence of liming with 3-7 ton limestone per hectare 16 years prior to the study. A total of 107 ectomycorrhizal fungi were identified from 969 independently...... sampled root tips by sequencing the internal transcribed spacer region of the ribosomal DNA. Forty, 59 and 51 species were identified in three pine and spruce forests. Within all sites only about 25% of the species overlapped between the limed and the reference areas. However, the most abundant species...... were often found in both limed and reference plots and 60-70% of the root tips at each site were colonised by species occurring in both limed and reference plots. Across all three sites, fungal species belonging to the genus Tylospora and the order Pezizales became significantly more frequent in limed...

  1. Cardenolides, induced responses, and interactions between above- and belowground herbivores of milkweed (Asclepias spp.).

    Science.gov (United States)

    Rasmann, Sergio; Agrawal, Anurag A; Cook, Susan C; Erwin, Alexis C

    2009-09-01

    Theory has long predicted allocation patterns for plant defense against herbivory, but only recently have both above- and belowground plant defenses been considered simultaneously. Milkweeds in the genus Asclepias are a classic chemically defended clade of plants with toxic cardenolides (cardiac glycosides) and pressurized latex employed as anti-herbivore weapons. Here we combine a comparative approach to investigate broadscale patterns in allocation to root vs. shoot defenses across species with a species-specific experimental approach to identify the consequences of defense allocational shifts on a specialist herbivore. Our results show phylogenetic conservatism for inducibility of shoot cardenolides by an aboveground herbivore, with only four closely related tropical species showing significant induction; the eight temperate species examined were not inducible. Allocation to root and shoot cardenolides was positively correlated across species, and this relationship was maintained after accounting for phylogenetic nonindependence. In contrast to long-standing theoretical predictions, we found no evidence for a trade-off between constitutive and induced cardenolides; indeed the two were positively correlated across species in both roots and shoots. Finally, specialist root and shoot herbivores of common milkweed (A. syriaca) had opposing effects on latex production, and these effects had consequences for caterpillar growth consistent with latex providing resistance. Although cardenolides were not affected by our treatments, A. syriaca allocated 40% more cardenolides to shoots over roots. We conclude that constitutive and inducible defenses are not trading off across plant species, and shoots of Asclepias are more inducible than roots. Phylogenetic conservatism cannot explain the observed patterns of cardenolide levels across species, but inducibility per se was conserved in a tropical clade. Finally, given that above- and belowground herbivores can systemically

  2. Above- and belowground linkages in Sphagnum peatland: climate warming affects plant-microbial interactions.

    Science.gov (United States)

    Jassey, Vincent E J; Chiapusio, Geneviève; Binet, Philippe; Buttler, Alexandre; Laggoun-Défarge, Fatima; Delarue, Frédéric; Bernard, Nadine; Mitchell, Edward A D; Toussaint, Marie-Laure; Francez, André-Jean; Gilbert, Daniel

    2013-03-01

    Peatlands contain approximately one third of all soil organic carbon (SOC). Warming can alter above- and belowground linkages that regulate soil organic carbon dynamics and C-balance in peatlands. Here we examine the multiyear impact of in situ experimental warming on the microbial food web, vegetation, and their feedbacks with soil chemistry. We provide evidence of both positive and negative impacts of warming on specific microbial functional groups, leading to destabilization of the microbial food web. We observed a strong reduction (70%) in the biomass of top-predators (testate amoebae) in warmed plots. Such a loss caused a shortening of microbial food chains, which in turn stimulated microbial activity, leading to slight increases in levels of nutrients and labile C in water. We further show that warming altered the regulatory role of Sphagnum-polyphenols on microbial community structure with a potential inhibition of top predators. In addition, warming caused a decrease in Sphagnum cover and an increase in vascular plant cover. Using structural equation modelling, we show that changes in the microbial food web affected the relationships between plants, soil water chemistry, and microbial communities. These results suggest that warming will destabilize C and nutrient recycling of peatlands via changes in above- and belowground linkages, and therefore, the microbial food web associated with mosses will feedback positively to global warming by destabilizing the carbon cycle. This study confirms that microbial food webs thus constitute a key element in the functioning of peatland ecosystems. Their study can help understand how mosses, as ecosystem engineers, tightly regulate biogeochemical cycling and climate feedback in peatlands. © 2012 Blackwell Publishing Ltd.

  3. Mind the Roots: Phenotyping Below-Ground Crop Diversity and Its Influence on Final Yield

    Science.gov (United States)

    Nieters, C.; Guadagno, C. R.; Lemli, S.; Hosseini, A.; Ewers, B. E.

    2017-12-01

    Changes in global climate patterns and water regimes are having profound impacts on worldwide crop production. An ever-growing population paired with increasing temperatures and unpredictable periods of severe drought call for accurate modeling of future crop yield. Although novel approaches are being developed in high-throughput, above-ground image phenotyping, the below-ground plant system is still poorly phenotyped. Collection of plant root morphology and hydraulics are needed to inform mathematical models to reliably estimate yields of crops grown in sub-optimal conditions. We used Brassica rapa to inform our model as it is a globally cultivated crop with several functionally diverse cultivars. Specifically, we use 7 different accessions from oilseed (R500 and Yellow Sarson), leafy type (Pac choi and Chinese cabbage), a vegetable turnip, and two Wisconsin Fast Plants (Imb211 and Fast Plant self-compatible), which have shorter life cycles and potentially large differences in allocation to roots. Bi-weekly, we harvested above and below-ground biomass to compare the varieties in terms of carbon allocation throughout their life cycle. Using WinRhizo software, we analyzed root system length and surface area to compare and contrast root morphology among cultivars. Our results confirm that root structural characteristics are crucial to explain plant water use and carbon allocation. The root:shoot ratio reveals a significant (p physiological traits such as gas exchange, chlorophyll content, and chlorophyll a fluorescence. A thorough analysis of the root system will clarify carbon dynamics and hydraulics at the whole-plant level, improving final yield predictions.

  4. Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock

    International Nuclear Information System (INIS)

    Zheng, Liange; Rutqvist, Jonny; Kim, Kunhwi; Houseworth, Jim

    2015-01-01

    The focus of research within the UFD Campaign is on repository-induced interactions that may affect the key safety characteristics of an argillaceous rock. These include thermal-hydrological-mechanical-chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer minerals and petrophysical characteristics, particularly the impacts of induced temperature rise caused by waste heat.

  5. Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Liange [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kim, Kunhwi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Houseworth, Jim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-07-01

    The focus of research within the UFD Campaign is on repository-induced interactions that may affect the key safety characteristics of an argillaceous rock. These include thermal-hydrological-mechanical-chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer minerals and petrophysical characteristics, particularly the impacts of induced temperature rise caused by waste heat.

  6. Ultrasound based monitoring of the injection moulding process - Methods, applications and limitations

    International Nuclear Information System (INIS)

    Praher, B.; Straka, K.; Usanovic, J.; Steinbichler, G.

    2014-01-01

    We developed novel non-invasive ultrasound based systems for the measurement of temperature distributions in the screw-ante chamber, the detection of unmelted granules and for the monitoring of the plasticizing process along the screw channel. The temperature of the polymer melt stored in the screw ante-chamber after the plasticization should be homogeneous. However, in reality the polymer melt in the screw ante-chamber is not homogeneous. Due to the fact the sound velocity in a polymer melt is temperature depending, we developed a tomography system using the measured transit times of ultrasonic pulses along different sound paths for calculating the temperature distribution in radial direction of a polymer melt in the screw ante-chamber of an injection moulding machine. For the detection of unmelted granules in the polymer melt we implemented an ultrasound transmission measurement. By analyzing the attenuation of the received pulses it is possible to detect unwanted inclusions. For the monitoring of the plasticizing process in the channels of the screw an ultrasonic pulse is transmitted into the barrel. By analyzing the reflected pulses it is possible to estimate solid bed and melt regions in the screw channel. The proposed systems were tested for accuracy and validity by simulations and test measurements

  7. Psychophysical Estimates of Frequency Discrimination: More than Just Limitations of Auditory Processing

    Directory of Open Access Journals (Sweden)

    Beate Sabisch

    2013-07-01

    Full Text Available Efficient auditory processing is hypothesized to support language and literacy development. However, behavioral tasks used to assess this hypothesis need to be robust to non-auditory specific individual differences. This study compared frequency discrimination abilities in a heterogeneous sample of adults using two different psychoacoustic task designs, referred to here as: 2I_6A_X and 3I_2AFC designs. The role of individual differences in nonverbal IQ (NVIQ, socioeconomic status (SES and musical experience in predicting frequency discrimination thresholds on each task were assessed using multiple regression analyses. The 2I_6A_X task was more cognitively demanding and hence more susceptible to differences specifically in SES and musical training. Performance on this task did not, however, relate to nonword repetition ability (a measure of language learning capacity. The 3I_2AFC task, by contrast, was only susceptible to musical training. Moreover, thresholds measured using it predicted some variance in nonword repetition performance. This design thus seems suitable for use in studies addressing questions regarding the role of auditory processing in supporting language and literacy development.

  8. Analysis of counter current flow limitation during the cooling process at the rectangular narrow boundary

    International Nuclear Information System (INIS)

    Nur Rahmad Yusuf

    2013-01-01

    Experimental studies to study the mechanism of boiling heat transfer in narrow rectangular channel under severe accident scenarios of TMI-2 nuclear power plant necessary for the understanding of management-related accidents. The research aims to obtain heat flux values and the critical heat flux (CHF) during the process of boiling heat transfer in narrow rectangular channel. Research methods experimentally using the HEATING-02 test section with cooling fluid is water temperature 98 °C. Experiments performed by varying the hot plate initial temperature of 100 °C, 200 °C and 300 °C with channel size 1 mm. Boiling during the cooling process was recorded by a transient temperature on the hot plate. Temperature data used to calculate the heat flux and wall temperature, the results are represented through the boiling curve. The results show that the higher plate temperature, the narrower width of the curve will be narrower and its mean that the plate surface cooling time will be slower. Results visualization is seen that the CCF occurred at the hot plate initial temperature of 100 °C, 200 °C and 300 °C with channel size 1 mm. (author)

  9. Electron beam welding: study of process capabilities and limitations towards development of nuclear components

    International Nuclear Information System (INIS)

    Vadolia, Gautam; Singh, Kongkham Premjit

    2015-01-01

    Electron beam (EB) welding technology is an established and widely adopted technique in nuclear research and development area. Electron Beam welding is thought of as a candidate process for ITER Vacuum Vessel Fabrication. Dhruva Reactor @ BARC, Mumbai and Niobium Superconducting accelerator Cavitity @ BARC has adopted the EB welding technique as a fabrication route. The highly concentrated energy input of the electron beam has added the advantages over the conventional welding as being less HAZ and provided smooth and clean surface. EB Welding has also been used for the joining of various reactive and refractory materials. EB system as heat source has also been used for vacuum brazing application. The Welding Institute (TWI) has demonstrated that EBW is potentially suitable to produce high integrity joints in 50 mm pure copper. TWI has also examined 150 kV Reduced Pressure Electron Beam (RPEB) gun in welding 140 mm and 147 mm thickness Nuclear Reactor Pressure Vessel Steel (SA 508 grade). EBW in 10 mm thick SS316 plates were studied at IPR and results were encouraging. In this paper, the pros and cons and role of electron beam process will be studied to analyze the importance of electron beam welding in nuclear components fabrication. Importance of establishing the high precision Wire Electro Discharge Machining (WEDM) facility will also be discussed. (author)

  10. Ultrasound based monitoring of the injection moulding process - Methods, applications and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Praher, B., E-mail: bernhard.praher@jku.at, E-mail: klaus.straka@jku.at, E-mail: jesenka.usanovic@jku.at, E-mail: georg.steinbichler@jku.at; Straka, K., E-mail: bernhard.praher@jku.at, E-mail: klaus.straka@jku.at, E-mail: jesenka.usanovic@jku.at, E-mail: georg.steinbichler@jku.at; Usanovic, J., E-mail: bernhard.praher@jku.at, E-mail: klaus.straka@jku.at, E-mail: jesenka.usanovic@jku.at, E-mail: georg.steinbichler@jku.at; Steinbichler, G., E-mail: bernhard.praher@jku.at, E-mail: klaus.straka@jku.at, E-mail: jesenka.usanovic@jku.at, E-mail: georg.steinbichler@jku.at [Institute of Polymer Injection Moulding and Process Automation, Johannes Kepler University Linz (Austria)

    2014-05-15

    We developed novel non-invasive ultrasound based systems for the measurement of temperature distributions in the screw-ante chamber, the detection of unmelted granules and for the monitoring of the plasticizing process along the screw channel. The temperature of the polymer melt stored in the screw ante-chamber after the plasticization should be homogeneous. However, in reality the polymer melt in the screw ante-chamber is not homogeneous. Due to the fact the sound velocity in a polymer melt is temperature depending, we developed a tomography system using the measured transit times of ultrasonic pulses along different sound paths for calculating the temperature distribution in radial direction of a polymer melt in the screw ante-chamber of an injection moulding machine. For the detection of unmelted granules in the polymer melt we implemented an ultrasound transmission measurement. By analyzing the attenuation of the received pulses it is possible to detect unwanted inclusions. For the monitoring of the plasticizing process in the channels of the screw an ultrasonic pulse is transmitted into the barrel. By analyzing the reflected pulses it is possible to estimate solid bed and melt regions in the screw channel. The proposed systems were tested for accuracy and validity by simulations and test measurements.

  11. Bypassing the Limits of Ll Regularization: Convex Sparse Signal Processing Using Non-Convex Regularization

    Science.gov (United States)

    Parekh, Ankit

    Sparsity has become the basis of some important signal processing methods over the last ten years. Many signal processing problems (e.g., denoising, deconvolution, non-linear component analysis) can be expressed as inverse problems. Sparsity is invoked through the formulation of an inverse problem with suitably designed regularization terms. The regularization terms alone encode sparsity into the problem formulation. Often, the ℓ1 norm is used to induce sparsity, so much so that ℓ1 regularization is considered to be `modern least-squares'. The use of ℓ1 norm, as a sparsity-inducing regularizer, leads to a convex optimization problem, which has several benefits: the absence of extraneous local minima, well developed theory of globally convergent algorithms, even for large-scale problems. Convex regularization via the ℓ1 norm, however, tends to under-estimate the non-zero values of sparse signals. In order to estimate the non-zero values more accurately, non-convex regularization is often favored over convex regularization. However, non-convex regularization generally leads to non-convex optimization, which suffers from numerous issues: convergence may be guaranteed to only a stationary point, problem specific parameters may be difficult to set, and the solution is sensitive to the initialization of the algorithm. The first part of this thesis is aimed toward combining the benefits of non-convex regularization and convex optimization to estimate sparse signals more effectively. To this end, we propose to use parameterized non-convex regularizers with designated non-convexity and provide a range for the non-convex parameter so as to ensure that the objective function is strictly convex. By ensuring convexity of the objective function (sum of data-fidelity and non-convex regularizer), we can make use of a wide variety of convex optimization algorithms to obtain the unique global minimum reliably. The second part of this thesis proposes a non-linear signal

  12. 40 CFR Table 3 to Subpart Ddddd of... - Operating Limits for Boilers and Process Heaters With Mercury Emission Limits and Boilers and...

    Science.gov (United States)

    2010-07-01

    ... operating limits: If you demonstrate compliance with applicable mercury and/or total selected metals... applicable emission limits for mercury and/or total selected metals. 2. Fabric filter control a. Install and... applicable emission limits for mercury and/or total selected metals. 4. Dry scrubber or carbon injection...

  13. The effects of limited bandwidth and noise on verbal processing time and word recall in normal-hearing children.

    Science.gov (United States)

    McCreery, Ryan W; Stelmachowicz, Patricia G

    2013-09-01

    Understanding speech in acoustically degraded environments can place significant cognitive demands on school-age children who are developing the cognitive and linguistic skills needed to support this process. Previous studies suggest the speech understanding, word learning, and academic performance can be negatively impacted by background noise, but the effect of limited audibility on cognitive processes in children has not been directly studied. The aim of the present study was to evaluate the impact of limited audibility on speech understanding and working memory tasks in school-age children with normal hearing. Seventeen children with normal hearing between 6 and 12 years of age participated in the present study. Repetition of nonword consonant-vowel-consonant stimuli was measured under conditions with combinations of two different signal to noise ratios (SNRs; 3 and 9 dB) and two low-pass filter settings (3.2 and 5.6 kHz). Verbal processing time was calculated based on the time from the onset of the stimulus to the onset of the child's response. Monosyllabic word repetition and recall were also measured in conditions with a full bandwidth and 5.6 kHz low-pass cutoff. Nonword repetition scores decreased as audibility decreased. Verbal processing time increased as audibility decreased, consistent with predictions based on increased listening effort. Although monosyllabic word repetition did not vary between the full bandwidth and 5.6 kHz low-pass filter condition, recall was significantly poorer in the condition with limited bandwidth (low pass at 5.6 kHz). Age and expressive language scores predicted performance on word recall tasks, but did not predict nonword repetition accuracy or verbal processing time. Decreased audibility was associated with reduced accuracy for nonword repetition and increased verbal processing time in children with normal hearing. Deficits in free recall were observed even under conditions where word repetition was not affected

  14. Composition and redox control of waste glasses: Recommendation for process control limit

    International Nuclear Information System (INIS)

    Jantzen, C.M.; Plodinec, M.J.

    1986-01-01

    An electrochemical series of redox couples, originally developed for Savannah River Laboratory glass frit 131 (SRL-131) as a reference composition, has been extended to two other alkali borosilicate compositions that are candidate glasses for nuclear waste immobilization. Since no dramatic differences were ascertained in the redox chemistry of selected multivalent elements in SRL-131 versus that in Savannah River Laboratory glass frit 165 (SRL-165) and in West Valley glass number-sign 205 (WV-205), the comprehensive electrochemical series can readily be applied to a range of nuclear waste glass compositions. In order to alleviate potential problems with foaming and precipitation of insolubles during the processing of the nuclear waste in these glass melts, the [Fe 2+ ]/[Fe 3+ ] ratio of the melt should be between 0.1 and 0.5. 27 refs., 4 figs., 2 tabs

  15. Application limits of finite element models for simulation of shock transfer processes in concrete structures

    International Nuclear Information System (INIS)

    Krutzik, Norbert J.; Eibl, Josef

    2005-01-01

    Shocks on building structures due to impact loads (drop of wreckage and heavy masses from accidents, transport operations, explosions, etc.), especially in case of a postulated aircraft crash, may lead to feasibility problems due to high-induced vibrations and large expenditures at safety-related systems accommodated inside the building structures. A rational and cost-effective qualification of the functionality of such systems requires the prediction of reliable information about the nature of structural responses induced by impact loading in the corresponding regions of the structure. The analytic derivation of realistic and reliable structural responses requires the application of adequate mathematical models and methods as well as a critical evaluation of all factors that influence the entire shock transmission path, from the area of impact to the site of installation of the affected component or system in the structure. Despite extensive studies and computational analyses of impact-induced shocks performed using finite element simulation method, limited and insufficient experimental results to date have precluded a complete investigation and clarification of several 'peculiarities' in the field of shock transmission in finite element models. This refers mainly to the divergence of results observed using FE models when not considering a the required FE element discretization ratio as well as to the attenuation and scatter behavior of the dynamic response results obtained for large building structures and given large distances between the load impact application areas and the component anchoring locations. The cause for such divergences are related to several up to now not clarified 'phenomena' of FE models especially the low-pass filtering effects and dispersion characteristics of FE models

  16. Limitations of Feedback, Feedforward and IMC Controller for a First Order Non-Linear Process with Dead Time

    Directory of Open Access Journals (Sweden)

    Maruthai Suresh

    2010-10-01

    Full Text Available A nonlinear process, the heat exchanger whose parameters vary with respect to the process variable, is considered. The time constant and gain of the chosen process vary as a function of temperature. The limitations of the conventional feedback controller tuned using Ziegler-Nichols settings for the chosen process are brought out. The servo and regulatory responses through simulation and experimentation for various magnitudes of set-point changes and load changes at various operating points with the controller tuned only at a chosen nominal operating point are obtained and analyzed. Regulatory responses for output load changes are studied. The efficiency of feedforward controller and the effects of modeling error have been brought out. An IMC based system is presented to understand clearly how variations of system parameters affect the performance of the controller. The present work illustrates the effectiveness of Feedforward and IMC controller.

  17. Nutrient limitation on ecosystem productivity and processes of mature and old-growth subtropical forests in China.

    Directory of Open Access Journals (Sweden)

    Enqing Hou

    Full Text Available Nitrogen (N is considered the dominant limiting nutrient in temperate regions, while phosphorus (P limitation frequently occurs in tropical regions, but in subtropical regions nutrient limitation is poorly understood. In this study, we investigated N and P contents and N:P ratios of foliage, forest floors, fine roots and mineral soils, and their relationships with community biomass, litterfall C, N and P productions, forest floor turnover rate, and microbial processes in eight mature and old-growth subtropical forests (stand age >80 yr at Dinghushan Biosphere Reserve, China. Average N:P ratios (mass based in foliage, litter (L layer and mixture of fermentation and humus (F/H layer, and fine roots were 28.3, 42.3, 32.0 and 32.7, respectively. These values are higher than the critical N:P ratios for P limitation proposed (16-20 for foliage, ca. 25 for forest floors. The markedly high N:P ratios were mainly attributed to the high N concentrations of these plant materials. Community biomass, litterfall C, N and P productions, forest floor turnover rate and microbial properties were more strongly related to measures of P than N and frequently negatively related to the N:P ratios, suggesting a significant role of P availability in determining ecosystem production and productivity and nutrient cycling at all the study sites except for one prescribed disturbed site where N availability may also be important. We propose that N enrichment is probably a significant driver of the potential P limitation in the study area. Low P parent material may also contribute to the potential P limitation. In general, our results provided strong evidence supporting a significant role for P availability, rather than N availability, in determining ecosystem primary productivity and ecosystem processes in subtropical forests of China.

  18. Study of the $W^+ W^- \\gamma$ Process and Limits on Anomalous Quartic Gauge Boson Couplings at LEP

    CERN Document Server

    Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Buijs, A.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; van Dierendonck, D.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duinker, P.; Echenard, B.; Eline, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Ewers, A.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Krenz, W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Lubelsmeyer, K.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mangeol, D.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niessen, T.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Palomares, C.; Pandoulas, D.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofev, D.O.; Prokofiev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Sanders, M.P.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D.J.; Schwering, G.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Violini, P.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wallraff, W.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zoller, M.

    2002-01-01

    The process e+e- --> W+ W- \\gamma is studied using the data collected by the L3 detector at LEP. New results, corresponding to an integrated luminosity of 427.4 pb-1 at centre-of-mass energies from 192~GeV to 207~GeV, are presented. The W+W-\\gamma cross sections are measured to be in agreement with Standard Model expectations. No hints of anomalous quartic gauge boson couplings are observed. Limits at 95\\% confidence level are derived using also the process e+e- --> \

  19. LIMITED RUN PRODUCTION USING ALUMIDE® TOOLING FOR THE PLASTIC INJECTION MOULDING PROCESS#1

    Directory of Open Access Journals (Sweden)

    J. Combrinck

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Existing techniques for the production of conventional steel tooling for plastic injection moulding are expensive and time-consuming. As a result, many new products often do not advance beyond the prototype stage. This paper describes an investigation into the possibility of using laser sintered Alumide® (an aluminium-filled nylon material in a novel alternative process for producing hybrid rapid tooling tools. Initial experiments performed by researchers at the Central University of Technology have shown excellent results. An Alumide® tool can be manufactured in a shorter time and at a significantly lower cost than the same size direct metal laser sintered tool.

    AFRIKAANSE OPSOMMING: Bestaande tegnieke vir die vervaardiging van konvensionele staal gietstukke vir die plastiek spuit-giet proses is duur en tydrowend. Die gevolg hiervan is dat baie nuwe produkte nie verder as die prototipe stadium vorder nie. Hierdie artikel ondersoek die moontlikheid om laser gesinterde Alumide® (aluminium gevulde nylon materiaal in ’n nuwe benadering as ’n alternatiewe proses vir die vervaardiging van snel hibried-gietvorms te gebruik. Aanvanklike eksperimente uitgevoer deur navorsers aan die Sentrale Universiteit vir Tegnologie het uitstekende resultate gelewer. ’n Alumide® gietvorm kan vinniger en goedkoper vervaardig word as dieselfde grootte direk metaal gesinterde gietvorm.

  20. Modifications of alpha processing software to improve calculation of limits for qualitative detection

    Energy Technology Data Exchange (ETDEWEB)

    Kirkpatrick, J.R.

    1997-01-01

    The work described in this report was done for the Bioassay Counting Laboratory (BCL) of the Center of Excellence for Bioassay of the Analytical Services Organization at the Oak Ridge Y-12 Plant. BCL takes urine and fecal samples and tests for alpha radiation. An automated system, supplied by Canberra Industries, counts the activities in the samples and processes the results. The Canberra system includes hardware and software. The managers of BCL want to improve the accuracy of the results they report to their final customers. The desired improvements are of particular interest to the managers of BCL because the levels of alpha-emitting radionuclides in samples measured at BCL are usually so low that a significant fraction of the measured signal is due to background and to the reagent material used to extract the radioactive nuclides from the samples. Also, the background and reagent signals show a significant level of random variation. The customers at BCL requested four major modifications of the software. The requested software changes have been made and tested. The present report is in two parts. The first part describes what the modifications were supposed to accomplish. The second part describes the changes on a line-by-line basis. The second part includes listings of the changed software and discusses possible steps to correct a particular error condition. Last, the second part describes the effect of truncation errors on the standard deviations calculated from samples whose signals are very nearly the same.

  1. Modifications of alpha processing software to improve calculation of limits for qualitative detection

    International Nuclear Information System (INIS)

    Kirkpatrick, J.R.

    1997-01-01

    The work described in this report was done for the Bioassay Counting Laboratory (BCL) of the Center of Excellence for Bioassay of the Analytical Services Organization at the Oak Ridge Y-12 Plant. BCL takes urine and fecal samples and tests for alpha radiation. An automated system, supplied by Canberra Industries, counts the activities in the samples and processes the results. The Canberra system includes hardware and software. The managers of BCL want to improve the accuracy of the results they report to their final customers. The desired improvements are of particular interest to the managers of BCL because the levels of alpha-emitting radionuclides in samples measured at BCL are usually so low that a significant fraction of the measured signal is due to background and to the reagent material used to extract the radioactive nuclides from the samples. Also, the background and reagent signals show a significant level of random variation. The customers at BCL requested four major modifications of the software. The requested software changes have been made and tested. The present report is in two parts. The first part describes what the modifications were supposed to accomplish. The second part describes the changes on a line-by-line basis. The second part includes listings of the changed software and discusses possible steps to correct a particular error condition. Last, the second part describes the effect of truncation errors on the standard deviations calculated from samples whose signals are very nearly the same

  2. New Forming Limits For Light Alloys By Means Of Electromagnetic Forming And Numerical Simulation Of The Process

    International Nuclear Information System (INIS)

    Jimbert, P.; Fernandez, J. I.; Eguia, I.; Gutierrez, M.; Ulacia, I.; Hurtado, I.

    2007-01-01

    It is well known that one of the main advantages of the high speed forming (HSF) processes is the improvement in the forming limits of the used materials.Using the Electromagnetic Forming (EMF) technology two materials have been tested with different mechanical and physical properties: the AA5754 aluminium and the AZ31B magnesium alloys.The EMF process principle can be described as follows: A significant amount of electrical energy is stored in a bank of capacitors which are suddenly discharged releasing all the stored energy. This electric discharge runs through a coil which generates an intense transient magnetic field. At the same time transient Eddy currents are induced in the electrically conductive part placed some millimetres far from the coil. Another intense magnetic field is generated due to those Eddy currents but on the opposite direction as the one generated by the coil. A big magnetic repulsion force is created between the part and the coil. This magnetic repulsion between both fields is used to launch the blank with no physical contact and obtain the desired deformation on it.The Forming Limit Diagrams (FLD) obtained in the EMF experiments were them compared to the ones obtained with the 'Nakazima' method at conventional deformation speed for both alloys. In parallel to these physical experiments, some simulations were carried out. But trying to simulate this process by FEM is a though work. There are several physics and many factors to take into account in a few microseconds deformation process. And all these factors are tightly related with each other, that is why to this date there is no commercial software able to simulate the EMF process accurately.From LABEIN-Tecnalia we are working with to different softwares to simulate the whole process: Maxwell 3D for the electromagnetic part and PAM-STAMP2G for the mechanical part of the problem

  3. Study of the $e^+ e^- \\to Z \\gamma$ Process at LEP and Limits on Triple Neutral-Gauge-Boson Couplings

    CERN Document Server

    Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Dehmelt, K.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Duda, M.; Echenard, B.; Eline, A.; El Hage, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, M.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Nisati, A.; Novak, T.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Pal, I.; Palomares, C.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, Mohammad Azizur; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosemann, C.; Rosenbleck, C.; Rosier-Lees, S.; Roth, Stefan; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Schafer, C.; Schegelsky, V.; Schopper, H.; Schotanus, D.J.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Son, D.; Souga, C.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Vasquez, R.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wang, Q.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wilkens, H.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, An.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zimmermann, B.; Zoller, M.

    2004-01-01

    The process e^+e^- --> Z gamma, where the Z boson decays into hadrons or neutrinos, is studied with data collected with the L3 detector at LEP at centre-of-mass energies from 189 GeV up to 209 GeV. The cross sections are measured and found to be in agreement with the Standard Model predictions. Limits on triple neutral-gauge-boson couplings, forbidden in the Standard Model at tree level, are derived. Limits on the energy scales at which the anomalous couplings could be manifest are set. They range from 0.3 TeV to 2.3 TeV depending on the new physics effect under consideration.

  4. Relating belowground microbial composition to the taxonomic, phylogenetic, and functional trait distributions of trees in a tropical forest.

    Science.gov (United States)

    Barberán, Albert; McGuire, Krista L; Wolf, Jeffrey A; Jones, F Andrew; Wright, Stuart Joseph; Turner, Benjamin L; Essene, Adam; Hubbell, Stephen P; Faircloth, Brant C; Fierer, Noah

    2015-12-01

    The complexities of the relationships between plant and soil microbial communities remain unresolved. We determined the associations between plant aboveground and belowground (root) distributions and the communities of soil fungi and bacteria found across a diverse tropical forest plot. Soil microbial community composition was correlated with the taxonomic and phylogenetic structure of the aboveground plant assemblages even after controlling for differences in soil characteristics, but these relationships were stronger for fungi than for bacteria. In contrast to expectations, the species composition of roots in our soil core samples was a poor predictor of microbial community composition perhaps due to the patchy, ephemeral, and highly overlapping nature of fine root distributions. Our ability to predict soil microbial composition was not improved by incorporating information on plant functional traits suggesting that the most commonly measured plant traits are not particularly useful for predicting the plot-level variability in belowground microbial communities. © 2015 John Wiley & Sons Ltd/CNRS.

  5. UV-B-mediated changes on below-ground communities associated with the roots of Acer saccharum

    International Nuclear Information System (INIS)

    Klironomos, J.N.; Allen, M.F.

    1995-01-01

    1. Little is known about how exposure to UV-B radiation affects rhizosphere microbes. Rhizosphere organisms are fed primarily by root-derived substrates and fulfil functions such as mineralization, immobilization, decomposition, pathogeneity and improvement of plant nutrition; they form the base of the below-ground food web. 2. In this study, we exposed Sugar Maple (Acer saccharum) seedlings to UV-B radiation in order to determine if UV-B influences the activities of mycorrhizal and non-mycorrhizal fungi, bacteria and microbe-feeding arthropods in the rhizosphere. 3. Below-ground organisms are greatly affected by UV-B radiation. Overall, carbon-flow in the plant soil system was shifted from a mutualistic-closed, mycorrhizal-dominated system to an opportunist-open, saprobe/pathogen-dominated one. (author)

  6. 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

  7. Extending the process limits of laser polymer welding with high-brilliance beam sources (recent status and prospects of POLYBRIGHT)

    Science.gov (United States)

    Olowinsky, A.; Boglea, A.

    2011-03-01

    Plastics play an important role in almost every facet of our lives and constitute a wide variety of products, from everyday products such as food and beverage packaging, over furniture and building materials to high tech products in the automotive, electronics, aerospace, white goods, medical and other sectors [1]. The objective of PolyBright, the European Research project on laser polymer welding, is to provide high speed and flexible laser manufacturing technology and expand the limits of current plastic part assembly. New laser polymer joining processes for optimized thermal management in combination with adapted wavelengths will provide higher quality, high processing speed up to 1 m/s and robust manufacturing processes at lower costs. Key innovations of the PolyBright project are fibre lasers with high powers up to 500 W, high speed scanning and flexible beam manipulation systems for simultaneous welding and high-resolution welding, such as dynamic masks and multi kHz scanning heads. With this initial step, PolyBright will break new paths in processing of advanced plastic products overcoming the quality and speed limitations of conventional plastic part assembly. Completely new concepts for high speed processing, flexibility and quality need to be established in combination with high brilliance lasers and related equipment. PolyBright will thus open new markets for laser systems with a short term potential of over several 100 laser installations per year and a future much larger market share in the still growing plastic market. PolyBright will hence establish a comprehensive and sustainable development activity on new high brilliance lasers that will strengthen the laser system industry.

  8. Impacts of Jatropha-based biodiesel production on above and below-ground carbon stocks: A case study from Mozambique

    International Nuclear Information System (INIS)

    Vang Rasmussen, Laura; Rasmussen, Kjeld; Bech Bruun, Thilde

    2012-01-01

    The need to mitigate climate change makes production of liquid biofuels a high priority. Substituting fossil fuels by biodiesel produced from Jatropha curcas has gained widespread attention as Jatropha cultivation is claimed to offer green house gas emission reductions. Farmers respond worldwide to this increasing demand by converting forests into Jatropha, but whether Jatropha-based biodiesel offers carbon savings depends on the carbon emissions that occur when land use is changed to Jatropha. This paper provides an impact assessment of a small-scale Jatropha project in Cabo Delgado, Mozambique. The paper outlines the estimated impacts on above and below-ground carbon stocks when land use is changed to increase Jatropha production. The results show that expansion of Jatropha production will most likely lead to the conversion of miombo forest areas to Jatropha, which implies a reduction in above and below-ground carbon stocks. The carbon debts created by the land use change can be repaid by replacing fossil fuels with Jatropha-based biodiesel. A repayment time of almost two centuries is found with optimistic estimates of the carbon debt, while the use of pessimistic values results in a repayment time that approaches the millennium. - Highlights: ► Demands for biofuels make production of Jatropha-based biodiesel a priority. ► Farmers in Northern Mozambique are likely to convert un-logged miombo to Jatropha. ► Converting miombo to Jatropha creates reductions in above and below-ground carbon. ► It takes 187–966 years to repay emissions from above and below-ground carbon stocks.

  9. A hybrid model for mapping relative differences in belowground biomass and root: Shoot ratios using spectral reflectance, foliar N and plant biophysical data within coastal marsh

    Science.gov (United States)

    Jessica L. O'Connell,; Byrd, Kristin B.; Maggi Kelly,

    2015-01-01

    Broad-scale estimates of belowground biomass are needed to understand wetland resiliency and C and N cycling, but these estimates are difficult to obtain because root:shoot ratios vary considerably both within and between species. We used remotely-sensed estimates of two aboveground plant characteristics, aboveground biomass and % foliar N to explore biomass allocation in low diversity freshwater impounded peatlands (Sacramento-San Joaquin River Delta, CA, USA). We developed a hybrid modeling approach to relate remotely-sensed estimates of % foliar N (a surrogate for environmental N and plant available nutrients) and aboveground biomass to field-measured belowground biomass for species specific and mixed species models. We estimated up to 90% of variation in foliar N concentration using partial least squares (PLS) regression of full-spectrum field spectrometer reflectance data. Landsat 7 reflectance data explained up to 70% of % foliar N and 67% of aboveground biomass. Spectrally estimated foliar N or aboveground biomass had negative relationships with belowground biomass and root:shoot ratio in both Schoenoplectus acutus and Typha, consistent with a balanced growth model, which suggests plants only allocate growth belowground when additional nutrients are necessary to support shoot development. Hybrid models explained up to 76% of variation in belowground biomass and 86% of variation in root:shoot ratio. Our modeling approach provides a method for developing maps of spatial variation in wetland belowground biomass.

  10. Observations on the perspectives and limits of the evidence-based approach in the evaluation of gamification processes

    Directory of Open Access Journals (Sweden)

    Bruni Filippo

    2015-12-01

    Full Text Available As continually greater attention is given to the processes of gamification, the dimension pertaining to evaluation must also be focussed on the purpose of avoiding ineffective forms of banalisation. In reference to the evidence-based approach proposed by Mayer and in highlighting its possibilities and limits, an experiment is herein presented related to teacher training, in which we attempt to unite some traits of the processes of gamification to a first evaluation screen. The data obtained, if they seem on the one hand, indicate an overall positive perception on the part of the attendees, on the other though, they indicate forms of resistance and of saturation with respect to both the excessively competitive mechanisms and the peer evaluation procedures.

  11. Costs of jasmonic acid induced defense in aboveground and belowground parts of corn (Zea mays L.).

    Science.gov (United States)

    Feng, Yuanjiao; Wang, Jianwu; Luo, Shiming; Fan, Huizhi; Jin, Qiong

    2012-08-01

    Costs of jasmonic acid (JA) induced plant defense have gained increasing attention. In this study, JA was applied continuously to the aboveground (AG) or belowground (BG) parts, or AG plus BG parts of corn (Zea mays L.) to investigate whether JA exposure in one part of the plant would affect defense responses in another part, and whether or not JA induced defense would incur allocation costs. The results indicated that continuous JA application to AG parts systemically affected the quantities of defense chemicals in the roots, and vice versa. Quantities of DIMBOA and total amounts of phenolic compounds in leaves or roots generally increased 2 or 4 wk after the JA treatment to different plant parts. In the first 2 wk after application, the increase of defense chemicals in leaves and roots was accompanied by a significant decrease of root length, root surface area, and root biomass. Four weeks after the JA application, however, no such costs for the increase of defense chemicals in leaves and roots were detected. Instead, shoot biomass and root biomass increased. The results suggest that JA as a defense signal can be transferred from AG parts to BG parts of corn, and vice versa. Costs for induced defense elicited by continuous JA application were found in the early 2 wk, while distinct benefits were observed later, i.e., 4 wk after JA treatment.

  12. Above- and Belowground Biomass Models for Trees in the Miombo Woodlands of Malawi

    Directory of Open Access Journals (Sweden)

    Daud J. Kachamba

    2016-02-01

    Full Text Available In this study we present general (multiple tree species from several sites above- and belowground biomass models for trees in the miombo woodlands of Malawi. Such models are currently lacking in the country. The modelling was based on 74 trees comprising 33 different species with diameters at breast height (dbh and total tree height (ht ranging from 5.3 to 2 cm and from 3.0 to 25.0 m, respectively. Trees were collected from four silvicultural zones covering a wide range of conditions. We tested different models including dbh, ht and wood specific gravity ( ρ as independent variables. We evaluated model performance using pseudo-R2, root mean square error (RMSE, a covariance matrix for the parameter estimates, mean prediction error (MPE and relative mean prediction error (MPE%. Computation of MPE% was based on leave-one-out cross-validation. Values of pseudo-R2 and MPE% ranged 0.82–0.97 and 0.9%–2.8%, respectively. Model performance indicated that the models can be used over a wide range of geographical and ecological conditions in Malawi.

  13. Plant genotypes affect aboveground and belowground herbivore interactions by changing chemical defense.

    Science.gov (United States)

    Li, Xiaoqiong; Guo, Wenfeng; Siemann, Evan; Wen, Yuanguang; Huang, Wei; Ding, Jianqing

    2016-12-01

    Spatially separated aboveground (AG) and belowground (BG) herbivores are closely linked through shared host plants, and both patterns of AG-BG interactions and plant responses may vary among plant genotypes. We subjected invasive (USA) and native (China) genotypes of tallow tree (Triadica sebifera) to herbivory by the AG specialist leaf-rolling weevil Heterapoderopsis bicallosicollis and/or the root-feeding larvae of flea beetle Bikasha collaris. We measured leaf damage and leaves rolled by weevils, quantified beetle survival, and analyzed flavonoid and tannin concentrations in leaves and roots. AG and BG herbivores formed negative feedbacks on both native and invasive genotypes. Leaf damage by weevils and the number of beetle larvae emerging as adults were higher on invasive genotypes. Beetles reduced weevil damage and weevils reduced beetle larval emergence more strongly for invasive genotypes. Invasive genotypes had lower leaf and root tannins than native genotypes. BG beetles decreased leaf tannins of native genotypes but increased root tannins of invasive genotypes. AG herbivory increased root flavonoids of invasive genotypes while BG herbivory decreased leaf flavonoids. Invasive genotypes had lower AG and BG herbivore resistance, and negative AG-BG herbivore feedbacks were much stronger for invasive genotypes. Lower tannin concentrations explained overall better AG and BG herbivore performances on invasive genotypes. However, changes in tannins and flavonoids affected AG and BG herbivores differently. These results suggest that divergent selection on chemical production in invasive plants may be critical in regulating herbivore performances and novel AG and BG herbivore communities in new environments.

  14. Picturing Adoption of Below-Ground Biodiversity Technologies among Smallholder Farmers around Mabira Forest, Uganda

    Directory of Open Access Journals (Sweden)

    Isabirye, BE.

    2010-01-01

    Full Text Available Faced with a multitude of soil and water amendment technologies, farmers have the task of choosing the technologies to adopt for ensuring subsistence and income sustainability. In 2008, a study to characterize the farmers was conducted around Mabira Forest, to assess the adoption of soil technologies fostering Belowground Biodiversity (BGBD. Eighty-four households (38 participating and 46 non-participants from four villages were randomly selected and interviewed. Results showed that the adoption pattern was significantly driven by farm size, labor, household size, age and wealth status of the house. Also important were farm location, gender of household head, primary occupation, soil and water conservation technologies training, land tenure, and social capital. For the few current adopters, there was a perceived increase in labor demand but overall productivity was higher, partly resulting from increased crop productivity due to soil fertility enhancement and soil structure modification. It is therefore concluded that, around Mabira forest, BGBD technologies will be adopted by farming households with sufficient land, labor and social capital.

  15. Aboveground endophyte affects root volatile emission and host plant selection of a belowground insect.

    Science.gov (United States)

    Rostás, Michael; Cripps, Michael G; Silcock, Patrick

    2015-02-01

    Plants emit specific blends of volatile organic compounds (VOCs) that serve as multitrophic, multifunctional signals. Fungi colonizing aboveground (AG) or belowground (BG) plant structures can modify VOC patterns, thereby altering the information content for AG insects. Whether AG microbes affect the emission of root volatiles and thus influence soil insect behaviour is unknown. The endophytic fungus Neotyphodium uncinatum colonizes the aerial parts of the grass hybrid Festuca pratensis × Lolium perenne and is responsible for the presence of insect-toxic loline alkaloids in shoots and roots. We investigated whether endophyte symbiosis had an effect on the volatile emission of grass roots and if the root herbivore Costelytra zealandica was able to recognize endophyte-infected plants by olfaction. In BG olfactometer assays, larvae of C. zealandica were more strongly attracted to roots of uninfected than endophyte-harbouring grasses. Combined gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry revealed that endophyte-infected roots emitted less VOCs and more CO2. Our results demonstrate that symbiotic fungi in plants may influence soil insect distribution by changing their behaviour towards root volatiles. The well-known defensive mutualism between grasses and Neotyphodium endophytes could thus go beyond bioactive alkaloids and also confer protection by being chemically less apparent for soil herbivores.

  16. Plant species distribution along environmental gradient: do belowground interactions with fungi matter?

    Directory of Open Access Journals (Sweden)

    Loïc ePellissier

    2013-12-01

    Full Text Available The distribution of plants along environmental gradients is constrained by abiotic and biotic factors. Cumulative evidence attests of the impact of abiotic factors on plant distributions, but only few studies discuss the role of belowground communities. Soil fungi, in particular, are thought to play an important role in how plant species assemble locally into communities. We first review existing evidence, and then test the effect of the number of soil fungal operational taxonomic units (OTUs on plant species distributions using a recently collected dataset of plant and metagenomic information on soil fungi in the Western Swiss Alps. Using species distribution models, we investigated whether the distribution of individual plant species is correlated to the number of OTUs of two important soil fungal classes known to interact with plants: the Glomeromycetes, that are obligatory symbionts of plants, and the Agaricomycetes, that may be facultative plant symbionts, pathogens, or wood decayers. We show that including the fungal richness information in the models of plant species distributions improves predictive accuracy. Number of fungal OTUs is especially correlated to the distribution of high elevation plant species. We suggest that high elevation soil show greater variation in fungal assemblages that may in turn impact plant turnover among communities. We finally discuss how to move beyond correlative analyses, through the design of field experiments manipulating plant and fungal communities along environmental gradients.

  17. Modeling persistence of motion in a crowded environment: The diffusive limit of excluding velocity-jump processes

    Science.gov (United States)

    Gavagnin, Enrico; Yates, Christian A.

    2018-03-01

    Persistence of motion is the tendency of an object to maintain motion in a direction for short time scales without necessarily being biased in any direction in the long term. One of the most appropriate mathematical tools to study this behavior is an agent-based velocity-jump process. In the absence of agent-agent interaction, the mean-field continuum limit of the agent-based model (ABM) gives rise to the well known hyperbolic telegraph equation. When agent-agent interaction is included in the ABM, a strictly advective system of partial differential equations (PDEs) can be derived at the population level. However, no diffusive limit of the ABM has been obtained from such a model. Connecting the microscopic behavior of the ABM to a diffusive macroscopic description is desirable, since it allows the exploration of a wider range of scenarios and establishes a direct connection with commonly used statistical tools of movement analysis. In order to connect the ABM at the population level to a diffusive PDE at the population level, we consider a generalization of the agent-based velocity-jump process on a two-dimensional lattice with three forms of agent interaction. This generalization allows us to take a diffusive limit and obtain a faithful population-level description. We investigate the properties of the model at both the individual and population levels and we elucidate some of the models' key characteristic features. In particular, we show an intrinsic anisotropy inherent to the models and we find evidence of a spontaneous form of aggregation at both the micro- and macroscales.

  18. Parameter estimation and long-term process simulation of a biogas reactor operated under trace elements limitation

    International Nuclear Information System (INIS)

    Lübken, Manfred; Koch, Konrad; Gehring, Tito; Horn, Harald; Wichern, Marc

    2015-01-01

    Highlights: • Estimation of ADM1 parameter uncertainty by nonlinear, correlated parameter analysis. • Unbounded confidence regions were obtained for single hydrolysis rate constants. • ADM1 carbohydrates were divided into a slowly and readily degradable part. • Bioavailability of trace metals explained discrepancies between modeled and measured data. - Abstract: The Anaerobic Digestion Model No. 1 (ADM1) was modified to describe the long-term process stability of a two-stage agricultural biogas system operated for 494 days with a mono-substrate. The ADM1 model fraction for carbohydrates was divided into a slowly and readily degradable part. Significant different hydrolysis rate constants were found for proteins and single fractions of carbohydrates in batch experiments. Degradation of starch, xylan (hemicellulose), cellulose and zein (protein) were modeled with first order hydrolysis rate coefficients of 1.20 d −1 , 0.70 d −1 , 0.18 d −1 and 0.30 d −1 , respectively. While the hydrolysis rate coefficients found in batch experiments could be used for predicting continuous process data, the statistically calculated confidence regions (nonlinear parameter estimation) showed that the upper limits were unbounded. Single discrepancies between measured and modeled process data of the two-stage pilot system could be explained by the lack of bioavailability of trace elements. Addition of iron, as Fe(III)Cl 3 , allowed stable process conditions for an organic loading rate (OLR) up to 2.5 g VS L −1 d −1 . Additional supplement of trace elements was necessary for process operation at OLRs above 2.5 g VS L −1 d −1

  19. Materials and process limitations for thermoplastic composite materials for wind turbine blades - preform of prepregs and commingled yarns

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, R.T.D.

    2011-07-01

    Wind turbine blades are produced based on the current thermoset resin technology, but thermoplastics can offer better potential to become the future blade materials. One of the most important goals when designing larger blade systems is to keep the blade weight under control. Thermoplastic materials offer weight saving similar to thermosets, apart from many other benefits like design flexibility, durability, cost, weight saving, and performance advantageous to the wind industry. In the current research study a detailed discussion on material and process limitations such as thermoplastic prepreg tapes and commingled yams are presented in terms of their properties and available forms in the current markets. A critical review of thermoplastics discussed in the context of turbine blades applications. (Author)

  20. Limits, discovery and cut optimization for a Poisson process with uncertainty in background and signal efficiency: TRolke 2.0

    Science.gov (United States)

    Lundberg, J.; Conrad, J.; Rolke, W.; Lopez, A.

    2010-03-01

    A C++ class was written for the calculation of frequentist confidence intervals using the profile likelihood method. Seven combinations of Binomial, Gaussian, Poissonian and Binomial uncertainties are implemented. The package provides routines for the calculation of upper and lower limits, sensitivity and related properties. It also supports hypothesis tests which take uncertainties into account. It can be used in compiled C++ code, in Python or interactively via the ROOT analysis framework. Program summaryProgram title: TRolke version 2.0 Catalogue identifier: AEFT_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFT_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: MIT license No. of lines in distributed program, including test data, etc.: 3431 No. of bytes in distributed program, including test data, etc.: 21 789 Distribution format: tar.gz Programming language: ISO C++. Computer: Unix, GNU/Linux, Mac. Operating system: Linux 2.6 (Scientific Linux 4 and 5, Ubuntu 8.10), Darwin 9.0 (Mac-OS X 10.5.8). RAM:˜20 MB Classification: 14.13. External routines: ROOT ( http://root.cern.ch/drupal/) Nature of problem: The problem is to calculate a frequentist confidence interval on the parameter of a Poisson process with statistical or systematic uncertainties in signal efficiency or background. Solution method: Profile likelihood method, Analytical Running time:<10 seconds per extracted limit.

  1. Matrix density alters zyxin phosphorylation, which limits peripheral process formation and extension in endothelial cells invading 3D collagen matrices.

    Science.gov (United States)

    Abbey, Colette A; Bayless, Kayla J

    2014-09-01

    integrate signals from multiple exogenous factors, including changes in matrix density, to accomplish successful sprouting responses. We show here for the first time that zyxin limited the formation and extension of fine peripheral processes used by ECs for matrix interrogation, providing a molecular explanation for altered EC responses to high and low density collagen matrices. Copyright © 2014 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

  2. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Science.gov (United States)

    Vannette, Rachel L.; Hunter, Mark D.; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)—which all produce toxic cardenolides—with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

  3. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

    Science.gov (United States)

    Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense.

  4. Environmental Metabarcoding Reveals Contrasting Belowground and Aboveground Fungal Communities from Poplar at a Hg Phytomanagement Site.

    Science.gov (United States)

    Durand, Alexis; Maillard, François; Foulon, Julie; Gweon, Hyun S; Valot, Benoit; Chalot, Michel

    2017-11-01

    Characterization of microbial communities in stressful conditions at a field level is rather scarce, especially when considering fungal communities from aboveground habitats. We aimed at characterizing fungal communities from different poplar habitats at a Hg-contaminated phytomanagement site by using Illumina-based sequencing, network analysis approach, and direct isolation of Hg-resistant fungal strains. The highest diversity estimated by the Shannon index was found for soil communities, which was negatively affected by soil Hg concentration. Among the significant correlations between soil operational taxonomic units (OTUs) in the co-occurrence network, 80% were negatively correlated revealing dominance of a pattern of mutual exclusion. The fungal communities associated with Populus roots mostly consisted of OTUs from the symbiotic guild, such as members of the Thelephoraceae, thus explaining the lowest diversity found for root communities. Additionally, root communities showed the highest network connectivity index, while rarely detected OTUs from the Glomeromycetes may have a central role in the root network. Unexpectedly high richness and diversity were found for aboveground habitats, compared to the root habitat. The aboveground habitats were dominated by yeasts from the Lalaria, Davidiella, and Bensingtonia genera, not detected in belowground habitats. Leaf and stem habitats were characterized by few dominant OTUs such as those from the Dothideomycete class producing mutual exclusion with other OTUs. Aureobasidium pullulans, one of the dominating OTUs, was further isolated from the leaf habitat, in addition to Nakazawaea populi species, which were found to be Hg resistant. Altogether, these findings will provide an improved point of reference for microbial research on inoculation-based programs of tailings dumps.

  5. Mapping Above- and Below-Ground Carbon Pools in Boreal Forests: The Case for Airborne Lidar.

    Science.gov (United States)

    Kristensen, Terje; Næsset, Erik; Ohlson, Mikael; Bolstad, Paul V; Kolka, Randall

    2015-01-01

    A large and growing body of evidence has demonstrated that airborne scanning light detection and ranging (lidar) systems can be an effective tool in measuring and monitoring above-ground forest tree biomass. However, the potential of lidar as an all-round tool for assisting in assessment of carbon (C) stocks in soil and non-tree vegetation components of the forest ecosystem has been given much less attention. Here we combine the use airborne small footprint scanning lidar with fine-scale spatial C data relating to vegetation and the soil surface to describe and contrast the size and spatial distribution of C pools within and among multilayered Norway spruce (Picea abies) stands. Predictor variables from lidar derived metrics delivered precise models of above- and below-ground tree C, which comprised the largest C pool in our study stands. We also found evidence that lidar canopy data correlated well with the variation in field layer C stock, consisting mainly of ericaceous dwarf shrubs and herbaceous plants. However, lidar metrics derived directly from understory echoes did not yield significant models. Furthermore, our results indicate that the variation in both the mosses and soil organic layer C stock plots appears less influenced by differences in stand structure properties than topographical gradients. By using topographical models from lidar ground returns we were able to establish a strong correlation between lidar data and the organic layer C stock at a stand level. Increasing the topographical resolution from plot averages (~2000 m2) towards individual grid cells (1 m2) did not yield consistent models. Our study demonstrates a connection between the size and distribution of different forest C pools and models derived from airborne lidar data, providing a foundation for future research concerning the use of lidar for assessing and monitoring boreal forest C.

  6. The impacts of climate change and belowground herbivory on aphids via primary metabolites

    Science.gov (United States)

    Ryalls, James M. W.

    CO2 and simulated root damage on aphids could be explained by changes in plant amino acid concentrations. Chapter five built on the mechanistic findings from chapter four to determine whether specific groups of amino acids were responsible for driving the effects of eT and eCO2 on aphid fecundity, longevity and intrinsic rate of increase (rm). Chapter six extended this research to the field to determine the plant-mediated effects of water stress and root herbivory on aphids in a mixed grass-legume system. Lucerne demonstrated an over compensatory growth response to root herbivory by S. discoideus larvae by increasing net root biomass and nodulation by 31% and 45%, respectively. eT negated the positive effects of eCO2 on weevil larval development, as well as on a number of lucerne characteristics (e.g. nodulation and amino acid concentrations) and aphid performance parameters (e.g. population growth, fecundity and rm). Root herbivory by S. discoideus negatively impacted aphids in general, although effects were dependent on feeding duration and herbivore arrival sequence (i.e. whether aphids fed on the plant before or after root herbivory). While drought negatively impacted aphid abundance, potentially via reduced phloem turgor and sap viscosity, the effects of eT, eCO2 and root herbivory on aphids were often driven by concentrations of specific amino acid groups. Nitrogen (N) leached from lacerated lucerne root nodules by S. discoideus led to increased concentrations of N in a neighbouring grass, Phalaris aquatica (Poaceae), with knock-on effects on plant competition and community dynamics. The opposing effects of eT and eCO2 on plant characteristics and both aboveground and belowground herbivores demonstrates the importance of combining trophic complexity with multiple climatic factors as a means of gaining realistic insights into how insect and plant communities will respond under future conditions. Identifying the specific amino acid changes underpinning aphid

  7. Co-digestion of sewage sludge and sterilized solid slaughterhouse waste: methane production efficiency and process limitations.

    Science.gov (United States)

    Pitk, Peep; Kaparaju, Prasad; Palatsi, Jordi; Affes, Rim; Vilu, Raivo

    2013-04-01

    The rendering product of Category 2 and 3 Animal By-Products is known as sterilized mass (SM) and it is mainly composed of fat and proteins, making it interesting substrate for anaerobic digestion. Batch and semi-continuous laboratory experiments were carried out to investigate the effect of SM addition in co-digestion with sewage sludge on methane production and possible process limitations. Results showed that SM addition in the feed mixture up to 5% (w/w), corresponding to 68.1% of the organic loading, increased methane production 5.7 times, without any indication of process inhibition. Further increase of SM addition at 7.5% (w/w) caused methane production decrease and volatile solids removal reduction, that was mainly related to remarkably increased free ammonia concentration in the digester of 596.5±68.6 gNH3 L(-1). Sterilized mass addition of 10% (w/w) caused intensive foaming, LCFA accumulation of 9172±701.2 mgCOD-LCFA g(-1) sample and termination of the experiment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. A quality improvement project using statistical process control methods for type 2 diabetes control in a resource-limited setting.

    Science.gov (United States)

    Flood, David; Douglas, Kate; Goldberg, Vera; Martinez, Boris; Garcia, Pablo; Arbour, MaryCatherine; Rohloff, Peter

    2017-08-01

    Quality improvement (QI) is a key strategy for improving diabetes care in low- and middle-income countries (LMICs). This study reports on a diabetes QI project in rural Guatemala whose primary aim was to improve glycemic control of a panel of adult diabetes patients. Formative research suggested multiple areas for programmatic improvement in ambulatory diabetes care. This project utilized the Model for Improvement and Agile Global Health, our organization's complementary healthcare implementation framework. A bundle of improvement activities were implemented at the home, clinic and institutional level. Control charts of mean hemoglobin A1C (HbA1C) and proportion of patients meeting target HbA1C showed improvement as special cause variation was identified 3 months after the intervention began. Control charts for secondary process measures offered insights into the value of different components of the intervention. Intensity of home-based diabetes education emerged as an important driver of panel glycemic control. Diabetes QI work is feasible in resource-limited settings in LMICs and can improve glycemic control. Statistical process control charts are a promising methodology for use with panels or registries of diabetes patients. © The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  9. Estimating belowground carbon stocks in isolated wetlands of the Northern Everglades Watershed, central Florida, using ground penetrating radar (GPR) and aerial imagery

    Science.gov (United States)

    McClellan, Matthew; Comas, Xavier; Hinkle, Ross; Sumner, David M.

    2017-01-01

    Peat soils store a large fraction of the global soil carbon (C) pool and comprise 95% of wetland C stocks. While isolated freshwater wetlands in temperate and tropical biomes account for more than 20% of the global peatland C stock, most studies of wetland soil C have occurred in expansive peatlands in northern boreal and subarctic biomes. Furthermore, the contribution of small depressional wetlands in comparison to larger wetland systems in these environments is very uncertain. Given the fact that these wetlands are numerous and variable in terms of their internal geometry, innovative methods are needed for properly estimating belowground C stocks and their overall C contribution to the landscape. In this study, we use a combination of ground penetrating radar (GPR), aerial imagery, and direct measurements (coring) in conjunction with C core analysis to develop a relation between C stock and surface area, and estimate the contribution of subtropical depressional wetlands to the total C stock of pine flatwoods at the Disney Wilderness Preserve (DWP), Florida. Additionally, GPR surveys were able to image collapse structures underneath the peat basin of depressional wetlands, depicting lithological controls on the formation of depressional wetlands at the DWP. Results indicate the importance of depressional wetlands as critical contributors to the landscape C budget at the DWP and the potential of GPR-based approaches for (1) rapidly and noninvasively estimating the contribution of depressional wetlands to regional C stocks and (2) evaluating the formational processes of depressional wetlands.

  10. Estimating Belowground Carbon Stocks in Isolated Wetlands of the Northern Everglades Watershed, Central Florida, Using Ground Penetrating Radar and Aerial Imagery

    Science.gov (United States)

    McClellan, Matthew; Comas, Xavier; Benscoter, Brian; Hinkle, Ross; Sumner, David

    2017-11-01

    Peat soils store a large fraction of the global soil carbon (C) pool and comprise 95% of wetland C stocks. While isolated freshwater wetlands in temperate and tropical biomes account for more than 20% of the global peatland C stock, most studies of wetland soil C have occurred in expansive peatlands in northern boreal and subarctic biomes. Furthermore, the contribution of small depressional wetlands in comparison to larger wetland systems in these environments is very uncertain. Given the fact that these wetlands are numerous and variable in terms of their internal geometry, innovative methods are needed for properly estimating belowground C stocks and their overall C contribution to the landscape. In this study, we use a combination of ground penetrating radar (GPR), aerial imagery, and direct measurements (coring) in conjunction with C core analysis to develop a relation between C stock and surface area, and estimate the contribution of subtropical depressional wetlands to the total C stock of pine flatwoods at the Disney Wilderness Preserve (DWP), Florida. Additionally, GPR surveys were able to image collapse structures underneath the peat basin of depressional wetlands, depicting lithological controls on the formation of depressional wetlands at the DWP. Results indicate the importance of depressional wetlands as critical contributors to the landscape C budget at the DWP and the potential of GPR-based approaches for (1) rapidly and noninvasively estimating the contribution of depressional wetlands to regional C stocks and (2) evaluating the formational processes of depressional wetlands.

  11. Beyond the futility argument: the fair process approach and time-limited trials for managing dialysis conflict.

    Science.gov (United States)

    Rinehart, Ann

    2013-11-01

    Futility is an ancient concept arising from Greek mythology that was resurrected for its medical application in the 1980s with the proliferation of many lifesaving technologies, including dialysis and renal transplantation. By that time, the domineering medical paternalism that characterized the pre-1960s physician-patient relationship morphed into assertive patient autonomy, and some patients began to claim the right to demand aggressive, high-technology interventions, despite physician disapproval. To counter this power struggle, the establishment of a precise definition of futility offered hope for a futility policy that would allow physicians to justify withholding or withdrawing treatment, despite patient and family objections. This article reviews the various attempts made to define medical futility and describes their limited applicability to dialysis. When futility concerns arise, physicians should recognize the opportunity to address conflict, using best practice communication skills. Physicians would also benefit from understanding the ethical principles of respect for patient autonomy, beneficence, nonmaleficence, justice, and professional integrity that underlie medical decision-making. Also reviewed is the use of a fair process approach or time-limited trial when conflict resolution cannot be achieved. These topics are addressed in the Renal Physician Association's clinical practice guideline Shared Decision-Making in the Appropriate Initiation and Withdrawal from Dialysis, with which nephrologists should be well versed. A case presentation of intractable calciphylaxis in a new dialysis patient illustrates the pitfalls of physicians not fully appreciating the ethics of medical decision-making and failing to use effective conflict management approaches in the clinical practice guideline.

  12. Beyond the Futility Argument: The Fair Process Approach and Time-Limited Trials for Managing Dialysis Conflict

    Science.gov (United States)

    2013-01-01

    Summary Futility is an ancient concept arising from Greek mythology that was resurrected for its medical application in the 1980s with the proliferation of many lifesaving technologies, including dialysis and renal transplantation. By that time, the domineering medical paternalism that characterized the pre-1960s physician–patient relationship morphed into assertive patient autonomy, and some patients began to claim the right to demand aggressive, high-technology interventions, despite physician disapproval. To counter this power struggle, the establishment of a precise definition of futility offered hope for a futility policy that would allow physicians to justify withholding or withdrawing treatment, despite patient and family objections. This article reviews the various attempts made to define medical futility and describes their limited applicability to dialysis. When futility concerns arise, physicians should recognize the opportunity to address conflict, using best practice communication skills. Physicians would also benefit from understanding the ethical principles of respect for patient autonomy, beneficence, nonmaleficence, justice, and professional integrity that underlie medical decision-making. Also reviewed is the use of a fair process approach or time-limited trial when conflict resolution cannot be achieved. These topics are addressed in the Renal Physician Association’s clinical practice guideline Shared Decision-Making in the Appropriate Initiation and Withdrawal from Dialysis, with which nephrologists should be well versed. A case presentation of intractable calciphylaxis in a new dialysis patient illustrates the pitfalls of physicians not fully appreciating the ethics of medical decision-making and failing to use effective conflict management approaches in the clinical practice guideline. PMID:23868900

  13. Efficiency-limiting processes in OPV bulk heterojunctions of GeNIDTBT and IDT-based acceptors

    KAUST Repository

    Al-Saggaf, Sarah M.

    2018-05-16

    The successful realization of highly efficient bulk heterojunction OPV devices requires the development of organic donor and acceptor materials with tailored properties. Recently, non-fullerene acceptors (NFAs) have emerged as an alternative to the ubiquitously used fullerene derivatives. NFAs showed a rapid increase in efficiencies, now exceeding a PCE of 13%. In my thesis research, I used two small molecule IDT-based acceptors, namely O-IDTBR and O-IDTBCN, in combination with a wide bandgap donor polymer, GeNIDT-BT, as active material in BHJ solar cells and investigated their photophysical characteristics. The polymer combined with O-IDTBR as acceptor achieved a power conversion efficiency of only 2%, which is significantly lower than that obtained for the system of GeNIDT-BT: O-IDTBCN (5.3%). Using nano- to microsecond transient absorption spectroscopy, I investigated both systems and demonstrated that GeNIDT-BT:O-IDTBR exhibits more geminate recombination of interfacial charge-transfer states, leading to lower short circuit currents. Using time-delayed collection field experiments, I studied the field dependence of charge generation and its impact on the device fill factor. Overall, my results provide a qualitative understanding of the efficiency-limiting processes in both systems and their impact on device performance.

  14. Dominant acceleration processes of ambient energetic protons (E>= 50 keV) at the bow shock: conditions and limitations

    International Nuclear Information System (INIS)

    Anagnostopoulos, G.C.; Sarris, E.T.

    1983-01-01

    Energetic proton (Esub(p)>= 50 keV) and magnetic field observations during crossings of the Earth's Bow Shock by the IMP-7 and 8 spacecraft are incorporated in this work in order to examine the effect of the Bow Shock on a pre-existing proton population under different ''interplanetary magnetic field-Bow Shock'' configurations, as well as the conditions for the presence of the Bow Shock associated energetic proton intensity enhancements. The presented observations indicate that the dominant process for the efficient acceleration of ambient energetic particles to energies exceeding approximately 50 keV is by ''gradient-B'' drifting parallel to the induced electric field at quasi-perpendicular Bow Shocks under certain well defined limitations deriving from the finite and curved Bow Shock surface. It is shown that the proton acceleration at the Bow Shock is most efficient for high values of the upstream magnetic field (in general B 1 > 8#betta#), high upstream plasma speed and expanded Bow Shock fronts, as well as for direction of the induced electric field oriented almost parallel to the flanks of the Bow Shock, i.e. when the drift distance of protons parallel to the electric field at the shock front is considerably smaller than the local radius of curvature of the Bow Shock. The implications of the presented observations of Bow Shock crossings as to the source of the energetic proton intensity enhancements are discussed. (author)

  15. Growth Response of Aboveground and Belowground of Eustoma grandiflorum to Elevated Co2 in Hydroponic Culture

    Directory of Open Access Journals (Sweden)

    mahin nikoo

    2018-03-01

    Full Text Available Introduction: One of the climate change sign is variation in greenhouse gases in the Earth's atmosphere. Carbon dioxide is the most important greenhouse gas that is released into the atmosphere by humans. It is expected that addition of carbon dioxide could effect the energy balance and global climate. Climate change is effective on agricultural productions. It is clear that different plants have different responses to Co2 variation. These responses are consisting of yield, growth characteristic and variation in root/shoot ratio of plants. On the other hand, using growing media are expanding for plants because of their advantages such as plants nutrient control, reducing the incidence of diseases and pests and increasing the quantity and quality rather than soil cultivation. Properties of various materials as substrates influence directly or indirectly on plant growth and crop production., Hydroponic method can be considered as one of the important methods to optimize water use in agriculture, especially in many countries are located in arid and semi-arid regions that have water crisis. Lisianthus is one of the most beautiful flowers with folded petals in white, blue and purple. I-ts scientific name is Eustoma grandiflorum from the family of Gentianaceae and native to North America. It has variety of annual, biennial or short-lived perennial. The aim of this study was to explore the effect of Co2 enrichment on growth response of aboveground and belowground of Eustoma grandiflorum under increasing of Co2 greenhouse gases in hydroponic culture. Materials and Methods: The experiment was done as a split-plot based on completely randomized experimental design with three replications at greenhouse of Ferdowsi University of Mashhad. The treatments were consists of three concentrations of carbon dioxide (380 as controls, 750 and 1050 ppm as main plots and two cultivars Yodel white and GCREC-blue as subplots. Some characteristic such as plant height

  16. Similar below-ground carbon cycling dynamics but contrasting modes of nitrogen cycling between arbuscular mycorrhizal and ectomycorrhizal forests.

    Science.gov (United States)

    Lin, Guigang; McCormack, M Luke; Ma, Chengen; Guo, Dali

    2017-02-01

    Compared with ectomycorrhizal (ECM) forests, arbuscular mycorrhizal (AM) forests are hypothesized to have higher carbon (C) cycling rates and a more open nitrogen (N) cycle. To test this hypothesis, we synthesized 645 observations, including 22 variables related to below-ground C and N dynamics from 100 sites, where AM and ECM forests co-occurred at the same site. Leaf litter quality was lower in ECM than in AM trees, leading to greater forest floor C stocks in ECM forests. By contrast, AM forests had significantly higher mineral soil C concentrations, and this result was strongly mediated by plant traits and climate. No significant differences were found between AM and ECM forests in C fluxes and labile C concentrations. Furthermore, inorganic N concentrations, net N mineralization and nitrification rates were all higher in AM than in ECM forests, indicating 'mineral' N economy in AM but 'organic' N economy in ECM trees. AM and ECM forests show systematic differences in mineral vs organic N cycling, and thus mycorrhizal type may be useful in predicting how different tree species respond to multiple environmental change factors. By contrast, mycorrhizal type alone cannot reliably predict below-ground C dynamics without considering plant traits and climate. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  17. Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge

    International Nuclear Information System (INIS)

    Jones, M.L.M.; Hodges, G.; Mills, G.

    2010-01-01

    Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha -1 yr -1 . Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen x ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. - Nitrogen alters threshold of ozone-induced senescence, but not below-ground resource allocation.

  18. Belowground neighbor perception in Arabidopsis thaliana studied by transcriptome analysis: roots of Hieracium pilosella cause biotic stress

    Directory of Open Access Journals (Sweden)

    Christoph eSchmid

    2013-08-01

    Full Text Available Root-root interactions are much more sophisticated than previously thought, yet the mechanisms of belowground neighbor perception remain largely obscure. Genome-wide transcriptome analyses allow detailed insight into plant reactions to environmental cues.A root interaction trial was set up to explore both morphological and whole genome transcriptional responses in roots of Arabidopsis thaliana in the presence or absence of an inferior competitor, Hieracium pilosella.Neighbor perception was indicated by Arabidopsis roots predominantly growing away from the neighbor (segregation, while solitary plants placed more roots towards the middle of the pot. Total biomass remained unaffected. Database comparisons in transcriptome analysis revealed considerable similarity between Arabidopsis root reactions to neighbors and reactions to pathogens. Detailed analyses of the functional category ‘biotic stress’ using MapMan tools found the sub-category ‘pathogenesis-related proteins’ highly significantly induced. A comparison to a study on intraspecific competition brought forward a core of genes consistently involved in reactions to neighbor roots.We conclude that beyond resource depletion roots perceive neighboring roots or their associated microorganisms by a relatively uniform mechanism that involves the strong induction of pathogenesis-related proteins. In an ecological context the findings reveal that belowground neighbor detection may occur independently of resource depletion, allowing for a time advantage for the root to prepare for potential interactions.

  19. Numerical scheme for optimization of xenon transient processes in a reactor. Problem on fast response without a limitation for phase variables

    International Nuclear Information System (INIS)

    Gerasimov, A.S.

    1975-01-01

    A numerical diagram is suggested of minimizing a period of xenon transient process in the reactor without any limitation of xenon-135 concentration. The problem is solved with a computer in a point model. Pontryagin's maximum principle is used so as to check optimization of the transient process

  20. A statistical rationale for establishing process quality control limits using fixed sample size, for critical current verification of SSC superconducting wire

    International Nuclear Information System (INIS)

    Pollock, D.A.; Brown, G.; Capone, D.W. II; Christopherson, D.; Seuntjens, J.M.; Woltz, J.

    1992-03-01

    The purpose of this paper is to demonstrate a statistical method for verifying superconducting wire process stability as represented by I c . The paper does not propose changing the I c testing frequency for wire during Phase 1 of the present Vendor Qualification Program. The actual statistical limits demonstrated for one supplier's data are not expected to be suitable for all suppliers. However, the method used to develop the limits and the potential for improved process through their use, may be applied equally. Implementing the demonstrated method implies that the current practice of testing all pieces of wire from each billet, for the purpose of detecting manufacturing process errors (i.e. missing a heat-treatment cycle for a part of the billet, etc.) can be replaced by other less costly process control measures. As used in this paper process control limits for critical current are quantitative indicators of the source manufacturing process uniformity. The limits serve as alarms indicating the need for manufacturing process investigation

  1. Soil respiration in Tibetan alpine grasslands: belowground biomass and soil moisture, but not soil temperature, best explain the large-scale patterns.

    Directory of Open Access Journals (Sweden)

    Yan Geng

    Full Text Available The Tibetan Plateau is an essential area to study the potential feedback effects of soils to climate change due to the rapid rise in its air temperature in the past several decades and the large amounts of soil organic carbon (SOC stocks, particularly in the permafrost. Yet it is one of the most under-investigated regions in soil respiration (Rs studies. Here, Rs rates were measured at 42 sites in alpine grasslands (including alpine steppes and meadows along a transect across the Tibetan Plateau during the peak growing season of 2006 and 2007 in order to test whether: (1 belowground biomass (BGB is most closely related to spatial variation in Rs due to high root biomass density, and (2 soil temperature significantly influences spatial pattern of Rs owing to metabolic limitation from the low temperature in cold, high-altitude ecosystems. The average daily mean Rs of the alpine grasslands at peak growing season was 3.92 µmol CO(2 m(-2 s(-1, ranging from 0.39 to 12.88 µmol CO(2 m(-2 s(-1, with average daily mean Rs of 2.01 and 5.49 µmol CO(2 m(-2 s(-1 for steppes and meadows, respectively. By regression tree analysis, BGB, aboveground biomass (AGB, SOC, soil moisture (SM, and vegetation type were selected out of 15 variables examined, as the factors influencing large-scale variation in Rs. With a structural equation modelling approach, we found only BGB and SM had direct effects on Rs, while other factors indirectly affecting Rs through BGB or SM. Most (80% of the variation in Rs could be attributed to the difference in BGB among sites. BGB and SM together accounted for the majority (82% of spatial patterns of Rs. Our results only support the first hypothesis, suggesting that models incorporating BGB and SM can improve Rs estimation at regional scale.

  2. Aboveground and belowground legacies of native Sami land use on boreal forest in northern Sweden 100 years after abandonment.

    Science.gov (United States)

    Freschet, Grégoire T; Ostlund, Lars; Kichenin, Emilie; Wardle, David A

    2014-04-01

    Human activities that involve land-use change often cause major transformations to community and ecosystem properties both aboveground and belowground, and when land use is abandoned, these modifications can persist for extended periods. However, the mechanisms responsible for rapid recovery vs. long-term maintenance of ecosystem changes following abandonment remain poorly understood. Here, we examined the long-term ecological effects of two remote former settlements, regularly visited for -300 years by reindeer-herding Sami and abandoned -100 years ago, within an old-growth boreal forest that is considered one of the most pristine regions in northern Scandinavia. These human legacies were assessed through measurements of abiotic and biotic soil properties and vegetation characteristics at the settlement sites and at varying distances from them. Low-intensity land use by Sami is characterized by the transfer of organic matter towards the settlements by humans and reindeer herds, compaction of soil through trampling, disappearance of understory vegetation, and selective cutting of pine trees for fuel and construction. As a consequence, we found a shift towards early successional plant species and a threefold increase in soil microbial activity and nutrient availability close to the settlements relative to away from them. These changes in soil fertility and vegetation contributed to 83% greater total vegetation productivity, 35% greater plant biomass, and 23% and 16% greater concentrations of foliar N and P nearer the settlements, leading to a greater quantity and quality of litter inputs. Because decomposer activity was also 40% greater towards the settlements, soil organic matter cycling and nutrient availability were further increased, leading to likely positive feedbacks between the aboveground and belowground components resulting from historic land use. Although not all of the activities typical of Sami have left visible residual traces on the ecosystem after

  3. Luxury consumption of soil nutrients: a possible competitive strategy in above-ground and below-ground biomass allocation and root morphology for slow-growing arctic vegetation?

    NARCIS (Netherlands)

    Wijk, van M.T.; Williams, M.; Gough, L.; Hobbie, S.E.; Shaver, G.R.

    2003-01-01

    1 A field-experiment was used to determine how plant species might retain dominance in an arctic ecosystem receiving added nutrients. We both measured and modelled the above-ground and below-ground biomass allocation and root morphology of non-acidic tussock tundra near Toolik Lake, Alaska, after 4

  4. Application of Computer-Aided Tomography (CT) Technology to Visually Compare Belowground Components of Salt Marshes in Jamaica Bay and Long Island, New York

    Science.gov (United States)

    Using CT imaging, we found that rapidly deteriorating marshes in Jamaica Bay had significantly less belowground mass and abundance of coarse roots and rhizomes at depth (< 10 cm) compared to more stable areas in the Jamaica Bay Estuary. In addition, the rhizome diameters and pea...

  5. The relative importance of above- versus belowground competition for tree growth and survival during early succession of a tropical moist forest

    NARCIS (Netherlands)

    Breugel, van M.; Breugel, van P.; Jansen, P.A.; Martinez-Ramos, M.; Bongers, F.

    2012-01-01

    Competition between neighboring plants plays a major role in the population dynamics of tree species in the early phases of humid tropical forest succession. We evaluated the relative importance of above- versus below-ground competition during the first years of old-field succession on soil with low

  6. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites

    NARCIS (Netherlands)

    Aratchige, N.S.; Lesna, I.; Sabelis, M.W.

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract

  7. 40 CFR Appendix A to Part 419 - Processes Included in the Determination of BAT Effluent Limitations for Total Chromium...

    Science.gov (United States)

    2010-07-01

    ..., and Phenolic Compounds (4AAP) Crude Processes 1. Atmospheric Crude Distillation 2. Crude Desalting 3. Vacuum Crude Distillation Cracking and Coking Processes 4. Visbreaking 5. Thermal Cracking 6. Fluid... Oil Manufacture 23. Propane Dewaxing, Propane Deasphalting, Propane Fractioning, Propane Deresining 24...

  8. Design and performance of combined infrared canopy and belowground warming in the B4WarmED (Boreal Forest Warming at an Ecotone in Danger) experiment.

    Science.gov (United States)

    Rich, Roy L; Stefanski, Artur; Montgomery, Rebecca A; Hobbie, Sarah E; Kimball, Bruce A; Reich, Peter B

    2015-06-01

    Conducting manipulative climate change experiments in complex vegetation is challenging, given considerable temporal and spatial heterogeneity. One specific challenge involves warming of both plants and soils to depth. We describe the design and performance of an open-air warming experiment called Boreal Forest Warming at an Ecotone in Danger (B4WarmED) that addresses the potential for projected climate warming to alter tree function, species composition, and ecosystem processes at the boreal-temperate ecotone. The experiment includes two forested sites in northern Minnesota, USA, with plots in both open (recently clear-cut) and closed canopy habitats, where seedlings of 11 tree species were planted into native ground vegetation. Treatments include three target levels of plant canopy and soil warming (ambient, +1.7°C, +3.4°C). Warming was achieved by independent feedback control of voltage input to aboveground infrared heaters and belowground buried resistance heating cables in each of 72-7.0 m(2) plots. The treatments emulated patterns of observed diurnal, seasonal, and annual temperatures but with superimposed warming. For the 2009 to 2011 field seasons, we achieved temperature elevations near our targets with growing season overall mean differences (∆Tbelow ) of +1.84°C and +3.66°C at 10 cm soil depth and (∆T(above) ) of +1.82°C and +3.45°C for the plant canopies. We also achieved measured soil warming to at least 1 m depth. Aboveground treatment stability and control were better during nighttime than daytime and in closed vs. open canopy sites in part due to calmer conditions. Heating efficacy in open canopy areas was reduced with increasing canopy complexity and size. Results of this study suggest the warming approach is scalable: it should work well in small-statured vegetation such as grasslands, desert, agricultural crops, and tree saplings (<5 m tall). © 2015 John Wiley & Sons Ltd.

  9. Evaluating the effectiveness of mulch application to store carbon belowground: Short-term effects of mulch application on soluble soil and microbial C and N in agricultural soils with low and high organic matter

    Science.gov (United States)

    Chen, Janet; Heiling, Maria; Resch, Christian; Gruber, Roman; Dercon, Gerd

    2017-04-01

    Agricultural soils have the potential to contain a large pool of carbon and, depending on the farming techniques applied, can either effectively store carbon belowground, or further release carbon, in the form of CO2, into the atmosphere. Farming techniques, such as mulch application, are frequently proposed to increase carbon content belowground and improve soil quality and can be used in efforts to reduce greenhouse gas levels, such as in the "4 per 1000" Initiative. To test the effectiveness of mulch application to store carbon belowground in the short term and improve soil nutrient quality, we maintained agricultural soils with low and high organic carbon content (disturbed top soil from local Cambisols and Chernozems) in greenhouse mesocosms (70 cm deep with a radius of 25 cm) with controlled moisture for 4 years. Over the 4 years, maize and soybean were grown yearly in rotation and mulch was removed or applied to soils once plant material was harvested at 2 ton/ha dry matter. In addition, soil disturbance was kept to a minimum, with only surface disturbance of a few centimeters to keep soil free from weeds. After 4 years, we measured effects of mulch application on soluble soil and microbial carbon and nitrogen in the mesocosms and compared effects of mulch application versus no mulch on soils from 0-5 cm and 5-15 cm with low and high organic matter. We predicted that mulch would increase soil carbon and nitrogen content and mulch application would have a greater effect on soils with low organic matter than soils with high organic matter. In soils with low organic carbon content and larger predicted potential to increase soil carbon, mulch application did not increase soluble soil or microbial carbon or nitrogen compared to the treatments without mulch application. However, mulch application significantly increased the δ13C of both microbial and soluble soil carbon in these soils by 1 ‰ each, indicating a shift in belowground processes, such as increased

  10. Anaerobic digestion of animal by-products and slaughterhouse waste: main process limitations and microbial community interactions

    OpenAIRE

    Palatsi Civit, Jordi; Viñas, Marc; Guivernau, Miriam; Fernández García, Belén; Flotats Ripoll, Xavier

    2011-01-01

    Fresh pig/cattle slaughterhouse waste mixtures, with different lipid-protein ratios, were characterized and their anaerobic biodegradability assessed in batch tests. The resultant methane potentials were high (270–300 LCH4 kg 1 COD) making them interesting substrates for the anaerobic digestion process. However, when increasing substrate concentrations in consecutive batch tests, up to 15 gCOD kg 1, a clear inhibitory process was monitored. Despite the reported severe inhibition, related to l...

  11. Building sustainable communities using sense of place indicators in three Hudson River Valley, NY, tourism destinations: An application of the limits of acceptable change process

    Science.gov (United States)

    Laura E. Sullivan; Rudy M. Schuster; Diane M. Kuehn; Cheryl S. Doble; Duarte. Morais

    2010-01-01

    This study explores whether measures of residents' sense of place can act as indicators in the Limits of Acceptable Change (LAC) process to facilitate tourism planning and management. Data on community attributes valued by residents and the associated values and meanings were collected through focus groups with 27 residents in three Hudson River Valley, New York,...

  12. The Effect of Thermo-mechanical Processing on the Ballistic Limit Velocity of Extra Low Interstitial Titanium Alloy Ti-6AL- 4V

    National Research Council Canada - National Science Library

    Burkins, Matthew

    2000-01-01

    .... Department of Energy's Albany Research Center (ARC) performed a joint research program to evaluate the effect of thermo-mechanical processing on the ballistic limit velocity for an extra-low interstitial grade of the titanium alloy Ti-6Al-4V...

  13. Mesophilic co-digestion of dairy manure and lipid rich solid slaughterhouse wastes: process efficiency, limitations and floating granules formation.

    Science.gov (United States)

    Pitk, Peep; Palatsi, Jordi; Kaparaju, Prasad; Fernández, Belén; Vilu, Raivo

    2014-08-01

    Lipid and protein rich solid slaughterhouse wastes are attractive co-substrates to increase volumetric biogas production in co-digestion with dairy manure. Addition of decanter sludge (DS), containing 42.2% of lipids and 35.8% of proteins (total solids basis), up to 5% of feed mixture resulted in a stable process without any indication of long chain fatty acids (LCFA) or free ammonia (NH3) inhibition and in 3.5-fold increase of volumetric biogas production. Contrary, only lipids addition as technical fat (TF) at over 2% of feed mixture resulted in formation of floating granules (FG) and process efficiency decrease. Formed FG had low biodegradability and its organic part was composed of lipids and calcium salts of LCFAs. Anaerobic digestion process intentionally directed to FG formation, could be a viable option for mitigation and control of lipids overload and derived LCFA inhibition. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Materials processing strategies for colloidal quantum dot solar cells: advances, present-day limitations, and pathways to improvement

    KAUST Repository

    Carey, Graham H.

    2013-05-13

    Colloidal quantum dot photovoltaic devices have improved from initial, sub-1% solar power conversion efficiency to current record performance of over 7%. Rapid advances in materials processing and device physics have driven this impressive performance progress. The highest-efficiency approaches rely on a fabrication process that starts with nanocrystals in solution, initially capped with long organic molecules. This solution is deposited and the resultant film is treated using a solution containing a second, shorter capping ligand, leading to a cross-linked, non-redispersible, and dense layer. This procedure is repeated, leading to the widely employed layer-by-layer solid-state ligand exchange. We will review the properties and features of this process, and will also discuss innovative pathways to creating even higher-performing films and photovoltaic devices.

  15. Materials processing strategies for colloidal quantum dot solar cells: advances, present-day limitations, and pathways to improvement

    KAUST Repository

    Carey, Graham H.; Chou, Kang Wei; Yan, Buyi; Kirmani, Ahmad R.; Amassian, Aram; Sargent, Edward H.

    2013-01-01

    Colloidal quantum dot photovoltaic devices have improved from initial, sub-1% solar power conversion efficiency to current record performance of over 7%. Rapid advances in materials processing and device physics have driven this impressive performance progress. The highest-efficiency approaches rely on a fabrication process that starts with nanocrystals in solution, initially capped with long organic molecules. This solution is deposited and the resultant film is treated using a solution containing a second, shorter capping ligand, leading to a cross-linked, non-redispersible, and dense layer. This procedure is repeated, leading to the widely employed layer-by-layer solid-state ligand exchange. We will review the properties and features of this process, and will also discuss innovative pathways to creating even higher-performing films and photovoltaic devices.

  16. Strengths and Limitations of the Education, Health and Care Plan Process from a Range of Professional and Family Perspectives

    Science.gov (United States)

    Sales, Niaomi; Vincent, Kerry

    2018-01-01

    The introduction of a new Special Educational Needs and Disability (SEND) Code of Practice in 2015 marked one of the most significant reforms to the SEND statutory assessment process in England since its introduction over 30 years ago. This article presents the findings of a small-scale study that aimed to identify the extent to which the reforms…

  17. Storage of intact heads prior to processing limits the shelf-life of fresh-cut Lactuca sativa L.

    NARCIS (Netherlands)

    Witkowska, I.M.; Woltering, E.J.

    2014-01-01

    Harvested lettuce heads are usually transported and stored for some period of time under a variety of conditions prior to processing. During storage, especially under suboptimal conditions, nutritional composition of the harvested produce continues to change. The possible impact of prior storage of

  18. Limitations of the removal of cyanide from coking wastewater by ozonation and by the hydrogen peroxide-ozone process.

    Science.gov (United States)

    Pueyo, N; Miguel, N; Ovelleiro, J L; Ormad, M P

    The purpose of this study is to compare the efficiency of ozonation and the hydrogen peroxide-ozone process for the removal of cyanide from coking wastewater. The most efficient oxidation process is combined with coagulation-flocculation-decantation and lime-soda ash softening pretreatments. The oxidation in aqueous solution and industrial wastewater (at pH 9.5-12.3) by O3 was carried out using a range of concentration of consumed O3 from 10 to 290 mg/L. A molar ratio of H2O2/O3 from 0.1 to 5.2 with different concentrations of O3 constants was used for the H2O2-O3 process. The maximum cyanide removal obtained in coking wastewater was 90% using a mass ratio of O3/CN(-) of 9.5. Using lower concentrations of O3, cyanide is not removed and can even be generated due to the presence of other cyanide precursor organic micropollutants in the industrial matrix. The concentration of O3 is reduced to half for the same cyanide removal efficiency if the pretreatments are applied to reduce the carbonate and bicarbonate ions. The cyanide removal efficiency in coking wastewater is not improved if the O3 is combined with the H2O2. However, the preliminary cyanide removal treatment in aqueous solution showed an increase in the cyanide removal efficiency for the H2O2-O3 process.

  19. [Logic model of the Franche-Comté Regional Health Project: advantages and limitations for the evaluation process].

    Science.gov (United States)

    Michaud, Claude; Sannino, Nadine; Duboudin, Cédric; Baudier, François; Guillin, Caroline; Billondeau, Christine; Mansion, Sylvie

    2014-01-01

    The French "Hospitals, patients, health and territories" law of July 2009 created the Regional Health Project (PRS) to support regional health policy, and requires evaluation of these projects. The construction of these projects, which includes prevention planning, care planning, and medical and social welfare planning, presents an unprecedented complexity in France, where evaluation programmes are still in their infancy. To support future evaluations, the Franche-Comté Regional Health Agency (ARS FC), assisted by the expertise of EFECT Consultants, decided to reconstruct the PRS logic model. This article analyzes the advantages and limitations of this approach. The resulting logic model allows visualization of the strategy adopted to achieve the Franche-Comté PRS ambitions and expected results. The model highlights four main aspects of structural change to the health system, often poorly visible in PRS presentation documents. This model also establishes links with the usual public policy evaluation issues and facilitates their prioritization. This approach also provides a better understanding of the importance of analysis of the programme construction in order to be effective rather than direct analysis of the effects, which constitutes the natural tendency of current practice. The main controversial limit concerns the retrospective design of the PRS framework, both in terms of the reliability of interpretation and adoption by actors not directly involved in this initiative.

  20. Harmonisation of licensing processes for decommissioning. Options and limitations; Genehmigungsverfahren fuer die Stilllegung der deutschen Kernkraftwerke. Konvoi oder Kakophonie?

    Energy Technology Data Exchange (ETDEWEB)

    Raetzke, Christian

    2016-03-15

    The shutdown of eight reactors in Germany in the wake of Fukushima 2011 and the scheduled phase-out of the remaining units in several steps ending 2022 has obviously triggered a wave of applications for decommissioning and dismantling licences. It would seem natural to strive for a harmonised handling of these processes, analogous to the 'convoi' concept which was successfully employed for licensing and construction of the three most recent German NPPs in the 1980s. However, a comparative analysis shows that the motivation of all players is much different from that of earlier times and that harmonisation of licensing processes for dismantling is not as crucial for operators, authorities and technical support organisations as it was for construction.

  1. Limited evidence of individual differences in holistic processing in different versions of the part-whole paradigm.

    Science.gov (United States)

    Sunday, Mackenzie A; Richler, Jennifer J; Gauthier, Isabel

    2017-07-01

    The part-whole paradigm was one of the first measures of holistic processing and it has been used to address several topics in face recognition, including its development, other-race effects, and more recently, whether holistic processing is correlated with face recognition ability. However the task was not designed to measure individual differences and it has produced measurements with low reliability. We created a new holistic processing test designed to measure individual differences based on the part-whole paradigm, the Vanderbilt Part Whole Test (VPWT). Measurements in the part and whole conditions were reliable, but, surprisingly, there was no evidence for reliable individual differences in the part-whole index (how well a person can take advantage of a face part presented within a whole face context compared to the part presented without a whole face) because part and whole conditions were strongly correlated. The same result was obtained in a version of the original part-whole task that was modified to increase its reliability. Controlling for object recognition ability, we found that variance in the whole condition does not predict any additional variance in face recognition over what is already predicted by performance in the part condition.

  2. The pre-rRNA processing factor DEF is rate limiting for the pathogenesis of MYCN-driven neuroblastoma.

    Science.gov (United States)

    Tao, T; Sondalle, S B; Shi, H; Zhu, S; Perez-Atayde, A R; Peng, J; Baserga, S J; Look, A T

    2017-07-06

    The nucleolar factor, digestive organ expansion factor (DEF), has a key role in ribosome biogenesis, functioning in pre-ribosomal RNA (pre-rRNA) processing as a component of the small ribosomal subunit (SSU) processome. Here we show that the peripheral sympathetic nervous system (PSNS) is very underdeveloped in def-deficient zebrafish, and that def haploinsufficiency significantly decreases disease penetrance and tumor growth rate in a MYCN-driven transgenic zebrafish model of neuroblastoma that arises in the PSNS. Consistent with these findings, DEF is highly expressed in human neuroblastoma, and its depletion in human neuroblastoma cell lines induces apoptosis. Interestingly, overexpression of MYCN in zebrafish and in human neuroblastoma cells results in the appearance of intermediate pre-rRNAs species that reflect the processing of pre-rRNAs through Pathway 2, a pathway that processes pre-rRNAs in a different temporal order than the more often used Pathway 1. Our results indicate that DEF and possibly other components of the SSU processome provide a novel site of vulnerability in neuroblastoma cells that could be exploited for targeted therapy.

  3. The sky is the limit? 20 years of small-format aerial photography taken from UAS for monitoring geomorphological processes

    Science.gov (United States)

    Marzolff, Irene

    2014-05-01

    One hundred years after the first publication on aerial photography taken from unmanned aerial platforms (Arthur Batut 1890), small-format aerial photography (SFAP) became a distinct niche within remote sensing during the 1990s. Geographers, plant biologists, archaeologists and other researchers with geospatial interests re-discovered the usefulness of unmanned platforms for taking high-resolution, low-altitude photographs that could then be digitized and analysed with geographical information systems, (softcopy) photogrammetry and image processing techniques originally developed for digital satellite imagery. Even before the ubiquity of digital consumer-grade cameras and 3D analysis software accessible to the photogrammetric layperson, do-it-yourself remote sensing using kites, blimps, drones and micro air vehicles literally enabled the questing researcher to get their own pictures of the world. As a flexible, cost-effective method, SFAP offered images with high spatial and temporal resolutions that could be ideally adapted to the scales of landscapes, forms and distribution patterns to be monitored. During the last five years, this development has been significantly accelerated by the rapid technological advancements of GPS navigation, autopiloting and revolutionary softcopy-photogrammetry techniques. State-of-the-art unmanned aerial systems (UAS) now allow automatic flight planning, autopilot-controlled aerial surveys, ground control-free direct georeferencing and DEM plus orthophoto generation with centimeter accuracy, all within the space of one day. The ease of use of current UAS and processing software for the generation of high-resolution topographic datasets and spectacular visualizations is tempting and has spurred the number of publications on these issues - but which advancements in our knowledge and understanding of geomorphological processes have we seen and can we expect in the future? This presentation traces the development of the last two decades

  4. Involving private persons and corporations in the planning process according to paragraph 9b German nuclear law - practicability and limits

    International Nuclear Information System (INIS)

    Altmann, J.; Roesel, H.

    1978-01-01

    The 4th Amendment to the German Nuclear Law has procured the legal base for the disposal of radioactive waste in the German Federal Republic. The Nuclear Law states that the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig is responsible for the disposal of radioactive waste. The PTB can be assisted in its responsibilities by persons and institutions of private character. Involving private persons and corporations in the licensing process figures a legal problem, and there has been a seminar in the PTB discussing such problems. The present contribution gives a brief summary of the opinions stated by the various legal experts taking part in this seminar. (orig./HP) [de

  5. An Alternative Approach to Overcome the Limitation of HRUs in Analyzing Hydrological Processes Based on Land Use/Cover Change

    Directory of Open Access Journals (Sweden)

    Fanhao Meng

    2018-04-01

    Full Text Available Since the concept of hydrological response units (HRUs is used widely in hydrological modeling, the land use change scenarios analysis based on HRU may have direct influence on hydrological processes due to its simplified flow routing and HRU spatial distribution. This paper intends to overcome this issue based on a new analysis approach to explain what impacts for the impact of land use/cover change on hydrological processes (LUCCIHP, and compare whether differences exist between the conventional approach and the improved approach. Therefore, we proposed a sub-basin segmentation approach to obtain more reasonable impact assessment of LUCC scenario by re-discretizing the HRUs and prolonging the flow path in which the LUCC occurs. As a scenario study, the SWAT model is used in the Aksu River Basin, China, to simulate the response of hydrological processes to LUCC over ten years. Moreover, the impacts of LUCC on hydrological processes before and after model modification are compared and analyzed at three levels (catchment scale, sub-basin scale and HRU scale. Comparative analysis of Nash–Sutcliffe coefficient (NSE, RSR and Pbias, model simulations before and after model improvement shows that NSE increased by up to 2%, RSR decreased from 0.73 to 0.72, and Pbias decreased from 0.13 to 0.05. The major LUCCs affecting hydrological elements in this basin are related to the degradation of grassland and snow/ice and expansion of farmland and bare land. Model simulations before and after model improvement show that the average variation of flow components in typical sub-basins (surface runoff, lateral flow and groundwater flow are changed by +11.09%, −4.51%, and −6.58%, and +10.53%, −1.55%, and −8.98% from the base period model scenario, respectively. Moreover, the spatial response of surface runoff at the HRU level reveals clear spatial differences between before and after model improvement. This alternative approach illustrates the potential

  6. An Investigation into the Effects of Process Conditions on the Tribological Performance of Pack Carburized Titanium with Limited Oxygen Diffusion

    Science.gov (United States)

    Bailey, R.; Sun, Y.

    2018-04-01

    In the present study, a new pack carburization technique for titanium has been investigated. The aim of this treatment is to produce a titanium carbide/oxycarbide layer atop of an extended oxygen diffusion zone [α-Ti(O)]. The effects of treatment temperature and pack composition have been investigated in order to determine the optimal conditions required to grant the best tribological response. The resulting structural features were investigated with particular interest in the carbon and oxygen concentrations across the samples cross section. The optimization showed that a temperature of 925 °C with a pack composition of 1 part carbon to 1 part energizer produced surface capable of withstanding a contact pressure of ≈ 1.5 GPa for 1 h. The process resulted in TiC surface structure which offers enhanced hardness (2100 HV) and generates a low friction coefficient (μ ≈ 0.2) when in dry sliding contact with an alumina (Al2O3) ball. The process also produced an extended oxygen diffusion zone that helps to improve the load bearing capacity of the substrate.

  7. Protective effect of milk constituents and sublethal injuries limiting process effectiveness during PEF inactivation of Lb. rhamnosus.

    Science.gov (United States)

    Jaeger, H; Schulz, A; Karapetkov, N; Knorr, D

    2009-08-31

    The inactivation of Lb. rhamnosus by pulsed electric field treatment (PEF) was studied in different fractions of raw milk and Ringer solution in order to evaluate the protective effect of nutrient rich media in comparison to aqueous buffer solutions. Apart from monitoring of culturability, analysis of the physiological fitness of Lb. rhamnosus was conducted aiming to identify sublethally damaged cells. Therefore, flow cytometry and a selective medium plating technique were used and compared to each other. The goal of the study was to apply three different parameters describing the physiological fitness of the model organism Lb. rhamnosus after PEF treatment such as culturability, membrane permeability and metabolic activity depending on treatment media and parameters. A concentration dependent protective effect of the milk protein fraction could be shown and allocated to micellar casein as the major milk protein. Increasing the concentration of whey proteins up to 2% showed a similar impact on limiting the PEF inactivation of Lb. rhamnosus. The evaluation of physiological fitness of cells was based on a determination of structural and functional characteristics by rapid cellular staining using carboxyfluorescein diacetate and propidium iodide. This approach showed good accordance to the conventional selective medium plating technique for the enumeration of sublethally-injured bacteria but flow cytometry provided additional information for the characterisation of this fraction. The extent of occurrence of dead, sublethal and vital fractions of cells was found dependent on the PEF treatment parameters such as electrical field strength and energy input as well as the different milk fractions used as treatment media.

  8. Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock: FY17 Progress. Predecisional Draft

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Liange; Rutqvist, Jonny; Xu, Hao; Kim, Kunwhi; Voltolini, Marco; Cao, Xiaoyuan

    2017-07-03

    The focus of research within the Spent Fuel and Waste Science and Technology (SFWST) (formerly called Used Fuel Disposal) Campaign is on repository-induced interactions that may affect the key safety characteristics of EBS bentonite and an argillaceous rock. These include thermal-hydrologicalmechanical- chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer materials and petrophysical characteristics, particularly the impacts of temperature rise caused by waste heat. This report documents the following research activities. Section 2 presents THM model developments and validation, including modeling of underground heater experiments at Mont Terri and Bure underground research laboratories (URLs). The heater experiments modeled are the Mont Terri FE (Full-scale Emplacement) Experiment, conducted as part of the Mont Terri Project, and the TED in heater test conducted in Callovo-Oxfordian claystone (COx) at the Meuse/Haute-Marne (MHM) underground research laboratory in France. The modeling of the TED heater test is one of the Tasks of the DEvelopment of COupled Models and their VAlidation against EXperiments (DECOVALEX)-2019 project. Section 3 presents the development and application of thermal-hydrological-mechanical-chemical (THMC) modeling to evaluate EBS bentonite and argillite rock responses under different temperatures (100 °C and 200 °C). Model results are presented to help to understand the impact of high temperatures on the properties and behavior of bentonite and argillite rock. Eventually the process model will support a robust GDSA model for repository performance assessments. Section 4 presents coupled THMC modeling for an in situ test conducted at Grimsel underground laboratory in Switzerland in the Full

  9. Why do NRM regional planning processes and tools have limited effect? Presenting the perspective of the end user

    Directory of Open Access Journals (Sweden)

    Dana Reiter

    2017-01-01

    Full Text Available Natural resource managers are required to prepare a plan for managing the natural resources in their regions. Environmental decision support systems (EDSS have been developed to assist managers and stakeholders make decisions about complex natural resource problems. Research has shown that these EDSS are valuable and used internationally. However, sustainability science literature reports that too often these natural resource management (NRM plans are not consulted upon completion, and the EDSS are no longer used. To gain insight into why the EDSS are no longer used after the research and development phase of the NRM planning project, we have asked the stakeholders, as end users of the EDSS tool themselves, to share their perceptions of, and experience with development of the tool and then, the tool itself. This paper reports on the perspectives of the end users of an EDSS used in a South Australian NRM planning project from 2011 to 2013. The findings were mixed in that they show that the majority (90% of respondents felt the EDSS had overall value, yet it was virtually abandoned after the completion of the planning project. Further, just over half of respondents reported that they thought that the EDSS should have been used on a regular basis after the pilot project ended. We conclude that genuine capacity development, aided by the EDSS, took place during the project. However, the lack of use of the EDSS after the pilot project finished was the result of failures both with researcher follow up and especially with the lack of commitment from government agencies who support and influence the array of end users. Unless agencies commit to the changed practices identified by end users that would support ongoing use of EDSS it is inevitable that the legacy value of EDSS development will remain limited.

  10. Allometry and partitioning of above- and below-ground biomass in farmed eucalyptus species dominant in Western Kenyan agricultural landscapes

    International Nuclear Information System (INIS)

    Kuyah, Shem; Dietz, Johannes; Muthuri, Catherine; Noordwijk, Meine van; Neufeldt, Henry

    2013-01-01

    Farmers in developing countries are one of the world's largest and most efficient producers of sequestered carbon. However, measuring, monitoring and verifying how much carbon trees in smallholder farms are removing from the atmosphere has remained a great challenge in developing nations. Devising a reliable way for measuring carbon associated with trees in agricultural landscapes is essential for helping smallholder farmers benefit from emerging carbon markets. This study aimed to develop biomass equations specific to dominant eucalyptus species found in agricultural landscapes in Western Kenya. Allometric relationships were developed by regressing diameter at breast height (DBH) alone or DBH in combination with height, wood density or crown area against the biomass of 48 trees destructively sampled from a 100 km 2 site. DBH alone was a significant predictor variable and estimated aboveground biomass (AGB) with over 95% accuracy. The stems, branches and leaves formed up to 74, 22 and 4% of AGB, respectively, while belowground biomass (BGB) of the harvested trees accounted for 21% of the total tree biomass, yielding an overall root-to-shoot ratio (RS) of 0.27, which varied across tree size. Total tree biomass held in live Eucalyptus trees was estimated to be 24.4 ± 0.01 Mg ha −1 , equivalent to 11.7 ± 0.01 Mg of carbon per hectare. The equations presented provide useful tools for estimating tree carbon stocks of Eucalyptus in agricultural landscapes for bio-energy and carbon accounting. These equations can be applied to Eucalyptus in most agricultural systems with similar agro-ecological settings where tree growth parameters would fall within ranges comparable to the sampled population. -- Highlights: ► Equation with DBH alone estimated aboveground biomass with about 95% accuracy. ► Local generic equations overestimated above- and below-ground biomass by 10 and 48%. ► Height, wood density and crown area data did not improve model accuracy. ► Stems

  11. Below-ground biomass production and allometric relationships of eucalyptus coppice plantation in the central highlands of Madagascar

    International Nuclear Information System (INIS)

    Razakamanarivo, Ramarson H.; Razakavololona, Ando; Razafindrakoto, Marie-Antoinette; Vieilledent, Ghislain; Albrecht, Alain

    2012-01-01

    Short rotations of Eucalyptus plantations under coppice regime are extensively managed for wood production in Madagascar. Nevertheless, little is known about their biomass production and partitioning and their potential in terms of carbon sequestration. If above-ground biomass (AGB) can be estimated based on established allometric relations, below-ground (BGB) estimates are much less common. The aim of this work was to develop allometric equations to estimate biomass of these plantations, mainly for the root components. Data from 9 Eucalyptus robusta stands (47–87 years of plantation age, 3–5 years of coppice-shoot age) were collected and analyzed. Biomass of 3 sampled trees per stand was determined destructively. Dry weight of AGB components (leaves, branches and stems) were estimated as a function of basal area of all shoots per stump and dry weight for BGB components (mainly stump, coarse root (CR) and medium root (MR)) were estimated as a function of stump circumference. Biomass was then computed using allometric equations from stand inventory data. Stand biomass ranged from 102 to 130 Mg ha −1 with more than 77% contained in the BGB components. The highest dry weight was allocated in the stump and in the CR (51% and 42% respectively) for BGB parts and in the stem (69%) for AGB part. Allometric relationships developed herein could be applied to other Eucalyptus plantations which present similar stand density and growing conditions; anyhow, more is needed to be investigated in understanding biomass production and partitioning over time for this kind of forest ecosystem. -- Highlights: ► We studied the potential of old eucalyptus coppices in Madagascar to mitigate global warming. ► Biomass measurement, mainly for below-ground BGB (stump, coarse-medium-and fine roots) was provided. ► BGB allometry relationships for short rotation forestry under coppice were established. ► BGB were found to be important with their 102-130MgC ha -1 (<77% of the C in

  12. Land-use type and intensity differentially filter traits in above- and below-ground arthropod communities.

    Science.gov (United States)

    Birkhofer, Klaus; Gossner, Martin M; Diekötter, Tim; Drees, Claudia; Ferlian, Olga; Maraun, Mark; Scheu, Stefan; Weisser, Wolfgang W; Wolters, Volkmar; Wurst, Susanne; Zaitsev, Andrey S; Smith, Henrik G

    2017-05-01

    Along with the global decline of species richness goes a loss of ecological traits. Associated biotic homogenization of animal communities and narrowing of trait diversity threaten ecosystem functioning and human well-being. High management intensity is regarded as an important ecological filter, eliminating species that lack suitable adaptations. Below-ground arthropods are assumed to be less sensitive to such effects than above-ground arthropods. Here, we compared the impact of management intensity between (grassland vs. forest) and within land-use types (local management intensity) on the trait diversity and composition in below- and above-ground arthropod communities. We used data on 722 arthropod species living above-ground (Auchenorrhyncha and Heteroptera), primarily in soil (Chilopoda and Oribatida) or at the interface (Araneae and Carabidae). Our results show that trait diversity of arthropod communities is not primarily reduced by intense local land use, but is rather affected by differences between land-use types. Communities of Auchenorrhyncha and Chilopoda had significantly lower trait diversity in grassland habitats as compared to forests. Carabidae showed the opposite pattern with higher trait diversity in grasslands. Grasslands had a lower proportion of large Auchenorrhyncha and Carabidae individuals, whereas Chilopoda and Heteroptera individuals were larger in grasslands. Body size decreased with land-use intensity across taxa, but only in grasslands. The proportion of individuals with low mobility declined with land-use intensity in Araneae and Auchenorrhyncha, but increased in Chilopoda and grassland Heteroptera. The proportion of carnivorous individuals increased with land-use intensity in Heteroptera in forests and in Oribatida and Carabidae in grasslands. Our results suggest that gradients in management intensity across land-use types will not generally reduce trait diversity in multiple taxa, but will exert strong trait filtering within

  13. Successful Aging in the Context of the Disablement Process: Working and Volunteering as Moderators on the Association Between Chronic Conditions and Subsequent Functional Limitations.

    Science.gov (United States)

    Kail, Ben Lennox; Carr, Dawn C

    2017-03-01

    This study evaluated the successful aging model by assessing the impact of two forms of productive engagement-working and volunteering-as potential interventions in the process of disablement. The Health and Retirement Study was used to (a) estimate two-stage selection equations of (i) currently working part time and full time and (ii) currently volunteering less than 100 hours and volunteering 100 hours or more per year (net of chronic health problems) and (b) assess whether, net of selection, working, and volunteering moderate the association between chronic conditions and subsequent functional limitations. Chronic conditions were associated with elevated levels of subsequent functional limitations, whereas both working and volunteering were associated with lower levels of subsequent functional limitations. Moreover, workers and volunteers of less than 100 hours per year experienced a reduction in the association of chronic conditions on subsequent functional limitations. This research highlights the role of productive engagement as a key element in successful aging. Not only do work and volunteering have direct associations with health outcomes themselves, but they also act as potential interventions in the process of disablement by attenuating the way in which chronic conditions are translated into subsequent functional limitations. This suggests that (a) future research should apply successful aging models to health processes as well as health outcomes and (b) policy makers should support social institutions that foster late-life productive engagement. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Process limitations of a whole-cell P450 catalyzed reaction using a CYP153A-CPR fusion construct expressed in Escherichia coli

    DEFF Research Database (Denmark)

    Lundemo, M. T.; Notonier, S.; Striedner, G.

    2016-01-01

    fatty acids at the terminal position. ω-Hydroxylated fatty acids can be used in the field of high-end polymers and in the cosmetic and fragrance industry. Here, we have identified the limitations for implementation of a whole-cell P450-catalyzed reaction by characterizing the chosen biocatalyst as well......Cytochrome P450s are interesting biocatalysts due to their ability to hydroxylate non-activated hydrocarbons in a selective manner. However, to date only a few P450-catalyzed processes have been implemented in industry due to the difficulty of developing economically feasible processes...

  15. Availability and temporal heterogeneity of water supply affect the vertical distribution and mortality of a belowground herbivore and consequently plant growth.

    Science.gov (United States)

    Tsunoda, Tomonori; Kachi, Naoki; Suzuki, Jun-Ichirou

    2014-01-01

    We examined how the volume and temporal heterogeneity of water supply changed the vertical distribution and mortality of a belowground herbivore, and consequently affected plant biomass. Plantago lanceolata (Plantaginaceae) seedlings were grown at one per pot under different combinations of water volume (large or small volume) and heterogeneity (homogeneous water conditions, watered every day; heterogeneous conditions, watered every 4 days) in the presence or absence of a larva of the belowground herbivorous insect, Anomala cuprea (Coleoptera: Scarabaeidae). The larva was confined in different vertical distributions to top feeding zone (top treatment), middle feeding zone (middle treatment), or bottom feeding zone (bottom treatment); alternatively no larva was introduced (control treatment) or larval movement was not confined (free treatment). Three-way interaction between water volume, heterogeneity, and the herbivore significantly affected plant biomass. With a large water volume, plant biomass was lower in free treatment than in control treatment regardless of heterogeneity. Plant biomass in free treatment was as low as in top treatment. With a small water volume and in free treatment, plant biomass was low (similar to that under top treatment) under homogeneous water conditions but high under heterogeneous ones (similar to that under middle or bottom treatment). Therefore, there was little effect of belowground herbivory on plant growth under heterogeneous water conditions. In other watering regimes, herbivores would be distributed in the shallow soil and reduced root biomass. Herbivore mortality was high with homogeneous application of a large volume or heterogeneous application of a small water volume. Under the large water volume, plant biomass was high in pots in which the herbivore had died. Thus, the combinations of water volume and heterogeneity affected plant growth via the change of a belowground herbivore.

  16. Epiphyte-cover on seagrass (Zostera marina L. leaves impedes plant performance and radial O2 loss from the below-ground tissue

    Directory of Open Access Journals (Sweden)

    Kasper Elgetti Brodersen

    2015-08-01

    Full Text Available The O2 budget of seagrasses is a complex interaction between several sources and sinks, which is strongly regulated by light availability and mass transfer over the diffusive boundary layer (DBL surrounding the plant. Epiphyte growth on leaves may thus strongly affect the O2 availability of the seagrass plant and its capability to aerate its rhizosphere as a defence against plant toxins.We used electrochemical and fiber-optic microsensors to quantify the O2 flux, DBL and light microclimate around leaves with and without filamentous algal epiphytes. We also quantified the below-ground radial O2 loss from roots (~1 mm from the root-apex to elucidate how this below-ground oxic microzone was affected by the presence of epiphytes.Epiphyte-cover on seagrass leaves (~21% areal cover resulted in reduced light quality and quantity for photosynthesis, thus leading to reduced plant fitness. A ~4 times thicker diffusive boundary layer around leaves with epiphyte-cover impeded gas (and nutrient exchange with the surrounding water-column and thus the amount of O2 passively diffusing into the leaves in darkness. During light exposure of the leaves, radial oxygen loss from the below-ground tissue was ~2 times higher from plants without epiphyte-cover. In contrast, no O2 was detectable at the surface of the root-cap tissue of plants with epiphyte-cover during darkness, leaving the plants more susceptible to sulphide intrusion.Epiphyte growth on seagrass leaves thus negatively affects the light climate and O2 uptake in darkness, hampering the plants performance and thereby reducing the oxidation capability of its below-ground tissue.

  17. Process of the x-ray image formation, (2). The limit to recognize a simple figure, (2)

    Energy Technology Data Exchange (ETDEWEB)

    Mitsuta, H [Osaka City Univ. (Japan). Hospital

    1980-03-01

    In recent year, X-ray photographs can be obtained by very low dose with high sensitivity photographic system. Such very low dose makes the image quality inferior because of the fluctuation of X-ray quanta so called ''quantum noise''. The process of the X-ray image formation was evaluated from a point of view that the X-ray images are formed by the accumulation of X-ray quanta distributed randomly. And the condition that the image of a simple-shaped small object can be recognized into background quanta was investigated. Under the assumption that the quanta absorbed by an object are N sub(s) and that the average number of background quanta per area which is in the same projected area of the object is N sub(b), the condition that N sub(s) is recognizable in background is mathematically led to the following formula: N sub(s) > 4(..sqrt..N sub(b) + 1). Then the validity of this formula was experimentally shown using a computer and a simulation system by a gamma camera.

  18. Disentangling above- and below-ground competition between lianas and trees in a tropical forest

    NARCIS (Netherlands)

    Schnitzer, S.A.; Kuzee, M.E.; Bongers, F.J.J.M.

    2005-01-01

    1 Light is thought to be the most limiting resource in tropical forests, and thus aboveground competition is commonly accepted as the mechanism that structures these communities. In many tropical forests, trees compete not only with other trees, but also with lianas, which compete aggressively for

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

    NARCIS (Netherlands)

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

    2013-01-01

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

  20. Aboveground and belowground mammalian herbivores regulate the demography of deciduous woody species in conifer forests

    Science.gov (United States)

    Bryan A. Endress; Bridgett J. Naylor; Burak K. Pekin; Michael J. Wisdom

    2016-01-01

    Mammalian herbivory can have profound impacts on plant population and community dynamics. However, our understanding of specific herbivore effects remains limited, even in regions with high densities of domestic and wild herbivores, such as the semiarid conifer forests of western North America. We conducted a seven-year manipulative experiment to evaluate the effects...

  1. Disentangling above- and below-ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat.

    Science.gov (United States)

    Lozano, Yudi M; Armas, Cristina; Hortal, Sara; Casanoves, Fernando; Pugnaire, Francisco I

    2017-12-01

    Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an important role, but an analysis to disentangle the effects of soil microorganisms, soil properties and microclimate on facilitation is lacking. In three microhabitats (gaps, small and large Retama shrubs), we placed six microcosms with sterilized soil, two per soil origin (i.e. from each microhabitat). One in every pair received an alive, and the other a sterile, inoculum from its own soil. Seeds of annual plants were sown into the microcosms. Germination, survival and biomass were monitored. Soil bacterial communities were characterized by pyrosequencing. Germination in living Retama inoculum was nearly double that of germination in sterile inoculum. Germination was greater under Retama canopies than in gaps. Biomass was up to three times higher in nurse than in gap soils. Soil microorganisms, soil properties and microclimate showed a range of positive to negative effects on understory plants depending on species identity and life stage. Nurse soil microorganisms promoted germination, but the effect was smaller than the positive effects of soil properties and microclimate under nurses. Nurse below-ground environment (soil properties and microorganisms) promoted plant growth and survival more than nurse microhabitat. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  2. Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host-parasite interactions.

    Science.gov (United States)

    Tao, Leiling; Gowler, Camden D; Ahmad, Aamina; Hunter, Mark D; de Roode, Jacobus C

    2015-10-22

    Host-parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host-parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host-parasite systems. © 2015 The Author(s).

  3. Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host–parasite interactions

    Science.gov (United States)

    Tao, Leiling; Gowler, Camden D.; Ahmad, Aamina; Hunter, Mark D.; de Roode, Jacobus C.

    2015-01-01

    Host–parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host–parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host–parasite systems. PMID:26468247

  4. Mapping the above and belowground biomass in three landscapes in Cameroon, Rwanda and DRC: pilot cases in REDD+ pilot project.

    Science.gov (United States)

    Sufo Kankeu, R.

    2017-12-01

    A number of biomass/carbon maps have been recently produced using different approaches and despite their comparison there is still a gap. To fill this gap there is a need to provide accurate maps based on the field data on all types of land use and land cover. Based on the field data from plots established in three pilot projects around Virunga National park in Rwanda, Tri-national Sangha landscape in Cameroon and lac Télé-Lac Tumba landscape in DRC, this paper intend to analyse the relationship between land use change and biomass and present the variability through biomass/carbon maps. The above and belowground biomass was calculated from 95 nested plots of 20 meters radius. The value of biomass/carbon per plot were thus used to elaborate carbon maps of each study site. In the same the way the correlation between the land use and underground and above ground carbon stock were analysed using geographically weighted regression. These data have been joint with classified Spot 5 image and aggregated to come out will acceptable result. Results show that there is a strong relationship between land use in various project sites and the carbon stock related, the change of a forest cover directly impact on carbon stock/biomass.in the same way carbon map realized base on field data and IDW, Kriging or spline module show an idea on the carbon distribution but the maps are not accurate giving the distance between plots,

  5. A statistical rationale for establishing process quality control limits using fixed sample size, for critical current verification of SSC superconducting wire

    International Nuclear Information System (INIS)

    Pollock, D.A.; Brown, G.; Capone, D.W. II; Christopherson, D.; Seuntjens, J.M.; Woltz, J.

    1992-01-01

    This work has demonstrated the statistical concepts behind the XBAR R method for determining sample limits to verify billet I c performance and process uniformity. Using a preliminary population estimate for μ and σ from a stable production lot of only 5 billets, we have shown that reasonable sensitivity to systematic process drift and random within billet variation may be achieved, by using per billet subgroup sizes of moderate proportions. The effects of subgroup size (n) and sampling risk (α and β) on the calculated control limits have been shown to be important factors that need to be carefully considered when selecting an actual number of measurements to be used per billet, for each supplier process. Given the present method of testing in which individual wire samples are ramped to I c only once, with measurement uncertainty due to repeatability and reproducibility (typically > 1.4%), large subgroups (i.e. >30 per billet) appear to be unnecessary, except as an inspection tool to confirm wire process history for each spool. The introduction of the XBAR R method or a similar Statistical Quality Control procedure is recommend for use in the superconducing wire production program, particularly when the program transitions from requiring tests for all pieces of wire to sampling each production unit

  6. Sorption-desorption processes of radioisotopes with solid materials from liquid releases and atmosphere deposits. The distribution coefficient (Ksub(d)), its uses, limitations, and practical applications

    International Nuclear Information System (INIS)

    Saas, Arsene

    1979-03-01

    The various sorption-desorption processes of radionuclides with environmental materials are presented. The parameters governing the distribution coefficient are reviewed in the light of various examples. The factors affecting equilibria between the different phases are: reaction time, concentration of the solid phase, water quality, salinity, competition between ions, concentration of radioisotopes or stable isotopes, pH of the mobile phase, particle diameter, chemical form of the radioisotopes, nature of the solid phase, temperature. The effects of the biological parameters on the distribution coefficient are discussed. Biological processes affect the main chemical transformations: mineralization, insolubilization, oxidation-reduction, complexation, ... The importance of these processes is demonstrated by a number of examples in various media. Finally, the practical use of Ksub(d) in the assessment of the environmental impact of radioactive releases is developed, with special emphasis on the limits of its use in siting studies and its essential interest in specifying pathways and capacity of a river system [fr

  7. Depression of belowground respiration is more pronounced than enhancement of photosynthesis during the first year after nitrogen fertilization of a mature Pacific Northwest Douglas-fir forest

    Science.gov (United States)

    Chen, B.; Black, T. A.; Jassal, R.; Nesic, Z.; Bruemmer, C.

    2008-05-01

    Nitrogen (N) additions to forest have shown variable effects on both respiration and photosynthesis. With increasing rates of anthropogenic N deposition, there is a strong need to understand the ecosystem response to N inputs. We investigated how N fertilization affects the ecosystem carbon (C) balance of a 57-year-old coast Douglas-fir stand in British Columbia, Canada, based on eddy-covariance (EC) and soil-chamber (fertilized and control plots) measurements and process-based modeling. The stand was fertilized by helicopter with urea at 200 kg N ha-1 in January 2007. A land surface model (Ecosystem Atmosphere Simulation Scheme, EASS) was combined with an ecosystem model (Boreal Ecosystem Productivity Simulator, BEPS) and a coupled C and N subroutine was incorporated into the integrated EASS-BEPS model in this study. This half-hourly time step model was run continuously for the period from 2001 to 2007 in two scenarios: with and without fertilization. Modeled C fluxes without fertilization [net ecosystem productivity (NEP), gross primary productivity (GPP), ecosystem respiration (Re) and belowground respiration (Rs)] agreed well with EC and soil chamber measurements over diurnal, seasonal and annual time scales for 2001 to 2006; while simulated NEP, GPP, Re and Rs with fertilization reasonably followed EC and chamber measurements in 2007 (545 vs. 520, 2163 vs. 2155, 1618 vs. 1635, and 920 vs. 906 g C m-2 yr-1, respectively). Comparison of EC-determined C fluxes in 2007 with model simulations without fertilization suggests that annual Re decreased by 6.7% (1635 vs. 1752 g C m-2), gross primary productivity (GPP) increased by 6.8% (2155 vs. 2017 g C m-2), and annual NEP increased by 96.2% (520 vs. 265 g C m-2) due to fertilization. The modeled reduction in Rs (9.6%, comparing modeled values without and with fertilization: 1008 vs. 920 g C m-2 yr-1) is consistent with that measured using the soil chambers (~11.5%, comparing CO2 effluxes from control and fertilized

  8. Aggravated phosphorus limitation on biomass production under increasing nitrogen loading: a meta-analysis.

    Science.gov (United States)

    Li, Yong; Niu, Shuli; Yu, Guirui

    2016-02-01

    Nitrogen (N) and phosphorus (P), either individually or in combination, have been demonstrated to limit biomass production in terrestrial ecosystems. Field studies have been extensively synthesized to assess global patterns of N impacts on terrestrial ecosystem processes. However, to our knowledge, no synthesis has been done so far to reveal global patterns of P impacts on terrestrial ecosystems, especially under different nitrogen (N) levels. Here, we conducted a meta-analysis of impacts of P addition, either alone or with N addition, on aboveground (AGB) and belowground biomass production (BGB), plant and soil P concentrations, and N : P ratio in terrestrial ecosystems. Overall, our meta-analysis quantitatively confirmed existing notions: (i) colimitation of N and P on biomass production and (ii) more P limitation in tropical forest than other ecosystems. More importantly, our analysis revealed new findings: (i) P limitation on biomass production was aggravated by N enrichment and (ii) plant P concentration was a better indicator of P limitation than soil P availability. Specifically, P addition increased AGB and BGB by 34% and 13%, respectively. The effect size of P addition on biomass production was larger in tropical forest than grassland, wetland, and tundra and varied with P fertilizer forms, P addition rates, or experimental durations. The P-induced increase in biomass production and plant P concentration was larger under elevated than ambient N. Our findings suggest that the global limitation of P on biomass production will become severer under increasing N fertilizer and deposition in the future. © 2015 John Wiley & Sons Ltd.

  9. Integrating Gene Correction in the Reprogramming and Transdifferentiation Processes: A One-Step Strategy to Overcome Stem Cell-Based Gene Therapy Limitations

    Directory of Open Access Journals (Sweden)

    Seo-Young Lee

    2016-01-01

    Full Text Available The recent advent of induced pluripotent stem cells (iPSCs and gene therapy tools has raised the possibility of autologous cell therapy for rare genetic diseases. However, cellular reprogramming is inefficient in certain diseases such as ataxia telangiectasia, Fanconi anemia, LIG4 syndrome, and fibrodysplasia ossificans progressiva syndrome, owing to interference of the disease-related genes. To overcome these therapeutic limitations, it is necessary to fundamentally correct the abnormal gene during or prior to the reprogramming process. In addition, as genetic etiology of Parkinson’s disease, it has been well known that induced neural stem cells (iNSCs were progressively depleted by LRRK2 gene mutation, LRRK2 (G2019S. Thus, to maintain the induced NSCs directly derived from PD patient cells harboring LRRK2 (G2019S, it would be ideal to simultaneously treat the LRRK2 (G2019S fibroblast during the process of TD. Therefore, simultaneous reprogramming (or TD and gene therapy would provide the solution for therapeutic limitation caused by vulnerability of reprogramming or TD, in addition to being suitable for general application to the generation of autologous cell-therapy products for patients with genetic defects, thereby obviating the need for the arduous processes currently required.

  10. Um índice de capacidade para especificações unilaterais Process capability index for one-sided specification limit

    Directory of Open Access Journals (Sweden)

    Gladys D. Cacsire Barriga

    2003-01-01

    Full Text Available Nos últimos anos, índices de capacidade de processos têm sido usados freqüentemente para determinar se um processo é capaz de produzir itens em conformidade com a tolerância especificada. No entanto, poucos estudos têm sido feitos acerca de índices de capacidade para situações em que há apenas um limite de especificação. Neste trabalho, um índice para situações em que há apenas um limite de especificação é apresentado. Ele é invariante com respeito à fração não-conforme do processo e "calibrado" pelo índice Cpk,. São desenvolvidos também aspectos inferenciais, do ponto de vista bayesiano, para amostragem binomial.Process capability indices have become popular tools to describe how well a process can meet specified tolerances. However, little attention has been given to the study of these indices when the specified tolerances are one-sided. In this work we present an index for such situations. The proposed index is invariant with respect to process fraction non-conforming and it is "Cpk calibrated". Bayesian inference procedure under a binomial sampling is also developed and described for the proposed index.

  11. Recent developments and emergent challenges in Ecohydrology: Focus on the belowground frontier

    Science.gov (United States)

    Mackay, D. S.

    2017-12-01

    The broad spectrum of ecohydrology issues touch on many areas of research in hydrology. But what are the emerging themes and challenges that represent the core of ecohydrology as a maturing discipline? To answer this question the ecohydrology lens was applied to manuscripts published in Water Resources Research over period of 2015 through July 2017. The 235 manuscripts retrieved can be broadly grouped into catchment hydrology, riparian-hyporheic-stream processes, critical zone, land-atmosphere exchange, wetlands, and sustainability. Three dominant crosscutting themes (i.e., coevolution, interfaces, and energy exchange) account for more than half the papers retrieved. In the context of ecohydrology, coevolution refers to the development of physical systems in concert with biological systems and their interactions. In an ecohydrology context, interfaces refer to subsurface, and sometime surface connections that influence transport (e.g., solutes concentration-discharge) influenced by vegetative plumbing, ecophysiology, animal behavior, and microbial processes. Energy exchange in ecohydrology connects vegetative processes to movement of water to the atmosphere through evapotranspiration. Across these themes there is emerging theory and methodology that emphasizes the integrated roles of biology and hydrology in the subsurface. In particular, there is a notable surge of interest in the role of plant roots on subsurface processes. But these are hard to observe and remain challenging to model. By adopting principles of coevolution, in particular, significant advances will be made in modeling plant roots and their depths, corroborated with new geophysical and tracer tools, for improving understanding of critical zone development, subsurface flow processes, and land-atmosphere energy exchange.

  12. Enhancement of laser-induced breakdown spectroscopy (LIBS) Detection limit using a low-pressure and short-pulse laser-induced plasma process.

    Science.gov (United States)

    Wang, Zhen Zhen; Deguchi, Yoshihiro; Kuwahara, Masakazu; Yan, Jun Jie; Liu, Ji Ping

    2013-11-01

    Laser-induced breakdown spectroscopy (LIBS) technology is an appealing technique compared with many other types of elemental analysis because of the fast response, high sensitivity, real-time, and noncontact features. One of the challenging targets of LIBS is the enhancement of the detection limit. In this study, the detection limit of gas-phase LIBS analysis has been improved by controlling the pressure and laser pulse width. In order to verify this method, low-pressure gas plasma was induced using nanosecond and picosecond lasers. The method was applied to the detection of Hg. The emission intensity ratio of the Hg atom to NO (IHg/INO) was analyzed to evaluate the LIBS detection limit because the NO emission (interference signal) was formed during the plasma generation and cooling process of N2 and O2 in the air. It was demonstrated that the enhancement of IHg/INO arose by decreasing the pressure to a few kilopascals, and the IHg/INO of the picosecond breakdown was always much higher than that of the nanosecond breakdown at low buffer gas pressure. Enhancement of IHg/INO increased more than 10 times at 700 Pa using picosecond laser with 35 ps pulse width. The detection limit was enhanced to 0.03 ppm (parts per million). We also saw that the spectra from the center and edge parts of plasma showed different features. Comparing the central spectra with the edge spectra, IHg/INO of the edge spectra was higher than that of the central spectra using the picosecond laser breakdown process.

  13. Inappropriate Use of the Quasi-Reversible Electrode Kinetic Model in Simulation-Experiment Comparisons of Voltammetric Processes That Approach the Reversible Limit

    KAUST Repository

    Simonov, Alexandr N.; Morris, Graham P.; Mashkina, Elena A.; Bethwaite, Blair; Gillow, Kathryn; Baker, Ruth E.; Gavaghan, David J.; Bond, Alan M.

    2014-01-01

    Many electrode processes that approach the "reversible" (infinitely fast) limit under voltammetric conditions have been inappropriately analyzed by comparison of experimental data and theory derived from the "quasi-reversible" model. Simulations based on "reversible" and "quasi-reversible" models have been fitted to an extensive series of a.c. voltammetric experiments undertaken at macrodisk glassy carbon (GC) electrodes for oxidation of ferrocene (Fc0/+) in CH3CN (0.10 M (n-Bu)4NPF6) and reduction of [Ru(NH 3)6]3+ and [Fe(CN)6]3- in 1 M KCl aqueous electrolyte. The confidence with which parameters such as standard formal potential (E0), heterogeneous electron transfer rate constant at E0 (k0), charge transfer coefficient (α), uncompensated resistance (Ru), and double layer capacitance (CDL) can be reported using the "quasi- reversible" model has been assessed using bootstrapping and parameter sweep (contour plot) techniques. Underparameterization, such as that which occurs when modeling CDL with a potential independent value, results in a less than optimal level of experiment-theory agreement. Overparameterization may improve the agreement but easily results in generation of physically meaningful but incorrect values of the recovered parameters, as is the case with the very fast Fc0/+ and [Ru(NH3)6]3+/2+ processes. In summary, for fast electrode kinetics approaching the "reversible" limit, it is recommended that the "reversible" model be used for theory-experiment comparisons with only E0, R u, and CDL being quantified and a lower limit of k 0 being reported; e.g., k0 ≥ 9 cm s-1 for the Fc0/+ process. © 2014 American Chemical Society.

  14. Inappropriate Use of the Quasi-Reversible Electrode Kinetic Model in Simulation-Experiment Comparisons of Voltammetric Processes That Approach the Reversible Limit

    KAUST Repository

    Simonov, Alexandr N.

    2014-08-19

    Many electrode processes that approach the "reversible" (infinitely fast) limit under voltammetric conditions have been inappropriately analyzed by comparison of experimental data and theory derived from the "quasi-reversible" model. Simulations based on "reversible" and "quasi-reversible" models have been fitted to an extensive series of a.c. voltammetric experiments undertaken at macrodisk glassy carbon (GC) electrodes for oxidation of ferrocene (Fc0/+) in CH3CN (0.10 M (n-Bu)4NPF6) and reduction of [Ru(NH 3)6]3+ and [Fe(CN)6]3- in 1 M KCl aqueous electrolyte. The confidence with which parameters such as standard formal potential (E0), heterogeneous electron transfer rate constant at E0 (k0), charge transfer coefficient (α), uncompensated resistance (Ru), and double layer capacitance (CDL) can be reported using the "quasi- reversible" model has been assessed using bootstrapping and parameter sweep (contour plot) techniques. Underparameterization, such as that which occurs when modeling CDL with a potential independent value, results in a less than optimal level of experiment-theory agreement. Overparameterization may improve the agreement but easily results in generation of physically meaningful but incorrect values of the recovered parameters, as is the case with the very fast Fc0/+ and [Ru(NH3)6]3+/2+ processes. In summary, for fast electrode kinetics approaching the "reversible" limit, it is recommended that the "reversible" model be used for theory-experiment comparisons with only E0, R u, and CDL being quantified and a lower limit of k 0 being reported; e.g., k0 ≥ 9 cm s-1 for the Fc0/+ process. © 2014 American Chemical Society.

  15. Inappropriate use of the quasi-reversible electrode kinetic model in simulation-experiment comparisons of voltammetric processes that approach the reversible limit.

    Science.gov (United States)

    Simonov, Alexandr N; Morris, Graham P; Mashkina, Elena A; Bethwaite, Blair; Gillow, Kathryn; Baker, Ruth E; Gavaghan, David J; Bond, Alan M

    2014-08-19

    Many electrode processes that approach the "reversible" (infinitely fast) limit under voltammetric conditions have been inappropriately analyzed by comparison of experimental data and theory derived from the "quasi-reversible" model. Simulations based on "reversible" and "quasi-reversible" models have been fitted to an extensive series of a.c. voltammetric experiments undertaken at macrodisk glassy carbon (GC) electrodes for oxidation of ferrocene (Fc(0/+)) in CH3CN (0.10 M (n-Bu)4NPF6) and reduction of [Ru(NH3)6](3+) and [Fe(CN)6](3-) in 1 M KCl aqueous electrolyte. The confidence with which parameters such as standard formal potential (E(0)), heterogeneous electron transfer rate constant at E(0) (k(0)), charge transfer coefficient (α), uncompensated resistance (Ru), and double layer capacitance (CDL) can be reported using the "quasi-reversible" model has been assessed using bootstrapping and parameter sweep (contour plot) techniques. Underparameterization, such as that which occurs when modeling CDL with a potential independent value, results in a less than optimal level of experiment-theory agreement. Overparameterization may improve the agreement but easily results in generation of physically meaningful but incorrect values of the recovered parameters, as is the case with the very fast Fc(0/+) and [Ru(NH3)6](3+/2+) processes. In summary, for fast electrode kinetics approaching the "reversible" limit, it is recommended that the "reversible" model be used for theory-experiment comparisons with only E(0), Ru, and CDL being quantified and a lower limit of k(0) being reported; e.g., k(0) ≥ 9 cm s(-1) for the Fc(0/+) process.

  16. Development of allometric models for above and belowground biomass in swidden cultivation fallows of Northern Laos

    DEFF Research Database (Denmark)

    McNicol, Iain M.; Berry, Nicholas J.; Bruun, Thilde Bech

    2015-01-01

    fields and patches of mature forest. Quantifying tree biomass in these landscapes is limited by the availability of reliable allometric models, hindering accurate carbon stock estimation and thus quantification of GHG emission associated with land use transitions. We therefore developed new allometric...... for each tree type. Thus, we suggest that field efforts should be directed towards checking resprouting status over the estimation of tree height. We also found that models fit using non-linear regression provided equally good fits to the data compared to the traditional approach of log......-transforming the data. Our models were subsequently applied to 12 nearby plots spanning a chronosequence of fallows to examine the impact of re-sprouting allometry on biomass estimation. Root biomass stocks were on average 58% higher after accounting for the allometry of resprouting trees, resulting in an average 9...

  17. Above- and below-ground effects of plant diversity depend on species origin

    DEFF Research Database (Denmark)

    Kuebbing, Sara E.; Classen, Aimee Taylor; Sanders, Nate

    2015-01-01

    -interaction models to describe how species' interactions influenced diversity-productivity relationships. Communities with more species had higher total biomass than did monoculture communities, but native and nonnative communities diverged in root : shoot ratios and the mechanism responsible for increased......Although many plant communities are invaded by multiple nonnative species, we have limited information on how a species' origin affects ecosystem function. We tested how differences in species richness and origin affect productivity and seedling establishment. We created phylogenetically paired...... native and nonnative plant communities in a glasshouse experiment to test diversity-productivity relationships and responsible mechanisms (i.e. selection or complementarity effects). Additionally, we tested how productivity and associated mechanisms influenced seedling establishment. We used diversity...

  18. Links between plant litter chemistry, species diversity, and below-ground ecosystem function

    OpenAIRE

    Meier, Courtney L.; Bowman, William D.

    2008-01-01

    Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics...

  19. Aboveground and belowground biomass allocation in native Prosopis caldenia Burkart secondaries woodlands in the semi-arid Argentinean pampas

    International Nuclear Information System (INIS)

    Risio, Lucia; Herrero, Celia; Bogino, Stella M.; Bravo, Felipe

    2014-01-01

    The woodlands in the south-west of the Argentinean pampas are dominated by Prosopis Caldenia Burkart (calden). The current deforestation rate of this woodlands is 0.82% per year. Different compensation initiatives have begun that recognize the role of forests as environmental service providers. The financial incentives they offer make it necessary to quantify the amount of carbon stored in the forest biomass. A model for estimating calden biomass was developed. Thirty-eight trees were selected, felled and divided into sections. An equation system was fitted using joint generalized regression to ensure the additivity property. A weighted regression was used to avoid heteroscedasticity. In these woodlands fire is the main disturbance and it can modify tree allometry, due this all models included the area of the base of the stem and tree height as independent variables since it indirectly collects this variability. Total biomass and the stem fraction had the highest R2 A dj. values (0.75), while branches with a diameter less than 7 cm had the lowest (0.58). Tree biomass was also analyzed by partitioning into the basic fractions of stem, crown, roots, and the root/shoot ratio. Biomass allocation was greatest in the crown fraction and the mean root/shoot ratio was 0.58. The carbon stock of the caldenales considering only calden tree biomass is 20.2 Mg ha −1 . While the overall carbon balance of the region is negative (deforestation and biomass burning, the remnant forested area has increased their calden density and in an indirect way his carbon sequestration capacity could also be increased. - Highlights: • A model for estimating aboveground and belowground Prosopis caldenia biomass was developed. • Biomass allocation into the tree and the root/shoot ratio were analyzed. • The equation systems presented had made it possible to more accurately estimate the biomass stored in calden woodlands

  20. Total belowground carbon flux in subalpine forests is related to leaf area index, soil nitrogen, and tree height

    Science.gov (United States)

    Berryman, Erin Michele; Ryan, Michael G.; Bradford, John B.; Hawbaker, Todd J.; Birdsey, R.

    2016-01-01

    In forests, total belowground carbon (C) flux (TBCF) is a large component of the C budget and represents a critical pathway for delivery of plant C to soil. Reducing uncertainty around regional estimates of forest C cycling may be aided by incorporating knowledge of controls over soil respiration and TBCF. Photosynthesis, and presumably TBCF, declines with advancing tree size and age, and photosynthesis increases yet C partitioning to TBCF decreases in response to high soil fertility. We hypothesized that these causal relationships would result in predictable patterns of TBCF, and partitioning of C to TBCF, with natural variability in leaf area index (LAI), soil nitrogen (N), and tree height in subalpine forests in the Rocky Mountains, USA. Using three consecutive years of soil respiration data collected from 22 0.38-ha locations across three 1-km2 subalpine forested landscapes, we tested three hypotheses: (1) annual soil respiration and TBCF will show a hump-shaped relationship with LAI; (2) variability in TBCF unexplained by LAI will be related to soil nitrogen (N); and (3) partitioning of C to TBCF (relative to woody growth) will decline with increasing soil N and tree height. We found partial support for Hypothesis 1 and full support for Hypotheses 2 and 3. TBCF, but not soil respiration, was explained by LAI and soil N patterns (r2 = 0.49), and the ratio of annual TBCF to TBCF plus aboveground net primary productivity (ANPP) was related to soil N and tree height (r2 = 0.72). Thus, forest C partitioning to TBCF can vary even within the same forest type and region, and approaches that assume a constant fraction of TBCF relative to ANPP may be missing some of this variability. These relationships can aid with estimates of forest soil respiration and TBCF across landscapes, using spatially explicit forest data such as national inventories or remotely sensed data products.

  1. Effects of Manipulated Above- and Belowground Organic Matter Input on Soil Respiration in a Chinese Pine Plantation

    Science.gov (United States)

    Zhao, Bo; Wu, Lianhai; Zhang, Chunyu; Zhao, Xiuhai; Gadow, Klaus v.

    2015-01-01

    Alteration in the amount of soil organic matter input can have profound effect on carbon dynamics in forest soils. The objective of our research was to determine the response in soil respiration to above- and belowground organic matter manipulation in a Chinese pine (Pinus tabulaeformis) plantation. Five organic matter treatments were applied during a 2-year experiment: both litter removal and root trenching (LRRT), only litter removal (LR), control (CK), only root trenching (RT) and litter addition (LA). We found that either aboveground litter removal or root trenching decreased soil respiration. On average, soil respiration rate was significantly decreased in the LRRT treatment, by about 38.93% ± 2.01% compared to the control. Soil respiration rate in the LR treatment was 30.65% ± 1.87% and in the RT treatment 17.65% ± 1.95% lower than in the control. Litter addition significantly increased soil respiration rate by about 25.82% ± 2.44% compared to the control. Soil temperature and soil moisture were the main factors affecting seasonal variation in soil respiration. Up to the 59.7% to 82.9% seasonal variation in soil respiration is explained by integrating soil temperature and soil moisture within each of the various organic matter treatments. The temperature sensitivity parameter, Q 10, was higher in the RT (2.72) and LA (3.19) treatments relative to the control (2.51), but lower in the LRRT (1.52) and LR treatments (1.36). Our data suggest that manipulation of soil organic matter input can not only alter soil CO2 efflux, but also have profound effect on the temperature sensitivity of organic carbon decomposition in a temperate pine forest. PMID:25970791

  2. Contrasting above- and belowground organic matter decomposition and carbon and nitrogen dynamics in response to warming in High Arctic tundra.

    Science.gov (United States)

    Blok, Daan; Faucherre, Samuel; Banyasz, Imre; Rinnan, Riikka; Michelsen, Anders; Elberling, Bo

    2017-12-13

    Tundra regions are projected to warm rapidly during the coming decades. The tundra biome holds the largest terrestrial carbon pool, largely contained in frozen permafrost soils. With warming, these permafrost soils may thaw and become available for microbial decomposition, potentially providing a positive feedback to global warming. Warming may directly stimulate microbial metabolism but may also indirectly stimulate organic matter turnover through increased plant productivity by soil priming from root exudates and accelerated litter turnover rates. Here, we assess the impacts of experimental warming on turnover rates of leaf litter, active layer soil and thawed permafrost sediment in two high-arctic tundra heath sites in NE-Greenland, either dominated by evergreen or deciduous shrubs. We incubated shrub leaf litter on the surface of control and warmed plots for 1 and 2 years. Active layer soil was collected from the plots to assess the effects of 8 years of field warming on soil carbon stocks. Finally, we incubated open cores filled with newly thawed permafrost soil for 2 years in the active layer of the same plots. After field incubation, we measured basal respiration rates of recovered thawed permafrost cores in the lab. Warming significantly reduced litter mass loss by 26% after 1 year incubation, but differences in litter mass loss among treatments disappeared after 2 years incubation. Warming also reduced litter nitrogen mineralization and decreased the litter carbon to nitrogen ratio. Active layer soil carbon stocks were reduced 15% by warming, while soil dissolved nitrogen was reduced by half in warmed plots. Warming had a positive legacy effect on carbon turnover rates in thawed permafrost cores, with 10% higher respiration rates measured in cores from warmed plots. These results demonstrate that warming may have contrasting effects on above- and belowground tundra carbon turnover, possibly governed by microbial resource availability. © 2017 John

  3. Anaerobic digestion of thermal pre-treated emulsified slaughterhouse wastes (TESW): Effect of trace element limitation on process efficiency and sludge metabolic properties.

    Science.gov (United States)

    Eftaxias, Alexandros; Diamantis, Vasileios; Aivasidis, Alexandros

    2018-06-01

    Slaughterhouse solid wastes, characterized by a high lipid content, are considered a valuable resource for energy production by means of anaerobic digestion technologies. Aim of this study was to examine the effect of trace element limitation on the mesophilic anaerobic digestion of thermally pre-treated emulsified slaughterhouse wastes (TESW). Under two distinct experimental periods (Period I - low and Period II - high trace element dosage respectively) a CSTR with sludge recirculation was operated at increasing organic loading rate (OLR) from 1.5 to 10 g L -1  d -1 . Under optimum conditions, COD removal was higher than 96%, biogas yield equal to 0.53 L g -1  COD feed and the biogas methane content 77%. Trace element limitation however, resulted in a dramatic decline in process efficiency, with VFA accumulation and events of extreme sludge flotation, despite that the soluble concentration of Ni, Co and Mo were between 12 and 28 μg L -1 . This is indicative of mass transfer limitations caused by lipids adsorption onto the anaerobic biomass. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Belowground biotic complexity drives aboveground dynamics: a test of the soil community feedback model.

    Science.gov (United States)

    Pendergast, Thomas H; Burke, David J; Carson, Walter P

    2013-03-01

    Feedbacks between soil communities and plants may determine abundance and diversity in plant communities by influencing fitness and competitive outcomes. We tested the core hypotheses of soil community feedback theory: plant species culture distinct soil communities that alter plant performance and the outcome of interspecific competition. We applied this framework to inform the repeated dominance of Solidago canadensis in old-field communities. In glasshouse experiments, we examined the effects of soil communities on four plant species' performance in monoculture and outcomes of interspecific competition. We used terminal restriction fragment length polymorphism (TRFLP) analysis to infer differences in the soil communities associated with these plant species. Soil community origin had strong effects on plant performance, changed the intensity of interspecific competition and even reversed whether plant species were limited by conspecifics or heterospecifics. These plant-soil feedbacks are strong enough to upend winners and losers in classic competition models. Plant species cultured significantly different mycorrhizal fungal and bacterial soil communities, indicating that these feedbacks are likely microbiotic in nature. In old-fields and other plant communities, these soil feedbacks appear common, fundamentally alter the intensity and nature of plant competition and potentially maintain diversity while facilitating the dominance of So. canadensis. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  5. Evaluation of limiting factors affecting photovoltaic performance of low-temperature-processed TiO₂ films in dye-sensitized solar cells.

    Science.gov (United States)

    Lee, Taek-Yong; Kim, Hui-Seon; Park, Nam-Gyu

    2014-04-14

    Limiting factors affecting photovoltaic performance of dye-sensitized solar cell employing low-temperature-processed TiO2 films were investigated. TiO2 films were prepared at a low temperature of 200 °C using the normal alcohol-containing binder-free TiO2 paste (LT200). Their photovoltaic performance was compared to a high-temperature (550 °C) annealed TiO2 film prepared using a polymer binder containing TiO2 paste (HT550). Compared to the proportional increase in conversion efficiency with TiO2 film thickness upto 14 μm for HT550, the increase in efficiency was terminated at relatively smaller thickness of about 8 μm for LT200 mainly due to unaugmented photocurrent. From the transient photocurrent-voltage studies, the electron transport rate was found to be almost identical, while charge recombination was one order of magnitude faster for LT200. Consequently, the electron diffusion length was more than 2-3 times shorter for LT200 than for HT550. Electron diffusion length and electron life time obtained from electrochemical impedance analysis were well consistent with those observed from transient measurement. Density of states (DOS) was evaluated to be shallow and narrow in LT200, which was responsible for limiting photovoltaic performance in the low-temperature processed TiO2 film. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Simultaneous exposure of nematophagous fungi, entomopathogenic nematodes and entomopathogenic fungi can modulate belowground insect pest control.

    Science.gov (United States)

    Bueno-Pallero, Francisco Ángel; Blanco-Pérez, Rubén; Dionísio, Lídia; Campos-Herrera, Raquel

    2018-05-01

    Entomopathogenic nematodes (EPNs) and fungi (EPF) are well known biological control agents (BCAs) against insect pests. Similarly, the nematophagous fungi (NF) are considered good BCA candidates for controlling plant parasitic nematodes. Because NF can employ EPNs as food and interact with EPF, we speculate that the simultaneous application of EPNs and EPF might result in higher insect mortality, whereas the triple species combination with NF will reduce the EPN and EPF activity by predation or inhibition. Here we evaluated single, dual (EPN + EPF, EPF + NF, EPN + NF) and triple (EPN + EPF + NF) combinations of one EPN, Steinernema feltiae (Rhabditida: Steinernematidae), one EPF, Beauveria bassiana (Hypocreales: Clavicipitaceae), and two NF, Arthrobotrys musiformis (Orbiliales: Orbiliaceae) and Purpureocillium lilacinum (Hypocreales: Ophiocordycipitaceae) under laboratory conditions. First, we showed that EPF reduced the growth rate of NF and vice versa when combined in both rich and limiting media, suggesting a negative interaction when combining both fungi. Three different fungal applications (contact with mycelia-conidia, immersion in conidial suspension, and injection of conidial suspension) were tested in single, dual and triple species combinations, evaluating Galleria mellonella (Lepidoptera: Pyralidae) larval mortality and time to kill. When mycelia was presented, the EPF appeared to be the dominant in combined treatments, whereas in immersion exposure was the EPN. In both types of exposure, NF alone did not produce any effect on larvae. However, when A. musiformis was injected, it produced larval mortalities >70% in the same time span as EPN. Overall, additive effects dominated the dual and triple combinations, with the exception of injection method, where synergisms occurred for both NF species combined with EPN + EPF. This study illustrates how differences in species combination and timing of fungal arrival can modulate the action

  7. Contribution to the identification of the processes kinetically limiting of the zirconium alloys oxidation; characterization of the oxide films formed at high temperature by solids electrochemistry

    International Nuclear Information System (INIS)

    Vermoyal, J.J.

    2000-06-01

    The corrosion behavior of zirconium alloys used for cladding tubes has been extensively studied under several oxidation conditions (temperature, steam, dry air, oxygen...) in order to clarify the mechanism(s) of oxide growth and breakdown. Oxidation rate is generally assumed to be controlled by oxygen diffusion inwards the oxide layer. Nevertheless, several experimental facts, such as acceleration or inhibition of corrosion rate in coupling conditions, suggest that electrochemical processes are involved as a rate determining step. This work is an attempt to shed light about the rate-limiting-mechanism of two zirconium alloys oxidation: Zircaloy-4 (Zy-4) and Zr-Nb(1%)O(0,13%). Impedance spectroscopy characterizations of oxide films formed in high temperature water and studied in gaseous atmosphere clearly show the difference of electrical properties between the two alloys. The in situ electrochemical and thermogravimetric investigations in gaseous medium, and the polarization effects on oxidation and hydridation of Zr alloys in PWRs conditions indicate that oxygen diffusion can be considered as the limiting kinetic step for Zy-4 oxidation. On the contrary, the acceleration of oxide growth on Zr-Nb(1%)O(0,13%) under anodic polarization in PWRs conditions (360 deg C) suggests that either the electronic conductivity in the oxide or an interfacial process at least partially control the oxidation rate. Catalytic effects observed in gaseous medium when noble metals increase the oxygen reduction rate would tend to corroborate the oxidation control of this alloy by an interfacial mechanism. An electrochemical description and a heterogeneous kinetics approach based on a diffusion-interfacial process as rate determining step are then proposed. (author)

  8. Effects of elevated temperature and CO2 on aboveground-belowground systems: a case study with plants, their mutualistic bacteria and root / shoot herbivores

    Directory of Open Access Journals (Sweden)

    James Michael William Ryalls

    2013-11-01

    Full Text Available Interactions between above- and belowground herbivores have been prominent in the field of aboveground-belowground ecology from the outset, although little is known about how climate change affects these organisms when they share the same plant. Additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (eT and elevated atmospheric carbon dioxide (eCO2 are untested. We investigated how eT and eCO2 affected larval development of the lucerne weevil (Sitona discoideus and colonisation by the pea aphid (Acyrthosiphon pisum, on three cultivars of a common host plant, lucerne (Medicago sativa. Sitona discoideus larvae feed on root nodules housing N2-fixing rhizobial bacteria, allowing us to test the effects of eT and eCO2 on three trophic levels. Moreover, we assessed the influence of these factors on plant growth. eT increased plant growth rate initially (6, 8 and 10 weeks after sowing, with cultivar ‘Sequel’ achieving the greatest height. Inoculation with aphids, however, reduced plant growth at week 14. eT severely reduced root nodulation by 43%, whereas eCO2 promoted nodulation by 56%, but only at ambient temperatures. Weevil presence increased net root biomass and nodulation, by 31 and 45%, respectively, showing an overcompensatory plant growth response. Effects of eT and eCO2 on root nodulation were mirrored by weevil larval development; eT and eCO2 reduced and increased larval development, respectively. Contrary to expectations, aphid colonisation was unaffected by eT or eCO2, but there was a near-significant 10% reduction in colonisation rates on plants with weevils present belowground. The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

  9. Process of care and preliminary outcome in limited-stage small-cell lung cancer: results of the 1995-1997 patterns of care study in Japan

    International Nuclear Information System (INIS)

    Uno, Takashi; Sumi, Minako; Sawa, Yoshihide M.S.; Teshima, Teruki; Hara, Ryusuke; Ikeda, Hiroshi; Inoue, Toshihiko

    2003-01-01

    Purpose: To evaluate the practice process using the national average (Na); to compare differences in the process of care by age group; and to provide a preliminary outcome data for limited-stage small-cell lung cancer in Japan. Methods and Materials: The Patterns of Care Study conducted a nationwide survey of the care process for Stage I-III small-cell lung cancer in Japan. Patients were divided into three age groups: <65 years (younger group, n = 73); between 65 and 74 years (intermediate group, n = 81); and ≥75 years (elderly group, n = 20). Results: The NA for the total dose was 49.0 Gy, and for use of photon energy ≥6 MV, chemotherapy, and prophylactic cranial irradiation was 77.3%, 93.2%, and 1.69%, respectively. Age stratification had no impact on the variables of radiotherapy (RT) such as total dose and field size. Only 37% of patients received chemotherapy and thoracic RT concurrently. The proportion of patients who received chemotherapy and RT concurrently was 44%, 27%, and 25% of the younger, intermediate, and elderly groups, respectively (p = 0.029). Etoposide and cisplatin were less frequently used in the elderly group (≥75 years old). Overall survival at 3 years for the entire group was 26%. The 3-year survival rate was 30% in the younger group, 28% in the intermediate group, and 9% in the elderly group. Variables found to have a significant impact on survival by multivariate analysis were the use of chemotherapy (p = 0.030), age (p 0.032), and T stage (p = 0.042). Conclusion: Calculated NAs showed that the results of clinical study had favorably penetrated into the practice process in Japan. The results demonstrated that patient age significantly influenced the process of chemotherapy such as the use of etoposide and cisplatin for limited-stage small-cell lung cancer in Japan. More concurrent chemotherapy and thoracic RT and the application of prophylactic cranial irradiation for complete responders need to be investigated in the future

  10. "I have surly passed a limit, it is simply too much": women's and men's experiences of stress and wellbeing when living within a process of housework resignation.

    Science.gov (United States)

    Harryson, Lisa; Aléx, Lena; Hammarström, Anne

    2016-03-04

    Gender inequality within paid and unpaid work exposes women and men to different environments and responsibilities. These gender patterns shape living conditions for women and men, either negatively or positively, by affecting the prospect of good health. Most public health studies of gender and housework are quantitative, and knowledge about the relationship between housework experiences and health for women and men is limited. The aim of this study was to explore the housework experiences and practices of women and men and their experiences of stress and perceived wellbeing from a gender perspective. We conducted thematic interviews with four women and four men living in Sweden, and performed an analysis using the Grounded Theory method. We found that stereotypical gender practices in housework influenced experiences of stress and perceived wellbeing among women and men. Despite proposing gender equality in housework as a means of improving wellbeing, inequality was amplified by the way women and men handle the gendered division of housework. We call this recurring theme "The process of housework resignation", which also constitute the core category in our analysis. "The process of housework resignation" was theorised from the categories "Gender practices in housework", "Experiencing stress and wellbeing" and "Managing daily life". Stereotypical gender practices in housework can increase experiences of stress among women and men. Challenging stereotypical masculinities can be a key for breaking the process of resignation in housework and for facilitating improved health among both women and men in heterosexual couple relationships within a Swedish context.

  11. Modeling Complex Time Limits

    Directory of Open Access Journals (Sweden)

    Oleg Svatos

    2013-01-01

    Full Text Available In this paper we analyze complexity of time limits we can find especially in regulated processes of public administration. First we review the most popular process modeling languages. There is defined an example scenario based on the current Czech legislature which is then captured in discussed process modeling languages. Analysis shows that the contemporary process modeling languages support capturing of the time limit only partially. This causes troubles to analysts and unnecessary complexity of the models. Upon unsatisfying results of the contemporary process modeling languages we analyze the complexity of the time limits in greater detail and outline lifecycles of a time limit using the multiple dynamic generalizations pattern. As an alternative to the popular process modeling languages there is presented PSD process modeling language, which supports the defined lifecycles of a time limit natively and therefore allows keeping the models simple and easy to understand.

  12. Long-term operation of oxygen-limiting membrane bioreactor (MBR) for the development of simultaneous partial nitrification, anammox and denitrification (SNAD) process.

    Science.gov (United States)

    Zhao, Chuanqi; Wang, Gang; Xu, Xiaochen; Yang, Yuesuo; Yang, Fenglin

    2017-07-18

    In this study, an oxygen-limiting membrane bioreactor (MBR) with recirculation of biogas for relieving membrane fouling was successfully operated to realize the simultaneous partial nitrification, anammox and denitrification (SNAD) process. The MBR operation was considered effective in the long-term test with total nitrogen (TN) and chemical oxygen demand (COD) removal efficiencies of 94.86% and 98.91%, respectively. Membrane fouling was significantly alleviated due to the recirculation of biogas and the membrane had been cleaned four times with a normal filtration period of 52 days. The co-existence of ammonia-oxidizing bacteria (AOB), anammox and denitrifying bacteria in MBR was confirmed by scanning electron microscopy (SEM) and fluorescence in situ hybridizations (FISH) analysis. Furthermore, AOB were found close to the granule surface, while denitrifying bacteria and anammox were in the deeper layer of granules. Potential in excellent TN and COD removal, operational stability and sustainability, as well as in alleviating membrane fouling is expected by using this oxygen-limiting MBR.

  13. Evidence of Facilitation Cascade Processes as Drivers of Successional Patterns of Ecosystem Engineers at the Upper Altitudinal Limit of the Dry Puna.

    Science.gov (United States)

    Malatesta, Luca; Tardella, Federico Maria; Piermarteri, Karina; Catorci, Andrea

    2016-01-01

    Facilitation processes constitute basic elements of vegetation dynamics in harsh systems. Recent studies in tropical alpine environments demonstrated how pioneer plant species defined as "ecosystem engineers" are capable of enhancing landscape-level richness by adding new species to the community through the modification of microhabitats, and also provided hints about the alternation of different ecosystem engineers over time. Nevertheless, most of the existing works analysed different ecosystem engineers separately, without considering the interaction of different ecosystem engineers. Focusing on the altitudinal limit of Peruvian Dry Puna vegetation, we hypothesized that positive interactions structure plant communities by facilitation cascades involving different ecosystem engineers, determining the evolution of the microhabitat patches in terms of abiotic resources and beneficiary species hosted. To analyze successional mechanisms, we used a "space-for-time" substitution to account for changes over time, and analyzed data on soil texture, composition, and temperature, facilitated species and their interaction with nurse species, and surface area of engineered patches by means of chemical analyses, indicator species analysis, and rarefaction curves. A successional process, resulting from the dynamic interaction of different ecosystem engineers, which determined a progressive amelioration of soil conditions (e.g. nitrogen and organic matter content, and temperature), was the main driver of species assemblage at the community scale, enhancing species richness. Cushion plants act as pioneers, by starting the successional processes that continue with shrubs and tussocks. Tussock grasses have sometimes been found to be capable of creating microhabitat patches independently. The dynamics of species assemblage seem to follow the nested assemblage mechanism, in which the first foundation species to colonize a habitat provides a novel substrate for colonization by other

  14. Evidence of Facilitation Cascade Processes as Drivers of Successional Patterns of Ecosystem Engineers at the Upper Altitudinal Limit of the Dry Puna.

    Directory of Open Access Journals (Sweden)

    Luca Malatesta

    Full Text Available Facilitation processes constitute basic elements of vegetation dynamics in harsh systems. Recent studies in tropical alpine environments demonstrated how pioneer plant species defined as "ecosystem engineers" are capable of enhancing landscape-level richness by adding new species to the community through the modification of microhabitats, and also provided hints about the alternation of different ecosystem engineers over time. Nevertheless, most of the existing works analysed different ecosystem engineers separately, without considering the interaction of different ecosystem engineers. Focusing on the altitudinal limit of Peruvian Dry Puna vegetation, we hypothesized that positive interactions structure plant communities by facilitation cascades involving different ecosystem engineers, determining the evolution of the microhabitat patches in terms of abiotic resources and beneficiary species hosted. To analyze successional mechanisms, we used a "space-for-time" substitution to account for changes over time, and analyzed data on soil texture, composition, and temperature, facilitated species and their interaction with nurse species, and surface area of engineered patches by means of chemical analyses, indicator species analysis, and rarefaction curves. A successional process, resulting from the dynamic interaction of different ecosystem engineers, which determined a progressive amelioration of soil conditions (e.g. nitrogen and organic matter content, and temperature, was the main driver of species assemblage at the community scale, enhancing species richness. Cushion plants act as pioneers, by starting the successional processes that continue with shrubs and tussocks. Tussock grasses have sometimes been found to be capable of creating microhabitat patches independently. The dynamics of species assemblage seem to follow the nested assemblage mechanism, in which the first foundation species to colonize a habitat provides a novel substrate for

  15. Production dynamics of fine roots in beech forests: possible mechanism of resource allocation between above- and below-ground production

    Science.gov (United States)

    Nakahata, R.; Osawa, A.; Naramoto, M.; Mizunaga, H.; Sato, M.

    2017-12-01

    The masting phenomenon that seed production has large annual variation with spatial synchrony appears generally in beeches. Therefore, net primary production and carbon allocation mechanism in beech forests may differ among several years in relation to annual variation of seed production. On the other hand, fine roots play key roles in carbon dynamics and nutrient and water acquisition of an ecosystem. Evaluation of fine root dynamics is essential to understand long-term dynamics of production in forest ecosystems. Moreover, the influence of mast seeding on resource allocation should be clarified in such beech forests. The aim of this study is to clarify possible relationships between the patterns of above- and below-ground production in relation to the masting events using observation data of litter fall and fine root dynamics. We applied the litter trap method and a minirhizotron method in a cool-temperate natural forest dominated by beech (Fagus crenata Blume). Ten litter traps were set from 2008 to 2016, then annual leaf and seed production were estimated. Four minirhizotron tubes were buried in Aug. 2008 and soil profiles were scanned monthly until Nov. 2016 during the periods of no snow covering. The scanned soil profiles were analyzed for calculating fine root production using the WinRHIZO Tron software. In the present study site, rich production of mast seeding occurred biennially and fine root production showed various seasonal patterns. There was no significant correlation between seed production and annual fine root production in the same year. However, seed production had a positive correlation with fine root production in autumn in the previous year and indicated a negative correlation with that in autumn in the current year. These results indicate that higher fine root production has led to increased nutrient acquisition, which resulted in rich seed production in the next year. It is also suppressed after the masting events due to shortage in

  16. Comparative Metagenomics Reveal Phylum Level Temporal and Spatial Changes in Mycobiome of Belowground Parts of Crocus sativus.

    Directory of Open Access Journals (Sweden)

    Sheetal Ambardar

    Full Text Available Plant-fungal associations have been explored by routine cultivation based approaches and cultivation based approaches cannot catalogue more than 5% of fungal diversity associated with any niche. In the present study, an attempt has been made to catalogue fungal diversity associated with belowground parts i.e. rhizosphere and cormosphere, of Crocus sativus (an economically important herb during two growth stages, using cultivation independent ITS gene targeted approach, taking bulk soil as reference. The 454 pyrosequencing sequence data analysis suggests that the fungal diversity was niche and growth stage specific. Fungi diversity, in the present case, was not only different between the two organs (roots and corm but the dominance pattern varies between the cormosphere during two growth stages. Zygomycota was dominant fungal phylum in the rhizosphere whereas Basidiomycota was dominant in cormosphere during flowering stage. However in cormosphere though Basidiomycota was dominant phylum during flowering stage but Zygomycota was dominant during dormant stage. Interestingly, in cormosphere, the phyla which was dominant at dormant stage was rare at flowering stage and vice-versa (Basidiomycota: Flowering = 93.2% Dormant = 0.05% and Zygomycota: Flowering = 0.8% Dormant = 99.7%. At genus level, Rhizopus was dominant in dormant stage but was rare in flowering stage (Rhizopus: Dormant = 99.7% Flowering = 0.55%. This dynamics is not followed by the bulk soil fungi which was dominated by Ascomycota during both stages under study. The genus Fusarium, whose species F. oxysporum causes corm rot in C. sativus, was present during both stages with slightly higher abundance in roots. Interestingly, the abundance of Rhizopus varied a great deal in two stages in cormosphere but the abundance of Fusarium was comparable in two growth stages (Bulk soil Flowering = 0.05%, Rhizosphere Flowering = 1.4%, Cormosphere Flowering = 0.06%, Bulk soil Dormant = 2.47% and

  17. Belowground ecology of scarabs feeding on grass roots: current knowledge and future directions for management in Australasia

    Directory of Open Access Journals (Sweden)

    Adam eFrew

    2016-03-01

    Full Text Available Many scarab beetles spend the majority of their lives belowground as larvae, feeding on grass roots. Many of these larvae are significant pests, causing damage to crops and grasslands. Damage by larvae of the greyback cane beetle (Dermolepida albohirtum, for example, can cause financial losses of up to AU$40 million annually to the Australian sugarcane industry. We review the ecology of some scarab larvae in Australasia, focusing on three subfamilies; Dynastinae, Rutelinae and Melolonthinae, containing key pest species. Although considerable research on the control of some scarab pests has been carried out in Australasia, for some species, the basic biology and ecology remains largely unexplored. We synthesize what is known about these scarab larvae and outline key knowledge gaps to highlights future research directions with a view to improve pest management. We do this by presenting an overview of the scarab larval host plants and feeding behavior; the impacts of abiotic (temperature, moisture and fertilization and biotic (pathogens, natural enemies and microbial symbionts factors on scarab larvae and conclude with how abiotic and biotic factors can be applied in agriculture for improved pest management, suggesting future research directions.Several host plant microbial symbionts, such as arbuscular mycorrhizal fungi and endophytes, can improve plant tolerance to scarabs and reduce larval performance, which have shown promise for use in pest management. In addition to this, several microbial scarab pathogens have been isolated for commercial use in pest management with particularly promising results. The entomopathogenic fungus Metarhizium anisopliae caused a 50% reduction in cane beetle larvae while natural enemies such as entomopathogenic nematodes have also shown potential as a biocontrol. Continued research should focus on filling the gaps in the knowledge of the basic ecology and feeding behavior of scarab larval species within Australasia

  18. Recognition of Orobanche cumana Below-Ground Parasitism Through Physiological and Hyper Spectral Measurements in Sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Cochavi, Amnon; Rapaport, Tal; Gendler, Tania; Karnieli, Arnon; Eizenberg, Hanan; Rachmilevitch, Shimon; Ephrath, Jhonathan E

    2017-01-01

    Broomrape ( Orobanche and Phelipanche spp.) parasitism is a severe problem in many crops worldwide, including in the Mediterranean basin. Most of the damage occurs during the sub-soil developmental stage of the parasite, by the time the parasite emerges from the ground, damage to the crop has already been done. One feasible method for sensing early, below-ground parasitism is through physiological measurements, which provide preliminary indications of slight changes in plant vitality and productivity. However, a complete physiological field survey is slow, costly and requires skilled manpower. In recent decades, visible to-shortwave infrared (VIS-SWIR) hyperspectral tools have exhibited great potential for faster, cheaper, simpler and non-destructive tracking of physiological changes. The advantage of VIS-SWIR is even greater when narrow-band signatures are analyzed with an advanced statistical technique, like a partial least squares regression (PLS-R). The technique can pinpoint the most physiologically sensitive wavebands across an entire spectrum, even in the presence of high levels of noise and collinearity. The current study evaluated a method for early detection of Orobanche cumana parasitism in sunflower that combines plant physiology, hyperspectral readings and PLS-R. Seeds of susceptible and resistant O. cumana sunflower varieties were planted in infested (15 mg kg -1 seeds) and non-infested soil. The plants were examined weekly to detect any physiological or structural changes; the examinations were accompanied by hyperspectral readings. During the early stage of the parasitism, significant differences between infected and non-infected sunflower plants were found in the reflectance of near and shortwave infrared areas. Physiological measurements revealed no differences between treatments until O. cumana inflorescences emerged. However, levels of several macro- and microelements tended to decrease during the early stage of O. cumana parasitism. Analysis of

  19. Recognition of Orobanche cumana Below-Ground Parasitism Through Physiological and Hyper Spectral Measurements in Sunflower (Helianthus annuus L.

    Directory of Open Access Journals (Sweden)

    Amnon Cochavi

    2017-06-01

    Full Text Available Broomrape (Orobanche and Phelipanche spp. parasitism is a severe problem in many crops worldwide, including in the Mediterranean basin. Most of the damage occurs during the sub-soil developmental stage of the parasite, by the time the parasite emerges from the ground, damage to the crop has already been done. One feasible method for sensing early, below-ground parasitism is through physiological measurements, which provide preliminary indications of slight changes in plant vitality and productivity. However, a complete physiological field survey is slow, costly and requires skilled manpower. In recent decades, visible to-shortwave infrared (VIS-SWIR hyperspectral tools have exhibited great potential for faster, cheaper, simpler and non-destructive tracking of physiological changes. The advantage of VIS-SWIR is even greater when narrow-band signatures are analyzed with an advanced statistical technique, like a partial least squares regression (PLS-R. The technique can pinpoint the most physiologically sensitive wavebands across an entire spectrum, even in the presence of high levels of noise and collinearity. The current study evaluated a method for early detection of Orobanche cumana parasitism in sunflower that combines plant physiology, hyperspectral readings and PLS-R. Seeds of susceptible and resistant O. cumana sunflower varieties were planted in infested (15 mg kg-1 seeds and non-infested soil. The plants were examined weekly to detect any physiological or structural changes; the examinations were accompanied by hyperspectral readings. During the early stage of the parasitism, significant differences between infected and non-infected sunflower plants were found in the reflectance of near and shortwave infrared areas. Physiological measurements revealed no differences between treatments until O. cumana inflorescences emerged. However, levels of several macro- and microelements tended to decrease during the early stage of O. cumana

  20. Impact of the limitations of state-of-the-art micro-fabrication processes on the performance of pillar array columns for liquid chromatography.

    Science.gov (United States)

    Op de Beeck, Jeff; De Malsche, Wim; Tezcan, Deniz S; De Moor, Piet; Desmet, Gert

    2012-05-25

    We report on the practical limitations of the current state-of-the-art in micro-fabrication technology to produce the small pillar sizes that are needed to obtain high efficiency pillar array columns. For this purpose, nine channels with a different pillar diameter, ranging from 5 to 0.5 μm were fabricated using state-of the-art deep-UV lithography and deep reactive ion etching (DRIE) etching technology. The obtained results strongly deviated from the theoretically expected trend, wherein the minimal plate height (H(min)) would reduce linearly with the pillar diameter. The minimal plate height decreases from 1.7 to 1.2 μm when going from 4.80 to 3.81 μm diameter pillars, but as the dimensions are further reduced, the minimal plate heights rise again to values around 2 μm. The smallest pillar diameter even produced the worst minimal plate height (4 μm). An in-depth scanning electron microscopy (SEM) inspection of the different channels clearly reveals that these findings can be attributed to the micro-fabrication limitations that are inevitably encountered when exploring the limits of deep-UV lithography and DRIE etching processes. When the target dimensions of the design approach the etching resolution limits, the band broadening increases in a strongly non-linear way with the decreased pillar dimensions. This highly non-linear relationship can be understood from first principles: when the machining error is of the order of 100-200 nm and when the target design size for the inter-pillar distance is of the order of 250 nm, this inevitably leads to pores that will range in size between 50 and 450 nm that we want to highlight with our paper highly non-linear relationship. This highly non-linear relationship can be understood from first principles: when the machining error is of the order of 100-200 nm and when the target design size for the inter-pillar distance is of the order of 250 nm, this inevitably leads to pores that will range in size between 50 and 450

  1. Preparation of Microcellular Epoxy Foams through a Limited-Foaming Process: A Contradiction with the Time-Temperature-Transformation Cure Diagram.

    Science.gov (United States)

    Wang, Lijun; Zhang, Chun; Gong, Wei; Ji, Yubi; Qin, Shuhao; He, Li

    2018-01-01

    3D cross-linking networks are generated through chemical reactions between thermosetting epoxy resin and hardener during curing. The curing degree of epoxy material can be increased by increasing curing temperature and/or time. The epoxy material must then be fully cured through a postcuring process to optimize its material characteristics. Here, a limited-foaming method is introduced for the preparation of microcellular epoxy foams (Lim-foams) with improved cell morphology, high thermal expansion coefficient, and good compressive properties. Lim-foams exhibit a lower glass transition temperature (T g ) and curing degree than epoxy foams fabricated through free-foaming process (Fre-foams). Surprisingly, however, the T g of Lim-foams is unaffected by postcuring temperature and time. This phenomenon, which is related to high gas pressure in the bubbles, contradicts that indicated by the time-temperature-transformation cure diagram. High bubble pressure promotes the movement of molecular chains under heating at low temperature and simultaneously suppresses the etherification cross-linking reaction during post-curing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Contrasting land uses in Mediterranean agro-silvo-pastoral systems generated patchy diversity patterns of vascular plants and below-ground microorganisms.

    Science.gov (United States)

    Bagella, Simonetta; Filigheddu, Rossella; Caria, Maria Carmela; Girlanda, Mariangela; Roggero, Pier Paolo

    2014-12-01

    The aims of this paper were (i) to define how contrasting land uses affected plant biodiversity in Mediterranean agro-silvo-pastoral-systems across a gradient of disturbance regimes: cork oak forests, secondary grasslands, hay crops, grass covered vineyards, tilled vineyards; (ii) to determine whether these patterns mirrored those of below-ground microorganisms and whether the components of γ-diversity followed a similar model. The disturbance regimes affected plant assemblage composition. Species richness decreased with increasing land use intensity, the Shannon index showed the highest values in grasslands and hay crops. Plant assemblage composition patterns mirrored those of Basidiomycota and Ascomycota. Richness in Basidiomycota, denitrifying bacteria and microbial biomass showed the same trend as that observed for vascular plant richness. The Shannon index pattern of below-ground microorganisms was different from that of plants. The plant γ-diversity component model weakly mirrored those of Ascomycota. Patchy diversity patterns suggest that the maintenance of contrasting land uses associated with different productions typical of agro-silvo-pastoral-systems can guarantee the conservation of biodiversity. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  3. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites.

    Science.gov (United States)

    Aratchige, N S; Lesna, I; Sabelis, M W

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract predatory mites (Neoseiulus cucumeris). Since our aim was to demonstrate such odours and not their relevance under soil conditions, the experiments were carried out using a classic Y-tube olfactometer in which the predators moved on a Y-shaped wire in open air. We found that food-deprived female predators can discriminate between odours from infested bulbs and odours from uninfested bulbs or artificially wounded bulbs. No significant difference in attractiveness to predators was found between clean bulbs and bulbs either wounded 30 min or 3 h before the experiment. These results indicate that it may not be simply the wounding of the bulbs, but rather the feeding by rust mites, which causes the bulb to release odours that attract N. cucumeris. Since bulbs are belowground plant structures, the olfactometer results demonstrate the potential for odour-mediated interactions in the soil. However, their importance in the actual soil medium remains to be demonstrated.

  4. Robust test limits

    NARCIS (Netherlands)

    Albers, Willem/Wim; Kallenberg, W.C.M.; Otten, G.D.

    1997-01-01

    Because of inaccuracies of the measurement process inspection of manufactured parts requires test limits which are more strict than the given specification limits. Test limits derived under the assumption of normality for product characteristics turn out to violate the prescribed bound on the

  5. Belowground ecosystems [chapter 9

    Science.gov (United States)

    Carole Coe Klopatek

    1995-01-01

    The USDA Forest Service defined ecosystem management as "an ecological approach to achieve multiple-use management of national forests and grasslands by blending the needs of people and environmental values in such a way that national forests and grasslands represent diverse, healthy, productive, and sustainable ecosystems" (June 4, 1992, letter from Chief FS...

  6. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  7. Determination of a limit on the branching ratio of the rare process b → s γ with the L3 detector at LEP

    International Nuclear Information System (INIS)

    Dorne, I.

    1996-01-01

    This work is dedicated to the determination of a limit on the branching ratio of the rare process b -> Sγ, from Z -> bb-bar events collected at LEP with the L3 detector during collisions at √S ∼ M Z , M Z ± 2 GeV. The rare decay of the b quark, b -> sγ, is forbidden at tree level and occurs, in the Standard Model, through one loop diagram (called penguin diagram) which makes it sensitive to contributions of new particles such as charged Higgs bosons or supersymmetric particles. The theoretical branching ratio is given in Standard Model by Br(b->Sγ) (2.55 ± 0.58) x 10 -4 . The aim of this study was to observe, in the inclusive mode, a possible excess of the rate of the b -> sγ transition, compare to the expected value. The selection of b hadrons from Z hadronic decays is achieved by the use of both an algorithm based on a multidimensional analysis of the event shape and an algorithm based on the impact parameter of the tracks. The energetic photon is selected by using a π 0 /γ discriminator based on the transverse shape of its electromagnetic shower. The s-jet reconstruction is achieved by the use of an iterative method with search of the minimum invariant mass. It allows the determination of the b hadron rest frame, which picks near 2.5 GeV, is used in a new method of signal events simulation. No excess of event is observed in the data after the analysis of 1.5 million of Z decays. The limit obtained, when the systematic errors are included, is: Br(b -> sγ) ≤9.2 x 10 4 at 90% confidence level. This result is consistent with the Standard Model expectation. (author)

  8. Magnitude of Alloresponses to MHC Class I/II Expressing Human Cardiac Myocytes is Limited by their Intrinsic Ability to Process and Present Antigenic Peptides

    Directory of Open Access Journals (Sweden)

    Aftab A. Ansari

    2003-01-01

    Full Text Available In this investigation we have explored the relationship between the weak allogenicity of cardiac myocytes and their capacity to present allo-antigens by examining the ability of a human cardiac myocyte cell line (W-1 to process and present nominal antigens. W-1 cells (HLA-A*0201 and HLA-DR β1*0301 pulsed with the influenza A matrix 1 (58-66 peptide (M1 were able to serve as targets for the HLA-A*0201 restricted CTL line PG, specific for M1-peptide. However, PG-CTLs were unable to lyse W-1 target cells infected with a recombinant vaccinia virus expressing the M1 protein (M1-VAC. Pretreatment of these M1-VAC targets with IFN-γ partially restored their ability to process and present the M1 peptide. However, parallel studies demonstrated that IFN-γ pretreated W-1's could not process tetanus toxin (TT or present the TT(830-843 peptide to HLA-DR3 restricted TT-primed T cells. Semi-quantitative RT-PCR measurements revealed significantly lower constitutive levels of expression for MHC class I, TAP-1/2, and LMP-2/7 genes in W-1s that could be elevated by pretreatment with IFN-γ to values equal to or greater than those expressed in EBV-PBLs. However, mRNA levels for the genes encoding MHC class II, Ii, CIITA, and DMA/B were markedly lower in both untreated and IFN-γ pretreated W-1s relative to EBV-PBLs. Furthermore, pulse-chase analysis of the corresponding genes revealed significantly lower protein levels and longer half-life expression in W-1s relative to EBV-PBLs. These results suggest that weak allogenicity of cardiac myocytes may be governed by their limited expression of MHC genes and gene products critical for antigen processing and presentation.

  9. Quench limits

    International Nuclear Information System (INIS)

    Sapinski, M.

    2012-01-01

    With thirteen beam induced quenches and numerous Machine Development tests, the current knowledge of LHC magnets quench limits still contains a lot of unknowns. Various approaches to determine the quench limits are reviewed and results of the tests are presented. Attempt to reconstruct a coherent picture emerging from these results is taken. The available methods of computation of the quench levels are presented together with dedicated particle shower simulations which are necessary to understand the tests. The future experiments, needed to reach better understanding of quench limits as well as limits for the machine operation are investigated. The possible strategies to set BLM (Beam Loss Monitor) thresholds are discussed. (author)

  10. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  11. Louisiana SIP: LAC 33:III Ch 21 Subchap J, 2147--Limiting Volatile Organic Compound (VOC) Emissions from Reactor Processes and Distillation Operations in Synthetic Organic Chemical manufacturing Industry (SOCMI); SIP effective 1998-02-02 (LAc74) to more..

    Science.gov (United States)

    Louisiana SIP: LAC 33:III Ch 21 Subchap J, 2147--Limiting Volatile Organic Compound (VOC) Emissions from Reactor Processes and Distillation Operations in Synthetic Organic Chemical manufacturing Industry (SOCMI); SIP effective 1998-02-02 (LAc74) more...

  12. Louisiana SIP: LAC 33:III Ch 2147. Limiting Volatile Organic Compound (VOC) Emissions from Reactor Processes and Distillation Operations in Synthetic Organic Chemical manufacturing Industry (SOCMI); SIP effective 2011-08-04 (LAd34) to 2017-09-27

    Science.gov (United States)

    Louisiana SIP: LAC 33:III Ch 2147. Limiting Volatile Organic Compound (VOC) Emissions from Reactor Processes and Distillation Operations in Synthetic Organic Chemical manufacturing Industry (SOCMI); SIP effective 2011-08-04 (LAd34) to 2017-09-27

  13. Reductions of plant cover induced by sheep grazing change the above-belowground partition and chemistry of organic C stocks in arid rangelands of Patagonian Monte, Argentina.

    Science.gov (United States)

    Larreguy, C; Carrera, A L; Bertiller, M B

    2017-09-01

    The objective of this study was to estimate the size and chemical quality of the total organic C stock and its partition between above-belowground plant parts and soil at sites with different plant cover induced by sheep grazing in the arid Patagonian Monte. This study was conducted at six representative sites with increasing signs of canopy disturbance attributed to grazing pressure. We used faeces density as a proxy of grazing pressure at each site. We assessed the total plant cover, shrub and perennial grass cover, total standing aboveground biomass (AGB), litter mass and belowground biomass (BGB) at each site. We further estimated the content of organic C, lignin and soluble phenols in plant compartments and the content of organic C, organic C in humic substances (recalcitrant C) and water soluble C (labile C) in soil at each site. Total plant cover was significantly related to grazing pressure. Standing AGB and litter mass decreased with increasing canopy disturbance while BGB did not vary across sites. Total organic C stock and the organic C stock in standing AGB increased with increasing total plant, shrub, and perennial grass cover. The organic C stock in litter mass increased with increasing total plant and shrub cover, while the organic C stock in BGB did not vary across sites. Lignin content in plant compartments increased with increasing total and shrub cover, while soluble phenols content did not change across sites. The organic C stock and the water soluble C content in soil were positively associated with perennial grass cover. Changes in total plant cover induced by grazing pressure negatively affected the size of the total organic C stock, having minor impact on the size of belowground than aboveground components. The reduction of perennial grass cover was reflected in decreasing chemical quality of the organic C stock in soil. Accordingly, plant managerial strategies should not only be focused on the amount of organic C sequestered but also on the

  14. Evidence that acidification-induced declines in plant diversity and productivity are mediated by changes in below-ground communities and soil properties in a semi-arid steppe

    Science.gov (United States)

    Chen, Dima; Lan, Zhichun; Bai, Xue; Grace, James B.; Bai, Yongfei

    2013-01-01

    Anthropogenic acid deposition–induced soil acidification is one of the major threats to biodiversity, ecosystem functioning and services. Few studies, however, have explored in detail how above-ground changes in plant species richness and productivity resulting from soil acidification are mediated by effects on below-ground biota and soil properties.

  15. Cowpea N rhizodeposition and its below-ground transfer to a co-existing and to a subsequent millet crop on a sandy soil of the Sudano-Sahelian eco-zone

    DEFF Research Database (Denmark)

    Laberge, Guillaume; Haussmann, Bettina I.G.; Ambus, Per

    2011-01-01

    Nitrogen (N) rhizodeposition by cowpea (Vigna unguiculata (L.) Walp) is potentially a large N source in cropping systems of Sub-Saharan Africa. A field experiment was conducted to measure cowpea N rhizodeposition under the conditions of the Sudano-Sahelian zone using direct 15N labelling techniques...... to trace the amount of deposition and its transfer to associated and subsequent crops. Half of the total cowpea crop N was located below-ground at plant maturity, which exceeded 20 kg N ha−1 when intercropped with millet. Only 15% of the below-ground cowpea N was recovered in roots, while 85% was found...... in the rhizodeposited pools. The experiment demonstrated that direct below-ground N transfer occurred from cowpea to millet in intercrop at a rate of 2 kg N ha−1 over the growing season. Forty percent of the 25 kg below-ground N that the cowpea crop left at harvest were identifiable in the top 0.30 m soil...

  16. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  17. Calculation of the detection limits for radionuclides identified in gamma-ray spectra based on post-processing peak analysis results.

    Science.gov (United States)

    Korun, M; Vodenik, B; Zorko, B

    2018-03-01

    A new method for calculating the detection limits of gamma-ray spectrometry measurements is presented. The method is applicable for gamma-ray emitters, irrespective of the influences of the peaked background, the origin of the background and the overlap with other peaks. It offers the opportunity for multi-gamma-ray emitters to calculate the common detection limit, corresponding to more peaks. The detection limit is calculated by approximating the dependence of the uncertainty in the indication on its value with a second-order polynomial. In this approach the relation between the input quantities and the detection limit are described by an explicit expression and can be easy investigated. The detection limit is calculated from the data usually provided by the reports of peak-analyzing programs: the peak areas and their uncertainties. As a result, the need to use individual channel contents for calculating the detection limit is bypassed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The Limited Role of Number of Nested Syntactic Dependencies in Accounting for Processing Cost: Evidence from German Simplex and Complex Verbal Clusters

    Directory of Open Access Journals (Sweden)

    Markus Bader

    2018-01-01

    Full Text Available This paper presents three acceptability experiments investigating German verb-final clauses in order to explore possible sources of sentence complexity during human parsing. The point of departure was De Vries et al.'s (2011 generalization that sentences with three or more crossed or nested dependencies are too complex for being processed by the human parsing mechanism without difficulties. This generalization is partially based on findings from Bach et al. (1986 concerning the acceptability of complex verb clusters in German and Dutch. The first experiment tests this generalization by comparing two sentence types: (i sentences with three nested dependencies within a single clause that contains three verbs in a complex verb cluster; (ii sentences with four nested dependencies distributed across two embedded clauses, one center-embedded within the other, each containing a two-verb cluster. The results show that sentences with four nested dependencies are judged as acceptable as control sentences with only two nested dependencies, whereas sentences with three nested dependencies are judged as only marginally acceptable. This argues against De Vries et al.'s (2011 claim that the human parser can process no more than two nested dependencies. The results are used to refine the Verb-Cluster Complexity Hypothesis of Bader and Schmid (2009a. The second and the third experiment investigate sentences with four nested dependencies in more detail in order to explore alternative sources of sentence complexity: the number of predicted heads to be held in working memory (storage cost in terms of the Dependency Locality Theory [DLT], Gibson, 2000 and the length of the involved dependencies (integration cost in terms of the DLT. Experiment 2 investigates sentences for which storage cost and integration cost make conflicting predictions. The results show that storage cost outweighs integration cost. Experiment 3 shows that increasing integration cost in sentences

  19. Recommendations to the NRC for review criteria for alternative methods of low-level radioactive waste disposal: Task 2a, Below-ground vaults

    International Nuclear Information System (INIS)

    Denson, R.H.; Bennett, R.D.; Wamsley, R.M.; Bean, D.L.; Ainsworth, D.L.

    1987-12-01

    The US Army Engineer Waterways Experiment Station (WES) and the US Army Engineer Division, Huntsville (HNDED) have developed general design criteria and specific design review criteria for the below-ground vault (BGV) alternative method of low-level radioactive waste (LLW) disposal. A BGV is a reinforced concrete vault (floor, walls, and roof) placed underground below the frost line, and above the water table, surrounded by filter blanket and drainage zones and covered with a low permeability earth layer and top soil with vegetation. Eight major review criteria categories have been developed ranging from the loads imposed on the BGV structure through material quality and durability considerations. Specific design review criteria have been developed in detail for seven of the eight major categories. 59 refs., 14 figs., 2 tabs

  20. Belowground Plant–Herbivore Interactions Vary among Climate-Driven Range-Expanding Plant Species with Different Degrees of Novel Chemistry

    Directory of Open Access Journals (Sweden)

    Rutger A. Wilschut

    2017-10-01

    Full Text Available An increasing number of studies report plant range expansions to higher latitudes and altitudes in response to global warming. However, consequences for interactions with other species in the novel ranges are poorly understood. Here, we examine how range-expanding plant species interact with root-feeding nematodes from the new range. Root-feeding nematodes are ubiquitous belowground herbivores that may impact the structure and composition of natural vegetation. Because of their ecological novelty, we hypothesized that range-expanding plant species will be less suitable hosts for root-feeding nematodes than native congeneric plant species. In greenhouse and lab trials we compared nematode preference and performance of two root-feeding nematode species between range-expanding plant species and their congeneric natives. In order to understand differences in nematode preferences, we compared root volatile profiles of all range-expanders and congeneric natives. Nematode preferences and performances differed substantially among the pairs of range-expanders and natives. The range-expander that had the most unique volatile profile compared to its related native was unattractive and a poor host for nematodes. Other range-expanding plant species that differed less in root chemistry from native congeners, also differed less in nematode attraction and performance. We conclude that the three climate-driven range-expanding plant species studied varied considerably in their chemical novelty compared to their congeneric natives, and therefore affected native root-feeding nematodes in species-specific ways. Our data suggest that through variation in chemical novelty, range-expanding plant species may vary in their impacts on belowground herbivores in the new range.

  1. Limit analysis via creep

    International Nuclear Information System (INIS)

    Taroco, E.; Feijoo, R.A.

    1981-07-01

    In this paper it is presented a variational method for the limit analysis of an ideal plastic solid. This method has been denominated as Modified Secundary Creep and enables to find the collapse loads through a minimization of a functional and a limit process. Given an ideal plastic material it is shown how to determinate the associated secundary creep constitutive equation. Finally, as an application, it is found the limit load in an pressurized von Mises rigid plastic sphere. (Author) [pt

  2. New limits on 2β processes in 40Ca and 46Ca by using low radioactive CaF2(Eu) crystal scintillators

    International Nuclear Information System (INIS)

    Belli, P.; Bernabei, R.; Dai, C.J.

    2001-01-01

    The development of highly radiopure CaF 2 (Eu) crystal scintillators has been performed aiming at a substantial sensitivity enhancement of the 2β decay investigation and of the search for dark matter particles with spin-dependent (SD) interaction. The results of CaF 2 (Eu) background measurements and simulation are presented. New and highly improved T 1/2 limits on the 2β decay of 46 Ca and the double electron capture of 40 Ca are obtained

  3. Limit lines for risk

    International Nuclear Information System (INIS)

    Cox, D.C.; Baybutt, P.

    1982-01-01

    Approaches to the regulation of risk from technological systems, such as nuclear power plants or chemical process plants, in which potential accidents may result in a broad range of adverse consequences must take into account several different aspects of risk. These include overall or average risk, accidents posing high relative risks, the rate at which accident probability decreases with increasing accident consequences, and the impact of high frequency, low consequence accidents. A hypothetical complementary cumulative distribution function (CCDF), with appropriately chosen parametric form, meets all these requirements. The Farmer limit line, by contrast, places limits on the risks due to individual accident sequences, and cannot adequately account for overall risk. This reduces its usefulness as a regulatory tool. In practice, the CCDF is used in the Canadian nuclear licensing process, while the Farmer limit line approach, supplemented by separate qualitative limits on overall risk, is employed in the United Kingdom

  4. Algorithm оf Computer Model Realization оf High-Frequency Processes in Switchgears Containing Non-Linear Over-Voltage Limiters

    Directory of Open Access Journals (Sweden)

    Ye. V. Dmitriev

    2007-01-01

    Full Text Available Analysis of the Over-Voltage Limiter (OVL influence on electromagnetic high-frequency over-voltages at commutations with isolators of unloaded sections of wires and possibility of application of a frequency-dependent resistor in case of necessity to facilitate OVL operation conditions is provided in the paper.It is shown that it is necessary to take into account characteristics of OVL by IEEE circuit and its modifications at computer modeling of high-frequency over-voltages.

  5. Computer Security: Governmentwide Planning Process Had Limited Impact. Report to the Chairman, Committee on Science, Space, and Technology, House of Representatives.

    Science.gov (United States)

    General Accounting Office, Washington, DC. Information Management and Technology Div.

    As required by the Computer Security Act of 1987, federal agencies have to identify systems that contain sensitive information and develop plans to safeguard them. The planning process was assessed in 10 civilian agencies as well as the extent to which they had implemented planning controls described in 22 selected plans. The National Institute of…

  6. Clean solutions to the incoming wafer quality impact on lithography process yield limits in a dynamic copper/low-k research and development environment

    Science.gov (United States)

    Lysaght, Patrick S.; Ybarra, Israel; Sax, Harry; Gupta, Gaurav; West, Michael; Doros, Theodore G.; Beach, James V.; Mello, Jim

    2000-06-01

    The continued growth of the semiconductor manufacturing industry has been due, in large part, to improved lithographic resolution and overlay across increasingly larger chip areas. Optical lithography continues to be the mainstream technology for the industry with extensions of optical lithography being employed to support 180 nm product and process development. While the industry momentum is behind optical extensions to 130 nm, the key challenge will be maintaining an adequate and affordable process latitude (depth of focus/exposure window) necessary for 10% post-etch critical dimension (CD) control. If the full potential of optical lithography is to be exploited, the current lithographic systems can not be compromised by incoming wafer quality. Impurity specifications of novel Low-k dielectric materials, plating solutions, chemical-mechanical planarization (CMP) slurries, and chemical vapor deposition (CVD) precursors are not well understood and more stringent control measures will be required to meet defect density targets as identified in the National Technology Roadmap for Semiconductors (NTRS). This paper identifies several specific poor quality wafer issues that have been effectively addressed as a result of the introduction of a set of flexible and reliable wafer back surface clean processes developed on the SEZ Spin-Processor 203 configured for processing of 200 mm diameter wafers. Patterned wafers have been back surface etched by means of a novel spin process contamination elimination (SpCE) technique with the wafer suspended by a dynamic nitrogen (N2) flow, device side down, via the Bernoulli effect. Figure 1 illustrates the wafer-chuck orientation within the process chamber during back side etch processing. This paper addresses a number of direct and immediate benefits to the MicraScan IIITM deep-ultraviolet (DUV) step-and-scan system at SEMATECH. These enhancements have resulted from the resolution of three significant problems: (1) back surface

  7. Assessing the Significance of Above- and Belowground Carbon Allocation of Fast- and Slow-Growing Families of Loblolly Pine - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Topa, M. A.; Weinstein, D. A.; Retzlaff, W. A.

    2001-03-01

    During this project we experimentally evaluated the below-ground biomass and carbon allocation and partitioning of four different fast- and slow-growing families of loblolly pine located in Scotland County, NC, in an effort to increase the long-term performance of the crop. The trees were subjected to optimal nutrition and control since planting in 1993. Destructive harvests in 1998 and 2000 were used for whole?plant biomass estimates and to identify possible family differences in carbon acquisition (photosynthesis) and water use efficiency. At regular intervals throughout each year we sampled tissues for carbohydrate analyses to assess differences in whole-tree carbon storage. Mini rhizotron observation tubes were installed to monitor root system production and turnover. Stable isotope analysis was used to examine possible functional differences in water and nutrient acquisition of root systems between the various families. A genetic dissection of root ontogenic and architectural traits, including biomass partitioning, was conducted using molecular markers to better understand the functional implications of these traits on resource acquisition and whole-plant carbon allocation.

  8. In vivo photosystem I reduction in thermophilic and mesophilic cyanobacteria: The thermal resistance of the process is limited by factors other than the unfolding of the partners

    International Nuclear Information System (INIS)

    Duran, Raul V.; Hervas, Manuel; Rosa, Miguel A. de la; Navarro, Jose A.

    2005-01-01

    Photosystem I reduction by plastocyanin and cytochrome c 6 in cyanobacteria has been extensively studied in vitro, but much less information is provided on this process inside the cell. Here, we report an analysis of the electron transfer from both plastocyanin and cytochrome c 6 to photosystem I in intact cells of several cyanobacterial species, including a comparative study of the temperature effect in mesophilic and thermophilic organisms. Our data show that cytochrome c 6 reduces photosystem I by following a reaction mechanism involving complex formation, whereas the copper-protein follows a simpler collisional mechanism. These results contrast with previous kinetic studies in vitro. The effect of temperature on photosystem I reduction leads us to conclude that the thermal resistance of this process is determined by factors other than the proper stability of the protein partners

  9. A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes

    Science.gov (United States)

    Fridlin, Ann; vanDiedenhoven, Bastiaan; Ackerman, Andrew S.; Avramov, Alexander; Mrowiec, Agnieszka; Morrison, Hugh; Zuidema, Paquita; Shupe, Matthew D.

    2012-01-01

    Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration N(sub IN) measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration N(sub i) is then limited to a small fraction of overlying N(sub IN) that is determined by the cloud-top entrainment rate w(sub e) divided by the number-weighted ice fall speed at the surface v(sub f). Because w(sub c) 10 cm/s, N(sub i)/N(sub IN)<< 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing N(sub IN) (when w(sub e)/v(sub f)< 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud N(sub IN) must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed.

  10. Post-fire erosion control mulches alter belowground processes and nitrate reductase activity of a perennial forb, heartleaf arnica (Arnica cordifolia)

    Science.gov (United States)

    Erin M. Berryman; Penelope Morgan; Peter R. Robichaud; Deborah Page-Dumroese

    2014-01-01

    Four years post-wildfire, we measured soil and plant properties on hillslopes treated with two different mulches (agricultural wheat straw and wood strands) and a control (unmulched, but burned). Soil total N was about 40% higher and microbial respiration of a standard wood substrate was nearly twice as high in the mulched plots compared to the unmulched plots. Greater...

  11. Application for approval of derived authorized limits for the release of the 190-C trenches and 105-C process water tunnels at the Hanford Site: Volume 2 - source term development

    International Nuclear Information System (INIS)

    Denham, D.H.; Winslow, S.L.; Moeller, M.P.; Kennedy, W.E. Jr.

    1997-03-01

    As part of environmental restoration activities at the Hanford Site, Bechtel Hanford, Inc. is conducting a series of evaluations to determine appropriate release conditions for specific facilities following the completion of decontamination and decommissioning projects. The release conditions, with respect to the residual volumetric radioactive contamination, are termed authorized limits. This report presents the summary of the supporting information and the final application for approval of derived authorized limits for the release of the 190-C trenches and the 105-C process water tunnels. This document contains two volumes; this volume (Vol. 2) contains the radiological characterization data, spreadsheet analyses, and radiological source terms

  12. The processing of positional information in a two-item sequence limits the emergence of symmetry in baboons (Papio papio), but not in humans (Homo sapiens).

    Science.gov (United States)

    Fagot, Joël; Malassis, Raphaelle; Medam, Tiphaine

    2018-03-01

    When trained to associate Stimulus A to Stimulus B, humans can derive the untrained symmetrical B to A relation while nonhuman animals have much more difficulties. Urcuioli (2008, Journal of the Experimental Analysis of Behavior, 90, 257--282; 2015, Conductal, 3, 4--25) proposed that the apparent difficulty of animals in symmetry testing reflects their double encoding of the information on the stimuli (identity and relation) and their positional (i.e., spatial and temporal/ordinal) characteristics. This comparative study tested the emergence of symmetry in humans and baboons in a task in which the position of the stimuli was manipulated independently of their relation. Humans and baboons initially learned to associate pairs of visual shapes on a touch screen in a specific order. Three pairs of (A-B, C-D, and E-F) stimuli were used in training. After training, the two species were tested with the B-A, F-C, and E-D pairs. The B-A pairs preserved the association initially learned with A-B but reversed the positional information relative to training. The F-C pair neither preserved the association nor the positional information of the training pairs, and positional information were the only cues preserved in the E-D pair. Humans showed a response time advantage for B-A, suggesting symmetry, but also for E-D, suggesting that they also process positional information. In baboons, the advantage was found only for E-D, suggesting that they only process positional information. These results confirm that the processing of stimulus pairs differ between nonhuman animals to humans.

  13. High Power Efficiency Solution-Processed Blue Phosphorescent Organic Light-Emitting Diodes Using Exciplex-Type Host with a Turn-on Voltage Approaching the Theoretical Limit.

    Science.gov (United States)

    Ban, Xinxin; Sun, Kaiyong; Sun, Yueming; Huang, Bin; Ye, Shanghui; Yang, Min; Jiang, Wei

    2015-11-18

    Three solution-processable exciplex-type host materials were successfully designed and characterized by equal molar blending hole transporting molecules with a newly synthesized electron transporting material, which possesses high thermal stability and good film-forming ability through a spin-coating technique. The excited-state dynamics and the structure-property relationships were systematically investigated. By gradually deepening the highest occupied molecular orbital (HOMO) level of electron-donating components, the triplet energy of exciplex hosts were increased from 2.64 to 3.10 eV. Low temperature phosphorescence spectra demonstrated that the excessively high triplet energy of exciplex would induce a serious energy leakage from the complex state to the constituting molecule. Furthermore, the low energy electromer state, which only exists under the electroexcitation, was found as another possible channel for energy loss in exciplex-based phosphorescent organic light-emitting diodes (OLEDs). In particular, as quenching of the exciplex-state and the triplet exciton were largely eliminated, solution-processed blue phosphorescence OLEDs using the exciplex-type host achieved an extremely low turn-on voltage of 2.7 eV and record-high power efficiency of 22.5 lm W(-1), which were among the highest values in the devices with identical structure.

  14. Evaluation of the performance and limitations of empirical partition-relations and process based multisurface models to predict trace element solubility in soils

    Energy Technology Data Exchange (ETDEWEB)

    Groenenberg, J.E.; Bonten, L.T.C. [Alterra, Wageningen UR, P.O. Box 47, 6700 AA Wageningen (Netherlands); Dijkstra, J.J. [Energy research Centre of the Netherlands ECN, P.O. Box 1, 1755 ZG Petten (Netherlands); De Vries, W. [Department of Environmental Systems Analysis, Wageningen University, Wageningen UR, P.O. Box 47, 6700 AA Wageningen (Netherlands); Comans, R.N.J. [Department of Soil Quality, Wageningen University, Wageningen UR, P.O. Box 47, 6700 AA Wageningen (Netherlands)

    2012-07-15

    Here we evaluate the performance and limitations of two frequently used model-types to predict trace element solubility in soils: regression based 'partition-relations' and thermodynamically based 'multisurface models', for a large set of elements. For this purpose partition-relations were derived for As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, Se, V, Zn. The multi-surface model included aqueous speciation, mineral equilibria, sorption to organic matter, Fe/Al-(hydr)oxides and clay. Both approaches were evaluated by their application to independent data for a wide variety of conditions. We conclude that Freundlich-based partition-relations are robust predictors for most cations and can be used for independent soils, but within the environmental conditions of the data used for their derivation. The multisurface model is shown to be able to successfully predict solution concentrations over a wide range of conditions. Predicted trends for oxy-anions agree well for both approaches but with larger (random) deviations than for cations.

  15. Footprint area analysis of binary imaged Cupriavidus necator cells to study PHB production at balanced, transient, and limited growth conditions in a cascade process.

    Science.gov (United States)

    Vadlja, Denis; Koller, Martin; Novak, Mario; Braunegg, Gerhart; Horvat, Predrag

    2016-12-01

    Statistical distribution of cell and poly[3-(R)-hydroxybutyrate] (PHB) granule size and number of granules per cell are investigated for PHB production in a five-stage cascade (5CSTR). Electron microscopic pictures of cells from individual cascade stages (R1-R5) were converted to binary pictures to visualize footprint areas for polyhydroxyalkanoate (PHA) and non-PHA biomass. Results for each stage were correlated to the corresponding experimentally determined kinetics (specific growth rate μ and specific productivity π). Log-normal distribution describes PHA granule size dissimilarity, whereas for R1 and R4, gamma distribution best reflects the situation. R1, devoted to balanced biomass synthesis, predominately contains cells with rather small granules, whereas with increasing residence time τ, maximum and average granule sizes by trend increase, approaching an upper limit determined by the cell's geometry. Generally, an increase of intracellular PHA content and ratio of granule to cell area slow down along the cascade. Further, the number of granules per cell decreases with increasing τ. Data for μ and π obtained by binary picture analysis correlate well with the experimental results. The work describes long-term continuous PHA production under balanced, transient, and nutrient-deficient conditions, as well as their reflection on the granules size, granule number, and cell structure on the microscopic level.

  16. Seasonal Belowground Ecosystem and Eco-enzymatic Responses to Soil pH and Phosphorus Availability in Temperate Hardwood Forests

    Science.gov (United States)

    Smemo, K. A.; Deforest, J. L.; Petersen, S. L.; Burke, D.; Hewins, C.; Kluber, L. A.; Kyker, S. R.

    2013-12-01

    Atmospheric acid deposition can increase phosphorus (P) limitation in temperate hardwood forests by increasing N availability, and therefore P demand, and/or by decreasing pH and occluding inorganic P. However, only recently have studies demonstrated that P limitation can occur in temperate forests and very little is known about the temporal aspects of P dynamics in acidic forest soils and how seasonal shifts in nutrient availability and demand influence microbial investment in extracellular enzymes. The objectives of this study were to investigate how P availability and soil pH influence seasonal patterns of nutrient cycling and soil microbial activity in hardwood forests that experience chronic acid deposition. We experimentally manipulated soil pH, P, or both for three years and examined soil treatment responses in fall, winter, spring, early summer, and late summer. We found that site (glaciated versus unglaciated) and treatment had the most significant influence on nutrient pools and cycling. In general, nutrient pools were higher in glaciated soils than unglaciated for measured nutrients, including total C and N (2-3 times higher), extractable inorganic nitrogen, and readily available P. Treatment had no impact on total C and N pools in either region, but did affect other measured nutrients such as ammonium, which was greatest in the elevated pH treatment for both sites. As expected, readily available P pools were highest in the elevated P treatments (3 fold increase in both sites), but raising pH decreased available P pools in the glaciated site. Raising soil pH increased both net N mineralization rates and net P mineralization rates, regardless of site. Nitrification responses were complex, but we observed an overall significant nitrification increase under elevated pH, particularly in the growing season. Extracellular enzyme activity showed more seasonal patterns than site and treatment effects, exhibiting significant growing season activity reductions for

  17. Thermal background noise limitations

    Science.gov (United States)

    Gulkis, S.

    1982-01-01

    Modern detection systems are increasingly limited in sensitivity by the background thermal photons which enter the receiving system. Expressions for the fluctuations of detected thermal radiation are derived. Incoherent and heterodyne detection processes are considered. References to the subject of photon detection statistics are given.

  18. Assessing process of paediatric care in a resource-limited setting: a cross-sectional audit of district hospitals in Rwanda.

    Science.gov (United States)

    Hategeka, Celestin; Shoveller, Jeannie; Tuyisenge, Lisine; Lynd, Larry D

    2018-05-01

    Routine assessment of quality of care helps identify deficiencies which need to be improved. While gaps in the emergency care of children have been documented across sub-Saharan Africa, data from Rwanda are lacking. To assess the care of sick infants and children admitted to Rwandan district hospitals and the extent to which it follows currently recommended clinical practice guidelines in Rwanda. Data were gathered during a retrospective cross-sectional audit of eight district hospitals across Rwanda in 2012/2013. Medical records were randomly selected from each hospital and were reviewed to assess the process of care, focusing on the leading causes of under-5 mortality, including neonatal conditions, pneumonia, malaria and dehydration/diarrhoea. Altogether, 522 medical records were reviewed. Overall completion of a structured neonatal admission record was above 85% (range 78.6-90.0%) and its use was associated with better documentation of key neonatal signs (median score 6/8 and 2/8 when used and not used, respectively). Deficiencies in the processes of care were identified across hospitals and there were rural/urban disparities for some indicators. For example, neonates admitted to urban district hospitals were more likely to receive treatment consistent with currently recommended guidelines [e.g. gentamicin (OR 2.52, 95% CI 1.03-6.43) and fluids (OR 2.69, 95% CI 1.2-6.2)] than those in rural hospitals. Likewise, children with pneumonia admitted to urban hospitals were more likely to receive the correct dosage of gentamicin (OR 4.47, 95% CI 1.21-25.1) and to have their treatment monitored (OR 3.75, 95% CI 1.57-8.3) than in rural hospitals. Furthermore, children diagnosed with malaria and admitted to urban hospitals were more likely to have their treatment (OR 2.7, 95% CI 1.15-6.41) monitored than those in rural hospitals. Substantial gaps were identified in the process of neonatal and paediatric care across district hospitals in Rwanda. There is a need to (i

  19. A Standardized Needs Assessment Tool to Inform the Curriculum Development Process for Pediatric Resuscitation Simulation-Based Education in Resource-Limited Settings

    Directory of Open Access Journals (Sweden)

    Nicole Shilkofski

    2018-02-01

    Full Text Available IntroductionUnder five mortality rates (UFMR remain high for children in low- and middle-income countries (LMICs in the developing world. Education for practitioners in these environments is a key factor to improve outcomes that will address United Nations Sustainable Development Goals 3 and 10 (good health and well being and reduced inequalities. In order to appropriately contextualize a curriculum using simulation, it is necessary to first conduct a needs assessment of the target learner population. The World Health Organization (WHO has published a tool to assess capacity for emergency and surgical care in LMICs that is adaptable to this goal.Materials and methodsThe WHO Tool for Situational Analysis to Assess Emergency and Essential Surgical Care was modified to assess pediatric resuscitation capacity in clinical settings in two LMICs: Uganda and Myanmar. Modifications included assessment of self-identified learning needs, current practices, and perceived epidemiology of disease burden in each clinical setting, in addition to assessment of pediatric resuscitation capacity in regard to infrastructure, procedures, equipment, and supplies. The modified tool was administered to 94 respondents from the two settings who were target learners of a proposed simulation-based curriculum in pediatric and neonatal resuscitation.ResultsInfectious diseases (respiratory illnesses and diarrheal disease were cited as the most common causes of pediatric deaths in both countries. Self-identified learning needs included knowledge and skill development in pediatric airway/breathing topics, as well as general resuscitation topics such as CPR and fluid resuscitation in shock. Equipment and supply availability varied substantially between settings, and critical shortages were identified in each setting. Current practices and procedures were often limited by equipment availability or infrastructural considerations.Discussion and conclusionEpidemiology of disease

  20. Efficiency-limiting processes in cyclopentadithiophene-bridged donor-acceptor-type dyes for solid-state dye-sensitized solar cells

    KAUST Repository

    Hinkel, Felix

    2018-01-26

    The charge generation and recombination processes in three novel push-pull photosensitizers for dye-sensitized solar cells (DSSCs) are studied by ps–μs transient absorption (TA) and quasi-steady-state photoinduced absorption (PIA) spectroscopy. The three cyclopentadithiophene-based photosensitizer dye molecules exhibit comparably low power conversion efficiencies ranging from 0.8% to 1.7% in solid-state DSSCs. We find that the photocurrents increase in the presence of Li-salt additives. Both TA and PIA measurements observe long-lived dye cations created by electron injection from the dyes’ excited state for two dyes from the series. However, the third dye shows significantly lower performance as a consequence of the less efficient electron injection even after the addition of Li-salts and faster electron-hole recombination on the ns-μs time scale. In essence, the prerequisites for this class of donor-π bridge-acceptor photosensitizers to reach higher charge generation efficiencies are a combination of strong dipole moments and fine tuning of the electronic landscape at the titania-dye interface by Li-salt addition.

  1. Efficiency-limiting processes in cyclopentadithiophene-bridged donor-acceptor-type dyes for solid-state dye-sensitized solar cells

    KAUST Repository

    Hinkel, Felix; Kim, Yoojin M.; Zagraniarsky, Yulian; Schlü tter, Florian; Andrienko, Denis; Mü llen, Klaus; Laquai, Fré dé ric

    2018-01-01

    The charge generation and recombination processes in three novel push-pull photosensitizers for dye-sensitized solar cells (DSSCs) are studied by ps–μs transient absorption (TA) and quasi-steady-state photoinduced absorption (PIA) spectroscopy. The three cyclopentadithiophene-based photosensitizer dye molecules exhibit comparably low power conversion efficiencies ranging from 0.8% to 1.7% in solid-state DSSCs. We find that the photocurrents increase in the presence of Li-salt additives. Both TA and PIA measurements observe long-lived dye cations created by electron injection from the dyes’ excited state for two dyes from the series. However, the third dye shows significantly lower performance as a consequence of the less efficient electron injection even after the addition of Li-salts and faster electron-hole recombination on the ns-μs time scale. In essence, the prerequisites for this class of donor-π bridge-acceptor photosensitizers to reach higher charge generation efficiencies are a combination of strong dipole moments and fine tuning of the electronic landscape at the titania-dye interface by Li-salt addition.

  2. Nutrient cycling and Above- and Below-ground Interactions in a Runoff Agroforestry System Applied with Composted Tree Trimmings

    Science.gov (United States)

    Ilani, Talli; Ephrath, Jhonathan; Silberbush, Moshe; Berliner, Pedro

    2014-05-01

    The primary production in arid zones is limited due to shortage of water and nutrients. Conveying flood water and storing it in plots surrounded by embankments allows their cropping. The efficient exploitation of the stored water can be achieved through an agroforestry system, in which two crops are grown simultaneously: annual crops with a shallow root system and trees with a deeper root system. We posit that the long-term productivity of this system can be maintained by intercropping symbiotic N fixing shrubs with annual crops, and applying the pruned and composted shrub leaves to the soil, thus ensuring an adequate nitrogen level (a limiting factor in drylands) in the soil. To test our hypothesis we carried a two year trial in which fast-growing acacia (A. saligna) trees were the woody component and maize (Zea mays L.) the intercrop. Ten treatments were applied over two maize growth seasons to examine the below- and above-ground effects of tree pruning, compost application and interactions. The addition of compost in the first growth season led to an increase of the soil organic matter reservoir, which was the main N source for the maize during the following growth season. In the second growth season the maize yield was significantly higher in the plots to which compost was applied. Pruning the tree's canopies changed the trees spatial and temporal root development, allowing the annual crop to develop between the trees. The roots of pruned trees intercropped with maize penetrated deeper in the soil. The intercropping of maize within pruned trees and implementing compost resulted in a higher water use efficiency of the water stored in the soil when compared to the not composted and monoculture treatments. The results presented suggest that the approach used in this study can be the basis for achieving sustainable agricultural production under arid conditions.

  3. Uprooting force balance for pioneer woody plants: A quantification of the relative contribution of above- and below-ground plant architecture to uprooting susceptibility

    Science.gov (United States)

    Bywater-Reyes, S.; Wilcox, A. C.; Lightbody, A.; Skorko, K.; Stella, J. C.

    2012-12-01

    Cottonwood (Populus), willow (Salix), and tamarisk (Tamarix) populate riparian areas in many dryland regions, and their recruitment depends heavily on hydrogeomorphic conditions. The survival of pioneer woody seedlings depends in part on the establishment of root systems capable of anchoring plants in subsequent floods, and this root system development in turn influences the cohesion that plants provide to bars. The factors influencing the anchoring ability and resistance to scour of woody seedlings include plant frontal area and flexibility, root structure, and water table elevation. This study aims to quantify the factors comprising the force balance to uproot woody seedlings and saplings in two field sites characterized by different hydrologic conditions. The Bill Williams River (AZ) is an impounded river with elevated water table elevations produced by dam-released base flows. The Bitterroot River (MT) is an unimpounded river with a snowmelt hydrograph and seasonal fluctuations in river and water table elevation. We simulate uprooting from flooding events by saturating substrates and applying force near the base of the plant in a lateral, downstream direction until uprooting occurs, for a range of plant sizes but with a focus on small (plants, with cottonwood and tamarisk seedlings showing greater variability than willow. In contrast, root length and stem diameter are only weakly correlated with pull-out force. By combining pull test results with measurements of geomorphic and groundwater conditions, this study provides insights into the relative contribution of a plant's above-ground and below-ground architecture to uprooting potential and into the feedbacks between vegetation and morphodynamics on river bars.

  4. Quantifying above- and below-ground growth responses of the western Australian oil mallee, Eucalyptus kochii subsp. plenissima, to contrasting decapitation regimes.

    Science.gov (United States)

    Wildy, Dan T; Pate, John S

    2002-08-01

    Resprouting in the oil mallee, Eucalyptus kochii Maiden & Blakely subsp. plenissima Gardner (Brooker), involves generation of new shoots from preformed meristematic foci on the lignotuber. Numbers of such foci escalated from 200 per lignotuber in trees aged 1 year to 3,000 on 4- to 5-year-old trees. Removal of shoot biomass by decapitation 5 cm above ground in summer (February) or spring (October) resulted in initiation of 140-170 new shoots, but approx. 400 shoots were induced to form if crops of new shoots were successively removed until sprouting ceased and rootstocks senesced. Initially, the new shoot biomass of regenerating coppices increased slowly and the root biomass failed to increase appreciably until 1.7-2.5 years after cutting. Newly cut trees showed loss of fine root biomass, and structural roots failed to secondarily thicken to the extent shown by uncut trees. After 2 years, the biomass of shoots of coppiced plants was only one-third that of uncut control trees and shoot:root dry mass ratios of coppiced plants were still low (1.5-2.0) compared with those of the controls (average ratio of 3.1). Spring cutting promoted quicker and greater biomass recovery than summer cutting. Starch in below-ground biomass fell quickly following decapitation and remained low for a 12-18 month period. Utilization of starch reserves in naturally regenerating coppices was estimated to provide only a small proportion of the dry matter accumulated in new shoots. Results are discussed in relation to their impact on coppicing ability of the species under natural conditions or when successively coppiced for shoot biomass production.

  5. Understanding cross-communication between aboveground and belowground tissues via transcriptome analysis of a sucking insect whitefly-infested pepper plants.

    Science.gov (United States)

    Park, Yong-Soon; Ryu, Choong-Min

    2014-01-03

    Plants have developed defensive machinery to protect themselves against herbivore and pathogen attacks. We previously reported that aboveground whitefly (Bemisia tabaci Genn.) infestation elicited induced resistance in leaves and roots and influenced the modification of the rhizosphere microflora. In this study, to obtain molecular evidence supporting these plant fitness strategies against whitefly infestation, we performed a 300 K pepper microarray analysis using leaf and root tissues of pepper (Capsicum annuum L.) applied with whitefly, benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH), and the combination of BTH+whitefly. We defined differentially expressed genes (DEGs) as genes exhibiting more than 2-fold change (1.0 based on log2 values) in expression in leaves and roots in response to each treatment compared to the control. We identified a total of 16,188 DEGs in leaves and roots. Of these, 6685, 6752, and 4045 DEGs from leaf tissue and 6768, 7705, and 7667 DEGs from root tissue were identified in the BTH, BTH+whitefly, and whitefly treatment groups, respectively. The total number of DEGs was approximately two-times higher in roots than in whitefly-infested leaves subjected to whitefly infestation. Among DEGs, whitefly feeding induced salicylic acid and jasmonic acid/ethylene-dependent signaling pathways in leaves and roots. Several transporters and auxin-responsive genes were upregulated in roots, which can explain why biomass increase is facilitated. Using transcriptome analysis, our study provides new insights into the molecular basis of whitefly-mediated intercommunication between aboveground and belowground plant tissues and provides molecular evidence that may explain the alteration of rhizosphere microflora and root biomass by whitefly infestation. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Closing the Knowledge Gap: Effects of Land Use Conversion on Belowground Carbon near the 100th Meridian

    Science.gov (United States)

    Waldron, S. E.; Phillips, R. L.; Dell, R.; Suddick, E. C.

    2012-12-01

    Native prairie of the northern Great Plains near the 100th meridian is currently under land use conversion pressure due to high commodity prices. From 2002 to 2007, approximately 303,515 hectares of prairie were converted to crop production in the Prairie Pothole Region (PPR) from Montana to the Dakotas. The spatiotemporal effects of land-use conversion on soil organic matter are still unclear for the PPR. Effects will vary with management, soil properties and time, making regional experiments and simulation modeling necessary. Grassland conservationists are interested in soil carbon data and soil carbon simulation models to inform potential voluntary carbon credit programs. These programs require quantification of changes in soil carbon associated with land-use conversion and management. We addressed this issue by 1) designing a regional-scale experiment, 2) collecting and analyzing soil data, and 3) interviewing producers about land management practices, as required for regional, process-based biogeochemical models. We selected farms at random within a 29,000 km2 area of interest and measured soil properties at multiple depths for native prairie and adjacent annual crop fields. The cores were processed at six different depths (between 0 and 100 cm) for bulk density, pH, texture, total carbon, inorganic carbon, and total nitrogen. We found that the largest difference in soil organic carbon occurred at the 0-10 cm depth, but the magnitude of the effect of land use varied with soil properties and land management. Results from this project, coupled with regional model simulations (Denitrification-Decomposition, DNDC) represent the baseline data needed for future voluntary carbon credit programs and long-term carbon monitoring networks. Enrollment in such programs could help ranchers and farmers realize a new income stream from maintaining their native prairie and the carbon stored beneath it.

  7. Microspatial ecotone dynamics at a shifting range limit: plant-soil variation across salt marsh-mangrove interfaces.

    Science.gov (United States)

    Yando, E S; Osland, M J; Hester, M W

    2018-05-01

    Ecotone dynamics and shifting range limits can be used to advance our understanding of the ecological implications of future range expansions in response to climate change. In the northern Gulf of Mexico, the salt marsh-mangrove ecotone is an area where range limits and ecotone dynamics can be studied in tandem as recent decreases in winter temperature extremes have allowed for mangrove expansion at the expense of salt marsh. In this study, we assessed aboveground and belowground plant-soil dynamics across the salt marsh-mangrove ecotone quantifying micro-spatial patterns in horizontal extent. Specifically, we studied vegetation and rooting dynamics of large and small trees, the impact of salt marshes (e.g. species and structure) on mangroves, and the influence of vegetation on soil properties along transects from underneath the mangrove canopy into the surrounding salt marsh. Vegetation and rooting dynamics differed in horizontal reach, and there was a positive relationship between mangrove tree height and rooting extent. We found that the horizontal expansion of mangrove roots into salt marsh extended up to eight meters beyond the aboveground boundary. Variation in vegetation structure and local hydrology appear to control mangrove seedling dynamics. Finally, soil carbon density and organic matter did not differ within locations across the salt marsh-mangrove interface. By studying aboveground and belowground variation across the ecotone, we can better predict the ecological effects of continued range expansion in response to climate change.

  8. Microspatial ecotone dynamics at a shifting range limit: plant–soil variation across salt marsh–mangrove interfaces

    Science.gov (United States)

    Yando, Erik S.; Osland, Michael J.; Hester, Mark H.

    2018-01-01

    Ecotone dynamics and shifting range limits can be used to advance our understanding of the ecological implications of future range expansions in response to climate change. In the northern Gulf of Mexico, the salt marsh–mangrove ecotone is an area where range limits and ecotone dynamics can be studied in tandem as recent decreases in winter temperature extremes have allowed for mangrove expansion at the expense of salt marsh. In this study, we assessed aboveground and belowground plant–soil dynamics across the salt marsh–mangrove ecotone quantifying micro-spatial patterns in horizontal extent. Specifically, we studied vegetation and rooting dynamics of large and small trees, the impact of salt marshes (e.g. species and structure) on mangroves, and the influence of vegetation on soil properties along transects from underneath the mangrove canopy into the surrounding salt marsh. Vegetation and rooting dynamics differed in horizontal reach, and there was a positive relationship between mangrove tree height and rooting extent. We found that the horizontal expansion of mangrove roots into salt marsh extended up to eight meters beyond the aboveground boundary. Variation in vegetation structure and local hydrology appear to control mangrove seedling dynamics. Finally, soil carbon density and organic matter did not differ within locations across the salt marsh-mangrove interface. By studying aboveground and belowground variation across the ecotone, we can better predict the ecological effects of continued range expansion in response to climate change.

  9. Interference and memory capacity limitations.

    Science.gov (United States)

    Endress, Ansgar D; Szabó, Szilárd

    2017-10-01

    Working memory (WM) is thought to have a fixed and limited capacity. However, the origins of these capacity limitations are debated, and generally attributed to active, attentional processes. Here, we show that the existence of interference among items in memory mathematically guarantees fixed and limited capacity limits under very general conditions, irrespective of any processing assumptions. Assuming that interference (a) increases with the number of interfering items and (b) brings memory performance to chance levels for large numbers of interfering items, capacity limits are a simple function of the relative influence of memorization and interference. In contrast, we show that time-based memory limitations do not lead to fixed memory capacity limitations that are independent of the timing properties of an experiment. We show that interference can mimic both slot-like and continuous resource-like memory limitations, suggesting that these types of memory performance might not be as different as commonly believed. We speculate that slot-like WM limitations might arise from crowding-like phenomena in memory when participants have to retrieve items. Further, based on earlier research on parallel attention and enumeration, we suggest that crowding-like phenomena might be a common reason for the 3 major cognitive capacity limitations. As suggested by Miller (1956) and Cowan (2001), these capacity limitations might arise because of a common reason, even though they likely rely on distinct processes. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  10. The distribution of naturally occurring radionuclides from ores processing to the environment - a case study of milling and treatment of ores for gold in Golden Star Resources of Bogoso Prestea Limited

    International Nuclear Information System (INIS)

    Gbadago, J.K.

    2010-01-01

    This research work was geared towards studying the distribution of naturally occurring radionuclides from the processing stages of oxide and sulphide ores for gold to the critical environment of the Golden Star Resources of Bogoso Prestea Limited in the Western region of Ghana. The study was carried out by measuring the natural radionuclide contents of raw feed ore and pulp samples from physical and chemical processing stages of oxide and sulphide ore treatment plants; tailings; de-silted sediments of a run-off from the tailings dam vicinity through a critical community and; soils and drinking water from the critical community. Also, as part of a comprehensive approach, the geochemical compositions were measured to determine any possible influence on the radionuclide distributions. Amongst the radionuclide decay chains, 238 U-series were the dominant throughout all the measurements. However, the concentrations are lower than the world permissible limits. The indicative doses associated with the activity concentration distributions in the processed feed ores at various processing stages ranged from 2 to 70 μSv/y in the oxide plant and from 2 to 108 μSv/y for the sulphide plant. If effective dose of ≤ 10 μSv/y recommended by IAEA for exemption from regulatory control is applied, the processing of ores in the plants must be regulated. However, the estimated annual effective dose received by the workers from any of these stages of operation did not exceed the range of 1-2 mSv recommended by the ICRP-75 (10 μSv/y ≤ Effective dose ≤ 1-2 mSv/y) for the exemption of a practice. This range is far lower than the annual occupational dose limit of 20 mSv/y recommended by IAEA for artificial radioactive sources. Imposing the IAEA recommendation of effective dose of ? 10 μSv/y for exemption from regulatory control of practices could result in many mining and other NORMs industries being regulated without any net benefit in terms of risk reduction. Conversely, Sn, As

  11. The single-process biochemical reaction of Rubisco: a unified theory and model with the effects of irradiance, CO₂ and rate-limiting step on the kinetics of C₃ and C₄ photosynthesis from gas exchange.

    Science.gov (United States)

    Farazdaghi, Hadi

    2011-02-01

    Photosynthesis is the origin of oxygenic life on the planet, and its models are the core of all models of plant biology, agriculture, environmental quality and global climate change. A theory is presented here, based on single process biochemical reactions of Rubisco, recognizing that: In the light, Rubisco activase helps separate Rubisco from the stored ribulose-1,5-bisphosphate (RuBP), activates Rubisco with carbamylation and addition of Mg²(+), and then produces two products, in two steps: (Step 1) Reaction of Rubisco with RuBP produces a Rubisco-enediol complex, which is the carboxylase-oxygenase enzyme (Enco) and (Step 2) Enco captures CO₂ and/or O₂ and produces intermediate products leading to production and release of 3-phosphoglycerate (PGA) and Rubisco. PGA interactively controls (1) the carboxylation-oxygenation, (2) electron transport, and (3) triosephosphate pathway of the Calvin-Benson cycle that leads to the release of glucose and regeneration of RuBP. Initially, the total enzyme participates in the two steps of the reaction transitionally and its rate follows Michaelis-Menten kinetics. But, for a continuous steady state, Rubisco must be divided into two concurrently active segments for the two steps. This causes a deviation of the steady state from the transitional rate. Kinetic models are developed that integrate the transitional and the steady state reactions. They are tested and successfully validated with verifiable experimental data. The single-process theory is compared to the widely used two-process theory of Farquhar et al. (1980. Planta 149, 78-90), which assumes that the carboxylation rate is either Rubisco-limited at low CO₂ levels such as CO₂ compensation point, or RuBP regeneration-limited at high CO₂. Since the photosynthesis rate cannot increase beyond the two-process theory's Rubisco limit at the CO₂ compensation point, net photosynthesis cannot increase above zero in daylight, and since there is always respiration at

  12. Isometric scaling of above- and below-ground biomass at the individual and community levels in the understorey of a sub-tropical forest.

    Science.gov (United States)

    Cheng, Dongliang; Zhong, Quanlin; Niklas, Karl J; Ma, Yuzhu; Yang, Yusheng; Zhang, Jianhua

    2015-02-01

    Empirical studies and allometric partitioning (AP) theory indicate that plant above-ground biomass (MA) scales, on average, one-to-one (isometrically) with below-ground biomass (MR) at the level of individual trees and at the level of entire forest communities. However, the ability of the AP theory to predict the biomass allocation patterns of understorey plants has not been established because most previous empirical tests have focused on canopy tree species or very large shrubs. In order to test the AP theory further, 1586 understorey sub-tropical forest plants from 30 sites in south-east China were harvested and examined. The numerical values of the scaling exponents and normalization constants (i.e. slopes and y-intercepts, respectively) of log-log linear MA vs. MR relationships were determined for all individual plants, for each site, across the entire data set, and for data sorted into a total of 19 sub-sets of forest types and successional stages. Similar comparisons of MA/MR were also made. The data revealed that the mean MA/MR of understorey plants was 2·44 and 1·57 across all 1586 plants and for all communities, respectively, and MA scaled nearly isometrically with respect to MR, with scaling exponents of 1·01 for all individual plants and 0·99 for all communities. The scaling exponents did not differ significantly among different forest types or successional stages, but the normalization constants did, and were positively correlated with MA/MR and negatively correlated with scaling exponents across all 1586 plants. The results support the AP theory's prediction that MA scales nearly one-to-one with MR (i.e. MA ∝ MR (≈1·0)) and that plant biomass partitioning for individual plants and at the community level share a strikingly similar pattern, at least for the understorey plants examined in this study. Furthermore, variation in environmental conditions appears to affect the numerical values of normalization constants, but not the scaling exponents

  13. Diversity and Spatial Structure of Belowground Plant–Fungal Symbiosis in a Mixed Subtropical Forest of Ectomycorrhizal and Arbuscular Mycorrhizal Plants

    Science.gov (United States)

    Toju, Hirokazu; Sato, Hirotoshi; Tanabe, Akifumi S.

    2014-01-01

    Plant–mycorrhizal fungal interactions are ubiquitous in forest ecosystems. While ectomycorrhizal plants and their fungi generally dominate temperate forests, arbuscular mycorrhizal symbiosis is common in the tropics. In subtropical regions, however, ectomycorrhizal and arbuscular mycorrhizal plants co-occur at comparable abundances in single forests, presumably generating complex community structures of root-associated fungi. To reveal root-associated fungal community structure in a mixed forest of ectomycorrhizal and arbuscular mycorrhizal plants, we conducted a massively-parallel pyrosequencing analysis, targeting fungi in the roots of 36 plant species that co-occur in a subtropical forest. In total, 580 fungal operational taxonomic units were detected, of which 132 and 58 were probably ectomycorrhizal and arbuscular mycorrhizal, respectively. As expected, the composition of fungal symbionts differed between fagaceous (ectomycorrhizal) and non-fagaceous (possibly arbuscular mycorrhizal) plants. However, non-fagaceous plants were associated with not only arbuscular mycorrhizal fungi but also several clades of ectomycorrhizal (e.g., Russula) and root-endophytic ascomycete fungi. Many of the ectomycorrhizal and root-endophytic fungi were detected from both fagaceous and non-fagaceous plants in the community. Interestingly, ectomycorrhizal and arbuscular mycorrhizal fungi were concurrently detected from tiny root fragments of non-fagaceous plants. The plant–fungal associations in the forest were spatially structured, and non-fagaceous plant roots hosted ectomycorrhizal fungi more often in the proximity of ectomycorrhizal plant roots. Overall, this study suggests that belowground plant–fungal symbiosis in subtropical forests is complex in that it includes “non-typical” plant–fungal combinations (e.g., ectomycorrhizal fungi on possibly arbuscular mycorrhizal plants) that do not fall within the conventional classification of mycorrhizal symbioses, and in

  14. Diversity and spatial structure of belowground plant-fungal symbiosis in a mixed subtropical forest of ectomycorrhizal and arbuscular mycorrhizal plants.

    Science.gov (United States)

    Toju, Hirokazu; Sato, Hirotoshi; Tanabe, Akifumi S

    2014-01-01

    Plant-mycorrhizal fungal interactions are ubiquitous in forest ecosystems. While ectomycorrhizal plants and their fungi generally dominate temperate forests, arbuscular mycorrhizal symbiosis is common in the tropics. In subtropical regions, however, ectomycorrhizal and arbuscular mycorrhizal plants co-occur at comparable abundances in single forests, presumably generating complex community structures of root-associated fungi. To reveal root-associated fungal community structure in a mixed forest of ectomycorrhizal and arbuscular mycorrhizal plants, we conducted a massively-parallel pyrosequencing analysis, targeting fungi in the roots of 36 plant species that co-occur in a subtropical forest. In total, 580 fungal operational taxonomic units were detected, of which 132 and 58 were probably ectomycorrhizal and arbuscular mycorrhizal, respectively. As expected, the composition of fungal symbionts differed between fagaceous (ectomycorrhizal) and non-fagaceous (possibly arbuscular mycorrhizal) plants. However, non-fagaceous plants were associated with not only arbuscular mycorrhizal fungi but also several clades of ectomycorrhizal (e.g., Russula) and root-endophytic ascomycete fungi. Many of the ectomycorrhizal and root-endophytic fungi were detected from both fagaceous and non-fagaceous plants in the community. Interestingly, ectomycorrhizal and arbuscular mycorrhizal fungi were concurrently detected from tiny root fragments of non-fagaceous plants. The plant-fungal associations in the forest were spatially structured, and non-fagaceous plant roots hosted ectomycorrhizal fungi more often in the proximity of ectomycorrhizal plant roots. Overall, this study suggests that belowground plant-fungal symbiosis in subtropical forests is complex in that it includes "non-typical" plant-fungal combinations (e.g., ectomycorrhizal fungi on possibly arbuscular mycorrhizal plants) that do not fall within the conventional classification of mycorrhizal symbioses, and in that

  15. Belowground dynamics in mangrove ecosystems

    Science.gov (United States)

    McKee, Karen L.

    2004-01-01

    Mangrove ecosystems are tropical/subtropical communities of primarily tree species that grow in the intertidal zone. These tidal communities are important coastal ecosystems that are valued for a variety of ecological and societal goods and services (fig. 1). Mangrove wetlands are important filters of materials moving between the land and sea, trapping sediment, nutrients, and pollutants in runoff from uplands and preventing their direct introduction into sensitive marine ecosystems such as seagrass beds and coral reefs. Mangroves serve as nursery grounds and refuge for a variety of organisms and are consequently vital to the biological productivity of coastal waters. Furthermore, because mangroves are highly resilient to disturbances such as hurricanes, they represent a self-sustaining, protective barrier for human populations living in the coastal zone. Mangrove ecosystems also contribute to shoreline stabilization through consolidation of unstable mineral sediments and peat formation. In order to help conserve mangrove ecoystems, scientists with the United States Geological Survey (USGS) at the National Wetlands Research Center are working to more fully understand the dynamics that impact these vital ecosystems.

  16. Limitations of Boltzmann's principle

    International Nuclear Information System (INIS)

    Lavenda, B.H.

    1995-01-01

    The usual form of Boltzmann's principle assures that maximum entropy, or entropy reduction, occurs with maximum probability, implying a unimodal distribution. Boltzmann's principle cannot be applied to nonunimodal distributions, like the arcsine law, because the entropy may be concave only over a limited portion of the interval. The method of subordination shows that the arcsine distribution corresponds to a process with a single degree of freedom, thereby confirming the invalidation of Boltzmann's principle. The fractalization of time leads to a new distribution in which arcsine and Cauchy distributions can coexist simultaneously for nonintegral degrees of freedom between √2 and 2

  17. Marketing with limited budget

    OpenAIRE

    Smirnova, Daria

    2017-01-01

    The purpose of this research-based thesis was to get an idea how managers of two small resembling hotels of a specific region deal with marketing process with a limited budget. In addition, the aim of the thesis was to examine if hotel managers who were interviewed perceive marketing only in the way of ‘promotion’ rather than marketing research, marketing mix and marketing environment theories. It was also found out if hotel managers of those hotels consider marketing as a key to successful h...

  18. Growth potential limits drought morphological plasticity in seedlings from six Eucalyptus provenances.

    Science.gov (United States)

    Maseda, Pablo H; Fernández, Roberto J

    2016-02-01

    Water stress modifies plant above- vs belowground biomass allocation, i.e., morphological plasticity. It is known that all species and genotypes reduce their growth rate in response to stress, but in the case of water stress it is unclear whether the magnitude of such reduction is linked to the genotype's growth potential, and whether the reduction can be largely attributed to morphological adjustments such as plant allocation and leaf and root anatomy. We subjected seedlings of six seed sources, three from each of Eucalyptus camaldulensis (potentially fast growing) and E. globulus (inherently slow growing), to three experimental water regimes. Biomass, leaf area and root length were measured in a 6-month glasshouse experiment. We then performed functional growth analysis of relative growth rate (RGR), and aboveground (leaf area ratio (LAR), specific leaf area (SLA) and leaf mass ratio (LMR)) and belowground (root length ratio (RLR), specific root length (SRL) and root mass ratio (RMR)) morphological components. Total biomass, root biomass and leaf area were reduced for all Eucalyptus provenances according to drought intensity. All populations exhibited drought plasticity, while those of greater growth potential (RGRmax) had a larger reduction in growth (discounting the effect of size). A positive correlation was observed between drought sensitivity and RGRmax. Aboveground, drought reduced LAR and LMR; under severe drought a negative correlation was found between LMR and RGRmax. Belowground, drought reduced SRL but increased RMR, resulting in no change in RLR. Under severe drought, a negative correlation was found between RLR, SRL and RGRmax. Our evidence strongly supports the classic ecophysiological trade-off between growth potential and drought tolerance for woody seedlings. It also suggests that slow growers would have a low capacity to adjust their morphology. For shoots, this constraint on plasticity was best observed in partition (i.e., LMR) whereas for

  19. Limites do cuidado: representações e processos inconscientes sobre a população na porta de entrada de um hospital de emergência Health care limits: representations and unconscious processes related to the population at the hospital emergency entrance

    Directory of Open Access Journals (Sweden)

    Marilene de Castilho Sá

    2008-06-01

    Full Text Available Este artigo apresenta parte dos resultados de uma investigação voltada para a análise dos limites e possibilidades que os processos intersubjetivos e inconscientes presentes nos serviços de saúde estabelecem para o exercício da solidariedade, para a cooperação e para a produção do cuidado com a vida. Elegeu-se como estudo de caso um hospital público de emergência, situado no Município do Rio de Janeiro, Brasil. A Psicossociologia francesa, de inspiração clínica psicanalítica, a teoria psicanalítica sobre os processos intersubjetivos e grupais e a Psicodinâmica do Trabalho são os referenciais centrais que orientaram o desenho da investigação e a análise do material empírico. As representações psíquicas e os processos inconscientes relativos à população e suas demandas, produzidos pelos trabalhadores de saúde do hospital estudado, foram analisados, discutindo-se suas conseqüências sobre a produção do cuidado. Algumas imagens se destacaram, como a "carência", utilizada como uma categoria encobridora da diversidade da demanda, num processo inconsciente de múltiplas reduções: da negação do sofrimento social à negação da condição de humanidade dos pacientes.This article presents some results from a study aimed at analyzing the limits and possibilities defined by inter-subjective and unconscious processes of solidarity, cooperation, and life care production in health services. A public hospital with an emergency department in the city of Rio de Janeiro, Brazil, was selected as a case study. The French school of psychosociology, oriented by the psychoanalytical clinical approach, the psychoanalytical theory on inter-subjective and group processes, and work psychodynamics provided the basis for the study's methodological strategies and analysis of the results. The study analyzed health professionals' psychological representations and unconscious processes related to emergency department users and their

  20. Limitations of inclusive fitness.

    Science.gov (United States)

    Allen, Benjamin; Nowak, Martin A; Wilson, Edward O

    2013-12-10

    Until recently, inclusive fitness has been widely accepted as a general method to explain the evolution of social behavior. Affirming and expanding earlier criticism, we demonstrate that inclusive fitness is instead a limited concept, which exists only for a small subset of evolutionary processes. Inclusive fitness assumes that personal fitness is the sum of additive components caused by individual actions. This assumption does not hold for the majority of evolutionary processes or scenarios. To sidestep this limitation, inclusive fitness theorists have proposed a method using linear regression. On the basis of this method, it is claimed that inclusive fitness theory (i) predicts the direction of allele frequency changes, (ii) reveals the reasons for these changes, (iii) is as general as natural selection, and (iv) provides a universal design principle for evolution. In this paper we evaluate these claims, and show that all of them are unfounded. If the objective is to analyze whether mutations that modify social behavior are favored or opposed by natural selection, then no aspect of inclusive fitness theory is needed.

  1. Impacts of afforestation and silviculture on the soil C balance of tropical tree plantations: belowground C allocation, soil CO2 efflux and C accretion (Invited)

    Science.gov (United States)

    Epron, D.; Koutika, L.; Mareschal, L.; Nouvellon, Y.

    2013-12-01

    Tropical forest plantations will provide a large part of the global wood supply which is anticipated to increase sharply in the next decades, becoming a valuable source of income in many countries, where they also contribute to land use changes that impact the global carbon (C) cycle. Tropical forest plantations established on previous grasslands are potential C sinks offsetting anthropogenic CO2 emissions. When they are managed on short rotations, the aboveground biomass is frequently removed and transformed into wood products with short lifetimes. The soil is thus the only compartment for durable C sequestration. The soil C budget results from the inputs of C from litterfall, root turnover and residues left at logging stage, balanced by C losses through heterotrophic respiration and leaching of organic C with water flow. Intensive researches have been conducted these last ten years in eucalypt plantations in the Congo on the effects of management options on soil fertility improvement and C sequestration. Our aim is to review important results regarding belowground C allocation, soil CO2 efflux and C accretion in relation to management options. We will specifically address (i) the soil C dynamics after afforestation of a tropical savannah, (ii) the impact of post-harvest residue management, and (iii) the beneficial effect of introducing nitrogen fixing species for C sequestration. Our results on afforestation of previous savannah showed that mechanical soil disturbance for site preparation had no effect on soil CO2 efflux and soil C balance. Soil C increased after afforestation despite a rapid disappearance of the labile savannah-derived C because a large fraction of savannah-derived C is stable and the aboveground litter layer is as the major source of CO2 contributing to soil CO2 efflux. We further demonstrated that the C stock in and on the soil slightly increased after each rotation when large amounts of residues are left at logging stage and that most of

  2. Strategic arms limitation

    Science.gov (United States)

    Allen Greb, G.; Johnson, Gerald W.

    1983-10-01

    Following World War II, American scientists and politicians proposed in the Baruch plan a radical solution to the problem of nuclear weapons: to eliminate them forever under the auspices of an international nuclear development authority. The Soviets, who as yet did not possess the bomb, rejected this plan. Another approach suggested by Secretary of War Henry Stimson to negotiate directly with the Soviet Union was not accepted by the American leadership. These initial arms limitation failures both reflected and exacerbated the hostile political relationship of the superpowers in the 1950s and 1960s. Since 1969, the more modest focus of the Soviet-American arms control process has been on limiting the numbers and sizes of both defensive and offensive strategic systems. The format for this effort has been the Strategic Arms Limitatins Talks (Salt) and more recently the Strategic Arms Reduction Talks (START). Both sides came to these negotiations convinced that nuclear arsenals had grown so large that some for of mutual restraint was needed. Although the SALT/START process has been slow and ponderous, it has produced several concrete the agreements and collateral benefits. The 1972 ABM Treaty restricts the deployment of ballistic missile defense systems, the 1972 Interim Agreement places a quantitative freeze on each side's land based and sea based strategic launchers, and the as yet unratified 1979 SALT II Treaty sets numerical limits on all offensive strategic systems and sublimits on MIRVed systems. Collateral benefits include improved verification procedures, working definitions and counting rules, and permanent bureaucratic apparatus which enhance stability and increase the chances for achieving additional agreements.

  3. Anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure in a single continuously stirred tank reactor process: Limits in co-substrate ratios and organic loading rate.

    Science.gov (United States)

    Rico, Carlos; Muñoz, Noelia; Rico, José Luis

    2015-01-01

    Mesophilic anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure was investigated with the aim of determining the treatment limits in terms of the cheese whey fraction in feed and the organic loading rate. The results of a continuous stirred tank reactor that was operated with a hydraulic retention time of 15.6 days showed that the co-digestion process was possible with a cheese whey fraction as high as 85% in the feed. The efficiency of the process was similar within the range of the 15-85% cheese whey fraction. To study the effect of the increasing loading rate, the HRT was progressively shortened with the 65% cheese whey fraction in the feed. The reactor efficiency dropped as the HRT decreased but enabled a stable operation over 8.7 days of HRT. At these operating conditions, a volumetric methane production rate of 1.37 m(3) CH4 m(-3) d(-1) was achieved. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Partnerships – Limited partnerships and limited liability limited partnerships

    OpenAIRE

    Henning, Johan J.

    2000-01-01

    Consideration of the Limited Liability Partnership Act 2000 which introduced a new corporate entity, carrying the designations “partnership” and “limited” which allow members to limit their liability whilst organising themselves internally as a partnership. Article by Professor Johan Henning (Director of the Centre for Corporate Law and Practice, IALS and Dean of the Faculty of Law, University of the Free State, South Africa). Published in Amicus Curiae - Journal of the Institute of Advanced ...

  5. “I have surly passed a limit, it is simply too much”: women’s and men’s experiences of stress and wellbeing when living within a process of housework resignation

    Directory of Open Access Journals (Sweden)

    Lisa Harryson

    2016-03-01

    Full Text Available Abstract Background Gender inequality within paid and unpaid work exposes women and men to different environments and responsibilities. These gender patterns shape living conditions for women and men, either negatively or positively, by affecting the prospect of good health. Most public health studies of gender and housework are quantitative, and knowledge about the relationship between housework experiences and health for women and men is limited. The aim of this study was to explore the housework experiences and practices of women and men and their experiences of stress and perceived wellbeing from a gender perspective. Methods We conducted thematic interviews with four women and four men living in Sweden, and performed an analysis using the Grounded Theory method. Findings We found that stereotypical gender practices in housework influenced experiences of stress and perceived wellbeing among women and men. Despite proposing gender equality in housework as a means of improving wellbeing, inequality was amplified by the way women and men handle the gendered division of housework. We call this recurring theme “The process of housework resignation”, which also constitute the core category in our analysis. “The process of housework resignation” was theorised from the categories “Gender practices in housework”, “Experiencing stress and wellbeing” and “Managing daily life”. Conclusions Stereotypical gender practices in housework can increase experiences of stress among women and men. Challenging stereotypical masculinities can be a key for breaking the process of resignation in housework and for facilitating improved health among both women and men in heterosexual couple relationships within a Swedish context.

  6. HOME Income Limits

    Data.gov (United States)

    Department of Housing and Urban Development — HOME Income Limits are calculated using the same methodology that HUD uses for calculating the income limits for the Section 8 program. These limits are based on HUD...

  7. Limits to biofuels

    Directory of Open Access Journals (Sweden)

    Johansson S.

    2013-06-01

    Full Text Available Biofuel production is dependent upon agriculture and forestry systems, and the expectations of future biofuel potential are high. A study of the global food production and biofuel production from edible crops implies that biofuel produced from edible parts of crops lead to a global deficit of food. This is rather well known, which is why there is a strong urge to develop biofuel systems that make use of residues or products from forest to eliminate competition with food production. However, biofuel from agro-residues still depend upon the crop production system, and there are many parameters to deal with in order to investigate the sustainability of biofuel production. There is a theoretical limit to how much biofuel can be achieved globally from agro-residues and this amounts to approximately one third of todays’ use of fossil fuels in the transport sector. In reality this theoretical potential may be eliminated by the energy use in the biomass-conversion technologies and production systems, depending on what type of assessment method is used. By surveying existing studies on biofuel conversion the theoretical limit of biofuels from 2010 years’ agricultural production was found to be either non-existent due to energy consumption in the conversion process, or up to 2–6000TWh (biogas from residues and waste and ethanol from woody biomass in the more optimistic cases.

  8. Limits to biofuels

    Science.gov (United States)

    Johansson, S.

    2013-06-01

    Biofuel production is dependent upon agriculture and forestry systems, and the expectations of future biofuel potential are high. A study of the global food production and biofuel production from edible crops implies that biofuel produced from edible parts of crops lead to a global deficit of food. This is rather well known, which is why there is a strong urge to develop biofuel systems that make use of residues or products from forest to eliminate competition with food production. However, biofuel from agro-residues still depend upon the crop production system, and there are many parameters to deal with in order to investigate the sustainability of biofuel production. There is a theoretical limit to how much biofuel can be achieved globally from agro-residues and this amounts to approximately one third of todays' use of fossil fuels in the transport sector. In reality this theoretical potential may be eliminated by the energy use in the biomass-conversion technologies and production systems, depending on what type of assessment method is used. By surveying existing studies on biofuel conversion the theoretical limit of biofuels from 2010 years' agricultural production was found to be either non-existent due to energy consumption in the conversion process, or up to 2-6000TWh (biogas from residues and waste and ethanol from woody biomass) in the more optimistic cases.

  9. Limit theorems for functionals of Gaussian vectors

    Institute of Scientific and Technical Information of China (English)

    Hongshuai DAI; Guangjun SHEN; Lingtao KONG

    2017-01-01

    Operator self-similar processes,as an extension of self-similar processes,have been studied extensively.In this work,we study limit theorems for functionals of Gaussian vectors.Under some conditions,we determine that the limit of partial sums of functionals of a stationary Gaussian sequence of random vectors is an operator self-similar process.

  10. Limits on fundamental limits to computation.

    Science.gov (United States)

    Markov, Igor L

    2014-08-14

    An indispensable part of our personal and working lives, computing has also become essential to industries and governments. Steady improvements in computer hardware have been supported by periodic doubling of transistor densities in integrated circuits over the past fifty years. Such Moore scaling now requires ever-increasing efforts, stimulating research in alternative hardware and stirring controversy. To help evaluate emerging technologies and increase our understanding of integrated-circuit scaling, here I review fundamental limits to computation in the areas of manufacturing, energy, physical space, design and verification effort, and algorithms. To outline what is achievable in principle and in practice, I recapitulate how some limits were circumvented, and compare loose and tight limits. Engineering difficulties encountered by emerging technologies may indicate yet unknown limits.

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

    Science.gov (United States)

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

    2017-12-01

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

  12. Functional Limitations in Severe Haemophilia

    NARCIS (Netherlands)

    Genderen, F.R. van

    2006-01-01

    This thesis aims to describe the Disablement Process (DP) in Dutch adult patients with severe haemophilia, with specific focus on the domain of “Functional Limitations”. Four main questions underlie this thesis: How can Functional Limitations in severe haemophilia be investigated? Can the

  13. Landscape genetics and limiting factors

    Science.gov (United States)

    Samuel A. Cushman; Andrew J. Shirk; Erin L. Landguth

    2013-01-01

    Population connectivity is mediated by the movement of organisms or propagules through landscapes. However, little is known about how variation in the pattern of landscape mosaics affects the detectability of landscape genetic relationships. The goal of this paper is to explore the impacts of limiting factors on landscape genetic processes using simulation...

  14. Limits on light Higgs bosons

    International Nuclear Information System (INIS)

    Dawson, S.

    1988-01-01

    Experimental limits on light Higgs bosons (M/sub H/ < 5 GeV) are examined. Particular attention is paid to the process K → πH. It is shown that there may be an allowed window for light Higgs bosons between about 100 and 210 MeV. 13 refs., 2 figs

  15. Fuel processing. Wastes processing

    International Nuclear Information System (INIS)

    Bourgeois, M.

    2000-01-01

    The gaseous, liquid and solid radioactive effluents generated by the fuel reprocessing, can't be release in the environment. They have to be treated in order to respect the limits of the pollution regulations. These processing are detailed and discussed in this technical paper. A second part is devoted to the SPIN research program relative to the separation of the long life radionuclides in order to reduce the radioactive wastes storage volume. (A.L.B.)

  16. Limit, breakthrough and prosperity

    International Nuclear Information System (INIS)

    Takahashi, Minoru

    1973-01-01

    It is pointed out that the flow toward serious crises is in progress with regard to energy and industrial problems. Technical and industrial preparation and countermeasure to the flow are proposed, and the existence of a certain new world attainable on the assumption that the countermeasure is successful is described. The relation between oil output and the increasing demand for energy is pointed out as a subject matter of the crisis. The contribution of oil energy to total energy, after the output turns to decreasing process, decreases by 177.87x10 6 tons (converted to coal at the rate 6848 kcal/kg) per year at maximum. Converted to the GNP of the world, this becomes (425 dollar/ton x 177.87 x 10 6 ton=75.6 x 10 9 dollar). This fluctuation width in a year must be compensated by the change of industrial structure and energy supplying means. The countermeasure and preparation are proposed from the viewpoints of the energy and the industrial structure in which nuclear power generation plays important role. The largest production on the earth limited by energy consumption and the temperature balance on the earth is investigated, and the perspective in the future is given. (Yamamoto, Y.)

  17. What value, detection limits

    International Nuclear Information System (INIS)

    Currie, L.A.

    1986-01-01

    Specific approaches and applications of LLD's to nuclear and ''nuclear-related'' measurements are presented in connection with work undertaken for the U.S. Nuclear Regulatory Commission and the International Atomic Energy Agency. In this work, special attention was given to assumptions and potential error sources, as well as to different types of analysis. For the former, the authors considered random and systematic error associated with the blank and the calibration and sample preparation processes, as well as issues relating to the nature of the random error distributions. Analysis types considered included continuous monitoring, ''simple counting'' involving scalar quantities, and spectrum fitting involving data vectors. The investigation of data matrices and multivariate analysis is also described. The most important conclusions derived from this study are: that there is a significant lack of communication and compatibility resulting from diverse terminology and conceptual bases - including no-basis ''ad hoc'' definitions; that the distinction between detection decisions and detection limits is frequently lost sight of; and that quite erroneous LOD estimates follow from inadequate consideration of the actual variability of the blank, and systematic error associated with the blank, the calibration-recovery factor, matrix effects, and ''black box'' data reduction models

  18. LANSCE beam current limiter

    International Nuclear Information System (INIS)

    Gallegos, F.R.

    1996-01-01

    The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. Active instrumentation, such as the Beam Current Limiter, is a component of the RSS. The current limiter is designed to limit the average current in a beam line below a specific level, thus minimizing the maximum current available for a beam spill accident. The beam current limiter is a self-contained, electrically isolated toroidal beam transformer which continuously monitors beam current. It is designed as fail-safe instrumentation. The design philosophy, hardware design, operation, and limitations of the device are described

  19. 7 CFR 1400.204 - Limited partnerships, limited liability partnerships, limited liability companies, corporations...

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Limited partnerships, limited liability partnerships..., limited liability partnerships, limited liability companies, corporations, and other similar legal entities. (a) A limited partnership, limited liability partnership, limited liability company, corporation...

  20. Summary of Dissolved Concentration Limits

    International Nuclear Information System (INIS)

    Yueting Chen

    2001-01-01

    According to the Technical Work Plan titled Technical Work Plan for Waste Form Degradation Process Model Report for SR (CRWMS M and O 2000a), the purpose of this study is to perform abstractions on solubility limits of radioactive elements based on the process-level information and thermodynamic databases provided by Natural Environment Program Operations (NEPO) and Waste Package Operations (WPO). The scope of this analysis is to produce solubility limits as functions, distributions, or constants for all transported radioactive elements identified by the Performance Assessment Operations (PAO) radioisotope screening. Results from an expert elicitation for solubility limits of most radioactive elements were used in the previous Total System Performance Assessments (TSPAs). However, the elicitation conducted in 1993 does not meet the criteria set forth by the U.S. Nuclear Regulatory Commission (NRC) due to lack of documentation and traceability (Kotra et al. 1996, Section 3). Therefore, at the Waste Form Abstraction Workshop held on February 2-4, 1999, at Albuquerque, New Mexico, the Yucca Mountain Site Characterization Project (YMP) decided to develop geochemical models to study solubility for the proposed Monitored Geologic Repository. WPO/NEPO is to develop process-level solubility models, including review and compilation of relevant thermodynamic data. PAO's responsibility is to perform abstractions based on the process models and chemical conditions and to produce solubility distributions or response surfaces applicable to the proposed repository. The results of this analysis and conceptual model will feed the performance assessment for Total System Performance Assessment--Site Recommendation (TSPA-SR) and Total System Performance Assessment--License Application (TSPA-LA), and to the Waste Form Degradation Process Model Report section on concentration limits

  1. Summary of Dissolved Concentration Limits

    Energy Technology Data Exchange (ETDEWEB)

    Yueting Chen

    2001-06-11

    According to the Technical Work Plan titled Technical Work Plan for Waste Form Degradation Process Model Report for SR (CRWMS M&O 2000a), the purpose of this study is to perform abstractions on solubility limits of radioactive elements based on the process-level information and thermodynamic databases provided by Natural Environment Program Operations (NEPO) and Waste Package Operations (WPO). The scope of this analysis is to produce solubility limits as functions, distributions, or constants for all transported radioactive elements identified by the Performance Assessment Operations (PAO) radioisotope screening. Results from an expert elicitation for solubility limits of most radioactive elements were used in the previous Total System Performance Assessments (TSPAs). However, the elicitation conducted in 1993 does not meet the criteria set forth by the U.S. Nuclear Regulatory Commission (NRC) due to lack of documentation and traceability (Kotra et al. 1996, Section 3). Therefore, at the Waste Form Abstraction Workshop held on February 2-4, 1999, at Albuquerque, New Mexico, the Yucca Mountain Site Characterization Project (YMP) decided to develop geochemical models to study solubility for the proposed Monitored Geologic Repository. WPO/NEPO is to develop process-level solubility models, including review and compilation of relevant thermodynamic data. PAO's responsibility is to perform abstractions based on the process models and chemical conditions and to produce solubility distributions or response surfaces applicable to the proposed repository. The results of this analysis and conceptual model will feed the performance assessment for Total System Performance Assessment--Site Recommendation (TSPA-SR) and Total System Performance Assessment--License Application (TSPA-LA), and to the Waste Form Degradation Process Model Report section on concentration limits.

  2. JET pump limiter

    International Nuclear Information System (INIS)

    Sonnenberg, K.; Deksnis, E.; Shaw, R.; Reiter, D.

    1988-01-01

    JET plans to install two pump limiter modules which can be used for belt-limiter, inner-wall and X-point discharges and, also, for 1-2s as the main limiter. A design is presented which is compatible with two diagnostic systems, and which allows partial removal of the pump limiter to provide access for remote-handling operations. The high heat-flux components are initially cooled during a pulse. Heat is removed between discharges by radiation and pressure contacts to a water-cooled support structure. The pumping edge will be made of annealed pyrolytic graphite. Exhaust efficiency has been estimated, for a 1-d edge model, using a Monte-Carlo calculation of neutral gas transport. When the pump limiter is operated together with other wall components we expect an efficiency of ≅ 5% (2.5 x 10 21 part/s). As a main limiter the efficiency increases to about 10%. (author)

  3. Reactor limit control system

    International Nuclear Information System (INIS)

    Rubbel, F.E.

    1982-01-01

    The very extensive use of limitations in the operational field between protection system and closed-loop controls is an important feature of German understanding of operational safety. The design of limitations is based on very large activities in the computational field but mostly on the high level of the plant-wide own commissioning experience of a turnkey contractor. Limitations combine intelligence features of closed-loop controls with the high availability of protection systems. (orig.)

  4. Detector limitations, STAR

    Energy Technology Data Exchange (ETDEWEB)

    Underwood, D. G.

    1998-07-13

    Every detector has limitations in terms of solid angle, particular technologies chosen, cracks due to mechanical structure, etc. If all of the presently planned parts of STAR [Solenoidal Tracker At RHIC] were in place, these factors would not seriously limit our ability to exploit the spin physics possible in RHIC. What is of greater concern at the moment is the construction schedule for components such as the Electromagnetic Calorimeters, and the limited funding for various levels of triggers.

  5. Performance limitations at ISABELLE

    International Nuclear Information System (INIS)

    Keil, E.

    1975-01-01

    The transverse stability of coasting beams in the planned ISABELLE storage rings was studied. The beam--beam tune shift limitation at 0.005 can be avoided, and a computer simulation seems to show 0.005 is a pessimistic limit. For beams of reasonable smoothness on the edge, the actual limit should be somewhat higher. Some coupling effects due to the beam--beam interaction are also examined

  6. Limit loads in nozzles

    International Nuclear Information System (INIS)

    Zouain, N.

    1983-01-01

    The static method for the evaluation of the limit loads of a perfectly elasto-plastic structure is presented. Using the static theorem of Limit Analysis and the Finite Element Method, a lower bound for the colapso load can be obtained through a linear programming problem. This formulation if then applied to symmetrically loaded shells of revolution and some numerical results of limit loads in nozzles are also presented. (Author) [pt

  7. Numerical Limit Analysis:

    DEFF Research Database (Denmark)

    Damkilde, Lars

    2007-01-01

    Limit State analysis has a long history and many prominent researchers have contributed. The theoretical foundation is based on the upper- and lower-bound theorems which give a very comprehensive and elegant formulation on complicated physical problems. In the pre-computer age Limit State analysis...... also enabled engineers to solve practical problems within reinforced concrete, steel structures and geotechnics....

  8. Advanced limiters for ISX

    International Nuclear Information System (INIS)

    Mioduszewski, P.K.; Edmonds, P.H.; Sheffield, J.

    1982-01-01

    Continuous removal of heat and particles becomes a vital necessity in future steady-state fusion devices. The pump limiter seems to be an attractive concept to combine these two tasks. On ISX, various schemes of pump limiters are being explored with the final goal to furnish the ISX--C device with a pump limiter to handle heat removal and particle control in steady state. The emphasis of the present paper is on pump limiters based on ballistic particle collection. If this concept turns out to be successful in supplying sufficient pumping efficiency, it may be possible to design pump limiters without a leading edge. Analytical calculations of the particle collection efficiency are given for various limiter configurations. Pumping efficiencies of approximately 4--10%, depending on the specific configuration, seem to be feasible and should be sufficient for steady-state operation. Initial experimental results on pump limiter studies in ISX--B confirm the calculated collection efficiencies. By measuring the ion saturation current to the limiter blade and the pressure buildup simultaneously, we found a correlation between the incident particle flux and the pressure rise that agrees well with a simple model

  9. Limits to Inclusion

    Science.gov (United States)

    Hansen, Janne Hedegaard

    2012-01-01

    In this article, I will argue that a theoretical identification of the limit to inclusion is needed in the conceptual identification of inclusion. On the one hand, inclusion is formulated as a vision that is, in principle, limitless. On the other hand, there seems to be an agreement that inclusion has a limit in the pedagogical practice. However,…

  10. Mitigating greenhouse: Limited time, limited options

    International Nuclear Information System (INIS)

    Moriarty, Patrick; Honnery, Damon

    2008-01-01

    Most human-caused climate change comes from fossil fuel combustion emissions. To avoid the risk of serious climate change, very recent research suggests that emission reductions will need to be both large and rapidly implemented. We argue that technical solutions-improving energy efficiency, use of renewable and nuclear energy, and carbon capture and sequestration-can only be of minor importance, mainly given the limited time available to take effective climate action. Only curbing energy use, perhaps through 'social efficiency' gains, particularly in the high-energy consumption countries, can provide the rapid emissions reductions needed. The social efficiency approach requires a basic rethinking in how we can satisfy our human needs with low environmental impacts. Large cuts in emissions could then occur rapidly, but only if resistance to such changes can be overcome. Particularly in transport, there are also serious potential conflicts between the technical and the social efficiency approaches, requiring a choice to be made

  11. Moving toroidal limiter

    International Nuclear Information System (INIS)

    Ikuta, Kazunari; Miyahara, Akira.

    1983-06-01

    The concept of the limiter-divertor proposed by Mirnov is extended to a toroidal limiter-divertor (which we call moving toroidal limiter) using the stream of ferromagnetic balls coated with a low Z materials such as plastics, graphite and ceramics. An important advantage of the use of the ferromagnetic materials would be possible soft landing of the balls on a catcher, provided that the temperature of the balls is below Curie point. Moreover, moving toroidal limiter would work as a protector of the first wall not only against the vertical movement of plasma ring but also against the violent inward motion driven by major disruption because the orbit of the ball in the case of moving toroidal limiter distributes over the small major radius side of the toroidal plasma. (author)

  12. Tokamak pump limiters

    International Nuclear Information System (INIS)

    Conn, R.W.

    1984-05-01

    Recent experiments with a scoop limiter without active internal pumping have been carried out in the PDX tokamak with up to 6MW of auxiliary neutral beam heating. Experiments have also been done with a rotating head pump limiter in the PLT tokamak in conjunction with RF plasma heating. Extensive experiments have been done in the ISX-B tokamak and first experiments have been completed with the ALT-I limiter in TEXTOR. The pump limiter modules in these latter two machines have internal getter pumping. Experiments in ISX-B are with ohmic and auxiliary neutral beam heating. The results in ISX-B and TEXTOR show that active density control and particle removal is achieved with pump limiters. In ISX-B, the boundary layer (or scape-off layer) plasma partially screens the core plasma from gas injection. In both ISX-B and TEXTOR, the pressure internal to the module scales linearly with plasma density but in ISX-B, with neutral beam injection, a nonlinear increase is observed at the highest densities studied. Plasma plugging is the suspected cause. Results from PDX suggest that a region may exist in which core plasma energy confinement improves using a pump limiter during neutral beam injection. Asymmetric radial profiles and an increased edge electron temperature are observed in discharges with improved confinement. The injection of small amounts of neon into ISX-B has more clearly shown an improved electron core energy confinement during neutral beam injection. While carried out with a regular limiter, this Z-mode of operation is ideal for use with pump limiters and should be a way to achieve energy confinement times similar to values for H-mode tokamak plasmas. The implication of all these results for the design of a reactor pump limiter is described

  13. Tokamak pump limiters

    International Nuclear Information System (INIS)

    Conn, R.W.; California Univ., Los Angeles

    1984-01-01

    Recent experiments with a scoop limiter without active internal pumping have been carried out in the PDX tokamak with up to 6 MW of auxiliary neutral beam heating. Experiments have also been performed with a rotating head pump limiter in the PLT tokamak in conjunction with RF plasma heating. Extensive experiments have been done in the ISX-B tokamak and first experiments have been completed with the ALT-I limiter in TEXTOR. The pump limiter modules in these latter two machines have internal getter pumping. Experiments in ISX-B are with ohmic and auxiliary neutral beam heating. The results in ISX-B and TEXTOR show that active density control and particle removal is achieved with pump limiters. In ISX-B, the boundary layer (or scrape-off layer) plasma partially screens the core plasma from gas injection. In both ISX-B and TEXTOR, the pressure internal to the module scales linearly with plasma density but in ISX-B, with neutral beam injection, a nonlinear increase is observed at the highest densities studied. Plasma plugging is the suspected cause. Results from PDX suggest that a regime may exist in which core plasma energy confinement improves using a pump limiter during neutral beam injection. Asymmetric radial profiles and an increased edge electron temperature are observed in discharges with improved confinement. The injection of small amounts of neon into ISX-B has more clearly shown an improved electron core energy confinement during neutral beam injection. While carried out with a regular limiter, this 'Z-mode' of operation is ideal for use with pump limiters and should be a way to achieve energy confinement times similar to values for H-mode tokamak plasmas. The implication of all these results for the design of a reactor pump limiter is described. (orig.)

  14. Novel limiter pump topologies

    International Nuclear Information System (INIS)

    Schultz, J.H.

    1981-01-01

    The use of limiter pumps as the principle plasma exhaust system of a magnetic confinement fusion device promises significant simplification, when compared to previously investigating divertor based systems. Further simplifications, such as the integration of the exhaust system with a radio frequency heating system and with the main reactor shield and structure are investigated below. The integrity of limiters in a reactor environment is threatened by many mechanisms, the most severe of which may be erosion by sputtering. Two novel topolgies are suggested which allow high erosion without limiter failure

  15. Novel limiter pump topologies

    International Nuclear Information System (INIS)

    Schultz, J.H.

    1981-01-01

    The use of limiter pumps as the principle plasma exhaust system of a magnetic confinement fusion device promises significant simplification, when compared to previously investigating divertor based systems. Further simplifications, such as the integration of the exhaust system with a radio frequency heating system and with the main reactor shield and structure are investigated below. The integrity of limiters in a reactor environment is threatened by many mechanisms, the most severe of which may be erosion by sputtering. Two novel topologies are suggested which allow high erosion without limiter failure

  16. HUD Program Income Limits

    Data.gov (United States)

    Department of Housing and Urban Development — Income limits used to determine the income eligibility of applicants for assistance under three programs authorized by the National Housing Act. These programs are...

  17. Limited Income and Resources

    Data.gov (United States)

    U.S. Department of Health & Human Services — Information for those with limited income and resources (those who may qualify for or already have the Low Income Subsidy to lower their prescription drug coverage...

  18. SIS - Annual Catch Limit

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Annual Catch Limit (ACL) dataset within the Species Information System (SIS) contains information and data related to management reference points and catch data.

  19. Limited Denial of Participation

    Data.gov (United States)

    Department of Housing and Urban Development — A Limited Denial of Participation (LDP) is an action taken by a HUD Field Office or the Deputy Assistant Secretary for Single Family (DASSF) or Multifamily (DASMF)...

  20. Towards Improved Optical Limiters

    National Research Council Canada - National Science Library

    Huffman, Peter

    2002-01-01

    .... The first approach was to synthesize and study soluble thallium phthalocyanines. Thallium, due to its proximity to lead and indium on the periodic table, should exhibit favorable optical limiting properties...

  1. ACA Federal Upper Limits

    Data.gov (United States)

    U.S. Department of Health & Human Services — Affordable Care Act Federal Upper Limits (FUL) based on the weighted average of the most recently reported monthly average manufacturer price (AMP) for...

  2. HOME Rent Limits

    Data.gov (United States)

    Department of Housing and Urban Development — In accordance with 24 CFR Part 92.252, HUD provides maximum HOME rent limits. The maximum HOME rents are the lesser of: The fair market rent for existing housing for...

  3. Adjusting estimative prediction limits

    OpenAIRE

    Masao Ueki; Kaoru Fueda

    2007-01-01

    This note presents a direct adjustment of the estimative prediction limit to reduce the coverage error from a target value to third-order accuracy. The adjustment is asymptotically equivalent to those of Barndorff-Nielsen & Cox (1994, 1996) and Vidoni (1998). It has a simpler form with a plug-in estimator of the coverage probability of the estimative limit at the target value. Copyright 2007, Oxford University Press.

  4. Smoothness of limit functors

    Indian Academy of Sciences (India)

    Abstract. Let S be a scheme. Assume that we are given an action of the one dimen- sional split torus Gm,S on a smooth affine S-scheme X. We consider the limit (also called attractor) subfunctor Xλ consisting of points whose orbit under the given action. 'admits a limit at 0'. We show that Xλ is representable by a smooth ...

  5. Safety and design limits

    International Nuclear Information System (INIS)

    Shishkov, L. K.; Gorbaev, V. A.; Tsyganov, S. V.

    2007-01-01

    The paper touches upon the issues of NPP safety ensuring at the stage of fuel load design and operation by applying special limitations for a series of parameters, that is, design limits. Two following approaches are compared: the one used by west specialists for the PWR reactor and the Russian approach employed for the WWER reactor. The closeness of approaches is established, differences that are mainly peculiarities of terms are noted (Authors)

  6. Altruism and Reproductive Limitations

    Directory of Open Access Journals (Sweden)

    Carey J. Fitzgerald

    2009-04-01

    Full Text Available We examined how different types of reproductive limitations — functional (schizoid personality disorder and schizophrenia, physical (malnutrition, and sexual (bisexuality and homosexuality — influenced altruistic intentions toward hypothetical target individuals of differing degrees of relatedness (r = 0, .25, and .50. Participants were 312 undergraduate students who completed a questionnaire on altruism toward hypothetical friends, half-siblings, and siblings with these different types of reproductive limitations. Genetic relatedness and reproductive limitations did not influence altruistic decision-making when the cost of altruism was low but did as the cost of altruism increased, with participants being more likely to help a sibling over a half-sibling and a half-sibling over a friend. Participants also indicated they were more likely to help a healthy (control person over people with a reproductive limitation. Of the three types of reproductive limitations, functional limitations had the strongest effect on altruistic decision-making, indicating that people were less likely to help those who exhibit abnormal social behavior.

  7. The variable effects of soil nitrogen availability and insect herbivory on aboveground and belowground plant biomass in an old-field ecosystem

    DEFF Research Database (Denmark)

    Blue, Jarrod D.; Souza, Lara; Classen, Aimée T.

    2011-01-01

    in an old-field ecosystem. In 2004, we established 36 experimental plots in which we manipulated soil nitrogen (N) availability and insect abundance in a completely randomized plot design. In 2009, after 6 years of treatments, we measured aboveground biomass and assessed root production at peak growth...... not be limiting primary production in this ecosystem. Insects reduced the aboveground biomass of subdominant plant species and decreased coarse root production. We found no statistical interactions between N availability and insect herbivory for any response variable. Overall, the results of 6 years of nutrient...

  8. Limiting currents in superconducting composites

    International Nuclear Information System (INIS)

    Keilin, V.E.; Romanovskii, V.R.

    1992-01-01

    In this paper the results of numerical and analytical calculations of the process of current charging into a round superconducting composite with properties homogenized over cross-section are presented. In the numerical solution taken was into account a common proceeding of the thermal and electromagnetic processes. A wire with real volt-ampere characteristics approximated by exponential dependence was considered. The calculations carried out at various rates of current charging, voltampere characteristics, matrix materials, heat transfer coefficients and other parameters showed: the existence of characteristic limiting value of current below which the wire remains in a superconducting state if the current charging ceases and above which changes into a normal state; this current is somewhat less than a quench current; the existence of finite value for limiting current at any low heat transfer from a surface. The analytical solution of the problem is given. It permitted to write the stability criterion from which the dependence of limiting currents on initial parameters follows. The wire nonisothermality, its heat capacity, thermal and electric conductivities are taken into account additionally, as compared to results published earlier

  9. Force Limit System

    Science.gov (United States)

    Pawlik, Ralph; Krause, David; Bremenour, Frank

    2011-01-01

    The Force Limit System (FLS) was developed to protect test specimens from inadvertent overload. The load limit value is fully adjustable by the operator and works independently of the test system control as a mechanical (non-electrical) device. When a test specimen is loaded via an electromechanical or hydraulic test system, a chance of an overload condition exists. An overload applied to a specimen could result in irreparable damage to the specimen and/or fixturing. The FLS restricts the maximum load that an actuator can apply to a test specimen. When testing limited-run test articles or using very expensive fixtures, the use of such a device is highly recommended. Test setups typically use electronic peak protection, which can be the source of overload due to malfunctioning components or the inability to react quickly enough to load spikes. The FLS works independently of the electronic overload protection.

  10. Theory of limit cycles

    CERN Document Server

    Ye, Yan-Qian; Lo, Chi Y

    1986-01-01

    Over the past two decades the theory of limit cycles, especially for quadratic differential systems, has progressed dramatically in China as well as in other countries. This monograph, updating the 1964 first edition, includes these recent developments, as revised by eight of the author's colleagues in their own areas of expertise. The first part of the book deals with limit cycles of general plane stationary systems, including their existence, nonexistence, stability, and uniqueness. The second section discusses the global topological structure of limit cycles and phase-portraits of quadratic systems. Finally, the last section collects important results that could not be included under the subject matter of the previous two sections or that have appeared in the literature very recently. The book as a whole serves as a reference for college seniors, graduate students, and researchers in mathematics and physics.

  11. Hadron collider luminosity limitations

    CERN Document Server

    Evans, Lyndon R

    1992-01-01

    The three colliders operated to date have taught us a great deal about the behaviour of both bunched and debunched beams in storage rings. The main luminosity limitations are now well enough understood that most of them can be stronglu attenuated or eliminated by approriate design precautions. Experience with the beam-beam interaction in both the SPS and the Tevatron allow us to predict the performance of the new generation of colliders with some degree of confidence. One of the main challenges that the accelerator physicist faces is the problem of the dynamic aperture limitations due to the lower field quality expected, imposed by economic and other constraints.

  12. SLC kicker magnet limitations

    International Nuclear Information System (INIS)

    Cassel, R.; Donaldson, A.; Mattison, T.; Bowden, G.; Weaver, J.; Bulos, F.; Fiander, D.

    1991-01-01

    The SLC Damping Ring kicker magnets requires a fast magnetic field rise time of 58 nsec, a peak field of 800 gauss, a pulse amplitude stability of 0.01%, and a reasonable operational lifetime. The original kicker magnets designed by SLAC and at Fermi were not able to fulfill the SLC kicker requirements. Extensive studies were conducted to determine the limitation in the magnets, response of the ferrite in kicker magnet, and the modifications needed to improve the kicker magnet performance. The paper details the SLAC and Fermi kicker magnets limitation of performance

  13. Classical Limit and Quantum Logic

    Science.gov (United States)

    Losada, Marcelo; Fortin, Sebastian; Holik, Federico

    2018-02-01

    The analysis of the classical limit of quantum mechanics usually focuses on the state of the system. The general idea is to explain the disappearance of the interference terms of quantum states appealing to the decoherence process induced by the environment. However, in these approaches it is not explained how the structure of quantum properties becomes classical. In this paper, we consider the classical limit from a different perspective. We consider the set of properties of a quantum system and we study the quantum-to-classical transition of its logical structure. The aim is to open the door to a new study based on dynamical logics, that is, logics that change over time. In particular, we appeal to the notion of hybrid logics to describe semiclassical systems. Moreover, we consider systems with many characteristic decoherence times, whose sublattices of properties become distributive at different times.

  14. Engineering Options Assessment Report. Nitrate Salt Waste Stream Processing

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-13

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 above-ground UNS, and 79 candidate below-ground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  15. Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-18

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 aboveground UNS, and 79 candidate belowground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  16. Challenges for injection systems and combustion processes of large diesel engines for keeping the emission limits IMO TIER3 in 2016; Herausforderungen bei Einspritzsystemen und Brennverfahren von Grossdieselmotoren zur Einhaltung der Emissionsgrenzwerte IMO TIER3 in 2016

    Energy Technology Data Exchange (ETDEWEB)

    Harndorf, Horst; Rabe, Jean Rom; Wichmann, Volker; Fink, Christian [Rostock Univ. (Germany). Lehrstuhl fuer Kolbenmaschinen und Verbrennungsmotoren; Buchholz, Bert [Forschungszentrum Thermodynamik und Verbrennungsmotoren Rostock GmbH, Rostock (Germany)

    2011-07-01

    More stringent emission limits for large engines are dominating research and development activities of engine and component manufacturers during the next years. This is especially the case with respect to the introduction of the IMO-TIER 3 limits in the emission control areas in 2016. Then a reduction of nitrogen oxides emissions of roughly 80% compared to today is required. In particular in combination with new regulations on the fuel sulfur content or on the sulfur oxide emissions respectively totally new technological approaches have to be applied to marine diesel engines and their periphery. Technical solutions based on exhaust gas treatment like SCR-catalysts or sulfur scrubbers as well as exhaust gas recirculation concepts are discussed in this paper. Depending on the specific method there is a need to handle different operating materials such as heavy fuel oil, distillate fuels, urea solution, caustic soda lye or lime. Furthermore specific challenges for the development and application of advanced fuel injection systems and injection strategies are mentioned. It is to be assumed that several emission reduction concepts will be available in 2016. Depending on the skip type and the characteristic deployment an optimum concept has to be selected. Because of the complexity of the different technologies strong repercussions are implied on the ship layout and marine engine operation. (orig.)

  17. Activation analysis. Detection limits

    International Nuclear Information System (INIS)

    Revel, G.

    1999-01-01

    Numerical data and limits of detection related to the four irradiation modes, often used in activation analysis (reactor neutrons, 14 MeV neutrons, photon gamma and charged particles) are presented here. The technical presentation of the activation analysis is detailed in the paper P 2565 of Techniques de l'Ingenieur. (A.L.B.)

  18. The Copyright Agency Limited.

    Science.gov (United States)

    Morgan, Caroline

    1993-01-01

    The evolution and functions of Australia's Copyright Agency Limited are described. The agency is a copyright collecting organization which collectively administers the rights of authors and publishers whose works are copied in education, and enters into blanket agreements with educational authorities outside the existing statutory license. Some…

  19. Occupational dose equivalent limits

    International Nuclear Information System (INIS)

    Goldfinch, E.P.

    1980-01-01

    This paper considers methods of limiting individual radiation risks by recognizing the variation of risk with age at exposure, taking into account both somatic and genetic risks and proposes a simple formula for controlling individual cumulative exposure and hence risk. (Author)

  20. The Limits of Accountability.

    Science.gov (United States)

    Bailey, Stephen K.

    This discussion, presented at the Regent's Trustees' Conference, February 1973, reviews the limits of accountability in higher education. Managerial efficiency is suggested to assist in eliminating educational and financial waste. This, however, is the secondary concept emphasized. The primary emphasis indicates the legitimacy of the claims that a…