Science.gov

Sample records for long-term elevated atmospheric

  1. Effects of long-term elevated atmospheric CO{sub 2} concentrations on Pinus ponderosa

    SciTech Connect

    Surano, K.A.; Kercher, J.R.

    1993-10-01

    This report details the results from an experiment of the effects of long-term elevated atmospheric CO{sub 2} concentrations on ponderosa pine (Pinus ponderosa Laws.) saplings and seedlings. The study began in 1983 as a pilot study designed to explore the feasibility of using open-top chambers for continuous multi-year exposures on sapling-sized trees and to examine possible CO{sub 2} responses so that future research could be adequately designed. however, following the first year of exposure, preliminary results from the study indicated that measurements of CO{sub 2} responses should be intensified. Open-top chambers proved suitable for use in multiyear exposures of mature trees. With respect to the preliminary examination of CO{sub 2} responses, many interesting observations were made. The nature of the preliminary results suggests that future long-term field CO{sub 2} exposures on perennial species may be critical to the understanding and preparation for future environments. Other research reported here attempted to adapt an existing western coniferous forest growth and succession model for use in elevated CO{sub 2} scenarios using differential species responses, and assessed the usefulness of the model in that regard. Seven papers have been processed separately for inclusion in the appropriate data bases.

  2. Long-Term Response of High-Elevation Lakes to Changes in Atmospheric Deposition and Air Temperature

    NASA Astrophysics Data System (ADS)

    Mast, M.; Turk, J. T.; Campbell, D. H.; Clow, D. W.; Ingersoll, G. P.

    2008-12-01

    High-elevation lakes are often sensitive indicators of environmental and climate change. Here we evaluate over two decades of water-quality data from a long-term monitoring network of remote high-mountain lakes in three Colorado wilderness areas. In two of the areas, lake sulfate concentrations have decreased by a factor of 2-3 times since the mid-1980s, which is consistent with declines in precipitation sulfate measured at 11 high-elevation NADP stations in Colorado. The downward trends in lake and precipitation chemistry are likely the result of regional declines in sulfate emissions from power plants and nonferrous metal smelters. By contrast, lake sulfate concentrations increased dramatically in the third wilderness area despite declines in atmospherically deposited sulfate. In lakes in these areas, sulfate is derived primarily from pyrite oxidation in contrast to the other wilderness areas where sulfate is dominated by atmospheric sources. It is hypothesized that the upward trend in sulfate reflects enhanced pyrite weathering caused by an increase in annual air temperature of about 2-degrees Celsius since the mid-1980's. These results indicate the water-quality response of remote lakes to improvements in air quality may be complicated by long-term changes in climate.

  3. Long Term Baseline Atmospheric Monitoring

    ERIC Educational Resources Information Center

    Goldman, Mark A.

    1975-01-01

    Describes a program designed to measure the normal concentrations of certain chemical and physical parameters of the atmosphere so that quantitative estimates can be made of local, regional, and global pollution. (GS)

  4. Transitory effects of elevated atmospheric CO₂ on fine root dynamics in an arid ecosystem do not increase long-term soil carbon input from fine root litter.

    PubMed

    Ferguson, Scot D; Nowak, Robert S

    2011-06-01

    Experimental increases in atmospheric CO₂ often increase root production over time, potentially increasing soil carbon (C) sequestration. Effects of elevated atmospheric CO₂ on fine root dynamics in a Mojave desert ecosystem were examined for the last 4.5 yr of a long-term (10-yr) free air CO₂ enrichment (FACE) study at the Nevada desert FACE facility (NDFF). Sets of minirhizotron tubes were installed at the beginning of the NDFF experiment to characterize rooting dynamics of the dominant shrub Larrea tridentata, the codominant shrub Ambrosia dumosa and the plant community as a whole. Although significant treatment effects occurred sporadically for some fine root measurements, differences were transitory and often in opposite directions during other time-periods. Nonetheless, earlier root growth under elevated CO₂ helped sustain increased assimilation and shoot growth. Overall CO₂ treatment effects on fine root standing crop, production, loss, turnover, persistence and depth distribution were not significant for all sampling locations. These results were similar to those that occurred near the beginning of the NDFF experiment but unlike those in other ecosystems. Thus, increased C input into soils is unlikely to occur from fine root litter under elevated atmospheric CO₂ in this arid ecosystem. PMID:21355868

  5. Using an optimality model to understand medium and long-term responses of vegetation water use to elevated atmospheric CO2 concentrations

    PubMed Central

    Schymanski, Stanislaus J.; Roderick, Michael L.; Sivapalan, Murugesu

    2015-01-01

    Vegetation has different adjustable properties for adaptation to its environment. Examples include stomatal conductance at short time scale (minutes), leaf area index and fine root distributions at longer time scales (days–months) and species composition and dominant growth forms at very long time scales (years–decades–centuries). As a result, the overall response of evapotranspiration to changes in environmental forcing may also change at different time scales. The vegetation optimality model simulates optimal adaptation to environmental conditions, based on the assumption that different vegetation properties are optimized to maximize the long-term net carbon profit, allowing for separation of different scales of adaptation, without the need for parametrization with observed responses. This paper discusses model simulations of vegetation responses to today's elevated atmospheric CO2 concentrations (eCO2) at different temporal scales and puts them in context with experimental evidence from free-air CO2 enrichment (FACE) experiments. Without any model tuning or calibration, the model reproduced general trends deduced from FACE experiments, but, contrary to the widespread expectation that eCO2 would generally decrease water use due to its leaf-scale effect on stomatal conductance, our results suggest that eCO2 may lead to unchanged or even increased vegetation water use in water-limited climates, accompanied by an increase in perennial vegetation cover. PMID:26019228

  6. Chemistry and long-term decomposition of roots from Douglas-fir grown at elevated atmospheric CO2 and warming conditions

    EPA Science Inventory

    Elevated atmospheric CO2 and warming may affect litter quality of plants and its subsequent decomposition in forested ecosystems. Little data are available to test this potential feedback on root tissues. In this study, we used the fine (diameter ≤ 2 mm) and small (2-10 mm) roo...

  7. Chemistry and Long-Term Decomposition of Roots of Douglas-Fir Grown under Elevated Atmospheric Carbon Dioxide and Warming Conditions

    EPA Science Inventory

    Elevated atmospheric CO2 concentrations and warming may affect the quality of litters of forest plants and their subsequent decomposition in ecosystems, thereby potentially affecting the global carbon cycle. However, few data on root tissues are available to test this feedback to...

  8. Soil respiration, root biomass, and root turnover following long-term exposure of northern forests to elevated atmospheric CO2 and tropospheric O3.

    PubMed

    Pregitzer, Kurt S; Burton, Andrew J; King, John S; Zak, Donald R

    2008-01-01

    The Rhinelander free-air CO(2) enrichment (FACE) experiment is designed to understand ecosystem response to elevated atmospheric carbon dioxide (+CO(2)) and elevated tropospheric ozone (+O(3)). The objectives of this study were: to understand how soil respiration responded to the experimental treatments; to determine whether fine-root biomass was correlated to rates of soil respiration; and to measure rates of fine-root turnover in aspen (Populus tremuloides) forests and determine whether root turnover might be driving patterns in soil respiration. Soil respiration was measured, root biomass was determined, and estimates of root production, mortality and biomass turnover were made. Soil respiration was greatest in the +CO(2) and +CO(2) +O(3) treatments across all three plant communities. Soil respiration was correlated with increases in fine-root biomass. In the aspen community, annual fine-root production and mortality (g m(-2)) were positively affected by +O(3). After 10 yr of exposure, +CO(2) +O(3)-induced increases in belowground carbon allocation suggest that the positive effects of elevated CO(2) on belowground net primary productivity (NPP) may not be offset by negative effects of O(3). For the aspen community, fine-root biomass is actually stimulated by +O(3), and especially +CO(2) +O(3). PMID:18643941

  9. Long-term memory of atmospheric aerosols over India

    NASA Astrophysics Data System (ADS)

    B, A.

    2014-12-01

    Long-term memory of atmospheric variables is a least understood facet in atmospheric science. The temporal and spatial distribution of atmospheric aerosols depends largely on the atmospheric parameters. Time series analysis using a stochastic model reveals that atmospheric aerosols over India exhibit a long-term memory. Our analysis confirms that by using Autoregressive Integrated Moving Average (ARIMA) model we can parsimoniously model the aerosol optical depth (AOD) over the Indian region with a reasonably good accuracy. This major advantage of this method is that by using past observations we were able to generate forecasts for next 3 years. The forecasts thus generate shows a good fit with the observations. This persistence is due to the presence of temporal dependence between successive observations.

  10. ATMOS: Long term atmospheric measurements for mission to planet Earth

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A long-term, space-based measurement program, together with continued balloon and aircraft-borne investigations, is essential to monitor the predicted effects in the atmosphere, to determine to what extent the concentration measurements agree with current models of stratospheric chemistry, and to determine the condition of the ozone layer. The Atmospheric Trace Molecule Spectroscopy (ATMOS) Experiment is currently making comprehensive, global measurements of Earth's atmosphere as part of the Atmospheric Laboratory for Applications and Science (ATLAS) program on the Space Shuttle. Part of NASA's Mission to Planet Earth, ATLAS is a continuing series of missions to study Earth and the Sun and provide a more fundamental understanding of the solar influences on Earth's atmosphere. The ATMOS program, instruments, and science results are presented.

  11. Long-Term Variability in a Coupled Atmosphere Biosphere Model.

    NASA Astrophysics Data System (ADS)

    Delire, Christine; Foley, Jonathan A.; Thompson, Starley

    2004-10-01

    A fully coupled atmosphere biosphere model, version 3 of the NCAR Community Climate Model (CCM3) and the Integrated Biosphere Simulator (IBIS), is used to illustrate how vegetation dynamics may be capable of producing long-term variability in the climate system, particularly through the hydrologic cycle and precipitation. Two simulations of the global climate are conducted with fixed climatological sea surface temperatures: one including vegetation as a dynamic boundary condition, and the other keeping vegetation cover fixed. A comparison of the precipitation power spectra over land from these two simulations shows that dynamic interactions between the atmosphere and vegetation enhance precipitation variability at time scales from a decade to a century, while damping variability at shorter time scales.In these simulations, the two-way coupling between the atmosphere and the dynamic vegetation cover introduces persistent precipitation anomalies in several ecological transition zones: between forest and grasslands in the North American midwest, in southern Africa, and at the southern limit of the tropical forest in the Amazon basin, and between savanna and desert in the Sahel, Australia, and portions of the Arabian Peninsula. These regions contribute most to the long-term variability of the atmosphere vegetation system.Slow changes in the vegetation cover, resulting from a “red noise” integration of high-frequency atmospheric variability, are responsible for generating this long-term variability. Lead and lag correlation between precipitation and vegetation leaf area index (LAI) shows that LAI influences precipitation in the following years, and vice versa. A mechanism involving changes in LAI resulting in albedo, roughness, and evapotranspiration changes is proposed.


  12. Elevated CO2 increases long-term N mineralization and plant N uptake in a semiarid grassland: Results from a five-year 15N tracer study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term primary production response to elevated CO2 depends on soil nitrogen (N) mineralization. Despite much effort, it is still uncertain how elevated CO2 affects long-term soil N dynamics. To examine the effect of doubling atmospheric CO2 concentration on N dynamics in a semiarid grassland ecos...

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

    PubMed

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

    2016-01-01

    Biogeochemical models that incorporate nitrogen (N) limitation indicate that N availability will control the magnitude of ecosystem carbon uptake in response to rising CO2 . Some models, however, suggest that elevated CO2 may promote ecosystem N accumulation, a feedback that in the long term could circumvent N limitation of the CO2 response while mitigating N pollution. We tested this prediction using a nine-year CO2 xN experiment in a tidal marsh. Although the effects of CO2 are similar between uplands and wetlands in many respects, this experiment offers a greater likelihood of detecting CO2 effects on N retention on a decadal timescale because tidal marshes have a relatively open N cycle and can accrue soil organic matter rapidly. To determine how elevated CO2 affects N dynamics, we assessed the three primary fates of N in a tidal marsh: (1) retention in plants and soil, (2) denitrification to the atmosphere, and (3) tidal export. We assessed changes in N pools and tracked the fate of a (15) N tracer added to each plot in 2006 to quantify the fraction of added N retained in vegetation and soil, and to estimate lateral N movement. Elevated CO2 alone did not increase plant N mass, soil N mass, or (15) N label retention. Unexpectedly, CO2 and N interacted such that the combined N+CO2 treatment increased ecosystem N accumulation despite the stimulation in N losses indicated by reduced (15) N label retention. These findings suggest that in N-limited ecosystems, elevated CO2 is unlikely to increase long-term N accumulation and circumvent progressive N limitation without additional N inputs, which may relieve plant-microbe competition and allow for increased plant N uptake. PMID:26577708

  14. Long-term climate forcing by atmospheric oxygen concentrations

    NASA Astrophysics Data System (ADS)

    Poulsen, Christopher J.; Tabor, Clay; White, Joseph D.

    2015-06-01

    The percentage of oxygen in Earth’s atmosphere varied between 10% and 35% throughout the Phanerozoic. These changes have been linked to the evolution, radiation, and size of animals but have not been considered to affect climate. We conducted simulations showing that modulation of the partial pressure of oxygen (pO2), as a result of its contribution to atmospheric mass and density, influences the optical depth of the atmosphere. Under low pO2 and a reduced-density atmosphere, shortwave scattering by air molecules and clouds is less frequent, leading to a substantial increase in surface shortwave forcing. Through feedbacks involving latent heat fluxes to the atmosphere and marine stratus clouds, surface shortwave forcing drives increases in atmospheric water vapor and global precipitation, enhances greenhouse forcing, and raises global surface temperature. Our results implicate pO2 as an important factor in climate forcing throughout geologic time.

  15. Long-term operation of CsLiB(6)O(10) at elevated crystal temperature.

    PubMed

    Yap, Y K; Inoue, T; Sakai, H; Kagebayashi, Y; Mori, Y; Sasaki, T; Deki, K; Horiguchi, M

    1998-01-01

    We have successfully resolved the degradation problem of CsLiB(6)O(10) (CLBO) by means of elevated crystal temperature. CLBO crystals were continuously operated at 160 degrees C in ordinary room humidity. No degradation of performance was observed after more than 1 month. We believe that heating CLBO crystal above 130 degrees C can relieve stresses introduced by crystal hydration, cutting, polishing, and thermal shock owing to laser power absorption. Thus long-term operation of CLBO crystal is achieved for effective application of laser frequency conversion. Output stability from CLBO is also further enhanced at elevated crystal temperature. PMID:18084403

  16. The Atmospheric Radionuclide Transport Model (ARTM) - Validation of a long-term atmospheric dispersion model

    NASA Astrophysics Data System (ADS)

    Hettrich, Sebastian; Wildermuth, Hans; Strobl, Christopher; Wenig, Mark

    2016-04-01

    In the last couple of years, the Atmospheric Radionuclide Transport Model (ARTM) has been developed by the German Federal Office for Radiation Protection (BfS) and the Society for Plant and Reactor Security (GRS). ARTM is an atmospheric dispersion model for continuous long-term releases of radionuclides into the atmosphere, based on the Lagrangian particle model. This model, developed in the first place as a more realistic replacement for the out-dated Gaussian plume models, is currently being optimised for further scientific purposes to study atmospheric dispersion in short-range scenarios. It includes a diagnostic wind field model, allows for the application of building structures and multiple sources (including linear, 2-and 3-dimensional source geometries), and considers orography and surface roughness. As an output it calculates the activity concentration, dry and wet deposition and can model also the radioactive decay of Rn-222. As such, ARTM requires to undergo an intense validation process. While for short-term and short-range models, which were mainly developed for examining nuclear accidents or explosions, a few measurement data-sets are available for validation, data-sets for validating long-term models are very sparse and the existing ones mostly prove to be not applicable for validation. Here we present a strategy for the validation of long-term Lagrangian particle models based on the work with ARTM. In our validation study, the first part we present is a comprehensive analysis of the model sensitivities on different parameters like e.g. (simulation grid size resolution, starting random number, amount of simulation particles, etc.). This study provides a good estimation for the uncertainties of the simulation results and consequently can be used to generate model outputs comparable to the available measurements data at various distances from the emission source. This comparison between measurement data from selected scenarios and simulation results

  17. The effects on photosynthetic CO{sub 2} assimilation to long-term elevation of atmospheric CO{sub 2} concentration: An assessment of the response of Trifolium Repens L. cv. Blanca grown at F.A.C.E.

    SciTech Connect

    Lewis, C.E.

    1994-11-01

    Understanding how photosynthetic capacity acclimates to elevated CO{sub 2} concentrations is vital in predicting the response of important grassland species such as Trifolium repens. Previous studies of acclimatization have been carried out in artificial experimental conditions, such as acrylic greenhouses or controlled environment chambers. The advent of FACE technology has enabled a large area of crop to be fumigated in the field, providing more realistic growing conditions. Pure stands of Trifolium repens L. cv. Blanca grown at either 355 or 600{mu}mol mol{sup -1} CO{sub 2} were examined, and their photosynthetic response to elevated Ca determined via gas exchange studies. Rates of photosynthesis of young, fully expanded leaves were increased between 21 and 36% when grown and measured at elevated CO{sub 2}. This increase in A corresponded to a decrease in g{sub S} of between 18 and 52%. No acclimation effect was observed in the most frequently cut stands, whilst the response of stands clipped only 4 times per year was more variable. When down regulation of V{sub cmax} did occur, this was not nearly as marked as that which occurred in 3 other temperate species (Chrysanthemum leucanthemum, Ranunculus friesianus, Plantago lanceolata (L.) J. & C. Presl.), at similar growth regimes. No acclimation of stomatal frequency, SI or pore length was found to occur in the enriched clover stands.

  18. Wood properties of Populus and Betula in long-term exposure to elevated CO₂ and O₃.

    PubMed

    Kostiainen, Katri; Saranpää, Pekka; Lundqvist, Sven-Olof; Kubiske, Mark E; Vapaavuori, Elina

    2014-06-01

    We studied the interactive effects of elevated concentrations of CO2 and O3 on radial growth and wood properties of four trembling aspen (Populus tremuloides Michx.) clones and paper birch (Betula papyrifera Marsh.) saplings. The material for the study was collected from the Aspen FACE (free-air CO2 enrichment) experiment in Rhinelander (WI, USA). Trees had been exposed to four treatments [control, elevated CO2 (560 ppm), elevated O3 (1.5 times ambient) and combined CO2 + O3 ] during growing seasons 1998-2008. Most treatment responses were observed in the early phase of experiment. Our results show that the CO2- and O3-exposed aspen trees displayed a differential balance between efficiency and safety of water transport. Under elevated CO2, radial growth was enhanced and the trees had fewer but hydraulically more efficient larger diameter vessels. In contrast, elevated O3 decreased radial growth and the diameters of vessels and fibres. Clone-specific decrease in wood density and cell wall thickness was observed under elevated CO2 . In birch, the treatments had no major impacts on wood anatomy or wood density. Our study indicates that short-term impact studies conducted with young seedlings may not give a realistic view of long-term ecosystem responses. PMID:24372544

  19. Long-term antithrombotic pharmacotherapy following ST-elevation myocardial infarction.

    PubMed

    Buccheri, Sergio; Capodanno, Davide

    2016-06-01

    The selection and optimal duration of pharmacological agents to counteract thrombotic processes activated in patients with ST-elevation myocardial infarction (STEMI) still remain a debated issue in current clinical practice. Recently published trials have highlighted the potential benefits of dual-antiplatelet therapy (DAPT) extended beyond the currently recommended 12-months term. Anticoagulation with non-vitamin K oral anticoagulants in addition to DAPT has also been explored. Importantly, benefits of prolonged antithrombotic management strategies could be offset by harms following bleeding complications, therefore careful assessment of a patient benefit-risk profile must be used to drive individualized medical decisions. Appraising current available evidence is useful to inform clinical practice and to optimize the pharmacological management of patients with STEMI. Accordingly, we provide an overview of the literature focusing on long-term antithrombotic management strategies in patients with a recent or prior myocardial infarction, with a primary focus on STEMI. PMID:26934659

  20. Long term monitoring system integrated in an elevational gradient in NW Argentina

    NASA Astrophysics Data System (ADS)

    Carilla, J.; Malizia, A.; Osinaga, O.; Blundo, C.; Grau, R.; Malizia, L.; Aráoz, E.

    2013-05-01

    Ecological trends and ranges of variability are poorly known in the tropical and subtropical Andes. Long term studies are powerful tools to detect the response of vegetation dynamics, biodiversity and hydrological cycle to these trends. We present a long term monitoring system in NW Argentinean mountains, including forest permanent plots at different elevations and high elevation grasslands, encompassing more than 3.000 m elevation range. Long term studies include: 1) 66 ha of mountain forest permanent plots along the Yungas elevational gradient from c. 400 to 2500 masl , and latitudinal gradient (22-28S) with 45 plots in mature forests and 28 in secondary forests originated in grazing, agriculture and selective logging. Some of these permanent plots have achieved 20 years of monitoring and all of them are included in the "Red de Bosques Andinos" a network created recently, together with c. 10 institutions and more than 130 (c. 120 ha) forest permanent plots from Argentina to Colombia Andes. 2) Two GLORIA (Global Observation Research Initiative in Alpine Environments) sites, above 4000 masl with more than 170 species recorded, including one re-measurement. This system is included in GLORIA network (www.gloria.ac.at) and in GLORIA Andes (http://www.condesan.org/gloria), and 3) more than 15 satellite monitored high Andean lakes and a wide extension of vegas (75800 ha in Argentinean puna). A digital database is being implemented to organize and provide access to the information generated by these three systems coordinated by the Instituto de Ecología Regional (http://www.iecologia.com.ar). These monitoring data are analyzed together with instrumental and dendrochronological data to describe the dynamics of these ecosystems over an area of 20 million hectares distributed between 22 and 28°S. Some of the most significant results to date include: 1) secondary mountain forests are expanding over grasslands and agriculture lands, and tend to converge toward mature forest

  1. Long-term surface elevation changes in German North Sea salt marshes

    NASA Astrophysics Data System (ADS)

    Suchrow, Sigrid; Pohlmann, Nina; Stock, Martin; Jensen, Kai

    2012-02-01

    We analyzed long-term (19-21 years) surface elevation changes of salt marshes along the German mainland North Sea coast in a large and consistent data set (423 plots). Our aim was to determine the influence of 12 predictor variables, e.g. elevation, micro-topography and management data. For each plot, we measured elevation above sea level, once 1988-1990 and again 2009. The calculated surface elevation change per year (target variable SEC) was +0.6 cm yr -1 on average. 85.8% of the plots showed positive SEC values. Although 11 predictors were significantly correlated to SEC, only five driving on different scales were included by the tree fitting algorithm when using regression tree analysis. The resulting tree model with 11 terminal nodes explained 45.7% proportion of the variance in SEC values. Plots tended to high SEC values when a) lying low in relation to mean high tide, b) being located in the northern regions of the study area, and c) lying in drainage ditches. d) Grazing management did account for SEC variance only in northern regions. e) SEC was enhanced on non-grazed plots lying high in relation to mean high tide. We concluded that most of the studied salt marshes may outpace a predicted sea-level rise of about 0.1-0.2 cm yr -1, but barely half of the marsh areas might follow a sea-level rise of 0.6 cm yr -1. Regression tree analysis is a useful approach for studying changes in elevation of salt marshes when considering various variables.

  2. Long-term effects of elevated carbon dioxide on sour orange tree specific gravity and anatomy.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exposure to elevated levels of atmospheric CO2 for a period of 17 years resulted in small but statistically significant increases in wood basic specific gravity and number of rays per mm. Other anatomical characteristics (percentages of tissues, number of vessels per square mm, vessel diameters, and...

  3. Species and tissue type regulate long-term decomposition of brackish marsh plants grown under elevated CO2 conditions

    NASA Astrophysics Data System (ADS)

    Jones, Joshua A.; Cherry, Julia A.; McKee, Karen L.

    2016-02-01

    Organic matter accumulation, the net effect of plant production and decomposition, contributes to vertical soil accretion in coastal wetlands, thereby playing a key role in whether they keep pace with sea-level rise. Any factor that affects decomposition may affect wetland accretion, including atmospheric CO2 concentrations. Higher CO2 can influence decomposition rates by altering plant tissue chemistry or by causing shifts in plant species composition or biomass partitioning. A combined greenhouse-field experiment examined how elevated CO2 affected plant tissue chemistry and subsequent decomposition of above- and belowground tissues of two common brackish marsh species, Schoenoplectus americanus (C3) and Spartina patens (C4). Both species were grown in monoculture and in mixture under ambient (350-385 μL L-1) or elevated (ambient + 300 μL L-1) atmospheric CO2 conditions, with all other growth conditions held constant, for one growing season. Above- and belowground tissues produced under these treatments were decomposed under ambient field conditions in a brackish marsh in the Mississippi River Delta, USA. Elevated CO2 significantly reduced nitrogen content of S. americanus, but not sufficiently to affect subsequent decomposition. Instead, long-term decomposition (percent mass remaining after 280 d) was controlled by species composition and tissue type. Shoots of S. patens had more mass remaining (41 ± 2%) than those of S. americanus (12 ± 2%). Belowground material decomposed more slowly than that placed aboveground (62 ± 1% vs. 23 ± 3% mass remaining), but rates belowground did not differ between species. Increases in atmospheric CO2 concentration will likely have a greater effect on overall decomposition in this brackish marsh community through shifts in species dominance or biomass allocation than through effects on tissue chemistry. Consequent changes in organic matter accumulation may alter marsh capacity to accommodate sea-level rise through vertical

  4. Long-Term Response of Terrestrial Productivity to Elevated CO2 Remains a Grand Challenge in Terrestrial Biogeochemistry (Invited)

    NASA Astrophysics Data System (ADS)

    Finzi, A.

    2013-12-01

    There is large variability in the long-term response of terrestrial net primary production (NPP) to elevated concentrations of atmospheric CO2 (eCO2). In some ecosystems productivity remains higher under eCO2 compared to aCO2 at the decadal time scale. In other ecosystem productivity under eCO2 increases transiently, returning to levels observed at aCO2 in a few years or less. The diversity of ecosystem responses is as fascinating as it is difficult to understand. A number of scientists, including this one, have postulated that soil water and nutrient supply constrain productivity responses and that in the absence of increases in soil resource uptake productivity must decline because there is little evidence for increases in resource use efficiency, with perhaps the exception of grassland water-use efficiency in some instances. This contention is challenged by the data as they are currently understood. As such there is no unifying explanation for the diversity of these responses and hence models cannot be reasonably expected to accurately predict the timing and magnitude of terrestrial-C sequestration over the next century. Research on the impacts of elevated CO2 has not yet answered a fundamentally important, policy-relevant question in global change science. In this talk I present an analysis of the NPP literature from long-term experiments at eCO2 published to date (>5 years duration) in an effort to stimulate a discussion of why productivity responses to eCO2 vary from ecosystem to ecosystem. Explaining variations in productivity response to eCO2 is a grand challenge in terrestrial biogeochemistry.

  5. Elevated fluoride levels and periostitis in pediatric hematopoietic stem cell transplant recipients receiving long-term voriconazole.

    PubMed

    Tarlock, Katherine; Johnson, Darren; Cornell, Cathy; Parnell, Shawn; Meshinchi, Soheil; Baker, K Scott; Englund, Janet A

    2015-05-01

    Azole therapy is widely utilized in hematopoietic stem cell transplant (HCT) recipients for the treatment of aspergillus. Complications of voriconazole treatment related to its elevated fluoride content have been described in adults, including reports of symptomatic skeletal fluorosis. We review fluoride levels, clinical, and laboratory data in five pediatric HCT recipients on long-term voriconazole therapy, all found to have elevated serum fluoride levels. Two patients had toxic fluoride levels, one infant had symptoms of significant pain with movement and radiographs confirmed skeletal fluorosis. Monitoring fluoride levels in children, especially with skeletal symptoms, should be considered in patients on long-term voriconazole. PMID:25327935

  6. Long-Term Trends in Space-Ground Atmospheric Propagation Measurements

    NASA Technical Reports Server (NTRS)

    Zemba, Michael J.; Morse, Jacquelynne R.; Nessel, James A.

    2015-01-01

    Propagation measurement campaigns are critical to characterizing the atmospheric behavior of a location and efficiently designing space-ground links. However, as global climate change affects weather patterns, the long-term trends of propagation data may be impacted over periods of decades or longer. Particularly, at high microwave frequencies (10 GHz and above), rain plays a dominant role in the attenuation statistics, and it has been observed that rain events over the past 50 years have trended toward increased frequency, intensity, and rain height. In the interest of quantifying the impact of these phenomena on long-term trends in propagation data, this paper compares two 20 GHz measurement campaigns both conducted at NASA's White Sands facility in New Mexico. The first is from the Advanced Communication Technology Satellite (ACTS) propagation campaign from 1994 - 1998, while the second is amplitude data recorded during a site test interferometer (STI) phase characterization campaign from 2009 - 2014.

  7. Long-Term Trends in Space-Ground Atmospheric Propagation Measurements

    NASA Technical Reports Server (NTRS)

    Zemba, Michael J.; Nessel, James A.; Morse, Jacquelynne R.

    2015-01-01

    Propagation measurement campaigns are critical to characterizing the atmospheric behavior of a location and efficiently designing space-ground links. However, as global climate change affects weather patterns, the long-term trends of propagation data may be impacted over periods of decades or longer. Particularly, at high microwave frequencies (10 GHz and above), rain plays a dominant role in the attenuation statistics, and it has been observed that rain events over the past 50 years have trended toward increased frequency, intensity, and rain height. In the interest of quantifying the impact of these phenomena on long-term trends in propagation data, this paper compares two 20 GHz measurement campaigns both conducted at NASAs White Sands facility in New Mexico. The first is from the Advanced Communications Technology Satellite (ACTS) propagation campaign from 1994 to 1998, while the second is amplitude data recorded during a site test interferometer (STI) phase characterization campaign from 2009 to 2014.

  8. Fungal communities respond to long-term CO2 elevation by community reassembly.

    PubMed

    Tu, Qichao; Yuan, Mengting; He, Zhili; Deng, Ye; Xue, Kai; Wu, Liyou; Hobbie, Sarah E; Reich, Peter B; Zhou, Jizhong

    2015-04-01

    Fungal communities play a major role as decomposers in the Earth's ecosystems. Their community-level responses to elevated CO2 (eCO2), one of the major global change factors impacting ecosystems, are not well understood. Using 28S rRNA gene amplicon sequencing and co-occurrence ecological network approaches, we analyzed the response of soil fungal communities in the BioCON (biodiversity, CO2, and N deposition) experimental site in Minnesota, USA, in which a grassland ecosystem has been exposed to eCO2 for 12 years. Long-term eCO2 did not significantly change the overall fungal community structure and species richness, but significantly increased community evenness and diversity. The relative abundances of 119 operational taxonomic units (OTU; ∼27% of the total captured sequences) were changed significantly. Significantly changed OTU under eCO2 were associated with decreased overall relative abundance of Ascomycota, but increased relative abundance of Basidiomycota. Co-occurrence ecological network analysis indicated that eCO2 increased fungal community network complexity, as evidenced by higher intermodular and intramodular connectivity and shorter geodesic distance. In contrast, decreased connections for dominant fungal species were observed in the eCO2 network. Community reassembly of unrelated fungal species into highly connected dense modules was observed. Such changes in the co-occurrence network topology were significantly associated with altered soil and plant properties under eCO2, especially with increased plant biomass and NH4 (+) availability. This study provided novel insights into how eCO2 shapes soil fungal communities in grassland ecosystems. PMID:25616796

  9. Fungal Communities Respond to Long-Term CO2 Elevation by Community Reassembly

    PubMed Central

    Tu, Qichao; Yuan, Mengting; He, Zhili; Deng, Ye; Xue, Kai; Wu, Liyou; Hobbie, Sarah E.; Reich, Peter B.

    2015-01-01

    Fungal communities play a major role as decomposers in the Earth's ecosystems. Their community-level responses to elevated CO2 (eCO2), one of the major global change factors impacting ecosystems, are not well understood. Using 28S rRNA gene amplicon sequencing and co-occurrence ecological network approaches, we analyzed the response of soil fungal communities in the BioCON (biodiversity, CO2, and N deposition) experimental site in Minnesota, USA, in which a grassland ecosystem has been exposed to eCO2 for 12 years. Long-term eCO2 did not significantly change the overall fungal community structure and species richness, but significantly increased community evenness and diversity. The relative abundances of 119 operational taxonomic units (OTU; ∼27% of the total captured sequences) were changed significantly. Significantly changed OTU under eCO2 were associated with decreased overall relative abundance of Ascomycota, but increased relative abundance of Basidiomycota. Co-occurrence ecological network analysis indicated that eCO2 increased fungal community network complexity, as evidenced by higher intermodular and intramodular connectivity and shorter geodesic distance. In contrast, decreased connections for dominant fungal species were observed in the eCO2 network. Community reassembly of unrelated fungal species into highly connected dense modules was observed. Such changes in the co-occurrence network topology were significantly associated with altered soil and plant properties under eCO2, especially with increased plant biomass and NH4+ availability. This study provided novel insights into how eCO2 shapes soil fungal communities in grassland ecosystems. PMID:25616796

  10. Long-term orbit prediction for Tiangong-1 spacecraft using the mean atmosphere model

    NASA Astrophysics Data System (ADS)

    Tang, Jingshi; Liu, Lin; Cheng, Haowen; Hu, Songjie; Duan, Jianfeng

    2015-03-01

    China is planning to complete its first space station by 2020. For the long-term management and maintenance, the orbit of the space station needs to be predicted for a long period of time. Since the space station is expected to work in a low-Earth orbit, the error in the a priori atmosphere model contributes significantly to the rapid increase of the predicted orbit error. When the orbit is predicted for 20 days, the error in the a priori atmosphere model, if not properly corrected, could induce a semi-major axis error of up to a few kilometers and an overall position error of several thousand kilometers respectively. In this work, we use a mean atmosphere model averaged from NRLMSISE00. The a priori reference mean density can be corrected during the orbit determination. For the long-term orbit prediction, we use sufficiently long period of observations and obtain a series of the diurnal mean densities. This series contains the recent variation of the atmosphere density and can be analyzed for various periodic components. After being properly fitted, the mean density can be predicted and then applied in the orbit prediction. Here we carry out the test with China's Tiangong-1 spacecraft at the altitude of about 340 km and we show that this method is simple and flexible. The densities predicted with this approach can serve in the long-term orbit prediction. In several 20-day prediction tests, most predicted orbits show semi-major axis errors better than 700 m and overall position errors better than 400 km.

  11. Relativistic magnetospheric electrons: Lower ionospheric conductivity and long-term atmospheric variability

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Blake, J. B.; Klebesadel, R.; Sentman, D. D.; Gorney, D. J.; Higbie, P. R.

    1989-01-01

    Long term observations of relativistic electrons in the earth's outer magnetosphere show a strong solar cycle dependence with a prominent intensity maximum during the approach to solar minimum. This population therefore closely corresponds to the presence of high speed solar wind streams emanating from solar coronal holes. Using a numerical code, the precipitating electron energy deposition in the earth's upper and middle atmosphere were calculated. Observed events (typically persisting several days) would have maximum effect in the 40 to 60 km altitude range with peak energy depositions greater than 110 keV/cu cm-s. It is suggested that this electron population could play an important long term role in modulating lower D region ionization and middle atmospheric ozone chemistry. Methods are described of observing middle atmospheric and lower ionospheric effects of the electrons including balloon, riometer, and space-based ozone sensor systems. A particularly promising approach may involve the monitoring of global Schumann resonance modes which are sensitive to global changes in the properties of the earth-ionosphere cavity. Present work indicates that Schumann resonance properties are moderately correlated with the flux of precipitating relativistic electrons thus offering the possibility of continuously monitoring this aspect of magnetosphere-atmosphere coupling.

  12. Respiratory oxygen uptake is not decreased by an instantaneous elevation of [CO2], but is increased with long-term growth in the field at elevated [CO2].

    PubMed

    Davey, Phillip A; Hunt, Stephen; Hymus, Graham J; DeLucia, Evan H; Drake, Bert G; Karnosky, David F; Long, Stephen P

    2004-01-01

    Averaged across many previous investigations, doubling the CO2 concentration ([CO2]) has frequently been reported to cause an instantaneous reduction of leaf dark respiration measured as CO2 efflux. No known mechanism accounts for this effect, and four recent studies have shown that the measurement of respiratory CO2 efflux is prone to experimental artifacts that could account for the reported response. Here, these artifacts are avoided by use of a high-resolution dual channel oxygen analyzer within an open gas exchange system to measure respiratory O2 uptake in normal air. Leaf O2 uptake was determined in response to instantaneous elevation of [CO2] in nine contrasting species and to long-term elevation in seven species from four field experiments. Over six hundred separate measurements of respiration failed to reveal any decrease in respiratory O2 uptake with an instantaneous increase in [CO2]. Respiration was found insensitive not only to doubling [CO2], but also to a 5-fold increase and to decrease to zero. Using a wide range of species and conditions, we confirm earlier reports that inhibition of respiration by instantaneous elevation of [CO2] is likely an experimental artifact. Instead of the expected decrease in respiration per unit leaf area in response to long-term growth in the field at elevated [CO2], there was a significant increase of 11% and 7% on an area and mass basis, respectively, averaged across all experiments. The findings suggest that leaf dark respiration will increase not decrease as atmospheric [CO2] rises. PMID:14701915

  13. Can Long-Term Precipitation Trends Explain Net Annual Carbon Loss From High Elevation Alpine Tundra?

    NASA Astrophysics Data System (ADS)

    Knowles, J. F.; Blanken, P.; Williams, M. W.

    2013-12-01

    Five continuous years of eddy covariance measurements over predominantly snow-free alpine tundra on Niwot Ridge, Colorado show that ecosystem respiration dominates over gross primary productivity on an annual basis, and that this ecosystem is a significant source of carbon to the atmosphere over long periods of time. Long-term data also show that precipitation has increased since the 1960s, in contrast to modeled forecasts that generally predict decreasing precipitation through the 21st century across the Rocky Mountain region. To constrain the specific relationship between precipitation and the alpine tundra carbon cycle, we tested the degree to which precipitation and soil moisture determined respiration fluxes over the course of three years, and across a range of 17 sites, including xeric, mesic, and hydric alpine tundra soils, within the footprint of ongoing eddy covariance measurements. Overall, we found that respiration from this ecosystem was principally moisture-limited. Cumulatively, the highest respiration rates were measured from hydric soils associated with seasonal ice lenses and perched water tables, however, growing season respiration rates peaked in mesic areas when hydric soils were saturated. Respiration from xeric soils increased with soil moisture, but fluxes from these areas were small in magnitude relative to mesic and hydric soils. Changes in precipitation and resultant soil moisture thus invoked a bidirectional response from alpine tundra soils, as moisture and respiration were positively correlated in some areas, but negatively correlated in others, depending on landscape position and prevailing soil moisture regime. Interannually, however, respiration fluxes were highest in wet years, indicating that moisture stimulated respiration from xeric and mesic soils more than it was suppressed from hydric soils. In sum, increased precipitation over the last half-century may be augmenting respiratory fluxes from alpine tundra, but changes in

  14. Is Ecosystem-Atmosphere Observation in Long-Term Networks actually Science?

    NASA Astrophysics Data System (ADS)

    Schmid, H. P. E.

    2015-12-01

    Science uses observations to build knowledge by testable explanations and predictions. The "scientific method" requires controlled systematic observation to examine questions, hypotheses and predictions. Thus, enquiry along the scientific method responds to questions of the type "what if …?" In contrast, long-term observation programs follow a different strategy: we commonly take great care to minimize our influence on the environment of our measurements, with the aim to maximize their external validity. We observe what we think are key variables for ecosystem-atmosphere exchange and ask questions such as "what happens next?" or "how did this happen?" This apparent deviation from the scientific method begs the question whether any explanations we come up with for the phenomena we observe are actually contributing to testable knowledge, or whether their value remains purely anecdotal. Here, we present examples to argue that, under certain conditions, data from long-term observations and observation networks can have equivalent or even higher scientific validity than controlled experiments. Internal validity is particularly enhanced if observations are combined with modeling. Long-term observations of ecosystem-atmosphere fluxes identify trends and temporal scales of variability. Observation networks reveal spatial patterns and variations, and long-term observation networks combine both aspects. A necessary condition for such observations to gain validity beyond the anecdotal is the requirement that the data are comparable: a comparison of two measured values, separated in time or space, must inform us objectively whether (e.g.) one value is larger than the other. In turn, a necessary condition for the comparability of data is the compatibility of the sensors and procedures used to generate them. Compatibility ensures that we compare "apples to apples": that measurements conducted in identical conditions give the same values (within suitable uncertainty intervals

  15. Modelling the soil-atmosphere exchange of POPs: Long-term steady state and diurnal fluctuations

    NASA Astrophysics Data System (ADS)

    Bao, Z.; Beckingham, B.; Maier, U.; Haberer, C.; Grathwohl, P.

    2014-12-01

    Soil-atmosphere exchange is an important transport process influencing environmental fate and transport of many persistent organic pollutants (POPs). This study focuses on modelling the gaseous exchange of a semi-volatile polycyclic aromatic hydrocarbon (phenanthrene) between soil and the atmosphere using the multicomponent reactive transport code MIN3P. MIN3P is typically applied to simulate aqueous and vapor phase subsurface transport and reaction processes. We extended the code to also include an atmospheric boundary layer where eddy diffusion and photodegradation take place. The relevant processes and parameters affecting soil-atmosphere exchange were investigated in several scenarios and at various time scales. We found that phenanthrene is well-mixed in the atmospheric boundary layer under neutral or stable atmospheric conditions due to fast eddy diffusion. Uptake of airborne phenanthrene to soils is limited by the soil properties and initially depends on diffusion in soil gas and sorption to the solids. On the long term seepage water dominates transport into deeper soil layers; biodegradation finally leads to steady-state concentration profiles in the subsurface typically achieved after a few centuries. If concentrations in the atmosphere decrease, e.g. due to environmental legislation, then soils become sources for the POPs for the first two months and function as sinks again for the POPs until new steady state concentrations are reached (after decades to centuries). MIN3P was also used to simulate diurnal soil-atmosphere exchanges of airborne pollutants due to temperature changes and photodegradation, both which cause fluctuations in atmospheric concentrations and therefore affect mass transfer between soil and the atmosphere. The model can further be applied to estimate the environmental fate of other POPs between soil and the atmosphere under different environmental pollution and climate change scenarios.

  16. LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir Model

    NASA Astrophysics Data System (ADS)

    Zeebe, R. E.

    2011-06-01

    The LOSCAR model is designed to efficiently compute the partitioning of carbon between ocean, atmosphere, and sediments on time scales ranging from centuries to millions of years. While a variety of computationally inexpensive carbon cycle models are already available, many are missing a critical sediment component, which is indispensable for long-term integrations. One of LOSCAR's strengths is the coupling of ocean-atmosphere routines to a computationally efficient sediment module. This allows, for instance, adequate computation of CaCO3 dissolution, calcite compensation, and long-term carbon cycle fluxes, including weathering of carbonate and silicate rocks. The ocean component includes various biogeochemical tracers such as total carbon, alkalinity, phosphate, oxygen, and stable carbon isotopes. We have previously published applications of the model tackling future projections of ocean chemistry and weathering, pCO2 sensitivity to carbon cycle perturbations throughout the Cenozoic, and carbon/calcium cycling during the Paleocene-Eocene Thermal Maximum. The focus of the present contribution is the detailed description of the model including numerical architecture, processes and parameterizations, tuning, and examples of input and output. Typical CPU integration times of LOSCAR are of order seconds for several thousand model years on current standard desktop machines. The LOSCAR source code in C can be obtained from the author by sending a request to loscar.model@gmail.com.

  17. Long-term response of oceans to CO2 removal from the atmosphere

    NASA Astrophysics Data System (ADS)

    Mathesius, Sabine; Hofmann, Matthias; Caldeira, Ken; Schellnhuber, Hans Joachim

    2015-12-01

    Carbon dioxide removal (CDR) from the atmosphere has been proposed as a measure for mitigating global warming and ocean acidification. To assess the extent to which CDR might eliminate the long-term consequences of anthropogenic CO2 emissions in the marine environment, we simulate the effect of two massive CDR interventions with CO2 extraction rates of 5 GtC yr-1 and 25 GtC yr-1, respectively, while CO2 emissions follow the extended RCP8.5 pathway. We falsify two hypotheses: the first being that CDR can restore pre-industrial conditions in the ocean by reducing the atmospheric CO2 concentration back to its pre-industrial level, and the second being that high CO2 emissions rates (RCP8.5) followed by CDR have long-term oceanic consequences that are similar to those of low emissions rates (RCP2.6). Focusing on pH, temperature and dissolved oxygen, we find that even after several centuries of CDR deployment, past CO2 emissions would leave a substantial legacy in the marine environment.

  18. Species and tissue type regulate long-term decomposition of brackish marsh plants grown under elevated CO2 conditions

    USGS Publications Warehouse

    Jones, Joshua A; Cherry, Julia A; Mckee, Karen L.

    2016-01-01

    Organic matter accumulation, the net effect of plant production and decomposition, contributes to vertical soil accretion in coastal wetlands, thereby playing a key role in whether they keep pace with sea-level rise. Any factor that affects decomposition may affect wetland accretion, including atmospheric CO2 concentrations. Higher CO2 can influence decomposition rates by altering plant tissue chemistry or by causing shifts in plant species composition or biomass partitioning. A combined greenhouse-field experiment examined how elevated CO2 affected plant tissue chemistry and subsequent decomposition of above- and belowground tissues of two common brackish marsh species, Schoenoplectus americanus (C3) and Spartina patens (C4). Both species were grown in monoculture and in mixture under ambient (350-385 μL L-1) or elevated (ambient + 300 μL L-1) atmospheric CO2 conditions, with all other growth conditions held constant, for one growing season. Above- and belowground tissues produced under these treatments were decomposed under ambient field conditions in a brackish marsh in the Mississippi River Delta, USA. Elevated CO2 significantly reduced nitrogen content of S. americanus, but not sufficiently to affect subsequent decomposition. Instead, long-term decomposition (percent mass remaining after 280 d) was controlled by species composition and tissue type. Shoots of S. patens had more mass remaining (41 ± 2%) than those of S. americanus (12 ± 2 %). Belowground material decomposed more slowly than that placed aboveground (62 ± 1% vs. 23 ± 3% mass remaining), but rates belowground did not differ between species. Increases in atmospheric CO2concentration will likely have a greater effect on overall decomposition in this brackish marsh community through shifts in species dominance or biomass allocation than through effects on tissue chemistry. Consequent changes in organic matter accumulation may alter marsh capacity to accommodate sea-level rise

  19. Long-term soil water trends across a 1000 m elevation gradient

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a general consensus among climate models that the direct influence of increasing temperature on evaporative demand will result in drier soils, reduced water supply and more frequent drought conditions. The data available to evaluate long term soil water trends that may result from climate c...

  20. Impact of short-term and long-term elevated CO2 on emission of carbonyls from adult Quercus petraea and Carpinus betulus trees.

    PubMed

    Kreuzwieser, Jürgen; Rennenberg, Heinz; Steinbrecher, Rainer

    2006-07-01

    The study aimed to elucidate the effect of elevated CO2 in short- and long-term experiments on the emission potential of carbonyls from mature oak (Quercus petraea) and hornbeam (Carpinus betulus). The trees were investigated using a canopy crane established in a mixed forest in Switzerland. Short-term CO2 experiments were performed on single leaves with a gas exchange measuring unit by increasing CO2 in the enclosure before and during the measurements. Long-term CO2 fumigation was performed for one vegetation period by a webFACE design. Short-term as well as long-term exposure of leaves resulted in no significant changes in carbonyl exchange in neither Q. petraea nor C. betulus. Carbonyl emission was not affected by stomatal closure under elevated CO2 levels. In contrast to the emission of isoprenoids from vegetation which is thought to be reduced at elevated atmospheric CO2, the exchange of carbonyls seems to be generally unaffected under these conditions. PMID:16314012

  1. Study of archaeological artefacts to refine the model of iron long-term indoor atmospheric corrosion

    NASA Astrophysics Data System (ADS)

    Monnier, J.; Legrand, L.; Bellot-Gurlet, L.; Foy, E.; Reguer, S.; Rocca, E.; Dillmann, P.; Neff, D.; Mirambet, F.; Perrin, S.; Guillot, I.

    2008-09-01

    The study of long-term indoor atmospheric corrosion is involved in the field of the interim storage of nuclear wastes. Indeed study of archaeological artefacts is one of the only mean to gather information on very long periods. Concerning ancient items, due to the complexity of the system, it is necessary to couple many analytical techniques from the macro to the microscopic scale. This enables to propose a description of the Amiens cathedral chain rust layers, made of a matrix of goethite, with lepidocrocite and akaganeite locally present and marbling of a poor crystallized phase associated to ferrihydrite. Electrochemical measurements permit to study the reduction capacity of the rust layer and to draw reduction mechanisms of the so-called active phases, by in situ experiments coupled with X-ray diffraction and X-ray absorption spectroscopy.

  2. Long-term variability of oceanic frontal zones associated with large-scale atmospheric forcing

    NASA Astrophysics Data System (ADS)

    Kazmin, A. S.

    2016-03-01

    Global satellite sea surface temperature (SST) measurements and NCEP/NCAR reanalysis wind data for the period of 1982-2009 have been used to study the relationship between long-term variability of oceanic frontal zones (OFZ) and large-scale atmospheric forcing. Statistically significant positive correlations between the maximum magnitude of the meridional gradient of zonally averaged SST and meridional shear of zonal wind (which is an estimate of the Ekman convergence intensity) were found for all subpolar and subtropical OFZ of the World Ocean. Variability of the latitudinal position of OFZ cores may be associated with Ekman advection variability due to zonal wind variations. Strengthening of zonal wind results in a shift of subpolar OFZ cores to the south/north in the Northern/Southern hemispheres.

  3. Long-Term Atmospheric Corrosion of Aluminum Alloy 2024-T4 in a Coastal Environment

    NASA Astrophysics Data System (ADS)

    Zhang, Teng; He, Yuting; Cui, Ronghong; An, Tao

    2015-07-01

    Aluminum alloy 2024-T4 specimens were exposed to atmosphere for 7, 12, and 20 years, respectively, to study long-term corrosion in a coastal environment. One-directional corrosion region and cross-directional corrosion region were defined according to corrosion characters. The statistical regularities, surface appearance, corrosion products, and cross-sectional morphology of both regions were investigated. It was found that the minimum remaining thicknesses of each region can be described by a normal distribution and linearly decrease as the exposure time is increased from 7 to 20 years. The corrosion pits, chlorine ions, and interlinked inner pits are promoting exfoliation, and the alloy's corrosion susceptibility along the long transverse direction is strongly location dependent due to the restrictions imposed by the side material.

  4. Long-term Outcomes of Drug-eluting versus Bare-metal stent for ST-elevation Myocardial Infarction

    PubMed Central

    Wang, Liping; Wang, Hongyun; Dong, Pingshuan; Li, Zhuanzhen; Wang, Yanyu; Duan, Nana; Zhao, Yuwei; Wang, Shaoxin

    2014-01-01

    Background Long-term outcomes of drug-eluting stents (DES) versus bare-metal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI) remain uncertain. Objective To investigate long-term outcomes of drug-eluting stents (DES) versus bare-metal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI). Methods We performed search of MEDLINE, EMBASE, the Cochrane library, and ISI Web of Science (until February 2013) for randomized trials comparing more than 12-month efficacy or safety of DES with BMS in patients with STEMI. Pooled estimate was presented with risk ratio (RR) and its 95% confidence interval (CI) using random-effects model. Results Ten trials with 7,592 participants with STEMI were included. The overall results showed that there was no significant difference in the incidence of all-cause death and definite/probable stent thrombosis between DES and BMS at long-term follow-up. Patients receiving DES implantation appeared to have a lower 1-year incidence of recurrent myocardial infarction than those receiving BMS (RR = 0.75, 95% CI 0.56 to 1.00, p= 0.05). Moreover, the risk of target vessel revascularization (TVR) after receiving DES was consistently lowered during long-term observation (all p< 0.01). In subgroup analysis, the use of everolimus-eluting stents (EES) was associated with reduced risk of stent thrombosis in STEMI patients (RR = 0.37, p=0.02). Conclusions DES did not increase the risk of stent thrombosis in patients with STEMI compared with BMS. Moreover, the use of DES did lower long-term risk of repeat revascularization and might decrease the occurrence of reinfarction. PMID:25004414

  5. The Long-term Middle Atmospheric Influence of Very Large Solar Proton Events

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Marsh, Daniel R.; Vitt, Francis M.; Garcia, Rolando R.; Randall, Cora E.; Fleming, Eric L.; Frith, Stacey M.

    2008-01-01

    Long-term variations in ozone have been caused by both natural and humankind related processes. The humankind or anthropogenic influence on ozone originates from the chlorofluorocarbons and halons (chlorine and bromine) and has led to international regulations greatly limiting the release of these substances. Certain natural ozone influences are also important in polar regions and are caused by the impact of solar charged particles on the atmosphere. Such natural variations have been studied in order to better quantify the human influence on polar ozone. Large-scale explosions on the Sun near solar maximum lead to emissions of charged particles (mainly protons and electrons), some of which enter the Earth's magnetosphere and rain down on the polar regions. "Solar proton events" have been used to describe these phenomena since the protons associated with these solar events sometimes create a significant atmospheric disturbance. We have used the National Center for Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM) to study the long-term (> few months) influences of solar proton events from 1963 through 2004 on stratospheric ozone and temperature. There were extremely large solar proton events in 1972, 1989,2000,2001, and 2003. These events caused very distinctive polar changes in layers of the Earth's atmosphere known as the stratosphere (12-50 km; -7-30 miles) and mesosphere (50-90 km; 30-55 miles). The solar protons connected with these events created hydrogen- and nitrogen-containing compounds, which led to the polar ozone destruction. The nitrogen-containing compounds, called odd nitrogen, lasted much longer than the hydrogen-containing compounds and led to long-lived stratospheric impacts. An extremely active period for these events occurred in the five-year period, 2000- 2004, and caused increases in odd nitrogen which lasted for several months after individual events. Associated stratospheric ozone decreases of >lo% were calculated

  6. Maintenance of C sinks sustains enhanced C assimilation during long-term exposure to elevated [CO2] in Mojave Desert shrubs.

    PubMed

    Aranjuelo, Iker; Ebbets, Allison L; Evans, R Dave; Tissue, David T; Nogués, Salvador; van Gestel, Natasja; Payton, Paxton; Ebbert, Volker; Adams, Williams W; Nowak, Robert S; Smith, Stanley D

    2011-10-01

    During the first few years of elevated atmospheric [CO(2)] treatment at the Nevada Desert FACE Facility, photosynthetic downregulation was observed in desert shrubs grown under elevated [CO(2)], especially under relatively wet environmental conditions. Nonetheless, those plants maintained increased A (sat) (photosynthetic performance at saturating light and treatment [CO(2)]) under wet conditions, but to a much lesser extent under dry conditions. To determine if plants continued to downregulate during long-term exposure to elevated [CO(2)], responses of photosynthesis to elevated [CO(2)] were examined in two dominant Mojave Desert shrubs, the evergreen Larrea tridentata and the drought-deciduous Ambrosia dumosa, during the eighth full growing season of elevated [CO(2)] treatment at the NDFF. A comprehensive suite of physiological processes were collected. Furthermore, we used C labeling of air to assess carbon allocation and partitioning as measures of C sink activity. Results show that elevated [CO(2)] enhanced photosynthetic performance and plant water status in Larrea, especially during periods of environmental stress, but not in Ambrosia. δ(13)C analyses indicate that Larrea under elevated [CO(2)] allocated a greater proportion of newly assimilated C to C sinks than Ambrosia. Maintenance by Larrea of C sinks during the dry season partially explained the reduced [CO(2)] effect on leaf carbohydrate content during summer, which in turn lessened carbohydrate build-up and feedback inhibition of photosynthesis. δ(13)C results also showed that in a year when plant growth reached the highest rates in 5 years, 4% (Larrea) and 7% (Ambrosia) of C in newly emerging organs were remobilized from C that was assimilated and stored for at least 2 years prior to the current study. Thus, after 8 years of continuous exposure to elevated [CO(2)], both desert perennials maintained their photosynthetic capacities under elevated [CO(2)]. We conclude that C storage, remobilization

  7. Assessing long-term impacts of increased crop productivity on atmospheric CO2.

    PubMed

    Cavazzoni, J; Volk, T

    1996-05-01

    A full assessment of the impacts of land clearance and crop production on atmospheric CO2 requires a systems approach. By considering long-term soil carbon changes and fossil fuel energy inputs, we show that increased crop productivity will alleviate CO2 release to the atmosphere primarily by preventing additional land cultivation. Each hectare of cropland undergoing a simulated threefold crop productivity increase here prevents a net release on the order of 150-200 Mg C to the atmosphere over 100 years by avoiding additional land cultivation which would otherwise be required. This effective carbon sink would slowly diminish with time due to fossil fuel energy input requirements. However, future self-containment of the energy needs of high-yield crop production may displace on the order of 1.0 Pg C per year of fossil fuel carbon, in addition to the carbon sink attributable to avoided land cultivation. By avoiding land cultivation, high yield crop systems also preserve natural ecosystems. PMID:11539330

  8. Effects of long-term low atmospheric pressure on gas exchange and growth of lettuce

    NASA Astrophysics Data System (ADS)

    Tang, Yongkang; Guo, Shuangsheng; Dong, Wenping; Qin, Lifeng; Ai, Weidang; Lin, Shan

    2010-09-01

    The objectives of this research were to determine photosynthesis, evapotranspiration and growth of lettuce at long-term low atmospheric pressure. Lettuce ( Lactuca sativa L . cv. Youmaicai) plants were grown at 40 kPa total pressure (8.4 kPa p) or 101 kPa total pressure (20.9 kPa p) from seed to harvest for 35 days. Germination rate of lettuce seeds decreased by 7.6% at low pressure, although this was not significant. There was no significant difference in crop photosynthetic rate between hypobaria and ambient pressure during the 35-day study. The crop evapotranspiration rate was significantly lower at low pressure than that at ambient pressure from 20 to 30 days after planting (DAP), but it had no significant difference before 20 DAP or after 30 DAP. The growth cycle of lettuce plants at low pressure was delayed. At low pressure, lettuce leaves were curly at the seedling stage and this disappeared gradually as the plants grew. Ambient lettuce plants were yellow and had an epinastic growth at harvest. The shoot height, leaf number, leaf length and shoot/root ratio were lower at low pressure than those at ambient pressure, while leaf area and root growth increased. Total biomass of lettuce plants grown at two pressures had no significant difference. Ethylene production at low pressure decreased significantly by 38.8% compared with ambient pressure. There was no significant difference in microelements, nutritional phytochemicals and nitrate concentrations at the two treatments. This research shows that lettuce can be grown at long-term low pressure (40 kPa) without significant adverse effects on seed germination, gas exchange and plant growth. Furthermore, ethylene release was reduced in hypobaria.

  9. A Long-term Perspective on Recent Increases in Atmospheric Methane Abundance (Invited)

    NASA Astrophysics Data System (ADS)

    Dlugokencky, E. J.; Lang, P.; Masarie, K.; Crotwell, A. M.; Bruhwiler, L.

    2010-12-01

    After CO2, methane (CH4) is the most important greenhouse gas influenced by human activities. Its chemistry results in additional indirect climate effects from production of tropospheric O3, which also affects air quality, and stratospheric H2O. Natural emissions of CH4 from Arctic permafrost and hydrates are susceptible to changing climate. These sources recently received attention in the media because of their potential to cause strong positive climate feedbacks. But how much of this attention is warranted? From 1999 through 2006, the global burden of atmospheric CH4 remained nearly constant. During 2007 and 2008, globally averaged CH4 increased by ~13 ppb. Do these increases signal the start of increased emissions in the Arctic from permafrost or hydrates because of warming climate? We found that the likely drivers of these increases are greater than average wetland CH4 emissions at high northern latitudes during 2007 because of exceptionally warm temperatures and in the tropics during 2007 and 2008 because of greater than normal precipitation in wetland regions during a La Niña. These increases result from interannual variations in temperature and precipitation (i.e., weather), which may be in part the result of long-term climate change, but there is yet no evidence for large permanent increases in CH4 emissions. For 2009, our preliminary estimate of the global increase is ~5 ppb. When evaluating these recent changes in atmospheric CH4 burden, it is useful to consider the long-term behavior of CH4. We previously showed that, if OH concentrations had been constant over the period of our observations, then total global CH4 emissions had been constant. The observed decrease in CH4 growth rate is consistent with a system approaching steady state, where the time constant of that approach is the CH4 atmospheric lifetime (τ). Is this model of long-term behavior still consistent with the data today? The approach to steady state for this system, with zeroth

  10. Long-term prognostic significance of admission plateletcrit values in patients with non-ST elevation myocardial infarction.

    PubMed

    Gul, Mehmet; Uyarel, Huseyin; Akgul, Ozgur; Akkaya, Emre; Surgit, Ozgur; Cakmak, Huseyin Altug; Pusuroglu, Hamdi; Yakisan, Turab; Aslan, Serkan; Eksik, Abdurrahman

    2016-09-01

    The plateletcrit has been investigated as a new predictor of cardiovascular risk. The objective of our study was to investigate the role of admission plateletcrit in predicting long-term cardiovascular mortality in patients presenting with non-ST-segment elevation myocardial infarction (NSTEMI). We enrolled 296 patients with NSTEMI (mean age 59.2 ± 11.8 years; 228 men, 68 women) in this study. The study population was divided into tertiles on the basis of admission plateletcrit values. A high plateletcrit (n = 98) was defined as a value in the upper third tertile (plateletcrit >0.23), and a low plateletcrit (n = 198) was defined as any value in the lower two tertiles (plateletcrit ≤0.23). The median follow-up time was 38 months. In multivariate analyses, a significant association was noted between high plateletcrit values and the adjusted risk of long-term mortality (odds ratio = 12.15, 95% confidence interval = 1.78-82.77; P < 0.001). In the Kaplan-Meier survival analysis, the long-term mortality rate was 20.4% in the high plateletcrit group versus 4.5% in the low plateletcrit group (P < 0.001). Long-term major advanced cardiac events (MACE), hospitalization for heart failure and reinfarction were significantly higher in patients with high plateletcrit. Admission plateletcrit is a strong and independent predictor of long-term cardiovascular mortality in patients with NSTEMI. PMID:26820228

  11. Long-term Internal Variability of the Tropical Pacific Atmosphere-Ocean System

    NASA Astrophysics Data System (ADS)

    Hadi Bordbar, Mohammad; Martin, Thomas; Park, Wonsun; Latif, Mojib

    2016-04-01

    The tropical Pacific has featured some remarkable trends during the recent decades such as an unprecedented strengthening of the Trade Winds, a strong cooling of sea surface temperatures (SST) in the eastern and central part, thereby slowing global warming and strengthening the zonal SST gradient, and highly asymmetric sea level trends with an accelerated rise relative to the global average in the western and a drop in the eastern part. These trends have been linked to an anomalously strong Pacific Walker Circulation, the major zonal atmospheric overturning cell in the tropical Pacific sector, but the origin of the strengthening is controversial. Here we address the question as to whether the recent decadal trends in the tropical Pacific atmosphere-ocean system are within the range of internal variability, as simulated in long unforced integrations of global climate models. We show that the recent trends are still within the range of long-term internal decadal variability. Further, such variability strengthens in response to enhanced greenhouse gas concentrations, which may further hinder detection of anthropogenic climate signals in that region.

  12. Elevated Cardiac Troponin in Acute Stroke without Acute Coronary Syndrome Predicts Long-Term Adverse Cardiovascular Outcomes

    PubMed Central

    Bhatt, Reema; Bove, Alfred A.

    2014-01-01

    Background. Elevated cardiac troponin in acute stroke in absence of acute coronary syndrome (ACS) has unclear long-term outcomes. Methods. Retrospective analysis of 566 patients admitted to Temple University Hospital from 2008 to 2010 for acute stroke was performed. Patients were included if cardiac troponin I was measured and had no evidence of ACS and an echocardiogram was performed. Of 200 patients who met the criteria, baseline characteristics, electrocardiograms, and major adverse cardiovascular events (MACE) were reviewed. Patients were characterized into two groups with normal and elevated troponins. Primary end point was nonfatal myocardial infarction during follow-up period after discharge. The secondary end points were MACE and death from any cause. Results. For 200 patients, 17 patients had positive troponins. Baseline characteristics were as follows: age 63.1 ± 13.8, 64% African Americans, 78% with hypertension, and 22% with previous CVA. During mean follow-up of 20.1 months, 7 patients (41.2%) in elevated troponin and 6 (3.3%) patients in normal troponin group had nonfatal myocardial infarction (P = 0.0001). MACE (41.2% versus 14.2%, P = 0.01) and death from any cause (41.2% versus 14.5%, P = 0.017) were significant in the positive troponin group. Conclusions. Elevated cardiac troponin in patients with acute stroke and no evidence of ACS is strong predictor of long-term cardiac outcomes. PMID:25530906

  13. The Granite Mountain Atmospheric Sciences Testbed (GMAST): A Facility for Long Term Complex Terrain Airflow Studies

    NASA Astrophysics Data System (ADS)

    Zajic, D.; Pace, J. C.; Whiteman, C. D.; Hoch, S.

    2011-12-01

    This presentation describes a new facility at Dugway Proving Ground (DPG), Utah that can be used to study airflow over complex terrain, and to evaluate how airflow over a mountain barrier affects wind patterns over adjacent flatter terrain. DPG's primary mission is to conduct testing, training, and operational assessments of chemical and biological weapon systems. These operations require very precise weather forecasts. Most test operations at DPG are conducted on fairly flat test ranges having uniform surface cover, where airflow patterns are generally well-understood. However, the DPG test ranges are located alongside large, isolated mountains, most notably Granite Mountain, Camelback Mountain, and the Cedar Mountains. Airflows generated over, or influenced by, these mountains can affect wind patterns on the test ranges. The new facility, the Granite Mountain Atmospheric Sciences Testbed, or GMAST, is designed to facilitate studies of airflow interactions with topography. This facility will benefit DPG by improving understanding of how mountain airflows interact with the test range conditions. A core infrastructure of weather sensors around and on Granite Mountain has been developed including instrumented towers and remote sensors, along with automated data collection and archival systems. GMAST is expected to be in operation for a number of years and will provide a reference domain for mountain meteorology studies, with data useful for analysts, modelers and theoreticians. Visiting scientists are encouraged to collaborate with DPG personnel to utilize this valuable scientific resource and to add further equipment and scientific designs for both short-term and long-term atmospheric studies. Several of the upcoming MATERHORN (MountAin TERrain atmospHeric mOdeling and obseRvatioNs) project field tests will be conducted at DPG, giving an example of GMAST utilization and collaboration between DPG and visiting scientists.

  14. Short and Long Term Impacts of Forest Bioenergy Production on Atmospheric Carbon Dioxide Emissions

    NASA Astrophysics Data System (ADS)

    Hudiburg, T.; Law, B. E.; Luyssaert, S.; Thornton, P. E.

    2011-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. The benefit of managing forests for bioenergy substitution of fossil fuels versus potential carbon sequestration by reducing harvest needs to be evaluated. This study uses a combination of Federal Forest Inventory data (FIA), remote sensing, and a coupled carbon-nitrogen ecosystem process model (CLM4-CN) to predict net atmospheric CO2 emissions from forest thinning for bioenergy production in Oregon under varying future management and climate scenarios. We use life-cycle assessment (LCA) incorporating both the forest and forest product sinks and sources of carbon dioxide. Future modeled results are compared with a reduced harvest scenario to determine the potential for increased carbon sequestration in forest biomass. We find that Oregon forests are a current strong sink of 7.5 ± 1.7 Tg C yr-1 or 61 g C m-2 yr-1. (NBP; NEP minus removals from fire and harvest). In the short term, we find that carbon dynamics following harvests for fire prevention and large-scale bioenergy production lead to 2-15% higher emissions over the next 20 years compared to current management, assuming 100% effectiveness of fire prevention. Given the current sink strength, analysis of the forest sector in Oregon demonstrates that increasing harvest levels by all practices above current business-as-usual levels increases CO2 emissions to the atmosphere as long as the region's sink persists. In the long-term, we find that projected changes in

  15. Effects of long-term, elevated ultraviolet-B radiation on phytochemicals in the bark of silver birch (Betula pendula).

    PubMed

    Tegelberg, Riitta; Aphalo, Pedro J; Julkunen-Tiitto, Riitta

    2002-12-01

    Long-term outdoor experiments were conducted to investigate the effects of elevated ultraviolet-B (UV-B, 280-320 nm) radiation on secondary metabolites (phenolics and terpenoids) and the main soluble sugars (sucrose, raffinose and glucose) in the bark of silver birch (Betula pendula Roth) saplings. Saplings were exposed to a constant 50% increase in erythemal UV irradiance (UV-B(CIE); based on the CIE (International Commission on Illumination) erythemal action spectrum) and a small increase in UV-A radiation (320-400 nm) for three growing seasons in an irradiation field in central Finland. Two control groups were used: saplings exposed to ambient radiation and saplings exposed to slightly increased UV-A radiation. Concentrations of sucrose, raffinose and glucose in bark were higher in UV-treated saplings than in saplings grown in ambient radiation, indicating that stem carbohydrate metabolism was changed by long-term elevated UV radiation. Saplings in the elevated UV-A + UV-B radiation treatment and the UV-A radiation control treatment had significantly increased concentrations of certain UV-absorbing phenolics, such as salidroside, 3,4'-dihydroxypropiophenone-3-glucoside, (+)-catechin and (-)-epicatechin compared with saplings in ambient radiation. In contrast, the radiation treatments had no effect on the non-UV-B-absorbing terpenoids, papyriferic acid and deacetylpapyriferic acid. We conclude that plant parts, in addition to leaves, accumulate specific phenolic UV-filters in response to UV radiation exposure. PMID:12464579

  16. Long-Term Intermittent Hypoxia Elevates Cobalt Levels in the Brain and Injures White Matter in Adult Mice

    PubMed Central

    Veasey, Sigrid C.; Lear, Jessica; Zhu, Yan; Grinspan, Judith B.; Hare, Dominic J.; Wang, SiHe; Bunch, Dustin; Doble, Philip A.; Robinson, Stephen R.

    2013-01-01

    Study Objectives: Exposure to the variable oxygenation patterns in obstructive sleep apnea (OSA) causes oxidative stress within the brain. We hypothesized that this stress is associated with increased levels of redox-active metals and white matter injury. Design: Participants were randomly allocated to a control or experimental group (single independent variable). Setting: University animal house. Participants: Adult male C57BL/6J mice. Interventions: To model OSA, mice were exposed to long-term intermittent hypoxia (LTIH) for 10 hours/day for 8 weeks or sham intermittent hypoxia (SIH). Measurements and Results: Laser ablation-inductively coupled plasma-mass spectrometry was used to quantitatively map the distribution of the trace elements cobalt, copper, iron, and zinc in forebrain sections. Control mice contained 62 ± 7 ng cobalt/g wet weight, whereas LTIH mice contained 5600 ± 600 ng cobalt/g wet weight (P < 0.0001). Other elements were unchanged between conditions. Cobalt was concentrated within white matter regions of the brain, including the corpus callosum. Compared to that of control mice, the corpus callosum of LTIH mice had significantly more endoplasmic reticulum stress, fewer myelin-associated proteins, disorganized myelin sheaths, and more degenerated axon profiles. Because cobalt is an essential component of vitamin B12, serum methylmalonic acid (MMA) levels were measured. LTIH mice had low MMA levels (P < 0.0001), indicative of increased B12 activity. Conclusions: Long-term intermittent hypoxia increases brain cobalt, predominantly in the white matter. The increased cobalt is associated with endoplasmic reticulum stress, myelin loss, and axonal injury. Low plasma methylmalonic acid levels are associated with white matter injury in long-term intermittent hypoxia and possibly in obstructive sleep apnea. Citation: Veasey SC; Lear J; Zhu Y; Grinspan JB; Hare DJ; Wang S; Bunch D; Doble PA; Robinson SR. Long-term intermittent hypoxia elevates cobalt

  17. Long-term trend and variability of atmospheric PM10 concentration in the Po Valley

    NASA Astrophysics Data System (ADS)

    Bigi, A.; Ghermandi, G.

    2014-05-01

    The limits to atmospheric pollutant concentration set by the European Commission provide a challenging target for the municipalities in the Po Valley, because of the characteristic climatic conditions and high population density of this region. In order to assess climatology and trends in the concentration of atmospheric particles in the Po Valley, a data set of PM10 data from 41 sites across the Po Valley have been analysed, including both traffic and background sites (either urban, suburban or rural). Of these 41 sites, 18 with 10 yr or longer record have been analysed for long-term trend in deseasonalized monthly means, in annual quantiles and in monthly frequency distribution. A widespread significant decreasing trend has been observed at most sites, up to a few percent per year, by a generalized least squares and Theil-Sen method. All 41 sites have been tested for significant weekly periodicity by Kruskal-Wallis test for mean anomalies and by Wilcoxon test for weekend effect magnitude. A significant weekly periodicity has been observed for most PM10 series, particularly in summer and ascribed mainly to anthropic particulate emissions. A cluster analysis has been applied in order to highlight stations sharing similar pollution conditions over the reference period. Five clusters have been found, two encompassing the metropolitan areas of Turin and Milan and their respective nearby sites and the other three clusters gathering northeast, northwest and central Po Valley sites respectively. Finally, the observed trends in atmospheric PM10 have been compared to trends in provincial emissions of particulates and PM precursors, and analysed along with data on vehicular fleet age, composition and fuel sales. A significant basin-wide drop in emissions occurred for gaseous pollutants, contrarily to emissions of PM10 and PM2.5, whose drop was low and restricted to a few provinces. It is not clear whether the decrease for only gaseous emissions is sufficient to explain the

  18. Long-term outcomes in high-risk patients with non-ST-segment elevation myocardial infarction.

    PubMed

    Cohen, Marc

    2016-04-01

    Greater use of evidence-based therapies has improved outcomes for patients with acute coronary syndromes (ACS) in recent decades. Consequently, more ACS patients are surviving beyond 12 months; however, limited data exist to guide treatment in these patients. Long-term outcomes have not improved in non-ST-segment elevation myocardial infarction (NSTEMI) patients at the same rate seen in ST-segment elevation myocardial infarction patients, possibly reflecting NSTEMI patients' more complex clinical phenotype, including older age, greater burden of comorbidities and higher likelihood of a previous myocardial infarction (MI). This complexity impacts clinical decision-making, particularly in high-risk NSTEMI patients, in whom risk-benefit assessments are problematical. This review examines the need for more effective long-term management of NSTEMI patients who survive ≥12 months after MI. Ongoing risk assessment using objective measures of risk (for bleeding and ischemia) should be used in all post-MI patients. While 12 months appears to be the optimal duration of dual antiplatelet therapy for most patients, this may not be the case for high-risk patients, and more research is urgently needed in this population. A recent subgroup analysis from the DAPT study in patients with or without MI who had undergone coronary stenting (31 % presented with MI; 53 % had NSTEMI) and the prospective PEGASUS-TIMI 54 trial in patients with a prior MI and at least one other risk factor (40 % had NSTEMI) demonstrated that long-term dual antiplatelet therapy improved cardiovascular outcomes but increased bleeding. Further studies will help clarify the role of dual antiplatelet therapy in stable post-NSTEMI patients. PMID:26001907

  19. Beeswax corticosterone implants produce long-term elevation of plasma corticosterone and influence condition.

    PubMed

    Beck, Michelle L; Davies, Scott; Moore, Ignacio T; Schoenle, Laura A; Kerman, Kaan; Vernasco, Ben J; Sewall, Kendra B

    2016-07-01

    Glucocorticoids can play a critical role in modulating life-history trade-offs. However, studying the effects of glucocorticoids on life-history often requires experimentally elevating plasma glucocorticoid concentrations for several weeks within normal physiological limits and without repeated handling of the animal. Recently, implants made of beeswax and testosterone (T) were shown to have release dynamics superior to some currently available T implants, and these beeswax implants dissolved, eliminating the need to recapture the animal. We evaluated the utility of beeswax implants containing four different dosages of corticosterone (CORT; the primary glucocorticoid in birds) and their effect on several condition indices in a captive colony of zebra finches (Taeniopygia guttata). The three implants with the greatest CORT doses (0.05, 0.1, and 0.5mg) produced spikes in plasma CORT concentrations 20h after treatment, but were within the limits that zebra finches may normally experience. The 0.5mg CORT implant elevated plasma CORT between typical baseline and restraint stress levels reported in other studies of zebra finches for the entire 35day experiment. Birds in the 0.5mg implant group were heavier, had greater furcular fat scores, and had lower hematocrit than birds in the control and other CORT implant groups. Beeswax CORT implants are a low cost method of elevating plasma CORT for a prolonged time. Furthermore, because there is no need to remove these implants at the end of a study, this method may be amenable to studies of free-ranging animals. PMID:27222349

  20. Effects of long-term elevated CO2, warming, and prolonged drought on Pleurozium-associated diazotrophic activity and abundance

    NASA Astrophysics Data System (ADS)

    Dyrnum, Kristine; Priemé, Anders; Michelsen, Anders

    2014-05-01

    Nitrogen (N2) fixation is the primary natural influx of N to terrestrial ecosystems, and changes in N2 fixation may have consequences for primary productivity and thus ecosystem function. We studied the activity and abundance of diazotrophs associated with the feather moss Pleurozium schreberi in a temperate heathland, after seven years of global change manipulations, including elevated atmospheric CO2 (510 ppm), increased temperature (0.5-1.5 ° C), and prolonged pre-summer droughts (4-6 weeks /year). Acetylene reduction assay was carried out monthly to monitor N2 fixation rates throughout one year, while nif H copy abundance, serving as a diazotroph abundance estimate, was measured by quantitative polymerase chain reaction (q-PCR). Prolonged summer droughts significantly increased both N2 fixation and nif H copy abundance, contrasting previous studies that demonstrate a direct negative correlation between N2 fixation and water availability. A shift in the relative abundance of N2-fixing bacteria from the green, upper parts of the moss stem to the lower, brown parts was observed. This shift could make diazotrophs less sensitive to desiccation, enabling N2 fixation to be upheld for longer during drought and thus causing higher abundance. Increased temperature likewise had a positive effect on the diazotroph abundance, although this did not translate into increased activity. Possibly, warming protects diazotrophs during extreme cold events, while actual N2 fixation is limited by water, disregarding a rise in potential N2 fixation caused by higher abundance. Increased CO2 caused no significant diazotroph response. Our study showed that long-term increase in temperature and recurrent drought events cause higher diazotroph abundance in Pleurozium schreberi and thus enhance the potential N2 fixations rate. Furthermore, our results indicate that diazotrophs may alter colonization patterns and thereby actively remain in the moss fraction less likely affected by

  1. Comparison of low cost measurement techniques for long-term monitoring of atmospheric ammonia.

    PubMed

    Sutton, M A; Miners, B; Tang, Y S; Milford, C; Wyers, G P; Duyzer, J H; Fowler, D

    2001-10-01

    An inter-comparison of techniques for long-term sampling of atmospheric ammonia (NH3) was conducted with a view to establishing a national network with > 50 sites. Key requirements were for: a low cost system, simplicity and durability to enable a postal exchange with local site operators, a precision of < +/- 20% for monthly sampling at expected NH3 concentrations of 1-2 micrograms m-3, a detection limit sufficient to resolve the small NH3 concentrations (< 0.2 microgram m-3) expected in remote parts of the UK, and a quantitative means to establish quality control. Five sampling methods were compared: A, a commercially available membrane diffusion tube (exposed in triplicate), with membranes removed immediately after sampling; B, the above method, with the membranes left in place until analysis; C, open-ended diffusion tubes (exposed with 4 replicates); D, a new active sampling diffusion denuder system; and E, an active sampling bubbler system. Method D consisted of two 0.1 m acid coated glass denuders in series with sampling at approximately 0.3 l min-1. These methods were deployed at 6 locations in the UK and the Netherlands and compared against reference estimates. Method D was the most precise and sensitive of the techniques compared, with a detection limit of < 0.1 microgram m-3. The bubbler provided a less precise estimate of NH3 concentration, and also suffered several practical drawbacks. The diffusion tubes were found to correlate with the reference at high concentrations (> 3 micrograms m-3), but were less precise and overestimated NH3 at smaller concentrations. Of the passive methods, A was the most precise and C the least precise. On the basis of the results, method D has been implemented in the national network, together with application of method A to explore spatial variability in regions with expected high NH3 concentrations. PMID:11695110

  2. Long-term moderate elevation of corticosterone facilitates avian food-caching behaviour and enhances spatial memory.

    PubMed

    Pravosudov, Vladimir V

    2003-12-22

    It is widely assumed that chronic stress and corresponding chronic elevations of glucocorticoid levels have deleterious effects on animals' brain functions such as learning and memory. Some animals, however, appear to maintain moderately elevated levels of glucocorticoids over long periods of time under natural energetically demanding conditions, and it is not clear whether such chronic but moderate elevations may be adaptive. I implanted wild-caught food-caching mountain chickadees (Poecile gambeli), which rely at least in part on spatial memory to find their caches, with 90-day continuous time-release corticosterone pellets designed to approximately double the baseline corticosterone levels. Corticosterone-implanted birds cached and consumed significantly more food and showed more efficient cache recovery and superior spatial memory performance compared with placebo-implanted birds. Thus, contrary to prevailing assumptions, long-term moderate elevations of corticosterone appear to enhance spatial memory in food-caching mountain chickadees. These results suggest that moderate chronic elevation of corticosterone may serve as an adaptation to unpredictable environments by facilitating feeding and food-caching behaviour and by improving cache-retrieval efficiency in food-caching birds. PMID:14728783

  3. Very Long-Term Prognostic Role of Admission BNP in Non-ST Segment Elevation Acute Coronary Syndrome

    PubMed Central

    Bassan, Fernando; Bassan, Roberto; Esporcatte, Roberto; Santos, Braulio; Tura, Bernardo

    2016-01-01

    Background BNP has been extensively evaluated to determine short- and intermediate-term prognosis in patients with acute coronary syndrome, but its role in long-term mortality is not known. Objective To determine the very long-term prognostic role of B-type natriuretic peptide (BNP) for all-cause mortality in patients with non-ST segment elevation acute coronary syndrome (NSTEACS). Methods A cohort of 224 consecutive patients with NSTEACS, prospectively seen in the Emergency Department, had BNP measured on arrival to establish prognosis, and underwent a median 9.34-year follow-up for all-cause mortality. Results Unstable angina was diagnosed in 52.2%, and non-ST segment elevation myocardial infarction, in 47.8%. Median admission BNP was 81.9 pg/mL (IQ range = 22.2; 225) and mortality rate was correlated with increasing BNP quartiles: 14.3; 16.1; 48.2; and 73.2% (p < 0.0001). ROC curve disclosed 100 pg/mL as the best BNP cut-off value for mortality prediction (area under the curve = 0.789, 95% CI= 0.723-0.854), being a strong predictor of late mortality: BNP < 100 = 17.3% vs. BNP ≥ 100 = 65.0%, RR = 3.76 (95% CI = 2.49-5.63, p < 0.001). On logistic regression analysis, age >72 years (OR = 3.79, 95% CI = 1.62-8.86, p = 0.002), BNP ≥ 100 pg/mL (OR = 6.24, 95% CI = 2.95-13.23, p < 0.001) and estimated glomerular filtration rate (OR = 0.98, 95% CI = 0.97-0.99, p = 0.049) were independent late-mortality predictors. Conclusions BNP measured at hospital admission in patients with NSTEACS is a strong, independent predictor of very long-term all-cause mortality. This study allows raising the hypothesis that BNP should be measured in all patients with NSTEACS at the index event for long-term risk stratification. PMID:26840056

  4. Atmospheric emissions of N2O deduced from long-term observations at the Mediterranean Island of Lampedusa

    NASA Astrophysics Data System (ADS)

    Artuso, Florinda; Piacentino, Salvatore; Sferlazzo, Damiano; Disarra, Alcide; Meloni, Daniela; Monteleone, Francesco; Chamard, Paolo; Frezzotti, Massimo

    2010-05-01

    Nitrous oxide (N2O) is the third principal long-lived greenhouse gas (GHG) emitted by human activities, as it has been assessed by the last Intergovernmental Panel on Climate Change (IPCC) report. It is produced both naturally and anthropogenically. Natural sources include microbial processes of nitrification and denitrification in soils and water. Use of nitrate and ammonium fertilizers increased noteworthy the emission of N2O from soils. Other anthropogenic sources of N2O are fuel combustion and waste management activities. Its mixing ratio in the atmosphere has considerably risen during the past two centuries as demonstrated by analyses of polar ice cores. Long-term observations of GHG atmospheric concentration are crucial in the investigation of global climate changes and are essential for the prediction of their future trends. For this reason a number of global monitoring studies aimed at determining trends and distribution in the tropospheric abundance of N2O and other GHGs have been carried out during the last years. Scarce information on the magnitude and distribution of N2O emissions is available in the Mediterranean area. In this work we present and analyse long-term N2O records measured at the remote site of Lampedusa Island, located in the middle of the Mediterranean basin. Lampedusa is part of the majors GHG global monitoring programs such as the Global Atmosphere Watch (GAW), established by the World Meteorological Organization, and the National Oceanic and Atmospheric Administration (NOAA) networks. Monitoring of the atmospheric mixing ratio of N2O has been started in Lampedusa in 1996 on a weekly basis but also continuous measurements have been carried out since October 2005. Weekly records are analyzed and the linear trend line has been used to evaluate the annual growth rate. In agreement with data reported by the IPCC 4th Assessment Report, the mean N2O value recorded at Lampedusa in this period is 319.6±0.6 ppb. This finding remarks the

  5. Long-term atmospheric visibility trend in Southeast China, 1973-2010

    NASA Astrophysics Data System (ADS)

    Deng, Junjun; Du, Ke; Wang, Kai; Yuan, Chung-Shin; Zhao, Juanjuan

    2012-11-01

    Particulate matter (PM) pollution in Southeast China has been worsening because of the rapid industrial development and urbanization, which have significant negative effects on atmospheric visibility. Characterization of the trend in atmospheric visibility is important for evaluating the impact of PM pollution on the impairment of visual air quality in urban and rural areas. Long-term trend in atmospheric visibility in Southeast China was analyzed for the period of 1973-2010 based on the meteorological data from the National Climatic Data Center (NCDC) database using four statistical methods: annual mean visibility, percentages of “very good” visibility and “bad” visibility, ridit analysis, and cumulative percentiles. The relationship of atmospheric extinction with Air Pollution Index (API) was studied. In addition, the effects of recent environment policies on visibility were studied. The results showed that the visibility had decreased in 94% stations of this region and prefecture stations had the highest decreasing trend of -3.1 km/decade during the entire period. The average visibility of all the 17 stations (i.e., region-average) declined at a rate of -2.0 km/decade, with a 38-year average of 18.1 km. Decrease in the percentage of “very good” visibility and increase in the percentage of “bad” visibility existed in 14 and 16 stations, respectively. Region-average percentage of “bad” visibility was in the range of 2.2-21.5%, with an increasing rate of 5.0% per decade, and that of “very good” visibility was 24.4-71.8%, with a decreasing rate of -10.7% per decade. During the entire period, county and prefecture stations had similar changing patterns and trends in visibility, while town stations had the least worsening trends. Region-average visibility was better before 1988 while worse after 1993 when comparing to the entire period, with the transition period of 1988-1993. The worst 20%, 50% and best 20% of region-average visibility

  6. SEASONAL PHOSPHATASE ACTIVITY IN THREE CHARACTERISTIC SOILS OF THE ENGLISH UPLANDS POLLUTED BY LONG-TERM ATMOSPHERIC NITROGEN DEPOSITION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphomonoesterase activities were determined monthly during a seasonal cycle in three characteristic soil types of the English uplands that have been subject to long-term atmospheric nitrogen deposition. Activities (µmol para-nitrophenol per gram soil dry wt per hour) ranged between 83.9 - 307 in...

  7. Elevated Total Homocysteine Levels in Acute Ischemic Stroke Are Associated With Long-Term Mortality

    PubMed Central

    Shi, Zhihong; Guan, Yalin; Huo, Ya Ruth; Liu, Shuling; Zhang, Meilin; Lu, Hui; Yue, Wei; Wang, Jinhuan

    2015-01-01

    Background and Purpose— Total homocysteine (tHcy) levels are associated with secondary vascular events and mortality after stroke. The aim of this study was to investigate whether tHcy levels in the acute phase of a stroke contribute to the recurrence of cerebro-cardiovascular events and mortality. Methods— A total of 3799 patients were recruited after hospital admission for acute ischemic stroke. Levels of tHcy were measured within 24 hours after primary admission. Patients were followed for a median of 48 months. Results— During the follow-up period, 233 (6.1%) patients died. After adjustment for age, smoking status, diabetes mellitus, and other cardiovascular risk factors, patients in the highest tHcy quartile (>18.6 μmol/L) had a 1.61-fold increased risk of death (adjusted hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.03–2.53) compared with patients in the lowest quartile (≤10 μmol/L). Further subgroup analysis showed that this correlation was only significant in the large-artery atherosclerosis stroke subtype (adjusted HR, 1.80; 95% CI, 1.05–3.07); this correlation was not significant in the small-vessel occlusion subtype (adjusted HR, 0.80; 95% CI, 0.30–2.12). The risk of stroke-related mortality was 2.27-fold higher for patients in the third tHcy quartile (adjusted HR, 2.27; 95% CI, 1.06–4.86) and 2.15-fold more likely for patients in the fourth quartile (adjusted HR, 2.15; 95% CI, 1.01–4.63) than for patients in the lowest tHcy quartile. The risk of cardiovascular-related mortality and the risk of recurrent ischemic stroke were not associated with tHcy levels. Conclusions— Our findings suggest that elevated tHcy levels in the acute phase of an ischemic stroke can predict mortality, especially in stroke patients with the large-vessel atherosclerosis subtype. PMID:26199315

  8. Temporal dynamics of fine roots under long-term exposure to elevated CO2 in the Mojave Desert.

    PubMed

    Sonderegger, Derek L; Ogle, Kiona; Evans, R Dave; Ferguson, Scot; Nowak, Robert S

    2013-04-01

    Deserts are considered 'below-ground dominated', yet little is known about the impact of rising CO(2) in combination with natural weather cycles on long-term dynamics of root biomass. This study quantifies the temporal dynamics of fine-root production, loss and standing crop in an intact desert ecosystem exposed to 10 yr of elevated CO(2). We used monthly minirhizotron observations from 4 yr (2003-2007) for two dominant shrub species and along community transects at the Nevada Desert free-air CO(2) enrichment Facility. Data were synthesized within a Bayesian framework that included effects of CO(2) concentration, cover type, phenological period, antecedent soil water and biological inertia (i.e. the influence of prior root production and loss). Elevated CO(2) treatment interacted with antecedent soil moisture and had significantly greater effects on fine-root dynamics during certain phenological periods. With respect to biological inertia, plants under elevated CO(2) tended to initiate fine-root growth sooner and sustain growth longer, with the net effect of increasing the magnitude of production and mortality cycles. Elevated CO(2) interacts with past environmental (e.g. antecedent soil water) and biological (e.g. biological inertia) factors to affect fine-root dynamics, and such interactions are expected to be important for predicting future soil carbon pools. PMID:23356437

  9. Changes in High Elevation Lake Ecosystems of the Sierra Nevada during the 20th Century: Combining Long-term Monitoring with Paleolimnology

    NASA Astrophysics Data System (ADS)

    Sickman, J. O.; Heard, A. M.; Rose, N. L.; Bennett, D. M.; Lucero, D. M.; Melack, J. M.; Curtis, J. H.

    2014-12-01

    High mountain lakes of the Sierra Nevada are excellent indicators of anthropogenic global change due to their limited capacity to buffer acid deposition, their sensitivity to changes in snowpack dynamics and their oligotrophic nutrient status. In this presentation, we examine long-term records of hydrochemistry and biological monitoring at the Emerald Lake watershed to assess whether high elevation lakes of the Sierra Nevada are changing in response to climate change or changes in atmospheric deposition of nutrients and acid. To provide a broader context for these changes, we augment these long-term records with results from paleolimnological analysis that examines changes in nutrient status and acid buffering capacity of Sierra Nevada lakes over the past two millennia. Our research suggests that, although atmospheric deposition is the dominant driver of twentieth century ANC trends, aquatic communities in the Sierra Nevada are responding to combined effects from acidification, climate change, and eutrophication. Early in the twentieth century the primary stressor effecting Sierra Nevada lakes was acid deposition driven by SO2 emissions. As the century and industrialization progressed, NOx levels increased adding a eutrophication stressor while simultaneously contributing to acidification. Effects were further complicated by a warming climate in the late twentieth century, as warmer temperatures may have contributed to the recovery of ANC in lakes via increased weathering rates, while simultaneously enhancing eutrophication effects.

  10. Is atomic oxygen the primary driver of long-term trends in the ionosphere-upper atmosphere?

    NASA Astrophysics Data System (ADS)

    Laštovička, Jan

    2015-04-01

    Atmospheric climate is changing not only near surface; it changes also in the upper atmosphere, the mesosphere-thermosphere-ionosphere system. The increasing concentration of greenhouse gases is generally accepted to be the main driver of these climatic changes. However, there are also other drivers of long-term changes and trends in the upper atmosphere, namely stratospheric ozone depletion, long-term changes of solar and geomagnetic activity, secular changes of the Earth's magnetic field, long-term changes of atmospheric circulation, of atmospheric wave activity and of mesospheric water vapor concentration. Recently Oliver et al. (2013) and Oliver et al. (2014) suggested two other possibilities of main drivers of trends in the thermosphere and ionosphere, the increasing thermospheric gravity wave activity, and/or the increasing concentration of atomic oxygen near 120 km (base of the thermosphere) due to the decreasing turbopause height. Here I show that these suggestions are not supported by various other data and results, and that the carbon dioxide remains to be the primary trend driver in the upper atmosphere-ionosphere system.

  11. Effects of long-term elevated CO2 treatment on the inner and outer bark chemistry of sweetgum (Liquidambar styraciflua L.) trees

    SciTech Connect

    Eberhardt, Thomas L.; Labbé, Nicole; So, Chi-Leung; Kim, Keonhee; Reed, Karen G.; Leduc, Daniel J.; Warren, Jeffrey M.

    2015-07-23

    Long-term exposure of sweetgum trees to elevated atmospheric CO2 concentrations significantly shifted inner bark (phloem) and outer bark (rhytidome) chemical compositions, having implications for both defense and nutrient cycling. Changes in plant tissue chemistry due to increasing atmospheric carbon dioxide (CO2) concentrations have direct implications for tissue resistance to abiotic and biotic stress while living, and soil nutrient cycling when senesced as litter. Although the effects of elevated CO2 concentrations on tree foliar chemistry are well documented, the effects on tree bark chemistry are largely unknown. The objective of our study was to determine the effects of a long-term elevated CO2 treatment on the contents of individual elements, extractives, ash, lignin, and polysaccharide sugars of sweetgum (Liquidambar styraciflua L.) bark. Trees were harvested from sweetgum plots equipped with the Free-Air CO2 Enrichment (FACE) apparatus, receiving either elevated or ambient CO2 treatments over a 12-year period. Whole bark sections were partitioned into inner bark (phloem) and outer bark (rhytidome) samples before analysis. Moreover, principal component analysis, coupled with either Fourier transform infrared spectroscopy or pyrolysis-gas chromatography-mass spectrometry data, was also used to screen for differences. Elevated CO2 reduced the N content (0.42 vs. 0.35 %) and increased the C:N ratio (109 vs. 136 %) of the outer bark. For the inner bark, elevated CO2 increased the Mn content (470 vs. 815 mg kg-1), total extractives (13.0 vs. 15.6 %), and residual ash content (8.1 vs. 10.8 %) as compared to ambient CO2; differences were also observed for some hemicellulosic sugars, but not lignin. Shifts in bark chemistry can affect the success of herbivores and pathogens in living trees, and as litter, bark can affect the biogeochemical cycling of

  12. Long-term continuous monitoring of mercury in the Russian arctic: winter increase of atmospheric mercury depletion events

    NASA Astrophysics Data System (ADS)

    Pankratov, Fidel; Mahura, Alexander; Popov, Valentin; Katz, Oleg

    2014-05-01

    Among pollutants mercury is a major environmental concern due to its ecological hazard. The mercury can reside in the atmosphere for a long time high, and it is a reason of its global propagation in the Northern Hemisphere and elevated mercury concentrations are reported in the Arctic environment. First time, in 1995, the effect of atmospheric mercury depletion in the troposphere was found at the Canadian station Alert. This phenomenon (called the Atmospheric Mercury Depletion Event - AMDE) is observed during April-June, when the Polar sunrise starts till the end of the snowmelt. The same effect was reported for other polar stations situated to the north of 60° N. Long-term continuous monitoring of gaseous elemental mercury in the surface air at the polar station Amderma (69,720N; 61,620E) using the analyzer Tekran 2537A has been conducted from Jun 2001 to date. Individual measurements were collected every thirty minutes. It has been shown, that during eleven years of observations the AMDEs were observed every year, from the end of March till early June. For the winter period (Dec-Feb) these events of the atmospheric mercury depletion were registered from 2010 to 2013, which had not been observed before. A large number of hours during the day, when the concentration of mercury was recorded at level of below 1 ng/m3, was registered during Dec-Feb. The sun declination above the horizon is negative, and solar activity is still not enough to trigger the photochemical reactions. The these last 3 years confirmed a tendency to displacement of AMDEs to the winter season, which leads to an additional factor entry of mercury in various biological objects, due to the additional deposition of various forms of mercury on the snowpack. At the same time, especially during the winter seasons, there is a substantial increase (up to 8 times) of AMDEs, compared with the previous years. In particular, in winter 2013 the maximum number of AMDs reached 31 cases. The explanation can be

  13. Long-term response of a Mojave Desert winter annual plant community to a whole-ecosystem atmospheric CO2 manipulation (FACE).

    PubMed

    Smith, Stanley D; Charlet, Therese N; Zitzer, Stephen F; Abella, Scott R; Vanier, Cheryl H; Huxman, Travis E

    2014-03-01

    Desert annuals are a critically important component of desert communities and may be particularly responsive to increasing atmospheric (CO2 ) because of their high potential growth rates and flexible phenology. During the 10-year life of the Nevada Desert FACE (free-air CO2 enrichment) Facility, we evaluated the productivity, reproductive allocation, and community structure of annuals in response to long-term elevated (CO2 ) exposure. The dominant forb and grass species exhibited accelerated phenology, increased size, and higher reproduction at elevated (CO2 ) in a wet El Niño year near the beginning of the experiment. However, a multiyear dry cycle resulted in no increases in productivity or reproductive allocation for the remainder of the experiment. At the community level, early indications of increased dominance of the invasive Bromus rubens at elevated (CO2 ) gave way to an absence of Bromus in the community during a drought cycle, with a resurgence late in the experiment in response to higher rainfall and a corresponding high density of Bromus in a final soil seed bank analysis, particularly at elevated (CO2 ). This long-term experiment resulted in two primary conclusions: (i) elevated (CO2 ) does not increase productivity of annuals in most years; and (ii) relative stimulation of invasive grasses will likely depend on future precipitation, with a wetter climate favoring invasive grasses but currently predicted greater aridity favoring native dicots. PMID:24115504

  14. Effects of long-term elevated CO2 treatment on the inner and outer bark chemistry of sweetgum (Liquidambar styraciflua L.) trees

    DOE PAGESBeta

    Eberhardt, Thomas L.; Labbé, Nicole; So, Chi-Leung; Kim, Keonhee; Reed, Karen G.; Leduc, Daniel J.; Warren, Jeffrey M.

    2015-07-23

    Long-term exposure of sweetgum trees to elevated atmospheric CO2 concentrations significantly shifted inner bark (phloem) and outer bark (rhytidome) chemical compositions, having implications for both defense and nutrient cycling. Changes in plant tissue chemistry due to increasing atmospheric carbon dioxide (CO2) concentrations have direct implications for tissue resistance to abiotic and biotic stress while living, and soil nutrient cycling when senesced as litter. Although the effects of elevated CO2 concentrations on tree foliar chemistry are well documented, the effects on tree bark chemistry are largely unknown. The objective of our study was to determine the effects of a long-term elevatedmore » CO2 treatment on the contents of individual elements, extractives, ash, lignin, and polysaccharide sugars of sweetgum (Liquidambar styraciflua L.) bark. Trees were harvested from sweetgum plots equipped with the Free-Air CO2 Enrichment (FACE) apparatus, receiving either elevated or ambient CO2 treatments over a 12-year period. Whole bark sections were partitioned into inner bark (phloem) and outer bark (rhytidome) samples before analysis. Moreover, principal component analysis, coupled with either Fourier transform infrared spectroscopy or pyrolysis-gas chromatography-mass spectrometry data, was also used to screen for differences. Elevated CO2 reduced the N content (0.42 vs. 0.35 %) and increased the C:N ratio (109 vs. 136 %) of the outer bark. For the inner bark, elevated CO2 increased the Mn content (470 vs. 815 mg kg-1), total extractives (13.0 vs. 15.6 %), and residual ash content (8.1 vs. 10.8 %) as compared to ambient CO2; differences were also observed for some hemicellulosic sugars, but not lignin. Shifts in bark chemistry can affect the success of herbivores and pathogens in living trees, and as litter, bark can affect the biogeochemical cycling of nutrients within the forest floor. Our results demonstrate that increasing atmospheric CO2 concentrations

  15. Inter and intra-specific variation in photosynthetic acclimation response to long term exposure of elevated carbon dioxide

    SciTech Connect

    Wilkinson, M. |

    1996-08-01

    The response of intra and interspecific variation in photosynthetic acclimation to growth at elevated atmospheric CO{sub 2} concentration (600{micro}mol mol-l) in six important grassland species was investigated. Plants were grown in a background sward of Lolium perenne and measurements were made after four years of growth at elevated C{sub a}. Elevated CO{sub 2} was maintained using a FACE (Free-Air Carbon Enrichment) system. Significant intra and interspecific variation in acclimation response was demonstrated. The response of adaxial and abaxial stomatal conductance to elevated CO{sub 2} was also investigated. The stomatal conductance of both the adaxial and abaxial leaf surfaces was found to be reduced by elevated C{sub a}. Significant asymmetric responses in stomatal conductance was demonstrated in D. glomerata and T. pratense. Analysis of stomatal indices and densities indicated that the observed reductions in stomatal conductance were probably the result of changes in stomatal aperture.

  16. The role of abiotic conditions in shaping the long-term patterns of a high-elevation Argentine ant invasion

    USGS Publications Warehouse

    Krushelnycky, P.D.; Joe, S.M.; Medeiros, A.C.; Daehler, C.C.; Loope, L.L.

    2005-01-01

    Analysis of long-term patterns of invasion can reveal the importance of abiotic factors in influencing invasion dynamics, and can help predict future patterns of spread. In the case of the invasive Argentine ant (Linepithema humile), most prior studies have investigated this species' limitations in hot and dry climates. However, spatial and temporal patterns of spread involving two ant populations over the course of 30 years at a high elevation site in Hawaii suggest that cold and wet conditions have influenced both the ant's distribution and its rate of invasion. In Haleakala National Park on Maui, we found that a population invading at lower elevation is limited by increasing rainfall and presumably by associated decreasing temperatures. A second, higher elevation population has spread outward in all directions, but rates of spread in different directions appear to have been strongly influenced by differences in elevation and temperature. Patterns of foraging activity were strongly tied to soil temperatures, supporting the hypothesis that variation in temperature can influence rates of spread. Based on past patterns of spread, we predicted a total potential range that covers nearly 50% of the park and 75% of the park's subalpine habitats. We compared this rough estimate with point predictions derived from a degree-day model for Argentine ant colony reproduction, and found that the two independent predictions match closely when soil temperatures are used in the model. The cold, wet conditions that have influenced Argentine ant invasion at this site are likely to be influential at other locations in this species' current and future worldwide distribution. ?? 2005 Blackwell Publishing Ltd.

  17. Relationships Between Long-term Atmospheric Wet Deposition and Stream Chemistry in Mid-Appalachian Forest Catchments

    NASA Astrophysics Data System (ADS)

    DeWalle, D. R.; Boyer, E. W.; Buda, A. R.

    2014-12-01

    Improved understanding of the link between atmospheric deposition and surface water quality is critical to assessing the degree to which forested watersheds have recovered from acidification. This presentation draws upon long-term (1982-2013) atmospheric wet deposition and stream chemistry time series to study how changes in atmospheric chemical inputs have been propagated to stream waters. We used autocorrelation and lagged cross-correlation techniques to analyze monthly time series describing variations of chloride, sulfate and inorganic nitrogen concentrations for four pairs of stream/deposition monitoring sites. Autocorrelation analysis revealed that individual atmospheric input time series of sulfate and inorganic nitrogen were strongly seasonal, while chloride inputs exhibited little seasonality. Stream chemistry time series exhibited gradually declining autocorrelation trends with increasing lag times suggesting that atmospheric input signals were variably damped by the forest ecosystems . Lagged cross-correlation between raw atmospheric and stream chemistry time series indicated gradual decreases in correlation within superimposed regular annual cycles of correlation over 10- 15 years of lag time. Pre-whitening of each atmospheric and stream time series using regression or ARIMA models removed the influence of long-term trends, seasonal cycles and other factors and revealed occurrence of relatively few and highly variable lag times with significant correlations. While lagged cross-correlation of raw time series data provided some useful insights into the long-term trend and seasonal nature of the linkages between atmospheric deposition and stream chemistry, cross-correlation of shorter-term residual variations after prewhitening did not produce a consistent pattern of lag times with significant correlations in our monthly time series data.

  18. Long-term effects of elevated UV-B radiation on photosynthesis and ultrastructure of Eriophorum russeolum and Warnstorfia exannulata.

    PubMed

    Haapala, Jaana K; Mörsky, Sami K; Saarnio, Sanna; Suokanerva, Hanne; Kyrö, Esko; Silvola, Jouko; Holopainen, Toini

    2010-12-15

    The depletion of stratospheric ozone above the Arctic regions may increase the amount of UV-B radiation to which the northern ecosystems are exposed. In this paper, we examine the hypothesis that supplemental UV-B radiation may affect the growth rate and photosynthesis of boreal peatland plants and could thereby affect the carbon uptake of these ecosystems. In this study, we report the effects of 3-year exposure to elevated UV-B radiation (46% above ambient) on the photosynthetic performance and ultrastructure of a boreal sedge Eriophorum russeolum and a moss Warnstorfia exannulata. The experiment was conducted on a natural fen ecosystem at Sodankylä in northern Finland. The effects of UV-B radiation on the light response of E. russeolum CO(2) assimilation and the maximal photochemical efficiency of photosystem II in a dark-adapted state (F(v)/F(m)) were measured in the field. In addition, the effect of supplemental UV-B radiation on organelles of photosynthetic cells was studied by electron microscopy. The UV-B treatment had no effect on the CO(2) assimilation rate of either species, nor did it affect the structure of the cell organelles. On chlorophyll fluorescence, the UV-B exposure had only a temporary effect during the third exposure year. Our results suggested that in a natural ecosystem, even long-term exposure to reasonably elevated UV-B radiation levels does not affect the photosynthesis of peatland plants. PMID:21062664

  19. Response to Comment on “Long-term climate forcing by atmospheric oxygen concentrations”

    NASA Astrophysics Data System (ADS)

    Poulsen, Christopher J.; Tabor, Clay; White, Joseph

    2016-07-01

    Goldblatt argues that a decrease in pressure broadening of absorption lines in an atmosphere with low oxygen leads to an increase in outgoing longwave radiation and atmospheric cooling. We demonstrate that cloud and water vapor feedbacks in a global climate model compensate for these decreases and lead to atmospheric warming.

  20. Response to Comment on "Long-term climate forcing by atmospheric oxygen concentrations".

    PubMed

    Poulsen, Christopher J; Tabor, Clay; White, Joseph

    2016-07-01

    Goldblatt argues that a decrease in pressure broadening of absorption lines in an atmosphere with low oxygen leads to an increase in outgoing longwave radiation and atmospheric cooling. We demonstrate that cloud and water vapor feedbacks in a global climate model compensate for these decreases and lead to atmospheric warming. PMID:27387944

  1. The long-term evolutions and the regional characteristics of atmospheric methane concentrations in Nagoya, 1983-1997.

    PubMed

    Ito, A; Takahashi, I; Nagata, Y; Chiba, K; Haraguchi, H

    2000-12-18

    This study provides information on the long-term evolutions of the atmospheric methane (CH4) concentrations in Nagoya City, Japan, which were analyzed by using the continuous monitoring data observed at the eight observatory stations for 1983-1997. The 15-year records of the atmospheric CH4 concentrations were examined by means of a time-series analysis using a fast Fourier transform with a low-pass filter to elucidate the seasonal cycles and the long-term trends. The annual averages of the CH4 concentrations in Nagoya were 1.85 ppmv (parts per million by volume), 1.91 ppmv, and 1.90 ppmv in 1988, 1995 and 1997, respectively. Moreover, the annual average growth rate showed a drastic decrease from 17 ppbv (parts per billion by volume) year(-1) in 1992 to 2 ppbv year(-1) in 1993, and further down to 7 ppbv year(-1) in 1997. Comparison of the atmospheric CH4 records in Nagoya with those in global air of the northern hemisphere observed at Mauna Loa observatory in Hawaii, USA, allows us to estimate the excess concentration of CH4 in the urban atmosphere of Nagoya, which was 0.17 ppmv in 1988 and 0.15 ppmv in 1997. On a local scale, the atmospheric CH4 concentrations in the northern part of Nagoya City increased until 1992 and then gradually decreased from 1993 to 1997, although those in the south-western urban areas constantly increased at the averaged growth rate of 13 ppbv year(-1) for 1988-1997. The variation of the long-term trends of the CH4 concentrations in Nagoya may be ascribed to the emission changes from the CH4 sources due to the human activities such as waste dumping and landfills. PMID:11194161

  2. Glacial ice composition: A potential long-term record of the chemistry of atmospheric deposition, Wind River Range, Wyoming

    SciTech Connect

    Naftz, D.L. ); Rice, J.A. ); Ranville, J.R. )

    1991-06-01

    During a reconnaissance study, ice samples were collected from Knife Point glacier to determine if glaciers in the Wind River Range Could provide a long-term record of the chemical composition of wet deposition. Eight annual ice layers comprising the years 1980-1987 were identified. The concentration of calcium, chloride, and sulfate in the annual-weighted wet deposition samples collected at the National Atmospheric deposition Program (NADP) station near Pinedale, Wyoming, showed a significant, positive correlation to the concentration of the same major ions in composite samples from the annual ice layers. results of the study imply that continuous ice cores reaching to the deeper parts of glaciers in the Wind River Range could provide long-term records of the chemical composition of wet deposition.

  3. Long Term Variations of the Atmospheric Air Pollutants in Istanbul City

    PubMed Central

    Ozcan, H. Kurtulus

    2012-01-01

    High population density and intense industrial activity has resulted in various forms of pollution in megacities. Air pollution ranks at the top of this list. This study investigated long-term changes in air pollutant parameters (SO2, CO, NO, NO2, NOx) in Istanbul City, Turkey, using data from air-quality measurement stations on the Asian and European sides of Istanbul. The results show decreases from 2002 to 2010 in the amounts of SO2 (one of the main pollutants released as a result of the burning of fossil fuels) and CO (indicative of incomplete combustion). However, NOx concentrations showed fluctuations over time, rather than a steady decline throughout the study period. PMID:22690163

  4. Long-term trends in the frequency of atmospheric circulation types in European regions

    NASA Astrophysics Data System (ADS)

    Cahynová, M.; Huth, R.

    2009-04-01

    We have analyzed long-term linear trends in the seasonal frequency of circulation types in the period 1957-2002 using 73 circulation classifications arising from the COST733 Action: 65 objective catalogues in Europe and 11 European regions, and 8 subjective and "objectivized" catalogues in Central Europe. The objective catalogues are based on the same gridded climatic data (ECMWF ERA40), but they differ in the classification method used and in the number of circulation types. In the objective catalogues the proportion of days that belong to circulation types with significant trends in seasonal frequency is mostly very low except for Central and Eastern Europe in winter and the Mediterranean in winter and summer. Generally, the magnitude of trends is the highest in winter. In the Mediterranean in summer the types with significant trends in frequency are the prevailing ones, whereas in other seasons and regions there is no such preference for the total occurrence of the circulation type to have a significant trend. In the subjective catalogues there is a substantial proportion of circulation types with significant trends in frequency in all seasons. The magnitude of trends is also very similar within the four seasons. Whether these long-term trends in the subjective catalogues reflect real climatic changes or result from manual data evaluation is still an open question. The research is conducted within the COST733 Action "Harmonisation and Applications of Weather Types Classifications for European Regions". The Czech participation in it is supported by the Ministry of Education, Youth, and Sports of the Czech Republic, contract OC115.

  5. Long-Term Outcomes in Survivors of Early Ventricular Arrhythmias After Acute ST-Elevation and Non-ST-Elevation Myocardial Infarction Treated With Percutaneous Coronary Intervention.

    PubMed

    Liang, Jackson J; Fender, Erin A; Cha, Yong-Mei; Lennon, Ryan J; Prasad, Abhiram; Barsness, Gregory W

    2016-03-01

    Guidelines do not recommend an implantable cardioverter defibrillator (ICD) for prevention of sudden death in patients who develop ventricular arrhythmia (VA) within 48 hours of acute myocardial infarction (AMI) if they are successfully revascularized. We aimed to determine long-term survival in a cohort of early VA survivors treated with percutaneous coronary intervention (PCI) and to determine whether certain high-risk characteristics predicted worse outcomes. This retrospective study included all patients with early VA after AMI treated with PCI at our institution from 2002 to 2012 who survived to hospital discharge. Patients who had an ICD before their index AMI and those who received ICD before hospital discharge were excluded. Overall survival in the early VA survivors was analyzed based on post-MI left ventricular ejection fraction (LVEF) (≥50% vs <50%), MI type (ST-segment elevation myocardial infarction [STEMI] vs non-ST-segment elevation myocardial infarction [NSTEMI]), and single-vessel versus multivessel disease. Baseline presenting clinical and PCI characteristics plus outcomes were compared with matched controls with PCI-treated AMI but no early VA. Of the 79 early VA survivors treated with PCI, there were no significant differences in long-term overall survival between AMI type (STEMI vs NSTEMI), single-vessel versus multivessel disease, and LVEF at time of MI (>50% vs <50%). Despite having lower presenting LVEF (46% vs 55%, p <0.001) and higher rates of cardiogenic shock (28% vs 4%; p <0.001), survivors of early VA had similar overall survival compared with PCI-treated controls whose post-AMI hospital course was not complicated by early VA (p = 0.61). In conclusion, patients with early VA treated with PCI who survive to discharge were more likely to have STEMI, lower LVEF, and cardiogenic shock. Type of AMI or the presence of systolic dysfunction or multivessel disease did not predict long-term mortality. With early PCI, early VA survivors have

  6. CLIMATE CHANGE. Long-term climate forcing by atmospheric oxygen concentrations.

    PubMed

    Poulsen, Christopher J; Tabor, Clay; White, Joseph D

    2015-06-12

    The percentage of oxygen in Earth's atmosphere varied between 10% and 35% throughout the Phanerozoic. These changes have been linked to the evolution, radiation, and size of animals but have not been considered to affect climate. We conducted simulations showing that modulation of the partial pressure of oxygen (pO2), as a result of its contribution to atmospheric mass and density, influences the optical depth of the atmosphere. Under low pO2 and a reduced-density atmosphere, shortwave scattering by air molecules and clouds is less frequent, leading to a substantial increase in surface shortwave forcing. Through feedbacks involving latent heat fluxes to the atmosphere and marine stratus clouds, surface shortwave forcing drives increases in atmospheric water vapor and global precipitation, enhances greenhouse forcing, and raises global surface temperature. Our results implicate pO2 as an important factor in climate forcing throughout geologic time. PMID:26068848

  7. Dryland biological soil crust cyanobacteria show unexpected decreases in abundance under long-term elevated CO2

    USGS Publications Warehouse

    Steven, Blaire; Gallegos-Graves, La Verne; Yeager, Chris M.; Belnap, Jayne; Evans, R. David; Kuske, Cheryl R.

    2012-01-01

    Biological soil crusts (biocrusts) cover soil surfaces in many drylands globally. The impacts of 10 years of elevated atmospheric CO2 on the cyanobacteria in biocrusts of an arid shrubland were examined at a large manipulated experiment in Nevada, USA. Cyanobacteria-specific quantitative PCR surveys of cyanobacteria small-subunit (SSU) rRNA genes suggested a reduction in biocrust cyanobacterial biomass in the elevated CO2 treatment relative to the ambient controls. Additionally, SSU rRNA gene libraries and shotgun metagenomes showed reduced representation of cyanobacteria in the total microbial community. Taxonomic composition of the cyanobacteria was similar under ambient and elevated CO2 conditions, indicating the decline was manifest across multiple cyanobacterial lineages. Recruitment of cyanobacteria sequences from replicate shotgun metagenomes to cyanobacterial genomes representing major biocrust orders also suggested decreased abundance of cyanobacteria sequences across the majority of genomes tested. Functional assignment of cyanobacteria-related shotgun metagenome sequences indicated that four subsystem categories, three related to oxidative stress, were differentially abundant in relation to the elevated CO2 treatment. Taken together, these results suggest that elevated CO2 affected a generalized decrease in cyanobacteria in the biocrusts and may have favoured cyanobacteria with altered gene inventories for coping with oxidative stress.

  8. Dryland biological soil crust cyanobacteria show unexpected decreases in abundance under long-term elevated CO2.

    PubMed

    Steven, Blaire; Gallegos-Graves, La Verne; Yeager, Chris M; Belnap, Jayne; Evans, R David; Kuske, Cheryl R

    2012-12-01

    Biological soil crusts (biocrusts) cover soil surfaces in many drylands globally. The impacts of 10 years of elevated atmospheric CO2 on the cyanobacteria in biocrusts of an arid shrubland were examined at a large manipulated experiment in Nevada, USA. Cyanobacteria-specific quantitative PCR surveys of cyanobacteria small-subunit (SSU) rRNA genes suggested a reduction in biocrust cyanobacterial biomass in the elevated CO2 treatment relative to the ambient controls. Additionally, SSU rRNA gene libraries and shotgun metagenomes showed reduced representation of cyanobacteria in the total microbial community. Taxonomic composition of the cyanobacteria was similar under ambient and elevated CO2 conditions, indicating the decline was manifest across multiple cyanobacterial lineages. Recruitment of cyanobacteria sequences from replicate shotgun metagenomes to cyanobacterial genomes representing major biocrust orders also suggested decreased abundance of cyanobacteria sequences across the majority of genomes tested. Functional assignment of cyanobacteria-related shotgun metagenome sequences indicated that four subsystem categories, three related to oxidative stress, were differentially abundant in relation to the elevated CO2 treatment. Taken together, these results suggest that elevated CO2 affected a generalized decrease in cyanobacteria in the biocrusts and may have favoured cyanobacteria with altered gene inventories for coping with oxidative stress. PMID:23116182

  9. Long-term changes in the aerosol optical thickness in moscow and correction under strong atmospheric turbidity

    NASA Astrophysics Data System (ADS)

    Gorbarenko, E. V.; Rublev, A. N.

    2016-03-01

    We have estimated and compensated the error in long-term series of the aerosol optical thickness (AOT) calculated from the data on direct integral solar radiation measured by a standard actinometer at the Meteorological Observatory of the Moscow State University (MO MSU) for strong atmospheric turbidity conditions. The necessary corrections have been obtained by the Monte-Carlo simulation of the actinometry measurements for different atmospheric conditions, taking into account the angular size of the field of view of the instrument; and a special correctional formula has been obtained. This correction formula has been applied for all timed AOT values of above 0.5 observed at the MO MSU for the entire time period from 1955 to 2013. Changes in the long-term average AOT values in Moscow occurred only when the smoky haze from the forest and peat fires affected the aerosol turbidity of the atmosphere. Here, the significant decreasing trend of aerosol optical depth of the atmosphere from 1955 to 2013 has been retained with the same confidence level.

  10. Atmospheric Chemistry Experiment (ACE) Measurements of Tropospheric and Stratospheric Chemistry and Long-Term Trends

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Bernath, Peter; Boone, Chris; Nassar, Ray

    2007-01-01

    We highlight chemistry and trend measurement results from the Atmospheric Chemistry Experiment (ACE) which is providing precise middle troposphere to the lower thermosphere measurements with a 0.02/cm resolution Fourier transform spectrometer covering 750-4400/cm

  11. Improving the long-term cycling performance of lithium-ion batteries at elevated temperature with electrolyte additives

    NASA Astrophysics Data System (ADS)

    Xia, Jian; Ma, Lin; Dahn, J. R.

    2015-08-01

    The effects of vinylene carbonate-based and prop-1-ene-1,3-sultone-based electrolyte additives on the cycling behavior of Li[Ni1/3Mn1/3Co1/3]O2/graphite pouch type cells at elevated temperature have been systematically studied. Capacity fade during cycling, charge-transfer resistance before and after cycling as well as gas evolution during formation and also during cycling were examined and compared. For vinylene carbonate-based additive blends, only 3% vinylene carbonate, 2% vinylene carbonate + 1% 1,3,2-dioxathiolane-2,2-dioxide + 1% tris(trimethylsilyl) phosphite or 2% vinylene carbonate + 1% methylene methyl disulfonate + 1% tris(trimethylsilyl) phosphite showed less capacity fade than 2% vinylene carbonate alone. Cells with all of these vinylene carbonate-based electrolyte additive blends lost more than 20% of their initial capacity after ∼1000 cycles at 55 °C and all the vinylene carbonate-based cells swelled more than 10% of their initial volume during this test. Cells containing all prop-1-ene-1,3-sultone-based additive blends generally produced much less gas than the vinylene carbonate-based blends. Many cells containing prop-1-ene-1,3-sultone-based additive blends lost less than 20% of their initial capacity after 1000 cycles. Moreover, the impedance of these prop-1-ene-1,3-sultone-based electrolytes decreased after long-term cycling. These results suggest that prop-1-ene-1,3-sultone-based electrolytes are more useful than vinylene carbonate-based electrolytes at high temperatures in Li[Ni1/3Mn1/3Co1/3]O2/graphite cells.

  12. Comment on “Long-term climate forcing by atmospheric oxygen concentrations”

    NASA Astrophysics Data System (ADS)

    Goldblatt, Colin

    2016-07-01

    Poulsen et al. (Reports, 12 June 2015, p. 1238) argued that lower atmospheric oxygen levels during the Phanerozoic would have given a warmer climate. However, radiative and atmospheric structure changes under lower pressure both cause cooling, making their result unusual in that a hierarchy of models gives opposing results. Scrutiny of how radiative and cloud processes were represented, and a mechanistic explanation of the results, are required.

  13. Comment on "Long-term climate forcing by atmospheric oxygen concentrations".

    PubMed

    Goldblatt, Colin

    2016-07-01

    Poulsen et al (Reports, 12 June 2015, p. 1238) argued that lower atmospheric oxygen levels during the Phanerozoic would have given a warmer climate. However, radiative and atmospheric structure changes under lower pressure both cause cooling, making their result unusual in that a hierarchy of models gives opposing results. Scrutiny of how radiative and cloud processes were represented, and a mechanistic explanation of the results, are required. PMID:27387943

  14. Long-term decline of global atmospheric ethane concentrations and implications for methane.

    PubMed

    Simpson, Isobel J; Sulbaek Andersen, Mads P; Meinardi, Simone; Bruhwiler, Lori; Blake, Nicola J; Helmig, Detlev; Rowland, F Sherwood; Blake, Donald R

    2012-08-23

    After methane, ethane is the most abundant hydrocarbon in the remote atmosphere. It is a precursor to tropospheric ozone and it influences the atmosphere's oxidative capacity through its reaction with the hydroxyl radical, ethane's primary atmospheric sink. Here we present the longest continuous record of global atmospheric ethane levels. We show that global ethane emission rates decreased from 14.3 to 11.3 teragrams per year, or by 21 per cent, from 1984 to 2010. We attribute this to decreasing fugitive emissions from ethane's fossil fuel source--most probably decreased venting and flaring of natural gas in oil fields--rather than a decline in its other major sources, biofuel use and biomass burning. Ethane's major emission sources are shared with methane, and recent studies have disagreed on whether reduced fossil fuel or microbial emissions have caused methane's atmospheric growth rate to slow. Our findings suggest that reduced fugitive fossil fuel emissions account for at least 10-21 teragrams per year (30-70 per cent) of the decrease in methane's global emissions, significantly contributing to methane's slowing atmospheric growth rate since the mid-1980s. PMID:22914166

  15. Long-term atmospheric deposition of nitrogen, phosphorus and sulfate in a large oligotrophic lake

    PubMed Central

    Craft, James A.; Stanford, Jack A.

    2015-01-01

    We documented significantly increasing trends in atmospheric loading of ammonium (NH4) and nitrate/nitrite (NO2/3) and decreasing trends in total phosphorus (P) and sulfate (SO4) to Flathead Lake, Montana, from 1985 to 2004. Atmospheric loading of NO2/3 and NH4 increased by 48 and 198% and total P and SO4 decreased by 135 and 39%. The molar ratio of TN:TP also increased significantly. Severe air inversions occurred periodically year-round and increased the potential for substantial nutrient loading from even small local sources. Correlations between our loading data and various measures of air quality in the basin (e.g., particulate matter <10 µm in size, aerosol fine soil mass, aerosol nutrient species, aerosol index, hectares burned) suggest that dust and smoke are important sources. Ammonium was the primary form of N in atmospheric deposition, whereas NO3 was the primary N form in tributary inputs. Atmospheric loading of NH4 to Flathead Lake averaged 44% of the total load and on some years exceeded tributary loading. Primary productivity in the lake is colimited by both N and P most of the year; and in years of high atmospheric loading of inorganic N, deposition may account for up to 6.9% of carbon converted to biomass. PMID:25802810

  16. Long-term atmospheric deposition of nitrogen, phosphorus and sulfate in a large oligotrophic lake.

    PubMed

    Ellis, Bonnie K; Craft, James A; Stanford, Jack A

    2015-01-01

    We documented significantly increasing trends in atmospheric loading of ammonium (NH4) and nitrate/nitrite (NO2/3) and decreasing trends in total phosphorus (P) and sulfate (SO4) to Flathead Lake, Montana, from 1985 to 2004. Atmospheric loading of NO2/3 and NH4 increased by 48 and 198% and total P and SO4 decreased by 135 and 39%. The molar ratio of TN:TP also increased significantly. Severe air inversions occurred periodically year-round and increased the potential for substantial nutrient loading from even small local sources. Correlations between our loading data and various measures of air quality in the basin (e.g., particulate matter <10 µm in size, aerosol fine soil mass, aerosol nutrient species, aerosol index, hectares burned) suggest that dust and smoke are important sources. Ammonium was the primary form of N in atmospheric deposition, whereas NO3 was the primary N form in tributary inputs. Atmospheric loading of NH4 to Flathead Lake averaged 44% of the total load and on some years exceeded tributary loading. Primary productivity in the lake is colimited by both N and P most of the year; and in years of high atmospheric loading of inorganic N, deposition may account for up to 6.9% of carbon converted to biomass. PMID:25802810

  17. Long term changes in reflectivity and large scale motions in the atmosphere of Jupiter and Saturn

    NASA Technical Reports Server (NTRS)

    Beebe, Reta

    1991-01-01

    An observational study was made that used a CCD camera and multicolor filters with a committed f/40 60 cm telescope to image the temporal changes in Jupiter's and Saturn's atmospheres. The intent was to maintain a continuous data base to assist in relating the Voyager data with that of Galileo and Cassini.

  18. An analytical system enabling consistent and long-term measurement of atmospheric dimethyl sulfide

    NASA Astrophysics Data System (ADS)

    Jang, Sehyun; Park, Ki-Tae; Lee, Kitack; Suh, Young-Sang

    2016-06-01

    We describe here an analytical system capable of continuous measurement of atmospheric dimethylsulfide (DMS) at pptv levels. The system uses customized devices for detector calibration and for DMS trapping and desorption that are controlled using a data acquisition system (based on Visual Basic 6.0/C 6.0) designed to maximize the efficiency of DMS analysis in a highly sensitive pulsed flame photometric detector housed in a gas chromatograph. The fully integrated system, which can sample approximately 6 L of air during a 1-hr sampling, was used to measure the atmospheric DMS mixing ratio over the Atlantic sector of the Arctic Ocean over 3 full annual growth cycles of phytoplankton in 2010, 2014, and 2015, with minimal routine maintenance and interruptions. During the field campaigns, the measured atmospheric DMS mixing ratio varied over a considerable range, from <1.5 pptv to maximum levels of 298 pptv in 2010, 82 pptv in 2014, and 429 pptv in 2015. The operational period covering the 3 full annual growth cycles of phytoplankton showed that the system is suitable for uninterrupted measurement of atmospheric DMS mixing ratios in extreme environments. Moreover, the findings obtained using the system showed it to be useful in identifying ocean DMS source regions and changes in source strength.

  19. Long-term Simulations of Pluto's Atmosphere and Surface as a Coupled System

    NASA Astrophysics Data System (ADS)

    Zalucha, Angela M.

    2015-11-01

    Previous work has modeled either Pluto's atmosphere or surface/subsurface as separate entities. In reality, these two regions should be coupled energetically and physically because of the accumulation, sublimation, and transport of volatiles (here, N2). Simulation results over multi-Pluto years are presented from a general circulation model that has both detailed atmospheric and surface/subsurface modules. As the initial model conditions that will ultimately reproduce the observed surface pressures from New Horizons, stellar occultation data, and spectroscopic observations are not known, by trial and error the model is initialized with different surface pressures and amounts of surface ice (collectively known as the volatile inventory). This “brute force” method is now a viable strategy given the ongoing development of the Pluto general circulation model (based on the MIT general circulation model dynamical core; Zalucha & Michaels 2013) and modern supercomputing power. The coupled atmosphere and surface/subsurface model is run until a yearly repeatable frost cycle occurs (if at all). Surface coverage of volatiles and surface pressure will be presented from the various scenarios. Ancillary variables such temperature (of both the atmosphere and surface/subsurface) and wind direction and magnitude will also be shown for cases of particular interest.

  20. Long-term growth of soybean at elevated [CO2] does not cause acclimation of stomatal conductance under fully open-air conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurately predicting plant function and global biogeochemical cycles later this century will be complicated if stomatal conductance (gs) acclimates to growth at elevated [CO2], in the sense of a long-term alteration of the response of gs to [CO2], humidity (h) and/or photosynthetic rate (A). If so,...

  1. LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir Model v2.0.4

    NASA Astrophysics Data System (ADS)

    Zeebe, R. E.

    2012-01-01

    The LOSCAR model is designed to efficiently compute the partitioning of carbon between ocean, atmosphere, and sediments on time scales ranging from centuries to millions of years. While a variety of computationally inexpensive carbon cycle models are already available, many are missing a critical sediment component, which is indispensable for long-term integrations. One of LOSCAR's strengths is the coupling of ocean-atmosphere routines to a computationally efficient sediment module. This allows, for instance, adequate computation of CaCO3 dissolution, calcite compensation, and long-term carbon cycle fluxes, including weathering of carbonate and silicate rocks. The ocean component includes various biogeochemical tracers such as total carbon, alkalinity, phosphate, oxygen, and stable carbon isotopes. LOSCAR's configuration of ocean geometry is flexible and allows for easy switching between modern and paleo-versions. We have previously published applications of the model tackling future projections of ocean chemistry and weathering, pCO2 sensitivity to carbon cycle perturbations throughout the Cenozoic, and carbon/calcium cycling during the Paleocene-Eocene Thermal Maximum. The focus of the present contribution is the detailed description of the model including numerical architecture, processes and parameterizations, tuning, and examples of input and output. Typical CPU integration times of LOSCAR are of order seconds for several thousand model years on current standard desktop machines. The LOSCAR source code in C can be obtained from the author by sending a request to loscar.model@gmail.com.

  2. Long-Term Corrosion of Copper in Hot and Dry Atmosphere in Turpan, China

    NASA Astrophysics Data System (ADS)

    Kong, D. C.; Dong, C. F.; Fang, Y. H.; Xiao, K.; Guo, C. Y.; He, G.; Li, X. G.

    2016-07-01

    Atmospheric exposure tests were conducted on pure copper exposed to the atmosphere for a four-year period in Turpan, China, a typical hot and dry environment. The experiments included weight-loss tests, morphology observations, composition analyses, and electrochemical techniques. The results indicated that the annual corrosion rate of pure copper was approximately 2.24 g/m2/year, and an uneven distribution of corrosion products was observed by scanning electron microscopy. This was attributed to the dehydration process that occurred during wet-dry and cold-hot cycles. The corrosion products mainly comprised cuprite (Cu2O) and atacamite (Cu2Cl(OH)3). Electrochemical measurements showed that deposits on copper improved its resistance to corrosion, but the protectiveness decreased with increasing temperature.

  3. Long-Term Corrosion of Copper in Hot and Dry Atmosphere in Turpan, China

    NASA Astrophysics Data System (ADS)

    Kong, D. C.; Dong, C. F.; Fang, Y. H.; Xiao, K.; Guo, C. Y.; He, G.; Li, X. G.

    2016-05-01

    Atmospheric exposure tests were conducted on pure copper exposed to the atmosphere for a four-year period in Turpan, China, a typical hot and dry environment. The experiments included weight-loss tests, morphology observations, composition analyses, and electrochemical techniques. The results indicated that the annual corrosion rate of pure copper was approximately 2.24 g/m2/year, and an uneven distribution of corrosion products was observed by scanning electron microscopy. This was attributed to the dehydration process that occurred during wet-dry and cold-hot cycles. The corrosion products mainly comprised cuprite (Cu2O) and atacamite (Cu2Cl(OH)3). Electrochemical measurements showed that deposits on copper improved its resistance to corrosion, but the protectiveness decreased with increasing temperature.

  4. Interannual and Long-Term Changes in Middle Atmosphere Temperature from Haloe

    NASA Technical Reports Server (NTRS)

    Remsbwerg, Ellis; Deaver, Lance

    2003-01-01

    Radiative models of the middle atmosphere indicate that the largest temperature response due to steadily increasing amounts of atmospheric CO2 should occur at pressure altitudes between 1 and 0.1 hPa (about 48 to 64 km) and be of the order of 0.5 to 0.6 K/decade on a pressure surface . Such a rate assumes that there is no trend in ozone or in the dissipation of wave activity for that region of the middle atmosphere. This rate of cooling is only of the order of 0.20 to 0.25% per decade, which is a small trend to discern from observations. We have analyzed the 11-year, Version 19 (or V19) temperature versus pressure profile (or T(p)) time series from the UARS Halogen Occultation Experiment (HALOE) for such trends at selected pressure levels. The HALOE T(p) time series are being obtained using CO2 transmission data centered at 2.8 micrometers and from a single instrument that uses the limb solar occultation measurement geometry, which provides significant advantages for the calibration of its single profiles.

  5. Long-term air temperature variation in the Karkonosze mountains according to atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Migała, Krzysztof; Urban, Grzegorz; Tomczyński, Karol

    2016-07-01

    The results of meteorological measurements carried out continuously on Mt Śnieżka in Karkonosze mountains since 1880 well document the warming observed on a global scale. Data analysis indicates warming expressed by an increase in the mean annual air temperature of 0.8 °C/100 years. A much higher temperature increase was recorded in the last two decades at the turn of the twenty-first century. Mean decade air temperatures increased from -0.1 to 1.5 °C. It has been shown that there are relationships between air temperature at Mt Śnieżka and global mechanisms of atmospheric and oceanic circulation. Thermal conditions of the Karkonosze (Mt Śnieżka) accurately reflect global climate trends and impact of the North Atlantic Oscillation (NAO) index, macrotypes of atmospheric circulation in Europe (GWL) and Atlantic Multidecadal Oscillation (AMO). The increase in air temperature during the 1989-2012 solar magnetic cycle may reveal a synergy effect to which astrophysical effects and atmospheric and oceanic circulation effects contribute, modified by constantly increasing anthropogenic factors.

  6. Long-term Variations in the Microwave Brightness Temperature of the Uranus Atmosphere

    NASA Astrophysics Data System (ADS)

    Klein, M. J.; Hofstadter, M. D.; Hammel, H. B.; Leflang, J. G.; Roller, J. P.; McLeod, R. K.

    2002-09-01

    Uranus' appearance is changing as its 2007 equinox approaches. Latitudinal banding and discrete cloud features are reported at visible wavelengths and evidence of aerosol variability in the upper atmosphere has been reported in the near-IR. At radio wavelengths, the south pole has appeared brighter than lower latitudes. Microwave observations probe the ~5 to ~50 bar region of the atmosphere, well below the cloud tops. Changes in microwave brightness temperature with time and wavelength are expected to provide insights into seasonal processes affecting the planet's deep atmosphere. Here we report observations of changes in Uranus' 3.5-cm microwave brightness temperature using NASA's Deep Space Network (DSN) antennas at Goldstone, California. Twelve observing "campaigns" from 1984 through 2002 with the 70-m diameter antenna indicate that Uranus' brightness temperature declined from a maximum of ~255 +/- 10 K (circa 1984-86) to ~200 +/- 8 K in 2002. The ``2002 Campaign" is primarily being carried out by middle-school and high-school students from classrooms across the nation. The students and their teachers are participants in the Goldstone-Apple Valley Radio Telescope (GAVRT) science education project, which is a partnership involving NASA, JPL and the Lewis Center for Educational Research in Apple Valley, CA. Working with the Lewis Center over the Internet, GAVRT students conduct remotely controlled radio astronomy observations using 34-m antennas at Goldstone. Their data are validated by professional scientists and incorporated into the data base. We intend to observe Uranus for several years and to coordinate our work with observers at visible and infrared wavelengths and the Very Large Array. The objective is to develop a comprehensive description of the troposphere and improve dynamical models of the planet. The JPL contribution to this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National

  7. Long term monitoring of methane in the atmosphere by multiplex gas chromatography

    NASA Technical Reports Server (NTRS)

    Valentin, Jose R.; Carle, Glenn C.; Phillips, John B.

    1985-01-01

    Methane is of interest in the study of the Earth's atmosphere because of its implication in the future global warming of the surface. This warming is produced by the absorption of infrared energy by trace gases. It has been estimated that in the next 40 to 50 years, methane could contribute 20 to 25 pct. as much atmospheric warming as that expected from carbon dioxide increases. Studies to examine sources, sinks, and cycles of methane will require analytical methods capable of continuous unattended measurement with temporal resolution of an hour or less for weeks at a time. Gas chromatography (GC) is one of the most practical methods available to conduct the analysis of air, but limitations in this technique still exist which can be alleviated with multiplex GC (MGC). MGC is a technique where many samples are pseudo-randomly introduced to the chromatograph without regard to the length of time required for an analysis. The resulting data must then be reduced using computational methods such as cross correlation. In the technique reported, a tube packed with silver oxide was used at the inlet of the GC column to create concentration pulses of methane in a sample stream of air. By using only one carrier, i.e., ambient air, an effective and accurate method to monitor the variations in concentration of methane in the atmosphere over long periods of time was developed. Methane in ambient air was monitored for an eight day period and an interesting temporal variability was found. This work has shown the utility of a relatively simple MGC for the analysis of a real environmental sample.

  8. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet (Sq) daily variation

    NASA Astrophysics Data System (ADS)

    Shinbori, A.; Koyama, Y.; Yatagai, A. I.; Nose, M.; Hori, T.; Otsuka, Y.

    2012-12-01

    activity dependence on the Sq amplitude, we calculated second orders of fitting curve between the F10.7 flux and Sq amplitude during 1950-2011, and examined the residual Sq amplitude defined as the deviation from the fitting curve. The residual Sq amplitude clearly shows increase and decrease trends with the periods of 20 years. Then, it seems that the trends in the residual Sq and Sqp fields are related to the long-term variation in the ionospheric conductivities associated with the secular variation of the ambient magnetic field and the upper atmosphere (for example, plasma and neutral densities). In order to verify qualitatively the above signatures, we need to investigate the long-term variation in the ionospheric conductivities using a calculation tool developed by the IUGONET project.

  9. The Nature of Martian Dust Storms as Revealed by Long Term Daily Global Atmospheric Imaging

    NASA Astrophysics Data System (ADS)

    Wang, H.; Richardson, M. I.

    2013-12-01

    The Martian dust cycle is composed of dust lifting and transport events that span a very wide spectrum of temporal and spatial scales. The largest storm events occur with sufficiently low frequency that we are only beginning to be able to provide an observational baseline for these events after seven Martian years of roughly continuous global atmospheric imaging. Creation of daily global maps from Mars Orbiter Camera (MOC) and Wide Angle and Mars Color Imager (MARCI) images allows the occurrence, evolutionary pathway and development style of large dust storms to be examined in detail. For the period of observations with Thermal Emission Spectrometer (TES) or Mars Climate Sounder (MCS), we can also examine commensurate changes in atmospheric opacity, temperature and crudely track those in surface dust cover (for TES). These observations allow us to construct a "climatology" of large dust storms, which shows distinct families of dust storm types on the basis of the season and location of storm origin, replacing prior simplified descriptions of a single "dust storm season". We are also able to describe common transport and evolutionary pathways for storms, including very different behaviors of storms originating in the northern versus the southern mid- and high-latitudes. For some of the larger storms during Mars Years 24-26, we are also able to show how the storms modified the surface dust cover, and on what time scales and by what processes the surface dust distribution "recovers" to pre-storm conditions. The results from MOC and MARCI suggest that we have only just begun to collect enough data for a statistically-meaningful climatology of regional-scale storms, and that substantially longer time series would be needed to understanding the diversity and nature of the very largest, global-scale storms. A planned successor for MARCI is greatly needed for our prospects of adequately understanding these dust storm systems, not only for the current and past climate

  10. Fine mode aerosol composition at three long-term atmospheric monitoring sites in the Amazon Basin

    SciTech Connect

    Artaxo, P.; Gerab, F.; Yamasoe, M.A.; Martins, J.V.

    1994-11-01

    The Amazon Basin tropical rain forest is a key region to study processes that are changing the composition of the global atmosphere, including the large amount of fine mode aerosol particles emitted during biomass burning that might influence the global atmosphere. Three background monitoring stations, Alta Floresta, Cuiaba, and Serra do Navio, are operating continuously measuring aerosol composition. Fine (particle diameter less than 2.0 microns) and coarse (particle diameter greater than 2.0 microns and less than 10 microns) mode aerosol particles were collected using stacked filter units. Particle-induced X-ray emission was used to measure concentrations of up to 20 elements in the fine mode: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, and Pb. Soot carbon and gravimetric mass analysis were also performed. Absolute Principal Factor Analysis (APFA) has derived absolute elemental source profiles. APFA showed four aerosol particle components: soil dust (Al, Ca, Ti, Mn, Fe), biomass burning (soot, fine mode mass concentration, K, Cl), natural primary biogenic particles with gas-to-particle component (K, S, Ca, Mn, Zn), and marine aerosol (Cl). Biogenic and biomass burning aerosol particles dominate the fine mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and fine mode mass concentration (FPM). At the Alta Floresta and Cuiaba sites, during the dry season, a strong component of biomass burning is observed. Inhalable particulate matter (particle diameter less than 10 microns) mass concentration up to 700 micrograms/cu m was measured. Fine particle mass concentration alone can go as high as 400 micrograms/cu m for large regions.

  11. WRF-HMS, a fully-coupled regional atmospheric-hydrological modeling system for long-term scale applications

    NASA Astrophysics Data System (ADS)

    Wagner, Sven; Fersch, Benjamin; Yuan, Fei; Yu, Zhongbo; Kunstmann, Harald

    2016-04-01

    Feedback among the atmosphere, land surface and subsurface is important to understand the non-linear connections within the hydrological cycle. Investigations of climate and land-use changes on the regional water balance require fully-coupled atmospheric-hydrological modeling systems, which describe such feedback mechanisms and allow long-term simulations at climate-relevant scales. We have developed such a fully-coupled, meso-scale modeling system extending the atmospheric model WRF-ARW with the hydrological model HMS, which includes lateral water fluxes at the land surface and subsurface. Both models are bound to the Noah land surface model (Noah-LSM) and share compatible water and energy flux formulations. In addition, two-way interaction between the saturated and the unsaturated zone is implemented by replacing the free drainage bottom boundary of the Noah-LSM with two approaches, a Fixed-head boundary condition assuming an equilibrium soil moisture distribution or a Darcy-flux at the boundary assuming a quasi-steady-state moisture profile below the LSM. The comparatively small additional computational demand of this coupled model system allows long-term simulations. A first application of the fully-coupled modeling system was performed for the Poyang Lake basin (160,000 km²) in Southern China for the years 1979-1986. For the WRF model, a double-nesting approach is applied covering East Asia at 30 km resolution and the Poyang Lake basin at 10 km using ERA Interim data as global forcing. The HMS and fully-coupled simulations are performed on the 10 km grid. The performance of the stand-alone and the fully coupled simulations are presented. Furthermore, the impact of groundwater coupling on soil moisture, evapotranspiration, temperature and precipitation is investigated.

  12. Long-Term Atmospheric Changes Caused by the Very Large Solar Proton Event in July 2000

    NASA Technical Reports Server (NTRS)

    Jackman, C. H.; Marsh, D. R.; Garcia, R. R.; Vitt, F. M.; Randall, C. E.; Fleming, F. L.; Labow, G. J.

    2007-01-01

    Solar cycle 23 was accompanied by eight very large solar proton events (SPEs) between 2000 and 2005, along with numerous smaller events. The very large SPE in July 2000, which was associated with the well-known 'Bastille Day Solar Storm,' caused very substantial changes in the polar mesosphere and stratosphere. Significant downward transport of the SPE-produced NO(x) from the polar lower mesosphere and upper stratosphere during the Southern Hemisphere winter period resulted in huge enhancements (>100%) in middle stratospheric NO(x) (NO+NO2) during September 2000 in the polar vortex, which were measured by UARS HALOE (C. E. Randall et al., Geophys. Res. Lett., 28,2385-2388,2001). We have used the Whole Atmosphere Community Climate Model (WACCM) to study the longer-term impact of the July 2000 SPE, the third largest SPE period in the past 40 years. This very large SPE provided a wonderful opportunity to study the downward transport of energetic particle precipitation effects in the middle atmosphere. Not surprisingly, the WACCM-simulated polar Northern Hemisphere influences from the July (mid-summer) 2000 SPE were significant for a few months, but the constituent changes were not transported below about 20 hPa. However in the polar Southern Hemisphere (SH) region, the persistent downward transport in the vortex during the months of July-August-September resulted in significant modeled influences for about a year past the SPE. The SH odd nitrogen family, NO(y) (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2), was greatly enhanced by this SPE and these increases were transported to the lower stratosphere. The SPE-enhanced polar NO(y) resulted in long-lasting ozone decreases (from catalytic NO(y) destruction of ozone) and ozone increases (from NO(y) interference in the chlorine and bromine catalytic ozone destruction cycles). These ozone changes resulted in simulated SH polar stratospheric temperature decreases (1-2 K) and increases (1-3 K)..

  13. Long Term Atmospheric and Erosional Pollution As Recorded in Lake Sediments from Yunnan, China

    NASA Astrophysics Data System (ADS)

    Hillman, A. L.; Abbott, M. B.; Yu, J.; Bain, D.; Chiou-Peng, T.

    2014-12-01

    Human activities including agriculture, metallurgy (e.g. mining, processing, smelting), and deforestation have altered cycles of erosion and sedimentation in lake environments for thousands of years. In the Yunnan province of southwestern China, where written records are incomplete, it is unclear when, where, and how much disturbance occurred. Lake sediments offer a means to investigate a wide variety of human activities. Here, we present a lake sediment record from Erhai (25°43'N, 100°12'E) based on trace metal concentrations that reveals substantial atmospheric and erosional pollution to the lake environment over the last 4,000 years. Sediments indicate the initiation of copper-based metallurgy at 3,600 years BP, the existence of which has been debated amongst archaeologists. Beginning 2,000 years BP, sedimentation rates increase and concentrations of metals such as aluminum, titanium, lead, and zinc increase. This is likely linked to increased sediment flux to the lake associated with the initiation of terraced agriculture according to historical documents. The most prominent feature of the record is an abrupt and intense increase in lead, silver, cadmium, and zinc beginning at 700 years BP. The peak of this increase occurs at 600 years BP and is consistent with historical records that the Mongols established the first government operated silver mine in Yunnan. Notably, the concentrations of lead during this time are an order of magnitude greater than modern day levels of pollution.

  14. Implications of solar irradiance variability upon long-term changes in the Earth's atmospheric temperatures

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III

    1992-01-01

    From 1979 through 1987, it is believed that variability in the incoming solar energy played a significant role in changing the Earth's climate. Using high-precision spacecraft radiometric measurements, the incoming total solar irradiance (total amount of solar power per unit area) and the Earth's mean, global atmospheric temperatures were found to vary in phase with each other. The observed irradiance and temperature changes appeared to be correlated with the 11-year cycle of solar magnetic activity. During the period from 1979 through 1985, both the irradiance and temperature decreased. From 1985 to 1987, they increased. The irradiance changed approximately 0.1 percent, while the temperature varied as much as 0.6 C. During the 1979-1987 period, the temperatures were forecasted to rise linearly because of the anthropogenic build-up of carbon dioxide and the hypothesized 'global warming', 'greenhouse effect', scenarios. Contrary to these scenarios, the temperatures were found to vary in a periodic manner in phase with the solar irradiance changes. The observed correlations between irradiance and temperature variabilily suggest that the mean, global temperature of the Earth may decline between 1990 and 1997 as solar magnetic activity decreases.

  15. Long-term determination of energetic electron precipitation into the atmosphere from AARDDVARK subionospheric VLF observations

    NASA Astrophysics Data System (ADS)

    Neal, Jason J.; Rodger, Craig J.; Clilverd, Mark A.; Thomson, Neil R.; Raita, Tero; Ulich, Thomas

    2015-03-01

    We analyze observations of subionospherically propagating very low frequency (VLF) radio waves to determine outer radiation belt energetic electron precipitation (EEP) flux magnitudes. The radio wave receiver in Sodankylä, Finland (Sodankylä Geophysical Observatory) observes signals from the transmitter with call sign NAA (Cutler, Maine). The receiver is part of the Antarctic-Arctic Radiation-belt Dynamic Deposition VLF Atmospheric Research Konsortia (AARDDVARK). We use a near-continuous data set spanning November 2004 until December 2013 to determine the long time period EEP variations. We determine quiet day curves over the entire period and use these to identify propagation disturbances caused by EEP. Long Wave Propagation Code radio wave propagation modeling is used to estimate the precipitating electron flux magnitudes from the observed amplitude disturbances, allowing for solar cycle changes in the ambient D region and dynamic variations in the EEP energy spectra. Our method performs well during the summer months when the daylit ionosphere is most stable but fails during the winter. From the summer observations, we have obtained 693 days worth of hourly EEP flux magnitudes over the 2004-2013 period. These AARDDVARK-based fluxes agree well with independent satellite precipitation measurements during high-intensity events. However, our method of EEP detection is 10-50 times more sensitive to low flux levels than the satellite measurements. Our EEP variations also show good agreement with the variation in lower band chorus wave powers, providing some confidence that chorus is the primary driver for the outer belt precipitation we are monitoring.

  16. Long-term variation in the upper atmosphere as seen in the amplitude of the geomagnetic solar quiet daily variation

    NASA Astrophysics Data System (ADS)

    Shinbori, A.; Koyama, Y.; Hayashi, H.; Nose, M.; Hori, T.; Otsuka, Y.; Tsuda, T.

    2011-12-01

    It has been well-known that geomagnetic solar quiet (Sq) daily variation is produced by global ionospheric currents flowing in the E-region from middle latitudes to the magnetic equator. These currents are generated by a dynamo process via interaction between the neutral wind and ionospheric plasma in a region of the thermosphere and ionosphere. From the Ohm's equation, the ionospheric currents strongly depend on the ionospheric conductivity, polarization electric field and neutral wind. Then, to investigate the Sq amplitude is essential for understanding the long-term variations in the ionospheric conductivity and neutral wind of the thermosphere and ionosphere. Elias et al. [2010] found that the Sq amplitude tends to increase by 5.4-9.9 % in the middle latitudes from 1961 to 2001. They mentioned that the long-term variation of ionospheric conductivity associated with geomagnetic secular variation mainly determines the Sq trend, but that the rest component is ionospheric conductivity enhancement associated with cooling effects in the thermosphere due to increasing the greenhouse gases. In this talk, we clarify the characteristics of the long-term variation in the Sq amplitude using the long-term observation data of geomagnetic field and neutral wind. These observation data have been provided by the IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project. In the present analysis, we used the F10.7 flux as an indicator of the variation in the solar irradiance in the EUV and UV range, geomagnetic field data with time resolution of 1 hour. The definition of the Sq amplitude is the difference of the H-component between the maximum and minimum per day when the Kp index is less than 4. As a result, the Sq amplitude at all the stations strongly depends on 11-year solar activity, and tends to enhance more during the high activities (19- and 22- solar cycles) than during the low activity (20-solar cycle). The Fourier spectra of the F10.7 flux and Sq

  17. Effects of plant diversity, N fertilization, and elevated carbon dioxide on grassland soil N cycling in a long-term experiment.

    PubMed

    Mueller, Kevin E; Hobbie, Sarah E; Tilman, David; Reich, Peter B

    2013-04-01

    The effects of global environmental changes on soil nitrogen (N) pools and fluxes have consequences for ecosystem functions such as plant productivity and N retention. In a 13-year grassland experiment, we evaluated how elevated atmospheric carbon dioxide (CO2 ), N fertilization, and plant species richness alter soil N cycling. We focused on soil inorganic N pools, including ammonium and nitrate, and two N fluxes, net N mineralization and net nitrification. In contrast with existing hypotheses, such as progressive N limitation, and with observations from other, often shorter, studies, elevated CO2 had relatively static and small, or insignificant, effects on soil inorganic N pools and fluxes. Nitrogen fertilization had inconsistent effects on soil N transformations, but increased soil nitrate and ammonium concentrations. Plant species richness had increasingly positive effects on soil N transformations over time, likely because in diverse subplots the concentrations of N in roots increased over time. Species richness also had increasingly positive effects on concentrations of ammonium in soil, perhaps because more carbon accumulated in soils of diverse subplots, providing exchange sites for ammonium. By contrast, subplots planted with 16 species had lower soil nitrate concentrations than less diverse subplots, especially when fertilized, probably due to greater N uptake capacity of subplots with 16 species. Monocultures of different plant functional types had distinct effects on N transformations and nitrate concentrations, such that not all monocultures differed from diverse subplots in the same manner. The first few years of data would not have adequately forecast the effects of N fertilization and diversity on soil N cycling in later years; therefore, the dearth of long-term manipulations of plant species richness and N inputs is a hindrance to forecasting the state of the soil N cycle and ecosystem functions in extant plant communities. PMID:23504900

  18. Long-Term Growth of Soybean at Elevated [CO2] Does not Cause Acclimation of Stomatal Conductance Under Fully Open-air Conditions.

    NASA Astrophysics Data System (ADS)

    Leakey, A. D.; Bernacchi, C. J.; Ort, D. R.; Long, S. P.

    2008-12-01

    Accurately predicting plant function and global biogeochemical cycles later this century will be complicated if stomatal conductance (gs) acclimates to growth at elevated [CO2], in the sense of a long-term alteration of the response of gs to [CO2], humidity (h) and/or photosynthetic rate (A). If so, photosynthetic and stomatal models will require parameterization at each growth [CO2] of interest. Photosynthetic acclimation to long-term growth at elevated [CO2] occurs frequently. Acclimation of gs has rarely been examined, even though stomatal density commonly changes with growth [CO2]. Soybean was grown under field conditions at ambient [CO2] (378 μmol mol-1) and elevated [CO2] (552 μmol mol-1) using Free-Air [CO2] Enrichment (FACE). This study tested for stomatal acclimation by parameterizing and validating the widely used Ball et al. model (1987, Progress in Photosynthesis Research, Vol IV, 221-224) with measurements of leaf gas exchange. The dependence of gs on A, h and [CO2] at the leaf surface was unaltered by long-term growth at elevated [CO2]. This suggests that the commonly observed decrease in gs under elevated [CO2] is due entirely to the direct instantaneous effect of [CO2] on gs and that there is no longer-term acclimation of stomatal conductance independent of photosynthetic acclimation. The Ball et al. (1987) model accurately predicted gs for soybean growing under ambient and elevated [CO2] in the field. Model parameters under ambient and elevated [CO2] were indistinguishable, demonstrating that stomatal function under ambient and elevated [CO2] could be modeled without the need for parameterization at each growth [CO2].

  19. Long-term growth of soybean at elevated [CO2] does not cause acclimation of stomatal conductance under fully open-air conditions.

    PubMed

    Leakey, Andrew D B; Bernacchi, Carl J; Ort, Donald R; Long, Stephen P

    2006-09-01

    Accurately predicting plant function and global biogeochemical cycles later in this century will be complicated if stomatal conductance (g(s)) acclimates to growth at elevated [CO(2)], in the sense of a long-term alteration of the response of g(s) to [CO(2)], humidity (h) and/or photosynthetic rate (A). If so, photosynthetic and stomatal models will require parameterization at each growth [CO(2)] of interest. Photosynthetic acclimation to long-term growth at elevated [CO(2)] occurs frequently. Acclimation of g(s) has rarely been examined, even though stomatal density commonly changes with growth [CO(2)]. Soybean was grown under field conditions at ambient [CO(2)] (378 micromol mol(-1)) and elevated [CO(2)] (552 micromol mol(-1)) using free-air [CO(2)] enrichment (FACE). This study tested for stomatal acclimation by parameterizing and validating the widely used Ball et al. model (1987, Progress in Photosynthesis Research, vol IV, 221-224) with measurements of leaf gas exchange. The dependence of g(s) on A, h and [CO(2)] at the leaf surface was unaltered by long-term growth at elevated [CO(2)]. This suggests that the commonly observed decrease in g(s) under elevated [CO(2)] is due entirely to the direct instantaneous effect of [CO(2)] on g(s) and that there is no longer-term acclimation of g(s) independent of photosynthetic acclimation. The model accurately predicted g(s) for soybean growing under ambient and elevated [CO(2)] in the field. Model parameters under ambient and elevated [CO(2)] were indistinguishable, demonstrating that stomatal function under ambient and elevated [CO(2)] could be modelled without the need for parameterization at each growth [CO(2)]. PMID:16913868

  20. The MOPITT instrument as a Prototype for Long-Term Space-Based Atmospheric Measurements in the Anthropocene

    NASA Astrophysics Data System (ADS)

    Drummond, James

    2016-07-01

    One of the major characteristics of the Anthropocene will be changes in all the Earth systems on many timescales. Changes that occur within a generation will be very significant for policy decisions and these will require measurements on corresponding timescales from space-based instruments, but these times are long compared to traditional satellite lifetimes. Whether by luck or by good design there are now a number of satellite missions that are recording data over long time periods. With a single instrument, decadal and longer time series of relevant atmospheric parameters have been achieved and the Measurements Of Pollution In The Troposphere (MOPITT) instrument is one such instrument. Launched on 18th December 1999 on the Terra spacecraft, MOPITT has now completed more than 16 years of operation measuring carbon monoxide (CO) over the planet and the mission continues. It is entirely possible that these measurements will span two decades before completion. MOPITT therefore offers a case study of a very long single-instrument time series, albeit one with challenges because this longevity was not part of the original design criteria: The original design specified about a five year life and this has already been considerably exceeded. MOPITT does enable us to look at long term trends and intermittent phenomena over the planet for an extended period of tie encompassing an entire solar cycle and many cycles of El Niño and other quasi-periodic phenomena. This presentation will consider, with examples, some of the advantages and some of the problems of these long-term space measurements with an eye to the future and the needs of future generations. MOPITT was provided to NASA's Terra spacecraft by the Canadian Space Agency and was built by COMDEV of Cambridge, Ontario. Data processing is performed by the MOPITT team at the National Center for Atmospheric Research, Boulder, CO. Instrument control is by the team at the University of Toronto.

  1. Long Term Monitoring Trends In The Southeastern U.S.: Changes In Atmospheric Chemistry?

    NASA Astrophysics Data System (ADS)

    Blanchard, C. L.; Hidy, G. M.

    2013-12-01

    The SOS/SEARCH network has measured air pollutant concentrations in the southeastern U.S. since 1992, providing context for the 2013 Southeastern Organic Aerosol Study (SOAS). Ambient concentrations and species ratios indicate evolution in atmospheric chemistry. Since 1999, ~50 percent decreases in anthropogenic SOx, NOx, CO, and VOC emissions reduced gas and fine particle concentrations at all SEARCH sites. Primary but not secondary pollutant concentration decreases were approximately proportional to emission declines. Mean annual ambient SO2 mixing ratios at rural SEARCH sites decreased in proportion to annual SO2 emissions, whereas mean annual PM2.5 sulfate (SO4) concentrations decreased until 2009 but then showed minimal change despite continuing SO2 emission reductions. This difference suggests a change in oxidant-SO2 relationships. Between 1999 and 2012, the mean ratios of SO2/SOx (SOx = SO2 + SO4, molar basis) decreased from 0.68 × 0.04 to 0.57 × 0.05 and from 0.73 × 0.05 to 0.59 × 0.05 at two rural sites, indicating changes in SO4 production. Mean annual mixing ratios of oxidized nitrogen species (NOy) at rural sites decreased from 5.8 × 1.9 ppbv in 1992 to 4.8 × 1.4 ppbv in 2002 and 2.4 × 0.5 ppbv in 2012, proportional to NOx emission changes. Mean annual afternoon (noon through 4 p.m.) ratios of NOz/NOy (NOz = NOy - NOx) at rural sites varied between 0.36 and 0.63 from 1997 to 2011, without showing trends. Mean afternoon O3/NOy ratios increased at both urban and non-urban sites, e.g., from 8.3 × 0.4 in 1992 to 11.5 × 0.5 in 1999 and 19.9 × 0.9 in 2011 in rural Alabama, and from 2.0 × 0.1 in 1999 to 4.9 × 0.3 in 2011 in Atlanta, suggesting increased oxidation rates. Regression of daily peak 8-hour O3 against afternoon NOz yielded slopes ranging from urban 4.02 × 0.15 to rural 11.32 × 0.42, reflecting higher O3 production efficiency (OPE) at rural compared to urban sites. The OPE exhibited year-to-year variability with increasing trends at

  2. Long-term clinical outcome of ST-segment elevation myocardial infarction patients with and without diabetes mellitus in the Zwolle trial

    PubMed Central

    Timmer, J.R.; van der Horst, I.C.C.; Henriques, J.P.S.; Thomas, K.; Bilo, H.J.G.; Hoorntje, J.C.A.; de Boer, M.J.; Suryapranata, H.; Zijlstra, F.

    2003-01-01

    Objectives We sought to compare long-term survival after ST-segment elevation myocardial infarction (STEMI) in patients with and without diabetes mellitus (DM) treated with primary percutaneous coronary intervention (PCI) or thrombolytic therapy. Background DM is an adverse prognostic factor after STEMI. However, there is only limited information about long-term clinical outcome in STEMI patients with DM treated with PCI or thrombolysis. Methods Patients with STEMI (n=395) were randomised to treatment either with intravenous streptokinase or PCI. Mean follow-up was 8±2 years. We studied long-term mortality of patients with DM (n=32) and without DM (n=363) and the interaction with the treatment regimen. Results After eight years, a total of 17 patients with DM (53%) died compared with 88 (24%) patients without DM (OR 3.5, p<0.001). Reduced left ventricular ejection fraction (LVEF) after STEMI was more often present in patients with DM compared with patients without DM (31% vs. 15%, p=0.01). Multivariate analysis revealed that DM (OR 2.6, 95% CI 1.4-4.7, p=0.002), reduced LVEF (OR 2.4, 95% CI 1.5-3.8, p<0.001) and age ≥60 years (OR 2.4, 95% CI 1.5-3.8, p<0.001) were independent risk factors for long-term mortality. Patients with DM treated with PCI had less LVEF (13% vs. 53%, p=0.01) and lower long-term mortality rates (38% vs. 69%, p=0.08) compared with treatment with thrombolysis. Conclusions STEMI patients with DM are a high-risk group with higher long-term mortality rates compared with patients without DM. PCI is the treatment of choice, particularly in DM patients. PMID:25696147

  3. SHORT- AND LONG-TERM EFFECTS OF ELEVATED CO2 ON PHOTOSYNTHESIS AND RESPIRATION IN THE MARINE MACROALGA HIZIKIA FUSIFORMIS (SARGASSACEAE, PHAEOPHYTA) GROWN AT LOW AND HIGH N SUPPLIES(1).

    PubMed

    Zou, Dinghui; Gao, Kunshan; Luo, Hanjin

    2011-02-01

    The short-term and long-term effects of elevated CO2 on photosynthesis and respiration were examined in cultures of the marine brown macroalga Hizikia fusiformis (Harv.) Okamura grown under ambient (375 μL · L(-1) ) and elevated (700 μL · L(-1) ) CO2 concentrations and at low and high N availability. Short-term exposure to CO2 enrichment stimulated photosynthesis, and this stimulation was maintained with prolonged growth at elevated CO2 , regardless of the N levels in culture, indicating no down-regulation of photosynthesis with prolonged growth at elevated CO2 . However, the photosynthetic rate of low-N-grown H. fusiformis was more responsive to CO2 enrichment than that of high-N-grown algae. Elevation of CO2 concentration increased the value of K1/2 (Ci) (the half-saturation constant) for photosynthesis, whereas high N supply lowered it. Neither short-term nor long-term CO2 enrichment had inhibitory effects on respiration rate, irrespective of the N supply, under which the algae were grown. Under high-N growth, the Q10 value of respiration was higher in the elevated-CO2 -grown algae than the ambient-CO2 -grown algae. Either short- or long-term exposure to CO2 enrichment decreased respiration as a proportion of gross photosynthesis (Pg) in low-N-grown H. fusiformis. It was proposed that in a future world of higher atmospheric CO2 concentration and simultaneous coastal eutrophication, the respiratory carbon flux would be more sensitive to changing temperature. PMID:27021713

  4. 25 Years of Variability in the Biology of Salix-feeding Beetles and Associated Insects Along a Sierra Nevada Elevation Gradient, California: Are There Long-term Trends?

    NASA Astrophysics Data System (ADS)

    Smiley, J. T.; Rank, N. E.; Dahlhoff, E.

    2006-12-01

    We have been studying the ecology, evolution and physiology of the willow leaf beetle, Chrysomela aeneicollis, in the Eastern Sierra Nevada Mountains, California, since the early 1980's. One principal focus of this long-term study has been analysis of elevation gradient effects to the food web which includes willows (Salix ssp.), C. aeneicollis, and several predators including the hover fly Parasyphus melanderi and the hole-nesting wasp Symmorphus cristatus. We have observed and documented asymmetries along the elevation gradient. At upper elevations, populations confront higher frequencies of lethally cold nighttime temperatures and intensity of storms. When individuals are transplanted among elevations, upper elevation populations grow faster and survive better at upper elevation sites than populations from lower elevations. Our observations suggest that dispersal is sufficiently restricted among elevations to allow genetic differences in ability to respond to stressful climate to emerge. Lower elevation populations are subject to a wider range of predatory insect species, and predation plays a relatively larger role in their reproductive success. We have documented upward shifts in range for some populations of about 300 meters over the 25-year period of the study, although other populations do not show such shifts. We are preparing to document further range shifts along the elevation gradients by monitoring habitats which are currently at or above the upper range limits of the plants, beetles and predators, and looking for recruitment of new populations at those sites.

  5. Chemical and anatomical changes in Liquidambar styraciflua L. xylem after long term exposure to elevated CO2.

    PubMed

    Kim, Keonhee; Labbé, Nicole; Warren, Jeffrey M; Elder, Thomas; Rials, Timothy G

    2015-03-01

    The anatomical and chemical characteristics of sweetgum were studied after 11 years of elevated CO2 (544 ppm, ambient at 391 ppm) exposure. Anatomically, branch xylem cells were larger for elevated CO2 trees, and the cell wall thickness was thinner. Chemically, elevated CO2 exposure did not impact the structural components of the stem wood, but non-structural components were significantly affected. Principal component analysis (PCA) was employed to detect differences between the CO2 treatments by considering numerous structural and chemical variables, as well as tree size, and data from previously published sources (i.e., root biomass, production and turnover). The PCA results indicated a clear separation between trees exposed to ambient and elevated CO2 conditions. Correlation loadings plots of the PCA revealed that stem structural components, ash, Ca, Mg, total phenolics, root biomass, production and turnover were the major responses that contribute to the separation between the elevated and ambient CO2 treated trees. PMID:25603157

  6. INTERCOMPARISON STUDY OF ATMOSPHERIC MERCURY MODELS: 2. MODELING RESULTS VS. LONG-TERM OBSERVATIONS AND COMPARISON OF COUNTRY ATMOSPHERIC BALANCES

    EPA Science Inventory

    Five regional scale models with a horizontal domain covering the European continent and its surrounding seas, two hemispheric and one global scale model participated in the atmospheric Hg modelling intercomparison study. The models were compared between each other and with availa...

  7. Variability in the intraspecific response of Pinus ponderosa seedlings subjected to long-term exposure to elevated CO{sub 2}

    SciTech Connect

    Houpis, J.L.J.; Anschel, D.J.; Pushnik, J.C.; Anderson, P.D.

    1995-01-01

    The authors are investigating the effects of elevated CO{sub 2} and intraspecific variability on Pinus ponderosa. To analyze intraspecific variability, they included seedling source (family) as an additional treatment, using a split-plot experimental design. The three elevated CO{sub 2} treatments were ambient (approx. 350 ppm CO{sub 2}), ambient + 175 ppm CO{sub 2} and ambient +350 ppm CO{sub 2}. Their study uses the source/sink control framework at several key integrating steps, incorporating the long-term effects of elevated CO{sub 2} (insuring sufficient time for the expression of any long-term physiological and biochemical acclimation to occur) and genetics (using multiple species and multiple known genetic sources) in an attempt to ascertain the extent of overall regulation contributed by selected independent regulatory process at the physiological, biochemical and structural level. In order to assess intraspecific variability, this paper reports on the integration of measurements of photosynthesis, chlorophyll fluorescence, pigmentation, RuBPCase, SPSase to quantify the effects of elevated CO{sub 2} on the growth response of various families of the same species.

  8. DOES SOIL CO2 EFFLUX ACCLIMATIZETO ELEVATED TEMPERATURE AND CO2 DURING LONG-TERM TREATMENT OF DOUGLAS-FIR SEEDLINGS?

    EPA Science Inventory

    We investigated the effects of elevated soil temperature and atmospheric CO2 efflux (SCE) during the third an fourth years of study. We hypothesized that elevated temperature would stimulate SCE, and elevated CO2 would also stimulate SCE with the stimulation being greater at hig...

  9. Long-Term, Autonomous Measurement of Atmospheric Carbon Dioxide Using an Ormosil Nanocomposite-Based Optical Sensor

    SciTech Connect

    Kisholoy Goswami

    2005-10-11

    The goal of this project is to construct a prototype carbon dioxide sensor that can be commercialized to offer a low-cost, autonomous instrument for long-term, unattended measurements. Currently, a cost-effective CO2 sensor system is not available that can perform cross-platform measurements (ground-based or airborne platforms such as balloon and unmanned aerial vehicle (UAV)) for understanding the carbon sequestration phenomenon. The CO2 sensor would support the research objectives of DOE-sponsored programs such as AmeriFlux and the North American Carbon Program (NACP). Global energy consumption is projected to rise 60% over the next 20 years and use of oil is projected to increase by approximately 40%. The combustion of coal, oil, and natural gas has increased carbon emissions globally from 1.6 billion tons in 1950 to 6.3 billion tons in 2000. This figure is expected to reach 10 billon tons by 2020. It is important to understand the fate of this excess CO2 in the global carbon cycle. The overall goal of the project is to develop an accurate and reliable optical sensor for monitoring carbon dioxide autonomously at least for one year at a point remote from the actual CO2 release site. In Phase I of this project, InnoSense LLC (ISL) demonstrated the feasibility of an ormosil-monolith based Autonomous Sensor for Atmospheric CO2 (ASAC) device. All of the Phase I objectives were successfully met.

  10. Long-term measurements of atmospheric point-spread functions over littoral waters as determined by atmospheric turbulence

    NASA Astrophysics Data System (ADS)

    de Jong, Arie N.; Schwering, Piet B. W.; Benoist, Koen W.; Gunter, Willem H.; Vrahimis, George; October, Faith J.

    2012-06-01

    During the FATMOSE trial, held over the False Bay, South Africa) from November 2009 until October 2010, day and night (24/7) high resolution images were collected of point sources at a range of 15.7 km. Simultaneously, data were collected on atmospheric parameters, as relevant for the turbulence conditions: air- and sea temperature, windspeed, relative humidity and the structure parameter for refractive index: Cn 2. The data provide statistical information on the mean value and the variance of the atmospheric point spread function and the associated modulation transfer function during series of consecutive frames. This information allows the prediction of the range performance for a given sensor, target and atmospheric condition, which is of great importance for the user of optical sensors in related operational areas and for the developers of image processing algorithms. In addition the occurrence of "lucky shots" in series of frames is investigated: occasional frames with locally small blur spots. The simultaneously measured short exposure blur and the beam wander are compared with simultaneously collected scintillation data along the same path and the Cn 2 data from a locally installed scintillometer. By using two vertically separated sources, the correlation is determined between the beam wander in their images, providing information on the spatial extension of the atmospheric turbulence (eddy size). Examples are shown of the appearance of the blur spot, including skewness and astigmatism effects, which manifest themselves in the third moment of the spot and its distortion. An example is given of an experiment for determining the range performance for a given camera and a bar target on an outgoing boat in the False Bay.

  11. Chemical and anatomical changes in Liquidambar styraciflua L. xylem after long term exposure to elevated CO2

    SciTech Connect

    Kim, Keonhee; Labbé, Nicole; Warren, Jeffrey M.; Elder, Thomas; Rials, Timothy G.

    2015-01-17

    The anatomical and chemical characteristics of sweetgum were studied after 11 years of elevated CO2 (544 ppm, ambient at 391 ppm) exposure. Anatomically, branch xylem cells were larger for elevated CO2 trees, and the cell wall thickness was thinner. Chemically, elevated CO2 exposure did not impact the structural components of the stem wood, but non-structural components were significantly affected. Principal component analysis (PCA) was employed to detect differences between the CO2 treatments by considering numerous structural and chemical variables, as well as tree size, and data from previously published sources (for example, root biomass, production and turnover). The PCA results indicated a clear separation between trees exposed to ambient and elevated CO2 conditions. Lastly, correlation loadings plots of the PCA revealed that stem structural components, ash, Ca, Mg, total phenolics, root biomass, production and turnover were the major responses that contribute to the separation between the elevated and ambient CO2 treated trees.

  12. Chemical and anatomical changes in Liquidambar styraciflua L. xylem after long term exposure to elevated CO2

    DOE PAGESBeta

    Kim, Keonhee; Labbé, Nicole; Warren, Jeffrey M.; Elder, Thomas; Rials, Timothy G.

    2015-01-17

    The anatomical and chemical characteristics of sweetgum were studied after 11 years of elevated CO2 (544 ppm, ambient at 391 ppm) exposure. Anatomically, branch xylem cells were larger for elevated CO2 trees, and the cell wall thickness was thinner. Chemically, elevated CO2 exposure did not impact the structural components of the stem wood, but non-structural components were significantly affected. Principal component analysis (PCA) was employed to detect differences between the CO2 treatments by considering numerous structural and chemical variables, as well as tree size, and data from previously published sources (for example, root biomass, production and turnover). The PCA resultsmore » indicated a clear separation between trees exposed to ambient and elevated CO2 conditions. Lastly, correlation loadings plots of the PCA revealed that stem structural components, ash, Ca, Mg, total phenolics, root biomass, production and turnover were the major responses that contribute to the separation between the elevated and ambient CO2 treated trees.« less

  13. Physiological and phenological bases of decline in growth enhancement after long-term exposure to elevated CO[sub 2

    SciTech Connect

    Miao, S.L.; Bazzaa, F.A. )

    1994-06-01

    We addressed the degree to which CO[sub 2]-induced growth enhancement in six temperate deciduous tree species is sustained, the physiological and phenological bases that underlie the growth response, and the effects of naturally occurring resource heterogeneity on seedling and sampling response to CO[sub 2] after three years of growth. At the end of year three, CO[sub 2]-induced growth enhancements decline with different degree among species and resource treatments. Photosynthetic rates as a function of intercellular CO[sub 2] concentrations were greatly influenced by elevated CO[sub 2], nutrients, light, and species. High CO[sub 2] plants, however, showed higher photosynthetic rates than ambient CO[sub 2] plants when both groups were measured in CO[sub 2] concentrations in situ. The photosynthetic enhancement is elevated CO[sub 2] largely resulted from higher intercellular CO[sub 2] levels. In contrast to photosynthesis, stomatal conductance showed little variation. The effect of elevated CO[sub 2] on leaf phenology was species-specific. In gray birch and yellow birch, ambient CO[sub 2] plants had lower leaf bud mortality and a faster rate of leaf bud break than high CO[sub 2] plants. In contrast, in red maple and striped maple, elevated CO[sub 2] plants showed lower leaf bud mortality in some treatments and there was no statistical difference in leaf bud break between ambient and elevated CO[sub 2] plants. These results show that beneficial effects of higher photosynthetic rates on growth in a high CO[sub 2] environment may be negated in some species by changes in other plant traits. Differential responses of species to elevated CO[sub 2] may have important implications for forest regeneration and species composition.

  14. Serial Multifocal Electroretinograms during Long-term Elevation and Reduction of Intraocular Pressure in Non-human Primates

    PubMed Central

    Nork, T. Michael; Kim, Charlene B. Y.; Heatley, Gregg A.; Kaufman, Paul L.; Lucarelli, Mark J.; Levin, Leonard A.; Ver Hoeve, James N.

    2010-01-01

    The purpose of this study was to evaluate the relationship between elevations of intraocular pressure (IOP) and the multifocal electroretinogram (mfERG) in non-human primates. Experimental glaucoma was induced in 4 rhesus and 4 cynomolgus monkeys by laser trabecular meshwork destruction (LTD) in one eye. To evaluate the contribution of ganglion cells to mfERG changes, one monkey of each species had previously underwent unilateral optic nerve transection (ONT). After ≥ 44 weeks of elevation, the IOP was reduced by trabeculectomy in 2 non-transected animals. In the intact (non-transected) animals there was an increase in the amplitude of the early mfERG waveforms (N1 and P1) of the first order kernel (K1) throughout the period of IOP elevation in all of the rhesus, but not all of the cynomolgus monkeys. A species difference was also present as a decrease of the second order kernel, first slice (K2.1) in all of the cynomolgus monkeys but only in 1 of the rhesus monkeys (the 1 with the ONT). Similar IOP effects on the mfERG were seen in the ONT animals. Surgical lowering of IOP resulted in a return of the elevated K1 amplitudes to baseline levels. However, the depressed K2.1 RMS in the cynomolgus monkeys did not recover. These results demonstrate species-specific changes in cone-driven retinal function during periods of elevated IOP. These IOP-related effects can occur in the absence of retinal ganglion cells and may be reversible. PMID:20422254

  15. Long-Term Clinical Outcomes according to Initial Management and Thrombolysis In Myocardial Infarction Risk Score in Patients with Acute Non-ST-Segment Elevation Myocardial Infarction

    PubMed Central

    Jeong, Hae Chang; Jeong, Myung Ho; Chae, Shung Chull; Hur, Seung Ho; Hong, Taek Jong; Kim, Young Jo; Seong, In Whan; Chae, Jei Keon; Rhew, Jay Young; Chae, In Ho; Cho, Myeong Chan; Bae, Jang Ho; Rha, Seung Woon; Kim, Chong Jin; Choi, Donghoon; Jang, Yang Soo; Yoon, Junghan; Chung, Wook Sung; Cho, Jeong Gwan; Seung, Ki Bae; Park, Seung Jung

    2010-01-01

    Purpose There is still debate about the timing of revascularization in patients with acute non-ST-segment elevation myocardial infarction (NSTEMI). We analyzed the long-term clinical outcomes of the timing of revascularization in patients with acute NSTEMI obtained from the Korea Acute Myocardial Infarction Registry (KAMIR). Materials and Methods 2,845 patients with acute NSTEMI (65.6 ± 12.5 years, 1,836 males) who were enrolled in KAMIR were included in the present study. The therapeutic strategy of NSTEMI was categorized into early invasive (within 48 hours, 65.8 ± 12.6 years, 856 males) and late invasive treatment (65.3 ± 12.1 years, 979 males). The initial- and long-term clinical outcomes were compared between two groups according to the level of Thrombolysis In Myocardial Infarction (TIMI) risk score. Results There were significant differences in-hospital mortality and the incidence of major adverse cardiac events during one-year clinical follow-up between two groups (2.1% vs. 4.8%, p < 0.001, 10.0% vs. 13.5%, p = 0.004, respectively). According to the TIMI risk score, there was no significant difference of long-term clinical outcomes in patients with low to moderate TIMI risk score, but significant difference in patients with high TIMI risk score (≥ 5 points). Conclusions The old age, high Killip class, low ejection fraction, high TIMI risk score, and late invasive treatment strategy are the independent predictors for the long-term clinical outcomes in patients with NSTEMI. PMID:20046515

  16. Effect of mountain climatic elevation gradient and litter origin on decomposition processes: long-term experiment with litter-bags

    NASA Astrophysics Data System (ADS)

    Klimek, Beata; Niklińska, Maria; Chodak, Marcin

    2013-04-01

    Temperature is one of the most important factors affecting soil organic matter decomposition. Mountain areas with vertical gradients of temperature and precipitation provide an opportunity to observe climate changes similar to those observed at various latitudes and may serve as an approximation for climatic changes. The aim of the study was to compare the effects of climatic conditions and initial properties of litter on decomposition processes and thermal sensitivity of forest litter. The litter was collected at three altitudes (600, 900, 1200 m a.s.l.) in the Beskidy Mts (southern Poland), put into litter-bags and exposed in the field since autumn 2011. The litter collected at single altitude was exposed at the altitude it was taken and also at the two other altitudes. The litter-bags were laid out on five mountains, treated as replicates. Starting on April 2012, single sets of litter-bags were collected every five weeks. The laboratory measurements included determination of dry mass loss and chemical composition (Corg, Nt, St, Mg, Ca, Na, K, Cu, Zn) of the litter. In the additional litter-bag sets, taken in spring and autumn 2012, microbial properties were measured. To determine the effect of litter properties and climatic conditions of elevation sites on decomposing litter thermal sensitivity the respiration rate of litter was measured at 5°C, 15°C and 25°C and calculated as Q10 L and Q10 H (ratios of respiration rate between 5° and 15°C and between 15°C and 25°C, respectively). The functional diversity of soil microbes was measured with Biolog® ECO plates, structural diversity with phospholipid fatty acids (PLFA). Litter mass lost during first year of incubation was characterized by high variability and mean mass lost ranged up to a 30% of initial mass. After autumn sampling we showed, that mean respiration rate of litter (dry mass) from the 600m a.s.l site exposed on 600m a.s.l. was the highest at each tested temperature. In turn, the lowest mean

  17. The detection and interpretation of long-term atmospheric change: Tasks in association with the shuttle solar backscatter ultraviolet spectral radiometer

    NASA Technical Reports Server (NTRS)

    Frederick, John E.

    1987-01-01

    The objectives are to develop techniques to detect and remove long-term instrument drifts from the operational Solar Backscatter Ultraviolet (SBUV/2) data base using periodic measurements made by the Shuttle Solar Backscatter Ultraviolet Spectral Radiometer and to evaluate the potential effects of scattering by atmospheric aerosols on our ability to detect trends in ozone using SBUV-class instruments.

  18. Maintenance of C sinks sustains enhanced C assimilation during long-term exposure to elevated [CO2] in Mojave Desert shrubs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the first few years of elevated atmospheric [CO2] treatment at the Nevada Desert FACE Facility, photosynthetic downregulation was observed in desert shrubs grown under elevated [CO2], especially under relatively wet environmental conditions. Nonetheless, those plants maintained increased Asat...

  19. Effects of Long-Term Thermal Exposure on Commercially Pure Titanium Grade 2 Elevated-Temperature Tensile Properties

    NASA Technical Reports Server (NTRS)

    Ellis, David L.

    2012-01-01

    Elevated-temperature tensile testing of commercially pure titanium (CP Ti) Grade 2 was conducted for as-received commercially produced sheet and following thermal exposure at 550 and 650 K (531 and 711 F) for times up to 5000 h. The tensile testing revealed some statistical differences between the 11 thermal treatments, but most thermal treatments were statistically equivalent. Previous data from room temperature tensile testing was combined with the new data to allow regression and development of mathematical models relating tensile properties to temperature and thermal exposure. The results indicate that thermal exposure temperature has a very small effect, whereas the thermal exposure duration has no statistically significant effects on the tensile properties. These results indicate that CP Ti Grade 2 will be thermally stable and suitable for long-duration space missions.

  20. Climate data by elevation in the Great Smoky Mountains: a database and graphical displays for 1947 - 1950 with comparison to long-term data

    USGS Publications Warehouse

    Busing, Richard T.; Stephens, Luther A.; Clebsch, Edward E.C.

    2004-01-01

    A climate data set is presented for four sites spanning the elevation gradient in the Great Smoky Mountains from Gatlinburg to Clingmans Dome. Monthly mean values for cloud cover, temperature, humidity, precipitation, and soil moisture are included. Stephens (1969) is the source of all summarized mean monthly data. Values are the averages of four years (1947-1950) with moderate to high precipitation. Graphical displays show strong climatic patterns of variation among seasons and elevations. The upper stations had lower temperatures and higher precipitation totals; however, temperature lapse rates and variation in vapor pressure deficits decreased at upper elevations. To examine how well the four-year sample represents the long-term climate, temperature and precipitation for the Gatlinburg (1460 ft elevation at park headquarters) station were compared between the years in the sample and the years in the full record from 1928 to 2003. Trends related to season and elevation are consistent with earlier studies and provide a basis for interpretation of climate dynamics in the southern Appalachian Mountains.

  1. Emiliania huxleyi increases calcification but not expression of calcification-related genes in long-term exposure to elevated temperature and pCO2

    PubMed Central

    Benner, Ina; Diner, Rachel E.; Lefebvre, Stephane C.; Li, Dian; Komada, Tomoko; Carpenter, Edward J.; Stillman, Jonathon H.

    2013-01-01

    Increased atmospheric pCO2 is expected to render future oceans warmer and more acidic than they are at present. Calcifying organisms such as coccolithophores that fix and export carbon into the deep sea provide feedbacks to increasing atmospheric pCO2. Acclimation experiments suggest negative effects of warming and acidification on coccolithophore calcification, but the ability of these organisms to adapt to future environmental conditions is not well understood. Here, we tested the combined effect of pCO2 and temperature on the coccolithophore Emiliania huxleyi over more than 700 generations. Cells increased inorganic carbon content and calcification rate under warm and acidified conditions compared with ambient conditions, whereas organic carbon content and primary production did not show any change. In contrast to findings from short-term experiments, our results suggest that long-term acclimation or adaptation could change, or even reverse, negative calcification responses in E. huxleyi and its feedback to the global carbon cycle. Genome-wide profiles of gene expression using RNA-seq revealed that genes thought to be essential for calcification are not those that are most strongly differentially expressed under long-term exposure to future ocean conditions. Rather, differentially expressed genes observed here represent new targets to study responses to ocean acidification and warming. PMID:23980248

  2. Long-term performance of ceramic matrix composites at elevated temperatures: Modelling of creep and creep rupture

    SciTech Connect

    Curtin, W.A.; Fabeny, B.; Ibnabdeljalil, M.; Iyengar, N.; Reifsnider, K.L.

    1996-07-31

    The models developed, contain explicit dependences on constituent material properties and their changes with time, so that composite performance can be predicted. Three critical processes in ceramic composites at elevated temperatures have been modeled: (1) creep deformation of composite vs stress and time-dependent creep of fibers and matrix, and failure of these components; (2) creep deformation of ``interface`` around broken fibers; and (3) lifetime of the composite under conditions of fiber strength loss over time at temperature. In (1), general evolution formulas are derived for relaxation time of matrix stresses and steady-state creep rate of composite; the model is tested against recent data on Ti-MMCs. Calculations on a composite of Hi-Nicalon fibers in a melt-infiltrated SiC matrix are presented. In (2), numerical simulations of composite failure were made to map out time-to-failure vs applied load for several sets of material parameters. In (3), simple approximate relations are obtained between fiber life and composite life that should be useful for fiber developers and testers. Strength degradation data on Hi-Nicalon fibers is used to assess composite lifetime vs fiber lifetime for Hi-Nicalon fiber composites.

  3. Long-term continuous allopregnanolone elevation causes memory decline and hippocampus shrinkage, in female wild-type B6 mice.

    PubMed

    Bengtsson, Sara K S; Johansson, Maja; Bäckström, Torbjörn

    2016-02-01

    Chronic stress in various forms increases the risk for cognitive dysfunction, dementia and Alzheimer's disease. While the pathogenesis behind these findings is unknown, growing evidence suggests that chronic increase in neurosteroid levels, such as allopregnanolone, is part of the mechanism. We treated wild-type C57BL/6J mice with allopregnanolone for 5months, using osmotic pumps. This treatment led to moderately increased levels of allopregnanolone, equivalent to that of mild chronic stress. After an interval of no treatment for 1month, female mice showed impaired learning and memory function in the Morris water maze (MWM) in combination with diminished hippocampus weight and increased cerebellum weight, both correlating to MWM performance. Male mice showed a minor reduction in memory function and no differences in brain structure. We conclude that chronic allopregnanolone elevation can lead to cognitive dysfunction and negative brain alterations. We suggest that allopregnanolone could play a key role in the pathogenesis of stress-induced cognitive disturbances and perhaps dementia. PMID:26497250

  4. Impact of Mean Platelet Volume on Long-Term Mortality in Chinese Patients with ST-Elevation Myocardial Infarction

    PubMed Central

    Sun, Xi-peng; Li, Bo-yu; Li, Jing; Zhu, Wei-wei; Hua, Qi

    2016-01-01

    We investigated the association between mean platelet volume (MPV) and risk of all-cause mortality in Chinese patients with ST-Elevation Myocardial Infarction (STEMI). We enrolled 1836 patients with STEMI in Xuanwu Hospital from January 2008 to December 2013. Based on MPV, patients were categorized into the following groups: <9.5 fL (n = 85), 9.5–11.0 fL (n = 776), 11.1–12.5 fL (n = 811) and >12.5 fL (n = 164), respectively. Mean duration of follow-up was 56.9 months, and 197 patients (10.7%) died during follow-up. All-cause mortality rates were compared between groups. The lowest mortality occurred in patients with MPV between 9.5–11.0 fL, with a multivariable-adjusted hazard ratio (HR) of 1.15(95%CI 0.62–1.50), 1.38(95%CI 1.20–1.68), and 1.72(95%CI 1.41–1.96) in patients with MPV of <.5, 11.1–12.5 and >12.5 fL, respectively. Therefore, increased MPV was associated with all-cause mortality in Chinese patients with STEMI. MPV might be useful as a marker for risk stratification in Chinese patients with STEMI. PMID:26879002

  5. Modern and long-term evaporation of central Andes surface waters suggests paleo archives underestimate Neogene elevations

    NASA Astrophysics Data System (ADS)

    Fiorella, Richard P.; Poulsen, Christopher J.; Pillco Zolá, Ramiro S.; Jeffery, M. Louise; Ehlers, Todd A.

    2015-12-01

    Central Andean paleoelevations reconstructed from stable isotope and paleofloral data imply a large magnitude (>2 km) Miocene-to-modern surface uplift. However, the isotopic relationships between precipitation, surface waters, and soil waters upon which these reconstructions are based remain poorly constrained for both past, and in many cases, modern conditions. We quantify the relationships between central Andean precipitation and surface waters by measuring the isotopic composition of 249 stream water samples (δ18O and δD) collected between April 2009 and October 2012. The isotopic compositions of stream waters match precipitation along the eastern flank. In contrast, Altiplano surface waters possess a lower δD-δ18O slope (4.59 vs ∼8 for meteoric waters) not observed in precipitation, which signals heavy isotope evaporative enrichment in surface waters. Paleoclimate models indicate that highly evaporative conditions have persisted on the plateau throughout Andean uplift, and that conditions may have been more evaporative when the Andes were lower. Thus, more ancient proxy materials may have a greater evaporative bias than previously recognized and paleoelevation reconstructions from stable isotope based central Andean plateau proxy materials likely overstate Miocene-to-present surface uplift. We propose Altiplano paleoelevations of 1-2 km at 24.5 Ma, 1.5-2.9 km by 11.45 Ma, and modern elevations by ∼6 Ma based on the lightest isotopic compositions observed in Altiplano proxy materials, which are least likely to be influenced by evaporation. These constraints limit total late-Miocene-to-modern uplift to <2.2 km, are more consistent with crustal shortening records, and suggest that plateau uplift may have been more spatially uniform than suggested by previous interpretations of stable isotope proxies.

  6. Impact of long-term moderate hypercapnia and elevated temperature on the energy budget of isolated gills of Atlantic cod (Gadus morhua).

    PubMed

    Kreiss, Cornelia M; Michael, Katharina; Bock, Christian; Lucassen, Magnus; Pörtner, Hans-O

    2015-04-01

    Effects of severe hypercapnia have been extensively studied in marine fishes, while knowledge on the impacts of moderately elevated CO2 levels and their combination with warming is scarce. Here we investigate ion regulation mechanisms and energy budget in gills from Atlantic cod acclimated long-term to elevated PCO2 levels (2500 μatm) and temperature (18°C). Isolated perfused gill preparations were established to determine gill thermal plasticity during acute exposures (10-22°C) and in vivo costs of Na(+)/K(+)-ATPase activity, protein and RNA synthesis. Maximum enzyme capacities of F1Fo-ATPase, H(+)-ATPase and Na(+)/K(+)-ATPase were measured in vitro in crude gill homogenates. After whole animal acclimation to elevated PCO2 and/or warming, branchial oxygen consumption responded more strongly to acute temperature change. The fractions of gill respiration allocated to protein and RNA synthesis remained unchanged. In gills of fish CO2-exposed at both temperatures, energy turnover associated with Na(+)/K(+)-ATPase activity was reduced by 30% below rates of control fish. This contrasted in vitro capacities of Na(+)/K(+)-ATPase, which remained unchanged under elevated CO2 at 10°C, and earlier studies which had found a strong upregulation under severe hypercapnia. F1Fo-ATPase capacities increased in hypercapnic gills at both temperatures, whereas Na(+)/K(+)ATPase and H(+)-ATPase capacities only increased in response to elevated CO2 and warming indicating the absence of thermal compensation under CO2. We conclude that in vivo ion regulatory energy demand is lowered under moderately elevated CO2 levels despite the stronger thermal response of total gill respiration and the upregulation of F1Fo-ATPase. This effect is maintained at elevated temperature. PMID:25535111

  7. Source portioning of N_{2}O emissions after long term elevation of soil temperature in a permanent grassland soil

    NASA Astrophysics Data System (ADS)

    Jansen-Willems, Anne; Lanigan, Gary; Clough, Timothy; Andresen, Louise; Müller, Christoph

    2016-04-01

    Several methods, such as source portioning, have been used to quantify the contributions of individual N pools to N2O emissions. These methods however, assume the absence of hybrid reactions such as co-denitrification, which were previously identified as important. A straight forward method portioning N2O fluxes into four different production processes, including a hybrid reaction, was therefore developed. This method portioned the N2O fluxes in nitrification, denitrification, oxidation of organic matter and co-denitrification, using data on 45R and 46R of the N2O flux and the 15N content of the NO3‑ and NH4+ in the soil. This newly developed method was used to analyse the N2O emissions from incubated soil, which was previously subjected to 6 years of elevated soil temperature of +0, +1, +2 or +3 ° C. N2O emissions were measured and analysed at four time points in the six days following, NO315NH4 Gly or 15NO3NH4 Gly, label addition. The oxidation of organic N was found to be the main source of N2O fluxes at all sampling dates, comprising between 63 and 85% of the total N2O flux. The percentage contribution made by organic N to N2O fluxes increased over the sampling period, rising from a minimum of 40% in the control treatment, to virtually 100% across all treatments by Day 6. Compared to the control treatment, denitrification contributed less to N2O from soil subjected to +2 and +3 ° C warming (p <0.0001 and p=0.002, respectively). Co-denitrification only contributed to the N2O flux during the first day after substrate addition. The highest amount of N2O produced via co-denitrification was found under the control treatment. From soil subjected to +2 and +3 ° C treatments, the contribution of co-denitrification was minor. However, these differences in co-denitrification were not significant. This research showed the importance of the oxidation of organic N in N2O emissions. It should therefore not be omitted as a potential source in source portioning. Emissions

  8. Separating long-term deformation cycles and atmospheric signals at Mount St. Helens using PS-InSAR

    NASA Astrophysics Data System (ADS)

    Welch, M.

    2015-12-01

    Since its eruption in 1980, Mount St. Helens has experienced multiple inflation-deflation cycles associated with dome building eruptions. During the most recent dome-building episode, which spanned 2004 to 2008, GPS recorded the transition from pre-eruptive inflation to co-eruptive deflation and a final transition back to inflation. Such observations provide important constraints on the timing and mechanics of cyclic magma recharge and extrusion. Currently, the subtle surface deformation signal at St Helens is monitored primarily by ground based geodetic techniques like GPS. Satellite-based InSAR has the potential to substantially augment these techniques by providing spatially continuous, precise measurements of surface displacements, and may also reveal other volcanic or surficial processes too localized to be detected by ground based methods. Traditional interferometry is challenging to apply to volcanoes in the Cascades. Widespread phase decorrelation caused by persistent snow cover and dense vegetation, combined with large, elevation dependent atmospheric phase delays, mask or make deformation signals difficult to detect. By applying StaMPS, a Persistent Scatterers (PS) technique, phase decorrelation is mitigated by utilizing only the pixels with the highest, statistically derived, signal to noise ratio. However, atmospheric water vapor, which delays the radar signal, remains problematic, particularly on the volcano edifice. To assess the bias imposed by the atmosphere, we perform a series of sensitivity tests using a suite of methods including several that rely on the linear or power-law correlation of phase delay to topography and knowledge of the spatial scale of the signal. We also apply methods that calculate wet and dry phase delay from atmospheric reanalysis datasets such as ERA-Interim provided by the ECMWF. SAR data from the ERS, Envisat, and ALOS satellites, along with newer datasets, are processed with these tools to create a time series spanning

  9. Is fire a long term sink or source of atmospheric carbon? A comprehensive evaluation of a boreal forest fire

    NASA Astrophysics Data System (ADS)

    Santin, C.; Doerr, S. H.; Preston, C.; Bryant, R.

    2012-12-01

    -fire fuel assessment, ii) fire behaviour monitoring and iii) immediate post-fire fuel and PyC inventory. Before the fire, fuel characteristics were established and the site was instrumented with auto-logging thermocouples to provide temperature-duration profiles during burning. Also, different types of PyC were placed on the ground to determine PyC loss during the fire. Immediately after fire, the various post-burn PyC products and stores were sampled. Total PyC was quantified and the chemical recalcitrance of the different PyC forms found was determined. The results obtained will be discussed in the context of PyC production, and its different forms and quantities, with respect to (i) fire characteristics and fuel consumed, and (ii) the long term carbon balance in this boreal forest environment for recurring fire-regrowth cycles under current and predicted future climatic conditions.

  10. Long-term clinical results of autologous bone marrow CD 133+ cell transplantation in patients with ST-elevation myocardial infarction

    NASA Astrophysics Data System (ADS)

    Kirgizova, M. A.; Suslova, T. E.; Markov, V. A.; Karpov, R. S.; Ryabov, V. V.

    2015-11-01

    The aim of the study was investigate the long-term results of autologous bone marrow CD 133+ cell transplantation in patients with primary ST-Elevation Myocardial Infarction (STEMI). Methods and results: From 2006 to 2007, 26 patients with primary STEMI were included in an open randomized study. Patients were randomized to two groups: 1st - included patients underwent PCI and transplantation of autologous bone marrow CD 133+ cell (n = 10); 2nd - patients with only PCI (n = 16). Follow-up study was performed 7.70±0.42 years after STEMI and consisted in physical examination, 6-min walking test, Echo exam. Total and cardiovascular mortality in group 1 was lower (20% (n = 2) vs. 44% (n = 7), p = 0.1 and 22% (n = 2) vs. 25% (n = 4), (p=0.53), respectively). Analysis of cardiac volumetric parameters shows significant differences between groups: EDV of 100.7 ± 50.2 mL vs. 144.40±42.7 mL, ESV of 56.3 ± 37.8 mL vs. 89.7 ± 38.7 mL in 1st and 2nd groups, respectively. Data of the study showed positive effects of autologous bone marrow CD 133+ cell transplantation on the long-term survival of patients and structural status of the heart.

  11. A weighted relative difference accumulation algorithm for dynamic metabolomics data: long-term elevated bile acids are risk factors for hepatocellular carcinoma

    PubMed Central

    Zhang, Weijian; Zhou, Lina; Yin, Peiyuan; Wang, Jinbing; Lu, Xin; Wang, Xiaomei; Chen, Jianguo; Lin, Xiaohui; Xu, Guowang

    2015-01-01

    Dynamic metabolomics studies can provide a systematic view of the metabolic trajectory during disease development and drug treatment and reveal the nature of biological processes at metabolic level. To extract important information in a systematic time dimension rather than at isolated time points, a weighted method based on the means and variations along the time points was proposed and first applied to previously published rat model data. The method was subsequently extended and applied to prospective metabolomics data analysis of hepatocellular carcinoma (HCC). Permutation was employed for noise filtering and false discovery rate (FDR) was used for parameter optimization during the feature selection. Long-term elevated serum bile acids were identified as risk factors for HCC development. PMID:25757957

  12. Long-Term Care

    MedlinePlus

    ... this page please turn Javascript on. Long-Term Care What Is Long-Term Care? Long-term care involves a variety of services ... the Escape (Esc) button on your keyboard.) Most Care Provided at Home Long-term care is provided ...

  13. Nitrogen and carbon cycling in a grassland community ecosystem as affected by elevated atmospheric CO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing global atmospheric CO2 concentration has led to concerns regarding its potential effects on terrestrial ecosystem and the long-term storage of C and N in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L.) Willd (...

  14. Modeling long-term uptake and re-volatilization of semi-volatile organic compounds (SVOCs) across the soil-atmosphere interface.

    PubMed

    Bao, Zhongwen; Haberer, Christina; Maier, Uli; Beckingham, Barbara; Amos, Richard T; Grathwohl, Peter

    2015-12-15

    Soil-atmosphere exchange is important for the environmental fate and atmospheric transport of many semi-volatile organic compounds (SVOCs). This study focuses on modeling the vapor phase exchange of semi-volatile hydrophobic organic pollutants between soil and the atmosphere using the multicomponent reactive transport code MIN3P. MIN3P is typically applied to simulate aqueous and vapor phase transport and reaction processes in the subsurface. We extended the code to also include an atmospheric boundary layer where eddy diffusion takes place. The relevant processes and parameters affecting soil-atmosphere exchange were investigated in several 1-D model scenarios and at various time scales (from years to centuries). Phenanthrene was chosen as a model compound, but results apply for other hydrophobic organic compounds as well. Gaseous phenanthrene was assumed to be constantly supplied to the system during a pollution period and a subsequent regulation period (with a 50% decline in the emission rate). Our results indicate that long-term soil-atmosphere exchange of phenanthrene is controlled by the soil compartment - re-volatilization thus depends on soil properties. A sensitivity analysis showed that accumulation and transport in soils in the short term is dominated by diffusion, whereas in the long term groundwater recharge and biodegradation become relevant. As expected, sorption causes retardation and slows down transport and biodegradation. If atmospheric concentration is reduced (e.g. after environmental regulations), re-volatilization from soil to the atmosphere occurs only for a relatively short time period. Therefore, the model results demonstrate that soils generally are sinks for atmospheric pollutants. The atmospheric boundary layer is only relevant for time scales of less than one month. The extended MIN3P code can also be applied to simulate fluctuating concentrations in the atmosphere, for instance due to temperature changes in the topsoil. PMID:26340582

  15. Admission Lipoprotein-Associated Phospholipase A2 Activity Is Not Associated with Long-Term Clinical Outcomes after ST-Segment Elevation Myocardial Infarction

    PubMed Central

    Woudstra, Pier; Damman, Peter; Kuijt, Wichert J.; Kikkert, Wouter J.; Grundeken, Maik J.; van Brussel, Peter M.; Stroobants, An K.; van Straalen, Jan P.; Fischer, Johan C.; Koch, Karel T.; Henriques, José P. S.; Piek, Jan J.; Tijssen, Jan G. P.; de Winter, Robbert J.

    2014-01-01

    Background Lipoprotein-associated phospholipase A2 (Lp-PLA2) activity is a biomarker predicting cardiovascular diseases in a real-world. However, the prognostic value in patients undergoing primary percutaneous coronary intervention (pPCI) for ST-segment elevation myocardial infarction (STEMI) on long-term clinical outcomes is unknown. Methods Lp-PLA2 activity was measured in samples obtained prior to pPCI from consecutive STEMI patients in a high-volume intervention center from 2005 until 2007. Five years all-cause mortality was estimated with the Kaplan-Meier method and compared among tertiles of Lp-PLA2 activity during complete follow-up and with a landmark at 30 days. In a subpopulation clinical endpoints were assessed at three years. The prognostic value of Lp-PLA2, in addition to the Thrombolysis In Myocardial Infarction or multimarker risk score, was assessed in multivariable Cox regression. Results The cohort (n = 987) was divided into tertiles (low <144, intermediate 144–179, and high >179 nmol/min/mL). Among the tertiles differences in baseline characteristics associated with long-term mortality were observed. However, no significant differences in five years mortality in association with Lp-PLA2 activity levels were found; intermediate versus low Lp-PLA2 (HR 0.97; CI 95% 0.68–1.40; p = 0.88) or high versus low Lp-PLA2 (HR 0.75; CI 95% 0.51–1.11; p = 0.15). Both in a landmark analysis and after adjustments for the established risk scores and selection of cases with biomarkers obtained, non-significant differences among the tertiles were observed. In the subpopulation no significant differences in clinical endpoints were observed among the tertiles. Conclusion Lp-PLA2 activity levels at admission prior to pPCI in STEMI patients are not associated with the incidence of short and/or long-term clinical endpoints. Lp-PLA2 as an independent and clinically useful biomarker in the risk stratification of STEMI patients still remains to be proven

  16. Effects of Long-Term Daily Administration of Prostaglandin-E2 on Maintaining Elevated Proximal Tibial Metaphyseal Cancellous Bone Mass in Male Rats

    NASA Technical Reports Server (NTRS)

    Ke, Hua Zhu; Jee, Webster S. S.; Mori, Satoshi; Li, Xiao Jian; Kimmel, Donald B.

    1992-01-01

    The effects of long-term prostaglandin E(sub 2) (PGE(sub 2)) on cancellous bone in proximal tibial metaphysis were studied in 7 month old male Sprague-Dawley rats given daily subcutaneous injections of 0, 1, 3, and 6 mg PGE(sub 2)/kg/day and sacrificed after 60, 120, and 180 days. Histomorphometric analyses were performed on double fluorescent-labeled undecalcified bone specimens. After 60 days of treatment, PGE(sub 2) produced diffusely labeled trabecular bone area, increased trabecular bone area, eroded and labeled trabecular perimeter, mineral apposition rate, and bone formation rate at all dose levels when compared with age-matched controls. In rats given PGE(sub 2) for longer time periods (120 and 180 days), trabecular bone area, diffusely labeled trabecular bone area, labeled perimeter, mineral apposition, and bone formation rates were sustained at the elevated levels achieved earlier at 60-day treatment. The eroded perimeter continued to increase until 120 days, then plateau. The observation that continuous systemic PGE(sub 2) administration to adult male rats elevated metaphyseal cancellous bone mass to 3.5-fold of the control level within 60 days and maintained it for another 120 days indicates that the powerful skeletal anabolic effects of PGE2 can be sustained with continuous administration .

  17. Rapid and long-term effects of water deficit on gas exchange and hydraulic conductance of silver birch trees grown under varying atmospheric humidity

    PubMed Central

    2014-01-01

    Background Effects of water deficit on plant water status, gas exchange and hydraulic conductance were investigated in Betula pendula under artificially manipulated air humidity in Eastern Estonia. The study was aimed to broaden an understanding of the ability of trees to acclimate with the increasing atmospheric humidity predicted for northern Europe. Rapidly-induced water deficit was imposed by dehydrating cut branches in open-air conditions; long-term water deficit was generated by seasonal drought. Results The rapid water deficit quantified by leaf (ΨL) and branch water potentials (ΨB) had a significant (P < 0.001) effect on gas exchange parameters, while inclusion of ΨB in models resulted in a considerably better fit than those including ΨL, which supports the idea that stomatal openness is regulated to prevent stem rather than leaf xylem dysfunction. Under moderate water deficit (ΨL≥-1.55 MPa), leaf conductance to water vapour (gL), transpiration rate and leaf hydraulic conductance (KL) were higher (P < 0.05) and leaf temperature lower in trees grown in elevated air humidity (H treatment) than in control trees (C treatment). Under severe water deficit (ΨL<-1.55 MPa), the treatments showed no difference. The humidification manipulation influenced most of the studied characteristics, while the effect was to a great extent realized through changes in soil water availability, i.e. due to higher soil water potential in H treatment. Two functional characteristics (gL, KL) exhibited higher (P < 0.05) sensitivity to water deficit in trees grown under increased air humidity. Conclusions The experiment supported the hypothesis that physiological traits in trees acclimated to higher air humidity exhibit higher sensitivity to rapid water deficit with respect to two characteristics - leaf conductance to water vapour and leaf hydraulic conductance. Disproportionate changes in sensitivity of stomatal versus leaf hydraulic conductance to water deficit

  18. Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation

    NASA Astrophysics Data System (ADS)

    Shinbori, Atsuki; Koyama, Yukinobu; Nose, Masahito; Hori, Tomoaki; Otsuka, Yuichi; Yatagai, Akiyo

    2014-12-01

    Characteristics of long-term variation in the amplitude of solar quiet (Sq) geomagnetic field daily variation have been investigated using 1-h geomagnetic field data obtained from 69 geomagnetic observation stations within the period of 1947 to 2013. The Sq amplitude observed at these geomagnetic stations showed a clear dependence on the 10- to 12-year solar activity cycle and tended to be enhanced during each solar maximum phase. The Sq amplitude was the smallest around the minimum of solar cycle 23/24 in 2008 to 2009. The relationship between the solar F10.7 index and Sq amplitude was approximately linear but about 53% of geomagnetic stations showed a weak nonlinear relation to the solar F10.7 index. In order to remove the effect of solar activity seen in the long-term variation of the Sq amplitude, we calculated a linear or second-order fitting curve between the solar F10.7 index and Sq amplitude during 1947 to 2013 and examined the residual Sq amplitude, which is defined as the deviation from the fitting curve. As a result, the majority of trends in the residual Sq amplitude that passed through a trend test showed negative values over a wide region. This tendency was relatively strong in Europe, India, the eastern part of Canada, and New Zealand. The relationship between the magnetic field intensity at 100-km altitude and residual Sq amplitude showed an anti-correlation for about 71% of the geomagnetic stations. Furthermore, the residual Sq amplitude at the equatorial station (Addis Ababa) was anti-correlated with the absolute value of the magnetic field inclination. This implies movement of the equatorial electrojet due to the secular variation of the ambient magnetic field.

  19. Long-Term cosmic ray experiment in the atmosphere: Energetic electron precipitation events during the 20-23 solar activity cycles.

    NASA Astrophysics Data System (ADS)

    Makhmutov, V. S.; Bazilevskaya, G. A.; Krainev, M. B.; Storini, M.

    2001-08-01

    More than 400 energetic electron precipitation events (EPEs) were observed in the Earth's Northern polar atmosphere (Murmansk region, 68°57'N, 33°03'E) during a long-term cosmic ray balloon experiment (from 1957 up to now). It is shown that the significant X-ray fluxes, caused by precipitating electrons at the top of the atmosphere, sometimes penetrated down to the atmospheric depth of ~60 g· cm-2 (about 20 km). It means that primary energy of precipitating electrons was more than ~ 6 10 MeV. Here we summarize only the characteristics of the energetic electron precipitation events recorded during solar activity cycles 20 to 23. We dis cuss results from the analyses of the interplanetary and geomagnetic conditions related to these events in the atmosphere.

  20. Long-Term Estrogen Deprivation Leads to Elevation of Dickkopf-1 and Dysregulation of Wnt/ -Catenin Signaling in Hippocampal CA1 Neurons

    PubMed Central

    Scott, Erin L.; Zhang, Quan-guang; Han, Dong; Desai, Bhavna N.; Brann, Darrell W.

    2012-01-01

    Surgically menopausal women incur a 2–5 fold increased risk for dementia and mortality from neurological diseases, but the mechanisms underlying these increased risks remain unclear. Previously, we demonstrated that after global cerebral ischemia (GCI), 17β-estradiol (E2 or estrogen) suppresses hippocampal elevation of the Wnt antagonist Dickkopf-1 (Dkk1), a neurodegenerative factor. We, thus, hypothesized that prolonged loss of E2 may lead to dysregulation of neural Dkk1 and Wnt/β-Catenin signaling, which could contribute to an increased risk of neurodegeneration. To test this hypothesis, we examined the effect of shortterm (1 week - STED) and long-term E2 deprivation (10 weeks - LTED) via ovariectomy upon basal and E2-regulated Dkk1 levels and Wnt/β-Catenin signaling in the hippocampal CA1 region following GCI. In STED rats, E2 exerted robust neuroprotection against GCI, suppressed postischemic elevation of Dkk1, and enhanced pro-survival Wnt/β-Catenin signaling, effects that were lost in LTED rats. Intriguingly, LTED rats displayed modest basal changes in Dkk1 and survivin expression. Further work showed that c-Jun N-Terminal Kinase (JNK) mediated GCI-induced changes in Dkk1 and survivin, and JNK inhibition afforded neuroprotection in LTED rats. Finally, we extended our findings to natural aging, as 24-month-old, reproductively senescent female rats also displayed a modest increase in basal Dkk1 in the CA1, which consistently co-localized with the apoptotic marker TUNEL after GCI and coincided with a loss of E2 neuroprotection. As a whole, this study supports the “critical period hypothesis” and further suggests that perimenopausal estradiol replacement may prevent neurodegenerative changes in the hippocampus by maintaining favorable Wnt/β-Catenin signaling. PMID:23178162

  1. Does long-term elevation of CO{sub 2} concentration increase photosynthesis in forest floor vegetation? Indiana strawberry in a Maryland forest

    SciTech Connect

    Osborne, C.P.; Long, S.P.; Drake, B.G.

    1997-05-01

    As the partial pressure of CO{sub 2} (pCO{sub 2}) in the atmosphere rises, photorespiratory loss of carbon in C, photosynthesis will diminish and the net efficiency of light-limited photosynthetic carbon uptake should rise. Indiana strawberry (Duchesnea indica) growing on a Maryland forest floor was tested. Open-top chambers were used to elevate the pCO{sub 2} of a forest floor habitat to 67 Pa and were paired with control chambers with an ambient pCO{sub 2} of 38 Pa. After 3.5 years, D. indica leaves in the elevated pCO{sub 2} showed a significantly greater maximum quantum efficiency of net photosynthesis (by 22%) and a lower light compensation point (by 42%) than leaves in the control chambers. The quantum efficiency to minimize photorespiration was the same for controls and plants grown at elevated pCO{sub 2}, showing the maximum efficiency of light-energy transduction into assimilated carbon was not altered by acclimation and the increase in light-limited photosynthesis at elevated pCO{sub 2} was a function of the decrease in photorespiration. Acclimation did decrease the ribulose-1,5-bisphosphate carboxylase/oxygenase and light-harvesting chlorophyll protein content of the leaf by more than 30%. These changes were associated with a decreased capacity for light-saturated, but not light-limited, photosynthesis. Leaves of D. indica grown and measured at elevated pCO{sub 2} showed greater light-saturated photosynthetic rates than leaves grown and measured at the current atmospheric pCO{sub 2}. In situ measurements under natural lighting showed large increases in leaf photosynthesis at elevated pCO{sub 2}, relative to controls, in both summer and fall. The increase in efficiency of light-limited photosynthesis with elevated pCO{sub 2} allowed positive net photosynthetic carbon uptake on days and at locations on the forest floor that light fluxes were insufficient for positive net photosynthesis in the current atmospheric pCO{sub 2}. 33 refs., 3 figs., 3 tabs.

  2. Long-term precipitation forecast for drought relief using atmospheric circulation factors: a study on the Maharloo Basin in Iran

    NASA Astrophysics Data System (ADS)

    Sigaroodi, S. K.; Chen, Q.; Ebrahimi, S.; Nazari, A.; Choobin, B.

    2014-05-01

    Long-term precipitation forecasts can help to reduce drought risk through proper management of water resources. This study took the saline Maharloo Lake, which is located in the north of Persian Gulf, southern Iran, and is continuously suffering from drought disaster, as a case to investigate the relationships between climatic indices and precipitation. Cross-correlation in combination with stepwise regression technique was used to determine the best variables among 40 indices and identify the proper time lag between dependent and independent variables for each month. The monthly precipitation was predicted using an artificial neural network (ANN) and multi-regression stepwise methods, and results were compared with observed rainfall data. Initial findings indicated that climate indices such as NAO (North Atlantic Oscillation), PNA (Pacific North America) and El Niño are the main indices to forecast drought in the study area. According to R2, root mean square error (RMSE) and Nash-Sutcliffe efficiency, the ANN model performed better than the multi-regression model, which was also confirmed by classification results. Moreover, the model accuracy to forecast the rare rainfall events in dry months (June to October) was higher than the other months. From the findings it can be concluded that there is a relationship between monthly precipitation anomalies and climatic indices in the previous 10 months in Maharloo Basin. The highest and lowest accuracy of the ANN model were in September and March, respectively. However, these results are subject to some uncertainty due to a coarse data set and high system complexity. Therefore, more research is necessary to further elucidate the relationship between climatic indices and precipitation for drought relief. In this regard, consideration of other climatic and physiographic factors (e.g., wind and physiography) can be helpful.

  3. Long-term variability of CO2 and O in the Mars upper atmosphere from MRO radio science data

    NASA Astrophysics Data System (ADS)

    Genova, Antonio; Goossens, Sander; Lemoine, Frank G.; Mazarico, Erwan; Fricke, Susan K.; Smith, David E.; Zuber, Maria T.

    2015-05-01

    We estimate the annual variability of CO2 and O partial density using approximately 6 years of Mars Reconnaissance Orbiter (MRO) radio science data from August 2006 to January 2012, which cover three full Martian years (from the northern hemisphere summer of 28 to the northern hemisphere summer of 31). These two elements are the dominant species at the MRO periapsis altitude, constituting about 70-80% of the total density. We report the recovered annual cycle of CO2 and the annual and seasonal cycle of O in the upper atmosphere. Although no other observations are available at those altitudes, our results are in good agreement with the density measurements of the Mars Express Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars, which uses stellar occultations between 60 and 130 km to determine the CO2 variability, and with the Mars Global Reference Atmospheric Model 2010 for the O annual and seasonal variabilities. Furthermore, the updated model provides more reasonable MRO drag coefficients (CD), which are estimated to absorb mismodeling in the atmospheric density prediction. The higher content of dust in the atmosphere due to dust storms increases the density, so the CDs should compensate for this effect. The correlation between the drag coefficient and the dust optical depth, measured by the Mars Odyssey Thermal Emission Imaging System (THEMIS) instrument, increases from 0.4 to 0.8 with the a priori and adjusted models, respectively. The trend of CDs not only confirms a substantial improvement in the prediction of the atmospheric density with the updated model but also provides useful information for local dust storms, near MRO periapsis, that cannot be measured by the opacity level since THEMIS does not always sample the southern hemisphere evenly.

  4. Multi-decade Measurements of the Long-Term Trends of Atmospheric Species by High-Spectral-Resolution Infrared Solar Absorption Spectroscopy

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Chiou, Linda; Goldman, Aaron; Hannigan, James W.

    2010-01-01

    Solar absorption spectra were recorded for the first time in 5 years with the McMath Fourier transform spectrometer at the US National solar Observatory on Kitt Peak in southern Arizona, USA (31.91 N latitude, 111.61 W longitude, 2.09 km altitude). The solar absorption spectra cover 750-1300 and 1850-5000 cm(sup -1) and were recorded on 20 days during March-June 2009. The measurements mark the continuation of a long-term record of atmospheric chemical composition measurements that have been used to quantify seasonal cycles and long-term trends of both tropospheric and stratospheric species from observations that began i 1977. Fits to the measured spectra have been performed, and they indicate the spectra obtained since return to operational status are nearly free of channeling and the instrument line shape function is well reproduced taking into account the measurement parameters. We report updated time series measurements of total columns for six atmospheric species and their analysis for seasonal cycles and long-term trends. An sn example, the time series fit shows a decrease in the annual increase rate i Montreal-Protocol-regulated chlorofluorocarbon CCL2F2 from 1.51 plus or minus 0.38% yr(sup -1) at the beginning of the time span to -1.54 plus or minus 1.28 yr(sup -1) at the end of the time span, 1 sigma, and hence provides evidence for the impact of those regulations on the trend.

  5. Building long-term and high spatio-temporal resolution precipitation and air temperature reanalyses by mixing local observations and global atmospheric reanalyses: the ANATEM model

    NASA Astrophysics Data System (ADS)

    Mathevet, T.; Gailhard, J.; Kuentz, A.; Hingray, B.

    2015-12-01

    Efforts to improve the understanding of past climatic or hydrologic variability have received a great deal of attention in various fields of geosciences such as glaciology, dendrochronology, sedimentology and hydrology. Based on different proxies, each research community produces different kinds of climatic or hydrologic reanalyses at different spatio-temporal scales and resolutions. When considering climate or hydrology, many studies have been devoted to characterising variability, trends or breaks using observed time series representing different regions or climates of the world. However, in hydrology, these studies have usually been limited to short temporal scales (mainly a few decades and more rarely a century) because they require observed time series (which suffer from a limited spatio-temporal density). This paper introduces ANATEM, a method that combines local observations and large-scale climatic information (such as the 20CR Reanalysis) to build long-term probabilistic air temperature and precipitation time series with a high spatio-temporal resolution (1 day and a few km2). ANATEM was tested on the reconstruction of air temperature and precipitation time series of 22 watersheds situated in the Durance River basin, in the French Alps. Based on a multi-criteria and multi-scale diagnosis, the results show that ANATEM improves the performance of classical statistical models - especially concerning spatial homogeneity - while providing an original representation of uncertainties which are conditioned by atmospheric circulation patterns. The ANATEM model has been also evaluated for the regional scale against independent long-term time series and was able to capture regional low-frequency variability over more than a century (1883-2010). Citation: Kuentz, A., Mathevet, T., Gailhard, J., and Hingray, B.: Building long-term and high spatio-temporal resolution precipitation and air temperature reanalyses by mixing local observations and global atmospheric

  6. The main results of the long-term measurements of the neutral atmosphere parameters by the artificial periodic irregularities techniques

    NASA Astrophysics Data System (ADS)

    Tolmacheva, Ariadna V.; Bakhmetieva, Nataliya V.; Grigoriev, Gennady I.; Kalinina, Elena E.

    2015-09-01

    The results of the atmospheric parameter determination by the method of artificial periodic irregularities (the API techniques) at the E-region heights obtained during many years of the observation are presented. The features of the obtaining data, their processing and the determination of the atmospheric parameters are given in details. A lot of information about dynamical phenomena in the lower thermosphere has been obtained. There are often height profiles of the atmospheric parameters with the wave-like variations and with the vertical scale of about 4-6 km. The temporal variations of the atmospheric parameters take place with the periods from 15 min to some hours. Such variations could be caused by the passage of the internal gravity waves (IGWs) and the tide waves. The temperature minima were observed as 100-140 K above 100 km in the equinoctial periods. The instability growth is also observed in the number of cases. The dependence of the neutral temperature and the density on solar and geomagnetic activity is not found.

  7. Long-term measurements of atmospheric trace gases (CO2, CH4, N2O, SF6, CO, H2), O2, and δ13CH4 isotopes at Weybourne Atmospheric Observatory, UK: past, present and future

    NASA Astrophysics Data System (ADS)

    Manning, Andrew C.; Forster, Grant L.; Oram, David E.; Reeves, Claire E.; Pickers, Penelope A.; Barningham, S. Thomas; Sturges, William T.; Bandy, Brian; Nisbet, Euan G.; Lowry, David; Fisher, Rebecca; Fleming, Zoe

    2016-04-01

    The Weybourne Atmospheric Observatory (WAO) is situated on the north Norfolk Coast (52.95°N, 1.13°E) in the United Kingdom and is run by the University of East Anglia (UEA), with support from the UK National Centre for Atmospheric Science (NCAS). In 2016, the WAO became a UK-ICOS (Integrated Carbon Observing System) monitoring station. Since 2008, we have been collecting high-precision long-term in situ measurements of atmospheric carbon dioxide (CO2), oxygen (O2), carbon monoxide (CO) and molecular hydrogen (H2), as well as regular bag sampling for δ13CH4. In early 2013, the measurement of atmospheric methane (CH4) commenced, and nitrous oxide (N2O) and sulphur hexafluoride (SF6) began in 2014. We summarise the CO2, O2, CH4, N2O, SF6, CO, H2 and δ13CH4 measurements made to date and highlight some key features observed (e.g. seasonal cycles, long-term trends, pollution events and deposition events). We summarise how the long-term measurements fit into other broader projects which have helped to support the long term time-series at WAO over the years, and highlight how we contribute to broader global atmospheric observation networks.

  8. Outcome of the HORIZONS-AMI trial: bivalirudin enhances long-term survival in patients with ST-elevation myocardial infarction undergoing angioplasty

    PubMed Central

    Shah, Ashish; Feldman, Dmitriy N

    2012-01-01

    setting of primary PCI for STEMI given that its benefits are maintained through long-term follow-up. PMID:22399856

  9. Atmospheric deposition to high-elevation forests

    SciTech Connect

    Lovett, G.M.; Weathers, K.C.; Lindberg, S.E. Oak Ridge National Lab., TN )

    1994-06-01

    Three important phenomena characterize atmospheric deposition to high-elevation forests: (1) multiple deposition mechanisms (wet, dry, and cloud deposition), (2) high rates of deposition, and (3) high spatial variability. The high rates of deposition are caused by changes in meteorological conditions with elevation, especially increasing wind speed and cloud immersion frequency. The high spatial variability of deposition is a result of the regulation of cloud and dry deposition rates by microclimatic and canopy structure conditions, which can be extremely heterogeneous in mountain landscapes. Spruce-fir forests are often [open quotes]hot spots[close quotes] of deposition when viewed in a landscape or regional context because of their elevation, exposure, and evergreen canopy. In this talk we will consider atmospheric depositions to high-elevation forests in both the northeastern and southeastern U.S., using field data and geographic information systems to illustrate deposition patterns.

  10. Increases in the flux of carbon belowground stimulate nitrogen uptake and sustain the long-term enhancement of forest productivity under elevated CO₂.

    PubMed

    Drake, John E; Gallet-Budynek, Anne; Hofmockel, Kirsten S; Bernhardt, Emily S; Billings, Sharon A; Jackson, Robert B; Johnsen, Kurt S; Lichter, John; McCarthy, Heather R; McCormack, M Luke; Moore, David J P; Oren, Ram; Palmroth, Sari; Phillips, Richard P; Pippen, Jeffrey S; Pritchard, Seth G; Treseder, Kathleen K; Schlesinger, William H; Delucia, Evan H; Finzi, Adrien C

    2011-04-01

    The earth's future climate state is highly dependent upon changes in terrestrial C storage in response to rising concentrations of atmospheric CO₂. Here we show that consistently enhanced rates of net primary production (NPP) are sustained by a C-cascade through the root-microbe-soil system; increases in the flux of C belowground under elevated CO₂ stimulated microbial activity, accelerated the rate of soil organic matter decomposition and stimulated tree uptake of N bound to this SOM. This process set into motion a positive feedback maintaining greater C gain under elevated CO₂ as a result of increases in canopy N content and higher photosynthetic N-use efficiency. The ecosystem-level consequence of the enhanced requirement for N and the exchange of plant C for N belowground is the dominance of C storage in tree biomass but the preclusion of a large C sink in the soil. PMID:21303437

  11. Elevated atmospheric carbon dioxide effects on cotton plant residue decomposition

    SciTech Connect

    Torbert, H.A.; Prior, S.A.; Rogers, H.H.

    1995-09-01

    Assessing the impact of elevated atmospheric CO{sub 2} concentration on the global environment is hampered due to a lack of understanding of global C cycling. Carbon fixed within plant biomass ultimately enters the soil via plant residues, but the effects of elevated-CO{sub 2}-grown plant material on decomposition rates and long-term soil C storage are unknown. The objective of this study was to determine the decomposition rate of plant residues grown under an elevated CO{sub 2} environment as affected by soil type. Cotton (Gossypium hirsutum L. `Delta Pine 77`) samples were collected from a free-air CO{sub 2} enrichment (550 {mu}L L{sup -1}) experiment. The plant residues were incubated under ambient CO{sub 2} conditions to determine decomposition rates of leaves, stems, and roots and potential N and P mineralization-immobilization in three soil series. No significant difference was observed between plant residue grown under CO{sub 2} enrichment vs. ambient CO{sub 2} conditions for soil respiration or P mineralization-immobilization. Significantly greater net N immobilization was observed during the incubation in all soil types for plant residue grown at elevated CO{sub 2}. These results indicate that while decomposition of plant residue may not be reduced by CO{sub 2} enrichment, N dynamics may be markedly changed. 32 refs., 5 figs., 3 tabs.

  12. Effect of climate change on C:N pools in a fringe boreal watershed: Will it complement long-term atmospheric N inputs

    SciTech Connect

    Stottlemyer, R. )

    1993-06-01

    The objective of this ongoing study is to assess if Possible changes in the nitrogen cycle, as predicted from global climate scenarios for temperature and moisture, might complement long-term inorganic precipitation nitrogen (N) inputs to boreal forests of Isle Royale. Change in ecosystem C is dependant on nutrient status especially N. Present atmospheric contaminant inputs of N (>6 kg ha[sup [minus]1] yr[sup [minus]1]) exceed the ecological requirements of major boreal forest species. A decade of boreal watershed level study shows strong N retention (92%). Large organic (21 % of above ground biomass) and N reservoirs (>550 kg ha[sup [minus]1]) in the forest floor suggest higher content of recalcitrant compounds and high inputs could reduce C:N ratios and accelerate N mineralization. This would accentuate atmospheric N inputs likely favoring conifers and possibly leading to N saturation.

  13. On the Sensitivity of Atmospheric Ensembles to Cloud Microphysics in Long-Term Cloud-Resolving Model Simulations

    NASA Technical Reports Server (NTRS)

    Zeng, Xiping; Tao, Wei-Kuo; Lang, Stephen; Hou, Arthur Y.; Zhang, Minghua; Simpson, Joanne

    2008-01-01

    Month-long large-scale forcing data from two field campaigns are used to drive a cloud-resolving model (CRM) and produce ensemble simulations of clouds and precipitation. Observational data are then used to evaluate the model results. To improve the model results, a new parameterization of the Bergeron process is proposed that incorporates the number concentration of ice nuclei (IN). Numerical simulations reveal that atmospheric ensembles are sensitive to IN concentration and ice crystal multiplication. Two- (2D) and three-dimensional (3D) simulations are carried out to address the sensitivity of atmospheric ensembles to model dimensionality. It is found that the ensembles with high IN concentration are more sensitive to dimensionality than those with low IN concentration. Both the analytic solutions of linear dry models and the CRM output show that there are more convective cores with stronger updrafts in 3D simulations than in 2D, which explains the differing sensitivity of the ensembles to dimensionality at different IN concentrations.

  14. Atmospheric Direct Uptake and Long-term Fate of Radiocesium in Trees after the Fukushima Nuclear Accident

    NASA Astrophysics Data System (ADS)

    Mahara, Yasunori; Ohta, Tomoko; Ogawa, Hideki; Kumata, Atsushi

    2014-11-01

    Large areas of forests were radioactively contaminated by the Fukushima nuclear accident of 2011, and forest decontamination is now an important problem in Japan. However, whether trees absorb radioactive fallout from soil via the roots or directly from the atmosphere through the bark and leaves is unclear. We measured the uptake of radiocesium by trees in forests heavily contaminated by the Fukushima nuclear accident. The radiocesium concentrations in sapwood of two tree species, the deciduous broadleaved konara (Quercus serrata) and the evergreen coniferous sugi (Cryptomeria japonica), were higher than that in heartwood. The concentration profiles showed anomalous directionality in konara and non-directionality in sugi, indicating that most radiocesium in the tree rings was directly absorbed from the atmosphere via bark and leaves rather than via roots. Numerical modelling shows that the maximum 137Cs concentration in the xylem of konara will be achieved 28 years after the accident. Conversely, the values for sugi will monotonously decrease because of the small transfer factor in this species. Overall, xylem 137Cs concentrations will not be affected by root uptake if active root systems occur 10 cm below the soil.

  15. Atmospheric direct uptake and long-term fate of radiocesium in trees after the Fukushima nuclear accident.

    PubMed

    Mahara, Yasunori; Ohta, Tomoko; Ogawa, Hideki; Kumata, Atsushi

    2014-01-01

    Large areas of forests were radioactively contaminated by the Fukushima nuclear accident of 2011, and forest decontamination is now an important problem in Japan. However, whether trees absorb radioactive fallout from soil via the roots or directly from the atmosphere through the bark and leaves is unclear. We measured the uptake of radiocesium by trees in forests heavily contaminated by the Fukushima nuclear accident. The radiocesium concentrations in sapwood of two tree species, the deciduous broadleaved konara (Quercus serrata) and the evergreen coniferous sugi (Cryptomeria japonica), were higher than that in heartwood. The concentration profiles showed anomalous directionality in konara and non-directionality in sugi, indicating that most radiocesium in the tree rings was directly absorbed from the atmosphere via bark and leaves rather than via roots. Numerical modelling shows that the maximum (137)Cs concentration in the xylem of konara will be achieved 28 years after the accident. Conversely, the values for sugi will monotonously decrease because of the small transfer factor in this species. Overall, xylem (137)Cs concentrations will not be affected by root uptake if active root systems occur 10 cm below the soil. PMID:25409781

  16. Long-term observation of water-soluble chemical components in the bulk atmospheric aerosols collected at Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Handa, Daishi; Somada, Yuka; Ijyu, Moriaki; Azechi, Sotaro; Nakaema, Fumiya; Arakaki, Takemitsu; Tanahara, Akira

    2010-05-01

    The economic development and population growth in recent Asia spread air pollution. Emission rate of air pollutants from Asia, in particular oxides of nitrogen, surpassed those from North America and Europe and should continue to exceed them for decades. The study of the long-range transported air pollution from Asian continent has gained a special attention in Japan because of increase in photochemical oxidants in relatively remote islands. Okinawa Island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km south of South Korea. Its location in Asia is well suited for studying long-range transport of air pollutants in East Asia because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background and can be compared with continental air masses which have been affected by anthropogenic activities. Bulk aerosol samples were collected on quartz filters by using a high volume air sampler. Sampling duration was one week for each sample. We determined the concentrations of water-soluble anions, cations and dissolved organic carbon (DOC) in the bulk aerosols collected at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) using ion chromatography, atomic absorption spectrometry, and total organic carbon analyzer, respectively. We will report water-soluble chemical components data of anions, cations and DOC in bulk atmospheric aerosols collected at CHAAMS during August, 2005 to April, 2010. Seasonal variation of water-soluble chemical components showed that the concentrations were relatively low in summer, higher in fall and winter, and the highest in spring. When air mass came from Asian Continent, the concentrations of water-soluble chemical components were much higher compared to the other directions. In addition, we calculated background concentration of water-soluble chemical components at Okinawa

  17. Can agricultural soils effectively remove legacy carbon from the atmosphere? Lessons from Australian long-term soil experiments. (Invited)

    NASA Astrophysics Data System (ADS)

    Sanderman, J.; Baldock, J.; Farquharson, R.

    2009-12-01

    One of the greatest changes that has occurred in soils during the Anthropocene is loss of organic matter due to agriculture. This loss has resulted in both large declines in soil fertility and large emissions of CO2 to the atmosphere. On the billions of hectares in production, humans are likely the only agent that will significantly change this situation. From a theoretical standpoint, any management practice which results in greater carbon return to the soil, increased stabilisation of soil carbon, or a reduction in losses should lead to positive carbon sequestration rates. Indeed, Australian field trial evidence indicates that there was a relative gain in soil carbon between most conventional and improved-management treatments. However, when soil carbon stocks were followed through time, the majority of these same studies indicated that there was an actual decrease in the quantity of carbon stored in the soil even in the improved-management treatments. These seemingly contradictory results suggest that many agricultural soils may still be responding to initial land clearing and that many management improvements are just slowing the loss soil carbon. This reduction in rate of loss of soil carbon represents a real greenhouse gas abatement in the form of avoided emissions. However, the predictive power of results from most agronomic field trials to alternative situations where these management practices have been implemented is questionable without detailed knowledge of the state of the soil carbon in the systems being considered.

  18. Long-term records of fire occurrence and their implications for gaseous and particulate emissions to the atmosphere

    SciTech Connect

    Clark, J.S.; Stocks, B.J. Forestry Canada, Sault Ste, Marie, Ontario )

    1993-06-01

    Changing climate and land use appear to importantly affect the biosphere by way of impacts on fire regimes. Feedback effects on climate and air quality are likely through emissions of trace gases, aerosols, and particulates that affect radiation budgets, stability of the troposphere, and biogeochemical and hydrologic cycles. Paleorecords of biomass burning are available in the form of stratigraphic charcoal in lake and mire deposits and fire scars on trees. When taken together with recent emissions data from experimental bums and wildland fires they hold promise for estimation of how changing fire regimes may be affecting atmospheric composition. We synthesize existing evidence for effects of global change on fire regimes for each of the major biomes. Fire regimes vary in their sensitivities to changing climate, with woodland/savanna types and boreal forest among the most sensitive. Emissions have greatly increased with changing human influences in some vegetation types (temperate and some low-latitude biomes) and decreased in others (temperate pine forests). Some biomes, including boreal forests, hold promise for rather detailed reconstructions of past emissions. We recommend that future efforts focus on those regions where the importance of fire and availability of paleodata are greatest.

  19. X-rays absorption study on medieval corrosion layers for the understanding of very long-term indoor atmospheric iron corrosion

    NASA Astrophysics Data System (ADS)

    Monnier, J.; Réguer, S.; Vantelon, D.; Dillmann, P.; Neff, D.; Guillot, I.

    2010-05-01

    The study and prediction of very long-term atmospheric corrosion behaviour of ferrous alloys is of great importance in different fields. First the conservation of metallic artefacts in museum and the corrosion diagnosis on ferrous reinforcement used in ancient monuments since medieval times needs reliable data to understand the mechanisms. Second, in the frame of the interim storage of nuclear waste in France, it is necessary to model the long-term corrosion of low alloy steel overcontainer. The nature of phases and elements constituting the corrosion layers can greatly influence the corrosion mechanisms. On the one hand, it is crucial to precisely determine the nature of microscopic phases that can be highly reactive. On the other hand, some elements as P and S could modify this reactivity. To clarify this point and complementary to other studies using Raman micro spectroscopy technique, X-rays Absorption Spectroscopy (XAS) under synchrotron radiation plays a crucial role. It allows one to precisely identify the reactive phases in the corrosion layers. Micro-XAS was required in order to refine the spatial variation, at micrometer scale, of the predominant Fe oxidation state and to characterise the corresponding corrosion products. Moreover, the role of minor elements on phase’s stability and the chemical form of these elements in the rust layer, especially phosphorus and sulphur, was investigated.

  20. Long-term effects of changing atmospheric pollution on throughfall, bulk deposition and streamwaters in a Mediterranean forest.

    PubMed

    Aguillaume, Laura; Rodrigo, Anselm; Avila, Anna

    2016-02-15

    The abatement programs implanted in Europe to reduce SO2, NO2 and NH3 emissions are here evaluated by analyzing the relationships between emissions in Spain and neighboring countries and atmospheric deposition in a Mediterranean forest in the Montseny mountains (NE Spain) for the last 3decades. A canopy budget model was applied to throughfall data measured during a period of high emissions (1995-1996) and a period of lower emissions (2011-2013) to estimate the changes in dry deposition over this time span. Emissions of SO2 in Spain strongly decreased (77%) and that was reflected in reductions for nssSO4(2-) in precipitation (65% for concentrations and 62% for SO4(2)-S deposition). A lower decline was found for dry deposition (29%). Spanish NO2 emissions increased from 1980 to 1991, remained constant until 2005, and decreased thereafter, a pattern that was paralleled by NO3(-) concentrations in bulk precipitation at Montseny. This pattern seems to be related to a higher share of renewable energies in electricity generation in Spain in recent years. However, dry deposition increased markedly between 1995 and 2012, from 1.3 to 6.7 kg ha(-1) year(-)(1). Differences in meteorology between periods may have had a role, since the recent period was drier thus probably favoring dry deposition. Spanish NH3 emissions increased by 13% between 1980 and 2012 in Spain but NH4(+) concentrations in precipitation and NH4(+)-N deposition showed a decreasing trend (15% reduction) at Montseny, probably linked to the reduction ammonium sulfate and nitrate aerosols to be scavenged by rainfall. NH4(+)-N dry deposition was similar between the compared periods. The N load at Montseny (15-17 kg ha(-1)y ear(-1)) was within the critical load range proposed for Mediterranean sclerophyllous forests (15-17.5 kg ha(-1) year(-1)). The onset of N saturation is suggested by the observed increasing N export in streamwaters. PMID:26706764

  1. Tree bark suber-included particles: A long-term accumulation site for elements of atmospheric origin

    NASA Astrophysics Data System (ADS)

    Catinon, Mickaël; Ayrault, Sophie; Spadini, Lorenzo; Boudouma, Omar; Asta, Juliette; Tissut, Michel; Ravanel, Patrick

    2011-02-01

    The deposition of atmospheric elements on and into the bark of 4-year-old Fraxinus excelsior L. was studied. The elemental composition of the suber tissue was established through ICP-MS analysis and the presence of solid mineral particles included in this suber was established and described through SEM-EDX. Fractionation of the suber elements mixture was obtained after ashing at 550 °C through successive water (C fraction) and HNO 3 2 M (D fraction) extraction, leading to an insoluble residue mainly composed of the solid mineral particles (E fraction). The triplicated % weight of C, D and E were respectively 34.4 ± 2.7, 64.8 ± 2.7 and 0.8 ± 0.1% of the suber ashes weight. The main component of C was K, of D was Ca. Noticeable amounts of Mg were also observed in D. The E fraction, composed of insoluble particles, was mostly constituted of geogenic products, with elements such as Si, Al, K, Mg, representing primary minerals. E also contained Ca 3(PO 4) 2 and concentrated the main part of Pb and Fe. Moreover, The SEM-EDX analysis evidenced that this fraction also concentrated several types of fly ashes of industrial origin. The study of the distribution between C, D and E was analysed through ICP-MS with respect to their origin. The origin of the elements found in such bark was either geogenic (clay, micas, quartz…), anthropogenic or biogenic (for instance large amounts of solid Ca organic salts having a storage role). As opposed to the E fraction, the C fraction, mainly composed of highly soluble K+ is characteristic of a biological pool of plant origin. In fraction D, the very high amount of Ca++ corresponds to two different origins: biological or acid soluble minerals such as calcite. Furthermore, the D fraction contains the most part of pollutants of anthropic origin such as Zn, Cu, Ni, Co, Cd. As a whole, the fractionation procedure of the suber samples allows to separate elements as a function of their origin but also gives valuable information on

  2. Long-term changes and trends in total ozone over the northern mid-latitudes: Influence of atmospheric dynamics and chemistry and contribution from extreme events

    NASA Astrophysics Data System (ADS)

    Rieder, H. E.; Staehelin, J.; Maeder, J. A.; Ribatet, M.; di Rocco, S.; Frossard, L.; Jancso, L. M.; Peter, T.; Davison, A. C.

    2010-12-01

    Downward trends in global stratospheric ozone during recent decades have been shown to be directly linked to increasing surface UV-radiation. In the past, long-term ozone trends were determined from homogenized data series by fitting with multiple linear regression models, in which suitable independent variables (so-called explanatory variables) were used to represent atmospheric variability, such as the Quasi-Biennial Oscillation (QBO), the 11-year solar cycle, and a linear trend attributed to anthropogenic ozone depletion. Previous studies have identified a number of other processes influencing total ozone at mid-latitudes, such as synoptic-scale meteorological variability, decadal or long-term climate variability, described e.g. by the Northern Atlantic Oscillation (NAO), the Arctic Oscillation (AO), atmospheric circulation indices ENSO, temperature at the 470-K isentrope level, and volcanic eruptions. Due to the successful implementation of the Montreal Protocol the discussion about a recovery or possible “super recovery” started within the scientific community. Here we address long-term changes and trends in a different framework. As statistical analysis showed that previously used concepts assuming a Gaussian distribution of total ozone data do not address the internal data structure concerning extremes adequately methods from extreme value theory are applied on local (various long-term ground based total ozone records) and regional (high resolution homogenized satellite data) scale. Within the extreme value theory framework days with extreme low (ELOs) and high (EHOs) total ozone are analyzed and their frequency is linked to changes in atmospheric chemistry and dynamics. The results show: (i) an increase in ELOs and (ii) a decrease in EHOs during the last decades and (iii) that the overall trend during the 1970s and 1980s in total ozone is strongly dominated by changes in these extreme events. After removing the extremes, the different time series show a

  3. Searching for a Relationship Between Forest Water Use and Increasing Atmospheric CO2 Concentration with Long-Term Hydrologic Data from the Hubbard Brook Experimental Forest

    SciTech Connect

    Amthor, J.S.

    1998-11-01

    Increases in atmospheric C02 concentration from mid-1956 through mid-1997 were compared with hydrologic records from five forested, gaged watersheds in the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, U.S.A. The purpose of the comparison was to assess whether a relationship between increasing atmospheric CO2 concentration and whole-ecosystem evapotranspiration (ET) could be determined. The HBEF is particularly well suited to this type of study because of the length of the hydrologic record and the physical properties of the watersheds. This analysis is based on HBEF water years (which begin 1 June and end the following 31 May) rather than calendar years. Hydrologic records from individual watersheds used in this analysis ranged from 28 to 41 water years. During the full 41-water-year period, it is estimated that water-year mean atmospheric CO2 concentration increased more than 15% (from about 314 to 363 ppm). In one south-facing watershed (i.e., HBEF watershed 3), there was a statistically significant negative relationship between atmospheric C02 concentration and ET. This translated into a nearly 77 rnndyear reduction in ET as a result of a 50 ppm increase in atmospheric C02 concentration, a result of practical significance. Evapotranspiration from the other watersheds was also negatively related to atmospheric CO2 concentration, but with smaller (and statistically insignificant) magnitudes. Evapotranspiration from the three south-facing (but not the two north-facing) watersheds included in the analysis was "abnormally" low during the most recent 2 years (i.e., water years beginning in 1995 and 1996), and this affected the trends in ET. This recent and abrupt, reduction in ET deserves further analysis, most importantly by an extension of the hydrologic record through continued long-term monitoring in the HBEF (which is ongoing). If ET remains relatively low during the coming years in south-facing watersheds, studies of the physical and/or biological

  4. The Long Term Effects of Social Skills Training in Elevating Overall Academic Grade Point Average, School Attendance, Health Level, and Resistance to Drug Use and Peer Pressure.

    ERIC Educational Resources Information Center

    Richards, Nancy; Smith, Manuel J.

    Project STAR (Social Thinking and Reasoning Program) is a classroom-based social skills program for students in grades 5-8. To assess the long-term effectiveness of this program, students participated in the project (N=331) were compared with control students (N=191) during 1980-83. The hypothesis that there are significant differences in current…

  5. Tracing changes in N transformations in a permanent grassland under elevated atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Moser, Gerald; Gorenflo, André; Brenzinger, Kristof; Keidel, Lisa; Elias, Dafydd; McNamara, Niall; Maček, Irena; Vodnik, Dominik; Braker, Gesche; Schimmelpfennig, Sonja; Gerstner, Judith; Müller, Christoph

    2015-04-01

    Long-term observations (> 14 years) within the Giessen Free Air Carbon dioxide Enrichment (Giessen FACE) study on permanent grassland showed that the carbon fertilization caused significant changes in the ecosystem nitrogen cycle. The goal of this study is to understand the long-term effects of elevated atmospheric CO2 and carbon input on the soil N transformations and plant N uptake in the Giessen FACE study. A pulse labelling with 15N tracing of 15NH4+ and 15NO3- was carried out in situ. Different fractions of soil organic matter (recalcitrant, labile SOM) and the various mineral N pools in the soil (NH4+, NO3-), simultaneous gross N transformation rates, N species dependent plant N uptake have been quantified. The quantification of the gross N transformations are based on the turnover of NH4+, NO3- and shall illuminate the interaction between carbon fertilization and changes in nitrogen cycle in this grassland ecosystem. Under elevated atmospheric CO2, results shortly after N fertilization differed from long-term results and are in line with the long-term trace gas record of the site. In particular the ammonia oxidation, the mineralisation-immobilisation turnover, as well as dissimilatory nitrate reduction to ammonia (DNRA) and N plant uptake were affected. To further elucidate the microbial dynamics, the microbial communities and in particular the activity of the denitrifiers were evaluated.

  6. Microstructure and Property Evolution in Advanced Cladding and Duct Materials Under Long-Term and Elevated Temperature Irradiation: Modeling and Experimental Investigation

    SciTech Connect

    Wirth, Brian; Morgan, Dane; Kaoumi, Djamel; Motta, Arthur

    2013-12-01

    irradiation. This project will focus on modeling microstructural and microchemical evolution of irradiated alloys by performing detailed modeling of such microstructure evolution processes coupled with well-designed in situ experiments that can provide validation and benchmarking to the computer codes. The broad scientific and technical objectives of this proposal are to evaluate the microstructure and microchemical evolution in advanced ferritic/martensitic and oxide dispersion strengthened (ODS) alloys for cladding and duct reactor materials under long-term and elevated temperature irradiation, leading to improved ability to model structural materials performance and lifetime. Specifically, we propose four research thrusts, namely Thrust 1: Identify the formation mechanism and evolution for dislocation loops with Burgers vector of a<100> and determine whether the defect microstructure (predominately dislocation loop/dislocation density) saturates at high dose. Thrust 2: Identify whether a threshold irradiation temperature or dose exists for the nucleation of growing voids that mark the beginning of irradiation-induced swelling, and begin to probe the limits of thermal stability of the tempered Martensitic structure under irradiation. Thrust 3: Evaluate the stability of nanometer sized Y- Ti-O based oxide dispersion strengthened (ODS) particles at high fluence/temperature. Thrust 4: Evaluate the extent to which precipitates form and/or dissolve as a function of irradiation temperature and dose, and how these changes are driven by radiation induced segregation and microchemical evolutions and determined by the initial microstructure.

  7. Long-term variations in abundance and distribution of sulfuric acid vapor in the Venus atmosphere inferred from Pioneer Venus and Magellan radio occultation studies

    NASA Technical Reports Server (NTRS)

    Jenkins, J. M.; Steffes, P. G.

    1992-01-01

    Radio occultation experiments have been used to study various properties of planetary atmospheres, including pressure and temperature profiles, and the abundance profiles of absorbing constituents in those planetary atmospheres. However, the reduction of amplitude data from such experiments to determine abundance profiles requires the application of the inverse Abel transform (IAT) and numerical differentiation of experimental data. These two operations preferentially amplify measurement errors above the true signal underlying the data. A new technique for processing radio occultation data has been developed that greatly reduces the errors in the derived absorptivity and abundance profiles. This technique has been applied to datasets acquired from Pioneer Venus Orbiter radio occultation studies and more recently to experiments conducted with the Magellan spacecraft. While primarily designed for radar studies of the Venus surface, the high radiated power (EIRP) from the Magellan spacecraft makes it an ideal transmitter for measuring the refractivity and absorptivity of the Venus atmosphere by such experiments. The longevity of the Pioneer Venus Orbiter has made it possible to study long-term changes in the abundance and distribution of sulfuric acid vapor, H2SO4(g), in the Venus atmosphere between 1979 and 1992. The abundance of H2SO4(g) can be inferred from vertical profiles of 13-cm absorptivity profiles retrieved from radio occultation experiments. Data from 1979 and 1986-87 suggest that the abundance of H2SO4(g) at latitudes northward of 70 deg decreased over this time period. This change may be due to a period of active volcanism in the late 1970s followed by a relative quiescent period, or some other dynamic process in the Venus atmosphere. While the cause is not certain, such changes must be incorporated into dynamic models of the Venus atmosphere. Potentially, the Magellan spacecraft will extend the results of Pioneer Venus Orbiter and allow the continued

  8. Building long-term and high spatio-temporal resolution precipitation and air temperature reanalyses by mixing local observations and global atmospheric reanalyses: the ANATEM model

    NASA Astrophysics Data System (ADS)

    Kuentz, A.; Mathevet, T.; Gailhard, J.; Hingray, B.

    2015-06-01

    Efforts to improve the understanding of past climatic or hydrologic variability have received a great deal of attention in various fields of geosciences such as glaciology, dendrochronology, sedimentology and hydrology. Based on different proxies, each research community produces different kinds of climatic or hydrologic reanalyses at different spatio-temporal scales and resolutions. When considering climate or hydrology, many studies have been devoted to characterising variability, trends or breaks using observed time series representing different regions or climates of the world. However, in hydrology, these studies have usually been limited to short temporal scales (mainly a few decades and more rarely a century) because they require observed time series (which suffer from a limited spatio-temporal density). This paper introduces ANATEM, a method that combines local observations and large-scale climatic information (such as the 20CR Reanalysis) to build long-term probabilistic air temperature and precipitation time series with a high spatio-temporal resolution (1 day and a few km2). ANATEM was tested on the reconstruction of air temperature and precipitation time series of 22 watersheds situated in the Durance River basin, in the French Alps. Based on a multi-criteria and multi-scale diagnosis, the results show that ANATEM improves the performance of classical statistical models - especially concerning spatial homogeneity - while providing an original representation of uncertainties which are conditioned by atmospheric circulation patterns. The ANATEM model has been also evaluated for the regional scale against independent long-term time series and was able to capture regional low-frequency variability over more than a century (1883-2010).

  9. Mobility particle size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions

    NASA Astrophysics Data System (ADS)

    Wiedensohler, A.; Birmili, W.; Nowak, A.; Sonntag, A.; Weinhold, K.; Merkel, M.; Wehner, B.; Tuch, T.; Pfeifer, S.; Fiebig, M.; Fjäraa, A. M.; Asmi, E.; Sellegri, K.; Depuy, R.; Venzac, H.; Villani, P.; Laj, P.; Aalto, P.; Ogren, J. A.; Swietlicki, E.; Williams, P.; Roldin, P.; Quincey, P.; Hüglin, C.; Fierz-Schmidhauser, R.; Gysel, M.; Weingartner, E.; Riccobono, F.; Santos, S.; Grüning, C.; Faloon, K.; Beddows, D.; Harrison, R.; Monahan, C.; Jennings, S. G.; O'Dowd, C. D.; Marinoni, A.; Horn, H.-G.; Keck, L.; Jiang, J.; Scheckman, J.; McMurry, P. H.; Deng, Z.; Zhao, C. S.; Moerman, M.; Henzing, B.; de Leeuw, G.; Löschau, G.; Bastian, S.

    2012-03-01

    Mobility particle size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide range of applications in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards and guidelines with respect to the instrumental set-up, measurement mode, data evaluation as well as quality control. Technical standards were developed for a minimum requirement of mobility size spectrometry to perform long-term atmospheric aerosol measurements. Technical recommendations include continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyzer. We compared commercial and custom-made inversion routines to calculate the particle number size distributions from the measured electrical mobility distribution. All inversion routines are comparable within few per cent uncertainty for a given set of raw data. Furthermore, this work summarizes the results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research) and ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) to determine present uncertainties especially of custom-built mobility particle size spectrometers. Under controlled laboratory conditions, the particle number size distributions from 20 to 200 nm determined by mobility particle size spectrometers of different design are within an uncertainty range of around ±10% after correcting internal particle losses, while below and above this size range the discrepancies increased. For particles larger than 200 nm, the uncertainty range increased to 30%, which could not be explained. The network reference mobility spectrometers with identical design agreed within ±4% in the peak particle number concentration

  10. Particle mobility size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions

    NASA Astrophysics Data System (ADS)

    Wiedensohler, A.; Birmili, W.; Nowak, A.; Sonntag, A.; Weinhold, K.; Merkel, M.; Wehner, B.; Tuch, T.; Pfeifer, S.; Fiebig, M.; Fjäraa, A. M.; Asmi, E.; Sellegri, K.; Depuy, R.; Venzac, H.; Villani, P.; Laj, P.; Aalto, P.; Ogren, J. A.; Swietlicki, E.; Roldin, P.; Williams, P.; Quincey, P.; Hüglin, C.; Fierz-Schmidhauser, R.; Gysel, M.; Weingartner, E.; Riccobono, F.; Santos, S.; Grüning, C.; Faloon, K.; Beddows, D.; Harrison, R. M.; Monahan, C.; Jennings, S. G.; O'Dowd, C. D.; Marinoni, A.; Horn, H.-G.; Keck, L.; Jiang, J.; Scheckman, J.; McMurry, P. H.; Deng, Z.; Zhao, C. S.; Moerman, M.; Henzing, B.; de Leeuw, G.

    2010-12-01

    Particle mobility size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide application in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards with respect to the instrumental set-up, measurement mode, data evaluation as well as quality control. This article results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research). Under controlled laboratory conditions, the number size distribution from 20 to 200 nm determined by mobility size spectrometers of different design are within an uncertainty range of ±10% after correcting internal particle losses, while below and above this size range the discrepancies increased. Instruments with identical design agreed within ±3% in the peak number concentration when all settings were done carefully. Technical standards were developed for a minimum requirement of mobility size spectrometry for atmospheric aerosol measurements. Technical recommendations are given for atmospheric measurements including continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyser. In cooperation with EMEP (European Monitoring and Evaluation Program), a new uniform data structure was introduced for saving and disseminating the data within EMEP. This structure contains three levels: raw data, processed data, and final particle size distributions. Importantly, we recommend reporting raw measurements including all relevant instrument parameters as well as a complete documentation on all data transformation and correction steps. These technical and data structure standards aim to enhance the quality of long-term size distribution measurements, their comparability between

  11. Improving the Long-Term Stability of Atmospheric Surface Deformation Predictions by Mitigating the Effects of Orography Updates in Operational Weather Forecast Models

    NASA Astrophysics Data System (ADS)

    Dill, Robert; Bergmann-Wolf, Inga; Thomas, Maik; Dobslaw, Henryk

    2016-04-01

    The global numerical weather prediction model routinely operated at the European Centre for Medium-Range Weather Forecasts (ECMWF) is typically updated about two times a year to incorporate the most recent improvements in the numerical scheme, the physical model or the data assimilation procedures into the system for steadily improving daily weather forecasting quality. Even though such changes frequently affect the long-term stability of meteorological quantities, data from the ECMWF deterministic model is often preferred over alternatively available atmospheric re-analyses due to both the availability of the data in near real-time and the substantially higher spatial resolution. However, global surface pressure time-series, which are crucial for the interpretation of geodetic observables, such as Earth rotation, surface deformation, and the Earth's gravity field, are in particular affected by changes in the surface orography of the model associated with every major change in horizontal resolution happened, e.g., in February 2006, January 2010, and May 2015 in case of the ECMWF operational model. In this contribution, we present an algorithm to harmonize surface pressure time-series from the operational ECMWF model by projecting them onto a time-invariant reference topography under consideration of the time-variable atmospheric density structure. The effectiveness of the method will be assessed globally in terms of pressure anomalies. In addition, we will discuss the impact of the method on predictions of crustal deformations based on ECMWF input, which have been recently made available by GFZ Potsdam.

  12. Atmospheric and terrestrial water budgets: sensitivity and performance of configurations and global driving data for long term continental scale WRF simulations

    NASA Astrophysics Data System (ADS)

    Fersch, Benjamin; Kunstmann, Harald

    2014-05-01

    Driving data and physical parametrizations can significantly impact the performance of regional dynamical atmospheric models in reproducing hydrometeorologically relevant variables. Our study addresses the water budget sensitivity of the Weather Research and Forecasting Model System WRF (WRF-ARW) with respect to two cumulus parametrizations (Kain-Fritsch, Betts-Miller-Janjić), two global driving reanalyses (ECMWF ERA-INTERIM and NCAR/NCEP NNRP), time variant and invariant sea surface temperature and optional gridded nudging. The skill of global and downscaled models is evaluated against different gridded observations for precipitation, 2 m-temperature, evapotranspiration, and against measured discharge time-series on a monthly basis. Multi-year spatial deviation patterns and basin aggregated time series are examined for four globally distributed regions with different climatic characteristics: Siberia, Northern and Western Africa, the Central Australian Plane, and the Amazonian tropics. The simulations cover the period from 2003 to 2006 with a horizontal mesh of 30 km. The results suggest a high sensitivity of the physical parametrizations and the driving data on the water budgets of the regional atmospheric simulations. While the global reanalyses tend to underestimate 2 m-temperature by 0.2-2 K, the regional simulations are typically 0.5-3 K warmer than observed. Many configurations show difficulties in reproducing the water budget terms, e.g. with long-term mean precipitation biases of 150 mm month-1 and higher. Nevertheless, with the water budget analysis viable setups can be deduced for all four study regions.

  13. Effects of Long-Term CO2 Enrichment on Soil-Atmosphere CH4 Fluxes and the Spatial Micro-Distribution of Methanotrophic Bacteria

    PubMed Central

    Karbin, Saeed; Guillet, Cécile; Kammann, Claudia I.; Niklaus, Pascal A.

    2015-01-01

    Background Effects of elevated atmospheric CO2 concentrations on plant growth and associated C cycling have intensively been studied, but less is known about effects on the fluxes of radiatively active trace gases other than CO2. Net soil-atmosphere CH4 fluxes are determined by the balance of soil microbially-driven methane (CH4) oxidation and methanogenesis, and both might change under elevated CO2. Methods and Results Here, we studied CH4 dynamics in a permanent grassland exposed to elevated CO2 for 14 years. Soil-atmosphere fluxes of CH4 were measured using large static chambers, over a period of four years. The ecosystem was a net sink for atmospheric CH4 for most of the time except summer to fall when net CH4 emissions occurred. We did not detect any elevated CO2 effects on CH4 fluxes, but emissions were difficult to quantify due to their discontinuous nature, most likely because of ebullition from the saturated zone. Potential methanotrophic activity, determined by incubation of fresh sieved soil under standardized conditions, also did not reveal any effect of the CO2 treatment. Finally, we determined the spatial micro-distribution of methanotrophic activity at less than 5× atmospheric (10 ppm) and elevated (10000 ppm) CH4 concentrations, using a novel auto-radiographic technique. These analyses indicated that domains of net CH4 assimilation were distributed throughout the analyzed top 15 cm of soils, with no dependence on CH4 concentration or CO2 treatment. Conclusions Our investigations suggest that elevated CO2 exerts no or only minor effects on CH4 fluxes in the type of ecosystem we studied, at least as long as soil moisture differences are small or absent as was the case here. The autoradiographic analyses further indicate that the spatial niche of CH4 oxidation does not shift in response to CO2 enrichment or CH4 concentration, and that the same type of methanotrophs may oxidize CH4 from atmospheric and soil-internal sources. PMID:26147694

  14. On the role of atmosphere-ocean interactions in the expected long-term changes of the Earth's ozone layer caused by greenhouse gases

    NASA Astrophysics Data System (ADS)

    Zadorozhny, Alexander; Dyominov, Igor

    It is well known that anthropogenic emissions of greenhouse gases into the atmosphere produce a global warming of the troposphere and a global cooling of the stratosphere. The expected stratospheric cooling essentially influences the ozone layer via increased polar stratospheric cloud formation and via temperature dependences of the gas phase reaction rates. One more mechanism of how greenhouse gases influences the ozone layer is enhanced water evaporation from the oceans into the atmosphere because of increasing temperatures of the ocean surface due to greenhouse effect. The subject of this paper is a study of the influence of anthropogenic pollution of the atmosphere by the greenhouse gases CO2, CH4, N2O and ozone-depleting chlorine and bromine compounds on the expected long-term changes of the ozone layer with taking into account an increase of water vapour content in the atmosphere due to greenhouse effect. The study based on 2-D zonally averaged interactive dynamical radiative-photochemical model of the troposphere and stratosphere. The model allows to self-consistently calculating diabatic circulation, temperature, gaseous composition of the troposphere and stratosphere at latitudes from the South to North Poles, as well as distribution of sulphate aerosol particles and polar stratospheric clouds of two types. It was supposed in the model that an increase of the ocean surface temperature caused by greenhouse effect is similar to calculated increase of atmospheric surface temperature. Evaporation rate from the ocean surface was computed in dependence of latitude. The model time-dependent runs were made for the period from 1975 to 2100 using two IPCC scenarios depicting maximum and average expected increases of greenhouse gases in the atmosphere. The model calculations show that anthropogenic increasing of water vapour abundance in the atmosphere due to heating of the ocean surface caused by greenhouse effect gives a sensible contribution to the expected ozone

  15. Long-term effect of β-blocker in ST-segment elevation myocardial infarction in patients with preserved left ventricular systolic function: a propensity analysis.

    PubMed

    Konishi, Hirokazu; Miyauchi, Katsumi; Kasai, Takatoshi; Tsuboi, Shuta; Ogita, Manabu; Naito, Ryo; Nishizaki, Yuji; Okai, Iwao; Tamura, Hiroshi; Okazaki, Shinya; Isoda, Kikuo; Daida, Hiroyuki

    2016-04-01

    The current guidelines for acute myocardial infarction (AMI) recommended that β-blocker should be used in patients with decreased left ventricular (LV) systolic function for long-term period. However, the effect of β-blocker in AMI patients with preserved LV systolic function is uncertain. We sought to assess the long-term effect of β-blocker in AMI patients with preserved LV systolic function. During the follow-up period (1997-2011), total 3508 patients were performed percutaneous coronary intervention (PCI). Of these patients, 424 AMI patients with preserved LV systolic function [ejection fraction (EF) > 40 %] were analyzed. Median follow-up period was 4.7 years. Then, patients were divided into two groups (β-blocker group 197 patients and no-β-blocker group 227 patients). However, there are substantial differences in baseline characteristics between two groups. Therefore, we calculated propensity score to match the patients in β-blocker and no-β-blocker groups. After post-match patients (N = 206, 103 matched pair), β-blocker therapy significantly reduced cardiac death compared with no-β-blocker [hazard ratio (HR) 0.40, p = 0.04], whereas β-blocker therapy was not associated with major adverse cardiac events (MACE) and all-cause death. β-Blocker is an effective treatment for AMI patients who underwent PCI with preserved LV systolic function. PMID:25573259

  16. Clinical Profile and Long-Term Prognostic Factors of a Young Chinese Han Population (≤ 40 Years) Having ST-Segment Elevation Myocardial Infarction

    PubMed Central

    Qian, Geng; Zhou, Ying; Liu, Hong-Bin; Chen, Yun-Dai

    2015-01-01

    Background The proportion of the mainland Chinese population with premature ST-segment elevation myocardial infarction is significantly elevated. Young patients with ST-segment elevation myocardial infarction have a different risk factor profile and clinical outcome compared with elder patients, and may also differ as compared to young patients in Western populations. Methods We analyzed a total of 9462 consecutive ST-segment elevation myocardial infarction patients, and recruited 341 consecutive cases who had survived their first ST-segment elevation myocardial infarction at the age less than 40 years, and followed-up these patients for 5 years. Results The most prevalent risk factor in young Chinese ST-segment elevation myocardial infarction patients was smoking (307/341, 90.03%) and male gender (328/341, 96.19%), although young patients had fewer traditional risk factors of acute myocardial infarction than the control group [(1.63 ± 1.03) vs. (2.38 ± 1.15), p < 0.01]. The number of affected vessels in cases was significantly less than in the elder control group (p < 0.01). During the follow-up, blood lipids and blood pressure of most patients reached the target level, while 42.10% of patients reported continuation of smoking. Multivariable data analysis showed that persistence of smoking (OR: 3.784, 95% CI: 1.636-8.751, p < 0.01) was the most significant prognostic factor of cardiac events after adjusting for various confounding factors. Conclusions We demonstrated that cigarette smoking is the most prevalent factor among the avoidable cardiovascular risk factors for young ST-segment elevation myocardial infarctions in China. Accordingly, continued smoking is the most powerful predictor for the recurrence of cardiac events in young Chinese patients with ST-segment elevation myocardial infarction. PMID:27122898

  17. Atmospheric drivers that compromise the assumed long-term stationarity between δ18O-based proxy records and NAO, winter air temperature and winter precipitation amount.

    NASA Astrophysics Data System (ADS)

    Comas Bru, Laia; McDermott, Frank; Werner, Martin

    2016-04-01

    The control exerted by large scale atmospheric circulation modes on the oxygen isotopic composition of precipitation (δ18Op) has been utilised to infer past atmospheric circulation states using proxies that capture δ18Op at a wide range of locations. Such reconstructions typically rely on the oxygen isotopic composition of terrestrial archives such as ice-cores, tree rings, speleothems and lacustrine carbonates and are underpinned by assumptions about a long term stationarity of the influence of the atmospheric teleconnection pattern of interest on δ18Op. However, such reconstructions should also consider the uncertainties that arise from non-stationarities in the δ18Op-NAO relationship during the instrumental period. Here, new insights into the causes of these temporal non-stationarities are presented for the European region using both observations (GNIP database) and the output of an isotope-enabled general circulation model (ECHAM5-wiso). The results show that, although the East Atlantic (EA) pattern is generally uncorrelated to δ18Op during the instrumental period, its polarity affects the strength of the δ18Op-NAO relationship in some European locations. Non-stationarities in this relationship can be rationalised through changes in the sea-level pressure structure in the N. Atlantic region as a result of the concomitant states of the NAO and EA patterns, which affect the trajectories of the air-masses carrying moisture onto Europe and ultimately the δ18Op signal. These shifts are consistent with those reported previously for NAO-winter climate variables and the resulting non-stationarities mean that δ18O-based NAO reconstructions could be compromised if the balance of positive and negative NAO/EA states differs substantially in a calibration period compared with the period of interest in the past. The same approach has been followed to assess the relationships between δ18Op and both winter total precipitation and winter mean surface air temperature

  18. Influence of wildfires on atmospheric composition and carbon uptake of forest ecosystems in Central Siberia: the establishing of a long-term post-fire monitoring system

    NASA Astrophysics Data System (ADS)

    Panov, Alexey; Chi, Xuguang; Winderlich, Jan; Prokushkin, Anatoly; Bryukhanov, Alexander; Korets, Mikhail; Ponomarev, Evgenii; Timokhina, Anastasya; Andreae, Meinrat O.; Heimann, Martin

    2014-05-01

    Calculations of direct emissions of greenhouse gases from boreal wildfires remain uncertain due to problems with emission factors, available carbon, and imprecise estimates of burned areas. Even more varied and sparse are accurate in situ calculations of temporal changes in boreal forest carbon dynamics following fire. Linking simultaneous instrumental atmospheric observations, GIS-based estimates of burned areas, and ecosystem carbon uptake calculations is vital to fill this knowledge gap. Since 2006 the Zotino Tall Tower Observatory (ZOTTO; www.zottoproject.org) a research platform for large-scale climatic observations is operational in Central Siberia (60°48'N, 89°21'E). The data of ongoing greenhouse gases measurements at the tower are used in atmospheric inversions studies to infer the distribution of carbon sinks and sources over central Northern Eurasia. We present our contribution to reducing uncertainties in estimates of fire influence on atmospheric composition and post-fire ecosystem carbon uptake deduced from the large-scale fires that happened in 2012 in the tall tower footprint area. The burned areas were estimated from Landsat ETM 5,8 satellite images, while fires were detected from Terra/Aqua MODIS satellite data. The magnitude of ecological change caused by fires ("burn severity") was measured and mapped with a Normalized Burn Ratio (NBR) index and further calibrated by a complementary field based Composite Burn Index (CBI). Measures of fire radiative power (FRP) index provided information on fire heat release intensity and on the amount and completeness of biomass combustion. Based on the analyzed GIS data, the system of study plots was established in the 5 dominating ecosystem types for a long-term post-fire monitoring. On the plots the comprehensive estimation of ecosystem parameters and carbon pools and their mapping was organized with a laser-based field instrumentation system. The work was supported financially by ISTC Project # 2757p

  19. Long-term growth under elevated CO2 suppresses biotic stress genes in non-acclimated, but not cold-acclimated winter wheat.

    PubMed

    Kane, Khalil; Dahal, Keshav P; Badawi, Mohamed A; Houde, Mario; Hüner, Norman P A; Sarhan, Fathey

    2013-11-01

    This study compared the photosynthetic performance and the global gene expression of the winter hardy wheat Triticum aestivum cv Norstar grown under non-acclimated (NA) or cold-acclimated (CA) conditions at either ambient CO2 or elevated CO2. CA Norstar maintained comparable light-saturated and CO2-saturated rates of photosynthesis but lower quantum requirements for PSII and non-photochemical quenching relative to NA plants even at elevated CO2. Neither NA nor CA plants were sensitive to feedback inhibition of photosynthesis at elevated CO2. Global gene expression using microarray combined with bioinformatics analysis revealed that genes affected by elevated CO2 were three times higher in NA (1,022 genes) compared with CA (372 genes) Norstar. The most striking effect was the down-regulation of genes involved in the plant defense responses in NA Norstar. In contrast, cold acclimation reversed this down-regulation due to the cold induction of genes involved in plant pathogenesis resistance; and cellular and chloroplast protection. These results suggest that elevated CO2 has less impact on plant performance and productivity in cold-adapted winter hardy plants in the northern climates compared with warmer environments. Selection for cereal cultivars with constitutively higher expression of biotic stress defense genes may be necessary under elevated CO2 during the warm growth period and in warmer climates. PMID:23969557

  20. Long-Term Trends in High Elevation Tropospheric Ozone in the Northeastern US: Implications for Ozone Uptake in Red Spruce-Dominated Ecosystems

    NASA Astrophysics Data System (ADS)

    Bergweiler, C.

    2009-12-01

    Despite state and national air quality initiatives ground-level ozone continues to affect vegetation in natural, urban, and agro-ecosystems, causing a variety of damage to susceptible crops, trees, herbs and shrubs. Although the summer of 2009 experienced a (positive) air quality anomaly in the Northeast, at least 56 elevated ozone events occurred in 2008 between April and September in New England alone. Summertime ozone persistence at remote higher elevations is characterized by well-documented level diel (nocturnally stable) exposures, versus the typical diurnal formation and fate observed at lower elevations. Primary goals of this study were i) to assess ozone exposure trends based on up to 18 years of archival data and ii) to define how controlling mechanisms of ozone uptake differ for red spruce in alpine environments from those at lower elevation. Preliminary findings show that air quality at surveyed high elevation sites shows neither improvement nor deterioration at either southern or northern New England locations. A substantial proportion of ozone distribution in the highest concentration ranges (≥80 ppb) occurs nocturnally at higher elevations, often exceeding valley locations. Commonly applied cumulative ozone concentration exposure metrics AOT40 (EU) and SUM60 (US EPA) were calculated and it was determined that nighttime ozone exposures can exceed daytime exposures in southern New England. Monthly average exposures tended to be highest in spring, but it is unclear if physiological age of red spruce saplings is protective against ozone injury, i.e. current-year needles have not entered the phase of seasonal maximum stomatal conductance (gmax).

  1. Representative Atmospheric Plume Development for Elevated Releases

    SciTech Connect

    Eslinger, Paul W.; Lowrey, Justin D.; McIntyre, Justin I.; Miley, Harry S.; Prichard, Andrew W.

    2014-02-01

    An atmospheric explosion of a low-yield nuclear device will produce a large number of radioactive isotopes, some of which can be measured with airborne detection systems. However, properly equipped aircraft may not arrive in the region where an explosion occurred for a number of hours after the event. Atmospheric conditions will have caused the radioactive plume to move and diffuse before the aircraft arrives. The science behind predicting atmospheric plume movement has advanced enough that the location of the maximum concentrations in the plume can be determined reasonably accurately in real time, or near real time. Given the assumption that an aircraft can follow a plume, this study addresses the amount of atmospheric dilution expected to occur in a representative plume as a function of time past the release event. The approach models atmospheric transport of hypothetical releases from a single location for every day in a year using the publically available HYSPLIT code. The effective dilution factors for the point of maximum concentration in an elevated plume based on a release of a non-decaying, non-depositing tracer can vary by orders of magnitude depending on the day of the release, even for the same number of hours after the release event. However, the median of the dilution factors based on releases for 365 consecutive days at one site follows a power law relationship in time, as shown in Figure S-1. The relationship is good enough to provide a general rule of thumb for estimating typical future dilution factors in a plume starting at the same point. However, the coefficients of the power law function may vary for different release point locations. Radioactive decay causes the effective dilution factors to decrease more quickly with the time past the release event than the dilution factors based on a non-decaying tracer. An analytical expression for the dilution factors of isotopes with different half-lives can be developed given the power law expression

  2. Long-term exposure to elevated CO2 enhances plant community stability by suppressing dominant plant species in a mixed-grass prairie

    NASA Astrophysics Data System (ADS)

    Zelikova, Tamara Jane; Blumenthal, Dana M.; Williams, David G.; Souza, Lara; LeCain, Daniel R.; Morgan, Jack; Pendall, Elise

    2014-10-01

    Climate controls vegetation distribution across the globe, and some vegetation types are more vulnerable to climate change, whereas others are more resistant. Because resistance and resilience can influence ecosystem stability and determine how communities and ecosystems respond to climate change, we need to evaluate the potential for resistance as we predict future ecosystem function. In a mixed-grass prairie in the northern Great Plains, we used a large field experiment to test the effects of elevated CO2, warming, and summer irrigation on plant community structure and productivity, linking changes in both to stability in plant community composition and biomass production. We show that the independent effects of CO2 and warming on community composition and productivity depend on interannual variation in precipitation and that the effects of elevated CO2 are not limited to water saving because they differ from those of irrigation. We also show that production in this mixed-grass prairie ecosystem is not only relatively resistant to interannual variation in precipitation, but also rendered more stable under elevated CO2 conditions. This increase in production stability is the result of altered community dominance patterns: Community evenness increases as dominant species decrease in biomass under elevated CO2. In many grasslands that serve as rangelands, the economic value of the ecosystem is largely dependent on plant community composition and the relative abundance of key forage species. Thus, our results have implications for how we manage native grasslands in the face of changing climate.

  3. Long-term exposure to elevated CO2 enhances plant community stability by suppressing dominant plant species in a mixed-grass prairie

    PubMed Central

    Zelikova, Tamara Jane; Blumenthal, Dana M.; Williams, David G.; Souza, Lara; LeCain, Daniel R.; Morgan, Jack; Pendall, Elise

    2014-01-01

    Climate controls vegetation distribution across the globe, and some vegetation types are more vulnerable to climate change, whereas others are more resistant. Because resistance and resilience can influence ecosystem stability and determine how communities and ecosystems respond to climate change, we need to evaluate the potential for resistance as we predict future ecosystem function. In a mixed-grass prairie in the northern Great Plains, we used a large field experiment to test the effects of elevated CO2, warming, and summer irrigation on plant community structure and productivity, linking changes in both to stability in plant community composition and biomass production. We show that the independent effects of CO2 and warming on community composition and productivity depend on interannual variation in precipitation and that the effects of elevated CO2 are not limited to water saving because they differ from those of irrigation. We also show that production in this mixed-grass prairie ecosystem is not only relatively resistant to interannual variation in precipitation, but also rendered more stable under elevated CO2 conditions. This increase in production stability is the result of altered community dominance patterns: Community evenness increases as dominant species decrease in biomass under elevated CO2. In many grasslands that serve as rangelands, the economic value of the ecosystem is largely dependent on plant community composition and the relative abundance of key forage species. Thus, our results have implications for how we manage native grasslands in the face of changing climate. PMID:25313034

  4. Long-term growth of soybean and maize at elevated [CO2] under free-air concentration enrichment (FACE) reduces soil moisture depletion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stomatal conductance (gs) is lower when plants are grown at elevated [CO2] compared to ambient [CO2]. This is often assumed to reduce plant water use and ameliorate water stress by conserving soil moisture. However, under field conditions canopy size, canopy structure, microclimate and fluxes of wat...

  5. Steeper increases in body mass index during childhood correlate with blood pressure elevation in adolescence: a long-term follow-up study in a Japanese community.

    PubMed

    Kuwahara, Erika; Asakura, Keiko; Nishiwaki, Yuji; Komatsu, Hirokazu; Nakazawa, Akemi; Ushiku, Hideo; Maejima, Fumio; Nishigaki, Yoshio; Hasegawa, Tomonobu; Okamura, Tomonori; Takebayashi, Toru

    2014-02-01

    The aim of this study was to clarify the relationship between long-term changes in body mass index (BMI) during childhood and adolescent blood-pressure levels in a general Japanese population. We used health report data from 900 Japanese children between 1983 and 2007. After adjusting for baseline BMI and other confounding factors multivariate linear regression analyses were performed to examine the relationship between changes in BMI (ΔBMI) over a 6-year period (6-12 years) and blood pressure once children reached ages 14 or 15. Sub-group analyses were also performed to ascertain the relationship between ΔBMI and blood pressure at 9th grade for children who had been in the bottom BMI tertile at 1st grade. Endpoint blood-pressure levels in boys (systolic and diastolic) and girls (systolic) from the group whose BMIs increased the most were significantly higher than those from the group whose BMIs increased the least (P<0.05, analysis of variance). After adjustment for baseline BMI and school-entrance year, the former group showed higher blood pressure at the endpoint than the latter (P<0.05, multiple regression analysis). Further adjustment for baseline blood pressure also showed similar results in a combined-sex analysis (n=592). Higher ΔBMI was associated with higher SBP9 even in children whose BMI was in the lowest tertile at baseline after adjustment for sex and school-entrance year (P=0.02, multiple regression analysis). Steeper BMI increases during primary school lead to adolescent increases in blood pressure even if baseline BMI is low. Growth during childhood should be carefully managed. PMID:24026043

  6. Long-term untreated streptozotocin-diabetes leads to increased expression and elevated activity of prostaglandin H2 synthase in blood platelets.

    PubMed

    Siewiera, Karolina; Kassassir, Hassan; Talar, Marcin; Wieteska, Lukasz; Watala, Cezary

    2016-05-01

    In diabetes-related states of chronic hyperglycaemia elevated concentrations of glucose may alter the functioning of platelet enzymes involved in arachidonic acid metabolism, including prostaglandin H2 synthase (cyclooxygenase) (PGHS, COX). Therefore, the principal aim of this study was to assess the effects of experimental chronic hyperglycaemia on platelet PGHS-1 (COX-1) expression and activity. Blood platelet activation and reactivity were assessed in Sprague-Dawley rats with the 5-month streptozotocin (STZ) diabetes. The PGHS-1 abundance in platelets was evaluated with flow cytometry and Western blotting, while its activity monitored using a high resolution respirometry and the peroxidase fluorescent assay. The production of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) in platelets were assayed immunoenzymatically. Circulating platelets from diabetic were characterised by increased size, elevated 'priming' and altered reactivity, compared to non-diabetic animals. Both Western blot analysis and flow cytometry revealed significantly elevated expressions of platelet PGHS-1 in STZ-diabetic rats (p < 0.05). We also observed significantly elevated platelet PGHS-1-related arachidonic acid metabolism in diabetic vs. non-diabetic animals, with the use of polarographic (p < 0.05) and total activity assay (p < 0.001). Such increases were accompanied by the elevated production of PGE2 (p < 0.001) and TXB2 (p < 0.05) in diabetic animals. The increased PGHS-1-dependent oxygen consumption and the total activity of PGHS-1 in diabetic animals remained very significant (p < 0.001) also upon adjusting for blood platelet PGHS-1 abundance. Therefore, our results further contribute to the explanation of the increased metabolism of arachidonic acid observed in diabetes. PMID:26325148

  7. Long-term stability of peneplains and landscape evolution in southern Tibet inferred from field data, cosmogenic nuclides, and digital elevation models

    NASA Astrophysics Data System (ADS)

    Strobl, M.; Hetzel, R.; Ding, L.; Zhang, L.

    2010-05-01

    Peneplains constitute a widespread and well developed geomorphic element on the Tibetan Plateau, nevertheless little is known about their formation and the subsequent landscape evolution. In southern Tibet, north of Nam Co (~31° 20'N, 90° E), a particularly well-preserved peneplain occurs at an elevation of ~5350 m in Cretaceous granitoids. The main planation surface has been incised by small streams that formed additional small low-relief surfaces at lower elevations. Fluvial incision of the main peneplain has generated a local relief of up to ~700 m. The progressive incision has led to hillslope gradients that increase with decreasing elevation, i.e. from the main peneplain at ~5350 m down to the current base level at ~4650 m, as revealed by field observations and the analysis of digital elevation model. In order to quantify the landscape evolution of the peneplain region we determined local and catchment-wide erosion rates from the concentration of in situ-produced cosmogenic 10Be. Local erosion rates on the main peneplain and the low-relief bedrock surfaces at lower elevation range from 6 to 12 m Ma-1 and indicate that the geomorphic surfaces are stable over long periods of time. Spatially integrated erosion rates of small river systems that are incising and eroding headwards into the main peneplain are only slightly higher and range from 11 to 18 m Ma-1. Even if river incision has proceeded at a rate that is 2-4 times higher than the catchment-wide erosion rates, i.e. at 30 to 60 m Ma-1, it would take about 10 to 20 Ma to generate the local relief of ~700 m observed today. This demonstrates that the major peneplain is a very stable geomorphic element with a minimum age of 10 to 20 Ma and that the landscape in the region has barely been modified by erosion in the last millions of years.

  8. Long-term observations of 14C-based atmospheric fossil fuel CO2 (FFCO2) and the CO/FFCO2 ratio in the Heidelberg urban environment

    NASA Astrophysics Data System (ADS)

    Levin, Ingeborg; Hammer, Samuel; Kromer, Bernd

    2013-04-01

    smaller contribution of traffic to the emissions. Our results clearly show that statistical emissions inventories, or at least the ratios of emissions and their changes, can be reliably verified on the local to regional scale by careful long term atmospheric observations. A temporal change of the CO/FFCO2 emission ratio has, however, also implications for the use of CO as surrogate tracer for high-resolution fossil fuel CO2 estimates (e.g. Levin & Karstens, Tellus 59B, 2007): Without ongoing 14C calibration of the CO/FFCO2 ratio, decadal trends in CO-based fossil fuel CO2 estimates can be largely biased by up to 20-30%. The research leading to these results has received funding from the European Community's Sixth and Seventh Framework Programs in the CarboEurope-IP (GOCE-CT-2003-505572) and ICOS Preparatory Phase (211574) projects.

  9. Ultra-acute increase in blood glucose during prehospital phase is associated with worse short-term and long-term survival in ST-elevation myocardial infarction

    PubMed Central

    2014-01-01

    Background The current study was to investigate the blood glucose changes in ultra-acute phase in patients with ST-elevation myocardial infarction (STEMI) and its associations with patient outcome. Methods This study was a retrospective population-based observational study utilizing prospectively collected registry data complemented with laboratory data. All adult patients with STEMI treated by emergency medical services (EMS) in the city of Helsinki from January 2006 to December 2010 were included in the study. Both prehospital and hospital admission glucose values were available from 152 (32%) of all STEMI patients (n = 469). Results Change in blood glucose from prehospital phase to emergency department admission was significantly higher in non-survivors within 30 days compared to survivors (+1.2 ± 5.1 vs. -0.3 ± 2.4 mmol/l [mean ± SD], P = 0.03). Furthermore, the 3-year survival rate was significantly lower in patients with an evident (≥2 mmol/l) rise in blood glucose (P = 0.02). In patients with impaired left ventricle function (best ejection fraction < 40%), blood glucose increased more compared to patients without it (1.2 ± 2.9 vs. 0.4 ± 2.7 mmol/l, P = 0.01). Increase in glucose was correlated with peak myocardial creatinine kinase (r = 0.17, P = 0.04) as a marker of increased size of infarct, but not with glycosylated haemoglobin A1C as a marker of chronic hyperglycaemia (r = −0.12, P = 0.27). Conclusions In patients with STEMI, ultra-acute hyperglycaemia during prehospital phase is associated with increased mortality, impaired cardiac function and increased size of infarct. PMID:24886984

  10. Long-term low latitude and high elevation cosmogenic (3) He production rate inferred from a new calibration site in hyperarid Northern Chile

    NASA Astrophysics Data System (ADS)

    Delunel, Romain; Blard, Pierre-Henri; Martin, Léo; Nomade, Sébastien; Schlunegger, Fritz

    2016-04-01

    The rates at which the cosmogenic nuclides are produced at the surface of the Earth are usually inferred from independently dated geological calibration sites. Despite available calibration sites for cosmogenic 3He are relatively abundant, they are clustered both in space (mid to high latitudes) and time (ca. 5-20 ka), which prevents qualitative assessments and further developments of production models used to convert cosmogenic 3He concentrations into exposure ages and/or denudation rates. Accordingly, more low latitude calibration sites with exposure durations significantly longer than 20 ka are required. Here we present the results from a new geological calibration site located in northern Chile were several samples have been collected on the surface of a well-preserved lava flow for both 40Ar/39Ar dating and cosmogenic 3He analyzes. Cosmogenic 3He concentrations were converted to a sea level high latitude (SLHL) reference position using the eruption age determined for the lava flow from the Ar measurements, together with scaling frameworks that include varying combinations of geographic spatialization schemes, atmosphere models and geomagnetic field reconstructions. The inferred SLHL cosmogenic 3He production rates are consistent with the most recent estimates available from the literature and thus attest to the robustness of both the most widely used and recently developed scaling models. Finally, we use the same scaling frameworks to re-evaluate the mean global-scale cosmogenic 3He production rate in olivine and pyroxene minerals using an updated compilation of previously published calibration datasets.

  11. Long-term Academic and Career Impacts of Undergraduate Research: Diverse Pathways to Geoscience Careers Following a Summer Atmospheric Science Research Internship

    NASA Astrophysics Data System (ADS)

    Trott, C. D.; Sample McMeeking, L. B.; Boyd, K.; Bowker, C.

    2015-12-01

    Research experiences for undergraduates (REU) have been shown to support the success of STEM undergraduates through improving their research skills, ability to synthesize knowledge, and personal and professional development, all while socializing them into the nature of science. REUs are further intended to support STEM career choice and professional advancement, and have thus played a key role in diversity efforts. Recruiting and retaining diverse students in STEM through REUs is of particular importance in the geosciences, where women and ethnic minorities continue to be significantly underrepresented. However, few studies have examined the long-term impacts of these REUs on students' academic and career trajectories. Further, those that do exist primarily study the experiences of current graduate students, scientists, and faculty members—that is, those who have already persisted—which overlooks the multiple academic and career paths REU students might follow and may preclude a thorough examination of REUs' diversity impacts. In this long-term retrospective study of the academic and career impacts of a REU program at a large Western U.S. research university, we interviewed 17 former REU participants on their expectations prior to their REU participation, their experiences during the REU, the immediate outcomes from the experience, and its long-term impacts on their academic and career choices. To address gaps in the existing literature on REU impacts, we purposively sampled students who have taken a variety of educational and career paths, including those not engaged in science research. Despite varied trajectories, the majority of the students we interviewed have persisted in the geosciences and attest to the REU's profound impact on their career-related opportunities and choices. This presentation describes students' diverse STEM pathways and discusses how students' REU expectations, experiences, and immediate outcomes continued to make an impact long-term.

  12. Cold acclimation and BnCBF17-over-expression enhance photosynthetic performance and energy conversion efficiency during long-term growth of Brassica napus under elevated CO2 conditions.

    PubMed

    Dahal, Keshav; Gadapati, Winona; Savitch, Leonid V; Singh, Jas; Hüner, Norman P A

    2012-11-01

    The effects of cold acclimation and long-term elevated CO(2) on photosynthetic performance of wild-type (WT) and BnCBF17-over-expressing line of Brassica napus cv. Westar (BnCBF17-OE) grown at either 20/16 °C (non-acclimated) or 5/5 °C (cold acclimated) and at either ambient (380 μmol C mol(-1)) or elevated (700 μmol C mol(-1)) CO(2) were studied. Compared with non-acclimated WT, the BnCBF17-OE grown at 20 °C mimicked the effects of cold acclimation on WT B. napus with respect to compact dwarf phenotype and increased rates of light-saturated CO(2) assimilation and photosynthetic electron transport. This was associated with enhanced energy conversion efficiency into biomass as assessed by decreased excitation pressure coupled to decreased dependence on non-photochemical energy dissipation for a given irradiance. Growth at elevated CO(2) decreased the light and CO(2)-saturated rates of photosynthesis by 30 % for non-acclimated WT relative to growth at ambient CO(2). This was associated with inhibition in electron transport rates (20 %), decrease in amount of rbcL (35 %) and cytosolic FBPase (70 %) and increased excitation pressure and non-photochemical quenching in elevated versus ambient CO(2)-grown non-acclimated WT. In contrast, light and CO(2)-saturated rates of photosynthesis, electron transport, excitation pressure, non-photochemical quenching and levels of rbcL, cytosolic FBPase and Lhcb1 were insensitive to growth under elevated CO(2) in BnCBF17-OE and cold-acclimated WT. Thus, BnCBF17-over-expression and cold acclimation maintain enhanced energy conversion efficiency and reduced sensitivity to feedback-limited photosynthesis during long-term growth of B. napus under elevated CO(2). Our results indicated that CBFs transcription factors regulate not only freezing tolerance but also has major whole plant effects. PMID:22847022

  13. Long-term testing

    NASA Astrophysics Data System (ADS)

    Ferber, M.; Graves, G. A., Jr.

    Land-based gas turbines are significantly different from automotive gas turbines in that they are designed to operate for 50,000 h or greater (compared to 5,000-10,000 h). The primary goal of this research is to determine the long-term survivability of ceramic materials for industrial gas turbine applications. Research activities in this program focus on the evaluation of the static tensile creep and stress rupture (SR) behavior of three commercially available structural ceramics which have been identified by the gas turbine manufacturers as leading candidates for use in industrial gas turbines. For each material investigated, a minimum of three temperatures and four stresses will be used to establish the stress and temperature sensitivities of the creep and SR behavior. Because existing data for many candidate structural ceramics are limited to testing times less than 2,000 h, this program will focus on extending these data to times on the order of 10,000 h, which represents the lower limit of operating time anticipated for ceramic blades and vanes in gas turbine engines. A secondary goal of the program will be to investigate the possibility of enhancing life prediction estimates by combining interrupted tensile SR tests and tensile dynamic fatigue tests in which tensile strength is measured as a function of stressing rate. The third goal of this program will be to investigate the effects of water vapor upon the SR behavior of the three structural ceramics chosen for the static tensile studies by measuring the flexural strength as a function of stressing rate at three temperatures.

  14. Long-term testing

    SciTech Connect

    Ferber, M.; Graves, G.A. Jr.

    1994-12-31

    Land-based gas turbines are significantly different from automotive gas turbines in that they are designed to operate for 50,000 h or greater (compared to 5,000--10,000 h). The primary goal of this research is to determine the long-term survivability of ceramic materials for industrial gas turbine applications. Research activities in this program focus on the evaluation of the static tensile creep and stress rupture (SR) behavior of three commercially available structural ceramics which have been identified by the gas turbine manufacturers as leading candidates for use in industrial gas turbines. For each material investigated, a minimum of three temperatures and four stresses will be used to establish the stress and temperature sensitivities of the creep and SR behavior. Because existing data for many candidate structural ceramics are limited to testing times less than 2,000 h, this program will focus on extending these data to times on the order of 10,000 h, which represents the lower limit of operating time anticipated for ceramic blades and vanes in gas turbine engines. A secondary goal of the program will be to investigate the possibility of enhancing life prediction estimates by combining interrupted tensile SR tests and tensile dynamic fatigue tests in which tensile strength is measured as a function of stressing rate. The third goal of this program will be to investigate the effects of water vapor upon the SR behavior of the three structural ceramics chosen for the static tensile studies by measuring the flexural strength as a function of stressing rate at three temperatures.

  15. Initial Examination of the Long Term Thermosphere Changes As Seen in the Whole Atmosphere Community Climate Model - eXtended (WACCM-X) J. M. McInerney, L. Qian, and H.-L Liu

    NASA Astrophysics Data System (ADS)

    McInerney, J. M.; Qian, L.; Liu, H.

    2013-12-01

    It has been over two decades since the projection that, not only will the human induced increase in atmospheric CO2 produce a warming in the troposphere, it will also produce a cooling in the middle to upper atmosphere into the 21st century with significant consequences. The thermospheric density decrease associated with this projected upper atmosphere cooling due to greenhouse gases has been confirmed by observations, in particular satellite drag measurements, and by various modeling studies. Recent studies also suggest potential impacts from the lower atmosphere on thermosphere dynamics such as atmospheric thermal tides and gravity waves. With the current advance of whole atmosphere climate models which extend from the ground through the thermosphere, it is now possible to include effects of these and other lower atmosphere processes in modeling studies of long term thermospheric changes. One such whole atmosphere model under development at the National Center for Atmospheric Research (NCAR) is the Whole Atmosphere Community Climate Model - eXtended (WACCM-X). WACCM-X is a self consistent climate model extending from the ground to approximately 500 kilometers and is based on the Whole Atmosphere Community Climate Model (WACCM) / Community Atmosphere Model (CAM) component of the Community Earth System Model (CESM). Although an interactive ionosphere module is not complete, the globally averaged structure of thermosphere temperature and neutral species from WACCM-X are reasonable compared with the NCAR global mean model. In this study, we will examine a transient WACCM-X simulation from 1955 to 2005 with realistic tropospheric CO2 input and solar and geomagnetic forcing. The preliminary study will focus on the long term changes in the thermosphere from this simulation, in particular the secular changes of thermosphere neutral density and temperature due to anthropogenic forcing.

  16. Building long-term and high spatio-temporal resolution precipitation and air temperature reanalyses by mixing local observations and global atmospheric reanalyses: the ANATEM method

    NASA Astrophysics Data System (ADS)

    Kuentz, A.; Mathevet, T.; Gailhard, J.; Hingray, B.

    2015-01-01

    Improving the understanding of past climatic or hydrologic variability has received a large attention in different fields of geosciences, such as glaciology, dendrochronology, sedimentology or hydrology. Based on different proxies, each research community produces different kind of climatic or hydrologic reanalyses, at different spatio-temporal scales and resolution. When considering climate or hydrology, numerous studies aim at characterising variability, trends or breaks using observed time-series of different regions or climate of world. However, in hydrology, these studies are usually limited to reduced temporal scale (mainly few decades, seldomly a century) because they are limited to observed time-series, that suffers from a limited spatio-temporal density. This paper introduces a new model, ANATEM, based on a combination of local observations and large scale climatic informations (such as 20CR Reanalysis). This model allow to build long-term air temperature and precipitation time-series, with a high spatio-temporal resolution (daily time-step, few km2). ANATEM was tested on the air temperature and precipitation time-series of 22 watersheds situated on the Durance watershed, in the french Alps. Based on a multi-criteria and multi-scale diagnostic, the results show that ANATEM improves the performances of classical statistical models. ANATEM model have been validated on a regional level, improving spatial homogeneity of performances and on independent long-term time-series, being able to capture the regional low-frequency variabilities over more than a century (1883-2010).

  17. Warming reduces carbon losses from grassland exposed to elevated atmospheric carbon dioxide.

    PubMed

    Pendall, Elise; Heisler-White, Jana L; Williams, David G; Dijkstra, Feike A; Carrillo, Yolima; Morgan, Jack A; Lecain, Daniel R

    2013-01-01

    The flux of carbon dioxide (CO2) between terrestrial ecosystems and the atmosphere may ameliorate or exacerbate climate change, depending on the relative responses of ecosystem photosynthesis and respiration to warming temperatures, rising atmospheric CO2, and altered precipitation. The combined effect of these global change factors is especially uncertain because of their potential for interactions and indirectly mediated conditions such as soil moisture. Here, we present observations of CO2 fluxes from a multi-factor experiment in semi-arid grassland that suggests a potentially strong climate - carbon cycle feedback under combined elevated [CO2] and warming. Elevated [CO2] alone, and in combination with warming, enhanced ecosystem respiration to a greater extent than photosynthesis, resulting in net C loss over four years. The effect of warming was to reduce respiration especially during years of below-average precipitation, by partially offsetting the effect of elevated [CO2] on soil moisture and C cycling. Carbon losses were explained partly by stimulated decomposition of soil organic matter with elevated [CO2]. The climate - carbon cycle feedback observed in this semiarid grassland was mediated by soil water content, which was reduced by warming and increased by elevated [CO2]. Ecosystem models should incorporate direct and indirect effects of climate change on soil water content in order to accurately predict terrestrial feedbacks and long-term storage of C in soil. PMID:23977180

  18. Elevated atmospheric carbon dioxide increases soil carbon

    SciTech Connect

    Norby, Richard J; Jastrow, Julie D; Miller, Michael R; Matamala, Roser; Boutton, Thomas W; Rice, Charles W; Owensby, Clenton E

    2005-01-01

    In a study funded by the U.S. Department of Energy's Office of Science, researchers from Argonne and Oak Ridge National Laboratories and Kansas State and Texas A&M Universities evaluated the collective results of earlier studies by using a statistical procedure called meta-analysis. They found that on average elevated CO2 increased soil carbon by 5.6 percent over a two to nine year period. They also measured comparable increases in soil carbon for Tennessee deciduous forest and Kansas grassland after five to eight years of experimental exposure to elevated CO2.

  19. Ramipril and Losartan Exert a Similar Long-Term Effect upon Markers of Heart Failure, Endogenous Fibrinolysis, and Platelet Aggregation in Survivors of ST-Elevation Myocardial Infarction: A Single Centre Randomized Trial

    PubMed Central

    Marinšek, Martin; Sinkovič, Andreja

    2016-01-01

    Introduction. Blocking the renin-angiotensin-aldosterone system in ST-elevation myocardial infarction (STEMI) patients prevents heart failure and recurrent thrombosis. Our aim was to compare the effects of ramipril and losartan upon the markers of heart failure, endogenous fibrinolysis, and platelet aggregation in STEMI patients over the long term. Methods. After primary percutaneous coronary intervention (PPCI), 28 STEMI patients were randomly assigned ramipril and 27 losartan, receiving therapy for six months with dual antiplatelet therapy (DAPT). We measured N-terminal proBNP (NT-proBNP), ejection fraction (EF), plasminogen-activator-inhibitor type 1 (PAI-1), and platelet aggregation by closure times (CT) at the baseline and after six months. Results. Baseline NT-proBNP ≥ 200 pmol/mL was observed in 48.1% of the patients, EF < 55% in 49.1%, and PAI-1 ≥ 3.5 U/mL in 32.7%. Six-month treatment with ramipril or losartan resulted in a similar effect upon PAI-1, NT-proBNP, EF, and CT levels in survivors of STEMI, but in comparison to control group, receiving DAPT alone, ramipril or losartan treatment with DAPT significantly increased mean CT (226.7 ± 80.3 sec versus 158.1 ± 80.3 sec, p < 0.05). Conclusions. Ramipril and losartan exert a similar effect upon markers of heart failure and endogenous fibrinolysis, and, with DAPT, a more efficient antiplatelet effect in long term than DAPT alone. PMID:27064499

  20. Long-term environmental stewardship.

    SciTech Connect

    Nagy, Michael David

    2010-08-01

    The purpose of this Supplemental Information Source Document is to effectively describe Long-Term Environmental Stewardship (LTES) at Sandia National Laboratories/New Mexico (SNL/NM). More specifically, this document describes the LTES and Long-Term Stewardship (LTS) Programs, distinguishes between the LTES and LTS Programs, and summarizes the current status of the Environmental Restoration (ER) Project.

  1. Impacts of Elevated Atmospheric CO 2 and O 3 on Paper Birch ( Betula papyrifera ): Reproductive Fitness

    DOE PAGESBeta

    Darbah, Joseph N. T.; Kubiske, Mark E.; Nelson, Neil; Oksanen, Elina; Vaapavuori, Elina; Karnosky, David F.

    2007-01-01

    Atmospheric CO 2 and tropospheric O 3 are rising in many regions of the world. Little is known about how these two commonly co-occurring gases will affect reproductive fitness of important forest tree species. Here, we report on the long-term effects of CO 3 and O 3 for paper birch seedlings exposed for nearly their entire life history at the Aspen FACE (Free Air Carbon Dioxide Enrichment) site in Rhinelander, WI. Elevated CO 2 increased both male and female flower production, while elevated O 3 increased female flower production compared to trees in control rings. Interestingly, very little floweringmore » has yet occurred in combined treatment. Elevated CO 2 had significant positive effect on birch catkin size, weight, and germination success rate (elevated CO 2 increased germination rate of birch by 110% compared to ambient CO 2 concentrations, decreased seedling mortality by 73%, increased seed weight by 17%, increased root length by 59%, and root-to-shoot ratio was significantly decreased, all at 3 weeks after germination), while the opposite was true of elevated O 3 (elevated O 3 decreased the germination rate of birch by 62%, decreased seed weight by 25%, and increased root length by 15%). Under elevated CO 2 , plant dry mass increased by 9 and 78% at the end of 3 and 14 weeks, respectively. Also, the root and shoot lengths, as well as the biomass of the seedlings, were increased for seeds produced under elevated CO 2 , while the reverse was true for seedlings from seeds produced under the elevated O 3 . Similar trends in treatment differences were observed in seed characteristics, germination, and seedling development for seeds collected in both 2004 and 2005. Our results suggest that elevated CO 2 and O 3 can dramatically affect flowering, seed production, and seed quality of paper birch, affecting reproductive fitness of this species.« less

  2. Presynaptic long-term plasticity

    PubMed Central

    Yang, Ying; Calakos, Nicole

    2013-01-01

    Long-term synaptic plasticity is a major cellular substrate for learning, memory, and behavioral adaptation. Although early examples of long-term synaptic plasticity described a mechanism by which postsynaptic signal transduction was potentiated, it is now apparent that there is a vast array of mechanisms for long-term synaptic plasticity that involve modifications to either or both the presynaptic terminal and postsynaptic site. In this article, we discuss current and evolving approaches to identify presynaptic mechanisms as well as discuss their limitations. We next provide examples of the diverse circuits in which presynaptic forms of long-term synaptic plasticity have been described and discuss the potential contribution this form of plasticity might add to circuit function. Finally, we examine the present evidence for the molecular pathways and cellular events underlying presynaptic long-term synaptic plasticity. PMID:24146648

  3. Zooplankton long-term changes in the NW Mediterranean Sea: Decadal periodicity forced by winter hydrographic conditions related to large-scale atmospheric changes?

    NASA Astrophysics Data System (ADS)

    García-Comas, Carmen; Stemmann, Lars; Ibanez, Frédéric; Berline, Léo; Mazzocchi, Maria Grazia; Gasparini, Stéphane; Picheral, Marc; Gorsky, Gabriel

    2011-09-01

    Copepod, chaetognath, decapod larva, siphonophore and jellyfish monthly abundances, from 1974 to 2003 at Point B (northwestern Mediterranean), were obtained with the ZooScan. Principal component analysis (PCA) was performed on zooplankton, and another PCA on local environment. Almost-decadal periods (1974-1982, 1983-1991, 1992-1999, and 2000-2003) were distinguished in the 1st PC of zooplankton, and that of local environment (1974-1980, 1981-1991, 1992-1998, and 1999-2003). The 1st PC of local environment was correlated with winter North Atlantic Oscillation (NAO) until early 1990s. In early 1980s, all groups increased and the majority of the decade abundances were above the long-term average for most groups. In the 1990s, all decreased, and in early 2000s they increased. This synchrony suggests bottom-up control as main mechanism structuring these groups. The 1980s were characterized by low winter temperature and high salinity. We hypothesize that phytoplankton production was favored during that decade due to increased nutrient uprise to surface by strong winter vertical mixing. In the 1990s salinity decreased probably to the detriment of vertical mixing and carrying capacity of the system. These results stress the role of salinity as physical forcing on water-column stability, in the NW Mediterranean, and the importance of winter conditions to determine the state of pelagic ecosystems.

  4. Long-term decrease of atmospheric test {sup 137}Cs in the soil-prairie plant-milk pathway in southern Chile

    SciTech Connect

    Schuller, P. Ellies, A.; Handl, J.

    1998-07-01

    The time dependency of nuclear test {sup 137}Cs in soil, prairie plants, and milk was observed on pastures of seven dairy farms in the 10th Region, Chile, from 1982 to 1997, without any appreciable deposition of radioactive fallout after 1983. Whereas the {sup 137}Cs concentration in the soil decreased at a rate close to that of the radionuclide`s physical decay during the whole observation period, the rate of decrease of the {sup 137}Cs concentration in the prairie plants and in the milk, having been very rapid between 1982--1990, became slower between 1991--1997. The effective half-lives of the concentration in plants were found to be 5.6 y and 12 y during the first and second observation periods, respectively. Similar half-lives of 5.5 y and 13 y were found for the concentration decline in milk during each period. These data clearly demonstrate a reduction in the long-term decrease of the {sup 137}Cs plant uptake, and consequently in the decrease of the {sup 137}Cs concentration in milk, resulting from a decline of {sup 137}Cs availability for prairie plants in the Hapludand soils over the whole 15-y observation period.

  5. Evaluation of a dynamically downscaled atmospheric reanalyse in the prospect of forcing long term simulations of the ocean circulation in the Gulf of Lions

    NASA Astrophysics Data System (ADS)

    Langlais, C.; Barnier, B.; Molines, J. M.; Fraunié, P.; Jacob, D.; Kotlarski, S.

    The paper evaluates atmospheric reanalysis as possible forcing of model simulations of the ocean circulation inter-annual variability in the Gulf of Lions in the Western Mediterranean Sea between 1990 and 2000. The sensitivity of the coastal atmospheric patterns to the model resolution is investigated using the REMO regional climate model (18 km, 1 h), and the recent global atmospheric reanalysis ERA40 (125 km, 6 h). At scales from a few years to a few days, both atmospheric data sets exhibit a very similar weather, and agreement between REMO and ERA40 is especially good on the seasonal cycle and at the daily variability scale. At smaller scales, REMO reproduces more realistic spatio-temporal patterns in the ocean forcing: specific wind systems, particular atmospheric behaviour on the shelf, diurnal cycle, sea-breeze. Ocean twin experiments (1990-1993) clearly underline REMO skills to drive dominant oceanic processes in this microtidal area. Finer wind patterns induce a more realistic circulation and hydrology of the shelf water: unique shelf circulation, upwelling, temperature and salinity exchanges at the shelf break. The hourly sampling of REMO introduces a diurnal forcing which enhances the behaviour of the ocean mixed layer. In addition, the more numerous wind extremes modify the exchanges at the shelf break: favouring the export of dense shelf water, enhancing the mesoscale variability and the interactions of the along slope current with the bathymetry.

  6. The Impact of SYNTAX Score of Non-Infarct-Related Artery on Long- Term Outcome among Patients with Acute ST Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

    PubMed Central

    Su, Min-I; Tsai, Cheng-Ting; Yeh, Hung-I; Chen, Chun-Yen

    2014-01-01

    Objective We investigated the impact of the severity of stenosis in a non-infarct-related artery (IRA) on the long-term prognosis of patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Methods Three hundred one consecutive patients (age: 59.7 ± 13.2 years, 85.5% men) underwent primary PCI during 2009–2012. Receiver operating characteristic curve analysis found the optimal cutoff for non-IRA SYNTAX score (SS) to be 2.5. We divided the patients into two groups according to this cutoff value. Results By multivariable analysis, non-IRA SS (≥2.5) was an independent predictor of major adverse cardiac events (hazard ratio [HR]: 2.15, 95% confidence interval [CI]: 1.21–3.79, P  =  0.008) and all-cause mortality (HR: 3.49, 95% CI: 1.13–10.8, P  =  0.03). However, the prediction of cardiovascular mortality had only borderline significance (HR: 3.29, 95% CI: 0.90–12.08, P  =  0.07). Conclusion STEMI patients treated with primary PCI and moderate to severe non-IRA stenosis (SS ≥2.5) have more subsequent cardiac events. Those populations should be treated with more aggressive preventive and medical management. PMID:25303079

  7. Long term complications of diabetes

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000327.htm Long term complications of diabetes To use the sharing ... sores and infections. If it goes on too long, your toes, foot, or leg may need to ...

  8. Abdominal Pain, Long-Term

    MedlinePlus

    MENU Return to Web version Abdominal Pain, Long-term See complete list of charts. Ongoing or recurrent abdominal pain, also called chronic pain, may be difficult to diagnose, causing frustration for ...

  9. Soil-atmosphere fluxes of the greenhouse gases N2O, CO2 and CH4 from a long term compost experiment in Austria.

    NASA Astrophysics Data System (ADS)

    Spann, Caroline; Spiegel, Heide; Kitzler, Barbara

    2016-04-01

    The application of composts as fertilizers is becoming increasingly important to achieve a closed-loop economy. However, greenhouse gas (GHG) emissions, especially N2O, from agricultural fields may increase as well. In this study different compost types and N amounts were investigated, especially in terms of their GHG fluxes. We used the closed chamber method to estimate GHG flux rates over one vegetation period from an agricultural soil fertilized with different compost types. The study was conducted on a long term compost experiment site near Linz (Austria) with a crop rotation. The soil is a loamy silt and in 2015 maize was planted. Six different compost treatments were investigated. Organic waste compost (OWC) and farmyard manure compost (FMC) was applied with nitrogen concentrations of 175 (OWC1, FYC1) and 525 kg N ha-1 (OWC3, FYC3). Two compost treatments were fertilized additionally with 80 kg N ha.1 mineral fertilizer (OWC2, FYC2). One treatment (TN) was fertilized only with mineral fertilizer (120 kg N ha-1) and one treatment was not fertilized at all (C). Additionally to the GHG flux rates, ammonium and nitrate content, microbial biomass C and N and different enzyme activities were analysed in the top soil. Nitrous oxide (N2O) was emitted over the entire vegetation period with highest fluxes from April until June, until the plants have been established sufficiently. Overall, at the FMC treatments (FYC2, FYC3) highest fluxes were measured. Compared to FMC, lower N2O emissions were measured from the OWC treatments. The combination of compost and mineral N fertilization resulted in the highest N2O emissions, especially after precipitation events. The treatments OWC1 and FYC1 were not different from the control. Methane (CH4) was mainly taken up at all treatments, but uptake rates were lower at the high N input sites (OWC3, FYC3) with no differences between the compost types. No significant differences were found in the soil respiration rates.

  10. Response of lake chemistry to changes in atmospheric deposition and climate in three high-elevation wilderness areas of Colorado

    USGS Publications Warehouse

    Mast, M.A.; Turk, J.T.; Clow, D.W.; Campbell, D.H.

    2011-01-01

    Trends in precipitation chemistry and hydrologic and climatic data were examined as drivers of long-term changes in the chemical composition of high-elevation lakes in three wilderness areas in Colorado during 1985-2008. Sulfate concentrations in precipitation decreased at a rate of -0.15 to -0.55 ??eq/l/year at 10 high-elevation National Atmospheric Deposition Program stations in the state during 1987-2008 reflecting regional reductions in SO2 emissions. In lakes where sulfate is primarily derived from atmospheric inputs, sulfate concentrations also decreased although the rates generally were less, ranging from -0.12 to -0.27 ??eq/l/year. The similarity in timing and sulfur isotopic data support the hypothesis that decreases in atmospheric deposition are driving the response of high-elevation lakes in some areas of the state. By contrast, in lakes where sulfate is derived primarily from watershed weathering sources, sulfate concentrations showed sharp increases during 1985-2008. Analysis of long-term climate records indicates that annual air temperatures have increased between 0.45 and 0.93??C per decade throughout most mountainous areas of Colorado, suggesting climate as a factor. Isotopic data reveal that sulfate in these lakes is largely derived from pyrite, which may indicate climate warming is preferentially affecting the rate of pyrite weathering. ?? 2010 US Government.

  11. Response of lake chemistry to changes in atmospheric deposition and climate in three high-elevation wilderness areas of Colorado

    USGS Publications Warehouse

    Mast, M. Alisa; Turk, John T.; Clow, David W.; Campbell, Donald D.

    2011-01-01

    Trends in precipitation chemistry and hydrologic and climatic data were examined as drivers of long-term changes in the chemical composition of high-elevation lakes in three wilderness areas in Colorado during 1985-2008. Sulfate concentrations in precipitation decreased at a rate of -0.15 to -0.55 μeq/l/year at 10 high-elevation National Atmospheric Deposition Program stations in the state during 1987-2008 reflecting regional reductions in SO2 emissions. In lakes where sulfate is primarily derived from atmospheric inputs, sulfate concentrations also decreased although the rates generally were less, ranging from -0.12 to -0.27 μeq/l/year. The similarity in timing and sulfur isotopic data support the hypothesis that decreases in atmospheric deposition are driving the response of high-elevation lakes in some areas of the state. By contrast, in lakes where sulfate is derived primarily from watershed weathering sources, sulfate concentrations showed sharp increases during 1985-2008. Analysis of long-term climate records indicates that annual air temperatures have increased between 0.45 and 0.93°C per decade throughout most mountainous areas of Colorado, suggesting climate as a factor. Isotopic data reveal that sulfate in these lakes is largely derived from pyrite, which may indicate climate warming is preferentially affecting the rate of pyrite weathering.

  12. Fully coupled atmospheric-hydrological modeling at regional and long-term scales: Development, application, and analysis of WRF-HMS

    NASA Astrophysics Data System (ADS)

    Wagner, Sven; Fersch, Benjamin; Yuan, Fei; Yu, Zhongbo; Kunstmann, Harald

    2016-04-01

    A closed description of the regional water balance requires hydro-meteorological modeling systems which represent the atmosphere, land surface, and subsurface. We developed such a mesoscale modeling system, extending the atmospheric model WRF with the distributed hydrological model HMS in a fully coupled way. It includes explicit lateral groundwater and land surface flow parameterization schemes and two-way groundwater-unsaturated zone interaction by replacing the free drainage bottom boundary of WRF's Noah-LSM with a Fixed-head or Darcy-flux boundary condition. The system is exemplarily applied for the Poyang Lake basin (160,000 km2) and the period 1979-1986 using a two-nest approach covering East Asia (30 km) and the Poyang Lake basin (10 km) driven by ERA Interim. Stand-alone WRF effectively simulates temperature (bias 0.5°C) and precipitation (bias 21-26%). Stand-alone HMS simulations provide reasonable streamflow estimates. A significant impact on the regional water balance was found if groundwater-unsaturated zone interaction is considered. But the differences between the two groundwater coupling approaches are minor. For the fully coupled model system, streamflow results strongly depend on the simulation quality for precipitation. Two-way interaction results in net upward water fluxes in up to 25% of the basin area after the rainy season. In total, two-way interaction increases basin averaged recharge amounts. The evaluation with CPC and GLEAM indicates a better performance of the fully coupled simulation. The impact of groundwater coupling on LSM and atmospheric variables differs. Largest differences occur for the variable recharge (26%), whereas for atmospheric variables, the basin-averaged impact is minor (<1%). But locally, a spatial redistribution up to ±5% occurs for precipitation.

  13. Rule-based expert system for evaluating the quality of long-term, in-situ, gas chromatographic measurements of atmospheric methane. Technical memo

    SciTech Connect

    Masarie, K.A.; Steele, L.P.; Lang, P.M.

    1991-11-01

    Methane is an important trace constituent of the earth's atmosphere because it is active both chemically and radiatively. The absorption of infrared radiation by atmospheric methane, and the rapid increase in the global atmospheric burden of methane over the past century combine to raise concerns that continued increases may contribute to global warming and climate change within the next century. The use of a rule-based expert system to assess the integrity of in situ gas chromatographic methane measurements made at the NOAA/CMDL Point Barrow, Alaska and Mauna Loa, Hawaii observatories is presented. The expert system flags ambient samples analyzed during chromatograph system instability and excludes them from further scientific analysis. The development and implementation of the expert system are described in detail. A comparison between data sets flagged by a human expert and by the expert system shows that the expert system can successfully reproduce the efforts of a human when evaluating gas chromatograph system stability. Advantages and limitations of the use of an expert system for the task are also discussed.

  14. Long-term atmospheric wet deposition of dissolved organic nitrogen in a typical red-soil agro-ecosystem, Southeastern China.

    PubMed

    Cui, Jian; Zhou, Jing; Peng, Ying; He, Yuan Q; Yang, Hao; Xu, Liang J; Chan, Andy

    2014-05-01

    Dissolved organic nitrogen (DON) from atmospheric deposition has been a growing concern in the world and atmospheric nitrogen (N) deposition is increasing quickly in China especially Southeastern China. In our study, DON wet deposition was estimated by collecting and analyzing rainwater samples continuously over eight years (2005-2012) in a typical red-soil farmland ecosystem, Southeast China. Results showed that the volume-weighted-average DON concentration varied from 0.2 to 3.3 mg N L(-1) with an average of 1.2 mg N L(-1). DON flux ranged from 5.7 to 71.6 kg N ha(-1) year(-1) and averaged 19.7 kg N ha(-1) year(-1) which accounted for 34.6% of the total dissolved nitrogen (TDN) in wet deposition during the eight-year period. Analysis of DON concentration and flux, contribution of DON to TDN, rainfall, rain frequency, air temperature and wind frequency and the application of pig manure revealed possible pollution sources. Significant positive linear relation of annual DON flux and usage of pig manure (P<0.0001) suggested that agricultural activities, especially application of pig manure, were the main source of DON in the study area. In conclusion, DON wet deposition was an important part of TDN and would have a possible effect on N cycle in the red-soil agro-ecosystem in the future. PMID:24643306

  15. Effects of dynamic controlled atmosphere by respiratory quotient on some quality parameters and volatile profile of 'Royal Gala' apple after long-term storage.

    PubMed

    Both, Vanderlei; Thewes, Fabio Rodrigo; Brackmann, Auri; de Oliveira Anese, Rogerio; de Freitas Ferreira, Daniele; Wagner, Roger

    2017-01-15

    The effects of dynamic controlled atmosphere (DCA) storage based on chlorophyll fluorescence (DCA-CF) and respiratory quotient (DCA-RQ) on the quality and volatile profile of 'Royal Gala' apple were evaluated. DCA storage reduces ACC (1-aminocyclopropane-1-carboxylate) oxidase activity, ethylene production and respiration rate of apples stored for 9months at 1.0°C plus 7days at 20°C, resulting in higher flesh firmness, titratable acidity and lesser physiological disorders, and provided a higher proportion of healthy fruit. Storage in a regular controlled atmosphere gave higher levels of key volatiles (butyl acetate, 2-methylbutyl acetate and hexyl acetate), as compared to fruit stored under DCA-CF, but fruit stored under DCA-RQ 1.5 and RQ 2.0 also showed higher amounts of key volatile compounds, with increment in ethanol and ethyl acetate, but far below the odour threshold. Storage in DCA-CF reduces fruit ester production, especially 2-methylbutyl acetate, which is the most important component of 'Royal Gala' apple flavour. PMID:27542502

  16. Using environmental and growth characteristics of plants to detect long-term changes in response to atmospheric pollution: some examples from British beechwoods.

    PubMed

    Ling, K A

    2003-07-01

    This study uses the Ellenberg system of plant indicator values, along with Grime et al.'s plant growth strategy values, to investigate the nature of temporal changes in the composition of ground flora in two beechwoods in the Cotswolds region of the UK, currently receiving atmospheric inputs of nitrogen in excess of critical loads. The woods, first surveyed in the early 1960s, were resurveyed in 1998 using the original sampling protocol. Temporal changes in the abundance of individual species at Blackstable West Wood indicate changes in light over time, although decreases in sun species, and both increases and decreases in shade species suggest that this change has been patchy. Analysis of changes in plant community as represented by weighted and unweighted quadrat Ellenberg and CSR scores have yielded more significant results. Blackstable West Wood shows increases in nitrophilic, moist-soil and competitive species accompanied by a decline in stress-tolerant species. In Buckholt Top Wood there has been an increase in sun and moist-soil species, a decrease in competitive species and, when weighted Ellenberg scores are considered, an increase in acid-tolerant species. These changes indicate both the impact of woodland management by selective felling and an underlying influence of enhanced atmospheric deposition especially of nitrogen pollutants. It is concluded that quadrat mean scores are a useful tool especially where few individual species have undergone large temporal changes in abundance. However, lack of correlations between quadrat Ellenberg scores for pH and light on one hand, and their equivalents measured in the field, i.e. soil pH and surrogates for light, such as distance to the nearest tree and tree density, suggest that this approach may not be sensitive enough to pick up small-scale, within site variations. Although harder to interpret, plant strategy scores were found to be a useful additional descriptor, encapsulating a plant's response to a range of

  17. Estimation of long-term density variations in the upper atmosphere of the earth at minimums of solar activity from evolution of the orbital parameters of the earth's artificial satellites

    NASA Astrophysics Data System (ADS)

    Volkov, I. I.; Suevalov, V. V.

    2005-03-01

    Long-term data on the evolution of the parameters of motion of 15 artificial satellites of the Earth in orbits with minimal heights of 400 1100 km were used to study the density variations in the upper atmosphere at minimums of four cycles of solar activity. It was found that the density at these heights considered increased by about 7% at the minimum of solar cycle 20 as compared to solar cycle 19. Later, the density fell rather linearly at the minimums of cycles 21 and 22. The statistical processing of the data for solar cycles 20 22 demonstrated that the density decreased by 4.6% over ten years and by 9.9% over 20 years. Analyzing the density variations during the four cycles of solar activity, we found that the long-term decrease in density observed at the minimums of cycles 20 22 is caused mainly by specific variations of the solar activity parameters (namely, the solar radio flux and the level of geomagnetic disturbance).

  18. A two-dimensional ocean model for long-term climatic simulations: Stability and coupling to atmospheric and sea ice models

    NASA Astrophysics Data System (ADS)

    Harvey, L. D. Danny

    1992-06-01

    and the horizontal diffusion coefficient in the mixed layer are not too large. Globally averaged atmospheric temperature changes of 2 K are driven by oscillations in the heat flux into or out of the deep ocean, with the sudden onset of a heat flux out of the deep ocean associated with the rapid onset of thermohaline overturning after a quiescent period, and the sudden onset of a heat flux into the deep ocean associated with the collapse of thermohaline overturning. When the coupled model is run with prescribed parameters (such as land-sea fraction and precipitation) varying with latitude based on observations, the model does not oscillate and produces a reasonable deep ocean temperature field but a completely unrealistic salinity field. Resetting the mixed layer salinity to observations on each time step (equivalent to the "flux correction" method used in atmosphere-ocean general circulation models) is sufficient to give a realistic salinity field throughout the ocean depth, but dramatically alters the flow field and associated heat transport. Although the model is highly idealized, the finding that the maximum perturbation in globally averaged heat flux from the deep ocean to the surface over a 100-year period is 1.4 W m-2 suggests that effect of continuing greenhouse gas increases, which could result in a heating perturbation of 10 W m-2 by the end of the next century, will swamp possible surface heating perturbations due to changes in oceanic circulation. On the other hand, the extreme sensitivity of the oceanic flow field to variations in precipitation and evaporation suggests that it will not be possible to produce accurate projections of regional climatic change in the near term, if at all.

  19. Extreme events in total ozone over Arosa - Part 2: Fingerprints of atmospheric dynamics and chemistry and effects on mean values and long-term changes

    NASA Astrophysics Data System (ADS)

    Rieder, H. E.; Staehelin, J.; Maeder, J. A.; Peter, T.; Ribatet, M.; Davison, A. C.; Stübi, R.; Weihs, P.; Holawe, F.

    2010-10-01

    In this study the frequency of days with extreme low (termed ELOs) and extreme high (termed EHOs) total ozone values and their influence on mean values and trends are analyzed for the world's longest total ozone record (Arosa, Switzerland). The results show (i) an increase in ELOs and (ii) a decrease in EHOs during the last decades and (iii) that the overall trend during the 1970s and 1980s in total ozone is strongly dominated by changes in these extreme events. After removing the extremes, the time series shows a strongly reduced trend (reduction by a factor of 2.5 for trend in annual mean). Excursions in the frequency of extreme events reveal "fingerprints" of dynamical factors such as ENSO or NAO, and chemical factors, such as cold Arctic vortex ozone losses, as well as major volcanic eruptions of the 20th century (Gunung Agung, El Chichón, Mt. Pinatubo). Furthermore, atmospheric loading of ozone depleting substances leads to a continuous modification of column ozone in the Northern Hemisphere also with respect to extreme values (partly again in connection with polar vortex contributions). Application of extreme value theory allows the identification of many more such "fingerprints" than conventional time series analysis of annual and seasonal mean values. The analysis shows in particular the strong influence of dynamics, revealing that even moderate ENSO and NAO events have a discernible effect on total ozone. Overall the approach to extremal modelling provides new information on time series properties, variability, trends and the influence of dynamics and chemistry, complementing earlier analyses focusing only on monthly (or annual) mean values.

  20. Extreme events in total ozone over Arosa - Part 2: Fingerprints of atmospheric dynamics and chemistry and effects on mean values and long-term changes

    NASA Astrophysics Data System (ADS)

    Rieder, H. E.; Staehelin, J.; Maeder, J. A.; Peter, T.; Ribatet, M.; Davison, A. C.; Stübi, R.; Weihs, P.; Holawe, F.

    2010-05-01

    In this study the frequency of days with extreme low (termed ELOs) and extreme high (termed EHOs) total ozone values and their influence on mean values and trends are analyzed for the world's longest total ozone record (Arosa, Switzerland). The results show (a) an increase in ELOs and (b) a decrease in EHOs during the last decades and (c) that the overall trend during the 1970s and 1980s in total ozone is strongly dominated by changes in these extreme events. After removing the extremes, the time series shows a strongly reduced trend (reduction by a factor of 2.5 for trend in annual mean). Excursions in the frequency of extreme events reveal "fingerprints" of dynamical factors such as ENSO or NAO, and chemical factors, such as cold Arctic vortex ozone losses, as well as major volcanic eruptions of the 20th century (Gunung Agung, El Chichón, Mt. Pinatubo). Furthermore, atmospheric loading of ozone depleting substances leads to a continuous modification of column ozone in the Northern Hemisphere also with respect to extreme values (partly again in connection with polar vortex contributions). Application of extreme value theory allows the identification of many more such "fingerprints" than conventional time series analysis of annual and seasonal mean values. The analysis shows in particular the strong influence of dynamics, revealing that even moderate ENSO and NAO events have a discernible effect on total ozone. Overall the approach to extremal modelling provides new information on time series properties, variability, trends and the influence of dynamics and chemistry, complementing earlier analyses focusing only on monthly (or annual) mean values.

  1. Long Term Illness and Wages

    ERIC Educational Resources Information Center

    Sandy, Robert; Elliott, Robert R.

    2005-01-01

    Long-term illness (LTI) is a more prevalent workplace risk than fatal accidents but there is virtually no evidence for compensating differentials for a broad measure of LTI. In 1990 almost 3.4 percent of the U.K. adult population suffered from a LTI caused solely by their working conditions. This paper provides the first estimates of compensating…

  2. Long-term data archiving

    SciTech Connect

    Moore, David Steven

    2009-01-01

    Long term data archiving has much value for chemists, not only to retain access to research and product development records, but also to enable new developments and new discoveries. There are some recent regulatory requirements (e.g., FDA 21 CFR Part 11), but good science and good business both benefit regardless. A particular example of the benefits of and need for long term data archiving is the management of data from spectroscopic laboratory instruments. The sheer amount of spectroscopic data is increasing at a scary rate, and the pressures to archive come from the expense to create the data (or recreate it if it is lost) as well as its high information content. The goal of long-term data archiving is to save and organize instrument data files as well as any needed meta data (such as sample ID, LIMS information, operator, date, time, instrument conditions, sample type, excitation details, environmental parameters, etc.). This editorial explores the issues involved in long-term data archiving using the example of Raman spectral databases. There are at present several such databases, including common data format libraries and proprietary libraries. However, such databases and libraries should ultimately satisfy stringent criteria for long term data archiving, including readability for long times into the future, robustness to changes in computer hardware and operating systems, and use of public domain data formats. The latter criterion implies the data format should be platform independent and the tools to create the data format should be easily and publicly obtainable or developable. Several examples of attempts at spectral libraries exist, such as the ASTM ANDI format, and the JCAMP-DX format. On the other hand, proprietary library spectra can be exchanged and manipulated using proprietary tools. As the above examples have deficiencies according to the three long term data archiving criteria, Extensible Markup Language (XML; a product of the World Wide Web

  3. Digital elevation model visibility including Earth's curvature and atmosphere refraction

    NASA Astrophysics Data System (ADS)

    Santossilva, Ewerton; Vieiradias, Luiz Alberto

    1990-03-01

    There are some instances in which the Earth's curvature and the atmospheric refraction, optical or electronic, are important factors when digital elevation models are used for visibility calculations. This work deals with this subject, suggesting a practical approach to solve this problem. Some examples, from real terrain data, are presented. The equipment used was an IBM-PC like computer with a SITIM graphic card.

  4. Modeling low elevation GPS signal propagation in maritime atmospheric ducts

    NASA Astrophysics Data System (ADS)

    Zhang, Jinpeng; Wu, Zhensen; Wang, Bo; Wang, Hongguang; Zhu, Qinglin

    2012-05-01

    Using the parabolic wave equation (PWE) method, we model low elevation GPS L1 signal propagation in maritime atmospheric ducts. To consider sea surface impedance, roughness, and the effects of earth's curvature, we propose a new initial field model for the GPS PWE split-step solution. On the basis of the comparison between the proposed model and the conventional initial field model for a smooth, perfectly conducting sea surface on a planar earth, we conclude that both the amplitude and phase of the initial field are influenced by surface impedance and roughness, and that the interference behavior between direct and reflected GPS rays is affected by earth's curvature. The performance of the proposed model is illustrated with examples of low elevation GPS L1 signal propagation in three types of ducts: an evaporation duct, a surface-based duct, and an elevated duct. The GPS PWE is numerically implemented using the split-step discrete mixed Fourier transform algorithm to enforce impedance-type boundary conditions at the rough sea surface. Because the GPS signal is right hand circularly polarized, we calculate its power strength by combining the propagation predictions of the horizontally and the vertically polarized components. The effects of the maritime atmospheric ducts on low elevation GPS signal propagation are demonstrated according to the presented examples, and the potential applications of the GPS signals affected by ducts are discussed.

  5. Long-Term Solar Irradiance Variability

    NASA Technical Reports Server (NTRS)

    Pap, J. M.

    1996-01-01

    Measurements of the solar energy throughout the solar spectrum and understanding its variability provide important information about the physical processes and structural changes in the solar interior and in the solar atmosphere...The aim of this paper is to discuss the solar-cycle-related long-term changes in solar total and UV irradiances. The spaceborne irradiance observations are compared to ground-based indices of solar magnetic activity, such as the Photometric Sunspot Index, full disk magnetic flux, and the Mt. Wilson Magnetic Plage Strength Index.

  6. Responses of soil cellulolytic fungal communities to elevated atmospheric CO₂ are complex and variable across five ecosystems.

    PubMed

    Weber, Carolyn F; Zak, Donald R; Hungate, Bruce A; Jackson, Robert B; Vilgalys, Rytas; Evans, R David; Schadt, Christopher W; Megonigal, J Patrick; Kuske, Cheryl R

    2011-10-01

    Elevated atmospheric CO(2) generally increases plant productivity and subsequently increases the availability of cellulose in soil to microbial decomposers. As key cellulose degraders, soil fungi are likely to be one of the most impacted and responsive microbial groups to elevated atmospheric CO(2). To investigate the impacts of ecosystem type and elevated atmospheric CO(2) on cellulolytic fungal communities, we sequenced 10,677 cbhI gene fragments encoding the catalytic subunit of cellobiohydrolase I, across five distinct terrestrial ecosystem experiments after a decade of exposure to elevated CO(2). The cbhI composition of each ecosystem was distinct, as supported by weighted Unifrac analyses (all P-values; < 0.001), with few operational taxonomic units (OTUs) being shared across ecosystems. Using a 114-member cbhI sequence database compiled from known fungi, less than 1% of the environmental sequences could be classified at the family level indicating that cellulolytic fungi in situ are likely dominated by novel fungi or known fungi that are not yet recognized as cellulose degraders. Shifts in fungal cbhI composition and richness that were correlated with elevated CO(2) exposure varied across the ecosystems. In aspen plantation and desert creosote bush soils, cbhI gene richness was significantly higher after exposure to elevated CO(2) (550 µmol mol(-1)) than under ambient CO(2) (360 µmol mol(-1) CO(2)). In contrast, while the richness was not altered, the relative abundance of dominant OTUs in desert soil crusts was significantly shifted. This suggests that responses are complex, vary across different ecosystems and, in at least one case, are OTU-specific. Collectively, our results document the complexity of cellulolytic fungal communities in multiple terrestrial ecosystems and the variability of their responses to long-term exposure to elevated atmospheric CO(2). PMID:21883796

  7. Responses of soil cellulolytic fungal communities to elevated atmospheric CO2 are complex and variableacross five ecosystems

    SciTech Connect

    Weber, Carolyn F; Zak, Donald R; Hungate, Bruce; Jackson, Robert B; Vilgalys, Rytas; Evans, R David; Schadt, Christopher Warren; Megonigal, J. Patrick; Kuske, Cheryl R

    2011-01-01

    Elevated atmospheric CO(2) generally increases plant productivity and subsequently increases the availability of cellulose in soil to microbial decomposers. As key cellulose degraders, soil fungi are likely to be one of the most impacted and responsive microbial groups to elevated atmospheric CO(2) . To investigate the impacts of ecosystem type and elevated atmospheric CO(2) on cellulolytic fungal communities, we sequenced 10 677 cbhI gene fragments encoding the catalytic subunit of cellobiohydrolase I, across five distinct terrestrial ecosystem experiments after a decade of exposure to elevated CO(2) . The cbhI composition of each ecosystem was distinct, as supported by weighted Unifrac analyses (all P-values; < 0.001), with few operational taxonomic units (OTUs) being shared across ecosystems. Using a 114-member cbhI sequence database compiled from known fungi, less than 1% of the environmental sequences could be classified at the family level indicating that cellulolytic fungi in situ are likely dominated by novel fungi or known fungi that are not yet recognized as cellulose degraders. Shifts in fungal cbhI composition and richness that were correlated with elevated CO(2) exposure varied across the ecosystems. In aspen plantation and desert creosote bush soils, cbhI gene richness was significantly higher after exposure to elevated CO(2) (550 mol mol(-1) ) than under ambient CO(2) (360 mol mol(-1) CO(2) ). In contrast, while the richness was not altered, the relative abundance of dominant OTUs in desert soil crusts was significantly shifted. This suggests that responses are complex, vary across different ecosystems and, in at least one case, are OTU-specific. Collectively, our results document the complexity of cellulolytic fungal communities in multiple terrestrial ecosystems and the variability of their responses to long-term exposure to elevated atmospheric CO(2) .

  8. Development of a real time monitor and multivariate method for long term diagnostics of atmospheric pressure dielectric barrier discharges: application to He, He/N2, and He/O2 discharges.

    PubMed

    O'Connor, N; Milosavljević, V; Daniels, S

    2011-08-01

    In this paper we present the development and application of a real time atmospheric pressure discharge monitoring diagnostic. The software based diagnostic is designed to extract latent electrical and optical information associated with the operation of an atmospheric pressure dielectric barrier discharge (APDBD) over long time scales. Given that little is known about long term temporal effects in such discharges, the diagnostic methodology is applied to the monitoring of an APDBD in helium and helium with both 0.1% nitrogen and 0.1% oxygen gas admixtures over periods of tens of minutes. Given the large datasets associated with the experiments, it is shown that this process is much expedited through the novel application of multivariate correlations between the electrical and optical parameters of the corresponding chemistries which, in turn, facilitates comparisons between each individual chemistry also. The results of these studies show that the electrical and optical parameters of the discharge in helium and upon the addition of gas admixtures evolve over time scales far longer than the gas residence time and have been compared to current modelling works. It is envisaged that the diagnostic together with the application of multivariate correlations will be applied to rapid system identification and prototyping in both experimental and industrial APDBD systems in the future. PMID:21895242

  9. Long-term variation of energetic electron precipitation

    NASA Astrophysics Data System (ADS)

    Asikainen, Timo

    2015-04-01

    The long-term evolution of energetic electron precipitation (EEP) is of considerable interest, e.g., because of its atmospheric and climatic effects. However, the long-term evolution of EEP over several solar cycles has been problematic due to the lack of reliable long-term data. The NOAA/POES satellites have measured energetic particles for more than 35 years. This dataset has been used widely but it has been plagued by several instrumental problems, which have restricted its use for long-term studies. However, we have recently corrected and recalibrated the entire NOAA/POES energetic particle dataset. Using this unique dataset we present here an overview of the long-term evolution of EEP paying particular attention to the role of different types of solar wind disturbances in driving the EEP.

  10. Tracing changes of N2O emission pathways in a permanent grassland under elevated atmospheric CO2 concentrations

    NASA Astrophysics Data System (ADS)

    Gorenflo, Andre; Moser, Gerald; Brenzinger, Kristof; Elias, Dafydd; McNamara, Neill; Clough, Tim; Maček, Irena; Vodnik, Dominik; Braker, Gesche; Schimmelpfennig, Sonja; Gerstner, Judith; Müller, Christoph

    2015-04-01

    The increase of greenhouse gases (GHG) in the atmosphere is of concern due to its effect on global temperatures. Nitrous oxide (N2O) with a Global Warming Potential of 298 over a 100 year period is of particular concern because strong feedback effects of elevated atmospheric CO2 on N2O emissions have been observed. However, so far the changes in processes which are responsible for such a feedback effect are only poorly understood. Our study was carried out in situ in a long-term Free Air Carbon dioxide Enrichment (FACE) study on permanent grassland at atmospheric CO2 concentrations 20% above ambient which expected at the middle of this century. We performed an in situ 15N tracing with differentially labelled NH4NO3 to trace the main N2O emission pathways. Over a period of more than one year we monitored at least weakly the N2O emissions with the closed chamber technique and analyzed the 15N signature of the N2O. The observed gaseous emissions under ambient and elevated atmospheric CO2 were associated with the observed gross N transformations and the microbial activities to identify the main emission pathways under ambient and elevated CO2.

  11. Elevated atmospheric CO2 increases microbial growth rates and enzymes activity in soil

    NASA Astrophysics Data System (ADS)

    Blagodatskaya, Evgenia; Blagodatsky, Sergey; Dorodnikov, Maxim; Kuzyakov, Yakov

    2010-05-01

    Increasing the belowground translocation of assimilated carbon by plants grown under elevated CO2 can cause a shift in the structure and activity of the microbial community responsible for the turnover of organic matter in soil. We investigated the long-term effect of elevated CO2 in the atmosphere on microbial biomass and specific growth rates in root-free and rhizosphere soil. The experiments were conducted under two free air carbon dioxide enrichment (FACE) systems: in Hohenheim and Braunschweig, as well as in the intensively managed forest mesocosm of the Biosphere 2 Laboratory (B2L) in Oracle, AZ. Specific microbial growth rates (μ) were determined using the substrate-induced respiration response after glucose and/or yeast extract addition to the soil. We evaluated the effect of elevated CO2 on b-glucosidase, chitinase, phosphatase, and sulfatase to estimate the potential enzyme activity after soil amendment with glucose and nutrients. For B2L and both FACE systems, up to 58% higher μ were observed under elevated vs. ambient CO2, depending on site, plant species and N fertilization. The μ-values increased linearly with atmospheric CO2 concentration at all three sites. The effect of elevated CO2 on rhizosphere microorganisms was plant dependent and increased for: Brassica napus=Triticum aestivumelevated CO2 was smoothed on rich vs. simple substrate. So, the r/K strategies ratio can be better revealed by studying growth on simple (glucose) than on rich substrate mixtures (yeast extract). After adding glucose, enzyme activities under elevated CO2 were

  12. Stapedectomy - long-term report.

    PubMed

    Shea, J J

    1982-01-01

    The long-term results with large fenestra stapedectomy with vein graft and Teflon piston are compared with results with the small fenestra stapedectomy with teflon piston directly into the vestibule. There were 1,943 operations in the former group and 2,155 in the latter when compared in 1970. One hundred consecutive patients from the beginning of each group with follow-up to present were compared. Results were generally the same with no great change in 15 and 20 years as compared to those at 5 years. The complication of perilymph fistula was caused by creating an opening in the footplate much larger than the prosthesis and was eliminated by interposing a living oval window seal if the opening was much larger than the prosthesis and a flap of lining membrane from the promontory when it was not. Other factors that influence a good result are discussed, including the type and the diameter of the piston used, the type of living oval window seal and the method of attachment to the incus. The small fenestra operation was found to be superior to the large, not only for the hearing gain achieved, but the case of performance and the freedom from complications due to migration of the prosthesis and/or the oval window seal. At present we have done about all that can be done for the conductive components. What remains is the sensorineural component which our studies indicate may be due to an autoimmune response. PMID:6897157

  13. Long Term Surface Salinity Measurements

    NASA Technical Reports Server (NTRS)

    Schmitt, Raymond W.; Brown, Neil L.

    2005-01-01

    Our long-term goal is to establish a reliable system for monitoring surface salinity around the global ocean. Salinity is a strong indicator of the freshwater cycle and has a great influence on upper ocean stratification. Global salinity measurements have potential to improve climate forecasts if an observation system can be developed. This project is developing a new internal field conductivity cell that can be protected from biological fouling for two years. Combined with a temperature sensor, this foul-proof cell can be deployed widely on surface drifters. A reliable in-situ network of surface salinity sensors will be an important adjunct to the salinity sensing satellite AQUARIUS to be deployed by NASA in 2009. A new internal-field conductivity cell has been developed by N Brown, along with new electronics. This sensor system has been combined with a temperature sensor to make a conductivity - temperature (UT) sensor suitable for deployment on drifters. The basic sensor concepts have been proven on a high resolution CTD. A simpler (lower cost) circuit has been built for this application. A protection mechanism for the conductivity cell that includes antifouling protection has also been designed and built. Mr. A.Walsh of our commercial partner E-Paint has designed and delivered time-release formulations of antifoulants for our application. Mr. G. Williams of partner Clearwater Instrumentation advised on power and communication issues and supplied surface drifters for testing.

  14. Elevated atmospheric carbon dioxide in agroecosystems affects groundwater quality

    SciTech Connect

    Torbert, H.A.; Prior, S.A.; Rogers, H.H.; Schlesinger, W.H.; Mullins, G.L.; Runion, G.B.

    1996-07-01

    Increasing atmospheric carbon dioxide (CO{sub 2}) concentration has led to concerns about global changes to the environment. One area of global change that has not been addressed is the effect of elevated atmospheric CO{sub 2} on groundwater quality below agroecosystems. Elevated CO{sub 2} concentration alterations of plant growth and C/N ratios may modify C and N cycling in soil and affect nitrate (NO{sub 3}{sup {minus}}) leaching to groundwater. This study was conducted to examine the effects of a legume (soybean [Glycine max (L.) Merr.]) and a nonlegume (grain sorghum [Sorghum bicolor (L.) Moench]) CO{sub 2}-enriched agroecosystems on NO{sub 3}{sup {minus}} movement below the root zone in a Blanton loamy sand (loamy siliceous, thermic, Grossarenic Paleudults). The study was a split-plot design replicated three times with plant species (soybean and grain sorghum) as the main plots and CO{sub 2} concentration ({approximately}360 and {approximately}720 {mu}L L{sup {minus}1} CO{sub 2}) as subplots using open-top field chambers. Fertilizer application was made with {sup 15}N-depleted NH{sub 4}NO{sub 3} to act as a fertilizer tracer. Soil solution samples were collected weekly at 90-cm depth for a 2-yr period and monitored for NO{sub 3}{sup {minus}}-N concentrations. Isotope analysis of soil solution indicated that the decomposition of organic matter was the primary source of No{sub 3}{sup {minus}}-N in soil solution below the root zone through most of the monitoring period. Significant differences were observed for NO{sub 3}{sup {minus}}-N concentrations between soybean and grain sorghum, with soybean having the higher NO{sub 3}{sup {minus}}-N concentration. Elevated CO{sub 2} increased total dry weight, total N content, and C/N ratio of residue returned to soil in both years. Elevated CO{sub 2} significantly decreased NO{sub 3}{sup {minus}}-N concentrations below the root zone in both soybean and grain sorghum. 37 refs., 2 figs., 2 tabs.

  15. GRACE Score among Six Risk Scoring Systems (CADILLAC, PAMI, TIMI, Dynamic TIMI, Zwolle) Demonstrated the Best Predictive Value for Prediction of Long-Term Mortality in Patients with ST-Elevation Myocardial Infarction

    PubMed Central

    Littnerova, Simona; Kala, Petr; Jarkovsky, Jiri; Kubkova, Lenka; Prymusova, Krystyna; Kubena, Petr; Tesak, Martin; Toman, Ondrej; Poloczek, Martin; Spinar, Jindrich; Dusek, Ladislav; Parenica, Jiri

    2015-01-01

    Aim To compare the prognostic accuracy of six scoring models for up to three-year mortality and rates of hospitalisation due to acute decompensated heart failure (ADHF) in STEMI patients. Methods and Results A total of 593 patients treated with primary PCI were evaluated. Prospective follow-up of patients was ≥3 years. Thirty-day, one-year, two-year, and three-year mortality rates were 4.0%, 7.3%, 8.9%, and 10.6%, respectively. Six risk scores—the TIMI score and derived dynamic TIMI, CADILLAC, PAMI, Zwolle, and GRACE—showed a high predictive accuracy for six- and 12-month mortality with area under the receiver operating characteristic curve (AUC) values of 0.73–0.85. The best predictive values for long-term mortality were obtained by GRACE. The next best-performing scores were CADILLAC, Zwolle, and Dynamic TIMI. All risk scores had a lower prediction accuracy for repeat hospitalisation due to ADHF, except Zwolle with the discriminatory capacity for hospitalisation up to two years (AUC, 0.80–0.83). Conclusions All tested models showed a high predictive value for the estimation of one-year mortality, but GRACE appears to be the most suitable for the prediction for a longer follow-up period. The tested models exhibited an ability to predict the risk of ADHF, especially the Zwolle model. PMID:25893501

  16. Long-term solar-terrestrial observations

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The results of an 18-month study of the requirements for long-term monitoring and archiving of solar-terrestrial data is presented. The value of long-term solar-terrestrial observations is discussed together with parameters, associated measurements, and observational problem areas in each of the solar-terrestrial links (the sun, the interplanetary medium, the magnetosphere, and the thermosphere-ionosphere). Some recommendations are offered for coordinated planning for long-term solar-terrestrial observations.

  17. Global, long-term surface reflectance records from Landsat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global, long-term monitoring of changes in Earth’s land surface requires quantitative comparisons of satellite images acquired under widely varying atmospheric conditions. Although physically based estimates of surface reflectance (SR) ultimately provide the most accurate representation of Earth’s s...

  18. Response of a tundra ecosystem to elevated atmospheric carbon dioxide and CO{sub 2}-induced climate change. [Annual report

    SciTech Connect

    Oechel, W.C.

    1989-12-31

    Predicting the response of northern ecosystems to increases in atmospheric CO{sub 2} and associated climatic change is important for several reasons, including the fact that northern ecosystems contain large stores of carbon, most of which is below ground and because northern ecosystems could conceivably be either sources or sinks for CO{sub 2} under future climatic and atmospheric CO{sub 2} concentrations. The carbon in northern ecosystems is equal to about 20% of the world`s terrestrial carbon and about 70% of the carbon currently in the atmosphere. Eighty-three percent of this carbon is below ground in the seasonally-thawed upper soil layers and in the permanently frozen zone, the permafrost. Because of bogs and permafrost, northern ecosystems are unusual in that they can potentially store significant amounts of carbon over long time periods. Most other mature ecosystems have little capacity for long- term carbon storage. Given the right conditions, northern ecosystems can also release a significant amount of carbon. A substantial amount of the carbon stored in northern ecosystems, and much of the future storage potential, is in the tundra regions. These systems could conceivably act as sources or sinks depending on developing climatic and atmospheric conditions. Our recent work indicates that elevated CO{sub 2} alone will have little effect on carbon storage in the tundra. However, the combination of elevated atmospheric CO{sub 2} (+ 340 ppm) and air temperature (+4{degrees}C) in the absence of any change in soil water table or soil moisture content, should result in significant increases in carbon sequestering in the tundra. However, if changing climate results in a decrease in the water table and soil moisture levels, this may lead to sizeable losses of carbon from the tundra soils.

  19. Long-term preservation of Anammox bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deposit of useful microorganisms in culture collections requires long-term preservation and successful reactivation techniques. The goal of this study was to develop a simple preservation protocol for the long-term storage and reactivation of the anammox biomass. To achieve this, anammox biomass w...

  20. Long Term Preservation of Digital Information.

    ERIC Educational Resources Information Center

    Lorie, Raymond A.

    The preservation of digital data for the long term presents a variety of challenges from technical to social and organizational. The technical challenge is to ensure that the information, generated today, can survive long term changes in storage media, devices, and data formats. This paper presents a novel approach to the problem. It distinguishes…

  1. Virtual Models of Long-Term Care

    ERIC Educational Resources Information Center

    Phenice, Lillian A.; Griffore, Robert J.

    2012-01-01

    Nursing homes, assisted living facilities and home-care organizations, use web sites to describe their services to potential consumers. This virtual ethnographic study developed models representing how potential consumers may understand this information using data from web sites of 69 long-term-care providers. The content of long-term-care web…

  2. Paying for long-term care.

    PubMed Central

    Estes, C L; Bodenheimer, T

    1994-01-01

    Everyone agrees that insurance for long-term care is inadequate in the United States. Disagreement exists, however, on whether such insurance should be provided through the private or public sector. Private insurance generally uses the experience-rating principle that persons with higher risk of illness are charged higher premiums. For private insurance for long-term care, this principle creates a dilemma. Most policies will be purchased by the elderly; yet, because the elderly have a high risk of needing long-term care, only about 20% of them can afford the cost of premiums. A public-private partnership by which the government partially subsidizes private long-term-care insurance is unlikely to resolve this dilemma. Only a social insurance program for long-term care can provide universal, affordable, and equitable coverage. PMID:8128712

  3. Long term prediction of flood occurrence

    NASA Astrophysics Data System (ADS)

    Aguilar, Cristina; Montanari, Alberto; José Polo, María

    2016-05-01

    How long a river remembers its past is still an open question. Perturbations occurring in large catchments may impact the flow regime for several weeks and months, therefore providing a physical explanation for the occasional tendency of floods to occur in clusters. The research question explored in this paper may be stated as follows: can higher than usual river discharges in the low flow season be associated to a higher probability of floods in the subsequent high flow season? The physical explanation for such association may be related to the presence of higher soil moisture storage at the beginning of the high flow season, which may induce lower infiltration rates and therefore higher river runoff. Another possible explanation is persistence of climate, due to presence of long-term properties in atmospheric circulation. We focus on the Po River at Pontelagoscuro, whose catchment area amounts to 71 000 km2. We look at the stochastic connection between average river flows in the pre-flood season and the peak flows in the flood season by using a bivariate probability distribution. We found that the shape of the flood frequency distribution is significantly impacted by the river flow regime in the low flow season. The proposed technique, which can be classified as a data assimilation approach, may allow one to reduce the uncertainty associated to the estimation of the flood probability.

  4. Current Perspectives on Long-term Obesity Pharmacotherapy.

    PubMed

    Wharton, Sean

    2016-04-01

    Approximately 1 in 4 adult Canadians are obese and, thus, are at an elevated risk for developing type 2 diabetes, cardiovascular disease and other conditions. Current treatment guidelines recommend that obese individuals lose 5% to 10% of their starting weights to minimize the risk factors for cardiovascular disease and reduce the risk for developing type 2 diabetes or hypertension. All obesity-management strategies involve lifestyle management, but few patients will lose a significant amount of weight and manage to keep it off over the long term using just this strategy. Bariatric surgery is associated with significant long-term weight loss but is restricted to subjects with very high body mass indices, who often wait many years to undergo the procedure. Recent breakthroughs in understanding the mechanisms underlying the development and maintenance of elevated body fat have led to the arrival of new obesity pharmacotherapies. These novel antiobesity therapies, which work by reducing energy intake or through increasing satiety, decreasing hunger, or reducing absorption of calories, may be used indefinitely once patients have demonstrated significant responses (usually defined as ≥5% weight loss) over the first 12 weeks of treatment. To date, 2 long-term obesity pharmacotherapies have been approved and are available in Canada: liraglutide and orlistat. Here, I summarize the mechanisms and clinical features of medications for long-term obesity management that are available in Canada, as well as those available in other jurisdictions or are currently in development. PMID:26507402

  5. Common Calibration Source for Monitoring Long-term Ozone Trends

    NASA Technical Reports Server (NTRS)

    Kowalewski, Matthew

    2004-01-01

    Accurate long-term satellite measurements are crucial for monitoring the recovery of the ozone layer. The slow pace of the recovery and limited lifetimes of satellite monitoring instruments demands that datasets from multiple observation systems be combined to provide the long-term accuracy needed. A fundamental component of accurately monitoring long-term trends is the calibration of these various instruments. NASA s Radiometric Calibration and Development Facility at the Goddard Space Flight Center has provided resources to minimize calibration biases between multiple instruments through the use of a common calibration source and standardized procedures traceable to national standards. The Facility s 50 cm barium sulfate integrating sphere has been used as a common calibration source for both US and international satellite instruments, including the Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet 2 (SBUV/2) instruments, Shuttle SBUV (SSBUV), Ozone Mapping Instrument (OMI), Global Ozone Monitoring Experiment (GOME) (ESA), Scanning Imaging SpectroMeter for Atmospheric ChartographY (SCIAMACHY) (ESA), and others. We will discuss the advantages of using a common calibration source and its effects on long-term ozone data sets. In addition, sphere calibration results from various instruments will be presented to demonstrate the accuracy of the long-term characterization of the source itself.

  6. Infarct Artery Distribution and Clinical Outcomes in Occluded Artery Trial Subjects Presenting with Non ST elevation Myocardial Infarction (From the Long Term Follow-up of the Occluded Artery Trial)

    PubMed Central

    Menon, Venu; Ruzyllo, Witold; Carvalho, Antonio C.; Marconi, Jose; de Sousa, Almeida; Forman, Sandra A.; Jaworska, Krystyna; Lamas, Gervasio A.; Roik, Marek; Thuaire, Christophe; Turgeman, Yoav; Hochman, Judith S.

    2013-01-01

    We hypothesized that the insensitivity of the electrocardiogram (ECG) in identifying acute circumflex occlusion would result in differences in the distribution of the infarct related artery (IRA) between patients with non ST elevation myocardial infarction (NSTEMI) and ST elevation myocardial infarction (STEMI) enrolled in the Occluded Artery Trial. We also sought to evaluate the impact of percutaneous intervention to the IRA on clinical outcomes for patients with NSTEMI. Overall NSTEMI subjects comprised 13% (n=283) of the trial population. The circumflex IRA was overrepresented in the NSTEMI group compared to patients enrolled with STEMI (42.5 vs. 11.2%; p<0.0001). The 7 year clinical outcomes for NSTEMI patients randomized to percutaneous intervention and optimal medical therapy versus optimal medical therapy alone were similar for the primary composite of Death, MI and Class IV Congestive Heart Failure (CHF) (22.3 vs. 20.23%, p=0.51, HR 1.20; 0.59-2.43); as well as the individual endpoints of Death (13.8 vs. 17.0%, p=0.51, HR 0.81;0.36-1.85); MI (6.1 vs. 5.1%, p=0.84, HR=1.11; 0.28-4.41); Class IV CHF (6.7 vs. 6.0%, p=0.45, HR 1.50;0.37-6.02). There was no interaction between MI type by ECG and treatment effect (p= NS). In conclusion the occluded circumflex IRA is overrepresented in the NSTEMI population. Consistent with the overall trial results, stable patients with NSTEMI and a totally occluded IRA did not benefit from randomization to PCI. PMID:23351464

  7. Robotics for Long-Term Monitoring

    SciTech Connect

    Shahin, Sarkis; Duran, Celso

    2002-07-01

    While long-term monitoring and stewardship means many things to many people, DOE has defined it as The physical controls, institutions, information, and other mechanisms needed to ensure protection of people and the environment at sites where DOE has completed or plans to complete cleanup (e.g., landfill closures, remedial actions, and facility stabilization). Across the United States, there are thousands of contaminated sites with multiple contaminants released from multiple sources where contaminants have transported and commingled. The U.S. government and U.S. industry are responsible for most of the contamination and are landowners of many of these contaminated properties. These sites must be surveyed periodically for various criteria including structural deterioration, water intrusion, integrity of storage containers, atmospheric conditions, and hazardous substance release. The surveys, however, are intrusive, time-consuming, and expensive and expose survey personnel to radioactive contamination. In long-term monitoring, there's a need for an automated system that will gather and report data from sensors without costly human labor. In most cases, a SCADA (Supervisory Control and Data Acquisition) unit is used to collect and report data from a remote location. A SCADA unit consists of an embedded computer with data acquisition capabilities. The unit can be configured with various sensors placed in different areas of the site to be monitored. A system of this type is static, i.e., the sensors, once placed, cannot be moved to other locations within the site. For those applications where the number of sampling locations would require too many sensors, or where exact location of future problems is unknown, a mobile sensing platform is an ideal solution. In many facilities that undergo regular inspections, the number of video cameras and air monitors required to eliminate the need for human inspections is very large and far too costly. HCET's remote harsh

  8. Elevated atmospheric C02 concentration and temperature across an urban-rural transect

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The heat island effect and the high use of fossil fuels in large city centers are well documented, but by how much fossil fuel consumption is elevating atmospheric CO2 concentrations and whether elevations in both atmospheric CO2 and air temperature are consistent from year to year are less well kno...

  9. Long-term ozone monitoring from space

    NASA Astrophysics Data System (ADS)

    Ahmad, S.; Johnson, J.; Serafino, G.; McPeters, R.

    Ultraviolet Spectrometer (SBUV), are archived at the Goddard DAAC and are freely available to the public. Standard products from TOMS include daily global total ozone and effective UV reflectivity of the earth-atmosphere system. Data products from future upper atmospheric research missions, e.g., the Ozone Monitoring Instrument (OMI), the Microwave Limb Sounder (MLS), and the High Resolution Dynamics Limb Sounder (HIRDLS) aboard Aura, will also be archived at the Goddard DAAC. For ozone trend analysis, a long-term data set consisting of over twenty years of ozone measurements from space and some value added research products have been produced by the NASA Goddard Space Flight Center scientists (Atmospheric Chemistry and Dynamics Branch/ Code 916) and are made available to the research community (http://code916.gsfc.nasa.gov). Examples of some of these research products are:1) daily erythermal UV exposure -estimates of harmful UV-B radiation at the surface, 2) an index to track the global transport of ash and sulfur dioxide resulting from volcanic eruptions, 3) another index to track smoke emanating from large fires and dust plumes originating from desert regions, 4) aerosol optical depth, 5) tropospheric ozone obtained from cloud-slicing techniques, and 6) a merged total ozone data product consisting of monthly mean ozone merged from six satellite instruments. The Upper Atmospheric Data Support Team has been providing science and data support to assist users in accessing and using the upper atmospheric data products. A number of tools for data access, subsetting, reprojection and mapping of orbital (Level-2) products, visualization of global gridded (Level-3) products, and data analysis have been developed at the Goddard DAAC and are freely available to the data user (http://daac.gsfc.nasa.gov) This presentation will provide highlights of the standard and value-added ozone and ancillary products, and the data services provided by the DAAC Upper Atmosphere Data Support Team.

  10. Long-term Ozone monitoring from space

    NASA Astrophysics Data System (ADS)

    Ahmad, S.; Johnson, J.; Serafino, G.; McPeters, R.

    Ultraviolet Spectrometer (SBUV), are archived at the Goddard DAAC and are freely available to the public. Standard products from TOMS include daily global total ozone and effective UV reflectivity of the earth-atmosphere system. Data products from future upper atmospheric research missions, e.g., the Ozone Monitoring Instrument (OMI), the Microwave Limb Sounder (MLS), and the High Resolution Dynamics Limb Sounder (HIRDLS) aboard Aura, will also be archived at the Goddard DAAC. For ozone trend analysis, a long-term data set consisting of over twenty years of ozone measurements from space and some value added research products have been produced by the NASA Goddard Space Flight Center scientists (Atmospheric Chemistry and Dynamics Branch/ Code 916) and are made available to the research community (http://code916.gsfc.nasa.gov). Examples of some of these research products are:1) daily erythermal UV exposure -estimates of harmful UV-B radiation at the surface, 2) an index to track the global transport of ash and sulfur dioxide resulting from volcanic eruptions, 3) another index to track smoke emanating from large fires and dust plumes originating from desert regions, 4) aerosol optical depth, 5) tropospheric ozone obtained from cloud-slicing techniques, and 6) a merged total ozone data product consisting of monthly mean ozone merged from six satellite instruments. The Upper Atmospheric Data Support Team has been providing science and data support to assist users in accessing and using the upper atmospheric data products. A number of tools for data access, subsetting, reprojection and mapping of orbital (Level-2) products, visualization of global gridded (Level-3) products, and data analysis have been developed at the Goddard DAAC and are freely available to the data user (http://daac.gsfc.nasa.gov) This presentation will provide highlights of the standard and value-added ozone and ancillary products, and the data services provided by the DAAC Upper Atmosphere Data Support Team.

  11. Long term low latitude and high elevation cosmogenic 3He production rate inferred from a 107 ka-old lava flow in northern Chile; 22°S-3400 m a.s.l.

    NASA Astrophysics Data System (ADS)

    Delunel, Romain; Blard, Pierre-Henri; Martin, Léo C. P.; Nomade, Sébastien; Schlunegger, Fritz

    2016-07-01

    Available geological calibration sites used to estimate the rate at which cosmogenic 3He is produced at the Earth's surface are mostly clustered in medium to high latitudes. Moreover, most of them have exposure histories shorter than tens of thousands of years. This lack of sites prevents a qualitative assessment of available production models used to convert cosmogenic 3He concentrations into exposure ages and/or denudation rates. It thus limits our ability to take into account the atmospheric, geomagnetic and solar modulation conditions that might have affected the production of cosmogenic nuclides in the past for longer exposure histories and in low latitude regions. We present the cosmogenic 3He production rate inferred from a new geological calibration site located in northern Chile. Five samples were collected on the surface of the largest and best-preserved lava flow of the San Pedro volcano (21.934°S-68.510°W-3390 m a.s.l.), which displays pristine crease-structure features. 40Ar/39Ar dating yields a reliable plateau age of 107 ± 12 ka for the eruption of this lava flow. Eight pyroxene aliquots separated from the surface samples yield a weighted average cosmogenic 3He concentration of 99.3 ± 1.2 Mat g-1 from which a local cosmogenic 3He production rate of 928 ± 101 at g-1 yr-1 is calculated. The local production rate is then scaled to a sea level high latitude (SLHL) reference position using different combinations of geographic spatialization schemes, atmosphere models and geomagnetic field reconstructions, yielding SLHL production rates between 103 ± 11 and 130 ± 14 at g-1 yr-1 consistent with the most recent estimates available from the literature. Finally, we use the same scaling frameworks to re-evaluate the mean global-scale cosmogenic 3He production rate in olivine and pyroxene minerals at 120 ± 16 at g-1 yr-1 from the compilation of previously published calibration datasets.

  12. Extreme events in total ozone over Arosa: Application of extreme value theory and fingerprints of atmospheric dynamics and chemistry and their effects on mean values and long-term changes

    NASA Astrophysics Data System (ADS)

    Rieder, Harald E.; Staehelin, Johannes; Maeder, Jörg A.; Peter, Thomas; Ribatet, Mathieu; Davison, Anthony C.; Stübi, Rene; Weihs, Philipp; Holawe, Franz

    2010-05-01

    ón, Mt. Pinatubo). Furthermore, atmospheric loading in ozone depleting substances lead to a continuous modification of column ozone in the northern hemisphere also with respect to extreme values (partly again in connection with polar vortex contributions). It is shown that application of extreme value theory allows the identification of many more such fingerprints than conventional time series analysis of annual and seasonal mean values. Especially, the analysis shows the strong influence of dynamics, revealing that even moderate ENSO and NAO events have a discernible effect on total ozone (Rieder et al., 2010b). Overall the presented new extremes concept provides new information on time series properties, variability, trends and the influence of dynamics and chemistry, complementing earlier analyses focusing only on monthly (or annual) mean values. References: Coles, S.: An Introduction to Statistical Modeling of Extreme Values, Springer Series in Statistics, ISBN:1852334592, Springer, Berlin, 2001. Ribatet, M.: POT: Modelling peaks over a threshold, R News, 7, 34-36, 2007. Rieder ,H.E., Staehelin, J., Maeder, J.A., Ribatet, M., Stübi, R., Weihs, P., Holawe, F., Peter, T., and A.D., Davison (2010): Extreme events in total ozone over Arosa - Part I: Application of extreme value theory, to be submitted to ACPD. Rieder, H.E., Staehelin, J., Maeder, J.A., Ribatet, M., Stübi, R., Weihs, P., Holawe, F., Peter, T., and A.D., Davison (2010): Extreme events in total ozone over Arosa - Part II: Fingerprints of atmospheric dynamics and chemistry and effects on mean values and long-term changes, to be submitted to ACPD. Staehelin, J., Renaud, A., Bader, J., McPeters, R., Viatte, P., Hoegger, B., Bugnion, V., Giroud, M., and Schill, H.: Total ozone series at Arosa (Switzerland): Homogenization and data comparison, J. Geophys. Res., 103(D5), 5827-5842, doi:10.1029/97JD02402, 1998a. Staehelin, J., Kegel, R., and Harris, N. R.: Trend analysis of the homogenized total ozone series of

  13. Mental Health in Long Term Care Settings.

    ERIC Educational Resources Information Center

    Shore, Herbert

    1978-01-01

    There are many ways in which long-term care facilities attempt to cope with the mental health problems of the elderly. The author reviews five factors crucial to effective care for the aged in these facilities. (Author/RK)

  14. Asthma Medicines: Long-Term Control

    MedlinePlus

    ... Español Text Size Email Print Share Asthma Medicines: Long-term Control Page Content Article Body Corticosteroids Synthetic ... and sprinkle forms are available for young children. Long-Acting Beta2-Agonists Medications in the beta 2 - ...

  15. Long Term Effects of Food Poisoning

    MedlinePlus

    ... develop chronic arthritis. Brain and nerve damage A Listeria infection can lead to meningitis, an inflammation of ... brain. If a newborn infant is infected with Listeria , long-term consequences may include mental retardation, seizures, ...

  16. Measurements of Humidity in the Atmosphere: Validation Experiments (MOHAVE I and MOHAVE II). Results Overview and Implication for the Long-Term Lidar Monitoring of Water Vapor in the UT/LS

    NASA Technical Reports Server (NTRS)

    Leblanc, Thierry; McDermid, I. S.; Vomel, H.; Whiteman, D.; Twigg, Larry; McGee, T. G.

    2008-01-01

    1. MOHAVE+MOHAVE II = very successful. 2. MOHAVE -> Fluorescence was found to be inherent to all three participating lidars. 3. MOHAVE II -> Fluorescence was removed and agreement with CFH was extremely good up to 16-18 km altitude. 4. MOHAVE II -> Calibration tests revealed unsuspected shortfalls of widely used techniques, with important implications for their applicability to longterm measurements. 5. A factor of 5 in future lidar signal-to-noise ratio is reasonably achievable. When this level is achieved water vapor Raman lidar will become a key instrument for the long-term monitoring of water vapor in the UT/LS

  17. Is guava phenolic metabolism influenced by elevated atmospheric CO2?

    PubMed

    Mendes de Rezende, Fernanda; Pereira de Souza, Amanda; Silveira Buckeridge, Marcos; Maria Furlan, Cláudia

    2015-01-01

    Seedlings of Psidium guajava cv. Pedro Sato were distributed into four open-top chambers: two with ambient CO(2) (∼390 ppm) and two with elevated CO(2) (∼780 ppm). Monthly, five individuals of each chamber were collected, separated into root, stem and leaves and immediately frozen in liquid nitrogen. Chemical parameters were analyzed to investigate how guava invests the surplus carbon. For all classes of phenolic compounds analyzed only tannins showed significant increase in plants at elevated CO(2) after 90 days. There was no significant difference in dry biomass, but the leaves showed high accumulation of starch under elevated CO(2). Results suggest that elevated CO(2) seems to be favorable to seedlings of P. guajava, due to accumulation of starch and tannins, the latter being an important anti-herbivore substance. PMID:25129845

  18. Experimental protocols and preparations to study respiratory long term facilitation

    PubMed Central

    Mateika, Jason H.; Sandhu, Kulraj S.

    2011-01-01

    Respiratory long-term facilitation is a form of neuronal plasticity that is induced following exposure to intermittent hypoxia. Long-term facilitation is characterized by a progressive increase in respiratory motor output during normoxic periods that separate hypoxic episodes and by a sustained elevation in respiratory activity for up to 90 min after exposure to intermittent hypoxia. This phenomenon is associated with increases in phrenic, hypoglossal or carotid sinus nerve inspiratory-modulated discharge. The examination of long-term facilitation has been steadily ongoing for approximately 3 decades. During this period of time a variety of animal models (e.g. cats, rats and humans), experimental preparations and intermittent hypoxia protocols have been used to study long-term facilitation. This review is designed to summarize the strengths and weaknesses of the models, preparations and protocols that have been used to study LTF over the past 30 years. The review is divided into two primary sections. Initially, the models and protocols used to study LTF in animals other than humans will be discussed, followed by a section specifically focused on human studies. Each section will begin with a discussion of various factors that must be considered when selecting an experimental preparation and intermittent hypoxia protocol to examine LTF. Model and protocol design recommendations will follow, with the goal of presenting a prevailing model and protocol that will ultimately ensure standardized comparisons across studies. PMID:21292044

  19. Effects of elevated atmospheric CO{sub 2} concentrations and water stress on field-grown maize

    SciTech Connect

    Surano, K.A.; Kercher, J.R.

    1993-10-01

    Global atmospheric carbon dioxide (CO{sub 2}) concentrations are continuing to increase and will probably double during the next century. The effects of such an increase are of global concern. Carbon dioxide-induced climate changes may result in reduced precipitation in major agricultural areas. The potential therefore exists for severe CO{sub 2}-induced water-stress effects on agriculture. This set of studies determined the effects of long-term elevated atmospheric CO{sub 2} concentrations and severe water stress on biomass production, evapotranspiration, water-use efficiency (WUE), water potential, photosynthesis, stomatal conductance, morphology and phenology of maize grown under field conditions. Plants were grown at one of four daytime mean CO{sub 2} concentrations (348, 431, 506 or 656 {mu}LL{sup {minus}1}) in open-top field exposure chambers and at one of two levels of available water (well-watered or 50% of well-watered). This report is organized into 4 chapters followed by appendices. Separate abstracts were prepared for each of the four chapters: (1) biomass production and water-use efficiency, (2) gas exchange and water potential, (3) morphology and phenology, and (4) and elemental analyses. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  20. Long-term evolution of anthropogenic heat fluxes into a subsurface urban heat island.

    PubMed

    Menberg, Kathrin; Blum, Philipp; Schaffitel, Axel; Bayer, Peter

    2013-09-01

    Anthropogenic alterations in urban areas influence the thermal environment causing elevated atmospheric and subsurface temperatures. The subsurface urban heat island effect is observed in several cities. Often shallow urban aquifers exist with thermal anomalies that spread laterally and vertically, resulting in the long-term accumulation of heat. In this study, we develop an analytical heat flux model to investigate possible drivers such as increased ground surface temperatures (GSTs) at artificial surfaces and heat losses from basements of buildings, sewage systems, subsurface district heating networks, and reinjection of thermal wastewater. By modeling the anthropogenic heat flux into the subsurface of the city of Karlsruhe, Germany, in 1977 and 2011, we evaluate long-term trends in the heat flux processes. It revealed that elevated GST and heat loss from basements are dominant factors in the heat anomalies. The average total urban heat flux into the shallow aquifer in Karlsruhe was found to be ∼759 ± 89 mW/m(2) in 1977 and 828 ± 143 mW/m(2) in 2011, which represents an annual energy gain of around 1.0 × 10(15) J. However, the amount of thermal energy originating from the individual heat flux processes has changed significantly over the past three decades. PMID:23895264

  1. Characteristics of long-term variation in the amlitude of the geomagnetic solar quiet (Sq) daily variation using the Inter-university Upper atmosphere Gobal Observation NETwork (IUGONET) data analysis system

    NASA Astrophysics Data System (ADS)

    Shinbori, A.; Koyama, Y.; Nose, M.; Hori, T.; Otsuka, Y.; Yatagai, A. I.

    2014-12-01

    Characteristics of long-term variation in the amplitude of solar quiet geomagnetic field daily variation (Sq) have been investigated using 1-hour geomagnetic field data obtained from 69 geomagnetic stations in a period of 1947-2013. In the present data analysis, we took advantage of the IUGONET data analysis system. The Sq amplitude clearly showed a 10-12 year solar activity dependence and it tended to enhance during each solar maximum. During the minimum of solar cycle 23/24 in 2008-2009, the Sq amplitude became the smallest in the investigated period. The relationship between the solar F10.7 index and Sq amplitude is approximately linear but 64 percent of geomagnetic stations show a weak nonlinear dependence on the solar F10.7 index. In order to remove the effect of solar activity seen in the long-term variation of the Sq amplitude, we calculated a linear or second order fitting curve between the solar F10.7 index and Sq amplitude during 1947-2013, and examined the residual Sq amplitude, which is defined as the deviation from the fitting curve. As a result, a majority of the trends in the residual Sq amplitude that passed through a trend test showed a negative value in a wide region. This tendency was relatively strong in Europe, India, the eastern part of Canada, and New Zealand. The relationship between the magnetic field intensity and residual Sq amplitude showed an anti-correlation for about 71 percent of geomagnetic stations. On the other hand, the residual Sq amplitude in the equatorial station (Addis Ababa) was anti-correlated with the absolute value of the magnetic field inclination. This implies the movement of the equatorial electrojet due to the secular variation of the ambient magnetic field.

  2. Regional and temporal differences in nitrate trends discerned from long-term water quality monitoring data

    USGS Publications Warehouse

    Stets, Edward G.; Kelly, Valerie J.; Crawford, Charles G.

    2015-01-01

    Riverine nitrate (NO3) is a well-documented driver of eutrophication and hypoxia in coastal areas. The development of the elevated river NO3 concentration is linked to anthropogenic inputs from municipal, agricultural, and atmospheric sources. The intensity of these sources has varied regionally, through time, and in response to multiple causes such as economic drivers and policy responses. This study uses long-term water quality, land use, and other ancillary data to further describe the evolution of river NO3 concentrations at 22 monitoring stations in the United States (U.S.). The stations were selected for long-term data availability and to represent a range of climate and land-use conditions. We examined NO3 at the monitoring stations, using a flow-weighting scheme meant to account for interannual flow variability allowing greater focus on river chemical conditions. River NO3 concentration increased strongly during 1945-1980 at most of the stations and have remained elevated, but stopped increasing during 1981-2008. NO3 increased to a greater extent at monitoring stations in the Midwest U.S. and less so at those in the Eastern and Western U.S. We discuss 20th Century agricultural development in the U.S. and demonstrate that regional differences in NO3 concentration patterns were strongly related to an agricultural index developed using principal components analysis. This unique century-scale dataset adds to our understanding of long-term NO3 patterns in the U.S.

  3. Long-term Multiwavelength Observations of Polars

    NASA Astrophysics Data System (ADS)

    Santana, Joshua; Mason, Paul A.

    2016-06-01

    Polars are cataclysmic variables with the highest magnetic field strengths (10-250 MG). Matter is accreted after being funneled by the strong magnetic field of the white dwarf. We perform a meta-study of multi-wavelength data of polars. Many polars have been observed in surveys, such as SDSS, 2MASS, ROSAT, just to name a few. Some polars have now been detected by the JVLA, part of an expanding class of radio CVs. A large subset of polars have long-term optical light curves from CRTS and AAVSO. We suggest that the long term light curves of polars display a variety of signature behaviors and may be grouped accordingly. Additional characteristics such a binary period, magnetic field strengths, X-ray properties, and distance estimates are examined in context with long-term observations.

  4. Scenarios for long-term analysis

    SciTech Connect

    Wolbers, Stephen; /Fermilab

    2009-01-01

    Data Preservation and Long-Term Analysis of High Energy Physics (HEP) Experiments data is described and summarized in this talk. The summary covers information presented at the First Workshop on Data Preservation and Long-Term Analysis. Experiments representing e{sup +}e{sup -} collisions (LEP, B Factories and CLEO), ep collisions (H1 and ZEUS), p{bar p} collisions (CDF and D0) and others presented interesting information related to utilizing the large datasets collected over many years at these HEP facilities. Many questions and issues remain to be explored.

  5. Long-Term Use of Benzodiazepines

    PubMed Central

    Potts, Nicholas L.S.; Krishnan, K. Ranga R.

    1992-01-01

    Problems associated with physical dependence and abuse of benzodiazepines by a small percentage of patients have reduced their popularity from the most commonly prescribed psychoactive drug in the 1970s to being prescribed for mainly short periods. Patients who benefit from long-term benzodiazepine use are nearly ignored by the medical community as a whole. This article details what patient population can improve from long-term benzodiazepine therapy, the risks and benefits of treatment, and how to select appropriate candidates. PMID:21229127

  6. Long-term Outcomes after Severe Shock

    PubMed Central

    Pratt, Cristina M.; Hirshberg, Eliotte L.; Jones, Jason P.; Kuttler, Kathryn G.; Lanspa, Michael J.; Wilson, Emily L.; Hopkins, Ramona O.; Brown, Samuel M.

    2014-01-01

    Background Severe shock is a life-threatening condition with very high short-term mortality. Whether the long-term outcomes among survivors of severe shock are similar to long-term outcomes of other critical illness survivors is unknown. We therefore sought to assess long-term survival and functional outcomes among 90-day survivors of severe shock and determine whether clinical predictors were associated with outcomes. Methods Seventy-six patients who were alive 90 days after severe shock (received ≥1 mcg/kg/min of norepinephrine equivalent) were eligible for the study. We measured three-year survival and long-term functional outcomes using the Medical Outcomes Study 36-Item Short-Form Health Survey, the EuroQOL 5-D-3L, the Hospital Anxiety and Depression Scale, the Impact of Event Scale-Revised and an employment instrument. We also assessed the relationship between in-hospital predictors and long-term outcomes. Results The mean long-term survival was 5.1 years: 82% (62/76) of patients survived, of whom 49 were eligible for follow-up. Patients who died were older than patients who survived. Thirty-six patients completed a telephone interview a mean of five years after hospital admission. The patients’ Physical Functioning scores were below US population norms (p<0.001), whereas mental health scores were similar to population norms. Nineteen percent of the patients had symptoms of depression, 39% had symptoms of anxiety and 8% had symptoms of posttraumatic stress disorder. Thirty-six percent were disabled, and 17% were working full time. Conclusions Early survivors of severe shock had a high three-year survival rate. Patients’ long term physical and psychological outcomes were similar to those reported for cohorts of less severely ill ICU survivors. Anxiety and depression were relatively common, but only a few patients had symptoms of posttraumatic stress disorder. This study supports the observation that acute illness severity does not determine long-term

  7. Response of a tundra ecosystem to elevated atmospheric carbon dioxide and CO{sub 2}-induced climate change. Annual technical report

    SciTech Connect

    Oechel, W.C.

    1992-04-01

    Northern ecosystems contain up to 455 Gt of C in the soil active layer and upper permafrost. The soil carbon in these layers is equivalent to approximately 60% of the carbon currently in the atmosphere as CO{sub 2}. Much of this carbon is stored in the soil as dead organic matter. Its fate is subject to the net effects of global change on the plant and soil systems of northern ecosystems. The arctic alone contains about 60 Gt C, 90% of which is present in the soil active layer and upper permafrost. The arctic is assumed to have been a sink for CO{sub 2} during the historic and recent geologic past. The arctic has the potential to be a very large, long-term source or sink of CO{sub 2} with respect to the atmosphere. In situ experimental manipulations of atmospheric CO{sub 2}, indicated that there is little effect of elevated atmospheric CO{sub 2} on leaf level photosynthesis or whole-ecosystem CO{sub 2} flux over the course of weeks to years, respectively. However, there may be longer- term ecosystem responses to elevated CO{sub 2} that could ultimately affect ecosystem CO{sub 2} balance. In addition to atmospheric CO{sub 2}, climate may affect net ecosystem carbon balance. Recent results indicate that the arctic has become a source of CO{sub 2} to the atmosphere. This change coincides with recent climatic variation in the arctic, and suggests a positive feedback of arctic ecosystems on atmospheric CO{sub 2} and global change. The research proposed in this application has four principal aspects: (A) Long-term response of arctic plants and ecosystems to elevated atmospheric CO{sub 2}; (B) Circumpolar patterns of net ecosystem CO{sub 2} flux; (C) In situ controls by temperature and moisture on net ecosystem CO{sub 2} flux; (D) Scaling of CO{sub 2} flux from plot, to landscape, to regional scales (In conjunction with research proposed for NSF support).

  8. Elevated atmospheric CO2 and O3 differentially alter nitrogen acquisition in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both CO2 and ozone (O3) concentrations in the atmosphere have increased over the past 50 years and are predicted to rise continually during this century. Elevated CO2 usually stimulates while elevated O3 often inhibits plant photosynthesis and primary production. Whether these changes are partly re...

  9. Long-term Studies of Marine Halogen Release

    NASA Astrophysics Data System (ADS)

    Tschritter, J.; Holla, R.; Frieß, U.; Platt, U.

    2009-04-01

    Institute of Enviromental Physics, Heidelberg, Germany. Long term measurements of atmospheric trace gases using multi-axis DOAS instruments are pursued at the new SOLAS observatory on the island of Sao Vicente, (Cape Verde). This research is part of the SOPRAN (Surface Ocean Processes in the ANthropocene) project (Fördernummer:03F0462F). Reactive halogen species (RHS) such as bromine- and iodine- containing species play major roles in the chemistry of ozone in both the troposphere and lower stratosphere and thus possibly influence the ozone budget on a global scale. In addition iodine-species emitted from the ocean surface have been shown to be responsible for the production of new atmospheric particles in the marine boundary layer. This may have an effect on cloud formation and radiation transfer on local and global scales. Long term measurements of RHS abundances will help to identify their key regions and processes for formation. A new long term Multi-MAX-DOAS instrument has been installed at the SOLAS observatory on the island of Sao Vicente, (Cape Verde). The main focus of these unique measurements is the investigation of reactive halogen chemistry in the subtropical marine boundary layer based on measurements of BrO, IO, and possibly OIO. Because of its wide spectral range also the use for O4-retrievals to gain aerosol profiles is possible. IO has been detected with mixing ratios up to 1.3 ppt. For BrO an upper limit of 2 ppt could be determined.

  10. Long Term Care Aide. Course Outline.

    ERIC Educational Resources Information Center

    Wilbee, Judy

    This course outline is intended to assist the instructor in the development of a curriculum for a long-term care aide program by specifying one component of the curriculum--the objectives. These objectives, or competencies expected as outcomes for student performance on completion of the program, describe the capabilities an individual must…

  11. Who Recommends Long-Term Care Matters

    ERIC Educational Resources Information Center

    Kane, Robert L.; Bershadsky, Boris; Bershadsky, Julie

    2006-01-01

    Purpose: Making good consumer decisions requires having good information. This study compared long-term-care recommendations among various types of health professionals. Design and Methods: We gave randomly varied scenarios to a convenience national sample of 211 professionals from varying disciplines and work locations. For each scenario, we…

  12. Long-term fixed income market structure

    NASA Astrophysics Data System (ADS)

    Grilli, Luca

    2004-02-01

    Long-term fixed income market securities present a strong positive correlation in daily returns. By using a metrical approach and considering “modified” time series, I show how it is possible to show a more complex structure which depends strictly on the maturity date.

  13. Professionalism in Long-Term Care Settings

    ERIC Educational Resources Information Center

    Lubinski, Rosemary

    2006-01-01

    Speech-language pathologists who serve elders in a variety of long-term care settings have a variety of professional skills and responsibilities. Fundamental to quality service is knowledge of aging and communication changes and disorders associated with this process, institutional alternatives, and the changing nature of today's elders in…

  14. LONG TERM HYDROLOGICAL IMPACT ASSESSMENT (LTHIA)

    EPA Science Inventory

    LTHIA is a universal Urban Sprawl analysis tool that is available to all at no charge through the Internet. It estimates impacts on runoff, recharge and nonpoint source pollution resulting from past or proposed land use changes. It gives long-term average annual runoff for a lan...

  15. NATIONAL LONG TERM CARE SURVEY (NLTCS)

    EPA Science Inventory

    National Long Term Care Surveys (NLTCS) are surveys of the entire aged population with a particular emphasis on the functionally impaired. Longitudinal study of the health and well-being of elderly Americans. Information about the population of chronically disabled elderly person...

  16. Long-Term Memory and Learning

    ERIC Educational Resources Information Center

    Crossland, John

    2011-01-01

    The English National Curriculum Programmes of Study emphasise the importance of knowledge, understanding and skills, and teachers are well versed in structuring learning in those terms. Research outcomes into how long-term memory is stored and retrieved provide support for structuring learning in this way. Four further messages are added to the…

  17. Long-Term Stability of Social Participation

    ERIC Educational Resources Information Center

    Hyyppa, Markku T.; Maki, Juhani; Alanen, Erkki; Impivaara, Olli; Aromaa, Arpo

    2008-01-01

    The long-term stability of social participation was investigated in a representative urban population of 415 men and 579 women who had taken part in the nationwide Mini-Finland Health Survey in the years 1978-1980 and were re-examined 20 years later. Stability was assessed by means of the following tracking coefficients: kappa, proportion of…

  18. GEWEX Contributions to Long Term Global Data Sets

    NASA Astrophysics Data System (ADS)

    van Oevelen, P.; Kummerow, C.; Schulz, J.

    2012-04-01

    The Global Energy and Water Cycle Experiment (GEWEX) as part of the World Climate Research Programme (WCRP) has a long history in the support and development of long term global data sets for energy and water cycle research based upon primarily earth observation data. The main panel under GEWEX responsible for these data sets is the GEWEX Data and Assessments Panel (GDAP) formally well known as the GEWEX Radiation Panel (GRP). GDAP has as its primary goal to guide production and evaluation of long term, globally complete atmospheric and surface water and energy budget products, including radiation, clouds, aerosols, precipitation and surface turbulent fluxes. In this presentation an overview of the history and future of the various data sets produced under GDAP is given along with an outlook on the individual data sets as well as the Integrated Data set.

  19. Atmospheric deposition and watershed nitrogen export along an elevational gradient in the Catskill Mountains, New York

    USGS Publications Warehouse

    Lawrence, G.B.; Lovett, Gary M.; Baevsky, Y.H.

    2000-01-01

    Cumulative effects of atmospheric N deposition may increase N export from watersheds and contribute to the acidification of surface waters, but natural factors (such as forest productivity and soil drainage) that affect forest N cycling can also control watershed N export. To identify factors that are related to stream-water export of N, elevational gradients in atmospheric deposition and natural processes were evaluated in a steep, first-order watershed in the Catskill Mountains of New York, from 1991 to 1994. Atmospheric deposition of SO4/2-, and probably N, increased with increasing elevation within this watershed. Stream-water concentrations of SO4/2- increased with increasing elevation throughout the year, whereas stream-water concentrations of NO3/- decreased with increasing elevation during the winter and spring snowmelt period, and showed no relation with elevation during the growing season or the fall. Annual export of N in stream water for the overall watershed equaled 12% to 17% of the total atmospheric input on the basis of two methods of estimation. This percentage decreased with increasing elevation, from about 25% in the lowest subwatershed to 7% in the highest subwatershed; a probable result of an upslope increase in the thickness of the surface organic horizon, attributable to an elevational gradient in temperature that slows decomposition rates at upper elevations. Balsam fir stands, more prevalent at upper elevations than lower elevations, may also affect the gradient of subwatershed N export by altering nitrification rates in the soil. Variations in climate and vegetation must be considered to determine how future trends in atmospheric deposition will effect watershed export of nitrogen.

  20. COMBINED EFFECTS OF ELEVATED ATMOSPHERIC CARBON DIOXIDE AND OZONE ON SOYBEAN WHOLE-PLANT WATER USE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With increasing atmospheric concentrations of trace gases such as carbon dioxide and ozone, a critical issue is how these changes will affect agricultural hydrologic cycles. To address an important part of this question, a study was undertaken to test the effects of elevated atmospheric carbon diox...

  1. Elevated atmospheric carbon dioxide: Effects on tritrophic interactions

    SciTech Connect

    Roth, S.K.; Lindroth, R.L. )

    1994-06-01

    We examined how CO[sub 2]-mediated changes in tree chemistry affect performance of the gypsy moth (Lymantria dispar) and its suitability as a host for the parasitoid Cotesia melanoscelus. Four species of deciduous trees were grown under ambient or elevated CO[sub 2] conditions, and foliage was fed to gypsy moths in two separate bioassays. In the first, we measured performance (i.e., growth rates) of control and parasitized gypsy moth larvae for the duration of the third stadium. In the second, we assessed parasitoid performance in relation to quality of the host larvae. We found that parasitized gypsy moth larvae on all diets grew more slowly and suffered reduced food processing efficiencies relative to control larvae. The magnitude of growth suppression was greater under elevated CO[sub 2] conditions. Parasitoid performance varied in relation to host plant species but not in relation to CO[sub 2] environment. These results will be interpreted in relation to tree chemistry.

  2. Can recent increases in forest biomass be translated into long-term carbon storage?

    NASA Astrophysics Data System (ADS)

    Weng, E.; Pacala, S. W.

    2013-12-01

    The biomass of forests across the globe is rapidly increasing in the past decades. The rates of biomass accumulations over years/decades are much higher than those derived from long-term chronosequences, which has been taken as the evidence of elevated carbon sink in responses to increasing atmospheric CO2 and climate change. But there is a gap between increases in forest biomass over a short-term and the biomass carbon sequestration for a long period of time in a stochastic dynamic system like forests characterized by 'slow in - fast out' processes, because the disturbances happened at century time scales may erase the accumulated biomass over decades. According to our mathematical analysis, in such a system, the short-term biomass accumulation rate should be always higher than that at long-term scale. It is unknown that how many short-term increases in biomass can be translated into long-term trends at given disturbance regimes. In this paper, we derived an analytical model linking the short-term biomass increase to long-term biomass accumulation at given disturbance regimes. And, based on the analytical solutions of this model, we analyzed the chronosequence and time series biomass data of the temperate forests of Northeastern America obtained from literature and forest inventory (FIA data). Our results show the current biomass increase rates cannot maintain statistically significant higher trends of biomass accumulation than those derived from chronosequences (i.e., historic long-term rates) at current disturbance regimes. And, the potential of carbon storage in live biomass doesn't increase over past decade due to increasing mortality rates in the forests with high biomass. If disturbances become more frequent and severe as predicted by other studies, forest carbon storage will be reduced in the future. This analysis suggests that the temperate forests in Northeastern America will not store so much carbon as expected based on the trends of increasing biomass

  3. On the relationship between total ozone and atmospheric dynamics and chemistry at mid-latitudes - Part 2: The effects of the El Niño/Southern Oscillation, volcanic eruptions and contributions of atmospheric dynamics and chemistry to long-term total ozone changes

    NASA Astrophysics Data System (ADS)

    Rieder, H. E.; Frossard, L.; Ribatet, M.; Staehelin, J.; Maeder, J. A.; Di Rocco, S.; Davison, A. C.; Peter, T.; Weihs, P.; Holawe, F.

    2013-01-01

    We present the first spatial analysis of "fingerprints" of the El Niño/Southern Oscillation (ENSO) and atmospheric aerosol load after major volcanic eruptions (El Chichón and Mt. Pinatubo) in extreme low and high (termed ELOs and EHOs, respectively) and mean values of total ozone for the northern and southern mid-latitudes (defined as the region between 30° and 60° north and south, respectively). Significant influence on ozone extremes was found for the warm ENSO phase in both hemispheres during spring, especially towards low latitudes, indicating the enhanced ozone transport from the tropics to the extra-tropics. Further, the results confirm findings of recent work on the connection between the ENSO phase and the strength and extent of the southern ozone "collar". For the volcanic eruptions the analysis confirms findings of earlier studies for the northern mid-latitudes and gives new insights for the Southern Hemisphere. The results provide evidence that the negative effect of the eruption of El Chichón might be partly compensated by a strong warm ENSO phase in 1982-1983 at southern mid-latitudes. The strong west-east gradient in the coefficient estimates for the Mt. Pinatubo eruption and the analysis of the relationship between the AAO and ENSO phase, the extent and the position of the southern ozone "collar" and the polar vortex structure provide clear evidence for a dynamical "masking" of the volcanic signal at southern mid-latitudes. The paper also analyses the contribution of atmospheric dynamics and chemistry to long-term total ozone changes. Here, quite heterogeneous results have been found on spatial scales. In general the results show that EESC and the 11-yr solar cycle can be identified as major contributors to long-term ozone changes. However, a strong contribution of dynamical features (El Niño/Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Antarctic Oscillation (AAO), Quasi-Biennial Oscillation (QBO)) to ozone variability and

  4. On the relationship between total ozone and atmospheric dynamics and chemistry at mid-latitudes - Part 2: The effects of the El Niño/Southern Oscillation, volcanic eruptions and contributions of atmospheric dynamics and chemistry to long-term total ozone changes

    NASA Astrophysics Data System (ADS)

    Rieder, H. E.; Frossard, L.; Ribatet, M.; Staehelin, J.; Maeder, J. A.; Di Rocco, S.; Davison, A. C.; Peter, T.; Weihs, P.; Holawe, F.

    2012-05-01

    We present the first spatial analysis of "fingerprints" of the El Niño/Southern Oscillation (ENSO) and atmospheric aerosol load after major volcanic eruptions (El Chichón and Mt. Pinatubo) in extreme low and high (termed ELOs and EHOs, respectively) and mean values of total ozone for the northern and southern mid-latitudes (defined as the region between 30° and 60° north and south, respectively). Significant influence on ozone extremes was found for the warm ENSO phase in both hemispheres during spring, especially towards low latitudes, indicating the enhanced ozone transport from the tropics to the extra-tropics. Further, the results confirm findings of recent work on the connection between the ENSO phase and the strength and extent of the southern ozone "collar". For the volcanic eruptions the analysis confirms findings of earlier studies for the northern mid-latitudes and gives new insights for the Southern Hemisphere. The results provide evidence that the negative effect of the eruption of El Chichón might be partly compensated by a strong warm ENSO phase in 1982-83 at southern mid-latitudes. The strong west-east gradient in the coefficient estimates for the Mt. Pinatubo eruption and the analysis of the relationship between the AAO and ENSO phase, the extent and the position of the southern ozone "collar" and the polar vortex structure provide clear evidence for a dynamical "masking" of the volcanic signal at southern mid-latitudes. The paper also analyses the contribution of atmospheric dynamics and chemistry to long-term total ozone changes. Here, quite heterogeneous results have been found on spatial scales. In general the results show that EESC and the 11-yr solar cycle can be identified as major contributors to long-term ozone changes. However, a strong contribution of dynamical features (El Niño/Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Antarctic Oscillation (AAO), Quasi-Biennial Oscillation (QBO)) to ozone variability and

  5. Long term mortality in burned children

    PubMed Central

    Stamboulian, Daniel; Lede, Roberto

    2015-01-01

    Studies about risk factors for mortality in burn children are scarce and are even less in the follow up of this population across time. Usually, after complete event attendance, children are not follow-up as risk patients, burn injury affects all facets of life. Integration of professionals from different disciplines has enabled burn centers to develop collaborative methods of assessing the quality of care delivered to patients with burns. In this editorial we comment the paper of Duke et al. The authors highlight the importance of maintaining a long-term monitoring of children who suffered burns. The importance of this original study is to promote the reconsideration of clinical guides of long-term follow-up of burn patients. PMID:26835375

  6. Long term mortality in burned children.

    PubMed

    Rosanova, María Teresa; Stamboulian, Daniel; Lede, Roberto

    2015-07-01

    Studies about risk factors for mortality in burn children are scarce and are even less in the follow up of this population across time. Usually, after complete event attendance, children are not follow-up as risk patients, burn injury affects all facets of life. Integration of professionals from different disciplines has enabled burn centers to develop collaborative methods of assessing the quality of care delivered to patients with burns. In this editorial we comment the paper of Duke et al. The authors highlight the importance of maintaining a long-term monitoring of children who suffered burns. The importance of this original study is to promote the reconsideration of clinical guides of long-term follow-up of burn patients. PMID:26835375

  7. Long-term safety of retinoid therapy.

    PubMed

    Vahlquist, A

    1992-12-01

    The concern about long-term toxicity of oral synthetic retinoids has developed because many patients, especially those with genodermatoses, require lifelong therapy. Several organ systems are at risk, especially the hepatic, skeletal, and cardiovascular systems. Although acute hepatotoxicity is a rare side effect of etretinate and acitretin therapy, prospective studies have not demonstrated chronic liver toxicity. The frequency of bone changes induced by retinoids is difficult to estimate, because this adverse effect is usually asymptomatic and requires x-ray or scintigraphic examination for detection. Atherosclerosis develops in many patients who receive long-term retinoid therapy, but the extent to which the process is aggravated by drug-induced hyperlipidemia is not known. Many patients have now been treated with either etretinate or isotretinoin continuously for as many as 15 years and have not developed any signs of severe chronic toxicity. However, continued intense surveillance is recommended for patients expected to require lifelong therapy. PMID:1460122

  8. [Taiwan long-term care insurance and the evolution of long-term care in Japan].

    PubMed

    Huang, Hui-Wen; Liu, Shu-Hui; Pai, Yu-Chu

    2010-08-01

    The proportion of elderly (65 years of age and older) in Taiwan has exceeded 10% since 2008. With more elderly, the number of patients suffering from dementia and disabilities has also been rapidly increasing. Japan also has been facing increasing demand for long-term care due to an aging society. Prior to 2000, social welfare programs in Japan, working to cope with changing needs, typically provided insufficient services, and geriatric patients were hospitalized unnecessarily, wasting medical resources and causing undue patient hardship. In response, Japan launched its long-term care insurance program in April 2000. Under the program, city, town and village-based organizations should take responsibility for providing care to the elderly in their place of residence. The program significantly improved previous financial shortfalls and long-term care supply and demand has been met by existing social welfare organization resources. In Taiwan, the provision of long-term care by county / city authorities has proven inconsistent, with performance deemed poor after its first decade of long-term care operations. Service was found to be affected by differences in available resources and insufficient long-term care administration. The cultures of Taiwan and Japan are similar. The authors visited the Japan Long-Term Care Insurance Institute in August 2009. Main issues involved in the implementation and evolution of the Japan long-term Care Insurance are reported on in this paper. We hope such may be useful information to those working to develop long-term care programs in Taiwan. PMID:20661859

  9. Long-term orbital lifetime predictions

    NASA Astrophysics Data System (ADS)

    Dreher, P. E.; Lyons, A. T.

    1990-10-01

    Long-term orbital lifetime predictions are analyzed. Predictions were made for three satellites: the Solar Max Mission (SMM), the Long Duration Exposure Facility (LDEF), and the Pegasus Boiler Plate (BP). A technique is discussed for determining an appropriate ballistic coefficient to use in the lifetime prediction. The orbital decay rate should be monitored regularly. Ballistic coefficient updates should be done whenever there is a significant change in the actual decay rate or in the solar activity prediction.

  10. Long-term sequelae of electrical injury

    PubMed Central

    Wesner, Marni L.; Hickie, John

    2013-01-01

    Abstract Objective To summarize the current evidence-based knowledge about the long-term sequelae of injuries from electrical current. Quality of evidence MEDLINE was searched for English-language articles published in the past 20 years using the following search terms: electrical, injuries, wound, trauma, accident, sequelae, long-term, follow-up, and aftereffects. For obvious reasons, it is unethical to randomly study electrical injury in controlled clinical trials. By necessity, this topic is addressed in less-rigorous observational and retrospective work and case studies. Therefore, the strength of the literature pertaining to the long-term sequelae of electrical injury is impaired by the necessity of retrospective methods and case studies that typically describe small cohorts. Main message There are 2 possible consequences of electrical injury: the person either survives or dies. For those who survive electrical injury, the immediate consequences are usually obvious and often require extensive medical intervention. The long-term sequelae of the electrical injury might be more subtle, pervasive, and less well defined, but can include neurologic, psychological, and physical symptoms. In the field of compensation medicine, determining causation and attributing outcome to an injury that might not result in objective clinical findings becomes a considerable challenge. Conclusion The appearance of these consequences of electrical injury might be substantially delayed, with onset 1 to 5 or more years after the electrical injury. This poses a problem for patients and health care workers, making it hard to ascribe symptoms to a remote injury when they might not arise until well after the incident event. PMID:24029506

  11. Long-term Variation of AGNs

    NASA Astrophysics Data System (ADS)

    Fan, J. H.; Xie, G. Z.; Adam, G.; Copin, Y.; Lin, R. G.; Bai, J. M.; Quin, Y. P.

    In this paper we will present the long-term variation in the optical and the infrared bands for some selected AGNs. 1. Some new optical data observed by us have been presented for BL Lacertae (1995-1996) and OJ 287 (1994-1995), and new infrared data are presented for OJ 287 (Nov=2E 1995), which corresponds to the second optical peak (Sillanpaa et al. 1996; Takalo et al. 1996) and during last outburst. 2. For objects with long term observations, the Jurkevich's method has been used to analyses the long-term variation period. It is interesting that the reported periods of AGNs are of the similar value of about 10 years: 3C 345 11.4 years (Webb et al. 1988), 3C 120 15 years (Belokon et al. 1987; Hagen-Thorn et al. 1997), ON 231 13.6 years (Liu et al. 1995), OJ 287 12 years (Sillanpaa et al. 1988; Kidger et al. 1992), PKS 0735+178 14 years (Fan et al. 1997), NGC 4151 15 years (Fan et al. 1998a), BL Lacertae 14.0 years (Fan et al. 1998b). Is the mechanism for the long-term variation the same for different AGNs? 3. The DCF method has been adopted to analysis the variation correlation in the optical and infrared bands for BL Lac object OJ 287, the results show that these two bands are strongly correlated, which suggest that the emission mechanism in the two bands is the same. 4. For the optical and infrared bands, the maximum variations are correlated.

  12. Long-term home hemodialysis in children

    PubMed Central

    Borra, Sonia; Kaye, Michael

    1971-01-01

    Experience with chronic hemodialysis as a definitive form of therapy is described for six children aged 11 to 15 years at the onset. Duration on dialysis in the home has been between one and 4½ years. All patients are alive and rehabilitated without serious complications. It is concluded that although transplantation is the most desirable form of treatment for children, long-term hemodialysis is an alternative acceptable second choice. ImagesFIG. 2 PMID:5150193

  13. Long-term consequences of anorexia nervosa.

    PubMed

    Meczekalski, Blazej; Podfigurna-Stopa, Agnieszka; Katulski, Krzysztof

    2013-07-01

    Anorexia nervosa (AN) is a psychiatric disorder that occurs mainly in female adolescents and young women. The obsessive fear of weight gain, critically limited food intake and neuroendocrine aberrations characteristic of AN have both short- and long-term consequences for the reproductive, cardiovascular, gastrointestinal and skeletal systems. Neuroendocrine changes include impairment of gonadotropin releasing-hormone (GnRH) pulsatile secretion and changes in neuropeptide activity at the hypothalamic level, which cause profound hypoestrogenism. AN is related to a decrease in bone mass density, which can lead to osteopenia and osteoporosis and a significant increase in fracture risk in later life. Rates of birth complications and low birth weight may be higher in women with previous AN. The condition is associated with fertility problems, unplanned pregnancies and generally negative attitudes to pregnancy. During pregnancy, women with the condition have higher rates of hyperemesis gravidarum, anaemia and obstetric complications, as well as impaired weight gain and compromised intrauterine foetal growth. It is reported that 80% of AN patients are affected by a cardiac complications such as sinus bradycardia, a prolonged QT interval on electrocardiography, arrythmias, myocardial mass modification and hypotension. A decrease in bone mineral density (BMD) is one of the most important medical consequences of AN. Reduced BMD may subsequently lead to a three- to seven-fold increased risk of spontaneous fractures. Untreated AN is associated with a significant increase in the risk of death. Better detection and sophisticated therapy should prevent the long-term consequences of this disorder. The aims of treatment are not only recovery but also prophylaxis and relief of the long-term effects of this disorder. Further investigations of the long-term disease risk are needed. PMID:23706279

  14. Titanium for long-term tritium storage

    SciTech Connect

    Heung, L.K.

    1994-12-01

    Due to the reduction of nuclear weapon stockpile, there will be an excess of tritium returned from the field. The excess tritium needs to be stored for future use, which might be several years away. A safe and cost effective means for long term storage of tritium is needed. Storing tritium in a solid metal tritide is preferred to storing tritium as a gas, because a metal tritide can store tritium in a compact form and the stored tritium will not be released until heat is applied to increase its temperature to several hundred degrees centigrade. Storing tritium as a tritide is safer and more cost effective than as a gas. Several candidate metal hydride materials have been evaluated for long term tritium storage. They include uranium, La-Ni-Al alloys, zirconium and titanium. The criteria used include material cost, radioactivity, stability to air, storage capacity, storage pressure, loading and unloading conditions, and helium retention. Titanium has the best combination of properties and is recommended for long term tritium storage.

  15. [Long-term survival after severe trauma].

    PubMed

    Mutschler, W; Mutschler, M; Graw, M; Lefering, R

    2016-07-01

    Long-term survival after severe trauma is rarely addressed in German trauma journals although knowledge of life expectancy and identification of factors contributing to increased mortality are important for lifetime care management, development of service models, and targeting health promotion and prevention interventions. As reliable data in Germany are lacking, we compiled data mainly from the USA and Australia to describe life expectancy, risk factors, and predictors of outcome in patients experiencing traumatic spinal cord injury, traumatic brain injury, and polytrauma. Two years after trauma, life expectancy in all three categories was significantly lower than that of the general population. It depends strongly on severity of disability, age, and gender and is quantifiable. Whereas improvements in medical care have led to a marked decline in short-term mortality, surprisingly long-term survival in severe trauma has not changed over the past 30 years. Therefore, there is need to intensify long-term trauma patient care and to find new strategies to limit primary damage. PMID:27342106

  16. Long-Term Environmental Research Programs - Evolving Capacity for Discovery

    NASA Astrophysics Data System (ADS)

    Swanson, F. J.

    2008-12-01

    Long-term forestry, watershed, and ecological research sites have become critical, productive nodes for environmental science research and in some cases for work in the social sciences and humanities. The Forest Service's century-old Experimental Forests and Ranges and the National Science Foundation's 28- year-old Long-Term Ecological Research program have been remarkably productive in both basic and applied sciences, including characterization of acid rain and old-growth ecosystems and development of forest, watershed, and range management systems for commercial and other land use objectives. A review of recent developments suggests steps to enhance the function of collections of long-term research sites as interactive science networks. The programs at these sites have evolved greatly, especially over the past few decades, as the questions addressed, disciplines engaged, and degree of science integration have grown. This is well displayed by small, experimental watershed studies, which first were used for applied hydrology studies then more fundamental biogeochemical studies and now examination of complex ecosystem processes; all capitalizing on the legacy of intensive studies and environmental monitoring spanning decades. In very modest ways these collections of initially independent sites have functioned increasingly as integrated research networks addressing inter-site questions by using common experimental designs, being part of a single experiment, and examining long-term data in a common analytical framework. The network aspects include data sharing via publicly-accessible data-harvester systems for climate and streamflow data. The layering of one research or environmental monitoring network upon another facilitates synergies. Changing climate and atmospheric chemistry highlight a need to use these networks as continental-scale observatory systems for assessing the impacts of environmental change on ecological services. To better capitalize on long-term

  17. Influence of Elevated Atmospheric Carbon Dioxide on Transcriptional Responses of Bradyrhizobium japonicum in the Soybean Rhizoplane

    PubMed Central

    Sugawara, Masayuki; Sadowsky, Michael J.

    2013-01-01

    Elevated atmospheric CO2 can influence the structure and function of rhizoplane and rhizosphere microorganisms by altering root growth and the quality and quantity of compounds released into the rhizoplane and rhizosphere via root exudation. In these studies we investigated the transcriptional responses of Bradyrhizobium japonicum cells growing in the rhizoplane of soybean plants exposed to elevated atmospheric CO2. The results of microarray analyses indicated that elevated atmospheric CO2 concentration indirectly influenced the expression of a large number of genes in Bradyrhizobium attached to soybean roots. In addition, relative to plants and bacteria grown under ambient CO2 growth conditions, genes involved in C1 metabolism, denitrification and FixK2-associated genes, including those involved in nitrogen fixation, microaerobic respiration, respiratory nitrite reductase, and heme biosynthesis, were significantly up-regulated under conditions of elevated CO2 in the rhizosphere. The expression profile of genes involved in lipochitooligosaccharide Nod factor biosynthesis and negative transcriptional regulators of nodulation genes, nolA and nodD2, were also influenced by plant growth under conditions of elevated CO2. Taken together, the results of these studies indicate that the growth of soybeans under conditions of elevated atmospheric CO2 influences gene expressions in B. japonicum in the soybean rhizoplane, resulting in changes to carbon/nitrogen metabolism, respiration, and nodulation efficiency. PMID:23666536

  18. Long-Term Photometric Monitoring of Two Redback Pulsar Systems

    NASA Astrophysics Data System (ADS)

    Torres, Rodrigo Alberto; Roberts, Mallory; Russell, Dave

    2016-06-01

    Redback systems consist of an eclipsing millisecond pulsar in a short period orbit (< 1 day) around a non-degenerate companion. These systems can potentially transition from their current state where they are ablating their companion to an accreting state. How such a transition can take place is poorly understood. Long-term monitoring of their optical orbital light-curves are important to answer questions about their evolution as well as to catch transitions between states. The orbital light curves can be used to infer the systems’ inclination angle, necessary to measure component masses, the effects of the pulsar heating on the atmosphere of the companion, and long term trends in the light curve may give some clue to the mechanism by which they transition. In this poster we present preliminary photometric light-curves of two binary, redback pulsar systems: PSR J2215+5135 and PSR J1628-3205. These data were taken in 2015 and 2016 with the 1m telescopes of the LCOGT observatory in several standard SDSS filter bands. We will compare the resulting light-curves with previous work on these systems to refine models of the light curves and to look for any long term trends in the optical emission such has been seen in the redback system PSR J2129-0429.

  19. Long-term variability of solar magnetic fields

    NASA Astrophysics Data System (ADS)

    Todd Hoeksema, J.; Scherrer, P. H.

    The solar magnetic field varies on all time scales. Recent analysis of 600 million year-old Australian varves shows terrestrial evidence for not only the familiar 22-year magnetic cycle, but variations with periods of 300-400 years as well. The Maunder minimum is but one of several long intervals showing atypical levels of solar activity. Recently a 151-day periodicity in flare activity has been found. Active regions, sunspots, ephemeral regions, and flares cover a broad range of shorter time scale variations in the solar magnetic field. Long-term variations can be interpreted in at least two ways. One outlook regards the large-scale and long-term variations of the photospheric field as more-or-less direct guides to the organization of the solar field as it evolves through a solar cycle. The slowly varying field reveals the fundamental interior structure of the Sun. An alternative view interprets the surface manifestation of the magnetic field primarily as the result of the convective motions in the solar atmosphere. The evolving distribution of photospheric flux depends upon the locations of emerging flux and the subsequent motions and interactions of the fields in the moving plasma. Information about the interior field comes largely from analysis of emerging flux. We discuss interpretation of the phenomenology of the long-term variability in the context of these contrasting views.

  20. Two decades of regular observations of (CO{sub 2})-C-14 and (CO{sub 2})-C-13 content in atmospheric carbon dioxide in central Europe: Long-term changes of regional anthropogenic fossil CO{sub 2} emissions

    SciTech Connect

    Kuc, T.; Rozanski, K.; Zimnoch, M.; Necki, J.; Chmura, L.; Jelen, D.

    2007-07-01

    Time series are presented of radiocarbon and C-13 contents in atmospheric carbon dioxide over eastern Europe (southern Poland), covering the periods 1983-1994 and 2000-2004. The carbon isotope composition was measured in biweekly composite samples of atmospheric CO{sub 2}, collected about 20 m above the local ground level. The data for 2 observational sites are presented: I) city of Krakow (50{sup o} 04'N, 19{sup o} 55'E; 220 m asl; for 1983-1994 and 2000-2004); and ii) Kasprowy Wierch, Tatra Mountains (49{sup o} 14'N, 19{sup o} 56'E; 1989 m asl; for 2000-2004). The latter site is considered a regional reference station, relatively free of anthropogenic influences. During the period 1983-1994, observations in the Krakow area revealed a gradual decrease of C-14 content with a broad minimum around 1991 and a small increase by about 10 parts per thousand in the subsequent years. {delta}C-13 also changes with time, showing a decreasing trend from approximately -9.6 parts per thousand in 1983, with a slope of -0.02 parts per thousand/yr. The observed trends for both isotopes coincide well with a substantial reduction of coal consumption in Poland and partial replacement of coal by natural gas, especially in urban regions. After 2000, the {delta}C-13 slightly increases, reaching a mean value of -10 parts per thousand in 2004, while {delta}C-14 is below the reference level by similar to 3.5 parts per thousand. Observations at Kasprowy Wierch (regional reference station) also reflect a diminishing input of fossil carbon into the regional atmosphere. The fossil component in atmospheric CO{sub 2}, calculated with the aid of C-14 data available for the 2 study periods, shows a reduction of anthropogenic input by a factor of 2, which is confirmed by annual statistics of coal consumption.

  1. Widespread elevated atmospheric SF 6 mixing ratios in the Northeastern United States: Implications for groundwater dating

    NASA Astrophysics Data System (ADS)

    Santella, Nicholas; Ho, David T.; Schlosser, Peter; Stute, Martin

    2008-01-01

    SummarySF 6 is a promising transient tracer for groundwater dating, but elevated levels of atmospheric SF 6 may limit application of this dating method in urban areas. To determine the magnitude of this limitation within the United States (US), this study derives average atmospheric SF 6 mixing ratios from soil air measurements from five major urban areas. All surveyed sites showed SF 6 elevated above Northern Hemisphere clean air levels. In many cases, SF 6 mixing ratios were highest within large cities, but significantly elevated levels persisted hundreds of kilometers beyond the urban centers. Estimated SF 6 emissions from New York city were anomalously large, resulting in average levels over 200% above remote atmosphere values. Emissions from other urban areas included in this study appear to be typical for large cities in the US and maximum observed elevations of SF 6, in these areas, were in the range of 50-100%. These findings imply that caution is needed in choosing an atmospheric input function when using SF 6 as a transient tracer within or near urbanized regions. Within the Northeast US, the assumption of remote atmospheric SF 6 may lead to significant errors in estimation of groundwater ages, especially in the case of an expected future flattening of the atmospheric mixing ratio curve.

  2. Long-term biogeochemical impacts of liming the ocean

    NASA Astrophysics Data System (ADS)

    Ilyina, T.; Wolf-Gladrow, D.; Munhoven, G.; Heinze, C.

    2011-12-01

    Fossil fuel CO2 emissions result in large-scale long-term perturbations in seawater chemistry. Oceans take up atmospheric CO2, and several geo-engineering approaches have been suggested to mitigate impacts of CO2 emissions and resulting ocean acidification that are based on this property. One of them is to enhance weathering processes to remove atmospheric CO2. This method involves dissolving rocks (i.e. limestone) or adding strong bases (i.e. calcium hydroxide) in the upper ocean and is termed as liming the oceans. The net effect of this approach is to increase ocean alkalinity, thereby increasing the oceanic capacity to store anthropogenic CO2. Another effect of adding alkalinity would be to drive seawater to higher pH values and thus counteract the ongoing ocean acidification. However, whereas adding bases only alter alkalinity of seawater, dissolution of carbonates perturb both, alkalinity and dissolved inorganic carbon budgets. Thus, on longer time scales, these two methods will likely have different biogeochemical effects in the ocean. Here we test enduring implications of the two approaches for marine carbon cycle using the global ocean biogeochemical model HAMOCC. In our model scenarios we add alkalinity in the amounts proportional to fossil fuel emissions. We compare the long-term effectiveness of the two geo-engineering approaches to decrease atmospheric CO2.

  3. The long-term prediction of artificial satellite orbits

    NASA Technical Reports Server (NTRS)

    Cefola, P. J.; Long, A. C.; Holloway, G., Jr.

    1974-01-01

    Survey of averaging and multirevolution methods for long-term orbit prediction. A technical approach with the following features is recommended: (1) averaged variation-of-parameter equations, (2) analytical expressions for oblateness and third-body effects, (3) definite integrals for atmospheric drag and lunar effects (for long-period orbits), (4) nonsingular equinoctial element formulation, (5) multistep numerical integration processes, and (6) precise osculating-to-mean element transformation. Several orbital predictions illustrate the contribution of this technical approach to overall accuracy and efficiency. Future development of the analytical averaging method in nonsingular coordinates by automated manipulation of literal series is discussed.

  4. The effects of long-term sleep deprivation on the long-term potentiation in the dentate gyrus and brain oxidation status in rats.

    PubMed

    Süer, Cem; Dolu, Nazan; Artis, A Seda; Sahin, Leyla; Yilmaz, Alpaslan; Cetin, Aysun

    2011-05-01

    Some evidence suggests that sleep deprivation might impair synaptic plasticity and produce oxidative stress in the hippocampus. However it is not clear whether impairment of long-term potentiation depends on the oxidative stress evoked by sleep deprivation protocol. In this study we aimed to investigate the effects of a 21-day sleep deprivation period on long-term plasticity taking into account the stressful effect of sleep deprivation. Sleep deprivation was carried out using the multiple platforms method on adult male Wistar rats. Long-term potentiation was studied in the medial perforant pathway-dentate gyrus synapses. Elevated T test was applied, and blood corticosterone levels were measured. Lipid peroxidation products in whole brain and hippocampus were determined. No significant difference was found between the sleep deprived, pedestal and cage control groups at the end of the 21-day period when corticosterone levels were compared. The results of the elevated T test indicated that sleep deprivation did not change the anxiety-like behavior of the animals. When compared with cage or pedestal control groups, sleep deprived rats displayed elevated malondialdehyde levels, and decreased superoxide dismutase and glutathione peroxidase activities together with impaired long-term potentiation maintenance. It can be argued that 21-day SD may impair the maintenance of long-term potentiation evoked in the dentate gyrus, and the balance between oxidant and antioxidant defenses of the hippocampus. PMID:21256900

  5. Martian particle size based on thermal inertia corrected for elevation-dependent atmospheric properties

    NASA Technical Reports Server (NTRS)

    Bridges, N. T.

    1993-01-01

    Thermal inertia is commonly used to derive physical properties of the Martian surface. If the surface is composed of loosely consolidated grains, then the thermal conductivity derived from the inertia can theoretically be used to compute the particle size. However, one persistent difficulty associated with the interpretation of thermal inertia and the derivation of particle size from it has been the degree to which atmospheric properties affect both the radiation balance at the surface and the gas conductivity. These factors vary with atmospheric pressure so that derived thermal inertias and particle sizes are a function of elevation. By utilizing currently available thermal models and laboratory information, a fine component thermal inertia map was convolved with digital topography to produce particle size maps of the Martian surface corrected for these elevation-dependent effects. Such an approach is especially applicable for the highest elevations on Mars, where atmospheric back radiation and gas conductivity are low.

  6. [Plant responses to elevated atmospheric carbon dioxide and transmission to other trophic levels]. Final report

    SciTech Connect

    Lincoln, D.E.

    1995-10-01

    This program investigated how host plant responses to elevated atmospheric carbon dioxide may be transmitted to other trophic levels, especially leaf eating insects, and alter consumption of leaves and impare their function. Study results included the following findings: increased carbon dioxide to plants alters feeding by insect herbivores; leaves produced under higher carbon conditions contain proportionally less nitrogen; insect herbivores may have decreased reproduction under elevated carbon dioxide.

  7. Long-term trends in dissolved iron and DOC concentration linked to nitrate depletion in riparian soils

    NASA Astrophysics Data System (ADS)

    Musolff, Andreas; Selle, Benny; Fleckenstein, Jan H.; Oosterwoud, Marieke R.; Tittel, Jörg

    2016-04-01

    The instream concentrations of dissolved organic carbon (DOC) are rising in many catchments of the northern hemisphere. Elevated concentrations of DOC, mainly in the form of colored humic components, increase efforts and costs of drinking water purification. In this study, we evaluated a long-term dataset of 110 catchments draining into German drinking water reservoirs in order to assess sources of DOC and drivers of a potential long-term change. The average DOC concentrations across the wide range of different catchments were found to be well explained by the catchment's topographic wetness index. Higher wetness indices were connected to higher average DOC concentrations, which implies that catchments with shallow topography and pronounced riparian wetlands mobilize more DOC. Overall, 37% of the investigated catchments showed a significant long-term increase in DOC concentrations, while 22% exhibited significant negative trends. Moreover, we found that increasing trends in DOC were positively correlated to trends in dissolved iron concentrations at pH≤6 due to remobilization of DOC previously sorbed to iron minerals. Both, increasing trends in DOC and dissolve iron were found to be connected to decreasing trends and low concentrations of nitrate (below ~6 mg/L). This was especially observed in forested catchments where atmospheric N-depositions were the major source for nitrate availability. In these catchments, we also found long-term increases of phosphate concentrations. Therefore, we argue that dissolved iron, DOC and phosphate were jointly released under iron-reducing conditions when nitrate as a competing electron acceptor was too low in concentrations to prevent the microbial iron reduction. In contrast, we could not explain the observed increasing trends in DOC, iron and phosphate concentrations by the long-term trends of pH, sulfate or precipitation. Altogether this study gives strong evidence that both, source and long-term increases in DOC are

  8. Long-term EARLINET dust observations

    NASA Astrophysics Data System (ADS)

    Mona, Lucia; Amiridis, Vassilis; Amodeo, Aldo; Binietoglou, Ioannis; D'Amico, Giuseppe; Schwarz, Anja; Papagiannopoulos, Nikolaos; Papayannis, Alexandros; Sicard, Michael; Comeron, Adolfo; Pappalardo, Gelsomina

    2015-04-01

    Systematic observations of Saharan dust events over Europe are performed from May 2000 by EARLINET, the European Aerosol Research LIdar NETwork. EARLINET is a coordinated network of stations that make use of advanced lidar methods for the vertical profiling of aerosols. The backbone of EARLINET network is a common schedule for performing the measurements and the quality assurance of instruments/data. Particular attention is paid to monitoring the Saharan dust intrusions over the European continent. The geographical distribution of the EARLINET stations is particularly appealing for the dust observation, with stations located all around the Mediterranean and in the center of the Mediterranean (Italian stations) where dust intrusions are frequent, and with several stations in the central Europe where dust penetrates occasionally. All aerosol backscatter and extinction profiles related to observations collected during these alerts are grouped in the devoted "Saharan dust" category of the EARLINET database. This category consists of about 4700 files (as of December 2013). Case studies involving several stations around Europe selected from this long-term database have been provided the opportunity to investigate dust modification processes during transport over the continent. More important, the long term EARLINET dust monitoring allows the investigation of the horizontal and vertical extent of dust outbreaks over Europe and the climatological analysis of dust optical intensive and extensive properties at continental scale. This long-term database is also a unique tool for a systematic comparison with dust model outputs and satellite-derived dust products. Because of the relevance for both dust modeling and satellite retrievals improvement, results about desert dust layers extensive properties as a function of season and source regions are investigated and will be presented at the conference. First comparisons with models outputs and CALIPSO dust products will be

  9. Timber beams subjected to long - term loading

    NASA Astrophysics Data System (ADS)

    Sógel, K.

    2010-09-01

    Wood is a significant structural material, which is often used for timber bearing structures. Elements of timber structures must especially satisfy safety requirements, which are expressed by the ultimate limit states in the established standards. The structure must also satisfy the serviceability limit states. Local and global deformations make it impossible for the structure to serve the purpose it was designed for. It is important to take the deflections and their possible increase into account in the design to provide a structure which can be used during the whole period of service. Based on earlier examinations, it is known that a timber element over the course of long-term loading shows creep behavior. The structure of wood is able to adapt to the conditions of the surrounding environment. The properties of wood are especially affected by the relative humidity of the air and then by the type, intensity and duration of the loading. The most important factors affecting the serviceability of timber structures are volume changes caused by humidity and additional deflections caused by the effects of long-term loading. These phenomena emphasize the importance of serviceability limit states for timber structures. The paper deals with a long-term experimental investigation of timber girders that are currently often used. The aim was to obtain the deflection curves and mark the time dependence and the final deflections. The paper will also define the approximations for simulating the time-dependent deflections and obtain the creep coefficients for calculating the final deflections of the girders investigated.

  10. [Long-term treatment with amiodarone].

    PubMed

    Baedeker, W; Goedel-Meinen, L; Schmidt, G; Hofmann, M; Barthel, P; Blömer, H

    1991-02-01

    The aim of this study was to investigate the efficacy and the side effects of a long-term treatment with amiodarone. We analyzed the data of 41 patients in whom amiodarone therapy had been initiated between 1974 and 1984. Twenty-one patients had dilative cardiomyopathy, 14 patients had chronic myocardial infarction, four patients suffered from WPW syndrome with intermittent atrial fibrillation, one patient had aortic valve surgery, whereas in one patient there was no clinical evidence of a heart disease. All patients had salvos of ventricular extrasystoles, ventricular tachycardia or documented intermittent ventricular fibrillation. There have been seven drop-outs up to the present time. In each patient, the lowest antiarrhythmically effective dose was applied, which was generally higher in patients with low ejection fraction. Effective treatment of the ventricular tachycardia was achieved in 55-92% of patients and did not depend on the duration of treatment. In 10 patients in whom amiodarone therapy had to be stopped for various reasons. Sudden cardiac death was slightly more frequent than in the 24 patients treated with amiodarone, though the difference was not significant. In cases with a history of syncope the prognosis was poor, even with amiodarone therapy. Due to side effects, a dosage reduction or discontinuation of amiodarone treatment became necessary in 14 patients. Amiodarone proved to be an effective drug also for the long-term treatment of ventricular tachycardia, and possibly for the prevention of sudden cardiac death. With the exception of blue skin color, there was no accumulation of side effects, even during long-term treatment of several years. PMID:1711739

  11. Long Term Archiving and CCSDS Standards

    NASA Astrophysics Data System (ADS)

    Boucon, Danièle

    This article presents some conceptual and implementation CCSDS -Consultative Committee for Space Data Systemsstandards for long term archiving. It focuses on the most recent one, the Producer Archive Interface Specification (PAIS) standard. This standard, currently available as a draft on the CCSDS web site, will be published by the beginning of 2014. It will enable the Producer to share with the Archive a sufficiently precise and unambiguous formal definition of the Digital Objects to be produced and transferred, by means of a model. It will also enable a precise definition of the packaging of these objects in the form of Submission Information Packages (SIPs), including the order in which they should be transferred.

  12. Long-Term Wind Power Variability

    SciTech Connect

    Wan, Y. H.

    2012-01-01

    The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.

  13. Long-term outcomes in multiple gestations.

    PubMed

    Rand, Larry; Eddleman, Keith A; Stone, Joanne

    2005-06-01

    Children born from a multiple gestation are at increased risk for cerebral palsy, learning disability, and language and neurobehavioral deficits. With the increased incidence of multiple pregnancies and use of assisted reproductive technology (ART), these issues are more commonly affecting parents. Long-term outcomes are a critical part of preconceptual and early pregnancy counseling for parents faced with a multiple gestation or considering ART, and the provider should be well versed on issues surrounding zygosity, gestational age, higher-order multiples, and the effects of options such as multifetal pregnancy reduction. PMID:15922795

  14. Performance considerations in long-term spaceflight

    NASA Technical Reports Server (NTRS)

    Akins, F. R.

    1979-01-01

    Maintenance of skilled performance during extended space flight is of critical importance to both the health and safety of crew members and to the overall success of mission goals. An examination of long term effects and performance requirements is therefore a factor of immense importance to the planning of future missions. Factors that were investigated include: definition of performance categories to be investigated; methods for assessing and predicting performance levels; in-flight factors which can affect performance; and factors pertinent to the maintenance of skilled performance.

  15. Human Behaviour in Long-Term Missions

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session WP1, the discussion focuses on the following topics: Psychological Support for International Space Station Mission; Psycho-social Training for Man in Space; Study of the Physiological Adaptation of the Crew During A 135-Day Space Simulation; Interpersonal Relationships in Space Simulation, The Long-Term Bed Rest in Head-Down Tilt Position; Psychological Adaptation in Groups of Varying Sizes and Environments; Deviance Among Expeditioners, Defining the Off-Nominal Act in Space and Polar Field Analogs; Getting Effective Sleep in the Space-Station Environment; Human Sleep and Circadian Rhythms are Altered During Spaceflight; and Methodological Approach to Study of Cosmonauts Errors and Its Instrumental Support.

  16. 47 CFR 54.303 - Long term support.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Long term support. 54.303 Section 54.303... SERVICE Universal Service Support for High Cost Areas § 54.303 Long term support. (a) Beginning January 1... shall receive Long Term Support. Beginning July 1, 2004, no carrier shall receive Long Term Support....

  17. 47 CFR 54.303 - Long term support.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Long term support. 54.303 Section 54.303... SERVICE Universal Service Support for High Cost Areas § 54.303 Long term support. (a) Beginning January 1... shall receive Long Term Support. Beginning July 1, 2004, no carrier shall receive Long Term Support....

  18. Long-term weather predictability: Ural case study

    NASA Astrophysics Data System (ADS)

    Kubyshen, Alexander; Shopin, Sergey

    2016-04-01

    proved the efficiency of the method for forecasting the following meteorological parameters: ­- air temperature (minimum, maximum, daily mean, diurnal variation, last spring and first autumn freeze); - periods of winds with speeds of >5m/s and the maximal expected wind speed; - precipitation periods and amount of precipitations; -­ relative humidity; - atmospheric pressure. Atmospheric events (thunderstorms, fog) and hydrometeors also occupy the appropriate positions at the sequence diagrams that provides a possibility of long-term forecasting also for these events. Accuracy of forecasts was tested in 2006-2009 years. The difference between the forecasted monthly mean temperature and actual values was <0.5°C in 40.9% of cases, between 0.5°C and 1°C in 18.2% of cases, between 1°C and 1.5°C in 18.2% of cases, <2°C in 86% of cases. The RAMES method provides the toolkit to successfully forecast the weather conditions in advance of several years. 1. A.F. Kubyshen, "RAMES method: revealing the periodicity of meteorological processes and it usage for long-term forecast [Metodika «RAMES»: vyjavlenie periodichnosti meteorologicheskih processov i ee ispol'zovanie dlja dolgosrochnogo prognozirovanija]", in A.E. Fedorov (ed.), Sistema «Planeta Zemlja»: 200 let so dnja rozhdenija Izmaila Ivanovicha Sreznevskogo. 100 let so dnja izdanija ego slovarja drevnerusskogo jazyka. LENAND. Moscow. pp. 305-311. (In Russian)

  19. The effect of elevated atmospheric CO2 concentration on gross nitrogen and carbon dynamics in a permanent grassland: A field pulse-labeling study

    NASA Astrophysics Data System (ADS)

    Moser, Gerald; Gorenflo, André; Keidel, Lisa; Brenzinger, Kristof; Elias, Dafydd; McNamara, Niall; Maček, Irena; Vodnik, Dominik; Braker, Gesche; Schimmelpfennig, Sonja; Gerstner, Judith; Müller, Christoph

    2014-05-01

    To predict ecosystem reactions to elevated atmospheric CO2 (eCO2) it is essential to understand the interactions between plant carbon input, microbial community composition and activity and associated nutrient dynamics. Long-term observations (> 14 years) within the Giessen Free Air Carbon dioxide Enrichment (Giessen FACE) study on permanent grassland showed next to an enhanced biomass production an unexpected strong positive feedback effect on ecosystem respiration and nitrous oxide (N2O) production. The overall goal of this study is to understand the long-term effects of eCO2 and carbon input on microbial community composition and activity as well as the associated nitrogen dynamics, N2O production and plant N uptake in the Giessen FACE study on permanent grassland. A combination of 13CO2 pulse labelling with 15N tracing of 15NH4+ and 15NO3- was carried out in situ. Different fractions of soil organic matter (recalcitrant, labile SOM) and the various mineral N pools in the soil (NH4+, NO3-), gross N transformation rates, pool size dependent N2O and N2 emissions as well as N species dependent plant N uptake rates and the origin of the CO2 respiration have been quantified. Microbial analyses include exploring changes in the composition of microbial communities involved in the turnover of NH4+, NO3-, N2O and N2, i.e. ammonia oxidizing, denitrifying, and microbial communities involved in dissimilatory nitrate reduction to ammonia (DNRA). mRNA based analyses will be employed to comparably evaluate the long-term effects of eCO2 on the structure and abundance of these communities, while transcripts of these genes will be used to target the fractions of the communities which actively contribute to N transformations. We quantified the contribution of mycorrhizae on N2O emissions and observed the phenological development of the mycorrhizae after the labeling.

  20. Effects of long-term and short-term warming on VOC emissions from a Subarctic heath

    NASA Astrophysics Data System (ADS)

    Valolahti, Hanna; Faubert, Patrick; Michelsen, Anders; Rinnan, Riikka

    2013-04-01

    It is predicted that the temperature increase during the next 100 years will be highest in the high latitudes. Temperature is also the main factor affecting the volatile organic compound (VOC) emissions by plants. In the Subarctic, the VOC emissions appear to be even more sensitive to temperature changes than in temperate systems, probably because the plant species are adapted to colder climate. The arctic ecosystems are very sensitive to any disturbances, and therefore it is important to study climate change effects and predict future responses in these areas. Long-term climate change experiment with elevated temperature and litter addition treatments has been running on a subarctic heath in Abisko, North Sweden since 1999. Five treatments (1. unmanipulated control, 2. long-term warming, 3. short-term warming, 4. litter addition and 5. litter addition + warming) are replicated in six blocks. In 2010, eight vegetation-soil-chamber-based VOC collection campaigns were made. VOCs were collected into adsorbent cartridges, which were analyzed by thermal desorption and gas chromatography-mass spectrometry. Point quadrant analysis was used to investigate the species composition in the different treatments, and the vegetation data was used as an explaining factor for the different VOC emission profiles between treatments. Elevated temperature significantly increased the total VOC emission from the subarctic heath. Most significant effects were found for the emissions of isoprene and sesquiterpenes. The short-term and long-term temperature treatments differed for the emissions of total terpenoids. According to these results, elevated temperature has both long- and short term effects on VOC-emissions. In the short term, direct temperature effect increases VOC-emissions. In the long term, indirect effects via vegetation changes dominate. After the release into the atmosphere, the lifetime of VOCs is from seconds to days. They participate in secondary organic aerosol formation

  1. Sleep facilitates long-term face adaptation.

    PubMed

    Ditye, Thomas; Javadi, Amir Homayoun; Carbon, Claus-Christian; Walsh, Vincent

    2013-10-22

    Adaptation is an automatic neural mechanism supporting the optimization of visual processing on the basis of previous experiences. While the short-term effects of adaptation on behaviour and physiology have been studied extensively, perceptual long-term changes associated with adaptation are still poorly understood. Here, we show that the integration of adaptation-dependent long-term shifts in neural function is facilitated by sleep. Perceptual shifts induced by adaptation to a distorted image of a famous person were larger in a group of participants who had slept (experiment 1) or merely napped for 90 min (experiment 2) during the interval between adaptation and test compared with controls who stayed awake. Participants' individual rapid eye movement sleep duration predicted the size of post-sleep behavioural adaptation effects. Our data suggest that sleep prevented decay of adaptation in a way that is qualitatively different from the effects of reduced visual interference known as 'storage'. In the light of the well-established link between sleep and memory consolidation, our findings link the perceptual mechanisms of sensory adaptation--which are usually not considered to play a relevant role in mnemonic processes--with learning and memory, and at the same time reveal a new function of sleep in cognition. PMID:23986109

  2. Long term perfusion system supporting adipogenesis

    PubMed Central

    Abbott, Rosalyn D.; Raja, Waseem K.; Wang, Rebecca Y.; Stinson, Jordan A.; Glettig, Dean L.; Burke, Kelly A.; Kaplan, David L.

    2015-01-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogensis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight. PMID:25843606

  3. Long Term Changes in the Polar Vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2016-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented. The unusual meteorological conditions of the 2015 south polar vortex and the 2010/11 and 2015/16 north polar vortices will be compared to other recent years.

  4. Long-Term Care Policy: Singapore's Experience.

    PubMed

    Chin, Chee Wei Winston; Phua, Kai-Hong

    2016-01-01

    Singapore, like many developed countries, is facing the challenge of a rapidly aging population and the increasing need to provide long-term care (LTC) services for elderly in the community. The Singapore government's philosophy on care for the elderly is that the family should be the first line of support, and it has relied on voluntary welfare organizations (VWOs) or charities for the bulk of LTC service provision. For LTC financing, it has emphasized the principles of co-payment and targeting of state support to the low-income population through means-tested government subsidies. It has also instituted ElderShield, a national severe disability insurance scheme. This paper discusses some of the challenges facing LTC policy in Singapore, particularly the presence of perverse financial incentives for hospitalization, the pitfalls of over-reliance on VWOs, and the challenges facing informal family caregivers. It discusses the role of private LTC insurance in LTC financing, bearing in mind demand- and supply-side failures that have plagued the private LTC insurance market. It suggests the need for more standardized needs assessment and portable LTC benefits, with reference to the Japanese Long-Term Care Insurance program, and also discusses the need to provide more support to informal family caregivers. PMID:26808468

  5. Long term changes in the polar vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2015-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented.

  6. Long-term intracranial pressure monitoring.

    PubMed

    de Jong, D A; Maas, A I; den Ouden, A H; de Lange, S A

    Continuous or intermittent measurement of intracranial pressure (ICP) is important in patients at risk for raised ICP. Indications exist for short- and long-term measurements. The various methods used for short-term monitoring are discussed with their relative advantages and disadvantages. For long-term measurements of ICP use of a completely implantable telemetric epidural pressure transducer is indicated. No such device is commercially available. We have developed an inexpensive passive telemetric transducer for this purpose. Results obtained up till now have demonstrated its reliability for measurements of two to three months duration. The life span of the device is limited by degrading of the epoxy utilized for sealing of the titanium pressure sensing part to the radiolucent ceramic cap of the transducer, causing leakage of water into the transducer and false low measurements. Because of these problems new hermetic sealing techniques were tested. Both active metal brazing and glass bonding yielded good results and hermetic sealing could be obtained. The metal to ceramic bonding presented is generally applicable within the design of implants. Besides the technical progress reported, the experience with clinical use in 12 patients is presented. PMID:6674738

  7. Long-term decline of the Amazon carbon sink.

    PubMed

    Brienen, R J W; Phillips, O L; Feldpausch, T R; Gloor, E; Baker, T R; Lloyd, J; Lopez-Gonzalez, G; Monteagudo-Mendoza, A; Malhi, Y; Lewis, S L; Vásquez Martinez, R; Alexiades, M; Álvarez Dávila, E; Alvarez-Loayza, P; Andrade, A; Aragão, L E O C; Araujo-Murakami, A; Arets, E J M M; Arroyo, L; Aymard C, G A; Bánki, O S; Baraloto, C; Barroso, J; Bonal, D; Boot, R G A; Camargo, J L C; Castilho, C V; Chama, V; Chao, K J; Chave, J; Comiskey, J A; Cornejo Valverde, F; da Costa, L; de Oliveira, E A; Di Fiore, A; Erwin, T L; Fauset, S; Forsthofer, M; Galbraith, D R; Grahame, E S; Groot, N; Hérault, B; Higuchi, N; Honorio Coronado, E N; Keeling, H; Killeen, T J; Laurance, W F; Laurance, S; Licona, J; Magnussen, W E; Marimon, B S; Marimon-Junior, B H; Mendoza, C; Neill, D A; Nogueira, E M; Núñez, P; Pallqui Camacho, N C; Parada, A; Pardo-Molina, G; Peacock, J; Peña-Claros, M; Pickavance, G C; Pitman, N C A; Poorter, L; Prieto, A; Quesada, C A; Ramírez, F; Ramírez-Angulo, H; Restrepo, Z; Roopsind, A; Rudas, A; Salomão, R P; Schwarz, M; Silva, N; Silva-Espejo, J E; Silveira, M; Stropp, J; Talbot, J; ter Steege, H; Teran-Aguilar, J; Terborgh, J; Thomas-Caesar, R; Toledo, M; Torello-Raventos, M; Umetsu, R K; van der Heijden, G M F; van der Hout, P; Guimarães Vieira, I C; Vieira, S A; Vilanova, E; Vos, V A; Zagt, R J

    2015-03-19

    Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models. PMID:25788097

  8. Long-term decline of the Amazon carbon sink

    NASA Astrophysics Data System (ADS)

    Brienen, R. J. W.; Phillips, O. L.; Feldpausch, T. R.; Gloor, E.; Baker, T. R.; Lloyd, J.; Lopez-Gonzalez, G.; Monteagudo-Mendoza, A.; Malhi, Y.; Lewis, S. L.; Vásquez Martinez, R.; Alexiades, M.; Álvarez Dávila, E.; Alvarez-Loayza, P.; Andrade, A.; Aragão, L. E. O. C.; Araujo-Murakami, A.; Arets, E. J. M. M.; Arroyo, L.; Aymard C., G. A.; Bánki, O. S.; Baraloto, C.; Barroso, J.; Bonal, D.; Boot, R. G. A.; Camargo, J. L. C.; Castilho, C. V.; Chama, V.; Chao, K. J.; Chave, J.; Comiskey, J. A.; Cornejo Valverde, F.; da Costa, L.; de Oliveira, E. A.; di Fiore, A.; Erwin, T. L.; Fauset, S.; Forsthofer, M.; Galbraith, D. R.; Grahame, E. S.; Groot, N.; Hérault, B.; Higuchi, N.; Honorio Coronado, E. N.; Keeling, H.; Killeen, T. J.; Laurance, W. F.; Laurance, S.; Licona, J.; Magnussen, W. E.; Marimon, B. S.; Marimon-Junior, B. H.; Mendoza, C.; Neill, D. A.; Nogueira, E. M.; Núñez, P.; Pallqui Camacho, N. C.; Parada, A.; Pardo-Molina, G.; Peacock, J.; Peña-Claros, M.; Pickavance, G. C.; Pitman, N. C. A.; Poorter, L.; Prieto, A.; Quesada, C. A.; Ramírez, F.; Ramírez-Angulo, H.; Restrepo, Z.; Roopsind, A.; Rudas, A.; Salomão, R. P.; Schwarz, M.; Silva, N.; Silva-Espejo, J. E.; Silveira, M.; Stropp, J.; Talbot, J.; Ter Steege, H.; Teran-Aguilar, J.; Terborgh, J.; Thomas-Caesar, R.; Toledo, M.; Torello-Raventos, M.; Umetsu, R. K.; van der Heijden, G. M. F.; van der Hout, P.; Guimarães Vieira, I. C.; Vieira, S. A.; Vilanova, E.; Vos, V. A.; Zagt, R. J.

    2015-03-01

    Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.

  9. Using Tree Rings, CO2 Fluxes, and Long-Term Measurements to Understand Carbon Dynamics in an Alaskan Boreal Forest

    NASA Astrophysics Data System (ADS)

    Bond-Lamberty, B. P.; Anderson, C.; Crump, A.; Stegen, J.

    2015-12-01

    Decadal and centennial processes are usually poorly constrained by data, but many opportunities exist to combine disparate data sources such as tree rings, greenhouse gas fluxes from the soil to atmosphere, and long-term tree inventories. At high northern latitudes, permafrost (and its current degradation across large scales) is presumed to exert a strong control on long-term ecosystem carbon uptake and storage. We integrate a variety of data from both Canada and Alaska, focusing on two years of observations across a permafrost gradient in a black spruce Alaskan watershed (the Caribou/Poker Creek Research Watershed ~50 km northeast of Fairbanks, AK, USA). Permafrost depth changes were strongly associated with changes in vegetation and leaf morphology, as well as soil greenhouse fluxes (0.1-2.0 μmol/m2/s, with strong spatial dependencies) and aboveground net primary production (60-550 gC/m2/yr). We use tree-ring data covering the last century to examine how tree response to climate variability changes with elevation and permafrost depth, both along small-scale transects and across the entire 104 km2 watershed. A weakness is that these results are from a single site and point in successional time; we quantify potential variability in this area using 16 years of observations from a Canadian boreal chronosequence. We emphasize that both short and long term observations and experiments, using multiple approaches, are necessary to constrain ecosystem carbon uptake and storage.

  10. The Effects of Long Term Nitrogen Fertilization on Soil Respiration in Rocky Mountain National Park

    NASA Astrophysics Data System (ADS)

    Allen, J.; Denning, S.; Baron, J.

    2015-12-01

    Anthropogenic activities contribute to increased levels of nitrogen deposition and elevated CO2 concentrations in terrestrial ecosystems. The role that soils play in biogeochemical cycles is an important area of uncertainty in ecosystem ecology. One of the main reasons for this uncertainty is that we have limited understanding of belowground microbial activity and how this activity is linked to soil processes. In particular, elevated CO2 may influence soil nitrogen processes that regulate nitrogen availability to plants. Warming and nitrogen fertilization may both contribute to loss of stored carbon from mountain ecosystems, because they contribute to microbial decomposition of organic matter. To study the effects of long-term nitrogen fertilization on soil respiration, we analyzed results from a 25-year field experiment in Rocky Mountain National Park. Field treatments are in old growth Engelmann spruce forests. Soil respiration responses to the effects of nitrogen fertilization on soil carbon cycling, via respiration, were investigated during the 2013 growing season. Soil moisture, temperature, and respiration rates were measured in six 30 x 30 m plots, of the six plots three are fertilized with 25 kg N ha-1 yr-1 as ammonium nitrate (NH4NO3) pellets and three receives ambient atmospheric nitrogen deposition (1-6 kg N/ha/yr) in Rocky Mountain National Park. We found that respirations rates in the fertilized plots were not significantly higher than respiration rates in the unfertilized plots. We speculate that acclimation to long-term fertilization and relatively high levels of nitrogen deposition in the control plots both contribute to the insensitivity of soil respiration to fertilization at this site.

  11. Thermospheric hydrogen - The long-term solar influence

    NASA Technical Reports Server (NTRS)

    Breig, E. L.; Sanatani, S.; Hanson, W. B.

    1985-01-01

    Atmospheric Explorer C and E satellite data are employed for a long-term analysis of the behavior of thermospheric hydrogen with respect to the 11 yr solar cycle. The data covered the period 1974-79 (increasing solar activity) and comprised in situ ionospheric (F region) and neutral atmospheric data. The data were analyzed statistically to characterize low latitude hydrogen behavior, e.g., the diurnal variation and mean concentration over the 5 yr data sampling period. Both the mean and daily maximum/minimum ratio (DMMR) varied with the solar F index. The escaping flux of H ions became a contant around 1000 K. Increasing thermospheric temperatures lowered the DMMR value. However, the DMMR values calculated were consistently large enough to require inclusion of neutral winds and/or diurnal variations in charge exchange fluxes moving in and out of the plasmasphere in any model for thermospheric hydrogen behavior.

  12. Implications of elevated atmospheric CO2 on plant growth and water relations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Empirical records provide incontestable evidence for the global rise in CO2 concentration in the earth’s atmosphere. Plant growth can be stimulated by elevation of CO2; photosynthesis increases and economic yield is often enhanced. The application of more CO2 can result in less water use. Competitio...

  13. Biomass and toxicity responses of poison ivy (toxicodendron radicans) to elevated atmospheric C02: Reply

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This is an invited comment that was requested by the Editors of the journal Ecology. The authors of this comment previously published an article showing that poison ivy growth was enhanced in a controlled experiment in response to elevated atmospheric carbon dioxide. In this study the growth of po...

  14. Mycorrhizal mediation of soil organic carbon decomposition under elevated atmospheric carbon dioxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Significant effort in global change research has recently been directed towards assessing the potential of soil as a carbon sink under future atmospheric carbon dioxide scenarios. Attention has focused on the impact of elevated carbon dioxide on plant interactions with mycorrhizae, a symbiotic soil...

  15. Managing soils for long-term productivity

    PubMed Central

    Syers, J. K.

    1997-01-01

    Meeting the goal of long-term agricultural productivity requires that soil degradation be halted and reversed. Soil fertility decline is a key factor in soil degradation and is probably the major cause of declining crop yields. There is evidence that the contribution of declining soil fertility to soil degradation has been underestimated.
    Sensitivity to soil degradation is implicit in the assessment of the sustainability of land management practices, with wide recognition of the fact that soils vary in their ability to resist change and recover subsequent to stress. The concept of resilience in relation to sustainability requires further elaboration and evaluation.
    In the context of soil degradation, a decline in soil fertility is primarily interpreted as the depletion of organic matter and plant nutrients. Despite a higher turnover rate of organic matter in the tropics there is no intrinsic difference between the organic matter content of soils from tropical and temperate regions. The level of organic matter in a soil is closely related to the above and below ground inputs. In the absence of adequate organic material inputs and where cultivation is continuous, soil organic matter declines progressively. Maintaining the quantity and quality of soil organic matter should be a guiding principle in developing management practices.
    Soil microbial biomass serves as an important reservoir of nitrogen (N), phosphorus (P) and sulphur (S), and regulates the cycling of organic matter and nutrients. Because of its high turnover rate, microbial biomass reacts quickly to changes in management and is a sensitive indicator for monitoring and predicting changes in soil organic matter. Modelling techniques have been reasonably successful in predicting changes in soil organic matter with different organic material inputs, but there is little information from the tropics.
    Nutrient depletion through harvested crop components and residue removal, and by leaching and soil

  16. Response of tundra ecosystems to elevated atmospheric carbon dioxide. [Annual report

    SciTech Connect

    Oechel, W.C.; Grulke, N.E.

    1988-12-31

    Our past research shows that arctic tussock tundra responds to elevated atmospheric CO{sub 2} with marked increases in net ecosystem carbon flux and photosynthetic rates. However, at ambient temperatures and nutrient availabilities, homeostatic adjustments result in net ecosystem flux rates dropping to those found a contemporary CO{sub 2} levels within three years. Evidence for ecosystem-level acclimation in the first season of elevated CO{sub 2} exposure was found in 1987. Photosynthetic rates of Eriophorum vaginatum, the dominant species, adjusts to elevated CO{sub 2} within three weeks. Past research also indicates other changes potentially important to ecosystem structure and function. Elevated CO{sub 2} treatment apparently delays senescence and increases the period of positive photosynthetic activity. Recent results from the 1987 field season verify the results obtained in the 1983--1986 field seasons: Elevated CO{sub 2} resulted in increased ecosystem-level flux rates. Regressions fitted to the seasonal flux rates indicate an apparent 10 d extension of positive CO{sub 2} uptake reflecting a delay of the onset of plant dormancy. This delay in senescence could increase the frost sensitivity of the system. Major end points proposed for this research include the effects of elevated CO{sub 2} and the interaction of elevated atmospheric CO{sub 2} with elevated soil temperature and increased nutrient availability on: (1) Net ecosystem CO{sub 2} flux; (2) Net photosynthetic rates; (3) Patterns and resource controls on homeostatic adjustment in the above processes to elevated CO{sub 2}; (4) Plant-nutrient status, litter quality, and forage quality; (5) Soil-nutrient status; (6) Plant-growth pattern and shoot demography.

  17. Long-Term Changes in the Equatorial Pacific Trade Winds.

    NASA Astrophysics Data System (ADS)

    Clarke, Allan J.; Lebedev, Anna

    1996-05-01

    Past work has shown that surface zonal equatorial wind stress, zonally integrated from one side of the Pacific to the other, is the key variable for estimating long-term El Niño behavior in the eastern Pacific. The long-term behavior of this key variable is difficult to determine directly because of the paucity of the equatorial wind observations and because of false trends in the wind data introduced by gradual changes in the methods of wind measurement. However, surface pressure data generally does not suffer from these false trends and theory suggests that this key wind variable is linearly related to the difference (p) of surface atmospheric pressure between the eastern and western equatorial Pacific. Detrended COADS pressure in the eastern and western equatorial Pacific and post 1960 detrended equatorial wind stress zonally averaged across the Pacific were used to verify this relationship. Pressure difference and zonally averaged equatorial zonal windstress () were highly correlated (r = 0.90) and the regression also showed that advection of zonal momentum contributes substantially to the momentum balance in the equatorial atmospheric boundary layer. Further, hindcasts of eastern equatorial Pacific sea surface temperature and sea level indicated that from p was more accurate than from winds even since 1960 when wind data were more plentiful. This suggests that the simple pressure difference p is an effective way to monitor both in the past and in the future.Using the p time series as a proxy for zonally integrated wind stress suggests that the equatorial trades strengthened during the early and mid-1930s, weakened from the late 1930s to late 1950s, strengthened during the 1960s, and weakened rapidly since. This pattern is qualitatively consistent with the long record of sea surface temperature measurements at Puerto Chicama (Peru). The more recent rapid weakening is consistent with trends in several physical variables reported previously by others. The long-term

  18. Long-term measurements of trace gaseous pollutants over Beijing using Mini-MAX-DOAS instruments

    NASA Astrophysics Data System (ADS)

    Ma, Jianzhong; Jin, Junli; Shaiganfar, Reza; Wagner, Thomas

    2014-05-01

    Air quality in Beijing megacity has been of great concern in the atmospheric and environmental science community as well as public media. In addition to in situ measurements of ambient concentrations of air pollutants (e.g. NO2, SO2) near the ground, satellite data have also been used to analyze the long-term variation trend of urban pollution as well as the special emission control effect. However, the emission sources of pollutants in a megacity like Beijing are diverse and heterogeneously distributed in the urban canopy. Therefore, in situ surface measurement results may be quite different from one site to another depending on the representativeness of the chosen sites. Satellite measurements are found to have large biases in monitoring the air pollutant levels in a city due to both grid-smoothing and aerosol shielding effects. Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) is a passive remote sensing technology, which retrieves atmospheric trace gases by using scattered sun light from various elevation angles. Ground-based measurements by MAX-DOAS are especially sensitive to the tropospheric part of trace gas column, and can be used effectively to validate the satellite products for the troposphere. We have performed ground Mini-MAX-DOAS measurements at an urban site (39.95N, 116.32E) in Beijing since August 2008. The diurnal and seasonal variations of tropospheric NO2 vertical column densities were retrieved by analyzing the MAX-DOAS spectra obtained at this site. Such dataset were also used to validate the SCIMACHY and OMI satellite NO2 products for the period 2008-2009. Analyses of these MAX-DOAS spectra for SO2 and HCHO will be done in the near future to investigate the long-term variations of pollution level and character in Beijing over the past years.

  19. Impacts of elevated atmospheric CO2 and O3 on forests: phytochemistry, trophic interactions, and ecosystem dynamics.

    PubMed

    Lindroth, Richard L

    2010-01-01

    from this and related reviews is that the effects of elevated CO2 and O3 on plant chemistry and ecological interactions are highly context- and species-specific, thus frustrating attempts to identify general, global patterns. Many of the interactions that govern above- and below-ground community and ecosystem processes are chemically mediated, ultimately influencing terrestrial carbon sequestration and feeding back to influence atmospheric composition. Thus, the discipline of chemical ecology is fundamentally important for elucidating the impacts of humans on the health and sustainability of forest ecosystems. Future research should seek to increase the diversity of natural products, species, and biomes studied; incorporate long-term, multi-factor experiments; and employ a comprehensive “genes to ecosystems” perspective that couples genetic/genomic tools with the approaches of evolutionary and ecosystem ecology. PMID:20054619

  20. Long-term U. S. energy outlook

    SciTech Connect

    Friesen, G.

    1984-01-01

    Each year Chase Econometrics offers its clients a brief summary of the assumptions underlying the long-term energy forecast for the U.S. To illustrate the uncertainty involved in forecasting for the period to the year 2000, they choose to compare forecasts with some recent projections prepared by the Department of Energy's Office of Policy, Planning and Analysis for the annual National Energy Policy Plan supplement. Particular emphasis is placed on Scenario B, which is the mid-range reference case. As the introduction to the supplement emphasizes, the NEPP projections should not be considered a statement of the policy goals of the Reagan Administration. They represent an analysis of the possible evolution of U.S. energy markets, given current information and existing policies. The purpose of providing Scenario B as a reference case as well as Scenarios A and C as alternate cases is to show the sensitivity of oil price projections to small swings in energy demand.

  1. Long-term control of root growth

    DOEpatents

    Burton, Frederick G.; Cataldo, Dominic A.; Cline, John F.; Skiens, W. Eugene

    1992-05-26

    A method and system for long-term control of root growth without killing the plants bearing those roots involves incorporating a 2,6-dinitroaniline in a polymer and disposing the polymer in an area in which root control is desired. This results in controlled release of the substituted aniline herbicide over a period of many years. Herbicides of this class have the property of preventing root elongation without translocating into other parts of the plant. The herbicide may be encapsulated in the polymer or mixed with it. The polymer-herbicide mixture may be formed into pellets, sheets, pipe gaskets, pipes for carrying water, or various other forms. The invention may be applied to other protection of buried hazardous wastes, protection of underground pipes, prevention of root intrusion beneath slabs, the dwarfing of trees or shrubs and other applications. The preferred herbicide is 4-difluoromethyl-N,N-dipropyl-2,6-dinitro-aniline, commonly known as trifluralin.

  2. Long-term control of root growth

    SciTech Connect

    Burton, F.G.; Cataldo, D.A.; Cline, J.F.; Skiens, W.E.

    1992-05-26

    A method and system for long-term control of root growth without killing the plants bearing those roots involves incorporating a 2,6-dinitroaniline in a polymer and disposing the polymer in an area in which root control is desired. This results in controlled release of the substituted aniline herbicide over a period of many years. Herbicides of this class have the property of preventing root elongation without translocating into other parts of the plant. The herbicide may be encapsulated in the polymer or mixed with it. The polymer-herbicide mixture may be formed into pellets, sheets, pipe gaskets, pipes for carrying water, or various other forms. The invention may be applied to other protection of buried hazardous wastes, protection of underground pipes, prevention of root intrusion beneath slabs, the dwarfing of trees or shrubs and other applications. The preferred herbicide is 4-difluoromethyl-N,N-dipropyl-2,6-dinitro-aniline, commonly known as trifluralin. 7 figs.

  3. Long term thermoelectric module testing system.

    PubMed

    D'Angelo, Jonathan; Hogan, Timothy

    2009-10-01

    Thermoelectric generators can be used for converting waste heat into electric power. Significant interest in developing new materials in recent years has led to the discovery of several promising thermoelectrics, however, there can be considerable challenges in developing the materials into working devices. Testing and feedback is needed at each step to gain valuable information for identification of difficulties, quality of the materials and modules, repeatability in fabrication, and longevity of the devices. This paper describes a long-term module testing system for monitoring the output power of a module over extended testing times. To evaluate the system, we have tested commercially available thermoelectric modules over a one month time period. PMID:19895086

  4. Advanced long term cryogenic storage systems

    NASA Technical Reports Server (NTRS)

    Brown, Norman S.

    1987-01-01

    Long term, cryogenic fluid storage facilities will be required to support future space programs such as the space-based Orbital Transfer Vehicle (OTV), Telescopes, and Laser Systems. An orbital liquid oxygen/liquid hydrogen storage system with an initial capacity of approximately 200,000 lb will be required. The storage facility tank design must have the capability of fluid acquisition in microgravity and limit cryogen boiloff due to environmental heating. Cryogenic boiloff management features, minimizing Earth-to-orbit transportation costs, will include advanced thick multilayer insulation/integrated vapor cooled shield concepts, low conductance support structures, and refrigeration/reliquefaction systems. Contracted study efforts are under way to develop storage system designs, technology plans, test article hardware designs, and develop plans for ground/flight testing.

  5. Withdrawal from long-term benzodiazepine treatment.

    PubMed Central

    Petursson, H; Lader, M H

    1981-01-01

    Long-term, normal-dose benzodiazepine treatment was discontinued in 16 patients who were suspected of being dependent on their medication. The withdrawal was gradual, placebo-controlled, and double-blind. All the patients experienced some form of withdrawal reaction, which ranged from anxiety and dysphoria to moderate affective and perceptual changes. Symptom ratings rose as the drugs were discontinued, but usually subsided to prewithdrawal levels over the next two to four weeks. Other features of the withdrawal included disturbance of sleep and appetite and noticeable weight loss. Electroencephalography showed appreciable reduction in fast-wave activity as the drugs were withdrawn, and an improvement in psychological performance was recorded by the Digit Symbol Substitution Test. Because of the risk of dependence on benzodiazepines these agents should probably not be given as regular daily treatment for chronic anxiety. PMID:6114776

  6. Long term performance of radon mitigation systems

    SciTech Connect

    Prill, R.; Fisk, W.J.

    2002-03-01

    Researchers installed radon mitigation systems in 12 houses in Spokane, Washington and Coeur d'Alene, Idaho during the heating season 1985--1986 and continued to monitor indoor radon quarterly and annually for ten years. The mitigation systems included active sub-slab ventilation, basement over-pressurization, and crawlspace isolation and ventilation. The occupants reported various operational problems with these early mitigation systems. The long-term radon measurements were essential to track the effectiveness of the mitigation systems over time. All 12 homes were visited during the second year of the study, while a second set 5 homes was visited during the fifth year to determine the cause(s) of increased radon in the homes. During these visits, the mitigation systems were inspected and measurements of system performance were made. Maintenance and modifications were performed to improve system performance in these homes.

  7. Managing Records for the Long Term - 12363

    SciTech Connect

    Montgomery, John V.; Gueretta, Jeanie

    2012-07-01

    The U.S. Department of Energy (DOE) is responsible for managing vast amounts of information documenting historical and current operations. This information is critical to the operations of the DOE Office of Legacy Management. Managing legacy records and information is challenging in terms of accessibility and changing technology. The Office of Legacy Management is meeting these challenges by making records and information management an organizational priority. The Office of Legacy Management mission is to manage DOE post-closure responsibilities at former Cold War weapons sites to ensure the future protection of human health and the environment. These responsibilities include environmental stewardship and long-term preservation and management of operational and environmental cleanup records associated with each site. A primary organizational goal for the Office of Legacy Management is to 'Preserve, Protect, and Share Records and Information'. Managing records for long-term preservation is an important responsibility. Adequate and dedicated resources and management support are required to perform this responsibility successfully. Records tell the story of an organization and may be required to defend an organization in court, provide historical information, identify lessons learned, or provide valuable information for researchers. Loss of records or the inability to retrieve records because of poor records management processes can have serious consequences and even lead to an organisation's downfall. Organizations must invest time and resources to establish a good records management program because of its significance to the organization as a whole. The Office of Legacy Management will continue to research and apply innovative ways of doing business to ensure that the organization stays at the forefront of effective records and information management. DOE is committed to preserving records that document our nation's Cold War legacy, and the Office of Legacy

  8. Long-term dynamics of Typha populations

    USGS Publications Warehouse

    Grace, J.B.; Wetzel, R.G.

    1998-01-01

    The zonation of Typha populations in an experimental pond in Michigan was re-examined 15 years after the original sampling to gain insight into the long-term dynamics. Current distributions of Typha populations were also examined in additional experimental ponds at the site that have been maintained for 23 years. The zonation between T. latifolia and T. angustifolia in the previously studied pond 15 years after the initial sampling revealed that the density and distribution of shoots had not changed significantly. Thus, it appears that previously reported results (based on 7- year old populations) have remained consistent over time. Additional insight into the interaction between these two taxa was sought by comparing mixed and monoculture stands in five experimental ponds that have remained undisturbed for their 23-year history. The maximum depth of T. latifolia, the shallow- water species, was not significantly reduced when growing in the presence of the more flood tolerant T. angustifolia. In contrast, the minimum depth of T. angustifolia was reduced from 0 to 37 cm when in the presence of T. latifolia. When total populations were compared between monoculture and mixed stands, the average density of T. angustifolia shoots was 59.4 percent lower in mixed stands while the density of T. latifolia was 32 percent lower, with T. angustifolia most affected at shallow depths (reduced by 92 percent) and T. latifolia most affected at the deepest depths (reduced by 60 percent). These long-term observations indicate that competitive displacement between Typha taxa has remained stable over time.

  9. Short- and Long-Term Propagation of Spacecraft Orbits

    NASA Technical Reports Server (NTRS)

    Smith, John C., Jr.; Sweetser, Theodore; Chung, Min-Kun; Yen, Chen-Wan L.; Roncoli, Ralph B.; Kwok, Johnny H.; Vincent, Mark A.

    2008-01-01

    The Planetary Observer Planning Software (POPS) comprises four computer programs for use in designing orbits of spacecraft about planets. These programs are the Planetary Observer High Precision Orbit Propagator (POHOP), the Planetary Observer Long-Term Orbit Predictor (POLOP), the Planetary Observer Post Processor (POPP), and the Planetary Observer Plotting (POPLOT) program. POHOP and POLOP integrate the equations of motion to propagate an initial set of classical orbit elements to a future epoch. POHOP models shortterm (one revolution) orbital motion; POLOP averages out the short-term behavior but requires far less processing time than do older programs that perform long-term orbit propagations. POPP postprocesses the spacecraft ephemeris created by POHOP or POLOP (or optionally can use a less accurate internal ephemeris) to search for trajectory-related geometric events including, for example, rising or setting of a spacecraft as observed from a ground site. For each such event, POPP puts out such user-specified data as the time, elevation, and azimuth. POPLOT is a graphics program that plots data generated by POPP. POPLOT can plot orbit ground tracks on a world map and can produce a variety of summaries and generic ordinate-vs.-abscissa plots of any POPP data.

  10. Preeclampsia: long-term consequences for vascular health

    PubMed Central

    Amaral, Lorena M; Cunningham, Mark W; Cornelius, Denise C; LaMarca, Babbette

    2015-01-01

    Preeclampsia (PE) is a pregnancy-specific syndrome and one of the leading causes of preterm birth, neonatal and maternal morbidity and mortality. This disease is characterized by new onset hypertension usually in the third trimester of pregnancy and is sometimes associated with proteinuria, although proteinuria is not a requirement for the diagnosis of PE. In developing countries, women have a higher risk of death due to PE than more affluent countries and one of the most frequent causes of death is high blood pressure and stroke. Although PE only affects approximately 2%–8% of pregnancies worldwide it is associated with severe complications such as eclampsia, hemorrhagic stroke, hemolysis, elevated liver enzymes and low platelets (HELLP syndrome), renal failure and pulmonary edema. Importantly, there is no “cure” for the disease except for early delivery of the baby and placenta, leaving PE a health care risk for babies born from PE moms. In addition, PE is linked to the development of cardiovascular disease and stroke in women after reproductive age, leaving PE a risk factor for long-term health in women. This review will highlight factors implicated in the pathophysiology of PE that may contribute to long-term effects in women with preeclamptic pregnancies. PMID:26203257

  11. Preeclampsia: long-term consequences for vascular health.

    PubMed

    Amaral, Lorena M; Cunningham, Mark W; Cornelius, Denise C; LaMarca, Babbette

    2015-01-01

    Preeclampsia (PE) is a pregnancy-specific syndrome and one of the leading causes of preterm birth, neonatal and maternal morbidity and mortality. This disease is characterized by new onset hypertension usually in the third trimester of pregnancy and is sometimes associated with proteinuria, although proteinuria is not a requirement for the diagnosis of PE. In developing countries, women have a higher risk of death due to PE than more affluent countries and one of the most frequent causes of death is high blood pressure and stroke. Although PE only affects approximately 2%-8% of pregnancies worldwide it is associated with severe complications such as eclampsia, hemorrhagic stroke, hemolysis, elevated liver enzymes and low platelets (HELLP syndrome), renal failure and pulmonary edema. Importantly, there is no "cure" for the disease except for early delivery of the baby and placenta, leaving PE a health care risk for babies born from PE moms. In addition, PE is linked to the development of cardiovascular disease and stroke in women after reproductive age, leaving PE a risk factor for long-term health in women. This review will highlight factors implicated in the pathophysiology of PE that may contribute to long-term effects in women with preeclamptic pregnancies. PMID:26203257

  12. Long-term potentiation and long-term depression: a clinical perspective

    PubMed Central

    Bliss, Timothy V.P.; Cooke, Sam F

    2011-01-01

    Long-term potentiation and long-term depression are enduring changes in synaptic strength, induced by specific patterns of synaptic activity, that have received much attention as cellular models of information storage in the central nervous system. Work in a number of brain regions, from the spinal cord to the cerebral cortex, and in many animal species, ranging from invertebrates to humans, has demonstrated a reliable capacity for chemical synapses to undergo lasting changes in efficacy in response to a variety of induction protocols. In addition to their physiological relevance, long-term potentiation and depression may have important clinical applications. A growing insight into the molecular mechanisms underlying these processes, and technological advances in non-invasive manipulation of brain activity, now puts us at the threshold of harnessing long-term potentiation and depression and other forms of synaptic, cellular and circuit plasticity to manipulate synaptic strength in the human nervous system. Drugs may be used to erase or treat pathological synaptic states and non-invasive stimulation devices may be used to artificially induce synaptic plasticity to ameliorate conditions arising from disrupted synaptic drive. These approaches hold promise for the treatment of a variety of neurological conditions, including neuropathic pain, epilepsy, depression, amblyopia, tinnitus and stroke. PMID:21779718

  13. Elevated atmospheric carbon dioxide and leaf litter chemistry: Influences on microbial respiration and net nitrogen mineralization

    SciTech Connect

    Randlett, D.L.; Zak, D.R.; Pregitzer, K.S.; Curtis, P.S.

    1996-09-01

    Elevated atmospheric CO{sub 2} has the potential to influence rates of C and N cycling in terrestrial ecosystems by altering plant litter chemistry and slowing rates of organic matter decomposition. We tested the hypothesis that the chemistry of leaf litter produced at elevated CO{sub 2} would slow C and N transformations in soil. Soils were amended with Populus leaf produced under two levels of atmospheric CO{sub 2} (ambient and twice-ambient) and soil N availability (low and high). Kinetic parameters for microbial respiration and net N mineralization were determined on soil with and without litter during a 32-wk lab incubation. Product accumulation curves for CO{sub 2}-C and inorganic N were fit to a first order rate equation [y=A(1-e{sup -kt})] using nonlinear regression analyses. Although CO{sub 2} treatment affected soluble sugar concentration in leaf litter (ambient =120 g kg{sup -1}, elevated =130 g kg{sup -1}), it did not affect starch concentration or C/N ratio. Microbial respiration, microbial biomass, and leaf litter C/N ratio were affected by soil N availability but not by atmospheric CO{sub 2}. Net N mineralization was a linear function of time and was not significantly different for leaves grown at ambient (50 mg N kg{sup -1}) and elevated CO{sub 2} (35 mg N kg{sup -1}). Consequently, we found no evidence for the hypothesis that leaf litter produced at elevated atmospheric CO{sub 2} will dampen the rates of C and N cycling in soil. 35 refs., 1 fig., 4 tabs.

  14. Composition and decomposition of soybean and sorghum tissues grown under elevated atmospheric carbon dioxide

    SciTech Connect

    Henning, F.P.; Wood, C.W.; Rogers, H.H.; Runion, G.B.; Prior, S.A.

    1996-07-01

    It has been hypothesized that changes in both quantity and quality of plant residue inputs to soils as atmospheric carbon dioxide (CO{sub 2}) concentration increases may alter carbon (C) and nitrogen (N) turnover rates and pool sizes. We determined the effect of elevated atmospheric CO{sub 2} on plant tissue quality, and how modifications in tissue quality affect C and N mineralization. Soybean and sorghum were grown under elevated (704.96 {plus_minus} 0.33 {mu}mol CO{sub 2} mol{sup {minus}1}) and ambient (357.44 {plus_minus} 0.12 {mu}mol CO{sub 2} mol{sup {minus}1}) atmospheric CO{sub 2} in open-top chambers. Leaf and stem tissues were separated form harvested plants and analyzed for C,N, lignin, and cellulose. Tissues were applied to Norfolk loamy sand (fine-loamy, siliceous, thermic Typic Kandiudult) and aerobically incubated for 70-d to determine C and N mineralization, C turnover, relative N mineralization, and C/N mineralized. Elevated CO{sub 2} had no effect on plant residue C concentration, but N concentration of soybean leaves and stems and sorghum stems was reduced; however, CO{sub 2} enrichment increased C/N ratio and lignin concentration for only sorghum stems and soybean leaves, respectively. Source of plant residue (i.e., produced under either elevated or ambient CO{sub 2}) had no impact on soil C turnover, relative N mineralization, cumulative C and N mineralization, and C/N mineralized. These data suggest that increasing atmospheric CO{sub 2} will have little effect on composition or decomposition of field crop residues. Thus, since CO{sub 2} enrichment results in increased photosynthetic C fixation, the possibility exists for increased soil C storage under field crops in an elevated CO{sub 2} world. 29 refs., 4 figs., 4 tabs.

  15. Long-term Solar Irradiance Variability: 1984-1989 Observations

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III

    1990-01-01

    Long-term variability in the total solar irradiance has been observed in the Earth Radiation Budget Experiment (ERBE) solar monitor measurements. The monitors have been used to measure the irradiance from the Earth Radiation Budget Satellite (ERBS) and the National Oceanic and Atmospheric Administration NOAA-9 and NOAA-10 spacecraft platforms since October 25, 1984, January 23, 1985, and October 22, 1986, respectively. Before September 1986, the ERBS irradiance values were found to be decreasing -0.03 percent per year. This period was marked by decreasing solar magnetic activity. Between September 1986 and mid-1989, the irradiance values increased approximately 0.1 percent. The latter period was marked by increasing solar activity which was associated with the initiations of the sunspot cycle number 22 and of a new 22-year Hale solar magnetic cycle. Therefore, long-term solar-irradiance variability appears to be correlated directly with solar activity. The maximum smoothed sunspot number occurred during September 1989, according to the Sunspot Index Data Center. Therefore, the recent irradiance increasing trend should disappear during early 1990 and change into a decreasing trend if the observed irradiance variability is correlated more so with the 11-year sunspot cycle than the 22-year Hale cycle. The ERBE irradiance values are presented and compared with sunspot activity for the 1984 to 1989 period. The ERBE values are compared with those available from the Nimbus-7 and Solar Maximum Mission spacecraft experiments.

  16. Long-term observations of tropospheric NO2 from satellite

    NASA Astrophysics Data System (ADS)

    Richter, Andreas; Hilboll, Andreas; Noguchi, Katsuyuki; Leitao, Joana; Burrows, John P.

    Nitrogen oxides (NOx = NO + NO2 ) are key species in atmospheric chemistry. Together with volatile organic compounds they determine the amount of ozone present in the troposphere. Through the formation of nitric acid they are involved in acid rain formation and in addition they contribute to radiative forcing both directly and indirectly. As nitrogen dioxide adversely affects human health it is also regulated by environmental laws. While ground-based networks provide long-term data of surface concentrations of nitrogen oxides at high temporal resolution in many countries, truly global observations can only be performed from space. By using the Differential Optical Absorption Spectroscopy (DOAS) method on spectrally resolved UV/vis measurements of scattered sunlight, column amounts of NO2 can be determined from nadir satellite observations. With additional assumptions on stratospheric NO2 and the radiative transfer, the tropospheric NO2 amounts can be retrieved. In this work, satellite observations of NO2 from several sensors (GOME, SCIAMACHY, OMI, and GOME-2) are used to study the long-term evolution of tropospheric NO2 amounts on a global scale. A particular focus is on the comparison of results retrieved from the different sensors in times of overlapping measurements and the degree of consistency achieved in regions of both large and small pollution signals. The effects of sampling statistics, time of overpass and spatial resolution are discussed as well as the influence of clouds.

  17. Global Horizontal Irradiance Anomalies in Long Term Series Over India

    NASA Astrophysics Data System (ADS)

    Cony, Marco; Liria, Juan; Weisenberg, Ralf; Serrano, Enrique

    2014-05-01

    India has a high potential for solar energy applications due to its geographic position within the Sun Belt and the large number of cloudless days in many regions of the country. However, certain regions of India, particularly those largely populated, can exhibit large aerosol loading in the atmosphere as a consequence of anthropogenic emissions that could have a negative feedback in the solar resource potential. This effect, named as solar dimming, has already been observed in India, and in some other regions in the world, by some authors using ground data from the last two decades. The recent interest in the promotion of solar energy applications in India highlights the need of extending and improving the knowledge of the solar radiation resources in this country, since most of the long term measurements available correspond to global horizontal radiation (GHI) and most of them are also located big cities or highly populated areas. In addition, accurate knowledge on the aerosol column quantification and on its dynamical behavior with high spatial resolution is particularly important in the case of India, due to their impact on direct normal irradiation. Long term studies of solar irradiation over India can be performed using monthly means of GHI measurements from the Indian Meteorological Department. Ground data are available from 1964 till today through the World Radiation Data Centre that publish these values in the web. This work shows a long term analysis of GHI using anomalies techniques over ten different sites over India. Besides, techniques of linear trends have been applied for to show the evolution over this period. The analysis of anomalies has also found two periods of different behavior. From 1964 till 1988 the anomalies observed were positive and the last 20 years seems to be a period of negative anomalies. The results exhibit a decreasing trend and negative anomalies confirming thus the darkening effect already reported by solar dimming studies

  18. LONG-TERM MONITORING SENSOR NETWORK

    SciTech Connect

    Stephen P. Farrington; John W. Haas; Neal Van Wyck

    2003-10-16

    Long-term monitoring (LTM) associated with subsurface contamination sites is a key element of Long Term Stewardship and Legacy Management across the Department of Energy (DOE) complex. However, both within the DOE and elsewhere, LTM is an expensive endeavor, often exceeding the costs of the remediation phase of a clean-up project. The primary contributors to LTM costs are associated with labor. Sample collection, storage, preparation, analysis, and reporting can add a significant financial burden to project expense when extended over many years. Development of unattended, in situ monitoring networks capable of providing quantitative data satisfactory to regulatory concerns has the potential to significantly reduce LTM costs. But survival and dependable operation in a difficult environment is a common obstacle to widespread use across the DOE complex or elsewhere. Deploying almost any sensor in the subsurface for extended periods of time will expose it to chemical and microbial degradation. Over the time-scales required for in situ LTM, even the most advanced sensor systems may be rendered useless. Frequent replacement or servicing (cleaning) of sensors is expensive and labor intensive, offsetting most, if not all, of the cost savings realized with unattended, in situ sensors. To enable facile, remote monitoring of contaminants and other subsurface parameters over prolonged periods, Applied Research Associates, Inc has been working to develop an advanced LTM sensor network consisting of three key elements: (1) an anti-fouling sensor chamber that can accommodate a variety of chemical and physical measurement devices based on electrochemical, optical and other techniques; (2) two rapid, cost effective, and gentle means of emplacing sensor packages either at precise locations directly in the subsurface or in pre-existing monitoring wells; and (3) a web browser-based data acquisition and control system (WebDACS) utilizing field-networked microprocessor-controlled smart

  19. Effects of Elevated CO2 Atmospheric CO2 on Soil Efflux in Conventional and Conservation Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated atmospheric CO2 can affect both the quantity and quality of plant tissues, which will impact the cycling and storage of carbon within plant/soil systems and the rate of CO2 release back to the atmosphere. Research is needed to more accurately quantify the effects of elevated CO2 on soil CO...

  20. Treatment for childhood cancer -- long-term risks

    MedlinePlus

    ... ency/patientinstructions/000849.htm Treatment for childhood cancer - long-term risks To use the sharing features on ... has. Being aware of your child's risk of long-term health problems can help you follow-up ...

  1. Long-term corrosion testing pan.

    SciTech Connect

    Wall, Frederick Douglas; Brown, Neil R.

    2008-08-01

    This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing needs. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to meet all future testing needs, given that all testing is consolidated to a single location. This report is a revision to SAND2007-7027 to address DOE comments and add a series of tests to address NWTRB recommendations.

  2. Long-term corrosion testing plan.

    SciTech Connect

    Wall, Frederick Douglas; Brown, Neil R.

    2009-02-01

    This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing program. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to accommodate all future testing, given that all testing is consolidated to a single location. This report is a revision to SAND2008-4922 to address DOE comments.

  3. Transuranic waste: long-term planning

    SciTech Connect

    Young, K.C.

    1985-07-01

    Societal concerns for the safe handling and disposal of toxic waste are behind many of the regulations and the control measures in effect today. Transuranic waste, a specific category of toxic (radioactive) waste, serves as a good example of how regulations and controls impact changes in waste processing - and vice versa. As problems would arise with waste processing, changes would be instituted. These changes improved techniques for handling and disposal of transuranic waste, reduced the risk of breached containment, and were usually linked with regulatory changes. Today, however, we face a greater public awareness of and concern for toxic waste control; thus, we must anticipate potential problems and work on resolving them before they can become real problems. System safety analyses are valuable aids in long-term planning for operations involving transuranic as well as other toxic materials. Examples of specific system safety analytical methods demonstrate how problems can be anticipated and resolution initiated in a timely manner having minimal impacts upon allocation of resource and operational goals. 7 refs., 1 fig.

  4. Long-term predictions using natural analogues

    SciTech Connect

    Ewing, R.C.

    1995-09-01

    One of the unique and scientifically most challenging aspects of nuclear waste isolation is the extrapolation of short-term laboratory data (hours to years) to the long time periods (10{sup 3}-10{sup 5} years) required by regulatory agencies for performance assessment. The direct validation of these extrapolations is not possible, but methods must be developed to demonstrate compliance with government regulations and to satisfy the lay public that there is a demonstrable and reasonable basis for accepting the long-term extrapolations. Natural systems (e.g., {open_quotes}natural analogues{close_quotes}) provide perhaps the only means of partial {open_quotes}validation,{close_quotes} as well as data that may be used directly in the models that are used in the extrapolation. Natural systems provide data on very large spatial (nm to km) and temporal (10{sup 3}-10{sup 8} years) scales and in highly complex terranes in which unknown synergisms may affect radionuclide migration. This paper reviews the application (and most importantly, the limitations) of data from natural analogue systems to the {open_quotes}validation{close_quotes} of performance assessments.

  5. [Long term adherence to HAART in Senegal].

    PubMed

    Bastard, M; Fall, M Basty Koita

    2014-10-01

    Adherence is one of the main predictors of antiretroviral treatment success. A governmental initiative was launched in 1998 for HIV-infected patients in Senegal to provide access to highly active antiretroviral therapy (HAART). Adherence measurements, defined as pills taken/pills prescribed, were assessed between November 1999 and June 2010 using a pill count along with a questionnaire for 330 patients. Predictors of adherence and identification of adherence trajectories were explored through latent class mixed model. We also performed a survival analysis using Cox proportional hazard model. Three adherence behaviours were revealed as well as a better adherence for women. A third of patients had a high adherence trajectory over time and a third had an intermediate one. Male gender and low adherence behaviour over time were independently associated with a higher mortality rate. This study shows that an overall good adherence can be obtained in the long term in Senegal, suggests a better adherence for women and points out a large subsample of patients with intermediate level of adherence behaviour who are at risk for developing resistance to antiretroviral drugs. PMID:24615434

  6. Long-term outcome in aqueductal stenosis.

    PubMed

    Villani, R; Tomei, G; Gaini, S M; Grimoldi, N; Spagnoli, D; Bello, L

    1995-03-01

    In this study, 78 patients with aqueductal stenosis were submitted to detailed neurodevelopmental assessment with a follow-up of 5-25 years. Sixty-eight percent of patients were categorized as normal; they either attended normal school courses or had regular jobs. Among these, 34% had some motor abnormalities (ataxia, mild hemiparesis, visual disturbances). Twenty-four percent (19 cases) were moderately disabled (trainable retardation) and 8% (6 cases) were severely handicapped. Epilepsy was observed in 13% of the cases. Incidence of recurrent and generalized seizures paralleled neurodevelopmental outcome (5% in normal, 16% in moderately disabled and 50% in severely disabled patients). Endocrine dysfunctions were evident in 28% of the cases and were characterized by precocious or delayed puberty, amenorrhea and somatic underdevelopment. No patient with ventricular enlargement and a cortical mantle width below 20 mm showed a good outcome. Large ventricles were compatible with normal mental development when compensated with a corresponding cranial vault enlargement. In patients with normal mental status and motor abnormalities, long-term CT scan findings revealed the presence of focal brain abnormalities (poroencephaly, brain atrophy, calcifications, extracerebral collections). PMID:7773981

  7. Alpine Soils as long-term Bioindicators

    NASA Astrophysics Data System (ADS)

    Nestroy, O.

    2009-04-01

    Alpine soils as long-term bioindicators The introductory words concern the definitions and peculiarities of alpine soils and their position in the Austrian Soil Classification 2000 in comparison with the World Reference Base for Soil Resources 2006. The important parameters for genesis and threats for these soils in steep and high positions are discussed. It must be emphasized that the main threats are the very different kinds of erosion e.g. by water, wind and snow, and also by skiing (end of season) as well as and mountain-biking (mainly summer-sport). Due the very slow regeneration and - in this connection - due to the very slow changes of the soil entities, these soils give an utmost importance as a long-time bioindicator. With regard to the climate change one can assume an increase in the content of organic matter on site, but also an increase of erosion and mass movement on the other site, e. g. in kind of "plaiken" (soil slide) as result of an increasing intensity of rainfall. It lies partly in our hands to diminish the number and the intensity of the threats, we can influence the soil development, but the result to reach a new ecological equilibrium is very long - in case of alpine soil more than two generations.

  8. Neurological long term consequences of deep diving.

    PubMed Central

    Todnem, K; Nyland, H; Skeidsvoll, H; Svihus, R; Rinck, P; Kambestad, B K; Riise, T; Aarli, J A

    1991-01-01

    Forty commercial saturation divers, mean age 34.9 (range 24-49) years, were examined one to seven years after their last deep dive (190-500 metres of seawater). Four had by then lost their divers' licence because of neurological problems. Twenty seven (68%) had been selected by neurological examination and electroencephalography before the deep dives. The control group consisted of 100 men, mean age 34.0 (range 22-48) years. The divers reported significantly more symptoms from the nervous system. Concentration difficulties and paraesthesia in feet and hands were common. They had more abnormal neurological findings by neurological examination compatible with dysfunction in the lumbar spinal cord or roots. They also had a larger proportion of abnormal electroencephalograms than the controls. The neurological symptoms and findings were highly significantly correlated with exposure to deep diving (depth included), but even more significantly correlated to air and saturation diving and prevalence of decompression sickness. Visual evoked potentials, brainstem auditory evoked potentials, and magnetic resonance imaging of the brain did not show more abnormal findings in the divers. Four (10%) divers had had episodes of cerebral dysfunction during or after the dives; two had had seizures, one had had transitory cerebral ischaemia and one had had transitory global amnesia. It is concluded that deep diving may have a long term effect on the nervous system of the divers. PMID:2025592

  9. The long-term variability of Vega

    NASA Astrophysics Data System (ADS)

    Butkovskaya, V.; Plachinda, S.; Valyavin, G.; Baklanova, D.; Lee, B.-C.

    2011-12-01

    Over the time of 60 years Vega (α Lyrae = HD 172167, A0V) has been generally accepted as a standard star in the near-infrared, optical, and ultraviolet regions. But is the spectrophotometric standard Vega really non-variable star? Researchers give very different answers to this question. We aim to search a periodicity in our results of spectropolarimetric study of Vega, namely periodic variations in equivalent width of the spectral lines and longitudinal magnetic field measurements. High-accuracy spectropolarimetric observations of Vega have been performed during 26 nights from 1997 to 2010 using the Coudé spectrograph of the 2.6-m Shain reflector at the Crimean Astrophysical Observatory (CrAO, Ukraine) and during 4 nights in 2007 and 2008 using the echelle spectrograph BOES at the Bohyunsan Optical Astronomy Observatory (BOAO, South Korea). The long-term (year-to-year) variability of Vega was confirmed. It was concluded that this variability does not have magnetic nature. The paper is dedicated to the memory of V.P. Merezhin.

  10. Long-term intraperitoneal insulin delivery.

    PubMed Central

    Pitt, H A; Saudek, C D; Zacur, H A

    1992-01-01

    Over the past 5 years, 21 patients with insulin-dependent diabetes mellitus have been managed at the Johns Hopkins Medical Institutions with variable rate, remotely controlled implanted insulin pumps. To date, nearly 70 patient-years of experience has been gained with intraperitoneal delivery of a new U-400 insulin with a surfactant. All 21 patients are alive after a mean of 39.3 months (range, 10 to 65 months) after insulin pump implantation. Nineteen of the 21 patients remain on intraperitoneal insulin, for a 5-year actuarial system survival of 90%. Glucose control was improved, especially during the first 16 months after pump implantation, without an increased incidence of severe hypoglycemia. Catheter blockage has been a significant problem, occurring in nine of the 21 patients (43%). Catheter occlusion has been successfully managed, however, with laparoscopic repair in seven of 10 attempts or with catheter change in four of five patients. Nevertheless, quality of life and patient acceptance remain excellent. Moreover, pre-existing nephropathy, neuropathy, and retinopathy have been surprisingly stable. With an aggressive policy of catheter change or laparoscopic clearance of catheter blockage, long-term intraperitoneal insulin delivery is now a safe and effective treatment for type I diabetics. PMID:1417197

  11. Intermediate- and long-term earthquake prediction.

    PubMed

    Sykes, L R

    1996-04-30

    Progress in long- and intermediate-term earthquake prediction is reviewed emphasizing results from California. Earthquake prediction as a scientific discipline is still in its infancy. Probabilistic estimates that segments of several faults in California will be the sites of large shocks in the next 30 years are now generally accepted and widely used. Several examples are presented of changes in rates of moderate-size earthquakes and seismic moment release on time scales of a few to 30 years that occurred prior to large shocks. A distinction is made between large earthquakes that rupture the entire downdip width of the outer brittle part of the earth's crust and small shocks that do not. Large events occur quasi-periodically in time along a fault segment and happen much more often than predicted from the rates of small shocks along that segment. I am moderately optimistic about improving predictions of large events for time scales of a few to 30 years although little work of that type is currently underway in the United States. Precursory effects, like the changes in stress they reflect, should be examined from a tensorial rather than a scalar perspective. A broad pattern of increased numbers of moderate-size shocks in southern California since 1986 resembles the pattern in the 25 years before the great 1906 earthquake. Since it may be a long-term precursor to a great event on the southern San Andreas fault, that area deserves detailed intensified study. PMID:11607658

  12. Intermediate- and long-term earthquake prediction.

    PubMed Central

    Sykes, L R

    1996-01-01

    Progress in long- and intermediate-term earthquake prediction is reviewed emphasizing results from California. Earthquake prediction as a scientific discipline is still in its infancy. Probabilistic estimates that segments of several faults in California will be the sites of large shocks in the next 30 years are now generally accepted and widely used. Several examples are presented of changes in rates of moderate-size earthquakes and seismic moment release on time scales of a few to 30 years that occurred prior to large shocks. A distinction is made between large earthquakes that rupture the entire downdip width of the outer brittle part of the earth's crust and small shocks that do not. Large events occur quasi-periodically in time along a fault segment and happen much more often than predicted from the rates of small shocks along that segment. I am moderately optimistic about improving predictions of large events for time scales of a few to 30 years although little work of that type is currently underway in the United States. Precursory effects, like the changes in stress they reflect, should be examined from a tensorial rather than a scalar perspective. A broad pattern of increased numbers of moderate-size shocks in southern California since 1986 resembles the pattern in the 25 years before the great 1906 earthquake. Since it may be a long-term precursor to a great event on the southern San Andreas fault, that area deserves detailed intensified study. Images Fig. 1 PMID:11607658

  13. Long-term adequacy of metal resources

    USGS Publications Warehouse

    Singer, D.A.

    1977-01-01

    Although the earth's crust contains vast quantities of metals, extraction technologies and associated costs are inextricably bound to three fundamental geological factors - the amount of metal available in the earth's crust in each range of grades, the mineralogical form and chemical state of the metal, and the spatial distribution of the metal. The energy required to recover a given amount of metal increases substantially as grade declines. Most metal is produced from sulphide or oxide minerals, whereas most metal in the crust may be locked in the structures of the more refractory silicates. Recovery from silicate minerals could require orders of magnitude more energy than that used at present as also could exploitation of small, widely scattered or thin, deeply buried deposits. Although specific information on the fundamental factors is not available, each factor must in turn tend to further restrict exploitation. Independence of average grade and tonnage for many deposit types further reduces the availability of rock as a source of metal. In the long term, effects of these factors will be large increases in price for many metals. ?? 1977.

  14. Long Term Storage of Lyophilized Liposomal Formulations

    PubMed Central

    Payton, N.M.; Wempe, M.F.; Xu, Y.; Anchordoquy, T.J.

    2014-01-01

    Because aqueous liposomal formulations containing multiply unsaturated lipids are susceptible to chemical degradation, these formulations are often lyophilized. Despite their limited chemical stability, interest in the use of multiply unsaturated lipids to promote intracellular delivery has increased considerably in recent years. The goal of the current study was to examine the long term storage stability of lyophilized formulations containing lipids with increasing levels of unsaturation, and various strategies which can be employed to improve stability. Aqueous lipid-trehalose formulations containing 1,2-dilinolenoyl-sn-glycero-3-phosphocholine (DLPC), 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (DLinPC) or 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) were lyophilized and stored at temperatures ranging from 4°C to 60°C. We observed that the lipid degradation rate increased as the storage temperature and unsaturation level were increased. Even the cleanest sugars which are available commercially contain iron contaminants, and it was observed that the chelation of these iron contaminants significantly improved the stability of DLPC during storage. However, the glass transition temperature of the sugar which was included in the formulation, the reduction of the oxygen in the aqueous sample prior to lyophilization, the inclusion of helper lipids (i.e., cholesterol), and the rate of freezing did not significantly improve stability. PMID:25308534

  15. 22 CFR 228.12 - Long-term leases.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Long-term leases. 228.12 Section 228.12 Foreign... Transactions for USAID Financing § 228.12 Long-term leases. Any commodity obtained under a long-term lease..., a long-term lease is defined as a single lease of more than 180 days, or repetitive or...

  16. 22 CFR 228.12 - Long-term leases.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Long-term leases. 228.12 Section 228.12 Foreign... Transactions for USAID Financing § 228.12 Long-term leases. Any commodity obtained under a long-term lease..., a long-term lease is defined as a single lease of more than 180 days, or repetitive or...

  17. Effect of elevated atmospheric CO/sub 2/ on plant communities. Final report

    SciTech Connect

    Bazzaz, F.A.

    1984-10-01

    We have studied the effects of elevated atmospheric carbon dioxide on communities of colonizing annual plants, crop plants, and deciduous forest trees. We observe differential effects on different species with regard to growth, biomass, phenology, resource allocation, photosynthesis, water-use efficiency, flowering, and fruiting. We conclude that competitive relations among plants are likely to change as global atmospheric CO/sub 2/ increases, and that therefore there will be longterm changes in the composition of natural communities. More research will be necessary before any but the very broadest conclusions can be made about what direction these community changes are likely to take. 10 references, 9 figures.

  18. Effects of Elevated Atmospheric CO2 on Rhizosphere Soil Microbial Communities in a Mojave Desert Ecosystem

    PubMed Central

    Nguyen, L.M.; Buttner, M.P.; Cruz, P.; Smith, S.D.; Robleto, E.A.

    2011-01-01

    The effects of elevated atmospheric carbon dioxide [CO2] on microbial communities in arid rhizosphere soils beneath Larrea tridentata were examined. Roots of Larrea were harvested from plots fumigated with elevated or ambient levels of [CO2] using Free-Air CO2 Enrichment (FACE) technology. Twelve bacterial and fungal rRNA gene libraries were constructed, sequenced and categorized into operational taxonomical units (OTUs). There was a significant decrease in OTUs within the Firmicutes (bacteria) in elevated [CO2], and increase in Basiomycota (fungi) in rhizosphere soils of plots exposed to ambient [CO2]. Phylogenetic analyses indicated that OTUs belonged to a wide range of bacterial and fungal taxa. To further study changes in bacterial communities, Quantitative Polymerase Chain Reaction (QPCR) was used to quantify populations of bacteria in rhizosphere soil. The concentration of total bacteria 16S rDNA was similar in conditions of enriched and ambient [CO2]. However, QPCR of Gram-positive microorganisms showed a 43% decrease in the population in elevated [CO2]. The decrease in representation of Gram positives and the similar values for total bacterial DNA suggest that the representation of other bacterial taxa was promoted by elevated [CO2]. These results indicate that elevated [CO2] changes structure and representation of microorganisms associated with roots of desert plants. PMID:21779135

  19. Elevated atmospheric CO2 levels affect community structure of rice root-associated bacteria

    PubMed Central

    Okubo, Takashi; Liu, Dongyan; Tsurumaru, Hirohito; Ikeda, Seishi; Asakawa, Susumu; Tokida, Takeshi; Tago, Kanako; Hayatsu, Masahito; Aoki, Naohiro; Ishimaru, Ken; Ujiie, Kazuhiro; Usui, Yasuhiro; Nakamura, Hirofumi; Sakai, Hidemitsu; Hayashi, Kentaro; Hasegawa, Toshihiro; Minamisawa, Kiwamu

    2015-01-01

    A number of studies have shown that elevated atmospheric CO2 ([CO2]) affects rice yields and grain quality. However, the responses of root-associated bacteria to [CO2] elevation have not been characterized in a large-scale field study. We conducted a free-air CO2 enrichment (FACE) experiment (ambient + 200 μmol.mol−1) using three rice cultivars (Akita 63, Takanari, and Koshihikari) and two experimental lines of Koshihikari [chromosome segment substitution and near-isogenic lines (NILs)] to determine the effects of [CO2] elevation on the community structure of rice root-associated bacteria. Microbial DNA was extracted from rice roots at the panicle formation stage and analyzed by pyrosequencing the bacterial 16S rRNA gene to characterize the members of the bacterial community. Principal coordinate analysis of a weighted UniFrac distance matrix revealed that the community structure was clearly affected by elevated [CO2]. The predominant community members at class level were Alpha-, Beta-, and Gamma-proteobacteria in the control (ambient) and FACE plots. The relative abundance of Methylocystaceae, the major methane-oxidizing bacteria in rice roots, tended to decrease with increasing [CO2] levels. Quantitative PCR revealed a decreased copy number of the methane monooxygenase (pmoA) gene and increased methyl coenzyme M reductase (mcrA) in elevated [CO2]. These results suggest elevated [CO2] suppresses methane oxidation and promotes methanogenesis in rice roots; this process affects the carbon cycle in rice paddy fields. PMID:25750640

  20. Effects of Elevated Atmospheric CO(2) on Rhizosphere Soil Microbial Communities in a Mojave Desert Ecosystem.

    PubMed

    Nguyen, L M; Buttner, M P; Cruz, P; Smith, S D; Robleto, E A

    2011-10-01

    The effects of elevated atmospheric carbon dioxide [CO(2)] on microbial communities in arid rhizosphere soils beneath Larrea tridentata were examined. Roots of Larrea were harvested from plots fumigated with elevated or ambient levels of [CO(2)] using Free-Air CO(2) Enrichment (FACE) technology. Twelve bacterial and fungal rRNA gene libraries were constructed, sequenced and categorized into operational taxonomical units (OTUs). There was a significant decrease in OTUs within the Firmicutes (bacteria) in elevated [CO(2)], and increase in Basiomycota (fungi) in rhizosphere soils of plots exposed to ambient [CO(2)]. Phylogenetic analyses indicated that OTUs belonged to a wide range of bacterial and fungal taxa. To further study changes in bacterial communities, Quantitative Polymerase Chain Reaction (QPCR) was used to quantify populations of bacteria in rhizosphere soil. The concentration of total bacteria 16S rDNA was similar in conditions of enriched and ambient [CO(2)]. However, QPCR of Gram-positive microorganisms showed a 43% decrease in the population in elevated [CO(2)]. The decrease in representation of Gram positives and the similar values for total bacterial DNA suggest that the representation of other bacterial taxa was promoted by elevated [CO(2)]. These results indicate that elevated [CO(2)] changes structure and representation of microorganisms associated with roots of desert plants. PMID:21779135

  1. 26 CFR 1.460-1 - Long-term contracts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 6 2011-04-01 2011-04-01 false Long-term contracts. 1.460-1 Section 1.460-1...) INCOME TAXES (CONTINUED) Taxable Year for Which Items of Gross Income Included § 1.460-1 Long-term... the manufacture, building, installation, or construction of property is a long-term contract...

  2. 22 CFR 228.18 - Long-term leases.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Long-term leases. 228.18 Section 228.18 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES FOR PROCUREMENT OF COMMODITIES AND SERVICES FINANCED BY... USAID Financing § 228.18 Long-term leases. Any commodity obtained under a long-term lease agreement...

  3. 26 CFR 1.460-1 - Long-term contracts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 6 2014-04-01 2014-04-01 false Long-term contracts. 1.460-1 Section 1.460-1...) INCOME TAXES (CONTINUED) Taxable Year for Which Items of Gross Income Included § 1.460-1 Long-term... the manufacture, building, installation, or construction of property is a long-term contract...

  4. 22 CFR 228.18 - Long-term leases.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Long-term leases. 228.18 Section 228.18 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES FOR PROCUREMENT OF COMMODITIES AND SERVICES FINANCED BY... USAID Financing § 228.18 Long-term leases. Any commodity obtained under a long-term lease agreement...

  5. 26 CFR 1.460-1 - Long-term contracts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 6 2013-04-01 2013-04-01 false Long-term contracts. 1.460-1 Section 1.460-1...) INCOME TAXES (CONTINUED) Taxable Year for Which Items of Gross Income Included § 1.460-1 Long-term... the manufacture, building, installation, or construction of property is a long-term contract...

  6. 17 CFR 256.224 - Other long-term debt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Other long-term debt. 256.224 Section 256.224 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) UNIFORM... COMPANY ACT OF 1935 6. Long-Term Debt § 256.224 Other long-term debt. This account shall include all...

  7. 17 CFR 256.224 - Other long-term debt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Other long-term debt. 256.224 Section 256.224 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) UNIFORM... COMPANY ACT OF 1935 6. Long-Term Debt § 256.224 Other long-term debt. This account shall include all...

  8. 22 CFR 228.18 - Long-term leases.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Long-term leases. 228.18 Section 228.18 Foreign Relations AGENCY FOR INTERNATIONAL DEVELOPMENT RULES FOR PROCUREMENT OF COMMODITIES AND SERVICES FINANCED BY... USAID Financing § 228.18 Long-term leases. Any commodity obtained under a long-term lease agreement...

  9. 3 CFR - Long-Term Gulf Coast Restoration Support Plan

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 3 The President 1 2011-01-01 2011-01-01 false Long-Term Gulf Coast Restoration Support Plan Presidential Documents Other Presidential Documents Memorandum of June 30, 2010 Long-Term Gulf Coast... help the Gulf Coast and its people recover from this tragedy. A long-term plan to restore the...

  10. 78 FR 36449 - State Long-Term Care Ombudsman Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-18

    ... HUMAN SERVICES Administration on Aging 45 CFR Parts 1321 and 1327 RIN 0985-AA08 State Long-Term Care... request for comments, to implement provisions of the Older Americans Act, the State Long-Term Care... determining State compliance in carrying out the Long-Term Care Ombudsman program functions. This...

  11. Soil-plant-atmosphere processes along an elevation gradient in a dry alpine valley

    NASA Astrophysics Data System (ADS)

    Della Chiesa, Stefano; Bertoldi, Giacomo; Niedrist, Georg Georg; Tappeiner, Ulrike

    2013-04-01

    In mountain regions soil-plant-atmosphere processes exhibit rapid changes within short distance due to the complex pattern of topography and atmospheric processes. An elevation transect can be seen as a proxy of climate change (CC), as it affects air temperature, precipitation amount and its partitioning into snow and rain, snow cover duration, and the resulting changing length of vegetation period. In order to quantitatively investigate the exchange of energy, water and carbon with respect to elevation for mountain grassland ecosystems within an inner dry alpine valley, a transect of three micro-meteorological stations was established since 2009 in the Venosta valley (South Tyrol, Italy). It has been designed with three stations, with an elevation difference among the stations of 500 m, which means an average temperature gradient of 2.7 K. In this contribution, the GEOtop-dv model was employed to simulate the effects of the elevation gradient on snow, soil moisture, evapotranspiration (ET) and above ground net primary production (ANPP) dynamics in two years with different climatic conditions. Simulations have been validated with observations of soil moisture, snow height, ANPP and eddy-covariance measured ET. Considering the observed contrasting natural trends of increasing precipitation and of decreasing temperature with higher elevation, numerical simulation results show that, in this type of climate, snow dynamics are highly nonlinear with the elevation due to differential precipitation partitioning in early winter and spring. Despite the relatively cold climatic conditions, soil moisture dynamics indicate that severe drought occurs in the bottom of the valley, while at the higher elevations cold temperatures limit growing season duration, and therefore ET and ANPP. Those contrasting trends result in an optimal altitude at about 1400 m a.s.l., where temperature and water availability are optimal in terms of maximum annual ET and ANPP. Our results indicate that

  12. Summary of Terra and Aqua MODIS Long-Term Performance

    NASA Technical Reports Server (NTRS)

    Xiong, Xiaoxiong (Jack); Wenny, Brian N.; Angal, Amit; Barnes, William; Salomonson, Vincent

    2011-01-01

    Since launch in December 1999, the MODIS ProtoFlight Model (PFM) onboard the Terra spacecraft has successfully operated for more than 11 years. Its Flight Model (FM) onboard the Aqua spacecraft, launched in May 2002, has also successfully operated for over 9 years. MODIS observations are made in 36 spectral bands at three nadir spatial resolutions and are calibrated and characterized regularly by a set of on-board calibrators (OBC). Nearly 40 science products, supporting a variety of land, ocean, and atmospheric applications, are continuously derived from the calibrated reflectances and radiances of each MODIS instrument and widely distributed to the world-wide user community. Following an overview of MODIS instrument operation and calibration activities, this paper provides a summary of both Terra and Aqua MODIS long-term performance. Special considerations that are critical to maintaining MODIS data quality and beneficial for future missions are also discussed.

  13. A long-term climate data record of scatterometer winds

    NASA Astrophysics Data System (ADS)

    Belmonte Rivas, Maria; Stoffelen, Ad; Verhoef, Anton; de Kloe, Jos; Verspeek, Jeroen; Vogelzang, Jur

    2015-04-01

    The ocean surface wind stress is a key element of the air-sea interaction, which refers to the transfer of energy, momentum and trace gases between the ocean and the atmosphere, both essential components of the Earth's climate system. We propose to create a global and continuous climate data record (CDR) of ocean stress-equivalent winds from satellite scatterometers from 1991 to present date. This will be done by reprocessing the entire backscatter archives from the ERS1 and ERS2, Quikscat SeaWinds, Metop-A ASCAT and Oceansat-2 OSCAT instruments using publicly available wind retrieval packages and special emphasis on sensor inter-calibration. Along with a consistent long-term record of scatterometer wind stress, this CDR will deliver wind curl/divergence and sea ice extents. This contribution reports on progress made, applications envisioned and current status of this activity.

  14. Long-term Measurements of Nighttime LF Radio Wave Reflection Heights over Central Europe

    NASA Astrophysics Data System (ADS)

    Jacobi, C.; Kürschner, D.

    2005-05-01

    The nighttime ionospheric absolute reflection height of low-frequency (LF) radio waves at oblique incidence has been measured continuously since late 1982 using 1.8kHz sideband phase comparisons between the sky wave and the ground wave of a commercial 177kHz LF transmitter. The dataset allows the analysis of long-term trends and other regular variations of the reflection height. Beside the clear signal of the 11-year solar cycle a quasi-biennial oscillation is visible in LF reflection heights, which is correlated to the equatorial stratospheric wind field. A long-term decreasing reflection height trend is found, confirming results from other measurements and theoretical estimations. The results can be interpreted as a long-term decrease of the height levels of fixed electron density in the lower E region, reflecting a long-term cooling trend of the middle atmosphere.

  15. Scientific Understanding from Long Term Observations: Insights from the Long Term Ecological Research (LTER) Program

    NASA Astrophysics Data System (ADS)

    Gosz, J.

    2001-12-01

    The network dedicated to Long Term Ecological Research (LTER) in the United States has grown to 24 sites since it was formed in 1980. Long-term research and monitoring are performed on parameters thatare basic to all ecosystems and are required to understand patterns, processes, and relationship to change. Collectively, the sites in the LTER Network provide opportunities to contrast marine, coastal, and continental regions, the full range of climatic gradients existing in North America, and aquatic and terrestrial habitats in a range of ecosystem types. The combination of common core areas and long-term research and monitoring in many habitats have allowed unprecedented abilities to understand and compare complex temporal and spatial dynamics associated with issues like climate change, effects of pollution, biodiversity and landuse. For example, McMurdo Dry Valley in the Antarctic has demonstrated an increase in glacier mass since 1993 which coincides with a period of cooler than normal summers and more than average snowfall. In contrast, the Bonanza Creek and Toolik Lake sites in Alaska have recorded a warming period unprecedented in the past 200 years. Nitrogen deposition effects have been identified through long-term watershed studies on biogeochemical cycles, especially at Coweeta Hydrological Lab, Harvard Forest, and the Hubbard Brook Experimental Forest. In aquatic systems, such as the Northern Temperate Lakes site, long-term data revealed time lags in effects of invaders and disturbance on lake communities. Biological recovery from an effect such as lake acidification was shown to lag behind chemical recovery. The long-term changes documented over 2 decades have been instrumental in influencing management practices in many of the LTER areas. In Puerto Rico, the Luquillo LTER demonstrated that dams obstruct migrations of fish and freshwater shrimp and water abstraction at low flows can completely obliterate downstream migration of juveniles and damage

  16. Longleaf pine photosynthetic response to soil resource availability and elevated atmospheric carbon dioxide

    SciTech Connect

    Runion, G.B.; Mitchell, R.J.; Green, T.H.; Prior, S.A.; Rogers, H.H.; Gjerstad, D.H.

    1999-05-01

    Gas exchange responses during a drought cycle were studied in longleaf pine (Pinus palustris Mill.) seedlings after prolonged exposure to varying levels of atmospheric CO{sub 2} soil N and water. Elevated atmospheric CO{sub 2} concentration increased photosynthesis, tended to decrease stomatal conductance, and increased water-use efficiency (WUE). Although soil resource availability influences gas exchange measurements, it generally did not affect the magnitude or direction of the response to CO{sub 2} concentration. However, significant interactions among treatment variables were observed for plant xylem pressure potential. In seedlings grown with high N, a positive growth response to elevated atmospheric CO{sub 2} increased whole-plant water use resulting in more severe plant water stress, despite increased leaf-level WUE; however, under low N conditions the lack of a growth response to elevated CO{sub 2} reduced whole-plant water use, decreased water stress severity, and increased WUE. Photosynthetic response to CO{sub 2} was greatest in the high N treatment at the beginning of the drought cycle, but diminished as water stress increased; however, plants grown with low N showed greater photosynthetic responses to CO{sub 2} later in the drought cycle. Therefore, plant gas exchange rates interact with growth response in determining the severity of water stress under drought and, thus, the ability of elevated atmospheric CO{sub 2} to ameliorate the effects of drought and allow plants to maintain increased rates of photosynthesis may be influenced by the availability of other resources, such as N and water.

  17. Seafloor Weathering As a Long-Term Climate Regulation Mechanism

    NASA Astrophysics Data System (ADS)

    Farahat, N. X.; Abbot, D. S.; Archer, D. E.

    2014-12-01

    The global carbon cycle determines the distribution of carbon between the atmosphere, ocean, and solid earth. Carbon from the mantle enters the Earth's surficial environment as CO2 by volcanic outgassing, and carbon is buried in the oceanic crust as carbonate rocks during silicate rock weathering. The subduction of carbonate-rich oceanic plates returns carbon to the mantle, closing the cycle. Subtle adjustments in continental silicate weathering, widely held to consume atmospheric CO2 at a rate controlled by climate, are believed to have maintained habitable conditions throughout Earth's history. This long term climate regulation mechanism is known as a climate-weathering feedback. Seafloor weathering, low-temperature basalt alteration and carbonate precipitation in the permeable upper oceanic crust, has been proposed as a climate-weathering feedback as well, but the link to climate is presently poorly understood. Such a climate regulation mechanism would be particularly important on waterworld planets where continental silicate weathering cannot regulate climate. It has so far not been possible to determine whether changes in seafloor weathering could contribute to climate regulation on Earth or in a waterworld scenario because the necessary modeling framework has not yet been developed. However, advances in porous media flow modeling and reactive transport modeling, as well as the availability of inexpensive computational power, allow the seafloor weathering problem to be looked at in greater detail. We have developed a spatially resolved two-dimmensional (2D) numerical model of seafloor weathering in the permeable upper oceanic crust. This model simulates 2D off-axis hydrothermal flow coupled to geochemical alteration of seafloor basalt by modeling reactive transport of chemical species in seawater-derived hydrothermal fluids. The focus of this research is to use the model to determine the effect of geological and climatic factors on seafloor weathering, which

  18. Atmospheric mercury inputs in montane soils increase with elevation: evidence from mercury isotope signatures

    PubMed Central

    Zhang, Hua; Yin, Run-sheng; Feng, Xin-bin; Sommar, Jonas; Anderson, Christopher W. N.; Sapkota, Atindra; Fu, Xue-wu; Larssen, Thorjørn

    2013-01-01

    The influence of topography on the biogeochemical cycle of mercury (Hg) has received relatively little attention. Here, we report the measurement of Hg species and their corresponding isotope composition in soil sampled along an elevational gradient transect on Mt. Leigong in subtropical southwestern China. The data are used to explain orography-related effects on the fate and behaviour of Hg species in montane environments. The total- and methyl-Hg concentrations in topsoil samples show a positive correlation with elevation. However, a negative elevation dependence was observed in the mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) signatures of Hg isotopes. Both a MIF (Δ199Hg) binary mixing approach and the traditional inert element method indicate that the content of Hg derived from the atmosphere distinctly increases with altitude. PMID:24270081

  19. Long-term results from an urban CO2 monitoring network

    NASA Astrophysics Data System (ADS)

    Ehleringer, J.; Pataki, D. E.; Lai, C.; Schauer, A.

    2009-12-01

    High-precision atmospheric CO2 has been monitored in several locations through the Salt Lake Valley metropolitan region of northern Utah over the past nine years. Many parts of this semi-arid grassland have transitioned into dense urban forests, supported totally by extensive homeowner irrigation practices. Diurnal changes in fossil-fuel energy uses and photosynthesis-respiration processes have resulted in significant spatial and temporal variations in atmospheric CO2. Here we present an analysis of the long-term patterns and trends in midday and nighttime CO2 values for four sites: a midvalley residential neighborhood, a midvalley non-residential neighborhood, an undeveloped valley-edge area transitioning from agriculture, and a developed valley-edge neighborhood with mixed residential and commercial activities; the neighborhoods span an elevation gradient within the valley of ~100 m. Patterns in CO2 concentrations among neighborhoods were examined relative to each other and relative to the NOAA background station, a desert site in Wendover, Utah. Four specific analyses are considered. First, we present a statistical analysis of weekday versus weekend CO2 patterns in the winter, spring, summer, and fall seasons. Second, we present a statistical analysis of the influences of high-pressure systems on the elevation of atmospheric CO2 above background levels in the winter versus summer seasons. Third, we present an analysis of the nighttime CO2 values through the year, relating these patterns to observed changes in the carbon isotope ratios of atmospheric CO2. Lastly, we examine the rate of increase in midday urban CO2 over time relative to regional and global CO2 averages to determine if the amplification of urban energy use is statistically detectable from atmospheric trace gas measurements over the past decade. These results show two important patterns. First, there is a strong weekday-weekend effect of vehicle emissions in contrast to the temperature

  20. Long term cultivation of larger benthic Foraminifera

    NASA Astrophysics Data System (ADS)

    Wöger, Julia; Eder, Wolfgang; Kinoshita, Shunichi; Antonino, Briguglio; Carles, Ferrandes-Cañadell; Hohenegger, Johann

    2015-04-01

    Benthic Foraminifera are used in a variety of applications employing numerous different methods, i.e. ecological monitoring, studying the effects of ocean acidification, reconstructing palaeo-bathymetry or investigating palaeo-salinity and palaeo-temperature to name only a few. To refine our understanding of ecological influences on larger benthic foraminiferal biology and to review inferences from field observations, culture experiments have become an indispensable tool. While culture experiments on smaller benthic foraminifera have become increasingly frequent in the past century, reports of the cultivation of symbiont bearing larger Foraminifera are rare. Generally, cultivation experiments can be divided into two groups: Culturing of populations and cultivation of single specimens allowing individual investigation. The latter differ form the former by several restrictions resulting from the need to limit individual motility without abridging microenvironmental conditions in the Foraminiferans artificial habitat, necessary to enable the individual to development as unfettered as possible. In this study we present first experiences and preliminary results of the long-term cultivation of larger benthic Foraminifera conducted at the 'Tropical Biosphere Research Station Sesoko Island, University of the Ryukyus', Japan, trying to reproduce natural conditions as closely as possible. Individuals of three species of larger benthic Foraminifera (Heterostegina depressa, Palaeonummulites venosus and Operculina complanata) have been cultured since April 2014. At the time of the general assembly the cultivation experiments will have been going on for more than one year, with the aim to investigate growth rates, longevities and reproduction strategies for comparison with results statistically inferred from application of the of the 'natural laboratory' method. The most important factor influencing foraminiferal health and development was found to be light intensity and light

  1. A new long-term care manifesto.

    PubMed

    Kane, Robert L

    2015-04-01

    This article argues for a fresh look at how we provide long-term care (LTC) for older persons. Essentially, LTC offers a compensatory service that responds to frailty. Policy debate around LTC centers on costs, but we are paying for something we really don't want. Building societal enthusiasm (or even support) for LTC will require re-inventing and re-branding. LTC has three basic components: personal care, housing, and health care (primarily chronic disease management). They can be delivered in a variety of settings. It is rare to find all three done well simultaneously. Personal care (PC) needs to be both competent and compassionate. Housing must provide at least minimal amenities and foster autonomy; when travel time for PC raises costs dramatically, some form of clustered housing may be needed. Health care must be proactive, aimed at preventing exacerbations of chronic disease and resultant hospitalizations. Enhancing preferences means allowing taking informed risks. Payment incentives should reward both quality of care and quality of life, but positive outcomes must be defined as slowing decline. Paying for services but not for housing under Medicaid would automatically level the playing field between nursing homes (NH) and community-based services. Regulations should achieve greater parity between NH and community care and include both positive and negative feedback. Providing post-acute care should be separate from LTC. Using the tripartite LTC framework, we can create innovative flexible approaches to providing needed services for frail older persons in formats that are both desirable and affordable. Such care will be more socially desirable and hence worth paying for. PMID:26035606

  2. Long-term Behavior of DNAPL Residuals

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Illangasekare, T.; Kitanidis, P. K.

    2012-12-01

    Understanding and being able to predict the long-term behavior of DNAPL (i.e., TCE) residuals in the source zone are significant in the evaluation of plume spreading. We apply both theoretical analysis and pore-scale simulations to investigate the mass transfer and the effect of reductive dechlorination, in which the contaminant behaves as electron acceptor. At the upfront of the source zone, where the boundary layer has not fully developed, the mass transfer increases as a power-law function of the Peclet number, and is enhanced by biodegradation. These results are consistent with past findings. Under certain conditions, further downstream inside the source zone, the rate of dissolution is slower due to the diluted mass from upstream. Widely applied first-order biodegradation implicitly assumes that the reaction solely depends on the concentration of the contaminant. However, in the slow dilution region, the limitation of electron donor on biodegradation is not negligible. For the reaction between an electron donor and an electron acceptor with intrinsic second-order kinetics, the late-time bio-reaction demonstrates a first-order decay macroscopically with respect to the mass of electron donor, not with respect to that of the contaminant. The late-time decay rate only depends on the intrinsic rate and the solubility of the contaminant. During the intermediate time, affecting by both the concentrations of electron donor and electron acceptor, the first-order decay is not valid. We show that the electron donor decays as exp(-t^2), instead of exp(-t). Moreover, the intermediate-time decay rate is a function of the spatial distribution of DNAPL residuals and the initial conditions.he relationship of the Sherwood number and Peclet number (Comparison of pore-scale simulations and best-fitting curve) he decay of electron donor as a function of t^2

  3. LONG TERM IN SITU DISPOSAL ENGINEERING STUDY

    SciTech Connect

    ADAMS; CARLSON; BROCKMAN

    2003-07-23

    Patent application pulled per Ken Norris (FH General Counsel). The objective of this study is to devise methods, produce conceptual designs, examine and select alternatives, and estimate costs for the demonstration of long-term (300-year) in situ disposal of an existing waste disposal site. The demonstration site selected is the 216-A-24 Crib near the 200 East Area. The site contains a fission product inventory and has experienced plant, animal, and inadvertent than intrusion. Of the potential intrusive events and transport pathways at the site, potential human intrusion has been given primary consideration in barrier design. Intrusion by wind, plants, and animals has been given secondary consideration. Groundwater modeling for a number of barrier configurations has been carried out to help select a barrier that will minimize water infiltration and waste/water contact time. The estimated effective lifetime and cost of 20 barrier schemes, using a variety of materials, have been evaluated. The schemes studied include single component surface barriers, multicomponent barriers, and massively injected grout barriers. Five barriers with high estimated effective lifetimes and relatively low costs have been selected for detailed evaluation. They are basalt riprap barriers, massive soil barriers, salt basin barriers, multi-component fine/coarse barriers, and cemented basalt barriers. A variety of materials and configurations for marking the site have also been considered. A decision analysis was completed to select a barrier scheme for demonstration. The analysis indicated that the basalt riprap alternative would be the preferred choice for a full-scale demonstration. The recommended approach is to demonstrate the basalt riprap barrier at the 216-A-24 Crib as soon as possible. Methods and costs of assessing effectiveness of the demonstration are also described. Preliminary design modifications and costs for applying the five selected barrier schemes to other site types are

  4. Modeling Maintenance of Long-Term Potentiation in Clustered Synapses: Long-Term Memory without Bistability

    PubMed Central

    Smolen, Paul

    2015-01-01

    Memories are stored, at least partly, as patterns of strong synapses. Given molecular turnover, how can synapses maintain strong for the years that memories can persist? Some models postulate that biochemical bistability maintains strong synapses. However, bistability should give a bimodal distribution of synaptic strength or weight, whereas current data show unimodal distributions for weights and for a correlated variable, dendritic spine volume. Thus it is important for models to simulate both unimodal distributions and long-term memory persistence. Here a model is developed that connects ongoing, competing processes of synaptic growth and weakening to stochastic processes of receptor insertion and removal in dendritic spines. The model simulates long-term (>1 yr) persistence of groups of strong synapses. A unimodal weight distribution results. For stability of this distribution it proved essential to incorporate resource competition between synapses organized into small clusters. With competition, these clusters are stable for years. These simulations concur with recent data to support the “clustered plasticity hypothesis” which suggests clusters, rather than single synaptic contacts, may be a fundamental unit for storage of long-term memory. The model makes empirical predictions and may provide a framework to investigate mechanisms maintaining the balance between synaptic plasticity and stability of memory. PMID:25945261

  5. Subalpine Forest Carbon Cycling Short- and Long-Term Influence ofClimate and Species

    SciTech Connect

    Kueppers, L.; Harte, J.

    2005-08-23

    Ecosystem carbon cycle feedbacks to climate change comprise one of the largest remaining sources of uncertainty in global model predictions of future climate. Both direct climate effects on carbon cycling and indirect effects via climate-induced shifts in species composition may alter ecosystem carbon balance over the long term. In the short term, climate effects on carbon cycling may be mediated by ecosystem species composition. We used an elevational climate and tree species composition gradient in Rocky Mountain subalpine forest to quantify the sensitivity of all major ecosystem carbon stocks and fluxes to these factors. The climate sensitivities of carbon fluxes were species-specific in the cases of relative above ground productivity and litter decomposition, whereas the climate sensitivity of dead wood decay did not differ between species, and total annual soil CO2 flux showed no strong climate trend. Lodge pole pine relative productivity increased with warmer temperatures and earlier snowmelt, while Engelmann spruce relative productivity was insensitive to climate variables. Engelmann spruce needle decomposition decreased linearly with increasing temperature(decreasing litter moisture), while lodgepole pine and subalpine fir needle decay showed a hump-shaped temperature response. We also found that total ecosystem carbon declined by 50 percent with a 2.88C increase in mean annual temperature and a concurrent 63 percent decrease ingrowing season soil moisture, primarily due to large declines in mineral soil and dead wood carbon. We detected no independent effect of species composition on ecosystem C stocks. Overall, our carbon flux results suggest that, in the short term, any change in subalpine forest net carbon balance will depend on the specific climate scenario and spatial distribution of tree species. Over the long term, our carbon stock results suggest that with regional warming and drying, Rocky Mountain subalpine forest will be a net source of carbon

  6. Research on Long-Term Orbit Propagation for Space Debris in LEO

    NASA Astrophysics Data System (ADS)

    Peng, Keke; Pang, Baojun; Xiao, Weike

    2013-08-01

    Space debris long-term orbit propagation is one of the main problems for the space debris environment models. The evolution of space debris in low Earth orbit (LEO) is determined by a complex interplay of different perturbations. The aim of this paper is to investigate the long-term effects of the most dominating perturbations: Earth geopotential effects, atmospheric drag, luni-solar perturbations and solar radiation pressure. The atmospheric drag is the major non-gravitational perturbation in LEO. This article provides an average method of numerical integration on one revolution for rotating and stationary atmosphere, and then one can make use of various atmospheric densities to calculate the orbital evolution. Using this method, we have analyzed the effects of rotating and stationary atmospheric drag perturbation on orbital lifetime. The results show the effects of solar activity and geomagnetic index on orbital evolution are obvious. The lifetime difference in rotating atmosphere is mostly depending on inclinations of space debris.

  7. Soil respiration in northern forests exposed to elevated atmospheric carbon dioxide and ozone.

    PubMed

    Pregitzer, Kurt; Loya, Wendy; Kubiske, Mark; Zak, Donald

    2006-06-01

    The aspen free-air CO2 and O3 enrichment (FACTS II-FACE) study in Rhinelander, Wisconsin, USA, is designed to understand the mechanisms by which young northern deciduous forest ecosystems respond to elevated atmospheric carbon dioxide (CO2) and elevated tropospheric ozone (O3) in a replicated, factorial, field experiment. Soil respiration is the second largest flux of carbon (C) in these ecosystems, and the objective of this study was to understand how soil respiration responded to the experimental treatments as these fast-growing stands of pure aspen and birch + aspen approached maximum leaf area. Rates of soil respiration were typically lowest in the elevated O3 treatment. Elevated CO2 significantly stimulated soil respiration (8-26%) compared to the control treatment in both community types over all three growing seasons. In years 6-7 of the experiment, the greatest rates of soil respiration occurred in the interaction treatment (CO2 + O3), and rates of soil respiration were 15-25% greater in this treatment than in the elevated CO2 treatment, depending on year and community type. Two of the treatments, elevated CO2 and elevated CO2 + O3, were fumigated with 13C-depleted CO2, and in these two treatments we used standard isotope mixing models to understand the proportions of new and old C in soil respiration. During the peak of the growing season, C fixed since the initiation of the experiment in 1998 (new C) accounted for 60-80% of total soil respiration. The isotope measurements independently confirmed that more new C was respired from the interaction treatment compared to the elevated CO2 treatment. A period of low soil moisture late in the 2003 growing season resulted in soil respiration with an isotopic signature 4-6 per thousand enriched in 13C compared to sample dates when the percentage soil moisture was higher. In 2004, an extended period of low soil moisture during August and early September, punctuated by a significant rainfall event, resulted in soil

  8. Long-term macronutrient stoichiometry of UK ombrotrophic peatlands

    NASA Astrophysics Data System (ADS)

    Schillereff, Daniel; Boyle, John; Toberman, Hannah; Adams, Jessica; Tipping, Ed

    2016-04-01

    Ombrotrophic peatlands across northern latitudes represent a globally-important store for carbon (C), nitrogen (N) and phosphorus (P) through the Holocene. A key characteristic of ombrotrophic bogs is that N, P and other elements vital to their biogeochemical functioning are almost exclusively supplied by hydrological and biological inputs from the atmosphere. While different mechanisms regulating the atmospheric supply of N and P and their limiting effects on bog productivity have been widely studied, limited attention has been paid to the long-term patterns of, and controls on, macronutrient accumulation, cycling and stoichiometry in ombrotrophic peatlands. Indeed there is a dearth of C, N and P stoichiometric data from the UK despite decades of peatland research. Using data from 15 sites, we report the first estimates of millennial-scale macronutrient concentrations and accumulation rates in UK ombrotrophic peats. Carbon, nitrogen and phosphorus concentrations were measured on cores from five ombrotrophic blanket mires, spanning 4000-10000 years to present, and integrated with existing nutrient profiles from ten Scottish sites. Long-term C, N and P concentrations for the UK are 55.1, 1.55 and 0.037 wt%, similar to the few existing northern and tropical comparable sites worldwide. The uppermost peat (0 - 0.2 m) is more enriched in P and N (51.0, 1.86, and 0.070 wt%), while the deeper peat (0.5 - 1.25 m) is more depleted (56.6, 1.39, and 0.028 wt%). Long-term average (whole core) accumulation rates of carbon, nitrogen and phosphorus are 25.3±2.2 gC m‑2 yr‑1, 0.70±0.09 gN m‑2 yr‑1 and 0.018±0.004 gP m‑2 yr‑1, again similar to values reported elsewhere in the world. A number of significant findings can be drawn from our results: i) N and P concentrations in ombrotrophic peat are strongly associated, such that a regression model of N concentration on P concentration and mean annual precipitation, based on global meta data for surface peat samples, can

  9. Phytochemical changes in leaves of subtropical grasses and fynbos shrubs at elevated atmospheric CO 2 concentrations

    NASA Astrophysics Data System (ADS)

    Hattas, D.; Stock, W. D.; Mabusela, W. T.; Green, I. R.

    2005-07-01

    The effects of elevated atmospheric CO 2 concentrations on plant polyphenolic, tannin, nitrogen, phosphorus and total nonstructural carbohydrate concentrations were investigated in leaves of subtropical grass and fynbos shrub species. The hypothesis tested was that carbon-based secondary compounds would increase when carbon gain is in excess of growth requirements. This premise was tested in two ecosystems involving plants with different photosynthetic mechanisms and growth strategies. The first ecosystem comprised grasses from a C 4-dominated, subtropical grassland, where three plots were subjected to three different free air CO 2 enrichment treatments, i.e., elevated (600 to 800 μmol mol -1), intermediate (400 μmol mol -1) and ambient atmospheric CO 2. One of the seven grass species, Alloteropsis semialata, had a C 3 photosynthetic pathway while the other grasses were all C 4. The second ecosystem was simulated in a microcosm experiment where three fynbos species were grown in open-top chambers at ambient and 700 μmol mol -1 atmospheric CO 2 in low nutrient acid sands typical of south western coastal and mountain fynbos ecosystems. Results showed that polyphenolics and tannins did not increase in the grass species under elevated CO 2 and only in Leucadendron laureolum among the fynbos species. Similarly, foliar nitrogen content of grasses was largely unaffected by elevated CO 2, and among the fynbos species, only L. laureolum and Leucadendron xanthoconus showed changes in foliar nitrogen content under elevated CO 2, but these were of different magnitude. The overall decrease in nitrogen and phosphorus and consequent increase in C:N and C:P ratio in both ecosystems, along with the increase in polyphenolics and tannins in L. laureolum in the fynbos ecosystem, may negatively affect forage quality and decomposition rates. It is concluded that fast growing grasses do not experience sink limitation and invest extra carbon into growth rather than polyphenolics and

  10. Are microbial N transformation rates in a permanent grassland soil after 17 years of elevated atmospheric CO2 sensitive to soil temperature?

    NASA Astrophysics Data System (ADS)

    Moser, Gerald; Gorenflo, André; Brenzinger, Kristof; Clough, Tim; Braker, Gesche; Müller, Christoph

    2016-04-01

    Long-term observations (17 years) within the Giessen Free Air Carbon dioxide Enrichment (Giessen FACE) study on permanent grassland showed that the carbon fertilization caused significant changes in the ecosystem nitrogen cycle. These changes are responsible for a doubling of annual N2O emissions under elevated atmospheric CO2 (eCO2) caused by increased emissions during the plant growing season. The goal of this lab study was to understand how soil temperature influences the long-term effects of eCO2 and plant carbon input on microbial N transformations in the Giessen FACE. Therefore, a pulse labelling study with 15N tracing of 15NH4+ and 15NO3‑ was carried out with incubated soil samples from elevated and ambient CO2 FACE rings in climate chambers at two different temperatures (10°C and 19°C), while water filled pore space of the samples was adjusted to the same level. The various N pools in the soil (NH4+, NO3‑, NO2‑, soil organic matter), N2O emissions and simultaneous gross N transformation rates were quantified. The quantification of the gross N transformations are based on the turnover of 15NH4+, 15NO3‑, 15NO2‑ and shall illuminate the interaction between carbon fertilization, temperature and changes in nitrogen cycle in this grassland soil. While the soil respiration after labelling was significantly increased at 19°C compared to 10°C, N2O emissions showed no significant differences. There were also no significant differences of N2O emissions between soil samples from control and elevated CO2 rings within each temperature level. As the soil temperature (within the range of 10-19°C) had no significant effects on N transformations responsible for the observed doubling of N2O emissions under eCO2, it seems most likely that other factors like direct carbon input by plants and/or soil moisture differences between ambient and elevated rings in the field are responsible for the observed increase in N2O emissions under eCO2.

  11. Long term vegetation change in California Park: Evidence for alternate states?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding shifts in ecosystem state is a frontier in ecology with important implications for land management and human well-being. The goals of this study are 1) to describe long-term vegetation change in a high-elevation sagebrush steppe park (California Park, Colorado) and 2) evaluate evidenc...

  12. Long-Term Space Astrophysics Program

    NASA Technical Reports Server (NTRS)

    Nowark, Michael A.

    2001-01-01

    This is the final report for our Long-Term Space Astrophysics Program (NRA 94-OSS-12) grant NAG 5-3225. The proposal is entitled 'Spectral and Temporal Properties of Black Hole Candidates', and began funding in May 1995, and ran through 31 Aug 2000. The project summary from the original proposal was as follows: 'We will study the spectral and temporal properties of black hole candidates (BHC) by using data from archival sources (e.g., EXOSAT, Ginga, ROSAT) and proposed follow-up observations with modern instruments (e.g., ASCA, XTE). Our spectral studies will focus on identifying the basic characteristics and luminosities of the emission components in the various 'states' of BHC. We hope to understand and quantify the global energetics of these states. Our temporal studies will focus on expanding and classifying our knowledge of BHC variability properties in each state. We will explore the nature of quasi-periodic oscillations in BHC. We will combine our spectral and temporal studies by analyzing time lags and variability coherence between energy channels. In addition, we will investigate ways of correlating observed variability behavior with specific emission components.' We have accomplished many of these goals laid out within the original proposal. As originally proposed, we have utilized both archival and proprietary satellite data. In terms of archival data, we have utilized data from the Advanced Satellite for Cosmology and Astrophysics (ASCA), ROSAT, and the Rossi X-ray Timing Explorer (RXTE). We also obtained proprietary data from ASCA, RXTE, and the Extreme Ultraviolet Explorer (EUVE). In terms of sources, we have examined a wide variety of both galactic black hole candidates and extra-galactic black holes. For the galactic black holes we have observed and analyzed both the low/hard state and the high/soft state. We have performed both spectral and timing analyses on all of these objects. In addition, we have also examined a number of neutron stars or

  13. Long term property prediction of polyethylene nanocomposites

    NASA Astrophysics Data System (ADS)

    Shaito, Ali Al-Abed

    properties of the nanocomposites was analyzed by examining tensile and creep-recovery behavior of the films at temperatures in the range of 25 to -100°C. Within the measured temperature range, the materials showed a nonlinear temperature dependent response. The time-temperature superposition principle was successfully used to predict the long term behavior of LLDPE nanocomposites.

  14. LOP- LONG-TERM ORBIT PREDICTOR

    NASA Technical Reports Server (NTRS)

    Kwok, J. H.

    1994-01-01

    The Long-Term Orbit Predictor (LOP) trajectory propagation program is a useful tool in lifetime analysis of orbiting spacecraft. LOP is suitable for studying planetary orbit missions with reconnaissance (flyby) and exploratory (mapping) trajectories. Sample data is included for a geosynchronous station drift cycle study, a Venus radar mapping strategy, a frozen orbit about Mars, and a repeat ground trace orbit. LOP uses the variation-of-parameters method in formulating the equations of motion. Terms involving the mean anomaly are removed from numerical integrations so that large step sizes, on the order of days, are possible. Consequently, LOP executes much faster than programs based on Cowell's method, such as the companion program ASAP (the Artificial Satellite Analysis Program, NPO-17522, also available through COSMIC). The program uses a force model with a gravity field of up to 21 by 21, lunisolar perturbation, drag, and solar radiation pressure. The input includes classical orbital elements (either mean or oscillating), orbital elements of the sun relative to the planet, reference time and dates, drag coefficients, gravitational constants, planet radius, rotation rate. The printed output contains the classical elements for each time step or event step, and additional orbital data such as true anomaly, eccentric anomaly, latitude, longitude, periapsis altitude, and the rate of change per day of certain elements. Selected output is additionally written to a plot file for postprocessing by the user. LOP is written in FORTRAN 77 for batch execution on IBM PC compatibles running MS-DOS with a minimum of 256K RAM. Recompiling the source requires the Lahey F77 v2.2 compiler. The LOP package includes examples that use LOTUS 1-2-3 for graphical displays, but any graphics software package should be able to handle the ASCII plot file. The program is available on two 5.25 inch 360K MS-DOS format diskettes. The program was written in 1986 and last updated in 1989. LOP is

  15. Long term prognosis of reactive salmonella arthritis

    PubMed Central

    Leirisalo-Repo, M; Helenius, P; Hannu, T; Lehtinen, A; Kreula, J; Taavitsainen, M; Koskimies, S

    1997-01-01

    OBJECTIVES—Reactive joint complications triggered by salmonella gastroenteritis are increasingly reported, but the outcome and long term prognosis of the patients is incompletely known. This study looked at the prognosis of salmonella arthritis in patients hospitalised in 1970-1986.
METHODS—Hospital records from two hospitals in southern Finland were screened for patients with the discharge diagnosis of salmonellosis or reactive, postinfectious arthritis or Reiter's disease. For the patients with confirmed diagnosis of reactive salmonella arthritis, data about the acute disease were collected from the hospital records. A follow up study was performed.
RESULTS—There were 63 patients (28 women, 35 men, mean age 36.5 years) with salmonella arthritis. Urethritis occurred in 27%, eye inflammation in 13%, and low back pain in 44% of the patients. HLA-B27 was present in 88%. More men than women were HLA-B27 positive. HLA-B27 positive patients had higher erythrocyte sedimentation rate (mean 80.9 v 46.5 mm 1st h, p = 0.0180). Also, extra-articular features and radiological sacroiliitis were seen only in HLA-B27 positive patients. A follow up study was performed on 50 patients mean 11.0 (range 5-22 years) later. Twenty patients had recovered completely. Ten patients had mild joint symptoms, 11 patients had had a new acute transient arthritis, and five acute iritis. Eight patients had developed chronic spondyloarthropathy. Radiological sacroiliitis was seen in six of 44 patients, more frequently in male than in female patients (32% v 0%; p = 0.0289). Recurrent or chronic arthritis, iritis or radiological sacroiliitis developed only in HLA-B27 positive patients.
CONCLUSION—Joint symptoms are common after reactive salmonella arthritis. HLA-B27 contributes to the severity of acute disease and to the late prognosis.

 PMID:9370874

  16. Long-term observations of tropospheric ozone: GAW Measurement Guidelines

    NASA Astrophysics Data System (ADS)

    Tarasova, Oksana; Galbally, Ian E.; Schultz, Martin G.

    2013-04-01

    The Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO) coordinates long-term observations of the chemical composition and physical properties of the atmosphere which are relevant for understanding of atmospheric chemistry and climate change. Atmospheric observations of reactive gases (tropospheric ozone, carbon monoxide, volatile organic compounds and nitrogen oxides) coordinated by the GAW Programme complement local and regional scale air quality monitoring efforts. As part of the GAW quality assurance (QA) system detailed measurement guidelines for atmospheric trace species are developed by international expert teams at irregular intervals. The most recent report focuses on continuous in-situ measurements of ozone in the troposphere, performed in particular at continental or island sites with altitudes ranging from sea level to mountain tops. Data Quality Objectives (DQOs) are defined for different applications of the data (e.g. trend analysis and verification of global model forecasts). These DQOs include a thorough discussion of the tolerable level of measurement uncertainty and data completeness. The guidelines present the best practices and practical arrangements adopted by the GAW Programme in order to enable the GAW station network to approach or achieve the defined tropospheric ozone DQOs. The document includes information on the selection of station and measurement locations, required skills and training of staff, recommendations on the measurement technique and the necessary equipment to perform highest quality measurements, rules for conducting the measurements, preparing the data and archiving them, and more. Much emphasis is given to discussions about how to ensure the quality of the data through tracing calibrations back to primary standards, proper calibration and data analysis, etc. In the GAW Programme the QA system is implemented through Central Facilities (Central Calibration Laboratories, World and Regional

  17. Nitrogen-mediated effects of elevated CO2 on intra-aggregate soil pore structure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    While previous elevated atmospheric CO2 research has addressed changes in belowground processes, its effects on soil structure remain virtually undescribed. This study examined the long-term effects of elevated CO2 and N fertilization on soil structural changes in a bahiagrass pasture grown on a san...

  18. Long-term evolution is surprisingly predictable in lattice proteins

    PubMed Central

    Palmer, Michael E.; Moudgil, Arnav; Feldman, Marcus W.

    2013-01-01

    It has long been debated whether natural selection acts primarily upon individual organisms, or whether it also commonly acts upon higher-level entities such as lineages. Two arguments against the effectiveness of long-term selection on lineages have been (i) that long-term evolutionary outcomes will not be sufficiently predictable to support a meaningful long-term fitness and (ii) that short-term selection on organisms will almost always overpower long-term selection. Here, we use a computational model of protein folding and binding called ‘lattice proteins’. We quantify the long-term evolutionary success of lineages with two metrics called the k-fitness and k-survivability. We show that long-term outcomes are surprisingly predictable in this model: only a small fraction of the possible outcomes are ever realized in multiple replicates. Furthermore, the long-term fitness of a lineage depends only partly on its short-term fitness; other factors are also important, including the ‘evolvability’ of a lineage—its capacity to produce adaptive variation. In a system with a distinct short-term and long-term fitness, evolution need not be ‘short-sighted’: lineages may be selected for their long-term properties, sometimes in opposition to short-term selection. Similar evolutionary basins of attraction have been observed in vivo, suggesting that natural biological lineages will also have a predictive long-term fitness. PMID:23466559

  19. Potential Effects of Elevated Atmospheric Carbon Dioxide (CO2) on Coastal Wetlands

    USGS Publications Warehouse

    McKee, Karen

    2006-01-01

    Carbon dioxide (CO2) concentration in the atmosphere has steadily increased from 280 parts per million (ppm) in preindustrial times to 381 ppm today and is predicted by some models to double within the next century. Some of the important pathways whereby changes in atmospheric CO2 may impact coastal wetlands include changes in temperature, rainfall, and hurricane intensity (fig. 1). Increases in CO2 can contribute to global warming, which may (1) accelerate sea-level rise through melting of polar ice fields and steric expansion of oceans, (2) alter rainfall patterns and salinity regimes, and (3) change the intensity and frequency of tropical storms and hurricanes. Sea-level rise combined with changes in storm activity may affect erosion and sedimentation rates and patterns in coastal wetlands and maintenance of soil elevations. Feedback loops between plant growth and hydroedaphic conditions also contribute to maintenance of marsh elevations through accumulation of organic matter. Although increasing CO2 concentration may contribute to global warming and climate changes, it may also have a direct impact on plant growth and development by stimulating photosynthesis or improving water use efficiency. Scientists with the U.S. Geological Survey are examining responses of wetland plants to elevated CO2 concentration and other factors. This research will lead to a better understanding of future changes in marsh species composition, successional rates and patterns, ecological functioning, and vulnerability to sea-level rise and other global change factors.

  20. The effects of elevation data representation on mesoscale atmospheric model simulations

    SciTech Connect

    Walker, H.; Leone, J.M. Jr.; Kim, Jinwon

    1996-01-01

    Mesoscale atmospheric model simulations rely on descriptions of the land surface characteristics, which must be developed from geographic databases. Certain features of the geographic data, such as its resolution and accuracy, as well as the method of processing for use in the model, can be very important in producing accurate model simulations. The work described here is part of research effort into the relationship between these aspects of geographic data and the performance of mesoscale atmospheric models and is particularly focused on elevation data and how it is prepared for use in such models. A source for digital elevation data will typically not be at the resolution required for a given model simulation and so a resampling step is required. In addition, predictive non-linear model often cannot accept forcing at high spatial frequencies due to the terrain, thus smoothing is also required. The effect of different means of resampling and smoothing elevation data on two types of model simulations is investigated. At smaller spatial scales, nocturnal drainage winds in mountain valleys in Colorado are examined for effects on the general characteristics as well as the details of the flows. At the larger end of the mesoscale, extended simulations of California weather are examined for effects on orographic lifting, low-level convergence and divergence and ultimately rain and snow distribution.

  1. Habitable Planets: Interior Dynamics and Long-Term Evolution

    NASA Astrophysics Data System (ADS)

    Tackley, Paul J.; Ammann, Michael M.; Brodholt, John P.; Dobson, David P.; Valencia, Diana

    2014-04-01

    Here, the state of our knowledge regarding the interior dynamics and evolution of habitable terrestrial planets including Earth and super-Earths is reviewed, and illustrated using state-of-the-art numerical models. Convection of the rocky mantle is the key process that drives the evolution of the interior: it causes plate tectonics, controls heat loss from the metallic core (which generates the magnetic field) and drives long-term volatile cycling between the atmosphere/ocean and interior. Geoscientists have been studying the dynamics and evolution of Earth's interior since the discovery of plate tectonics in the late 1960s and on many topics our understanding is very good, yet many first-order questions remain. It is commonly thought that plate tectonics is necessary for planetary habitability because of its role in long-term volatile cycles that regulate the surface environment. Plate tectonics is the surface manifestation of convection in the 2900-km deep rocky mantle, yet exactly how plate tectonics arises is still quite uncertain; other terrestrial planets like Venus and Mars instead have a stagnant lithosphere- essentially a single plate covering the entire planet. Nevertheless, simple scalings as well as more complex models indicate that plate tectonics should be easier on larger planets (super-Earths), other things being equal. The dynamics of terrestrial planets, both their surface tectonics and deep mantle dynamics, change over billions of years as a planet cools. Partial melting is a key process influencing solid planet evolution. Due to the very high pressure inside super-Earths' mantles the viscosity would normally be expected to be very high, as is also indicated by our density function theory (DFT) calculations. Feedback between internal heating, temperature and viscosity leads to a superadiabatic temperature profile and self-regulation of the mantle viscosity such that sluggish convection still occurs.

  2. Elevated atmospheric CO 2 concentration and temperature across an urban-rural transect

    NASA Astrophysics Data System (ADS)

    George, K.; Ziska, L. H.; Bunce, J. A.; Quebedeaux, B.

    The heat island effect and the high use of fossil fuels in large city centers are well documented, but by how much fossil fuel consumption is elevating atmospheric CO 2 concentrations and whether elevations in both atmospheric CO 2 and air temperature from rural to urban areas are consistently different from year to year are less well known. Our aim was to record atmospheric CO 2 concentrations, air temperature and other environmental variables in an urban area and compare it to suburban and rural sites to see if urban sites are experiencing climates expected globally in the future with climate change. A transect was established from Baltimore city center (Urban site), to the outer suburbs of Baltimore (suburban site) and out to an organic farm (rural site). At each site a weather station was set-up to monitor environmental variables for 5 years. Atmospheric CO 2 was consistently and significantly increased on average by 66 ppm from the rural to the urban site over the 5 years of the study. Air temperature was also consistently and significantly higher at the urban site (14.8 °C) compared to the suburban (13.6 °C) and rural (12.7 °C) sites. Relative humidity was not different between sites whereas the vapor pressure deficit (VPD) was significantly higher at the urban site compared to the suburban and rural sites. An increase in nitrogen deposition at the rural site of 0.6% and 1.0% compared to the suburban and urban sites was small enough not to affect soil nitrogen content. Dense urban areas with large populations and high vehicular traffic have significantly different microclimates compared to outlying suburban and rural areas. The increases in atmospheric CO 2 and air temperature are similar to changes predicted in the short term with global climate change, therefore providing an environment suitable for studying future effects of climate change on terrestrial ecosystems.

  3. Mineral nutrition and plant responses to elevated levels of atmospheric CO{sub 2}

    SciTech Connect

    Ahluwalia, A.

    1996-08-01

    The atmospheric concentration of CO{sub 2}, a radiatively-active ({open_quotes}green-house{close_quotes}) gas, is increasing. This increase is considered a post-industrial phenomenon attributable to increasing rates of fossil fuel combustion and changing land use practices, particularly deforestation. Climate changes resulting from such elevated atmospheric CO{sub 2} levels, in addition to the direct effects of increased CO{sub 2}, are expected to modify the productivity of forests and alter species distributions. Elevated levels of CO{sub 2} have been shown, in some cases, to lead to enhanced growth rates in plants, particularly those with C{sub 3} metabolism - indicating that plant growth is CO{sub 2}-limited in these situations. Since the major process underlying growth is CO{sub 2} assimilation via photosynthesis in leaves, plant growth represents a potential for sequestering atmospheric carbon into biomass, but this potential could be hampered by plant carbon sink size. Carbon sinks are utilization sites for assimilated carbon, enabling carbon assimilation to proceed without potential inhibition from the accumulation of assimilate (photosynthate). Plant growth provides new sinks for assimilated carbon which permits greater uptake of atmospheric carbon dioxide. However, sinks are, on the whole, reduced in size by stress events due to the adverse effects of stress on photosynthetic rates and therefore growth. This document reviews some of the literature on plant responses to increasing levels of atmospheric carbon dioxide and to inadequate nutrient supply rates, and with this background, the potential for nutrient-limited plants to respond to increasing carbon dioxide is addressed. Conclusions from the literature review are then tested experimentally by means of a case study exploring carbon-nitrogen interactions in seedlings of loblolly pine.

  4. Elevated atmospheric CO2 alters the arthropod community in a forest understory

    NASA Astrophysics Data System (ADS)

    Hamilton, Jason; Zangerl, Arthur R.; Berenbaum, May R.; Sparks, Jed P.; Elich, Lauren; Eisenstein, Alissa; DeLucia, Evan H.

    2012-08-01

    The objective of this study was to determine the extent to which overall population sizes and community composition of arthropods in a naturally occurring forest understory are altered by elevated CO2. The Free Air Concentration Enrichment (FACE) method was used to fumigate large, replicated plots in the Piedmont region of North Carolina, USA to achieve the CO2 concentration predicted for 2050 (˜580 μl l-1). In addition, the extent to which unrestricted herbivorous arthropods were spatially delimited in their resource acquisition was determined. Stable isotope data for spiders (δ13C and δ15N) were collected in ambient and elevated CO2 plots and analyzed to determine whether their prey species moved among plots. Elevated CO2 had no effect on total arthropod numbers but had a large effect on the composition of the arthropod community. Insects collected in our samples were identified to a level that allowed for an assignment of trophic classification (generally to family). For the groups of insects sensitive to atmospheric gas composition, there was an increase in the numbers of individuals collected in primarily predaceous orders (Araneae and Hymenoptera; from 60% to more than 150%) under elevated CO2 and a decrease in the numbers in primarily herbivorous orders (Lepidoptera and Coleoptera; from -30 to -45%). Isotopic data gave no indication that the treatment plots represented a "boundary" to the movement of insects or that there were distinct and independent insect populations inside and outside the treatment plots. A simple two-ended mixing model estimates 55% of the carbon and nitrogen in spider biomass originated external to the elevated CO2 plots. In addition to changes in insect performance, decreases in herbivorous arthropods and increases in predaceous arthropods may also be factors involved in reduced herbivory under elevated CO2 in this forest.

  5. Effects of elevated atmospheric carbon dioxide and temperature on soil respiration in Douglas fir seedling systems

    SciTech Connect

    Lin, G.; Ehleringer, J.R.; Rygiewicz, P.T.

    1995-06-01

    We investigated the effect of CO{sub 2} enrichment and temperature increase on root respiration, litter decomposition, consumption of soil organic matter, and overall soil respiration. Douglas fir (Pseudotsuga menziesii) seedlings were being grown in the US EPA global climate change facility in Corvallis at two atmospheric CO{sub 2} concentrations and two temperatures. Soil-respired CO{sub 2} was collected for carbon and oxygen isotope analysis. Litter and new roots were also collected for carbon isotope analyses, and litter and root water were collected for oxygen isotope analyses. Isotope data were used to distinguish the sources of CO{sub 2} between root respiration, litter decomposition, and consumption of soil organic matter. Our results indicated that elevated CO{sub 2} and temperature increased soil respiration, and there was an interaction between CO{sub 2} and temperature. Elevated temperature increased only litter decomposition rate at ambient CO{sub 2}, but both root respiration and litter decomposition at elevated CO{sub 2}. Consumption of soil organic matter was a significant source for soil-respired CO{sub 2}, especially at elevated CO{sub 2}.

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

    PubMed

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

    2015-12-17

    The negative effect of increasing atmospheric nitrogen (N) pollution on grassland biodiversity is now incontrovertible. However, the recent introduction of cleaner technologies in the UK has led to reductions in the emissions of nitrogen oxides, with concomitant decreases in N deposition. The degree to which grassland biodiversity can be expected to 'bounce back' in response to these improvements in air quality is uncertain, with a suggestion that long-term chronic N addition may lead to an alternative low biodiversity state. Here we present evidence from the 160-year-old Park Grass Experiment at Rothamsted Research, UK, that shows a positive response of biodiversity to reducing N addition from either atmospheric pollution or fertilizers. The proportion of legumes, species richness and diversity increased across the experiment between 1991 and 2012 as both wet and dry N deposition declined. Plots that stopped receiving inorganic N fertilizer in 1989 recovered much of the diversity that had been lost, especially if limed. There was no evidence that chronic N addition has resulted in an alternative low biodiversity state on the Park Grass plots, except where there has been extreme acidification, although it is likely that the recovery of plant communities has been facilitated by the twice-yearly mowing and removal of biomass. This may also explain why a comparable response of plant communities to reduced N inputs has yet to be observed in the wider landscape. PMID:26633635

  7. The long-term legacy of fossil fuels

    NASA Astrophysics Data System (ADS)

    Tyrrell, Toby; Shepherd, John G.; Castle, Stephanie

    2007-09-01

    Fossil fuels will have large impacts on ocean chemistry and climate during the period while they are being burnt (and carbon dioxide emitted) in large amounts. It is frequently assumed that these impacts will fade away soon thereafter. Recent model results, by contrast, suggest that significant impacts will persist for hundreds of thousands of years after emissions cease. We present a new analysis that supports these model findings by elucidating the cause of this `fossil fuel hangover' phenomenon. We explain why the carbonate compensation feedback is atypical, compared to other feedbacks, in the sense that convergence is back towards a new steady-state that is distinct from the starting state. We also calculate in greater detail the predicted implications for the future ocean and atmosphere. The post-fossil fuel long-term equilibrium state could differ from the pre-anthropogenic state by as much as 50% for total dissolved inorganic carbon and alkalinity and 100% for atmospheric pCO2, depending on the total amount of future emissions.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  9. Stochastic Induction of Long-Term Potentiation and Long-Term Depression.

    PubMed

    Antunes, G; Roque, A C; Simoes-de-Souza, F M

    2016-01-01

    Long-term depression (LTD) and long-term potentiation (LTP) of granule-Purkinje cell synapses are persistent synaptic alterations induced by high and low rises of the intracellular calcium ion concentration ([Ca(2+)]), respectively. The occurrence of LTD involves the activation of a positive feedback loop formed by protein kinase C, phospholipase A2, and the extracellular signal-regulated protein kinase pathway, and its expression comprises the reduction of the population of synaptic AMPA receptors. Recently, a stochastic computational model of these signalling processes demonstrated that, in single synapses, LTD is probabilistic and bistable. Here, we expanded this model to simulate LTP, which requires protein phosphatases and the increase in the population of synaptic AMPA receptors. Our results indicated that, in single synapses, while LTD is bistable, LTP is gradual. Ca(2+) induced both processes stochastically. The magnitudes of the Ca(2+) signals and the states of the signalling network regulated the likelihood of LTP and LTD and defined dynamic macroscopic Ca(2+) thresholds for the synaptic modifications in populations of synapses according to an inverse Bienenstock, Cooper and Munro (BCM) rule or a sigmoidal function. In conclusion, our model presents a unifying mechanism that explains the macroscopic properties of LTP and LTD from their dynamics in single synapses. PMID:27485552

  10. Long-term change detection from historical photography

    NASA Astrophysics Data System (ADS)

    Yoon, T.; Schenk, T.

    2006-12-01

    There is an increasing awareness in the science community about the potential of utilizing old photography and derived products together with new data for change detection and for extending the timeline as far back as possible. For example recent observations have revealed dramatic changes in the behavior of many ice streams and outlet glaciers in Greenland and Antarctica, ranging from complete shutdown of ice streams to manifold increases in velocity. Most observations are typically from the comparatively short time period since the beginning of the civilian satellite imagery (1980s), with most quantitative measurements starting only 10-15 years ago. To evaluate whether ongoing observed changes are climatically significant, changes must be determined over longer time frames. Earlier terrestrial and aerial photography and maps indeed exist and the objective of the project to disseminate these historical data and to develop techniques and tools for combining (fusing) old and new data in order to compile long-term time series of changes in the polar regions, for example in ice extent, velocity and surface elevations. The presentation focuses on new methodologies and interdisciplinary approaches that greatly facilitate the use of old photography for quantitative studies in the polar regions. An absolute prerequisite for the successful use of old photography is a rigorous registration, either with other sensory input data or with respect to 3D reference systems. Recent advances in digital photogrammetry allow registration with linear features, such as lines, curves and free-form lines without the need for identifying identical points. The concept of sensor invariant features was developed to register such disparate data sets as aerial imagery and 3D laser point clouds, originating from satellite laser altimetry or airborne laser scanning systems. Examples illustrating these concepts are shown from the Transantarctic Mountains, including the registration of aerial

  11. Stochastic Induction of Long-Term Potentiation and Long-Term Depression

    PubMed Central

    Antunes, G.; Roque, A. C.; Simoes-de-Souza, F. M.

    2016-01-01

    Long-term depression (LTD) and long-term potentiation (LTP) of granule-Purkinje cell synapses are persistent synaptic alterations induced by high and low rises of the intracellular calcium ion concentration ([Ca2+]), respectively. The occurrence of LTD involves the activation of a positive feedback loop formed by protein kinase C, phospholipase A2, and the extracellular signal-regulated protein kinase pathway, and its expression comprises the reduction of the population of synaptic AMPA receptors. Recently, a stochastic computational model of these signalling processes demonstrated that, in single synapses, LTD is probabilistic and bistable. Here, we expanded this model to simulate LTP, which requires protein phosphatases and the increase in the population of synaptic AMPA receptors. Our results indicated that, in single synapses, while LTD is bistable, LTP is gradual. Ca2+ induced both processes stochastically. The magnitudes of the Ca2+ signals and the states of the signalling network regulated the likelihood of LTP and LTD and defined dynamic macroscopic Ca2+ thresholds for the synaptic modifications in populations of synapses according to an inverse Bienenstock, Cooper and Munro (BCM) rule or a sigmoidal function. In conclusion, our model presents a unifying mechanism that explains the macroscopic properties of LTP and LTD from their dynamics in single synapses. PMID:27485552

  12. Response of a tundra ecosystem to elevated atmospheric carbon dioxide and CO{sub 2}-induced climate change. Annual technical report

    SciTech Connect

    Oechel, W.C.

    1993-02-01

    Northern ecosystems contain up to 455 Gt of C in the soil active layer and upper permafrost, which is equivalent to approximately 60% of the carbon currently in the atmosphere as CO{sub 2}. Much of this carbon is stored in the soil as dead organic matter. Its fate is subject to the net effects of global change on the plant and soil systems of northern ecosystems. The arctic alone contains about 60 Gt C, 90% of which is present in the soil active layer and upper permafrost, and is assumed to have been a sink for CO{sub 2} during the historic and recent geologic past. Depending on the nature, rate, and magnitude of global environmental change, the arctic may have a positive or negative feedback on global change. Results from the DOE- funded research efforts of 1990 and 1991 indicate that the arctic has become a source of CO{sub 2} to the atmosphere. Measurements made in the Barrow, Alaska region during 1992 support these results. This change coincides with recent climatic variation in the arctic, and suggests a positive feedback of arctic ecosystems on atmospheric CO{sub 2} and global change. There are obvious potential errors in scaling plot level measurements to landscape, mesoscale, and global spatial scales. In light of the results from the recent DOE-funded research, and the remaining uncertainties regarding the change in arctic ecosystem function due to high latitude warming, a revised set of research goals is proposed for the 1993--94 year. The research proposed in this application has four principal aspects: (A) Long- term response of arctic plants and ecosystems to elevated atmospheric CO{sub 2}. (B) Circumpolar patterns of net ecosystem CO{sub 2} flux. (C) In situ controls by temperature and moisture on net ecosystem CO{sub 2} flux. (D) Scaling of CO{sub 2} flux from plot, to landscape, to regional scales.

  13. Long-term care financing: options for the future.

    PubMed

    Mulvey, Janemarie; Li, Annelise

    2002-01-01

    The aging of the baby boomers will have an enormous impact on the future of long-term care costs. This article projects the magnitude of that impact, discusses sources of financing, and considers the cost and feasibility of three options for financing future long-term care services. The authors investigate the alternatives of increasing personal savings, raising payroll taxes and expanding employer-sponsored private long-term care insurance coverage, respectively. PMID:12004582

  14. Spatial Patterns of Atmospherically Deposited Organic Contaminants at High Elevation in the Southern Sierra Nevada Mountains, California

    EPA Science Inventory

    Atmospherically deposited contaminants in the Sierra Nevada mountains of California have been implicated as adversely affecting amphibians and fish, yet the distributions of contaminants within the mountains are poorly known, particularly at high elevation. We tested the hypothe...

  15. Long-Term Monitoring of Global Climate Forcings and Feedbacks

    NASA Technical Reports Server (NTRS)

    Hansen, J. (Editor); Rossow, W. (Editor); Fung, I. (Editor)

    1993-01-01

    A workshop on Long-Term Monitoring of Global Climate Forcings and Feedbacks was held February 3-4, 1992, at NASA's Goddard Institute for Space Studies to discuss the measurements required to interpret long-term global temperature changes, to critique the proposed contributions of a series of small satellites (Climsat), and to identify needed complementary monitoring. The workshop concluded that long-term (several decades) of continuous monitoring of the major climate forcings and feedbacks is essential for understanding long-term climate change.

  16. Highly elevated atmospheric levels of volatile organic compounds in the Uintah Basin, Utah.

    PubMed

    Helmig, D; Thompson, C R; Evans, J; Boylan, P; Hueber, J; Park, J-H

    2014-05-01

    Oil and natural gas production in the Western United States has grown rapidly in recent years, and with this industrial expansion, growing environmental concerns have arisen regarding impacts on water supplies and air quality. Recent studies have revealed highly enhanced atmospheric levels of volatile organic compounds (VOCs) from primary emissions in regions of heavy oil and gas development and associated rapid photochemical production of ozone during winter. Here, we present surface and vertical profile observations of VOC from the Uintah Basin Winter Ozone Studies conducted in January-February of 2012 and 2013. These measurements identify highly elevated levels of atmospheric alkane hydrocarbons with enhanced rates of C2-C5 nonmethane hydrocarbon (NMHC) mean mole fractions during temperature inversion events in 2013 at 200-300 times above the regional and seasonal background. Elevated atmospheric NMHC mole fractions coincided with build-up of ambient 1-h ozone to levels exceeding 150 ppbv (parts per billion by volume). The total annual mass flux of C2-C7 VOC was estimated at 194 ± 56 × 10(6) kg yr(-1), equivalent to the annual VOC emissions of a fleet of ∼100 million automobiles. Total annual fugitive emission of the aromatic compounds benzene and toluene, considered air toxics, were estimated at 1.6 ± 0.4 × 10(6) and 2.0 ± 0.5 × 10(6) kg yr(-1), respectively. These observations reveal a strong causal link between oil and gas emissions, accumulation of air toxics, and significant production of ozone in the atmospheric surface layer. PMID:24624890

  17. Effect of elevated atmospheric CO2 on carbon allocation patterns in Eriphorum vaginatum

    NASA Astrophysics Data System (ADS)

    Strom, L.

    2013-12-01

    Greenhouse gases of particular importance to the human induced greenhouse effect are, e.g., CO2 and CH4. Natural and agricultural wetlands together contribute with over 40 % of the annual atmospheric emissions of CH4 and are, therefore, considered to be the largest single contributor of this gas to the troposphere. There is a growing concern that increasing atmospheric concentrations of CO2 will stimulate CH4 production and emission from wetland ecosystems, resulting in feedback mechanisms that in future will increase the radiative forcing of these ecosystems. The aim of this study was to elucidate the effect of elevated atmospheric CO2 on fluxes of CO2 and CH4, biomass allocation patterns and amount of labile substrates (i.e. low molecular weight organic acids, OAs) for CH4 production in the root vicinity of Eriophorum vaginatum. Eriophorum cores and plants were collected at Fäjemyr, a temperate ombrotrophic bog situated in the south of Sweden. These were cultivated under controlled environmental conditions in an atmosphere of 390 or 800 ppm of CO2 (n=5 per treatment). After a one month development period gas fluxes were measured twice per week over one month using a Fourier Transform Infrared spectrometer (Gasmet Dx-4030) and OAs using a liquid chromatography-ionspray tandem mass spectrometry system (Dionex ICS-2500 and Applied Biosystems 2000 Q-Trap triple quadrupole MS). The results clearly show that elevated CO2 significantly affects all measured parts of the carbon cycle. Greenhouse gas fluxes were significantly (repeated measures test) higher under elevated CO2 conditions, NEE p < 0.0001, Reco p = 0.005, GPP p = 0.012 and CH4 p = 0.022. As were biomass of leaves, roots and concentration of OAs around the roots of plants, p = 0.045, p = 0 = 0.045 and p = 0.045 respectively (Kruskal wallis 1-way anova). The study shows higher CH4 emissions under elevated CO2 and that this may be due to a priming effect, due to input of fresh labile-C via living roots and

  18. Long-term nitrogen deposition linked to reduced water use efficiency in forests with low phosphorus availability.

    PubMed

    Huang, Zhiqun; Liu, Bao; Davis, Murray; Sardans, Jordi; Peñuelas, Josep; Billings, Sharon

    2016-04-01

    The impact of long-term nitrogen (N) deposition is under-studied in phosphorus (P)-limited subtropical forests. We exploited historically collected herbarium specimens to investigate potential physiological responses of trees in three subtropical forests representing an urban-to-rural gradient, across which N deposition has probably varied over the past six decades. We measured foliar [N] and [P] and stable carbon (δ(13) C), oxygen (δ(18) O) and nitrogen (δ(15) N) isotopic compositions in tissue from herbarium specimens of plant species collected from 1947 to 2014. Foliar [N] and N : P increased, and δ(15) N and [P] decreased in the two forests close to urban centers. Consistent with recent studies demonstrating that N deposition in the region is (15) N-depleted, these data suggest that the increased foliar [N] and N : P, and decreased [P], may be attributable to atmospheric deposition and associated enhancement of P limitation. Estimates of intrinsic water use efficiency calculated from foliar δ(13) C decreased by c. 30% from the 1950s to 2014, contrasting with multiple studies investigating similar parameters in N-limited forests. This effect may reflect decreased photosynthesis, as suggested by a conceptual model of foliar δ(13) C and δ(18) O. Long-term N deposition may exacerbate P limitation and mitigate projected increases in carbon stocks driven by elevated CO2 in forests on P-limited soils. PMID:26661404

  19. Establishing a Long Term High-Altitude Soil Moisture Monitoring Network at the Watershed Scale

    NASA Astrophysics Data System (ADS)

    Taylor, J. R.; Osenga, E. C.; Jack-Scott, E.; Arnott, J. C.; Katzenberger, J.

    2015-12-01

    The interactive Roaring Fork Observation Network (iRON) was established in the Roaring Fork Valley of Colorado in 2012 with the vision of a long-term monitoring project of benefit to both the research community and local land managers. Long-term research on high elevation precipitation patterns and soil moisture has been limited in the intermountain West of the United States. This information can provide increasingly valuable insight into ecosystem dynamics at high elevations, especially in light of climate change projections for the region and montane areas in general. The network currently ranges in elevation from roughly 1,980m to 2,700m with additional stations slated for installation this summer that will broaden that range from 1,880m to 3,000m elevation. Stations take measurements every 20 minutes on soil moisture at three depths, air temperature, relative humidity, rain, and soil temperature. Data from these stations are publicly shared on an interactive, educational website that offers context for observed changes in the local watershed, as well as opportunities for feedback and inquiry. Not only will these data have value for local land management and restoration decisions, they also will be distributed to regional, national, and international research communities as a valuable data set on long term soil moisture trends across an elevational-gradient. Collaborators include, towns, counties, non-profits and the private sector. It is intended that this data set will be continuously collected over the span of coming decades.

  20. The long-term use of cyproterone acetate in pedophilia: a case study.

    PubMed

    Cooper, A J; Cernovsky, Z; Magnus, R V

    1992-01-01

    This investigation reports the long-term use of the antiandrogen cyproterone acetate (CPA) in a pedophile, who was studied continuously over 38 months. Measures of sexual arousal, serum testosterone, and gonadotropin levels were significantly reduced by the drug as compared with placebo and no treatment; prolactin levels were significantly elevated. Some workers have observed that long-term administration of CPA (more than one year, which was then discontinued) produced enduring (in some cases apparently permanent) anti-libidinal effects; however, in the case described, within three weeks of stopping the drug, all measures had returned to pretrial levels. The importance of continuous long-term monitoring in sex offenders receiving an antiandrogen is discussed. PMID:1291700

  1. Influence of long- term aging and superimposed creep

    NASA Astrophysics Data System (ADS)

    Gope, N.; Mukherjee, T.; Sarma, D. S.

    1992-08-01

    In an effort to understand the effects of long-term aging at high temperatures and those of the superimposed creep stresses on the microstructural variations in a 0.50Cr-0.50Mo-0.25V steel, the shoulder and gage portions of the specimens subjected to stress rupture tests at 500 °C and 540 °C have been studied by transmission electron microscopy. The optical microstructure, in the normalized and tempered condition, consists of about 95 pct ferrite with the remainder bainite. The ferrite has an extremely fine precipitation of vanadium carbide (VC) as interphase precipitate as well as in random distribution. In the bainitic area, M3C is present in the globular as well as plate-like morphology. Specimens ruptured at 500 °C and 540 °C were selected for transmission electron microscopic study. Both the interphase precipitates and randomly distrib- uted precipitates of VC coarsen considerably due to prolonged exposure at elevated tempera- tures, and ultimately fine M2C platelets nucleate and grow on either side of these precipitates, resulting in the formation of the so-called H-carbides. The superimposed creep stress has a marginal effect on the coarsening kinetics of VC but has enhanced its precipitation along dis- locations and has promoted the formation of H-carbides.

  2. Elevated atmospheric CO{sub 2} alters root-microbe interactions and belowground trophic structure

    SciTech Connect

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

    1995-09-01

    Various aspects of plant and ecosystem responses to elevated atmospheric carbon dioxide have been described. However, very little is known about the fate of carbon allocated belowground, microbial activity, and trophic structure in the rhizosphere. Rhizosphere microbes are fed primarily by root-derived substrates, fulfill functions such as mineralization, immobilization, decomposition, pathogeneity, and improvement of plant nutrition, and form the base of the below-ground food web. Belowground processes have so far been monitored using a black-box approach, thereby ignoring effects of global change at a finer (functional group) level of resolution. This study is the first to describe shifts in the activity and dominance between microbial functional groups, and the results of this on higher trophic levels. We observed that, in a nutrient-rich soil, carbon flow in the plant-soil system was shunted from a mutualistic-closed, mycorrhizal dominated flow to an opportunist-open, saprobe/pathogen dominated one. This indicates that elevated atmospheric CO{sub 2} may lead to far less predictable consequences than previously thought.

  3. Impacts of elevated atmospheric CO2 on nutrient content of important food crops

    PubMed Central

    Dietterich, Lee H.; Zanobetti, Antonella; Kloog, Itai; Huybers, Peter; Leakey, Andrew D. B.; Bloom, Arnold J.; Carlisle, Eli; Fernando, Nimesha; Fitzgerald, Glenn; Hasegawa, Toshihiro; Holbrook, N. Michele; Nelson, Randall L.; Norton, Robert; Ottman, Michael J.; Raboy, Victor; Sakai, Hidemitsu; Sartor, Karla A.; Schwartz, Joel; Seneweera, Saman; Usui, Yasuhiro; Yoshinaga, Satoshi; Myers, Samuel S.

    2015-01-01

    One of the many ways that climate change may affect human health is by altering the nutrient content of food crops. However, previous attempts to study the effects of increased atmospheric CO2 on crop nutrition have been limited by small sample sizes and/or artificial growing conditions. Here we present data from a meta-analysis of the nutritional contents of the edible portions of 41 cultivars of six major crop species grown using free-air CO2 enrichment (FACE) technology to expose crops to ambient and elevated CO2 concentrations in otherwise normal field cultivation conditions. This data, collected across three continents, represents over ten times more data on the nutrient content of crops grown in FACE experiments than was previously available. We expect it to be deeply useful to future studies, such as efforts to understand the impacts of elevated atmospheric CO2 on crop macro- and micronutrient concentrations, or attempts to alleviate harmful effects of these changes for the billions of people who depend on these crops for essential nutrients. PMID:26217490

  4. Observations of the uptake of carbonyl sulfide (COS) by trees under elevated atmospheric carbon dioxide concentrations

    NASA Astrophysics Data System (ADS)

    Sandoval-Soto, L.; Kesselmeier, M.; Schmitt, V.; Wild, A.; Kesselmeier, J.

    2012-02-01

    Global change affects ecosystems to adapt to elevated atmospheric concentrations of carbon dioxide (CO2). We understand that carbonyl sulfide (COS), a trace gas which is involved in building up the stratospheric sulfate aerosol layer, is taken up by vegetation with the same triad of the enzmyes which are metabolizing the CO2, i.e. Ribulose-1,5-bisphosphate Carboxylase-Oxygenase (Rubisco), Phosphoenolpyruvate Carboxylase (PEP-Co) and carbonic anhydrase (CA). Therefore, we discuss a physiological/biochemical adaptation of these enzymes to affect the sink strength of vegetation for COS. We investigated the adaption of two European tree species, Fagus sylvatica and Quercus ilex, grown inside chambers under elevated CO2 and determined the exchange characteristics and the content of CA after a 1-2 yr period of adaption from 350 ppm to 800 ppm CO2. We could demonstrate that the COS compensation point, the CA activity and the deposition velocities may change and cause a decrease of the COS uptake by plant ecosystems. As a consequence, the atmospheric COS level may rise leading to higher input of this trace gas into the stratosphere and causing a higher energy reflection by the stratospheric sulfur aerosol into space, thus counteracting the direct radiative forcing by the tropospheric COS.

  5. The molecular and metabolic influence of long term agmatine consumption.

    PubMed

    Nissim, Itzhak; Horyn, Oksana; Daikhin, Yevgeny; Chen, Pan; Li, Changhong; Wehrli, Suzanne L; Nissim, Ilana; Yudkoff, Marc

    2014-04-01

    Agmatine (AGM), a product of arginine decarboxylation, influences multiple physiologic and metabolic functions. However, the mechanism(s) of action, the impact on whole body gene expression and metabolic pathways, and the potential benefits and risks of long term AGM consumption are still a mystery. Here, we scrutinized the impact of AGM on whole body metabolic profiling and gene expression and assessed a plausible mechanism(s) of AGM action. Studies were performed in rats fed a high fat diet or standard chow. AGM was added to drinking water for 4 or 8 weeks. We used (13)C or (15)N tracers to assess metabolic reactions and fluxes and real time quantitative PCR to determine gene expression. The results demonstrate that AGM elevated the synthesis and tissue level of cAMP. Subsequently, AGM had a widespread impact on gene expression and metabolic profiling including (a) activation of peroxisomal proliferator-activated receptor-α and its coactivator, PGC1α, and (b) increased expression of peroxisomal proliferator-activated receptor-γ and genes regulating thermogenesis, gluconeogenesis, and carnitine biosynthesis and transport. The changes in gene expression were coupled with improved tissue and systemic levels of carnitine and short chain acylcarnitine, increased β-oxidation but diminished incomplete fatty acid oxidation, decreased fat but increased protein mass, and increased hepatic ureagenesis and gluconeogenesis but decreased glycolysis. These metabolic changes were coupled with reduced weight gain and a curtailment of the hormonal and metabolic derangements associated with high fat diet-induced obesity. The findings suggest that AGM elevated the synthesis and levels of cAMP, thereby mimicking the effects of caloric restriction with respect to metabolic reprogramming. PMID:24523404

  6. Learning Auditory Space: Generalization and Long-Term Effects

    PubMed Central

    Mendonça, Catarina; Campos, Guilherme; Dias, Paulo; Santos, Jorge A.

    2013-01-01

    Background Previous findings have shown that humans can learn to localize with altered auditory space cues. Here we analyze such learning processes and their effects up to one month on both localization accuracy and sound externalization. Subjects were trained and retested, focusing on the effects of stimulus type in learning, stimulus type in localization, stimulus position, previous experience, externalization levels, and time. Method We trained listeners in azimuth and elevation discrimination in two experiments. Half participated in the azimuth experiment first and half in the elevation first. In each experiment, half were trained in speech sounds and half in white noise. Retests were performed at several time intervals: just after training and one hour, one day, one week and one month later. In a control condition, we tested the effect of systematic retesting over time with post-tests only after training and either one day, one week, or one month later. Results With training all participants lowered their localization errors. This benefit was still present one month after training. Participants were more accurate in the second training phase, revealing an effect of previous experience on a different task. Training with white noise led to better results than training with speech sounds. Moreover, the training benefit generalized to untrained stimulus-position pairs. Throughout the post-tests externalization levels increased. In the control condition the long-term localization improvement was not lower without additional contact with the trained sounds, but externalization levels were lower. Conclusion Our findings suggest that humans adapt easily to altered auditory space cues and that such adaptation spreads to untrained positions and sound types. We propose that such learning depends on all available cues, but each cue type might be learned and retrieved differently. The process of localization learning is global, not limited to stimulus-position pairs, and

  7. Long-term trends and interannual variability of water vapor over the tropics in reanalyses, CMIP5 models and observations

    NASA Astrophysics Data System (ADS)

    Takahashi, Hiroshi G.

    2015-04-01

    The strength of the hydrological cycle in the atmosphere and its long-term changes are of considerable interest, especially as the climate changes. The hydrological cycle in the atmosphere is summarized as evaporation of moisture from the earth surface (land and ocean) and precipitation into the earth surface. The global warming can modulate the strength of hydrological cycle. Many previous studies have investigated the long-term changes in precipitation. However, the investigation of the long-term changes in water vapor has been limited. We investigated the changes and interannual variability in water vapor in the atmosphere of the global scale using multiple reanalyses, CMIP5 models and observations. In reanalyses, the long-term changes in surface air temperature and PW over the tropical ocean were out of range of some observations. Both long-term changes in surface air temperature and PW may have problems. There may be no common systematic bias. The observation shows PW over ocean probably increases for recent two decades. However, the trend in PW was reduced. The reduction of the trend is associated with the hiatus of global warming after 2000's. The relationship between surface air temperature and PW was not fitted to CC relationship on the long-term trend. The long-term changes in surface air temperature and PW in the CMIP5 models are basically fitted to the CC relationship (Global mean values of water vapor were approximately 6.5-7.5% per K).

  8. Effects of elevated atmospheric carbon dioxide and temperature on soil respiration in Douglas fir seedling systems

    SciTech Connect

    Lin, C.; Ehleringer, J.R.; Rygiewicz, P.T.

    1995-09-01

    We investigated the effect of CO{sub 2} enrichment and temperature increase on root respiration, litter decomposition, consumption of soil organic matter, and overall soil respiration. Douglas fir (Pseudotsuga menziesii) seedlings were being grown in the US EPA global climate change facility in Corvallis at two atmospheric CO{sub 2} concentrations and two temperatures. Soil-respired CO{sub 2} was collected for carbon and oxygen isotope analysis. Litter and new roots were also collected from carbon isotope analyses, and litter and root water were collected for oxygen isotope analyses. Isotope data were used to distinguish the sources of CO{sub 2} between root respiration, and there was an interaction between CO{sub 2} and temperature. Elevated temperature increased only litter decomposition rate at ambient CO{sub 2}, but both root respiration and litter decomposition at elevated CO{sub 2}. Consumption of soil organic matter was a significant source for soil-respired CO{sub 2} especially at elevated CO{sub 2}.

  9. Ensuring climate information guides long-term development

    NASA Astrophysics Data System (ADS)

    Jones, Lindsey; Dougill, Andrew; Jones, Richard G.; Steynor, Anna; Watkiss, Paul; Kane, Cheikh; Koelle, Bettina; Moufouma-Okia, Wilfran; Padgham, Jon; Ranger, Nicola; Roux, Jean-Pierre; Suarez, Pablo; Tanner, Thomas; Vincent, Katharine

    2015-09-01

    Many sub-Saharan countries are failing to include climate information in long-term development planning. Ensuring climate-resilient development requires a step change in how medium- to long-term climate information is produced, communicated and utilized in sub-Saharan Africa and elsewhere.

  10. Long Term Agroecosystem Research in the southern plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Southern Plains (SP) site of the Long Term Agroecosystem Research (LTAR) network is headquartered at USDA-ARS’s Grazinglands Research Laboratory (GRL) in El Reno, Oklahoma. The GRL was established in 1948. A long-term watershed and climate research program was established in the Little Washita ...

  11. 41 CFR 51-6.3 - Long-term procurements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Long-term procurements. 51-6.3 Section 51-6.3 Public Contracts and Property Management Other Provisions Relating to Public... § 51-6.3 Long-term procurements. (a) Contracting activities are encouraged to investigate...

  12. 41 CFR 51-6.3 - Long-term procurements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Long-term procurements. 51-6.3 Section 51-6.3 Public Contracts and Property Management Other Provisions Relating to Public... § 51-6.3 Long-term procurements. (a) Contracting activities are encouraged to investigate...

  13. 7 CFR 1773.44 - Long-term debt.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 12 2011-01-01 2011-01-01 false Long-term debt. 1773.44 Section 1773.44 Agriculture... (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Required Audit Procedures and Documentation § 1773.44 Long... 691, Confirmation Schedule—Long-term Obligation to RUS as of; or RTB Form 12, Confirmation...

  14. 7 CFR 1773.44 - Long-term debt.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Long-term debt. 1773.44 Section 1773.44 Agriculture... (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Required Audit Procedures and Documentation § 1773.44 Long... 691, Confirmation Schedule—Long-term Obligation to RUS as of; or RTB Form 12, Confirmation...

  15. 7 CFR 1773.44 - Long-term debt.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Long-term debt. 1773.44 Section 1773.44 Agriculture... (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Required Audit Procedures and Documentation § 1773.44 Long... 691, Confirmation Schedule—Long-term Obligation to RUS as of; or RTB Form 12, Confirmation...

  16. 7 CFR 1773.44 - Long-term debt.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 12 2014-01-01 2013-01-01 true Long-term debt. 1773.44 Section 1773.44 Agriculture... (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Required Audit Procedures and Documentation § 1773.44 Long... 691, Confirmation Schedule—Long-term Obligation to RUS as of; or RTB Form 12, Confirmation...

  17. 7 CFR 1773.44 - Long-term debt.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 12 2013-01-01 2013-01-01 false Long-term debt. 1773.44 Section 1773.44 Agriculture... (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Required Audit Procedures and Documentation § 1773.44 Long... 691, Confirmation Schedule—Long-term Obligation to RUS as of; or RTB Form 12, Confirmation...

  18. 41 CFR 51-6.3 - Long-term procurements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Long-term procurements. 51-6.3 Section 51-6.3 Public Contracts and Property Management Other Provisions Relating to Public... § 51-6.3 Long-term procurements. (a) Contracting activities are encouraged to investigate...

  19. 41 CFR 51-6.3 - Long-term procurements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Long-term procurements. 51-6.3 Section 51-6.3 Public Contracts and Property Management Other Provisions Relating to Public... § 51-6.3 Long-term procurements. (a) Contracting activities are encouraged to investigate...

  20. 41 CFR 51-6.3 - Long-term procurements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Long-term procurements. 51-6.3 Section 51-6.3 Public Contracts and Property Management Other Provisions Relating to Public... § 51-6.3 Long-term procurements. (a) Contracting activities are encouraged to investigate...

  1. Standards for Psychological Services in Long-Term Care Facilities.

    ERIC Educational Resources Information Center

    Morrow-Howell, Nancy; Lichtenberg, Peter A.; Smith, Michael; Frazer, Deborah; Molinari, Victor; Rosowsky, Erlene; Crose, Royda; Stillwell, Nick; Kramer, Nanette; Hartman-Stein, Paula; Qualls, Sara; Salamon, Michael; Duffy, Michael; Parr, Joyce; Gallagher-Thompson, Dolores

    1998-01-01

    Describes the development of standards for psychological practice in long-term care facilities. The standards, which were developed by Psychologists in Long-Term Care, address provider characteristics, methods of referral, assessment practices, treatment, and ethical issues. Offers suggestions for use of the standards. (MKA)

  2. [Developing the core competencies of long-term care professionals].

    PubMed

    Chen, Huey-Tzy; Lee, Kuang-Ting

    2012-12-01

    Longer average life expectancies and an ageing society have made long-term care an urgent and important issue in Taiwan. Although the implementation of Long-Term Care Ten-year Project four years ago has begun showing success in terms of assessing Taiwan's needs in terms of long-term care services and resources, there has been little forward progress in terms of training, recruiting and maintaining more competent professionals in the long-term care sector. This paper explores the current state of long-term care competency in Taiwan and educational strategies in place to improve the competency of long-term care professionals. Results indicate that the term geriatric competency embraces sub-competencies in direct care, communication, assessment, teamwork, cultural sensitivities and career care competencies. The term long-term care competency embraces the sub-competencies of supervision, management, information technology, resource management, and organizational skill. As a main contributor to effective long-term care, the nursing profession must employ effective strategies to develop competency-based education. Also, the profession must have an adequate supply of competent manpower to effectively respond to Taiwan's aging society. PMID:23212250

  3. Helping People Make Better Long-Term-Care Decisions

    ERIC Educational Resources Information Center

    Kane, Robert L.; Boston, Krista; Chilvers, Mary

    2007-01-01

    Purpose: The purpose of this article is to describe an innovative online system to support long-term-care decision making. Design and Methods: The Long-Term Care Choices tool is a web-based system that uses expert opinion and structures decision making. Results: The system has been well accepted, and most users find it easy to use. Implications:…

  4. LONG TERM CARE FACILITIES: A CORNUCOPIA OF VIRAL PATHOGENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our study sought to determine the frequency and types of respiratory viruses circulating in 33 Boston long term care facilities during a three year period and correlate rates of infection with serum zinc levels. Participants were residents of long term care that had previously participated in a tria...

  5. Developmental Dyslexia and Explicit Long-Term Memory

    ERIC Educational Resources Information Center

    Menghini, Deny; Carlesimo, Giovanni Augusto; Marotta, Luigi; Finzi, Alessandra; Vicari, Stefano

    2010-01-01

    The reduced verbal long-term memory capacities often reported in dyslexics are generally interpreted as a consequence of their deficit in phonological coding. The present study was aimed at evaluating whether the learning deficit exhibited by dyslexics was restricted only to the verbal component of the long-term memory abilities or also involved…

  6. Long-term trends in precipitation and surface water chemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter shows long-term data and trends in precipitation and surface water chemistry for each site. It contains a brief introduction to the topic, and methods of measurements, selection of variables, and their data source. It consists primarily of a large number of figures showing long-term da...

  7. Factors Affecting Long-Term Abstinence from Substances Use

    ERIC Educational Resources Information Center

    Elsheikh, Salah Elgaily

    2008-01-01

    Objective: The purpose of this study is to explore the attitudes of abstainers from drug use that relate to the factors leading to long-term abstinence. Materials and Methods: Cross-sectional study was carried out in Al-Amal Hospital to examine, which attitudes of abstainers related to long-term abstinence. A random survey was conducted on 62…

  8. Research Experience for Teachers at NRAO-Green Bank: Atmospheric Refraction at Low Elevation

    NASA Astrophysics Data System (ADS)

    Paradis, Jeff; Maddalena, R. J.

    2009-01-01

    During the summer, 2008 Research Experience for Teachers, J. Paradis worked at the NRAO in Green Bank to collect and reduce data taken on the 43-m radio telescope to compare models of atmospheric refraction at elevations below 10º. Unlike optical telescopes, radio telescopes cannot use guide stars to overcome deficiencies in refraction models but, instead, need accurate refraction predictions. The GBT, for example, has a large aperture, observes at high frequencies and to low elevations, and requires a model that is accurate to a few arc seconds. Unfortunately, there is no radio refraction model that has been universally accepted, with some of the most common models differing by up to an arc minute at the horizon. There are a number of advantages in using the 43-m telescope at 1 GHz to measure refraction using the Moon as a source. The telescope can observe to the horizon, the Moon's size closely matches the beam width of the telescope, and the Moon is bright enough to have its position measured accurately in under 30 sec. Most importantly, the equatorial mount of the telescope, when combined with the monthly changing azimuth of Moon rises and sets, makes it possible to disentangle telescope pointing errors from refraction. So far we have not collected sufficient data for a complete analysis, but lessons for high school students have been developed that embrace the core concepts of the summers’ efforts. Using BUFKIT, a weather forecast program developed by the National Weather Service, students in physics classes determine the atmospheric refraction at different elevations for fictional radio and optical telescopes in upstate New York. Students are given a pre and post test assessment to measure understanding for a topic students traditionally find difficult. This work was supported in part by the NSF-RET program

  9. Effects of Elevated Atmospheric CO2 on Soil CO2 Efflux in Conventional and Conservation Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elevated atmospheric carbon dioxide (CO2) can affect both the quantity and quality of plant tissues produced, which will impact the cycling and storage of carbon (C) within plant/soil systems and thus the rate of CO2 release back to the atmosphere. Research is needed to more accurately quantify the...

  10. Reduced net atmospheric CH4 consumption is a sustained response to elevated CO2 in a temperate forest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We compared nearly continuously from 1998 until 2006 rates of soil atmosphere CH4 exchange at permanently established sampling sites in a temperate loblolly pine (Pinus taeda) forest exposed to ambient (control plots; approx. 380 uL L-1) or elevated (ambient + 200 uL L-1) CO2. Net atmospheric CH4 co...

  11. The relationship between interannual and long-term cloud feedbacks

    SciTech Connect

    Zhou, Chen; Zelinka, Mark D.; Dessler, Andrew E.; Klein, Stephen A.

    2015-12-11

    The analyses of Coupled Model Intercomparison Project phase 5 simulations suggest that climate models with more positive cloud feedback in response to interannual climate fluctuations also have more positive cloud feedback in response to long-term global warming. Ensemble mean vertical profiles of cloud change in response to interannual and long-term surface warming are similar, and the ensemble mean cloud feedback is positive on both timescales