Science.gov

Sample records for long-term elevated atmospheric

  1. Long-term elevated atmospheric CO2 enhances forest productivity

    NASA Astrophysics Data System (ADS)

    Loecke, T. D.; Groffman, P. M.; Treseder, K. K.; LaDeau, S.

    2011-12-01

    Global atmospheric CO2 concentrations are increasing at historically unprecedented but ecologically gradual rates. The implications of this perturbation for carbon sequestration and feedback on global climate change are difficult to predict due in part to its gradual and largely uniform nature. We used long-term (>40 years) spatial gradients in atmospheric CO2 concentration, produced by spatially heterogeneous fossil fuel combustion along a rural to urban transect, to test the hypotheses that 1) rural to urban CO2 spatial gradients are useful analogs for gradual climate change and 2) higher atmospheric CO2 concentration promotes tree growth and C sequestration. Fossil fuel derived CO2 imparts a distinctive 14C isotopic signature on atmospheric CO2; as this CO2 is fixed into annual tree rings, a proxy for fossil fuel derived CO2 is preserved. Ten four-year tree ring segments were analyzed for α-cellulose 14C content by AMS from trees within 10 closed canopy forested sites in the Baltimore Maryland metropolitan area. Tree growth parameters were assessed by measuring the annual ring width change of 224 trees across the 10 sites. A hierarchical Bayesian model was constructed to determine the influence of CO2 concentration and other site and environmental factors on tree growth. Our proxy for historical CO2 concentrations indicates a detectable but diminishing spatial CO2 gradient across the rural to urban transect that ranged from a 5.6% gradient during the 1970s to a 1.4% gradient in recent years (2000-2008). This observation is consistent with urban deindustrialization and concurrent expansion of suburban development. As an analog for future atmospheric conditions, this spatial gradient is equivalent to a temporal gradient of ca. 15, 7.2, 9.8, 2.6 years of atmospheric CO2 rise during the past four decades. The CO2 spatial gradient had an overall positive effect on tree size adjusted ring width growth. Modeled air surface temperature differences among sites indicate

  2. Long-term leaf production response to elevated atmospheric carbon dioxide and tropospheric ozone

    Treesearch

    Alan F. Talhelm; Kurt S. Pregitzer; Christian P. Giardina

    2011-01-01

    Elevated concentrations of atmospheric CO2 and tropospheric O3 will profoundly influence future forest productivity, but our understanding of these influences over the long-term is poor. Leaves are key indicators of productivity and we measured the mass, area, and nitrogen concentration of leaves collected in litter traps...

  3. 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.

  4. 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)

  5. Long-term culture at elevated atmospheric CO2 fails to evoke specific adaptation in seven freshwater phytoplankton species

    PubMed Central

    Low-Décarie, Etienne; Jewell, Mark D.; Fussmann, Gregor F.; Bell, Graham

    2013-01-01

    The concentration of CO2 in the atmosphere is expected to double by the end of the century. Experiments have shown that this will have important effects on the physiology and ecology of photosynthetic organisms, but it is still unclear if elevated CO2 will elicit an evolutionary response in primary producers that causes changes in physiological and ecological attributes. In this study, we cultured lines of seven species of freshwater phytoplankton from three major groups at current (approx. 380 ppm CO2) and predicted future conditions (1000 ppm CO2) for over 750 generations. We grew the phytoplankton under three culture regimes: nutrient-replete liquid medium, nutrient-poor liquid medium and solid agar medium. We then performed reciprocal transplant assays to test for specific adaptation to elevated CO2 in these lines. We found no evidence for evolutionary change. We conclude that the physiology of carbon utilization may be conserved in natural freshwater phytoplankton communities experiencing rising atmospheric CO2 levels, without substantial evolutionary change. PMID:23303540

  6. Fungal community composition and function after long-term exposure of northern forests to elevated atmospheric CO2 and tropospheric O3

    Treesearch

    Ivan P. Edwards; Donald R. Zak

    2011-01-01

    The long-term effects of rising atmospheric carbon dioxide (CO2) and tropospheric O3 concentrations on fungal communities in soil are not well understood. Here, we examine fungal community composition and the activities of cellobiohydrolase and N-acetylglucosaminidase (NAG) after 10 years of exposure to 1...

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

    PubMed

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

    2015-05-27

    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.

  8. 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

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

    Treesearch

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

    2008-01-01

    The Rhinelander free-air CO2 enrichment (FACE) experiment is designed to understand ecosystem response to elevated atmospheric carbon dioxide (+CO2) and elevated tropospheric ozone (+O3). The objectives of this study were: to understand how soil respiration responded to the experimental treatments; to...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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.

  15. 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.

  16. 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.

  17. Relation of perioperative elevation of troponin to long-term mortality after orthopedic surgery.

    PubMed

    Oberweis, Brandon S; Smilowitz, Nathaniel R; Nukala, Swetha; Rosenberg, Andrew; Xu, Jinfeng; Stuchin, Steven; Iorio, Richard; Errico, Thomas; Radford, Martha J; Berger, Jeffrey S

    2015-06-15

    Myocardial necrosis in the perioperative period of noncardiac surgery is associated with short-term mortality, but long-term outcomes have not been characterized. We investigated the association between perioperative troponin elevation and long-term mortality in a retrospective study of consecutive subjects who underwent hip, knee, and spine surgery. Perioperative myocardial necrosis and International Classification of Disease, Ninth Revision-coded myocardial infarction (MI) were recorded. Long-term survival was assessed using the Social Security Death Index database. Logistic regression models were used to identify independent predictors of long-term mortality. A total of 3,050 subjects underwent surgery. Mean age was 60.8 years, and 59% were women. Postoperative troponin was measured in 1,055 subjects (34.6%). Myocardial necrosis occurred in 179 cases (5.9%), and MI was coded in 20 (0.7%). Over 9,015 patient-years of follow-up, 111 deaths (3.6%) occurred. Long-term mortality was 16.8% in subjects with myocardial necrosis and 5.8% with a troponin in the normal range. Perioperative troponin elevation (hazard ratio 2.33, 95% confidence interval 1.33 to 4.10) and coded postoperative MI (adjusted hazard ratio 3.51, 95% confidence interval 1.44 to 8.53) were significantly associated with long-term mortality after multivariable adjustment. After excluding patients with coronary artery disease and renal dysfunction, myocardial necrosis remained associated with long-term mortality. In conclusion, postoperative myocardial necrosis is common after orthopedic surgery. Myocardial necrosis is independently associated with long-term mortality at 3 years and may be used to identify patients at higher risk for events who may benefit from aggressive management of cardiovascular risk factors.

  18. Atmospheric carbon dioxide removal: long-term consequences and commitment

    NASA Astrophysics Data System (ADS)

    Cao, Long; Caldeira, Ken

    2010-04-01

    Carbon capture from ambient air has been proposed as a mitigation strategy to counteract anthropogenic climate change. We use an Earth system model to investigate the response of the coupled climate-carbon system to an instantaneous removal of all anthropogenic CO2 from the atmosphere. In our extreme and idealized simulations, anthropogenic CO2 emissions are halted and all anthropogenic CO2 is removed from the atmosphere at year 2050 under the IPCC A2 CO2 emission scenario when the model-simulated atmospheric CO2 reaches 511 ppm and surface temperature reaches 1.8 °C above the pre-industrial level. In our simulations a one-time removal of all anthropogenic CO2 in the atmosphere reduces surface air temperature by 0.8 °C within a few years, but 1 °C surface warming above pre-industrial levels lasts for several centuries. In other words, a one-time removal of 100% excess CO2 from the atmosphere offsets less than 50% of the warming experienced at the time of removal. To maintain atmospheric CO2 and temperature at low levels, not only does anthropogenic CO2 in the atmosphere need to be removed, but anthropogenic CO2 stored in the ocean and land needs to be removed as well when it outgasses to the atmosphere. In our simulation to maintain atmospheric CO2 concentrations at pre-industrial levels for centuries, an additional amount of CO2 equal to the original CO2 captured would need to be removed over the subsequent 80 years.

  19. Rod-type extensometers in long-term elevated temperature service

    NASA Astrophysics Data System (ADS)

    Dubois, A. O.; Nelson, P. H.; Hood, M.; Binnall, E.

    1982-09-01

    At Stripa, Sweden, 35 rod type extensometers were used to measure displacements within the granite rock mass surrounding electrical heaters emplaced in the floor of an underground entry. The performance of currently available rock instrumentation when subjected to long term service at elevated temperatures are thermomechanically evaluated.

  20. Long-term investigation of atmospheric mercury contamination in Connecticut.

    PubMed

    Nadim, F; Perkins, C; Liu, S; Carley, R J; Hoag, G E

    2001-11-01

    Atmospheric mercury was monitored from January 1997 through the end of December 1999 in eight sampling locations in Connecticut. Four sampling locations were chosen along the shores of Long Island Sound and four were chosen in interior sections of Connecticut. Sampling locations were chosen to represent both rural and urban sectors. Average concentrations of gaseous and particulate mercury were found to be 2.06 ng/m3 and 10.5 pg/m3, respectively. The weekly average wet deposition fluxes of mercury and methylmercury over the three-year sampling period were measured to be 611 and 11 microg/ha/week, respectively. Concentrations of gaseous, particulate and wet flux of mercury were found to be significantly higher in urban areas than the rural sampling locations. There was, however, no significant difference between the mean gaseous and particulate concentrations of mercury in coastal and inland sampling locations. No significant difference was observed either between the wet fluxes of total mercury in coastal and inland sampling locations and there was no spatial gradient for mercury concentration and deposition. The data of this study suggest that vehicular traffic and localized emission sources in urban areas play a significant role in determining the atmospheric concentration of mercury in Connecticut.

  1. The long-term carbon cycle, fossil fuels and atmospheric composition.

    PubMed

    Berner, Robert A

    2003-11-20

    The long-term carbon cycle operates over millions of years and involves the exchange of carbon between rocks and the Earth's surface. There are many complex feedback pathways between carbon burial, nutrient cycling, atmospheric carbon dioxide and oxygen, and climate. New calculations of carbon fluxes during the Phanerozoic eon (the past 550 million years) illustrate how the long-term carbon cycle has affected the burial of organic matter and fossil-fuel formation, as well as the evolution of atmospheric composition.

  2. 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

  3. Long-Term Simulated Atmospheric Nitrogen Deposition Alters ...

    EPA Pesticide Factsheets

    Atmospheric nitrogen deposition has been suggested to increase forest carbon sequestration across much of the Northern Hemisphere; slower organic matter decomposition could contribute to this increase. At four sugar maple (Acer saccharum)-dominated northern hardwood forests, we previously observed that 10 years of chronic simulated nitrogen deposition (30 kg N ha-1 yr-1) increased soil organic carbon. Over three years at these sites, we investigated the effects of nitrogen additions on decomposition of two substrates with documented differences in biochemistry: leaf litter (more labile) and fine roots (more recalcitrant). Further, we combined decomposition rates with annual leaf and fine root litter production to estimate how nitrogen additions altered the accumulation of soil organic matter. Nitrogen additions marginally stimulated early-stage decomposition of leaf litter, a substrate with little acid-insoluble material (e.g., lignin). In contrast, nitrogen additions inhibited the late stage decomposition of fine roots, a substrate with high amount of acid insoluble material and a change consistent with observed decreases in lignin-degrading enzyme activities with nitrogen additions at these sites. At the ecosystem scale, the slower fine root decomposition led to additional root mass retention (g m-2), which explained 5, 48, and 52 % of previously-documented soil carbon accumulation due to nitrogen additions. Our results demonstrated that nitrogen deposition ha

  4. A Long-term Forest Fertilization Experiment to Understand Ecosystem Responses to Atmospheric Nitrogen Deposition

    NASA Astrophysics Data System (ADS)

    Baron, J.; Advani, S. M.; Allen, J.; Boot, C.; Denef, K.; Denning, S.; Hall, E.; Moore, J. C.; Reuth, H.; Ryan, M. G.; Shaw, E.

    2016-12-01

    Long-term field experiments can reveal changes in ecosystem processes that may not be evident in short-term studies. Short-term measurements or experiments may have narrower objectives or unrealistic treatments in order to see a change, whereas long-term studies can reveal complex interactions that take longer to manifest. We report results from a long-term experiment (1996 to present) in subalpine forests to simulate the consequences of sustained atmospheric nitrogen (N) deposition. Loch Vale watershed in Rocky Mountain National Park, the location of the experiment, has received an order of magnitude greater atmospheric N deposition than estimated background since mid-20th Century. Augmenting that, in 1996 we began adding 25 kg NH4NO3 ha-1 yr-1 to three 30m x 30m old-growth Engelmann spruce and subalpine fir plots. Treated stands were matched by nearby controls. N addition caused rapid leaching of nitrate and cations from soils, and increased N mineralization and nitrification rates. These observations in the fertilized plots have been sustained over time. Soluble aluminum concentrations do not differ significantly between fertilized and control plots, but treated soils are now markedly more acidic (pH of 4.7) than original soil and controls (pH of 5.1); further acidification might increase aluminum leaching. Effects on soil carbon were complex, mediated by reductions in total microbial biomass, decreases in arbuscular mychorrizal and saprotropic fungi, and increased potential rates of N enzyme degrading activities. Initial soil C:N of 24 was lower than similar soils in low N deposition stands (C:N of 36). The C:N declined to 22 with treatment. Fertilized plots lost 11% soil C, but the mechanism is unclear. We did not measure changes in C inputs from litter, microbial biomass, or plant uptake, but there was no change in summer CO2 flux, measured in 2003, 2004, and 2014. Leaching of DOC from fertilized plots was elevated throughout the experiment, providing one

  5. Spring leaf flush in aspen (Populus tremuloides) clones is altered by long-term growth at elevated carbon dioxide and elevated ozone concentration.

    PubMed

    McGrath, Justin M; Karnosky, David F; Ainsworth, Elizabeth A

    2010-04-01

    Early spring leaf out is important to the success of deciduous trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how long-term growth at elevated carbon dioxide concentration ([CO(2)]) and elevated ozone concentration ([O(3)]) altered leaf area index development in a closed Populus tremuloides (aspen) canopy. This work was done at the Aspen FACE experiment where aspen clones have been grown since 1997 in conditions simulating the [CO(2)] and [O(3)] predicted for approximately 2050. The responses of two clones were compared during the first month of spring leaf out when CO(2) fumigation had begun, but O(3) fumigation had not. Trees in elevated [CO(2)] plots showed a stimulation of leaf area index (36%), while trees in elevated [O(3)] plots had lower leaf area index (-20%). While individual leaf area was not significantly affected by elevated [CO(2)], the photosynthetic operating efficiency of aspen leaves was significantly improved (51%). There were no significant differences in the way that the two aspen clones responded to elevated [CO(2)]; however, the two clones responded differently to long-term growth at elevated [O(3)]. The O(3)-sensitive clone, 42E, had reduced individual leaf area when grown at elevated [O(3)] (-32%), while the tolerant clone, 216, had larger mature leaf area at elevated [O(3)] (46%). These results indicate a clear difference between the two clones in their long-term response to elevated [O(3)], which could affect competition between the clones, and result in altered genotypic composition in future atmospheric conditions.

  6. 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.

  7. Millstone Hill ISR observations of upper atmospheric long-term changes: Height dependency

    NASA Astrophysics Data System (ADS)

    Zhang, Shun-Rong; Holt, John M.; Kurdzo, James

    2011-05-01

    Ionospheric ion temperature is an excellent approximation to neutral temperature in the upper atmosphere, especially, for altitudes below 300 km. This analysis of long-term ionospheric ion temperature changes between 100 and 550 km at noon is based on a database of incoherent scatter radar observations spanning more than three solar cycles during 1968-2006 at Millstone Hill and provides direct evidence of long-term changes and their height dependency in the upper atmospheric temperature. A cooling trend at altitudes above 200 km and an apparent warming trend below 200 km are found. The cooling increases with height and shows variability with solar activity. The apparent warming varies with season and solar activity. It may result from the thermal subsidence caused by atmospheric contraction and pressure level change and from the ion temperature overestimation in the F1 region due to ion composition long-term changes. These long-term changes in ion temperature are accompanied by changes in electron density, being lower above the F2 peak and higher below the F2 peak. Electron temperature is accordingly enhanced. All these changes appear to be suggestive of a long-term greenhouse gas effect.

  8. 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.

  9. Long-term monitoring of high-elevation white pine communities in Pacific West Region National Parks

    Treesearch

    Shawn T. McKinney; Tom Rodhouse; Les Chow; Penelope Latham; Daniel Sarr; Lisa Garrett; Linda Mutch

    2011-01-01

    National Park Service Inventory and Monitoring (I&M) networks conduct long-term monitoring to provide park managers information on the status and trends in key biological and environmental attributes (Vital Signs). Here we present an overview of a collaborative approach to long-term monitoring of high-elevation white pine forest dynamics among three Pacific West...

  10. Long-term outcomes of minor troponin elevations in the intensive care unit.

    PubMed

    Velasquez, A; Ghassemi, M; Szolovits, P; Park, S; Osorio, J; Dejam, A; Celi, L

    2014-05-01

    The aim of our study is to determine the short-term and long-term outcomes of intensive care unit (ICU) patients with minor troponin elevations. The retrospective study compared ICU patients with peak troponin elevation less than 0.1 ng/ml to those with only negative tests during their hospital stay. Data were gathered from ICUs at Beth Israel Deaconess Medical Center between 2001 and 2008. A total of 4224 patients (2547 controls and 1677 positives) were analysed. The primary outcome was mortality at one year. Secondary outcomes were 30-day mortality and hospital and ICU lengths of stay. After adjusting for age, sex, Simplified Acute Physiology Score, Sequential Organ Failure Assessment and combined Elixhauser score, we found that minor troponin elevations (peak troponin elevation between 0.01 and 0.09 ng/ml) were associated with a higher one-year mortality (Hazard Ratio 1.22, P <0.001 for binary troponin presence; Hazard Ratio 1.03, P <0.001 for each 0.01 ng/ml troponin increment). This relationship held for the subgroup of seven-day post-discharge survivors (Hazard Ratio 1.26, P <0.001). Minor elevations of troponin also significantly increased the net reclassification index over traditional risk markers for mortality prediction (net reclassification score 0.12, P <0.001). Minor troponin elevation was also associated with 30-day mortality (odds ratio 1.33, P=0.003). Importantly, troponin testing did not increase the adjusted mortality odds (P=0.9). Minor elevations in troponin substantially increase one-year, all-cause mortality in a stepwise fashion; it was also independently associated with 30-day mortality. We propose that minor elevations in troponin should not be regarded as clinically unimportant, but rather be included as a prognostic element if measured. We recommend prospective ICU studies to assess prognostic value of routine troponin determination.

  11. Progressive N limitation in forests: review and implications for long-term responses to elevated CO2.

    PubMed

    Johnson, Dale W

    2006-01-01

    Field studies have shown that elevated CO2 can cause increased forest growth over the short term (<6 years) even in the face of N limitation. This is facilitated to some degree by greater biomass production per unit N uptake (lower tissue N concentrations), but more often than not, N uptake is increased with elevated CO2 as well. Some studies also show that N sequestration in the forest floor is increased with elevated CO2. These findings raise the questions of where the "extra" N comes from and how long such growth increases can continue without being truncated by progressive N limitation (PNL). This paper reviews some of the early nutrient cycling literature that describes PNL during forest stand development and attempts to use this information, along with recent developments in soil N research, to put the issue of PNL with elevated CO2 into perspective. Some of the early studies indicated that trees can effectively "mine" N from soils over the long term, and more recent developments in soil N cycling research suggest mechanisms by which this might have occurred. However, both the early nutrient cycling literature and more recent simulation modeling suggest that PNL will at some point truncate the observed increases in growth and nutrient uptake with elevated CO2, unless external inputs of N are increased by either N fixation or atmospheric deposition.

  12. Does long-term cultivation of saplings under elevated CO2 concentration influence their photosynthetic response to temperature?

    PubMed Central

    Šigut, Ladislav; Holišová, Petra; Klem, Karel; Šprtová, Mirka; Calfapietra, Carlo; Marek, Michal V.; Špunda, Vladimír; Urban, Otmar

    2015-01-01

    Background and Aims Plants growing under elevated atmospheric CO2 concentrations often have reduced stomatal conductance and subsequently increased leaf temperature. This study therefore tested the hypothesis that under long-term elevated CO2 the temperature optima of photosynthetic processes will shift towards higher temperatures and the thermostability of the photosynthetic apparatus will increase. Methods The hypothesis was tested for saplings of broadleaved Fagus sylvatica and coniferous Picea abies exposed for 4–5 years to either ambient (AC; 385 µmol mol−1) or elevated (EC; 700 µmol mol−1) CO2 concentrations. Temperature response curves of photosynthetic processes were determined by gas-exchange and chlorophyll fluorescence techniques. Key Results Initial assumptions of reduced light-saturated stomatal conductance and increased leaf temperatures for EC plants were confirmed. Temperature response curves revealed stimulation of light-saturated rates of CO2 assimilation (Amax) and a decline in photorespiration (RL) as a result of EC within a wide temperature range. However, these effects were negligible or reduced at low and high temperatures. Higher temperature optima (Topt) of Amax, Rubisco carboxylation rates (VCmax) and RL were found for EC saplings compared with AC saplings. However, the shifts in Topt of Amax were instantaneous, and disappeared when measured at identical CO2 concentrations. Higher values of Topt at elevated CO2 were attributed particularly to reduced photorespiration and prevailing limitation of photosynthesis by ribulose-1,5-bisphosphate (RuBP) regeneration. Temperature response curves of fluorescence parameters suggested a negligible effect of EC on enhancement of thermostability of photosystem II photochemistry. Conclusions Elevated CO2 instantaneously increases temperature optima of Amax due to reduced photorespiration and limitation of photosynthesis by RuBP regeneration. However, this increase disappears when plants

  13. Does long-term cultivation of saplings under elevated CO2 concentration influence their photosynthetic response to temperature?

    PubMed

    Šigut, Ladislav; Holišová, Petra; Klem, Karel; Šprtová, Mirka; Calfapietra, Carlo; Marek, Michal V; Špunda, Vladimír; Urban, Otmar

    2015-11-01

    Plants growing under elevated atmospheric CO2 concentrations often have reduced stomatal conductance and subsequently increased leaf temperature. This study therefore tested the hypothesis that under long-term elevated CO2 the temperature optima of photosynthetic processes will shift towards higher temperatures and the thermostability of the photosynthetic apparatus will increase. The hypothesis was tested for saplings of broadleaved Fagus sylvatica and coniferous Picea abies exposed for 4-5 years to either ambient (AC; 385 µmol mol(-1)) or elevated (EC; 700 µmol mol(-1)) CO2 concentrations. Temperature response curves of photosynthetic processes were determined by gas-exchange and chlorophyll fluorescence techniques. Initial assumptions of reduced light-saturated stomatal conductance and increased leaf temperatures for EC plants were confirmed. Temperature response curves revealed stimulation of light-saturated rates of CO2 assimilation (Amax) and a decline in photorespiration (RL) as a result of EC within a wide temperature range. However, these effects were negligible or reduced at low and high temperatures. Higher temperature optima (Topt) of Amax, Rubisco carboxylation rates (VCmax) and RL were found for EC saplings compared with AC saplings. However, the shifts in Topt of Amax were instantaneous, and disappeared when measured at identical CO2 concentrations. Higher values of Topt at elevated CO2 were attributed particularly to reduced photorespiration and prevailing limitation of photosynthesis by ribulose-1,5-bisphosphate (RuBP) regeneration. Temperature response curves of fluorescence parameters suggested a negligible effect of EC on enhancement of thermostability of photosystem II photochemistry. Elevated CO2 instantaneously increases temperature optima of Amax due to reduced photorespiration and limitation of photosynthesis by RuBP regeneration. However, this increase disappears when plants are exposed to identical CO2 concentrations. In

  14. 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

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

    Treesearch

    Michael C. Wiemann; David Kretschmann; Alan Rudie; Bruce A. Kimball; Sherwood B. Idso

    2008-01-01

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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  17. Long-term exposure to elevated CO2 and O3 alters aspen foliar chemistry across developmental stages.

    PubMed

    Couture, J J; Holeski, L M; Lindroth, R L

    2014-03-01

    Anthropogenic activities are altering levels of greenhouse gases to the extent that multiple and diverse ecosystem processes are being affected. Two gases that substantially influence forest health are atmospheric carbon dioxide (CO2 ) and tropospheric ozone (O3 ). Plant chemistry will play an important role in regulating ecosystem processes in future environments, but little information exists about the longitudinal effects of elevated CO2 and O3 on phytochemistry, especially for long-lived species such as trees. To address this need, we analysed foliar chemical data from two genotypes of trembling aspen, Populus tremuloides, collected over 10 years of exposure to levels of CO2 and O3 predicted for the year 2050. Elevated CO2 and O3 altered both primary and secondary chemistry, and the magnitude and direction of the responses varied across developmental stages and between aspen genotypes. Our findings suggest that the effects of CO2 and O3 on phytochemical traits that influence forest processes will vary over tree developmental stages, highlighting the need to continue long-term, experimental atmospheric change research. © 2013 John Wiley & Sons Ltd.

  18. 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.

  19. 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.

  20. Proinflammatory cytokines remain elevated despite long-term remission in Cushing's disease: a prospective study.

    PubMed

    Shah, Nirali; Ruiz, Henry H; Zafar, Usman; Post, Kalmon D; Buettner, Christoph; Geer, Eliza B

    2017-01-01

    Inflammation contributes to the development of metabolic and cardiovascular disease. Cushing's disease (CD), a state of chronic glucocorticoid (GC) excess characterized by visceral obesity and insulin resistance, may be associated with increased systemic inflammation. Cardiovascular mortality in CD remains elevated even after successful remission. It is unclear whether a chronic low-grade inflammatory state persists even after remission of CD, which may account for the increased CVD mortality. (1) To assess circulating proinflammatory cytokines in patients with active CD and BMI-matched controls; (2) to prospectively follow plasma cytokine concentrations in patients with CD before and after surgical remission; and (3) to assess whether plasma cytokine concentrations correlate with adipose tissue distribution and ectopic lipid content in liver and muscle. Plasma cytokines from prospectively enrolled patients with CD (N = 31) were quantified during active disease (v1) vs controls (N = 18) and 19·5 ± 12·9 months after surgical remission (v2). Fasting plasma IL-6, IL-1β, TNF-α, IL-8, IL-17 and IL-10 were quantified using a multiplex assay. Total and regional fat masses were measured by whole-body MRI. Circulating IL-6 and IL-1β were elevated in patients with active CD vs controls (P < 0·05) and remained elevated in CD after surgical remission, despite decreases in BMI (P < 0·001), HOMA-IR (P < 0·001), and visceral, hepatic and intermuscular fat (P < 0·001, <0·001 and 0·03, respectively). Despite long-term remission and improvements in fat distribution and insulin sensitivity, patients with CD may suffer from a state of chronic low-grade inflammation, which could contribute to increased cardiovascular mortality. © 2016 John Wiley & Sons Ltd.

  1. Impact of Radiatively Active Trace Gases on Long-Term Changes in the Middle Atmosphere

    NASA Astrophysics Data System (ADS)

    Qian, L.; Marsh, D. R.; Merkel, A. W.; Solomon, S. C.

    2014-12-01

    We conduct model simulations to examine how changes in concentration of radiatively active trace gases affect long-term changes in the middle atmosphere. We focus our model study on the impact of increases in carbon dioxide and methane, and decreases in ozone, between 1983 and 2003. The increase of carbon dioxide can cool the middle atmosphere through infrared emission at 15 microns, ozone depletion can cause cooling in the stratosphere and mesosphere through reduced solar heating, whereas the enhancement of methane, which increases water vapor, can introduce a cooling through reduced chemical heating or a warming through increased solar heating. We investigate the effect of each gas separately as well as the combined effect, using the National Center for Atmospheric Research (NCAR) Whole Atmosphere Community Climate Model (WACCM).

  2. Elevated rheumatoid factor and long term risk of rheumatoid arthritis: a prospective cohort study

    PubMed Central

    Nielsen, Sune F; Bojesen, Stig E; Schnohr, Peter

    2012-01-01

    Objective To test whether elevated concentration of rheumatoid factor is associated with long term development of rheumatoid arthritis. Design A prospective cohort study, the Copenhagen City Heart Study. Blood was drawn in 1981-83, and participants were followed until 10 August 2010. Setting Copenhagen general population. Participants 9712 white Danish individuals from the general population aged 20-100 years without rheumatoid arthritis at study entry. Main outcome measures Rheumatoid arthritis according to baseline plasma IgM rheumatoid factor level categories of 25-50, 50.1-100, and >100, versus <25 IU/mL. Results Rheumatoid factor levels were similar from age 20 to 100 years. During 187 659 person years, 183 individuals developed rheumatoid arthritis. In healthy individuals, a doubling in levels of rheumatoid factor was associated with a 3.3-fold (95% confidence interval 2.7 to 4.0) increased risk of developing rheumatoid arthritis, with a similar trend for most other autoimmune rheumatic diseases. The cumulative incidence of rheumatoid arthritis increased with increasing rheumatoid factor category (Ptrend<0.0001). Multivariable adjusted hazard ratios for rheumatoid arthritis were 3.6 (95% confidence interval 1.7 to 7.3) for rheumatoid factor levels of 25-50 IU/mL, 6.0 (3.4 to 10) for 50.1-100 IU/mL, and 26 (15 to 46) for >100 IU/mL, compared with <25 IU/mL (Ptrend<0.0001). The highest absolute 10 year risk of rheumatoid arthritis of 32% was observed in 50-69 years old women who smoked with rheumatoid factor levels >100 IU/mL. Conclusion Individuals in the general population with elevated rheumatoid factor have up to 26-fold greater long term risk of rheumatoid arthritis, and up to 32% 10 year absolute risk of rheumatoid arthritis. These novel findings may lead to revision of guidelines for early referral to a rheumatologist and early arthritis clinics based on rheumatoid factor testing. PMID:22956589

  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. An empirical response function for the long-term fate of excess atmospheric CO2

    NASA Astrophysics Data System (ADS)

    Lord, Natalie S.; Ridgwell, Andy; Thorne, Mike. C.; Lunt, Dan. J.

    2015-04-01

    The long-term fate of fossil fuel CO2 emitted to the atmosphere is neutralization by a number of sedimentological and geological processes operating on timescales ranging from thousands to hundreds of thousands of years. However, the response of these carbon cycle processes to increasing total emissions is not known, such as whether saturation of the long-term CO2 sinks might occur or a weakening of the associated feedbacks. This could have important implications for components of the Earth system that are slow to respond to changes in temperature, such as ice sheets and methane hydrates. Here we use a 3D ocean-based Earth system model to assess the relative importance and timescales of these processes for different total emissions. A multi-exponential analysis is performed on an ensemble of 1 Myr duration CO2 decay curves spanning cumulative emissions of up to 20,000 PgC, generating an empirical response function characterizing the long-term (> 1 kyr) fate of CO2. For a realistic time-dependent carbon release, a simple pulse-response description results in large predictive errors early on in the simulation. As a result, we develop a convolution-based description of atmospheric CO2 decay which significantly decreases these initial residuals. Our response function represents a simple and practical tool for rapidly projecting the atmospheric lifetime of a wide range of CO2 emission sizes, and in convolution form, can be used across a large range of rates of release, allowing it to be used in place of more complex models for assessing the long-term atmospheric CO2 perturbation following future anthropogenic emissions. Our analysis also reveals that, as the marine CO2 sinks become saturated, both the fraction of total emissions that are removed from the atmosphere via carbonate weathering and burial and the timescale of removal progressively increase. However, we find that the ultimate CO2 sink - silicate weathering feedback - is approximately invariant with respect to

  5. Elevated Omentin Serum Levels Predict Long-Term Survival in Critically Ill Patients

    PubMed Central

    Luedde, Mark; Benz, Fabian; Niedeggen, Jennifer; Vucur, Mihael; Hippe, Hans-Joerg; Spehlmann, Martina E.; Schueller, Florian; Loosen, Sven; Frey, Norbert; Trautwein, Christian; Koch, Alexander; Luedde, Tom; Tacke, Frank

    2016-01-01

    Introduction. Omentin, a recently described adipokine, was shown to be involved in the pathophysiology of inflammatory and infectious diseases. However, its role in critical illness and sepsis is currently unknown. Materials and Methods. Omentin serum concentrations were measured in 117 ICU-patients (84 with septic and 33 with nonseptic disease etiology) admitted to the medical ICU. Results were compared with 50 healthy controls. Results. Omentin serum levels of critically ill patients at admission to the ICU or after 72 hours of ICU treatment were similar compared to healthy controls. Moreover, circulating omentin levels were independent of sepsis and etiology of critical illness. Notably, serum concentrations of omentin could not be linked to concentrations of inflammatory cytokines or routinely used sepsis markers. While serum levels of omentin were not predictive for short term survival during ICU treatment, low omentin concentrations were an independent predictor of patients' overall survival. Omentin levels strongly correlated with that of other adipokines (e.g., leptin receptor or adiponectin), which have also been identified as prognostic markers in critical illness. Conclusions. Although circulating omentin levels did not differ between ICU-patients and controls, elevated omentin levels were predictive for an impaired patients' long term survival. PMID:27867249

  6. Ionospheric ion temperature climate and upper atmospheric long-term cooling

    NASA Astrophysics Data System (ADS)

    Zhang, Shun-Rong; Holt, John M.; Erickson, Philip J.; Goncharenko, Larisa P.; Nicolls, Michael J.; McCready, Mary; Kelly, John

    2016-09-01

    It is now recognized that Earth's upper atmosphere is experiencing a long-term cooling over the past several solar cycles. The potential impact of the cooling on societal activities is significant, but a fundamental scientific question exists regarding the drivers of the cooling. New observations and analyses provide crucial advances in our knowledge of these important processes. We investigate ionospheric ion temperature climatology and long-term trends using up-to-date large and consistent ground-based data sets as measured by multiple incoherent scatter radars (ISRs). The very comprehensive view provided by these unique observations of the upper atmospheric thermal status allows us to address drivers of strong cooling previously observed by ISRs. We use observations from two high-latitude sites at Sondrestrom (invariant latitude 73.2°N) from 1990 to 2015 and Chatanika/Poker Flat (invariant latitude 65.9°N) over the span of 1976-2015 (with a gap from 1983 to 2006). Results are compared to conditions at the midlatitude Millstone Hill site (invariant latitude 52.8°N) from 1968 to 2015. The aggregate radar observations have very comparable and consistent altitude dependence of long-term trends. In particular, the lower F region (<275 km) exhibits dayside cooling trends that are significantly higher (-3 to -1 K/yr at 250 km) than anticipated from model predictions given the anthropogenic increase of greenhouse gases. Above 275 km, cooling trends continue to increase in magnitude but values are strongly dependent on magnetic latitude, suggesting the presence of significant downward influences from nonneutral atmospheric processes.

  7. 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.

  8. 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.

  9. Long-term trends in atmospheric pollen levels in the city of Thessaloniki, Greece

    NASA Astrophysics Data System (ADS)

    Damialis, Athanasios; Halley, John M.; Gioulekas, Dimitrios; Vokou, Despina

    We examined the long-term trends in pollen atmospheric levels in Thessaloniki, the second largest city of Greece. On the basis of data collected during the period 1987-2005, we estimated trends in the atmospheric pollen levels for the 16 different taxa, each of whose contribution to the total atmospheric pollen concentration was at least 0.5%. We also tested for trends towards earlier, longer or more highly peaked pollen seasons. The salient feature of these data is that the levels of pollen have been increasing; this is true for the majority of the individual taxa examined (12 out of 16) and for their aggregate. On average, the atmospheric pollen concentration is doubling every decade, but for some species the rate is much higher, with doubling times less than 5 years. Among the taxa with the highest rate of long-term trend in atmospheric pollen concentration, four belong to the group of woody plants (Cupressaceae, Quercus, Platanus, Pinaceae) and only one to that of herbs (Urticaceae). For the pollen-season-related attributes (onset, peak, end and duration), there was no systematic tendency and the changes were more nuanced. The observed increase in pollen abundance coincides with a rise in air temperature, which is the only meteorological factor to have experienced a sustained and significant change over the same period in Thessaloniki. Our results suggest that changes in pollen distributions are dominated by increases in pollen production rather than changes in flowering phenology and that several species showing strong trends might serve as bio-indicators of expected climate change. Given that the pollen-producing reservoir around the city has not increased, these results provide further evidence of the impact of climate change on plant biota.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. Long-Term Intermittent Exposure to High Altitude Elevates Asymmetric Dimethylarginine in First Exposed Young Adults.

    PubMed

    Lüneburg, Nicole; Siques, Patricia; Brito, Julio; De La Cruz, Juan José; León-Velarde, Fabiola; Hannemann, Juliane; Ibanez, Cristian; Böger, Rainer H

    2017-09-01

    Lüneburg, Nicole, Patricia Siques, Julio Brito, Juan José De La Cruz, Fabiola León-Velarde, Juliane Hannemann, Cristian Ibanez, and Rainer Böger. Long-term intermittent exposure to high altitude elevates asymmetric dimethylarginine in first exposed young adults. High Alt Med Biol. 18:226-233, 2017.-Hypoxia-induced dysregulation of pulmonary and cerebral circulation may be related to an impaired nitric oxide (NO) pathway. We investigated the effect of chronic intermittent hypobaric hypoxia (CIH) on metabolites of the NO pathway. We measured asymmetric and symmetric dimethylarginine (ADMA and SDMA) and monomethyl-L-arginine (L-NMMA) and assessed their associations with acclimatization in male draftees (n = 72) undergoing CIH shifts at altitude (3550 m) during 3 months. Sixteen Andean natives living at altitude (3675 m) (chronic hypobaric hypoxia [CH]) were included for comparison. In CIH, ADMA and L-NMMA plasma concentrations increased from 1.14 ± 0.04 to 1.95 ± 0.09 μmol/L (mean ± SE) and from 0.22 ± 0.07 to 0.39 ± 0.03 μmol/L, respectively, (p < 0.001 for both) after 3 months, whereas SDMA did not change. The concentrations of ADMA and L-NMMA were higher in CH (3.48 ± 0.07, 0.53 ± 0.08 μmol/L; p < 0.001) as compared with CIH. In both CIH and CH, ADMA correlated with hematocrit (r(2) = 0.07, p < 0.05; r(2) = 0.26; p < 0.01). In CIH, an association of ADMA levels with poor acclimatization status was observed. We conclude that the endogenous NO synthase inhibitors, ADMA and L-NMMA, are elevated in hypoxia. This may contribute to impaired NO production at altitude and may also be predictive of altitude-associated health impairment.

  15. Effects of long-term elevated temperature on covering, sheltering and righting behaviors of the sea urchin Strongylocentrotus intermedius.

    PubMed

    Zhang, Lisheng; Zhang, Lingling; Shi, Dongtao; Wei, Jing; Chang, Yaqing; Zhao, Chong

    2017-01-01

    Increases in ocean temperature due to climate change are predicted to change the behaviors of marine invertebrates. Altered behaviors of keystone ecosystem engineers such as echinoderms will have consequences for the fitness of individuals, which are expected to flow on to the local ecosystem. Relatively few studies have investigated the behavioral responses of echinoderms to long-term elevated temperature. We investigated the effects of exposure to long-term (∼31 weeks) elevated temperature (∼3 °C above the ambient water temperature) on covering, sheltering and righting behaviors of the sea urchin Strongylocentrotus intermedius. Long-term elevated temperature showed different effects on the three behaviors. It significantly decreased covering behavior, including both covering behavior reaction (time to first covering) and ability (number of covered sea urchins and number of shells used for covering). Conversely, exposure to long-term elevated temperature significantly increased sheltering behavior. Righting response in S. intermedius was not significantly different between temperature treatments. The results provide new information into behavioral responses of echinoderms to ocean warming.

  16. Effects of long-term elevated temperature on covering, sheltering and righting behaviors of the sea urchin Strongylocentrotus intermedius

    PubMed Central

    Zhang, Lisheng; Zhang, Lingling; Shi, Dongtao; Wei, Jing; Chang, Yaqing

    2017-01-01

    Increases in ocean temperature due to climate change are predicted to change the behaviors of marine invertebrates. Altered behaviors of keystone ecosystem engineers such as echinoderms will have consequences for the fitness of individuals, which are expected to flow on to the local ecosystem. Relatively few studies have investigated the behavioral responses of echinoderms to long-term elevated temperature. We investigated the effects of exposure to long-term (∼31 weeks) elevated temperature (∼3 °C above the ambient water temperature) on covering, sheltering and righting behaviors of the sea urchin Strongylocentrotus intermedius. Long-term elevated temperature showed different effects on the three behaviors. It significantly decreased covering behavior, including both covering behavior reaction (time to first covering) and ability (number of covered sea urchins and number of shells used for covering). Conversely, exposure to long-term elevated temperature significantly increased sheltering behavior. Righting response in S. intermedius was not significantly different between temperature treatments. The results provide new information into behavioral responses of echinoderms to ocean warming. PMID:28348933

  17. Long-term Decline of Global Atmospheric Ethane Concentrations and Implications for Methane

    NASA Astrophysics Data System (ADS)

    Blake, D. R.; Simpson, I. J.; Sulbaek Andersen, M.; Meinardi, S.; Bruhwiler, L.; Blake, N. J.; Helmig, D.

    2012-12-01

    Methane (CH4) and ethane (C2H6) are the most abundant hydrocarbons in the remote atmosphere. Both are precursors to tropospheric ozone (O3) and methane is a potent greenhouse gas. 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 Tg yr-1, or 21% from 1984-2010. Based on simulations using the TM5 atmospheric tracer transport model, ethane's long-term global decline is attributed to decreasing fugitive emissions from ethane's fossil fuel source—most likely reduced venting and flaring of natural gas in oil fields—rather than declines in its other major sources, biofuel use and biomass burning. In addition, our calculated top-down estimates of ethane's global emission rates agree well with recent bottom-up estimates from the literature, which suggests that the ethane budget is quite well balanced and unlikely to have any additional major sources. 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 growth rate to slow (Aydin et al., 2011; Kai et al., 2011). Because methane and ethane are emitted from fossil fuel sources with characteristic emission ratios, our long-term ethane record can be used to quantitatively investigate methane's slowing growth rate. We show that reduced fugitive fossil fuel emissions account for at least 10-21 Tg yr-1 (30-70%) of the decrease in methane's global emissions, significantly contributing to methane's slowing growth rate since the mid-1980s.

  18. Uncertainty in Long-Term Atmospheric Data Records from MSU and AMSU

    NASA Astrophysics Data System (ADS)

    Mears, C. A.

    2015-12-01

    The temperature of the Earth's atmosphere has been continuously observed by satellite-borne microwave sounders since late 1978. These measurements, made by the Microwave Sounding Units (MSUs) and the Advanced Microwave Sounding Units (AMSUs) yield one of the longest truly global records of Earth's climate. To be useful for climate studies, measurements made by different satellites and satellite systems need to be merged into a single long-term dataset. Before and during the merging process, a number of adjustments made to the satellite measurements. These adjustments are intended to account for issues such as calibration drifts or changes in local measurement time. Because the adjustments are made with imperfect knowledge, they are therefore not likely to reduce errors to zero, and thus introduce uncertainty into the resulting long-term data record. In this presentation, we will discuss a Monte-Carlo-based approach to calculating and describing the effects of these uncertainty sources on the final merged dataset. The result of our uncertainty analysis is an ensemble of possible datasets, with the applied adjustments varied within reasonable bounds, and other error sources such as sampling noise taken into account. The ensemble approach makes it easy for the user community to assess the effects of uncertainty on their work by simply repeating their analysis for each ensemble member.

  19. Long-Term Operation Of Ground-Based Atmospheric Sensing Systems In The Tropical Western Pacific

    SciTech Connect

    Ivey, Mark; Jones, Larry J.; Porch, W. M.; Apple, Monty L.; Widener, Kevin B.

    2004-10-14

    Three semi-autonomous atmospheric sensing systems were installed in the tropical western Pacific region. The first of these Atmospheric Radiation and Cloud Stations (ARCS) began operation in 1996. Each ARCS is configured as a system-of-systems since it comprises an ensemble of independent instrument systems. The ARCS collect, process, and transmit large volumes of cloud, solar and thermal radiation, and meteorological data to support climate studies and climate-modeling improvements as part of the U.S Department of Energy’s Atmospheric and Radiation Measurement (ARM) Program. Data from these tropical ARCS stations have been used for satellite ground-truth data comparisons and validations, including comparisons for MTI and AQUA satellite data. Our experiences with these systems in the tropics led to modifications in their design. An ongoing international logistics effort is required to keep gigabytes per day of quality-assured data flowing to the ARM program’s archives. Design criteria, performance, communications methods, and the day-to-day logistics required to support long-term operations of ground-based remote atmospheric sensing systems are discussed. End-to-end data flow from the ARCS systems to the ARM Program archives is discussed.

  20. 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

  1. 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

  2. Long-term atmospheric effects of medium-energy electron precipitation from chemistry-climate modelling

    NASA Astrophysics Data System (ADS)

    Andersson, M. E.; Verronen, P. T.; Marsh, D. R.; Seppälä, A.; Kalakoski, N.

    2016-12-01

    Medium energy electrons (MEE) from the Earth's outer radiation belt continuously affects the chemical composition of the mesosphere. In particular, ionisation caused by MEE leads to the production of odd hydrogen and odd nitrogen species that affects ozone chemistry. By absorbing a great part of UV radiation, ozone plays an important role in the energy budget and dynamics of the middle atmosphere. During strong precipitation events lasting days, ozone has been observed to decrease by tens of percent in the wintertime polar region. Such ozone perturbation causes zonal wind anomalies through wave-mean flow interaction which propagate to lower altitudes during the polar winter and affect stratospheric temperature. However, understanding the long term effects from MEE and its potential role in the polar climate variability is a difficult task due to the limitations of the satellite measurements. Here we use the Whole Atmosphere Community Climate Model (WACCM) together with MEE flux characterised using a precipitation model driven by the magnetic Ap index to simulate the effects of MEE on the solar cycles time scale. We will present results from free running simulations for the period of time 1955-2005. We will contrast our results with those from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) in order to assess the role of MEE and its significance to the atmospheric dynamics and climate variability in the polar regions.

  3. 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.

  4. 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.

  5. Long-term measurement of daytime atmospheric mixing layer height over Hong Kong

    NASA Astrophysics Data System (ADS)

    Yang, Dongwei; Li, Chengcai; Lau, Alexis Kai-Hon; Li, Ying

    2013-03-01

    Lidar has unique advantages in temporal and spatial resolution to measure the atmospheric mixing layer height (MLH), which is important for analyzing atmospheric phenomena. However, long-term MLH information over several years, which has important significance in air quality and climate studies, is seldom obtained from lidar data due to the scarcity of long-running lidar observations. In this paper, we retrieve and analyze daytime MLH from a data set of a lidar that operated continuously over 6.5 years at Yuen Long, Hong Kong. A new algorithm has been developed for consistently retrieving MLH from this large data set, handling all possible weather conditions and aerosol layer structures. We analyze the diurnal, seasonal and inter-annual variation of MLH over Hong Kong and find a unique phenomenon that the afternoon MLH is higher in autumn than in summer, which is verified by radiosonde results and explained by thermal stability and humidity effect. Moreover, we find a slightly decreasing trend of the daily maximum of MLH, which implies a continually compressed air volume into which pollutants and their precursors are emitted, which is one of the possible factors leading to deteriorated air quality over Hong Kong region.

  6. 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

  7. 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

  8. Atmospheric oscillations comparison on long term tropospheric delay time series derived from ray-tracing and GPS

    NASA Astrophysics Data System (ADS)

    Nikolaidou, Thalia; Santos, Marcelo

    2017-04-01

    The caused time delay induced by the atmosphere on the GNSS signals (NAD), depends primarily on the amount of atmosphere the signal traverses till it reaches to the Earth's surface and can exceed t 20 m for low elevation angles (around 3 degrees). For a particular ray i.e. satellite/quasar-antenna link, the delay depends on the atmospheric parameters of total pressure, temperature, and the partial pressure of water vapor. Because of that, numerical weather models (NWM) have already proven beneficial for atmospheric modelling and geodesy. By direct raytracing, inside NWM, the VMF1 and the University of New Brunswick VMF1 (UNB-VMF1) (Urquhart et al. 2011), access the 3D variation of the meteorological parameters that determine the delay thus being the state-the-art mapping functions used today. The raytracing procedure is capable of providing NADs delays for any point on the Earth's surface. In this study we study the impact of regional numerical weather models, with high spatial and temporal resolution, namely 25km and 6h. These models outweigh the currently used NWM by having about 2.6 times better spatial resolution. Raytracing through such NWM, using the independent raytracing algorithm develop at UNB (Nievinski, 2009), we acquire superior quality NADs with regional application. We ray-trace for the International GNSS service (IGS) network stations for a time span of 11 years. Benchmarking against the IGS troposphere product is performed to access the accuracy of our results. A periodicity analysis is conducted to examine the signature of atmospheric oscillations on the NAD time series. In order to recognize the NAD periodicities, we compared our product against the GPS-derived IGS troposphere product. Systematic effects within each single technique are identified and long-term NAD stability is accessed.

  9. Mesoscale atmospheric modelling technology as a tool for the long-term meteorological dataset development

    NASA Astrophysics Data System (ADS)

    Platonov, Vladimir; Kislov, Alexander; Rivin, Gdaly; Varentsov, Mikhail; Rozinkina, Inna; Nikitin, Mikhail; Chumakov, Mikhail

    2017-04-01

    The detailed hydrodynamic modelling of meteorological parameters during the last 30 years (1985 - 2014) was performed for the Okhotsk Sea and the Sakhalin island regions. The regional non-hydrostatic atmospheric model COSMO-CLM used for this long-term simulation with 13.2, 6.6 and 2.2 km horizontal resolutions. The main objective of creation this dataset was the outlook of the investigation of statistical characteristics and the physical mechanisms of extreme weather events (primarily, wind speed extremes) on the small spatio-temporal scales. COSMO-CLM is the climate version of the well-known mesoscale COSMO model, including some modifications and extensions adapting to the long-term numerical experiments. The downscaling technique was realized and developed for the long-term simulations with three consequent nesting domains. ERA-Interim reanalysis ( 0.75 degrees resolution) used as global forcing data for the starting domain ( 13.2 km horizontal resolution), then these simulation data used as initial and boundary conditions for the next model runs over the domain with 6.6 km resolution, and similarly, for the next step to 2.2 km domain. Besides, the COSMO-CLM model configuration for 13.2 km run included the spectral nudging technique, i.e. an additional assimilation of reanalysis data not only at boundaries, but also inside the whole domain. Practically, this computational scheme realized on the SGI Altix 4700 supercomputer system in the Main Computer Center of Roshydromet and used 2,400 hours of CPU time total. According to modelling results, the verification of the obtained dataset was performed on the observation data. Estimations showed the mean error -0.5 0C, up to 2 - 3 0C RMSE in temperature, and overestimation in wind speed (RMSE is up to 2 m/s). Overall, analysis showed that the used downscaling technique with applying the COSMO-CLM model reproduced the meteorological conditions, spatial distribution, seasonal and synoptic variability of temperature and

  10. Atmospheric nitrogen deposition and its long-term dynamics in a southeast China coastal area.

    PubMed

    Chen, Nengwang; Hong, Huasheng; Huang, Quanjia; Wu, Jiezhong

    2011-06-01

    Measurements were conducted during 2004-2005 and 2009-2010 to characterize atmospheric nitrogen (N) deposition to the Jiulong River Estuary - Xiamen Bay area in southeast China. Isotopic analysis and long-term data (1990-2009) for inorganic N extracted from the national acid deposition dataset were used to determine the dominant source of atmospheric nitrate and N component dynamics. The results showed that the mean dissolved total N concentration in rain water for the three coastal area sites was 2.71 ± 1.58 mg N L(-1) (n = 141) in 2004. The mean dissolved inorganic N at the Xiamen site was 1.62 ± 1.19 mg N L(-1) (n = 46) in 2004-2005 and 1.56 ± 1.39 mg N L(-1) (n = 36) in 2009-2010, although the difference is not significant, nitrate turnover dominates the N component in the latter period. Total deposition flux over Xiamen was 30 kg N ha(-1) yr(-1), of which dry and wet deposition contributed 16% and 84%, respectively. Nitrate in wet deposition with low isotopic value (between -3.05 and -7.48‰) was likely to have mostly originated from combustion NO(x) from vehicle exhausts. The inorganic N in acid deposition exhibited a significant increase (mainly for nitrate) since the mid-1990s, which is consistent with the increased gaseous concentrations of NO(x) and expanding number of automobiles in the coastal city (Xiamen). The time series of nitrate anions and ammonium cations as well as pH values during the period 1990-2009 reflected an increasing trend of N emission with potential implication for N-induced acidification. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. 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

  12. Long-term record of atmospheric and snow surface nitrate from Dome C (Central Antarctica)

    NASA Astrophysics Data System (ADS)

    Traversi, Rita; Becagli, Silvia; Brogioni, Marco; Caiazzo, Laura; Ciardini, Virginia; Giardi, Fabio; Legrand, Michel; Macelloni, Giovanni; Petkov, Boyan; Preunkert, Suzanne; Scarchilli, Claudio; Severi, Mirko; Vitale, Vito; Udisti, Roberto

    2017-04-01

    Nitrate is the end product of the oxidation of atmospheric nitrogen oxides and one of the most abundant ions present in polar ice and snow, mainly as nitric acid in present-climate conditions. Nitrate stratigraphies from snow and ice layers have the potential to provide records of past changes in atmospheric composition, including atmospheric NOx cycling and oxidative capacity, as well as past solar activity or major variations in Earth's magnetic field. Nevertheless, in order to exploit such a potential, chemical concentrations in the air, snow, firn and ice core need to be correlated. Hence, the knowledge of the link between atmosphere and snow composition at the time of deposition is basic to reconstruct past climate and past atmospheric chemical composition. The extent of such knowledge depends on whether the species of interest are gaseous or in the condensed phase, and if they are reversible and/or irreversibly deposited to snow. In order to provide a contribution to their air-to-snow exchange in the Antarctic plateau, as well as to the understanding of dominant sources and sinks of nitrate, we present here nitrate records in atmospheric aerosol and surface snow sampled at high resolution, all year-round, at Dome C along 9 years (November 2004 - November 2013). This represents the longest and most highly resolved record from continental Antarctica, where continuous and long-term atmosphere and snow samplings are particularly difficult due to the extreme meteorological conditions and, at the same time, need of extra-care in avoiding contamination due to the low level of ion concentrations. Results confirm, on a larger statistical data set with respect to previous observations, nitrate seasonal pattern with summer maxima both for aerosol and surface snow, in-phase with UV solar irradiance. Such a temporal pattern is likely a combination of nitrate sources and post-depositional processes that enhance during summer. Moreover, a case study of synoptic analysis for

  13. Assessment of effects of the rising atmospheric nitrogen deposition on nitrogen uptake and long-term water-use efficiency of plants using nitrogen and carbon stable isotopes.

    PubMed

    Yao, F Y; Wang, G A; Liu, X J; Song, L

    2011-07-15

    This study assesses the effects of the atmospheric nitrogen (N) deposition on the N uptake and the long-term water-use efficiency of two C(3) plants (Agropyron cristatum and Leymus chinensis) and two C(4) plants (Amaranthus retroflexus and Setaria viridis) using N and C stable isotopes. In addition, this study explores the potential correlation between leaf N isotope (δ(15)N) values and leaf C isotope (δ(13)C) values. This experiment shows that the atmospheric N deposition has significant effects on the N uptake, δ(15)N and leaf N content (N(m)) of C(3) plants. As the atmospheric N deposition rises, the proportion and the amount of N absorbed from the simulated atmospheric deposition become higher, and the δ(15)N and N(m) of the two C(3) plants both also increase, suggesting that the rising atmospheric N deposition is beneficial for C(3) plants. However, C(4) plants display different patterns in their N uptake and in their variations of δ(15)N and N(m) from those of C(3) plants. C(4) plants absorb less N from the atmospheric deposition, and the leaf N(m) does not change with the elevated atmospheric N deposition. Photosynthetic pathways may account for the differences between C(3) and C(4) plants. This study also shows that atmospheric N deposition does not play a role in determining the δ(13)C and in the long-term water-use efficiency of C(3) and C(4) plants, suggesting that the long-term water-use pattern of the plants does not change with the atmospheric N input. In addition, this study does not observe any relationship between leaf δ(15)N and leaf δ(13)C in both C(3) and C(4) plants.

  14. 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.

  15. 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

  16. Interannual Variability and Long-Term Changes of Atmospheric Circulationover the Chukchi-Beaufort Seas

    NASA Astrophysics Data System (ADS)

    Wu, Qigang; Zhang, Jing; Zhang, Xiangdong

    2013-04-01

    Recent studies have documented many features of the Beaufort Sea High (BSH), including seasonal cycle, temporal variability based on a BSH strength index, and a trend towards a stronger summer BSH that began in the late 1990s. In this study, we will further examine the variability and long-term trends of atmospheric circulation over the Chukchi-Beaufort Seas and northern Alaska using ERA Interim Reanalysis for the period of 1979-2012. To capture the moving feature of the BSH, the EOF analysis is applied to sea level pressure (SLP) field in the Chukchi-Beaufort Seas to investigate the principal patterns of the BSH variability for seasons of springtime (Apr.-May), summertime (Jun.-Aug.), autumn (Sep.-Oct.), and wintertime (Nov.-Mar.). In each season, the leading three EOF modes explain near 90% of the total variance, reflect a wintertime-like strengthened or weakened BSH centered over the western Arctic Ocean (EOF1), north-south dipole-like SLP anomalies (EOF2), and west-east dipole-like SLP anomalies (EOF3) respectively. The correlations are -0.83 between the PC time series of EOF1 (PC1) and the index of the Northern Annular Mode (NAM) in JJA, and -0.88 (0.57) between the PC 1 (PC2) of the EOF1 (EOF2) and the index of the North Pacific Oscillation (Pacific-North American) teleconnection pattern during Nov.-Mar., indicating that there are extensive controls of the BSH by the large-scale climate modes. Both PC2 associated with EOF2 in JJA and SO have exhibited a significant tendency toward high index polarity at the 10% level over the past few decades, are related to strongly reduced Arctic sea ice extent in summer and autumn. In the study period, we also detected significant anticyclonic trends of surface wind fields associated with a strengthened BSH during summer (JJA) and autumn (SO), and significant cyclonic trends of surface wind fields associated with a weakened BSH during early-middle winter (November to January). Such changes in atmospheric circulation from

  17. 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

  18. Reestablishing natural succession on acidic mine spoils at high elevations: long-term ecological restoration

    Treesearch

    Ray W. Brown; Michael C. Amacher; Walter F. Mueggler; Janice Kotuby-Amacher

    2003-01-01

    Methods for restoring native plant communities on acidic mine spoils at high elevations were evaluated in a "demonstration area" in the New World Mining District of southern Montana. Research plots installed in 1976 were assessed for 22 years and compared with adjacent native reference plant communities. A 1.5-acre (0.61-ha) area of mine spoils was shaped and...

  19. Some biochemical and pathophysiological aspects of long-term elevation of brain ornithine concentrations.

    PubMed

    Daune-Anglard, G; Bonaventure, N; Seiler, N

    1993-07-01

    Mice and chicken were given 5-fluoromethylornithine (5FMOrn), a selective inactivator of ornithine aminotransferase (OAT) over extended periods of time. This treatment allowed us to maintain elevated concentrations of ornithine in all tissues. Since gyrate atrophy, an autosomal recessive human disease, is characterized by the absence of OAT, special emphasis was put on the study of the visual system. Ophthalmoscopic and histologic examinations of the eye as well as electroretinograms and locomotor behaviour demonstrated an unimpaired visual system and brain. No toxic effects were observable in the treated mice. Likewise, chick embryo development was normal in spite of highly elevated brain and tissue ornithine concentrations. A likely explanation for the absence of toxic effects of 5FMOrn treatment, disregarding the non-toxicity of ornithine, is the fact that 10-20% of tissue OAT is refractory to inactivation by 5FMOrn. This residual activity may be sufficient to maintain vital functions.

  20. Serum creatinine elevation after renin-angiotensin system blockade and long term cardiorenal risks: cohort study

    PubMed Central

    Mansfield, Kathryn E; Bhaskaran, Krishnan; Nitsch, Dorothea; Sørensen, Henrik Toft; Smeeth, Liam; Tomlinson, Laurie A

    2017-01-01

    Objective To examine long term cardiorenal outcomes associated with increased concentrations of creatinine after the start of angiotensin converting enzyme inhibitor/angiotensin receptor blocker treatment. Design Population based cohort study using electronic health records from the Clinical Practice Research Datalink and Hospital Episode Statistics. Setting UK primary care, 1997-2014. Participants Patients starting treatment with angiotensin converting enzyme inhibitors or angiotensin receptor blockers (n=122 363). Main outcome measures Poisson regression was used to compare rates of end stage renal disease, myocardial infarction, heart failure, and death among patients with creatinine increases of 30% or more after starting treatment against those without such increases, and for each 10% increase in creatinine. Analyses were adjusted for age, sex, calendar period, socioeconomic status, lifestyle factors, chronic kidney disease, diabetes, cardiovascular comorbidities, and use of other antihypertensive drugs and non-steroidal anti-inflammatory drugs. Results Among the 2078 (1.7%) patients with creatinine increases of 30% or more, a higher proportion were female, were elderly, had cardiorenal comorbidity, and used non-steroidal anti-inflammatory drugs, loop diuretics, or potassium sparing diuretics. Creatinine increases of 30% or more were associated with an increased adjusted incidence rate ratio for all outcomes, compared with increases of less than 30%: 3.43 (95% confidence interval 2.40 to 4.91) for end stage renal disease, 1.46 (1.16 to 1.84) for myocardial infarction, 1.37 (1.14 to 1.65) for heart failure, and 1.84 (1.65 to 2.05) for death. The detailed categorisation of increases in creatinine concentrations (<10%, 10-19%, 20-29%, 30-39%, and ≥40%) showed a graduated relation for all outcomes (all P values for trends <0.001). Notably, creatinine increases of less than 30% were also associated with increased incidence rate ratios for all outcomes

  1. 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

  2. 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.

  3. Transgenerational effects of global environmental change: long-term CO(2) and nitrogen treatments influence offspring growth response to elevated CO(2).

    PubMed

    Lau, Jennifer A; Peiffer, Jill; Reich, Peter B; Tiffin, Peter

    2008-11-01

    Global environmental changes can have immediate impacts on plant growth, physiology, and phenology. Long-term effects that are only observable after one or more generations are also likely to occur. These transgenerational effects can result either from maternal environmental effects or from evolutionary responses to novel selection pressures and are important because they may alter the ultimate ecological impact of the environmental change. Here, we show that transgenerational effects of atmospheric carbon dioxide (CO(2)) and soil nitrogen (N) treatments influence the magnitude of plant growth responses to elevated CO(2) (eCO(2)). We collected seeds from Lupinus perennis, Poa pratensis, and Schizachyrium scoparium populations that had experienced five growing seasons of ambient CO(2) (aCO(2)) or eCO(2) treatments and ambient or increased N deposition and planted these seeds into aCO(2) or eCO(2) environments. We found that the offspring eCO(2) treatments stimulated immediate increases in L. perennis and P. pratensis growth and that the maternal CO(2) environment influenced the magnitude of this growth response for L. perennis: biomass responses of offspring from the eCO(2) maternal treatments were only 54% that of the offspring from the aCO(2) maternal treatments. Similar trends were observed for P. pratensis and S. scoparium. We detected some evidence that long-term N treatments also altered growth responses to eCO(2); offspring reared from seed from maternal N-addition treatments tended to show greater positive growth responses to eCO(2) than offspring from ambient N maternal treatments. However, the effects of long-term N treatments on offspring survival showed the opposite pattern. Combined, our results suggest that transgenerational effects of eCO(2) and N-addition may influence the growth stimulation effects of eCO(2), potentially altering the long-term impacts of eCO(2) on plant populations.

  4. Among-provence variability of gas exchange and growth in response to long-term elevated CO2 exposure

    Treesearch

    James L.J. Houpis; Paul D. Anderson; James C. Pushnik; David J. Anschel

    1999-01-01

    Genetic variability can have profound effects on the interpretation of results from elevated CO2 studies, and future forest management decisions. Information on which varieties are best suited to future atmospheric conditions is needed to develop future forest management practices. A large-scale screening study of the effects of elevated CO

  5. Long Term Elevation Change of the Antarctic Ice Sheet from Multi-Mission Satellite Altimetry

    NASA Astrophysics Data System (ADS)

    Schroeder, L.; Horwath, M.; Dietrich, R. O. R.; Scheinert, M.; Ligtenberg, S.; van den Broeke, M. R.

    2016-12-01

    Compared to mountain glaciers or the Greenland ice sheet, only small parts of the Antarctic ice sheet show a significant reaction to climate change. However, due to its large dimension also very small changes of the remaining ice body, especially in East Antarctica, can have a big influence on the total mass balance. Such small changes very often do not reach a significant level within a single satellite altimeter mission. Therefor we apply a multi-mission approach to extend the time span to 25 years. We show how a consistent reprocessing of altimeter data from different missions can improve the accuracy and precision of conventional pulse limited radar altimetry by about 30%. Together with ICESat we can use this coherent set of radar data to derive elevation changes over 25 years. The high accuracy laser altimeter measurements of ICESat are used to constrain the offsets due to the radar penetration and make the measurements comparable. The high density of CryoSat-2 data allows to obtain a real resolution of 1 km almost without interpolation. ERS-1, ERS-2, Envisat and Saral provide quasi-continuous measurements along the same repeat orbit and thus a long and stable time series. The results are validated by the measurements of ICEBridge airborne altimetry and long range kinematic GNSS profiles. Finally, the elevation changes are converted into mass changes using the output of a regional climate model.

  6. 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

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

    PubMed Central

    Pravosudov, Vladimir V

    2003-01-01

    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

  8. Long-term stable vertical bone regeneration after sinus floor elevation and simultaneous implant placement with and without grafting.

    PubMed

    Verdugo, Fernando; Uribarri, Agurne; Laksmana, Theresia; D'addona, Antonio

    2017-09-21

    Less invasive surgical approaches to regenerate bone intra-sinus and allow long-term functional implant stability are needed. To evaluate long-term vertical bone regeneration after sinus floor elevation and simultaneous implant placement with and without bone grafting. Vertical bone gains (VBG) post-sinus elevation, with and without grafting, were evaluated in thirty individuals presenting an average residual bone height (RBH) of 4.2 mm using a standardized digital technique. Measurements were taken preoperatively, and at an average of 64.6 months follow-up. Clinically, peri-implant tissues were assessed for pocket formation and presence of inflammation to evaluate established success criteria. Overall, RBH averaged 4.2 ± 1.1 mm (range: 1.8-5.8) and VBG 7.7 ± 1.6 mm (range: 6.0-12.9). Mean difference of 7.6 mm between vertical bone heights (VBH) at augmented implants sites and initial RBH, 11.8 versus 4.2 mm, (P < .0001, CI95%: 6.9-8.2) was statistically significant. RBH averaged 4.5 ± 0.8 mm and 3.8 ± 1.2 (P = .07) and VBG 6.8 ± 0.5 and 8.5 ± 1.9 mm (P = .003, CI95%: 0.6-2.7), for nongrafted and grafted individuals, respectively. The grafting group received an average graft volume of 0.35 ± 0.1 cc (range: 0.25-0.5) per implant site. Long-term follow-ups average 64.6 months (range: 36-144) and all implants met the success criteria. VBG ≥ 7 mm were 7.3 times more likely to develop on grafted sites (OR = 7.3, P = 0.02, CI95%: 1.2-46.2). None to negligible amounts of grafting material are required to regenerate substantial amounts of autogenous bone into atrophic sinus cavities after simultaneous implant placement. The regenerated VBH seems stable for functional implant stability long-term. Implant success rates were 100% at an average of 64.6 months. © 2017 Wiley Periodicals, Inc.

  9. 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

  10. 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.

  11. Dense lower crust elevates long-term earthquake rates in the New Madrid seismic zone

    NASA Astrophysics Data System (ADS)

    Levandowski, Will; Boyd, Oliver S.; Ramirez-Guzmán, Leonardo

    2016-08-01

    Knowledge of the local state of stress is critical in appraising intraplate seismic hazard. Inverting earthquake moment tensors, we demonstrate that principal stress directions in the New Madrid seismic zone (NMSZ) differ significantly from those in the surrounding region. Faults in the NMSZ that are incompatible with slip in the regional stress field are favorably oriented relative to local stress. We jointly analyze seismic velocity, gravity, and topography to develop a 3-D crustal and upper mantle density model, revealing uniquely dense lower crust beneath the NMSZ. Finite element simulations then estimate the stress tensor due to gravitational body forces, which sums with regional stress. The anomalous lower crust both elevates gravity-derived stress at seismogenic depths in the NMSZ and rotates it to interfere more constructively with far-field stress, producing a regionally maximal deviatoric stress coincident with the highest concentration of modern seismicity. Moreover, predicted principal stress directions mirror variations (observed independently in moment tensors) at the NMSZ and across the region.

  12. Dense lower crust elevates long-term earthquake rates in the New Madrid seismic zone

    USGS Publications Warehouse

    Levandowski, William Brower; Boyd, Oliver; Ramirez-Guzman, Leonardo

    2016-01-01

    Knowledge of the local state of stress is critical in appraising intraplate seismic hazard. Inverting earthquake moment tensors, we demonstrate that principal stress directions in the New Madrid seismic zone (NMSZ) differ significantly from those in the surrounding region. Faults in the NMSZ that are incompatible with slip in the regional stress field are favorably oriented relative to local stress. We jointly analyze seismic velocity, gravity, and topography to develop a 3-D crustal and upper mantle density model, revealing uniquely dense lower crust beneath the NMSZ. Finite element simulations then estimate the stress tensor due to gravitational body forces, which sums with regional stress. The anomalous lower crust both elevates gravity-derived stress at seismogenic depths in the NMSZ and rotates it to interfere more constructively with far-field stress, producing a regionally maximal deviatoric stress coincident with the highest concentration of modern seismicity. Moreover, predicted principal stress directions mirror variations (observed independently in moment tensors) at the NMSZ and across the region.

  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.

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

    PubMed

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

    2015-09-01

    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. 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. 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. 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. © 2015 The Authors.

  15. 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. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  16. 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

  17. Comparison of long-term mortality of acute ST-segment elevation myocardial infarction and non-ST-segment elevation acute coronary syndrome patients after percutaneous coronary intervention

    PubMed Central

    Ren, Lihui; Ye, Huiming; Wang, Ping; Cui, Yuxia; Cao, Shichang; Lv, Shuzheng

    2014-01-01

    Background and aims: This study is to compare the short-term and long-term mortality in patients with ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation acute coronary syndrome (NSTE-ACS) after percutaneous coronary intervention (PCI). Methods and results: A total of 266 STEMI patients and 140 NSTE-ACS patients received PCI. Patients were followed up by telephone or at medical record or case statistics center and were followed up for 4 years. Descriptive statistics and multivariate survival analyses were employed to compare the mortality in STEMI and NSTE-ACS. All statistical analyses were performed by SPSS19.0 software package. NSTE-ACS patients had significantly higher clinical and angiographic risk profiles at baseline. During the 4-year follow-up, all-cause mortality in STEMI was significantly higher than that in NSTE-ACS after coronary stent placement (HR 1.496, 95% CI 1.019-2.197). In a landmark analysis no difference was seen in all-cause mortality for both STEMI and NSTE-ACS between 6 month and 4 years of follow-up (HR 1.173, 95% CI 0.758-1.813). Conclusions: Patients with STEMI have a worse long-term prognosis compared to patients with NSTE-ACS after PCI, due to higher short-term mortality. However, NSTE-ACS patients have a worse long-term survival after 6 months. PMID:25664077

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

    DOE PAGES

    Eberhardt, Thomas L.; Labbé, Nicole; So, Chi-Leung; ...

    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

  19. Anxiolytic effects of short- and long-term administration of cacao mass on rat elevated T-maze test.

    PubMed

    Yamada, Takashi; Yamada, Yasushi; Okano, Yasuyo; Terashima, Takehiko; Yokogoshi, Hidehiko

    2009-12-01

    We demonstrated the effects of short- and long-term administration of cacao mass on anxiety in the elevated T-maze test, which is an animal model of anxiety. In the first study, we administered cacao mass (100 mg/100 g body weight) per os and immediately performed the elevated T-maze test. Short-term cacao mass significantly abolished delayed avoidance latency compared with the control but did not change escape latency. This result suggested that cacao mass administration reduced conditional fear-relating behavior. Short-term cacao mass administration did not affect the concentration of brain monoamines, emotion-related neurotransmitters such as norepinephrine, serotonin and dopamine, in the rat brain. In the next study, we fed a cacao mass-containing diet to rats for 2 weeks and performed the elevated T-maze test. Contrary to short-term administration, chronic consumption of cacao mass tended to increase avoidance latency and did not change escape latency. Brain serotonin concentration and its turnover were enhanced by chronic consumption of cacao mass. These results suggested that chronic consumption of cacao did not affect fear-related behavior but was involved in brain monoamine metabolism. In conclusion, we suggest that short-term cacao mass consumption showed an anxiolytic effect but chronic consumption did not.

  20. 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.

  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.

  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. 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.

  4. Direct and legacy effects of long-term elevated CO₂ on fine root growth and plant-insect interactions.

    PubMed

    Stiling, Peter; Moon, Daniel; Rossi, Anthony; Forkner, Rebecca; Hungate, Bruce A; Day, Frank P; Schroeder, Rachel E; Drake, Bert

    2013-11-01

    Increasing atmospheric CO₂ concentrations alter leaf physiology, with effects that cascade to communities and ecosystems. Yet, responses over cycles of disturbance and recovery are not well known, because most experiments span limited ecological time. We examined the effects of CO₂ on root growth, herbivory and arthropod biodiversity in a woodland from 1996 to 2006, and the legacy of CO₂ enrichment on these processes during the year after the CO₂ treatment ceased. We used minirhizotrons to study root growth, leaf censuses to study herbivory and pitfall traps to determine the effects of elevated CO₂ on arthropod biodiversity. Elevated CO₂ increased fine root biomass, but decreased foliar nitrogen and herbivory on all plant species. Insect biodiversity was unchanged in elevated CO₂. Legacy effects of elevated CO₂ disappeared quickly as fine root growth, foliar nitrogen and herbivory levels recovered in the next growing season following the cessation of elevated CO₂. Although the effects of elevated CO₂ cascade through plants to herbivores, they do not reach other trophic levels, and biodiversity remains unchanged. The legacy of 10 yr of elevated CO₂ on plant-herbivore interactions in this system appear to be minimal, indicating that the effects of elevated CO₂ may not accumulate over cycles of disturbance and recovery.

  5. Long-term measurements of refractive index structure constant in atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Jicha, Otakar; Pechac, Pavel; Zvanovec, Stanislav; Grabner, Martin; Kvicera, Vaclav

    2012-10-01

    Results of long-term measurements of the refractive index structure constant in the boundary layer are introduced. The measurements were made on a 150-meter-high lattice mast equipped by nineteen meteorological sensors and one pressure sensor at the bottom of the mast. The Kolmogorov statistical theory of turbulence was used to calculate the refractive index structure constant C2n, allowing us to present annual cumulative distribution functions (CDFs) and seasonal quantiles. The quantiles of measured height dependence of the refractive index structure constant are also shown and compared with existing models (Hufnagel/Andrews/Phillips, SLC Day and Gurvich). Parameters of a linear model were calculated to fit the measured median height profile of the refractive index structure constant with the uncertainty of measurements also being addressed.

  6. Long-term Impacts of Hurricane Wilma on Land Surface-Atmosphere Exchanges

    NASA Astrophysics Data System (ADS)

    Fuentes, J. D.; Dowell, K. K.; Engel, V. C.; Smith, T. J.

    2008-05-01

    In October 2005, Hurricane Wilma made landfall along the mangrove forests of western Everglades National Park, Florida, USA. Damage from the storm varied with distance from landfall and included widespread mortality and extensive defoliation. Large sediment deposition events were recorded in the interior marshes, with erosion taking place along the coastal margins. Wilma made landfall near a 30 m flux tower where eddy-covariance measurements of ecosystem-level carbon and energy fluxes started in 2003. Repairs to the structure were completed in 2006, enabling comparisons of surface fluxes before and after the storm. One year after the hurricane, both the average and daily integrated CO2 fluxes are consistently lower than the pre-storm values. The storm's impact on standing live biomass and the slow recovery of leaf area appear to have resulted in decreased photosynthetic uptake capacity. Nighttime respiratory CO2 fluxes above the canopy are unchanged from pre-storm values. During some periods, daily integrated fluxes show the forest as a net source of CO2 to the atmosphere. Soil CO2 fluxes are not measured directly, but daytime soil temperatures and vertical heat fluxes have shown consistently higher values after the storm. Nighttime soil temperatures values have been slightly lower. These stronger diurnal soil temperature fluctuations indicate enhanced radiative fluxes at the soil surface, possibly as a result of the reduced leaf area. The increases in daytime soil temperatures are presumably leading to higher below-ground respiration rates and, along with the reduced photosynthetic capacity, contributing to the lower net CO2 assimilation rates. This hypothesis is supported by nearby measurements of declining surface elevations of the organic soils which have been correlated with mangrove mortality in impacted areas. Both sensible and latent heat fluxes above the canopy are found to be reduced following the hurricane, and soil heat storage is higher. Together

  7. Modelling impacts of atmospheric deposition and temperature on long-term DOC trends.

    PubMed

    Sawicka, K; Rowe, E C; Evans, C D; Monteith, D T; E I Vanguelova; Wade, A J; J M Clark

    2017-02-01

    It is increasingly recognised that widespread and substantial increases in Dissolved organic carbon (DOC) concentrations in remote surface, and soil, waters in recent decades are linked to declining acid deposition. Effects of rising pH and declining ionic strength on DOC solubility have been proposed as potential dominant mechanisms. However, since DOC in these systems is derived mainly from recently-fixed carbon, and since organic matter decomposition rates are considered sensitive to temperature, uncertainty persists over the extent to which other drivers that could influence DOC production. Such potential drivers include fertilisation by nitrogen (N) and global warming. We therefore ran the dynamic soil chemistry model MADOC for a range of UK soils, for which time series data are available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on soil DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to raise the "acid recovery DOC baseline" significantly. In contrast, reductions in non-marine chloride deposition and effects of long term warming appeared to have been relatively unimportant. The suggestion that future DOC concentrations might exceed preindustrial levels as a consequence of nitrogen pollution has important implications for drinking water catchment management and the setting and pursuit of appropriate restoration targets, but findings still require validation from reliable centennial-scale proxy records, such as those being developed

  8. 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.

  9. 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.

  10. 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.

  11. Carbon sequestration and atmospheric CO2 removal: climate consequence and long-term commitment

    NASA Astrophysics Data System (ADS)

    Cao, L.; Caldeira, K.

    2010-12-01

    A variety of methods have been proposed to remove anthropogenic CO2 from the atmosphere and thus mitigate climate change, such as biospheric carbon sequestration, carbon sequestration through enhanced ocean and land weathering, and direct carbon capture from ambient air. Although these proposed methods differ substantially in their physical, chemical, and biological implementations, the ultimate outcome of all schemes is to remove anthropogenic CO2 from the atmosphere. However, the climate effect of atmospheric CO2 removal has not been studied. Here we use an Earth system model to investigate the response of the coupled climate-carbon system to an idealized removal of anthropogenic CO2 from the atmosphere. We use idealized scenarios in our analysis to facilitate exploration of the basic response of the coupled climate-carbon cycle system to proposed methods of removing anthropogenic CO2. In our extreme and idealized simulations, anthropogenic CO2 emissions are halted and all anthropogenic CO2 is removed from the atmosphere at year 2050 under the IPCC A2 CO2 emission scenario. In our simulations a one-time removal of all anthropogenic CO2 in the atmosphere reduces surface air temperature by 0.8°C within a few years, but 1°C surface warming above pre-industrial levels lasts for several centuries. In other words, a one-time removal of 100% excess CO2 from the atmosphere offsets less than 50% of the warming experienced at the time of removal. To maintain atmospheric CO2 and temperature at low levels, not only does anthropogenic CO2 in the atmosphere need to be removed, but anthropogenic CO2 stored in the ocean and land needs to be removed as well when it outgasses to the atmosphere. Our study indicts that the amount of CO2 that would need to be removed from the atmosphere, either by biological means or other means, could be much greater than the desired reduction in atmospheric CO2 concentrations, and may exceed the total burden of excess atmospheric CO2 at the time

  12. Monoterpene emissions in response to long-term night-time warming, elevated CO2 and extended summer drought in a temperate heath ecosystem.

    PubMed

    Tiiva, Päivi; Tang, Jing; Michelsen, Anders; Rinnan, Riikka

    2017-02-15

    Monoterpenes emitted from plants have an important role in atmospheric chemistry through changing atmospheric oxidative capacity, forming new particles and secondary organic aerosols. The emission rates and patterns can be affected by changing climate. In this study, emission responses to six years of climatic manipulations (elevated CO2, extended summer drought and night-time warming) were investigated in a temperate semi-natural heath ecosystem. Samples for monoterpene analysis were collected in seven campaigns during an entire growing season (April-November, 2011). The results showed that the temperate heath ecosystem was a considerable source of monoterpenes to the atmosphere, with the emission averaged over the 8month measurement period of 21.7±6.8μgm(-2)groundareah(-1) for the untreated heath. Altogether, 16 monoterpenes were detected, of which the most abundant were α-pinene, δ-3-carene and limonene. The emissions of these three compounds were positively correlated with light, chamber temperature and litter abundance, but negatively correlated with soil temperature. Elevated CO2 tended to decrease the average monoterpene emissions by 40% over the whole growing season, and significantly reduced emissions in August. Extended summer drought significantly decreased the emission right after the drought treatment period, but also in the late growing season. Night-time warming significantly increased the total emissions (mainly α-pinene) in April, and tended to mitigate the decrease caused by drought. The inhibition effects of elevated CO2 on emissions were diminished when the treatment was combined with drought or warming. The emission responses to different treatments were not explained by vegetation changes, and the monoterpene emission profile was only moderately related to plant species coverage. The emission responses to these long-term climate manipulations varied over the growing season (with strong correlation with litter abundance) and the observed

  13. Long-Term Simulated Atmospheric Nitrogen Deposition Alters Leaf and Fine Root Decomposition

    EPA Science Inventory

    Atmospheric nitrogen deposition has been suggested to increase forest carbon sequestration across much of the Northern Hemisphere; slower organic matter decomposition could contribute to this increase. At four sugar maple (Acer saccharum)-dominated northern hardwood forests, we p...

  14. 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

  15. Atmosphere/mantle coupling on Venus and long term planetary evolution.

    NASA Astrophysics Data System (ADS)

    Gillmann, C.; Tackley, P.

    2016-12-01

    We investigate the evolution of the venusian atmosphere and surface conditions and how they are linked with mantle dynamics through a coupled numerical model. Coupling occurs (i) due to mantle degassing, releasing volatiles into the atmosphere, and (ii) through surface temperature that provides a boundary condition for convection processes. We focus on volatile exchange mechanisms. During early evolution, hydrodynamic escape is dominant. We use a model developed to take into account the linked escape of Hydrogen and Oxygen. A significant portion of the early atmosphere can be removed this way. For later evolution, we focus on non-thermal escape. Post 4 Ga escape is low. The atmosphere is replenished by volcanic degassing. We use the advanced StagYY code for mantle dynamics to compute the evolution of the interior of Venus and corresponding volcanic output. Volatile fluxes are estimated for different mantle compositions and partitioning ratios. We use a gray radiative-convective model for the atmosphere of Venus, by tracking the evolution of greenhouse gasses in the atmosphere (water and CO2). Our mantle convection code then uses this temperature as a boundary condition. We are able to obtain Venus-like behavior for the solid planet, with resurfacing events constituting an efficient way of losing Venus' internal heat and leading to present-day conditions. CO2 pressure seems unlikely to vary much over the history of the planet, only slightly increasing due to degassing. A late build-up of the atmosphere with several resurfacing events seems unlikely. Water pressure is strongly sensitive to volcanic activity and varies rapidly leading to variations in surface temperatures of up to 200K. We observe a clear negative feedback of the atmosphere on volcanic activity, as higher surface temperatures lead to stagnant or episodic lid convection. Lower surface temperatures favor mobile lid convection.

  16. 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.

  17. Restoration of regeneration potential of long-term cultures of red fescue (Festuca rubra L.) by elevated sucrose levels.

    PubMed

    Zaghmout, O M; Torello, W A

    1992-04-01

    A tissue culture protocol for restoring embryogenic ability and increasing green plant regeneration from long-term callus (5-year old) and suspension cultures of "Dawson" red fescue (Festuca rubra var trichyoplylla Gaud) was developed. Pretreatment with elevated levels of sucrose over the standard level (60 mM) enhanced regeneration capacity and decreased the number of albino plants. The highest degree of embryogenesis and green shoot number occurred when calli were pre-treated on MS basal medium supplemented with 120 mM sucrose. Mannitol caused callus discoloration and death if added to pre-treatment media at 60, 90, 120, 150 or 180 mM. Cell suspension growth was greatest when 135 mM sucrose was added to the pre-treatment growth media. High concentrations of sucrose (135 and 180 mM) were necessary for plant regeneration from suspension aggregates pretreated with 135 or 180 mM sucrose and then plated on a growth regulator-free regeneration medium composed of half-strength MS salts and B5 vitamins.

  18. 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

  19. Studying atmospheric and ionospheric variabilities from long-term spectrometric and radio sounding measurements

    NASA Astrophysics Data System (ADS)

    Medvedeva, Irina; Ratovsky, Konstantin

    2015-06-01

    We investigated the variability in the neutral upper atmosphere and ionosphere parameters over East Siberia. The analysis is based on 2008-2014 data set of mesopause temperature (Tm) obtained from spectrometric measurements of the OH emission (834.0 nm, band (6-2)) at the Institute of Solar-Terrestrial Physics Geophysical Observatory (51.8°N, 103.1°E), and the data of F2 peak electron density (NmF2) from Irkutsk DPS-4 Digisonde (52.3°N, 104.3°E). The seasonal patterns of the NmF2 and Tm variability in different period ranges were analyzed and compared. The period range included day-to-day (periods T > 24 h) and tidal (8 h ≤ T ≤ 24 h) variations as well as variations in the internal gravity wave period range (T < 8 h). The comparison revealed both common features and distinctions in the seasonal patterns of the ionospheric and atmospheric variabilities. The main common feature is that the winter variability exceeds the summer one. In both atmospheric and ionospheric day-to-day variability seasonal variations, there are maxima in winter months and an additional maximum around the autumn equinox. The main distinction is that the equinox peaks observed in the seasonal variations of the diurnal atmospheric variability are not seen in the ionospheric seasonal pattern. The physical reasons of the obtained features are discussed. The revealed similarities in the seasonal behaviors may indicate that planetary waves propagating from the lower atmosphere layers have a significant impact on the mesopause temperature regime and ionospheric day-to-day variations.

  20. 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.

  1. 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.

  2. 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.

  3. Long term drift studies of Sandia H{sub 2} sensor in reducing atmospheres

    SciTech Connect

    JENKINS,MARK W.; HUGHES,ROBERT C.; PATEL,SANJAY V.

    2000-04-01

    A study of the drift in Pd/Ni alloy hydrogen sensitive resistor and transistor responses is presented. The sensors were monitored for a period of 6 months in a reducing atmosphere of 0.1% H{sub 2} in N{sub 2} with periodic calibration exposures. A comparison of a resistor film with an adhesion layer showed considerable improvement in diminishing the drift.

  4. Long-term change of the atmospheric energy cycles and weather disturbances

    NASA Astrophysics Data System (ADS)

    Kim, WonMoo; Choi, Yong-Sang

    2017-02-01

    Weather disturbances are the manifestation of mean atmospheric energy cascading into eddies, thus identifying atmospheric energy structure is of fundamental importance to understand the weather variability in a changing climate. The question is whether our observational data can lead to a consistent diagnosis on the energy conversion characteristics. Here we investigate the atmospheric energy cascades by a simple framework of Lorenz energy cycle, and analyze the energy distribution in mean and eddy fields as forms of potential and kinetic energy. It is found that even the widely utilized independent reanalysis datasets, NCEP-DOE AMIP-II Reanalysis (NCEP2) and ERA-Interim (ERA-INT), draw different conclusions on the change of weather variability measured by eddy-related kinetic energy. NCEP2 shows an increased mean-to-eddy energy conversion and enhanced eddy activity due to efficient baroclinic energy cascade, but ERA-INT shows relatively constant energy cascading structure between the 1980s and the 2000s. The source of discrepancy mainly originates from the uncertainties in hydrological variables in the mid-troposphere. Therefore, much efforts should be made to improve mid-tropospheric observations for more reliable diagnosis of the weather disturbances as a consequence of man-made greenhouse effect.

  5. Long-term change of the atmospheric energy cycles and weather disturbances

    NASA Astrophysics Data System (ADS)

    Kim, WonMoo; Choi, Yong-Sang

    2017-04-01

    Weather disturbances, including extreme weather phenomena, are the manifestation of mean atmospheric energy cascading into eddies. In this regard, the quantitative assessment of the atmospheric energy structure is a key to understand the weather variability in a changing climate. Whether our observational reanalysis data can lead to a consistent diagnosis on the energy conversion characteristics is thus an interesting question. Here we investigate the atmospheric energy cascades by a simple framework of Lorenz energy cycle, and analyze the energy distribution in mean and eddy fields as forms of potential and kinetic energy. Two widely utilized independent reanalysis datasets, NCEP-DOE AMIP-II Reanalysis (NCEP2) and ERA-Interim (ERA-INT), are selected for the analysis. Both datasets generally agree with the energy distribution and their conversion characteristics; however, they draw different conclusions on the change of weather variability measured by eddy-related kinetic energy. NCEP2 shows an increased mean-to-eddy energy conversion and enhanced eddy activity due to efficient baroclinic energy cascade, but ERA-INT shows relatively constant energy cascading structure between the 1980s and the 2000s. The source of discrepancy mainly originates from the uncertainties in hydrological variables in the mid-troposphere that links dynamics and physics. Therefore, a reliable diagnosis of the weather disturbances and their change as a consequence of man-made greenhouse effect require much improvement in the mid-tropospheric observations.

  6. 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.

  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. Test of developing long-term forecasts of world energy impact on the earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Klimenko, V. V.; Klimenko, A. V.; Tereshin, A. G.

    2015-03-01

    It has been established that the historical approach to world energy forecasting can yield useful results at time horizons with a depth of several decades. The genetic forecast supposes reaching a plateau of global energy consumption at the level of 30 billion tons of coal equivalent and an increase in the carbon dioxide concentration almost to 500 parts per million by the end of the century against the background of a continuing decrease in sulfur dioxide emission. From the historical point of view, the implementation of the most aggressive scenarios of human impact on the atmosphere and climate seems very unlikely.

  9. 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.

  10. 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.

  11. Embryonic response to long-term exposure of the marine crustacean Nephrops norvegicus to ocean acidification and elevated temperature

    PubMed Central

    Styf, Hannah K; Nilsson Sköld, Helen; Eriksson, Susanne P

    2013-01-01

    Due to anthropogenic CO2 emissions, our oceans have gradually become warmer and more acidic. To better understand the consequences of this, there is a need for long-term (months) and multistressor experiments. Earlier research demonstrates that the effects of global climate change are specific to species and life stages. We exposed berried Norway lobsters (Nephrops norvegicus), during 4 months to the combination of six ecologically relevant temperatures (5–18°C) and reduced pH (by 0.4 units). Embryonic responses were investigated by quantifying proxies for development rate and fitness including: % yolk consumption, mean heart rate, rate of oxygen consumption, and oxidative stress. We found no interactions between temperature and pH, and reduced pH only affected the level of oxidative stress significantly, with a higher level of oxidative stress in the controls. Increased temperature and % yolk consumed had positive effects on all parameters except on oxidative stress, which did not change in response to temperature. There was a difference in development rate between the ranges of 5–10°C (Q10: 5.4) and 10–18°C (Q10: 2.9), implicating a thermal break point at 10°C or below. No thermal limit to a further increased development rate was found. The insensitivity of N. norvegicus embryos to low pH might be explained by adaptation to a pH-reduced external habitat and/or internal hypercapnia during incubation. Our results thus indicate that this species would benefit from global warming and be able to withstand the predicted decrease in ocean pH in the next century during their earliest life stages. However, future studies need to combine low pH and elevated temperature treatments with hypoxia as hypoxic events are frequently and increasingly occurring in the habitat of benthic species. PMID:24455136

  12. Long-term prognosis of chronic kidney disease in non-ST elevation acute coronary syndrome treated with invasive strategy.

    PubMed

    Roldán Torres, Ildefonso; Salvador Mercader, Inmaculada; Cabadés Rumbeu, Claudia; Díez Gil, José Luis; Ferrando Cervelló, José; Monteagudo Viana, Marta; Fernández Galera, Rubén; Mora Llabata, Vicente

    Patients with chronic kidney disease (CKD) have an increased risk of adverse cardiovascular outcomes after non-ST elevation acute coronary syndrome (NSTEACS). However, the information available on this specific population, is scarce. We evaluate the impact of CKD on long-term prognosis in patients with NSTEACS managed with invasive strategy. We conduct a prospective registry of patients with NSTEACS and coronary angiography. CKD was defined as a glomerular filtration rate < 60ml/min/1,73m(2). The composite primary end-point was cardiac death and non fatal cardiovascular readmission. We estimated the cumulative probability and hazard rate (HR) of combined primary end-point at 3-years according to the presence or absence of CKD. We included 248 p with mean age of 66.9 years, 25% women. CKD was present at baseline in 67 patients (27%). Patients with CKD were older (74.9 vs. 63.9 years; P<.0001) with more prevalence of hypertension (89.6 vs. 66.3%; P<.0001), diabetes (53.7 vs. 35.9%; P=.011), history of heart failure (13.4 vs. 3.9%; P=.006) and anemia (47.8 vs. 16%; P<.0001). No differences in the extent of coronary artery disease. CKD was associated with higher cumulative probability (49.3 vs. 28.2%; log-rank P=.001) and HR of the primary combined end-point (HR: 1.94; CI95%: 1.12-3.27; P=.012). CKD was an independent predictor of adverse cardiovascular outcomes at 3-years (HR: 1.66; CI95%: 1.05-2.61; P=.03). In NSTEACS patients treated with invasive strategie CKD is associated independently with an increased risk of adverse cardiovascular outcomes at 3years. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  13. Embryonic response to long-term exposure of the marine crustacean Nephrops norvegicus to ocean acidification and elevated temperature.

    PubMed

    Styf, Hannah K; Nilsson Sköld, Helen; Eriksson, Susanne P

    2013-12-01

    Due to anthropogenic CO2 emissions, our oceans have gradually become warmer and more acidic. To better understand the consequences of this, there is a need for long-term (months) and multistressor experiments. Earlier research demonstrates that the effects of global climate change are specific to species and life stages. We exposed berried Norway lobsters (Nephrops norvegicus), during 4 months to the combination of six ecologically relevant temperatures (5-18°C) and reduced pH (by 0.4 units). Embryonic responses were investigated by quantifying proxies for development rate and fitness including: % yolk consumption, mean heart rate, rate of oxygen consumption, and oxidative stress. We found no interactions between temperature and pH, and reduced pH only affected the level of oxidative stress significantly, with a higher level of oxidative stress in the controls. Increased temperature and % yolk consumed had positive effects on all parameters except on oxidative stress, which did not change in response to temperature. There was a difference in development rate between the ranges of 5-10°C (Q 10: 5.4) and 10-18°C (Q 10: 2.9), implicating a thermal break point at 10°C or below. No thermal limit to a further increased development rate was found. The insensitivity of N. norvegicus embryos to low pH might be explained by adaptation to a pH-reduced external habitat and/or internal hypercapnia during incubation. Our results thus indicate that this species would benefit from global warming and be able to withstand the predicted decrease in ocean pH in the next century during their earliest life stages. However, future studies need to combine low pH and elevated temperature treatments with hypoxia as hypoxic events are frequently and increasingly occurring in the habitat of benthic species.

  14. 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.

  15. Long Term Atmospheric Deposition of Trace Elements to the Sargasso Sea

    NASA Astrophysics Data System (ADS)

    Church, T. M.; Veron, A. J.; Alleman, L.

    2001-12-01

    Trace element deposition to surface ocean waters relates to both the emission sources from surrounding continents and micro-nutrient requirements of marine organisms. This is particularly true in mid-ocean gyres such as the Saragasso Sea surrounded by large industrial regions such as in North America and Europe. Atmospheric deposition for trace elements has been sampled at Bermuda since 1982 under three separate programs. The micro-nutrients include natural crustal elements (Fe, Mn) from dust, and anthropogenic elements (Cd, Cu, Zn) from combustion sources. The Bermuda deposition record shows large scale variations of these elements over the past two decades, both on seasonal and inter-annual scales. The changes in dust elements appear related to variations in climatic conditions, such as the NAO index which could effect source transport, or aridity in the Saharan source regions which should effect source strength. Those changes in the other industrial elements, related to variations in combustion practices such as ore smelting or biomass burning. None of these changes the atmospheric delivery of micro-nutrient elements may effect surface ocean productivity if these sources are replete for the North Atlantic relative to other potentially limiting nutrients such as P. The element Pb from similar combustion sources has had very large scale reductions in the Bermuda record due to the phasing out of leaded gasoline first in North America followed by Europe. The regional sources and transient fate of lead in the surface Sargasso can be traced using its stable isotope signature. Included is the downward ventilation of the transient tracer, plus the role of surface advection in its mass balance.

  16. Temperature climatology of the middle atmosphere from long-term lidar measurements at mid- and low-latitudes

    NASA Technical Reports Server (NTRS)

    McDermid, I. Stuart; Leblanc, Thierry; Keckhut, Philippe; Hauchecorne, Alain; She, C. Y.; Krueger, David A.

    1998-01-01

    The temperature structure of the middle atmosphere has been studied for several decades using a variety of techniques. However, temperature profiles derived from lidar measurements can provide improved vertical resolution and accuracy. Lidars can also provide long-term data series relatively absent of instrumental drift, and integration of the measurements over several hours removes most of the gravity wave-like short-scale disturbances. This paper describes a seasonal climatology of the middle atmosphere temperature derived from lidar measurements obtained at several mid- and low-latitude locations. Results from the following lidars, which have all obtained a long-term measurement record, were used in this study: the two Rayleigh lidars of the Service d'Aeronomie du CNRS, France, located at the Observatoire de Haute Provence (OHP, 44.0 deg N) and at the Centre d'Essais des Landes (CEL, 44.0 deg N), the two Rayleigh/Raman lidars of the Jet Propulsion Laboratory, USA, located at Table Mountain, California (TMF, 34.4 deg N) and at Mauna Loa, Hawaii (MLO, 19.5 deg N), and the Colorado State University, USA, sodium lidar located at Fort Collins, Colorado (CSU, 40.6 deg N). The overall data set extends from 1978 to 1997 with different periods of measurements depending on the instrument. Three of the instruments are located at primary or complementary stations (OHP, TMF, MLO) within the Network for Detection of Stratospheric Change (NDSC). Several aspects of the temperature climatology obtained by lidar in the middle atmosphere are presented, including the climatological temperature average through the year; the annual and semi-annual components, and the differences compared to the CIRA-86 climatological model.

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

    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 NOx from the polar lower mesosphere and upper stratosphere during the Southern Hemisphere winter period resulted in huge enhancements (>100%) in middle stratospheric NOx (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, NOy (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 NOy resulted in long-lasting ozone decreases (from catalytic NOy destruction of ozone) and ozone increases (from NOy interference in the chlorine and bromine catalytic ozone destruction cycles). These ozone changes resulted in simulated SH polar stratospheric temperature decreases (1-2K) and increases (1-3K).

  18. 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)..

  19. 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)..

  20. Increasing Juniperus virginiana L. pollen in the Tulsa atmosphere: long-term trends, variability, and influence of meteorological conditions.

    PubMed

    Flonard, Michaela; Lo, Esther; Levetin, Estelle

    2017-09-15

    In the Tulsa area, the Cupressaceae is largely represented by eastern red cedar (Juniperus virginiana L.). The encroachment of this species into the grasslands of Oklahoma has been well documented, and it is believed this trend will continue. The pollen is known to be allergenic and is a major component of the Tulsa atmosphere in February and March. This study examined airborne Cupressaceae pollen data from 1987 to 2016 to determine long-term trends, pollen seasonal variability, and influence of meteorological variables on airborne pollen concentrations. Pollen was collected through means of a Burkard sampler and analyzed with microscopy. Daily pollen concentrations and yearly pollen metrics showed a high degree of variability. In addition, there were significant increases over time in the seasonal pollen index and in peak concentrations. These increases parallel the increasing population of J. virginiana in the region. Pollen data were split into pre- and post-peak categories for statistical analyses, which revealed significant differences in correlations of the two datasets when analyzed with meteorological conditions. While temperature and dew point, among others were significant in both datasets, other factors, like relative humidity, were significant only in one dataset. Analyses using wind direction showed that southerly and southwestern winds contributed to increased pollen concentrations. This study confirms that J. virginiana pollen has become an increasing risk for individuals sensitive to this pollen and emphasizes the need for long-term aerobiological monitoring in other areas.

  1. Development of an H-TDMA for long-term unattended measurement of the hygroscopic properties of atmospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Nilsson, E.; Swietlicki, E.; Sjogren, S.; Löndahl, J.; Nyman, M.; Svenningsson, B.

    2009-04-01

    A new hygroscopic tandem differential mobility analyzer (H-TDMA) has been constructed at Lund University within the frameworks of the EU FP6 Infrastructure Project EUSAAR (http://www.eusaar.org/). The aim of this coordinated H-TDMA development is to design and evaluate a new generation of H-TDMAs that are capable of conducting long term measurements of the hygroscopic growth and state of mixing of sub-micrometer atmospheric aerosol particles at the EUSAAR aerosol super-sites across Europe. The H-TDMA constructed for this project has been validated with respect to hygroscopic growth factor, stability of relative humidity (RH), temperature stability and its ability to operate unattended for longer periods of time. When measuring growth factors of ammonium sulphate, the new H-TDMA system was found to measure within a growth factor deviation of ±0.05 compared to previously recorded data by Tang et al. (1994). The long term RH of the system has been found stable at 90.0% with a standard deviation of ±0.23% and an average temperature variability of the second DMA less than ±0.1 K. Daily automated ammonium sulphate measurements have validated the ambient measurements. The instrument is operated at the EMEP/EUSAAR background station Vavihill in the southern part of Sweden.

  2. Development of an H-TDMA for long-term unattended measurement of the hygroscopic properties of atmospheric aerosol particles

    NASA Astrophysics Data System (ADS)

    Nilsson, E.; Swietlicki, E.; Sjogren, S.; Löndahl, J.; Nyman, M.; Svenningsson, B.

    2009-06-01

    A new hygroscopic tandem differential mobility analyzer (H-TDMA) has been constructed at Lund University within the frameworks of the EU FP6 Infrastructure Project EUSAAR (http://www.eusaar.org/). The aim of this coordinated H-TDMA development is to design and evaluate a new generation of H-TDMAs that are capable of conducting long term measurements of the hygroscopic growth and state of mixing of sub-micrometer atmospheric aerosol particles at the EUSAAR aerosol super-sites across Europe. The H-TDMA constructed for this project has been validated with respect to hygroscopic growth factor, stability of relative humidity (RH), temperature stability and its ability to operate unattended for longer periods of time. When measuring growth factors of ammonium sulphate, the new H-TDMA system was found to measure within a growth factor deviation of ±0.05 compared to previously recorded data by Tang et al. (1994). The long term RH of the system has been found stable at 90.0% with a standard deviation of ±0.23% and an average temperature variability of the second DMA less than ±0.1 K. Daily automated ammonium sulphate measurements have validated the ambient measurements. The instrument is operated at the EMEP/EUSAAR background station Vavihill in the southern part of Sweden.

  3. 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.

  4. 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.

  5. Long-term dynamics of atmospheric circulation over Siberia and its relationship with air temperature

    NASA Astrophysics Data System (ADS)

    Podnebesnykh, N. V.; Ippolitov, I. I.

    2012-12-01

    The main objective of this study is the investigation of cyclone characteristics variability in the region bounded by the coordinates 50°-70° N, 60°-110° W which includes Western Siberia and the part of Eastern Siberia for the time interval 1976-2006, as well as the establishment of statistical relationships between the temperature conditions and the atmospheric circulation. For the dynamics of the climatic characteristics of cyclones and anticyclones over Siberia surface synoptic maps were used, and to study the trends of air temperature daily data from 169 ground-based meteorological stations and posts located in the study area were analyzed. During the period of the modern warming the territory of Siberia was characterized by rapidly temperature increase: average annual value was 0.36°C/10 years, and average monthly value was 0.83°C/10 years. The positive trend of temperature increasing is shown for all months except November. The total number of cyclones over the territory of under study for the period of 1976-2006 has decreased at a rate of 1.4 cyclone/10 years. For further analysis all cyclones were divided into three groups, according to their directions: north, west and south. It was found the number of south and west cyclones decreased, whole the number of cyclone from north directions increased. Such multidirectional dynamics of cyclones from different directions can be associated with the processes of strengthening and weakening of the Polar and Arctic fronts in the Atlantic sector of the Northern Hemisphere. Among characteristics of vortex activity the pressure in the centers of cyclones and anticyclones has the greatest influence on the air temperature and the total number of cyclones has the smallest. Multiple regression models have shown that in different months of a year the circulation can describe from 54% to 82% of temperature variability.

  6. Long-term atmospheric visibility trends in megacities of China, India and the United States.

    PubMed

    Hu, Yue; Yao, Ling; Cheng, Zhen; Wang, Yungang

    2017-11-01

    Millions of premature deaths worldwide every year mostly in China and India are contributed by the poor air quality. The atmospheric visibility is a proven indicator of the ambient air quality. In this study, nine megacities were selected, including Beijing, Shanghai and Guangzhou from China, Chicago, Los Angeles (LA) and New York City (NYC) from the United States, and Mumbai, Chennai and Jaipur from India. The data of visibility, aerosol optical depth (AOD), and meteorological factors from 1973 to 2015 were collected. The temporal variations of annual and monthly percentages of bad days (visibility < 5km) and good days (visibility > 15km) were evaluated. Visibility of Chicago, LA and NYC gradually improved during the past 43 years and has reached a very good level (good day percentages: 75-88%; bad day percentages: 0 - 4%). Conversely, visibility in Mumbai, Chennai and Jaipur continued deteriorating and suffered an extremely poor visibility situation in recent years (good day percentages: 0; bad day percentages: 6-100%). Likewise, visibility in Beijing, Shanghai and Guangzhou has experienced the worsening period during the industrial development from 1970s and turned better after the 1990s. A strong seasonal pattern of bad day percentages of each year were observed in most cities, especially in the winter, which is caused by the fossil fuel combustion for heating, relatively high relative humidity, and other unfavorable meteorological conditions. The low visibility events occurred more frequently in days with low wind speeds and specific wind directions, further explaining the seasonal patterns of visibility. With population growth from the period of 2000-2010 to the period of 2011-2015, AOD and bad day percentages both increased in Mumbai, Chennai, Jaipur and Beijing while others were relatively stable. This study demonstrated that the macro-control of pollution emissions could effectively reduce air deterioration. The relationships among visibility variation

  7. 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

  8. Seasonal phosphatase activity in three characteristic soils of the English uplands polluted by long-term atmospheric nitrogen deposition.

    PubMed

    Turner, Benjamin L; Baxter, Robert; Whitton, Brian A

    2002-01-01

    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 (micromol para-nitrophenol g(-1) soil dry wt. h(-1)) ranged between 83.9 and 307 in a blanket peat (total carbon 318 mg g(-1). pH 3.9), 45.2-86.4 in an acid organic grassland soil (total carbon 354 mg g(-1), pH 3.7) and 10.4-21.1 in a calcareous grassland soil (total carbon 140 mg g(-1) pH 7.3). These are amongst the highest reported soil phosphomonoesterase activities and confirm the strong biological phosphorus limitation in this environment.

  9. 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.

  10. Effects of long-term nitrogen fertilization on the uptake kinetics of atmospheric methane in temperate forest soils.

    PubMed

    Gulledge, Jay; Hrywna, Yarek; Cavanaugh, Colleen; Steudler, Paul A

    2004-09-01

    To determine whether repeated, long-term NH(4) (+) fertilization alters the enzymatic function of the atmospheric CH(4) oxidizer community in soil, we examined CH(4) uptake kinetics in temperate pine and hardwood forest soils amended with 150 kg N ha(-1) y(-1) as NH(4)NO(3) for more than a decade. The highest rates of atmospheric CH(4) consumption occurred in the upper 5 cm mineral soil of the control plots. In contrast to the results of several previous studies, surface organic soils in the control plots also exhibited high consumption rates. Fertilization decreased in situ CH(4) consumption in the pine and hardwood sites relative to the control plots by 86% and 49%, respectively. Fertilization increased net N mineralization and relative nitrification rates and decreased CH(4) uptake most dramatically in the organic horizon, which contributed substantially to the overall decrease in field flux rates. In all cases, CH(4) oxidation followed Michaelis-Menten kinetics, with apparent K(m) (K(m(app))) values typical of high-affinity soil CH(4) oxidizers. Both K(m(app)) and V(max(app)) were significantly lower in fertilized soils than in unfertilized soils. The physiology of the methane consumer community in the fertilized soils was distinct from short-term responses to NH(4) (+) addition. Whereas the immediate response to NH(4) (+) was an increase in K(m(app)), resulting from apparent enzymatic substrate competition, the long-term response to fertilization was a community-level shift to a lower K(m(app)), a possible adaptation to diminish the competitiveness of NH(4) (+) for enzyme active sites.

  11. Climate impacts on rising atmospheric CO2 from long-term time-series of CO2 and O2

    NASA Astrophysics Data System (ADS)

    Keeling, R. F.; Rafelski, L. E.; Piper, S. C.

    2009-04-01

    The long-term time series of atmospheric CO2 and O2 concentrations from the Scripps Institution of oceanography now span 51 and 19 years, respectively. These time series will be presented together with the ice-core CO2 records and discussed in terms of the processes controlling the atmospheric CO2 rise, particularly the sensitivity of the natural sinks for CO2 in the land and ocean to climate changes. The CO2 record provides constraints on the sensitivity of the land sinks to climate. The CO2 rise can be expressed as an anomaly relative to the trend expected from fossil-fuel burning, land use emissions, and uptake by the land biosphere and oceans, with the latter two processes depicted by simple reservoir models (land sink driven by CO2 fertilization). Despite uncertainties, the anomaly computed this way shows an evident link with global land temperature, with both the anomaly and temperature trend showing breaks in slope around 1940 and 1980. Climate effects on the land biosphere may thus explain two otherwise puzzling features in the CO2 record: the plateau in growth in the 1940s and the persistent high growth after 1980. The implied effect of warming on CO2 suggested by this decadal variability is too small to be a significant climate feedback, however. Additional constraints on the climate sensitivity of ocean sinks can be obtained by combining the CO2 and O2 records. The ocean CO2 sink that would have been obtained in the absence of climate change is quite well constrained based on ocean observations of chlorofluorocarbons. This sink can be compared to the sink computed from the global O2 budget, assuming the oceans have not been a long-term source or sink for O2. The comparison reveals a significant discrepancy, which suggests that climate changes are impacting some combination of the long-term O2 and CO2 fluxes. The climate effect is qualitatively consistent with ocean models, which predict that warming will reduce oceanic uptake of CO2 and induce oceanic

  12. Long-term Variation in Temperature and Dynamics in Venus Upper Atmosphere from ground-based Infrared Heterodyne Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sornig, Manuela; Sandor, Brad; Stangier, Tobias; Krause, Pia; Wischnewski, Caro; Kostiuk, Ted; Livengood, Tim

    Dynamics of the Venusian atmospheric transition zone between the sub-solar to anti-solar (SS-AS) flow dominated region above 120km and the superrotation dominated region below 90 km is not yet fully understood. Temperatures in the same region are not very well constrained and we lack a comprehensive understanding of this atmospheric region. Therefore direct measurements of these parameters on various time scales and on different locations on the planet are essential to validate global circulation models and for a comprehensive understanding of the atmosphere. Such observations can be provided by the infrared heterodyne spectrometers THIS (University of Cologne) and HIPWAC (NASA GSFC). Operating around 10μm both instruments fully resolve CO2 non-LTE emission lines for Doppler-wind and temperature retrievals at an pressure level of 1μbar (~110 km). In addition to this “one-altitude” information the broader CO2 absorption lines can be used to gain information about the temperature profile at attitudes in the range 60-90 km. Long term variability in Doppler-wind velocities and temperature at ~110km from campaigns between 1990 to 2013 will be presented. A report about local wave activities will be included. In addition recently retrieved temperature profiles from 60 to 90 km will be shown.

  13. The middle Pleistocene transition: characteristics, mechanisms, and implications for long-term changes in atmospheric pCO 2

    NASA Astrophysics Data System (ADS)

    Clark, Peter U.; Archer, David; Pollard, David; Blum, Joel D.; Rial, Jose A.; Brovkin, Victor; Mix, Alan C.; Pisias, Nicklas G.; Roy, Martin

    2006-12-01

    The emergence of low-frequency, high-amplitude, quasi-periodic (˜100-kyr) glacial variability during the middle Pleistocene in the absence of any significant change in orbital forcing indicates a fundamental change internal to the climate system. This middle Pleistocene transition (MPT) began 1250 ka and was complete by 700 ka. Its onset was accompanied by decreases in sea surface temperatures (SSTs) in the North Atlantic and tropical-ocean upwelling regions and by an increase in African and Asian aridity and monsoonal intensity. During the MPT, long-term average ice volume gradually increased by ˜50 m sea-level equivalent, whereas low-frequency ice-volume variability experienced a 100-kyr lull centered on 1000 ka followed by its reappearance ˜900 ka, although as a broad band of power rather than a narrow, persistent 100-kyr cycle. Additional changes at 900 ka indicate this to be an important time during the MPT, beginning with an 80-kyr event of extreme SST cooling followed by the partial recovery and subsequent stabilization of long-term North Atlantic and tropical ocean SSTs, increasing Southern Ocean SST variability primarily associated with warmer interglacials, the loss of permanent subpolar sea-ice cover, and the emergence of low-frequency variability in Pacific SSTs and global deep-ocean circulation. Since 900 ka, ice sheets have been the only component of the climate system to exhibit consistent low-frequency variability. With the exception of a near-universal organization of low-frequency power associated with marine isotope stages 11 and 12, all other components show an inconsistent distribution of power in frequency-time space, suggesting a highly nonlinear system response to orbital and ice-sheet forcing. Most hypotheses for the origin of the MPT invoke a response to a long-term cooling, possibly induced by decreasing atmospheric pCO 2. None of these hypotheses, however, accounts for the geological constraint that the earliest Northern Hemisphere

  14. Annual cycle and long-term trend of the methane total column in the atmosphere over the St. Petersburg region

    NASA Astrophysics Data System (ADS)

    Makarova, M. V.; Kirner, O.; Timofeev, Yu. M.; Poberovskii, A. V.; Imkhasin, Kh. Kh.; Osipov, S. I.; Makarov, B. K.

    2015-07-01

    The annual cycle and long-term trend of the methane total column in the atmosphere over the Petergof station (St. Petersburg State University) are analyzed on the basis of data obtained from Fourier-transform infrared spectrometry and EMAC-model calculations. The amplitude of the annual cycle of the total column of CH4 amounts to 2.1 and 1.5% according to experimental and model data, respectively. For the atmospheric column-averaged mole fraction of CH4, the amplitude of its annual cycle is smaller than that for its total column and amounts to 1.1 and 0.6% according to experimental and model data, respectively. The results of local continuous measurements of surface CH4 concentrations showed that, in 2013, the atmospheric column-averaged mole fractions of CH4 and the amplitudes of diurnal variations in its local concentration were characterized by the same dynamics of seasonal variations. An analysis made on the basis of simulation results showed that atmospheric conditions (under which Fourier-transform IR measurements were performed) could increase the amplitude of the annual cycle of the total column of CH4 2.5 times when compared to the true one. The results of Fourier-transform IR measurements and EMAC-model calculations showed that, during 2009-2012, the atmospheric concentration of CH4 increased at a rate of ~0.2% per year. If measurement data obtained in 2013 are added, this rate decreases to ~0.13% per year.

  15. A long-term perspective of the hydroclimatological impacts of atmospheric rivers over the central United States

    NASA Astrophysics Data System (ADS)

    Nayak, Munir Ahmad; Villarini, Gabriele

    2017-02-01

    The focus of this study is on the climatology of atmospheric rivers (ARs) over the central United States using six atmospheric reanalysis products. This climatology is used to understand the long-term impacts of ARs on annual precipitation, precipitation extremes, and flooding over the central United States. The relationship between the frequency of ARs and three prominent large-scale atmospheric modes [Pacific-North American (PNA) teleconnection, Artic Oscillation (AO), and North Atlantic Oscillation (NAO)] is investigated, and the results are used to statistically model the frequency of ARs at the seasonal scale. AR characteristics (e.g., frequency, duration) are generally robust across the different reanalysis products. ARs exhibit a marked seasonality, with the largest activity in winter (more than 10 ARs per season on average), and the lowest in summer (less than two ARs per season on average). Overall, the duration of most ARs is less than 3 days, but exceptionally persistent ARs (more than 6 days) are also observed. The year-to-year variations in the total annual precipitation over the central United States are largely explained by the variations in AR-related precipitation. Moreover, 40% of the top 1% daily precipitation extremes are associated with ARs, and more than 70% of the annual instantaneous peak discharges and peaks-overthreshold floods are associated with these storms, in particular during winter and spring. The seasonal frequency of ARs can be described in terms of large-scale atmospheric modes, with PNA playing a major role in particular in winter and spring.

  16. Atmospheric annular modes in simulations over the past millennium: No long-term response to external forcing

    NASA Astrophysics Data System (ADS)

    Gómez-Navarro, J. J.; Zorita, E.

    2013-06-01

    This study analyzes whether the imprint of external forcings can be detected in the long-term evolution of the main atmospheric circulation patterns in climate simulations over the last millennium. The external forcing is not found to significantly add variability in any frequency band compared to control simulations where the external drivers are kept constant. Additionally, a method designed to detect a common signal in the time evolution of these circulation patterns among all simulations is proposed, and employed to demonstrate that the null hypothesis of an evolution dominated by internal variability cannot be rejected regardless of the time smoothing applied to the series. Given that the fingerprint of external forcings on atmospheric circulation has been successfully detected in simulations of the 20th century climate and in future climate change projections, we argue that either the effect of past natural forcing is too small, state-of-the-art climate models underestimate their climate sensitivity, or the anthropogenic forcing qualitatively differs from the natural forcing in its effect on main circulation patterns.

  17. 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)].

  18. Long term measurements of trace gases at the Weybourne Atmospheric Observatory, seasonal variation and long range transport

    NASA Astrophysics Data System (ADS)

    Fleming, Z. L.; Monks, P. S.; Bandy, B. J.; Penkett, S. A.; Koumoutsaris, S.; Bey, I.

    2009-04-01

    Fifteen years of data from the UK NCAS (National Centre for Atmospheric Science) funded atmospheric observatory in Weybourne in North Norfolk, UK, on the North Sea have been analysed to study long term changes of a series of trace gases. The site's coastal location is ideal for dividing the air masses into clean North Sea/Arctic, polluted North European and urban UK sectors. A more detailed analysis of the exact pathway of the air arriving at the site has been studied using back trajectories, wind sectors and output from the UK Met office's NAME (Atmospheric dispersion) model. The dataset is not continuous for all species during the whole 15 year period but several intensive field campaigns with comprehensive VOC measurements have proved to be an essential addition. Ratios of various hydrocarbons and trace gases at the site show the origin and age of the air masses arriving at the site and division of the datasets by air mass direction and season illustrate the changing air composition of Northern Europe. The GEOS-Chem model was used to model ozone levels at the site and compare well to observations, especially for the clean air masses from the Northerly and Easterly North Sea and Arctic sectors. Other UK monitoring sites (Harwell and Great Dun Fell) ozone trends were compared to those at Weybourne, revealing a certain regional difference but a similar trend peak ozone values declining and background levels gradually increasing. The marine influence at Weybourne also show periods that represent non UK pollution emissions and Arctic air that contains relatively high background ozone levels. Ozone levels at Weybourne have changed considerably over this period due to changes in their precursors.

  19. 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...

  20. 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...

  1. 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.

  2. 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.

  3. The Budget of the Atmosphere-Soil Exchange: A Long-term Fluxes Analysis (BASE:ALFA) project.

    NASA Astrophysics Data System (ADS)

    Caporaso, L.; di Giuseppe, F.; Bonafè, G.

    2010-09-01

    A long term measurements of parameters characterizing the energy and water cycle in the Po Valley (Italy) has been carried out between summers 2009 and 2010 to create a data pool of micro-meteorological/soil data to test and validate Surface Vegetation Atmosphere Transfer Scheme (SVATS) and Regional Numerical weather prediction R-NWP with respect to the representation of near-surface processes. The BASE:ALFA project organized in the middle of the Po valley was thought as a prototype experience which tried to fulfill the need highlighted in recent SRNWP program for a network of surface stations which should soon appear in Europe as a spontaneous cooperation of national weather services. We report on our experimental campaigns and on some modeling outcomes. In particular, we will present one targeted application of the collected dataset, which we found of special interest for the area. That is how the wrong PBL mixing height modeling can impact air quality assessment. Most air quality models for pollutant concentrations estimations, in fact, uses R-NWP predicted and or analyzed PBL mixing height to estimate air quality indices, as for example PM10 concentrations.

  4. Elevated catalase and heme oxygenase-1 may contribute to improved postischaemic cardiac function in long-term type 1 diabetes.

    PubMed

    Shen, Wei-Li; Zhong, Mei-Fang; Ding, Wen-Long; Wang, Jian; Zheng, Lin; Zhu, Ping; Wang, Bing-Shun; Higashino, Hideaki; Chen, Hong

    2008-07-01

    1. Although increased oxidative stress has been shown repeatedly to be implicated in diabetes, the cardiovascular anti-oxidant state and heart response to ischaemia in long-term Type 1 diabetes remain largely unknown. The present study was designed to observe heart tolerance to ischaemia-reperfusion and endogenous anti-oxidants in the cardiovascular system in long-term hyperglycaemic rats. 2. Hearts from Sprague-Dawley rats surviving up to 6 months with streptozocin-induced severe hyperglycaemia (blood glucose > 20 mmol/L) were isolated and subjected to global ischaemia and reperfusion. Cardiac function, electrocardiogram and anti-oxidants in the myocardium and aorta were examined. In addition, the morphology of the myocardial mitochondria and the in vitro function of aortic vessels were assessed. 3. Hearts from diabetic rats demonstrated lower baseline heart function but had higher postischaemic coronary flow and left ventricular developed pressure compared with their respective controls (P < 0.05). In addition, hearts from diabetic animals had fewer arrhythmias (P < 0.01) and lower left ventricular end-diastolic pressure during reperfusion (P < 0.05). Higher catalase and heme oxygenase-1 content was found in the aorta and myocardium from diabetic rats (P < 0.01). In aortas from diabetic animals, acetylcholine-induced vasodilatation was enhanced and was approximately 15% after inhibition of nitric oxide synthase, compared with 0% in controls. The 15% relaxation was abrogated by heme oxygenase blockade. Mitochondria from the myocardium of diabetic rats showed significant increases in both size and number (P < 0.05). 4. Hearts of long-term Type 1 diabetic rats demonstrated improved recovery of postischaemic cardiac function and reduced reperfusion arrhythmia. Hyperglycaemia may enhance cardiovascular anti-oxidant capacity and mitochondrial neogenesis, which renders the heart resistant to ischaemia and oxidative injury.

  5. Long-term intermittent hypoxia elevates cobalt levels in the brain and injures white matter in adult mice.

    PubMed

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

    2013-10-01

    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. Participants were randomly allocated to a control or experimental group (single independent variable). University animal house. Adult male C57BL/6J mice. To model OSA, mice were exposed to long-term intermittent hypoxia (LTIH) for 10 hours/day for 8 weeks or sham intermittent hypoxia (SIH). 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. 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.

  6. Impact of door-to-balloon time on long-term mortality in high- and low-risk patients with ST-elevation myocardial infarction.

    PubMed

    Yudi, Matias B; Ramchand, Jay; Farouque, Omar; Andrianopoulos, Nick; Chan, William; Duffy, Stephen J; Lefkovits, Jeffrey; Brennan, Angela; Spencer, Ryan; Fernando, Dharsh; Hiew, Chin; Freeman, Melanie; Reid, Christopher M; Ajani, Andrew E; Clark, David J

    2016-12-01

    Door-to-balloon time (DTBT) less than 90min remains the benchmark of timely reperfusion in ST-elevation myocardial infarction (STEMI). The relative long-term benefit of timely reperfusion in STEMI patients with differing risk profiles is less certain. Thus, we aimed to assess the impact of DTBT on long-term mortality in high- and low-risk STEMI patients. We analysed baseline clinical and procedural characteristics of 2539 consecutive STEMI patients who underwent primary percutaneous coronary intervention (PCI) from the Melbourne Interventional Group registry from 2004 to 2012. Patients were classified high risk (HR-STEMI) if they presented with cardiogenic shock, out-of-hospital cardiac arrest (OHCA) or Killip class ≥2; or low-risk (LR-STEMI) if there were no high-risk features. We then stratified high- and low-risk patients by DTBT (≤90min vs. >90min) and assessed long-term mortality. Of the 2539 patients, 395 (16%) met the high-risk criteria. A DTBT ≤90min was achieved in 43% of HR-STEMI patients and in 55% of LR-STEMI patients. Patients in the HR-STEMI compared to LR-STEMI cohort had higher in-hospital (31% vs. 1%, p<0.01) and long-term mortality (37% vs. 7%, p<0.01). A DTBT ≤90min was associated with significant improvements in short- and long-term mortality in both groups. A DTBT ≤90min was an independent multivariate predictor of long-term survival in LR-STEMI (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.3-0.9, p=0.02) but not in HR-STEMI (HR 0.7, 95% CI 0.5-1.1, p=0.11). A DTBT ≤90min was associated with improved short- and long-term outcomes in high- and low-risk STEMI patients. However, it was only an independent predictor of long-term survival in LR-STEMI patients. Copyright © 2016. Published by Elsevier Ireland Ltd.

  7. Observational research study around tropical Western Pacific: PALAU (Pacific Area Long-term Atmospheric observation for Understanding climate change) project

    NASA Astrophysics Data System (ADS)

    Shirooka, Ryuichi

    2017-04-01

    The warm water pool region in the tropical Western Pacific is a key area for global climate systems, as strong atmospheric convective activity in this area is the driving engine of the atmosphere. However, there are many processes between meso-scale convective activities and the global-scale climate, and these are not fully understood yet. To understand the mechanism of clouds-precipitation processes and air-sea interactions over the warm pool in the tropics, there are in need of further investigation on the Western Pacific monsoon and the tropical-extratropical interactions. Toward these objectives, we have continued a long-term observational project named PALAU (Pacific Area Long-term Atmospheric observation for Understanding climate change) around the tropical Western Pacific near the Republic of Palau. The main target of this project is to describe multi-scale interactions of cloud systems to intra-seasonal oscillations affected by monsoon activities. To elucidate the structure of tropical cyclones, which occur over a monsoon trough near Palau, is also a major interest. Since November 2000, we have been continuously operating a surface weather observation site in Palau. We also have conducted several intensive field campaigns targeted for various phenomena. PALAU2013, one of the intensive campaign, was carried out to focus on the formation mechanism of tropical cyclones and their relation to intra-seasonal oscillations and monsoon activity over the tropical Western Pacific. During the campaign, R/V Mirai was placed near Palau and conducted atmospheric and oceanic observations using Doppler radar, radiosonde, CTD and so on. Daily profiling Argo-floats were deployed for analyzing air-sea interactions. To capture the monsoon activity with wide area, we constructed intensified sounding network from Philippines, Palau, and Yap to Guam. Three X-band radars were utilized to obtain the internal structure of cloud systems. Dual-polarization parameters also can be

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

    Treesearch

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

    2015-01-01

    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...

  9. 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.

  10. Short-term and long-term root respiratory acclimation to elevated temperatures associated with root thermotolerance for two Agrostis grass species.

    PubMed

    Rachmilevitch, Shimon; Lambers, Hans; Huang, Bingru

    2008-01-01

    This study was designed to investigate whether thermotolerant roots exhibit respiratory acclimation to elevated temperatures. Root respiratory acclimation traits in response to increasing temperatures were compared between two Agrostis species contrasting in heat tolerance: thermal A. scabra and heat-sensitive A. stolonifera. Roots of both species were exposed to 17, 27, or 37 degrees C. Root RGR declined with increasing temperatures from 17 degrees C to 37 degrees C in both species; however, root growth of A. scabra maintained a significantly higher RGR than A. stolonifera at 27 degrees C or 37 degrees C. A. scabra exhibited a significantly higher respiration acclimation potential to elevated temperatures, both in the short term (60 min) and in the long term (7-28 d) as compared with A. stolonifera, when temperatures increased from 17 degrees C to 27 degrees C or from 27 degrees C to 37 degrees C. Thermal A. scabra also maintained a significantly lower maintenance cost than A. stolonifera as temperatures increased to 27 degrees C or 37 degrees C. The results suggested that root thermotolerance of thermal A. scabra was associated with both short-term and long-term respiratory acclimation to changes in temperatures. The superior ability of adjusting the rate of root respiration to compensate for increases in carbon demand during short- or long-term temperature increases in the heat-tolerant A. scabra may result in the reduction in carbon expenditure or costs for maintenance, leading to extended root survivability in high temperature soils.

  11. 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.

  12. 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...

  13. 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...

  14. 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.

  15. Long-term prognostic value of a comprehensive assessment of cardiac magnetic resonance indexes after an ST-segment elevation myocardial infarction.

    PubMed

    Merlos, Pilar; López-Lereu, Maria P; Monmeneu, Jose V; Sanchis, Juan; Núñez, Julio; Bonanad, Clara; Valero, Ernesto; Miñana, Gema; Chaustre, Fabián; Gómez, Cristina; Oltra, Ricardo; Palacios, Lorena; Bosch, Maria J; Navarro, Vicente; Llácer, Angel; Chorro, Francisco J; Bodí, Vicente

    2013-08-01

    A variety of cardiac magnetic resonance indexes predict mid-term prognosis in ST-segment elevation myocardial infarction patients. The extent of transmural necrosis permits simple and accurate prediction of systolic recovery. However, its long-term prognostic value beyond a comprehensive clinical and cardiac magnetic resonance evaluation is unknown. We hypothesized that a simple semiquantitative assessment of the extent of transmural necrosis is the best resonance index to predict long-term outcome soon after a first ST-segment elevation myocardial infarction. One week after a first ST-segment elevation myocardial infarction we carried out a comprehensive quantification of several resonance parameters in 206 consecutive patients. A semiquantitative assessment (altered number of segments in the 17-segment model) of edema, baseline and post-dobutamine wall motion abnormalities, first pass perfusion, microvascular obstruction, and the extent of transmural necrosis was also performed. During follow-up (median 51 months), 29 patients suffered a major adverse cardiac event (8 cardiac deaths, 11 nonfatal myocardial infarctions, and 10 readmissions for heart failure). Major cardiac events were associated with more severely altered quantitative and semiquantitative resonance indexes. After a comprehensive multivariate adjustment, the extent of transmural necrosis was the only resonance index independently related to the major cardiac event rate (hazard ratio=1.34 [1.19-1.51] per each additional segment displaying>50% transmural necrosis, P<.001). A simple and non-time consuming semiquantitative analysis of the extent of transmural necrosis is the most powerful cardiac magnetic resonance index to predict long-term outcome soon after a first ST-segment elevation myocardial infarction. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  16. Effects of elevated atmospheric carbon dioxide on soil nitrogen cycling

    NASA Astrophysics Data System (ADS)

    Hofmockel, Kirsten S.

    Human activities including fossil fuel combustion, deforestation, and land conversion to agriculture have caused the concentration of atmospheric CO2 to increase since the Industrial Revolution. One approach to atmospheric CO2 reduction is sequestration in forest ecosystems. Presently little is known about the overall impact of elevated atmospheric CO2 on net ecosystem carbon storage, particularly in terms of nutrient limitations. In this dissertation I tested the hypothesis that elevated atmospheric CO2 will stimulate soil N availability, supporting long-term CO 2 sequestration in southeastern forests, examined asymbiotic N2 fixation, amino acid assimilation and ecosystem scale N cycling to understand changes in soil N cycling induced by elevated atmospheric CO 2. All research was conducted at the Duke Forest free Air CO2 Enrichment (FACE) experiment, where atmospheric CO2 concentrations have been maintained at 200 ul l-1 above ambient levels in the 30-m diameter treatment plots since 1996. This body of research indicates that elevated atmospheric CO2 does not stimulate soil N cycling at the decadal time scale. Field measurements of exogenous N inputs via asymbiotic N2 fixing bacteria reveal no CO2 stimulation. Soil moisture was the most important factor controlling field rates of N2 fixation. Changes in endogenous N cycling were evaluated using stable isotope tracer field experiments. Short-term experiments showed that more amino acid N was assimilated by both fine roots and microbes under ambient compared to elevated CO2. This significant treatment effect indicates that soil C limitation was a stronger driver of amino acid cycling than N limitation. Intact amino acid assimilation was comparable to NH4 assimilation and may make a small, but important contribution to plant N uptake in warm-temperate forest ecosystems. Inorganic N cycling was not affected by elevated atmospheric CO2. After two growing seasons, a 15N field tracer experiment showed no effects of

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

    DOE PAGES

    Kim, Keonhee; Labbé, Nicole; Warren, Jeffrey M.; ...

    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

  18. 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.

  19. Long-term recovery of a Louisiana brackish marsh plant community from oil-spill impact: vegetation response and mitigating effects of marsh surface elevation.

    PubMed

    Hester, M W; Mendelssohn, I A

    2000-04-01

    Oil spills can have significant, short-term, negative impacts on coastal marshes, but the long-term effects and eventual recovery are not well documented, particularly in brackish marshes. The goals of this investigation were to: (1) document the long-term recovery of a Louisiana brackish marsh plant community impacted by a 1985 oil spill; (2) separate the effect of the oil spill on marsh deterioration from ambient rates of marsh deterioration; and (3) assess the relative importance of residual oil in the sediment and decreased marsh surface elevation in the failure of certain areas to recover. A total of 68 permanent plots previously established in 1985 were re-surveyed for plant and soil recovery in the fall of 1989. Although substantial (and near total) vegetative recovery was evident by significant increases in live and total vegetative cover, many of the plots that were initially heavily impacted by oil still displayed elevated levels of total saturated hydrocarbons in the soil. August 1990 measurements of plant photosynthetic response and edaphic variables revealed no significant differences between control plots and plots heavily impacted by oil that displayed vegetative regrowth. Rates of wetland land loss in the oiled marsh during an 8-year period that bracketed the time of the spill were within the historical range measured for this site and similar to the land loss rates of adjacent reference marshes. Results from a manipulative field transplant experiment indicated that the long-term failure of certain small areas to revegetate was primarily due to a decrease of marsh surface elevation (increased flooding stress), not a residual oil effect.

  20. 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.

  1. Long-term acclimation to elevated pCO2 alters carbon metabolism and reduces growth in the Antarctic diatom Nitzschia lecointei

    PubMed Central

    Torstensson, Anders; Hedblom, Mikael; Mattsdotter Björk, My; Chierici, Melissa; Wulff, Angela

    2015-01-01

    Increasing atmospheric CO2 levels are driving changes in the seawater carbonate system, resulting in higher pCO2 and reduced pH (ocean acidification). Many studies on marine organisms have focused on short-term physiological responses to increased pCO2, and few on slow-growing polar organisms with a relative low adaptation potential. In order to recognize the consequences of climate change in biological systems, acclimation and adaptation to new environments are crucial to address. In this study, physiological responses to long-term acclimation (194 days, approx. 60 asexual generations) of three pCO2 levels (280, 390 and 960 µatm) were investigated in the psychrophilic sea ice diatom Nitzschia lecointei. After 147 days, a small reduction in growth was detected at 960 µatm pCO2. Previous short-term experiments have failed to detect altered growth in N. lecointei at high pCO2, which illustrates the importance of experimental duration in studies of climate change. In addition, carbon metabolism was significantly affected by the long-term treatments, resulting in higher cellular release of dissolved organic carbon (DOC). In turn, the release of labile organic carbon stimulated bacterial productivity in this system. We conclude that long-term acclimation to ocean acidification is important for N. lecointei and that carbon overconsumption and DOC exudation may increase in a high-CO2 world. PMID:26354939

  2. Gender and Age Differences in Short- and Long-Term Outcomes Following Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction

    PubMed Central

    Chua, Su-Kiat; Shyu, Kou-Gi; Hung, Huei-Fong; Cheng, Jun-Jack; Lo, Huey-Ming; Liu, Shih-Chi; Chen, Lung-Ching; Chiu, Chiung-Zuan; Chang, Che-Ming; Lin, Shen-Chang; Liou, Jer-Young; Lee, Shih-Huang

    2014-01-01

    Background Studies have reported that women with ST elevation myocardial infarction (STEMI) have worse short- and long-term outcomes than men. It has not yet been confirmed whether these differences reflect differences in age between men and women. Methods We retrospectively enrolled 1035 consecutive STEMI patients treated with primary percutaneous coronary intervention (PCI). Baseline clinical characteristics, coronary anatomy, and outcome were compared between young (< 65 years old) and older patients (≥ 65 years old) of both sexes. Results Younger women presented with a lower incidence of typical angina (83% vs. 93%, p = 0.03), single-vessel disease (21% vs. 35%, p = 0.03), and total occlusion of infarct-related artery (65% vs. 83%, p = 0.001) than younger men, with no gender difference noted in the older group. Younger women in the study had a higher incidence of reinfarction, heart failure requiring admission, or mortality (23% vs. 6%, p < 0.001) during follow-up, compared with younger men, with no gender difference in the older group. Using the Kaplan-Meier analysis, younger women had lower rates of event-free survival (p < 0.001 by log-rank test) than younger men, with no gender difference in the older group. In multivariate analysis, age could predict long-term outcome in men (Hazard ratio 4.43, 95% confidence interval: 2.89-6.78, p < 0.001) but not in women. Conclusions In STEMI patients receiving primary PCI, sex-related long-term outcome differences were age-dependent, with younger women likely to have a worse long-term outcome when compared with younger men. PMID:27122800

  3. Long-term mortality in patients with ST-segment elevation myocardial infarction is associated with anti-citrullinated protein antibodies.

    PubMed

    Hermans, Maaike P J; van der Velden, Daniel; Montero Cabezas, José M; Putter, Hein; Huizinga, Tom W J; Kuiper, Johan; Toes, Rene E M; Schalij, Martin J; Wouter Jukema, J; van der Woude, Diane

    2017-08-01

    Cardiovascular (CV) mortality is higher in patients with rheumatoid arthritis (RA), in particular when anti-citrullinated protein antibodies (ACPA) are present. Recently, ACPA have also been described in a cohort of patients without RA, but with coronary artery disease (CAD). It is however unknown if ACPA can consistently be found in patients with CAD, and if ACPA are associated with mortality in these patients. The purpose of this study was to assess the relationship between ACPA and long-term outcomes including mortality in patients with ST-elevation myocardial infarction (STEMI) without RA. All patients with STEMI from the MISSION! Intervention Study were analyzed. Patients with RA were excluded. The association between ACPA (anti-CCP3) at baseline and 10year mortality and re-infarction was investigated. In total, 29 (11%) of 275 included patients were ACPA-positive, substantiating the previous description of ACPA in CAD patients. Increased cumulative cardiac mortality was observed in ACPA-positive patients in comparison with ACPA-negative patients. Moreover, after correction for other associated factors, ACPA-positivity was associated with long-term mortality (HR 3.1 [CI 1.4-7.1] p-value=0.01) and long-term combined endpoint of re-infarction and death (HR 2.4 [1.2-4.6] p-value=0.01). In STEMI patients without RA, the presence of ACPA is independently associated with long-term mortality and the combined endpoint of re-infarction and death. ACPA in patients with and without RA might act as an independent pro-atherogenic factor. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. 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

  5. Long-term pasture under elevated CO2 and N management: CO2 flux patterns upon return to cultivation

    USDA-ARS?s Scientific Manuscript database

    Soil CO2 efflux patterns associated with converting pastures back to row crop production remain understudied in the Southeastern US. A 10-year study of bahiagrass (Paspalum notatum Flüggé) response to elevated CO2 was conducted using open top field chambers on a Blanton loamy sand (loamy siliceous, ...

  6. 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

  7. Photosynthetic responses of yellow poplar and white oak to long term atmospheric CO sub 2 enrichment in the field. [Liriondendron tulipifera L; Quercus alba L

    SciTech Connect

    Gunderson, C.A.; Norby, R.J. )

    1991-05-01

    A critical consideration in evaluating forest response to rising atmospheric CO{sub 2} is whether the enhancement of net photosynthesis (P{sub N}) by elevated CO{sub 2} can be sustained over the long term. There are reports of declining enhancement of P{sub N} with duration of exposure to elevated CO{sub 2}, associated with decreases in photosynthetic capacity and carboxylation efficiency. We investigated whether this photosynthetic acclimation occurs in two tree species under field conditions. Seedlings of yellow-poplar (Liriodendron tulipifera L.) and white oak (Quercus alba L.) were planted in the ground within six open-top field chambers in May 1989 and have been exposed continuously to CO{sub 2} enrichment during the last two growing seasons. The three CO{sub 2} treatment levels were: ambient, ambient +150, and ambient +300 {mu}L/L. Throughout the second season, gas exchange of upper, light-saturated leaves was surveyed periodically, and leaves of different ages and canopy positions were measured occasionally. Net photosynthesis remained higher at higher CO{sub 2} levels (28-32% higher in +150 and 49-67% higher in +300 seedlings) in both species throughout the season, regardless of increasing leaf age and duration of exposure to CO{sub 2} enrichment. Stomatal conductance remained unchanged or decreased slightly with increasing CO{sub 2}, but instantaneous water use efficiency (P{sub N}/transpiration) increased significantly with CO{sub 2}. Analysis of P{sub N} versus internal CO{sub 2} concentration indicated no significant treatment differences in carboxylation efficiency, CO{sub 2}-saturated P{sub N}, or CO{sub 2} compensation point. There was no evidence of a downward acclimation of photosynthesis to CO{sub 2} enrichment in this system.

  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. 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  12. 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

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

    PubMed

    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.

  14. 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.

  15. 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.

  16. [Effects of nitrogen fertilization on wheat leaf photosynthesis under elevated atmospheric CO2 concentration].

    PubMed

    Yu, Xian-feng; Zhang, Xu-cheng; Guo, Tian-wen; Yu, Jia

    2010-09-01

    In this paper, the effects of nitrogen (N) fertilization on the wheat leaf photosynthesis under long-term elevated atmospheric CO2 concentration (760 micromol x mol(-1)) was studied, based on the measurements of photosynthetic gas exchange parameters and light intensity-photosynthetic rate response curves at jointing stage. Under the long-term elevated atmospheric CO2 concentration, applying sufficient N could increase the wheat leaf photosynthetic rate (Pn), transpiration rate (Tr), and instantaneous water use efficiency (WUEi). Comparing with those under ambient atmospheric CO2 concentration, the Po and WUEi under the elevated atmospheric CO2 concentration increased, while the stomatal conductance (Gs) and intercellular CO2 concentration (Ci) decreased. With the increase of light flux intensity, the Pn and WUEi under the elevated atmospheric CO2 concentration were higher those under ambient atmospheric CO2 concentration, Gs was in adverse, while Ci and Tr had less change. At high fertilization rate of N, the Gs was linearly positively correlated with Pn, Tr, and WUEi, and the Gs and Ci had no correlation with each other under the elevated atmospheric CO2 concentration but negatively correlated under ambient atmospheric CO2 concentration. At low fertilization rate of N, the Gs had no correlations with Pn and WUEi but linearly positively correlated with Ci and Tr. It was suggested that under the elevated atmospheric CO2 concentration, the wheat leaf Pn at low N fertilization rate was limited by non-stomatal factor.

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

    USDA-ARS?s Scientific Manuscript database

    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 (...

  18. 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.

  19. Influence of coronary vessel dominance on short- and long-term outcome in patients after ST-segment elevation myocardial infarction.

    PubMed

    Veltman, Caroline E; van der Hoeven, Bas L; Hoogslag, Georgette E; Boden, Helèn; Kharbanda, Rohit K; de Graaf, Michiel A; Delgado, Victoria; van Zwet, Erik W; Schalij, Martin J; Bax, Jeroen J; Scholte, Arthur J H A

    2015-05-01

    Prognostic importance of coronary vessel dominance in patients with ST-elevation myocardial infarction (STEMI) remains uncertain. The aim of this study was to assess influence of coronary vessel dominance on the short- and long-term outcome after STEMI. Coronary angiographic images of consecutive patients presenting with first STEMI were retrospectively reviewed to assess coronary vessel dominance. Patients were followed after STEMI during a median period of 48 (IQR38-61) months for the occurrence of all-cause mortality and the composite of reinfarction and cardiac death. The population comprised 1131 patients of which 971 (86%) patients had a right dominant, 102 (9%) a left dominant, and 58 (5%) a balanced system. After 5 years of follow-up, the cumulative incidence of all-cause mortality was significantly higher in patients with a left dominant system, compared with a right dominant and balanced system (log-rank P = 0.013). Moreover, a left dominant system was an independent predictor for 30-day mortality (OR 2.51, 95% CI 1.11-5.67, P = 0.027) and the composite of reinfarction and cardiac death within 30-days after STEMI (OR 2.25, 95% CI 1.09-4.61, P = 0.028). In patients surviving first 30-days post-STEMI, coronary vessel dominance had no influence on long-term outcome. A left dominant coronary artery system is associated with a significantly increased risk of 30-day mortality and early reinfarction after STEMI. After surviving the first 30-days post-STEMI, coronary vessel dominance had no influence on long-term outcome. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  20. Long-Term Outcomes of Hospitalized Patients with a Non-Acute Coronary Syndrome Diagnosis and an Elevated Cardiac Troponin Level

    PubMed Central

    McFalls, Edward O.; Larsen, Greg; Johnson, Gary; Apple, Fred S.; Goldman, Steven; Arai, Andrew; Nallamathu, Brahmajee; Jesse, Bob; Holmstrom, Scott T.; Sinnott, Patricia L.

    2013-01-01

    Background Cardiac troponin levels help risk-stratify patients presenting with an acute coronary syndrome (ACS). Although they may be elevated in patients presenting with Non-ACS conditions, specific diagnoses and long-term outcomes within that cohort are unclear. Methods and Results Using the Veterans Affairs (VA) centralized databases, we identified all hospitalized patients in 2006 who had a troponin assay obtained during their initial reference hospitalization. Based on ICD-9 diagnostic codes, primary diagnoses were categorized as either ACS or Non-ACS conditions. Of a total of 21,668 patients with an elevated troponin level who were discharged from the hospital, 12,400 (57.2%) had a Non-ACS condition. Among that cohort, the most common diagnostic category involved the cardiovascular system and congestive heart failure (N=1661) and chronic coronary artery disease (N=1648) accounted for the major classifications. At one-year following hospital discharge, mortality in patients with a Non-ACS condition was 22.8% and was higher than the ACS cohort (Odds Ratio=1.39; 95%CI: 1.30–1.49). Despite the high prevalence of cardiovascular diseases in patients with a Non-ACS diagnosis, utilization of cardiac imaging within 90 days of hospitalization was low compared with ACS patients (Odds Ratio=0.25; 95%CI: 0.23–0.27). Conclusions Hospitalized patients with an elevated troponin level most often have a primary diagnosis that is not an acute coronary syndrome. Their long-term survival is poor and justifies novel diagnostic or therapeutic strategy-based studies to target the highest risk subsets prior to hospital discharge. PMID:21601821

  1. Long-term Prognosis of Patients With Non-ST-segment Elevation Acute Myocardial Infarction and Coronary Arteries Without Significant Stenosis.

    PubMed

    Redondo-Diéguez, Alfredo; Gonzalez-Ferreiro, Rocío; Abu-Assi, Emad; Raposeiras-Roubin, Sergio; Aidhodjayeva, Ozoda; López-López, Andrea; Castiñeira-Busto, María; Peña-Gil, Carlos; García-Acuña, Jose María; González-Juanatey, José Ramón

    2015-09-01

    There is debate regarding the prognostic significance of the absence of significant coronary lesions in patients with non-ST-segment elevation acute myocardial infarction. We investigated long-term prognosis in a contemporary cohort of these patients. Retrospective observational study of 5203 patients with acute coronary syndrome. Propensity score matching was used to create 2 groups of 367 patients with non-ST-segment elevation acute myocardial infarction matched by the absence or presence of significant coronary lesions. In the matched cohort, we determined the impact of the absence of significant coronary lesions on mortality or readmission for acute coronary syndrome for 4.8 (2.6) years after discharge. Mortality or readmission for acute coronary syndrome was lower among patients without significant lesions (26.4% vs 32.7%; P = .09). Mortality in both groups was 19.1%. In contrast, patients without significant lesions had a lower incidence of readmission for acute coronary syndrome (2.0/100 vs 3.9/100 person-years; P = .003). The incidence of mortality or readmission for acute coronary syndrome was similar in patients without significant lesions and those with significant 1-vessel disease (26.4% vs 27.5%; P = .19), but lower than that in patients with 2-vessel disease (37.8%; P = .007) and 3-vessel disease or left main coronary artery disease (41.1%; P = .002). Patients with non-ST-segment elevation acute myocardial infarction and coronary arteries without significant lesions have similar long-term mortality but lower readmission rates for acute coronary syndrome than patients with significant lesions. Mortality or readmission for acute coronary syndrome is similar in patients without significant lesions and patients with 1-vessel disease, but lower than in patients with disease in 2 or more vessels. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  2. Discerning the role of atmospheric deposition in long-term solute trends in large rivers of the United States

    NASA Astrophysics Data System (ADS)

    Stets, E.

    2014-12-01

    Trends in alkalinity and other solutes are evident in large rivers of the United States (U.S.) due to a variety of factors. Nutrient inputs, agricultural lime, decreasing acidic inputs, and changing flow conditions all contribute to trends in major solutes. In small, minimally disturbed headwater watersheds with limited acid neutralizing capacity, solute trends resulting from changes in acidic deposition are well documented. Larger rivers tend to have greater acid neutralizing capacity and are subject to a greater number of anthropogenic pressures. Therefore, the effects of acid deposition on larger rivers is expected to be minimal. In this study, trends in alkalinity and other solutes were determined in large rivers spanning a range of climate and land use characteristics in the U.S. Multi-decadal trend analyses were performed (1945-2010) using a robust flow-weighting scheme. Alkalinity increased in most rivers although the factors leading to the increases were highly diverse. In several rivers in the Northeastern U.S., the timing and magnitude of alkalinity trends indicated that changes in atmospheric deposition played a role in solute trends. Despite the recent increases in alkalinity, modern alkalinity concentrations in U.S. rivers are remarkably similar to those observed in the early 20th century (1906-1910). On the other hand, sulfate and calcium concentrations remain elevated with respect to data from the early 20th century suggesting that acidification processes are ongoing, although improvements occurred in many areas in recent decades.

  3. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. 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

  5. Long-term elevation of temperature affects organic N turnover and associated N2O emissions in a permanent grassland soil

    NASA Astrophysics Data System (ADS)

    Jansen-Willems, Anne B.; Lanigan, Gary J.; Clough, Timothy J.; Andresen, Louise C.; Müller, Christoph

    2016-11-01

    Over the last century an increase in mean soil surface temperature has been observed, and it is predicted to increase further in the future. In order to evaluate the legacy effects of increased temperature on both nitrogen (N) transformation rates in the soil and nitrous oxide (N2O) emissions, an incubation experiment and modelling approaches were combined. Based on previous observations that gross N transformations in soils are affected by long-term elevated-temperature treatments we hypothesized that any associated effects on gaseous N emissions (e.g. N2O) can be confirmed by a change in the relative emission rates from various pathways. Soils were taken from a long-term in situ warming experiment on temperate permanent grassland. In this experiment the soil temperature was elevated by 0 (control), 1, 2 or 3 °C (four replicates per treatment) using IR (infrared) lamps over a period of 6 years. The soil was subsequently incubated under common conditions (20 °C and 50 % humidity) and labelled as NO315NH4 Gly, 15NO3NH4 Gly or NO3NH4 15N-Gly. Soil extractions and N2O emissions were analysed using a 15N tracing model and source-partitioning model. Both total inorganic N (NO3- + NH4+) and NO3- contents were higher in soil subjected to the +2 and +3 °C temperature elevations (pre- and post-incubation). Analyses of N transformations using a 15N tracing model showed that, following incubation, gross organic (but not inorganic) N transformation rates decreased in response to the prior soil warming treatment. This was also reflected in reduced N2O emissions associated with organic N oxidation and denitrification. Furthermore, a newly developed source-partitioning model showed the importance of oxidation of organic N as a source of N2O. In conclusion, long-term soil warming can cause a legacy effect which diminishes organic N turnover and the release of N2O from organic N and denitrification.

  6. 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. Copyright

  7. 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.

  8. Are The Large-Scale Biosphere-Atmosphere Experiment In Amazonia (LBA) Representative Of Long-Term Climatology? A Study Using Climate Weather Stations In Brazil.

    NASA Astrophysics Data System (ADS)

    Rosolem, R.; Shuttleworth, W. J.; Goncalves, L. G.

    2007-12-01

    The Large-Scale Biosphere-Atmosphere Experiment in Amazonia has already contributed understanding of the flux exchange between the Amazonian rainforest and atmosphere and other significant components of the ecohydrometeorological system, and it will continue to do so. However, when considering LBA-derived information on whether the Amazon is a source or sink of carbon, or whether land use changes in the Amazon are affecting the local and perhaps global climate, it is important to characterize the period during which the LBA project has been carried out in terms of its climatological context. In other words, to address the question "How does the climate during the LBA data collection period compare with the long-term climatology in Amazon." Such information is not only useful for future project planning but is crucial information for modeling purposes: the calibration or validation of models using LBA data may be influenced by the climate conditions prevalent when these data were collected. This investigates the extent to which the actual period of data collection at LBA sites is representative of the long-term climatology for the sites. The research uses long-term weather station data taken from the databases of Brazilian National Water Agency (Agencia Nacional de Aguas - ANA) and National Oceanic and Atmospheric Administration - National Climatic Data Center division (NOAA-NCDC) for stations located near the Sao Gabriel da Cachoeira, Manaus, Santarem, Caxiuana, Jaru, Sinop, and Bananal LBA sites, and compares these weather station data during the LBA data collection period with the entire dataset available for each weather station. Analysis of the precipitation records demonstrates that the precipitation climate during the LBA study period was not significant different from the long- term climatology at all the LBA sites but that at a few sites the temperature climate during LBA was statistically different.

  9. 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

  10. Long-term exposure to elevated carbon dioxide does not alter activity levels of a coral reef fish in response to predator chemical cues.

    PubMed

    Sundin, Josefin; Amcoff, Mirjam; Mateos-González, Fernando; Raby, Graham D; Jutfelt, Fredrik; Clark, Timothy D

    2017-01-01

    Levels of dissolved carbon dioxide (CO2) projected to occur in the world's oceans in the near future have been reported to increase swimming activity and impair predator recognition in coral reef fishes. These behavioral alterations would be expected to have dramatic effects on survival and community dynamics in marine ecosystems in the future. To investigate the universality and replicability of these observations, we used juvenile spiny chromis damselfish (Acanthochromis polyacanthus) to examine the effects of long-term CO2 exposure on routine activity and the behavioral response to the chemical cues of a predator (Cephalopholis urodeta). Commencing at ~3-20 days post-hatch, juvenile damselfish were exposed to present-day CO2 levels (~420 μatm) or to levels forecasted for the year 2100 (~1000 μatm) for 3 months of their development. Thereafter, we assessed routine activity before and after injections of seawater (sham injection, control) or seawater-containing predator chemical cues. There was no effect of CO2 treatment on routine activity levels before or after the injections. All fish decreased their swimming activity following the predator cue injection but not following the sham injection, regardless of CO2 treatment. Our results corroborate findings from a growing number of studies reporting limited or no behavioral responses of fishes to elevated CO2. Alarmingly, it has been reported that levels of dissolved carbon dioxide (CO2) forecasted for the year 2100 cause coral reef fishes to be attracted to the chemical cues of predators. However, most studies have exposed the fish to CO2 for very short periods before behavioral testing. Using long-term acclimation to elevated CO2 and automated tracking software, we found that fish exposed to elevated CO2 showed the same behavioral patterns as control fish exposed to present-day CO2 levels. Specifically, activity levels were the same between groups, and fish acclimated to elevated CO2 decreased their swimming

  11. Atmospheric Oxygen Inhibits Growth and Differentiation of Marrow-Derived Mouse Mesenchymal Stem Cells via a p53 Dependent Mechanism: Implications for Long-Term Culture Expansion

    PubMed Central

    Boregowda, Siddaraju; Krishnappa, Veena; Chambers, Jeremy; LoGrasso, Phillip V.; Lai, Wen-Tzu; Ortiz, Luis A.; Phinney, Donald G.

    2013-01-01

    Large scale expansion of human mesenchymal stem cells (MSCs) is routinely performed for clinical therapy. In contrast, developing protocols for large scale expansion of primary mouse MSCs has been more difficult due to unique aspects of rodent biology. Currently, established methods to isolate mouse MSCs select for rapidly dividing subpopulations that emerge from bone marrow cultures following long-term (months) expansion in atmospheric oxygen. Herein, we demonstrate that exposure to atmospheric oxygen rapidly induced p53, TOP2A and BAX expression and mitochondrial ROS generation in primary mouse MSCs resulting in oxidative stress, reduced cell viability and inhibition of cell proliferation. Alternatively, procurement and culture in 5% oxygen supported more prolific expansion of the CD45−ve/CD44+ve cell fraction in marrow, produced increased MSC yields following immuno-depletion, and supported sustained MSC growth resulting in a 2300-fold increase in cumulative cell yield by 4th passage. MSCs cultured in 5% oxygen also exhibited enhanced tri-lineage differentiation. The oxygen-induced stress response was dependent upon p53 since siRNA mediated knockdown of p53 in wild type cells or exposure of p53−/− MSCs to atmospheric oxygen failed to induce ROS generation, reduce viability, or arrest cell growth. These data indicate that long-term culture expansion of mouse MSCs in atmospheric oxygen selects for clones with absent or impaired p53 function, which allows cells to escape oxygen-induced growth inhibition. In contrast, expansion in 5% oxygen generates large numbers of primary mouse MSCs that retain sensitivity to atmospheric oxygen, and therefore a functional p53 protein, even after long-term expansion in vitro. PMID:22367737

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

    PubMed

    Sellin, Arne; Niglas, Aigar; Õunapuu-Pikas, Eele; Kupper, Priit

    2014-03-24

    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. 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. 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 will impose greater risk of desiccation

  14. MAVEN Observations of Present-Day Atmospheric Loss to Space: Implications for Long-Term Volatile Evolution

    NASA Astrophysics Data System (ADS)

    Jakosky, B. M.

    2016-12-01

    MAVEN will complete its first Mars year of science mapping in October 2016. Results show loss of gas to space by multiple processes, including solar-wind pick-up, sputtering, photochemical loss, and thermal escape, along with their response to changing solar/solar-wind boundary conditions and to discrete solar events. With these results, we are able to examine the long-term loss to space, including the effects of different solar conditions early in history and the ability to use stable-isotope ratios to derive integrated loss. Preliminary results suggest that loss to space was a dominant, if not the dominant, mechanism for changing the climate through time. We will present a framework for analyzing and interpreting the results, along with preliminary results on the extrapolation to long timescales. Changes being implemented for our extended mission that have the ability to significantly augment our results will be described.

  15. Mars atmospheric loss to space: Observations of present-day loss and implications for long-term volatile evolution

    NASA Astrophysics Data System (ADS)

    Jakosky, Bruce; Brain, David; Luhmann, Janet; Grebowsky, Joe

    2017-04-01

    MAVEN completed its first Mars year of science mapping in October 2016. Results show loss of gas to space by multiple processes, including solar-wind pick-up, sputtering, photochemical loss, and thermal escape, along with their responses to changing solar and solar-wind boundary conditions and to discrete solar events. By understanding the current loss rates and the processes controlling them, we are able to examine the long-term loss to space, including the effects of different solar conditions early in history; in addition, we are able to use stable-isotope ratios to derive the integrated loss to space through time. Preliminary results suggest that loss to space was a dominant, if not the dominant, mechanism that drove the changing climate through time. We will present a framework for analyzing and interpreting the results, along with preliminary results on the extrapolation to long timescales.

  16. 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.

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

    Treesearch

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

    2015-01-01

    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 elevatedCO2 concentrations on tree foliar chemistry are well...

  18. Response of a southeastern U.S. bahiagrass pasture to elevated atmospheric CO2 and N fertilization

    USDA-ARS?s Scientific Manuscript database

    In the Southeastern US both managed and unmanaged pasture systems remain understudied agro-ecosystems in terms of the effects of elevated atmospheric CO2 concentration. Therefore, we initiated a long-term study of bahiagrass (Paspalum notatum Flüggé) response to elevated CO2 using open top field cha...

  19. Patency of paclitaxel-eluting versus bare metal stents long term after implantation in acute ST-segment elevation myocardial infarction.

    PubMed

    Vink, Maarten A; Van Nooijen, Ferdinand C; Laarman, Gerrit J; Suttorp, Maarten J; Tijssen, Jan G; Slagboom, Ton; Patterson, Mark S; Van Der Schaaf, Rene J; Kiemeneij, Ferdinand; Amoroso, Giovanni; Dirksen, Maurits T

    2011-11-01

    Drug-eluting stents effectively inhibit neointimal hyperplasia within the first year, thereby reducing the need for repeat revascularization. However, a delayed pattern of restenosis might be more prominent in drug-eluting stents compared to bare metal stents (BMSs). The extent of restenosis of paclitaxel-eluting stents (PESs) long term after implantation in acute ST-segment elevation myocardial infarction is currently unknown. The present study was designed to evaluate very late luminal loss (VLLL) of PESs used in ST-segment elevation myocardial infarction compared to BMSs. A total of 116 patients (61 with PESs and 55 with BMSs) initially included in the Paclitaxel Eluting Stent Versus Conventional Stent in ST-segment Elevation Myocardial Infarction (PASSION) trial and who were free from previous lesion failure underwent angiographic follow-up. Off-line quantitative coronary analysis of the angiogram immediately after stent implantation and at follow-up was performed. The primary end point was VLLL within the stent. The presence of binary restenosis was defined as diameter stenosis >50% as a secondary end point. The mean interval between stent implantation and follow-up was 4.1 ± 0.5 years in both stent groups. In-stent VLLL was 0.12 mm (interquartile range -0.03 to 0.42) in the PES group versus 0.30 mm (interquartile range 0.08 to 0.69) in the BMS group (p = 0.011). In-segment binary restenosis was found in 4 patients (6.6%) with a PES and 6 patients (10.9%) with a BMS (p = 0.40). In conclusion, angiographic follow-up 4 years after implantation in ST-segment elevation myocardial infarction showed that in patients prospectively randomized to PESs or BMSs, VLLL was low in both stent groups. PESs were associated with lower VLLL than BMSs, and the observed rate of binary restenosis was not significantly different between the 2 stent groups.

  20. 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

  1. Acute gouty arthritis complicated with acute ST elevation myocardial infarction is independently associated with short- and long-term adverse non-fatal cardiac events.

    PubMed

    Liu, Kuan-Liang; Lee, Hsin-Fu; Chou, Shing-Hsien; Lin, Yen-Chen; Lin, Chia-Pin; Wang, Chun-Li; Chang, Chi-Jen; Hsu, Lung-An

    2014-01-01

    Large epidemiologic studies have associated gouty arthritis with the risk of coronary heart disease. However, there has been a lack of information regarding the outcomes for patients who have gout attacks during hospitalization for acute myocardial infarction. We reviewed the data of 444 consecutive patients who were admitted to our hospital between 2005 and 2008 due to acute ST elevation myocardial infarction (STEMI). The clinical outcomes were compared between patients with gout attack and those without. Of the 444, 48 patients with acute STEMI developed acute gouty arthritis during hospitalization. The multivariate analysis identified prior history of gout and estimated glomerular filtration rate as independent risk factors of gout attack for patients with acute STEMI (odds ratio (OR) 21.02, 95 % CI 2.96-149.26, p = 0.002; OR 0.92, 95 % CI 0.86-0.99, p = 0.035, respectively). The in-hospital mortality and duration of hospital stay did not differ significantly between the gouty group and the non-gouty group (controls). During a mean follow-up of 49 ± 28 months, all-cause mortality and stroke were similar for both groups. Multivariate Cox regression showed that gout attack was independently associated with short- and long-term adverse non-fatal cardiac events (hazard ratio (HR) 1.88, 95 % CI 1.09-3.24, p = 0.024; HR 1.82, 95 % CI 1.09-3.03, p = 0.022, respectively). Gout attack among patients hospitalized due to acute STEMI was independently associated with short-term and long-term rates of adverse non-fatal cardiac events.

  2. Evaluation of the Effect of Concurrent Chronic Total Occlusion and Successful Staged Revascularization on Long-Term Mortality in Patients with ST-Elevation Myocardial Infarction

    PubMed Central

    Shi, Guoxiang; He, Pengcheng; Liu, Yuanhui; Lin, Yaowang; Yang, Xing; Chen, Jiyuan; Zhou, Yingling; Tan, Ning

    2014-01-01

    Aims. To investigate the impact of chronic total occlusion (CTO) in non-infarct-related artery (IRA) on the long-term prognosis and evaluate the clinical significance of staged revascularization in patients with ST-segment elevation myocardial infarction (STEMI). Methods. 1266 STEMI patients with primary percutaneous coronary intervention (PCI) were categorized as single-vessel disease (SVD), multivessel disease (MVD) without and with CTO. We study the clinical outcomes of patients after primary PCI in the following 3 years. Additionally, patients with CTO received staged revascularization, and major adverse cardiac events (MACE) during 3-year follow-up were recorded. Results. Presence of CTO was a predictor of both early mortality [hazard ratio (HR) 3.4, 95% confidence interval (CI) 2.4–4.5, P < 0.01] and late mortality (HR 1.9, 95% CI 1.4–3.6, P < 0.01), whereas MVD without CTO was only a predictor of early mortality (HR 1.7, 95% CI 1.3–2.3, P < 0.05). In CTO group, 100 patients had successful CTO recanalization, and 48 patients failed. During 3-year follow-up, patients with failed procedure had higher cardiac mortality (22.9% versus 9.0%, P = 0.020) and lower MACE-free survival (50.0% versus 72.0%, P = 0.009) compared to patients with successful procedure. Conclusion. The presence of CTO and not MVD alone is associated with long-term mortality. Successful revascularization of CTO in the non-IRA is associated with improved clinical outcomes in patients with STEMI undergoing primary PCI. PMID:24790581

  3. The obesity paradox, extreme obesity, and long-term outcomes in older adults with ST-segment elevation myocardial infarction: results from the NCDR.

    PubMed

    Neeland, Ian J; Das, Sandeep R; Simon, DaJuanicia N; Diercks, Deborah B; Alexander, Karen P; Wang, Tracy Y; de Lemos, James A

    2017-07-01

    To investigate the obesity paradox and association of extreme obesity with long-term outcomes among older ST-segment elevation myocardial infarction (STEMI) patients. Nineteen thousand four hundred and ninety-nine patients ≥65 years with STEMI surviving to hospital discharge in NCDR ACTION Registry-GWTG linked to Centers for Medicare and Medicaid Services outcomes between 2007 and 2012 were stratified by body mass index (BMI) (kg/m2) into normal weight (18.5-24.9), overweight (25-29.9), class I (30-34.9), class II (35-39.9), and class III/extreme obese (≥40) categories. Multivariable-adjusted associations were evaluated between BMI categories and mortality by Cox proportional hazards models, and days alive and out of hospital (DAOH) by generalized estimating equations, within 3 years after discharge. Seventy percent of patients were overweight/obese and 3% extremely obese. Normal weight patients were older and more likely to smoke; while extremely obese patients were younger and more likely to be female and black, with lower socioeconomic status and more comorbidity (P ≤ 0.001). A U-shaped association was observed between BMI categories and mortality: patients with class I obesity were at lowest risk, while normal weight [hazard ratio (HR) 1.30, 95% confidence interval (CI) 1.15-1.47] and extremely obese patients (HR 1.33, 95% CI 1.02-1.74) had higher mortality. Normal weight [odds ratio (OR) 0.79, 95% CI 0.68-0.90] and extremely obese (OR 0.73, 95% CI 0.54-0.99) individuals also had lower odds of DAOH. Mild obesity is associated with lower long-term risk in older STEMI patients, while normal weight and extreme obesity are associated with worse outcomes. These findings highlight hazards faced by an increasing number of older individuals with normal weight or extreme obesity and cardiovascular disease.

  4. 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 .

  5. 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.

  6. Coronary Artery Dominance and Long-term Prognosis in Patients With ST-segment Elevation Myocardial Infarction Treated With Primary Angioplasty.

    PubMed

    Abu-Assi, Emad; Castiñeira-Busto, María; González-Salvado, Violeta; Raposeiras-Roubin, Sergio; Riziq-Yousef Abumuaileq, Rami; Peña-Gil, Carlos; Rigueiro-Veloso, Pedro; Ocaranza, Raimundo; García-Acuña, José María; González-Juanatey, José Ramón

    2016-01-01

    The long-term prognostic significance of coronary artery dominance pattern in patients with ST-segment elevation myocardial infarction is poorly characterized. We investigated the prognosis of such patients according to whether they had right dominance, left dominance, or codominance. This was a retrospective study of 767 patients, who were admitted to hospital between 2007 and 2012 with ST-segment elevation myocardial infarction and treated with primary percutaneous coronary intervention. We determined the effect of the coronary dominance pattern on all-cause mortality and readmission for infarction, adjusting for mortality as a competing event. A total of 80.9% of patients had right coronary dominance, and 8.6% had left coronary dominance. Over 40.8 months' [interquartile range, 21.9-58.3 months] follow-up, 118 (15.4%) deaths were recorded, of which 39 (5.1%) were in hospital. Mortality for right dominance, left dominance, and codominance was 7.1%, 36.4%, and 13.8% (P ˂ .001), respectively. Cause of death was cardiovascular in 7.1%, 21.2%, and 2.4%. On Cox multivariate analysis, left dominance was significantly associated with mortality (hazard ratio = 1.76; P = .02). Taking "coronary dominance" into account in prediction of risk of death improved the discrimination and calibration capacity of GRACE (Global Registry of Acute Coronary Events) scoring. At follow-up, 9.3% (71 patients) had reinfarction. On multivariate analysis, left dominance was an independent predictor of reinfarction (subhazard ratio = 2.06; P = .01). In ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention, left coronary artery dominance confers a higher risk of death and reinfarction than right coronary artery dominance, and should be included in prognostic stratification. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  7. Long-term facilitation of ventilation and genioglossus muscle activity is evident in the presence of elevated levels of carbon dioxide in awake humans.

    PubMed

    Harris, Daniel P; Balasubramaniam, Arvind; Badr, M Safwan; Mateika, Jason H

    2006-10-01

    We hypothesized that long-term facilitation (LTF) of minute ventilation and peak genioglossus muscle activity manifests itself in awake healthy humans when carbon dioxide is sustained at elevated levels. Eleven subjects completed two trials. During trial 1, baseline carbon dioxide levels were maintained during and after exposure to eight 4-min episodes of hypoxia. During trial 2, carbon dioxide was sustained 5 mmHg above baseline levels during exposure to episodic hypoxia. Seven subjects were exposed to sustained elevated levels of carbon dioxide in the absence of episodic hypoxia, which served as a control experiment. Minute ventilation was measured during trial 1, trial 2, and the control experiment. Peak genioglossus muscle activity was measured during trial 2. Minute ventilation during the recovery period of trial 1 was similar to baseline (9.3 +/- 0.5 vs. 9.2 +/- 0.7 l/min). Likewise, minute ventilation remained unchanged during the control experiment (beginning vs. end of control experiment, 14.4 +/- 1.7 vs. 14.7 +/- 1.4 l/min). In contrast, minute ventilation and peak genioglossus muscle activity during the recovery period of trial 2 was greater than baseline (minute ventilation: 28.4 +/- 1.7 vs. 19.6 +/- 1.0 l/min, P < 0.001; peak genioglossus activity: 1.6 +/- 0.3 vs. 1.0 fraction of baseline, P < 0.001). We conclude that exposure to episodic hypoxia is necessary to induce LTF of minute ventilation and peak genioglossus muscle activity and that LTF is only evident in awake humans in the presence of sustained elevated levels of carbon dioxide.

  8. Gene expression patterns of trembling aspen trees following long-term exposure to interacting elevated CO2 and tropospheric O3.

    PubMed

    Gupta, P; Duplessis, S; White, H; Karnosky, D F; Martin, F; Podila, G K

    2005-07-01

    Expression of 4600 poplar expressed sequence tags (ESTs) was studied over the 2001-2002 growing seasons using trees of the moderately ozone (O(3))-tolerant trembling aspen (Populus tremuloides) clone 216 exposed to elevated CO(2) and/or O(3) for their entire 5-yr life history. Based on replication of the experiment in years 2001 and 2002, 238 genes showed qualitatively similar expression in at least one treatment and were retained for analysis. Of these 238 genes, 185 were significantly regulated (1.5-fold) from one year to the other in at least one treatment studied. Less than 1% of the genes were regulated 2-fold or more. In the elevated CO(2) treatment, relatively small numbers of genes were up-regulated, whereas in the O(3) treatment, higher expression of many signaling and defense-related genes and lower expression of several photosynthesis and energy-related genes were observed. Senescence-associated genes (SAGs) and genes involved in the flavonoid pathway were also up-regulated under O(3), with or without CO(2) treatment. Interestingly, the combined treatment of CO(2) plus O(3) resulted in the differential expression of genes that were not up-regulated with individual gas treatments. This study represents the first investigation into gene expression following long-term exposure of trees to the interacting effects of elevated CO(2) and O(3) under field conditions. Patterns of gene-specific regulation described in this study correlated with previously published physiological responses of aspen clone 216.

  9. 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.

  10. 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.

  11. Long-term visibility variation in Athens (1931-2013): a proxy for local and regional atmospheric aerosol loads

    NASA Astrophysics Data System (ADS)

    Founda, Dimitra; Kazadzis, Stelios; Mihalopoulos, Nikolaos; Gerasopoulos, Evangelos; Lianou, Maria; Raptis, Panagiotis I.

    2016-09-01

    This study explores the interdecadal variability and trends of surface horizontal visibility at the urban area of Athens from 1931 to 2013, using the historical archives of the National Observatory of Athens (NOA). A prominent deterioration of visibility in the city was detected, with the long-term linear trend amounting to -2.8 km decade-1 (p < 0.001), over the entire study period. This was not accompanied by any significant trend in relative humidity or precipitation over the same period. A slight recovery of visibility levels seems to be established in the recent decade (2004-2013). It was found that very good visibility (> 20 km) occurred at a frequency of 34 % before the 1950s, while this percentage drops to just 2 % during the decade 2004-2013. The rapid impairment of the visual air quality in Athens around the 1950s points to the increased levels of air pollution on a local and/or regional scale, related to high urbanization rates and/or increased anthropogenic emissions on a global scale at that period. Visibility was found to be negatively/positively correlated with relative humidity/wind speed, the correlation being statistically valid at certain periods. Wind regime and mainly wind direction and corresponding air mass origin were found to highly control visibility levels in Athens. The comparison of visibility variation in Athens and at a non-urban reference site on Crete island revealed similar negative trends over the common period of observations. This suggests that apart local sources, visibility in Athens is highly determined by aerosol load of regional origin. AVHRR and MODIS satellite-derived aerosol optical depth (AOD) retrievals over Athens and surface measurements of PM10 confirmed the relation of visibility to aerosol load.

  12. 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.

  13. 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.

  14. 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

  15. Environmental variation is directly responsible for short- but not long-term variation in forest-atmosphere carbon exchange

    Treesearch

    Andrew D. Richardson; David Y. Hollinger; John D. Aber; Scott V. Ollinger; Bobby H. Braswell

    2007-01-01

    Tower-based eddy covariance measurements of forest-atmosphere carbon dioxide (CO2) exchange from many sites around the world indicate that there is considerable year-to-year variation in net ecosystem exchange (NEE). Here, we use a statistical modeling approach to partition the interannual variability in NEE (and its component fluxes, ecosystem...

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

    Treesearch

    John E Drake; Anne Gallet-Budynek; Kirsten S Hofmockel; Emily S Bernhardt; Sharon A Billings; Robert B Jackson; Kurt S Johnsen; al. et.

    2011-01-01

    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...

  17. Long-term trend of chemical composition of atmospheric precipitation at a regional background station in Northern China.

    PubMed

    Pu, Weiwei; Quan, Weijun; Ma, Zhiqiang; Shi, Xuefeng; Zhao, Xiujuan; Zhang, Linna; Wang, Zhenfa; Wang, Wenyan

    2017-02-15

    Understanding the trend of chemical composition of precipitation is of great importance for air pollution control strategies in Northern China. A comprehensive study on the long-term chemical compositions of precipitation was carried out from 2003 to 2014 at the Shangdianzi (SDZ) regional background station in northern China. All samples were analyzed for pH, electrical conductivity and major ions (F(-), Cl(-), NO3(-), SO4(2-), NH4(+), Mg(2+), Ca(2+), K(+) and Na(+)). The average pH during this period was 4.53±0.35, which is considerably lower than those reported in other background stations in China (Linan, Waliguan and Longfengshan). NH4(+), SO4(2-), Ca(2+) and NO3(-) were the dominant ions in precipitation, with concentrations (volume-weighted mean) of 212.99μeqL(-1), 200.20μeqL(-1), 116.88μeqL(-1) and 98.56μeqL(-1), respectively. The ion concentrations at SDZ were much higher than those of other background stations and megacities in China. A significantly increasing trend was observed for NO3(-) (7.26%year(-1)), and a decreasing trend was observed for SO4(2-)/NO3(-), suggesting that the precipitation of SDZ evolved from a sulfuric acid type to a mixed type dominated by both sulfuric and nitric acid. The source identification indicated that SO4(2-), NO3(-), NH4(+) and F(-) were dominated by secondary sources, Mg(2+), Ca(2+) and Na(+) mostly originated from natural sources, and K(+) and Cl(-) probably associated with anthropogenic sources. Long-range transport of air masses could influence the acidity, electrical conductivity and ion concentrations of precipitation at SDZ. The higher acidity and ion concentrations mainly occurred in the southerly and westerly trajectory pathways and partially in northwest pathways. Anthropogenic pollutants and crustal sources along these pathways were significant contributors to the chemical composition of precipitation in SDZ.

  18. Long-Term Global Distributions of Mesoscale Variations in Atmospheric Radio Refraction Obtained from the GPS Champ Satellite Data

    NASA Astrophysics Data System (ADS)

    Gavrilov, N. M.; Manuilova, R. O.

    2016-12-01

    We obtain average global distributions of the variances of the mesoscale variations in the atmospheric radio-refraction index (refractive index) at altitudes of 5-35 km from the data of the radio-occultation experiments performed during operation of the low-orbit GPS CHAMP satellite in the period 2001-2009. The filtering of the vertical profiles of the radio-refraction index allows one to determine the variances of the variations with vertical scales below 8 km. The latitudinal-temporal distributions of the zonal-mean variances of the index demonstrate significant interannual variations at various altitudes. Seasonal variations in the variances of radio refraction are studied. Quasi-biennial oscillations at low latitudes are revealed. Acoustic-gravity waves and turbulent and convective motions in the atmosphere can cause a spread of the radio-refraction index.

  19. 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.

  20. Long-term atmospheric nutrient inputs to the Eastern Mediterranean: sources, solubility and comparison with riverine inputs

    NASA Astrophysics Data System (ADS)

    Koçak, M.; Kubilay, N.; Tuǧrul, S.; Mihalopoulos, N.

    2010-07-01

    Aerosol and rain samples were collected at a rural site located on the coastline of the Eastern Mediterranean, Erdemli, Turkey between January 1999 and December 2007. Riverine sampling was carried out at five Rivers (Ceyhan, Seyhan, Göksu, Berdan and Lamas) draining into the Northeastern Levantine Basin (NLB) between March 2002 and July 2007. Samples were analyzed for macronutrients of phosphate, silicate, nitrate and ammonium (PO43-, Sidiss, NO3- and NH4+). Phosphate and silicate in aerosol and rainwater showed higher and larger variation during the transitional period (March-May, September) when air flows predominantly originate from North Africa and Middle East/Arabian Peninsula. Deficiency of alkaline material were found to be the main reason of the acidic rain events whilst high pH values (>7) were associated with high Sidiss concentrations due to sporadic dust events. In general, lowest nitrate and ammonium concentrations in aerosol and rainwater were associated with air flow from the Mediterranean Sea. Unlike NO3- and NH4+ (Dissolved Inorganic Nitrogen, DIN), there were statistical differences for PO43- and Sidiss solubilities in sea-water and pure-water. Solubilities of PO43- and Sidiss were found to be related with air mass back trajectories and pH. Comparison of atmospheric with riverine fluxes demonstrated that DIN and PO43- fluxes to NLB were dominated by atmosphere (~90% and ~60% respectively) whereas the input of Si was mainly derived from riverine runoff (~90%). N/P ratios (atmosphere ~233; riverine ~28) revealed that NLB receives excessive amounts of DIN and this unbalanced P and N inputs may provoke even more phosphorus deficiency. Molar Si/N ratios (atmosphere + riverine) suggested Si limitation which might cause a switch from diatom dominated phytoplankton communities to non-siliceous populations in NLB.

  1. Comparison of drug-eluting stents to bare-metal stents in ST-elevation myocardial infarction in long-term follow-up.

    PubMed

    Kübler, Piotr; Jankowska, Ewa A; Ferenc, Mirosław; Ponikowski, Piotr; Banasiak, Waldemar; Reczuch, Krzysztof

    2013-01-01

    Recent data from "real world" registries and some randomised trials concerning the safety and efficacy of drug-eluting stents (DES) in patients with acute ST-elevation myocardial infarction (STEMI) are equivocal. We sought to compare DES with bare-metal stents (BMS) in STEMI patients treated with primary percutaneous coronary intervention in terms of safety and efficacy parameters in long-term follow-up. 895 consecutive STEMI patients admitted between 2003 and 2006 were included in this observational study. The clinical and procedural characteristic as well as long-term outcome of 327 patients treated with DES were compared with 568 patients treated with BMS. Combined primary endpoint consisted of: death, myocardial infarction (MI) and target vessel revascularisation (TVR). Age, sex, risk factors, presence of 3-vessel disease, left ventricular ejection fraction and the use of IIb/IIIa antagonist were comparable in both groups. During a mean follow-up of 570 ± 490 days, the mortality rate was 8.9% in the DES group vs. 15.5% in the BMS group (p = 0.005). In the DES group, lower incidences of both death and MI (9.5% vs. 16%, p = 0.006) as well as the combined endpoint of death, MI and TVR (19.3% vs. 31.3%, p < 0.001) were recorded. Target lesion revascularisation was more frequently performed in the BMS group (13.4% vs. 8.6%, p = 0.03). However, patients who received BMS more frequently had history of MI and coronary interventions, Killip class > 1 on admission, lower level of haemoglobin and HDL-cholesterol and higher level of troponin than those who received DES. After adjustment, the use of BMS was no longer significantly associated with worse clinical outcome with a trend in favour of DES. The only independent factor associated with increased risk of the combined endpoint was the Killip class > 1 (p = 0.003). In STEMI patients, DES are not inferior in comparison to BMS in terms of safety and efficacy parameters and seem to be associated with a lower rate of

  2. 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.

  3. Long-Term Observations of Atmospheric CO2, O3 and BrO over the Transitioning Arctic Ocean Pack-ice: The O-Buoy Chemical Network

    NASA Astrophysics Data System (ADS)

    Matrai, P.

    2016-02-01

    Autonomous, sea ice-tethered O-Buoys have been deployed (2009-2016) across the Arctic sea ice for long-term atmospheric measurements (http://www.o-buoy.org). O-Buoys (15) provide in-situ concentrations of three sentinel atmospheric chemicals, ozone, CO2 and BrO, as well as meteorological parameters and imagery, over the frozen ocean. O-Buoys were designed to transmit daily data over a period of 2 years while deployed in sea ice, as part of automated ice-drifting stations that include snow/ice measurement systems (e.g. Ice Mass Balance buoys) and oceanographic measurements (e.g. Ice Tethered Profilers). Seasonal changes in Arctic atmospheric chemistry are influenced by changes in the characteristics and presence of the sea ice vs. open water as well as air mass trajectories, especially during the winter-spring and summer-fall transitions when sea ice is melting and freezing, respectively. The O-Buoy Chemical Network provides the unique opportunity to observe these transition periods in real-time with high temporal resolution, and to compare them with those collected on land-based monitoring stations located. Due to the logistical challenges of measurements over the Arctic Ocean region, most long term, in-situ observations of atmospheric chemistry have been made at coastal or island sites around the periphery of the Arctic Ocean, leaving large spatial and temporal gaps that O-Buoys overcome. Advances in floatation, communications, power management, and sensor hardware have been made to overcome the challenges of diminished Arctic sea ice. O-Buoy data provide insights into enhanced seasonal, interannual and spatial variability in atmospheric composition, atmospheric boundary layer control on the amount of halogen activation, enhancement of the atmospheric CO2 signal over the more variable and porous pack ice, and to develop an integrated picture of the coupled ocean/ice/atmosphere system. As part of the Arctic Observing Network, we provide data to the community (www.aoncadis.org).

  4. GRACE AOD1B Product Release 06: Long-Term Consistency and the Treatment of Atmospheric Tides

    NASA Astrophysics Data System (ADS)

    Dobslaw, Henryk; Bergmann-Wolf, Inga; Dill, Robert; Poropat, Lea; Flechtner, Frank

    2017-04-01

    The GRACE satellites orbiting the Earth at very low altitudes are affected by rapid changes in the Earth's gravity field caused by mass redistribution in atmosphere and oceans. To avoid temporal aliasing of such high-frequency variability into the final monthly-mean gravity fields, those effects are typically modelled during the numerical orbit integration by appling the 6-hourly GRACE Atmosphere and Ocean De-Aliasing Level-1B (AOD1B) a priori model. In preparation of the next GRACE gravity field re-processing currently performed by the GRACE Science Data System, a new version of AOD1B has been calculated. The data-set is based on 3-hourly surface pressure anomalies from ECMWF that have been mapped to a common reference orography by means of ECMWF's mean sea-level pressure diagnostic. Atmospheric tides as well as the corresponding oceanic response at the S1, S2, S3, and L2 frequencies and its annual modulations have been fitted and removed in order to retain the non-tidal variability only. The data-set is expanded into spherical harmonics complete up to degree and order 180. In this contribution, we will demonstrate that AOD1B RL06 is now free from spurious jumps in the time-series related to occasional changes in ECMWF's operational numerical weather prediction system. We will also highlight the rationale for separating tidal signals from the AOD1B coefficients, and will finally discuss the current quality of the AOD1B forecasts that have been introduced very recently for GRACE quicklook or near-realtime applications.

  5. Atmospheric nutrient inputs to the northern levantine basin from a long-term observation: sources and comparison with riverine inputs

    NASA Astrophysics Data System (ADS)

    Koçak, M.; Kubilay, N.; Tuğrul, S.; Mihalopoulos, N.

    2010-12-01

    Aerosol and rainwater samples have been collected at a rural site located on the coastline of the Eastern Mediterranean, Erdemli, Turkey between January 1999 and December 2007. Riverine sampling was carried out at five Rivers (Ceyhan, Seyhan, Göksu, Berdan and Lamas) draining into the Northeastern Levantine Basin (NLB) between March 2002 and July 2007. Samples have been analyzed for macronutrients of phosphate, silicate, nitrate and ammonium (PO43-, Sidiss, NO3- and NH4+). Phosphate and silicate in aerosol and rainwater showed higher and larger variations during the transitional period when air flows predominantly originate from North Africa and Middle East/Arabian Peninsula. Deficiency of alkaline material have been found to be the main reason of the acidic rain events whilst high pH values (>7) have been associated with high Sidiss concentrations due to sporadic dust events. In general, lowest nitrate and ammonium concentrations in aerosol and rainwater have been associated with air flow from the Mediterranean Sea. Comparison of atmospheric with riverine fluxes demonstrated that DIN and PO43- fluxes to NLB have been dominated by atmosphere (~90% and ~60% respectively) whereas the input of Si was mainly derived from riverine runoff (~90%). N/P ratios in the atmospheric deposition (233); riverine discharge (28) revealed that NLB receives excessive amounts of DIN and this unbalanced P and N inputs may provoke even more phosphorus deficiency. Observed molar Si/N ratio suggested Si limitation relative to nitrogen might cause a switch from diatom dominated communities to non-siliceous populations particularly at coastal NLB.

  6. 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.

  7. 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.

  8. 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

    2014-11-20

    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.

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

    PubMed Central

    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 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. PMID:25409781

  10. 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.

  11. Permian-Triassic boundary interval as a model for forcing marine ecosystem collapse by long-term atmospheric oxygen drop

    NASA Astrophysics Data System (ADS)

    Weidlich, O.; Kiessling, W.; Flügel, E.

    2003-11-01

    Ecological traits of reefs across the Permian-Triassic boundary interval coincide with a modeled decline of atmospheric oxygen throughout the Permian Period. Selective extinction and recovery patterns within the reef system are observed both at the end of the middle Permian (end-Guadalupian) and at the Permian-Triassic boundary. The end-Guadalupian event selectively affected corals and broke down the cool-water carbonate factory. Sponges, however, were largely unaffected and bloomed in reefs toward the end of the Permian. The end-Permian total destruction of the metazoan reef system only left behind poorly diverse microbial communities. The temporal reef patterns are thus similar to spatial patterns of modern benthic communities approaching oxygen minimum zones. This observation suggests that a decline in oxygen concentrations was at least partly involved in the destruction of reefs, even where there is no direct evidence of oceanic anoxia.

  12. New Insights in the Long-Term Atmospheric Corrosion Mechanisms of Low Alloy Steel Reinforcements of Cultural Heritage Buildings

    PubMed Central

    Bouchar, Marie; Dillmann, Philippe; Neff, Delphine

    2017-01-01

    Reinforcing clamps made of low alloy steel from the Metz cathedral and corroded outdoors during 500 years were studied by OM, FESEM/EDS, and micro-Raman spectroscopy. The corrosion product layer is constituted of a dual structure. The outer layer is mainly constituted of goethite and lepidocrocite embedding exogenous elements such as Ca and P. The inner layer is mainly constituted of ferrihydrite. The behaviour of the inner layer under conditions simulating the wetting stage of the RH wet/dry atmospheric corrosion cycle was observed by in situ micro-Raman spectroscopy. The disappearance of ferrihydrite near the metal/oxide interface strongly suggests a mechanism of reductive dissolution caused by the oxidation of the metallic substrate and was observed for the first time in situ on an archaeological system. PMID:28773030

  13. New Insights in the Long-Term Atmospheric Corrosion Mechanisms of Low Alloy Steel Reinforcements of Cultural Heritage Buildings.

    PubMed

    Bouchar, Marie; Dillmann, Philippe; Neff, Delphine

    2017-06-19

    Reinforcing clamps made of low alloy steel from the Metz cathedral and corroded outdoors during 500 years were studied by OM, FESEM/EDS, and micro-Raman spectroscopy. The corrosion product layer is constituted of a dual structure. The outer layer is mainly constituted of goethite and lepidocrocite embedding exogenous elements such as Ca and P. The inner layer is mainly constituted of ferrihydrite. The behaviour of the inner layer under conditions simulating the wetting stage of the RH wet/dry atmospheric corrosion cycle was observed by in situ micro-Raman spectroscopy. The disappearance of ferrihydrite near the metal/oxide interface strongly suggests a mechanism of reductive dissolution caused by the oxidation of the metallic substrate and was observed for the first time in situ on an archaeological system.

  14. Short- and long-term prognostic significance of ST-segment elevation in lead aVR in patients with non-ST-segment elevation acute coronary syndrome.

    PubMed

    Taglieri, Nevio; Marzocchi, Antonio; Saia, Francesco; Marrozzini, Cinzia; Palmerini, Tullio; Ortolani, Paolo; Cinti, Laura; Rosmini, Stefania; Vagnarelli, Fabio; Alessi, Laura; Villani, Caterina; Scaramuzzino, Giuseppe; Gallelli, Ilaria; Melandri, Giovanni; Branzi, Angelo; Rapezzi, Claudio

    2011-07-01

    We sought to evaluate the prognostic significance of ST-segment elevation (STE) in lead aVR in unselected patients with non-STE acute coronary syndrome (NSTE-ACS). We enrolled 1,042 consecutive patients with NSTE-ACS. Patients were divided into 5 groups according to the following electrocardiographic (ECG) patterns on admission: (1) normal electrocardiogram or no significant ST-T changes, (2) inverted T waves, (3) isolated ST deviation (ST depression [STD] without STE in lead aVR or transient STE), (4) STD plus STE in lead aVR, and (5) ECG confounders (pacing, right or left bundle branch block). The main angiographic end point was left main coronary artery (LM) disease as the culprit artery. Clinical end points were in-hospital and 1-year cardiovascular death defined as the composite of cardiac death, fatal stroke, and fatal bleeding. Prevalence of STD plus STE in lead aVR was 13.4%. Rates of culprit LM disease and in-hospital cardiovascular death were 8.1% and 3.8%, respectively. On multivariable analysis, patients with STD plus STE in lead aVR (group 4) showed an increased risk of culprit LM disease (odds ratio 4.72, 95% confidence interval [CI] 2.31 to 9.64, p <0.001) and in-hospital cardiovascular mortality (odds ratio 5.58, 95% CI 2.35 to 13.24, p <0.001) compared to patients without any ST deviation (pooled groups 1, 2, and 5), whereas patients with isolated ST deviation (group 3) did not. At 1-year follow-up 127 patients (12.2%) died from cardiovascular causes. On multivariable analysis, STD plus STE in lead aVR was a stronger independent predictor of cardiovascular death (hazard ratio 2.29, 95% CI 1.44 to 3.64, p <0.001) than isolated ST deviation (hazard ratio 1.52, 95% CI 0.98 to 2.36, p = 0.06). In conclusion, STD plus STE in lead aVR is associated with high-risk coronary lesions and predicts in-hospital and 1-year cardiovascular deaths in patients with NSTE-ACS. Therefore, this promptly available ECG pattern could be useful to improve risk

  15. Usefulness of biomarkers for predicting long-term mortality in patients with diabetes mellitus and non-ST-elevation acute coronary syndromes (a GUSTO IV substudy).

    PubMed

    James, Stefan K; Lindahl, Bertil; Timmer, Jorik R; Ottervanger, Jan Paul; Siegbahn, Agneta; Stridsberg, Mats; Armstrong, Paul; Califf, Robert; Wallentin, Lars; Simoons, Maarten L

    2006-01-15

    The present study evaluated whether biomarkers of ischemia, inflammation, myocardial damage, and dysfunction are equally useful in patients who have diabetes mellitus (DM) for prediction of cardiac events in non-ST-elevation acute coronary syndrome (ACS). DM was present in 1,677 of 7,800 patients (21.5%) who had non-ST-elevation ACS and were included in the Fourth Global Utilization of Strategies To Open Occluded Arteries (GUSTO IV) trial. Creatinine, N-terminal pro-B-type natriuretic peptide (NT-pro-BNP), troponin T, C-reactive protein, and interleukin-6 were analyzed in serum samples that were obtained at a median of 9.5 hours from symptom onset. One-year mortality rates were 13.5% among patients who had DM (n = 227) and 6.9% among those who did not (n = 418, p < 0.001). The median level of NT-pro-BNP was 2 times as high in patients who had DM, whereas troponin T levels did not differ by DM status. Mortality increased with ascending quartiles of NT-pro-BNP, with 1-year mortality rates of 3.9% (n = 11) in the bottom quartile and 29% (n = 103) in the top quartile. In multivariable analyses, factors that were predictive of 1-year mortality in patients who did not have DM were also significant for those who did. Presence of ST depression > 0.5 mm had the highest odds ratio of 2.3 (95% confidence interval 1.2 to 4.6). NT-pro-BNP levels > 669 ng/L (odds ratio 2.0, 95% confidence interval 1.1 to 3.6) and interleukin-6 levels > 10 ng/L (odds ratio 1.9, 95% confidence interval 1.2 to 3.0) were significant biomarker predictors. In conclusion, DM confers a high long-term mortality in non-ST-elevation ACS. Despite a larger proportion of ST depression and increased levels of NT-pro-BNP and interleukin-6 at admission, these factors provide independent prognostic information that may improve risk stratification and guidance of treatment.

  16. Endothelial Dysfunction After ST-segment Elevation Myocardial Infarction and Long-term Outcome: A Study With Reactive Hyperemia Peripheral Artery Tonometry.

    PubMed

    Kandhai-Ragunath, Jasveen J; Doggen, Carine J M; Jørstad, Harald T; Doelman, Cees; de Wagenaar, Bjorn; IJzerman, Maarten J; Peters, Ron J G; von Birgelen, Clemens

    2016-07-01

    Long-term data on the relationship between endothelial dysfunction after ST-segment elevation myocardial infarction and future adverse clinical events are scarce. The aim of this study was to noninvasively assess whether endothelial dysfunction 4 weeks to 6 weeks after primary percutaneous coronary intervention for acute ST-segment elevation myocardial infarction predicts future clinical events. This prospective cohort study was performed in 70 patients of the RESPONSE randomized trial, who underwent noninvasive assessment of endothelial function 4 weeks to 6 weeks after primary percutaneous coronary intervention. Endothelial function was measured by the reactive hyperemia peripheral artery tonometry method; an index<1.67 identified endothelial dysfunction. The reactive hyperemia peripheral artery tonometry index measured on average 1.90±0.58. A total of 35 (50%) patients had endothelial dysfunction and 35 (50%) patients had normal endothelial function. Periprocedural "complications" (eg, cardiogenic shock, total atrioventricular block) were more common in patients with endothelial dysfunction than in those without (25.7% vs 2.9%; P<.01). During 4.0±1.7 years of follow-up, 20 (28.6%) patients had major adverse cardiovascular events: events occurred in 9 (25.7%) patients with endothelial dysfunction and in 11 (31.5%) patients with normal endothelial function (P=.52). There was an association between the prevalence of diabetes mellitus at baseline and the occurrence of major adverse cardiovascular events during follow-up (univariate analysis: hazard ratio=2.8; 95% confidence interval, 1.0-7.8; P<.05), and even in multivariate analyses the risk appeared to be increased, although not significantly (multivariate analysis: hazard ratio=2.5; 95% confidence interval, 0.8-7.5). In this series of patients who survived an ST-segment elevation myocardial infarction, endothelial dysfunction, as assessed by reactive hyperemia peripheral artery tonometry 4 weeks to 6 weeks

  17. Impact of Clinical Presentation (Stable Angina Pectoris vs Unstable Angina Pectoris or Non-ST-Elevation Myocardial Infarction vs ST-Elevation Myocardial Infarction) on Long-Term Outcomes in Women Undergoing Percutaneous Coronary Intervention With Drug-Eluting Stents.

    PubMed

    Giustino, Gennaro; Baber, Usman; Stefanini, Giulio Giuseppe; Aquino, Melissa; Stone, Gregg W; Sartori, Samantha; Steg, Philippe Gabriel; Wijns, William; Smits, Pieter C; Jeger, Raban V; Leon, Martin B; Windecker, Stephan; Serruys, Patrick W; Morice, Marie-Claude; Camenzind, Edoardo; Weisz, Giora; Kandzari, David; Dangas, George D; Mastoris, Ioannis; Von Birgelen, Clemens; Galatius, Soren; Kimura, Takeshi; Mikhail, Ghada; Itchhaporia, Dipti; Mehta, Laxmi; Ortega, Rebecca; Kim, Hyo-Soo; Valgimigli, Marco; Kastrati, Adnan; Chieffo, Alaide; Mehran, Roxana

    2015-09-15

    The long-term risk associated with different coronary artery disease (CAD) presentations in women undergoing percutaneous coronary intervention (PCI) with drug-eluting stents (DES) is poorly characterized. We pooled patient-level data for women enrolled in 26 randomized clinical trials. Of 11,577 women included in the pooled database, 10,133 with known clinical presentation received a DES. Of them, 5,760 (57%) had stable angina pectoris (SAP), 3,594 (35%) had unstable angina pectoris (UAP) or non-ST-segment-elevation myocardial infarction (NSTEMI), and 779 (8%) had ST-segment-elevation myocardial infarction (STEMI) as clinical presentation. A stepwise increase in 3-year crude cumulative mortality was observed in the transition from SAP to STEMI (4.9% vs 6.1% vs 9.4%; p <0.01). Conversely, no differences in crude mortality rates were observed between 1 and 3 years across clinical presentations. After multivariable adjustment, STEMI was independently associated with greater risk of 3-year mortality (hazard ratio [HR] 3.45; 95% confidence interval [CI] 1.99 to 5.98; p <0.01), whereas no differences were observed between UAP or NSTEMI and SAP (HR 0.99; 95% CI 0.73 to 1.34; p = 0.94). In women with ACS, use of new-generation DES was associated with reduced risk of major adverse cardiac events (HR 0.58; 95% CI 0.34 to 0.98). The magnitude and direction of the effect with new-generation DES was uniform between women with or without ACS (pinteraction = 0.66). In conclusion, in women across the clinical spectrum of CAD, STEMI was associated with a greater risk of long-term mortality. Conversely, the adjusted risk of mortality between UAP or NSTEMI and SAP was similar. New-generation DESs provide improved long-term clinical outcomes irrespective of the clinical presentation in women.

  18. Multivariate Analysis of Long Term Variability in Icelandic Hydrological Series and its Relation to the Atmospheric Circulation in the North Atlantic

    NASA Astrophysics Data System (ADS)

    Jonsdottir, J. F.; Snorrason, A.; Jonsson, T.; Sveinsson, O. G.; Jonsson, P.

    2004-05-01

    Observed long-term variability in Icelandic time series of river flow is quite regular and significant. Similarly, aggregated long-term observations of glacial termini show significant changes since their initiation some 70 years ago. The relationship of these changes to variations in time series of climatic and oceanographic variables is quite important, since it can give indications of the possible relationship between hydrological time series and climate variability such as the Northern Atlantic pressure Oscillation (NAO). It can also give indications of the possible effects of anthropogenic climate changes due to increased concentration of greenhouse gases in the atmosphere. The variability of the atmospheric circulation in the North Atlantic has great effects on the precipitation and runoff in Iceland and in fact on the hydrology of the Nordic countries and the contries of western Europe. The island is situated in the middle of the North Atlantic Ocean in the path of the low-pressure frontal systems that transport moisture and thermal energy from the South to the North. A multivariate statistical analysis is performed on discharge data for several rivers in Iceland. The variability in the characteristics of the rivers is large since their watersheds are in various parts of the country, where glaciers and groundwater play a large role in the hydrology of some of the watersheds. The modes of variability are identified by a principal component analysis and the physical explanation of the modes is searched for by canonical correlation with data on precipitation, temperature, sea level pressure and other climatic and oceanographic variables. This study should give information on what processes relate the variability of the atmospheric circulation to the variability of the Icelandic rivers. It will thereby reveal the options of predicting the hydrological conditions in Iceland based on indices and information from the general prevalent circulation patterns. An

  19. Short and long term dispersion patterns of radionuclides in the atmosphere around the Fukushima Nuclear Power Plant.

    PubMed

    Leelossy, Adám; Mészáros, Róbert; Lagzi, István

    2011-12-01

    The Chernobyl accident and unfortunately the recent accident at the Fukushima 1 Nuclear Power Plant are the most serious accidents in the history of the nuclear technology and industry. Both of them have a huge and prolonged impact on environment as well as human health. Therefore, any technological developments and strategies that could diminish the consequences of such unfortunate events are undisputedly the most important issues of research. Numerical simulations of dispersion of radionuclides in the atmosphere after an accidental release can provide with a reliable prediction of the path of the plume. In this study we present a short (one month) and a long (11 years) term statistical study for the Fukushima 1 Nuclear Power Plant to estimate the most probable dispersion directions and plume structures of radionuclides on local scale using a Gaussian dispersion model. We analyzed the differences in plume directions and structures in case of typical weather/circulation pattern and provided a statistical-climatological method for a "first-guess" approximation of the dispersion of toxic substances. The results and the described method can support and used by decision makers in such important cases like the Fukushima accident. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. 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.

  1. 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.

  2. Long-term trends of continental-scale PCB patterns studied using a global atmosphere-ocean general circulation model.

    PubMed

    Stemmler, Irene; Lammel, Gerhard

    2012-07-01

    Continental-scale distribution and inter-continental transport of four polychlorinated biphenyl (PCB) congeners (28, 101, 153, 180) from 1950 to 2010 were studied using the global multicompartment chemistry transport model MPI-MCTM. Following identical primary emissions for all PCB congeners into air, most of the burden is stored in terrestrial (soil and vegetation) compartments. Thereby, PCB-28, PCB-101 and PCB-153 show a shift of the soil burden maxima from source to remote regions. This shift is downwind with regard to the westerlies for Eurasia and upwind for North America and more prominent for the lighter PCBs than for PCB-153 or PCB-180. In meridional direction, all congeners' distributions underwent a northward migration in Eurasia and North America since the 1950s. Inter-continental transport from Eurasian sources accounts largely for contamination of Alaska and British Columbia and determines the migration of the PCB distribution in soil in North America. Trans-Pacific transport occurs mainly in the gas phase in boreal winter (December-January-February) at 3-4 km altitude and is on a multi-year time scale strongly linked to the atmospheric pressure systems over the Pacific. Inter-continental transport of the lighter, more volatile PCBs is more efficient than for the heavier PCBs.

  3. Long-term changes in reflectivity and larger scale motions in the atmospheres of Jupiter and Saturn

    NASA Technical Reports Server (NTRS)

    Beebe, R. F.

    1986-01-01

    A multi-color, broad-band photographic program for monitoring atmospheric variability of Jupiter and Saturn with the 61-cm, f/75 telescope was continued. The archivial product consists of approximately 20 sequential images on 3 1/4 x 4 1/4 glass plates with a plate scale of 4.53 arc sec/mm. An eleven-step sensitometric wedge, recorded times of acquisition, and fiducial marks which determine the orientation of the plate, are recorded on each individual plate. This allows accurate positional measurements, as well as detailed relative surface brightness determinations. Detailed measurements of the Red Spot are being utilized in a study of zonal velocity variation and the ability to predict the longitude of the Red Spot during the Galileo mission. An ongoing 5-color series of Saturn has been maintained to map the seasonal changes in the belt-zone reflectivity. Digitization of a series of blue images containing the Red Spot and a series of red and blue images excluding the Red Spot are being processed and reduced to normalized surface brightness maps. This data is being utilized to map time-dependent brightness variations of selected features, belts, and ones.

  4. Preschool hyperactivity specifically elevates long-term mental health risks more strongly in males than females: a prospective longitudinal study through to young adulthood.

    PubMed

    Smith, Elizabeth; Meyer, Brenda J; Koerting, Johanna; Laver-Bradbury, Cathy; Lee, Louise; Jefferson, Harriet; Sayal, Kapil; Treglown, Luke; Thompson, Margaret; Sonuga-Barke, Edmund J S

    2017-01-01

    Evidence of continuities between preschool hyperactivity and adult mental health problems highlights the potential value of targeting early identification and intervention strategies. However, specific risk factors are currently unclear. This large-scale prospective longitudinal study aimed to identify which hyperactive preschoolers are at the greatest long-term risk of poor mental health. One hundred and seventy children (89 females) rated as hyperactive by their parents, and 88 non-hyperactive controls (48 females) were identified from a community sample of 4215 3-year-olds. Baseline data relating to behavioral/emotional problems and background characteristics were collected. Follow-up mental health and functional impairment outcomes were collected between 14 and 25 years of age. At age 3 years, males and females in the hyperactive group had similarly raised levels of hyperactivity and other behavior problems. In adolescence/young adulthood, these individuals showed elevated symptoms of ADHD, conduct disorder, mood disorder, anxiety and autism, as well as functional impairment. Preschool hyperactivity was strongly predictive of poor adolescent/adult outcomes for males across domains with effects being specifically driven by hyperactivity. For females, the effects of preschool hyperactivity were smaller and dropped to non-significant levels when other preschool problems were taken into account. Environmental risk factors also differed between the sexes, although these may also have been mediated by genetic risk. In conclusion, these results demonstrate marked sex differences in preschool predictors of later adolescent/adult mental health problems. Future research should include a measure of preschool inattention as well as hyperactivity. The findings highlight the potential value of tailored approaches to early identification strategies.

  5. Effect of long-term service exposure at elevated temperature on microstructural changes of 5Cr-0.5Mo steels

    NASA Astrophysics Data System (ADS)

    Das, S.; Joarder, A.

    1997-08-01

    Effects of long-term service exposure at elevated temperature on microstructural changes have been studied for both virgin and service-exposed process heater tube pipes of 5Cr-0.5Mo steels used in oil refineries. Samples selected for this study had experienced a nominal temperature range of 450 °C to 500 °C for about 20 to 25 years. Two different initial virgin microstructures were taken and designated by steel A and steel B. The virgin microstructure of steel A exhibited fine platelets of fibrous or hairlike M2C carbides within the ferrite grains and occasionally irregularly shaped M23C6, both along the grain boundaries and at the grain interiors, and very few spheroidally shaped M3C, either along the grain boundaries or at the grain interiors. The size, shape, position, distribution, and type of carbides in virgin steel A changed significantly due to 220,000 hours of service exposure in the temperature range of 450 °C to 500 °C. Massive M23C6 carbides precipitated along the grain boundaries. In addition, regular geometrically shaped M23C6 carbides, such as hexagonal, square, and triangular type, were observed to form at the grain interiors. The virgin steel B microstructure exhibited predominantly M23C6 carbides, either along the grain boundaries or at the lath boundaries. Occasionally, fine platelets of M2C carbides were also observed within the laths. The position, shape, distribution, and type of carbides did not change significantly due to 172,000 hours of service exposure in the temperature range of 450 °C to 500 °C. The average interparticle spacings of the carbides increased from 0.35 to 1.2 µm due to 172,000 hours of exposure.

  6. Long-term monitoring of atmospheric total gaseous mercury (TGM) at a remote site in Mt. Changbai area, northeastern China

    NASA Astrophysics Data System (ADS)

    Fu, X. W.; Feng, X.; Shang, L. H.; Wang, S. F.; Zhang, H.

    2012-02-01

    Total gaseous mercury (TGM) was continuously monitored at a remote site (CBS) in the Mt. Changbai area, northeastern China biennially from 24 October 2008 to 31 October 2010. The overall mean TGM concentration was 1.60 ± 0.51 ng m-3, which is lower than those reported from remote sites in eastern, southwestern and western China, indicating a relatively low regional anthropogenic mercury (Hg) emission intensity in northeastern China. Measurements at a site in the vicinity (~1.2 km) of the CBS station during August 2005 and July 2006 showed a significantly higher mean TGM concentration of 3.58 ± 1.78 ng m-3. The divergent result was partially attributed to fluctuations in the regional surface wind system and moreover an effect of local emission sources. The temporal variation of TGM at CBS was obviously influenced by regional sources as well as long-range transported Hg. Regional sources, frequently contributing to episodical high TGM concentrations, were pinpointed as a large iron mining district in northern North Korea and two large power plants and urban areas to the southwest of the sampling site. Source areas in Beijing, Tianjin, southern Liaoning, Hebei, northwestern Shanxi and northwestern Shandong were found to contribute to elevated TGM observations at CBS via long-range transport. The diurnal pattern of TGM at CBS was mainly regulated by regional sources, likely as well as intrusion of air masses from the free troposphere during summer season. There are no discernible seasonal pattern of TGM at CBS, which mainly showed links with the patterns of regional air movements and long-range transport.

  7. Relevance of long term time - Series of atmospheric parameters at a mountain observatory to models for climate change

    NASA Astrophysics Data System (ADS)

    Kancírová, M.; Kudela, K.; Erlykin, A. D.; Wolfendale, A. W.

    2016-10-01

    A detailed analysis has been made based on annual meteorological and cosmic ray data from the Lomnicky stit mountain observatory (LS, 2634 masl; 49.40°N, 20.22°E; vertical cut-off rigidity 3.85 GV), from the standpoint of looking for possible solar cycle (including cosmic ray) manifestations. A comparison of the mountain data with the Global average for the cloud cover in general shows no correlation but there is a possible small correlation for low clouds (LCC in the Global satellite data). However, whereas it cannot be claimed that cloud cover observed at Lomnicky stit (LSCC) can be used directly as a proxy for the Global LCC, its examination has value because it is an independent estimate of cloud cover and one that has a different altitude weighting to that adopted in the satellite-derived LCC. This statement is derived from satellite data (http://isccp.giss.nasa.gov/climanal7.html) which shows the time series for the period 1983-2010 for 9 cloud regimes. There is a significant correlation only between cosmic ray (CR) intensity (and sunspot number (SSN)) and the cloud cover of the types cirrus and stratus. This effect is mainly confined to the CR intensity minimum during the epoch around 1990, when the SSN was at its maximum. This fact, together with the present study of the correlation of LSCC with our measured CR intensity, shows that there is no firm evidence for a significant contribution of CR induced ionization to the local (or, indeed, Global) cloud cover. Pressure effects are the preferred cause of the cloud cover changes. A consequence is that there is no evidence favouring a contribution of CR to the Global Warming problem. Our analysis shows that the LS data are consistent with the Gas Laws for a stable mass of atmosphere.

  8. 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.

  9. 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

  10. 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

  11. Long-term chemical characterization of tropical and marine aerosols at the Cape Verde Atmospheric Observatory (CVAO) from 2007 to 2011

    NASA Astrophysics Data System (ADS)

    Fomba, K. W.; Müller, K.; van Pinxteren, D.; Poulain, L.; van Pinxteren, M.; Herrmann, H.

    2014-09-01

    The first long-term aerosol sampling and chemical characterization results from measurements at the Cape Verde Atmospheric Observatory (CVAO) on the island of São Vicente are presented and are discussed with respect to air mass origin and seasonal trends. In total 671 samples were collected using a high-volume PM10 sampler on quartz fiber filters from January 2007 to December 2011. The samples were analyzed for their aerosol chemical composition, including their ionic and organic constituents. Back trajectory analyses showed that the aerosol at CVAO was strongly influenced by emissions from Europe and Africa, with the latter often responsible for high mineral dust loading. Sea salt and mineral dust dominated the aerosol mass and made up in total about 80% of the aerosol mass. The 5-year PM10 mean was 47.1 ± 55.5 μg m-2, while the mineral dust and sea salt means were 27.9 ± 48.7 and 11.1 ± 5.5 μg m-2, respectively. Non-sea-salt (nss) sulfate made up 62% of the total sulfate and originated from both long-range transport from Africa or Europe and marine sources. Strong seasonal variation was observed for the aerosol components. While nitrate showed no clear seasonal variation with an annual mean of 1.1 ± 0.6 μg m-3, the aerosol mass, OC (organic carbon) and EC (elemental carbon), showed strong winter maxima due to strong influence of African air mass inflow. Additionally during summer, elevated concentrations of OM were observed originating from marine emissions. A summer maximum was observed for non-sea-salt sulfate and was connected to periods when air mass inflow was predominantly of marine origin, indicating that marine biogenic emissions were a significant source. Ammonium showed a distinct maximum in spring and coincided with ocean surface water chlorophyll a concentrations. Good correlations were also observed between nss-sulfate and oxalate during the summer and winter seasons, indicating a likely photochemical in-cloud processing of the marine and

  12. Effects of long-term (10 years) exposure to elevated CO2 and O3 on trembling Aspen carbon and nitrogen metabolism at the aspen FACE (Free-Air Carbon Dioxide Enrichment) study site [Abstract

    Treesearch

    R. Minocha; S. Long; S. Minocha; P Marquardt; M. Kubiske

    2010-01-01

    The objective of the present study was to evaluate the long-term (10 years) effects of elevated CO2 and O3 on the carbon and nitrogen metabolism of aspen trees. The study was conducted at the Aspen Free-Air Carbon Dioxide Enrichment (FACE) experimental site, Rhinelander, WI, (USA).

  13. Possible use of EPDM in radioactive waste disposal: Long term low dose rate and short term high dose rate irradiation in aquatic and atmospheric environment

    NASA Astrophysics Data System (ADS)

    Hacıoğlu, Fırat; Özdemir, Tonguç; Çavdar, Seda; Usanmaz, Ali

    2013-02-01

    In this study, changes in the properties of ethylene propylene diene terpolymer (EPDM) irradiated with different dose rates in ambient atmosphere and aqueous environment were investigated. Irradiations were carried out both with low dose and high dose rate irradiation sources. EPDM samples which were differentiated from each other by peroxide type and 5-ethylidene 2-norbornene (ENB) contents were used. Long term low dose rate irradiations were carried out for the duration of up to 2.5 years (total dose of 1178 kGy) in two different irradiation environments. Dose rates (both high and low), irradiation environments (in aquatic and open to atmosphere), and peroxide types (aliphatic or aromatic) were the parameters studied. Characterization of irradiated EPDM samples were performed by hardness, compression, tensile, dynamic mechanical analysis (DMA), TGA-FTIR, ATR-FTIR, XRD and SEM tests. It was observed that the irradiation in water environment led to a lower degree of degradation when compared to that of irradiation open to atmosphere for the same irradiation dose. In addition, irradiation environment, peroxide type and dose rate had effects on the extent of change in the properties of EPDM. It was observed that EPDM is relatively radiation resistant and a candidate polymer for usage in radioactive waste management.

  14. Long-term aerosol-mediated changes in cloud radiative forcing of deep clouds at the top and bottom of the atmosphere over the Southern Great Plains

    NASA Astrophysics Data System (ADS)

    Yan, Hongru; Li, Zhanqing; Huang, Jianping; Cribb, Maureen; Liu, Jianjun

    2014-07-01

    Aerosols can alter the macro- and micro-physical properties of deep convective clouds (DCCs) and their radiative forcing (CRF). This study presents what is arguably the first long-term estimate of the aerosol-mediated changes in CRF (AMCRF) for deep cloud systems derived from decade-long continuous ground-based and satellite observations, model simulations, and reanalysis data. Measurements were made at the US Department of Energy's Atmospheric Radiation Measurement Program's Southern Great Plains (SGP) site. Satellite retrievals are from the Geostationary Operational Environmental Satellite. Increases in aerosol loading were accompanied by the thickening of DCC cores and the expansion and thinning of anvils, due presumably to the aerosol invigoration effect (AIV) and the aerosol microphysical effect. Meteorological variables dictating these cloud processes were investigated. Consistent with previous findings, the AIV is most significant when the atmosphere is moist and unstable with weak wind shear. Such aerosol-mediated systematic changes in DCC core thickness and anvil size alter CRF at the top of atmosphere (TOA) and at the surface. Using extensive observations, ~300 DCC systems were identified over a 10 years period at the SGP site (2000-2011) and analyzed. Daily mean AMCRF at the TOA and at the surface are 29.3 W m-2 and 22.2 W m-2, respectively. This net warming effect due to changes in DCC microphysics offsets the cooling resulting from the first aerosol indirect effect.

  15. Long-term aerosol-mediated changes in cloud radiative forcing of deep clouds at the top and bottom of the atmosphere over the Southern Great Plains

    NASA Astrophysics Data System (ADS)

    Yan, Hongru; Li, Zhanqing; Huang, Jianping; Cribb, Maureen; Liu, Jianjun

    2014-02-01

    Aerosols can alter the macro- and micro-physical properties of deep convective clouds (DCC) and their radiative forcing (CRF). This study presents what is arguably the first long-term estimate of the aerosol-mediated changes in CRF (AMCRF) for deep cloud systems derived from decade-long continuous ground-based and satellite observations, model simulations and reanalysis data. Measurements were made at the US Department of Energy's Atmospheric Radiation Measurement Program's Southern Great Plains (SGP) site. Satellite retrievals are from the Geostationary Operational Environmental Satellite (GOES). Increases in aerosol loading were accompanied by the thickening of DCC cores and the expansion and thinning of anvils, due presumably to the aerosol invigoration effect (AIV) and the aerosol microphysical effect (AME). Meteorological variables dictating these cloud processes were investigated. Consistent with previous findings, the AIV is most significant when the atmosphere is moist and unstable with weak wind shear. Such aerosol-mediated systematic changes in DCC core thickness and anvil size alter CRF at the top of atmosphere (TOA) and at the surface. Using extensive observations, ~300 DCC systems were identified over a 10 yr period at the SGP site (2000-2011) and analyzed. Daily mean AMCRF at the TOA and at the surface are 29.3 W m-2 and 22.2 W m-2, respectively. This net warming effect due to changes in DCC microphysics offsets the cooling resulting from the first aerosol indirect effect.

  16. 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

  17. 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).

  18. 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

  19. 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

  20. 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.

  1. Persistent organic pollutants (POPs) in the atmosphere of coastal areas of the Ross Sea, Antarctica: Indications for long-term downward trends.

    PubMed

    Pozo, Karla; Martellini, Tania; Corsolini, Simonetta; Harner, Tom; Estellano, Victor; Kukučka, Petr; Mulder, Marie D; Lammel, Gerhard; Cincinelli, Alessandra

    2017-07-01

    Passive air samplers were used to evaluate long-term trends and spatial distribution of trace organic compounds in Antarctica. Duplicate PUF disk samplers were deployed at six automatic weather stations in the coastal area of the Ross sea (East Antarctica), between December 2010 and January 2011, during the XXVI Italian Scientific Research Expedition. Among the investigated persistent organic compounds, Hexachlorobenzene was the most abundant, with air concentrations ranging from 0.8 to 50 pg m(-3). In general, the following decreasing concentration order was found for the air samples analyzed: HCB > PeCB > PCBs > DDTs > HCHs. While HCB concentrations were in the same range as those reported in the atmosphere of other Antarctic sampling areas and did not show a decline, HCHs and DDTs levels were lower or similar to those determined one or two decades ago. In general, the very low concentrations reflected the pristine state of the East Antarctica air. Backward trajectories indicated the prevalence of air masses coming from the Antarctic continent. Local contamination and volatilization from ice were suggested as potential sources for the presence of persistent organic pollutants in the atmosphere. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Long-term increases in soil carbon due to ecosystem fertilization by atmospheric nitrogen deposition demonstrated by regional-scale modelling and observations.

    PubMed

    Tipping, E; Davies, J A C; Henrys, P A; Kirk, G J D; Lilly, A; Dragosits, U; Carnell, E J; Dore, A J; Sutton, M A; Tomlinson, S J

    2017-05-15

    Fertilization of nitrogen (N)-limited ecosystems by anthropogenic atmospheric nitrogen deposition (Ndep) may promote CO2 removal from the atmosphere, thereby buffering human effects on global radiative forcing. We used the biogeochemical ecosystem model N14CP, which considers interactions among C (carbon), N and P (phosphorus), driven by a new reconstruction of historical Ndep, to assess the responses of soil organic carbon (SOC) stocks in British semi-natural landscapes to anthropogenic change. We calculate that increased net primary production due to Ndep has enhanced detrital inputs of C to soils, causing an average increase of 1.2 kgCm(-2) (c. 10%) in soil SOC over the period 1750-2010. The simulation results are consistent with observed changes in topsoil SOC concentration in the late 20(th) Century, derived from sample-resample measurements at nearly 2000 field sites. More than half (57%) of the additional topsoil SOC is predicted to have a short turnover time (c. 20 years), and will therefore be sensitive to future changes in Ndep. The results are the first to validate model predictions of Ndep effects against observations of SOC at a regional field scale. They demonstrate the importance of long-term macronutrient interactions and the transitory nature of soil responses in the terrestrial C cycle.

  3. 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…

  4. Effects of long-term pH elevation on the sulfate-reducing and methanogenic activities of anaerobic sewer biofilms.

    PubMed

    Gutierrez, Oriol; Park, Donghee; Sharma, Keshab Raj; Yuan, Zhiguo

    2009-05-01

    The dosage of alkali is often applied by the wastewater industry to reduce the transfer of hydrogen sulfide from wastewater to the sewer atmosphere. In this paper the activities of Sulfate Reducing Bacteria (SRB) and Methanogenic Archaea (MA) under elevated pH conditions (8.6 and 9.0) were evaluated in a laboratory scale anaerobic sewer reactor. Compared to those in a control reactor without pH control (pH 7.6+/-0.1), the SRB activity was reduced by 30% and 50%, respectively, at pH 8.6 and pH 9.0. When normal pH was resumed, it took approximately 1 month for the SRB activity to fully recover. Methanogenic activities developed in the control reactor in 3 months after the reactor start-up, while no significant methanogenic activities were detected in the experimental reactor until normal pH was resumed. The results suggest that elevated pH at 8.6-9.0 suppressed the growth of methanogens. These experimental results clearly showed that, in addition to its well-known effect of reducing H(2)S transfer from the liquid to the gas phase, pH elevation considerably reduces sulfide and methane production by anaerobic sewer biofilms. These findings are significant for the optimal use of alkali addition to sewers for the control of H(2)S and CH(4) emissions. A model-based study showed that, by adding the alkali at the beginning rather than towards the end of a rising main, substantial savings in chemicals can be achieved while achieving the same level of sulfide emission control, and complete methane emission control.

  5. 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

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

    PubMed

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

    2015-01-01

    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. 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. 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.

  7. 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

  8. Long-term temperature variations in the stratosphere and troposphere caused by changes in gas and aerosol composition of the atmosphere

    NASA Astrophysics Data System (ADS)

    Dyominov, I.; Zadorozhny, A.

    A numerical 2-D zonally averaged interactive dynamical radiative-photochemical model of the troposphere and stratosphere including aerosol physics is used for investigation of long-term temperature changes caused by anthropogenic pollution of the atmosphere by CO2 , CH4, N2O, CFCs, HCFCs, HFCs, CH 3CCl 3 and CCl4 as well as by discharges to the atmosphere of sulphate species during the Pinatubo eruption. The model allows calculating self-consistently 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 (PSCs) of types I and II. The scenarios of expected changes of the anthropogenic pollutants for the period from 1990 through 2050 are taken from Climate Change 1995. The calculations of the long-term temperature variations due to anthropogenic emission s show that the greatest temperature changes are observed in the Southern Hemisphere in winter/spring periods. For example, the temperature changes at a height of 40 km at 45°S in December 2050 are about -4.85 K, 0.89 K, -2.21 K, and -4.32 K respectively for anthropogenic discharges of CO2, CH4, N2O, and chlorine species. The changes in the Northern Hemisphere are smaller. They are equal to about -4.5 K, 0.68 K, -1.46 K, and -3.17 K at 45°N. The temperature changes in the stratosphere are caused by the corresponding ozone variations and temperature feedbacks. In the troposphere, the temperature changes are determined by the greenhouse effect caused by optically active pollutants. For example, temperature increases near the Earth's surface at 45 °N in December of 2050 due to anthropogenic discharges of CO2, CH4, N2O, and chlorine species are about 0.87 K, 0.19 K, 0.14 K, and 0.32 K, respectively. The calculations show that short -term megaton discharges of sulphate species to the atmosphere during the Pinatubo eruption led to significant long-term

  9. Long Term Prognosis

    MedlinePlus

    ... TERM PROGNOSIS The long-term outlook of pediatric cardiomyopathy continues to be unpredictable because it occurs with ... a child also depends on the type of cardiomyopathy and the stage the disease is first diagnosed. ...

  10. 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, L.; McDermott, F. P.; Werner, M.

    2016-12-01

    The control exerted by large scale atmospheric circulation modes (such as the North Atlantic Oscillation) 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 are underpinned by assumptions about a long-term stationarity of the influence of the atmospheric pattern of interest on δ18Op. However, here we identify regional temporal non-stationarities in the δ18Op-NAO relationship during the instrumental period using both observations (GNIP) and the output of an isotope-enabled general circulation model (ECHAM5-wiso). Our results show that the polarity of the East Atlantic (EA) pattern affects the strength of the δ18Op-NAO relationship in some European locations. These non-stationarities 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. This means 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. We identify regions within Europe where temporal changes in the NAO, air temperature and precipitation can be more robustly reconstructed using δ18O time series from natural archives. Identification of such regions is crucial so that resources can be focused into the areas least affected by such non-stationarities.

  11. 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.

  12. [Early invasive strategy no better than a selective invasive strategy for patients with non-ST-segment elevation acute coronary syndromes and elevated cardiac troponin T levels: long-term follow-up results of the ICTUS trial].

    PubMed

    Windhausen, F; Hirsch, A; Tijssen, J G P; Verheugt, F W A; Cornel, J H; de Winter, R J

    2008-02-23

    To determine whether routine coronary angiography followed by revascularisation where appropriate is better than initial drug treatment in patients with non-ST-segment elevation acute coronary syndromes (nSTE-ACS) and elevated troponin T concentrations. Multicentre randomised clinical trial (www.controlled-trials. com, number: SRCTN82153174). Patients with nSTE-ACS and elevated cardiac troponin were randomly assigned to an early invasive strategy or a selective invasive strategy. The early invasive strategy consisted of coronary angiography and revascularisation as indicated within 48 hours. The selective invasive strategy consisted of initial drug therapy; catheterisation was performed if the patient developed refractory angina or recurrent ischaemia. The main endpoints were a composite of death, recurrent myocardial infarction and rehospitalisation for anginal symptoms within 3 years, and all-cause mortality within 4 years. A total of 1200 patients were enrolled from 42 hospitals in the Netherlands. The in-hospital revascularisation rate was 76% in the early invasive group and 40% in the selective invasive group. After 3 years, the cumulative rate for the composite endpoint was 30.0% in the early invasive group and 26.0% in the selective invasive group (hazard ratio 1.21; 95% CI: 0.97-1.50; p = 0.09). The 4-year all-cause mortality rate was similar in both treatment groups (7.9% vs 7.7%; p = 0.62). Long-term follow-up of this trial suggests that an early invasive strategy is not better than a selective invasive strategy in patients with nSTE-ACS and elevated cardiac troponin. Therefore, implementation of either strategy is acceptable in these patients.

  13. A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

    PubMed

    Pannatier, Elisabeth Graf; Thimonier, Anne; Schmitt, Maria; Walthert, Lorenz; Waldner, Peter

    2011-03-01

    Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

  14. Long-term trend in ground-based air temperature and its responses to atmospheric circulation and anthropogenic activity in the Yangtze River Delta, China

    NASA Astrophysics Data System (ADS)

    Peng, Xia; She, Qiannan; Long, Lingbo; Liu, Min; Xu, Qian; Zhang, Jiaxin; Xiang, Weining

    2017-10-01

    The Yangtze River Delta (YRD), including Shanghai City, Jiangsu and Zhejiang Provinces, is the largest metropolitan region in China. In the past decades, the region has experienced massive urbanization and detrimentally affected the environment in the region. Identifying the spatio-temporal variations of climate change and its influencing mechanism in the YRD is an important task for assessing their impacts on the local society and ecosystem. Based on long-term (1958-2014) observation data of meteorological stations, three temperature indices, i.e. extreme maximum temperature (TXx), extreme minimum temperature (TNn), and mean temperature (TMm), were selected and spatialized with climatological calculations and spatial techniques. Evolution and spatial heterogeneity of three temperature indices over YRD as well as their links to atmospheric circulation and anthropogenic activity were investigated. In the whole YRD, a statistically significant overall uptrend could be detected in three temperature indices with the Mann-Kendall (M-K) trend test method. The linear increasing trend for TMm was 0.31 °C/10 a, which was higher than the global average (0.12 °C/10 a during 1951-2012). For TXx and TNn, the increasing rates were 0.41 °C/10 a and 0.52 °C/10 a. Partial correlation analysis indicated that TMm was more related with TXx (rp = 0.68, p < 0.001) than TNn (rp = 0.48, p < 0.001). Furthermore, it was detected with M-K analysis at pixel scale that 62.17%, 96.75% and 97.05% of the areas in the YRD showed significant increasing trends for TXx, TNn and TMm, respectively. The increasing trend was more obvious in the southern mountainous areas than the northern plains areas. Further analysis indicated that the variation of TXx over YRD was mainly influenced by anthropogenic activities (e.g. economic development), while TNn was more affected by atmospheric circulations (e.g., the Eurasian zonal circulation index (EAZ) and the cold air activity index (CA)). For TMm, it was a

  15. Modelling of the long-term fate of pesticide residues in agricultural soils and their surface exchange with the atmosphere: Part II. Projected long-term fate of pesticide residues.

    PubMed

    Scholtz, M T; Bidleman, T F

    2007-05-01

    In the first part of this paper, a simple coupled dynamic soil-atmosphere model for studying the gaseous exchange of pesticide soil residues with the atmosphere is described and evaluated by comparing model results with published measurements of pesticide concentrations in air and soil. In Part II, the model is used to study the concentration profiles of pesticide residues in both undisturbed and annually tilled agricultural soils. Future trends are estimated for the measured air and soil concentrations of lindane and six highly persistent pesticides (toxaphene, p,p'-DDE, dieldrin, cis- and trans-chlordane and trans-nonachlor) over a twenty-year period due to volatilization and leaching into the deeper soil. Wet deposition and particle associated pesticide deposition (that increase soil residue concentrations) and soil erosion, degradation in the soil (other than for lindane) and run-off in precipitation are not considered in this study. Estimates of the rain deposition fluxes are reported that show that, other than for lindane, net volatilization fluxes greatly exceed rain deposition fluxes. The model shows that the persistent pesticides studied are highly immobile in soil and that loss of these highly persistent residues from the soil is by volatilization rather than leaching into the deeper soil. The soil residue levels of these six pesticides are currently sources of net volatilization to the atmosphere and will remain so for many years. The maximum rate of volatilization from the soil was simulated by setting the atmospheric background concentration to zero; these simulations show that the rates of volatilization will not be significantly increased since soil resistance rather than the atmospheric concentration controls the volatilization rates. Annual tilling of the soils increases the volatilization loss to the atmosphere. Nonetheless, the model predicts that, if only air-soil exchange is considered, more than 76% of current persistent pesticide residues

  16. 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

  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. 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.

  19. Long-term trends (1990-2014), health risks, and sources of atmospheric polycyclic aromatic hydrocarbons (PAHs) in the U.S.

    PubMed

    Liu, Bian; Xue, Zhuqing; Zhu, Xianlei; Jia, Chunrong

    2017-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are a category of over 100 various chemicals released from numerous combustion sources. The ubiquity and toxicity of PAHs have posed high health risks on human populations. This study aims to examine the long-term trends of atmospheric PAHs at the national-level in the U.S., and evaluate their cancer risks. Daily concentrations of PAHs measured at 169 monitoring stations between 1990 and 2014 were obtained from the U.S. Environmental Protection Agency's Air Quality System. Temporal trends were examined using generalized linear model with generalized estimating equations. Random-effects analysis of variance was performed to explore variance between regions, sites, years, and months with a hierarchical structure. Source categories were identified using diagnostic ratios. National population level cancer risks were estimated using the relative potency factors and inhalation unit risk method. Ambient PAH concentrations displayed an overall downward trend (6-9% annual reduction) in urban areas, but not in rural areas. Seasonal and weekday/weekend effects were significant. Urban concentrations were twice of the rural level. The between-site variation outweighed the temporal variation, indicating large spatial heterogeneity. The predominant PAH sources were from traffic and non-traffic related fuel combustions with a dominant contribution from diesel emissions. The average excess lifetime cancer risk was estimated to be 9.3 ± 30.1 × 10(-6) (GM: 4.2 × 10(-6)) from exposure to ten carcinogenic PAHs. This is the first comprehensive study of the spatiotemporal trends of ambient PAHs at the U.S. national level. The results indicate that future efforts aimed to reduce PAH exposures should focus on diesel emission controls and extending the geographic coverage of air monitoring. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. The effect of long-term atmospheric CO2 enrichment on the intrinsic water-use efficiency of sour orange trees.

    PubMed

    Leavitt, S W; Idso, S B; Kimball, B A; Burns, J M; Sinha, A; Stott, L

    2003-01-01

    Every two months of 1992, as well as on three occasions in 1994-1995, we obtained leaf samples together with samples of surrounding air from eight well-watered and fertilized sour orange (Citrus aurantium L.) trees that were growing out-of-doors at Phoenix, Arizona, USA. These trees had been planted in the ground as small seedlings in July of 1987 and enclosed in pairs by four clear-plastic-wall open-top chambers of which two have been continuously maintained since November of that year at a CO2 concentration of 400 micromol mol(-1) and two have been maintained at 700 micromol mol(-1). In September 2000, we also extracted north-south and east-west oriented wood cores that passed through the center of each tree's trunk at a height of 45 cm above the ground. Stable-carbon isotope ratios (13C/12C) derived from these leaf, wood and air samples were used to evaluate each tree's intrinsic water-use efficiency (iWUE). The grand-average result was an 80% increase in this important plant parameter in response to the 300 micromol mol(-1) increase in atmospheric CO2 concentration employed in the study. This increase in sour orange tree iWUE is identical to the long-term CO2-induced increase in the trees' production of wood and fruit biomass, which suggests there could be little to no change in total water-use per unit land area for this species as the air's CO2 content continues to rise. It is also identical to the increase in the mean iWUE reported for 23 groups of naturally occurring trees scattered across western North America that was caused by the historical rise in the air's CO2 content that occurred between 1800 and 1985.

  1. Changes of gill and hemocyte-related bio-indicators during long term maintenance of the vent mussel Bathymodiolus azoricus held in aquaria at atmospheric pressure.

    PubMed

    Bettencourt, Raul; Dando, Paul; Rosa, Domitília; Riou, Virginie; Colaço, Ana; Sarrazin, Jozée; Sarradin, Pierre-Marie; Santos, Ricardo Serrão

    2008-05-01

    The deep-sea hydrothermal vent mussel Bathymodiolus azoricus has been the subject of several studies aimed at understanding the physiological adaptations that vent animals have developed in order to cope with the particular physical and chemical conditions of hydrothermal environments. In spite of reports describing successful procedures to maintain vent mussels under laboratory conditions at atmospheric pressure, few studies have described the mussel's physiological state after a long period in aquaria. In the present study, we investigate changes in mucocytes and hemocytes in B. azoricus over the course of several months after deep-sea retrieval. The visualization of granules of mucopolysaccharide or glycoprotein was made possible through their inherent auto-fluorescent property and the Alcian blue-Periodic Acid Schiff staining method. The density and distribution of droplets of mucus-like granules was observed at the ventral end of lamellae during acclimatization period. The mucus-like granules were greatly reduced after 3 months and nearly absent after 6 months of aquarium conditions. Additionally, we examined the depletion of endosymbiont bacteria from gill tissues, which typically occurs within a few weeks in sea water under laboratory conditions. The physiological state of B. azoricus after 6 months of acclimatization was also examined by means of phagocytosis assays using hemocytes. Hemocytes from mussels held in aquaria up to 6 months were still capable of phagocytosis but to a lesser extent when compared to the number of ingested yeast particles per phagocytic hemocytes from freshly collected vent mussels. We suggest that the changes in gill mucopolysaccharides and hemocyte glycoproteins, the endosymbiont abundance in gill tissues and phagocytosis are useful health criteria to assess long term maintenance of B. azoricus in aquaria. Furthermore, the laboratory set up to which vent mussels were acclimatized is an applicable system to study physiological

  2. Long-term outcome after an early invasive versus selective invasive treatment strategy in patients with non-ST-elevation acute coronary syndrome and elevated cardiac troponin T (the ICTUS trial): a follow-up study.

    PubMed

    Hirsch, Alexander; Windhausen, Fons; Tijssen, Jan G P; Verheugt, Freek W A; Cornel, Jan Hein; de Winter, Robbert J

    2007-03-10

    The ICTUS trial was a study that compared an early invasive with a selective invasive treatment strategy in patients with non-ST-elevation acute coronary syndrome (nSTE-ACS). The study reported no difference between the strategies for frequency of death, myocardial infarction, or rehospitalisation after 1 year. We did a follow-up study to assess the effects of these treatment strategies after 4 years. 1200 patients with nSTE-ACS and an elevated cardiac troponin were enrolled from 42 hospitals in the Netherlands. Patients were randomly assigned either to an early invasive strategy, including early routine catheterisation and revascularisation where appropriate, or to a more selective invasive strategy, where catheterisation was done if the patient had refractory angina or recurrent ischaemia. The main endpoints for the current follow-up study were death, recurrent myocardial infarction, or rehospitalisation for anginal symptoms within 3 years after randomisation, and cardiovascular mortality and all-cause mortality within 4 years. Analysis was by intention-to-treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN82153174. The in-hospital revascularisation rate was 76% in the early invasive group and 40% in the selective invasive group. After 3 years, the cumulative rate for the combined endpoint was 30.0% in the early invasive group compared with 26.0% in the selective invasive group (hazard ratio 1.21; 95% CI 0.97-1.50; p=0.09). Myocardial infarction was more frequent in the early invasive strategy group (106 [18.3%] vs 69 [12.3%]; HR 1.61; 1.19-2.18; p=0.002). Rates of death or spontaneous myocardial infarction were not different (76 [14.3%] patients in the early invasive and 63 [11.2%] patients in the selective invasive strategy [HR 1.19; 0.86-1.67; p=0.30]). No difference in all-cause mortality (7.9%vs 7.7%; p=0.62) or cardiovascular mortality (4.5%vs 5.0%; p=0.97) was seen within 4 years. Long-term follow-up of

  3. Long-term effects of elevated carbon dioxide concentration and provenance on four clones of Sitka spruce (Picea sitchensis). II. Photosynthetic capacity and nitrogen use efficiency.

    PubMed

    Centritto; Jarvis

    1999-10-01

    Four clones of Sitka spruce (Picea sitchensis (Bong.) Carr.) from two provenances, at 53.2 degrees N (Skidegate a and Skidegate b) and at 41.3 degrees N (North Bend a and North Bend b), were grown for three growing seasons in ambient (~350 micromol per mol) and elevated (~700 micromol per mol) CO2 concentrations. The clones were grown in stress-free conditions (adequate nutrition and water) to assess the effect of elevated [CO2] on tree physiology. Growth in elevated [CO2] significantly increased instantaneous photosynthetic rates of the clonal Sitka spruce saplings by about 62%. Downward acclimation of photosynthesis (A) was found in all four clones grown in elevated [CO2]. Rubisco activity and total chlorophyll concentration were also significantly reduced in elevated [CO2]. Provenance did not influence photosynthetic capacity. Best-fit estimates of Jmax (maximum rate of electron transport), Vcmax (RuBP-saturated rate of Rubisco) and Amax (maximum rate of assimilation) were derived from responses of A to intercellular [CO2] by using the model of Farquhar et al. (1980). At any leaf N concentration, the photosynthetic parameters were reduced by growth in elevated [CO2]. However, the ratio between Jmax and Vcmax was unaffected by CO2 growth concentration, indicating a tight coordination in the allocation of N between thylakoid and soluble proteins. In elevated [CO2], the more southerly clones had a higher initial N use efficiency (more carbon assimilated per unit of leaf N) than the more northerly clones, so that they had more N available for those processes or organs that were most limiting to growth at a particular time. This may explain the initial higher growth stimulation by elevated [CO2] in the North Bend clones than in the Skidegate clones.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    Scott, Russell; Biederman, Joel

    2017-04-01

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

  6. Growth and metal removal potential of a Phormidium bigranulatum-dominated mat following long-term exposure to elevated levels of copper.

    PubMed

    Kumar, Dhananjay; Gaur, J P

    2014-09-01

    The present study explores the tolerance and metal removal response of a well-developed 2-week-old Phormidium mat after long-term exposure to Cu(2+)-enriched medium. Cu(2+) enrichment inhibited increase in mat biomass in a concentration-dependent manner. Mat area and the number of entrapped air bubbles decreased as Cu(2+) concentration increased in the medium. Decrease in number of air bubbles obviously reflects the adverse effect of Cu(2+) on photosynthetic performance of the mat. Metal enrichment did not substantially alter the amount of pigments, such as chlorophyll a, chlorophyll b, carotenoids, and phycocyanin, in the mat. Enhancement of Cu(2+) concentration in the medium led to changes in species composition of the test mat; however, Phormidium bigranulatum always remained the dominant organism. Relative share of green algae and some cyanobacterial taxa, namely, Lyngbya sp. and Oscillatoria tenuis, in the mat were increased by Cu(2+) enrichment. The mat successfully removed 80 to 94 % Cu(2+) from the growth medium containing 10 to 100 μM Cu(2+). Extracellular polysaccharides, whose share increased in the mat community after metal addition, seem to have contributed substantially to metal binding by the mat biomass.

  7. Response of photosynthesis in second-generation Pinus radiata trees to long-term exposure to elevated carbon dioxide partial pressure.

    PubMed

    Greenep, H; Turnbull, M H; Whitehead, D

    2003-06-01

    Second-generation Pinus radiata D. Don trees, propagated from cuttings of 4-year-old trees previously grown at ambient (36 Pa) and elevated (65 Pa) CO2 partial pressure (Ca) were grown under the same conditions in open-top chambers for a further year. As cuttings of the original trees, these second-generation trees were physiologically the same age as the first-generation trees with the only difference between the two being size. This allowed us to test the effects of tree size independently of age or duration of exposure. Total non-structural carbohydrate concentration, area-based nitrogen concentration, leaf mass per unit area and chlorophyll concentration measured in three foliage age cohorts were unaffected by either age or Ca. There were no signs of photosynthetic down-regulation in trees grown at elevated Ca. When measured at the growth Ca, photosynthetic rate in young needles during summer, autumn and spring was 34, 43 and 38% higher, respectively, in trees grown at elevated Ca than in trees grown at ambient Ca. In older needles, the corresponding photosythetic rate increases were 26, 47 and 49%. Water-use efficiency, determined by stable carbon isotope analysis, was 49% higher in foliage in the elevated Ca treatment than in foliage in the ambient Ca treatment. This increase was entirely due to photosynthetic enhancement, because stomatal conductance did not differ between treatments. We conclude that down-regulation of photosynthesis at elevated Ca is related to tree size rather than tree age or duration of exposure, and that enhanced photosynthetic rates can be maintained while sink strength is high enough to use the excess photosynthates.elevated CO2, needle age, photosynthetic down-regulation, photosynthetic enhancement, sink strength, water-use efficiency.

  8. Reduced volume and increased training intensity elevate muscle Na+-K+ pump alpha2-subunit expression as well as short- and long-term work capacity in humans.

    PubMed

    Bangsbo, Jens; Gunnarsson, Thomas P; Wendell, Jesper; Nybo, Lars; Thomassen, Martin

    2009-12-01

    The present study examined muscle adaptations and alterations in work capacity in endurance-trained runners as a result of a reduced amount of training combined with speed endurance training. For a 6- to 9-wk period, 17 runners were assigned to either a speed endurance group with a 25% reduction in the amount of training but including speed endurance training consisting of six to twelve 30-s sprint runs 3-4 times/wk (SET group n = 12) or a control group (n = 5), which continued the endurance training ( approximately 55 km/wk). For the SET group, the expression of the muscle Na(+)-K(+) pump alpha(2)-subunit was 68% higher (P < 0.05) and the plasma K(+) level was reduced (P < 0.05) during repeated intense running after 9 wk. Performance in a 30-s sprint test and the first of the supramaximal exhaustive runs was improved (P < 0.05) by 7% and 36%, respectively, after the speed endurance training period. In the SET group, maximal O(2) uptake was unaltered, but the 3-km (3,000-m) time was reduced (P < 0.05) from 10.4 +/- 0.1 to 10.1 +/- 0.1 min and the 10-km (10,000-m) time was improved from 37.3 +/- 0.4 to 36.3 +/- 0.4 min (means +/- SE). Muscle protein expression and performance remained unaltered in the control group. The present data suggest that both short- and long-term exercise performances can be improved with a reduction in training volume if speed endurance training is performed and that the Na(+)-K(+) pump plays a role in the control of K(+) homeostasis and in the development of fatigue during repeated high-intensity exercise.

  9. 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.

  10. Short-term effects of fertilization on photosynthesis and leaf morphology of field-grown loblolly pine following long-term exposure to elevated CO2 concentration

    Treesearch

    Chris A. Maier; Sari Palmroth; Eric Ward

    2008-01-01

    We examined effects of a first nitrogen (N) fertilizer application on upper-canopy needle morphology and gas exchange in ~20-m-tall loblolly pine (Pinus taeda L.) exposed to elevated carbon dioxide concentration ([CO2]) for 9 years. Duke Forest free-air CO2 enrichment (FACE) plots were split and half of...

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

    PubMed

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

    2014-10-28

    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.

  12. 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.

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

    SciTech Connect

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

    2014-10-13

    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, in this study 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. Finally, our results have implications for how we manage native grasslands in the face of changing climate.

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

    DOE PAGES

    Zelikova, Tamara Jane; Blumenthal, Dana M.; Williams, David G.; ...

    2014-10-13

    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, in this study 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 andmore » 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. Finally, our results have implications for how we manage native grasslands in the face of changing climate.« less

  15. Long-term effects of elevated carbon dioxide concentration on sour orange wood specific gravity, modulus of elasticity, and microfibril angle

    Treesearch

    David Kretschmann; James Evans; Mike Wiemann; Bruce A. Kimball; Sherwood B. Idso

    2007-01-01

    The carbon dioxide (CO2) concentration of Earth’s atmosphere continues to rise. Plants in general are responsive to changing CO2 concentrations, which suggests changes in agricultural productivity in the United States and around the world. The ability of plants to absorb CO2 during photosynthesis and then store carbon in their structure or sequester it in the soil has...

  16. Growth-differentiation factor 15 for long-term prognostication in patients with non-ST-elevation acute coronary syndrome: an Invasive versus Conservative Treatment in Unstable coronary Syndromes (ICTUS) substudy.

    PubMed

    Damman, Peter; Kempf, Tibor; Windhausen, Fons; van Straalen, Jan P; Guba-Quint, Anja; Fischer, Johan; Tijssen, Jan G P; Wollert, Kai C; de Winter, Robbert J; Hirsch, Alexander

    2014-03-15

    No five-year long-term follow-up data is available regarding the prognostic value of GDF-15. Our aim is to evaluate the long-term prognostic value of admission growth-differentiation factor 15 (GDF-15) regarding death or myocardial infarction (MI) in patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). This is a subanalysis from the ICTUS (Invasive versus Conservative Treatment in Unstable coronary Syndromes) trial, including troponin positive NSTE-ACS patients. The main outcome for the current analysis was 5-year death or spontaneous MI. GDF-15 samples were available in 1151 patients. The prognostic value of GDF-15, categorized into <1200 ng/L, 1200-1800 ng/L and >1800 ng/L, was assessed in unadjusted and adjusted Cox regression models. Adjustments were made for identified univariable risk factors. The additional discriminative and reclassification value of GDF-15 beyond the independent risk factors was assessed by the category-free net reclassification improvement (1/2 NRI(>0)) and the integrated discrimination improvement (IDI) RESULTS: Compared to GDF-15<1200 ng/L, a GDF-15>1800 ng/L was associated with an increased hazard ratio for death or spontaneous MI, mainly driven by mortality. GDF-15 levels were predictive after adjustments for other identified predictors. Additional discriminative value was shown with the IDI, not with the NRI. In patients presenting with NSTE-ACS and elevated troponin T, GDF-15 provides prognostic information in addition to identified predictors for mortality and spontaneous MI and can be used to identify patients at high risk during long-term follow-up. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  17. 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.

  18. Usefulness of the admission electrocardiogram to predict long-term outcomes after non-ST-elevation acute coronary syndrome (from the FRISC II, ICTUS, and RITA-3 [FIR] Trials).

    PubMed

    Damman, Peter; Holmvang, Lene; Tijssen, Jan G P; Lagerqvist, Bo; Clayton, Tim C; Pocock, Stuart J; Windhausen, Fons; Hirsch, Alexander; Fox, Keith A A; Wallentin, Lars; de Winter, Robbert J

    2012-01-01

    The aim of this study was to evaluate the independent prognostic value of qualitative and quantitative admission electrocardiographic (ECG) analysis regarding long-term outcomes after non-ST-segment elevation acute coronary syndromes (NSTE-ACS). From the Fragmin and Fast Revascularization During Instability in Coronary Artery Disease (FRISC II), Invasive Versus Conservative Treatment in Unstable Coronary Syndromes (ICTUS), and Randomized Intervention Trial of Unstable Angina 3 (RITA-3) patient-pooled database, 5,420 patients with NSTE-ACS with qualitative ECG data, of whom 2,901 had quantitative data, were included in this analysis. The main outcome was 5-year cardiovascular death or myocardial infarction. Hazard ratios (HRs) were calculated with Cox regression models, and adjustments were made for established outcome predictors. The additional discriminative value was assessed with the category-less net reclassification improvement and integrated discrimination improvement indexes. In the 5,420 patients, the presence of ST-segment depression (≥1 mm; adjusted HR 1.43, 95% confidence interval [CI] 1.25 to 1.63) and left bundle branch block (adjusted HR 1.64, 95% CI 1.18 to 2.28) were independently associated with long-term cardiovascular death or myocardial infarction. Risk increases were short and long term. On quantitative ECG analysis, cumulative ST-segment depression (≥5 mm; adjusted HR 1.34, 95% CI 1.05 to 1.70), the presence of left bundle branch block (adjusted HR 2.15, 95% CI 1.36 to 3.40) or ≥6 leads with inverse T waves (adjusted HR 1.22, 95% CI 0.97 to 1.55) was independently associated with long-term outcomes. No interaction was observed with treatment strategy. No improvements in net reclassification improvement and integrated discrimination improvement were observed after the addition of quantitative characteristics to a model including qualitative characteristics. In conclusion, in the FRISC II, ICTUS, and RITA-3 NSTE-ACS patient-pooled data set

  19. 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.

  20. The elevated T-maze task as an animal model to simultaneously investigate the effects of drugs on long-term memory and anxiety in mice.

    PubMed

    Asth, Laila; Lobão-Soares, Bruno; André, Eunice; Soares, Vanessa de Paula; Gavioli, Elaine Cristina

    2012-04-10

    The elevated T-maze (ETM) is an apparatus derived from the elevated plus-maze test, which is used to evaluate anxiety. Because anxiety is a biasing factor in models of memory, this study proposed the ETM as a task for the simultaneous assessment of memory and anxiety in mice. The ETM consists of one enclosed and two open arms. The procedure is based on the avoidance of open spaces learned during training session, in which mice were exposed to the enclosed arm as many times as needed to stay 300s. In the test session, memory is assessed by re-exposing the mouse to the enclosed arm and the latency to enter an open arm was recorded. The anxiolytic diazepam (DZP; 1 or 2mg/kg) and the amnestic biperiden (BPR; 0.5, 1 or 3mg/kg) were injected at three distinct times: pre-training, post-training, and pre-test. Pre-training administration of BPR 1 and DZP 2 increased the number of trials needed to reach the avoidance criterion, suggesting a passive avoidance learning impairment. However, BPR induced hyperlocomotion, which could bias the interpretation of any BPR-induced effects during the training session. Pre-training injection of BPR did not affect the spontaneous increase in the latency to enter an open arm between trials, while DZP reduced latencies in the first three trials suggesting anxiolysis. In the test session, pre-training injection of BPR 1 and DZP 2 reduced latencies to enter an open arm, indicating memory impairment. Post-training and pre-test injection of DZP or BPR did not affect memory. In conclusion, the proposed ETM task is practical for the detection of the anxiolytic and amnesic effects of drugs.

  1. Warming Reduces Carbon Losses from Grassland Exposed to Elevated Atmospheric Carbon Dioxide

    PubMed Central

    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

  2. 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.

  3. Mortality benefit of long-term angiotensin-converting enzyme inhibitors or angiotensin receptor blockers after successful percutaneous coronary intervention in non-ST elevation acute myocardial infarction.

    PubMed

    González-Cambeiro, María Cristina; López-López, Andrea; Abu-Assi, Emad; Raposeiras-Roubín, Sergio; Peña-Gil, Carlos; García-Acuña, José; González-Juanatey, Ramón

    2016-12-01

    Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) have been shown to reduce mortality after myocardial infarction (MI). Current guidelines recommend their prescription in all patients after MI. Limited data are available on whether ACEIs/ARBs still improve prognosis in the contemporary era of non-ST elevation MI (NSTEMI) management. We aimed to evaluate the mortality benefit of ACEIs/ARBs in NSTEMI patients treated successfully with percutaneous coronary intervention (PCI). We analyzed 2784 patients with NSTEMI treated successfully with in-hospital PCI. Two groups were formed based on ACEI/ARB prescription at discharge. Two propensity score (PS) analyses were performed to control for differences in covariates: one with adjustment among the entire cohort, and the other with PS matching (n=1626). The outcome variable was all-cause mortality at four-year follow-up. There were 1902 (68.3%) patients prescribed ACEIs/ARBs at discharge. When adjusted by PS, ACEI/ARB use was associated with a hazard ratio (HR) for mortality of 0.75 (0.60-0.94; absolute risk reduction [ARR] 4.0%) in the whole cohort (p=0.01). After one-to-one PS matching (n=813 in each group), the mortality rate was significantly lower in patients prescribed ACEIs/ARBs, with HR of 0.77 (0.63-0.94; ARR 3.8%) (p=0.03). In this observational study of patients with NSTEMI, all of them treated successfully by PCI, the use of ACEIs/ARBs was significantly associated with a lower risk of four-year all-cause mortality. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  4. Plant diversity effects on soil food webs are stronger than those of elevated CO2 and N deposition in a long-term grassland experiment.

    PubMed

    Eisenhauer, Nico; Dobies, Tomasz; Cesarz, Simone; Hobbie, Sarah E; Meyer, Ross J; Worm, Kally; Reich, Peter B

    2013-04-23

    Recent metaanalyses suggest biodiversity loss affects the functioning of ecosystems to a similar extent as other global environmental change agents. However, the abundance and functioning of soil organisms have been hypothesized to be much less responsive to such changes, particularly in plant diversity, than aboveground variables, although tests of this hypothesis are extremely rare. We examined the responses of soil food webs (soil microorganisms, nematodes, microarthropods) to 13-y manipulation of multiple environmental factors that are changing at global scales--specifically plant species richness, atmospheric CO2, and N deposition--in a grassland experiment in Minnesota. Plant diversity was a strong driver of the structure and functioning of soil food webs through several bottom-up (resource control) effects, whereas CO2 and N only had modest effects. We found few interactions between plant diversity and CO2 and N, likely because of weak interactive effects of those factors on resource availability (e.g., root biomass). Plant diversity effects likely were large because high plant diversity promoted the accumulation of soil organic matter in the site's sandy, organic matter-poor soils. Plant diversity effects were not explained by the presence of certain plant functional groups. Our results underline the prime importance of plant diversity loss cascading to soil food webs (density and diversity of soil organisms) and functions. Because the present results suggest prevailing plant diversity effects and few interactions with other global change drivers, protecting plant diversity may be of high priority to maintain the biodiversity and functioning of soils in a changing world.

  5. Plant diversity effects on soil food webs are stronger than those of elevated CO2 and N deposition in a long-term grassland experiment

    PubMed Central

    Eisenhauer, Nico; Dobies, Tomasz; Cesarz, Simone; Hobbie, Sarah E.; Meyer, Ross J.; Worm, Kally; Reich, Peter B.

    2013-01-01

    Recent metaanalyses suggest biodiversity loss affects the functioning of ecosystems to a similar extent as other global environmental change agents. However, the abundance and functioning of soil organisms have been hypothesized to be much less responsive to such changes, particularly in plant diversity, than aboveground variables, although tests of this hypothesis are extremely rare. We examined the responses of soil food webs (soil microorganisms, nematodes, microarthropods) to 13-y manipulation of multiple environmental factors that are changing at global scales—specifically plant species richness, atmospheric CO2, and N deposition—in a grassland experiment in Minnesota. Plant diversity was a strong driver of the structure and functioning of soil food webs through several bottom-up (resource control) effects, whereas CO2 and N only had modest effects. We found few interactions between plant diversity and CO2 and N, likely because of weak interactive effects of those factors on resource availability (e.g., root biomass). Plant diversity effects likely were large because high plant diversity promoted the accumulation of soil organic matter in the site’s sandy, organic matter–poor soils. Plant diversity effects were not explained by the presence of certain plant functional groups. Our results underline the prime importance of plant diversity loss cascading to soil food webs (density and diversity of soil organisms) and functions. Because the present results suggest prevailing plant diversity effects and few interactions with other global change drivers, protecting plant diversity may be of high priority to maintain the biodiversity and functioning of soils in a changing world. PMID:23576722

  6. 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).

  7. 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.

  8. 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

    Marinšek, Martin; Sinkovič, Andreja

    2016-01-01

    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. 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. 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). 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.

  9. A new approach to the characterization of long-term changes in total atmospheric ozone: Applications of frequency and extreme value statistics

    SciTech Connect

    Reck, R.A.; Bornick, R.M.; Wen, G.; Frederick, J.E.; Weinberg, B.L.

    1996-02-01

    This paper sets forth a new approach for describing long-term changes in total ozone by using extreme value statistics and firquency distributions. We applied this methodology to the database of column ozone provided by the Total Ozone Mapping Spectrometer aboard Nimbus 7. We examined a geographic region measuring 7.0 degrees in latitude by 6.25 degrees in longitude in the midwestern United States from 1979--1991. On any given spring day, individual ozone measurements in this region show a large variability, where the differences between noontime maximum and minimum values sometimes exceed 100 Dobson units. During spring, the frequency of extremely low ozone values decreased over the period 1980--1991, while the opposite situation prevailed during fall.

  10. Elevated baseline plasma phospholipid protein (PLTP) levels are an independent predictor of long-term all-cause mortality in patients with diabetes mellitus and known or suspected coronary artery disease.

    PubMed

    Cavusoglu, Erdal; Marmur, Jonathan D; Chhabra, Sandeep; Hojjati, Mohammad R; Yanamadala, Sunitha; Chopra, Vineet; Eng, Calvin; Jiang, Xian-Cheng

    2015-04-01

    To investigate the long-term prognostic significance of baseline plasma PLTP levels in a group of well-characterized male patients with diabetes mellitus and known or suspected coronary artery disease referred for coronary angiography. PLTP is a plasma protein that mediates the net transfer and exchange of phospholipids between lipoproteins. It has been implicated in the pathogenesis of atherosclerosis and elevated plasma levels have been reported in patients with diabetes mellitus. Baseline plasma PLTP levels were measured in 154 male patients with diabetes mellitus who were referred for coronary angiography and followed prospectively for 5 years for the development of all-cause mortality. After adjustment for a variety of baseline clinical, angiographic and laboratory parameters, plasma PLTP levels (analyzed as a continuous variable) were an independent predictor of all-cause mortality at 5 years (HR, 1.55; 95% CI, 1.22-2.00; P = 0.0009). Furthermore, in 3 additional multivariate models that also included a wide variety of contemporary biomarkers with established prognostic efficacy (i.e., ST2, GDF-15, Cystatin C, Fibrinogen, and NT-proBNP), PLTP remained an independent predictor of all-cause mortality at 5 years. Elevated baseline plasma levels of PLTP are associated with an increased risk of long-term all-cause mortality in patients with diabetes and known or suspected coronary disease. Furthermore, this association is independent of a variety of clinical, angiographic, and laboratory variables, including a whole host of contemporary biomarkers with established prognostic efficacy. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

    DOE PAGES

    Darbah, Joseph N. T.; Kubiske, Mark E.; Nelson, Neil; ...

    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

  12. Impacts of elevated atmospheric CO2 and O3 on paper birch (Betula papyrifera): reproductive fitness.

    PubMed

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

    2007-03-21

    Atmospheric CO2 and tropospheric O3 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 CO2 and O3 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 CO2 increased both male and female flower production, while elevated O3 increased female flower production compared to trees in control rings. Interestingly, very little flowering has yet occurred in combined treatment. Elevated CO2 had significant positive effect on birch catkin size, weight, and germination success rate (elevated CO2 increased germination rate of birch by 110% compared to ambient CO2 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 O3 (elevated O3 decreased the germination rate of birch by 62%, decreased seed weight by 25%, and increased root length by 15%). Under elevated CO2, 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 CO2, while the reverse was true for seedlings from seeds produced under the elevated O3. 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 CO2 and O3 can dramatically affect flowering, seed production, and seed quality of paper birch, affecting reproductive fitness of this species.

  13. TERENO ("Terrestrial Environmental Observatories"): Establishment and Upgrading of a Terrestrial Observatory "Alpine upland" for Long Term Observations of the Impact of Global Change Factors on Biosphere-Hydrosphere-Atmosphere Interactions

    NASA Astrophysics Data System (ADS)

    Kunstmann, H.; Papen, H.; Butterbach-Bahl, K.; Kiese, R.; Marx, A.; Schmid, H.

    2007-12-01

    Long term observations are an indispensable pre-requisite to improve our knowledge of the complex biosphere- hydrosphere-atmosphere (BHA)-interactions and to detect and analyze the impact of Global Change parameters on these interactions as well as to develop, improve and validate BHA model systems. As an integral part of the Helmholtz initiative TERENO to establish/upgrade and equip terrestrial observatories for long term observations (> 10 years) on the effects of Global Change on complex terrestrial ecosystems, an observatory "Alpine Upland", operated jointly by the research centers FZK (Forschungszentrum Karlsruhe) and GSF (National Research Center for Environment and Health) is established. The central objectives of the scientific work performed by Forschungszentrum Karlsruhe within this observatory are: Characterization and quantification of changes of the (a) coupled C-/N-cycles and C-/N-storage (b)biosphere-atmosphere exchange (trace gases/energy flux/albedo) (c)vegetation and microbial biodiversity and of the temporal dynamics of matter- turnover and -exchange coupled to this change in biodiversity (d)terrestrial hydrology (alpine water budget, precipitation variability, extreme hydrometeorological events, seapage water quality/quantity, water retention capacity) in important climate- and use-sensitive ecosystem types within the pre-alpine region (e.g. alpine meadows, forests) under changing conditions of climate, management and nutrient deposition (atmospheric N-input). Besides upgrading of the already existing long term observation stations in the pre-alpine region ("The Höglwald Forest" (FZK) and the agricultural long term observation station "Scheyern" (for details see separate contribution of GSF) FZK will establish a "Climate-Feedback Observatory" at which the effects of predicted future changes in temperature and precipitation amount/distribution within the pre-alpine region on the complex BHA interactions will be studied applying a long term in

  14. Long-Term Continuous Isotopic Ratio Measurements of Atmospheric CO2 Using a 4.3 Micron Pulsed Quantum Cascade Laser

    NASA Astrophysics Data System (ADS)

    Nelson, D. D.; McManus, J. B.; Herndon, S. C.; Zahniser, M. S.

    2007-12-01

    Real time methods to monitor the stable isotopic ratios of carbon dioxide are needed to quantify the sources and sinks of this centrally important greenhouse gas. This is an extreme instrumental challenge since the ratios need to be measured with an accuracy of at least one part in ten thousand or 0.1 ". We use tunable infrared laser differential absorption spectroscopy with pulsed QC lasers (QC-TILDAS) to address this challenge. QC lasers are attractive optical sources due to: 1) absence of cryogenic fluids, 2) stable single mode spectral output, 3) optical simplicity. Our optical system employs a dual-cell arrangement with ambient air flowing through the sample cell and a reference gas flowing through the reference cell. Both 13C/12C and 18O/16O ratios can be obtained in a single spectral window near 2310 cm-1. Spectral analysis is applied to the ratio of the sample and reference spectra, canceling correlated noise components. Because the absorption lines of the isotopic species have different temperature dependences, temperature stability is critical. The optical system is temperature controlled and the two multipass cells are thermally coupled and individually monitored with a precision of 1 mK. The ratio technique compensates for temperature sensitivity, as well as for drifts in laser line width, frequency, tuning rate and power variation. The long term stability of the thermally stabilized dual-cell QCL system has been evaluated using the Allan variance technique. The Allan plot shows a 1-sec RMS noise of 0.2 per mil, and a minimum RMS noise of 0.03 per mil after 300 sec integration using a liquid nitrogen cooled detector. We have used this instrument to perform long term (more than 6 months) monitoring of ambient air from the roof top of our laboratory. The data show variations in R13 and R18 that follow diurnal cycles. Winter data show clear correlations with morning and evening signatures of local automobile traffic. Data collected during spring are

  15. 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.

  16. 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.

  17. Long-term simulation of human exposure to atmospheric perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) in the Osaka urban area, Japan.

    PubMed

    Niisoe, Tamon; Harada, Kouji H; Ishikawa, Hirohiko; Koizumi, Akio

    2010-10-15

    A publicly available atmospheric transport model, the Weather Research and Forecasting Chemistry Model ( http://ruc.noaa.gov/wrf/WG11/ ), was used to simulate atmospheric perfluorooctanoic acid (PFOA) and perfluorooctanoate (PFO) emitted from a point source in the Osaka urban area (also known as Keihanshin), Japan. The time period of the simulation was from 1983 to 2008. The modeled air concentrations were highly correlated (r = 0.91) with the observed air concentrations. Intake levels by inhalation of simulated air concentrations and through the gastrointestinal tract as estimated by the food duplicate method were input to a pharmacokinetic model of the human body to simulate serum concentrations of PFOA and PFO (PFO(A)). For validation of the atmospheric model, simulated values were compared with those observed in serum samples. The simulated values generally agreed with those observed in serum samples from residents of the Keihanshin area (r = 0.93). It was confirmed that the atmospheric model was generally capable of projecting features of atmospheric PFO(A) as well as serum concentrations of PFO(A) in this case. The results indicated a dominant contribution of the atmospheric component to serum PFO(A) in humans near the point source in the Keihanshin area. In 2008, that contribution was about 70%.

  18. Long-term prognostic value of admission haemoglobin A1c (HbA1c) levels in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

    PubMed Central

    Akgul, Ozgur; Cakmak, Huseyin Altug; Erturk, Mehmet; Surgit, Ozgur; Celik, Omer; Ozturk, Derya; Uzun, Fatih; Akkaya, Emre; Yildirim, Aydın

    2014-01-01

    Introduction Many studies have reported the diagnostic and prognostic value of haemoglobin A1c (HbA1c) levels in patients with acute coronary syndrome. However, the short- and long-term prognostic value of HbA1c level in patients with ST elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI) is controversial. Aim To investigate whether admission HbA1c level has a prognostic value for in-hospital, short-, and long-term cardiovascular (CV) mortality and major adverse cardiovascular events in patients with STEMI undergoing primary PCI. Material and methods This prospective study included 443 consecutive patients with STEMI who underwent primary PCI between September 2010 and July 2012. The patients were divided into three groups based on admission HbA1c levels: group I (HbA1c ≤ 5.6%), group II (HbA1c 5.7–6.4%), and group III (HbA1c ≥ 6.5%). The in-hospital, 1-month, and 1-year CV events of all 3 patient groups were followed up. Results A significant association was found between HbA1c level and 1-year primary clinical outcomes, including CV mortality, non-fatal reinfarction, and stroke (p = 0.037). In addition, age, Killip class > 1, and left ventricular ejection fraction were found to be independent predictors of long-term CV mortality in multivariate analysis (hazard ratios (95% confidence interval) 1.081 (1.020–1.146), 4.182 (1.171–14.935), and 0.832 (0.752–0.920); p = 0.009, p = 0.028, and p < 0.001, respectively). Conclusions In this study, we demonstrated that increased admission HbA1c levels were associated with higher rates of major adverse CV events, including mortality, non-fatal reinfarction, and stroke, in patients with STEMI who underwent primary PCI. PMID:25489302

  19. Long-term statin therapy in patients with systolic heart failure and normal cholesterol: effects on elevated serum markers of collagen turnover, inflammation, and B-type natriuretic peptide.

    PubMed

    Abulhul, Esam; McDonald, Kenneth; Martos, Ramon; Phelan, Dermot; Spiers, J Paul; Hennessy, Martina; Baugh, John; Watson, Chris; O'Loughlin, Christina; Ledwidge, Mark

    2012-01-01

    The role of statin therapy in heart failure (HF) is unclear. The amino-terminal propeptide of procollagen type III (PIIINP) predicts outcome in HF, and yet there are conflicting reports of statin therapy effects on PIIINP. This study determined whether there was an increase in serum markers of inflammation, fibrosis (including PIIINP), and B-type natriuretic peptide (BNP) in patients with systolic HF and normal total cholesterol and determined the effects of long-term treatment with atorvastatin on these markers. Fifty-six white patients with systolic HF and normal cholesterol levels (age 72 [13] years; 68% male; body mass index 27.0 [7.3] kg/m(2); ejection fraction 35 [13]%; 46% with history of smoking) were randomly allocated to atorvastatin treatment for 6 months, titrated to 40 mg/d (A group) or not (C group). Age- and/or sex-matched subjects without HF (N group) were also recruited. Biomarkers were measured at baseline (all groups) and 6 months (A and C groups). Serum markers of collagen turnover, inflammation, and BNP were significantly elevated in HF patients compared with normal participants (all P < 0.05). There were correlations between these markers in HF patients but not in normal subjects. Atorvastatin treatment for 6 months caused a significant reduction in the following biomarkers compared with baseline: BNP, from median (interquartile range) 268 (190-441) pg/mL to 185 (144-344) pg/mL; high-sensitivity C-reactive protein (hs-CRP), from 5.26 (1.95 -9.29) mg/L to 3.70 (2.34-6.81) mg/L; and PIIINP, from 4.65 (1.86) to 4.09 (1.25) pg/mL (all P < 0.05 baseline vs 6 months). Between-group differences were significant for PIIINP only (P = 0.027). There was a positive interaction between atorvastatin effects and baseline hs-CRP and PIIINP (P < 0.01). Long-term statin therapy reduced PIIINP in this small, selected HF population with elevated baseline levels. Further evaluation of statin therapy in the management of HF patients with elevated PIIINP is

  20. Long-term safety and feasibility of three-vessel multimodality intravascular imaging in patients with ST-elevation myocardial infarction: the IBIS-4 (integrated biomarker and imaging study) substudy.

    PubMed

    Taniwaki, Masanori; Radu, Maria D; Garcia-Garcia, Hector M; Heg, Dik; Kelbæk, Henning; Holmvang, Lene; Moschovitis, Aris; Noble, Stephane; Pedrazzini, Giovanni; Saunamäki, Kari; Dijkstra, Jouke; Landmesser, Ulf; Wenaweser, Peter; Meier, Bernhard; Stefanini, Giulio G; Roffi, Marco; Lüscher, Thomas F; Windecker, Stephan; Räber, Lorenz

    2015-06-01

    We assessed the feasibility and the procedural and long-term safety of intracoronary (i.c) imaging for documentary purposes with optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in patients with acute ST-elevation myocardial infarction (STEMI) undergoing primary PCI in the setting of IBIS-4 study. IBIS4 (NCT00962416) is a prospective cohort study conducted at five European centers including 103 STEMI patients who underwent serial three-vessel coronary imaging during primary PCI and at 13 months. The feasibility parameter was successful imaging, defined as the number of pullbacks suitable for analysis. Safety parameters included the frequency of peri-procedural complications, and major adverse cardiac events (MACE), a composite of cardiac death, myocardial infarction (MI) and any clinically-indicated revascularization at 2 years. Clinical outcomes were compared with the results from a cohort of 485 STEMI patients undergoing primary PCI without additional imaging. Imaging of the infarct-related artery at baseline (and follow-up) was successful in 92.2% (96.6%) of patients using OCT and in 93.2% (95.5%) using IVUS. Imaging of the non-infarct-related vessels was successful in 88.7% (95.6%) using OCT and in 90.5% (93.3%) using IVUS. Periprocedural complications occurred <2.0% of OCT and none during IVUS. There were no differences throughout 2 years between the imaging and control group in terms of MACE (16.7 vs. 13.3%, adjusted HR1.40, 95% CI 0.77-2.52, p = 0.27). Multi-modality three-vessel i.c. imaging in STEMI patients undergoing primary PCI is consistent a high degree of success and can be performed safely without impact on cardiovascular events at long-term follow-up.

  1. 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

  2. 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.

  3. 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.

  4. Statistical analysis of long-term monitoring data for persistent organic pollutants in the atmosphere at 20 monitoring stations broadly indicates declining concentrations.

    PubMed

    Kong, Deguo; MacLeod, Matthew; Hung, Hayley; Cousins, Ian T

    2014-11-04

    During recent decades concentrations of persistent organic pollutants (POPs) in the atmosphere have been monitored at multiple stations worldwide. We used three statistical methods to analyze a total of 748 time series of selected POPs in the atmosphere to determine if there are statistically significant reductions in levels of POPs that have had control actions enacted to restrict or eliminate manufacture, use and emissions. Significant decreasing trends were identified in 560 (75%) of the 748 time series collected from the Arctic, North America, and Europe, indicating that the atmospheric concentrations of these POPs are generally decreasing, consistent with the overall effectiveness of emission control actions. Statistically significant trends in synthetic time series could be reliably identified with the improved Mann-Kendall (iMK) test and the digital filtration (DF) technique in time series longer than 5 years. The temporal trends of new (or emerging) POPs in the atmosphere are often unclear because time series are too short. A statistical detrending method based on the iMK test was not able to identify abrupt changes in the rates of decline of atmospheric POP concentrations encoded into synthetic time series.

  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. 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.

  7. Long-term urethral catheterisation.

    PubMed

    Turner, Bruce; Dickens, Nicola

    This article discusses long-term urethral catheterisation, focusing on the relevant anatomy and physiology, indications for the procedure, catheter selection and catheter care. It is important that nurses have a good working knowledge of long-term catheterisation as the need for this intervention will increase with the rise in chronic health conditions and the ageing population.

  8. 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

  9. Modelling of the long term fate of pesticide residues in agricultural soils and their surface exchange with the atmosphere: Part I. Model description and evaluation.

    PubMed

    Scholtz, M T; Bidleman, T F

    2006-09-15

    Sources of pesticides in the atmosphere can be releases of new material through current use, or emission/reemission from soil residues resulting from historical use. It is the latter aspect, soil residues, that is the focus of this study. This paper describes the application of a simple coupled atmosphere-soil pesticide exchange model that can assist in the interpretation of soil residue and air concentration measurements, and in the projection of short period field measurements to larger spatial scales and longer time periods. Only dry gaseous exchange (emission and deposition) between bare agricultural lands and the atmosphere is modelled. Wet deposition and particle associated deposition of pesticide are not included. Model results are compared with published co-located air and soil pesticide concentration measurements made on agricultural lands in the southern U.S. that have soil residues of lindane and the following six highly persistent pesticides: cis-, trans-chlordane, p,p'-DDE, dieldrin, trans-nonachlor and toxaphene. The study results show: (i) that measured air concentrations of toxaphene and p,p'-DDE above agricultural soils in the southern U.S. can be attributed to emissions due to local soil residues of these pesticides rather than to the regional background air concentrations; (ii) that both soil emissions and background air concentrations of dieldrin contribute significantly to the measured air concentrations; (iii) that measured air concentrations of cis- and trans-chlordane as well as trans-nonachlor and lindane are mainly due to the regional background with little contribution from local soil residues. An analysis of modelled summer day and night average soil-air exchange fluxes shows that toxaphene and p,p'-DDE soil residues are strong sources of emission to the atmosphere during both the day and night while the chlordanes, trans-nonachlor, lindane and dieldrin are deposited from the atmosphere to the soil during the night hours and emitted to

  10. Tolerance of a field grown soybean cultivar to elevated ozone level is concurrent with higher leaflet ascorbic acid level, higher ascorbate-dehydroascorbate redox status, and long term photosynthetic productivity.

    PubMed

    Michael Robinson, J; Britz, S J

    2000-01-01

    We examined the characteristics of ascorbic acid (ASC) level, dehydroascorbate (DHA) level, and the ASC-DHA redox status in the leaflets of two soybean cultivars grown in a field environment and exposed to elevated ozone (O(3)) levels. These two cultivars, one that preliminary evidence indicated to be O(3)-tolerant (cv Essex), and one that was indicated to be O(3)-sensitive (cv Forrest), were grown in open-top chambers during the summer of 1997. The plants were exposed daily to a controlled, moderately high O(3) level ( approximately 58 nl l(-1) air) in the light, beginning at the seedling stage and continuing to bean maturity. Concurrently, control plants were exposed to carbon-filtered, ambient air containing a relatively low O(3) level ( approximately 24 nl l(-1) air) during the same period. Elevated O(3) did not affect biomass per plant, mature leaf area accretion, or bean yield per plant of cv Essex. In contrast, elevated O(3) level decreased the biomass and bean yield per plant of cv Forrest by approximately 20%. Daily leaflet photosynthesis rate and stomatal conductance per unit area did not decrease in either cultivar as a result of prolonged O(3) exposure. A 10% lower mature leaflet area in O(3)-treated cv Forrest plants contributed to an ultimate limitation in long-term photosynthetic productivity (vegetative and bean yield). Possible factors causing cv Essex to be more O(3) tolerant than cv Forrest were: 1) mature leaflets of control and O(3)-treated cv Essex plants consistently maintained a higher daily ASC level than leaflets of cv Forrest plants, and 2) mature leaflets of cv Essex plants maintained a higher daily ASC-DHA redox status than leaflets of cv Forrest plants.

  11. 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.

  12. Long-term ground-based microwave radiometric measurements of atmospheric brightness temperature in SKYNET Hefei (31.90N, 117.17E) site

    NASA Astrophysics Data System (ADS)

    Wang, Zhenzhu; Liu, Dong; Xie, Chenbo; Wang, Bangxin; Zhong, Zhiqing; Wang, Yingjian; Chen, Bin

    2017-02-01

    A dual-frequency, ground-based microwave radiometer (WVR-1100) is used to investigate the behavior of the atmosphere in terms of zenith brightness temperature (TB) at 23.8 and 31.4 GHz respectively. Some experimental findings in SKYNET Hefei site from September 2002 to August 2012 are presented. The cumulative distributions of TB at both frequencies for all sky conditions show four different regions, while only two regions can be identified for clear, lightly cloudy and cloudy condition. Annual cycle of TB at 23.8 GHz is apparently remarkable, indicating the large annual cycle of atmospheric water vapor. Regular seasonal variations of TB are observed with the strongest value in summer and the weakest in winter.

  13. 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.

  14. Long term atmospheric deposition as the source of nitrate and other salts in the Atacama Desert, Chile: New evidence from mass-independent oxygen isotopic compositions

    USGS Publications Warehouse

    Michalski, Greg; Böhlke, J.K.; Thiemens , Mark

    2004-01-01

    Isotopic analysis of nitrate and sulfate minerals from the nitrate ore fields of the Atacama Desert in northern Chile has shown anomalous 17O enrichments in both minerals. Δ17O values of 14–21 ‰ in nitrate and 0.4 to 4 ‰ in sulfate are the most positive found in terrestrial minerals to date. Modeling of atmospheric processes indicates that the Δ17O signatures are the result of photochemical reactions in the troposphere and stratosphere. We conclude that the bulk of the nitrate, sulfate and other soluble salts in some parts of the Atacama Desert must be the result of atmospheric deposition of particles produced by gas to particle conversion, with minor but varying amounts from sea spray and local terrestrial sources. Flux calculations indicate that the major salt deposits could have accumulated from atmospheric deposition in a period of 200,000 to 2.0 M years during hyper-arid conditions similar to those currently found in the Atacama Desert. Correlations between Δ17O and δ18O in nitrate salts from the Atacama Desert and Mojave Desert, California, indicate varying fractions of microbial and photochemical end-member sources. The photochemical nitrate isotope signature is well preserved in the driest surficial environments that are almost lifeless, whereas the microbial nitrate isotope signature becomes dominant rapidly with increasing moisture, biologic activity, and nitrogen cycling. These isotopic signatures have important implications for paleoclimate, astrobiology, and N cycling studies.

  15. 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.

  16. Long term observations of halogenated greenhouse gases in a European continental background station for assessing atmospheric trends, annual growth rates and emission sources

    NASA Astrophysics Data System (ADS)

    Maione, M.; Arduini, J.; Uguccioni, F.; Giostra, U.; Furlani, F.; Belfiore, L.; Cava, D.

    2009-04-01

    Climate altering halocarbons are continuously monitored at the atmospheric research station "O. Vittori" located on the top of Monte Cimone, Northern Apennines, Italy ( 2165 m asl), in the frame of the SOGE (System for Observation of halogenated Greenhouse gases in Europe) network, an integrated system based on a combination of observations and models aimed at assessing atmospheric trends, annual growth rates and at estimating European halocarbon emissions. The use of such a top-down approach is useful to ascertain compliance to International Protocols regulating production/emission of halogenated greenhouse gases. Establishing the baseline is essential both for estimating annual growth rates and because back attribution techniques are based on the clear identification of "above the background" data. That is particularly challenging in a Station like Monte Cimone characterised by a complex meteorological and source field. The approach proposed is based on the identification of the lowest concentration values in a given temporal range to which a ∆c representing variation due to instrumental error is added. Trends are evaluated by using a non-linear regression function, able to take into account both annual and seasonal variation. In order to identify source, regions baseline data are subtracted from the full data set and an inversion modelling cascade, which makes use of MM5 model to reproduce meteorological fields and of FLEXPART to simulate tracer dispersion, is used to find the best emissions map that fits the observations.

  17. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Shallow-to-Deep Convection Transition over Land: Atmospheric and surface controls inferred from long-term ground-based observations

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Klein, S. A.

    2016-12-01

    Warm-season decade-long observations are used to investigate mechanisms controlling the transition from shallow to deep convection over land. The data are from the DOE Atmospheric Radiation Measurement Climate Research Facility Southern Great Plains site. The study focuses on two questions: 1) what environmental parameters differ between the two convective regimes: fair-weather shallow cumulus versus late-afternoon deep convection, especially in the late morning a few hours before deep convection begins? And 2) Do convective regimes such as fair-weather shallow cumulus and late-afternoon deep convection have any preferences over soil moisture conditions (dry or wet) and soil moisture heterogeneities? It is found that a more humid environment immediately above the boundary layer is present before the start of late afternoon heavy precipitation events. Greater boundary layer inhomogeneity in moist static energy, temperature, moisture, and horizontal wind before precipitation begins is correlated to larger rain rates at the initial stage of precipitation. Late-afternoon deep convection tends to prefer drier soil conditions with larger surface heterogeneity. This observational study helps our understanding of convective responses to different environmental factors especially surface versus atmospheric controls. This work leads to the establishment of composite cases of different continental convective regimes for large-eddy simulations and single-column tests of climate model parameterizations. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-698972

  19. Functional mitral regurgitation after a first non-ST segment elevation acute coronary syndrome: very-long-term follow-up, prognosis and contribution to left ventricular enlargement and atrial fibrillation development.

    PubMed

    Núñez-Gil, Iván J; Estrada, Irene; Pérez de Isla, Leopoldo; Feltes, Gisela; De Agustín, José Alberto; Vivas, David; Viana-Tejedor, Ana; Escaned, Javier; Alfonso, Fernando; Jiménez-Quevedo, Pilar; García-Fernández, Miguel A; Macaya, Carlos; Fernández-Ortiz, Antonio

    2013-10-01

    To assess the relationship between functional mitral regurgitation (MR) after a non-ST segment elevation acute coronary syndrome (NSTSEACS) and long-term prognosis, ventricular remodelling and further development of atrial fibrillation (AF), since functional MR is common after myocardial infarction. Prospective cohort study conducted in a tertiary referral centre. We prospectively studied 237 patients consecutively discharged in New York Heart Association class I-II (74% men; mean age 66.1 years) after a first NSTSEACS. All underwent an ECG the first week after admission and were echocardiographically and clinically followed-up (median 6.95 years). MR was detected in 95 cases (40.1%) and became an independent risk factor for the development of heart failure (HF) and major adverse cardiovascular events (MACE) (per MR degree, HRHF 1.71, 95% CI 1.138 to 2.588, p=0.01; HRMACE 1.49, 95% CI 1.158 to 1.921, p=0.002). Left ventricular diastolic (grade I 12.7±40.7; grade II 26.8±12.4; grade III 46.3±50.9 mL, p=0.01) and systolic (grade I 10.4±37.3; grade II 10.12±12.7; grade III 36.8±46.0 mL, p=0.02) mean volumes were higher after follow-up in patients with MR, in proportion to the initial degree of MR. In the rhythm analysis (126 patients; previously excluding those with any history of AF) during follow-up, 11.4% of patients with degree I MR, 14.3% with degree II MR and 75% with degree III MR developed AF, while only 5.1% of those with degree 0 developed AF, p<0.001. MR is common after an NSTSEACS. The presence and greater degree of MR confers a worse long-term prognosis after a first NSTSEACS. This can in part be explained by increased negative ventricular remodelling and increased occurrence of AF.

  20. Long-term Variation of Temperatures and Wind Velocities from Earth based Doppler-wind and Temperature Measurements in Venus Upper Atmosphere between 1990 and 2013 using the Infrared Heterodyne Spectrometer THIS

    NASA Astrophysics Data System (ADS)

    Sornig, Manuela; Stangier, Tobias; Krause, Pia; Wischnewski, Caro; Kostiuk, Ted; Livengood, Tim

    2014-05-01

    Dynamics of the Venusian atmospheric transition zone between the sub-solar to anti-solar (SS-AS) flow dominated region above 120km and the superrotation dominated region below 90 km is not yet fully understood. Temperatures in the same region are not very well constrained and we lack in a comprehensive understanding of this atmospheric region. Therefore direct measurements of these parameters on various time scales and on different locations on the planet are essential for validation of global circulation models and a comprehensive understanding of the atmosphere. Such observations can be provided by the infrared heterodyne spectrometers THIS (University of Cologne) and HIPWAC (NASA GSFC). Operating around 10μm both instruments fully resolve CO2 non-LTE emission lines for Doppler-wind and temperature retrievals at an pressure level of 1μbar (~110 km). In addition to this "one-altitude" information the broader CO2 absorption lines can be used to gain information about the temperature profile lower down in the atmosphere (~60-90 km). Long term variability in Doppler-wind velocities and temperature at ~110km from campaigns between 1990 to 2013 will be presented. A report about local wave activities will be included. In addition recently retrieved temperature profiles from 60 to 90 km will be shown.

  1. 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.

  2. Response of potato to discontinuous exposures of atmospheric ethylene: results of a long-term experiment in open-top chambers and crop growth modelling

    NASA Astrophysics Data System (ADS)

    Dueck, Th. A.; Van Dijk, C. J.; Grashoff, C.; Groenwold, J.; Schapendonk, A. H. C. M.; Tonneijck, A. E. G.

    A field experiment in open-top chambers (OTCs) was performed to quantitatively assess the growth and yield response of potato to discontinuous exposures to atmospheric ethylene (200, 400 and 800 ppb, applied twice weekly and 200 and 400 ppb applied 4 times weekly, each for 3 h/event). To evaluate the effect of ethylene on potato tuber yield, a module was developed for an existing crop growth simulation model by incorporating the effects of ethylene on epinasty and photosynthesis. Explorations with the model showed that in a worst case scenario, ethylene-induced epinasty had only a marginal effect on tuber yield. Short-term exposures to ethylene under laboratory conditions inhibited photosynthesis, but it recovered within 48 h. When exposed to ethylene for longer than 12 h, irreversible damage of the photosynthesis apparatus occurred. Exposure to ethylene in the OTCs resulted in epinasty and reduced flowering. The number of flowers on potato decreased with increasing concentrations of ethylene, irrespective of the exposure frequency. Calculations showed that the number of flowers was significantly reduced at ca. 170 ppb ethylene, averaged over the hours of exposure. Ethylene concentrations up to 800 ppb, administered 4 times weekly for 3 h during the growing season, did not affect vegetative growth and yield in fumigated potatoes. Under these experimental conditions, the modified simulation model incorporating the effects of ethylene on epinasty and photosynthesis forecasts a 5% effect on tuber yield at concentrations of 1600 ppb. All results indicate that ethylene concentrations higher than 800 ppb are required to adversely affect tuber yield of potato.

  3. The Isotopic Record of Elevation Thresholds in Continental Plateaus to Atmospheric Circulation

    NASA Astrophysics Data System (ADS)

    Mulch, A.; Chamberlain, C. P.; Graham, S. A.; Teyssier, C.; Cosca, M. A.

    2011-12-01

    High-elevation orogenic plateaus and mountain ranges exert a strong control on global climate and precipitation patterns and interact with lithospheric and upper mantle tectonic processes as well as atmospheric circulation. Reconstructing the history of surface elevation thus not only provides a critical link between erosional and tectonic processes but also ties Earth surface processes to the long-term climate history of our planet. This interaction, however, has important implications when using stable isotopes (O, H) as proxies for landscape and terrestrial climate evolution as interacting land surface properties (elevation, relief, vegetation cover) and atmospheric circulation patterns (upstream moisture path) may attain threshold conditions that can cloak or amplify the impact of topography on isotopes in precipitation. A large number of stable isotope studies in lacustrine and pedogenic environments of intermontane basins record the isotopic and sedimentologic fingerprint of the evolving landscape of the Cenozoic western North American Cordillera. In general we observe the onset of strong oxygen isotope in precipitation gradients along the eastward and westward flanks of the Cordilleran orogen and associated 18O-depleted moisture within the Cordilleran hinterland to develop no later than 50-55 Ma in British Columbia and Washington, 49 Ma in Montana, and 39-40 Ma in Nevada. However, some of these shifts to very low oxygen isotope compositions in meteoric water occur at rates that by far exceed those that could be attributed to tectonic surface uplift alone. Here we present a multi-proxy approach from the Elko Basin (NV) that ties stable and radiogenic tracers of landscape evolution with high resolution Ar-Ar geochronology. In pedogenic and lacustrine deposits of the Elko basin we observe a change in oxygen isotope ratios that is far too large (6-8 %) and rapid (<200 000 a) to be solely due to changes in elevation. Rather we suggest that the combined effects of

  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. 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) .

  6. Long-term parenteral nutrition

    PubMed Central

    Ladefoged, Karin; Jarnum, Stig

    1978-01-01

    Nineteen patients (11 women and eight men) aged 20-68 received long-term parenteral nutrition, mostly at home, for six to 63 months (mean 19 months). Indications for LTPN were extensive, active Crohn's disease in three patients, intestinocutaneous fistulas in three, and short-bowel syndrome in the remaining 13 patients. Subclavian or intra-atrial (Broviac) catheters were most commonly used, for which the average life was four and seven months respectively. Complications of long-term parenteral nutrition included pneumothorax in four out of 48 subclavian vein punctures. Catheter-induced thrombosis of central veins was shown by phlebography 17 times in nine patients, and eight episodes of total occlusion occurred. Two of these patients had pulmonary infarction. Nineteen episodes of catheter sepsis occurred in 11 patients, but only one was fatal. Complications related to intestinal disease included intra-abdominal abscesses and intestinal fistulas, and disturbances of liver function. Five patients died, though in only two was death related to long-term parenteral nutrition. One of these patients died from catheter sepsis, the other had subdural haematoma possibly caused by anticoagulant treatment. Eight of the 14 surviving patients still needed parenteral nutrition. All received a disability pension, but six had an acceptable quality of life with almost normal social activities. Despite problems such as difficulties in maintaining standardised infusion programmes, it was concluded that long-term parenteral nutrition at home is practicable and consistent with an acceptable quality of life. ImagesFIG 2 PMID:98199

  7. Interpolating atmospheric water vapor delay by incorporating terrain elevation information

    NASA Astrophysics Data System (ADS)

    Xu, W. B.; Li, Z. W.; Ding, X. L.; Zhu, J. J.

    2011-09-01

    In radio signal-based observing systems, such as Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR), the water vapor in the atmosphere will cause delays during the signal transmission. Such delays vary significantly with terrain elevation. In the case when atmospheric delays are to be eliminated from the measured raw signals, spatial interpolators may be needed. By taking advantage of available terrain elevation information during spatial interpolation process, the accuracy of the atmospheric delay mapping can be considerably improved. This paper first reviews three elevation-dependent water vapor interpolation models, i.e., the Best Linear Unbiased Estimator in combination with the water vapor Height Scaling Model (BLUE + HSM), the Best Linear Unbiased Estimator coupled with the Elevation-dependent Covariance Model (BLUE + ECM), and the Simple Kriging with varying local means based on the Baby semi-empirical model (SKlm + Baby for short). A revision to the SKlm + Baby model is then presented, where the Onn water vapor delay model is adopted to substitute the inaccurate Baby semi-empirical model (SKlm + Onn for short). Experiments with the zenith wet delays obtained through the GPS observations from the Southern California Integrated GPS Network (SCIGN) demonstrate that the SKlm + Onn model outperforms the other three. The RMS of SKlm + Onn is only 0.55 cm, while those of BLUE + HSM, BLUE + ECM and SKlm + Baby amount to 1.11, 1.49 and 0.77 cm, respectively. The proposed SKlm + Onn model therefore represents an improvement of 29-63% over the other known models.

  8. 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.

  9. 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

  10. 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

  11. A long-term climatology of medicanes

    NASA Astrophysics Data System (ADS)

    Cavicchia, Leone; von Storch, Hans; Gualdi, Silvio

    2014-09-01

    Medicanes, intense and destructive mesoscale cyclones exhibiting several similarities with tropical hurricanes, are known to struck occasionally the Mediterranean Sea. Thanks to a high-resolution dynamical downscaling effort, we are able to study for the first time the long-term climatology of those rare storms in a systematic way. The distribution of medicanes frequency in space and time is discussed, and the environmental factors responsible for their formation are investigated. We find that medicanes develop in those areas of the Mediterranean region where intrusions of cold air in the upper troposphere can produce configurations of thermodynamical disequilibrium of the atmosphere similar to those associated with the formation of tropical cyclones.

  12. Impacts of elevated atmospheric CO2 and O3 on Paper Birch (Betula papyrifera): reproductive fitness

    Treesearch

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

    2007-01-01

    Atmospheric CO2 and tropospheric O3 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 CO2 and O3 for paper birch...

  13. Impacts of 3 years of elevated atmospheric CO2 on rhizosphere carbon flow and microbial community dynamics.

    PubMed

    Drigo, Barbara; Kowalchuk, George A; Knapp, Brigitte A; Pijl, Agata S; Boschker, Henricus T S; van Veen, Johannes A

    2013-02-01

    Carbon (C) uptake by terrestrial ecosystems represents an important option for partially mitigating anthropogenic CO2 emissions. Short-term atmospheric elevated CO2 exposure has been shown to create major shifts in C flow routes and diversity of the active soil-borne microbial community. Long-term increases in CO2 have been hypothesized to have subtle effects due to the potential adaptation of soil microorganism to the increased flow of organic C. Here, we studied the effects of prolonged elevated atmospheric CO2 exposure on microbial C flow and microbial communities in the rhizosphere. Carex arenaria (a nonmycorrhizal plant species) and Festuca rubra (a mycorrhizal plant species) were grown at defined atmospheric conditions differing in CO2 concentration (350 and 700 ppm) for 3 years. During this period, C flow was assessed repeatedly (after 6 months, 1, 2, and 3 years) by (13) C pulse-chase experiments, and label was tracked through the rhizosphere bacterial, general fungal, and arbuscular mycorrhizal fungal (AMF) communities. Fatty acid biomarker analyses and RNA-stable isotope probing (RNA-SIP), in combination with real-time PCR and PCR-DGGE, were used to examine microbial community dynamics and abundance. Throughout the experiment the influence of elevated CO2 was highly plant dependent, with the mycorrhizal plant exerting a greater influence on both bacterial and fungal communities. Biomarker data confirmed that rhizodeposited C was first processed by AMF and subsequently transferred to bacterial and fungal communities in the rhizosphere soil. Over the course of 3 years, elevated CO2 caused a continuous increase in the (13) C enrichment retained in AMF and an increasing delay in the transfer of C to the bacterial community. These results show that, not only do elevated atmospheric CO2 conditions induce changes in rhizosphere C flow and dynamics but also continue to develop over multiple seasons, thereby affecting terrestrial ecosystems C utilization processes

  14. Interactive effects of seasonal drought and elevated atmospheric carbon dioxide concentration on prokaryotic rhizosphere communities.

    PubMed

    Drigo, Barbara; Nielsen, Uffe N; Jeffries, Thomas C; Curlevski, Nathalie J A; Singh, Brajesh K; Duursma, Remko A; Anderson, Ian C

    2017-08-01

    Global change models indicate that rainfall patterns are likely to shift towards more extreme events concurrent with increasing atmospheric carbon dioxide concentration ([CO2 ]). Both changes in [CO2 ] and rainfall regime are known to impact above- and belowground communities, but the interactive effects of these global change drivers have not been well explored, particularly belowground. In this experimental study, we examined the effects of elevated [CO2 ] (ambient + 240 ppm; [eCO2 ]) and changes in rainfall patterns (seasonal drought) on soil microbial communities associated with forest ecosystems. Our results show that bacterial and archaeal communities are highly resistant to seasonal drought under ambient [CO2 ]. However, substantial taxa specific responses to seasonal drought were observed at [eCO2 ], suggesting that [eCO2 ] compromise the resistance of microbial communities to extreme events. Within the microbial community we were able to identify three types of taxa specific responses to drought: tolerance, resilience and sensitivity that contributed to this pattern. All taxa were tolerant to seasonal drought at [aCO2 ], whereas resilience and sensitivity to seasonal drought were much greater in [eCO2 ]. These results provide strong evidence that [eCO2 ] moderates soil microbial community responses to drought in forests, with potential implications for their long-term persistence and ecosystem functioning. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Association of onset to balloon and door to balloon time with long term clinical outcome in patients with ST elevation acute myocardial infarction having primary percutaneous coronary intervention: observational study.

    PubMed

    Shiomi, Hiroki; Nakagawa, Yoshihisa; Morimoto, Takeshi; Furukawa, Yutaka; Nakano, Akira; Shirai, Shinichi; Taniguchi, Ryoji; Yamaji, Kyohei; Nagao, Kazuya; Suyama, Tamaki; Mitsuoka, Hirokazu; Araki, Makoto; Takashima, Hiroyuki; Mizoguchi, Tetsu; Eisawa, Hiroshi; Sugiyama, Seigo; Kimura, Takeshi

    2012-05-23

    To evaluate the relation of symptom onset to balloon time and door to balloon time with long term clinical outcome in patients with ST segment elevation myocardial infarction (STEMI) having primary percutaneous coronary intervention. Observation of large cohort of patients with acute myocardial infarction. 26 tertiary hospitals in Japan. 3391 patients with STEMI who had primary percutaneous coronary intervention within 24 hours of symptom onset. Composite of death and congestive heart failure, compared by onset to balloon time and door to balloon time. Compared with an onset to balloon time greater than 3 hours, a time of less than 3 hours was associated with a lower incidence of a composite of death and congestive heart failure (13.5% (123/964) v 19.2% (429/2427), P<0.001; relative risk reduction 29.7%). After adjustment for confounders, a short onset to balloon time was independently associated with a lower risk of the composite endpoint (adjusted hazard ratio 0.70, 95% confidence interval 0.56 to 0.88; P=0.002). However, no significant difference was found in the incidence of a composite of death and congestive heart failure between the two groups of patients with short (≤90 minutes) and long (>90 minutes) door to balloon time (16.7% (270/1671) v 18.4% (282/1720), P=0.54; relative risk reduction 9.2%). After adjustment for confounders, no significant difference was seen in the risk of the composite endpoint between the two groups of patients with short and long door to balloon time (adjusted hazard ratio: 0.98, 0.78 to 1.24: P=0.87). A door to balloon time of less than 90 minutes was associated with a lower incidence of a composite of death and congestive heart failure in patients who presented within 2 hours of symptom onset (11.9% (74/883) v 18.1% (147/655), P=0.01; relative risk reduction 34.3%) but not in patients who presented later (19.7% (196/788) v 18.7% (135/1065), P=0.44; -5.3%). Short door to balloon time was independently associated with a lower

  16. 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.

  17. Long-term Ecosystem Experiments, Data Assimilation, and Meta-Analysis

    NASA Astrophysics Data System (ADS)

    Hungate, B. A.; Van Groenigen, K. J.; Osenberg, C. W.; van Gestel, N.

    2015-12-01

    Land ecosystems affect climate and the atmosphere, and climate and atmospheric change affects ecosystems. Syntheses of ecosystem experiments investigating their responses to environmental change holds promise for understanding how to model these interactions, and thereby gain insight into Earth's future biosphere, atmosphere, and climate. Long-term experiments examining ecosystem responses are thought to be especially important in this effort, for their potential to reveal cumulative and progressive effects, subtle effects initially undetectable experimentally, but manifest more clearly over time, often with stronger implications for modeled responses than the more dramatic, short-term experimental responses. Here, we present new analyses of long-term experiments manipulating temperature, CO2 concentration, and precipitation, testing the general hypothesis that there are common temporal patterns of responses that reveal general biogeochemical characterizing ecosystem responses to these environmental changes. For example, we show that increased carbon input with elevated CO2 stimulates emissions of nitrous oxide and methane, important greenhouse gases, and that effects show no signs of diminishing over the duration of experiments that have documented responses. At the same time, we show that the temporal resolution for this response is limited, pointing to a potential limitation in the ability of experiments to address clearly long-term hypotheses. We also show that warming tends to have limited cumulative effects on total soil carbon stocks in long-term experiments, and explore the mechanisms underlying this response. Finally, we discuss the implications of these findings for models used to simulate long-term ecosystem responses to these environmental forcings, as well as the implications of these findings for the next generation of terrestrial ecosystem experiments.

  18. Influence of tree internal nitrogen reserves on the response of beech (Fagus sylvatica) trees to elevated atmospheric carbon dioxide concentration.

    PubMed

    Dyckmans, Jens; Flessa, Heiner

    2002-01-01

    We examined the influence of plant internal nitrogen (N) reserves on the response of 3-year-old beech (Fagus sylvatica L.) trees to elevated atmospheric CO2 concentration ([CO2]) in a dual 15N and 13C long-term labeling experiment. Trees were grown on sand and received either no N nutrition (-N treatment) or 4 mM N (+N treatment) for 1 year. The -N and +N pretreated trees were then placed in growth chambers and grown in 350 (ambient) or 700 ppm (elevated) of a 13CO2 atmosphere for 24 weeks. In all treatments, trees were supplied with 4 mM 15N during the experiment. Irrespective of tree N reserves, elevated [CO2] increased cumulative carbon (C) uptake by about 30% at Week 24 compared with that for trees in the ambient treatment. Elevated [CO2] also caused a shift in C allocation to belowground compartments, which was more pronounced in -N trees than in +N trees. In +N trees, belowground allocation of new C at Week 24 was 67% in ambient [CO2] compared with 70% in elevated [CO2]. The corresponding values for -N trees were 70 and 79%. The increase in C allocation in response to elevated [CO2] was most evident as an increase in belowground respiration; however, specific root respiration was unaffected by the CO2 or N treatments. Although elevated [CO2] increased root growth and belowground respiration, it had no effect on N uptake at Week 24. As a result of increased C uptake, N concentrations were decreased in trees in the elevated [CO2] treatment compared with trees in the ambient treatment in both N treatments. Partitioning of new N uptake was unaffected by elevated [CO2] in +N trees. In -N trees, however, N allocation to the stem decreased in response to elevated [CO2] and N allocation to fine roots increased, suggesting a reduction in the formation of N reserves in response to elevated [CO2]. We conclude that the response of beech trees to elevated [CO2] is affected by internal N status and that elevated [CO2] may influence the ability of the trees to form N

  19. Long-term oxygen therapy.

    PubMed

    Christopher, Kent L; Porte, Phillip

    2011-02-01

    This article provides an overview of the status of long-term oxygen therapy (LTOT). In the United States, payment cutbacks are occurring as a result of congressionally mandated competitive bidding and capped rental programs. These Medicare programs are discussed. These legislative and regulatory changes may result in reduced patient access to appropriate oxygen-delivery systems that meet medical needs, including optimal ambulation. Prescribing LTOT is addressed in this article, as is the need for adequate patient education. The importance of appropriate monitoring and reassessment is presented. The use of an LTOT collaborative care model is discussed. Although the new intermittent flow oxygen-delivery systems have potential benefits, there is consensus that each patient should be tested on the specific device because of variability in delivery and patient response. Feasible locations for patient education and monitoring are identified.

  20. Elevated BDNF protein level in cortex but not in hippocampus of MDMA-treated Dark Agouti rats: a potential link to the long-term recovery of serotonergic axons.

    PubMed

    Adori, Csaba; Andó, Rómeó D; Ferrington, Linda; Szekeres, Mária; Vas, Szilvia; Kelly, Paul A T; Hunyady, László; Bagdy, György

    2010-07-05

    3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") is a widely used recreational drug known to cause selective long-term serotonergic damage. In this study, we examined the pattern of BDNF protein expression 1 day, 3, 8, 12 and 24 weeks after a single 15mg/kg i.p. dose of MDMA to adolescent Dark Agouti rats. In parallel, we measured either tryptophan-hydroxylase immunoreactive (TpH IR) axon density, or [(3)H]-paroxetine-binding in parietal cortex and hippocampus, two brain areas known to have different recovery capacity after MDMA, to test whether BDNF-levels were associated with the long-term recovery of serotonergic fibers after a neurotoxic dose of MDMA. Both TpH IR axon density and [(3)H]-paroxetine-binding were significantly decreased 3 weeks after the treatment in both brain areas but while normalization in both parameters was found in parietal cortex 24 weeks after treatment, significant decreases remained evident in the hippocampus. In the parietal cortex, a significant reduction in BDNF protein levels was found in the acute phase after treatment (1 day), which was followed by a robust increase 8 weeks later and a return to control levels by 12 weeks. In contrast, no significant alteration of BDNF protein level was found in the hippocampus at any time points. This absence of any significant increase in BDNF protein levels in the hippocampus, and the persistence in this region of decreases in TpH IR axon density and [(3)H]-paroxetine-binding, raises the possibility that BDNF has an important role in the long-term recovery of serotonergic axons after MDMA treatment.

  1. Climate Predictability and Long Term Memory

    NASA Astrophysics Data System (ADS)

    Zhu, X.; Blender, R.; Fraedrich, K.; Liu, Z.

    2010-09-01

    The benefit of climate Long Term Memory (LTM) for long term prediction is assessed using data from a millennium control simulation with the atmosphere ocean general circulation model ECHAM5/MPIOM. The forecast skills are evaluated for surface temperature time series at individual grid points. LTM is characterised by the Hurst exponent in the power-law scaling of the fluctuation function which is determined by detrended fluctuation analysis (DFA). LTM with a Hurst exponent close to 0.9 occurs mainly in high latitude oceans, which are also characterized by high potential predictability. Climate predictability is diagnosed in terms of potentially predictable variance fractions. Explicit prediction experiments for various time steps are conducted on a grid point basis using an auto-correlation (AR1) predictor: in regions with LTM, prediction skills are beyond that expected from red noise persistence; exceptions occur in some areas in the southern oceans and over the northern hemisphere continents. Extending the predictability analysis to the fully forced simulation shows large improvement in prediction skills.

  2. Effects of long-term (10 years) exposure to elevated CO2 and O3 on trembling Aspen carbon and nitrogen metabolism at the aspen FACE (Free-Air Carbon Dioxide Enrichment) study site

    Treesearch

    Rakesh Minocha; Stephanie Long; Subhash Minocha; Paula Marquardt; Neil Nelson; Mark. Kubiske

    2010-01-01

    This study was conducted at the Aspen Free-Air Carbon Dioxide Enrichment (FACE) experimental site, Rhinelander, WI, (USA). Since 1998, 12 experimental rings planted in 1997 underwent four different treatments: control; elevated CO2 (560 ppm); elevated O3 (1.5X ambient) and elevated CO2 (560 ppm) + O...

  3. The impact of the location of a chronic total occlusion in a non-infarct-related artery on long-term mortality in ST-elevation myocardial infarction patients.

    PubMed

    Hoebers, Loes P C; Elias, Joëlle; van Dongen, Ivo M; Ouweneel, Dagmar M; Claessen, Bimmer E P M; Piek, Jan J; Henriques, Jose P S

    2016-07-20

    Several studies have evaluated the impact of a CTO on short- and long-term mortality in STEMI patients. It has been speculated that the adverse effect on prognosis could differ per coronary location. The purpose of this study was to evaluate whether the long-term prognosis of STEMI patients differs according to the coronary location of the CTO. Between 2000 and 2012, a total of 480 STEMI patients with a CTO in a non-infarct-related artery were included. The primary outcome for the present analysis was three-year all-cause mortality, evaluating the impact of the coronary CTO and infarct location. Four hundred and thirteen patients had a single CTO in a non-infarct-related artery, whereas 67 patients had more than one CTO and in this group mortality was higher. In patients with a single CTO, the highest risk of mortality was observed when the culprit lesion was located in the LAD or proximal LCX or when the CTO lesion was located in the proximal LAD. We previously reported that STEMI patients with a CTO have a worse prognosis than STEMI patients without a CTO. We now show that, in these patients, LAD or proximal LCX location for the culprit lesion, or proximal LAD location for the CTO lesion, is associated with the highest risk. As a result, almost all CTO patients are at increased risk for mortality due to the combination of the culprit and CTO artery location.

  4. Asthma Medicines: Long-Term Control

    MedlinePlus

    ... Size Email Print Share Asthma Medicines: Long-term Control Page Content Article Body Corticosteroids Synthetic versions of ... form, they are used exclusively for long-term control; they are not very effective for acute symptoms. ...

  5. Consumer Direction in Long-Term Care.

    ERIC Educational Resources Information Center

    Generations, 2000

    2000-01-01

    Issue includes 17 theme articles on long-term care, covering legal issues, federal role, state programs, demonstration programs, family caregivers, home health care, home care workers, culturally appropriate long-term care, financial support, and cognitive impairments. (SK)

  6. Long-term cardiovascular mortality after procedure-related or spontaneous myocardial infarction in patients with non-ST-segment elevation acute coronary syndrome: a collaborative analysis of individual patient data from the FRISC II, ICTUS, and RITA-3 trials (FIR).

    PubMed

    Damman, Peter; Wallentin, Lars; Fox, Keith A A; Windhausen, Fons; Hirsch, Alexander; Clayton, Tim; Pocock, Stuart J; Lagerqvist, Bo; Tijssen, Jan G P; de Winter, Robbert J

    2012-01-31

    The present study was designed to investigate the long-term prognostic impact of procedure-related and spontaneous myocardial infarction (MI) on cardiovascular mortality in patients with non-ST-elevation acute coronary syndrome. Five-year follow-up after procedure-related or spontaneous MI was investigated in the individual patient pooled data set of the FRISC-II (Fast Revascularization During Instability in Coronary Artery Disease), ICTUS (Invasive Versus Conservative Treatment in Unstable Coronary Syndromes), and RITA-3 (Randomized Intervention Trial of Unstable Angina 3) non-ST-elevation acute coronary syndrome trials. The principal outcome was cardiovascular death up to 5 years of follow-up. Cumulative event rates were estimated by the Kaplan-Meier method; hazard ratios were calculated with time-dependent Cox proportional hazards models. Adjustments were made for the variables associated with long-term outcomes. Among the 5467 patients, 212 experienced a procedure-related MI within 6 months after enrollment. A spontaneous MI occurred in 236 patients within 6 months. The cumulative cardiovascular death rate was 5.2% in patients who had a procedure-related MI, comparable to that for patients without a procedure-related MI (hazard ratio 0.66; 95% confidence interval, 0.36-1.20, P=0.17). In patients who had a spontaneous MI within 6 months, the cumulative cardiovascular death rate was 22.2%, higher than for patients without a spontaneous MI (hazard ratio 4.52; 95% confidence interval, 3.37-6.06, P<0.001). These hazard ratios did not change materially after risk adjustments. Five-year follow-up of patients with non-ST-elevation acute coronary syndrome from the 3 trials showed no association between a procedure-related MI and long-term cardiovascular mortality. In contrast, there was a substantial increase in long-term mortality after a spontaneous MI.

  7. 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.

  8. AB055. Long term NIV

    PubMed Central

    Siopi, Dimitra

    2016-01-01

    During the last decades, non-invasive mechanical ventilation has evolved into one of the most evidence-based areas of respiratory medicine, with many indications in acute or chronic respiratory failure. From the first application of negative pressure models during poliomyelitis epidemics to the new sophisticated positive pressure models, and the development of the “intelligent ventilators”, there has been a long time course. Undoubtedly the spur was given by better understanding of respiratory physiology during sleep and the shift of healthcare towards a chronic base. Novel randomized controlled trials (RCTs) established the use of NIV in acute respiratory failure due to exacerbations of COPD, as well as acute pulmonary edema and weaning from invasive mechanical ventilation. Long-term NIV has been used in neuromuscular diseases for many decades, first in Duchenne muscular dystrophy, and then spreading to other disorders of this category, increasing survival in inherited neuromuscular diseases. NIV should be initiated early in the course of the disease, when symptomatic nocturnal hypoventilation is detected. Combined with cough augmentation (physiotherapy, insufflation-exsufflation devices) and percutaneous gastrostomy feeding, it can delay tracheostomy and invasive ventilation. In ALS patients NIV improves the quality of life and increases survival, especially when there is no bulbar involvement. The right time to initiate ventilation in this group of patients is not well established since it is difficult to detect signs and symptom of respiratory impairment. Patients seem to benefit from an early application of NIV, and their personal decisions should always be considered before any intervention. In patients with chest wall disorders NIV—despite the fact that RCTs are lacking—has proved its value in many uncontrolled trials and numerous reports. It seems to improve the work of breathing, sleep architecture, nocturnal and daytime arterial blood gases. The

  9. 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.

  10. Long-term corrosion studies

    SciTech Connect

    Gdowski, G.

    1998-05-29

    The scope of this activity is to assess the long-term corrosion properties of metallic materials under consideration for fabricating waste package containers. Three classes of metals are to be assessed: corrosion resistant, intermediate corrosion resistant, and corrosion allowance. Corrosion properties to be evaluated are general, pitting and crevice corrosion, stress-corrosion cracking, and galvanic corrosion. The performance of these materials will be investigated under conditions that are considered relevant to the potential emplacement site. Testing in four aqueous solutions, and vapor phases above them, and at two temperatures are planned for this activity. (The environmental conditions, test metals, and matrix are described in detail in Section 3.0.) The purpose and objective of this activity is to obtain the kinetic and mechanistic information on degradation of metallic alloys currently being considered for waste package containers. This information will be used to provide assistance to (1) waste package design (metal barrier selection) (E-20-90 to E-20-92), (2) waste package performance assessment activities (SIP-PA-2), (3) model development (E-20-75 to E-20-89). and (4) repository license application.

  11. Long-Term Planning in Higher Education.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific and Cultural Organization, Bangkok (Thailand). Principal Regional Office for Asia and the Pacific.

    This report presents the concepts and issues discussed at a Regional Symposium on Long-term Planning in Higher Education held in Dhaka, Bangladesh, September 21-30, 1986. Chapter 1 explores some fundamental issues about the rationale for the objectives of long-term planning. It defines long-term planning in higher education, considers its…

  12. Long Term TOA - M Data and Information

    Atmospheric Science Data Center

    2015-06-30

    A Long-Term TOA and Constrained Surface Radiation Budget Project A Long-Term TOA and Constrained Surface Readiation Budget Dataset Using Merged CERES, ... and apply the knowledge to existing data to develop long-term (nearly 30 years) consistent and calibrated data product (TOA irradiances ...

  13. 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.

  14. Impact of stent overlapping on long-term clinical outcomes in patients with ST-segment elevation myocardial infarction: insights from the five-year follow-up of the EXAMINATION trial.

    PubMed

    Ortega-Paz, Luis; Brugaletta, Salvatore; Giacchi, Giuseppe; Ishida, Kohki; Cequier, Angel; Iñiguez, Andrés; Serra, Antonio; Jiménez-Quevedo, Pilar; Mainar, Vicente; Campo, Gianluca; Tespili, Maurizio; den Heijer, Peter; Valgimigli, Marco; Serruys, Patrick W; Sabaté, Manel

    2017-08-04

    The aim of this study was to compare the long-term outcomes of STEMI patients treated with overlap vs. no-overlap stents. We analysed the one- and five-year clinical outcomes of 1,498 STEMI patients according to overlapping stent implantation. The primary endpoint was a patient-oriented composite endpoint (PoCE) of all-cause death, myocardial infarction, and repeat revascularisation. Stent thrombosis data were also analysed. Four hundred and four (27.0%) patients were treated with overlapping stents, whereas the remaining 1,094 (73.0%) were not. At one and five years, there was no difference in PoCE between the overlap vs. no-overlap group, even after adjustment (14.9% vs. 12.4%; HR 1.20, 95% CI: 0.76-1.90; p=0.44, and 26.3% vs. 22.3%; HR 1.14, 95% CI: 0.80-1.62; p=0.47, respectively). At five years, within the overlap group, patients who received BMS had a trend towards a higher rate of PoCE and DoCE as compared to those who received EES. At one year, there was a trend towards a higher rate of definite/probable stent thrombosis in the overlap compared to the no-overlap group (2.2% vs. 1.6%; HR 2.35, 95% CI: 0.95-5.90; p=0.06). This difference was driven by a higher rate for BMS compared to EES (4.4% vs. 0%, p for interaction=0.03) in the overlap group. At five years, the absolute risk difference for overlap (3.5% vs. 2.2%, p=0.99) and interaction for BMS (p=0.03) were similar. In patients presenting with STEMI, the long-term PoCE was similar for the overlap and no-overlap groups. Overlap among patients receiving BMS appears to be associated with a higher risk for adverse cardiovascular outcomes and stent thrombosis.

  15. Simulation of recurring earthquakes along the Nankai trough and their relationship to the Tokai long-term slow slip events taking into account the effect of locally elevated pore pressure and subducting ridges

    NASA Astrophysics Data System (ADS)

    Hirose, Fuyuki; Maeda, Kenji

    2013-08-01

    earthquakes of moment magnitudes greater than 8 associated with subduction of the Philippine Sea plate under Japan have occurred along the Nankai trough with a recurrence interval of 90-150 years. A large-scale rupture of the Tokai fault segment is believed to be imminent because that segment did not rupture during the most recent Tonankai earthquake in 1944. Recurring long-term slow slip events (LSSEs) have recently been observed in the Tokai region. To investigate the current stress state in the Tokai region, we numerically simulated earthquake cycles using a three-dimensional model consisting of triangular cells based on the rate- and state-dependent friction law. Our numerical simulations successfully modeled the Tokai segment not ruptured during the 1944 Tonankai earthquake as well as the recurring LSSEs in the Tokai region. We found that a large characteristic displacement (L) and effective normal stress (σ) in areas of subducted ridges are essential to avoid rupture of the Tokai segment during the 1944 Tonankai earthquake. We also demonstrated that we can reproduce the recurring LSSEs by assigning low values of σ and L to the area beneath Lake Hamana without introducing a velocity-strengthening friction law at high slip rate. Our simulation showed that the amplitudes of the LSSEs increased following the earthquakes that did not rupture the Tokai segment, which suggests that the recent LSSEs may be related to the accumulation of stresses in the Tokai segment because it did not rupture during the 1944 earthquake.

  16. Relation of Post-Coronary Artery Bypass Graft Creatine Kinase-MB Elevations and New Q Waves With Long-Term Cardiovascular Death in Patients With Diabetes Mellitus and Multivessel Coronary Artery Disease.

    PubMed

    Domanski, Michael; Farkouh, Michael E; Zak, Victor; French, John; Alexander, John H; Bochenek, Andrzej; Hamon, Martial; Mahaffey, Kenneth; Puskas, John; Smith, Peter; Shrader, Peter; Fuster, Valentin

    2016-12-01

    Associations of early creatine phosphokinase-MB (CK-MB) elevation and new Q waves and their association with cardiovascular death (CVD) after coronary artery bypass grafting (CABG) have been reported, but this association has not been studied in a large population of patients with diabetes mellitus. In this study, we examine the association of periprocedural CK-MB elevations and new Q waves with CVD in the Future Revascularization Evaluation in Patients with Diabetes Mellitus: Optimal Management of Multivessel Disease trial. Cox proportional hazards regression was used to assess the relation of CK-MB elevations and new Q waves in the first 24 hours after procedure and their relation to CVD; logistic regression was used to assess odds ratios of these variables. Hazard ratios, 95% confidence intervals, and p values associated with Wald chi-square test are reported. CK-MB elevation in first 24 hours after procedure was independently associated with CVD. CVD hazard increased by 6% (p <0.001) with each multiple of CK-MB above the upper reference limit (URL); odds of new post-CABG Q waves increased by a factor of 1.08 (p <0.001); at 7× CK-MB URL, HR was >2. CK-MB URL multiples of 7, 12, and 15 were associated with new Q-wave odds ratios of 9, 16, and 27 times, respectively (p ≤0.001, C-statistic >0.70). New Q waves were independently associated with survival in the multivariate model only when CK-MB was excluded (p = 0.01). In conclusion, independent associations included (1) CVD and early post-CABG CK-MB elevation; (2) new Q waves with early post-CABG CK-MB elevation; (3) CVD with new Q waves only when CK-MB elevation is excluded from analysis.

  17. 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.

  18. [Perspectives in long-term care insurance].

    PubMed

    Pick, P

    2007-03-01

    Twelve years after its introduction, long-term care insurance is back on the agenda and up for political reform. This paper shows why long-term care insurance needs to be reformed. The two central aspects on which reform projects focus are addressed: firstly, the structural improvement of nursing care and long-term care insurance and, secondly, the creation of a sustained financing. The principal conclusion is that, while there is a broad consensus about the structural improvement of long-term care insurance, opinions differ widely in the matter of its sustained financing. As a consequence, a coherent financing concept has yet to emerge.

  19. Acclimation of leaf hydraulic conductance and stomatal conductance of Pinus taeda (loblolly pine) to long-term growth in elevated CO2 (free-air CO2 enrichment) and N-fertilizationpce

    Treesearch

    Jean-Christophe Domec; Sari Palmroth; Eric Ward; Chris Maier; M. Therezien; Ram Oren

    2009-01-01

    We investigated how leaf hydraulic conductance (Kleaf) of loblolly pine trees is influenced by soil nitrogen amendment (N) in stands subjected to ambient or elevated CO2 concentrations CO2 a and CO2 e, respectively). We also examined how Kleaf varies with changes in reference leaf water potential (...

  20. A reduced fraction of plant N derived from atmospheric N (%Ndfa) and reduced rhizobial nifH gene numbers indicate a lower capacity for nitrogen fixation in nodules of white clover exposed to long-term CO2 enrichment

    NASA Astrophysics Data System (ADS)

    Watanabe, T.; Bowatte, S.; Newton, P. C. D.

    2013-06-01

    Using the δ15N natural abundance method, we found that the fraction of nitrogen derived from atmospheric N (%Ndfa) in field grown white clover (Trifolium repens L.) plants was significantly lower (72.0% vs. 89.5%, p = 0.047 in a grassland exposed to elevated CO2 for 13 yr using Free Air Carbon Dioxide Enrichment (FACE). Twelve months later we conducted an experiment to investigate the reasons behind the reduced N fixation. We took cuttings from white clover plants growing in the FACE and established individual plants in a glasshouse using soil from the appropriate ambient or elevated CO2 treatments. The established plants were then transplanted back into their "rings of origin" and sampled over a 6 week period. We used molecular ecological analyses targeting nifH genes and transcripts of rhizobia in symbiosis with white clover (Trifolium repens L.) to understand the potential mechanisms. Shoot biomass was significantly lower in eCO2 but there was no difference in nodule number or mass per plant. The numbers of nifH genes and gene transcripts per nodule were significantly reduced under eCO2 but the ratio of gene to transcript number and the strains of rhizobia present were the same in both treatments. We conclude that the capacity for biological nitrogen fixation was reduced by eCO2 in white clover and was related to the reduced rhizobia numbers in nodules. We discuss the finding of reduced gene number in relation to factors controlling bacteroid DNA amount which may imply an influence of nitrogen as well as phosphorus.

  1. A reduced fraction of plant N derived from atmospheric N (%Ndfa) and reduced rhizobial nifH gene numbers indicate a lower capacity for nitrogen fixation in nodules of white clover exposed to long-term CO2 enrichment

    NASA Astrophysics Data System (ADS)

    Watanabe, T.; Bowatte, S.; Newton, P. C. D.

    2013-12-01

    Using the δ15N natural abundance method, we found that the fraction of nitrogen derived from atmospheric N (%Ndfa) in field-grown white clover (Trifolium repens L.) plants was significantly lower (72.0% vs. 89.8%, p = 0.047 in a grassland exposed to elevated CO2 for 13 yr using free air carbon dioxide enrichment (FACE). Twelve months later we conducted an experiment to investigate the reasons behind the reduced N fixation. We took cuttings from white clover plants growing in the FACE and established individual plants in a glasshouse using soil from the appropriate ambient or elevated CO2 treatments. The established plants were then transplanted back into their "rings of origin" and sampled over a 6-week period. We used molecular ecological analyses targeting nifH genes and transcripts of rhizobia in symbiosis with white clover (Trifolium repens L.) to understand the potential mechanisms. Shoot biomass was significantly lower in eCO2, but there was no difference in nodule number or mass per plant. The numbers of nifH genes and gene transcripts per nodule were significantly reduced under eCO2, but the ratio of gene to transcript number and the strains of rhizobia present were the same in both treatments. We conclude that the capacity for biological nitrogen fixation was reduced by eCO2 in white clover and was related to the reduced rhizobia numbers in nodules. We discuss the finding of reduced gene number in relation to factors controlling bacteroid DNA amount, which may imply an influence of nitrogen as well as phosphorus.

  2. Wnt signaling is required for long-term memory formation

    PubMed Central

    Tan, Ying; Yu, Dinghui; Busto, Germain U.; Wilson, Curtis; Davis, Ronald L.

    2013-01-01

    SUMMARY Wnt signaling regulates synaptic plasticity and neurogenesis in the adult nervous system, suggesting a potential role in behavioral processes. Here, we probed the requirement for Wnt signaling during olfactory memory formation in Drosophila using an inducible RNA interference approach. Interfering with β-catenin expression in the adult mushroom body neurons specifically impaired long-term memory without altering short-term memory. The impairment was reversible, rescued with expression of a wild-type β-catenin transgene, and correlated with a disruption of a cellular long-term memory trace. Inhibition of wingless, a Wnt ligand, and arrow, a Wnt co-receptor, also impaired long-term memory. Wingless expression in wild type flies was transiently elevated in the brain after long-term memory conditioning. Thus, inhibiting three key components of the Wnt signaling pathway in the adult mushroom bodies impairs long-term memory, collectively indicating that this pathway mechanistically underlies this specific form of memory. PMID:24035392

  3. Long-term Variability of Beach Cusps

    NASA Astrophysics Data System (ADS)

    Pianca, C.; Holman, R. A.; Siegle, E.

    2016-02-01

    The most curious morphological features observed on beaches are the cusps. Due to their rhythmic spacing, beach cusps have attracted many observers and many, often contradictory, theories as to their form. Moreover, most of the research about beach cusps has focused on their formation. Few had available long time series to study such things as the variability of alongshore and cross-shore position and spacing on the cusp field, the presence, longevity and interactions between higher and lower sets of cusps, and the processes by which cusp fields extend, shrink or change length scale. The purpose of this work is to use long-term data sets of video images from two study sites, an intermediate (Duck, USA, 26 years) and a reflective beach (Massaguaçu, Brazil, 3 years), to investigate the temporal and spatial changes of cusps conditions. Time-evolving shoreline data were first extracted using an algorithm called ASLIM (Pianca et al 2015). Cusps were then identified based on the band-passed variability of time exposure image data about this shoreline as a function of elevation relative to MSL. The identified beaches cusps will be analyzed for cusp spacing, positions (upper or lower cusps), alongshore variability, merging events, percentage of cusp events, patterns of the events and time scales of variability. Finally, the relationship of these characteristics to environmental conditions (wave, tides, beach conditions) will be studied.

  4. Long-term treatment outcome in acromegaly.

    PubMed

    Holdaway, I M; Rajasoorya, C R; Gamble, G D; Stewart, A W

    2003-08-01

    A number of groups have developed guidelines to indicate whether an individual with acromegaly has been cured by treatment. However, studies to date do not provide a robust definition of biochemical remission of the disorder based on correlation with long-term outcome. Available data suggest that those with a random serum growth hormone (GH) level of <2.5 microg/l, or a glucose-suppressed GH level of <1 microg/l following treatment have mortality figures indistinguishable from the general population. However, the confidence limits for these mortality estimates are quite wide. It remains possible that growth hormone levels lower than 1 microg/l for random samples, or even lower when using ultrasensitive GH assays, may indicate superior outcome, but this remains to be confirmed. There are limited data relating serum insulin-like growth factor-I (IGF-I) levels to outcome, although normalisation of serum IGF-I clearly improves outcome compared with continued elevation of measurements after treatment. Current evidence suggests that a post-treatment random serum GH <2.5 microg/l and a normal serum IGF-I value defines biochemical cure. Available data suggest that achieving similar growth hormone levels after treatment also reduces the prevalence of chronic complications of the disorder, which is subsequently reflected in improved mortality.

  5. 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…

  6. 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…

  7. 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…

  8. 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.

  9. Long-Term Nutrition: A Clinician's Guide to Successful Long-Term Enteral Access in Adults.

    PubMed

    Bechtold, Matthew L; Mir, Fazia A; Boumitri, Christine; Palmer, Lena B; Evans, David C; Kiraly, Laszlo N; Nguyen, Douglas L

    2016-09-22

    Long-term nutrition support requires long-term enteral access. To ensure the success of long-term enteral access, many factors need to be taken into consideration. This article represents a guide to placing and maintaining access in patients requiring long-term nutrition and addresses many of the common questions regarding long-term enteral access, such as indications, types of access, feeding after access placed, and recognition and treatment of potential complications. This guide will help the clinician establish and maintain access to maximize nutrition in patients requiring long-term nutrition.

  10. 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.

  11. 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

  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. 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.

  14. [Influence of elevated atmospheric CO2 on rhizosphere microbes and arbuscular mycorrhizae].

    PubMed

    Chen, Jing; Chen, Xin; Tang, Jianjun

    2004-12-01

    The changes of microbial communities in rhizosphere and the formation of mycorrhizae play an important role in affecting the dynamics of plant communities and terrestrial ecosystems. This paper summarized and discussed the effects of elevated atmospheric CO2 on them. Under elevated atmospheric CO2, the carbohydrates accumulated in root systems increased, and the rhizospheric environment and its microbial communities as well as the formation of mycorrhizae changed. It is suggested that the researches in the future should be focused on the effects of rhizosphere microbes and arbuscular mycorrhizae on regulating the carbon dynamics of plant communities and terrestrial ecosystems under elevated atmospheric CO2.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. Long-term elevated air [CO2 ] strengthens photosynthetic functioning and mitigates the impact of supra-optimal temperatures in tropical Coffea arabica and C. canephora species.

    PubMed

    Rodrigues, Weverton P; Martins, Madlles Q; Fortunato, Ana S; Rodrigues, Ana P; Semedo, José N; Simões-Costa, Maria C; Pais, Isabel P; Leitão, António E; Colwell, Filipe; Goulao, Luis; Máguas, Cristina; Maia, Rodrigo; Partelli, Fábio L; Campostrini, Eliemar; Scotti-Campos, Paula; Ribeiro-Barros, Ana I; Lidon, Fernando C; DaMatta, Fábio M; Ramalho, José C

    2016-01-01

    The tropical coffee crop has been predicted to be threatened by future climate changes and global warming. However, the real biological effects of such changes remain unknown. Therefore, this work aims to link the physiological and biochemical responses of photosynthesis to elevated air [CO2 ] and temperature in cultivated genotypes of Coffea arabica L. (cv. Icatu and IPR108) and Coffea canephora cv. Conilon CL153. Plants were grown for ca. 10 months at 25/20°C (day/night) and 380 or 700 μl CO2 l(-1) and then subjected to temperature increase (0.5°C day(-1) ) to 42/34°C. Leaf impacts related to stomatal traits, gas exchanges, C isotope composition, fluorescence parameters, thylakoid electron transport and enzyme activities were assessed at 25/20, 31/25, 37/30 and 42/34°C. The results showed that (1) both species were remarkably heat tolerant up to 37/30°C, but at 42/34°C a threshold for irreversible nonstomatal deleterious effects was reached. Impairments were greater in C. arabica (especially in Icatu) and under normal [CO2 ]. Photosystems and thylakoid electron transport were shown to be quite heat tolerant, contrasting to the enzymes related to energy metabolism, including RuBisCO, which were the most sensitive components. (2) Significant stomatal trait modifications were promoted almost exclusively by temperature and were species dependent. Elevated [CO2 ], (3) strongly mitigated the impact of temperature on both species, particularly at 42/34°C, modifying the response to supra-optimal temperatures, (4) promoted higher water-use efficiency under moderately higher temperature (31/25°C) and (5) did not provoke photosynthetic downregulation. Instead, enhancements in [CO2 ] strengthened photosynthetic photochemical efficiency, energy use and biochemical functioning at all temperatures. Our novel findings demonstrate a relevant heat resilience of coffee species and that elevated [CO2 ] remarkably mitigated the impact of heat on coffee physiology, therefore

  20. Long-term evaluation of osseointegrated implants placed in sites augmented with sinus floor elevation associated with vertical ridge augmentation: a retrospective study of 38 consecutive implants with 1- to 7-year follow-up.

    PubMed

    Simion, Massimo; Fontana, Filippo; Rasperini, Giulio; Maiorana, Carlo

    2004-06-01

    This clinical study retrospectively evaluated, after 1 to 7 years of prosthetic loading, 38 implants consecutively placed in 16 surgical sites, where severe atrophy of the posterior maxilla was treated by combining sinus elevation with the vertical ridge regenerative procedure. Two different surgical techniques were adopted. In seven patients (16 implants), implants were placed at the same stage as the regenerative procedures. In the other seven patients (22 implants), implant placement was performed at second-stage surgery, after 6 to 13 months of submerged membrane healing. Each implant was classified as a success, survival, or failure. The distance between the top of the implant shoulder and the first visible bone-implant contact was assessed radiographically for every implant at the mesial and distal sides. Two membranes became exposed during the healing process (12.5%). In the remaining 14 sites (87.5%), the membrane remained covered for a 6- to 13-month healing period. The survival rate of the implants was 92.1%, whereas the success rate was 76.3%. Three implants (7.9%) failed. A comparison of the implant shoulder-bone-implant contact distances between abutment connection and the last examination showed a mean crestal loss of 1.65 mm at the mesial side and 1.68 mm at the distal side. The bone regenerated vertically by means of sinus floor elevation and vertical ridge augmentation showed the same biologic behavior as native, nonregenerated bone; however, in a few cases, its remodeling pattern seemed to determine slightly higher bone crest resorption.

  1. Long-term nitrogen regulation of forest carbon sequestration

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Luo, Y.

    2009-12-01

    It is well established that nitrogen (N) limits plant production but unclear how N regulates long-term terrestrial carbon (C) sequestration in response to rising atmospheric C dioxide (CO2)(Luo et al., 2004). Most experimental evidence on C-N interactions is primarily derived from short-term CO2 manipulative studies (e.g. Oren et al., 2001; Reich et al., 2006a), which abruptly increase C inputs into ecosystems and N demand from soil while atmospheric CO2 concentration in the real world is gradually increasing over time (Luo & Reynolds, 1999). It is essential to examine long-term N regulations of C sequestration in natural ecosystems. Here we present results of a synthesis of more than 100 studies on long-term C-N interactions during secondary succession. C significantly accumulates in plant, litter and forest floor in most studies, and in mineral soil in one-third studies during stand development. Substantial increases in C stock are tightly coupled with N accretion. The C: N ratio in plant increases with stand age in most cases, but remains relatively constant in litter, forest floor and mineral soil. Our results suggest that natural ecosystems could have the intrinsic capacity to maintain long-term C sequestration through external N accrual, high N use efficiency, and efficient internal N cycling.

  2. [Effects of elevated atmospheric CO2 on the exchange of trace gases between ecosystems and the atmosphere].

    PubMed

    Xu, Zhongjun; Zheng, Xunhua; Wang, Yuesi

    2002-10-01

    The latest researches on the effects of elevated atmospheric CO2 on the exchanges of trace gases (e.g., CO2, CH4 and N2O) between the atmosphere and ecosystems were reviewed. The techniques and methods involved in the researches were introduced firstly. Then the review mainly focused upon the results from those studies using the open-top-chamber (OTC) methods and the free-air carbon dioxide enrichment (FACE) system. Generally, elevated atmospheric CO2 may stimulate biomass accumulation, and enlarge C/N ratio in plant tissue so as to reduce the decomposition of organic matter. This action could increase CO2 sequestration in terrestrial ecosystems. Elevated atmospheric CO2 could impact on methanogenic bacteria and CH4 emissions. An increase in CH4 emissions from wetland may appear. The argument among the responses of N2O emissions to elevated CO2, however, was inconsistent. So far, no study on other trace gases was reported. More efforts should be taken in the research on the effects of elevated atmospheric CO2 on the exchange of trace gases.

  3. Hospital diversification into long-term care.

    PubMed

    Shah, A; Fennell, M; Mor, V

    2001-01-01

    In the 1990s, acute care hospitals in the United States encountered an unstable operating environment created by a series of transformations in the health care delivery system and long-term-care market. Confronted with an array of economic pressures and demographic changes, hospitals were motivated to engage in long-term-care diversification, such as establishing a long-term-care unit or providing home health services, as a means of entering new markets and ensuring financial stability. This article examines the organizational, market, and community factors associated with this strategic activity among a national sample of urban and rural hospitals.

  4. 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.

  5. 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).

  6. Acclimation of leaf hydraulic conductance and stomatal conductance of Pinus taeda (loblolly pine) to long-term growth in elevated CO(2) (free-air CO(2) enrichment) and N-fertilization.

    PubMed

    Domec, Jean-Christophe; Palmroth, Sari; Ward, Eric; Maier, Chris A; Thérézien, M; Oren, Ram

    2009-11-01

    We investigated how leaf hydraulic conductance (K(leaf)) of loblolly pine trees is influenced by soil nitrogen amendment (N) in stands subjected to ambient or elevated CO(2) concentrations (CO(2)(a) and CO(2)(e), respectively). We also examined how K(leaf) varies with changes in reference leaf water potential (Psi(leaf-ref)) and stomatal conductance (g(s-ref)) calculated at vapour pressure deficit, D of 1 kPa. We detected significant reductions in K(leaf) caused by N and CO(2)(e), but neither treatment affected pre-dawn or midday Psi(leaf). We also detected a significant CO(2)(e)-induced reduction in g(s-ref) and Psi(leaf-ref). Among treatments, the sensitivity of K(leaf) to Psi(leaf) was directly related to a reference K(leaf) (K(leaf-ref) computed at Psi(leaf-ref)). This liquid-phase response was reflected in a similar gas-phase response, with g(s) sensitivity to D proportional to g(s-ref). Because leaves represented a substantial component of the whole-tree conductance, reduction in K(leaf) under CO(2)(e) affected whole-tree water use by inducing a decline in g(s-ref). The consequences of the acclimation of leaves to the treatments were: (1) trees growing under CO(2)(e) controlled morning leaf water status less than CO(2)(a) trees resulting in a higher diurnal loss of K(leaf); (2) the effect of CO(2)(e) on g(s-ref) was manifested only during times of high soil moisture.

  7. 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, ...

  8. 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)

  9. Roadmap to Long-Term Monitoring Optimization

    EPA Pesticide Factsheets

    This roadmap focuses on optimization of established long-term monitoring programs for groundwater. Tools and techniques discussed concentrate on methods for optimizing the monitoring frequency and spatial (three-dimensional) distribution of wells ...

  10. Long-term-care legal update.

    PubMed

    Fiesta, J

    1998-04-01

    As more nurses move from the acute care setting to long-term-care and home health care, different practice issues arise. To maximize liability protection, nurses must understand the legal issues unique to each delivery system.

  11. Evidence-based long term care design.

    PubMed

    Calkins, Margaret P

    2009-01-01

    Research on the impact of the built environment in long-term care settings continues to grow. This article focuses on work conducted and published since 2000, when an earlier review on research on dementia and design was published. The vast majority of research that addressed neurological conditions in residents in long-term care settings (assisted living and nursing homes) relates to Alzheimer's disease and related dementias.

  12. Elevated Eocene atmospheric CO2 and its subsequent decline.

    PubMed

    Lowenstein, Tim K; Demicco, Robert V

    2006-09-29

    Quantification of the atmospheric concentration of CO2 ([CO2]atm) during warm periods of Earth's history is important because burning of fossil fuels may produce future [CO2]atm approaching 1000 parts per million by volume (ppm). The early Eocene (~56 to 49 million years ago) had the highest prolonged global temperatures of the past 65 million years. High Eocene [CO2]atm is established from sodium carbonate minerals formed in saline lakes and preserved in the Green River Formation, western United States. Coprecipitation of nahcolite (NaHCO3) and halite (NaCl) from surface waters in contact with the atmosphere indicates [CO2]atm > 1125 ppm (four times preindustrial concentrations), which confirms that high [CO2]atm coincided with Eocene warmth.

  13. Soil respiration in northern forests exposed to elevated atmospheric carbon dioxide and ozone

    Treesearch

    Kurt Pregitzer; Wendy Loya; Mark Kubiske; Donald Zak

    2006-01-01

    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)...

  14. 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.

  15. Long Term Outcomes after Pediatric Liver Transplantation

    PubMed Central

    2013-01-01

    Long term outcomes after liver transplantation are major determinants of quality of life and of the value of this heroic treatment. As short term outcomes are excellent, our community is turning to take a harder look at long term outcomes. The purpose of this paper is to review these outcomes, and highlight proposed treatments, as well as pressing topics needing to be studied. A systemic review of the English literature was carried in PubMed, covering all papers addressing long term outcomes in pediatric liver transplant from 2000-2013. Late outcomes after pediatric liver transplant affect the liver graft in the form of chronic liver dysfunction. The causes include rejection particularly humoral rejection, but also de novo autoimmune hepatitis, and recurrent disease. The metabolic syndrome is a major factor in long term cardiovascular complication risk. Secondary infections, kidney dysfunction and malignancy remain a reality of those patients. There is growing evidence of late cognitive and executive function delays affecting daily life productivity as well as likely adherence. Finally, despite a good health status, quality of life measures are comparable to those of children with chronic diseases. Long term outcomes are the new frontier in pediatric liver transplantation. Much is needed to improve graft survival, but also to avoid systemic morbidities from long term immunosuppression. Quality of life is a new inclusive measure that will require interventions and innovative approaches respectful not only on the patients but also of their social circle. PMID:24511516

  16. Short- and long-term climate changes on Mars

    NASA Technical Reports Server (NTRS)

    Pollack, James B.

    1992-01-01

    The present climate of Mars is dominated by the seasonal cycles of dust, water vapor, and carbon dioxide. Understanding these cycles represents a first step towards interpreting climate changes in the past. Past climates on Mars were probably different from the present one due to astronomical variations of orbital and axial properties, to major changes in atmospheric pressure and/or composition, and to long-term changes in solar luminosity.

  17. Eurasian snow depth in long-term climate reanalyses

    NASA Astrophysics Data System (ADS)

    Wegmann, Martin; Orsolini, Yvan; Dutra, Emanuel; Bulygina, Olga; Sterin, Alexander; Brönnimann, Stefan

    2017-04-01

    Snow cover variability has significant effects on local and global climate evolution. By changing surface energy fluxes and hydrological conditions, changes in snow cover can alter atmospheric circulation and lead to remote climate effects. To document such multi-scale climate effects, atmospheric reanalysis and derived products offer the opportunity to analyze snow variability in great detail far back to the early 20th century. So far only little is know about their quality. Comparing snow depth in four long-term reanalysis datasets with Russian in situ snow depth data, we find a moderately high daily correlation (around 0.6-0.7), which is comparable to correlations for the recent era (1981-2010), and a good representation of sub-decadal variability. However, the representation of pre-1950 inter-decadal snow variability is questionable, since reanalysis products divert towards different base states. Limited availability of independent long-term snow data makes it difficult to assess the exact cause for this bifurcation in snow states, but initial investigations point towards representation of the atmosphere rather than differences in assimilated data or snow schemes. This study demonstrates the ability of long-term reanalysis to reproduce snow variability accordingly.

  18. Atmospheric depo