WorldWideScience

Sample records for carbon balance studies

  1. Carbon balance of rewetted and drained peat soils used for biomass production: A mesocosm study

    DEFF Research Database (Denmark)

    Karki, Sandhya; Elsgaard, Lars; Kandel, Tanka;

    2016-01-01

    of lower CO2 emissions without losing agricultural land. The present study quantified the carbon balance (CO2, CH4 and harvested biomass C) of rewetted and drained peat soils under intensively managed reed canary grass (RCG) cultivation. Mesocosms were maintained at five different ground water levels (GWL...

  2. Comparative Modeling Studies of Boreal Water and Carbon Balance

    Science.gov (United States)

    Coughlan, J.; Peterson, David L. (Technical Monitor)

    1997-01-01

    The coordination of the modeling and field efforts for an Intensive Field Campaign (IFC) may resemble the chicken and egg dilemma. This session's theme advocates that early and proactive involvement by modeling teams can produce a scientific and operational benefit for the IFC and Experiment. This talk will provide some examples and suggestions originating from the NASA funded IFC's of the FIFE First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment, Oregon Transect Ecosystem Research (OTTER) and predominately Boreal Ecosystem-Atmosphere Study (BOREAS) Experiments. In February 1994 and prior to the final selection of the BOREAS study sites, a group of funded BOREAS investigators agreed to run their models with data for five community types representing the proposed tower flux sites. All participating models were given identical initial values and boundary conditions and driven with identical climate data. The objectives of the intercomparison exercise were: 1) compare simulation results of participating terrestrial, hydrological, and atmospheric models over selected time frames; 2) learn about model behavior and sensitivity to estimated boreal site and vegetation definitions; 3) prioritize BOREAS field data collection efforts supporting modeling studies; 4) identify individual model deficiencies as early as possible. Out of these objectives evolved some important coordination and science issues for the BOREAS Experiment that can be generalized to IFCs and long term archiving of the data. Some problems are acceptable because they are endemic to maintaining fair and open competition prior to the peer review process. Others are logistical and addressable through application of planning, management, and information sciences. This investigator has identified one source of measurement and model incompatibility that is manifest in the IFC scaling approach. Although intuitively obvious, scaling problems are already more formally defined in

  3. Carbon balance in Mediterranean ecosystems

    OpenAIRE

    Correia, Alexandra Cristina Pires

    2013-01-01

    Forests play an important role in climate change mitigation as they sequester and store carbon dioxide (CO2) from the atmosphere. The aim of this thesis was to investigate forest carbon balance in its main compartments: tress, understory and soils. We present methods to estimate carbon stock in biomass of stone pine stands in south Portugal. Allometric models, as well as conversion and expansion factors were presented allowing the quantification of stand carbon stocks irrespect...

  4. A paired flux approach to study the carbon balance of a corn/soybean rotation

    Science.gov (United States)

    Baker, J.; Griffis, T.

    2003-04-01

    There is intense interest in finding ways to damp projected increases in atmospheric CO_2 by adopting strategies that alter local rates of surface/atmosphere carbon exchange in ways that favor increased surface storage. It is generally accepted that row crop agriculture has historically been a contributor to the debit side of the terrestrial carbon ledger. However, changes in farming practice, primarily reduction of tillage, appear to have arrested this decline. The very fact that so much soil carbon was lost is now viewed positively, in the sense that it may represent a reservoir that can be refilled through the adoption of appropriate farming practices, but verification of carbon gain is a difficult problem. Soil sampling is the accepted standard, but it has a low signal to noise ratio and poor temporal resolution so it offers little insight into causes and effects or underlying processes. Micrometeorological methods address these shortcomings, replacing them with a new set of problems. Temporal resolution is superb, but determination of net carbon gain or loss requires integration of short-term (e.g. half-hourly) flux measurements over at least one full cycle of the system under test -- typically a year or more. Unfortunately, data are missed due to instrument failures and power outages, and other data must be discarded because theoretical assumptions of turbulent transport are not met. As a consequence, the end sum of net carbon exchange from these sites depends substantially on the gap-filling strategies that are used. Nonetheless, valuable information can be obtained by measuring differentially, i.e. making simultaneous flux measurements in two adjacent fields that are subjected to the same weather conditions, but with specific differences in farming practice. Insights into the differences in carbon balance between the systems, even in the face of the inevitable data gaps, can be obtained by considering only those time periods in which both fields are

  5. Study plan: Assessing ecosystem services and carbon balance in support of land management at the Great Dismal Swamp, Pocosin Lakes, and Alligator River National Wildlife Refuges

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study plan describes a collaborative research project to assess ecosystem services and estimate carbon balance in relation to water management and other...

  6. A carbon balance model of peach tree growth and development for studying the pruning response.

    Science.gov (United States)

    Génard, Michel; Pagès, Loïc; Kervella, Jocelyne

    1998-06-01

    We modeled tree responses to pruning on the basis of growth rules established on unpruned trees and a simple principle governing root-shoot interactions. The model, which integrates architectural and ecophysiological approaches, distinguishes four types of anatomical organs in a tree: rootstock, main axis, secondary axes and new roots. Tree structure is described by the position of secondary axes on the main axis. The main processes considered are plastochronal activity, branching, assimilate production, respiration and assimilate partitioning. Growth and development rules were based on measurements of two unpruned trees. The model was used to simulate growth of peach trees (Prunus persica (L.) Batsch) in their first growing season. Assuming that the equilibrium between roots and shoots tends to be restored after pruning, the response to removal of the main axis above the twentieth internode in mid-July was simulated and compared to the response measured in three pruned trees. The model fit the unpruned tree data reasonably well and predicted the main traits of tree behavior after pruning. Dry matter growth of the secondary axes of pruned trees was increased so that shoot seasonal carbon balance was hardly modified by pruning. Rhythmicity of growth was enhanced by pruning, and might result from variations induced in the root:shoot ratio. Variation in pruning severity had greater effects than variation in pruning date. A sensitivity analysis indicated that: (1) root-shoot partitioning was a critical process of the model; (2) tree growth was mainly dependent on assimilate availability; and (3) tree shape was highly dependent on the branching process.

  7. Carbon Mobilization in Oil Palm Plantation and Milling Based on a Carbon-Balanced Model – A Case Study in Thailand

    Directory of Open Access Journals (Sweden)

    Withida Patthanaissaranukool

    2011-07-01

    Full Text Available Damage to agricultural areas and household properties occurs more frequently all year round from extreme weather, which is believed to be due to climate change caused by the increase of greenhouse gases – particularly, CO2. In order to help reduce its concentration in the atmosphere, palm oil is a renewable energy which can be used for this purpose. In this study, the carbon mobilization of palm oil was investigated, from oil palm plantation process to the milling process, so as to determine the associated Carbon Equivalence (CE and the effects on human and land space. A carbon-balanced model (CBM is proposed herewith to indicate the main paths of carbon emission, fixation, and reduction. The net equivalent carbon emission was found to be 56 kg CE per ton of Crude Palm Oil (CPO produced, resulting in the emission flux of 175 kg CE/ha-y. The plantation activity that emits the highest CO2 levels is fertilizer application, accounting for about 84% of the total. All bio-residues produced from CPO production were found to be utilized for human use, thereby decreasing the carbon emission. Their use ranged from biogas and electricity generation to soil conditioning, and the utilization of the bio-residues resulted in total carbon reduction of 212 kg CE per ton of CPO. Carbon fixation as a main product (CPO was found to be an average of 812 kg CE per ton of CPO, equivalent to 2543 kg CE/ha-y. Overall, as the total fixation is 14 times higher than that of the total emissions, the production of CPO generates and introduces a very small amount of waste into the environment. To satisfy the need for palm oil as renewable energy and other end-user products the expansion of the plantation areas may result in competition of agricultural land with other cash crops.

  8. Instrumentation and analytical methods in carbon balance studies - inorganic components in a marine environment

    Energy Technology Data Exchange (ETDEWEB)

    Skjelvan, I.; Johannessen, T.; Miller, L.; Stoll, M.

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Substantial amounts of anthropogenic CO{sub 2} enters the atmosphere. The land biota acts as a sink for CO{sub 2}, with uncertain consequences. About 30% of the anthropogenic CO{sub 2} added to the atmosphere is absorbed by the ocean and how the ocean acts as a sink is central in understanding the carbon cycle. In their project the authors investigate the inorganic carbon in the ocean, especially total dissolved inorganic carbon, alkalinity, and partial pressure of CO{sub 2} (pCO{sub 2}) in surface ocean and atmosphere. To determine total dissolved inorganic carbon, coulometric analysis is used in which an exact amount of sea water is acidified and the amount of carbon extracted is determined by a coulometer. Alkalinity is determined by potentiometric titration. In the pCO{sub 2} measurement, a small amount of air is circulated in a large amount of sea water and when after some time the amount of CO{sub 2} in the air reflects the CO{sub 2} concentration in the water, the pCO{sub 2} in the gas phase is determined by infra-red detection. The atmospheric pCO{sub 2} is also determined, and the difference between the two partial pressures gives information about source or sink activities. Total carbon and alkalinity measurements are done on discrete samples taken from all depths in the ocean, but for partial pressure detection an underway system is used, which determines the pCO{sub 2} in the surface ocean continuously

  9. Forest fuel and carbon balances

    International Nuclear Information System (INIS)

    Forest fuel, i.e., branches and tops that remain after felling, are not considered to give a net surplus of carbon dioxide to the atmosphere. In order to, if possible, verify this theory a survey was made of the literature concerning different carbon flows related to forest fuel. Branches and needles that are not utilised as fuel nonetheless eventually become decomposed to carbon dioxide. Branches and stem wood are broken down in occasional cases to 60-80% already within 5-6 years but the decomposition rate varies strongly. A small amount of existing data suggest that branches and stems are broken down almost completely within 60-70 years, and earlier in some cases. Lignin is the component in needles and wood that is the most resistant to decomposition. Decomposition is favoured by optimal temperature and moisture, ground contact and ground animals. Material that is mulched during soil preparation is decomposed considerably faster than material that lies on the soil surface. Felling residues that are left on the soil are a large momentary addition to the soil's reserves of organic material but after a number of years the difference in soil organic material is small between places where fuel has been removed and places where felling residues have been left. High nitrogen deposition, fire control and effective forestry are factors that contribute to the increases in the reserves of soil organic material. It appears to be a good approximation to consider the forest fuel as being a neutral fuel as regards carbon dioxide in a longer perspective. In comparison with other biofuels and fossil fuels, forest fuel appears, together with Salix, to be the fuel that results in very little extra discharge of carbon dioxide or other greenhouse gases during its production, transport and processing. 70 refs, 5 figs, tabs

  10. Annual carbon balance of a peatland 10 yr following restoration

    Directory of Open Access Journals (Sweden)

    M. Strack

    2013-05-01

    Full Text Available Undisturbed peatlands represent long-term net sinks of carbon; however, peat extraction converts these systems into large and persistent sources of greenhouse gases. Although rewetting and restoration following peat extraction have taken place over the last several decades, very few studies have investigated the longer term impact of this restoration on peatland carbon balance. We determined the annual carbon balance of a former horticulturally-extracted peatland restored 10 yr prior to the study and compared these values to the carbon balance measured at neighboring unrestored and natural sites. Carbon dioxide (CO2 and methane (CH4 fluxes were measured using the chamber technique biweekly during the growing season from May to October 2010 and three times over the winter period. Dissolved organic carbon (DOC export was measured from remnant ditches in the unrestored and restored sites. During the growing season the restored site had greater uptake of CO2 than the natural site when photon flux density was greater than 1000 μmol m−2 s−1, while the unrestored site remained a source of CO2. Ecosystem respiration was similar between natural and restored sites, which were both significantly lower than the unrestored site. Methane flux remained low at the restored site except from open water pools, created as part of restoration, and remnant ditches. Export of DOC during the growing season was 5.0 and 28.8 g m−2 from the restored and unrestored sites, respectively. Due to dry conditions during the study year all sites acted as net carbon sources with annual balance of the natural, restored and unrestored sites of 250.7, 148.0 and 546.6 g C m−2, respectively. Although hydrological conditions and vegetation community at the restored site remained intermediate between natural and unrestored conditions, peatland restoration resulted in a large reduction in annual carbon loss from the system resulting in a carbon balance more similar to a natural

  11. Carbon balance of Russian agricultural land

    Science.gov (United States)

    Schepaschenko, D.; Shvidenko, A.; Schepaschenko, M.

    2012-04-01

    Russia managed 218.7 mln ha agricultural land (2009) in accordance with national statistics (FSSS, 2011: http://www.gks.ru/dbscripts/Cbsd/DBInet.cgi#1). Among that, 91.75 mln ha is arable land; 92.05 mln ha - hayfield and pasture; 34.9 mln ha - abandoned arable and fallow. Abandoned arable area is not indicated directly in the statistics, but can be calculated as a difference between "arable" and "cultivated" area. We estimated carbon balance of agricultural land by accounting carbon fluxes. Carbon sink includes: net primary productivity (NPP), applying fertilizes and liming. Carbon losses include soil respiration (SR), harvest and lateral flux. The initial data (cultivated area and harvest distribution by regions and crop) was derived from national agriculture statistics (FSSS, 2011). NPP was estimated via harvest and set of regression models. Average NPP for agricultural land was estimated at 435 g C m-2 (530 g C m-2 for crops). Soil respiration was calculated by a model (Mukhortova et. al., 1011: http://www.iiasa.ac.at/Research/FOR/forest_cdrom/Articles/Mukhortova_2011_IBFRA_SR.pdf) developed for Russia which is based on all available empirical data and accounted for climatic parameters, soil type and management practice. Average SR of agricultural land is 344 g C m-2 (372 g C m-2 for the cropland). We applied the IPCC method (National inventory, 2010; IPCC, 2006) for fertilizer and lateral fluxes assessment. The total carbon balance of agricultural land is almost in equilibrium (-0.04 t C ha-1) in spite of arable land is a carbon source (-0.84 t C ha-1). The highest sink (1.21 t C ha-1) is provided by abandoned land. Carbon fluxes vary substantially depending on seasonal weather conditions. For example grains' NPP in 2010 (dry and hot summer in major agricultural regions of European Russia) was estimated at 32% less compare to 2009 and the total carbon balance of this land category decreased by order of magnitude. We used Russian land cover (Schepaschenko et al

  12. The carbon balance of European croplands: a Trans-European, cross-site, multi model simulation study

    Science.gov (United States)

    Wattenbach, Martin; Sus, Oliver; Vuichard, Nicolas; Lehuger, Simon; Leip, Adrian; Gottschalk, Pia; Smith, Pete

    2010-05-01

    Croplands cover approximately 45% of Europe and play a significant role in the overall carbon budget of the continent. However, the estimation of the regional carbon balance is still uncertain. Here, we present a multi-site model comparison for four cropland ecosystem models namely the DNDC, ORCHIDEE-STICS, CERES-EGC and SPA model. We compare the accuracy of the models in predicting net ecosystem exchange (NEE), gross primary production (GPP), ecosystem respiration (Reco) as well as actual evapo-transpiration (ETa) for winter wheat (Triticum aestivum L.), winter barley (Hordeum vulgare L.) and maize (Zea mays L.) derived from eddy covariance measurements on five sites of the CarboEurope IP network. The models are all able to simulate mean daily GPP. The simulation results for mean daily ETa and Reco are, however, less accurate. The resulting simulation of daily NEE is adequate beside some cases where models fail due to a lack in phase and amplitude alignment. ORCHIDEE-STICS and the SPA demonstrate the best performance, nevertheless, they are not able to simulate full crop rotations under consideration of multiple management. CERES-EGC and especially DNDC although exhibiting a lower level of model accuracy are able to simulate such conditions resulting in more accurate annual cumulative NEE.

  13. Climate change, fire and the carbon balance

    International Nuclear Information System (INIS)

    On average, forest fires have burned 2 to 3 million hectares annually in Canada over the last twenty years. Over the last 40 years, this amounts to 20 per cent of the amount of carbon released through fossil fuel emissions in Canada. This paper analyses the extent to which climate change may contribute to a disturbance in the carbon balance due to increased fire activity. In addition, data from FLUXNET-Canada was examined, indicating that carbon fluxes from younger forests show dramatic changes in diurnal carbon flux patterns, caused by reduced photosynthetic uptake during the day and less root respiration at night. Increases in fire are expected throughout much of the boreal forest towards the end of this century, with a lengthening of the fire season and increases in severity and intensity. It was concluded that there is the possibility of a positive feedback, where climate change could cause more fires, resulting in a greater release of carbon and thereby increasing greenhouse gas concentrations. Evidence that smoke promoted positive lightning strikes while reducing precipitation was also presented. It was suggested that certain self-limiting factors may prevent a run-away scenario. Changes to human and lightning ignition patterns, for example, may have an impact. It was also suggested that research efforts should focus on refining climate change estimates that account for landscape change and other aspects that control fire in Canada. 9 refs., 2 figs

  14. Methodology for calculation of carbon balances for biofuel crops production

    Science.gov (United States)

    Gerlfand, I.; Hamilton, S. K.; Snapp, S. S.; Robertson, G. P.

    2012-04-01

    Understanding the carbon balance implications for different biofuel crop production systems is important for the development of decision making tools and policies. We present here a detailed methodology for assessing carbon balances in agricultural and natural ecosystems. We use 20 years of data from Long-term Ecological Research (LTER) experiments at the Kellogg Biological Station (KBS), combined with models to produce farm level CO2 balances for different management practices. We compared four grain and one forage systems in the U.S. Midwest: corn (Zea mays) - soybean (Glycine max) - wheat (Triticum aestivum) rotations managed with (1) conventional tillage, (2) no till, (3) low chemical input, and (4) biologically-based (organic) practices; and (5) continuous alfalfa (Medicago sativa). In addition we use an abandoned agricultural field (successionnal ecosystem) as reference system. Measurements include fluxes of N2O and CH4, soil organic carbon change, agricultural yields, and agricultural inputs (e.g. fertilization and farm fuel use). In addition to measurements, we model carbon offsets associated with the use of bioenergy from agriculturally produced crops. Our analysis shows the importance of establishing appropriate system boundaries for carbon balance calculations. We explore how different assumptions regarding production methods and emission factors affect overall conclusions on carbon balances of different agricultural systems. Our results show management practices that have major the most important effects on carbon balances. Overall, agricultural management with conventional tillage was found to be a net CO2 source to the atmosphere, while agricultural management under reduced tillage, low input, or organic management sequestered carbon at rates of 93, -23, -51, and -14 g CO2e m-2 yr-1, respectively for conventionally tilled, no-till, low-input, and organically managed ecosystems. Perennial systems (alfalfa and the successionnal fields) showed net carbon

  15. The Sub-Saharan Africa carbon balance, an overview

    Directory of Open Access Journals (Sweden)

    A. Bombelli

    2009-02-01

    Full Text Available This study presents a summary overview of the carbon balance of Sub-Saharan Africa (SSA by synthesizing the available data from national communications to UNFCCC and first results from the project CarboAfrica (net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates. According to these preliminary estimates the overall carbon balance of SSA varies from 0.43 Pg C y−1 (using in situ measurements for savanna NEP to a much higher sink of 2.53 Pg C y−1 (using model estimates for savanna NEP. UNFCCC estimates lead to a moderate carbon sink of 0.58 Pg C y−1. Excluding anthropogenic disturbance and intrinsic episodic events, the carbon uptake by forests (0.98 Pg C y−1 and savannas (from 1.38 to 3.48 Pg C y−1, depending on the used methodology are the main components of the SSA sink effect. Fires (0.72 Pg C y−1, deforestation (0.25 Pg C y−1 and forest degradation (0.77 Pg C y−1 are the main contributors to the SSA carbon emissions, while the agricultural sector contributes only with 0.12 Pg C y−1. Notably, the impact of forest degradation is higher than that caused by deforestation, and the SSA forest net carbon balance is close to equilibrium. Savannas play a major role in shaping the SSA carbon balance, due to their large areal extent, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. This paper shows that Africa plays a key role in the global carbon cycle system and probably could have a potential for carbon sequestration higher than expected, even if still highly uncertain. Further investigations are needed, particularly to better address the role of savannas and tropical forests. The current CarboAfrica network of carbon measurements could provide future unique data sets for better estimating the

  16. Drivers and patterns of land biosphere carbon balance reversal

    Science.gov (United States)

    Müller, Christoph; Stehfest, Elke; van Minnen, Jelle G.; Strengers, Bart; von Bloh, Werner; Beusen, Arthur H. W.; Schaphoff, Sibyll; Kram, Tom; Lucht, Wolfgang

    2016-04-01

    The carbon balance of the land biosphere is the result of complex interactions between land, atmosphere and oceans, including climatic change, carbon dioxide fertilization and land-use change. While the land biosphere currently absorbs carbon dioxide from the atmosphere, this carbon balance might be reversed under climate and land-use change (‘carbon balance reversal’). A carbon balance reversal would render climate mitigation much more difficult, as net negative emissions would be needed to even stabilize atmospheric carbon dioxide concentrations. We investigate the robustness of the land biosphere carbon sink under different socio-economic pathways by systematically varying climate sensitivity, spatial patterns of climate change and resulting land-use changes. For this, we employ a modelling framework designed to account for all relevant feedback mechanisms by coupling the integrated assessment model IMAGE with the process-based dynamic vegetation, hydrology and crop growth model LPJmL. We find that carbon balance reversal can occur under a broad range of forcings and is connected to changes in tree cover and soil carbon mainly in northern latitudes. These changes are largely a consequence of vegetation responses to varying climate and only partially of land-use change and the rate of climate change. Spatial patterns of climate change as deduced from different climate models, substantially determine how much pressure in terms of global warming and land-use change the land biosphere will tolerate before the carbon balance is reversed. A reversal of the land biosphere carbon balance can occur as early as 2030, although at very low probability, and should be considered in the design of so-called peak-and-decline strategies.

  17. Carbon and energy balances for a range of biofuels options

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, M.A.; Matthews, R.; Mortimer, N.D.

    2003-03-01

    This is the final report of a project to produce a set of baseline energy and carbon balances for a range of electricity, heat and transport fuel production systems based on biomass feedstocks. A list of 18 important biofuel technologies in the UK was selected for study of their energy and carbon balances in a consistent approach. Existing studies on these biofuel options were reviewed and their main features identified in terms of energy input, greenhouse gas emissions (carbon dioxide, methane, nitrous oxide and total), transparency and relevance. Flow charts were produced to represent the key stages of the production of biomass and its conversion to biofuels. Outputs from the study included primary energy input per delivered energy output, carbon dioxide outputs per delivered energy output, methane output per delivered energy output, nitrous oxide output per delivered energy output and total greenhouse gas requirements. The net calorific value of the biofuel is given where relevant. Biofuels studied included: biodiesel from oilseed rape and recycled vegetable oil; combined heat and power (CHP) by combustion of wood chip from forestry residues; CHP by gasification of wood chip from short rotation coppice; electricity from the combustion of miscanthus, straw, wood chip from forestry residues and wood chip from short rotation coppice; electricity from gasification of wood chip from forestry residues and wood chip from short rotation coppice; electricity by pyrolysis of wood chip from forestry residues and wood chip from short rotation coppice; ethanol from lignocellulosics, sugar beet and wheat; heat (small scale) from combustion of wood chip from forestry residues and wood chip from short rotation coppice; and rapeseed oil from oilseed rape.

  18. CARBON BALANCE OF THE CONTINUOUS PERMAFROST ZONE OF RUSSIA

    Science.gov (United States)

    An increase in the atmospheric concentration of CO2 is projected to cause climate warming. arming of the permafrost environment could change the balance between carbon accumulation and decomposition processes and substantially disrupt the equilibrium of the carbon cycle. arming m...

  19. Balance and forecasts of french carbon dioxide emissions

    International Nuclear Information System (INIS)

    This paper strikes the balance of carbon dioxide emissions in France between 1986 and 1991 and gives forecasts till 2010. Since 1986, France has reduced its efforts for energy conservation and air pollution by carbon dioxide begins to growth again in connection with consumption growth in transport area, development of computer and simulation needs

  20. Carbon balance along the Northeast China Transect(NECT-IGBP)

    Institute of Scientific and Technical Information of China (English)

    周广胜; 王玉辉; 蒋延玲; 许振柱

    2002-01-01

    The Northeast China Transect (NECT) along a precipitation gradient wasused to calculate the carbon balance of different vegetation types, land-use practices and temporal scales. NECT consists of mixed coniferous-broadleaved forest ecosystems, meadow steppe ecosystems and typical steppe ecosystems. Analyses of the C budget were carried out with field measurement based on dark enclosed chamber techniques and alkali absorption methods, and the application of the CENTURY model. Results indicated that: (1) soil CO2 flux had a strong diurnal and seasonal variation influenced by grassland type and land-use practices. However, the seasonal variation on soil CO2 fluxes did not show obvious changes between non-grazing and grazing Leymus chinensis dominated grasslands. (2) Hourly soil CO2 fluxes mainly depended on temperature, while daily CO2 fluxes were affected bothby temperature and moisture. (3) NPP of the three typical ecosystems showed linear relationships with inter-annual precipitation, but total soil carbon of those ecosystems did not. NPP and total soil carbon values decreased westward with decreasing precipitation. (4) Model simulation of NPP and total soil carbon showed that mean annual precipitation was the major limiting factor for ecosystem productivity along NECT. (5) Mean annual carbon budget is the largest for the mixedconiferous- broadleaved forest ecosystem (503.2 gC m-2 a-1), followed by the meadow steppe ecosystem (227.1 gC m-2 a-1), and the lowest being the typical steppe ecosystem (175.8 gC m-2 a-1). This study shows that concurrent field measurements of terrestrial ecosystems including the soil and plant systems with surface layer measurements along the water-driven IGBP-NECT are valuable in understanding the mechanisms driving the carbon cycle in different vegetation types under different land-use practices. Future transect research should be emphasized.

  1. Modelling the role of fires in the terrestrial carbon balance by incorporating SPITFIRE into the global vegetation model ORCHIDEE – Part 2: Carbon emissions and the role of fires in the global carbon balance

    OpenAIRE

    C Yue; Ciais, P.; P. Cadule; Thonicke, K.; T. T. van Leeuwen

    2015-01-01

    Carbon dioxide emissions from wild and anthropogenic fires return the carbon absorbed by plants to the atmosphere, and decrease the sequestration of carbon by land ecosystems. Future climate warming will likely increase the frequency of fire-triggering drought, so that the future terrestrial carbon uptake will depend on how fires respond to altered climate variation. In this study, we modelled the role of fires in the global terrestrial carbon balance for 1901–2012, using th...

  2. Modelling the role of fires in the terrestrial carbon balance by incorporating SPITFIRE into the global vegetation model ORCHIDEE – Part 2: Carbon emissions and the role of fires in the global carbon balance

    OpenAIRE

    C Yue; Ciais, Philippe; P. Cadule; Thonicke, K.; T. T. van Leeuwen

    2015-01-01

    Carbon dioxide emissions from wild and anthropogenic fires return the carbon absorbed by plants to the atmosphere, and decrease the sequestration of carbon by land ecosystems. Future climate warming will likely increase the frequency of fire-triggering drought, so that the future terrestrial carbon uptake will depend on how fires respond to altered climate variation. In this study, we modelled the role of fires in the global terrestrial carbon balance for 1901–2012, using the ORCHIDEE global ...

  3. Modelling the role of fires in the terrestrial carbon balance by incorporating SPITFIRE into the global vegetation model ORCHIDEE - Part 2 : Carbon emissions and the role of fires in the global carbon balance

    OpenAIRE

    C Yue; Ciais, P.; P. Cadule; Thonicke, K.; T. T. van Leeuwen

    2015-01-01

    Carbon dioxide emissions from wild and anthropogenic fires return the carbon absorbed by plants to the atmosphere, and decrease the sequestration of carbon by land ecosystems. Future climate warming will likely increase the frequency of fire-triggering drought, so that the future terrestrial carbon uptake will depend on how fires respond to altered climate variation. In this study, we modelled the role of fires in the global terrestrial carbon balance for 1901-2012, using the ORCHIDEE global ...

  4. Modelling the role of fires in the terrestrial carbon balance by incorporating SPITFIRE into the global vegetation model ORCHIDEE – Part 2: Carbon emissions and the role of fires in the global carbon balance

    OpenAIRE

    C Yue; Ciais, P.; P. Cadule; Thonicke, K.; T. T. van Leeuwen

    2014-01-01

    Carbon dioxide emissions from wild and anthropogenic fires return the carbon absorbed by plants to the atmosphere, and decrease the sequestration of carbon by land ecosystems. Future climate warming will likely increase the frequency of fire-triggering drought; so that the future terrestrial carbon uptake will depend on how fires respond to altered climate variation. In this study, we modelled the role of fires in the global terrestrial carbon balance for 19...

  5. Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

    NARCIS (Netherlands)

    Kindler, R.; Siemens, J.; Kaiser, K.; Moors, E.J.

    2011-01-01

    Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH4), at forests, grasslands, and

  6. Impact of rapeseed cropping on the soil carbon balance

    Science.gov (United States)

    Moffat, Antje Maria; Herbst, Mathias; Huth, Vytas; Andres, Monique; Augustin, Jürgen

    2015-04-01

    Winter oilseed rape is the dominant biofuel crop in the young moraine landscape in Northern Germany. Since the cultivation of biofuel crops requires sustainability compared to fossil fuels by law, detailed knowledge about their green house gas (GHG) balance is necessary. The soil carbon balance is one of the key contributors to the total GHG balance and also very important for the assessment of soil fertility. However, the knowledge about the impact of different management practices on the soil carbon balance is very limited up to now. Therefore, we investigated the carbon fluxes of winter oilseed rape at field plots near Dedelow/Uckermark in NE Germany with different treatments of fertilization (mineral versus organic) and tillage (no-till and mulch-till versus ploughing). The dynamics of the carbon fluxes are mainly driven by the current climatic conditions but the overall response depends strongly on the ecosystem state (with its physiological and microbiological properties) which is affected by management. To get the full carbon flux dynamics but also the impact of the different management practices, two different approaches were used: The eddy covariance technique to get continuous fluxes throughout the year and the manual chamber technique to detect flux differences between specific management practices. The manual chamber measurements were conducted four-weekly as all-day campaigns using a flow-through non-steady-state closed chamber system. The fluxes in-between campaigns were gap-filled based on functional relationships with soil and air temperature (for the ecosystem respiration) and photosynthetic active radiation (for the gross primary production). All results presented refer to the cropping season 2012-2013. The combination of the two measurement techniques allows the evaluation of chamber fluxes including an independent estimate of the error on the overall balances. Despite the considerable errors, there are significant differences in the soil carbon

  7. Net Carbon Balance for the Brazilian Amazon

    Science.gov (United States)

    Houghton, R. A.

    1998-01-01

    The general purpose of this research was to use recent satellite-based estimates of deforestation in Brazilian Amazonia to calculate the net flux of carbon associated with deforestation and subsequent regrowth of secondary forests. We have made such a calculation, in the process comparing two estimates of deforestation and two estimates of biomass for the region. Both estimates were based on the RADAMBRASIL survey. They differed in the equations used to convert wood-volumes to total biomass. The net flux of carbon from changes in land use seems to vary from year to year, perhaps by as much as a factor of 4.

  8. Water and Carbon Balance Modeling: Methods of Uncertainty Analysis

    OpenAIRE

    Juston, John

    2010-01-01

    How do additional data of the same and/or different type contribute to reducing model parameter and predictive uncertainties? This was the question addressed with two models – the HBV hydrological water balance model and the ICBM soil carbon balance model – that were used to investigate the usefulness of the Generalized Likelihood Uncertainty Estimation (GLUE) method for calibrations and uncertainty analyses.  The GLUE method is based on threshold screening of Monte Carlo simulations using so...

  9. Carbon balance of a drained forested bog in southern Finland

    Science.gov (United States)

    Minkkinen, Kari; Penttilä, Timo; Ojanen, Paavo; Lohila, Annalea

    2016-04-01

    Carbon and greenhouse gas (GHG) dynamics of a drained forested peatland in southern Finland were measured over multiple years, including one with severe drought during growing season. Net ecosystem carbon dioxide exchange (NEE) was measured with an eddy covariance method from a tower above the forest. Soil and forest floor CO2, CH4 and N2O fluxes were measured from the strips and from ditches with closed chambers. Biomasses and litter production were sampled, and soil subsidence was measured by consequtive levelings of the peat surface. The data were used to estimate the ecosystem C pools and annual fluxes of carbon and GHGs of the peatland and to analyse the impact of periodical drought on the carbon fluxes. The drained peatland was a strong sink of carbon dioxide in all studied years. Soil CO2 balance was estimated by subtracting the carbon sink of the growing tree stand from NEE, and it showed that also the soil was a sink of carbon in all studied years. A drought period in one summer significantly decreased the sink through decreased GPP. Drought also decreased the ecosystem respiration, including soil respiration. Decreasing water table thus did not increase, but rather decreased CO2 efflux from the peat soil. The site was a small sink for CH4, even when emissions from ditches were included. N2O emissions were small from all surfaces. Despite of the continuous carbon sink, peat surface subsided slightly (1.4 mm a-1) during the 10-year measurement period, which is interpreted to mean mainly compaction, rather than oxidation of the peat. It is concluded that this drained peatland acts as a continuous soil C sink similarly to an undrained peatland. The reason may be the relatively small water-level drawdown compared to an undrained situation, the consequently rather small changes in plant community structure and the significantly improved tree stand growth and litter production. The consequences of continuing production forestry vs. restoration of the site on the

  10. Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

    DEFF Research Database (Denmark)

    Kindler, Reimo; Siemens, Jan; Kaiser, Klaus;

    2011-01-01

    Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH4), at forests, grasslands, a...... solubility of CO2 in acidic forest soil solutions and large NEE. Leaching of CH4 proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems.......Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH4), at forests, grasslands...... ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24–105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small...

  11. Measuring and Modelling the Carbon Balance of Pinus palustris Savannas

    Science.gov (United States)

    Wright, J. K.; Williams, M. D.; Mitchell, R. J.; Starr, G.; McGee, J.; Whelan, A.

    2011-12-01

    Longleaf pine savannas currently occupy 1.4 million hectares in the South Eastern USA - only 2.6% of their original range. These fire-dependent ecosystems are highly biodiverse and of economic and ecological importance to the region. This region of the United States, however, is increasingly prone to severe drought, including a classified "exceptional" drought in 2011. Drought occurrence and severity are likely to increase in future climate scenarios. Moreover, increasing drought and accompanying wildfire will influence the carbon balance of the South East, a region identified as having the highest carbon sequestration potential in the USA. Thus, understanding the effects of drought on the native longleaf pine savanna land cover, therefore, is of both scientific and economic interest. Longleaf pine exists over a wide soil moisture gradient, driven by the texture and drainage capacity of the soils. These ecosystems therefore provide a natural laboratory for exploring the interaction between productivity, fire and water use. Here we present results of a 3 year study comparing the ecophysiology and carbon balance of two adjacent (5 mile separation) longleaf pine savanna flux sites, one xeric, one mesic. A process-based model (Soil-Plant-Atmosphere - SPA) and leaf-level measurements of photosynthesis and water use in drought and non-drought periods have enabled the authors to partition the carbon fluxes observed at each site into three functional groups (C4 understorey, C3 canopy and mid-storey). Results of this study show that the comparative overall productivity of wet and dry longleaf pine savannas varies through the year, with both wet and dry sites achieving similar productivity in the summer months but with the wet site exceeding the dry site during winter. We hypothesise that this difference is due to the activity of the seasonal C4 understorey. Results from SPA, flux data and field measurements suggest the understorey, dominated by the C4 grass Aristida stricta

  12. Amazon old-growth forest wind disturbance and the regional carbon balance

    Science.gov (United States)

    Chambers, J. Q.; Negron Juarez, R. I.; Marra, D. M.; Roberts, D. A.; Hurtt, G. C.; Lima, A.; Higuchi, N.

    2010-12-01

    Estimating the carbon balance of a landscape is challenging. A key problem is determining whether or not measurements made in plots are representative of the carbon state of a larger region. A key parameter for calculating landscape carbon balance is the return frequency of episodic disturbances. If disturbances are clustered and occur more frequently than the time required for biomass recovery, a spatial mixture of patches in different stages of recovery occurs. Under these shifting steady-state mosaic conditions, quantifying the mean state of ecosystem attributes such as carbon balance or tree species diversity is difficult. In this study, satellite remote sensing (Landsat) was coupled with field investigations to create ~25 year landscape-scale disturbance chronosequence for old-growth forest in the Central Amazon. The detected disturbances were caused by strong storms which resulted in tree mortality events ranging from small clusters of 7-10 downed trees, to large contiguous blowdowns larger than 30 ha in size. Using the chronosequence, a cumulative probability distribution function was developed, which followed a power law, and was used to parameterize a forest carbon balance model. Results demonstrate that for power law exponents less than about 2.0, the spatial scale at which forest carbon balance establishes is much larger than generally expected. Ultimately, an increase in wind disturbance frequency and/or intensity with a warming climate has the potential to cause a net loss of carbon from Amazon forests to the atmosphere.

  13. Carbon and water vapor balance in a subtropical pine plantation

    Directory of Open Access Journals (Sweden)

    Posse G

    2016-10-01

    Full Text Available Afforestation has been proposed as an effective tool for protecting primary and/or secondary forests and for mitigating atmospheric CO2. However, the dynamics of primary productivity differs between plantations and natural forests. The objective of this work was to evaluate the potential for carbon storage of a commercial pine plantation by determining its carbon balance. Measurements started when trees were aged 6 and ended when they were older than 8 years. We measured CO2 and water vapor concentrations using the Eddy covariance method. Gross primary productivity in 2010 and 2011 was 4290 ± 473 g C m-2 and 4015 ± 485 g C m-2, respectively. Ecosystem respiration ranged between 7 and 20 g C m-2 d-1, reaching peaks in all Februaries. Of the 30 months monitored, the plantation acted as carbon source for 21 months and as carbon sink for 6 months, while values close to neutrality were obtained during 3 months. The positive balance representing CO2 loss by the system was most likely due to the cut branches left on the ground following pruning activities. The plantation was subjected to pruning in January and September 2008 and to sanitary pruning in October 2010. In all cases, cut branches were not removed but remained on the ground. Residue management seems to have a very important impact on carbon balance.

  14. Simulation of terrestrial carbon cycle balance model in Tibet

    Institute of Scientific and Technical Information of China (English)

    WANGJianlin:; HUDan; SUNZibao

    2003-01-01

    Based on climate material, the simplified terrestrial carbon cycle balance (TCCB) model was established, which is semi-mechanism and semi-statistics. Through TCCB model, our estimate indicates that the southeastern part of the Tibetan Plateau has much higher carbon content, and we have calculated the litter carbon pool, NPP, carbon fluxes and described their spatial characteristics in this region. Based on the TCCB model simulation, NPP in Tibet is 1.73 × 108tC/a, soil organic input rate is 0.66 × l08 tC/a, litter mineralization rate is 1.07× l08tC/a, vegetation litterfall rate is 1.73× l08 tC/a, the litter carbon pool is 7.26 × l08 tC, and soil decomposition rate is 309.54 × l08tC/a. The carbon budget was also analyzed based on the estimates of carbon pool and fluxes. The spatial distributions of carbon pools and carbon fluxes in different compartments of terrestrial ecosystem were depicted with map respectively in Tibet. The distribution of NPP, vegetation litterfall rate, litter, litter mineralization rate, soil organic input rate and the soil decomposition rate were abstracted with temperature, precipitation, fractional vegetation and land feature.

  15. The carbon balance of terrestrial ecosystems of China

    Directory of Open Access Journals (Sweden)

    Pilli R

    2009-05-01

    Full Text Available A comment is made on a recent letter published on Nature, in which different methodologies are applied to estimate the carbon balance of terrestrial ecosystems of China. A global carbon sink of 0.19-0.26 Pg per year is estimated during the 1980s and 1990s, and it is estimated that in 2006 terrestrial ecosystems have absorbed 28-37 per cent of global carbon emissions in China. Most of the carbon absorption is attributed to large-scale plantation made since the 1980s and shrub recovery. These results will certainly be valuable in the frame of the so-called “REDD” (Reducing Emissions from Deforestation forest Degradation in developing countries mechanism (UN convention on climate change UNFCCC.

  16. Potential reduction of carbon emissions from Crude Palm Oil production based on energy and carbon balances

    International Nuclear Information System (INIS)

    Highlights: ► We evaluate energy and carbon equivalence from CPO production based on a CBM. ► Energy spent and produced via carbon movement from palm oil mill was determined. ► Scenarios were formulated to evaluate the potential reduction of carbon emission. ► Utilization of biomass from palm oil mill shows the high potential of C-reduction. -- Abstract: This study aimed to evaluate energy and carbon equivalences (CE) associated with palm oil milling and to evaluate sustainability alternatives for energy consumption. Appropriate ways to reduce carbon emissions were also evaluated. A field survey was carried out to quantify the input and output of energy and materials following the conceptual framework of a carbon-balanced model (CBM), which exclude other non-CO2 greenhouse gases. Survey results indicate that the electrical energy consumption for daily mill start-up averaged 18.7 ± 5.4 kWh/ton Fresh Fruit Bunches (FFBs). This energy is equivalent to 114.4 ± 33.2 kWh/ton Crude Palm Oil (CPO) which was found to be offset by that generated in the mills using palm fiber as a solid fuel. Currently, organic residues contained in the wastewater are anaerobically converted to methane. The methane is used as fuel to generate electricity and sold to an outside grid network at a generation rate of 8.1 ± 2.1 kWh/ton FFB. Based on the CBM approach, carbon emissions observed from the use of fossil energy in palm oil milling were very small; however, total carbon emission from oil palm plantation and palm oil milling were found to be 12.3 kg CE/ton FFB, resulting in the net carbon reduction in CPO production of 2.8 kg CE/ton FFB or 53.7 kg CE/ha-y. Overall, the sum of C-reduction was found 1.2 times greater than that of C-emission. This figure can be increased up to 5.5, if all biomass by-products are used as fuel to generate electricity only. The full potential for carbon reduction from palm oil milling is estimated at 0.94 kW of electric power for every hectare of

  17. Evaluation of Carbon and Oxygen Balances in Urban Ecosystems Using Land Use/Land Cover and Statistical Data

    OpenAIRE

    Kai Yin; Dengsheng Lu; Yichen Tian; Qianjun Zhao; Chao Yuan

    2014-01-01

    Urban areas play an important role in the global carbon cycle, and human-induced carbon emissions from urban areas urgently need to be reduced. Therefore, understanding the relationship between carbon sources and sinks is the first step toward mitigating the effect of urban areas on climate change. Combined with the land use and land cover (LULC) empirical coefficients and statistical methods, urban carbon and oxygen balances in Beijing were evaluated. In this study, the carbon sequestration ...

  18. Carbon balance and water use efficiency of frequently cut Lolium perenne L. swards at elevated carbon dioxide

    NARCIS (Netherlands)

    Schapendonk, A.H.C.M.; Dijkstra, P.; Groenwold, J.; Pot, C.S.; Geijn, van de S.C.

    1997-01-01

    The impact of doubled atmospheric [CO2] on the carbon balance of regularly cut Lolium perenne L. swards was studied for two years under semi-field conditions in the Wageningen Rhizolab. CO2 and H2O vapour exchange rates of the swards were measured continuously for two years in transparent enclosures

  19. Environmental change and the carbon balance of Amazonian forests.

    Science.gov (United States)

    Aragão, Luiz E O C; Poulter, Benjamin; Barlow, Jos B; Anderson, Liana O; Malhi, Yadvinder; Saatchi, Sassan; Phillips, Oliver L; Gloor, Emanuel

    2014-11-01

    Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21st Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990s mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990s and early 2000s to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) Pg C year(-1) in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP = -0.06 (-0.31 to +0.01) Pg C year(-1) ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency. PMID:25324039

  20. Variability and recent trends in the African carbon balance

    Directory of Open Access Journals (Sweden)

    P. Ciais

    2008-09-01

    Full Text Available We modeled the African carbon balance over the past century using the process based ORCHIDEE model, forced by changing climate and human induced changes in land use. The model includes a simple parameterization of natural fires, but the natural vegetation dynamics was ignored. The period analyzed is 1901–2002. Overall, we found that the African net carbon balance (Net Biome Productivity, NBP increased from a net carbon source of −0.14 Pg C yr−1 in the 1980s to a net carbon sink of 0.15 Pg C yr−1 in the 1990s. Deforestation is estimated to be a source of 0.13 Pg C yr−1, implying a compensating effect of climate trends (mainly increasing precipitation plus CO2 fertilization, causing a sink of 0.28 Pg C yr−1. We found that the interannual variability of NBP is mostly driven by photosynthesis changes. Over savannas, photosynthesis changes from one year to the next are strongly correlated with rainfall changes (R2=0.77 in northern Africa, and R2=0.42 in southern African savannas. Over forests, such a control by rainfall is not found. The main spatial pattern of interannual variability in NBP and in gross carbon fluxes is related with ENSO, with dryer conditions prevailing over savannas during El Niño and wetter conditions over forests. Climate induced variations in fire emissions respond to this ENSO forcing, but they do not determine strongly the NBP variations. Finally, we model that ecosystem respiration variations (mostly due to autotrophic respiration are tailing with those of photosynthesis, on interannual as well as on decadal time scales, but this result is uncertain given the potential for acclimation for autotrophic respiration processes.

  1. The Carbon-Nitrogen Balance of the Nodule and Its Regulation under Elevated Carbon Dioxide Concentration

    Directory of Open Access Journals (Sweden)

    Marc Libault

    2014-01-01

    Full Text Available Legumes have developed a unique way to interact with bacteria: in addition to preventing infection from pathogenic bacteria like any other plant, legumes also developed a mutualistic symbiotic relationship with one gender of soil bacteria: rhizobium. This interaction leads to the development of a new root organ, the nodule, where the differentiated bacteria fix for the plant the atmospheric dinitrogen (atmN2. In exchange, the symbiont will benefit from a permanent source of carbon compounds, products of the photosynthesis. The substantial amounts of fixed carbon dioxide dedicated to the symbiont imposed to the plant a tight regulation of the nodulation process to balance carbon and nitrogen incomes and outcomes. Climate change including the increase of the concentration of the atmospheric carbon dioxide is going to modify the rates of plant photosynthesis, the balance between nitrogen and carbon, and, as a consequence, the regulatory mechanisms of the nodulation process. This review focuses on the regulatory mechanisms controlling carbon/nitrogen balances in the context of legume nodulation and discusses how the change in atmospheric carbon dioxide concentration could affect nodulation efficiency.

  2. Carbon balance of an intensively grazed permanent grassland in southern Belgium

    Science.gov (United States)

    Gourlez de la Motte, Louis; Jérôme, Elisabeth; Mamadou, Ossénatou; Beckers, Yves; Bodson, Bernard; Heineisch, Bernard; Aubinet, Marc

    2016-04-01

    Grasslands are an important component of the global carbon balance but their carbon storage potential is still highly uncertain. Especially, the impact of weather variability and management practices on grassland carbon budgets need to be assessed. This study investigates the carbon balance of an intensively managed permanent grassland (Dorinne Terrestrial Observatory (DTO)) and its uncertainties by combining 5-years of eddy covariance measurements and other organic carbon exchanges estimates. The specificities of this study lie in: (i) the age of the pasture, which has probably been established since more than one century; (ii) the intensive character of the management with a mean grazing pressure larger than 2 livestock unit ha-1 and stocking cycle including stocking and rest periods, (iii) the livestock production system, typical of Wallonia, farming intensively Belgian Blue breed of cattle in order to produce meat. The results showed that, despite the high stocking rate and the old age of the pasture and the high stocking rate, the site acted as a relatively stable carbon sink from year to year with a 5-year average Net Biome Productivity of ‒173 [‒128 ‒203] g C m-2 yr-1. The carbon sink behavior of the pasture was directly increased by management practices through food complementation and organic fertilization and indirectly by mineral fertilization. The relatively low carbon budget inter-annual variability could be explained both by: (i) grazing management of the farmer that regulated Growth Primary Productivity by adapting the stocking rate to the Leaf Area Index which itself depends on weather conditions, (ii) carbon imports through food complements only when grass regrowth was not sufficient to feed the cattle. The results suggest that management practices that tend to optimize forage availability for meat production could contribute to maintaining a carbon sink. Keywords : grassland, carbon budget, carbon dioxide flux, management, eddy covariance

  3. Impacts of urbanization on carbon balance in terrestrial ecosystems of the Southern United States

    International Nuclear Information System (INIS)

    Using a process-based Dynamic Land Ecosystem Model, we assessed carbon dynamics of urbanized/developed lands in the Southern United States during 1945–2007. The results indicated that approximately 1.72 (1.69–1.77) Pg (1P = 1015) carbon was stored in urban/developed lands, comparable to the storage of shrubland or cropland in the region. Urbanization resulted in a release of 0.21 Pg carbon to the atmosphere during 1945–2007. Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. After a rapid decline of carbon storage during land conversion, an urban ecosystem gradually accumulates carbon and may compensate for the initial carbon loss in 70–100 years. The carbon sequestration rate of urban ecosystem diminishes with time, nearly disappearing in two centuries after land conversion. This study implied that it is important to take urbanization effect into account for assessing regional carbon balance. - Highlights: ► A series of spatial and temporal urban/developed land maps were generated. ► Urbanization effects on regional carbon dynamics were studied with a process-based Dynamic Land Ecosystem Model (DLEM). ► Carbon storage of urban/developed land was comparable to that stored in cropland and shrubland in the Southern United States. ► Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. ► Urbanization resulted in carbon emission, but established urban areas may gradually accumulate carbon over time. - Urbanization has resulted in carbon release to the atmosphere, but established urban areas may gradually accumulate carbon over time.

  4. Stand age and climate drive forest carbon balance recovery

    Science.gov (United States)

    Besnard, Simon; Carvalhais, Nuno; Clevers, Jan; Herold, Martin; Jung, Martin; Reichstein, Markus

    2016-04-01

    Forests play an essential role in the terrestrial carbon (C) cycle, especially in the C exchanges between the terrestrial biosphere and the atmosphere. Ecological disturbances and forest management are drivers of forest dynamics and strongly impact the forest C budget. However, there is a lack of knowledge on the exogenous and endogenous factors driving forest C recovery. Our analysis includes 68 forest sites in different climate zones to determine the relative influence of stand age and climate conditions on the forest carbon balance recovery. In this study, we only included forest regrowth after clear-cut stand replacement (e.g. harvest, fire), and afforestation/reforestation processes. We synthesized net ecosystem production (NEP), gross primary production (GPP), ecosystem respiration (Re), the photosynthetic respiratory ratio (GPP to Re ratio), the ecosystem carbon use efficiency (CUE), that is NEP to GPP ratio, and CUEclimax, where GPP is derived from the climate conditions. We implemented a non-linear regression analysis in order to identify the best model representing the C flux patterns with stand age. Furthermore, we showed that each C flux have a non-linear relationship with stand age, annual precipitation (P) and mean annual temperature (MAT), therefore, we proposed to use non-linear transformations of the covariates for C fluxes'estimates. Non-linear stand age and climate models were, therefore, used to establish multiple linear regressions for C flux predictions and for determining the contribution of stand age and climate in forest carbon recovery. Our findings depicted that a coupled stand age-climate model explained 33% (44%, average site), 62% (76%, average site), 56% (71%, average site), 41% (59%, average site), 50% (65%, average site) and 36% (50%, average site) of the variance of annual NEP, GPP, Re, photosynthetic respiratory ratio, CUE and CUEclimax across sites, respectively. In addition, we showed that gross fluxes (e.g. GPP and Re) are

  5. Sensitivity of boreal forest carbon balance to soil thaw

    Science.gov (United States)

    Goulden, M.L.; Wofsy, S.C.; Harden, J.W.; Trumbore, S.E.; Crill, P.M.; Gower, S.T.; Fries, T.; Daube, B.C.; Fan, S.-M.; Sutton, D.J.; Bazzaz, A.; Munger, J.W.

    1998-01-01

    We used eddy covariance; gas-exchange chambers; radiocarbon analysis; wood, moss, and soil inventories; and laboratory incubations to measure the carbon balance of a 120-year-old black spruce forest in Manitoba, Canada. The site lost 0.3 ?? 0.5 metric ton of carbon per hectare per year (ton C ha-1 year-1) from 1994 to 1997, with a gain of 0.6 ?? 0.2 ton C ha-1 year-1 in moss and wood offset by a loss of 0.8 ?? 0.5 ton C ha-1 year-1 from the soil. The soil remained frozen most of the year, and the decomposition of organic matter in the soil increased 10-fold upon thawing. The stability of the soil carbon pool (~150 tons C ha-1) appears sensitive to the depth and duration of thaw, and climatic changes that promote thaw are likely to cause a net efflux of carbon dioxide from the site.

  6. Arctic Browning: vegetation damage and implications for carbon balance.

    Science.gov (United States)

    Treharne, Rachael; Bjerke, Jarle; Emberson, Lisa; Tømmervik, Hans; Phoenix, Gareth

    2016-04-01

    'Arctic browning' is the loss of biomass and canopy in Arctic ecosystems. This process is often driven by climatic and biological extreme events - notably extreme winter warm periods, winter frost-drought and severe outbreaks of defoliating insects. Evidence suggests that browning is becoming increasingly frequent and severe at the pan-arctic scale, a view supported by observations from more intensely observed regions, with major and unprecedented vegetation damage reported at landscape (>1000km2) and regional (Nordic Arctic Region) scales in recent years. Critically, the damage caused by these extreme events is in direct opposition to 'Arctic greening', the well-established increase in productivity and shrub abundance observed at high latitudes in response to long-term warming. This opposition creates uncertainty as to future anticipated vegetation change in the Arctic, with implications for Arctic carbon balance. As high latitude ecosystems store around twice as much carbon as the atmosphere, and vegetation impacts are key to determining rates of loss or gain of ecosystem carbon stocks, Arctic browning has the potential to influence the role of these ecosystems in global climate. There is therefore a clear need for a quantitative understanding of the impacts of browning events on key ecosystem carbon fluxes. To address this, field sites were chosen in central and northern Norway and in Svalbard, in areas known to have been affected by either climatic extremes or insect outbreak and subsequent browning in the past four years. Sites were chosen along a latitudinal gradient to capture both conditions already causing vegetation browning throughout the Norwegian Arctic, and conditions currently common at lower latitudes which are likely to become more damaging further North as climate change progresses. At each site the response of Net Ecosystem CO2 Exchange to light was measured using a LiCor LI6400 Portable Photosynthesis system and a custom vegetation chamber with

  7. CERN balances linear collider studies

    CERN Multimedia

    ILC Newsline

    2011-01-01

    The forces behind the two most mature proposals for a next-generation collider, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) study, have been steadily coming together, with scientists from both communities sharing ideas and information across the technology divide. In a support of cooperation between the two, CERN in Switzerland, where most CLIC research takes place, recently converted the project-specific position of CLIC Study Leader to the concept-based Linear Collider Study Leader.   The scientist who now holds this position, Steinar Stapnes, is charged with making the linear collider a viable option for CERN’s future, one that could include either CLIC or the ILC. The transition to more involve the ILC must be gradual, he said, and the redefinition of his post is a good start. Though not very much involved with superconducting radiofrequency (SRF) technology, where ILC researchers have made significant advances, CERN participates in many aspect...

  8. Carbon balance for different management practices for fast growing tree species planted on former pastureland in southern Europe: a case study using the CO2 Fix model

    NARCIS (Netherlands)

    Pérez-Crusado, C.; Mohren, G.M.J.; Merino, A.; Rodríguez-Soalleiro, R.

    2012-01-01

    Although it is known that forestry mitigates carbon emissions to some degree, there is still a need to investigate the extent to which changes in forest management regimes affect the carbon cycle. In a climate-change scenario, forest management schemes must be optimized to maximize product supply an

  9. Study on the Balance Between Carbon Source/Sink and Ecological Surplus Using CASA Model in Yulin%基于CASA模型的榆林碳源/汇平衡与生态盈余研究

    Institute of Scientific and Technical Information of China (English)

    张艳芳; 朱妮

    2013-01-01

    [Objective]From the perspective of ecological balance, this paper mainly studied the influences and mechanism of carbon source and sink and its ecological effect under the 'Grain for Green Project ' and the key base construction of energy and chemical industry in Yulin so as to provide a scientific basis for reduction of carbon emission and increase of carbon sink.[Method]The estimation and analysis in this paper are based on carbon emission model, CASA model, carbon sequestration and oxygen release model as well as energy consumption statistics, MODIS-NDVI, meteorological data, etc.. [Result] Carbon emission of fossil energy consumption increased significantly in Yulin, with a cumulative emission of 8 576.66 104t from 2005 to 2009. Raw coal consumption was the main carbon source. The total carbon emission in Shenmu, Fugu and Yuyang counties accounted for more than 95%of the whole area. The mean value of NPP (net primary productivity, NPP) increased slightly at the average speed of 6 gC·m-2 each year from 2005 to 2009. NPP of Jiaxian, Mizhi and Zizhou counties grew significantly. The mean value of NPP showed a pattern of higher in the south and east, while lower in north and west and the regions which had lower value of NPP centered around Yuyang from northeast to southwest. The amount of CO2 fixed by vegetation was 11 429.3×104 t in Yulin from 2005 to 2009. Overall, the amount of carbon fixation was greater than that of carbon emission in Yulin from 2005 to 2009 and the differences would increase year by year, showing an increasing tendency of ecological surplus levels. Meanwhile, the balance between carbon source and sink and its ecological surplus displayed significant space differences. Shenmu, Fugu and Yuyang counties were the major areas of reducing carbon emission and increasing carbon sink and its ecological surplus level fluctuated significantly and ecological state declined year by year.[Conclusion]The“Grain for Green Project”would help to increase

  10. Century-scale patterns and trends of global pyrogenic carbon emissions and fire influences on terrestrial carbon balance

    Science.gov (United States)

    Yang, Jia; Tian, Hanqin; Tao, Bo; Ren, Wei; Lu, Chaoqun; Pan, Shufen; Wang, Yuhang; Liu, Yongqiang

    2015-09-01

    Fires have consumed a large amount of terrestrial organic carbon and significantly influenced terrestrial ecosystems and the physical climate system over the past century. Although biomass burning has been widely investigated at a global level in recent decades via satellite observations, less work has been conducted to examine the century-scale changes in global fire regimes and fire influences on the terrestrial carbon balance. In this study, we investigated global pyrogenic carbon emissions and fire influences on the terrestrial carbon fluxes from 1901 to 2010 by using a process-based land ecosystem model. Our results show a significant declining trend in global pyrogenic carbon emissions between the early 20th century and the mid-1980s but a significant upward trend between the mid-1980s and the 2000s as a result of more frequent fires in ecosystems with high carbon storage, such as peatlands and tropical forests. Over the past 110 years, average pyrogenic carbon emissions were estimated to be 2.43 Pg C yr-1 (1 Pg = 1015 g), and global average combustion rate (defined as carbon emissions per unit area burned) was 537.85 g C m-2 burned area. Due to the impacts of fires, the net primary productivity and carbon sink of global terrestrial ecosystems were reduced by 4.14 Pg C yr-1 and 0.57 Pg C yr-1, respectively. Our study suggests that special attention should be paid to fire activities in the peatlands and tropical forests in the future. Practical management strategies, such as minimizing forest logging and reducing the rate of cropland expansion in the humid regions, are in need to reduce fire risk and mitigate fire-induced greenhouse gases emissions.

  11. Improving Balance in Subacute Stroke Patients: A Randomized Controlled Study

    Science.gov (United States)

    Goljar, Nika; Burger, Helena; Rudolf, Marko; Stanonik, Irena

    2010-01-01

    The aim of the study was to compare the efficacy of balance training in a balance trainer, a newly developed mechanical device for training balance, with conventional balance training in subacute stroke patients. This was a randomized controlled study. Fifty participants met the inclusion criteria and 39 finished the study. The participants were…

  12. BALANCE

    Science.gov (United States)

    Carmichael, H.

    1953-01-01

    A torsional-type analytical balance designed to arrive at its equilibrium point more quickly than previous balances is described. In order to prevent external heat sources creating air currents inside the balance casing that would reiard the attainment of equilibrium conditions, a relatively thick casing shaped as an inverted U is placed over the load support arms and the balance beam. This casing is of a metal of good thernnal conductivity characteristics, such as copper or aluminum, in order that heat applied to one portion of the balance is quickly conducted to all other sensitive areas, thus effectively preventing the fornnation of air currents caused by unequal heating of the balance.

  13. Significance of erosion-induced carbon fluxes in the carbon balance of a Mediterranean catchment

    Science.gov (United States)

    Nadeu, Elisabet; de Vente, Joris; Boix-Fayos, Carolina

    2014-05-01

    Large uncertainties surround our knowledge of the processes through which carbon (C) sequestration takes place in terrestrial ecosystems. Nevertheless, terrestrial ecosystems could be capturing up to one fourth of the CO2 that is emitted annually to the atmosphere from the burning of fossil fuels and land use changes. Soils are the third largest C reservoir in the C cycle, storing around 1500 Gt of C. Over the last decades, geomorphologists and soil scientists have claimed the role of soil erosion within the C cycle and its potential contribution to the terrestrial C sink. In order to assess the impact of soil erosion on the C cycle, however, an understanding and quantification of the impact of soil erosion on soil C stocks is needed. This implies quantifying lateral and vertical C fluxes associated to detachment, transport and deposition of soil and sediment at different spatial scales. As an example, we present a C budget for a mountainous catchment in south-eastern Spain for a 28 year study period during which the catchment underwent significant land use changes and hydrological correction works (i.e. check-dam construction and reforestations). We quantified lateral C fluxes induced by soil erosion processes and closed a soil/sediment C budget by combining field measurements and numerical modeling. In addition, correlation analysis was conducted between catchment properties (topographic, land use, lithology) and measured C deposition rates to understand the controlling factors on C yield (export) and C concentration in sediments. The results showed that the highest C yields (associated to high sediment yields) were found in subcatchments dominated by soft lithologies and high drainage densities. On the other hand, C concentration in deposited sediments was higher in areas dominated by forest cover, and presented high variability in those parts of the catchment with smoother slopes. Overall, we estimated that around 4000 Mg of C were mobilized from the catchment

  14. An energy balance model of carbon's effect on climate change

    CERN Document Server

    Benney, Lucas

    2015-01-01

    Due to climate change, the interest of studying our climatic system using mathematical modeling has become tremendous in recent years. One well-known model is Budyko's system, which represents the coupled evolution of two variables, the ice-line and the average earth surface temperature. The system depends on natural parameters, such as the earth albedo, and the amount A of carbon in the atmosphere. We introduce a 3-dimensional extension of this model in which we regard A as the third coupled variable of the system. We analyze the phase space and dependence on parameters, looking for Hopf bifurcations and the birth of cycling behavior. We interpret the cycles as climatic oscillations triggered by the sensitivity in our regulation of carbon emissions at extreme temperatures.

  15. Carbon and nutrient use efficiencies optimally balance stoichiometric imbalances

    Science.gov (United States)

    Manzoni, Stefano; Čapek, Petr; Lindahl, Björn; Mooshammer, Maria; Richter, Andreas; Šantrůčková, Hana

    2016-04-01

    Decomposer organisms face large stoichiometric imbalances because their food is generally poor in nutrients compared to the decomposer cellular composition. The presence of excess carbon (C) requires adaptations to utilize nutrients effectively while disposing of or investing excess C. As food composition changes, these adaptations lead to variable C- and nutrient-use efficiencies (defined as the ratios of C and nutrients used for growth over the amounts consumed). For organisms to be ecologically competitive, these changes in efficiencies with resource stoichiometry have to balance advantages and disadvantages in an optimal way. We hypothesize that efficiencies are varied so that community growth rate is optimized along stoichiometric gradients of their resources. Building from previous theories, we predict that maximum growth is achieved when C and nutrients are co-limiting, so that the maximum C-use efficiency is reached, and nutrient release is minimized. This optimality principle is expected to be applicable across terrestrial-aquatic borders, to various elements, and at different trophic levels. While the growth rate maximization hypothesis has been evaluated for consumers and predators, in this contribution we test it for terrestrial and aquatic decomposers degrading resources across wide stoichiometry gradients. The optimality hypothesis predicts constant efficiencies at low substrate C:N and C:P, whereas above a stoichiometric threshold, C-use efficiency declines and nitrogen- and phosphorus-use efficiencies increase up to one. Thus, high resource C:N and C:P lead to low C-use efficiency, but effective retention of nitrogen and phosphorus. Predictions are broadly consistent with efficiency trends in decomposer communities across terrestrial and aquatic ecosystems.

  16. 城市复合生态系统碳氧平衡分析——以沿海城市厦门为例%Analysis of the carbon and oxygen balance of a complex urban ecosystem:A case study in the coastal city of Xiamen

    Institute of Scientific and Technical Information of China (English)

    马巾英; 尹锴; 吝涛

    2011-01-01

    通过综合城市复合生态系统内社会经济活动的主要排碳、耗氧行为,以及城市区域内湿地、淡水、海洋、森林和农田5种遗留自然生态系统的固碳释氧功能,构建了城市碳氧平衡分析模型(UCOB),并估算了城市社会经济活动和城市中自然生态系统的碳氧收支,对城市生态系统平衡状况进行定量化指征.最后,以中国东南沿海城市厦门为例进行研究.结果显示:厦门市2007年碳平衡系数为9.03,即二氧化碳释放量是其所能吸收能力的9.03倍;氧平衡系数为5.78,即社会经济活动消耗的氧气是当地自然生态系统所能提供氧气量的5.78倍.如果不考虑%Through combining the major oxygen consumption and carbon emission of socioeconomic activities and the carbon sequestration and oxygen emission of five remnant natural ecosystems in a complex urban ecosystem,we built an urban carbon and oxygen balance model(UCOB) to estimate the input and output of carbon and oxygen and to quantitatively indicate the ecological balance of an urban ecosystem.The results from a case study of Xiamen,a coastal city in southeastern China,showed:In 2007,the carbon balance index and oxygen balance index of the city were 9.03 and 5.78 respectively,which means the total amount of oxygen consumption and carbon emission from urban socioeconomic activities were 9.03 and 5.78 times greater than the amount of natural oxygen emission and carbon sequestration in Xiamen,respectively.Without considering the indirect oxygen consumption and carbon emission from electricity consumption,the balance indices of carbon and oxygen of Xiamen City were 5.26 and 1.47 respectively.Carbon and oxygen balance indices showed a significant variation among the six administrative districts of Xiamen,because of differences in their socioeconomic functions and distribution of natural ecosystems.As an old industrial zone,Huli district suffered the highest imbalance of carbon and

  17. Hydrology-driven ecosystem respiration determines the carbon balance of a boreal peatland.

    Science.gov (United States)

    Gažovič, Michal; Forbrich, Inke; Jager, Daniel F; Kutzbach, Lars; Wille, Christian; Wilmking, Martin

    2013-10-01

    The carbon (C) balance of boreal peatlands is mainly the sum of three different C fluxes: carbon dioxide (CO2), methane (CH4) and dissolved organic carbon (DOC). Intra- and inter-annual dynamics of these fluxes are differentially controlled by similar factors, such as temperature and water-table. Different climatic conditions within and between years might thus result in varying absolute and relative contributions of each flux to net ecosystem productivity (NEP). In this study CO2 fluxes were measured at a boreal peatland in eastern Finland during a dry year (2006) and a wet year (2007) and combined with DOC and CH4 fluxes from the same site. CO2 uptake in the wet year was 65% higher than in the dry year, caused by higher water table (WT) and subsequently reduced rates of soil respiration. Two to three-fold increases in DOC and CH4 fluxes in the wet year did not completely offset the higher CO2 uptake in that year, resulting in NEP of -83.7±14 g C m(-2) in the dry and -134.5±21 g C m(-2) in the wet year. Thus, in our study, WT was identified as the most important factor responsible for variations in the C balance between the observed years.

  18. Carbon balance of a fertile forestry-drained peatland in southern Finland

    Science.gov (United States)

    Lohila, Annalea; Korkiakoski, Mika; Tuovinen, Juha-Pekka; Minkkinen, Kari; Penttilä, Timo; Ojanen, Paavo; Launiainen, Samuli; Laurila, Tuomas

    2016-04-01

    Forestry on peatlands is a significant land use form and has been economically important during the last decades particularly in the Nordic countries. While nutrient-poor forests are generally able to maintain their carbon sink status even after drainage, the peat soil at the fertile sites is typically considered as a large carbon dioxide (CO2) source. This means that despite of high timber production capacity, the fertile peatland forests gradually lose their peat carbon store. In addition, many of the nutrient-rich sites emit considerable amount of nitrous oxide (N2O) into the atmosphere. While the current estimates of the greenhouse gas (GHG) balance of forestry-drained peatlands are largely based on soil inventories or on data combining soil GHG fluxes and tree growth litter input measurements and modelling, only few studies have utilized the high-resolution, continuous eddy covariance (EC) data to address the short-term dynamics of the net CO2 fluxes covering both the soil, forest floor vegetation and the trees. Hence, little is known about the factors which control the year-to-year variation in fluxes. Here we present a 5-year dataset of CO2 fluxes measured with the EC method above a nutrient-rich forestry-drained peatland in southern Finland. The site, drained in the beginning of 1970's, is a well growing pine forest with some spruces and birches, the tree volume and carbon fixation rate equaling 8.0 kg C m-2 and 0.273 kg C m-2 yr-1, respectively. The average summer-time water level depth is -50 cm. By combining the gap-filled half-hourly net ecosystem exchange (NEE) data, the tree growth measurements, and the measurements on dissolved organic carbon (DOC) losses and soil methane (CH4) exchange, we will in this presentation estimate the total annual loss of peat carbon of this fertile peatland forest. In addition, using the N2O flux data we will estimate the contribution of different gases to the total GHG balance. Factors controlling the carbon balance and

  19. Carbon balance of renovated grasslands: input- or output-driven?

    Science.gov (United States)

    Choncubhair, Órlaith Ní; Osborne, Bruce; Lanigan, Gary

    2015-04-01

    Temperate grasslands constitute over 30% of the Earth's naturally-occurring biomes and make an important contribution towards the partial mitigation of anthropogenic greenhouse gas emissions by terrestrial ecosystems. In permanent temperate grasslands, biomass production and sward quality can deteriorate over time and periodic renovation activities, involving soil tillage and reseeding, are commonly carried out to halt this decline. Long-term cultivation of agricultural land has been associated with soil aggregate degradation and reduced soil carbon storage. However, the impact of these single tillage disturbances on C cycling in grasslands is less clear. This study evaluated gaseous and dissolved organic carbon (DOC) losses following a single tillage event by subjecting grassland lysimeters with contrasting soil drainage characteristics to simulated conventional inversion or minimum tillage. Field-scale CO2 emissions after conventional tillage were also quantified and empirically modelled over short- and medium-term timeframes to delineate the ecosystem response to environmental variables. Soil moisture was the limiting determinant of ecosystem carbon release following conventional tillage. Freshly-tilled soils were associated with reduced water retention and increased sensitivity to soil moisture, which was particularly pronounced following rewetting events. Significantly elevated but ephemeral CO2 effluxes were detected in the hours following inversion ploughing, however tillage disturbance did not generate significantly enhanced C emission rates in the medium term. Equally, DOC losses were not significantly amplified by conventional tillage compared with conservative minimum tillage and were predominantly controlled by soil drainage across tillage regimes. Our results suggest that a net ecosystem source of 120 to 210 g C m-2 over an approximately two-month period was most likely a consequence of reduced productivity and C input rather than enhanced soil CO2

  20. Modelling the role of fires in the terrestrial carbon balance by incorporating SPITFIRE into the global vegetation model ORCHIDEE - Part 2: Carbon emissions and the role of fires in the global carbon balance

    Science.gov (United States)

    Yue, C.; Ciais, P.; Cadule, P.; Thonicke, K.; van Leeuwen, T. T.

    2015-05-01

    Carbon dioxide emissions from wild and anthropogenic fires return the carbon absorbed by plants to the atmosphere, and decrease the sequestration of carbon by land ecosystems. Future climate warming will likely increase the frequency of fire-triggering drought, so that the future terrestrial carbon uptake will depend on how fires respond to altered climate variation. In this study, we modelled the role of fires in the global terrestrial carbon balance for 1901-2012, using the ORCHIDEE global vegetation model equipped with the SPITFIRE model. We conducted two simulations with and without the fire module being activated, using a static land cover. The simulated global fire carbon emissions for 1997-2009 are 2.1 Pg C yr-1, which is close to the 2.0 Pg C yr-1 as estimated by GFED3.1. The simulated land carbon uptake after accounting for emissions for 2003-2012 is 3.1 Pg C yr-1, which is within the uncertainty of the residual carbon sink estimation (2.8 ± 0.8 Pg C yr-1). Fires are found to reduce the terrestrial carbon uptake by 0.32 Pg C yr-1 over 1901-2012, or 20% of the total carbon sink in a world without fire. The fire-induced land sink reduction (SRfire) is significantly correlated with climate variability, with larger sink reduction occurring in warm and dry years, in particular during El Niño events. Our results suggest a "fire respiration partial compensation". During the 10 lowest SRfire years (SRfire = 0.17 Pg C yr-1), fires mainly compensate for the heterotrophic respiration that would occur in a world without fire. By contrast, during the 10 highest SRfire fire years (SRfire = 0.49 Pg C yr-1), fire emissions far exceed their respiration partial compensation and create a larger reduction in terrestrial carbon uptake. Our findings have important implications for the future role of fires in the terrestrial carbon balance, because the capacity of terrestrial ecosystems to sequester carbon will be diminished by future climate change characterized by increased

  1. Modelling the role of fires in the terrestrial carbon balance by incorporating SPITFIRE into the global vegetation model ORCHIDEE – Part 2: Carbon emissions and the role of fires in the global carbon balance

    Directory of Open Access Journals (Sweden)

    C. Yue

    2014-12-01

    Full Text Available Carbon dioxide emissions from wild and anthropogenic fires return the carbon absorbed by plants to the atmosphere, and decrease the sequestration of carbon by land ecosystems. Future climate warming will likely increase the frequency of fire-triggering drought; so that the future terrestrial carbon uptake will depend on how fires respond to altered climate variation. In this study, we modelled the role of fires in the global terrestrial carbon balance for 1901–2012, using the global vegetation model ORCHIDEE equipped with the SPITFIRE model. We conducted two simulations with and without the fire module being activated, with a static land cover. The simulated global fire carbon emissions for 1997–2009 are 2.1 Pg C yr−1, which is close to the 2.0 Pg C yr−1 as given by the GFED3.1 data. The simulated land carbon uptake after accounting for emissions for 2003–2012 is 3.1Pg C yr−1, within the uncertainty of the residual carbon sink estimation (2.8 ± 0.8 Pg C yr−1. Fires are found to reduce the terrestrial carbon uptake by 0.32 Pg C yr−1 over 1901–2012, that is 20% of the total carbon sink in a world without fire. The fire-induced land sink reduction (SRfire is significantly correlated with climate variability, with larger sink reduction occurring in warm and dry years, in particular during El Niño events. Our results suggest a symmetrical "respiration equivalence" by fires. During the ten lowest SRfire years (SRfire = 0.17 Pg C yr−1, fires mainly compensate the heterotrophic respiration that would happen if no fires had occurred. By contrast, during the ten highest SRfire fire years (SRfire = 0.49 Pg C yr−1, fire emissions exceed their "respiration equivalence" and create a substantial reduction in terrestrial carbon uptake. Our finding has important implication for the future role of fires in the terrestrial carbon balance, because the capacity of terrestrial ecosystems to sequester carbon will be diminished by future climate

  2. CO2 and CH4 fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    International Nuclear Information System (INIS)

    Release of CO2 from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO2 efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO2 and CH4 (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO2 under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH4 release was studied. The Holocene history of CO2 sequestration and CH4 emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO2 release from peat. A drought lasting from late May to July caused a 90 g C m2 net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO2 release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m-2a-1 in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m-2a-1 for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants contributed to the total peat CO2 efflux by 10-40 % as root respiration and root

  3. Carbon and greenhouse gas balances in an age-sequence of temperate pine plantations

    Science.gov (United States)

    Peichl, M.; Arain, A. M.; Moore, T. R.; Brodeur, J. J.; Khomik, M.; Ullah, S.; Restrepo-Coupé, N.; McLaren, J.; Pejam, M. R.

    2014-06-01

    This study investigated differences in the magnitude and partitioning of the carbon (C) and greenhouse gas (GHG) balances in an age-sequence of four white pine (Pinus strobus L.) afforestation stands (7, 20, 35 and 70 years old as of 2009) in southern Ontario, Canada. The 4 year (2004-2008) mean annual carbon dioxide (CO2) exchanges, based on biometric and eddy covariance data, were combined with the 2-year means of static chamber measurements of methane (CH4) and nitrous oxide (N2O) fluxes (2006-2007) and dissolved organic carbon (DOC) export below 1 m soil depth (2004-2005). The total ecosystem C pool increased with age from 9 to 160 t C ha-1 across the four stands. Rates of organic matter cycling (i.e. litter-fall and decomposition) were similar among the three older stands. In contrast, considerable differences related to stand age and site quality were observed in the magnitude and partitioning of individual CO2 fluxes showing a peak in production and respiration rates in the middle-age (20 year-old) stand growing on fertile post-agricultural soil. The DOC export accounted for 10% of net ecosystem production (NEP) at the 7 year old stand but < 2% at the three older stands. The GHG balance from the combined exchanges of CO2, CH4 and N2O fluxes was 2.6, 21.6, 13.5 and 4.8 t CO2 eq ha-1 yr-1 for the 7, 20, 35, and 70 year-old stands, respectively. The maximum annual contribution from the combined exchanges of CH4, N2O and DOC to the GHG balance was 8% and 15% in the 7 and 70 year-old stands, respectively, but < 1% in the two highly productive middle-age (20 and 35 year-old) stands. Averaged over the entire age-sequence, the CO2 exchange was the main driver of the GHG balance in these forests. The cumulative CO2 sequestration over the 70 years was estimated at 129 \\unit{t} C and 297 t C ha-1 yr-1 for stands growing on low and high productive sites, respectively. This study highlights the importance of accounting for age and site quality effects on forest C and

  4. Carbon and greenhouse gas balances in an age sequence of temperate pine plantations

    Science.gov (United States)

    Peichl, M.; Arain, A. M.; Moore, T. R.; Brodeur, J. J.; Khomik, M.; Ullah, S.; Restrepo-Coupé, N.; McLaren, J.; Pejam, M. R.

    2014-10-01

    This study investigated differences in the magnitude and partitioning of the carbon (C) and greenhouse gas (GHG) balances in an age sequence of four white pine (Pinus strobus L.) afforestation stands (7, 20, 35 and 70 years old as of 2009) in southern Ontario, Canada. The 4-year (2004-2008) mean annual carbon dioxide (CO2) exchanges, based on biometric and eddy covariance data, were combined with the 2-year means of static chamber measurements of methane (CH4) and nitrous oxide (N2O) fluxes (2006-2007) and dissolved organic carbon (DOC) export below 1 m soil depth (2004-2005). The total ecosystem C pool increased with age from 46 to 197 t C ha-1 across the four stands. Rates of organic matter cycling (i.e. litterfall and decomposition) were similar among the three older stands. In contrast, considerable differences related to stand age and site quality were observed in the magnitude and partitioning of individual CO2 fluxes, showing a peak in production and respiration rates in the middle-age (20-year-old) stand growing on fertile post-agricultural soil. The DOC export accounted for 10% of net ecosystem production (NEP) at the 7-year-old stand but <2% at the three older stands. The GHG balance from the combined exchanges of CO2, CH4 and N2O was 2.6, 21.6, 13.5 and 4.8 t CO2 equivalent ha-1 year-1 for the 7-, 20-, 35- and 70-year-old stands, respectively. The maximum annual contribution from the combined exchanges of CH4 and N2O to the GHG balance was 13 and 8% in the 7- and 70-year-old stands, respectively, but <1% in the two highly productive middle-age (20- and 35-year-old) stands. Averaged over the entire age sequence, the CO2 exchange was the main driver of the GHG balance in these forests. The cumulative CO2 sequestration over the 70 years was estimated at 129 t C and 297 t C ha-1 year-1 for stands growing on low- and high-productivity sites, respectively. This study highlights the importance of accounting for age and site quality effects on forest C and GHG

  5. The Energy Balance Study: The Design and Baseline Results for a Longitudinal Study of Energy Balance

    Science.gov (United States)

    Hand, Gregory A.; Shook, Robin P.; Paluch, Amanda E.; Baruth, Meghan; Crowley, E. Patrick; Jaggers, Jason R.; Prasad, Vivek K.; Hurley, Thomas G.; Hebert, James R.; O'Connor, Daniel P.; Archer, Edward; Burgess, Stephanie; Blair, Steven N.

    2013-01-01

    Purpose: The Energy Balance Study (EBS) was a comprehensive study designed to determine over a period of 12 months the associations of caloric intake and energy expenditure on changes in body weight and composition in a population of healthy men and women. Method: EBS recruited men and women aged 21 to 35 years with a body mass index between 20…

  6. Brazilian environmental legislation and scenarios for carbon balance in Areas of Permanent Preservation (APP) in dairy livestock regions

    Science.gov (United States)

    Hott, M. C.; Fonseca, L. D.; Andrade, R. G.

    2011-12-01

    The present study aimed at mapping some categories of Areas of Permanent Preservation (APP) for natural regeneration of semideciduous forests in the regions of Zona da Mata and Campo das Vertentes, Minas Gerais State (Figure 1), and from this to establish what impact the deployment of APP over area of pastures and subsequently milk production and carbon sequestration, considering areas of pasture as one of major factors for the dairy farming in the regions concerned. From the altimetric information from MDE, it was possible to extract morphological and morphometrical data to estimate the areas of APP. We used imagery of MODIS/Terra for extraction of the pastures areas from the vegetation index data NDVI to intersect with the estimated area of APP. In a linear or deterministic scenario of deployment of APPs over in the pasture areas considering that wich are proportionately responsible for sizing the herd, and thus for the milk production in extensive livestock, despite the existence of numerous other factors, there would be an impact 12% in the production of Campo das Vertentes region and 21.5% for the Zona da Mata. In this scenario, according to the carbon balance of forests and livestock, there would be a positive balance with the deployment of areas of permanent preservation and, subsequent promotion of natural regeneration. Considering the current grazing area of the Zona da Mata and Campo das Vertentes, 1.6 million hectares, with the carbon balance estimated at 1 ton/hectare/year, 300,000 hectares would have a balance of 5 ton/hectare/year in whole cycle of 40 years, totaling 200 tons carbon by hectare, or additional 48 million tons fixed, considering 4 tons more than pastures in the case of semideciduous forest. At the end of the cycle or forest climax, there would still be positive carbon balance, estimated as a balance of 2 ton/hectare/year. However, despite the higher carbon balance for the semideciduous forest, compared to livestock, it is important to

  7. Carbon balance indicates a time limit for cultivation of organic soils in central Switzerland

    Science.gov (United States)

    Paul, Sonja; Ammann, Christof; Alewell, Christine; Leifeld, Jens

    2016-04-01

    Peatlands serve as important carbon sinks. Globally, more than 30% of the soil organic carbon is stored in organic soils, although they cover only 3% of the land surface. The agricultural use of organic soils usually requires drainage thereby transforming these soils from a net carbon sink into a net source. Currently, about 2 to 3 Gt CO2 are emitted world-wide from degrading organic soils (Joosten 2011; Parish et al. 2008) which is ca. 5% of the total anthropogenic emissions. Besides these CO2 emissions, the resulting subsidence of drained peat soils during agricultural use requires that drainage system are periodically renewed and finally to use pumping systems after progressive subsidence. In Switzerland, the Seeland region is characterised by fens which are intensively used for agriculture since 1900. The organic layer is degrading and subsequently getting shallower and the underlying mineral soil, as lake marl or loam, is approaching the surface. The questions arises for how long and under which land use practises and costs these soils can be cultivated in the near future. The study site was under crop rotation until 2009 when it was converted to extensively used grassland with the water regime still being regulated. The soil is characterised by a degraded organic horizon of 40 to 70 cm. Since December 2014 we are measuring the carbon exchange of this grassland using the Eddy-Covariance method. For 2015, the carbon balance indicates that the degraded fen is a strong carbon source, with approximately 500 g C m‑2 a‑1. The carbon balance is dominated by CO2 emissions and harvest. Methane emissions are negligible. With the gained emission factors different future scenarios are evaluated for the current cultivation practise of organic soils in central Switzerland. Joosten, H., 2011: Neues Geld aus alten Mooren: Über die Erzeugung von Kohlenstoffzertifikaten aus Moorwiedervernässungen. Telma Beiheft 4, 183-202. Parish, F., A. Sirin, D. Charman, H. Joosten, T

  8. Carbon balance indicates a time limit for cultivation of organic soils in central Switzerland

    Science.gov (United States)

    Paul, Sonja; Ammann, Christof; Alewell, Christine; Leifeld, Jens

    2016-04-01

    Peatlands serve as important carbon sinks. Globally, more than 30% of the soil organic carbon is stored in organic soils, although they cover only 3% of the land surface. The agricultural use of organic soils usually requires drainage thereby transforming these soils from a net carbon sink into a net source. Currently, about 2 to 3 Gt CO2 are emitted world-wide from degrading organic soils (Joosten 2011; Parish et al. 2008) which is ca. 5% of the total anthropogenic emissions. Besides these CO2 emissions, the resulting subsidence of drained peat soils during agricultural use requires that drainage system are periodically renewed and finally to use pumping systems after progressive subsidence. In Switzerland, the Seeland region is characterised by fens which are intensively used for agriculture since 1900. The organic layer is degrading and subsequently getting shallower and the underlying mineral soil, as lake marl or loam, is approaching the surface. The questions arises for how long and under which land use practises and costs these soils can be cultivated in the near future. The study site was under crop rotation until 2009 when it was converted to extensively used grassland with the water regime still being regulated. The soil is characterised by a degraded organic horizon of 40 to 70 cm. Since December 2014 we are measuring the carbon exchange of this grassland using the Eddy-Covariance method. For 2015, the carbon balance indicates that the degraded fen is a strong carbon source, with approximately 500 g C m-2 a-1. The carbon balance is dominated by CO2 emissions and harvest. Methane emissions are negligible. With the gained emission factors different future scenarios are evaluated for the current cultivation practise of organic soils in central Switzerland. Joosten, H., 2011: Neues Geld aus alten Mooren: Über die Erzeugung von Kohlenstoffzertifikaten aus Moorwiedervernässungen. Telma Beiheft 4, 183-202. Parish, F., A. Sirin, D. Charman, H. Joosten, T

  9. Carbon and greenhouse gas balances in an age-sequence of temperate pine plantations

    Directory of Open Access Journals (Sweden)

    M. Peichl

    2014-06-01

    Full Text Available This study investigated differences in the magnitude and partitioning of the carbon (C and greenhouse gas (GHG balances in an age-sequence of four white pine (Pinus strobus L. afforestation stands (7, 20, 35 and 70 years old as of 2009 in southern Ontario, Canada. The 4 year (2004–2008 mean annual carbon dioxide (CO2 exchanges, based on biometric and eddy covariance data, were combined with the 2-year means of static chamber measurements of methane (CH4 and nitrous oxide (N2O fluxes (2006–2007 and dissolved organic carbon (DOC export below 1 m soil depth (2004–2005. The total ecosystem C pool increased with age from 9 to 160 t C ha−1 across the four stands. Rates of organic matter cycling (i.e. litter-fall and decomposition were similar among the three older stands. In contrast, considerable differences related to stand age and site quality were observed in the magnitude and partitioning of individual CO2 fluxes showing a peak in production and respiration rates in the middle-age (20 year-old stand growing on fertile post-agricultural soil. The DOC export accounted for 10% of net ecosystem production (NEP at the 7 year old stand but 2, CH4 and N2O fluxes was 2.6, 21.6, 13.5 and 4.8 t CO2 eq ha−1 yr−1 for the 7, 20, 35, and 70 year-old stands, respectively. The maximum annual contribution from the combined exchanges of CH4, N2O and DOC to the GHG balance was 8% and 15% in the 7 and 70 year-old stands, respectively, but 2 exchange was the main driver of the GHG balance in these forests. The cumulative CO2 sequestration over the 70 years was estimated at 129 \\unit{t} C and 297 t C ha−1 yr−1 for stands growing on low and high productive sites, respectively. This study highlights the importance of accounting for age and site quality effects on forest C and GHG balances. It further demonstrates a large potential for C sequestration and climate benefits (i.e. cooling effect gained through afforestation of marginal agricultural and

  10. The oxygen and carbon dioxide balance in the earth's atmosphere

    Science.gov (United States)

    Johnson, F. S.

    1975-01-01

    The oxygen-carbon dioxide cycle is described in detail, and steps which are sensitive to perturbation or instability are identified. About half of the carbon dioxide consumption each year in photosynthesis occurs in the oceans. Phytoplankton, which are the primary producers, have been shown to assimilate insecticides and herbicides. The impact of such materials on phytoplankton photosynthesis, both direct and as the indirect result of detrimental effects higher up in the food chain, cannot be assessed. Net oxygen production is very small in comparison with the total production and occurs almost exclusively in a few ocean areas with anoxic bottom conditions and in peat-forming marshes which are sensitive to anthropogenic disturbances. The carbon dioxide content of the atmosphere is increasing at a relatively rapid rate as the result of fossil fuel combustion. Increases in photosynthesis as the result of the hothouse effect may in turn reduce the carbon dioxide content of the atmosphere, leading to global cooling.

  11. Carbon and nitrogen balances for six shrublands across Europe

    DEFF Research Database (Denmark)

    Beier, Claus; Emmett, Bridget A.; Tietema, Albert;

    2009-01-01

    Shrublands constitute significant and important parts of European landscapes providing a large number of important ecosystem services. Biogeochemical cycles in these ecosystems have gained little attention relative to forests and grassland systems, but data on such cycles are required...... for developing and testing ecosystem models. As climate change progresses, the potential feedback from terrestrial ecosystems to the atmosphere through changes in carbon stocks, carbon sequestration, and general knowledge on biogeochemical cycles becomes increasingly important. Here we present carbon...... that in the future a climate-driven land cover change between grasslands and shrublands in Europe will likely lead to increased ecosystem C where shrublands are promoted and less where grasses are promoted. However, it also emphasizes that if feedbacks on the global carbon cycle are to be predicted it is critically...

  12. Effects of simulated drought on the carbon balance of Everglades short-hydroperiod marsh.

    Science.gov (United States)

    Malone, Sparkle L; Starr, Gregory; Staudhammer, Christina L; Ryan, Michael G

    2013-08-01

    Hydrology drives the carbon balance of wetlands by controlling the uptake and release of CO2 and CH4 . Longer dry periods in between heavier precipitation events predicted for the Everglades region, may alter the stability of large carbon pools in this wetland's ecosystems. To determine the effects of drought on CO2 fluxes and CH4 emissions, we simulated changes in hydroperiod with three scenarios that differed in the onset rate of drought (gradual, intermediate, and rapid transition into drought) on 18 freshwater wetland monoliths collected from an Everglades short-hydroperiod marsh. Simulated drought, regardless of the onset rate, resulted in higher net CO2 losses net ecosystem exchange (NEE) over the 22-week manipulation. Drought caused extensive vegetation dieback, increased ecosystem respiration (Reco ), and reduced carbon uptake gross ecosystem exchange (GEE). Photosynthetic potential measured by reflective indices (photochemical reflectance index, water index, normalized phaeophytinization index, and the normalized difference vegetation index) indicated that water stress limited GEE and inhibited Reco . As a result of drought-induced dieback, NEE did not offset methane production during periods of inundation. The average ratio of net CH4 to NEE over the study period was 0.06, surpassing the 100-year greenhouse warming compensation point for CH4 (0.04). Drought-induced diebacks of sawgrass (C3 ) led to the establishment of the invasive species torpedograss (C4 ) when water was resupplied. These changes in the structure and function indicate that freshwater marsh ecosystems can become a net source of CO2 and CH4 to the atmosphere, even following an extended drought. Future changes in precipitation patterns and drought occurrence/duration can change the carbon storage capacity of freshwater marshes from sinks to sources of carbon to the atmosphere. Therefore, climate change will impact the carbon storage capacity of freshwater marshes by influencing water

  13. Stress differentially impacts reserve pools and root exudation: implications for ecosystem functioning and carbon balance

    Science.gov (United States)

    Landhäusser, Simon; Karst, Justine; Wiley, Erin; Gaster, Jacob

    2016-04-01

    Environmental stress can influence carbon assimilation and the accumulation and distribution of carbon between growth, reserves, and exudation; however, it is unclear how these processes vary by different stress types. Partitioning of carbon to growth and reserves in plants might also vary between different organs. Roots reserves are of particular interest as they link the plant with the soil carbon cycle through exudation. Simple models of diffusion across concentration gradients predict the more C reserves in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by the plants. In a controlled study we tested whether different types of stresses (shade, cold soil, and drought) have differential effects on the distribution, abundance, and form (sugar vs. starch) of carbohydrates in seedlings, and whether these changes alone could explain differences in root exudation between stress types. Non-structural carbohydrate (NSC) concentration and pool sizes varied by stress type and between organs. Mass-specific C exudation increased with fine root sugar concentration; however, stress type affected exudation independently of reserve concentration. Seedlings exposed to cold soils exuded the most C on a per root mass basis followed by shade and drought. Through 13C labeling, we also found that depending on the stress type, aspen seedlings may be less able to control the loss of C to the soil compared with unstressed seedlings, resulting in more C leaked to the rhizosphere. The loss of C beyond that predicted by simple concentration gradients might have important implications for ecosystem functioning and carbon balance. If stressed plants lose proportionally more carbon to the soil, existing interactions between plants and soils may decouple under stress, and may include unexpected C fluxes between trees, soils and the atmosphere with a changing climate.

  14. Effects of a windthrow disturbance on the carbon balance of a broadleaf deciduous forest in Hokkaido, Japan

    Science.gov (United States)

    Yamanoi, K.; Mizoguchi, Y.; Utsugi, H.

    2015-12-01

    Forests play an important role in the terrestrial carbon balance, with most being in a carbon sequestration stage. The net carbon releases that occur result from forest disturbance, and windthrow is a typical disturbance event affecting the forest carbon balance in eastern Asia. The CO2 flux has been measured using the eddy covariance method in a deciduous broadleaf forest (Japanese white birch, Japanese oak, and castor aralia) in Hokkaido, where incidental damage by the strong Typhoon Songda in 2004 occurred. We also used the biometrical method to demonstrate the CO2 flux within the forest in detail. Damaged trees amounted to 40 % of all trees, and they remained on site where they were not extracted by forest management. Gross primary production (GPP), ecosystem respiration (Re), and net ecosystem production were 1350, 975, and 375 g C m-2 yr-1 before the disturbance and 1262, 1359, and -97 g C m-2 yr-1 2 years after the disturbance, respectively. Before the disturbance, the forest was an evident carbon sink, and it subsequently transformed into a net carbon source. Because of increased light intensity at the forest floor, the leaf area index and biomass of the undergrowth (Sasa kurilensis and S. senanensis) increased by factors of 2.4 and 1.7, respectively, in 3 years subsequent to the disturbance. The photosynthesis of Sasa increased rapidly and contributed to the total GPP after the disturbance. The annual GPP only decreased by 6 % just after the disturbance. On the other hand, the annual Re increased by 39 % mainly because of the decomposition of residual coarse-wood debris. The carbon balance after the disturbance was controlled by the new growth and the decomposition of residues. The forest management, which resulted in the dead trees remaining at the study site, strongly affected the carbon balance over the years. When comparing the carbon uptake efficiency at the study site with that at others, including those with various kinds of disturbances, we

  15. Balancing carbon sequestration and GHG emissions in a constructed wetland

    NARCIS (Netherlands)

    Klein, de J.J.M.; Werf, van der A.K.

    2014-01-01

    In many countries wetlands are constructed or restored for removing nutrients from surface water. At the same time vegetated wetlands can act as carbon sinks when CO2 is sequestered in biomass. However, it is well known that wetlands also produce substantial amounts of greenhouse gasses CH4 and N2O.

  16. Effect of mosaic representation of vegetation in land surface schemes on simulated energy and carbon balances

    Directory of Open Access Journals (Sweden)

    R. Li

    2011-06-01

    Full Text Available Energy and carbon balance implications of representing vegetation using a composite or mosaic approach in a land surface scheme are investigated. In the composite approach the attributes of different plant functional types (PFTs present in a grid cell are aggregated in some fashion for energy and water balance calculations. The resulting physical environmental conditions (including net radiation, soil moisture and soil temperature are common to all PFTs and affect their ecosystem processes. In the mosaic approach energy and water balance calculations are performed separately for each PFT tile using its own vegetation attributes, so each PFT "sees" different physical environmental conditions and its carbon balance evolves somewhat differently from that in the composite approach. Simulations are performed at selected boreal, temperate and tropical locations to illustrate the differences caused by using the composite versus the mosaic approaches of representing vegetation. Differences in grid averaged primary energy fluxes are generally less than 5 % between the two approaches. Grid-averaged carbon fluxes and pool sizes can, however, differ by as much as 46 %. Simulation results suggest that differences in carbon balance between the two approaches arise primarily through differences in net radiation which directly affects net primary productivity, and thus leaf area index and vegetation biomass.

  17. Modelling the carbon and nitrogen balances of direct land use changes from energy crops in Denmark

    DEFF Research Database (Denmark)

    Hamelin, Lorie; Jørgensen, Uffe; Petersen, Bjørn Molt;

    2012-01-01

    rate reductions in response to the absence of tillage for some perennial crops (0%, 25%, 50%). For all crop systems, nutrient balances, balances between above- and below-ground residues, soil carbon changes, biogenic carbon dioxide flows, emissions of nitrogen compounds and losses of macro......This paper addresses the conversion of Danish agricultural land from food/feed crops to energy crops. To this end, a life cycle inventory, which relates the input and output flows from and to the environment of 528 different crop systems, is built and described. This includes seven crops (annuals...

  18. How have past fire disturbances contributed to the current carbon balance of boreal ecosystems?

    Science.gov (United States)

    Yue, C.; Ciais, P.; Zhu, D.; Wang, T.; Peng, S. S.; Piao, S. L.

    2016-02-01

    Boreal fires have immediate effects on regional carbon budgets by emitting CO2 into the atmosphere at the time of burning, but they also have legacy effects by initiating a long-term carbon sink during post-fire vegetation recovery. Quantifying these different effects on the current-day pan-boreal (44-84° N) carbon balance and quantifying relative contributions of legacy sinks by past fires is important for understanding and predicting the carbon dynamics in this region. Here we used the global dynamic vegetation model ORCHIDEE-SPITFIRE (Organising Carbon and Hydrology In Dynamic Ecosystems - SPread and InTensity of FIRE) to attribute the contributions by fires in different decades between 1850 and 2009 to the carbon balance of 2000-2009, taking into account the atmospheric CO2 change and climate change since 1850. The fire module of ORCHIDEE-SPITFIRE was turned off for each decade in turn and was also turned off before and after the decade in question in order to model the legacy carbon trajectory by fires in each past decade. We found that, unsurprisingly, fires that occurred in 2000-2009 are a carbon source (-0.17 Pg C yr-1) for the carbon balance of 2000-2009, whereas fires in all decades before 2000 contribute carbon sinks with a collective contribution of 0.23 Pg C yr-1. This leaves a net fire sink effect of 0.06 Pg C yr-1, or 6.3 % of the simulated regional carbon sink (0.95 Pg C yr-1). Further, fires with an age of 10-40 years (i.e., those that occurred during 1960-1999) contribute more than half of the total sink effect of fires. The small net sink effect of fires indicates that current-day fire emissions are roughly balanced out by legacy sinks. The future role of fires in the regional carbon balance remains uncertain and will depend on whether changes in fires and associated carbon emissions will exceed the enhanced sink effects of previous fires, both being strongly affected by global change.

  19. The role of stream water carbon dynamics and export in the carbon balance of a tropical seasonal rainforest, southwest China.

    Directory of Open Access Journals (Sweden)

    Wen-Jun Zhou

    Full Text Available A two-year study (2009 ~ 2010 was carried out to investigate the dynamics of different carbon (C forms, and the role of stream export in the C balance of a 23.4-ha headwater catchment in a tropical seasonal rainforest at Xishuangbanna (XSBN, southwest China. The seasonal volumetric weighted mean (VWM concentrations of total inorganic C (TIC and dissolved inorganic C (DIC were higher, and particulate inorganic C (PIC and organic C (POC were lower, in the dry season than the rainy season, while the VWM concentrations of total organic C (TOC and dissolved organic C (DOC were similar between seasons. With increased monthly stream discharge and stream water temperature (SWT, only TIC and DIC concentrations decreased significantly. The most important C form in stream export was DIC, accounting for 51.8% of the total C (TC export; DOC, POC, and PIC accounted for 21.8%, 14.9%, and 11.5% of the TC export, respectively. Dynamics of C flux were closely related to stream discharge, with the greatest export during the rainy season. C export in the headwater stream was 47.1 kg C ha(-1 yr(-1, about 2.85% of the annual net ecosystem exchange. This finding indicates that stream export represented a minor contribution to the C balance in this tropical seasonal rainforest.

  20. Pressure balance at the magnetopause: Experimental studies

    OpenAIRE

    Suvorova, A. V.; Dmitriev, A. V.

    2011-01-01

    The pressure balance at the magnetopause is formed by magnetic field and plasma in the magnetosheath, on one side, and inside the magnetosphere, on the other side. In the approach of dipole earth's magnetic field configuration and gas-dynamics solar wind flowing around the magnetosphere, the pressure balance predicts that the magnetopause distance R depends on solar wind dynamic pressure Pd as a power low R ~ Pd^alpha, where the exponent alpha=-1/6. In the real magnetosphere the magnetic file...

  1. Simulating the carbon balance in reclaimed forest ecosystems with the FORECAST model

    Energy Technology Data Exchange (ETDEWEB)

    Welham, C. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Forest Sciences, Forest Ecosystem Simulation Group; ForRx Consulting, Belcarra, BC (Canada); 3GreenTree Ecosystem Services Ltd., Belcarra, BC (Canada)

    2010-07-01

    Large emission sources are beginning to report their carbon footprint on an annual basis as a result of government mandates, shareholder demand for disclosure of a company's risk to climate change, and as part of corporate social responsibility initiatives. Oil sands mining is a carbon intensive activity from the perspective of carbon dioxide emissions. The intensity of carbon emissions can be mitigated through technological and process innovations. However, reclamation is the only mining-related activity that directly removes atmospheric carbon dioxide. This presentation described a modeling exercise that had 3 principal objectives, notably to simulate the carbon balance in a developing reclaimed upland forest ecosystem; to explore the relative change in carbon pools over time; and to compare the carbon balance of the reclaimed ecosystem to its natural analogue. The presentation provided a description of the model and methodology and discussed the simulation protocol. Imperial Oil's Kearl Lake operation, which was used as a test case, showed that approximately 83,000 tonnes of carbon dioxide per hectare can be sequestered per year as a result of reclamation. tabs., figs.

  2. DYNAMICAL BALANCE STUDY OF RING REDUCER

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The basic structure of epicyclical gear transmission with inner teeth of single-ring, double-ring, three-ring and four-ring reducer are analyzed. The force analysis model of ring reducer is built. Following this, it is concluded that the present ring reducers have the problem that the inertia force or the inertia moment is lopsided. On the base of analysis and calculation the balanced ring reducer which can realize the balance of inertia force and inertia moment is brought forward, and so is its concrete realizing step. The specimen of the balanced ring reducer is designed and manufactured; the experiment is carried out on the gear transmission test bench. Compared with other ring reducer of the same power, the balanced ring reducer has many advantages, such as low vibration noise, low cost and less production difficulty and less heat. It is the substitute of other ring reducer of the same kind. Therefore, it has important theoretic significance and highly practical engineering value.

  3. Carbon dioxide balance of subarctic tundra from plot to regional scales

    Directory of Open Access Journals (Sweden)

    M. E. Marushchak

    2012-08-01

    Full Text Available We report here the carbon dioxide (CO2 budget of a 98.6-km2 subarctic tundra area in Northeast European Russia based on measurements at two different scales and two independent up-scaling approaches. Plot scale measurements (chambers on terrestrial surfaces, gas gradient method and bubble collectors on lakes were carried out from July 2007 to October 2008. The landscape scale eddy covariance (EC measurements covered the snow-free period 2008. The annual net ecosystem exchange (NEE of different land cover types ranged from −251 to 84 g C m−2. Leaf area index (LAI was an excellent predictor of the spatial variability in gross photosynthesis (GP, NEE and ecosystem respiration (ER. The plot scale CO2 fluxes were first scaled up to the EC source area and then to the whole study area using two data sets: a land cover classification and a LAI map, both based on field data and 2.4 m pixel-sized Quickbird satellite image. The good agreement of the CO2 balances for the EC footprint based on the different methods (−105 to −81 g C m−2 vs. −79 g C m−2; growing season 2008 justified the integration of the plot scale measurements over the larger area. The annual CO2 balance for the study region was −67 to −41 g C m−2. Due to the heterogeneity of tundra, the effect of climate change on CO2 uptake will vary strongly according to the land cover type and, moreover, likely changes in their relative coverage in future will have great impact on the regional CO2 balance.

  4. Net carbon balance of three full crop rotations at an agricultural site near Gebesee, Germany

    Science.gov (United States)

    Hurkuck, M.; Brümmer, C.; Kolle, O.; Kutsch, W. L.; Moffat, A. M.; Mukwashi, K.; Truckenbrodt, S. C.; Herbst, M.

    2015-12-01

    Continuous eddy-covariance (EC) measurements of biosphere-atmosphere CO2 and H2O exchange have been conducted since 2001 at an agricultural site near Gebesee, Germany, thus providing one of the longest EC time series of European croplands. During the experimental period, winter wheat and winter barley were alternately planted with potatoes, sugar beet, rape, and peppermint covering three full crop rotations (2001-2004, 2005-2009, and 2010-2014). In this study, data of 14 years of net ecosystem CO2 exchange (NEE) and evapotranspiration (E) were re-calculated. Based on these data, we present the net carbon (C) balance (net biome production, NBP) accounting for any additional C input by fertilization and C output by harvest. Further emphasis was placed on the sensitivity of water use efficiency (WUE) and E to climate and crop type. The main aim was to investigate the interannual variability in both NBP and WUE, thus disentangling the impacts of climatic conditions and land management on the net C balance as well as on WUE and E.

  5. European forest carbon balance assessed with inventory based methods - An introduction to a special section

    NARCIS (Netherlands)

    Nabuurs, G.J.; Hengeveld, G.M.; Werf, van der D.C.; Heidema, A.H.

    2010-01-01

    This paper is an introduction to a special section on inventory based methods to assess the European forest carbon balance. The five papers cover ground based as well as remote sensing based methods, and their combinations and novel modeling efforts for the whole of European forests and forest soils

  6. The Impact of a Mild Sub-Critical Hydrothermal Carbonization Pretreatment on Umbila Wood. A Mass and Energy Balance Perspective

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Cuvilas

    2015-03-01

    Full Text Available Over the last years, the pretreatment of biomass as a source of energy has become one of the most important steps of biomass conversion. In this work the effect of a mild subcritical hydrothermal carbonization of a tropical woody biomass was studied. Results indicate considerable change in carbon content from 52.78% to 65.1%, reduction of oxygen content from 41.14% to 28.72% and ash slagging and fouling potential. Even though decarboxylation, decarbonylation and dehydration reactions take place, dehydration is the one that prevails. The mass and energy balance was affected by the treatment conditions than the severity of the treatment.

  7. Dissolved Carbon Flux and Mass Balance From a Wetland-Dominated Karstic Headwater Catchment

    Science.gov (United States)

    Duval, T. P.; Waddington, J. M.; Branfireun, B. A.

    2009-05-01

    The stream-borne dissolved carbon efflux of peatland-draining catchments is dominated by organic carbon, whereas inorganic carbon dominates the flux from calcareous bedrock catchments. The export of dissolved carbon from calcareous bedrock catchments with significant wetland coverage has not previously been determined. This study documents the spatiotemporal variability of dissolved carbon (inorganic + organic) along a headwater stream in southern Ontario, Canada, as it drains three distinct wetland types: a calcareous fen, a riparian cedar swamp, and a cattail marsh. Upon emergence from the groundwater seeps, the spring water contained 28 times more CO2 than in equilibrium with the atmosphere. This supersaturation decreased to just 5 times equilbrium as the stream leaves the catchment through the marsh, representing a decrease in CO2 concentration of 11 mg L-1, lost to the atmosphere as exsolution. The groundwater seeps contained an average of 1.25±0.75 mg L-1 of dissolved organic carbon (DOC) from May to November 2007, one of the driest years on record in the region. At the catchment outlet through the marsh, DOC concentrations were slightly higher and more variable during the same period at 2.27±1.29 mg L-1, as a fall flushing event resulted in concentrations > 7 mg L-1. This DOC concentration is small compared to the 58.72±3.9 mg L-1 of dissolved inorganic carbon (DIC, as bicarbonate ion) contained within the water leaving the catchment. At 0.21 and 0.17 g m-2 d-1 from May-July and August-November 2007, respectively, the DIC dominated the carbon flux out of the watershed, compared with 0.007 and 0.008 g m- 2 d-1 DOC and 0.015 and 0.009 g m-2 d-1 CO2 exsolution during the same period. Results of the 2007 season will be contrasted to the 2008 season, one of the wettest on record. The watershed is underlain by Silurian dolomite that exhibits karst fractures, resulting in a complex subsurface hydrogeology that influences carbon transport and mass balances

  8. Greenhouse gases inventory and carbon balance of two dairy systems obtained from two methane-estimation methods.

    Science.gov (United States)

    Cunha, C S; Lopes, N L; Veloso, C M; Jacovine, L A G; Tomich, T R; Pereira, L G R; Marcondes, M I

    2016-11-15

    The adoption of carbon inventories for dairy farms in tropical countries based on models developed from animals and diets of temperate climates is questionable. Thus, the objectives of this study were to estimate enteric methane (CH4) emissions through the SF6 tracer gas technique and through equations proposed by the Intergovernmental Panel on Climate Change (IPCC) Tier 2 and to calculate the inventory of greenhouse gas (GHG) emissions from two dairy systems. In addition, the carbon balance of these properties was estimated using enteric CH4 emissions obtained using both methodologies. In trial 1, the CH4 emissions were estimated from seven Holstein dairy cattle categories based on the SF6 tracer gas technique and on IPCC equations. The categories used in the study were prepubertal heifers (n=6); pubertal heifers (n=4); pregnant heifers (n=5); high-producing (n=6); medium-producing (n=5); low-producing (n=4) and dry cows (n=5). Enteric methane emission was higher for the category comprising prepubertal heifers when estimated by the equations proposed by the IPCC Tier 2. However, higher CH4 emissions were estimated by the SF6 technique in the categories including medium- and high-producing cows and dry cows. Pubertal heifers, pregnant heifers, and low-producing cows had equal CH4 emissions as estimated by both methods. In trial 2, two dairy farms were monitored for one year to identify all activities that contributed in any way to GHG emissions. The total emission from Farm 1 was 3.21t CO2e/animal/yr, of which 1.63t corresponded to enteric CH4. Farm 2 emitted 3.18t CO2e/animal/yr, with 1.70t of enteric CH4. IPCC estimations can underestimate CH4 emissions from some categories while overestimate others. However, considering the whole property, these discrepancies are offset and we would submit that the equations suggested by the IPCC properly estimate the total CH4 emission and carbon balance of the properties. Thus, the IPCC equations should be utilized with

  9. Greenhouse gases inventory and carbon balance of two dairy systems obtained from two methane-estimation methods.

    Science.gov (United States)

    Cunha, C S; Lopes, N L; Veloso, C M; Jacovine, L A G; Tomich, T R; Pereira, L G R; Marcondes, M I

    2016-11-15

    The adoption of carbon inventories for dairy farms in tropical countries based on models developed from animals and diets of temperate climates is questionable. Thus, the objectives of this study were to estimate enteric methane (CH4) emissions through the SF6 tracer gas technique and through equations proposed by the Intergovernmental Panel on Climate Change (IPCC) Tier 2 and to calculate the inventory of greenhouse gas (GHG) emissions from two dairy systems. In addition, the carbon balance of these properties was estimated using enteric CH4 emissions obtained using both methodologies. In trial 1, the CH4 emissions were estimated from seven Holstein dairy cattle categories based on the SF6 tracer gas technique and on IPCC equations. The categories used in the study were prepubertal heifers (n=6); pubertal heifers (n=4); pregnant heifers (n=5); high-producing (n=6); medium-producing (n=5); low-producing (n=4) and dry cows (n=5). Enteric methane emission was higher for the category comprising prepubertal heifers when estimated by the equations proposed by the IPCC Tier 2. However, higher CH4 emissions were estimated by the SF6 technique in the categories including medium- and high-producing cows and dry cows. Pubertal heifers, pregnant heifers, and low-producing cows had equal CH4 emissions as estimated by both methods. In trial 2, two dairy farms were monitored for one year to identify all activities that contributed in any way to GHG emissions. The total emission from Farm 1 was 3.21t CO2e/animal/yr, of which 1.63t corresponded to enteric CH4. Farm 2 emitted 3.18t CO2e/animal/yr, with 1.70t of enteric CH4. IPCC estimations can underestimate CH4 emissions from some categories while overestimate others. However, considering the whole property, these discrepancies are offset and we would submit that the equations suggested by the IPCC properly estimate the total CH4 emission and carbon balance of the properties. Thus, the IPCC equations should be utilized with

  10. Effect of climate data on simulated carbon and nitrogen balances for Europe

    Science.gov (United States)

    Blanke, Jan Hendrik; Lindeskog, Mats; Lindström, Johan; Lehsten, Veiko

    2016-05-01

    In this study, we systematically assess the spatial variability in carbon and nitrogen balance simulations related to the choice of global circulation models (GCMs), representative concentration pathways (RCPs), spatial resolutions, and the downscaling methods used as calculated with LPJ-GUESS. We employed a complete factorial design and performed 24 simulations for Europe with different climate input data sets and different combinations of these four factors. Our results reveal that the variability in simulated output in Europe is moderate with 35.6%-93.5% of the total variability being common among all combinations of factors. The spatial resolution is the most important factor among the examined factors, explaining 1.5%-10.7% of the total variability followed by GCMs (0.3%-7.6%), RCPs (0%-6.3%), and downscaling methods (0.1%-4.6%). The higher-order interactions effect that captures nonlinear relations between the factors and random effects is pronounced and accounts for 1.6%-45.8% to the total variability. The most distinct hot spots of variability include the mountain ranges in North Scandinavia and the Alps, and the Iberian Peninsula. Based on our findings, we advise to conduct the application of models such as LPJ-GUESS at a reasonably high spatial resolution which is supported by the model structure. There is no notable gain in simulations of ecosystem carbon and nitrogen stocks and fluxes from using regionally downscaled climate in preference to bias-corrected, bilinearly interpolated CMIP5 projections.

  11. Ecosystem carbon balance of temperate forests differing in elevation and nitrogen availability

    OpenAIRE

    Caprez, Riccarda

    2014-01-01

    This PhD thesis addressed the carbon (C) balance of temperate deciduous forests across natural gradients of temperature and nitrogen (N) availability, the major drivers of net primary production (NPP) and the soil C balance. A mean annual temperature difference of 6 K across a 1200 m change in elevation from the Swiss Plateau to the Central Swiss Alps, and the presence or absence of the N2-fixing tree species Alnus glutinosa or Alnus incana within each elevation, offered the framework (1) to ...

  12. Carbon leaching from tropical peat soils and consequences for carbon balances

    Science.gov (United States)

    Rixen, Tim; Baum, Antje; Wit, Francisca; Samiaji, Joko

    2016-07-01

    Drainage and deforestation turned Southeast (SE) Asian peat soils into a globally important CO2 source, because both processes accelerate peat decomposition. Carbon losses through soil leaching have so far not been quantified and the underlying processes have hardly been studied. In this study, we use results derived from nine expeditions to six Sumatran rivers and a mixing model to determine leaching processes in tropical peat soils, which are heavily disturbed by drainage and deforestation. Here we show that a reduced evapotranspiration and the resulting increased freshwater discharge in addition to the supply of labile leaf litter produced by re-growing secondary forests increase leaching of carbon by ~200%. Enhanced freshwater fluxes and leaching of labile leaf litter from secondary vegetation appear to contribute 38% and 62% to the total increase, respectively. Decomposition of leached labile DOC can lead to hypoxic conditions in rivers draining disturbed peatlands. Leaching of the more refractory DOC from peat is an irrecoverable loss of soil that threatens the stability of peat-fringed coasts in SE Asia.

  13. Magnetic suspension and balance system study

    Science.gov (United States)

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.

    1984-01-01

    A compact design for a superconducting magnetic suspension and balance system is developed for a 8 ft. x 8 ft. transonic wind tunnel. The main features of the design are: a compact superconducting solenoid in the suspended airplane model; permanent magnet wings; one common liquid helium dewar for all superconducting coils; efficient new race track coils for roll torques; use of established 11 kA cryostable AC conductor; acceptable AC losses during 10 Hz control even with all steel structure; and a 560 liter/hour helium liquefier. Considerable design simplicity, reduced magnet weights, and reduced heat leak results from using one common dewar which eliminates most heavy steel structure between coils and the suspended model. Operational availability is thought to approach 100% for such magnet systems. The weight and cost of the magnet system is approximately one-third that of previous less compact designs.

  14. Belowground carbon balance and carbon accumulation rate in the successional series of monsoon evergreen broad-leaved forest

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The balance, accumulation rate and temporal dynamics of belowground carbon in the successional series of monsoon evergreen broadleaved forest are obtained in this paper, based on long-term observations to the soil organic matter, input and standing biomass of litter and coarse woody debris, and dissolved organic carbon carried in the hydrological process of subtropical climax forest ecosystem-monsoon evergreen broad-leaved forest, and its two successional forests of natural restoration-coniferous and broad-leaved mixed forest and Pinus massoniana forest, as well as data of root biomass obtained once every five years and respiration measurement of soil, litter and coarse woody debris respiration for 1 year. The major results include: the belowground carbon pools of monsoon evergreen broad-leaved forest, coniferous and broad-leaved mixed forest, and Pinus massoniana forest are 23191 ± 2538 g·m?2, 16889 ± 1936 g·m?2 and 12680 ± 1854 g·m?2, respectively, in 2002. Mean annual carbon accumulation rates of the three forest types during the 24a from 1978 to 2002 are 383 ± 97 g·m?2·a?1, 193 ± 85 g·m?2·a?1 and 213 ± 86 g·m?2·a?1, respectively. The belowground carbon pools in the three forest types keep increasing during the observation period, suggesting that belowground carbon pools are carbon sinks to the atmosphere. There are seasonal variations, namely, they are strong carbon sources from April to June, weak carbon sources from July to September; while they are strong carbon sinks from October to November, weak carbon sinks from December to March.

  15. The carbon balance pivot point of southwestern U.S. semiarid ecosystems: Insights from the 21st century drought

    Science.gov (United States)

    Scott, Russell L.; Biederman, Joel A.; Hamerlynck, Erik P.; Barron-Gafford, Greg A.

    2015-12-01

    Global-scale studies indicate that semiarid regions strongly regulate the terrestrial carbon sink. However, we lack understanding of how climatic shifts, such as decadal drought, impact carbon sequestration across the wide range of structural diversity in semiarid ecosystems. Therefore, we used eddy covariance measurements to quantify how net ecosystem production of carbon dioxide (NEP) differed with relative grass and woody plant abundance over the last decade of drought in four Southwest U.S. ecosystems. We identified a precipitation "pivot point" in the carbon balance for each ecosystem where annual NEP switched from negative to positive. Ecosystems with grass had pivot points closer to the drought period precipitation than the predrought average, making them more likely to be carbon sinks (and a grass-free shrubland, a carbon source) during the current drought. One reason for this is that the grassland located closest to the shrubland supported higher leaf area and photosynthesis at the same water availability. Higher leaf area was associated with a greater proportion of evapotranspiration being transpiration (T/ET), and therefore with higher ecosystem water use efficiency (gross ecosystem photosynthesis/ET). Our findings strongly show that water availability is a primary driver of both gross and net semiarid productivity and illustrate that structural differences may contribute to the speed at which ecosystem carbon cycling adjusts to climatic shifts.

  16. Estimation of Carbon Balance in Young and Mature Stands of Japanese Cedar (Cryptomeria Japonica) Plantation

    Science.gov (United States)

    Lee, M.; Sode, N.; Koizumi, H.

    2006-12-01

    Two-thirds of Japan is covered by forests, and Japanese cedar (Cryptomeria japonica D. Don) plantations occupy approximately 45% of the plantation areas or 20% of total forested area in Japan. Since the 1950s, cedar plantation has been encouraged and managed for timber production. Therefore, it is important to study quantitatively and synthetically the balance of carbon in cedar plantation ecosystems according to forest development. The ecological process-based approach provides a detailed assessment of belowground compartment as one of the major compartment of carbon balance. Carbon net balance (NEP: net ecosystem production) in ecosystems by this approach is determined by the balance between net primary production (NPP) of vegetation and heterotrophic respiration (HR) of soil (NEP= NPP-HR). HR is the difference between total soil respiration (SR) and root respiration (RR) (HR= SR-RR). To estimate the NPP, we used to biometric method by allometric relationships and litter traps. To estimate the SR, we used a chamber system with automatic open and closing for measuring continuous CO2 efflux from soil surface based on an open-flow method (AOCC) and a portable system for measuring leaf photosynthesis attached to a soil chamber (LI-6400). Our object is to examine balance of carbon in ca. 7 y old (young) and 45 y old (mature) stands of Japanese cedar. Our goal of this study is to investigate carbon cycling on a regional scale using ecological process, remote sensing, and climate observation and modeling analysis as part of the 21st COE program {Satellite Ecology}. This presents the initial results obtained by a process-based measurement since 2004. The study region refers to a cool temperate zone, Asia monsoon climate (36° 08'N, 137° 22'E). In the mature stand, Japanese cedar plantation located in about 10km east of Takayama city, central Japan. The ecological-process research plot was established on the middle of a slope (30m×50m) in November 2004. The slope

  17. Effects of climate variability and functional changes on the interannual variation of the carbon balance in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian; van der Linden, Leon; Lasslop, G.;

    2012-01-01

    The net ecosystem exchange of CO2 (NEE) between the atmosphere and a temperate beech forest showed a significant interannual variation (IAV) and a decadal trend of increasing carbon uptake (Pilegaard et al., 2011). The objectives of this study were to evaluate to what extent and at which temporal...... scale, direct climatic variability and changes in ecosystem functional properties regulated the IAV of the carbon balance at this site. Correlation analysis showed that the sensitivity of carbon fluxes to climatic variability was significantly higher at shorter than at longer time scales and changed...... climatic effects from changes in ecosystem functioning (Richardson et al., 2007) by employing the semi empirical model published by Lasslop et al. (2010b). Fitting the model in short moving windows enabled large flexibility to adjust the parameters to the seasonal course of the ecosystem functional state...

  18. Magnetic suspension and balance system advanced study

    Science.gov (United States)

    Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.

    1985-01-01

    An improved compact design for a superconducting magnetic suspension and balance system for an 8 ft. x 8 ft. transonic wind tunnel is developed. The original design of an MSBS in NASA Cr-3802 utilized 14 external superconductive coils and a superconductive solenoid in the airplane test model suspended in a wind tunnel. The improvements are in the following areas: test model solenoid options, dynamic force limits on the model, magnet cooling options, structure and cryogenic designs, power supply specifications, and cost and performance evaluations. The improvements are: MSBS cost reduction of 28%, weight; reduction of 43%, magnet system ampere-meter reduction of 38%, helium liquifier capacity reduction by 33%, magnet system stored energy reduction by 55%, AC loss to liquid helium reduced by 76%, system power supply reduced by 68%, test coil pole strength increased by 19%, wing magnetization increased by 40%, and control frequency limit increased by 200% from 10 Hz to 30 Hz. The improvements are due to: magnetic holmium coil forms in the test model, better rare earth permanent magnets in the wings, fiberglass-epoxy structure replacing stainless steel, better coil configuration, and new saddle roll coil design.

  19. Energy Crops and their Implications on Soil Carbon Sequestration, Surface Energy and Water Balance

    Science.gov (United States)

    Song, Y.; Barman, R.; Jain, A. K.

    2011-12-01

    The quest to meet growing energy demand with low greenhouse gas emissions has increased attention on the potential of existing and advanced biomass energy crops. Potential energy crops include row crops such as corn, and perennial grasses such as switchgrass. However, a massive expansion of bioenergy crops raises many questions such as: how and where to grow energy crops; and what will be the impacts of growing large scale biofuel crops on the terrestrial hydrological cycle, the surface energy budget, soil carbon sequestration and the concurrent effects on the climate system. An integrated modeling system is being developed with in the framework of a land surface model, the Integrated Science Assessment Model (ISAM), and being applied to address these questions.This framework accounts for the biophysical, physiological and biogeochemical systems governing important processes that regulate crop growth including water, energy and nutrient cycles within the soil-plant-atmosphere system. One row crop (Corn) and two energy crops (Switchgrass and Miscanthus) are studied in current framework. Dynamic phenology processes and parameters for simulating each crop have been developed using observed data from a north to south gradient of field trial sites. This study will specifically focus on the agricultural regions in the US and in Europe. The potential productivity of these three crops will be assessed in terms of carbon sequestration, surface energy and water balance and their spatial variability. This study will help to quantify the importance of various environmental aspects towards modeling bioenergy crops and to better understand the spatial and temporal dynamics of bioenergy crop yields.

  20. The ex-ante appraisal carbon-balance tool (EX-ACT)

    OpenAIRE

    Bernoux, M.; Bockel, L.; Branca, G.

    2009-01-01

    Agriculture contributes about 14% of global greenhouse gases per year. Mitigation for the sector is high since abatement options are often cost neutral or even net-profit-positive. The EX-ACT (Ex-ante Appraisal Carbon-balance) tool was developed by three FAO divisions (TCA, TCI and ESA) and aims to measure the impact of agriculture on GHG emissions and carbon sequestration. It consists of a set of Microsoft Excel sheets into which the project designer inserts land use and management practices...

  1. Adaptive Load Balancing: A Study in Multi-Agent Learning

    OpenAIRE

    Schaerf, A.; Shoham, Y; Tennenholtz, M.

    1995-01-01

    We study the process of multi-agent reinforcement learning in the context of load balancing in a distributed system, without use of either central coordination or explicit communication. We first define a precise framework in which to study adaptive load balancing, important features of which are its stochastic nature and the purely local information available to individual agents. Given this framework, we show illuminating results on the interplay between basic adaptive behavior parameters a...

  2. Carbon and greenhouse gas balance of a temperate pine afforestation chronosequence

    Science.gov (United States)

    Peichl, Matthias; Arain, Altaf; Moore, Tim R.; Brodeur, Jason J.; Khomik, Myroslava; Ullah, Sami; Trant, Janelle; Thorne, Robin

    2013-04-01

    We determined the carbon (C) and greenhouse gas (GHG) balance for an age-sequence of four (7, 20, 35, and 70 years old) afforested white pine (Pinus strobus L.) forests in southern Ontario, Canada. The annual net ecosystem production (NEP) derived from biometric and eddy-covariance (EC) data was combined with estimates of the dissolved organic carbon (DOC) export to obtain the annual net ecosystem carbon balance (NECB). Static chamber measurements of methane (CH4) and nitrous oxide (N2O) fluxes were conducted throughout the snow free periods. The average contribution of DOC export to the NECB decreased from 8% at the 7-year old stand to <1% at the three older stands. The combined contribution from exchanges of CH4 and N2O to the global warming potential (GWP) was estimated at 9% in the 7-year old stand and at 5% in the mature 70-year old stand indicating a significant contribution to the GHG balance of temperate pine forests in early and late development stages. In the two middle-aged stands however, this contribution was <1% and integrated over the entire succession period, the GWP of these forests was driven by the CO2 exchange. Furthermore, our results indicate a large potential for net C sequestration through afforestation of marginal agricultural land ranging between 130 t C ha-1 for low-productive stands to 250 t C ha-1 in high productive pine stands over a period of 70 years.

  3. Crop Management Effects on the Energy and Carbon Balances of Maize Stover-Based Ethanol Production

    Directory of Open Access Journals (Sweden)

    Prem Woli

    2014-12-01

    Full Text Available This study was conducted to identify the crop management options—the combinations of various cultivars, irrigation amounts, planting dates, and soils—that would maximize the energy sustainability and eco-friendliness of maize (Zea mays L. stover-based ethanol production systems in the Mississippi Delta. Stover yields simulated with CERES-Maize were used to compute net energy value (NEV and carbon credit balance (CCB, the indicators of sustainability and eco-friendliness of ethanol production, respectively, for various scenarios. As the results showed, deeper soils with higher water holding capacities had larger NEV and CCB values. Both NEV and CCB had sigmoid relationships with irrigation amount and planting date and could be maximized by planting the crop during the optimum planting window. Stover yield had positive effects on NEV and CCB, whereas travel distance had negative. The influence of stover yield was larger than that of travel distance, indicating that increasing feedstock yields should be emphasized over reducing travel distance. The NEV and CCB values indicated that stover-based ethanol production in the Mississippi Delta is sustainable and environmentally friendly. The study demonstrated that the energy sustainability and eco-friendliness of maize stover-based ethanol production could be increased with alternative crop management options.

  4. Carbon balance of an old hemi-boreal pine forest in Southern Estonia determined by different methods

    Science.gov (United States)

    Soosaar, Kaido; Repp, Kalev; Lõhmus, Krista; Uri, Veiko; Rannik, Kaire; Krasnova, Alisa; Ostonen, Ivika; Kukumägi, Mai; Maddison, Martin; Mander, Ülo

    2016-04-01

    The Soontaga Forest Station is located in hemi-boreal 200-years old pine forest (South Estonia; 58o01'N 26o04'E) with a second layer of spruce. The station has the instrumentation to assess the exchange of carbon dioxide (net ecosystem exchange, NEE), soil respiration, tree biomass (above and below ground biomass) and different environmental and meteorological parameters. In this study we quantified carbon balance by analyzing eddy-covariance CO2 flux data (carbon exchange) vs chamber-based measurements (ecosystem respiration) and CO2assimilation (soil and biomass). The annual NEE in this mature coniferous forest was -2.3 t C ha yr‑1, showing a clear diurnal and seasonal trend. During the daytime in summer the forest sequestered CO2, while during the night and late night CO2 emitted from the ecosystem to the atmosphere. Within the growing period, the sequestration of CO2 by plants was greater than soil respiration. Thus, the ecosystem sequestered carbon. Most of the carbon is bound in tree biomass (above and below ground biomass) but as well into soil, while the sequestration in soil increases with stand age. In addition, the biomass of understory, especially belowground litter, is playing essential part in carbon input. A modelling approach of long-term C budget in the Soontaga pine forest is presented.

  5. Contemporary mire net ecosystem carbon balance - controls and susceptibility to change (Invited)

    Science.gov (United States)

    Nilsson, M. B.

    2013-12-01

    In this presentation I will address three main issues: 1 - The relative importance of the component carbon (C) fluxes for the annual mire Net Ecosystem Carbon Balance (NECB); 2 - The importance of gross primary production (GPP) versus ecosystem respiration (Reco) for the annual Net Ecosystem Exchange (NEE) and finally; 3) the degree of consistency or inconsistency in how controlling factors affects NEE of different mire types. The annual mire NECB is made up principally by the biosphere-atmosphere exchange of CO2 (NEE) and CH4 and the runoff C-export. One important research issue is to further understand what controls the relative contribution from the component fluxes to the annual mire NECB. A second important major research issue is to reveal the relative importance of gross photosynthesis (GPP) and ecosystem respiration (Reco) respectively for the annual mire NEE. The relative importance of GPP and Reco respectively for the NECB also encounters the effect of changes in the lengths of the growing season and non-growing season respectively. The general understanding is that the low rate of decomposition constitutes the major control on peat accumulation. There is though growing evidences from estimates of contemporary annual as well as growing season NEE and peat core based estimates of long-term C accumulation that GPP is at least as important for the annual NEE. Finally, I will address the question to what extent different mire types respond differently to controlling e.g. if bogs and fens respond differently. Recent empirical as well as modeling studies indicate that e.g. changes in water table level causes contrasting response in NEE between bogs and fens.

  6. Work-Life Balance: A Study In The Petroleum Industry

    OpenAIRE

    Judy De Villiers; Elize Kotze

    2003-01-01

    A qualitative study was completed to discover how employees of a company in the petroleum industry define and experience the phenomenon of work-life balance, to identify the workplace determinants of work-life imbalance and to elicit some solutions for the problem. It was found that work-life balance is a personal issue that varies across time and situations and the underlying conflict experienced pertains to role overload and role interference. The most significant work-life conflict arises ...

  7. Longitudinal Study Evaluating Postural Balance of Young Athletes.

    Science.gov (United States)

    Steinberg, Nili; Nemet, Dan; Pantanowitz, Michal; Zeev, Aviva; Hallumi, Monder; Sindiani, Mahmood; Meckel, Yoav; Eliakim, Alon

    2016-02-01

    Repeated anaerobic conditions during athletic performance may cause general and local fatigue that result in postural balance deficit. Evidence suggests that improved postural balance during athletic training may decrease the risk for fallings and traumatic injuries among athletes. Twenty athletes (12 girls, 8 boys) and 20 controls (12 girls, 8 boys) ages 10-15 years participated in the current study. All athletes were active in an 8-month physical activity program, 3 times per week for 90 min., specific to basketball, soccer, or athletic training. The control children participated in physical education at school only, with no involvement in organized extracurricular sports. All participants were evaluated for postural balance in three assessments over one year (at 4-mo intervals); the Interactive Balance System machine (Tetrax device) was used to assess balance at three test times (pre-, post-, and 10 min) after a session of a repeated sprint anaerobic test, consisting of 12 × 20 m run starting every 20 sec. The athletes had better postural balance than controls. There were different group patterns of change over the sessions; a significant interaction of session and group indicated that postural balance of the groups differed. The contribution of low sway frequencies (F1) and high sway frequencies (F6) differed between the controls and the athletes group. Results suggested that although athletes had better postural balance, improvement should be encouraged during training over the sessions and seasons, with special awareness of the balance deficit that occurs immediately after anaerobic stress and at the end of the season, to decrease the risk of injuries. PMID:27420320

  8. The impact of sheep grazing on the carbon balance of a peatland.

    Science.gov (United States)

    Worrall, Fred; Clay, Gareth D

    2012-11-01

    Estimates of the greenhouse gas (GHG) fluxes resulting from sheep grazing upon upland peat soils have never been fully quantified. Previous studies have been limited to individual flux pathways or to comparing the presence to the absence of sheep grazing. Therefore, this study combines a model of the physical impact of grazing with models of: biomass production; energy usage in sheep; and peat accumulation. These combined modelling approaches enabled this study to consider the indirect and direct impacts of sheep upon the carbon and greenhouse gas balance of a peatland at different grazing intensities as well as the changes between grazing intensities. The study considered four vegetation scenarios (Calluna sp., Molinia sp.; reseeded grasses, and Agrostis-Festuca grassland) and a mixed vegetation scenario based upon the vegetation typical of upland peat ecosystems in northern England. Each scenario was considered for altitudes between 350 and 900 m above sea level and for grazing intensities between 0.1 and 2 ewes/ha. The study can show that the total GHG flux at the vegetative carrying capacity tended to decline with increasing altitude for all vegetation scenarios considered except for Molinia sp. The average total GHG flux for all scenarios was 1505 kg CO(2)eq/ha/yr/(ewe/ha), and on average 89% of the fluxes were directly from the sheep and not from the soil, and are therefore not unique to a peat soil environment. The study suggests that emission factors for upland sheep have been greatly underestimated. By comparing the total flux due to grazers to the flux to or from the soil that allows the study to define a GHG carry capacity, i.e. the grazing intensity at which the flux due to grazing is equal to the sink represented by the peat soils, this GHG carrying capacity varies between 0.2 and 1.7 ewes/ha with this capacity declining with increasing altitude for all model scenarios. PMID:23026149

  9. Detecting Disturbance and its Impact on Ecosystem Carbon Balance from Global to Regional Scales

    Science.gov (United States)

    Ballantyne, A.; Jacobson, A. R.; Anderegg, W.; Poulter, B.; Cooper, L. A.; Smith, W. K.; Miller, J. B.

    2015-12-01

    One of the most vital ecosystem services currently provided by the terrestrial biosphere is the removal of approximately one quarter of the anthropogenic CO2 emitted to the atmosphere. However, as patterns of temperature and precipitation change so is the frequency and intensity of ecosystem disturbance. Despite evidence that ecosystem disturbance regimes have shifted leading to widespread forest mortality, the net effect of disturbance on the carbon (C) balance of forest ecosystems remains uncertain. We will use satellite and atmospheric observations to deconvolve net carbon exchange (NEE) into its component fluxes of gross primary productivity and total respiration (e.g. NEE= GPP - R) at global to regional scales. At the global scale we find that NEE has increased over the last 50 years and appears to have accelerated as a result of diminished R over the last 15 years. However the variance in global NEE has also increased perhaps due to inter-annual variability in R, especially within semi-arid ecosystems. These global trends are not necessarily consistent with regional patterns in the net carbon balance, especially across the western US. Atmospheric mass balance suggests that ecosystems of North America have shifted from a net C sink to a net C source. While prolonged drought across the Western US has likely caused this shift in continental scale NEE, attributing this shift in the net C balance to any one mechanism of disturbance (e.g. drought, insect infestation, and fire) or their interactions is challenging. Lastly, we will evaluate existing observing networks, such as NOAA/ESRL and Ameriflux, and how they can be combined with nascent networks, such as NEON, EarthNetworks, and OCO-2, to identify regional disturbance processes that may be causing increasing variance in the global C cycle.

  10. Comparison of carbon balance in Mediterranean pilot constructed wetlands vegetated with different C4 plant species.

    Science.gov (United States)

    Barbera, Antonio C; Borin, Maurizio; Cirelli, Giuseppe L; Toscano, Attilio; Maucieri, Carmelo

    2015-02-01

    This study investigates carbon dioxide (CO2) and methane (CH4) emissions and carbon (C) budgets in a horizontal subsurface flow pilot-plant constructed wetland (CW) with beds vegetated with Cyperus papyrus L., Chrysopogon zizanioides (L.) Roberty, and Mischantus × giganteus Greef et Deu in the Mediterranean basin (Sicily) during the 1st year of plant growing season. At the end of the vegetative season, M. giganteus showed the higher biomass accumulation (7.4 kg m(-2)) followed by C. zizanioides (5.3 kg m(-2)) and C. papyrus (1.8 kg m(-2)). Significantly higher emissions of CO2 were detected in the summer, while CH4 emissions were maximum during spring. Cumulative CO2 emissions by C. papyrus and C. zizanioides during the monitoring period showed similar trends with final values of about 775 and 1,074 g m(-2), respectively, whereas M. giganteus emitted 3,395 g m(-2). Cumulative CH4 bed emission showed different trends for the three C4 plant species in which total gas release during the study period was for C. papyrus 12.0 g m(-2) and ten times higher for M. giganteus, while C. zizanioides bed showed the greatest CH4 cumulative emission with 240.3 g m(-2). The wastewater organic carbon abatement determined different C flux in the atmosphere. Gas fluxes were influenced both by plant species and monitored months with an average C-emitted-to-C-removed ratio for C. zizanioides, C. papyrus, and M. giganteus of 0.3, 0.5, and 0.9, respectively. The growing season C balances were positive for all vegetated beds with the highest C sequestered in the bed with M. giganteus (4.26 kg m(-2)) followed by C. zizanioides (3.78 kg m(-2)) and C. papyrus (1.89 kg m(-2)). To our knowledge, this is the first paper that presents preliminary results on CO2 and CH4 emissions from CWs vegetated with C4 plant species in Mediterranean basin during vegetative growth. PMID:24743957

  11. Toward a consistency cross-check of eddy covariance flux–based and biometric estimates of ecosystem carbon balance

    DEFF Research Database (Denmark)

    Luyssaert, S.; Reichstein, M.; Schulze, E.-D.;

    2009-01-01

    Quantification of an ecosystem's carbon balance and its components is pivotal for understanding both ecosystem functioning and global cycling. Several methods are being applied in parallel to estimate the different components of the CO2 balance. However, different methods are subject to different...

  12. Carbon and energy balances for cellulosic biofuel crops in U.S. Midwest

    Science.gov (United States)

    Gerlfand, I.; Hamilton, S. K.; Robertson, G. P.

    2012-04-01

    Cellulosic biofuels produced on lands not used for food production have the potential to avoid competition for food and associated indirect land use costs. Understanding the carbon and energy balance implications for different cellulosic production systems is important for the development of decision making tools and policies. Here we present carbon and energy balances of alternative agricultural management. We use 20 years of data from KBS LTER experiments to produce farm level CO2 and energy balances for different management practices. Our analyses include four grain and four perrenial systems in the U.S. Midwest: corn (Zea mays) - soybean (Glycine max) - wheat (Triticum aestivum) rotations managed with (1) conventional tillage, (2) no till, (3) low chemical input, and (4) biologically-based (organic) practices; (5) continuous alfalfa (Medicago sativa); (6) Poplar; and (7,8) Successionnal fields, both fertilized and unfertilized. Measurements include fluxes of N2O and CH4, soil organic carbon change, agricultural yields, and agricultural inputs (e.g. fertilization and farm fuel use). Our results indicate that management decisions such as tillage and plant types have a great influence on the net carbon and energy balances and benefits of cellulosic biofuels production. Specifically, we show that cellulosic biofuels produced from an early successional, minimally managed system have a net C sequestration (i.e., negative C balance) of -841±46 gCO2e m-2 yr-1 vs. -594±93 gCO2e m-2 yr-1 for more productive and management intensive alfalfa, and vs. 232±157 gCO2e m-2 for poplar. The reference agricultural system (a conventionally tilled corn-soybean-wheat rotation) has net sequestration of -149±33 g CO2e m-2 yr-1. Among the annual grain crops, average energy costs of farming for the different systems ranged from 4.8 GJ ha-1 for the organic system to 7.1 GJ ha-1 for the conventional; the no-till system was also low at 4.9 GJ ha-1 and the low-chemical input system

  13. Carbon balance of a southern taiga spruce stand in European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Milyukova, I.M.; Varlagin, A.V.; Vygodskaya, N.N. [Sukachev' s Laboratory of the Inst. of Evolution and Ecology Problems, Moscow (Russian Federation); Kolle, O.; Schulze, E.D.; Lloyd, J. [Max Planck Inst. for Biogeochemistry, Jena (Germany)

    2002-11-01

    We present results from nearly three years of net ecosystem flux measurements above a boreal spruce stand growing in European Russia. Fluxes were measured by eddy covariance using conventional techniques. In all years examined (1998-2000), the forest was a significant source of carbon to the atmosphere. However, the magnitude of this inferred source depended upon assumptions regarding the degree of 'flux loss' under conditions of low turbulence, such as typically occur at night. When corrections were not made, the forest was calculated to be only a modest source of C to the atmosphere (3-5 mol C/m{sup 2}/yr). However, when the corrections were included, the apparent source was much larger (20-30 mol C/m{sup 2}/yr). Using a simple model to describe the temperature dependencies of ecosystem respiration on air and soil temperatures, about 80% of the night-time flux was inferred to be from soil respiration, with the remainder being attributable to foliage, branches and boles. We used reasonable assumptions to estimate the rate of ecosystem respiration during the day, allowing an estimation of canopy photosynthetic rates and hence the annual Gross Primary Productivity of the ecosystem. For the two full years examined (1999 and 2000), this was estimated at 122 and 130 mol C/m{sup 2}/yr, respectively. This value is similar to estimates for boreal forests in Scandinavia, but substantially higher than has been reported for Canadian or Siberian boreal forests. There was a clear tendency for canopy photosynthetic rates to increase with both light and temperature, but the slope of the temperature response of photosynthesis was less steep that that of ecosystem respiration. Thus, on most warm days in summer the forest was a substantial source of carbon to the atmosphere; with the forest usually being a net sink only on high insolation days where the average daily air temperatures were below about 18 deg C. These data, along with other studies on the current balance of

  14. Contribution of root to soil respiration and carbon balance in disturbed and undisturbed grassland communities, northeast China

    Indian Academy of Sciences (India)

    Wei Wang; Jixun Guo; Takehisa Oikawa

    2007-03-01

    Changes in the composition of plant species induced by grassland degradation may alter soil respiration rates and decrease carbon sequestration; however, few studies in this area have been conducted. We used net primary productivity (NPP), microbial biomass carbon (MBC), and soil organic carbon (SOC) to examine the changes in soil respiration and carbon balance in two Chinese temperate grassland communities dominated by Leymus chinensis (undisturbed community; Community 1) and Puccinellia tenuiflora (degraded community; Community 2), respectively. Soil respiration varied from 2.5 to 11.9 g CO2 m-2 d-1 and from 1.5 to 9.3 g CO2 m-2 d-1, and the contribution of root respiration to total soil respiration from 38% to 76% and from 25% to 72% in Communities 1 and 2, respectively. During the growing season (May–September), soil respiration, shoot biomass, live root biomass, MBC and SOC in Community 2 decreased by 28%, 39%, 45%, 55% and 29%, respectively, compared to those in Community 1. The considerably lower net ecosystem productivity in Community 2 than in Community 1 (104.56 vs. 224.73 g C m-2 yr-1) suggests that the degradation has significantly decreased carbon sequestration of the ecosystems.

  15. Carbon balance assessment of a natural steppe of southern Siberia by multiple constraint approach

    Directory of Open Access Journals (Sweden)

    L. Belelli Marchesini

    2007-01-01

    Full Text Available Steppe ecosystems represent an interesting case in which the assessment of carbon balance may be performed through a cross validation of the eddy covariance measurements against ecological inventory estimates of carbon exchanges (Ehman, 2002; Curtis, 2002.

    Indeed, the widespread presence of ideal conditions for the applicability of the eddy covariance technique, as vast and homogeneous grass vegetation cover over flat terrains (Baldocchi, 2003, make steppes a suitable ground to ensure a constrain to flux estimates with independent methodological approaches.

    We report about the analysis of the carbon cycle of a true steppe ecosystem in southern Siberia during the growing season of 2004 in the framework of the TCOS-Siberia project activities performed by continuous monitoring of CO2 fluxes at ecosystem scale by the eddy covariance method, fortnightly samplings of phytomass, and ingrowth cores extractions for NPP assessment, and weekly measurements of heterotrophic component of soil CO2 effluxes obtained by an experiment of root exclusion.

    The carbon balance of the monitored natural steppe was, according to micrometeorological measurements, a sink of carbon of 151.7± 30.1 gC m−2, cumulated during the growing season from May to September. This result was in agreement with the independent estimate through ecological inventory which yielded a sink of 150.1 gC m−2 although this method was characterized by a large uncertainty (±130% considering the 95% confidence interval of the estimate. Uncertainties in belowground process estimates account for a large part of the error. Thus, in particular efforts to better quantify the dynamics of root biomass (growth and turnover have to be undertaken in order to reduce the uncertainties in the assessment of NPP. This assessment should be preferably based on the application of multiple methods, each one characterized by its own merits and

  16. Simulated Net Ecosystem Carbon Balance of Western US Forests Under Contemporary Climate and Management

    Science.gov (United States)

    Yang, Z.; Law, B. E.; Jones, M. O.

    2015-12-01

    Previous projections of the contemporary forest carbon balance in the western US showed uncertainties associated with impacts of climate extremes and a coarse spatio-temporal resolution implemented over heterogeneous mountain regions. We modified the Community Land Model (CLM) 4.5 to produce 4km resolution forest carbon changes with drought, fire and management in the western US. We parameterized the model with species data using local plant trait observations for 30 species. To quantify uncertainty, we evaluated the model with data from flux sites, inventories and ancillary data in the region. Simulated GPP was lower than the measurements at our AmeriFlux sites by 17-22%. Simulated burned area was generally higher than Landsat observations, suggesting the model overestimates fire emissions with the new fire model. Landsat MTBS data show high severity fire represents only a small portion of the total burnt area (12-14%), and no increasing trend from 1984 to 2011. Moderate severity fire increased ~0.23%/year due to fires in the Sierra Nevada (Law & Waring 2014). Oregon, California, and Washington were a net carbon sink, and net ecosystem carbon balance (NECB) declined in California over the past 15 years, partly due to drought impacts. Fire emissions were a small portion of the regional carbon budget compared with the effect of harvest removals. Fossil fuel emissions in CA are more than 3x that of OR and WA combined, but are lower per capita. We also identified forest regions that are most vulnerable to climate-driven transformations and to evaluate the effects of management strategies on forest NECB. Differences in forest NECB among states are strongly influenced by the extent of drought (drier longer in the SW) and management intensity (higher in the PNW).

  17. Effects of climate variability and functional changes on the interannual variation of the carbon balance in a temperate deciduous forest

    Directory of Open Access Journals (Sweden)

    J. Wu

    2011-09-01

    Full Text Available The net ecosystem exchange of CO2 (NEE between the atmosphere and a beech forest (Sorø, Denmark showed significant interannual variation (IAV over 13 years (1997–2009 of observations. The forest sequestered, on average, 157 g C m−2 yr−1, ranging from a source of 32 to a sink of 344 g C m−2 yr−1 in 1998 and 2008, respectively. The objectives of this study were to evaluate to what extent and at which temporal scale, climatic variability (through direct response and changes in ecosystem functional properties (through biotic response regulated the IAV in the ecosystem carbon balance. To address this question, we performed correlation analysis between the carbon fluxes and climate variables at different time scales. The response of CO2 exchange to climatic variability was significantly higher at short time scales and the limiting factors changed intra-annually. Combinations of climate anomalies in different periods of the year either intensified or attenuated the aggregated ecosystem responses, implying that the changing distribution of climate anomalies, in addition to the average climate change, could have stronger impacts on the ecosystem carbon balance in the future. A semi empirical model was used to estimate a set of parameter time series for each of the 13 years, which was considered to represent the functional properties of the ecosystem. The climate and parameter time series were applied factorially by year to quantify their relative importance for the IAV in carbon flux. At an annual time scale, as much as 77 % of the IAV in NEE could be attributed to the variation in both photosynthesis and respiration related model parameters, indicating a strong influence of functional change. The possible causes for the observed functional change could not be addressed with the available dataset. This demonstrates the need for more targeted experiments, such as long

  18. Assessing wildlife benefits and carbon storage from restored and natural coastal marshes in the Nisqually River Delta: Determining marsh net ecosystem carbon balance

    Science.gov (United States)

    Anderson, Frank; Bergamaschi, Brian; Windham-Myers, Lisamarie; Woo, Isa; De La Cruz, Susan; Drexler, Judith; Byrd, Kristin; Thorne, Karen M.

    2016-01-01

    Working in partnership since 1996, the U.S. Fish and Wildlife Service and the Nisqually Indian Tribe have restored 902 acres of tidally influenced coastal marsh in the Nisqually River Delta (NRD), making it the largest estuary-restoration project in the Pacific Northwest to date. Marsh restoration increases the capacity of the estuary to support a diversity of wildlife species. Restoration also increases carbon (C) production of marsh plant communities that support food webs for wildlife and can help mitigate climate change through long-term C storage in marsh soils.In 2015, an interdisciplinary team of U.S. Geological Survey (USGS) researchers began to study the benefits of carbon for wetland wildlife and storage in the NRD. Our primary goals are (1) to identify the relative importance of the different carbon sources that support juvenile chinook (Oncorhynchus tshawytscha) food webs and contribute to current and historic peat formation, (2) to determine the net ecosystem carbon balance (NECB) in a reference marsh and a restoration marsh site, and (3) to model the sustainability of the reference and restoration marshes under projected sea-level rise conditions along with historical vegetation change. In this fact sheet, we focus on the main C sources and exchanges to determine NECB, including carbon dioxide (CO2) uptake through plant photosynthesis, the loss of CO2 through plant and soil respiration, emissions of methane (CH4), and the lateral movement or leaching loss of C in tidal waters.

  19. Assessing wildlife benefits and carbon storage from restored and natural coastal marshes in the Nisqually River Delta: Determining marsh net ecosystem carbon balance

    Science.gov (United States)

    Anderson, Frank; Bergamaschi, Brian; Windham-Myers, Lisamarie; Woo, Isa; De La Cruz, Susan; Drexler, Judith; Byrd, Kristin; Thorne, Karen M.

    2016-06-24

    Working in partnership since 1996, the U.S. Fish and Wildlife Service and the Nisqually Indian Tribe have restored 902 acres of tidally influenced coastal marsh in the Nisqually River Delta (NRD), making it the largest estuary-restoration project in the Pacific Northwest to date. Marsh restoration increases the capacity of the estuary to support a diversity of wildlife species. Restoration also increases carbon (C) production of marsh plant communities that support food webs for wildlife and can help mitigate climate change through long-term C storage in marsh soils.In 2015, an interdisciplinary team of U.S. Geological Survey (USGS) researchers began to study the benefits of carbon for wetland wildlife and storage in the NRD. Our primary goals are (1) to identify the relative importance of the different carbon sources that support juvenile chinook (Oncorhynchus tshawytscha) food webs and contribute to current and historic peat formation, (2) to determine the net ecosystem carbon balance (NECB) in a reference marsh and a restoration marsh site, and (3) to model the sustainability of the reference and restoration marshes under projected sea-level rise conditions along with historical vegetation change. In this fact sheet, we focus on the main C sources and exchanges to determine NECB, including carbon dioxide (CO2) uptake through plant photosynthesis, the loss of CO2 through plant and soil respiration, emissions of methane (CH4), and the lateral movement or leaching loss of C in tidal waters.

  20. Magnetic suspension and balance system advanced study, 1989 design

    Science.gov (United States)

    Boom, Roger W.; Eyssa, Y. M.; Abdelsalam, Moustafa K.; Mcintosh, Glen E.

    1991-01-01

    The objectives are to experimentally confirm several advanced design concepts on the Magnetic Suspension and Balance Systems (MSBS). The advanced design concepts were identified as potential improvements by Madison Magnetics, Inc. (MMI) during 1984 and 1985 studies of an MSBS utilizing 14 external superconductive coils and a superconductive solenoid in an airplane test model suspended in a wind tunnel. This study confirmed several advanced design concepts on magnetic suspension and balance systems. The 1989 MSBS redesign is based on the results of these experiments. Savings of up to 30 percent in supporting magnet ampere meters and 50 percent in energy stored over the 1985 design were achieved.

  1. Calculating carbon mass balance from unsaturated soil columns treated with CaSO₄₋minerals: test of soil carbon sequestration.

    Science.gov (United States)

    Han, Young-Soo; Tokunaga, Tetsu K

    2014-12-01

    Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260 g C m(-1) infiltrated water (20-120 g C m(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment.

  2. Wind Tunnel Force Balance Calibration Study - Interim Results

    Science.gov (United States)

    Rhew, Ray D.

    2012-01-01

    Wind tunnel force balance calibration is preformed utilizing a variety of different methods and does not have a direct traceable standard such as standards used for most calibration practices (weights, and voltmeters). These different calibration methods and practices include, but are not limited to, the loading schedule, the load application hardware, manual and automatic systems, re-leveling and non-re-leveling. A study of the balance calibration techniques used by NASA was undertaken to develop metrics for reviewing and comparing results using sample calibrations. The study also includes balances of different designs, single and multi-piece. The calibration systems include, the manual, and the automatic that are provided by NASA and its vendors. The results to date will be presented along with the techniques for comparing the results. In addition, future planned calibrations and investigations based on the results will be provided.

  3. Carbon mass-balance modeling and carbon isotope exchange processes in the Curonian Lagoon

    Science.gov (United States)

    Barisevičiūtė, Rūta; Žilius, Mindaugas; Ertürk, Ali; Petkuvienė, Jolita

    2016-04-01

    The Curonian lagoon one of the largest coastal lagoons in Europe is located in the southeastern part of the Baltic Sea and lies along the Baltic coast of Lithuania and the Kaliningrad region of Russia. It is influenced by a discharge of the Nemunas and other smaller rivers and saline water of the Baltic Sea. The narrow (width 0.4 km, deep 8-14 m) Klaipėda Strait is the only way for fresh water run-off and brackish water intrusions. This research is focused on carbon isotope fractionations related with air - water exchange, primary production and organic carbon sedimentation, mineralization and uptake from both marine and terrestrial sources.

  4. Interpreting seasonal changes in the carbon balance of southern Amazonia using measurements of XCO2 and chlorophyll fluorescence from GOSAT

    NARCIS (Netherlands)

    Parazoo, Nicholas C.; Bowman, Kevin; Frankenberg, Christian; Lee, Jung-Eun; Fisher, Joshua B.; Worden, John; Jones, Dylan B. A.; Berry, Joseph; Collatz, G. James; Baker, Ian T.; Jung, Martin; Liu, Junjie; Osterman, Gregory; O'Dell, Chris; Sparks, Athena; Butz, Andre; Guerlet, Sandrine; Yoshida, Yukio; Chen, Huilin; Gerbig, Christoph

    2013-01-01

    Amazon forests exert a major influence on the global carbon cycle, but quantifying the impact is complicated by diverse landscapes and sparse data. Here we examine seasonal carbon balance in southern Amazonia using new measurements of column-averaged dry air mole fraction of CO2 (XCO2) and solar ind

  5. Interactions between nitrogen deposition, land cover conversion, and climate change determine the contemporary carbon balance of Europe

    Directory of Open Access Journals (Sweden)

    G. Churkina

    2010-09-01

    Full Text Available European ecosystems are thought to take up large amounts of carbon, but neither the rate nor the contributions of the underlying processes are well known. In the second half of the 20th century, carbon dioxide concentrations have risen by more that 100 ppm, atmospheric nitrogen deposition has more than doubled, and European mean temperatures were increasing by 0.02 °C yr−1. The extents of forest and grasslands have increased with the respective rates of 5800 km2 yr−1 and 1100 km2 yr−1 as agricultural land has been abandoned at a rate of 7000 km2 yr−1. In this study, we analyze the responses of European land ecosystems to the aforementioned environmental changes using results from four process-based ecosystem models: BIOME-BGC, JULES, ORCHIDEE, and O-CN. The models suggest that European ecosystems sequester carbon at a rate of 56 TgC yr−1 (mean of four models for 1951–2000 with strong interannual variability (±88 TgC yr−1, average across models and substantial inter-model uncertainty (±39 TgC yr−1. Decadal budgets suggest that there has been a continuous increase in the mean net carbon storage of ecosystems from 85 TgC yr−1 in 1980s to 108 TgC yr−1 in 1990s, and to 114 TgC yr−1 in 2000–2007. The physiological effect of rising CO2 in combination with nitrogen deposition and forest re-growth have been identified as the important explanatory factors for this net carbon storage. Changes in the growth of woody vegetation are suggested as an important contributor to the European carbon sink. Simulated ecosystem responses were more consistent for the two models accounting for terrestrial carbon-nitrogen dynamics than for the two models which only accounted for carbon cycling and the effects of land cover change. Studies of the interactions of carbon-nitrogen dynamics with

  6. CO2 exchange and Carbon balance in two grassland sites on eutrophic drained peat soils

    Directory of Open Access Journals (Sweden)

    F. Möller

    2007-05-01

    Full Text Available In this study we investigated the role of intensive and extensive dairy farm practices on CO2 exchange and the carbon balance of peatlands by means of eddy covariance (EC measurements. Year long EC measurements were made in two adjacent farm sites on peat soil in the western part of the Netherlands. One site (Stein is a new meadow bird reserve and is managed predominantly by mowing in June and August. The second site (Oukoop is an intensive dairy farm. Minimum ecosystem flux of the grass sward (range −2 to −34 μmol CO2 m−2 s−1 showed a close and similar linear relationship with Leaf Area Index (LAI; range 1 to 5 except in maturing hay meadows, where minimum ecosystem flux did not decrease further. Apparent quantum yield varied between −0.02 and −0.08 (mean −0.045 μmol CO2 μmol−1 photons at both sites and was significantly correlated with LAI during the growth season. Ecosystem Respiration at 10°C (R10 calculated from the year round data set was 3.47 μmol CO2 m−2 s−1 at Stein and 3.64 μmol CO2 m−2 s−1 at Oukoop. Both sites were a source of carbon in winter and a sink during summer, with net ecosystem exchange varying between 50 to 100 mmol CO2m−2 d−1 in winter to below −400 mmol CO2 m−2 d−1 in summer. Periodically both sites became a source after mowing. Net annual ecosystem exchange (NEE for Stein was −8.4 g C m−2 a−1 and for Oukoop 122.4 g C m−2 a−1, the difference between the sites was mainly due a difference in GEP (101 g C m−2 a−1. However when biomass removal, manure applications and estimates of methane emissions are taken into account, both eutrophic peat meadows are a strong source for C ((462 g C m−2 a−1 and 465 g C m−2 a−1 at Stein and Oukoop, respectively.

  7. The Balance Control of Children with and without Hearing Impairment in Singapore--A Case Study

    Science.gov (United States)

    Jernice, Tan Sing Yee; Nonis, Karen P.; Yi, Chow Jia

    2011-01-01

    The purpose of this study is to compare the balance control of participants with and without HI and also to investigate the effect of a Balance Programme (BP) on their balance control (HI; n = 2, M age = 7 years old). The BP consisted of six practice sessions of 45 minutes each. The Balance Tasks used to assess balance control were static Balance…

  8. Studies of Carbon Nanotubes

    Science.gov (United States)

    Caneba, Gerard T.

    2005-01-01

    The fellowship experience for this summer for 2004 pertains to carbon nanotube coatings for various space-related applications. They involve the following projects: (a) EMI protection films from HiPco-polymers, and (b) Thermal protection nanosilica materials. EMI protection films are targeted to be eventually applied onto casings of laptop computers. These coatings are composites of electrically-conductive SWNTs and compatible polymers. The substrate polymer will be polycarbonate, since computer housings are typically made of carbon composites of this type of polymer. A new experimental copolymer was used last year to generate electrically-conductive and thermal films with HiPco at 50/50 wt/wt composition. This will be one of the possible formulations. Reference films will be base polycarbonate and neat HiPco onto polycarbonate films. Other coating materials that will be tried will be based on HiPco composites with commercial enamels (polyurethane, acrylic, polyester), which could be compatible with the polycarbonate substrate. Nanosilica fibers are planned for possible use as thermal protection tiles on the shuttle orbiter. Right now, microscale silica is used. Going to the nanoscale will increase the surface-volume-per-unit-area of radiative heat dissipation. Nanoscale carbon fibers/nanotubes can be used as templates for the generation of nanosilica. A sol-gel operation is employed for this purpose.

  9. Assessment of climate change impact on SOM balance with the Austrian Carbon Calculator

    Science.gov (United States)

    Franko, Uwe; Gründling, Ralf; Sedy, Katrin; Zethner, Gerhard; Formayer, Herbert

    2015-04-01

    Soil organic matter (SOM) balance depends on climate and climate change due to the impact on SOM turnover conditions as well as on cropping and crop yields. The Austrian Carbon calculator (ACC) is a tool for the comparison of future land use scenarios with the current agriculture in order to identify opportunities to sustain the SOM balance. The ACC can be used in a regional mode as well as in local mode for the assessment of single farm fields. The assessment is based on the concept of Biologic Active Time (BAT). BAT is calculated based on soil data from the Austrian eBod map and climate data for past and future on a 1 km grid. The ACC was implemented for the regions Mühlviertel and Marchfeld. Crop yields are calculated based on statistics from the Austrian agricultural sub regions "Kleinproduktionsgebiet" for the most common crops. The regional scenarios consist of the abundance of crops, the part of nitrogen added as mineral fertilizer and the part of irrigation. The local soil management is calculated based on crop rotations with yields, organic amendments, irrigation and the tillage system (ploughed or not ploughed). The SOM balance is assessed with the reproduction index (REP_IX) that is calculated as the quotient from carbon reproduction (Carbon flux into SOM) and the BAT value. This way REP_IX includes the impact from management as well as from climate. If the future management will not change REP_IX the SOM balance will be the same as well. This methodology helps to adapt the management to future conditions to sustain the current SOM conditions without an absolute assessment if the current SOM state is optimal or not. The regional results of ACC will be made available as thematic maps on the project web site. For local applications farmer can use the tool to analyze their special site conditions and management plans to assess the management options under climate change conditions. The described concept can be improved if reliable information about the

  10. Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

    Science.gov (United States)

    Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

    2016-04-01

    Despite the fact that in Russia cropland's soils carbon loses 9 time higher than forest's soils ones (Stolbovoi, 2002), agroecosystems were not given sufficient attention and most of the papers are devoted to forestry and natural ecosystems. Carbon balance was calculated at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia, for two agroecosystems with different crops from the same crop rotation studied for 2 years. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Vertical fluxes of carbon dioxide were measured with eddy covariance technique, statistical method to measure and calculate turbulent fluxes within atmospheric boundary layers (Burba, 2013). Crop rotation included potato, winter wheat, barley and vetch and oat mix. Two fields of the same crop rotation were studied in 2013-2014. One of the fields (A) was used in 2013 for barley planting (Hordeum vulgare L.). The field B was in 2013 used for planting together vetch (Vicia sativa L.) and oats (Avena sativa L.). Inversely oats and vetch grass mixt was sown in 2014 on field A. Winter wheat was sown on field A in the very beginning of September. On the second field (B) in 2014 winter wheat occurred from under the snow in the phase of tillering, after harvesting it in mid of July, white mustard (Sinapis alba) was sown for green manure. Carbon uptake (NEE negative values) was registered only for the field with winter wheat and white mustard; perhaps because the two crops were cultivated on the field within one growing season. Three other cases showed CO2 emission. Great difference in 82 g C m‑2 per year in NEE between two fields with vetch and oat mix was related to higher difference in grass yields. NEE for barley field was positive during the whole year; considering only the growing season, NEE for barley was 100 g C m‑2 lower and was negative

  11. Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

    Science.gov (United States)

    Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

    2016-04-01

    Despite the fact that in Russia cropland's soils carbon loses 9 time higher than forest's soils ones (Stolbovoi, 2002), agroecosystems were not given sufficient attention and most of the papers are devoted to forestry and natural ecosystems. Carbon balance was calculated at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia, for two agroecosystems with different crops from the same crop rotation studied for 2 years. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Vertical fluxes of carbon dioxide were measured with eddy covariance technique, statistical method to measure and calculate turbulent fluxes within atmospheric boundary layers (Burba, 2013). Crop rotation included potato, winter wheat, barley and vetch and oat mix. Two fields of the same crop rotation were studied in 2013-2014. One of the fields (A) was used in 2013 for barley planting (Hordeum vulgare L.). The field B was in 2013 used for planting together vetch (Vicia sativa L.) and oats (Avena sativa L.). Inversely oats and vetch grass mixt was sown in 2014 on field A. Winter wheat was sown on field A in the very beginning of September. On the second field (B) in 2014 winter wheat occurred from under the snow in the phase of tillering, after harvesting it in mid of July, white mustard (Sinapis alba) was sown for green manure. Carbon uptake (NEE negative values) was registered only for the field with winter wheat and white mustard; perhaps because the two crops were cultivated on the field within one growing season. Three other cases showed CO2 emission. Great difference in 82 g C m-2 per year in NEE between two fields with vetch and oat mix was related to higher difference in grass yields. NEE for barley field was positive during the whole year; considering only the growing season, NEE for barley was 100 g C m-2 lower and was negative. Closed

  12. Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

    Directory of Open Access Journals (Sweden)

    J. Järveoja

    2015-10-01

    Full Text Available Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C and greenhouse gas (GHG exchanges is still limited. The aim of this study was to investigate the impact of contrasting water table levels (WTL on the annual C and GHG balances of restoration treatments with high (Res-H and low (Res-L WTL relative to an unrestored bare peat (BP site. Measurements of carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in Res-H relative to Res-L. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in Res-L compared to Res-H. However, the means of the measured net ecosystem CO2 exchanges (NEE were not significantly different between Res-H and Res-L. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges in Res-H and Res-L, respectively. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, Res-H, Res-L and BP were C sources of 111, 103 and 268 g C m−2 yr−1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha−1 yr−1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments three years following restoration. However, the C and GHG balances in Res-H and Res-L were considerably lower than in BP owing to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative

  13. Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

    Science.gov (United States)

    Järveoja, Järvi; Peichl, Matthias; Maddison, Martin; Soosaar, Kaido; Vellak, Kai; Karofeld, Edgar; Teemusk, Alar; Mander, Ülo

    2016-05-01

    Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting mean water table levels (WTLs) on the annual C and GHG balances of restoration treatments with high (ResH) and low (ResL) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in ResH relative to ResL. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in ResL compared to ResH. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between ResH and ResL. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, ResH, ResL and BP were C sources of 111, 103 and 268 g C m-2 yr-1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha-1 yr-1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments 3 years following restoration. However, the C and GHG balances in ResH and ResL were considerably lower than in BP due to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

  14. The Carbon Balance Pivot Point of Southwestern U.S. Semiarid Ecosystems: Insights From the 21st Century Drought

    Science.gov (United States)

    Scott, R. L.; Biederman, J.; Barron-Gafford, G.; Hamerlynck, E. P.

    2015-12-01

    Global-scale studies indicate that semiarid ecosystems strongly regulate the long-term trend and interannual variability of the terrestrial carbon sink, possibly due to changes in vegetation and an inherent sensitivity to changes in water availability. However, we lack understanding of how climate shifts, such as the ongoing decadal-scale drought in the Southwest US, impact carbon sink functioning in semiarid ecosystems with differing structure. Therefore, we investigated the response of net ecosystem production of carbon dioxide (NEP) to changes in annual water availability in four Southwest US ecosystems varying in relative shrub, tree and grass abundance. Using eddy covariance carbon dioxide and water vapor flux measurements collected over the last drought-impacted decade, we identified a precipitation "pivot point" in the annual carbon balance for each ecosystem type where annual NEP switched from negative to positive. At the three sites with larger amounts of grass, rather than woody plant, cover, pivot points were closer to the drought-period mean annual precipitation (MAP) than MAP over the preceding 30 years, suggesting the carbon pools of these grassier ecosystems have more quickly adjusted to the decadal-scale drought. Current-year water availability, as quantified by evapotranspiration (ET) overwhelmingly drove the response of gross ecosystem photosynthesis (GEP) and respiration (Reco) fluxes. Ecosystem water use efficiency (GEP/ET) increased with water availability and leaf area index, resulting in a more efficient photosynthetic use of water in wetter years and at wetter sites. Grasslands supported a higher leaf area than shrublands at a given water availability, and thus had higher GEP/ET. Differences in GEP/ET were also related to the relative proportion of abiotic evaporation, estimated from the ET intercept in a linear regression of ET and GEP, to total ET at a site, highlighting the importance of ET partitioning for understanding how semiarid

  15. Soils apart from equilibrium – consequences for soil carbon balance modelling

    Directory of Open Access Journals (Sweden)

    T. Wutzler

    2006-10-01

    Full Text Available Many projections of the soil carbon sink or source are based on kinetically defined carbon pool models. Parameters of these models are often determined in a way that the steady state of the model matches observed carbon stocks. The underlying simplifying assumption is that observed carbon stocks are near equilibrium. This assumption is challenged by observations of very old soils that do still accumulate carbon. In this modelling study we explored the consequences of the case where soils are apart from equilibrium. Calculation of equilibrium states of soils that are currently accumulating small amounts of carbon were performed using the Yasso model. It was found that already very small current accumulation rates cause big changes in theoretical equilibrium stocks, which can virtually approach infinity. We conclude that soils that have been disturbed several centuries ago are not in equilibrium but in a transient state because of the slowly ongoing accumulation of the slowest pool. A first consequence is that model calibrations to current carbon stocks that assume equilibrium state, overestimate the decay rate of the slowest pool. A second consequence is that spin-up runs (simulations until equilibrium overestimate stocks of recently disturbed sites. In order to account for these consequences, we propose a transient correction. This correction prescribes a lower decay rate of the slowest pool and accounts for disturbances in the past by decreasing the spin-up-run predicted stocks to match an independent estimate of current soil carbon stocks. Application of this transient correction at a Central European beech forest site with a typical disturbance history resulted in an additional carbon fixation of 5.7±1.5 tC/ha within 100 years. Carbon storage capacity of forest soils is potentially much higher than currently assumed. Simulations that do not adequately account for the transient state of soil carbon stocks neglect a substantial amount of

  16. Static Balance in Patients with Vestibular Impairments: A Preliminary Study

    Science.gov (United States)

    Talebi, Hossein; Abtahi, Seyed Hamid Reza; Fereshtenejad, Niloofar

    2016-01-01

    Aims. Vestibular system is indicated as one of the most important sensors responsible for static and dynamic postural control. In this study, we evaluated static balance in patients with unilateral vestibular impairments. Materials and Methods. We compared static balance control using Kistler force plate platform between 10 patients with unilateral vestibular impairments and 20 normal counterparts in the same sex ratio and age limits (50 ± 7). We evaluated excursion and velocity of center of pressure (COP) and path length in anteroposterior (AP) and mediolateral (ML) planes with eyes open and with eyes closed. Results. There was no significant difference between COP excursions in ML and AP planes between both groups with eyes open and eyes closed (p value > 0.05). In contrast, the difference between velocity and path length of COP in the mentioned planes was significant between both groups with eyes open and eyes closed (p value < 0.05). Conclusions. The present study showed the static instability and balance of patients with vestibular impairments indicated by the abnormal characteristics of body balance. PMID:27379198

  17. Development of a Method for Measuring Carbon Balance in Chemical Sequestration of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhongxian; Pan, Wei-Ping; Riley, John T.

    2006-09-09

    Anthropogenic CO2 released from fossil fuel combustion is a primary greenhouse gas which contributes to “global warming.” It is estimated that stationary power generation contributes over one-third of total CO2 emissions. Reducing CO2 in the atmosphere can be accomplished either by decreasing the rate at which CO2 is emitted into the atmosphere or by increasing the rate at which it is removed from it. Extensive research has been conducted on determining a fast and inexpensive method to sequester carbon dioxide. These methods can be classified into two categories, CO2 fixation by natural sink process for CO2, or direct CO2 sequestration by artificial processes. In direct sequestration, CO2 produced from sources such as coal-fired power plants, would be captured from the exhausted gases. CO2 from a combustion exhaust gas is absorbed with an aqueous ammonia solution through scrubbing. The captured CO2 is then used to synthesize ammonium bicarbonate (ABC or NH4HCO3), an economical source of nitrogen fertilizer. In this work, we studied the carbon distribution after fertilizer is synthesized from CO2. The synthesized fertilizer in laboratory is used as a “CO2 carrier” to “transport” CO2 from the atmosphere to crops. After biological assimilation and metabolism in crops treated with ABC, a considerable amount of the carbon source is absorbed by the plants with increased biomass production. The majority of the unused carbon source percolates into the soil as carbonates, such as calcium carbonate (CaCO3) and magnesium carbonate (MgCO3). These carbonates are environmentally benign. As insoluble salts, they are found in normal rocks and can be stored safely and permanently in soil. This investigation mainly focuses on the carbon distribution after the synthesized fertilizer is applied to soil. Quantitative examination of carbon distribution in an ecosystem is a challenging task since the carbon in the soil may come from various sources. Therefore synthesized 14C

  18. CSR BALANCED SCORECARD SYSTEMS AND BUSINESS PERFORMANCES: SMEs CASE STUDY

    Directory of Open Access Journals (Sweden)

    Edward Sek Khin Wong

    2016-01-01

    Full Text Available This paper aims to examine the performance measurement using the CSR Balanced Scorecard system in SMEs firms in Malaysia. It investigates the relationships of the four perspectives of CSR Balanced Scorecard system toward performance measurement. The purpose of this paper is to in- vestigate whether or not the improvement of the non-financial CSR measures will lead to the im- provement of performance measures. To test these relationships, data were collected using the four perspectives approach introduced by Utting (2007. The finding indicates that the organizational business performance can be greatly increased by putting greater emphasis to CSR measures. The results also reveal that the increases of firms customer’s satisfaction is caused by the increase imple- mentation of CSR measurement. At the end of the article, the implications of this study for SME industries and some suggestions are discussed for future studies.

  19. Understanding the future impacts of rapid ocean warming and acidification on the carbonate balance of coral reefs. ecosystems.

    Science.gov (United States)

    Hoegh-Guldberg, O.; Dove, S. G.

    2011-12-01

    Marine organisms and ecosystems are undergoing fundamental changes as a consequence of ocean warming and acidification, which must be understood if we are to anticipate and respond to the resulting changes to ecosystem services and functions. We have been investigating potential changes to the calcification and bioerosion rates of coral reefs using flow-through mesocosms at Heron Island on the southern Great Barrier Reef. In these experiments, we have been manipulating the temperature and pCO2 in order to simulate future ocean conditions described by IPCC scenarios (specifically B2, A1FI). We have also created pre-industrial conditions for comparison. Importantly, our system not only provides fine control over experimental conditions but also allows temperature and pCO2 to fluctuate with daily and seasonal changes measured (integrated over 3 h) at specific locations of interest on the Heron Island Reef, which allows a more 'realistic' analysis of the combined influences of ocean warming and acidification. In our first set of experiments, we have examined the impact of IPCC scenarios (year 2100) for a range of ecosystem phenomena relating to the carbonate balance of coral reefs including (1) phototrophic microborers within the dead skeletons of two coral species; (2) calcareous coralline algae, (3) turf algal communities in the presence and absence of grazing damselfish; (4) the calcification, growth, mortality and recruitment of the reef-building corals, and (5) microbial communities associated with corals. The overall conclusion of the studies conducted to date strongly suggests rapid movement to a negative carbonate balance for shallow water tropical coral reefs even under medium (B2) climate scenarios that involve SST increases of approximately +1.5oC and +250 ppm pCO2. Our conclusion is based on observations regarding key organisms that are involved in establishing the carbonate balance of coral reef organisms, and on the observed impacts of these conditions on

  20. The carbon balance of South America: status, decadal trends and main determinants

    Directory of Open Access Journals (Sweden)

    M. Gloor

    2012-01-01

    Full Text Available We attempt to summarize the carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric environment and climate. Flux estimation methods which we consider sufficiently reliable are fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and finally inventories of agricultural exports. Other routes to estimating land-atmosphere CO2 fluxes include atmospheric transport inverse modelling and vegetation model predictions but are hampered by the data paucity and the need for improved parameterisation. The available data we analyze suggest that South America was a net source to the atmosphere during the 1980s (∼0.3–0.4 Pg C yr−1 and close to neutral (∼0.1 Pg C yr−1 in the 1990s with carbon uptake in old-growth forests nearly compensating carbon losses due to fossil fuel burning and deforestation. Annual mean precipitation over tropical South America measured by Amazon River discharge has a long-term upward trend, although over the last decade, dry seasons have tended to be drier and longer (and thus wet seasons wetter, with the years 2005 and 2010 experiencing strong droughts. It is currently unclear what the effect of these climate changes on the old-growth forest carbon sink will be but first measurements suggest it may be weakened. Based on scaling of forest census data the net carbon balance of South America seems to have been an increased source roughly over the 2005–2010 period (a total of ∼1 Pg C of dead tree biomass released over several years due to forest drought response. Finally, economic development of the tropical forest regions of the continent is advancing steadily with exports of agricultural products being an important driver and witnessing a strong upturn over the

  1. Modelling Temporal Variability in the Carbon Balance of a Spruce/Moss Boreal Forest

    Science.gov (United States)

    Frolking, S.; Goulden, M. L.; Wofsy, S. C.; Fan, S.-M.; Sutton, D. J.; Munger, J. W.; Bazzaz, A. M.; Daube, B. C.; Crill, P. M.; Aber, J. D.; Band, L. E.; Wang, X.; Savages, K.; Moore, T.; Harriss, R. C.

    1996-01-01

    A model of the daily carbon balance of a black spruce/feathermoss boreal forest ecosystem was developed and results compared to preliminary data from the 1994 BOREAS field campaign in northern Manitoba, Canada. The model, driven by daily weather conditions, simulated daily soil climate status (temperature and moisture profiles), spruce photosynthesis and respiration, moss photosynthesis and respiration, and litter decomposition. Model agreement with preliminary field data was good for net ecosystem exchange (NEE), capturing both the asymmetrical seasonality and short-term variability. During the growing season simulated daily NEE ranged from -4 g C m(exp -2) d(exp -1) (carbon uptake by ecosystem) to + 2 g C m(exp -2) d(exp -1) (carbon flux to atmosphere), with fluctuations from day to day. In the early winter simulated NEE values were + 0.5 g C m(exp -2) d(exp -1), dropping to + 0.2 g C m(exp -2) d(exp -1) in mid-winter. Simulated soil respiration during the growing season (+ 1 to + 5 g C m(exp -2) d(exp -1)) was dominated by metabolic respiration of the live moss, with litter decomposition usually contributing less than 30% and live spruce root respiration less than 10% of the total. Both spruce and moss net primary productivity (NPP) rates were higher in early summer than late summer. Simulated annual NEE for 1994 was -51 g C m(exp -2) y(exp -1), with 83% going into tree growth and 17% into the soil carbon accumulation. Moss NPP (58 g C m(exp -2) d(exp -1)) was considered to be litter (i.e. soil carbon input; no net increase in live moss biomass). Ecosystem respiration during the snow-covered season (84 g Cm(exp -2)) was 58% of the growing season net carbon uptake. A simulation of the same site for 1968-1989 showed about 10-20% year-to-year variability in heterotrophic respiration (mean of + 113 g C m-2 y@1). Moss NPP ranged from 19 to 114 g C m(exp -2) y(exp -1); spruce NPP from 81 to 150 g C nt-2 y,@l; spruce growth (NPP minus litterfall) from 34 to 103 g C m

  2. Assessing the response of the Australian carbon balance to climate variability by assimilating satellite observations in a distributed ecosystem model

    Science.gov (United States)

    Exbrayat, Jean-François; Bloom, A. Anthony; Smallman, T. Luke; Williams, Mathew

    2016-04-01

    Terrestrial ecosystems offset about 25% of anthropogenic emissions of fossil fuel responsible for the current global warming. This long-term carbon sink exhibits a large inter-annual variability that recent studies have associated to the response of semi-arid ecosystems to variations in climate conditions and especially the occurrence of extreme events. For example, wet conditions during the 2010-2011 La Niña episode led to the strongest annual terrestrial carbon sink ever observed. Satellite observations of plant productivity and modelling experiments indicate that this anomalous sink was mostly located in the southern hemisphere where Australia experienced record-breaking rainfall. However, the durability of this extra-sink has yet to be assessed as dry conditions returned in northern Australia at the end of 2011, causing large-scale fires. In this paper we investigate the influence of climate variability on Australian ecosystems and we particularly focus on the resilience of the La Niña driven 2010-2011 sink to subsequent dry years. Therefore, we use the CARbon Data MOdel fraMework (CARDAMOM) data-assimilation system to retrieve the 21st century Australian terrestrial carbon cycle simulated by an ecosystem model in agreement with climate data and Earth Observations relevant to the biosphere: burned area, leaf area index and biomass. Accordingly with previous studies results indicate a strong influence of the El Niño/Southern Oscillation on the inter-annual variability of the Australian carbon balance at the continent-scale. More precisely, in 2010-2011 the La Niña-driven wet conditions led the continent to become a strong sink of atmospheric carbon. Then, dry conditions accompanied by intense fires returned at the end of 2011 and our analyses indicate that the totality of the northern Australian sink (north of 30°S) was re-emitted by late 2011 as fires immediately burnt the extra-fuel produced during the record wet seasons. These results raise concerns on

  3. Reconstruction of annual carbon dynamics and balance for an oligotrophic pine fen

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J.; Silvola, J.; Aaltonen, H. [Joensuu Univ. (Finland). Dept. of Biology; Talanov, A.; Ikkonen, E. [Karelian Research Centre of Russian Academy of Sciences (Russian Federation). Inst. of Biology; Nykaenen, H.; Martikainen, P.J. [National Public Health Inst. Kuopio (Finland). Dept. of Environmental Microbiology

    1996-12-31

    Atmospheric carbon dioxide (CO{sub 2}) is bound by mire vegetation in photosynthesis during the growing season, and is re-released by respiration of plants, soil animals and microorganisms consuming dead organic matter. A small proportion of annual primary production may fall below the water table to anoxic conditions and thus escapes the oxidative decomposition. Also from anoxic peat, carbon is released with clear seasonal and spatial variation as methane (CH{sub 4}.). The rate of carbon accumulation in peat depends on the annual inbalance of plant production and litter decomposition. Exchange of CO{sub 2} and CH{sub 4} between peat, vegetation and the atmosphere thus reflects the dynamics of carbon flows in the ecosystem. Net ecosystem CO{sub 2} exchange (PN), total CO{sub 2} release (RTOT) and CH{sub 4} release (D) from different treeless surfaces of low-sedge Sphagnum papillosum pine fen was studied in eastern Finland. (8 refs.)

  4. Soil respiration and carbon balance in a Moso bamboo (Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens) forest in subtropical China

    OpenAIRE

    Tang X.; Fan S; Qi L; Guan F; Cai C; Du M

    2015-01-01

    Understanding spatial and temporal variation in soil respiration (RS) in different forest ecosystems is crucial to estimate the global carbon balance. Bamboo forest is a special forest type in southern China covering an area of 5.38 million ha, 70% of which are Moso bamboo (Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens) forests. Bamboo forests contribute more than 10% to the whole carbon stock of forest ecosystems in China, and therefore play a critical role in the regional and nati...

  5. Current and future impacts of ultraviolet radiation on the terrestrial carbon balance

    Institute of Scientific and Technical Information of China (English)

    W. Kolby SMITH; Wei GAO; Heidi STELTZER

    2009-01-01

    One of the most documented effects of human activity on our environment is the reduction of stratospheric ozone resulting in an increase of biologically harmful ultraviolet (UV) radiation. In a less predictable manner, UV radiation incident at the surface of the earth is expected to be further modified in the future as a result of altered cloud condition, atmospheric aerosol concentration, and snow cover. Although UV radiation comprises only a small fraction of the total solar radiation that is incident at the earth's surface, it has the greatest energy per unit wavelength and, thus, the greatest potential to damage the biosphere. Recent investigations have highlighted numerous ways that UV radiation could potentially affect a variety of ecological processes, including nutrient cycling and the terrestrial carbon cycle. The objectives of the following literature review are to summarize and synthesize the available information relevant to the effects of UV radiation and other climate change factors on the terrestrial carbon balance in an effort to highlight current gaps in knowledge and future research directions for UV radiation research.

  6. Energy, water and carbon balance of managed forests: comparing the future to the past

    Science.gov (United States)

    Loustau, Denis; Moreaux, Virginie; Moisy, Christophe; Picart, Delphine; Lafont, Sébastien; Benest, Fabienne; Lagouarde, Jean-PIerre; Bosc, Alexandre

    2014-05-01

    Intensification of forest management concerns a growing fraction of temperate and tropical forests. It is thought to affect wider areas in the near future for facing biomass, fiber and wood demands. Intensively managed forests are submitted to increased soil preparation, fertilization, drainage, thinning, clear-cutting, whole tree - harvesting and rotation shortening. They are composed of fast growing stands commonly planted with enhanced tree varieties or clones of eucalypts, pines, poplars, willows among others. Altogether these practices have substantial effects on forest exchanges with atmosphere and groundwater and therefore on local and regional climates and water resources. Using data collected from flux tower sites, MODIS products and forest and soil inventories together with our process based model of forest growth, GO+, we analysed the impacts of intensified management on forest canopy exchanges of heat, short and longwave radiations, water and CO2 and its interaction with soil and climate. Results obtained under present climate conditions evidenced interactions between intensification effects and soil and climate conditions. We show that biophysical impacts on radiative forcing potential, through albedo increase and convective fluxes of heat and water, are in the same order of magnitude than changes in the biogeochemical cycle of carbon. Drought affects dramatically the net carbon and water balances of forest stands independent of management and age. However, the effects of successive management operations (ploughing, vegetation burial, thinning) overtook climate impacts and make the young stands and intensive alternatives more independent and resilient to climate change impacts. The model applications to the analysis of future climate scenarios allowed to attributing the role of management alternatives, soil conditions and climate and their interactions. For intensively managed forests, the frequency of soil preparation operations, the management

  7. CO{sub 2} and CH{sub 4} fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J.

    1997-12-31

    Release of CO{sub 2} from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO{sub 2} efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO{sub 2} and CH{sub 4} (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO{sub 2} under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH{sub 4} release was studied. The Holocene history of CO{sub 2} sequestration and CH{sub 4} emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO{sub 2} release from peat. A drought lasting from late May to July caused a 90 g C m{sup 2} net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO{sub 2} release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m{sup -2}a{sup -1} in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m{sup -2}a{sup -1} for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants

  8. Forest Management Shifts in the Western US and Potential Impacts on the Carbon Balance

    Science.gov (United States)

    Law, B. E.; Jones, M. O.; Yang, Z.; Berner, L. T.

    2015-12-01

    Forest harvest regimes are changing as land managers cope with fires, drought, and insect damage. Thinning on public lands, typically focused on removal of small trees that could act as fuel ladders, is increasing to reduce risk of crown fires and reduce competition for water in crowded stands. On private lands, drought and wildfires could lead to further shortening of harvest cycles (e.g. from 80 to 45 years) or thinning. To examine the effects of potential changes in management regimes vs climate on carbon processes in forests of Oregon, California and Washington, we used data from ancillary plots, inventories, and satellites to parameterize and test the CLM4.5 model. We first examined contemporary biomass loss over the western US to determine the baseline conditions prior to implementing harvest scenarios. Annual biomass mortality from fires and insects increased significantly (1996-2011), and mortality from insects was about twice that of fires. California, Oregon and Idaho were most impacted by fire-related biomass mortality, whereas Colorado, Montana and Washington were most impacted by insects. Harvest scenarios implemented in CLM4.5 include two thinning scenarios to reduce crown fire risk and drought stress, and a salvage scenario to remove trees remaining after recent beetle or fire related mortality; taking into account our previous work showing 70 - 85 % of salvaged biomass is removed and the remainder is left on-site. We simulated the effect of treatments on current and future net ecosystem carbon balance. Challenges of regional modeling of management effects on carbon and other important considerations are addressed.

  9. Seasonal and interannual variability of carbon dioxide and water balances of a grassland

    NARCIS (Netherlands)

    Jacobs, A.F.G.; Heusinkveld, B.G.; Holtslag, A.A.M.

    2007-01-01

    There is great international concern over the increase of atmospheric carbon dioxide and its effect on vegetation and climate, and vice versa. Many studies on this issue are based on climate model calculations or indirect satellite observations. In contrast we present a 12-year study (1994¿2005) on

  10. Source Apportionment of Elemental Carbon Across the San Francisco Bay Area Using Combined Radiocarbon and Chemical Mass Balances

    Science.gov (United States)

    Yoon, S.; Fairley, D.; Sheesley, R. J.

    2014-12-01

    The San Francisco Bay Area is impacted by ambient particulate matter (PM) from a variety of sources including motor vehicles, biomass burning, off-road vehicles, industry, and meat cooking. Ambient PM, especially fine PM (diameter less than 2.5μm, PM2.5), is known to negatively impact health. Elemental Carbon (EC) is one of the major constituents of PM2.5. It not only negatively affects health but is also a powerful short-lived climate forcer. The State of California and Bay Area Air Quality Management District (BAAQMD) have made efforts in regulating contribution of EC from diesel trucks and wood burning, respectively. These and other efforts have assisted in significantly reducing the annual average PM2.5 concentrations approximately 30% since 2005 and 70% since 1990. Despite these improvements, to better determine the relative contribution of contemporary vs. fossil carbon, radiocarbon source apportionment of EC was conducted on PM2.5 collected in the Bay Area. Measurements of the abundance of 14C in the EC fractions are used to quantify the relative contributions of fossil carbon (fossil fuel combustion, including motor vehicle exhaust) and contemporary carbon (biomass combustion and meat cooking). This comprehensive study included seven sites in the Bay Area and 12 months of sampling starting November 2011 through October 2012. The samples were composited to represent winter (November-February) and non-winter (March-October). In addition to radiocarbon analysis, Chemical Mass Balance (CMB) analysis using bulk PM2.5 composition and selected trace gases was used to understand the split among gasoline, natural gas, and diesel exhaust. Preliminary apportionment of the seven sites shows roughly equal contributions of fossil fuel and biomass burning/cooking for both winter and non-winter samples. There is evidence that the diesel contribution to EC, in particular, has decreased substantially over the last decade.

  11. Results of monitoring large carbon fiber post-tensioning systems in a balanced Cantilever Brdige (Dintelharbour Bridge, The Netherlands)

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Kaptijn, N.; Hageman, J.G.; Kuilboer, C.P.M.

    2012-01-01

    Steel post-tensioning systems and stay cables are susceptible to corrosion. Carbon fiber systems are not. However, there was no experience on the long term behavior of such post-tensioned elements. Four external tendons (75 m long), stressed to a load of 2650 kN, were applied in a large balanced can

  12. Land-use change to bioenergy production in Europe: implications for the greenhouse gas balance and soil carbon

    DEFF Research Database (Denmark)

    Don, Axel; Osborne, Bruce; Hastings, Astley;

    2012-01-01

    . These greenhouse gases (GHGs) need to be included into the carbon footprint calculation of different bioenergy crops under a range of soil conditions and management practices. This review compiles existing knowledge on agronomic and environmental constraints and GHG balances of the major European bioenergy crops...

  13. The greenhouse gas balance of the oil palm industry in colombia: a preliminary analysis. ii. greenhouse gas emissions and the carbon budget

    OpenAIRE

    Henson, Ian E.; Ruiz Romero, Rodrigo; Romero, Hernán Mauricio

    2013-01-01

    In the preceding paper we examined carbon sequestration in oil palm plantations and in mill products and by-products as part of a study of the greenhouse gas balance of palm oil production in Colombia, showing how this has changed over time. Here, we look at the opposing processes of greenhouse gas (GHG) emission and calculate the resulting net carbon budget for the industry. The main emission sources, in decreasing order of magnitude, assessed using ‘default’ or ‘most probable’ options, were...

  14. Carbon Balance of No-Till Soybean with Winter Wheat Cover Crop in the Southeastern United States

    Science.gov (United States)

    Gebremedhin, M. T.; Loescher, H.; Tsegaye, T.

    2012-12-01

    The southeast is an important agricultural region in the U.S. and key component of the continental carbon budget. Croplands in the region store a substantial amount of soil organic carbon (C). However, their C sink status may be altered under the projected changes in precipitation pattern for the region. The study was conducted at Winfred Thomas Agricultural Research Station, Hazel Green, Alabama (2007-2009). We investigated the seasonal and interannual variation in net ecosystem exchange of CO2 (NEE) of winter wheat (Tricticum aestivum) and soybean (Glycine max) using the eddy covariance method. Annual C balance ranged from the highest source in 2007 (NEE = 100 g C m-2 y-1) to sink (-20 g C m-2 y-1) in 2009. Annual ecosystem respiration (Re) ranged between 750 and 1013 g C m-2 y-1, while gross ecosystem productivity (GEP) was 650-1034 g C m-2 y-1. Seasonal NEE for soybean ranged between 42 and -66 g C m-2. Stronger winter wheat NEE (-80.0, -80.4, -40.0 g C m-2 for 2007, 2008 and 2009) than soybean suggested the importance of winter C uptakes offsetting summer C losses. Re was controlled by air temperature, and it varied between 286 and 542 g C m-2 for soybean, and between 160 and 313 g C m-2 for winter wheat. Precipitation was key determinant of C balance implying larger C release during drought periods. During fallow months, the site was C source. If we include removal of grain off site, this system could become a C source under all conditions.

  15. Extreme late-summer drought causes neutral annual carbon balance in southwestern ponderosa pine forests and grasslands

    International Nuclear Information System (INIS)

    We assessed the impacts of extreme late-summer drought on carbon balance in a semi-arid forest region in Arizona. To understand drought impacts over extremes of forest cover, we measured net ecosystem production (NEP), gross primary production (GPP), and total ecosystem respiration (TER) with eddy covariance over five years (2006–10) at an undisturbed ponderosa pine (Pinus ponderosa) forest and at a former forest converted to grassland by intense burning. Drought shifted annual NEP from a weak source of carbon to the atmosphere to a neutral carbon balance at the burned site and from a carbon sink to neutral at the undisturbed site. Carbon fluxes were particularly sensitive to drought in August. Drought shifted August NEP at the undisturbed site from sink to source because the reduction of GPP (70%) exceeded the reduction of TER (35%). At the burned site drought shifted August NEP from weak source to neutral because the reduction of TER (40%) exceeded the reduction of GPP (20%). These results show that the lack of forest recovery after burning and the exposure of undisturbed forests to late-summer drought reduce carbon sink strength and illustrate the high vulnerability of forest carbon sink strength in the southwest US to predicted increases in intense burning and precipitation variability. (letter)

  16. Work-Life Balance: A Study In The Petroleum Industry

    Directory of Open Access Journals (Sweden)

    Judy De Villiers

    2003-11-01

    Full Text Available A qualitative study was completed to discover how employees of a company in the petroleum industry define and experience the phenomenon of work-life balance, to identify the workplace determinants of work-life imbalance and to elicit some solutions for the problem. It was found that work-life balance is a personal issue that varies across time and situations and the underlying conflict experienced pertains to role overload and role interference. The most significant work-life conflict arises from complex workplace issues, including managing change, supervisory and technical competences, leadership, roles and accountabilities, and culture. Solutions to address the workplace issues, as well as the development of individual balance-enabling skills, are suggested. Opsomming’n Kwalitatiewe studie is onderneem om vas te stel hoe die werknemers van ’n maatskappy in die petroleumnywerheid die fenomeen van die werk-lewe ewewig definieer en ervaar, om die werkpleksdeterminante van ’n werk-lewe onewewigtigheid te identifiseer en om sekere oplossings vir die probleem aan die hand te doen. Dit is gevind dat werk-lewe ewewig ’n persoonlike saak is wat oor tyd en omstandighede varieer en die ervaarde onderliggende konflik na roloorladingsrolle en -inmenging verwys. Die mees betekenisvolle werk-lewe konflik tree na vore vanuit komplekse werkplekaangeleenthede, insluitende die bestuur van veranderings, toesighoudende en tegniese vaardighede, leierskap, rolle en aanspreeklikheid, asook kultuur. Oplossings om die werkpleksake aan te spreek, asook die ontwikkeling van individuele vaardighede om ’n ewewig teweeg te bring, word voorgestel.

  17. Qigong improves balance in young women:a pilot study

    Institute of Scientific and Technical Information of China (English)

    María Victoria González López-Arza; Enrique Varela-Donoso; Jesús Montanero-Fernández; Juan Rodríguez-Mansilla; Blanca González-Sánchez; Luis González López-Arza

    2013-01-01

    BACKGROUND:Balance problems are common in people of all ages and can lead to falls,thus causing fractures with consequent disability.Qigong practice has long been part of daily life in Chinese culture,and has good effects on physical health maintenance.OBJECTIVE:The present work describes the change in balance in young,healthy women after practising Qigong for eight weeks.DESIGN,SETTING,PARTICIPANTS AND INTERVENTIONS:The study took the form of a controlled,randomised longitudinal trial,and involved 30 women aged 18-25 years.The subjects had no prior experience of Qigong or Tai Chi and were unaware of the aims of the study.Subjects were randomly assigned to a Qigong intervention group or a control group.Those in the Qigong intervention group performed "exercises in 20 figures for health and long-life" (Wang Ziping) for 1 h twice per week,for 4 weeks.The control group undertook no exercise at all.MAIN OUTCOME MEASURES:The main outcome measure was the stabilometry values.These were obtained in a unipodal support test,using a plantar pressure platform with optical sensors.RESULTS:The Qigong subjects showed a significant improvement in their stabilometry results (40.1% pre-intervention and 56.4% post-intervention) (P<0.045),while no improvement was seen in the control group (51.2% pre-intervention and 53.5% post-intervention).At the beginning of the intervention,the stabilometry values recorded for the Qigong intervention group were worse than those recorded for the control group (40.15% and 51.21% respectively; P=0.121).However,a comparison of the post-intervention values between these groups showed that these differences have disappeared (P=0.653).CONCLUSION:Qigong can improve balance in healthy,young women.

  18. Effects of nutrient loading on the carbon balance of coastal wetland sediments

    Science.gov (United States)

    Morris, J.T.; Bradley, P.M.

    1999-01-01

    Results of a 12-yr study in an oligotrophic South Carolina salt marsh demonstrate that soil respiration increased by 795 g C m-2 yr-1 and that carbon inventories decreased in sediments fertilized with nitrogen and phosphorus. Fertilized plots became net sources of carbon to the atmosphere, and sediment respiration continues in these plots at an accelerated pace. After 12 yr of treatment, soil macroorganic matter in the top 5 cm of sediment was 475 g C m-2 lower in fertilized plots than in controls, which is equivalent to a constant loss rate of 40 g C m-2 yr-1. It is not known whether soil carbon in fertilized plots has reached a new equilibrium or continues to decline. The increase in soil respiration in the fertilized plots was far greater than the loss of sediment organic matter, which indicates that the increase in soil respiration was largely due to an increase in primary production. Sediment respiration in laboratory incubations also demonstrated positive effects of nutrients. Thus, the results indicate that increased nutrient loading of oligotrophic wetlands can lead to an increased rate of sediment carbon turnover and a net loss of carbon from sediments.

  19. The carbon balance and greenhouse effects of the Finnish forest sector at present, in the past and future

    Energy Technology Data Exchange (ETDEWEB)

    Pingoud, K. [Technical Research Centre of Finland, Espoo (Finland)

    1996-12-31

    In this study the greenhouse impact of the total Finnish forest sector was considered, which means that the estimated emissions and sink effects from exported forest products were also included. The forest biomass is and seems to be in the next decades the most important factor in the carbon balance of the total forest sector. The development alternatives of forest industries and waste management practices has still a remarkable influence on the greenhouse impact of the Finnish forest sector. The waste management practices in the future has an important influence on the emissions but the exact net greenhouse impact of the landfills is still uncertain. However, the methane emissions from existing landfills can be reduced essentially by gas recovery. Increased incineration and energy recovery of wood waste (and replacing fossil fuel use by it) is also a future alternative for reducing the greenhouse effects in the forest sector. The sequestration of carbon by increasing the storages of long-lived wood products in use meets difficulties in practice because of all the material losses in wood using chain and the natural removal of old wood products. An important advantage of mechanical wood processing and the succeeding refinement chain is still their relative low use of energy

  20. Biomethanation of vegetable market waste in an anaerobic baffled reactor: Effect of effluent recirculation and carbon mass balance analysis.

    Science.gov (United States)

    Gulhane, Madhuri; Khardenavis, Anshuman A; Karia, Sneha; Pandit, Prabhakar; Kanade, Gajanan S; Lokhande, Satish; Vaidya, Atul N; Purohit, Hemant J

    2016-09-01

    In the present study, feasibility of biomethanation of vegetable market waste in a 4-chambered anaerobic baffled reactor (ABR) was investigated at 30d hydraulic retention time and organic loading rate of 0.5gVS/L/d for one year. Indicators of process stability viz., butyrate/acetate and propionate/acetate ratios were consistent with phase separation in the different chambers, which remained unaltered even during recirculation of effluent. Chemical oxygen demand (COD) and volatile solids (VS) removal efficiencies were observed to be consistently high (above 90%). Corresponding biogas and methane yields of 0.7-0.8L/g VS added/d and 0.42-52L/g VS added/d respectively were among the highest reported in case of AD of vegetable waste in an ABR. Process efficiency of the ABR for vegetable waste methanation, which is indicated by carbon recovery factor showed that, nearly 96.7% of the input carbon considered for mass balance was accounted for in the product. PMID:27133362

  1. Roles of urban vegetation on balance of carbon and oxygen in Guangzhou, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The plant biomass and net primary production(NPP) of urban vegetation in Guangzhou were estimated by dimension analysis, treetruck volume, and harvest methods as well as relationship between biomass and NPP and so on.The biomass and NPP were respectively2875150t and 1058122 t/a.They were respectively 392495t and 64948 t/a in the built-up area and 2482655t and 993147 t/a in the unbuilt-uparea.It would make plant biomass, especially NPP decline obviously, if the unbuilt-up area were changed to the built-up area.The carboncontent of plant was 1328649 for the total and 13.78 t/hm2 for the mean, and amounts of carbon fixed and oxygen made by urban vegetationwere respectively 4.80 t/(hm2 @a) and 12.79 t/(hm2 @a) for the mean and 462624 t/a and 1232430 t/a for the total, which were equal to 1.45times and 1.04 times of those by human breathing.However, they were only equal to 7.61% and 4.97% of amount of carbon released andoxygen consumption in urban Guangzhou.The biomass and NPP of urban vegetation in Guangzhou only corresponded to 7.8% and 47.3% ofthose of southern subtropical evergreen broad-leaf forest in Dinghu Mountain.Therefore, the roles of Guangzhou urban vegetation in balance ofcarbon and oxygen would be increased greatly if it could be conserved and improved in some way.

  2. A mass balance approach to assess carbon dioxide evolution during erosional events

    International Nuclear Information System (INIS)

    The accelerated greenhouse effect and the degradation of land resources by water and wind erosion are two major, yet interrelated global environmental challenges. Accelerated decomposition of soil organic carbon (SOC) in cultivated soils results in decline in SOC stocks over time and also contributes to increased levels of CO2 in the atmosphere. Off-site transport of SOC in runoff waters during erosional events also contributes to SOC depletion, but there is a paucity of data in the literature documenting erosional SOC losses and the fate of eroded SOC. In this paper, we present a mass balance approach to compute CO2 evolved from mineralization of SOC during transport and deposition of eroded soils. Erosion-induced CO2 emission rates ranging between 6 and 52 g C m-2 yr-1 were computed using data on SOC stocks and dynamics from a series of long-term experiments conducted across a range of ecological regions. For the cropland of the world, we estimated an annual flux of 0.37 Pg CO2 -C to the atmosphere due to water erosion. This flux is significant and suggests that water erosion must be taken into consideration when constructing global and regional C budgets. Through its contribution to atmospheric CO2 increase, water erosion can have a positive feedback on the accelerated greenhouse effect. (author)

  3. Greenhouse gas balance of a subarctic tundra - importance of carbon dioxide, methane and nitrous oxide from different land cover types

    Science.gov (United States)

    Marushchak, M. E.; Biasi, C.; Elsakov, V.; Jokinen, S.; Lind, S. E.; Pitkämäki, A.; Virtanen, T.; Martikainen, P. J.

    2012-04-01

    The strong warming predicted for the Arctic has increased the need to understand how carbon (C) balance in tundra will respond to climate change. The large C reservoir of northern permafrost soils (50% of global belowground soil C pool; Tarnocai et al. 2009) may be threatened by warming and associated thawing of permafrost, which might lead to increased release of carbon dioxide (CO2) and methane (CH4) to the atmosphere. Moreover, the recent findings of high nitrous oxide (N2O) emissions from permafrost soils (Repo et al. 2009, Elberling et al. 2010) show that the large nitrogen pool in permafrost soils cannot be neglected anymore when predicting the atmospheric impact of Arctic tundra in a changing climate. Here we report the annual landscape scale (GHG) balance of subarctic tundra including all the three most important GHGs: CO2, CH4 and N2O. The study was conducted in Northeast European Russia in a heterogeneous landscape consisting of upland tundra, fens, willow wetlands and massive peat plateau complexes spotted by thermokarst lakes. Fluxes of CO2, CH4 and N2O were measured during two growing seasons and the cold season between using different chamber techniques at terrestrial ecosystems, and combination of gas gradient method and bubble collectors in thermokarst lakes. The plot scale results were up scaled to the landscape level using a land cover map based on a high-resolution QuickBird satellite image (Hugelius et al. 2011). The land cover types studied represent 97% of the whole area study area of 98.6 km2. On an annual basis the study area acted as a sink of C, but CH4 and N2O emissions caused it to be a net source of GHGs when considering the global warming potential (GWP; 100-year time horizon) of all three gases. Willow wetlands, fens and thermokarst lakes (16% of the landscape) were significant sources of CH4, while CH4 emissions from the rest of the landscape were negligible. Bare peat surfaces on peat plateaus, peat circles, acted as strong hotspots

  4. Climatic Benefit of Swiss Forest Cover Change: Including Albedo Change into Net Carbon Balance

    Science.gov (United States)

    Schwaab, J.; Lehning, M.; Bebi, P.

    2012-12-01

    Forests influence climate through physical, chemical and biological processes. It has been shown that warming caused by the comparatively low albedo of forests (albedo-effect), can reduce or even exceed cooling caused by carbon storage in forests (CO2-effect). Although warming caused by albedo and the amount of carbon storage depend on local characteristics, studies are lacking that investigate the combined local patterns of albedo and CO2-effect. Our study area, Switzerland, provides a variety of geographical features and thus the possibility to show how different geographical variables influence the two effects. We used the concept of radiative forcing to compare the effect of a changing albedo and a change in atmospheric CO2 concentration due to land cover change in the past. The change of forest cover was analysed over a period of 12 years based on aerial photographs. We estimate the albedo-effect by combining albedo data derived from the satellite sensor MODIS and data on snow cover derived from the satellite sensor AVHRR. Changes in carbon storage were calculated as differences in biomass and soil stocks of specific land cover classes. We found carbon storage induced cooling to be higher than albedo induced warming everywhere in Switzerland. However, especially in altitudes over 1200 m the albedo-effect reduced the benefits of carbon storage by more than 50%. In lower altitudes the albedo change was less important. The albedo-effect in altitudes above 1200 m was more relevant because of a more persistent snow-cover, a slightly higher global radiation and less additional carbon storage. The relevance of warming caused by an albedo change did not only depend on altitude, but also on the characteristics of forest cover change. While transitions from open land to open forest were accompanied by high albedo changes, the albedo change was only marginal if open forest turned into closed forest. Since snow cover has a large influence on the albedo effect, we included

  5. Integrating Remote Sensing, Field Observations, and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U.S.

    Energy Technology Data Exchange (ETDEWEB)

    B.E. Law; D. Turner; M. Goeckede

    2010-06-01

    GOAL: To develop and apply an approach to quantify and understand the regional carbon balance of the west coast states for the North American Carbon Program. OBJECTIVE: As an element of NACP research, the proposed investigation is a two pronged approach that derives and evaluates a regional carbon (C) budget for Oregon, Washington, and California. Objectives are (1) Use multiple data sources, including AmeriFlux data, inventories, and multispectral remote sensing data to investigate trends in carbon storage and exchanges of CO2 and water with variation in climate and disturbance history; (2) Develop and apply regional modeling that relies on these multiple data sources to reduce uncertainty in spatial estimates of carbon storage and NEP, and relative contributions of terrestrial ecosystems and anthropogenic emissions to atmospheric CO2 in the region; (3) Model terrestrial carbon processes across the region, using the Biome-BGC terrestrial ecosystem model, and an atmospheric inverse modeling approach to estimate variation in rate and timing of terrestrial uptake and feedbacks to the atmosphere in response to climate and disturbance. APPROACH: In performing the regional analysis, the research plan for the bottom-up approach uses a nested hierarchy of observations that include AmeriFlux data (i.e., net ecosystem exchange (NEE) from eddy covariance and associated biometric data), intermediate intensity inventories from an extended plot array partially developed from the PI's previous research, Forest Service FIA and CVS inventory data, time since disturbance, disturbance type, and cover type from Landsat developed in this study, and productivity estimates from MODIS algorithms. The BIOME-BGC model is used to integrate information from these sources and quantify C balance across the region. The inverse modeling approach assimilates flux data from AmeriFlux sites, high precision CO2 concentration data from AmeriFlux towers and four new calibrated CO2 sites

  6. Comparative water balance study of forest and fallow plots

    Directory of Open Access Journals (Sweden)

    Móricz N

    2012-08-01

    Full Text Available Increasing pressure on groundwater due to land use change (e.g., afforestation and future climate change will alter the recharge of groundwater aquifers, causing shifts in water table levels and hence influencing the avai­lable groundwater resources. The effect of land use change on groundwater resources has initiated a major scientific debate during the last decades between foresters and experts in water management in Hungary and in several other countries. The aim of this study was to compare water balances of two different vegetation covers, a groundwater dependent oak forest and a nearby fallow area in the Hungarian Lowland. Water balance components for an oak and a fallow plots, exposed to similar weather conditions and with similar soils, were estimated and compared by calibrating the Hydrus 1-D model using mea­sured soil water content and groundwater levels. The difference in the groundwater consumption was analyzed in details during dry and wet growing seasons. Transpiration at the fallow plot was only about two-thirds of that in the oak forest, while groundwater consumption was three times higher in the forest than at the fallow plot throughout the two-year study. During the dry growing season, the proportion of groundwater use from the total transpiration reached up to 90% at the oak plot. According to the model, in the dry growing season in 2007 both vegetation covers relied significantly on groundwater resources, while in 2008 the consumption of groundwater was notably reduced due to the wet weather at both plots.

  7. Effect of forest drainage on the carbon balance and greenhouse impact of Finnish peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Laine, J.; Minkkinen, K.; Laiho, R. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    The aim of this project is to produce an estimate of the change in the biomass and peat carbon stores arising from the drainage of peatlands for forestry, and of the change of greenhouse impact of these ecosystems. The study shows that the subsidence of mire surfaces due to drainage has been relatively small, on average about 20 cm. The observed increase in bulk density after drainage is caused by the physical compression of peat and the post-drainage input of organic material in the form of litter production from the above and below ground parts of the tree layer. Oxidative decay of organic matter may have further increased the compaction of peat, especially in fertile sites. When the changes in peat and vegetation carbon stores are summed up, it seems that, within the site types studied, the total impact of drainage to the ecosystem carbon store is close to zero on the nutrient rich sites and clearly positive on the poorer types. Water level drawdown in peatlands after drainage for forestry appears to decrease the greenhouse impact at least for a few hundred years. The estimated changes in all three emission components (CH{sub 4} emissions, CO{sub 2} sink from peatland and CO{sub 2} sequestered in trees) reduce the radiative forcing by approximately similar amounts

  8. Towards operational remote sensing of forest carbon balance across Northern Europe

    Directory of Open Access Journals (Sweden)

    P. Olofsson

    2008-05-01

    Full Text Available Monthly averages of ecosystem respiration (ER, gross primary production (GPP and net ecosystem exchange (NEE over Scandinavian forest sites were estimated using regression models driven by air temperature (AT, absorbed photosynthetically active radiation (APAR and vegetation indices. The models were constructed and evaluated using satellite data from Terra/MODIS and measured data collected at seven flux tower sites in northern Europe. Data used for model construction was excluded from the evaluation. Relationships between ground measured variables and the independent variables were investigated.

    It was found that the enhanced vegetation index (EVI at 250 m resolution was highly noisy for the coniferous sites, and hence, 1 km EVI was used for the analysis. Linear relationships between EVI and the biophysical variables were found: correlation coefficients between EVI and GPP, NEE, and AT ranged from 0.90 to 0.79 for the deciduous data, and from 0.85 to 0.67 for the coniferous data. Due to saturation, there were no linear relationships between normalized difference vegetation index (NDVI and the ground measured parameters found at any site. APAR correlated better with the parameters in question than the vegetation indices. Modeled GPP and ER were in good agreement with measured values, with more than 90% of the variation in measured GPP and ER being explained by the coniferous models. The site-specific respiration rate at 10°C (R10 was needed for describing the ER variation between sites. Even though monthly NEE was modeled with less accuracy than GPP, 61% and 75% (dec. and con., respectively of the variation in the measured time series was explained by the model. These results are important for moving towards operational remote sensing of forest carbon balance across Northern Europe.

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

    Science.gov (United States)

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

    2016-07-25

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

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

    Science.gov (United States)

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

    2016-07-25

    For maintenance of cellular homeostasis, the actions of growth-promoting hormones must be attenuated when nutrient and energy become limiting. The molecular mechanisms that coordinate hormone-dependent growth responses with nutrient availability remain poorly understood in plants [1, 2]. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator that integrates nutrient and energy signaling to regulate growth and homeostasis in both animals and plants [3-7]. Here, we show that sugar signaling through TOR controls the accumulation of the brassinosteroid (BR)-signaling transcription factor BZR1, which is essential for growth promotion by multiple hormonal and environmental signals [8-11]. Starvation, caused by shifting of light-grown Arabidopsis seedlings into darkness, as well as inhibition of TOR by inducible RNAi, led to plant growth arrest and reduced expression of BR-responsive genes. The growth arrest caused by TOR inactivation was partially recovered by BR treatment and the gain-of-function mutation bzr1-1D, which causes accumulation of active forms of BZR1 [12]. Exogenous sugar promoted BZR1 accumulation and seedling growth, but such sugar effects were largely abolished by inactivation of TOR, whereas the effect of TOR inactivation on BZR1 degradation is abolished by inhibition of autophagy and by the bzr1-1D mutation. These results indicate that cellular starvation leads sequentially to TOR inactivation, autophagy, and BZR1 degradation. Such regulation of BZR1 accumulation by glucose-TOR signaling allows carbon availability to control the growth promotion hormonal programs, ensuring supply-demand balance in plant growth. PMID:27345161

  11. Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: a study with a regional climate model

    OpenAIRE

    Angelen, J. H.; Lenaerts, J. T. M.; S. Lhermitte; X. Fettweis; P. Kuipers Munneke; M. R. van den Broeke; van Meijgaard, E.

    2012-01-01

    We present a sensitivity study of the surface mass balance (SMB) of the Greenland Ice Sheet, as modeled using a regional atmospheric climate model, to various parameter settings in the albedo scheme. The snow albedo scheme uses grain size as a prognostic variable and further depends on cloud cover, solar zenith angle and black carbon concentration. For the control experiment the overestimation of absorbed shortwave radiation (+6%) at the K-transect (west Greenland) for the period 2004–2009 is...

  12. COMPARATIVE STUDY ON THE EFFECT OF SQUARE STEPPING EXERCISES VERSUS BALANCE TRAINING EXERCISES ON FEAR OF FALL AND BALANCE IN ELDERLY POPULATION

    OpenAIRE

    Harshika Bhanusali; Vishnu Vardhan; Tushar Palekar; Shilpa Khandare

    2016-01-01

    Background: Balance is a complex process involving the reception and integration of sensory inputs and the planning and execution of movement to achieve a goal requiring upright posture. The need of the study is to compare the effect of square stepping exercises versus balance exercises on fear of falling and balance in elderly. Aims and Objectives: 1. To study the effects of square stepping exercise on older adults to improve balance impairments and reducing fear of falling. 2. To identi...

  13. The Study On Load Balancing Strategies In Distributed Computing System

    Directory of Open Access Journals (Sweden)

    Md. Firoj Ali

    2012-05-01

    Full Text Available A number of load balancing algorithms were developed in order to improve the execution of a distributed application in any kind of distributed architecture. Load balancing involves assigning tasks to each processor and minimizing the execution time of the program. In practice, it would be possible even to execute the applications on any machine of worldwide distributed systems. However, the ‘distributed system’ becomes popular and attractive with the introduction of the web. This results in a significant performance improvement for the users. This paper describes the necessary, newly developed, principal concepts for several load balancing techniques in a distributed computing environment. This paper also includes various types of load balancing strategies, their merits, demerits and comparison depending on certain parameters.

  14. Noise Study of a Heat Balanced Sigma-Delta Bolometer

    OpenAIRE

    Denoual, Matthieu; Brouard, D.; Veith, A; Pouliquen, Mathieu; Attia, Patrick; Allègre, Gilles

    2013-01-01

    The paper presents the modeling of a heat balanced sigma-delta bolometer with Matlab Simulink®. In particular, the noise sources are modeled to enable the evaluation of the output measurement resolution.

  15. Biotic Processes Regulating the Carbon Balance of Desert Ecosystems - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Robert S [UNR; Smith, Stanley D [UNLV; Evans, Dave [WSU; Ogle, Kiona [ASU; Fenstermaker, Lynn [DRI

    2012-12-13

    Our results from the 10-year elevated atmospheric CO{sub 2} concentration study at the Nevada Desert FACE (Free-air CO{sub 2} Enrichment) Facility (NDFF) indicate that the Mojave Desert is a dynamic ecosystem with the capacity to respond quickly to environmental changes. The Mojave Desert ecosystem is accumulating carbon (C), and over the 10-year experiment, C accumulation was significantly greater under elevated [CO{sub 2}] than under ambient, despite great fluctuations in C inputs from year to year and even apparent reversals in which [CO{sub 2}] treatment had greater C accumulations.

  16. Water Balance Study of a Groundwater-dependent Oak Forest

    Directory of Open Access Journals (Sweden)

    MÓRICZ, Norbert

    2010-01-01

    Full Text Available The objectives of this study were (1 to estimate the water balance components of an oak standby calibrating a Hydrus 1-D model, (2 to determine the groundwater consumption by the water tablefluctuation method and (3 to compare the results of the modelling with a remote-sensing based estimation.Model simulation described the observed soil moisture and groundwater level relatively well, theroot mean square errors varied between 12.0 and 14.9% for the soil moisture measurements and 5.0%for the groundwater level. Groundwater consumption was estimated also by the water table fluctuationmethod, which provided slightly different groundwater consumption rates than estimated by theHydrus model simulation. The simulated evapotranspiration was compared with results of a remotesensingbased estimation using the surface temperature database of MODIS.According to the Hydrus model, the estimated evapotranspiration resulted from transpiration(73%, interception loss (23% and soil surface evaporation (4% in the two-year study period. Theproportion of groundwater consumption was 58% of the total transpiration. During the dry growingseason of 2007 the groundwater consumption was significant with 66% of the total transpiration.Water supply from groundwater was found to be less important in the wet growing season of 2008with 50%. The remote-sensing based estimation of evapotranspiration was about 4% lower than themodel based results of nearby comparable sites.

  17. Culture Management through the balanced scorecard : a case study

    OpenAIRE

    Woodley, P M

    2007-01-01

    Neuro Linguistic Programming argues that repeating previous behaviour will only succeed in delivering previous outcomes. Kaplan and Norton’s Balanced Scorecard is about getting different results. For successful change, managing complex and higher functions such as managing motivation and the beliefs of staff members must take their place alongside environmental and capability issues such as physical equipments. Mechanistic processes such as the Balanced Scorecard can neverthele...

  18. CSR BALANCED SCORECARD SYSTEMS AND BUSINESS PERFORMANCES: SMEs CASE STUDY

    OpenAIRE

    Edward Sek Khin Wong; Rusnah Muhamad; Lau Wee Yeap

    2016-01-01

    This paper aims to examine the performance measurement using the CSR Balanced Scorecard system in SMEs firms in Malaysia. It investigates the relationships of the four perspectives of CSR Balanced Scorecard system toward performance measurement. The purpose of this paper is to in- vestigate whether or not the improvement of the non-financial CSR measures will lead to the im- provement of performance measures. To test these relationships, data were collected using the four perspectives approac...

  19. Simulation-Based Approach for Studying the Balancing of Local Smart Grids with Electric Vehicle Batteries

    Directory of Open Access Journals (Sweden)

    Juhani Latvakoski

    2015-07-01

    Full Text Available Modern society is facing great challenges due to pollution and increased carbon dioxide (CO2 emissions. As part of solving these challenges, the use of renewable energy sources and electric vehicles (EVs is rapidly increasing. However, increased dynamics have triggered problems in balancing energy supply and consumption demand in the power systems. The resulting uncertainty and unpredictability of energy production, consumption, and management of peak loads has caused an increase in costs for energy market actors. Therefore, the means for studying the balancing of local smart grids with EVs is a starting point for this paper. The main contribution is a simulation-based approach which was developed to enable the study of the balancing of local distribution grids with EV batteries in a cost-efficient manner. The simulation-based approach is applied to enable the execution of a distributed system with the simulation of a local distribution grid, including a number of charging stations and EVs. A simulation system has been constructed to support the simulation-based approach. The evaluation has been carried out by executing the scenario related to balancing local distribution grids with EV batteries in a step-by-step manner. The evaluation results indicate that the simulation-based approach is able to facilitate the evaluation of smart grid– and EV-related communication protocols, control algorithms for charging, and functionalities of local distribution grids as part of a complex, critical cyber-physical system. In addition, the simulation system is able to incorporate advanced methods for monitoring, controlling, tracking, and modeling behavior. The simulation model of the local distribution grid can be executed with the smart control of charging and discharging powers of the EVs according to the load situation in the local distribution grid. The resulting simulation system can be applied to the study of balancing local smart grids with EV

  20. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-01-01

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning. PMID:25766381

  1. Effect of initial glucose concentrations on carbon material and energy balances in hydrogen-producing Clostridium tyrobutyricum JM1.

    Science.gov (United States)

    Jo, Ji Hye; Lee, Dae Sung; Kim, Junhoon; Park, Jong Moon

    2009-03-01

    The carbon metabolism of newly isolated Clostridium tyrobutyricum JM1 was investigated at varying initial glucose concentrations (27.8-333.6mM). Because an understanding of metabolic regulations was required to provide guidance for further effective metabolic design or optimization, in this case, maximizing hydrogen production, carbon material, and energy balances by C. tyrobutyricum JM1 were determined and applied in anaerobic glucose metabolism. The overall carbon distribution suggested that initial glucose concentrations had strong influence on the stoichiometric coefficients of products and the molar production of ATP on the formation of biomass. C. tyrobutyricum JM1 had a high capacity for hydrogen production at the initial glucose concentration of 222.4 mM with high concentrations of acetate and butyrate.

  2. A new electrodynamic balance design for low temperature studies

    Directory of Open Access Journals (Sweden)

    H.-J. Tong

    2014-07-01

    Full Text Available In this paper we describe a newly designed cold electrodynamic balance (CEDB system, which was built to study the evaporation kinetics and freezing properties of supercooled water droplets. The temperature of the CEDB chamber at the location of the levitated water droplet can be controlled in the range: −40 to +40 °C, which is achieved using a combination of liquid nitrogen cooling and heating by positive temperature coefficient heaters. The measurement of liquid droplet radius is obtained by analyzing the Mie elastic light scattering from a 532 nm laser. The Mie scattering signal was also used to characterize and distinguish droplet freezing events; liquid droplets produce a regular fringe pattern whilst the pattern from frozen particles is irregular. The evaporation rate of singly levitated water droplets was calculated from time resolved measurements of the radii of evaporating droplets and a clear trend of the evaporation rate on temperature was measured. The statistical freezing probabilities of aqueous pollen extracts (pollen washing water are obtained in the temperature range: −4.5 to −40 °C. It was found that that pollen washing water from water birch (Betula fontinalis occidentalis pollen can act as ice nuclei in the immersion freezing mode at temperatures as warm as −22.45 (±0.65 °C.

  3. Carbon Footprint Analysis for a GRAPE Production Case Study

    Science.gov (United States)

    Sirca, C.; Marras, S.; Masia, S.; Duce, P.; Zara, P.; Spano, D.

    2013-12-01

    Agriculture activities can play a double role in emitting or sequestering carbon from the atmosphere. Mitigation of greenhouse gas (GHG) emissions in agriculture is one of the most urgent research subjects in the framework of enhancing environmental stewardship. However, little is known about the role of the agriculture in the global carbon balance, since most of the studies applied the Eddy Covariance technique in natural or semi-natural ecosystems to investigate their role in mitigate the anthropogenic carbon release. The application of the Eddy Covariance technique in agricultural systems could greatly improve our knowledge about their role on the global carbon budget and help in modeling the related processes. In addition, there is a growing request from producers, trade companies, and customers on the assessment of the environmental impact of a production process related to agricultural high quality products. In recent years, particular attention was put on the estimation of GHG emissions deriving from productive processes. In this context, a useful tool is the Life Cycle Assessment (LCA), which represents a methodology to estimate GHG emissions related to the entire life cycle of a product. The Carbon Footprint (CF) analysis represents a subset of the LCA, which only considers CO2 emissions with an impact on climate change. With respect to the wine industry, most of studies focused on the CF analysis related to the wine making process in the cellar, while a few studies analyzed the GHG emissions related to the grape production. The aim of this work was to quantify the CO2 emissions due to the grape production and emphasize the double role of a vineyard as a carbon sink or source. An Eddy Covariance station was set up in a representative vineyard located in the Mediterranean Basin (Sardinia, Italy) to measure the net carbon exchange between the surface and the atmosphere. The CF analysis was also conducted to compute the carbon balance of the grape production

  4. Study of a double bubbler for material balance in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Hugues Lambert

    2013-09-01

    The objective of this project was to determine the potential of a double bubbler to measure density and fluid level of the molten salt contained in an electrorefiner. Such in-situ real-time measurements can provide key information for material balances in the pyroprocessing of the nuclear spent fuel. This theoretical study showed this technique has a lot of promise. Four different experiments were designed and performed. The first three experiments studied the influence of a variety of factors such as depth difference between the two tubes, gas flow rate, the radius of the tubes and determining the best operating conditions. The last experiment purpose was to determine the precision and accuracy of the apparatus during specific conditions. The elected operating conditions for the characterization of the system were a difference of depth of 25 cm and a flow rate of 55 ml/min in each tube. The measured densities were between 1,000 g/l and 1,400g/l and the level between 34cm and 40 cm. The depth difference between the tubes is critical, the larger, the better. The experiments showed that the flow rate should be the same in each tube. The concordances with theoretical predictions were very good. The density precision was very satisfying (spread<0.1%) and the accuracy was about 1%. For the level determination, the precision was also very satisfying (spread<0.1%), but the accuracy was about 3%. However, those two biases could be corrected with calibration curves. In addition to the aqueous systems studied in the present work, future work will focus on examining the behavior of the double bubbler instrumentation in molten salt systems. The two main challenges which were identified in this work are the effect of the temperature and the variation of the superficial tension.

  5. COMPREHENSIVE STUDY ON LOAD BALANCING TECHNIQUES IN CLOUD

    Directory of Open Access Journals (Sweden)

    B S Rajeshwari

    2014-06-01

    Full Text Available Due to advancement in technology and growth in human society, it is necessary to work in an environment that reduces cost, utilizes resources effectively, reduces man power and minimizes space utilization. This led to the development of Cloud Computing technology. Cloud computing is a kind of distributed computing with a collection of computing resources located in distributed data centers. It provides massively scalable IT related capabilities to multiple external customers on “pay per use” concept using internet technologies. The increase in the web traffic and different services day by day makes load balancing a critical research topic. Load balancing is one of the central issues in cloud computing. It is the process of distributing the load optimally and evenly among various servers. Proper load balancing in cloud improves the performance factors such as resource utilization, job response time, scalability, throughput, system stability and energy consumption. Many researchers have proposed various load balancing techniques. This paper presents description of various existing centralized and distributed load balancing techniques in cloud environment.

  6. COMPREHENSIVE STUDY ON LOAD BALANCING TECHNIQUES IN CLOUD

    Directory of Open Access Journals (Sweden)

    B S Rajeshwari

    2015-11-01

    Full Text Available Due to advancement in technology and growth in human society, it is necessary to work in an environment that reduces cost, utilizes resources effectively, reduces man power and minimizes space utilization. This led to the development of Cloud Computing technology. Cloud computing is a kind of distributed computing with a collection of computing resources located in distributed data centers. It provides massively scalable IT related capabilities to multiple external customers on "pay per use" concept using internet technologies. The increase in the web traffic and different services day by day makes load balancing a critical research topic. Load balancing is one of the central issues in cloud computing. It is the process of distributing the load optimally and evenly among various servers. Proper load balancing in cloud improves the performance factors such as resource utilization, job response time, scalability, throughput, system stability and energy consumption. Many researchers have proposed various load balancing techniques. This paper presents description of various existing centralized and distributed load balancing techniques in cloud environment.

  7. Subterranean ventilation: a key but poorly known process affecting the carbon balance of semi-arid ecosystems

    Science.gov (United States)

    López Ballesteros, Ana; Sánchez Cañete, Enrique P.; Serrano Ortiz, Penélope; Kowalski, Andrew S.; Oyonarte, Cecilio; Domingo, Francisco

    2016-04-01

    Subterranean ventilation, conceived as the advective transport of CO2-rich air from the vadose zone to the atmosphere through a porous media (i.e. soil or snow; Sánchez-Cañete et al., 2013), has arisen as an important process contributing to the carbon (C) balance of Mediterranean ecosystems (Kowalski et al., 2008; Sánchez-Cañete et al., 2011; Serrano-Ortiz et al., 2014), apart from other well-known biotic processes (i.e. plant photosynthesis, autotrophic and heterotrophic respiration). Recent studies have linked this subterranean CO2 release to fluctuations in the friction velocity or wind speed under drought conditions when water-free soil pores enable air transport (Rey et al., 2012a, 2013), however, barometric pressure variations has been suggested as another important driver (Sánchez-Cañete et al., 2013). In this study, we investigate this process in newly studied semi-arid grassland located in SE Spain, as the ideal ecosystem to do so given the great length of the dry season and the slight biotic activity limited to the winter season. Preliminary results, based on unpublished analyzed eddy covariance data and subterranean CO2 molar fraction measurements, confirm the presence of ventilation events from May to October for seven years 2009-2015. During these events, increases in the friction velocity correlates with sizeable CO2 emissions of up to ca.10 μmol m‑2 s‑1, and CO2 molar fraction regularly drops 2000-3000 ppm just after the turbulence peak, at several depths below the soil surface (0.15 and 1.5 m). Additionally, during the driest period (July-August), the friction velocity explains from 37% to 57% of the net C emission variability. On the other hand, the model residuals do not show a significant relationship, neither with air pressure nor with soil water content. Overall, the results found in this newly monitored site demonstrate, as shown by past research, the relevance of subterranean ventilation as a key process in the C balance of

  8. A review of carbon and nitrogen balances in switchgrass grown for energy

    International Nuclear Information System (INIS)

    Increased atmospheric CO2 caused partly by burning fossil fuels, is assumed to elevate the risk of global warming, while nitrate contamination of surface runoff and groundwater from fertilizer and agricultural wastes constitutes a serious environmental hazard on a regional scale. Switchgrass (Panicum virgatum L.) grown as an energy crop could reduce atmospheric CO2 accumulation by replacing fossil fuels and sequestering C. It could also improve soil productivity by C sequestration, and reduce NO3-1 contamination of water by absorbing N lost from fertilizer and agricultural waste if planted in filter strips on adjacent land. The objective of this study was to assess potential impacts of switchgrass on C and N balances by reviewing and synthesizing information from current literature, unpublished data and on-going research. Replacing fossil fuels with switchgrass, or any other biomass, will have a much greater effect on atmospheric CO2 than C sequestration. This is because replacing fossil fuels provides a cumulative effect, while C sequestration offers only a one-time benefit. Furthermore, switchgrass will provide net gains in C sequestration only if it replaces annual row crops, but not if it replaces grazed pasture. Nitrogen recovery by switchgrass in an Alabama study was 65.6%, which compares favorably with the 50% recovery frequently quoted as the norm for wheat (Triticum aestivum L.) and corn (Zea mays L.). (Author)

  9. Seasonal course of CO{sub 2} exchange and carbon balance in fruits of Cinnamomum camphora

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K. [Nagoya Univ. (Japan). Faculty of Agriculture; Takano, Y. [Dept. of Forestry, Fukuoka Pref., Fukuoka (Japan)

    1997-09-01

    CO{sub 2} exchange in fruits of Cinnamomum camphora was studied over a growing season. Dark respiration was exponentially related to temperature. Light dependence on CO{sub 2} photosynthetic refixation was approximated by the hyperbolic function. Seasonal variation in maximum CO{sub 2} refixation capacity ranged between 52 and 174 per cent, with maximum capacity in early August. Daily photosynthetic CO{sub 2} refixation ranged between 17 and 51 per cent over the growth period. Seasonal variation translocation rate to the fruit was determined, and the results used to develop a simple carbon flow model of fruit development. The relationship between dry weight increment in the fruit and translocation rate was also derived. It was found to be approximated by a linear function. 16 refs., 7 figs.

  10. Carbon Dioxide Reduction Technology Trade Study

    Science.gov (United States)

    Jeng, Frank F.; Anderson, Molly S.; Abney, Morgan B.

    2011-01-01

    For long-term human missions, a closed-loop atmosphere revitalization system (ARS) is essential to minimize consumables. A carbon dioxide (CO2) reduction technology is used to reclaim oxygen (O2) from metabolic CO2 and is vital to reduce the delivery mass of metabolic O2. A key step in closing the loop for ARS will include a proper CO2 reduction subsystem that is reliable and with low equivalent system mass (ESM). Sabatier and Bosch CO2 reduction are two traditional CO2 reduction subsystems (CRS). Although a Sabatier CRS has been delivered to International Space Station (ISS) and is an important step toward closing the ISS ARS loop, it recovers only 50% of the available O2 in CO2. A Bosch CRS is able to reclaim all O2 in CO2. However, due to continuous carbon deposition on the catalyst surface, the penalties of replacing spent catalysts and reactors and crew time in a Bosch CRS are significant. Recently, technologies have been developed for recovering hydrogen (H2) from Sabatier-product methane (CH4). These include methane pyrolysis using a microwave plasma, catalytic thermal pyrolysis of CH4 and thermal pyrolysis of CH4. Further, development in Sabatier reactor designs based on microchannel and microlith technology could open up opportunities in reducing system mass and enhancing system control. Improvements in Bosch CRS conversion have also been reported. In addition, co-electrolysis of steam and CO2 is a new technology that integrates oxygen generation and CO2 reduction functions in a single system. A co-electrolysis unit followed by either a Sabatier or a carbon formation reactor based on Bosch chemistry could improve the overall competitiveness of an integrated O2 generation and CO2 reduction subsystem. This study evaluates all these CO2 reduction technologies, conducts water mass balances for required external supply of water for 1-, 5- and 10-yr missions, evaluates mass, volume, power, cooling and resupply requirements of various technologies. A system

  11. Severe dry winter affects plant phenology and carbon balance of a cork oak woodland understorey

    Science.gov (United States)

    Correia, A. C.; Costa-e-Silva, F.; Dubbert, M.; Piayda, A.; Pereira, J. S.

    2016-10-01

    Mediterranean climates are prone to a great variation in yearly precipitation. The effects on ecosystem will depend on the severity and timing of droughts. In this study we questioned how an extreme dry winter affects the carbon flux in the understorey of a cork oak woodland? What is the seasonal contribution of understorey vegetation to ecosystem productivity? We used closed-system portable chambers to measure CO2 exchange of the dominant shrub species (Cistus salviifolius, Cistus crispus and Ulex airensis), of the herbaceous layer and on bare soil in a cork oak woodland in central Portugal during the dry winter year of 2012. Shoot growth, leaf shedding, flower and fruit setting, above and belowground plant biomass were measured as well as seasonal leaf water potential. Eddy-covariance and micrometeorological data together with CO2 exchange measurements were used to access the understorey species contribution to ecosystem gross primary productivity (GPP). The herbaceous layer productivity was severely affected by the dry winter, with half of the yearly maximum aboveground biomass in comparison with the 6 years site average. The semi-deciduous and evergreen shrubs showed desynchronized phenophases and lagged carbon uptake maxima. Whereas shallow-root shrubs exhibited opportunistic characteristics in exploiting the understorey light and water resources, deep rooted shrubs showed better water status but considerably lower assimilation rates. The contribution of understorey vegetation to ecosystem GPP was lower during summer with 14% and maximum during late spring, concomitantly with the lowest tree productivity due to tree canopy renewal. The herbaceous vegetation contribution to ecosystem GPP never exceeded 6% during this dry year stressing its sensitivity to winter and spring precipitation. Although shrubs are more resilient to precipitation variability when compared with the herbaceous vegetation, the contribution of the understorey vegetation to ecosystem GPP can

  12. The carbon balance of forest soils: detectability of changes in soil carbon stocks in temperate and Boreal forests.

    Science.gov (United States)

    Conen, Frauz; Zerva, Argyro; Arrouays, Dominique; Jolivet, Claude; Jarvis, Paul G; Grace, John; Mencuccini, Maurizio

    2005-01-01

    Estimating soil carbon content as the product of mean carbon concentration and bulk density can result in considerable overestimation. Carbon concentration and soil mass need to be measured on the same sample and carbon contents calculated for each individual sample before averaging. The effect of this bias is likely to be smaller (but still greater than zero) when the primary objective is to determine stock changes over time. Variance and mean carbon content are significantly and positively related to each other, although some sites showed much higher variability than predicted by this relationship, as a likely consequence of their particular site history, forest management, and micro-topography. Because of the proportionality between mean and variance, the number of samples required to detect a fixed change in soil carbon stocks varied directly with the site mean carbon content from less than 10 to several thousands across the range of carbon stocks normally encountered in temperate and Boreal forests. This raises important questions about how to derive an optimal sampling strategy across such a varied range of conditions so as to achieve the aims of the Kyoto Protocol. Overall, on carbon-poor forest sites with little or no disturbance to the soil profile, it is possible to detect changes in total soil organic carbon over time of the order of 0.5 kg (C) m(-2) with manageable sample sizes even using simple random sampling (i.e., about 50 samples per sampling point). More efficient strategies will reveal even smaller differences. On disturbed forest sites (ploughed, windthrow) this is no longer possible (required sample sizes are much larger than 100). Soils developed on coarse aeolian sediments (sand dunes), or where buried logs or harvest residues of the previous rotation are present, can also exhibit large spatial variability in soil carbon. Generally, carbon-rich soils will always require larger numbers of samples. On these sites, simple random sampling is

  13. The seasonal carbon and water balances of the Cerrado environment of Brazil: Past, present, and future influences of land cover and land use

    Science.gov (United States)

    Arantes, Arielle Elias; Ferreira, Laerte G.; Coe, Michael T.

    2016-07-01

    The Brazilian savanna (known as Cerrado) is an upland biome made up of various vegetation types from herbaceous to arboreal. In this paper, MODIS remote sensing vegetation greenness from the Enhanced Vegetation Index (EVI) and evapotranspiration (ET) data for the 2000-2012 period were analyzed to understand the differences in the net primary productivity (NPP-proxy), carbon, and the evaporative flux of the major Cerrado natural and anthropic landscapes. The understanding of the carbon and evaporative fluxes of the main natural and anthropic vegetation types is of fundamental importance in studies regarding the impacts of land cover and land use changes in the regional and global climate. The seasonal dynamics of EVI and ET of the main natural and anthropic vegetation types of the Cerrado biome were analyzed using a total of 35 satellite-based samples distributed over representative Cerrado landscapes. Carbon and water fluxes were estimated for different scenarios, such as, a hypothetical unconverted Cerrado, 2002 and 2050 scenarios based on values derived from literature and on the PROBIO land cover and land use map for the Cerrado. The total growing season biomass for 2002 in the Cerrado region was estimated to be 28 gigatons of carbon and the evapotranspiration was 1336 gigatons of water. The mean estimated growing season evapotranspiration and biomass for 2002 was 576 Gt of water and 12 Gt of carbon for pasture and croplands compared to 760 Gt of water and 15 Gt of carbon for the Cerrado natural vegetation. In a modeled future scenario for the year 2050, the ET flux from natural Cerrado vegetation was 394 Gt less than in 2002 and 991 Gt less than in an unconverted scenario, with only natural vegetation, while the carbon was 8 Gt less than in 2002 and 21 Gt less than in this hypothetical pre-conversion Cerrado. On the other hand, the sum of the pasture and cropland ET flux increased by 405 Gt in 2050 relative to 2002 and the carbon by 11 Gt of carbon. Given the

  14. Energy and water balance studies of a snow cover during snowmelt period at a high arctic site

    Science.gov (United States)

    Bruland, O.; Maréchal, D.; Sand, K.; Killingtveit, Å.

    The predicted global warming is supposed to have an enhanced effect on the arctic regions. How this will influence the water, carbon dioxide and methane balances in the European arctic tundra is the objective of the EU-funded project ``Understanding Land Surface Physical Processes in the Arctic'' (LAPP), to which where SINTEF is one of several contributors. The snow cover is one of the limiting factors for these exchange processes and knowledge of how it behaves and will behave under a different climate is important. Data collected for water and energy balance studies in an area close to Ny-Ålesund at 79°N at Svalbard are the basis of this study. Measurements during the ablation periods since 1992 show an average air temperature for the periods of 2.1°C, an average incoming shorwave radiation of 230W/m2 and an average measured runoff intensity of 14mm/day with a maximum of 68mm/day. Three models of different complexity are tested in order to simulate the water and energy balance of a snow cover on the arctic tundra. The three models are: a complex numerical model (CROCUS), a simple energy balance model and a temperature index model. The simulations were carried out for the melt periods in 1992 and 1996 as these two periods represent very different meteorological conditions. The results of these simulations exposed weaknesses in all the models. The energy balance model lacks calculation of cold content in the snowpack. This influences both the outgoing longwave radiation and the timing of the melt. Due to the effect of compensating errors in the simulations, CROCUS performed better than the simple energy balance model but also this model has problems with the simulation of outgoing longwave radiation. The temperature index model does not perform well for snowmelt studies in regions were radiation is the main driving energy source for the melt.

  15. Mass and energy balance of the carbonization of babassu nutshell as affected by temperature

    Directory of Open Access Journals (Sweden)

    Thiago de Paula Protásio

    2014-03-01

    Full Text Available The objective of this work was to evaluate the carbonization yield of babassu nutshell as affected by final temperature, as well as the energy losses involved in the process. Three layers constituting the babassu nut, that is, the epicarp, mesocarp and endocarp, were used together. The material was carbonized, considering the following final temperatures: 450, 550, 650, 750, and 850ºC. The following were evaluated: energy and charcoal yields, pyroligneous liquid, non-condensable gases, and fixed carbon. The use of babassu nutshell can be highly feasible for charcoal production. The yield of charcoal from babassu nutshell carbonization was higher than that reported in the literature for Eucalyptus wood carbonization, considering the final temperature of 450ºC. Charcoal and energy yields decreased more sharply at lower temperatures, with a tendency to stabilize at higher temperatures. The energy yields obtained can be considered satisfactory, with losses between 45 and 52% (based on higher heating value and between 43 and 49% (based on lower heating value at temperatures ranging from 450 to 850ºC, respectively. Yields in fixed carbon and pyroligneous liquid are not affected by the final carbonization temperature.

  16. Dynamic balancing of isoprene carbon sources reflects photosynthetic and photorespiratory responses to temperature stress.

    Science.gov (United States)

    Jardine, Kolby; Chambers, Jeffrey; Alves, Eliane G; Teixeira, Andrea; Garcia, Sabrina; Holm, Jennifer; Higuchi, Niro; Manzi, Antonio; Abrell, Leif; Fuentes, Jose D; Nielsen, Lars K; Torn, Margaret S; Vickers, Claudia E

    2014-12-01

    The volatile gas isoprene is emitted in teragrams per annum quantities from the terrestrial biosphere and exerts a large effect on atmospheric chemistry. Isoprene is made primarily from recently fixed photosynthate; however, alternate carbon sources play an important role, particularly when photosynthate is limiting. We examined the relative contribution of these alternate carbon sources under changes in light and temperature, the two environmental conditions that have the strongest influence over isoprene emission. Using a novel real-time analytical approach that allowed us to examine dynamic changes in carbon sources, we observed that relative contributions do not change as a function of light intensity. We found that the classical uncoupling of isoprene emission from net photosynthesis at elevated leaf temperatures is associated with an increased contribution of alternate carbon. We also observed a rapid compensatory response where alternate carbon sources compensated for transient decreases in recently fixed carbon during thermal ramping, thereby maintaining overall increases in isoprene production rates at high temperatures. Photorespiration is known to contribute to the decline in net photosynthesis at high leaf temperatures. A reduction in the temperature at which the contribution of alternate carbon sources increased was observed under photorespiratory conditions, while photosynthetic conditions increased this temperature. Feeding [2-(13)C]glycine (a photorespiratory intermediate) stimulated emissions of [(13)C1-5]isoprene and (13)CO2, supporting the possibility that photorespiration can provide an alternate source of carbon for isoprene synthesis. Our observations have important implications for establishing improved mechanistic predictions of isoprene emissions and primary carbon metabolism, particularly under the predicted increases in future global temperatures. PMID:25318937

  17. Radionuclide trap studies using porous carbon

    International Nuclear Information System (INIS)

    Towards import substitute, an attempt has been made to synthesise porous carbon by acidic sucrose solution route for use as trap material for cesium isotopes. The radionuclide trap experiments have been carried out to study the uptake of fission product cesium (137Cs) using reticulated vitreous carbon (RVC) and home made porous carbon (HMPC) in static sodium system. The trapping efficiency and distribution coefficient have been measured and compared. (author)

  18. Benthic biogeochemical cycling, nutrient stoichiometry, and carbon and nitrogen mass balances in a eutrophic freshwater bay

    Science.gov (United States)

    Klump, J.V.; Fitzgerald, S.A.; Waplesa, J.T.

    2009-01-01

    Green Bay, while representing only ,7% of the surface area and ??1.4% of the volume of Lake Michigan, contains one-third of the watershed of the lake, and receives approximately one-third of the total nutrient loading to the Lake Michigan basin, largely from the Fox River at the southern end of the bay. With a history of eutrophic conditions dating back nearly a century, the southern portion of the bay behaves as an efficient nutrient and sediment trap, sequestering much of the annual carbon and nitrogen input within sediments accumulating at up to 1 cm per year. Depositional fluxes of organic matter varied from ??0.1 mol C m-2 yr-1 to >10 mol C m-2 yr-1 and were both fairly uniform in stoichiometric composition and relatively labile. Estimates of benthic recycling derived from pore-water concentration gradients, whole-sediment incubation experiments, and deposition-burial models of early diagenesis yielded an estimated 40% of the carbon and 50% of the nitrogen recycled back into the overlying water. Remineralization was relatively rapid with ??50% of the carbon remineralized within <15 yr of deposition, and a mean residence time for metabolizable carbon and nitrogen in the sediments of 20 yr. On average, organic carbon regeneration occurred as 75% CO2, 15% CH4, and 10% dissolved organic carbon (DOC). Carbon and nitrogen budgets for the southern bay were based upon direct measurements of inputs and burial and upon estimates of export and production derived stoichiometrically from a coupled phosphorus budget. Loadings of organic carbon from rivers were ??3.7 mol m-2 yr-1, 80% in the form of DOC and 20% as particulate organic carbon. These inputs were lost through export to northern Green Bay and Lake Michigan (39%), through sediment burial (26%), and net CO2 release to the atmosphere (35%). Total carbon input, including new production, was 4.54 mol m-2 C yr-1, equivalent to ??10% of the gross annual primary production. Nitrogen budget terms were less well quantified

  19. Experimental study of liquid carbon

    Science.gov (United States)

    Kondratyev, A. M.; Korobenko, V. N.; Rakhel, A. D.

    2016-07-01

    Direct measurements of the functional dependencies of the electric resistivity and the molar volume on enthalpy and pressure have been performed for graphite and liquid carbon. It has been found that for graphite at the pressures P  ⩽  1 GPa the isochoric temperature coefficient of resistance is positive, while for liquid carbon it is negative over the entire pressure range investigated where P  =  0.5–3.5 GPa. These observations probably indicate that graphite is a metal whereas liquid carbon is not a metal, so that the melting of graphite under such pressures coincides with a metal-to-nonmetal transition.

  20. Carbon stocks, greenhouse gas emissions and water balance of Sudanese savannah woodlands in relation to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Alam, S. A.

    2013-06-01

    Understanding the carbon (C) sequestration potential of drylands requires knowledge of the stocks of C in soils and biomass and on the factors affecting them. The overall aim of the study was to determine and evaluate the variation in the C stocks and water balance of Acacia savannah woodlands across the dryland (arid and semi-arid) region (10-16 deg N; 21-36 deg E) of the former Sudan (now mainly in the Republic of the Sudan) and how they are related to climatic factors and may be affected by climate change. The role played by small but numerous brick making industries on woodland deforestation in the region and greenhouse gas production was also investigated. The study region is often referred to as the gum belt because it is the world's major source of gum Arabic, which is harvested from Acacia trees. The soils in the centre and west of the region are mainly Arenosols (sandy soils) and those in the eastern part are mainly Vertisols (clay soils). The soils are C poor and often in a degraded state. This dissertation consists of a summary section and four articles (Study I, II, III and IV). Study I focuses on fuelwood consumption by the brick making industries (BMIs) and associated deforestation and greenhouse gas (GHG) emissions. In Study II the C densities (g C m-2) of the woodland tree biomass and soil (1 m) for 39 map sheets covering the study region were determined from national forest inventory data and global soil databases and the dependence on mean annual precipitation (MAP) and mean annual temperature (MAT) determined. The water balance of savannah woodlands for the same 39 map sheets was modelled in Study III and the variation in water balance components across the region evaluated. The potential impacts of climate change on woodland biomass C density and water-use (actual evapotranspiration, AET) was analysed for eight of the map sheets in Study IV. Sudanese BMIs consume a considerable amount of fuelwood that mainly comes from unsustainably managed

  1. Using motor imagery to study the neural substrates of dynamic balance

    NARCIS (Netherlands)

    Ferraye, M.U.; Debû, B.H.G.; Heil, L.; Carpenter, M.; Bloem, B.R.; Toni, I.

    2014-01-01

    This study examines the cerebral structures involved in dynamic balance using a motor imagery (MI) protocol. We recorded cerebral activity with functional magnetic resonance imaging while subjects imagined swaying on a balance board along the sagittal plane to point a laser at target pairs of differ

  2. Study of load balancing technology for EAST data management

    International Nuclear Information System (INIS)

    Highlights: • The load balancing concept is introduced into the MDSplus data service. • The new data service system based on the LVS framework and heartbeat technologies are described. • The scheduling algorithm “WLC” is used, and a software system is developed for optimizing the weight of node server. - Abstract: With the continuous renewal and increasing number of diagnostics, the EAST tokamak routinely generates ∼3 GB of raw data per pulse of the experiment, which is transferred to a centralized data management system. In order to strengthen international cooperation, all the acquired data has been converted and stored in the MDSplus servers. During the data system operation, there are some problems when a lot of client machines connect to a single MDSplus data server. Because the server process keeps the connection until the client closes its connection, a lot of server processes use a lot of network ports and consume a large amount of memory, so that the speed of access to data is very slow, but the CPU resource is not fully utilized. To improve data management system performance, many MDSplus servers will be installed on the blade server and form a server cluster to realize load balancing and high availability by using LVS and heartbeat technology. This paper will describe the details of the design and the test results

  3. Changes in Balance Strategy and Neuromuscular Control during a Fatiguing Balance Task—A Study in Perturbed Unilateral Stance

    Science.gov (United States)

    Ritzmann, Ramona; Freyler, Kathrin; Werkhausen, Amelie; Gollhofer, Albert

    2016-01-01

    Fatigue impairs sensorimotor performance, reduces spinal reflexes and affects the interaction of antagonistic muscles in complex motor tasks. Although there is literature dealing with the interference of fatigue and postural control, the interpretation is confounded by the variety of paradigms used to study it. This study aimed to evaluate the effects of postural fatigue on balance control and strategy, as well as on neuromuscular modulation, in response to postural perturbation (PERT) during a fatiguing balance task. A fatigue protocol consisting of continuous exposure to perturbations until exhaustion was executed in 24 subjects. Number of failed attempts, paths of center of pressure displacement (COP), ankle, knee, and hip joint kinematics, electromyographic activity of the soleus (SOL), tibialis anterior (TA), rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and gluteus maximus muscles (GM) and spinal excitability of SOL at the peak of the short-latency responses (SLR) were recorded after posterior PERT. The co-contraction index (CCI) was calculated for TA_SOL, VL_BF and RF_GM. (1) The number of failed attempts significantly increased while COP amplitude and velocity, as well as angular excursion at the ankle, knee and hip joints, decreased with fatigue (P PERT. The reduction in spinal excitability may either be caused by fatigue itself or by an increase in reciprocal inhibition due to augmented TA activity. PMID:27378886

  4. Conductive additive content balance in Li-ion battery cathodes: Commercial carbon blacks vs. in situ carbon from LiFePO{sub 4}/C composites

    Energy Technology Data Exchange (ETDEWEB)

    Palomares, Veronica; Goni, Aintzane; Muro, Izaskun Gil de; Rojo, Teofilo [Departamento de Quimica Inorganica, Universidad del Pais Vasco UPV/EHU, P.O. Box. 644, 48080, Bilbao (Spain); de Meatza, Iratxe; Bengoechea, Miguel [Energy Department, CIDETEC-IK4, P Miramon 196, Parque Tecnologico de San Sebastian, 20009, San Sebastian (Spain); Cantero, Igor [Departamento I+D+i Nuevas Tecnologias, CEGASA, Artapadura, 11, 01013 Vitoria-Gasteiz (Spain)

    2010-11-15

    Two samples of commercial conducting carbon black and the carbon generated in situ during LiFePO{sub 4}/C composite synthesis from citric acid are studied, with the aim of finding out whether carbon from the composite can fulfil the same function as carbon black in the electrode blend for a Li-ion battery. For this purpose, the carbon samples are analyzed by several techniques, such as X-ray diffraction, Raman spectroscopy, transmission electron microscopy, granulometry, BET specific area and conductivity measurements. Different cathode compositions and component proportions are tested for pellet and cast electrodes. Electrochemical results show that a moderate reduction of commercial carbon black content in both kinds of cathodes, by adding more LiFePO{sub 4}/C composite, enhanced the electrochemical behaviour by around 10%. In situ generated carbon can partially replace commercial conducting carbon black because its high specific surface probably enhances electrolyte penetration into the cathode, but it is always necessary to maintain a minimum amount of carbon black that provides better conductivity in order to obtain a good electrochemical response. (author)

  5. Present and Future Carbon Balance of Russia's Northern Ecosystems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chapin, F. Stuart III; Zimov, Sergei A.

    2000-08-28

    Recent increases in the seasonal amplitude of atmospheric CO{sub 2} at high latitudes suggest a widespread biospheric response to high-latitude warming. We have shown that the seasonal amplitude of net ecosystem carbon exchange by northern Siberian ecosystems is greater in disturbed than undisturbed sites, due to increased summer influx and increased winter efflux. Net carbon gain in summer and respiration in winter were greater in a cool than in a warm year, especially in disturbed sites and did not differ between high-arctic and treeline sites, suggesting that high-latitude warming, if it occurred, would have little effect or would reduce seasonal amplitude of carbon exchange. We suggest that increased disturbance contributes significantly to the amplified seasonal cycle of atmospheric CO{sub 2} at high latitudes.

  6. Using motor imagery to study the neural substrates of dynamic balance.

    Directory of Open Access Journals (Sweden)

    Murielle Ursulla Ferraye

    Full Text Available This study examines the cerebral structures involved in dynamic balance using a motor imagery (MI protocol. We recorded cerebral activity with functional magnetic resonance imaging while subjects imagined swaying on a balance board along the sagittal plane to point a laser at target pairs of different sizes (small, large. We used a matched visual imagery (VI control task and recorded imagery durations during scanning. MI and VI durations were differentially influenced by the sway accuracy requirement, indicating that MI of balance is sensitive to the increased motor control necessary to point at a smaller target. Compared to VI, MI of dynamic balance recruited additional cortical and subcortical portions of the motor system, including frontal cortex, basal ganglia, cerebellum and mesencephalic locomotor region, the latter showing increased effective connectivity with the supplementary motor area. The regions involved in MI of dynamic balance were spatially distinct but contiguous to those involved in MI of gait (Bakker et al., 2008; Snijders et al., 2011; Crémers et al., 2012, in a pattern consistent with existing somatotopic maps of the trunk (for balance and legs (for gait. These findings validate a novel, quantitative approach for studying the neural control of balance in humans. This approach extends previous reports on MI of static stance (Jahn et al., 2004, 2008, and opens the way for studying gait and balance impairments in patients with neurodegenerative disorders.

  7. Application Study of Self-balanced Testing Method on Big Diameter Rock-socketed Piles

    Directory of Open Access Journals (Sweden)

    Qing-biao WANG

    2013-07-01

    Full Text Available Through the technological test of self-balanced testing method on big diameter rock-socketed piles of broadcasting centre building of Tai’an, this paper studies and analyzes the links of the balance position selection, the load cell production and installation, displacement sensor selection and installation, loading steps, stability conditions and determination of the bearing capacity in the process of self-balanced testing. And this paper summarizes key technology and engineering experience of self-balanced testing method of big diameter rock-socketed piles and, meanwhile, it also analyzes the difficult technical problems needed to be resolved urgently at present. Conclusion of the study has important significance to the popularization and application of self-balanced testing method and the similar projects.

  8. Dynamic modelling and humus balances as tools for estimating and upscaling soil carbon stock changes in temperate cropland

    Science.gov (United States)

    Oberholzer, Hans-Rudolf; Holenstein, Hildegard; Mayer, Jochen; Leifeld, Jens

    2010-05-01

    Humus balances are simple mathematical tools used by farmers for assessing the overall performance of their management in terms of soil organic matter changes. They are based on humus reproduction factors which themselves mainly depend on crop rotation, residue management, and amount and type of organic fertilization. Dynamic models, on the other hand, are typically complex and need more detailed input data and are designed to calculate the time course of soil carbon content. In both cases, thorough validation is needed to utilize their potential for estimating carbon stock changes. We compared the results of three humus balance methods SALCA-SQ (Neyroud 1997), VDLUFA method (VDLUFA 2004), Humod (Brock et al. 2008) and the RothC model with measured soil carbon stocks in a long-term experiment in Switzerland for the period 1977-2005 (Fliessbach et al 2007). The field trial comprises various minerally and organically fertilized treatments, the latter differing in the amount and composition of organics applied. All methods were able to distinguish systematic management effects on soil organic carbon (SOC). However, only those SOC trajectories calculated with the dynamic model RothC matched measured stocks quantitatively. For both, humus balances and dynamic modelling the result strongly depended on parameterization of organic fertilizers, i.e. its stability and organic matter content. Therefore, incomplete information on the amount and composition of organic fertilizer and lack of knowledge about its potential for humus reproduction is regarded an uncertainty in both dynamic modelling and humus balance calculation, and seems to be a major drawback for the reliable application of these approaches at the regional scale. Our results stress the need for more detailed and harmonized data bases of organic fertilizer composition and application rates. References Brock C., Hoyer U., Leithold G., Hülsbergen K.-J., 2008. Entwicklung einer praxisanwendbaren Methode der

  9. The Stable Level of Glutamine synthetase 2 Plays an Important Role in Rice Growth and in Carbon-Nitrogen Metabolic Balance.

    Science.gov (United States)

    Bao, Aili; Zhao, Zhuqing; Ding, Guangda; Shi, Lei; Xu, Fangsen; Cai, Hongmei

    2015-06-04

    Glutamine synthetase 2 (GS2) is a key enzyme involved in the ammonium metabolism in plant leaves. In our previous study, we obtained GS2-cosuppressed plants, which displayed a normal growth phenotype at the seedling stage, while at the tillering stage they showed a chlorosis phenotype. In this study, to investigate the chlorosis mechanism, we systematically analyzed the plant growth, carbon-nitrogen metabolism and gene expressions between the GS2-cosuppressed rice and wild-type plants. The results revealed that the GS2-cosuppressed plants exhibited a poor plant growth phenotype and a poor nitrogen transport ability, which led to nitrogen accumulation and a decline in the carbon/nitrogen ratio in the stems. Interestingly, there was a higher concentration of soluble proteins and a lower concentration of carbohydrates in the GS2-cosuppressed plants at the seedling stage, while a contrasting result was displayed at the tillering stage. The analysis of the metabolic profile showed a significant increase of sugars and organic acids. Additionally, gene expression patterns were different in root and leaf of GS2-cosuppressed plants between the seedling and tillering stage. These results indicated the important role of a stable level of GS2 transcription during normal rice development and the importance of the carbon-nitrogen metabolic balance in rice growth.

  10. Magnetic suspension and balance system advanced study, phase 2

    Science.gov (United States)

    Boom, R. W.; Abdelsalam, M. K.; Eyssa, Y. M.; Mcintosh, G. E.

    1990-01-01

    The design improvements for the system encompass 14 or 18 external superconductive coils mounted on a 8 x 8 foot wind tunnel, a superconductive model core magnet on a holmium mandrel to fit an F-16 model, model wings of permanent magnet material Nd2Fe14B, and fiber glass epoxy structure. The Magnetic Suspension and Balance System (MSBS) advanced design is confirmed by the successful construction and test of a full size superconductive model core solenoid with holmium mandrel. The solenoid is 75 cm long and 12.6 cm in diameter and produces 6.1 tesla for a hold time of 47 minutes. An integrated coil system design of a new compact configuration without specific coils for roll or pitch shows promise of simplicity; magnet reductions of 30 percent compared to the most recent 1985 design are possible.

  11. Contribution of chloroplast biogenesis to carbon-nitrogen balance during early leaf development in rice.

    Science.gov (United States)

    Kusumi, Kensuke; Hirotsuka, Shoko; Shimada, Hiroshi; Chono, Yoko; Matsuda, Osamu; Iba, Koh

    2010-07-01

    Chloroplast biogenesis is most significant during the changes in cellular organization associated with leaf development in higher plants. To examine the physiological relationship between developing chloroplasts and host leaf cells during early leaf development, we investigated changes in the carbon and nitrogen contents in leaves at the P4 developmental stage of rice, during which leaf blade structure is established and early events of chloroplast differentiation occur. During the P4 stage, carbon content on a dry mass basis remained constant, whereas the nitrogen content decreased by 30%. Among carbohydrates, sucrose and starch accumulated to high levels early in the P4 stage, and glucose, fructose and cellulose degradation increased during the mid-to-late P4 stage. In the chloroplast-deficient leaves of the virescent-1 mutant of rice, however, the carbon and nitrogen contents, as well as the C/N ratio during the P4 stage, were largely unaffected. These observations suggest that developing rice leaves function as sink organs at the P4 stage, and that chloroplast biogenesis and carbon and nitrogen metabolism in the leaf cell is regulated independently at this stage.

  12. The impact of different management techniques on carbon balance of a pine stand after windthrow

    Science.gov (United States)

    Ziemblinska, Klaudia; Urbaniak, Marek; Merbold, Lutz; Chojnicki, Bogdan H.; Olejnik, Janusz

    2015-04-01

    Forest ecosystems cover approximately 1/3 of the global land area (and 29.8% in Poland). Since forests are constantly exposed to various types of disturbances - both natural and anthropogenic such as fires, wind, insects outbreaks or clear cuts - it is important to investigate the impact of such damages on the carbon dynamics. This becomes even more important due to the fact that future climate change will most likely result in a higher frequency and intensity of extreme climatic events. Even though wind damages cause large disturbances to forests only few places in the world exist where continuous measurements of carbon exchange (CO2) in windthrown sites are carried out. Besides the opportunity to assess the carbon dynamics following wind disturbance, there is an additional possibility of evaluating differences in post windthrow forest management practices. To fill this knowledge gap we set up two measuring stations in north-western Poland in the 500ha area of pine forest damaged by tornado in July 2012, to assess the impact of such disturbance on CO2 and H2O exchange by use of Eddy Covariance (EC) technique (Tlen I and Tlen II). Both sites are characterized by similar climatic as well as soil conditions and are located 3km from each other. While at the site Tlen I all biomass (coarse and fine woody debris were collected together with stumps) was removed and ploughed thereafter, at Tlen II only trunks and main branches were taken out from the site without ploughing. Total harvested biomass per hectare, as derived from local forest inventory, were almost 18 % higher at Tlen I than Tlen II site (where uprooted stumps were left to decompose). First analysis of the eddy covariance data shows that both sites are significant carbon sources. Emissions of carbon dioxide from the non-ploughed site (Tlen II) are higher than from the ploughed site (Tlen I). Both sites released more than 8.1 t of CO2 per ha during a three month time period (mid July to mid August 2014) after

  13. Photoluminescence Study of Carbon Nanotubes

    OpenAIRE

    Han, H. X.; Li, G. H.; Ge, W. K.; Wang, Z. P.; Xu, Z. Y.; Xie, S. S.; Chang, B H; Sun, L. F.; Wang, B S; G. Xu; Su, Z.B.

    2000-01-01

    ultiwalled carbon nanotubes, prepared by both electric arc discharge and chemical vapor deposition methods, show a strong visible light emission in photoluminescence experiments. All the samples employed in the experiments exhibit nearly same super-linear intensity dependence of the emission bands on the excitation intensity, and negligible temperature dependence of the central position and the line shapes of the emission bands. Based upon theoretical analysis of the electronic band structure...

  14. Wildland Fire, Fire Suppression, and the US Carbon Budget: a Colorado Case Study

    Science.gov (United States)

    Neff, J.; Schimel, D.; Ojima, D.; McKeown, R.; Aulenbach, S.; Hilinski, T.

    2002-12-01

    The carbon budget of the US is poorly understood. Even conservative estimates suggest that US ecosystems take up a significant amount of carbon, largely as a result of historical land use practices. In the western US, fire suppression promotes carbon sequestration but also sets the stage for major losses of carbon, as occurred during the 2002 fire season. Increases in fire due to fire suppression, increased prescribed burning and thinning, and (or) climate change could significantly affect the national carbon budget. The western US accounts for roughly half of US carbon uptake, much of it in fire-prone western coniferous forests. We used a high-resolution ecosystem model coupled to a disturbance model, forced by observed weather and fire occurrence, to simulate the direct release of carbon from western coniferous ecosystems during wildland fire. As a case study, we simulated the 2002 fire season for Colorado, and modeled regrowth for 30 years using a Climate System model scenario (including the effects of elevated atmospheric carbon dioxide) under two scenarios of management, full fire suppression and aggressive thinning. Model results suggest that fire emissions during a severe fire season, coupled with drought-induced reductions in plant productivity, can have a significant impact on the regional carbon balance, and can, under certain conditions, change the region from a net sink of carbon to a net source of atmospheric carbon. Future management for fire risk is likely to have large effects on carbon uptake. In general, continued aggressive fire suppression leads to a slowing of carbon uptake as stands mature. Aggressive thinning leads to initial losses of carbon but may sustain net primary productivity depending on the details of the management scheme, and the degree of ecosystem nutrient loss associated with the thinning techniques. Both scenarios also interact closely with future climate to determine the overall impacts of wildland fire on regional carbon

  15. A fatigue study of electrical discharge machine (EDM) strain-gage balance materials

    Science.gov (United States)

    Rhew, Ray D.

    1989-01-01

    A fatigue study was undertaken to determine how much electrical-discharge-machine (EDM) processing affected the fatigue life of balance materials: EDM and regular milling-machine (MM) samples were compared. Simulation of a typical balance stress configuration was devised for the fatigue testing in order to obtain results more closely related to balance situations. The fatigue testing of the EDM and MM specimens has indicated that the EDM technique does indeed reduce the fatigue life of 15-5PH steel, the first balance material tested. This conclusion was based on comparisons of the specimen fatigue lives with theoretical and manufacturer's data. Hence the EDM surface effects are detrimental to the fatigue life of this balance material.

  16. Evaluation of knee joint proprioception and balance of young female volleyball players: a pilot study

    OpenAIRE

    Şahin, Neşe; Bianco, Antonino; Patti, Antonino; Paoli, Antonio; Palma, Antonio; Ersöz, Gülfem

    2015-01-01

    [Purpose] The main purpose of our study was the evaluation of the effects of long-term volleyball practice on knee joint proprioception and balance of young female athletes. [Subjects and Methods] An observational case-control study was performed. The study enrolled 19 female volleyball players in the experimental group and 19 sedentary counterparts as controls. A Biodex balance system and dynamometer were used for the evaluations. The paired t-test was used to determine the significance of d...

  17. Establishing Normative Values for the Barnett Balance Assessment Tool: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Monica L. Cercone MSOTS

    2014-04-01

    Full Text Available The purpose of this study was to establish normative data for the Barnett Balance Assessment (BBA for individuals ages 18-70+ years. The BBA is a newly developed assessment tool that may address limitations present in other assessments currently used to detect balance deficits. The BBA was administered to 141 participants who had no history of medical issues that could impact balance. A review of the normative data collected indicated little variation in total assessment scores in the age categories of 18-29, 30-39, and 40-49, due to the presence of a ceiling effect. Variations existed in scores among participants in the remaining age categories (50-59, 60-69, and 70+. These findings may imply that the BBA has its greatest discriminative power in assessing individuals with impaired balance, and/or that the BBA is not sensitive enough to detect differences in individuals with mild balance impairments. The researchers suggest future studies be conducted with the BBA to establish norms with populations with known orthopedic or neurological conditions that may impair balance. Results of these studies could then be compared with the baseline data gathered in this study to determine the BBA’s usefulness in detecting balance impairments with clinical populations.

  18. Energy and carbon balances in cheatgrass, an essay in autecology. [Shortwave radiation, radiowave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hinds, W.T.

    1975-01-01

    An experiment to determine the fates of energy and carbon in cheatgrass (Bromus tectorum L.) was carried out on steep (40/sup 0/) north- and south-facing slopes on a small earth mound, using many small lysimeters to emulate swards of cheatgrass. Meteorological conditions and energy fluxes that were measured included air and soil temperatures, relative humidity, wind speed, incoming shortwave radiation, net all-wave radiation, heat flux to the soil, and evaporation and transpiration separately. The fate of photosynthetically fixed carbon during spring growth was determined by analysis of the plant tissues into mineral nutrients, crude protein, crude fat, crude fiber, and nitrogen-free extract (NFE) for roots, shoots, and seeds separately. (auth)

  19. Carbon and nitrogen balance of leaf-eating sesarmid crabs ( Neoepisesarma versicolor) offered different food sources

    Science.gov (United States)

    Thongtham, Nalinee; Kristensen, Erik

    2005-10-01

    Carbon and nitrogen budgets for the leaf-eating crab, Neoepisesarma versicolor, were established for individuals living on pure leaf diets. Crabs were fed fresh (green), senescent (yellow) and partly degraded (brown) leaves of the mangrove tree Rhizophora apiculata. Ingestion, egestion and metabolic loss of carbon and nitrogen were determined from laboratory experiments. In addition, bacterial abundance in various compartments of the crabs' digestive tract was enumerated after dissection of live individuals. Ingestion and egestion rates (in terms of dry weight) were highest, while the assimilation efficiency was poorest for crabs fed on brown leaves. The low assimilation efficiency was more than counteracted by the high ingestion rate providing more carbon for growth than for crabs fed green and yellow leaves. In any case, the results show that all types of leaves can provide adequate carbon while nitrogen was insufficient to support both maintenance (yellow leaves) and growth (green, yellow and brown leaves). Leaf-eating crabs must therefore obtain supplementary nitrogen by other means in order to meet their nitrogen requirement. Three hypotheses were evaluated: (1) crabs supplement their diet with bacteria and benthic microalgae by ingesting own faeces and/or selective grazing at the sediment surface; (2) assimilation of symbiotic nitrogen-fixing bacteria in the crabs' own intestinal system; and (3) nitrogen storage following occasional feeding on animal tissues (e.g. meiofauna and carcasses). It appears that hypothesis 1 is of limited importance for N. versicolor since faeces and sediment can only supply a minor fraction of the missing nitrogen due to physical constraints on the amount of material the crabs can consume. Hypothesis 2 can be ruled out because tests showed no nitrogen fixation activity in the intestinal system of N. versicolor. It is therefore likely that leaf-eating crabs provide most of their nitrogen requirement from intracellular deposits

  20. Changes in Balance Strategy and Neuromuscular Control during a Fatiguing Balance Task—A Study in Perturbed Unilateral Stance

    Science.gov (United States)

    Ritzmann, Ramona; Freyler, Kathrin; Werkhausen, Amelie; Gollhofer, Albert

    2016-01-01

    Fatigue impairs sensorimotor performance, reduces spinal reflexes and affects the interaction of antagonistic muscles in complex motor tasks. Although there is literature dealing with the interference of fatigue and postural control, the interpretation is confounded by the variety of paradigms used to study it. This study aimed to evaluate the effects of postural fatigue on balance control and strategy, as well as on neuromuscular modulation, in response to postural perturbation (PERT) during a fatiguing balance task. A fatigue protocol consisting of continuous exposure to perturbations until exhaustion was executed in 24 subjects. Number of failed attempts, paths of center of pressure displacement (COP), ankle, knee, and hip joint kinematics, electromyographic activity of the soleus (SOL), tibialis anterior (TA), rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and gluteus maximus muscles (GM) and spinal excitability of SOL at the peak of the short-latency responses (SLR) were recorded after posterior PERT. The co-contraction index (CCI) was calculated for TA_SOL, VL_BF and RF_GM. (1) The number of failed attempts significantly increased while COP amplitude and velocity, as well as angular excursion at the ankle, knee and hip joints, decreased with fatigue (P < 0.05). (2) Concomitantly, CCI of SOL_TA, VL_BF and RF_GM increased and spinal excitability in SOL declined. (3) Adaptations progressively augmented with progressing exhaustion and occurred in the distal prior to proximal segment. Distinctly deteriorated balance ability was accompanied by a modified neuromuscular control—the increase in co-contraction reflected by simultaneously activated antagonists is accompanied by smaller knee and hip joint excursions, indicating an elevated level of articular stiffness. These changes may be associated with an exaggerated postural rigidity and could have caused the delayed and reduced postural reactions that are reflected in the changes in COP

  1. Changes in Balance Strategy and Neuromuscular Control during a Fatiguing Balance Task-A Study in Perturbed Unilateral Stance.

    Science.gov (United States)

    Ritzmann, Ramona; Freyler, Kathrin; Werkhausen, Amelie; Gollhofer, Albert

    2016-01-01

    Fatigue impairs sensorimotor performance, reduces spinal reflexes and affects the interaction of antagonistic muscles in complex motor tasks. Although there is literature dealing with the interference of fatigue and postural control, the interpretation is confounded by the variety of paradigms used to study it. This study aimed to evaluate the effects of postural fatigue on balance control and strategy, as well as on neuromuscular modulation, in response to postural perturbation (PERT) during a fatiguing balance task. A fatigue protocol consisting of continuous exposure to perturbations until exhaustion was executed in 24 subjects. Number of failed attempts, paths of center of pressure displacement (COP), ankle, knee, and hip joint kinematics, electromyographic activity of the soleus (SOL), tibialis anterior (TA), rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and gluteus maximus muscles (GM) and spinal excitability of SOL at the peak of the short-latency responses (SLR) were recorded after posterior PERT. The co-contraction index (CCI) was calculated for TA_SOL, VL_BF and RF_GM. (1) The number of failed attempts significantly increased while COP amplitude and velocity, as well as angular excursion at the ankle, knee and hip joints, decreased with fatigue (P < 0.05). (2) Concomitantly, CCI of SOL_TA, VL_BF and RF_GM increased and spinal excitability in SOL declined. (3) Adaptations progressively augmented with progressing exhaustion and occurred in the distal prior to proximal segment. Distinctly deteriorated balance ability was accompanied by a modified neuromuscular control-the increase in co-contraction reflected by simultaneously activated antagonists is accompanied by smaller knee and hip joint excursions, indicating an elevated level of articular stiffness. These changes may be associated with an exaggerated postural rigidity and could have caused the delayed and reduced postural reactions that are reflected in the changes in COP

  2. Using a Thermokarst Bog Chronosequence to Examine Post-thaw Changes in Net Carbon Balance and the Interactions Between Permafrost, Vegetation, and Carbon

    Science.gov (United States)

    Manies, K.; Jones, M.; Waldrop, M. P.

    2015-12-01

    Northern forest soils and wetlands have served as carbon (C) sinks for thousands of years. The boreal region contains 50% of the world's soil organic C, with northern peatlands accounting for 30% of that pool. However, climate change in this region, in the form of warming air temperatures, has the potential to release a significant portion of this C due to changes in ecosystem structure and function. In particular, permafrost thaw in low-lying, moderately ice-rich areas results in the formation of collapse-scar bogs, dramatically altering the C cycle. Recent studies have shown that the transition from permafrost plateau to thermokarst bog results in the rapid loss of silvic (forest) peat, followed by a slow accumulation of C in post-thaw bog peat. Results from these studies suggest that this transition may turn these areas from net C sinks to C sources in the decades to centuries following thaw. Here we examine a bog chronosequence located within the Tanana River floodplain of Interior Alaska to determine if this pattern of C loss and gain holds true. Peat cores were taken to mineral soil from a permafrost plateau and three bogs with different ages of thaw (within the last several decades, within the last century, and within the past several centuries). All sites were located within the Bonanza Creek Long-term Ecological Research (LTER) site near Fairbanks, AK. We examined how the complex history of these thermokarst features can affect the C cycle. Macrofossil analysis reveals that most cores contained multiple cycles of permafrost aggradation and degradation, with the permafrost aggradation occurring epigenetically after peat initiated from a floodplain fen. Differences in vegetation communities that form peat, and the respective bulk densities associated with fens, permafrost plateaus, and collapse-scar bogs, resulted in different C accumulation rates. These data will provide insight into the fate of C within thermokarst bogs with complex permafrost histories in

  3. Bioanalytical effect-balance model to determine the bioavailability of organic contaminants in sediments affected by black and natural carbon.

    Science.gov (United States)

    Bräunig, Jennifer; Tang, Janet Y M; Warne, Michael St J; Escher, Beate I

    2016-08-01

    In sediments several binding phases dictate the fate and bioavailability of organic contaminants. Black carbon (BC) has a high sorptive capacity for organic contaminants and can limit their bioavailability, while the fraction bound to organic carbon (OC) is considered to be readily desorbable and bioavailable. We investigated the bioavailability and mixture toxicity of sediment-associated contaminants by combining different extraction techniques with in vitro bioanalytical tools. Sediments from a harbour with high fraction of BC, and sediments from remote, agricultural and urban areas with lower BC were treated with exhaustive solvent extraction, Tenax extraction and passive sampling to estimate total, bioaccessible and bioavailable fractions, respectively. The extracts were characterized with cell-based bioassays that measure dioxin-like activity (AhR-CAFLUX) and the adaptive stress response to oxidative stress (AREc32). Resulting bioanalytical equivalents, which are effect-scaled concentrations, were applied in an effect-balance model, consistent with a mass balance-partitioning model for single chemicals. Sediments containing BC had most of the bioactivity associated to the BC fraction, while the OC fraction played a role for sediments with lower BC. As effect-based sediment-water distribution ratios demonstrated, most of the bioactivity in the AhR-CAFLUX was attributable to hydrophobic chemicals while more hydrophilic chemicals activated AREc32, even though bioanalytical equivalents in the aqueous phase remained negligible. This approach can be used to understand the fate and effects of mixtures of diverse organic contaminants in sediments that would not be possible if single chemicals were targeted by chemical analysis; and make informed risk-based decisions concerning the management of contaminated sediments. PMID:27176940

  4. An assessment of the carbon balance of arctic tundra: comparisons among observations, process models, and atmospheric inversions

    Science.gov (United States)

    McGuire, A.D.; Christensen, T.R.; Hayes, D.; Heroult, A.; Euskirchen, E.; Yi, Y.; Kimball, J.S.; Koven, C.; Lafleur, P.; Miller, P.A.; Oechel, W.; Peylin, P.; Williams, M.

    2012-01-01

    Although arctic tundra has been estimated to cover only 8% of the global land surface, the large and potentially labile carbon pools currently stored in tundra soils have the potential for large emissions of carbon (C) under a warming climate. These emissions as radiatively active greenhouse gases in the form of both CO2 and CH4 could amplify global warming. Given the potential sensitivity of these ecosystems to climate change and the expectation that the Arctic will experience appreciable warming over the next century, it is important to assess whether responses of C exchange in tundra regions are likely to enhance or mitigate warming. In this study we compared analyses of C exchange of Arctic tundra between 1990–1999 and 2000–2006 among observations, regional and global applications of process-based terrestrial biosphere models, and atmospheric inversion models. Syntheses of the compilation of flux observations and of inversion model results indicate that the annual exchange of CO2 between arctic tundra and the atmosphere has large uncertainties that cannot be distinguished from neutral balance. The mean estimate from an ensemble of process-based model simulations suggests that arctic tundra acted as a sink for atmospheric CO2 in recent decades, but based on the uncertainty estimates it cannot be determined with confidence whether these ecosystems represent a weak or a strong sink. Tundra was 0.6 °C warmer in the 2000s compared to the 1990s. The central estimates of the observations, process-based models, and inversion models each identify stronger sinks in the 2000s compared with the 1990s. Similarly, the observations and the applications of regional process-based models suggest that CH4 emissions from arctic tundra have increased from the 1990s to 2000s. Based on our analyses of the estimates from observations, process-based models, and inversion models, we estimate that arctic tundra was a sink for atmospheric CO2 of 110 Tg C yr-1 (uncertainty between a

  5. Study of Carbon Nanotube-Substrate Interaction

    Directory of Open Access Journals (Sweden)

    Jaqueline S. Soares

    2012-01-01

    Full Text Available Environmental effects are very important in nanoscience and nanotechnology. This work reviews the importance of the substrate in single-wall carbon nanotube properties. Contact with a substrate can modify the nanotube properties, and such interactions have been broadly studied as either a negative aspect or a solution for developing carbon nanotube-based nanotechnologies. This paper discusses both theoretical and experimental studies where the interaction between the carbon nanotubes and the substrate affects the structural, electronic, and vibrational properties of the tubes.

  6. Carbon balance of a subarctic meadow under 3 r{ C warming - unravelling respiration}

    Science.gov (United States)

    Silvennoinen, Hanna; Bárcena, Téresa G.; Moni, Christophe; Szychowski, Marcin; Rajewicz, Paulina; Höglind, Mats; Rasse, Daniel P.

    2016-04-01

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, as the warming is expected to be disproportionate as compared to world averages. Northern areas contain large terrestrial carbon (C) stocks further increasing the interest in the C cycle's fate in changing climate. In 2013, we started an ecosystem warming experiment at a meadow in Eastern Finnmark, NE Norway. The meadow was on a clay soil and its vegetation was common meadow grasses and clover. Typical local agronomy was applied. The study site featured ten 4m-wide hexagonal plots, five control and five actively warmed plots in randomized complete block design. Each of the warmed plots was continuously maintained 3 ° C above its associated control plot with infrared heaters controlled by canopy thermal sensors. In 2014-2015, we measured net ecosystem exchange (NEE) and respiration twice per week during growth seasons from preinstalled collars of each site with dynamic, temperature-controlled chambers combined to an infrared analyzer. Despite warming-induced differences in yield, species composition and root biomass, neither the NEE nor the respiration responded to the warming, all sites remaining equal sinks for C. Following this observation, we carried out an additional experiment in 2015 where we aimed at partitioning the total CO2 flux to microbial and plant respiration as well as at recording the growth season variation of those parameters in situ. Here, we used an approach based on natural abundances of 13C. The δ13C signature of both autotrophic plant respiration and heterotrophic microbial respiration were obtained in targeted incubations (Snell et al. 2014). Then, the δ13C -signature of the total soil respiration was determined in the field by Keeling approach with dynamic dark chambers combined to CRDS. Proportions of autotrophic and heterotrophic components in total soil respiration were then derived based on 13C mixing model. Incubations were repeated at early, mid and

  7. Subalpine grassland carbon balance during 7 years of increased atmospheric N deposition

    OpenAIRE

    Volk, Matthias; Enderle, Jan; Bassin, Seraina

    2016-01-01

    Air pollution agents interact when affecting biological sinks for atmospheric CO2, e.g., the soil organic carbon (SOC) content of grassland ecosystems. Factors favoring plant productivity, like atmospheric N deposition, are usually considered to favor SOC storage. In a 7-year experiment in subalpine grassland under N- and O3-deposition treatment, we examined C fluxes and pools. Total N deposition was 4, 9, 14, 29 and 54 kg N ha−1 yr−1 (N4, N9, etc.); annual mean phytotoxic ...

  8. Development of Statistical Accuracy Improvement Methodology for Oil Refinery Sector's Energy and Carbon Balance and Statistical Accuracy on Japanese General Energy Statistics (Japanese)

    OpenAIRE

    KAINOU Kazunari

    2015-01-01

    Current Japanese General Energy Statistics quantifies energy and carbon balance of oil refinery sector solely by input such as crude oil and output such as gasoline, and regards the discrepancy as a statistical error and does not count energy consumption or energy origin carbon dioxide emission for the discrepancy. But issues are raised by a related committee of Ministry of the Environment that some part of the discrepancy of oil refinery sector might contain energy consumption and energy ori...

  9. COMPARATIVE STUDY ON THE EFFECT OF SQUARE STEPPING EXERCISES VERSUS BALANCE TRAINING EXERCISES ON FEAR OF FALL AND BALANCE IN ELDERLY POPULATION

    Directory of Open Access Journals (Sweden)

    Harshika Bhanusali

    2016-02-01

    Full Text Available Background: Balance is a complex process involving the reception and integration of sensory inputs and the planning and execution of movement to achieve a goal requiring upright posture. The need of the study is to compare the effect of square stepping exercises versus balance exercises on fear of falling and balance in elderly. Aims and Objectives: 1. To study the effects of square stepping exercise on older adults to improve balance impairments and reducing fear of falling. 2. To identify the effects of balance exercise on fear of falling and balance in elderly. 3. To compare effect of balance exercise and square stepping exercise and in older adults to improve balance and reducing fear of falling. Materials and Methods: 36 elderly individuals with age 60 year and above having MMSE score >24 and BBS scores of more than 41/56 with vital signs within normal range for elderly population were included in the study. Subjects with history of any neurological disease and musculoskeletal impairment that could account for possible balance impairment like CVA, Parkinson's disease, vestibular disorder, joint replacement, fractures etc, diagnosed with visual and auditory impairment, uncontrolled diabetes mellitus, unstable cardio-respiratory condition, which may affect the training procedure were excluded. Purpose of the study was explained to the subject. Written consent was taken. All participants were selected by simple random sampling and randomly divided into two groups. Group A received Square stepping exercises and group B received Balance training exercises for a period of 30 minutes with appropriate rest pause, 3 times per week for 4 weeks. Mini Mental State Examination (MMSE, Berg Balance Scale (BBS, Timed Get Up Go (TUG were used to assess cognition, balance respectively and Fall Efficacy Scale (FES was used to assess fear of falling Result: Participants in both the groups improved on BBS and TUG (p<0.0001 scores. Conclusion: The study

  10. Measurement of carbon and water balances of semiarid scrubs using transient-state closed chambers

    Science.gov (United States)

    López-Ballesteros, Ana; Pérez-Priego, Óscar; Sánchez-Cañete, Enrique P.; Serrano-Ortiz, Penélope; Domingo, Francisco; Kowalski, Andrew S.

    2013-04-01

    The measurement of canopy photosynthesis and transpiration is crucial to understand the carbon and water cycles, specially, in water-limited ecosystems. When the objective is to quantify fluxes of carbon at whole-plant level, scaling up from leaf to canopy by using multi-layer models is always a tricky approach, because of the complexity in obtaining model parameters within the canopy. Here we present a transient-state closed chamber, large enough to measure medium-size plant gas exchanges in a semiarid shrubland. Additionally, a series of tests were carried out to evaluate physical and physiological plant responses to potential environmental modifications caused by the chamber. As results, leakage had a minimal impact on flux calculations (0.9 % min-1), and chambeŕs walls adsorption of water was not detected. Furthermore, the artificial turbulence generated by fans into the chamber to facilitate air mixing did not alter the transpiration rate. The optimal duration of the calculation window was 60 s, which was the sufficient time interval to avoid the disturbance of the enclosed plant. Maximum increases in air and plant temperature were 0.6 °C min-1 and 0.9 °C min-1, respectively. Therefore, the minimal effects that the chamber generated over the physiological processes of the enclosed plant indicate that this chamber is suitable for accurate measurements of gas exchanges at whole-plant scale in typical species that conform semiarid shrubland ecosystems.

  11. Carbon dioxide gasification of carbon black: isotope study of carbonate catalysis

    International Nuclear Information System (INIS)

    Temperature-programmed reaction was used with labeled isotopes (13C and 18O) to study interactions between carbon black and potassium carbonate in pure He and 10% CO2/90% He atmospheres. Catalytic gasification precursor complexes were observed. Carbon and oxygen-bearing carbon surface groups interacted with the carbonate above 500 K to form surface complexes. Between 500 and 950 K, and in the presence of gaseous CO2, the complexes participated in C and O exchange with the gas phase while oxygen atoms within the complexes also exchanged with those on the carbon surface. As the temperature rose, the complexes decomposed, with CO2 the initial product. Decomposition started around 500 K in pure He, and around 950 K in CO2/He. Catalytic gasification began only after decomposition of significant portions of the complexes. Elemental potassium formed, and the active catalyst appears to alternate between being potassium metal and a potassium-oxygen-carbon complex. Potassium carbonate is not part of the catalytic cycle. 20 references, 10 figures

  12. Balance between carbon gain and loss under long-term drought: impacts on foliar respiration and photosynthesis in Quercus ilex L.

    Science.gov (United States)

    Sperlich, D; Barbeta, A; Ogaya, R; Sabaté, S; Peñuelas, J

    2016-02-01

    Terrestrial carbon exchange is a key process of the global carbon cycle consisting of a delicate balance between photosynthetic carbon uptake and respiratory release. We have, however, a limited understanding how long-term decreases in precipitation induced by climate change affect the boundaries and mechanisms of photosynthesis and respiration. We examined the seasonality of photosynthetic and respiratory traits and evaluated the adaptive mechanism of the foliar carbon balance of Quercus ilex L. experiencing a long-term rainfall-exclusion experiment. Day respiration (Rd) but not night respiration (Rn) was generally higher in the drought treatment leading to an increased Rd/Rn ratio. The limitation of mesophyll conductance (gm) on photosynthesis was generally stronger than stomatal limitation (gs) in the drought treatment, reflected in a lower gm/gs ratio. The peak photosynthetic activity in the drought treatment occurred in an atypical favourable summer in parallel with lower Rd/Rn and higher gm/gs ratios. The plant carbon balance was thus strongly improved through: (i) higher photosynthetic rates induced by gm; and (ii) decreased carbon losses mediated by Rd. Interestingly, photosynthetic potentials (Vc,max, Jmax, and TPU) were not affected by the drought treatment, suggesting a dampening effect on the biochemical level in the long term. In summary, the trees experiencing a 14-year-long drought treatment adapted through higher plasticity in photosynthetic and respiratory traits, so that eventually the atypical favourable growth period was exploited more efficiently.

  13. Development and study on automatic balancer based on counter weight by magnetic force

    Institute of Scientific and Technical Information of China (English)

    Liu Heng; Fan Hongwei; Jing Minqing; Wang Renchao; Zhi Jingjuan

    2013-01-01

    Rotating machines are very sensitive to mass unbalance which has a harmful effect on its running accuracy and service life.Therefore,a variety of dynamic balancing methods and devices are studied to reduce the vibration caused by mass unbalance.On-line active balancing is a new balancing procedure which is more convenient and precise than the previous methods.In this paper,an electromagnetic balancer based on ring coils and permanent magnets is presented.The balancer has a simple structure and the self-locking function without clutch,and transfers power by the non-contact electromagnetic field.In order to justify the rationality of its design,a two-dimension(2D)electromagnetic finite element model is conducted to verify that this magnetic circuit has no flux leakage and saturation.A three-dimension (3D) 1/10 model of the balancer is built to obtain the self-locking torque and driving torque.Based on the research work above,an electromagnetic balancer is developed.By testing the balaneer using COCO80,it is verified effective to reduce the rotor unbalance at the speed of 1300 r/min.

  14. Postural Balance Following Aerobic Fatigue Tests: A Longitudinal Study Among Young Athletes.

    Science.gov (United States)

    Steinberg, Nili; Eliakim, Alon; Zaav, Aviva; Pantanowitz, Michal; Halumi, Monder; Eisenstein, Tamir; Meckel, Yoav; Nemet, Dan

    2016-01-01

    General fatigue can cause aggravation of postural balance, with increased risk for injuries. The present longitudinal study aimed to evaluate the postural balance of young athletes following field aerobic tests throughout 1 year of training. Thirty children from a sports center in Nazareth, participating in a 3 times/week training program (specific to basketball, soccer, or athletic training), were assessed. Postural balance parameters were taken before, immediately after, and 10 min after a 20 m shuttle-run aerobic test, at 3 time points during 1 training year (Start/Y, Mid/Y, and End/Y). Fitness improved at the Mid/Y and End/Y compared to Start/Y. Postural balance significantly deteriorated immediately after the aerobic test and improved significantly in the 10-min testing in all 3 time points, with significant deterioration in the End/Y compared with the Start/Y. In conclusions, postural balance deteriorates immediately after aerobic exercises, and at the end of the year. To better practice drills related to postural balance and possibly to prevent injuries, it is best for young athletes to properly rest immediately following aerobic exercises and to practice postural balance mainly at the beginning and at the middle of the training year.

  15. Postural Balance Following Aerobic Fatigue Tests: A Longitudinal Study Among Young Athletes.

    Science.gov (United States)

    Steinberg, Nili; Eliakim, Alon; Zaav, Aviva; Pantanowitz, Michal; Halumi, Monder; Eisenstein, Tamir; Meckel, Yoav; Nemet, Dan

    2016-01-01

    General fatigue can cause aggravation of postural balance, with increased risk for injuries. The present longitudinal study aimed to evaluate the postural balance of young athletes following field aerobic tests throughout 1 year of training. Thirty children from a sports center in Nazareth, participating in a 3 times/week training program (specific to basketball, soccer, or athletic training), were assessed. Postural balance parameters were taken before, immediately after, and 10 min after a 20 m shuttle-run aerobic test, at 3 time points during 1 training year (Start/Y, Mid/Y, and End/Y). Fitness improved at the Mid/Y and End/Y compared to Start/Y. Postural balance significantly deteriorated immediately after the aerobic test and improved significantly in the 10-min testing in all 3 time points, with significant deterioration in the End/Y compared with the Start/Y. In conclusions, postural balance deteriorates immediately after aerobic exercises, and at the end of the year. To better practice drills related to postural balance and possibly to prevent injuries, it is best for young athletes to properly rest immediately following aerobic exercises and to practice postural balance mainly at the beginning and at the middle of the training year. PMID:26731202

  16. Aggregates reduce transport distance of soil organic carbon: are our balances correct?

    Directory of Open Access Journals (Sweden)

    Y. Hu

    2014-06-01

    Full Text Available The effect of soil erosion on global carbon cycling, especially as a source or sink for greenhouse gases, has been the subject of intense debate. The controversy arises mostly from the lack of information on the fate of eroded soil organic carbon (SOC whilst in-transit from the site of erosion to the site of longer-term deposition. Solving this controversy requires an improved understanding of the transport distance of eroded SOC, which is principally related to the settling velocity of sediment fractions that carry the eroded SOC. Although settling velocity has already been included in some erosion models, it is often based on mineral particle size distribution. For aggregated soils, settling velocities are affected by their actual aggregate size rather than by mineral particle size distribution. Aggregate stability is, in turn, strongly influenced by SOC. In order to identify the effect of aggregation of source soil on the transport distance of eroded SOC, and its susceptibility to mineralization after transport and temporary deposition, a rainfall simulation was carried out on a silty loam. Both the eroded sediments and undisturbed soil were fractionated into six different size classes using a settling tube apparatus according to their settling velocities. Weight, SOC concentration and instantaneous respiration rates were measured for each of the six class fractions. Our results indicate that: (1 41% of the eroded SOC was transported with coarse aggregates that would be likely re-deposited down eroding hillslopes, rather than with fine particles likely transferred to water courses; (2 erosion was prone to accelerate the mineralization of eroded SOC, and thus might contribute more CO2 to the atmosphere than current estimates which often ignore potential effects of aggregation; (3 preferential deposition of SOC-rich coarse aggregates potentially causes an increase of SOC remaining in the colluvial system and a reduction of SOC flux to the

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

    Directory of Open Access Journals (Sweden)

    Abir U Igamberdiev

    2016-07-01

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

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

    Science.gov (United States)

    Igamberdiev, Abir U.; Eprintsev, Alexander T.

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium. PMID:27471516

  19. Interactions between biomass energy technologies and nutrient and carbon balances at the farm level

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, Uffe; Molt Petersen, B. [Danish Inst. of Agricultural Science, Dept. of Agroecology, Tjele (Denmark)

    2006-08-15

    Biomass energy is by far the largest renewable energy source in the world (IEA Renewable information (www.iea.org)). Biomass utilisation is closely linked to management and sustainability issues of forestry and agriculture. Carbon is extracted from forests and agriculture to bioenergy facilities, from where it is partly or fully emitted as CO{sub 2} and thus no longer available for sustaining soil organic matter content. Nutrients are extracted as well and, depending of the conversion technology, they may be recycled to farmland or lost as gaseous emissions. Thus, we must be able to describe these effects, and to suggest strategies to alleviate adverse effects on farm sustainability and on the environment. By choosing intelligent combinations of cropping systems and energy conversion technologies, win-win solutions may be achieved. This paper illustrates, via three cases, some agricultural impacts of choice of biomass technology and describes an intriguing possibility for recycling municipal or industrial wastes through the bioenergy chain. (au)

  20. Effect of climate change, CO2 trends, nitrogen addition, and land-cover and management intensity changes on the carbon balance of European grasslands.

    Science.gov (United States)

    Chang, Jinfeng; Ciais, Philippe; Viovy, Nicolas; Vuichard, Nicolas; Herrero, Mario; Havlík, Petr; Wang, Xuhui; Sultan, Benjamin; Soussana, Jean-François

    2016-01-01

    Several lines of evidence point to European managed grassland ecosystems being a sink of carbon. In this study, we apply ORCHIDEE-GM a process-based carbon cycle model that describes specific management practices of pastures and the dynamics of carbon cycling in response to changes in climatic and biogeochemical drivers. The model is used to simulate changes in the carbon balance [i.e., net biome production (NBP)] of European grasslands over 1991-2010 on a 25 km × 25 km grid. The modeled average trend in NBP is 1.8-2.0 g C m(-2)  yr(-2) during the past two decades. Attribution of this trend suggests management intensity as the dominant driver explaining NBP trends in the model (36-43% of the trend due to all drivers). A major change in grassland management intensity has occurred across Europe resulting from reduced livestock numbers. This change has 'inadvertently' enhanced soil C sequestration and reduced N2 O and CH4 emissions by 1.2-1.5 Gt CO2 -equivalent, offsetting more than 7% of greenhouse gas emissions in the whole European agricultural sector during the period 1991-2010. Land-cover change, climate change and rising CO2 also make positive and moderate contributions to the NBP trend (between 24% and 31% of the trend due to all drivers). Changes in nitrogen addition (including fertilization and atmospheric deposition) are found to have only marginal net effect on NBP trends. However, this may not reflect reality because our model has only a very simple parameterization of nitrogen effects on photosynthesis. The sum of NBP trends from each driver is larger than the trend obtained when all drivers are varied together, leaving a residual - nonattributed - term (22-26% of the trend due to all drivers) indicating negative interactions between drivers.

  1. Using motor imagery to study the neural substrates of dynamic balance

    OpenAIRE

    Murielle Ursulla Ferraye; Bettina Debû; Lieke Heil; Mark Carpenter; Bastiaan Roelof Bloem; Ivan Toni

    2014-01-01

    This study examines the cerebral structures involved in dynamic balance using a motor imagery (MI) protocol. We recorded cerebral activity with functional magnetic resonance imaging while subjects imagined swaying on a balance board along the sagittal plane to point a laser at target pairs of different sizes (small, large). We used a matched visual imagery (VI) control task and recorded imagery durations during scanning. MI and VI durations were differentially influenced by the sway accuracy ...

  2. Exergame design for elderly users: the case study of SilverBalance

    OpenAIRE

    Gerling, Kathrin; Schild, Jonas; Masuch, Maic

    2010-01-01

    In this paper, we discuss chances and challenges of game design for an elderly audience with a focus on the development of safe and usable exertion games for frail senior citizens. Based on an analysis of theoretical constraints, we conducted a case study which implements different balance tasks for elderly players featuring the Nintendo Wii Balance Board which encourages users to actively engage in game play. Furthermore, we tested the feasibility of the board as input device for our case st...

  3. Soil aggregates, organic matter turnover and carbon balance in a Mediterranean eroded vineyard

    Science.gov (United States)

    Novara, Agata; Lo Papa, Giuseppe; Dazzi, Carmelo; Gristina, Luciano; Cerdà, Artemi

    2014-05-01

    The carbon cycle is being affected by the human impacts (Novara et al., 2011; Yan-Gui et al., 2013), and one of those is the intensification in the soil erosion in agriculture land (Cerdà et al., 2009; García Orenes et al., 2009). Vineyards also are affected by the human activities (Fernández Calviño, 2012). Vineyards in Sicily are cultivated on 110.000 ha, 10% of which on >10% slope. Deficiencies of soil organic matter are typical of the semi arid Mediterranean environment especially where traditional intensive cropping practices are adopted (Novara et al., 2012; 2013). These practices in vineyards could lead soil to intensive erosion processes (Novara et al., 2011). The fate of SOC under erosion processes is difficult to understand because of the influence of the erosion impact on SOC pathway, which depends on the different features of the process involved (detachment, transport and/or deposition). Soil erosion must be considered a net C source (Lal, 2003), as eroded soils have lower net primary productivity (NPP) (Dick and Gregorich, 2004) caused by reduction in the effective rooting depth and all in all determining decline in soil quality. Breakdown of aggregates and soil dispersion expose SOM to microbial/enzymatic processes and chemical soil properties (Dimoyiannis, 2012; Kocyigit and Demirci, 2012). Moreover the light fraction, transported by runoff, is labile and easily mineralized determining CO2 emission in the atmosphere (Jacinthe and Lal, 2004). Therefore, the carbon pool is lower in eroded than in un-eroded soil scapes and the rate of mineralization of soil organic matter is higher in sediments than in original soil. In this survey we show a research conducted on a slope sequence of three soil profiles in an irrigated vineyard located in Sambuca di Sicilia, Italy (UTM33-WGS84: 4169367N; 325011E). The SOC content was measured at depth intervals of 10 cm up to a depth of 60 cm in each pedon. Wet aggregate-size fractions with no prior chemical

  4. Carbon and Isotopic Mass Balance Models of Oasis Valley-Fortymile Canyon Groundwater Basin, Southern Nevada

    Science.gov (United States)

    White, Art F.; Chuma, Nancy J.

    1987-04-01

    Environmental isotopes and carbon chemistry provide means of differentiating various recharge areas, flow paths, and ages of groundwater in portions of the Nevada Test Site and vicinity. Regional δD/δ18O trends are offset from the present-day meteoric line by a deuterium depletion of 5‰, suggesting paleoclimatic changes. Partial pressures of CO2 and the 18O and 13C data indicate solubility and isotopic equilibrium between the gas and water in the soil zone with progressive exchange with underlying groundwater in the shallow alluvium of Oasis Valley. Application of a closed system CO2 model using the EQ3NR/EQ6 reaction path simulator successfully reproduces chemical compositions observed in the alluvium in the Amargosa Desert and in the deep tuff aquifer beneath Pahute Mesa and Yucca Mountain. Initial PCO2 input to the soil zone during recharge was calculated to range from 0.03 to 0.10 atm, which is comparable to measured soil CO2 pressures in Oasis Valley. Results are compared for 14C ages using the δ13C dilution correction and a mass action correction term relating predicted and calculated ionic activity products of CaCO3. Results are generally comparable with discrepancies attributed to anomalous δ13C values.

  5. Near-neutral carbon dioxide balance at a seminatural, temperate bog ecosystem

    Science.gov (United States)

    Hurkuck, Miriam; Brümmer, Christian; Kutsch, Werner L.

    2016-02-01

    The majority of peatlands in the temperate zone is subjected to drainage and agricultural land use and have been found to be anthropogenic emission hot spots for greenhouse gases. At the same time, many peatlands receive increased atmospheric nitrogen (N) deposition by intensive agricultural practices. Here we provide eddy covariance measurements determining net ecosystem carbon dioxide (CO2) exchange at a protected but moderately drained ombrotrophic bog in Northwestern Germany over three consecutive years. The region is dominated by intensive agricultural land use with total (wet and dry) atmospheric N deposition being about 25 kg N ha-1 yr-1. The investigated peat bog was a small net CO2 sink during all three years ranging from -9 to -73 g C m-2 yr-1. We found temperature- and light-dependent ecosystem respiration (Reco) and gross primary production, respectively, but only weak correlations to water table depths despite large interannual and seasonal variability. Significant short-term effects of atmospheric N deposition on CO2 flux components could not be observed, as the primary controlling factors for N deposition and C sequestration, i.e., fertilization of adjacent fields as well as temperature and light availability, respectively, exceeded potential interactions between the two.

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

    Science.gov (United States)

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

    2012-01-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO2) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  7. Subalpine grassland carbon balance during 7 years of increased atmospheric N deposition

    Science.gov (United States)

    Volk, Matthias; Enderle, Jan; Bassin, Seraina

    2016-07-01

    Air pollution agents interact when affecting biological sinks for atmospheric CO2, e.g., the soil organic carbon (SOC) content of grassland ecosystems. Factors favoring plant productivity, like atmospheric N deposition, are usually considered to favor SOC storage. In a 7-year experiment in subalpine grassland under N- and O3-deposition treatment, we examined C fluxes and pools. Total N deposition was 4, 9, 14, 29 and 54 kg N ha-1 yr-1 (N4, N9, etc.); annual mean phytotoxic O3 dose was 49, 65 and 89 mmol m-2 projected leaf area. We hypothesized that between years SOC of this mature ecosystem would not change in control treatments and that effects of air pollutants are similar for plant yield, net ecosystem productivity (NEP) and SOC content, leading to SOC content increasing with N deposition. Cumulative plant yield showed a significant N and N × N effect (+38 % in N54) but no O3 effect. In the control treatment SOC increased significantly by 9 % in 7 years. Cumulative NEP did show a strong, hump-shaped response pattern to N deposition with a +62 % increase in N14 and only +39 % increase in N54 (N effect statistically not significant, N × N interaction not testable). SOC had a similar but not significant response to N, with highest C gains at intermediate N deposition rates, suggesting a unimodal response with a marginal (P = 0.09) N × N interaction. We assume the strong, pollutant-independent soil C sink developed as a consequence of the management change from grazing to cutting. The non-parallel response of SOC and NEP compared to plant yield under N deposition is likely the result of increased respiratory SOC losses, following mitigated microbial N-limitation or priming effects, and a shift in plant C allocation leading to smaller C input from roots.

  8. The Impact of a Mild Sub-Critical Hydrothermal Carbonization Pretreatment on Umbila Wood. A Mass and Energy Balance Perspective

    OpenAIRE

    Carlos Alberto Cuvilas; Efthymios Kantarelis; Weihong Yang

    2015-01-01

    Over the last years, the pretreatment of biomass as a source of energy has become one of the most important steps of biomass conversion. In this work the effect of a mild subcritical hydrothermal carbonization of a tropical woody biomass was studied. Results indicate considerable change in carbon content from 52.78% to 65.1%, reduction of oxygen content from 41.14% to 28.72% and ash slagging and fouling potential. Even though decarboxylation, decarbonylation and dehydration reactions take pla...

  9. Soil water balance scenario studies using predicted soil hydraulic parameters

    NARCIS (Netherlands)

    Nemes, A.; Wösten, J.H.M.; Bouma, J.; Várallyay, G.

    2006-01-01

    Pedotransfer functions (PTFs) have become a topic drawing increasing interest within the field of soil and environmental research because they can provide important soil physical data at relatively low cost. Few studies, however, explore which contributions PTFs can make to land-use planning, in ter

  10. Balancing Act: Student Valuation and Cultural Studies Composition Textbooks

    Science.gov (United States)

    Rendleman, Eliot

    2011-01-01

    Composition scholars have contributed many theoretical analyses that WPAs and teachers might apply to first-year composition textbooks in order to make informed decisions about book adoption and implementation. As they offer critiques of the ideological effects of FYC books, many of these studies call composition textbooks "tools" without…

  11. Brazil Low Carbon Case Study : Waste

    OpenAIRE

    World Bank

    2010-01-01

    This report synthesis the findings for the waste sector of a broader study, the Brazil low carbon study, which was undertaken by the World Bank in its initiative to support Brazil's integrated effort towards reducing national and global emissions of Greenhouse Gases (GHG) while promoting long term development. The purpose of the present report is to assist in the preparation of public poli...

  12. A STUDY OF OXIDANTS-ANTIOXIDANTS BALANCE IN ASTHMATIC PATIENTS

    Directory of Open Access Journals (Sweden)

    Lokendra

    2014-06-01

    Full Text Available : This study was done to observe the serum/plasma oxidant-antioxidant status among asthmatic patients. Plasma MDA (Malon-di-aldehyde, an oxidant and Serum SOD (superoxide dismutase, an antioxidant, were assayed among asthmatic patients and their mean values were compared with healthy volunteer controls. Values were also observed in different age groups. The difference in mean pMDA level was found statistically significantly among cases and control, higher among asthmatic patients. Likewise, s-SOD level was significantly reduced among asthmatic patients. Clearly, there was an imbalance between oxidants and antioxidants levels among asthmatic patients and this consideration may be helpful in proper planning of basket of anti-asthma interventions. Future studies are recommended.

  13. System Dynamic Modelling for a Balanced Scorecard: A Case Study

    DEFF Research Database (Denmark)

    Nielsen, Steen; Nielsen, Erland Hejn

    of optimum or 'steady-state-condition. We, also demonstrate through three different scenarios how different variables influence the optimum time that normally also influence decision making. Findings - The results shows how profit, and ROCE (Return-On-Capital-Employed) are influenced by three chosen...... first attempt to study an analytical version of BSC and to make inferences concerning some optimal or rational behaviour of an assumed relationship between different indicators and perspectives. The credibility or benefit of the model is insight into the finality of a model but also as a teaching......Purpose - The purpose of this research is to make an analytical model of the BSC foundation by using a dynamic simulation approach for a 'hypothetical case' model, based on only part of an actual case study of BSC. Design/methodology/approach - The model includes five perspectives and a number...

  14. Carbon balance in conterminous U.S. forests based on historic changes in climate, atmospheric composition, and disturbances

    Science.gov (United States)

    Zhang, F.; Chen, J.; Ju, W.; Shen, S.; Pan, Y.; Birdsey, R.; He, L.

    2010-12-01

    Forest ecosystems are the dominant contributors to the carbon sink in terrestrial ecosystems. Although many studies have already explored the effects of non-disturbance factors such as climate and atmospheric composition on the terrestrial carbon cycle, few studies have systematically considered the impact of disturbance on the forest carbon cycle at regional scale, mostly because of the lack of spatially and temporally explicit disturbance data. In this study, we show, for the first time, the spatio-temporal distribution of the carbon sink in conterminous U.S. forests from 1901 to 2006 modeled with the consideration of both disturbance and non-disturbance effects using the Integrated Terrestrial Ecosystem Carbon Model (InTEC). The application of this model is possible owing to the recently available national forest age data in 2000. Our results show that the annual net primary productivity of conterminous U.S. forests increased from 1476 Tg C yr-1 in the early 20th century to 1892 Tg C yr-1 in the early 21st century, whereas the net biome productivity increased from -32.9 Tg C yr-1 to 422.5 Tg C yr-1 in the same period. The overall results indicate that forest sink extended from North regions to South and Southeast regions and the maximum sink occurred in the Kentucky and Tennesee states after 1990. Fig. 1. (a-c) Carbon (C) dynamics of the conterminous U.S. forests over last 106 years from 1901 to 2006 (a-c); (d-f) Spatial distribution of carbon sources/sinks in the forest ecosystems of the conterminous U.S. in the 1980s, 1990s and 2000s. Table 1 Changes of carbon storages of forest ecosystem in different regions of the conterminous U.S. over last 106 years from 1901 to 2006 (Unit: Tg C yr-1). (1) Northeast (NE); (2) Northern Lake (NL); (3) North Plain (NP); (4) Pacific Northwest (PN); (5) Pacific Southwest (PS); (6) Rocky Mountain North (RMN); (7) Rocky Mountain South (RMS); (8) South Central (SC); (9) Southeast (SE).

  15. Alpine ecosystem vulnerability to climate change on the Tibetan Plateau: Global implications for carbon balance, regional consequences for local pastoralists

    Science.gov (United States)

    Hopping, K. A.; Klein, J. A.; Hu, J.; Kang, S.

    2010-12-01

    The Tibetan Plateau is predicted to undergo climate warming much greater than the global average, as well as shifts in its currently monsoon-dominated precipitation regime. These changes will likely affect the vegetation composition, carbon balance, and nutrient cycling of this alpine, social-ecological system. In 2009 we established a fully factorial experiment to test ecosystem responses to predicted climate changes on the Tibetan Plateau. Our experiment site (4870 m) is located in the foothills of the Nyanchenthanglha Mountains, where local pastoralists graze their livestock. The site is representative of central Tibet’s alpine meadow ecosystems, with the turf-forming sedge, Kobresia pygmaea, as both the dominant species and preferred forage of yaks. Our climate treatments are spring snow addition, which is added at 1-m depth to simulate severe snowstorms, and warming with open top chambers, which elevate air temperatures by an average of 1.2 degrees Celsius. The climate treatments are fully crossed with controlled grazing by yaks, which represents the primary livelihood practice of herders at our study site and throughout Tibet’s grasslands. To better understand the ecosystem shifts that may occur under climate change in this alpine system and to elucidate the drivers of these shifts, we collected data from a suite of measurements in each of our plots. Using a LiCOR 6400 infrared gas analyzer, we measured CO2 fluxes at 4 periods throughout the growing season to obtain values for net ecosystem productivity (NEP), ecosystem respiration, and gross primary productivity. We also measured available nitrogen (N) across three distinct moisture regimes (snowmelt, dry-down, and monsoon). Finally, we quantified changes in vegetation composition and recorded air and soil temperature and soil moisture throughout the growing season. After two years of applying treatments, our findings suggest that Tibet’s alpine grasslands are particularly vulnerable to climate change

  16. Balance study of the fate of 15N fertilizer

    International Nuclear Information System (INIS)

    An interim report is presented on a series of experiments with wooden box-type lysimeters (60 cm x 60 cm x 70 cm) loaded with a sandy soil, a loess soil and straw-amended soil. The lysimeters support crops rotated over a five-year period to be studied - potato, barley, sugar-beet, barley (with winter rape) and finally (1979) potato. Each lysimeter received split applications of urea at total rates of 0, 50 or 100 kg.ha-1. The effects of soil residues of the herbicide monolinuron were also studied. The report deals with data collected during the first three years of the planned experiments (1975 - 1977 inclusive). 15N-labelled urea (47 atom 15N% excess) was initially used but in some experiments this was followed by applications of unlabelled urea in order to study the fate of the residual 15N in the subsequent years. The results to date indicated that in the first year highest recoveries in the plant of the applied 15N obtained on the sandy soil. The low recoveries of 15N in the subsequent years when unlabelled urea was supplied also indicated significant storage by soil or root organic matter of the applied 15N. Compared with the control (zero application of urea nitrogen), potato took up more total nitrogen in the presence of fertilizer including more of the unlabelled soil pool nitrogen. Analyses of the soil profiles in terms of total soil nitrogen and fertilizer-derived nitrogen (on the basis of 15N assays) indicated leaching of the labelled nitrogen down the soil profile in all cases during the three-year period. Analysis of NO3-N in leachates confirmed the presence of labelled urea-derived nitrogen. (author)

  17. CO{sub 2} enrichment and carbon partitioning to phenolics: do plant responses accord better with the protein competition or the growth differentiation balance models?

    Energy Technology Data Exchange (ETDEWEB)

    Mattson, W.J. [Forestry Sciences Lab., Rhinelander, WI (United States); Julkunen-Tiitto, R. [Univ. of Joensuu, Biology Dept., Joensuu (Finland); Herms, D.A. [Ohio State Univ., Dept. of Entmology, Wooster, OH (United States)

    2005-11-01

    Rising levels of atmospheric CO{sub 2} can alter plant growth and partitioning to secondary metabolites. The protein competition model (PCM) and the extended growth/differentiation balance model (GDB{sub e}) are similar but alternative models that address ontogenetic and environmental effects on whole-plant carbon partitioning to the phenylpropanoid biosynthetic pathway, making many divergentpredictins. To test the validity of the models, we compare plant responses to one key prediction: if CO{sub 2} enrichment simultaneously stimulates both photosynthesis and growth, then PCM predicts that partitioning to phenolic compounds will decline, whereas GDB{sub e} generally predicts the opposite. Elevated CO{sub 2} (at 548 ppm) increased the biomass growth (ca 23%) as well as the net photosynthesis (ca 13%) of 1-year-old potted paper birch, Betula papyrifera Marsch., in a free air carbon dioxide enrichment study (FACE) in northern Wisconsin. Concomitantly, elevated CO{sub 2} increased carbon partitioning to all measured classes of phenolics (Folin-Denis phenolics, HPLC low molecular weight phenolics (i.e. cinnamic acid derivatives, flavonol flycosides, and flavon-3-ols), condensed tannins, and acid-detergent lignin) in leaves. In stem tissues, tannins and lignin increased, but F-D phenolics did not. In root tissues, F-D phenolics, and tannins increased, but lignin did not. The data suggest that CO{sub 2} enrichment stimulated pathway-wide increase in carbon partitioning to phenylpropanoids. High CO{sub 2} plants had 11.8% more F-D phenolics, 19.3% more tannin, and 10% more lignin than ambient plants after adjusting for plant mass via analysis of covariance. In general, the results unequivocally support the predictions of the GDB{sub e} model. By way of contrast, results from many parallel studies on FACE trembling aspen, Populus tremuloides Michx., suggest that although 2 enrichment has consistently stimulated both photosynthesis and growth, it apparently did not

  18. Nitrogen and carbon source balance determines longevity, independently of fermentative or respiratory metabolism in the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Santos, Júlia; Leitão-Correia, Fernanda; Sousa, Maria João; Leão, Cecília

    2016-04-26

    Dietary regimens have proven to delay aging and age-associated diseases in several eukaryotic model organisms but the input of nutritional balance to longevity regulation is still poorly understood. Here, we present data on the role of single carbon and nitrogen sources and their interplay in yeast longevity. Data demonstrate that ammonium, a rich nitrogen source, decreases chronological life span (CLS) of the prototrophic Saccharomyces cerevisiae strain PYCC 4072 in a concentration-dependent manner and, accordingly, that CLS can be extended through ammonium restriction, even in conditions of initial glucose abundance. We further show that CLS extension depends on initial ammonium and glucose concentrations in the growth medium, as long as other nutrients are not limiting. Glutamine, another rich nitrogen source, induced CLS shortening similarly to ammonium, but this effect was not observed with the poor nitrogen source urea. Ammonium decreased yeast CLS independently of the metabolic process activated during aging, either respiration or fermentation, and induced replication stress inhibiting a proper cell cycle arrest in G0/G1 phase. The present results shade new light on the nutritional equilibrium as a key factor on cell longevity and may contribute for the definition of interventions to promote life span and healthy aging. PMID:27072582

  19. Nitrogen and carbon source balance determines longevity, independently of fermentative or respiratory metabolism in the yeast Saccharomyces cerevisiae

    Science.gov (United States)

    Santos, Júlia; Leitão-Correia, Fernanda

    2016-01-01

    Dietary regimens have proven to delay aging and age-associated diseases in several eukaryotic model organisms but the input of nutritional balance to longevity regulation is still poorly understood. Here, we present data on the role of single carbon and nitrogen sources and their interplay in yeast longevity. Data demonstrate that ammonium, a rich nitrogen source, decreases chronological life span (CLS) of the prototrophic Saccharomyces cerevisiae strain PYCC 4072 in a concentration-dependent manner and, accordingly, that CLS can be extended through ammonium restriction, even in conditions of initial glucose abundance. We further show that CLS extension depends on initial ammonium and glucose concentrations in the growth medium, as long as other nutrients are not limiting. Glutamine, another rich nitrogen source, induced CLS shortening similarly to ammonium, but this effect was not observed with the poor nitrogen source urea. Ammonium decreased yeast CLS independently of the metabolic process activated during aging, either respiration or fermentation, and induced replication stress inhibiting a proper cell cycle arrest in G0/G1 phase. The present results shade new light on the nutritional equilibrium as a key factor on cell longevity and may contribute for the definition of interventions to promote life span and healthy aging. PMID:27072582

  20. Enzymes for carbon sequestration: neutron crystallographic studies of carbonic anhydrase

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, S. Z., E-mail: zfisher@lanl.gov; Kovalevsky, A. Y. [Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Domsic, J. [Department of Biochemistry and Molecular Biology, PO Box 100245, University of Florida, Gainesville, FL 32610 (United States); Mustyakimov, M. [Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Silverman, D. N. [Department of Pharmacology and Therapeutics, PO Box 100267, University of Florida, Gainesville, FL 32610 (United States); McKenna, R. [Department of Biochemistry and Molecular Biology, PO Box 100245, University of Florida, Gainesville, FL 32610 (United States); Langan, P. [Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2010-11-01

    The first neutron crystal structure of carbonic anhydrase is presented. The structure reveals interesting and unexpected features of the active site that affect catalysis. Carbonic anhydrase (CA) is a ubiquitous metalloenzyme that catalyzes the reversible hydration of CO{sub 2} to form HCO{sub 3}{sup −} and H{sup +} using a Zn–hydroxide mechanism. The first part of catalysis involves CO{sub 2} hydration, while the second part deals with removing the excess proton that is formed during the first step. Proton transfer (PT) is thought to occur through a well ordered hydrogen-bonded network of waters that stretches from the metal center of CA to an internal proton shuttle, His64. These waters are oriented and ordered through a series of hydrogen-bonding interactions to hydrophilic residues that line the active site of CA. Neutron studies were conducted on wild-type human CA isoform II (HCA II) in order to better understand the nature and the orientation of the Zn-bound solvent (ZS), the charged state and conformation of His64, the hydrogen-bonding patterns and orientations of the water molecules that mediate PT and the ionization of hydrophilic residues in the active site that interact with the water network. Several interesting and unexpected features in the active site were observed which have implications for how PT proceeds in CA.

  1. The application of the Wilhelmy balance to the measurement of electrocapillary effects in molten carbonate

    NARCIS (Netherlands)

    Peelen, W.H.A.; Hemmes, K.; Kamping, H.; Bos, M.; Wit, de J.H.W.

    1998-01-01

    In this work, the Wilhelmy method is shown to be very suitable for studying electrocapillary effects in molten salts. Unlike the optical methods usually used this method, can easily be used in automated set-ups. High accuracies of 0.3° in the contact angle were easily obtained. First experiments are

  2. Neck pain and postural balance among workers with high postural demands - a cross-sectional study

    DEFF Research Database (Denmark)

    Jørgensen, Marie B.; Skotte, Jørgen H.; Holtermann, Andreas;

    2011-01-01

    Neck pain is related to impaired postural balance among patients and is highly prevalent among workers with high postural demands, for example, cleaners. We therefore hypothesised, that cleaners with neck pain suffer from postural dysfunction. This cross-sectional study tested if cleaners with neck...... pain have an impaired postural balance compared with cleaners without neck pain. Postural balance of 194 cleaners with (n = 85) and without (N = 109) neck pain was studied using three different tests. Success or failure to maintain the standing position for 30 s in unilateral stance was recorded....... Participants were asked to stand on a force platform for 30 s in the Romberg position with eyes open and closed. The centre of pressure of the sway was calculated, and separated into a slow (rambling) and fast (trembling) component. Subsequently, the 95% confidence ellipse area (CEA) was calculated...

  3. Efficient cycles for carbon capture CLC power plants based on thermally balanced redox reactors

    KAUST Repository

    Iloeje, Chukwunwike

    2015-10-01

    © 2015 Elsevier Ltd. The rotary reactor differs from most alternative chemical looping combustion (CLC) reactor designs because it maintains near-thermal equilibrium between the two stages of the redox process by thermally coupling channels undergoing oxidation and reduction. An earlier study showed that this thermal coupling between the oxidation and reduction reactors increases the efficiency by up to 2% points when implemented in a regenerative Brayton cycle. The present study extends this analysis to alternative CLC cycles with the objective of identifying optimal configurations and design tradeoffs. Results show that the increased efficiency from reactor thermal coupling applies only to cycles that are capable of exploiting the increased availability in the reduction reactor exhaust. Thus, in addition to the regenerative cycle, the combined CLC cycle and the combined-regenerative CLC cycle are suitable for integration with the rotary reactor. Parametric studies are used to compare the sensitivity of the different cycle efficiencies to parameters like pressure ratio, turbine inlet temperature, carrier-gas fraction and purge steam generation. One of the key conclusions from this analysis is that while the optimal efficiency for regenerative CLC cycle was the highest of the three (56% at 3. bars, 1200. °C), the combined-regenerative cycle offers a trade-off that combines a reasonably high efficiency (about 54% at 12. bars, 1200. °C) with much lower gas volumetric flow rate and consequently, smaller reactor size. Unlike the other two cycles, the optimal compressor pressure ratio for the regenerative cycle is weakly dependent on the design turbine inlet temperature. For the regenerative and combined regenerative cycles, steam production in the regenerator below 2× fuel flow rate improves exhaust recovery and consequently, the overall system efficiency. Also, given that the fuel side regenerator flow is unbalanced, it is more efficient to generate steam from the

  4. Two Pilot Studies of the Effect of Bicycling on Balance and Leg Strength among Older Adults

    Directory of Open Access Journals (Sweden)

    Chris Rissel

    2013-01-01

    Full Text Available Objectives. Study 1 examines whether age-related declines in balance are moderated by bicycling. Study 2 tests whether regular cycling can increase leg strength and improve balance. Methods. Study 1: a cross-sectional survey of 43 adults aged 44–79 was conducted. Leg strength was measured, and Balance was measured using the choice stepping reaction time (CSRT test (decision time and response time, leg strength and timed single leg standing. Study 2: 18 older adults aged 49–72 were recruited into a 12-week cycling program. The same pre- and postmeasures as used in Study 1 were collected. Results. Study 1: participants who had cycled in the last month performed significantly better on measures of decision time and response time. Study 2: cycling at least one hour a week was associated with significant improvements in balance (decision time and response time and timed single leg standing. Conclusions. Cycling by healthy older adults appears promising for improving risk factors for falls.

  5. Long-term nutrient fertilization and the carbon balance of permanent grassland: any evidence for sustainable intensification?

    Science.gov (United States)

    Fornara, Dario A.; Wasson, Elizabeth-Anne; Christie, Peter; Watson, Catherine J.

    2016-09-01

    Sustainable grassland intensification aims to increase plant yields while maintaining the ability of soil to act as a sink rather than sources of atmospheric CO2. High biomass yields from managed grasslands, however, can be only maintained through long-term nutrient fertilization, which can significantly affect soil carbon (C) storage and cycling. Key questions remain about (1) how long-term inorganic vs. organic fertilization influences soil C stocks, and (2) how soil C gains (or losses) contribute to the long-term C balance of managed grasslands. Using 43 years of data from a permanent grassland experiment, we show that soils not only act as significant C sinks but have not yet reached C saturation. Even unfertilized control soils showed C sequestration rates of 0.35 Mg C ha-1 yr-1 (i.e. 35 g C m-2 yr-1; 0-15 cm depth) between 1970 and 2013. High application rates of liquid manure (i.e. cattle slurry) further increased soil C sequestration to 0.86 Mg C ha-1 yr-1 (i.e. 86 g C m-2 yr-1) and a key cause of this C accrual was greater C inputs from cattle slurry. However, average coefficients of slurry-C retention in soils suggest that 85 % of C added yearly through liquid manure is lost possibly via CO2 fluxes and organic C leaching. Inorganically fertilized soils (i.e. NPK) had the lowest C-gain efficiency (i.e. unit of C gained per unit of N added) and lowest C sequestration (similar to control soils). Soils receiving cattle slurry showed higher C-gain and N-retention efficiencies compared to soils receiving NPK or pig slurry. We estimate that net rates of CO2-sequestration in the top 15 cm of the soil can offset 9-25 % of GHG (greenhouse gas) emissions from intensive management. However, because of multiple GHG sources associated with livestock farming, the net C balance of these grasslands remains positive (9-12 Mg CO2-equivalent ha-1 yr-1), thus contributing to climate change. Further C-gain efficiencies (e.g. reduced enteric fermentation and use of feed

  6. A Flexible Hybrid Model of Life Cycle Carbon Balance for Loblolly Pine (Pinus taeda L.) Management Systems

    OpenAIRE

    Carlos A. Gonzalez-Benecke; Rafael De La Torre; Martin, Timothy A.; Eric J. Jokela

    2011-01-01

    In this study we analyzed the effects of silvicultural treatments on carbon (C) budgets in Pinus taeda L. (loblolly pine) plantations in the southeastern United States. We developed a hybrid model that integrated a widely used growth and yield model for loblolly pine with published allometric and biometric equations to simulate in situ C pools. The model used current values of forest product conversion efficiencies and forest product decay rates to calculate ex situ C pools. Using the model t...

  7. A correlational study of scoliosis and trunk balance in adult patients with mandibular deviation.

    Directory of Open Access Journals (Sweden)

    Shuncheng Zhou

    Full Text Available Previous studies have confirmed that patients with mandibular deviation often have abnormal morphology of their cervical vertebrae. However, the relationship between mandibular deviation, scoliosis, and trunk balance has not been studied. Currently, mandibular deviation is usually treated as a single pathology, which leads to poor clinical efficiency. We investigated the relationship of spine coronal morphology and trunk balance in adult patients with mandibular deviation, and compared the finding to those in healthy volunteers. 35 adult patients with skeletal mandibular deviation and 10 healthy volunteers underwent anterior X-ray films of the head and posteroanterior X-ray films of the spine. Landmarks and lines were drawn and measured on these films. The axis distance method was used to measure the degree of scoliosis and the balance angle method was used to measure trunk balance. The relationship of mandibular deviation, spine coronal morphology and trunk balance was evaluated with the Pearson correlation method. The spine coronal morphology of patients with mandibular deviation demonstrated an "S" type curve, while a straight line parallel with the gravity line was found in the control group (significant difference, p1°, while the control group had a normal trunk balance (imbalance angle <1°. There was a significant difference between the two groups (p<0.01. The degree of scoliosis and shoulder imbalance correlated with the degree of mandibular deviation, and presented a linear trend. The direction of mandibular deviation was the same as that of the lateral bending of thoracolumbar vertebrae, which was opposite to the direction of lateral bending of cervical vertebrae. Our study shows the degree of mandibular deviation has a high correlation with the degree of scoliosis and trunk imbalance, all the three deformities should be clinically evaluated in the management of mandibular deviation.

  8. Carbon balance and productivity of Lemna gibba, a candidate plant for CELSS

    Science.gov (United States)

    Gale, J.; Smernoff, D. T.; Macler, B. A.; MacElroy, R. D.

    The photosynthesis and productivity of Lemna gibba were studied with a view to its use in Controlled Ecological Life Support Systems (CELSS). Photosynthesis of L. gibba floating on the nutrient solution could be driven by light coming from either above or below. Light from below was about 75% as effective as from above when the stand was sparse, but much less so with dense stands. High rates of photosynthesis (ca. 800 ηmol CO2-g dry weight (DW)-1 s-1) were measured at 750 μmol m-2 s-1 PPF and 1500 μmol mol-1 CO2. This was attained at densities up to 660 g fresh weight (FW) . m-2 with young cultures. After a few days growth under these conditions, and at higher densities, the rate of photosynthesis dropped to less than 25% of the initial value. This drop was only partly alleviated by thinning the stand or by introducing a short dark period at high temperature (26°C). Despite the drop in the rate of photosynthesis, maximum yields were obtained in batch cultures grown under continuous light, constant temperature and high [CO2]. Plant protein content was less than reported for field grown Lemna. When the plants were harvested daily, maintaining a stand density of 600 g FW m-2, yields of 18 g DW . m-2 d-1 were obtained. The total dry weight of L. gibba included 40% soluble material (sugars and amino acids), 15% protein, 5% starch, 5% ash and 35% cellulose and other polymers. We conclude that a CELSS system could be designed around stacked, alternate layers of transparent Lemna trays and lamps. This would allow for 7 tiers per meter height. Based on present data from single layers, the yield of such a system is calculated to be 135 g DW. m-3 d-1 of a 100% edible, protein-rich food.

  9. A Multi-Year Comparison of No-Till Versus Conventional-Till Effects on the Carbon Balance in a Corn/Soybean Agro-Ecosystem Using Eddy Covariance

    Science.gov (United States)

    Joo, E.; Slattery, R.; Meyers, T. P.; Bernacchi, C.

    2015-12-01

    Dramatic increases in atmospheric CO2 concentrations since the industrial revolution are in large part due to the release of carbon previously stored in the soil. No-till strategies have been proposed as a means to mitigate agricultural contributions to atmospheric carbon by decreasing emissions and sequestering carbon in agricultural soils while increasing water use efficiency and soil quality. However, the effects of no-till versus conventional-till practices on carbon sequestration often vary due to difficulty in quantifying soil carbon as soil properties change with management. Eddy covariance (EC) offers a more accurate method of continuously measuring the total carbon budget and does so without relying on physical soil carbon measurements. The majority of agricultural land in the Midwestern United States is farmed using the corn/soybean rotation, making it an ideal agro-ecosystem to examine the potential of adopting no-till practices on carbon and water balances. In this study, we use EC to compare carbon and water fluxes between continuous no-till and conventional-till corn/soybean sites over several years in east central Illinois. This allows the determination and comparison of 1) net ecosystem exchange (NEE) and net biome production (NEE after accounting for grain usage); 2) water use efficiency; and 3) response to climatic variation, both at short and long time scales, between the two tillage systems. We hypothesize that both carbon uptake and water use efficiency will improve with no-till practices, which in turn will improve crop responses to environmental factors such as drought and heat stress.

  10. Theoretical study of self-balancing missiles. [design for maximum vertical or lateral accelerations

    Science.gov (United States)

    Hopkins, E. J.

    1976-01-01

    A theoretical study based on linear theory is presented for two types of 'self-balancing' missiles, designed to accelerate vertically or laterally without pitching or yawing. One type of missile had a variable-incidence wing and the other type had wing flaps to provide acceleration. The main objective of this investigation is to compare the maximum available acceleration for these self-balancing missiles with that of conventional pitching-type missiles. Ten different configurations were considered. The results indicate that self-balancing missiles with either variable wing incidence or wing flaps are feasible, but that the maximum available acceleration for these missiles is less than for a conventional pitching-type missile having the same wing and tail surfaces.

  11. Balancing dual roles in self-employed women: An exploratory study

    Directory of Open Access Journals (Sweden)

    Kirsty-Lee McLellan

    2009-04-01

    Full Text Available This study is aimed at exploring how self-employed women cope in balancing their dual roles as mothers and executives. Through the elicitation of constructs by making use of Kelly’s repertory grid technique, the personal construct system of five self-employed white women in Gauteng across varying industries was established. While being successful dual earners, they still bore the primary responsibility for nurturing their families and assuring their well-being. The successful balancing of their dual roles was attributed to the following central themes, which emerged from all the participants: quality time spent with children and family, structure and planning, coping with guilt, support structures and self-reliance, and balance between work and life.

  12. Balance and gait in older electroconvulsive therapy recipients: a pilot study

    Directory of Open Access Journals (Sweden)

    Plakiotis C

    2013-06-01

    Full Text Available Chris Plakiotis,1,2 Fay Barson,2 Bharathi Vengadasalam,3 Terry P Haines,4 Daniel W O'Connor1,2 1School of Psychology and Psychiatry, Monash University, Melbourne, VIC, Australia; 2MonashHealth, Melbourne, VIC, Australia; 3Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 4Allied Health Research Unit, Monash University and MonashHealth, Melbourne, VIC, Australia Background: Electroconvulsive therapy (ECT is commonly used to treat depression in older adults. Despite its efficacy in this regard, an associated increase in the risk of falls in this population is a downside of treatment. ECT research has focused on the incidence of falls, but its effect on balance and gait – intrinsic factors in instability and falls – has not been studied. Our aim was to examine changes in balance and gait among older adults before and after a single ECT session and explore the effect of patient-related and treatment factors on any changes found. Methods: Participants were 21 older adults requiring ECT for depression in public psychiatric services. Patients with clinically overt mobility problems (impairing test participation or increasing the risk of falls were excluded. Balance and gait testing 1 hour pre-ECT and 1, 2 and 3 hours post-ECT included: (1 steady standing test; (2 perturbation of standing balance by self-initiated movements; (3 perturbation of standing balance by an external perturbation; and (4 timed up and go test. Results: No deterioration in test performance was found, using one-way repeated measures analysis of variance. Conclusion: Balance and gait did not deteriorate immediately after ECT. Exclusion of participants with clinically overt mobility problems and falls being better attributable to factors unrelated to balance and gait (such as post-ECT confusion may account for our findings. This research does not repudiate the occurrence of ECT-related falls but calls into question the utility of introducing routine balance and gait

  13. Studies of activated carbon and carbon black for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Koetz, R.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Carbon Black and activated carbon materials providing high surface areas and a distinct pore distribution are prime materials for supercapacitor applications at frequencies < 0.5 Hz. A number of these materials were tested for their specific capacitance, surface and pore size distribution. High capacitance electrodes were manufactured on the laboratory scale with attention to ease of processability. (author) 1 fig., 1 ref.

  14. Exergames for unsupervised balance training at home: A pilot study in healthy older adults.

    Science.gov (United States)

    van Diest, M; Stegenga, J; Wörtche, H J; Verkerke, G J; Postema, K; Lamoth, C J C

    2016-02-01

    Exercise videogames (exergames) are gaining popularity as tools for improving balance ability in older adults, yet few exergames are suitable for home-based use. The purpose of the current pilot study was to examine the effects of a 6-week unsupervised home-based exergaming training program on balance performance. Ten community dwelling healthy older adults (age: 75.9 ± 7.2 years) played a newly developed ice skating exergame for six weeks at home. In the game, the speed and direction of a virtual ice skater on a frozen canal were controlled using lateral weight shifts, which were captured using Kinect. Sway characteristics during quiet standing in eyes open (EO), eyes closed (EC) and dual task (DT) conditions were assessed in time and frequency domain before, and after two, four and six weeks of training. Balance was also evaluated using the narrow ridge balance test (NRBT). Multilevel modeling was applied to examine changes in balance ability. Participants played 631 (± 124)min over the intervention period and no subjects dropped out. Balance in terms of sway characteristics improved on average by 17.4% (EO) and 23.3% (EC) after six weeks of training (p<0.05). Differences in rate of improvement (p<0.05) were observed between participants. No intervention effects were found for quiet standing in DT conditions and on the NRBT. In conclusion, the pilot study showed that unsupervised home-based exergaming is feasible in community dwelling older adults, but also that participants do not benefit equally from the program, thereby emphasizing the need for more personalized exergame training programs. PMID:27004651

  15. BALANCING ON THE BORDERLINE OF EARLY AFFECT-CONFUSION - PART 2 OF A CASE STUDY TRILOGY

    Directory of Open Access Journals (Sweden)

    Richard G. Erskine

    2013-05-01

    Full Text Available Part 2 of a case study trilogy on early affect-confusion describes the psychotherapy relationship between an angry/helpless client and the psychotherapist’s skill in balancing the “borderline” between behavioral management and affect attunement, historical inquiry and normalization, validation and shame. The therapeutic use of bifurcated questions and juxtaposition reactions is illustrated.

  16. Mass Balance Model, A study of contamination effects in AMS 14C sample analysis

    NARCIS (Netherlands)

    Prokopiou, Markella

    2010-01-01

    In this training thesis a background correction analysis, also known as mass balance model, was implemented to study the contamination effects in AMS 14C sample processing. A variety of backgrounds and standards with sizes ranging from 50 μg C to 1500 μg

  17. Step-based Exergames Used in Balance Training for Seniors: A Usability Study

    OpenAIRE

    Ystmark, Kristine Midjås

    2013-01-01

    This study explores the potential of the use of step-based exergames in balance training for senior citizens. Three exergames were tested and evaluated by healthy senior citizens to provide a basis for further development and use of these types of exergames.\

  18. A Cardiovascular Risk Reduction Program for American Indians with Metabolic Syndrome: The Balance Study

    Science.gov (United States)

    Lee, Elisa T.; Jobe, Jared B.; Yeh, Jeunliang; Ali, Tauqeer; Rhoades, Everett R.; Knehans, Allen W.; Willis, Diane J.; Johnson, Melanie R.; Zhang, Ying; Poolaw, Bryce; Rogers, Billy

    2012-01-01

    The Balance Study is a randomized controlled trial designed to reduce cardiovascular disease (CVD) risk in 200 American Indian (AI) participants with metabolic syndrome who reside in southwestern Oklahoma. Major risk factors targeted include weight, diet, and physical activity. Participants are assigned randomly to one of two groups, a guided or a…

  19. Carbon balance impacts of land use changes related to the life cycle of Malaysian palm oil-derived biodiesel

    DEFF Research Database (Denmark)

    Hansen, Sune Balle; Olsen, Stig Irving; Ujang, Zaini

    2014-01-01

    The area of oil palm plantations in Malaysia is expanding by approximately 0.14 million hectare per year, and with the increasing demand for palm oil worldwide, there is no sign of the expansions slowing down. This study aims to identify the greenhouse gas emissions associated with land conversion...... to oil palm, in a life cycle perspective.LCA methodology is applied to existing land use change data. The assessment includes the issue of temporary carbon storage in the plantations. Through quantification of emissions from state forest reserve and rubber plantation conversions, the average Malaysian...... palm oil-related land use changes are calculated.The results show that there are high emissions associated with the conversion of Malaysian state forest reserve to oil palm, whereas the conversion of rubber leaves a less significant carbon debt when indirect land use change is not included. Looking...

  20. Biomass production in agroforestry and forestry systems on salt-affected soils in South Asia: exploration of the GHG balance and economic performance of three case studies.

    Science.gov (United States)

    Wicke, Birka; Smeets, Edward M W; Akanda, Razzaque; Stille, Leon; Singh, Ranjay K; Awan, Abdul Rasul; Mahmood, Khalid; Faaij, Andre P C

    2013-09-30

    This study explores the greenhouse gas balance and the economic performance (i.e. net present value (NPV) and production costs) of agroforestry and forestry systems on salt-affected soils (biosaline (agro)forestry) based on three case studies in South Asia. The economic impact of trading carbon credits generated by biosaline (agro)forestry is also assessed as a potential additional source of income. The greenhouse gas balance shows carbon sequestration over the plantation lifetime of 24 Mg CO2-eq. ha(-1) in a rice-Eucalyptus camaldulensis agroforestry system on moderately saline soils in coastal Bangladesh (case study 1), 6 Mg CO2-eq. ha(-1) in the rice-wheat- Eucalyptus tereticornis agroforestry system on sodic/saline-sodic soils in Haryana state, India (case study 2), and 96 Mg CO2-eq. ha(-1) in the compact tree (Acacia nilotica) plantation on saline-sodic soils in Punjab province of Pakistan. The NPV at a discount rate of 10% is 1.1 k€ ha(-1) for case study 1, 4.8 k€ ha(-1) for case study 2, and 2.8 k€ ha(-1) for case study 3. Carbon sequestration translates into economic values that increase the NPV by 1-12% in case study 1, 0.1-1% in case study 2, and 2-24% in case study 3 depending on the carbon credit price (1-15 € Mg(-1) CO2-eq.). The analysis of the three cases indicates that the economic performance strongly depends on the type and severity of salt-affectedness (which affect the type and setup of the agroforestry system, the tree species and the biomass yield), markets for wood products, possibility of trading carbon credits, and discount rate.

  1. Neck pain and postural balance among workers with high postural demands - a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Sjøgaard Gisela

    2011-08-01

    Full Text Available Abstract Background Neck pain is related to impaired postural balance among patients and is highly prevalent among workers with high postural demands, for example, cleaners. We therefore hypothesised, that cleaners with neck pain suffer from postural dysfunction. This cross-sectional study tested if cleaners with neck pain have an impaired postural balance compared with cleaners without neck pain. Methods Postural balance of 194 cleaners with (n = 85 and without (N = 109 neck pain was studied using three different tests. Success or failure to maintain the standing position for 30 s in unilateral stance was recorded. Participants were asked to stand on a force platform for 30 s in the Romberg position with eyes open and closed. The centre of pressure of the sway was calculated, and separated into a slow (rambling and fast (trembling component. Subsequently, the 95% confidence ellipse area (CEA was calculated. Furthermore a perturbation test was performed. Results More cleaners with neck pain (81% failed the unilateral stance compared with cleaners without neck pain (61% (p Conclusions Postural balance is impaired among cleaners with neck pain and the current study suggests a particular role of the slow component of postural sway. Furthermore, the unilateral stance test is a simple test to illustrate functional impairment among cleaners with concurrent neck and low back pain. Trial registration ISRCTN96241850

  2. Balanced scorecard application in the health care industry: a case study.

    Science.gov (United States)

    Kocakülâh, Mehmet C; Austill, A David

    2007-01-01

    Balanced scorecards became a popular strategic performance measurement and management tool in the 1990s by Robert Kaplan and David Norton. Mainline companies accepted balanced scorecards quickly, but health care organizations were slow to adopt them for use. A number of problems face the health care industry, including cost structure, payor limitations and constraints, and performance and quality issues that require changes in how health care organizations, both profit and nonprofit, manage operations. This article discusses balanced scorecards generally from theoretical and technical views, and why they should be used by health care organizations. The authors argue that balanced scorecards are particularly applicable to hospitals, clinics, and other health care companies. Finally, the authors perform a case study of the development, implementation, and use of balance scorecards by a regional Midwestern health care system. The positive and negative aspects of the subject's balanced scorecard are discussed. Leaders in today's health care industry are under great pressure to meet their financial goals. The industry is faced with financial pressures from consumers, insurers, and governments. Inflation in the industry is much higher than it is within the overall economy. Employers can no longer bear the burden of rising group health insurance costs for its employees. Too many large companies have used bankruptcy law as a shield to reduce or shift some of their legal obligations to provide health insurance coverage to present or retired employees. Stakeholders of health care providers are demanding greater control over costs. As the segment of un- or underinsured within the United States becomes larger as a percentage of the population, voters are seriously beginning to demand some form of national health insurance, which will drastically change the health care industry. PMID:18972988

  3. Balanced scorecard application in the health care industry: a case study.

    Science.gov (United States)

    Kocakülâh, Mehmet C; Austill, A David

    2007-01-01

    Balanced scorecards became a popular strategic performance measurement and management tool in the 1990s by Robert Kaplan and David Norton. Mainline companies accepted balanced scorecards quickly, but health care organizations were slow to adopt them for use. A number of problems face the health care industry, including cost structure, payor limitations and constraints, and performance and quality issues that require changes in how health care organizations, both profit and nonprofit, manage operations. This article discusses balanced scorecards generally from theoretical and technical views, and why they should be used by health care organizations. The authors argue that balanced scorecards are particularly applicable to hospitals, clinics, and other health care companies. Finally, the authors perform a case study of the development, implementation, and use of balance scorecards by a regional Midwestern health care system. The positive and negative aspects of the subject's balanced scorecard are discussed. Leaders in today's health care industry are under great pressure to meet their financial goals. The industry is faced with financial pressures from consumers, insurers, and governments. Inflation in the industry is much higher than it is within the overall economy. Employers can no longer bear the burden of rising group health insurance costs for its employees. Too many large companies have used bankruptcy law as a shield to reduce or shift some of their legal obligations to provide health insurance coverage to present or retired employees. Stakeholders of health care providers are demanding greater control over costs. As the segment of un- or underinsured within the United States becomes larger as a percentage of the population, voters are seriously beginning to demand some form of national health insurance, which will drastically change the health care industry.

  4. Protein Requirements in Healthy Adults:A Meta-analysis of Nitrogen Balance Studies

    Institute of Scientific and Technical Information of China (English)

    LI Min; SUN Feng; PIAO Jian Hua; YANG Xiao Guang

    2014-01-01

    Objective The goal of this study was to analyze protein requirements in healthy adults through a meta-analysis of nitrogen balance studies. Methods A comprehensive search for nitrogen balance studies of healthy adults published up to October 2012 was performed, each study were reviewed, and data were abstracted. The studies were first evaluated for heterogeneity. The average protein requirements were analyzed by using the individual data of each included studies. Study site climate, age, sex, and dietary protein source were compared. Results Data for 348 subjects were gathered from 28 nitrogen balance studies. The natural logarithm of requirement for 348 individuals had a normal distribution with a mean of 4.66. The estimated average requirement was the exponentiation of the mean of the log requirement, 105.64 mg N/kg·d. No significant differences between adult age, source of dietary protein were observed. But there was significant difference between sex and the climate of the study site (P Conclusion The estimated average requirement and recommended nutrient intake of the healthy adult population was 105.64 mg N/kg·d (0.66 g high quality protein/kg·d) and 132.05 mg N/kg·d (0.83 g high quality protein/kg·d), respectively.

  5. Does carbon reduction increase sustainability? A study in wastewater treatment.

    Science.gov (United States)

    Sweetapple, Christine; Fu, Guangtao; Butler, David

    2015-12-15

    This study investigates the relationships between carbon reduction and sustainability in the context of wastewater treatment, focussing on the impacts of control adjustments, and demonstrates that reducing energy use and/or increasing energy recovery to reduce net energy can be detrimental to sustainability. Factorial sampling is used to derive 315 control options, containing two different control strategies and a range of sludge wastage flow rates and dissolved oxygen setpoints, for evaluation. For each, sustainability indicators including operational costs, net energy and multiple environmental performance measures are calculated. This enables identification of trade-offs between different components of sustainability which must be considered before implementing energy reduction measures. In particular, it is found that the impacts of energy reduction measures on sludge production and nitrogen removal must be considered, as these are worsened in the lowest energy solutions. It also demonstrates that a sufficiently large range of indicators need to be assessed to capture trade-offs present within the environmental component of sustainability. This is because no solutions provided a move towards sustainability with respect to every indicator. Lastly, it is highlighted that improving the energy balance (as may be considered an approach to achieving carbon reduction) is not a reliable means of reducing total greenhouse gas emissions.

  6. Feasibility study of tar sands conditioning for earth pressure balance tunnelling

    OpenAIRE

    Martinelli, D; D. Peila; E. Campa

    2015-01-01

    This paper presents the results of laboratory test on the feasibility of soil conditioning for earth pressure balance (EPB) excavation in a tar sand, which is a natural material never studied in this respect. The laboratory test performed is based on a procedure and methods used in previous studies with different types of soils, but for this special complex material, additional tests are also conducted to verify particular properties of the tar sands, such as the tilt test and vane shear test...

  7. A Study on Electrically Conducting Magnesia—carbon Bricks for DC EAF

    Institute of Scientific and Technical Information of China (English)

    TONGXiaojun; YANLiyi; 等

    1998-01-01

    This paper gives a brief introduction to a kind of special refractories for DC EAF-electrically conducting magnesia-carbon bricks.The application of the conductive magnesia-carbon brick as a hearth electrode is a trend of development in DC arc furnace hearth bootom because of its features of anti corrosion and easy repatching,This is a proven process already available abroad.After a study of teh effect of different amount of graphite added and pretreating temperatures on the eletric-conductivity of magnesia-carbon bricks it has been found that for a balance between electric and thermal conductivities,the proper amount of graphite to be added should be 8%-14% and the pretreatment at temperature of 1300-1500℃ will result in the formation inside the magnesia-carbon bricks of a continuous three-dimensional network of graphite and semi-coke,thus making the brick conductive.

  8. A study of orthogonal, balanced and symmetric multi-wavelets on the interval

    Institute of Scientific and Technical Information of China (English)

    GAO Xieping; ZHOU Siwang

    2005-01-01

    The construction and properties of interval multi-wavelets based on symmetric/anti-symmetric orthogonal multi-wavelets on L2(R) with arbitrary supports and multiplicity 2 are introduced. The main contributions include that (1) we study the construction of general orthogonal interval multi-wavelets which preserve the polynomial- reproduction order, and obtain the parametric expressions of interval multi-wavelets; (2) we obtain the decomposition and reconstruction formulas of interval multi-wavelets; (3) we define the "balancing" concept of interval multi-wavelets for the first time and study the construction of orthogonal balancing multi-wavelets, which have been ignored in the past; (4) we study the necessary and sufficient conditions about the symmetry of interval multi-wavelets.

  9. Synthesis of Remote Sensing and Field Observations to Model and Understand Disturbance and Climate Effects on the Carbon Balance of Oregon & Northern California

    Energy Technology Data Exchange (ETDEWEB)

    Beverly Law; David Turner; Warren Cohen; Mathias Goeckede

    2008-05-22

    The goal is to quantify and explain the carbon (C) budget for Oregon and N. California. The research compares "bottom -up" and "top-down" methods, and develops prototype analytical systems for regional analysis of the carbon balance that are potentially applicable to other continental regions, and that can be used to explore climate, disturbance and land-use effects on the carbon cycle. Objectives are: 1) Improve, test and apply a bottom up approach that synthesizes a spatially nested hierarchy of observations (multispectral remote sensing, inventories, flux and extensive sites), and the Biome-BGC model to quantify the C balance across the region; 2) Improve, test and apply a top down approach for regional and global C flux modeling that uses a model-data fusion scheme (MODIS products, AmeriFlux, atmospheric CO2 concentration network), and a boundary layer model to estimate net ecosystem production (NEP) across the region and partition it among GPP, R(a) and R(h). 3) Provide critical understanding of the controls on regional C balance (how NEP and carbon stocks are influenced by disturbance from fire and management, land use, and interannual climate variation). The key science questions are, "What are the magnitudes and distributions of C sources and sinks on seasonal to decadal time scales, and what processes are controlling their dynamics? What are regional spatial and temporal variations of C sources and sinks? What are the errors and uncertainties in the data products and results (i.e., in situ observations, remote sensing, models)?

  10. A Case Study of How Organisational Members do Affect the Balancing of Exploitation and Exploration

    DEFF Research Database (Denmark)

    Andreassen, Mads R.

    2008-01-01

    study using semi-structured interviews and observation techniques this paper explores exploitation and exploration in a Danish industrial manufacture. Findings suggest that conditions affecting the balance between exploitation and exploration activities would depend on how an organisational member......Combing operations between the main parties in integration of new products, efficiently, are in practice for most organisations a challenging task demanding strong organisational capabilities, and in accordance to literature, achieving a successfully combination would be possible through...... an organisation's ability to establish dual capabilities in terms of exploitation and exploration (March, 1991). Few studies, however, suggest a classification of which organisational conditions would support a balance allowing exploitation and exploration operating side by side. Based on a single indept case...

  11. Performance measurement using balanced scorecard: A case study of pipe industry

    OpenAIRE

    Amer Hosseini; Abolfazl Danaei

    2013-01-01

    Strategic assessment of the organizational performance in the industrial environment is one of the primary and essential prerequisites for developing improvement plans in organizations. This issue is so crucial that one of the on-going affairs in the organizations is to identify the weakness and strength points. One of the effective models for assessing the organizations performance is balance scorecard (BSC) model, which examines all the aspects of an organization. The proposed study of this...

  12. Designing a Balanced Scorecard to Measure a Bank's Performance: A Case Study

    OpenAIRE

    Sabah M. Al-Najjar; Khawla H. Kalaf

    2012-01-01

    Performance measurement systems play a key role in evaluating the strategic performance of an organization, but many managers agree that their evaluation systems do not adequately fulfill this function. Hence, in recent years a shift towards the Balanced Scorecard (BSC) has emerged as a managerial approach to evaluate the strategic performance of the organization. The purpose of this study is to contribute to the understanding of how BSC is developed and applied in evaluating the performance ...

  13. Sustainability Management with the Sustainability Balanced Scorecard in SMEs: Findings from an Austrian Case Study

    OpenAIRE

    Susanna Falle; Romana Rauter; Sabrina Engert; Rupert J. Baumgartner

    2016-01-01

    Given the economic importance of small and medium sized enterprises (SMEs) and their need for strategic sustainability management, this paper examines the concept of Sustainability Balanced Scorecard (SBSC) with respect to SMEs. This case study describes the development of an SBSC in a middle-sized Austrian brewery. The existing methods used in SBSC creation were adapted to suit the company’s specific needs. The findings show that when developing an SBSC it is important to take specific SME c...

  14. The ANIBES Study on Energy Balance in Spain: Design, Protocol and Methodology

    OpenAIRE

    Emma Ruiz; José Manuel Ávila; Adrián Castillo; Teresa Valero; Susana del Pozo; Paula Rodriguez; Javier Aranceta Bartrina; Ángel Gil; Marcela González-Gross; Ortega, Rosa M.; Lluis Serra-Majem; Gregorio Varela-Moreiras

    2015-01-01

    Energy Balance (EB) is an important topic to understand how an imbalance in its main determinants (energy intake and consumption) may lead to inappropriate weight gain, considered to be “dynamic” and not “static”. There are no studies to evaluate EB in Spain, and new technologies reveal themselves as key tools to solve common problems to precisely quantify energy consumption and expenditure at population level. The overall purpose of the ANIBES (“Anthropometry, Intake and Energy Balance”) Stu...

  15. Balancing Study and Paid Work: The Experiences of Construction Undergraduates in an Australian University

    OpenAIRE

    Helen Lingard

    2012-01-01

    A questionnaire survey was undertaken among third year studentsenrolled in the University of Melbourne’s Bachelor of Property andConstruction (BPC) programme. The survey explored students’experiences in balancing paid work with study. Hours spent in paidemployment were at least as long and, in many cases, were inexcess of hours spent at university. While work was not perceivedby students to pose a difficulty for attending lectures and tutorials,students indicated that their paid work made it ...

  16. Wii-Fit for Improving Gait and Balance in an Assisted Living Facility: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Kalpana P. Padala

    2012-01-01

    Full Text Available Objectives. To determine the effects on balance and gait of a Wii-Fit program compared to a walking program in subjects with mild Alzheimer’s dementia (AD. Methods. A prospective randomized (1 : 1 pilot study with two intervention arms was conducted in an assisted living facility with twenty-two mild AD subjects. In both groups the intervention occurred under supervision for 30 minutes daily, five times a week for eight weeks. Repeated measures ANOVA and paired t-tests were used to analyze changes. Results. Both groups showed improvement in Berg Balance Scale (BBS, Tinetti Test (TT and Timed Up and Go (TUG over 8 weeks. However, there was no statistically significant difference between the groups over time. Intragroup analysis in the Wii-Fit group showed significant improvement on BBS (P=0.003, and TT (P=0.013. The walking group showed a trend towards improvement on BBS (P=0.06 and TUG (P=0.07 and significant improvement in TT (P=0.006. Conclusion. This pilot study demonstrates the safety and efficacy of Wii-Fit in an assisted living facility in subjects with mild AD. Use of Wii-Fit resulted in significant improvements in balance and gait comparable to those in the robust monitored walking program. These results need to be confirmed in a larger, methodologically sound study.

  17. Quantum mechanical studies of carbon structures

    Energy Technology Data Exchange (ETDEWEB)

    Bartelt, Norman Charles [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Ward, Donald [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Zhou, Xiaowang [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Foster, Michael E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Schultz, Peter A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Wang, Bryan M. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Univ. of California, Riverside, CA (United States); McCarty, Kevin F. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-10-01

    Carbon nanostructures, such as nanotubes and graphene, are of considerable interest due to their unique mechanical and electrical properties. The materials exhibit extremely high strength and conductivity when defects created during synthesis are minimized. Atomistic modeling is one technique for high resolution studies of defect formation and mitigation. To enable simulations of the mechanical behavior and growth mechanisms of C nanostructures, a high-fidelity analytical bond-order potential for the C is needed. To generate inputs for developing such a potential, we performed quantum mechanical calculations of various C structures.

  18. Weed-cover versus weed-removal management in olive orchards: influence on the carbon balance at the ecosystem scale

    Science.gov (United States)

    Chamizo, Sonia; Serrano-Ortiz, Penélope; Vicente-Vicente, José Luis; Sánchez-Cañete, Enrique P.; López-Ballesteros, Ana; Kowalski, Andrew S.

    2016-04-01

    Agriculture plays an important role in the C budget at the global scale. Traditional practices based on soil tillage and applying herbicides to remove weeds have caused damage to soils and led to important losses of soil organic C and increased CO2 emissions to the atmosphere. Changing trends from traditional agriculture to conservation agriculture practices may have an important role in both C and water budgets and the transformation of agriculture from C source to C sink. The objective of this study was to analyse the effect of two treatments, weed removal by herbicides versus weed cover conservation, on the C balance in an irrigated olive orchard in SE Spain. Measurements of CO2 exchange were made from October 2014 to September 2015 using two eddy covariance towers, one for each olive crop treatment. Results show that CO2 fluxes at the ecosystem scale were similar in the two treatments during initial conditions, prior to weed growth in the soils without herbicide application (October). During the first week, daily net ecosystem exchange (NEE) was close to zero in both treatments, with values ranging from 1.06 to -0.41 g C m-2 in the weed cover treatment, and from 0.76 to -0.69 g C m-2 in the weed removal treatment. As weed growth increased, higher net CO2 assimilation was found in the treatment with weed cover. In both treatments, maximum net CO2 assimilation was found in March, with a monthly NEE of -72 and -28 g C m-2 in the treatment with and without weed cover, respectively. In May, after the weeds were cut and left on the soil, a strong increase was observed in NEE in the treatment with weed cover due to decreased CO2 assimilation and increased respiration compared to the treatment without weed cover. Therefore, soil chamber measurements showed average respiration rates of 2.57 and 1.57 μmol m-2 s-2 in the weed cover and weed removal treatment, respectively. Finally, the highest monthly NEE was registered during July, with both treatments showing a similar

  19. Digital simulation studies on long transmission line protection based on balance of energy

    Institute of Scientific and Technical Information of China (English)

    文明浩; 陈德树; 尹项根

    2001-01-01

    The protection based balance of energy is a new technique specially proposed for long transmission lines. This technique depends upon the calculation of net energy into the transmission line by two independent methods and comparing them to indicate healthy and faulty conditions. In order to study the performance and feasibility of the protection based on balance of energy, the new protection has been extensively tested by using EMTP on a long transmission line with various configurations and operating conditions (including single pole line, double circuit lines and two-phase operation). The results calculated by EMTP show that under any condition of a power system, the proposed technique has excellent performance,the viability even for high resistance ground faults and a short operation time.

  20. A Case-Control Study on the Oxidative Balance of 50% Autologous Serum Eye Drops

    Directory of Open Access Journals (Sweden)

    Patrícia Ioschpe Gus

    2016-01-01

    Full Text Available Importance. Autologous serum (AS eye drops are recommended for severe dry eye in patients with ocular surface disease. No description of the antioxidant balance of AS eye drops has been reported in the literature. Objective. This study sought to evaluate the total reactive antioxidant potential (TRAP and concentration of reactive oxygen species (ROS in samples of 50% AS eye drops and their correlations with the demographic characteristics and lifestyle habits of patients with ocular surface disease and healthy controls. Design. This was a case-control study with a 3-month follow-up period. Participants. 16 patients with severe dry eye disease of different etiologies and 17 healthy controls matched by age, gender, and race were included. Results. TRAP and ROS were detected at all evaluated times. There were no differences in the mean ROS (p=0.429 or TRAP (p=0.475 levels between cases and controls. No statistically significant differences in the concentrations of ROS or TRAPs were found at 0, 15, or 30 days (p for ROS = 0.087 and p for TRAP = 0.93. Neither the demographic characteristics nor the lifestyle habits were correlated with the oxidative balance of the 50% AS eye drops. Conclusions and Relevance. Both fresh and frozen 50% AS eye drops present antioxidant capacities and ROS in an apparently stable balance. Moreover, patients with ocular surface disease and normal controls produce equivalent AS eye drops in terms of oxidative properties.

  1. Slacklining and stroke: A rehabilitation case study considering balance and lower limb weakness.

    Science.gov (United States)

    Gabel, Charles P; Rando, Natalie; Melloh, Markus

    2016-08-18

    To ascertain the effectiveness of slacklining as a supplementary therapy for elderly stroke patients who are functionally non-progressing. This case study involved an 18-mo prospective observation of the management of an 87-year-old female stroke-patient of the left hemisphere with reduced balance, reduced lower limb muscular activation, hypertonia, and concurrent postural deficits. This entailed the initial acute care phase through to discharge to home and 18-mo final status in her original independent living setting. The introduction of slacklining as an adjunct therapy was made 12 mo post incident. Slacklining involves balance retention on a tightened band where external environmental changes cause a whole-body dynamic response to retain equilibrium. It is a complex neuromechanical task enabling individualized self-developed response strategies to be learned and adapted. This facilitates the innate process of balance retention, lower-limb and core muscle activation, and stable posture through a combination of learned motor skills and neurological system down regulation. Individuals adopt and follow established sequential motor learning stages where the acquired balance skills are achieved in a challenging composite-chain activity. Slacklining could be considered an adjunct therapy for lower limb stroke rehabilitation where function is compromised due to decreased muscle recruitment, decreased postural control and compromised balance. Initial inpatient rehabilitation involved one-month acute-care, one-month rehabilitation, and one-month transitional care prior to home discharge. A further six months of intensive outpatient rehabilitation was provided with five hourly sessions per week including:supervised and self-managed hydrotherapy, plus one individual and two group falls' prevention sessions. These were supported by daily home exercises. At 12 mo post incident, recovery plateaued, then regressed following three falls. Rehabilitation was subsequently modified

  2. Slacklining and stroke: A rehabilitation case study considering balance and lower limb weakness.

    Science.gov (United States)

    Gabel, Charles P; Rando, Natalie; Melloh, Markus

    2016-08-18

    To ascertain the effectiveness of slacklining as a supplementary therapy for elderly stroke patients who are functionally non-progressing. This case study involved an 18-mo prospective observation of the management of an 87-year-old female stroke-patient of the left hemisphere with reduced balance, reduced lower limb muscular activation, hypertonia, and concurrent postural deficits. This entailed the initial acute care phase through to discharge to home and 18-mo final status in her original independent living setting. The introduction of slacklining as an adjunct therapy was made 12 mo post incident. Slacklining involves balance retention on a tightened band where external environmental changes cause a whole-body dynamic response to retain equilibrium. It is a complex neuromechanical task enabling individualized self-developed response strategies to be learned and adapted. This facilitates the innate process of balance retention, lower-limb and core muscle activation, and stable posture through a combination of learned motor skills and neurological system down regulation. Individuals adopt and follow established sequential motor learning stages where the acquired balance skills are achieved in a challenging composite-chain activity. Slacklining could be considered an adjunct therapy for lower limb stroke rehabilitation where function is compromised due to decreased muscle recruitment, decreased postural control and compromised balance. Initial inpatient rehabilitation involved one-month acute-care, one-month rehabilitation, and one-month transitional care prior to home discharge. A further six months of intensive outpatient rehabilitation was provided with five hourly sessions per week including:supervised and self-managed hydrotherapy, plus one individual and two group falls' prevention sessions. These were supported by daily home exercises. At 12 mo post incident, recovery plateaued, then regressed following three falls. Rehabilitation was subsequently modified

  3. Measuring the impact of prescribed fire management on the carbon balance of a flatwoods ecosystem in Kissimmee, Florida

    Science.gov (United States)

    Becker, K.; Hinkle, C.

    2012-12-01

    It has been well documented that terrestrial ecosystems have a great potential to store and sequester carbon. Therefore, a former ranch land at the Disney Wilderness Preserve (DWP), Kissimmee, Florida, USA is being restored to native ecosystems and managed to preserve biodiversity and increase carbon storage. Here, we present measurements of C flux from an eddy covariance system located in a longleaf pine flatwoods ecosystem at DWP. C flux measurements were taken at the site before, during, and after a prescribed fire event. C stock measurements were also taken for aboveground biomass immediately before and after the fire, as well as one year post fire. This study indicated that this ecosystem typically serves as a net sink of C. However, the system became a net source of C immediately following the fire event, with a ~40% loss of aboveground C stock, but recovered to a net sink of C within 6 weeks of the fire. Annually this ecosystem was found to serve as a net C sink even with a prescribed fire event, with annual net ecosystem productivity (NEP) of 508 g C/m2 in a non-fire year (2010) and 237 g C/m2 in a fire year (2011). In addition to the fire, it is important to note that the growing season of 2011 was anomalously dry, which likely hindered productivity, and thus the NEP of the fire year would probably be more similar to the non-fire year under more typical hydrologic conditions. Despite the variability of rainfall between years, this study shows that the longleaf pine flatwoods ecosystem provides the service of C sequestration even in the context of frequent prescribed fire management.

  4. Carbon balance of world forests and their associated soils. Progress report, August 1, 1977-September 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Zinke, P.J.

    1978-12-01

    An initial approach was made to the evaluation of total carbon storage in various soils of tropical and temperate forests. Data from published soils analyses related to soil surveys in various regions of the world were gathered, tabulated, and coded for computer analysis. Software programs were designed to tabulate, calculate carbon storages and aggregate data as cumulative probability distributions of soil storage of carbon expressed as weight of the element per square meter to a meter depth of soil.

  5. A novel isotonic balanced electrolyte solution with 1% glucose for perioperative fluid management in children- an animal experimental pre- authorisation study Running title: A novel balanced electrolyte solution

    OpenAIRE

    Witt, Lars; Osthaus, Wilhelm Alexander; Buente, Christoph; Teich, Natascha; Hermann, Elvis; Kaske, Martin; Koppert, Wolfgang; Sümpelmann, Robert

    2010-01-01

    Abstract Background: The recommendations for perioperative maintenance fluid in children have been adapted from hypotonic to isotonic electrolyte solutions with lower glucose concentrations (1-2.5% instead of 5%) in order to avoid hyponatraemia or hyperglycaemia. Objective: The objective of this prospective animal study was to determine the margin of safety of a novel isotonic balanced electrolyte solution with 1% glucose (BS-G1) in comparison to normal saline with 1% glucose (N...

  6. A Range Correction for Icesat and Its Potential Impact on Ice-sheet Mass Balance Studies

    Science.gov (United States)

    Borsa, A. A.; Moholdt, G.; Fricker, H. A.; Brunt, Kelly M.

    2014-01-01

    We report on a previously undocumented range error in NASA's Ice, Cloud and land Elevation Satellite (ICESat) that degrades elevation precision and introduces a small but significant elevation trend over the ICESat mission period. This range error (the Gaussian-Centroid or 'G-C'offset) varies on a shot-to-shot basis and exhibits increasing scatter when laser transmit energies fall below 20 mJ. Although the G-C offset is uncorrelated over periods less than1 day, it evolves over the life of each of ICESat's three lasers in a series of ramps and jumps that give rise to spurious elevation trends of -0.92 to -1.90 cm yr(exp -1), depending on the time period considered. Using ICESat data over the Ross and Filchner-Ronne ice shelves we show that (1) the G-C offset introduces significant biases in ice-shelf mass balance estimates, and (2) the mass balance bias can vary between regions because of different temporal samplings of ICESat.We can reproduce the effect of the G-C offset over these two ice shelves by fitting trends to sample-weighted mean G-C offsets for each campaign, suggesting that it may not be necessary to fully repeat earlier ICESat studies to determine the impact of the G-C offset on ice-sheet mass balance estimates.

  7. A Study of the Effect of Preschool Children's Participation in Sensorimotor Activities on Their Understanding of the Mechanical Equilibrium of a Balance Beam

    Science.gov (United States)

    Hadzigeorgiou, Yannis; Anastasiou, Leonidas; Konsolas, Manos; Prevezanou, Barbara

    2009-01-01

    The purpose of this study was to investigate whether participation in sensorimotor activities by preschool children involving their own bodily balance while walking on a beam over the floor has an effect on their understanding of the mechanical equilibrium of a balance beam. The balance beam consisted of a horizontal stick balancing around its…

  8. Study on carbon dioxide conversion by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Hyun; Park, Geun Il; Cho, Il Hoon; Choi, Sang Do; Hong, Kwang Hee; Lee, Chang Woo

    1999-09-01

    This study was carried out to investigate the synergistic effects on the CO{sub 2} conversion by the application of semiconductor in the field of gamma-ray. Gamma-ray irradiation was performed to examine the effects of semiconductor application on CO{sub 2} conversion in water and the formation of organic material from carbonate solution. From experimental results it is clear that the supplication of semiconductor in the field of gamma-ray increases the efficiency for CO{sub 2} conversion to organic matter. Based on the obtained experimental results it is obvious that the synergistic effects of semiconductor materials in the gamma-ray field leads to increase of the CO{sub 2} conversion yield to organic matter up to 50 percent compared to the gamma-ray irradiation. The way of achieving higher activity is due to thecatalytic action of semiconductor by gamma-ray irradiation. Zr-doped TiO{sub 2} catalyst prepared by sol-gel method exhibits the higher efficiency for CO{sub 2} conversion in aqueous solution and carbonate containing solution. This effect of Zr-doping can be explained by the formation of additional defects in surface of TiO{sub 2} film. (author)

  9. Study on carbon dioxide conversion by radiation

    International Nuclear Information System (INIS)

    This study was carried out to investigate the synergistic effects on the CO2 conversion by the application of semiconductor in the field of gamma-ray. Gamma-ray irradiation was performed to examine the effects of semiconductor application on CO2 conversion in water and the formation of organic material from carbonate solution. From experimental results it is clear that the supplication of semiconductor in the field of gamma-ray increases the efficiency for CO2 conversion to organic matter. Based on the obtained experimental results it is obvious that the synergistic effects of semiconductor materials in the gamma-ray field leads to increase of the CO2 conversion yield to organic matter up to 50 percent compared to the gamma-ray irradiation. The way of achieving higher activity is due to the catalytic action of semiconductor by gamma-ray irradiation. Zr-doped TiO2 catalyst prepared by sol-gel method exhibits the higher efficiency for CO2 conversion in aqueous solution and carbonate containing solution. This effect of Zr-doping can be explained by the formation of additional defects in surface of TiO2 film. (author)

  10. SOURCE APPORTIONMENT OF PM 2.5 AND CARBON IN SEATTLE USING CHEMICAL MASS BALANCE AND POSITIVE MATRIX FACTORIZATION

    Science.gov (United States)

    Three years of PM2.5 speciated data were collected and chemically analyzed using the IMPROVE protocol at the Beacon Hill site in Seattle. The data were analyzed by the Chemical Mass Balance Version 8 (CMB8) and Positive Matrix Factorization (PMF) source apportionment models. T...

  11. Basic studies on carbon steel decontamination

    International Nuclear Information System (INIS)

    The dissolution of magnetite films grown in autoclave at high temperature on carbon steel has been performed in a dynamic loop in ammoniated citric and oxalic acid solutions at two different temperatures and constant pH. The dissolution process seems to be affected by the dual-layer oxide morphology depending on the growth conditions in the autoclave. The open-circuit potential of the specimens and the corrosion rate measured by the linear polarization method have been monitored. To this aim a particular corrosion cell and a suitable reference electrode have been set up at CISE. Polarization curves have been performed to check the electrochemical processes involved in the anodic and cathodic area. At last the effect of a corrosion inhibitor, of a complexing and a reducing agent and of temperature has also been studied. The work was carried out in the frame of a CNEN research programme for the development of the CIRENE prototype

  12. Ash recycling to spruce and beech stands effects on nutrients, growth, nitrogen dynamics and carbon balance; Askaaterfoering till gran- och bokbestaand - effekter paa naering, tillvaext, kvaevedynamik och kolbalans

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Gunnar

    2006-03-15

    Ash recycling is an important part in a modern, sustainable forestry, especially in whole-tree harvest systems. Nutrients lost at harvest are returned to the forest with the wood-ash. In the project the effects of ash treatment on needle and leaf chemistry, tree growth, soil chemistry, soil water chemistry, and carbon and nitrogen dynamics were studied on 23 Norway spruce sites in south-western Sweden and in ten European beech sites in Scania, southern Sweden. On some of the sites there were previously established ash recycling experiments, but on a majority of the sites ash recycling was performed without experimental lay-out and ash and control plots were established afterwards. The most common dose was two tons of self hardened crushed wood-ash and two tons of Mg-lime. On average seven to eight years after ash recycling the results were 1. increased exchangeable stores of base cations in the soil in the beech and the spruce stands 2. increased base saturation in the beech and the spruce stands and increased BC/Al in the spruce stands 3. increased concentrations and ratios to N of P, Ca, Zn, and S in the needles, the increased P-values are especially important since P is close to or below deficiency levels in a majority of the spruce stands 4. decreased K-concentration in the beech leaves 5. increased tree growth with on average 14 % in the ash treated spruce stands compared to the control plots 6. increased carbon and nitrogen amounts in the biomass in the spruce stands 7. tendencies towards increased amounts of carbon and nitrogen in the soil in the beech stands and no effect in the soil in the spruce stands 8. increased concentrations of Ca, Mg, and SO{sub 4} and no effect on ANC in the soil water 9. no effect on potential net mineralization but increased potential nitrification rates 10. decreased concentration of nitrate in the soil water in the beech stands and no effect in the spruce stands 11. lower system N losses in the beech stands and possibly in the

  13. Phenology, Canopy Aging and Seasonal Carbon Balance as Related to Delayed Winter Pruning of Vitis vinifera L. cv. Sangiovese Grapevines.

    Science.gov (United States)

    Gatti, Matteo; Pirez, Facundo J; Chiari, Giorgio; Tombesi, Sergio; Palliotti, Alberto; Merli, Maria C; Poni, Stefano

    2016-01-01

    Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mechanistic hypothesis underlying this work was that very late winter pruning (LWP) can achieve significant postponement of phenological stages so that ripening might occur in a cooler period and, concurrently, ripening potential can be improved due to higher efficiency and prolonged longevity of the canopy. Variability in the dynamics of the annual cycle was created in mature potted cv. Sangiovese grapevines subjected to either standard winter pruning (SWP) or late and very late winter pruning (LWP, VLWP) performed when apical shoots on the unpruned canes were at the stage of 2 and 7 unfolded leaves. Vegetative growth, phenology and canopy net CO2 exchange (NCER) were followed throughout the season. Despite LWP and VLWP induced a bud-burst delay of 17 and 31 days vs. SWP, the delay was fully offset at harvest for LWP and was reduced to 6 days in VLWP. LWP showed notably higher canopy efficiency as shorter time needed to reach maximum NCER/leaf area (22 days vs. 34 in SWP), highest maximum NCER/leaf area (+37% as compared to SWP) and higher NCER/leaf area rates from veraison to end of season. As a result, seasonal cumulated carbon in LWP was 17% higher than SWP. A negative functional relationship was also established between amount of leaf area removed at winter pruning and yield per vine and berry number per cluster. Although retarded winter pruning was not able to postpone late-season phenological stages under the warm conditions of this study, it showed a remarkable potential to limit yield while improving grape quality, thereby fostering the hypothesis that it could be used to replace time-consuming and costly cluster

  14. Phenology, canopy aging and seasonal carbon balance as related to delayed winter pruning of Vitis vinifera L. cv. Sangiovese grapevines

    Directory of Open Access Journals (Sweden)

    Matteo eGatti

    2016-05-01

    Full Text Available Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mechanistic hypothesis underlying this work was that very late winter pruning can achieve significant postponement of phenological stages so that ripening might occur in a cooler period and, concurrently, ripening potential can be improved due to higher efficiency and prolonged longevity of the canopy. Variability in the dynamics of the annual cycle was created in mature potted cv. Sangiovese grapevines subjected to either standard winter pruning (SWP or late and very late winter pruning (LWP, VLWP performed when apical shoots on the unpruned canes were at the stage of 2 and 7 unfolded leaves. Vegetative growth, phenology and canopy net CO2 exchange (NCER was followed throughout the season.Despite LWP and VLWP induced a bud-burst delay of 17 and 31 days vs. SWP, the delay was fully offset at harvest for LWP and was reduced to 6 days in VLWP. LWP showed notably higher canopy efficiency as shorter time needed to reach maximum NCER/leaf area (22 days vs 34 in SWP, highest maximum NCER/leaf area (+37% as compared to SWP and higher NCER/leaf area rates from veraison to end of season. As a result, seasonal cumulated carbon in LWP was 17% higher than SWP. A negative functional relationship was also established between amount of leaf area removed at winter pruning and yield per vine and berry number per cluster. Although retarded winter pruning was not able to postpone late-season phenological stages under the warm conditions of this study, it showed a remarkable potential to limit yield while improving grape quality, thereby fostering the hypothesis that it could be used to replace time-consuming and costly

  15. Phenology, Canopy Aging and Seasonal Carbon Balance as Related to Delayed Winter Pruning of Vitis vinifera L. cv. Sangiovese Grapevines.

    Science.gov (United States)

    Gatti, Matteo; Pirez, Facundo J; Chiari, Giorgio; Tombesi, Sergio; Palliotti, Alberto; Merli, Maria C; Poni, Stefano

    2016-01-01

    Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mechanistic hypothesis underlying this work was that very late winter pruning (LWP) can achieve significant postponement of phenological stages so that ripening might occur in a cooler period and, concurrently, ripening potential can be improved due to higher efficiency and prolonged longevity of the canopy. Variability in the dynamics of the annual cycle was created in mature potted cv. Sangiovese grapevines subjected to either standard winter pruning (SWP) or late and very late winter pruning (LWP, VLWP) performed when apical shoots on the unpruned canes were at the stage of 2 and 7 unfolded leaves. Vegetative growth, phenology and canopy net CO2 exchange (NCER) were followed throughout the season. Despite LWP and VLWP induced a bud-burst delay of 17 and 31 days vs. SWP, the delay was fully offset at harvest for LWP and was reduced to 6 days in VLWP. LWP showed notably higher canopy efficiency as shorter time needed to reach maximum NCER/leaf area (22 days vs. 34 in SWP), highest maximum NCER/leaf area (+37% as compared to SWP) and higher NCER/leaf area rates from veraison to end of season. As a result, seasonal cumulated carbon in LWP was 17% higher than SWP. A negative functional relationship was also established between amount of leaf area removed at winter pruning and yield per vine and berry number per cluster. Although retarded winter pruning was not able to postpone late-season phenological stages under the warm conditions of this study, it showed a remarkable potential to limit yield while improving grape quality, thereby fostering the hypothesis that it could be used to replace time-consuming and costly cluster

  16. Disturbance and the carbon balance of US forests: A quantitative review of impacts from harvests, fires, insects, and droughts

    Science.gov (United States)

    Williams, Christopher A.; Gu, Huan; MacLean, Richard; Masek, Jeffrey G.; Collatz, G. James

    2016-08-01

    Disturbances are a major determinant of forest carbon stocks and uptake. They generally reduce land carbon stocks but also initiate a regrowth legacy that contributes substantially to the contemporary rate of carbon stock increase in US forestlands. As managers and policy makers increasingly look to forests for climate protection and mitigation, and because of increasing concern about changes in disturbance intensity and frequency, there is a need for synthesis and integration of current understanding about the role of disturbances and other processes in governing forest carbon cycle dynamics, and the likely future of this and other sinks for atmospheric carbon. This paper aims to address that need by providing a quantitative review of the distribution, extent and carbon impacts of the major disturbances active in the US. We also review recent trends in disturbances, climate, and other global environmental changes and consider their individual and collective contributions to the US carbon budget now and in the likely future. Lastly, we identify some key challenges and opportunities for future research needed to improve current understanding, advance predictive capabilities, and inform forest management in the face of these pressures. Harvest is found to be the most extensive disturbance both in terms of area and carbon impacts, followed by fire, windthrow and bark beetles, and lastly droughts. Collectively these lead to the gross loss of about 200 Tg C y- 1 in live biomass annually across the conterminous US. At the same time, the net change in forest carbon stocks is positive (190 Tg C y- 1), indicating not only forest resilience but also an apparently large response to growth enhancements such as fertilization by CO2 and nitrogen. Uncertainty about disturbance legacies, disturbance interactions, likely trends, and global change factors make the future of the US forest carbon sink unclear. While there is scope for management to enhance carbon sinks in US forests

  17. Developing and using a balanced scorecard: a case study with SWOT analysis.

    Science.gov (United States)

    Gumbus, Andra; Lussier, Robert N

    2003-01-01

    Have you tried to measure your laboratory's performance lately? Do you measure and assess financial results, customer satisfaction, internal process efficiency, and learning and growth? If any of these metrics are missing from your performance measurement system, you are not using the latest management tool that is sweeping the health-care industry--the balanced scorecard (BSC). This article begins with a discussion of the BSC and why you should use it in your laboratory, followed by SWOT analysis to assess the strengths, weaknesses, opportunities, and threats (SWOT) a BSC offers your laboratory. A laboratory case study is then presented to assist you in developing and using a BSC in your laboratory.

  18. A study on laser power balance in a multi-step ionization process of atoms

    International Nuclear Information System (INIS)

    Based on rate equation a theoretical study on laser power balance in a resonance multi-step ionization process of atoms has been presented in this paper. The calculation results made for a typical three-level atom show that there is an optimization laser power assignment when the total pumping laser power is limited, and under the optimization laser power assignment the ionization probability of a three-level atom can reach its maximum value. This conclusion is very different from that obtained under saturation excitation conditions. The method used here can be applied to more complicated multi-step ionization process of atoms. (authors)

  19. A mass balance study of the phytoremediation of perchloroethylene-contaminated groundwater

    OpenAIRE

    James, C Andrew; Xin, Gang; Doty, Sharon L.; Muiznieks, Indulis; Newman, Lee; Strand, Stuart E

    2009-01-01

    A mass balance study was performed under controlled field conditions to investigate the phytoremediation of perchloroethylene (PCE) by hybrid poplar trees. Water containing 7–14 mg L−1 PCE was added to the test bed. Perchloroethylene, trichloroethylene, and cis-dichloroethylene were detected in the effluent at an average of 0.12 mg L−1, 3.9 mg L−1, and 1.9 mg L−1, respectively. The total mass of chlorinated ethenes in the water was reduced by 99%. Over 95% of the recovered chlorine was as fre...

  20. Polyacrylonitrile/carbon nanotube composite fibers: Reinforcement efficiency and carbonization studies

    Science.gov (United States)

    Chae, Han Gi

    Polyacrylonitrile (PAN)/carbon nanotube (CNT) composite fibers were made using various processing methods such as conventional solution spinning, gel spinning, and bi-component gel spinning. The detailed characterization exhibited that the smaller and longer CNT will reinforce polymer matrix mostly in tensile strength and modulus, respectively. Gel spinning combined with CNT also showed the promising potential of PAN/CNT composite fiber as precursor fiber of the next generation carbon fiber. High resolution transmission electron microscopy showed the highly ordered PAN crystal layer on the CNT, which attributed to the enhanced physical properties. The subsequent carbonization study revealed that carbonized PAN/CNT fibers have at least 50% higher tensile strength and modulus as compared to those of carbonized PAN fibers. Electrical conductivity of CNT containing carbon fiber was also 50% higher than that of carbonized PAN fiber. In order to have carbon fiber with high tensile strength, the smaller diameter precursor fiber is preferable. Bi-component gel spinning produced 1-2 mum precursor fiber, resulting in ˜1 mum carbon fiber. The tensile strength of the carbonized bi-component fiber (islands fibers) is as high as 6 GPa with tensile modulus of ˜500 GPa. Further processing optimization may lead to the next generation carbon fiber.

  1. Study on the Balance of Agricultural Water and Land Resources on Ningxia Plain

    Institute of Scientific and Technical Information of China (English)

    Zhang Jing; Feng Zhiming; Yang Yanzhao

    2006-01-01

    The article puts forward the process and means of regional water and land balance research, and then from two scenarios which are the balances under natural regulation and human intervention, calculated and analysed the balance between water and land on Ningxia Plain. For the balance under natural regulation named farmland water balance, using farmland water resource balance equation, the research estimated the monthly farmland water balance of 8 major crops for all of the 12 counties on Ningxia Plain in the period of 1960-2001; for the balance under human intervention,the research estimated land-use water balance equation of the counties in 2000, and calculated the balance between land use and water resources including irrigating water of all the 12 counties on Ningxia Plain. Results showed that ①precipitation can not meet the water demand of the crops for growth and development on Ningxia Plain, and water shortage is the primary character of farmland water balance under natural regulation. ②the diversity of water and land balance of different counties is distinctly influenced by the crop structure, water quantity for irrigation and irrigation level. ③Irrigation water could meet the crop water demand on Ningxia Plain in 2000,but there was not much space to expand irrigating cultivated land.

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

    OpenAIRE

    Abir U Igamberdiev; Eprintsev, Alexander T.

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (c...

  3. HERschel Observations of Edge-on Spirals (HEROES). III. Dust energy balance study of IC 2531

    Science.gov (United States)

    Mosenkov, Aleksandr V.; Allaert, Flor; Baes, Maarten; Bianchi, Simone; Camps, Peter; De Geyter, Gert; De Looze, Ilse; Fritz, Jacopo; Gentile, Gianfranco; Hughes, Thomas M.; Lewis, Fraser; Verstappen, Joris; Verstocken, Sam; Viaene, Sébastien

    2016-07-01

    We investigate the dust energy balance for the edge-on galaxy IC 2531, one of the seven galaxies in the HEROES sample. We perform a state-of-the-art radiative transfer modelling based, for the first time, on a set of optical and near-infrared galaxy images. We show that by taking into account near-infrared imaging in the modelling significantly improves the constraints on the retrieved parameters of the dust content. We confirm the result from previous studies that including a young stellar population in the modelling is important to explain the observed stellar energy distribution. However, the discrepancy between the observed and modelled thermal emission at far-infrared wavelengths, the so-called dust energy balance problem, is still present: the model underestimates the observed fluxes by a factor of about two. We compare two different dust models, and find that dust parameters, and thus the spectral energy distribution in the infrared domain, are sensitive to the adopted dust model. In general, the THEMIS model reproduces the observed emission in the infrared wavelength domain better than the popular BARE-GR-S model. Our study of IC 2531 is a pilot case for detailed and uniform radiative transfer modelling of the entire HEROES sample, which will shed more light on the strength and origins of the dust energy balance problem. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.The reduced images (as FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A71

  4. Effects of Sigma Anti-bonding Molecule Calcium Carbonate on bone turnover and calcium balance in ovariectomized rats.

    Science.gov (United States)

    Choi, So-Young; Park, Dongsun; Yang, Goeun; Lee, Sun Hee; Bae, Dae Kwon; Hwang, Seock-Yeon; Lee, Paul K; Kim, Yun-Bae; Kim, Ill-Hwa; Kang, Hyun-Gu

    2011-12-01

    This study was conducted to evaluate the effect of Sigma Anti-bonding Molecule Calcium Carbonate (SAC) as therapy for ovariectomy-induced osteoporosis in rats. Three weeks after surgery, fifteen ovariectomized Sprague-Dawley rats were divided randomly into 3 groups: sham-operated group (sham), ovariectomized group (OVX) and SAC-treatment group (OVX+SAC). The OVX+SAC group was given drinking water containing 0.0012% SAC for 12 weeks. Bone breaking force and mineralization as well as blood parameters related to the bone metabolism were analyzed. In OVX animals, blood concentration of 17β-estradiol decreased significantly, while osteocalcin and type I collagen C-terminal telopeptides (CTx) increased. Breaking force, bone mineral density (BMD), calcium and phosphorus in femurs, as well as uterine and vaginal weights, decreased significantly following OVX. However, SAC treatment (0.0012% in drinking water) not only remarkably restored the decreased 17β-estradiol and increased osteocalcin and CTx concentrations, but also recovered decreased femoral breaking force, BMD, calcium and phosphorus, although it did not reversed reproductive organ weights. It is suggested that SAC effectively improve bone density by preventing bone turnover mediated osteocalcin, CTx and minerals, and that it could be a potential candidate for therapy or prevention of postmenopausal osteoporosis.

  5. Adapting fire management to future fire regimes: impacts on boreal forest composition and carbon balance in Canadian National Parks

    Science.gov (United States)

    de Groot, W. J.; Flannigan, M. D.; Cantin, A.

    2009-04-01

    The effects of future fire regimes altered by climate change, and fire management in adaptation to climate change were studied in the boreal forest region of western Canada. Present (1975-90) and future (2080-2100) fire regimes were simulated for several National Parks using data from the Canadian (CGCM1) and Hadley (HadCM3) Global Climate Models (GCM) in separate simulation scenarios. The long-term effects of the different fire regimes on forests were simulated using a stand-level, boreal fire effects model (BORFIRE). Changes in forest composition and biomass storage due to future altered fire regimes were determined by comparing current and future simulation results. This was used to assess the ecological impact of altered fire regimes on boreal forests, and the future role of these forests as carbon sinks or sources. Additional future simulations were run using adapted fire management strategies, including increased fire suppression and the use of prescribed fire to meet fire cycle objectives. Future forest composition, carbon storage and emissions under current and adapted fire management strategies were also compared to determine the impact of various future fire management options. Both of the GCM's showed more severe burning conditions under future fire regimes. This includes fires with higher intensity, greater depth of burn, greater total fuel consumption and shorter fire cycles (or higher rates of annual area burned). The Canadian GCM indicated burning conditions more severe than the Hadley GCM. Shorter fire cycles of future fire regimes generally favoured aspen, birch, and jack pine because it provided more frequent regeneration opportunity for these pioneer species. Black spruce was only minimally influenced by future fire regimes, although white spruce declined sharply. Maintaining representation of pure and mixed white spruce ecosystems in natural areas will be a concern under future fire regimes. Active fire suppression is required in these areas. In

  6. Carbon balance and crop residue management in dynamic equilibrium under a no-till system in Campos Gerais

    Directory of Open Access Journals (Sweden)

    Ademir de Oliveira Ferreira

    2012-11-01

    Full Text Available The adoption of no-tillage systems (NT and the maintenance of crop residues on the soil surface result in the long-term increase of carbon (C in the system, promoting C sequestration and reducing C-CO2 emissions to the atmosphere. The purpose of this study was to evaluate the C sequestration rate and the minimum amount of crop residues required to maintain the dynamic C equilibrium (dC/dt = 0 of two soils (Typic Hapludox with different textural classes. The experiment was arranged in a 2 x 2 x 2 randomized block factorial design. The following factors were analyzed: (a two soil types: Typic Hapludox (Oxisol with medium texture (LVTM and Oxisol with clay texture (LVTA, (b two sampling layers (0-5 and 5-20 cm, and (c two sampling periods (P1 - October 2007; P2 - September 2008. Samples were collected from fields under a long-term (20 years NT system with the following crop rotations: wheat/soybean/black oat + vetch/maize (LVTM and wheat/maize/black oat + vetch/soybean (LVTA. The annual C sequestration rates were 0.83 and 0.76 Mg ha-1 for LVTM and LVTA, respectively. The estimates of the minimum amount of crop residues required to maintain a dynamic equilibrium (dC/dt = 0 were 7.13 and 6.53 Mg ha-1 year-1 for LVTM and LVTA, respectively. The C conversion rate in both studied soils was lower than that reported in other studies in the region, resulting in a greater amount of crop residues left on the soil surface.

  7. [Global climate change and carbon balance in forest ecosystems of boreal zones: imitating modeling as a forecast tool].

    Science.gov (United States)

    Shanin, V N; Mikhaĭlov, A V; Bykhovets, S S; Komarov, A S

    2010-01-01

    The individually oriented system of the EFIMOD models simulating carbon and nitrogen flows in forest ecosystems has been used for forecasting the response of forest ecosystems to various forest exploitation regimes with climate change. As input data the forest management materials for the Manturovskii forestry of the Kostroma region were used. It has been shown that increase of mid-annual temperatures and rainfall influence the redistribution of carbon and nitrogen supply in organic form: supply increase of these elements in phytomass simultaneously with depletion of them in soil occurred. The most carbon and nitrogen accumulation in forest ecosystems occurs in the scenario without felling. In addition, in this scenario only the ecosystems of the modeling territory function as a carbon drain; in the other two scenarios (with selective and total felling) they function as a source of carbon. Climate changes greatly influence the decomposition rate of organic matter in soil, which leads to increased emission of carbonic acid. The second consequence of the increase in the destruction rate is nitrogen increase in the soil in a form available for plants that entails production increase of plantations. PMID:21268870

  8. The impacts of drainage, nutrient status and management practice on the full carbon balance of grasslands on organic soils in a maritime temperate zone

    Science.gov (United States)

    Renou-Wilson, F.; Barry, C.; Müller, C.; Wilson, D.

    2014-08-01

    Temperate grasslands on organic soils are diverse due to edaphic properties but also to regional management practices and this heterogeneity is reflected in the wide range of greenhouse gas (GHG) flux values reported in the literature. In Ireland, most grasslands on organic soils were drained several decades ago and are managed as extensive pastures with little or no fertilisation. This study describes a 2-year study of the net ecosystem carbon balance (NECB) of two such sites. We determined GHG fluxes and waterborne carbon (C) emissions in a nutrient-rich grassland and compared it with values measured from two nutrient-poor organic soils: a deep-drained and a shallow-drained site. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were determined using the chamber technique, and fluvial C fluxes were estimated by combining drainage water concentrations and flows. The nutrient-rich site was an annual source of CO2 (233 g C m-2 yr-1), CH4 neutral, and a small source of N2O (0.16 g N2O-N m-2 yr-1). Net ecosystem exchange (NEE) at the shallow-drained nutrient-poor site was -89 and -99 g C m-2 yr-1 in Years 1 and 2 respectively, and NEE at the deep-drained nutrient-poor site was 85 and -26 g C m-2 yr-1 respectively. Low CH4 emissions (1.3 g C m-2 yr-1) were recorded at the shallow-drained nutrient-poor site. Fluvial exports from the nutrient-rich site totalled 69.8 g C m-2 yr-1 with 54% as dissolved organic C. Waterborne C losses from the nutrient-poor site reflected differences in annual runoff totalling 44 g C m-2 yr-1 in Year 1 and 30.8 g C m-2 yr-1 in Year 2. The NECB of the nutrient-rich grassland was 663 g C m-2 yr-1 with biomass exports being the major component accounting for 53%. The NECB of the nutrient-poor deep-drained site was less than half of the nutrient-rich site (2-year mean 267 g C m-2 yr-1). Although NEE at the nutrient-poor shallow-drained site was negative in both years, high biomass export meant it was a net C source (2-year mean

  9. Balance Problems

    Science.gov (United States)

    ... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady or as ... fall-related injuries, such as hip fracture. Some balance problems are due to problems in the inner ...

  10. Investigating the role of background and observation error correlations in improving a model forecast of forest carbon balance using four dimensional variational data assimilation.

    Science.gov (United States)

    Pinnington, Ewan; Casella, Eric; Dance, Sarah; Lawless, Amos; Morison, James; Nichols, Nancy; Wilkinson, Matthew; Quaife, Tristan

    2016-04-01

    Forest ecosystems play an important role in sequestering human emitted carbon-dioxide from the atmosphere and therefore greatly reduce the effect of anthropogenic induced climate change. For that reason understanding their response to climate change is of great importance. Efforts to implement variational data assimilation routines with functional ecology models and land surface models have been limited, with sequential and Markov chain Monte Carlo data assimilation methods being prevalent. When data assimilation has been used with models of carbon balance, background "prior" errors and observation errors have largely been treated as independent and uncorrelated. Correlations between background errors have long been known to be a key aspect of data assimilation in numerical weather prediction. More recently, it has been shown that accounting for correlated observation errors in the assimilation algorithm can considerably improve data assimilation results and forecasts. In this paper we implement a 4D-Var scheme with a simple model of forest carbon balance, for joint parameter and state estimation and assimilate daily observations of Net Ecosystem CO2 Exchange (NEE) taken at the Alice Holt forest CO2 flux site in Hampshire, UK. We then investigate the effect of specifying correlations between parameter and state variables in background error statistics and the effect of specifying correlations in time between observation error statistics. The idea of including these correlations in time is new and has not been previously explored in carbon balance model data assimilation. In data assimilation, background and observation error statistics are often described by the background error covariance matrix and the observation error covariance matrix. We outline novel methods for creating correlated versions of these matrices, using a set of previously postulated dynamical constraints to include correlations in the background error statistics and a Gaussian correlation

  11. Constrained Allocation Flux Balance Analysis

    CERN Document Server

    Mori, Matteo; Martin, Olivier C; De Martino, Andrea; Marinari, Enzo

    2016-01-01

    New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an "ensemble averaging" procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferr...

  12. Comparison of balance assessment modalities in emergency department elders: a pilot cross-sectional observational study

    Directory of Open Access Journals (Sweden)

    Karaman Rowan

    2009-09-01

    Full Text Available Abstract Background More than one-third of US adults 65 and over fall every year. These falls may cause serious injury including substantial long-term morbidity (due declines in activities of daily living and death. The emergency department (ED visit represents an opportunity for identifying high risk elders and potentially instituting falls-related interventions. The unique characteristic of the ED environment and patient population necessitate that risk-assessment modalities be validated in this specific setting. In order to better identify elders at risk of falls, we examined the relationship between patient-provided history of falling and two testing modalities (a balance plate system and the timed up-and-go [TUG] test in elder emergency department (ED patients. Methods We conducted a cross-sectional observational study of patients ≥ 60 years old being discharged from the ED. Patient history of falls in the past week, month, 6 months, and year was obtained. Balance plate center of pressure excursion (COP measurements and TUG testing times were recorded. COP was recorded under four conditions: normal stability eyes open (NSEO and closed (NSEC, and perturbed stability eyes open and closed. Correlation between TUG and COP scores was measured. Univariate logistic regression was used to identify the relationship between patient-provided falls history and the two testing modalities. Proportions, likelihood ratios, and receiver-operating-characteristic (ROC curves for prediction of previous falls were reported. Results Fifty-three subjects were enrolled, 11% had fallen in the previous week and 42% in the previous year. There was no correlation between TUG and any balance plate measurements. In logistic regression, neither testing modality was associated with prior history of falls (p > 0.05 for all time periods. Balance plate NSEO and NSEC testing cutoffs could be identified which were 83% sensitive and had a negative likelihood ratio (LR- of 0

  13. A mass balance study on nitrification and deammonification in vertical flow constructed wetlands treating landfill leachate.

    Science.gov (United States)

    Sun, G; Austin, D

    2007-01-01

    A laboratory-scale, mass-balance study was carried out on the transformation of nitrogenous pollutants in four vertical flow wetland columns. Landfill leachate containing low organic matter, but a high concentration of ammoniacal-nitrogen, was treated under dissolved oxygen concentrations close to saturation. Influent total nitrogen (TN) comprised ammoniacal-nitrogen with less than 1% nitrate and nitrite, negligible organic nitrogen, and very low BOD. Nitrification occurred in three of the four columns. There was a substantial loss of total nitrogen (52%) in one column, whereas other columns exhibited zero to minor losses (< 12%). Nitrogen loss under study conditions was unexpected. Two hypotheses are proposed to account for it: (1) either the loss of TN is attributed to nitrogen transformation into a form (provisionally termed alpha-nitrogen) that is undetectable by the analytical methods used; or (2) the loss is caused by microbial denitrification or deammonification. By elimination and stoichiometric mass balance calculations, completely autotrophic nitrogen-removal over nitrite (CANON) deammonification is confirmed as responsible for nitrogen loss in one column. This result reveals that CANON can be native to aerobic engineered wetland systems treating high ammonia, low organic content wastewater.

  14. Balance-of-plant outage availability study. Phase I. Extension report

    International Nuclear Information System (INIS)

    After completion of the Phase 1 Refueling Outage Availability Study, Babcock and Wilcox and the U.S. Department of Energy entered into a supplemental agreement to perform a balance-of-plant maintenance, inspection, and test study with the cooperation of Duke Power Company and Arkansas Power and Light Company. The objectives were (1) to expand the Phase 1 data base, including balance-of-plant activities, to reduce outage time and increase plant availability and (2) to conduct an onsite review of plant maintenance, practices to complement the utility efforts in reducing outage time and increasing on-line operational time. Data were obtained from (1) observations during the 1977 refueling outage at Oconee 3, (2) review of maintenance practices during the Arkansas Nuclear One, Unit 1, operational cycle in 1977, and (3) selected observations of the 1978 refueling outage at ANO-1. Accumulated data were then reviewed and analyzed to produce a list of improvement recommendations for Oconee 3 and ANO-1 that can be generically applied to plants of similar design and construction

  15. The association between fluid balance and mortality in patients with ARDS was modified by serum potassium levels: a retrospective study

    Directory of Open Access Journals (Sweden)

    Zhongheng Zhang

    2015-02-01

    Full Text Available Background and Objective. Acute respiratory distress syndrome (ARDS is characterized by pulmonary edema and may benefit from conservative fluid management. However, conflicting results exist in the literature. The study aimed to investigate the association between mean fluid balance and mortality outcome in ARDS patients who required invasive mechanical ventilation. Methods. The study was a secondary analysis of a prospectively collected dataset obtained from the NHLBI Biologic Specimen and Data Repository Information Coordinating Center. ARDS patients with invasive mechanical ventilation were eligible. Demographic and laboratory data were extracted from the dataset. Multivariable regression model was built by stepwise selection of covariates. A fractional polynomial approach was used to test the linearity of mean fluid balance in the model. The potential interactions of mean fluid balance with other variables were tested. Main Results. A total of 282 patients were eligible for the analysis, including 61 non-survivors with a mortality rate of 21.6%. After stepwise regression analysis, mean fluid balance remained to be an independent predictor of death (OR: 1.00057; 95% CI [1.00034–1.00080]. The two-term model obtained using fractional polynomial analysis was not superior to the linear model. There was significant interaction between mean fluid balance and serum potassium levels (p = 0.011. While the risk of death increased with increasing mean fluid balance at potassium levels of 1.9, 2.9 , 3.9 and 4.9 mmol/l, the risk decreased at potassium level of 5.9 mmol/l. Conclusion. The present study demonstrates that more positive fluid balance in the first 8 days is significantly associated with increased risk of death. However, the relationship between mean fluid balance and mortality can be modified by serum potassium levels. With hyperkalemia, more positive fluid balance is associated with reduced risk of death.

  16. Report on carbon and nitrogen abundance studies

    Science.gov (United States)

    Boehm-Vitense, Erika

    1991-01-01

    The aim of the proposal was to determine the nitrogen to carbon abundance ratios from transition layer lines in stars with different T(sub eff) and luminosities. The equations which give the surface emission line fluxes and the measured ratio of the NV to CIV emission line fluxes are presented and explained. The abundance results are compared with those of photospheric abundance studies for stars in common with the photospheric investigations. The results show that the analyses are at least as accurate as the photospheric determinations. These studies can be extended to F and early G stars for which photospheric abundance determinations for giants are hard to do because molecular bands become too weak. The abundance determination in the context of stellar evolution is addressed. The N/C abundance ratio increases steeply at the point of evolution for which the convection zone reaches deepest. Looking at the evolution of the rotation velocities v sin i, a steep decrease in v sin i is related to the increasing depth of the convection zone. It is concluded that the decrease in v sin i for T(sub eff) less than or approximately = 5800 K is most probably due to the rearrangement of the angular momentum in the stars due to deep convective mixing. It appears that the convection zone is rotating with nearly depth independent angular momentum. Other research results and ongoing projects are discussed.

  17. Significant contributions of fungal spores to the organic carbon and to the aerosol mass balance of the urban atmospheric aerosol

    Science.gov (United States)

    Bauer, Heidi; Schueller, Elisabeth; Weinke, Gert; Berger, Anna; Hitzenberger, Regina; Marr, Iain L.; Puxbaum, Hans

    Fungal spores are ubiquitous components of atmospheric aerosols and are therefore also contributors to the organic carbon (OC) component and to the mass of PM 10 (PM—particulate matter) aerosols. In this study we use spore counts and an experimentally derived factor of 13 pg C and of 33 pg fresh weight per spore for assessing quantitatively the contribution to OC and PM 10. The concentrations of airborne fungal spores were determined at a suburban (Schafberg) and a traffic-dominated urban site (Rinnböckstrasse) in Vienna, Austria, during spring and summer. Fungal spores OC ranged from 22 to 677 ng m -3 with a summer mean value of around 350 ng m -3 at the suburban site and 300 ng m -3 at the urban traffic site. At the suburban site fungal spores contributed on average 6% in spring and 14% in summer to aerosol OC mass concentration. At the traffic-dominated site fungal spores accounted for 2% of OC in spring and for 8% in summer. The fungal contribution to PM 10 was also notable and amounted to 3% and 7% at the suburban and to 1% and 4% at the urban site in spring and summer, respectively. Impactor measurements of OC at the suburban site showed that in summer fungal spores were predominant contributors to the coarse aerosol OC, and accounted on average for 60% of the OC in the PM 2-10 fraction. Fungal spores thus can be regarded as main components to PM 10, total OC and, most importantly, coarse OC even in urban areas.

  18. HERschel Observations of Edge-on Spirals (HEROES). III. Dust energy balance study of IC 2531

    CERN Document Server

    Mosenkov, Aleksandr V; Baes, Maarten; Bianchi, Simone; Camps, Peter; De Geyter, Gert; De Looze, Ilse; Fritz, Jacopo; Gentile, Gianfranco; Hughes, Thomas M; Lewis, Fraser; Verstappen, Joris; Verstocken, Sam; Viaene, Sébastien

    2016-01-01

    We investigate the dust energy balance for the edge-on galaxy IC 2531, one of the seven galaxies in the HEROES sample. We perform a state-of-the-art radiative transfer modelling based, for the first time, on a set of optical and near-infrared galaxy images. We show that taking into account near-infrared imaging in the modelling significantly improves the constraints on the retrieved parameters of the dust content. We confirm the result from previous studies that including a young stellar population in the modelling is important for explaining the observed stellar energy distribution. However, the discrepancy between the observed and modelled thermal emission at far-infrared wavelengths, the so-called dust energy balance problem, is still present: the model underestimates the observed fluxes by a factor of about two. We compare two different dust models, and find that dust parameters and thus the spectral energy distribution in the infrared domain are sensitive to the adopted dust model. In general, the THEMIS...

  19. Comparative study of niobium nitride coatings deposited by unbalanced and balanced magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Olaya, J.J. [Departamento de Ingenieria Mecanica y Mecatronica, Universidad Nacional de Colombia, Bogota Colombia (Colombia); Rodil, S.E. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Mexico D. F. 04510 (Mexico); Muhl, S. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Mexico D. F. 04510 (Mexico)], E-mail: muhl@servidor.unam.mx

    2008-10-01

    Niobium nitride (NbN) coatings have many interesting properties such as chemical inertness, excellent mechanical properties, high electrical conductivity, high melting point, and a superconducting transition temperature between 16 and 17 K. For this reason, these compounds have many potential thin film applications. In this work we compare the properties of NbN{sub x} films deposited using well-characterized balanced and unbalanced magnetron sputtering systems. Samples of NbN were deposited in the two systems under almost identical deposition conditions, that is, the same substrate temperature, plasma power, gas pressure, substrate to target distance and Ar/N{sub 2} ratio. Prior to the film preparation both the magnetic field geometry and the characteristics of the plasma were determined. The microstructure and composition of the deposits were analyzed by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The corrosion resistance and the micro-abrasion wear resistance were measured by anodic polarization potentiodynamic studies and by ball cratering, respectively. The NbN films grown using the highly unbalanced magnetron configuration had a preferential (111) crystal orientation and a composite hardness of up to 2400 HV{sub 0.025}. While the films deposited using the balanced magnetron had a mixed crystalline orientation and a hardness of 2000 HV{sub 0.025}. The results demonstrate the strong effect of magnetic field configuration on the ion bombardment, and the resultant coating characteristics.

  20. A mass balance study of the phytoremediation of perchloroethylene-contaminated groundwater

    International Nuclear Information System (INIS)

    A mass balance study was performed under controlled field conditions to investigate the phytoremediation of perchloroethylene (PCE) by hybrid poplar trees. Water containing 7-14 mg L-1 PCE was added to the test bed. Perchloroethylene, trichloroethylene, and cis-dichloroethylene were detected in the effluent at an average of 0.12 mg L-1, 3.9 mg L-1, and 1.9 mg L-1, respectively. The total mass of chlorinated ethenes in the water was reduced by 99%. Over 95% of the recovered chlorine was as free chloride in the soil, indicating near-complete dehalogenation of the PCE. Transpiration, volatilization, and accumulation in the trees were all found to be minor loss mechanisms. In contrast, 98% of PCE applied to an unplanted soil chamber was recovered as PCE in the effluent water or volatilized into the air. These results suggest that phytoremediation can be an effective method for treating PCE-contaminated groundwater in field applications. - A chlorine balance performed on a planted test bed with PCE-contaminated water demonstrated VOC mass reduction of 99% and complete dechlorination.

  1. Study on the application of active balancing device to solve the vibration problem for the rotor with bending fault

    Institute of Scientific and Technical Information of China (English)

    He Lidong; Shen Wei; Gao Jinji; Zhou Weihua

    2006-01-01

    The rotor with bending faults that occurrs on the rotating machinery usually vibrates seriously. This paper investigates to apply the active balancing device on a flexible rotor with bending faults to solve the vibration problem. Two problems are studied by finite element method firstly: Where the balance actuator is fixed on the shaft and how much the balancing capacity of the active balancing device is needed. The experiment is then carried out on the test rig, which consists of a flexible rotor with bending faults. The test results indicate that the bending rotor peak vibration response can be decreased from 550μm to 40μm below by using the active balancing device. The peak vibration response decreases approximately by 93%. The synchronous vibration due to the rotor bending faults can be controlled effectively by using active balancing device. The active balancing device is especially adapted to solve the problem caused by thermal distortion with time-variation and randomness, which is varied with working conditions, thus it has good practical value in practice.

  2. Water balance and carbon sink strength of an European savannah-type woodland during the drought year 2012

    Science.gov (United States)

    Piayda, A.; Dubbert, M.; Rebmann, C.; Kolle, O.; Costa e Silva, F.; Correia, A.; Pereira, J. S.; Werner, C.; Cuntz, M.

    2013-12-01

    Savannah-type ecosystems account for around 30% of global gross primary production (GPP) and are the second most important biome in terms of global GPP after the tropical forests. A typical savannah-type woodland in Europe (montado) consists of a sparse tree layer and a herbaceous understorey layer, covering an area of 2-2.5 million ha on the Iberian Peninsula. These ecosystems are adapted to regular summer droughts depending on life form (Chamaephyte or Therophyte) and access to different water reservoirs. In the recent past, annual precipitation exhibits a significant decrease in winter and spring as well as of total annual rainfall on the Iberian Peninsula. The objective of this study is to investigate the differences in ecosystem fluxes of a typical European savannah-type cork oak (Quercus suber L.) woodland between the very wet year 2011 and the extreme drought year 2012. We measured CO2 and H2O fluxes of the trees and the understory with two eddy covariance towers above and below the tree canopy, respectively. We also measured auxiliary ecosystem variables such as precipitation, soil temperature Ts and moisture θ, and leaf area index LAI. Precipitation P was 34% higher in 2011 and 39% lower in 2012 than the long-term average. The intra-annual pattern of P shows a severe drought anomaly in winter to early spring 2012 accounting for up to 68% of the total annual P reduction. However, evapotranspiration (ET) only diminished by 15% due to a decrease in canopy conductance gc while vapour pressure deficit stayed almost constant. Thus, annual ET/P fraction increased from 34% to 80%. This left only a very small amount of water for soil moisture replenishing, resulting in only half the soil moisture in spring 2012 compared to the spring 2011. While gc was reduced by 15% in 2012 compared to 2011, annual GPP of the trees was reduced by 28%. We could attribute this by fitting the Farquhar-model of photosynthesis to a further reduction of the maximum carboxylation rate

  3. Feasibility study of tar sands conditioning for earth pressure balance tunnelling

    Directory of Open Access Journals (Sweden)

    D. Martinelli

    2015-12-01

    Full Text Available This paper presents the results of laboratory test on the feasibility of soil conditioning for earth pressure balance (EPB excavation in a tar sand, which is a natural material never studied in this respect. The laboratory test performed is based on a procedure and methods used in previous studies with different types of soils, but for this special complex material, additional tests are also conducted to verify particular properties of the tar sands, such as the tilt test and vane shear test usually used in cohesive materials, and a direct shear test. The laboratory test proves that the test procedure is applicable also to this type of soil and the conditioned material can be considered suitable for EPB excavations, although it is necessary to use a certain percentage of fine elements (filler to create a material suitable to be mixed with foam. The test results show that the conditioned material fulfils the required standard for an EPB application.

  4. AN EXPLORATORY STUDY ON THE WORK-LIFE BALANCE OF WOMEN ENTREPRENEURS IN SOUTH INDIA

    Directory of Open Access Journals (Sweden)

    N. Panchanatham

    2011-07-01

    Full Text Available In India, entrepreneurship has traditionally been considered a male prerogative. However, in tandem with a changing socio-cultural environment and an increase in educational opportunities, women have started recognising their inherent talents and business skills. With the help of various governmental and non-governmental agencies, growing numbers of women are joining the ranks of entrepreneurs. However, in the existing familial and societal setup, entrepreneurial women are overburdened and find it increasingly difficult to balance their work and life roles. Therefore, the major objective of the present study was to develop and validate an appropriate tool to illustrate the work-life balance (WLB issues faced by women entrepreneurs of South India. We also sought to understand the important factors influencing the WLB of these women entrepreneurs. To achieve this end, data were collected by area sampling (cluster- random paired with semi-structured interviews and a questionnaire. The generated data were subjected to standard statistical procedures, such as factor analysis, regression analysis, analysis of variance (ANOVA and student's t-test. The five-point psychometric tool developed consisted of 39 statements related to five factors. Each of the statements possessed adequate reliability and validity. This study revealed that role overload, dependent care issues, quality of health, problems in time management and lack of proper social support are the major factors influencing the WLB of women entrepreneurs in India. Furthermore, even though the vast majority of the entrepreneurs examined in this study suffers from WLB issues, there are significant differences in the level of WLB issues faced by the various categories of women entrepreneurs. The present study provides recommendations for human resource professionals, management consultants, academicians and women entrepreneurs themselves to deal with the major WLB issues faced by Indian women

  5. Source identification and mass balance studies of mercury in Lake An-dong, S. Korea

    Science.gov (United States)

    Han, J.; Byeon, M.; Yoon, J.; Park, J.; Lee, M.; Huh, I.; Na, E.; Chung, D.; Shin, S.; Kim, Y.

    2009-12-01

    In this study, mercury and methylmercury were measured in atmospheric, tributary, open-lake water column, sediment, planktons and fish samples in the catchments area of Lake An-dong, S. Korea. Lake An-dong, an artificial freshwater lake is located on the upstream of River Nak-dong. It has 51.5 km2 of open surface water and 1.33 year of hydraulic residence time. It is a source of drinking water for 0.3 million S. Koreans. Recently, the possibilities of its mercury contamination became an issue since current studies showed that the lake had much higher mercury level in sediment and certain freshwater fish species than any other lakes in S. Korea. This catchments area has the possibilities of historical mercury pollution by the location of more than 50 abandoned gold mines and Young-poong zinc smelter. The objective of this study was to develop a mercury mass balance and identify possible mercury sources in the lake. The results of this study are thus expected to offer valuable insights for the sources of mercury loading through the watershed. In order to estimate the mercury flux, TGM, RGM and particulate mercury were measured using TEKRAN 2537 at the five sites surrounding Lake An-dong from May, 2009 with wet and dry deposition. The fate and transport of mercury in water body were predicted by using EFDC (Environmental Dynamic Fluid Code) and Mercury module in WASP7 (Water quality analysis program) after subsequent distribution into water body, sediments, followed by bioaccumulation and ultimate uptake by humans. The mercury mass balance in Young-poong zinc smelter was also pre-estimated by measuring mercury content in zinc ores, emission gases, sludge, wastewater and products.

  6. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity.

    Science.gov (United States)

    Li, Xi; Toma, Yo; Yeluripati, Jagadeesh; Iwasaki, Shinya; Bellingrath-Kimura, Sonoko D; Jones, Edward O; Hatano, Ryusuke

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959-2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from -1.26MgCha(-1)yr(-1) in 1959-0.26 Mg Cha(-1)yr(-1) in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959-2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. PMID:26956176

  7. Acción colectiva y subjetividad: Un balance desde los estudios sociales Collective action and subjetivity: a balance from social studies

    Directory of Open Access Journals (Sweden)

    Alfonso Torres Carrillo

    2009-12-01

    Full Text Available Los movimientos sociales han sido constitutivos de las sociedades y de las ciencias sociales contemporáneas; tanto que hoy constituyen uno de los campos de investigación más prolíficos de los estudios sociales. El artículo hace una revisión crítica del lugar que han tenido las dimensiones subjetivas de la acción colectiva, entre los diferentes enfoques teóricos sobre los movimientos sociales. Además, presenta y documenta la emergencia de la subjetividad como campo problemático y perspectiva interpretativa en los estudios sociales contemporáneos. A partir de este balance, se plantea un modelo analítico para abordar procesos organizativos y de movilización social en contextos urbanos, destacando el peso de aspectos subjetivos presentes en ellos.Social movements have contributed to shape societies and contemporary Social Sciences, so much that this topic constitutes one of the more prolific fields of research in Social Studies. This article provides a critical review of the place that the dimensions of collective action have had within the different theoretical perspectives about social movements. In addition, this paper presents and documents the emergence of subjectivity as a problematic field of interpretation in contemporary social studies. From this balance, an analytical model is proposed to address organizational processes and social mobilization in urban settings, emphasizing the relevance of subjective aspects in them.

  8. Impacts of partial harvesting on the carbon and water balance of a mixed conifer forest attacked by the mountain pine beetle

    Science.gov (United States)

    Mathys, A.; Black, T. A.; Brown, M.; Nesic, Z.; Nishio, G.; Burton, P.; Spittlehouse, D.; Fredeen, A.; Trofymow, T.; Grant, N.; Lessard, D.; Bowler, R.

    2011-12-01

    The mountain pine beetle (MPB) outbreak has had a major impact on the carbon (C) and water balances of forests in Interior BC, Canada. As a management response, the forest sector has increased the annual allowable cut to enable partial harvesting in the timber supply areas. Protecting the non-pine secondary structure provides opportunities for mid-term (15-30 years) timber harvest, while providing habitat for wildlife, reducing run-off to rivers and streams and retaining stand biomass. This study investigates the effects of partial cutting on the CO2 and H2O fluxes and also compares it to clearcut harvesting. The study area is an MPB-attacked forest located near Summit Lake (54°13'N, 122°37'W) about 40 km north of Prince George, BC. In February and March 2009, the beetle-killed lodgepole pine trees (Pinus contorta var. latifolia) were removed, leaving 49% of secondary structure consisting mainly of black spruce (Picea mariana), white hybrid spruce (Picea engelmannii x glauca) and subalpine fir trees (Abies lasiocarpa) with a canopy height of ~16 m and a stand density of 535 stems ha-1. Net ecosystem productivity (NEP) has been continuously measured since October 2009 with the eddy-covariance technique using an ultrasonic anemometer and an open-path infrared gas analyzer mounted 26 m above the ground. This poster reports results for 2010, which was a relatively normal year in central BC with respect to solar radiation, precipitation and air temperature. During the growing season the stand was a C sink, with monthly total NEP values of up to 23.1 g C m-2 in June. Midday evapotranspiration rates did not exceed 0.3 mm h-1 with Bowen ratios usually greater than 1.5. By the end of the year the stand was a weak C source with an annual NEP of -50 g C m-2. In comparison, clearcuts in the region remain C sources for many years during the growing season. Results for 2011 will also be presented and compared to flux measurements in part of the stand that was clearcut

  9. Fertilizer 15N balance in a coffee cropping system: a case study in Brazil

    International Nuclear Information System (INIS)

    Knowledge about the fate of fertilizer nitrogen in agricultural systems is essential for the improvement of management practices in order to maximize nitrogen (N) recovery by the crop and reduce N losses from the system to a minimum. This study involves fertilizer management practices using the 15N isotope label applied in a single rate to determine the fertilizer-N balance in a particular soil-coffee-atmosphere system and to deepen the understanding of N plant dynamics. Five replicates consisting of plots of about 120 plants each were randomly defined within a 0.2 ha coffee plantation planted in 2001, in Piracicaba, SP, Brazil. Nine plants of each plot were separated in sub-plots for the 15N balance studies and treated with N rates of 280 and 350 kg ha-1 during 2003/2004 and 2004/ 2005, respectively, both of them as ammonium sulfate enriched to a 15N abundance of 2.072 atom %. Plant shoots were considered as separate parts: the orthotropic central branch, productive branches, leaves of productive branches, vegetative branches, leaves of vegetative branches and fruit. Litter, consisting of dead leaves accumulated below the plant canopy, was measured by the difference between leaves at harvest and at the beginning of the following flowering. Roots and soil were sampled down to a depth of 1.0 at intervals of 0.2 m. Samples from the isotopic sub-plots were used to evaluate total N and 15N, and plants outside sub-plots were used to evaluate dry matter. Volatilization losses of NH3 were estimated using special collectors. Leaching of fertilizer-N was estimated from deep drainage water fluxes and 15N concentrations of the soil solution at 1 m soil depth. At the end of the 2-year evaluation, the recovery of 15N applied as ammonium sulfate was 19.1 % in aerial plant parts, 9.4 % in the roots, 23.8 % in the litter, 26.3 % in the fruit and 12.6 % remaining in the 0-1.0 m soil profile. Annual leaching and volatilization losses were very small (2.0 % and 0.9 %, respectively

  10. Fertilizer {sup 15}N balance in a coffee cropping system: a case study in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Fenilli, Tatiele Anete Bergamo [Universidade Regional de Blumenau (URB), SC (Brazil). Dept. de Engenharia Florestal]. E-mail: tfenilli@furb.br; Reichardt, Klaus; Bacchi, Osny Oliveira Santos [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil). Lab. de Fisica do Solo]. E-mails: klaus@cena.usp.br; osny@cena.usp.br; Favarin, Jose Laercio [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Producao Vegetal; Silva, Adriana Lucia [Centro de Tecnologia Canavieira (CTC), Piracicaba, SP (Brazil). Fazenda Santo Antonio]. E-mail: adriana.silva@ctc.com.br; Timm, Luis Carlos [Universidade Federal de Pelotas (UFPel), RS (Brazil). Dept. de Engenharia Rural]. E-mail: lcartimm@yahoo.com.br

    2008-07-15

    Knowledge about the fate of fertilizer nitrogen in agricultural systems is essential for the improvement of management practices in order to maximize nitrogen (N) recovery by the crop and reduce N losses from the system to a minimum. This study involves fertilizer management practices using the {sup 15}N isotope label applied in a single rate to determine the fertilizer-N balance in a particular soil-coffee-atmosphere system and to deepen the understanding of N plant dynamics. Five replicates consisting of plots of about 120 plants each were randomly defined within a 0.2 ha coffee plantation planted in 2001, in Piracicaba, SP, Brazil. Nine plants of each plot were separated in sub-plots for the {sup 15}N balance studies and treated with N rates of 280 and 350 kg ha-1 during 2003/2004 and 2004/ 2005, respectively, both of them as ammonium sulfate enriched to a {sup 15}N abundance of 2.072 atom %. Plant shoots were considered as separate parts: the orthotropic central branch, productive branches, leaves of productive branches, vegetative branches, leaves of vegetative branches and fruit. Litter, consisting of dead leaves accumulated below the plant canopy, was measured by the difference between leaves at harvest and at the beginning of the following flowering. Roots and soil were sampled down to a depth of 1.0 at intervals of 0.2 m. Samples from the isotopic sub-plots were used to evaluate total N and {sup 15}N, and plants outside sub-plots were used to evaluate dry matter. Volatilization losses of NH{sub 3} were estimated using special collectors. Leaching of fertilizer-N was estimated from deep drainage water fluxes and {sup 15}N concentrations of the soil solution at 1 m soil depth. At the end of the 2-year evaluation, the recovery of {sup 15}N applied as ammonium sulfate was 19.1 % in aerial plant parts, 9.4 % in the roots, 23.8 % in the litter, 26.3 % in the fruit and 12.6 % remaining in the 0-1.0 m soil profile. Annual leaching and volatilization losses were

  11. The OSU1/QUA2/TSD2-encoded putative methyltransferase is a critical modulator of carbon and nitrogen nutrient balance response in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Peng Gao

    Full Text Available The balance between carbon (C and nitrogen (N nutrients must be tightly coordinated so that cells can optimize their opportunity for metabolism, growth and development. However, the C and N nutrient balance perception and signaling mechanism remains poorly understood. Here, we report the isolation and characterization of two allelic oversensitive to sugar 1 mutants (osu1-1, osu1-2 in Arabidopsis thaliana. Using the cotyledon anthocyanin accumulation and root growth inhibition assays, we show that the osu1 mutants are more sensitive than wild-type to both of the imbalanced C/N conditions, high C/low N and low C/high N. However, under the balanced C/N conditions (low C/low N or high C/high N, the osu1 mutants have similar anthocyanin levels and root lengths as wild-type. Consistently, the genes encoding two MYB transcription factors (MYB75 and MYB90 and an Asn synthetase isoform (ASN1 are strongly up-regulated by the OSU1 mutation in response to high C/low N and low C/high N, respectively. Furthermore, the enhanced sensitivity of osu1-1 to high C/low N with respect to anthocyanin accumulation but not root growth inhibition can be suppressed by co-suppression of MYB75, indicating that MYB75 acts downstream of OSU1 in the high C/low N imbalance response. Map-based cloning reveals that OSU1 encodes a member of a large family of putative methyltransferases and is allelic to the recently reported QUA2/TSD2 locus identified in genetic screens for cell-adhesion-defective mutants. Accumulation of OSU1/QUA2/TSD2 transcript was not regulated by C and N balance, but the OSU1 promoter was slightly more active in the vascular system. Taken together, our results show that the OSU1/QUA2/TSD2-encoded putative methyltransferase is required for normal C/N nutrient balance response in plants.

  12. A Flexible Hybrid Model of Life Cycle Carbon Balance for Loblolly Pine (Pinus taeda L. Management Systems

    Directory of Open Access Journals (Sweden)

    Carlos A. Gonzalez-Benecke

    2011-09-01

    Full Text Available In this study we analyzed the effects of silvicultural treatments on carbon (C budgets in Pinus taeda L. (loblolly pine plantations in the southeastern United States. We developed a hybrid model that integrated a widely used growth and yield model for loblolly pine with published allometric and biometric equations to simulate in situ C pools. The model used current values of forest product conversion efficiencies and forest product decay rates to calculate ex situ C pools. Using the model to evaluate the effects of silvicultural management systems on C sequestration over a 200 year simulation period, we concluded that site productivity (site quality, which can be altered by silviculture and genetic improvement, was the major factor controlling stand C density. On low productivity sites, average net C stocks were about 35% lower than in stands with the default average site quality; in contrast, on high quality sites, C stocks were about 38% greater than average productivity stands. If woody products were incorporated into the accounting, thinning was C positive because of the larger positive effects on ex situ C storage, rather than smaller reductions on in situ C storage. The use of biological rotation age (18 years was not suitable for C sequestration, and extended rotation ages were found to increase stand C stock density. Stands with an 18-year-rotation length had 7% lower net C density than stands with a 22-year-rotation length; stands with a 35-year-rotation length had only 4% more C than stands harvested at age 22 years. The C sequestered in woody products was an important pool of C storage, accounting for ~34% of the average net C stock. Changes in decomposition rate, associated with possible environmental changes resulting from global climate change, affected C storage capacity of the forest. When decay rate was reduced to 10% or increased to 20%, the C stock in the dead pool (forest floor and coarse woody debris was reduced about 11

  13. The impacts of drainage, nutrient status and management practice on the full carbon balance of grasslands on organic soils in a maritime temperate zone

    Directory of Open Access Journals (Sweden)

    F. Renou-Wilson

    2014-04-01

    Full Text Available Temperate grasslands on organic soils are diverse due to edaphic properties but also to regional management practices and this heterogeneity is reflected in the wide range of greenhouse gas flux values reported in the literature. In Ireland, most grasslands on organic soils were drained several decades ago and are managed as extensive pastures with little or no fertilisation. This study describes a two-year study of the net ecosystem carbon balance (NECB of two such sites. We determined greenhouse gas (GHG fluxes and waterborne carbon emissions in a nutrient rich grassland and compared it with values measured from two nutrient poor organic soils: a deep drained and a shallow drained site. GHG fluxes (CO2, CH4 and N2O were determined using the chamber technique, and fluvial C fluxes were estimated by combining drainage water concentrations and flows. The nutrient rich site was an annual source of CO2 (NEE 233 g C m−2yr−1, CH4 neutral, and a small source of nitrous oxide (1.6 kg N2O-N ha−1yr−1. NEE at the shallow drained site was −89 and −99 g C m−2yr−1 in Years 1 and 2 respectively, and NEE at the deep drained site was +85 and −26 g C m−2yr−1 respectively. Low CH4 emissions (1.3 g C m−2yr−1 were recorded at the shallow drained nutrient poor site. Fluvial exports from the nutrient rich site totalled 69.8 g C m−2yr−1 with 54% as dissolved organic C (DOC. Waterborne C losses from the nutrient poor site reflected differences in annual runoff totalling 44 g C m−2yr−1 in Year 1 and 30.8 g C m−2yr−1 in Year 2. The NECB of the nutrient rich grassland was 663 g C m−2yr−1 with biomass exports being the major component accounting for 53%. The NECB of the nutrient poor deep drained site was less than half of the nutrient rich site (2 year mean 267 g C m−2yr−1. Although NEE at the nutrient poor shallow drained site was negative in both years, high biomass export meant it was a net C source (2 year mean NECB 103 g

  14. Differences in Energy Balance-Related Behaviours in European Preschool Children: The ToyBox-Study

    Science.gov (United States)

    De Craemer, Marieke; Lateva, Mina; Iotova, Violeta; De Decker, Ellen; Verloigne, Maïté; De Bourdeaudhuij, Ilse; Androutsos, Odysseas; Socha, Piotr; Kulaga, Zbigniew; Moreno, Luis; Koletzko, Berthold; Manios, Yannis; Cardon, Greet

    2015-01-01

    Background The aim of the current study was to compare levels of energy balance-related behaviours (physical activity, sedentary behaviour, and dietary behaviours (more specifically water consumption, sugar-sweetened beverage consumption and unhealthy snacking)) in four- to six-year-old preschoolers from six European countries (Belgium, Bulgaria, Germany, Greece, Poland, and Spain) within the ToyBox cross-sectional study. Methods A sample of 4,045 preschoolers (4.77 ± 0.43 years; 52.2% boys) had valid physical activity data (steps per day), parents of 8,117 preschoolers (4.78 ± 0.46 years; 53.0% boys) completed a parental questionnaire with questions on sedentary behaviours (television viewing, computer use, and quiet play), and parents of 7,244 preschoolers (4.77 ± 0.44 years; 52.0% boys) completed a food frequency questionnaire with questions on water consumption, sugar-sweetened beverage consumption and unhealthy snacking. Results The highest levels of physical activity were found in Spain (12,669 steps/day on weekdays), while the lowest levels were found in Bulgaria and Greece (9,777 and 9,656 steps/day on weekdays, respectively). German preschoolers spent the least amount of time in television viewing (43.3 min/day on weekdays), while Greek preschoolers spent the most time in television viewing (88.5 min/day on weekdays). A considerable amount of time was spent in quiet play in all countries, with the highest levels in Poland (104.9 min/day on weekdays), and the lowest levels in Spain (60.4 min/day on weekdays). Belgian, German, and Polish preschoolers had the lowest intakes of water and the highest intakes of sugar-sweetened beverages. The intake of snacks was the highest in Belgian preschoolers (73.1 g/day) and the lowest in Greek preschoolers (53.3 g/day). Conclusions Across six European countries, differences in preschoolers’ energy balance-related behaviours were found. Future interventions should target European preschoolers’ energy balance

  15. Differences in energy balance-related behaviours in European preschool children: the ToyBox-study.

    Directory of Open Access Journals (Sweden)

    Marieke De Craemer

    Full Text Available The aim of the current study was to compare levels of energy balance-related behaviours (physical activity, sedentary behaviour, and dietary behaviours (more specifically water consumption, sugar-sweetened beverage consumption and unhealthy snacking in four- to six-year-old preschoolers from six European countries (Belgium, Bulgaria, Germany, Greece, Poland, and Spain within the ToyBox cross-sectional study.A sample of 4,045 preschoolers (4.77 ± 0.43 years; 52.2% boys had valid physical activity data (steps per day, parents of 8,117 preschoolers (4.78 ± 0.46 years; 53.0% boys completed a parental questionnaire with questions on sedentary behaviours (television viewing, computer use, and quiet play, and parents of 7,244 preschoolers (4.77 ± 0.44 years; 52.0% boys completed a food frequency questionnaire with questions on water consumption, sugar-sweetened beverage consumption and unhealthy snacking.The highest levels of physical activity were found in Spain (12,669 steps/day on weekdays, while the lowest levels were found in Bulgaria and Greece (9,777 and 9,656 steps/day on weekdays, respectively. German preschoolers spent the least amount of time in television viewing (43.3 min/day on weekdays, while Greek preschoolers spent the most time in television viewing (88.5 min/day on weekdays. A considerable amount of time was spent in quiet play in all countries, with the highest levels in Poland (104.9 min/day on weekdays, and the lowest levels in Spain (60.4 min/day on weekdays. Belgian, German, and Polish preschoolers had the lowest intakes of water and the highest intakes of sugar-sweetened beverages. The intake of snacks was the highest in Belgian preschoolers (73.1 g/day and the lowest in Greek preschoolers (53.3 g/day.Across six European countries, differences in preschoolers' energy balance-related behaviours were found. Future interventions should target European preschoolers' energy balance-related behaviours simultaneously, but should

  16. TEM STUDY OF STRUCTURE OF GRAPHENE LAYERS IN SHUNGITE CARBON

    OpenAIRE

    KOVALEVSKI V.V.; MOSHNIKOV I.A.

    2016-01-01

    Shungites have been studied by high-resolution transmission electron microscopy (HRTEM). Two types of carbon layers have been revealed in shungites by HRTEM. The first type, graphite-like carbon layers are characterized by strongly marked hexagonal symmetry. The second type are remarkable for imperfections connected with insignificant disorder in the direction of fringes and the distance between them, and can result from point defects or the pentagonal and heptagonal carbon rings that are sig...

  17. Effect of crop residue harvest on long-term crop yield, soil erosion, and carbon balance: tradeoffs for a sustainable bioenergy feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, Jay S.; Izaurralde, Roberto C.

    2010-08-26

    Agricultural residues are a potential feedstock for bioenergy production, if residue harvest can be done sustainably. The relationship between crop residue harvest, soil erosion, crop yield and carbon balance was modeled with the Erosion Productivity Impact Calculator/ Environment Policy Integrated Climate (EPIC) using a factorial design. Four crop rotations (winter wheat [Triticum aestivum (L.)] – sunflower [Helianthus annuus]; spring wheat [Triticum aestivum (L.)] – canola [Brassica napus]; corn [Zea mays L.] – soybean [Glycine max (L.) Merr.]; and cotton [Gossypium hirsutum] – peanut [Arachis hypogaea]) were simulated at four US locations each, under different topographies (0-10% slope), and management practices [crop residue removal rates (0-75%), conservation practices (no till, contour cropping, strip cropping, terracing)].

  18. Developing and using a balanced scorecard: a case study with SWOT analysis.

    Science.gov (United States)

    Gumbus, Andra; Lussier, Robert N

    2003-01-01

    Have you tried to measure your laboratory's performance lately? Do you measure and assess financial results, customer satisfaction, internal process efficiency, and learning and growth? If any of these metrics are missing from your performance measurement system, you are not using the latest management tool that is sweeping the health-care industry--the balanced scorecard (BSC). This article begins with a discussion of the BSC and why you should use it in your laboratory, followed by SWOT analysis to assess the strengths, weaknesses, opportunities, and threats (SWOT) a BSC offers your laboratory. A laboratory case study is then presented to assist you in developing and using a BSC in your laboratory. PMID:12701559

  19. Status of FY 1988 soil-water balance studies on the Hanford site

    Energy Technology Data Exchange (ETDEWEB)

    Gee, G.W.; Rockhold, M.L.; Downs, J.L.

    1989-02-01

    Natural recharge (i.e., the amount of water from meteorological sources, such as rainfall or snowmelt, that infiltrates through the vadose zone to the groundwater table) at the Hanford Site is a variable quantity because it depends on soil, plant, and climatic factors that vary in time and space over the Site. Water balance data have been collected at selected locations at the Hanford Site for the past 10 years in an attempt to measure or estimate natural recharge for known soil, plant, and climatic conditions. The data collected include precipitation, neutron probe measured water content (storage), and drainage measurements from lysimeters. The lysimeter studies provided the first quantitative estimates of natural recharge at the Hanford Site. 12 refs., 40 figs., 11 tabs.

  20. Thermal acclimation of leaf respiration of tropical trees and lianas: response to experimental canopy warming, and consequences for tropical forest carbon balance.

    Science.gov (United States)

    Slot, Martijn; Rey-Sánchez, Camilo; Gerber, Stefan; Lichstein, Jeremy W; Winter, Klaus; Kitajima, Kaoru

    2014-09-01

    Climate warming is expected to increase respiration rates of tropical forest trees and lianas, which may negatively affect the carbon balance of tropical forests. Thermal acclimation could mitigate the expected respiration increase, but the thermal acclimation potential of tropical forests remains largely unknown. In a tropical forest in Panama, we experimentally increased nighttime temperatures of upper canopy leaves of three tree and two liana species by on average 3 °C for 1 week, and quantified temperature responses of leaf dark respiration. Respiration at 25 °C (R25 ) decreased with increasing leaf temperature, but acclimation did not result in perfect homeostasis of respiration across temperatures. In contrast, Q10 of treatment and control leaves exhibited similarly high values (range 2.5-3.0) without evidence of acclimation. The decrease in R25 was not caused by respiratory substrate depletion, as warming did not reduce leaf carbohydrate concentration. To evaluate the wider implications of our experimental results, we simulated the carbon cycle of tropical latitudes (24°S-24°N) from 2000 to 2100 using a dynamic global vegetation model (LM3VN) modified to account for acclimation. Acclimation reduced the degree to which respiration increases with climate warming in the model relative to a no-acclimation scenario, leading to 21% greater increase in net primary productivity and 18% greater increase in biomass carbon storage over the 21st century. We conclude that leaf respiration of tropical forest plants can acclimate to nighttime warming, thereby reducing the magnitude of the positive feedback between climate change and the carbon cycle.

  1. Noninvasive radioelectric asymmetric conveyor brain stimulation treatment improves balance in individuals over 65 suffering from neurological diseases: pilot study

    Directory of Open Access Journals (Sweden)

    Margotti ML

    2012-02-01

    Full Text Available Vania Fontani1, Salvatore Rinaldi1, Alessandro Castagna1, Matteo Lotti Margotti21Department of Neuro Psycho Physio Pathology, Rinaldi Fontani Institute, Florence, Italy; 2Department of Information Technology and Statistical Analysis, Rinaldi Fontani Institute, Florence, ItalyPurpose: In the elderly population, problems with walking and balance are very common. These problems seriously affect the quality of life of the elderly. When gait and balance problems are caused by neurological disease, these problems can be more serious and difficult to handle. The aim of this pilot study was to verify the effect of a noninvasive radioelectric conveyor asymmetric brain stimulation protocol, named neuropostural optimization (NPO, to improve balance in neurological elderly.Patients and methods: Twelve patients suffering from various neurological diseases participated in this study. They were assessed with the Romberg test, which was performed on a computerized stabilometric platform before, immediately following, and 72 hours after NPO was used to improve balance.Results: The results showed that a stabilization of balance was recorded in all subjects a few minutes after administration of NPO. This stabilization increased 72 hours after treatment.Conclusion: The results show that NPO could be a valuable therapeutic approach to improve sensory-motor strategies and neurological control of balance in elderly patients suffering from various neurological diseases.Keywords: Romberg test, instability, imbalance, gait, REAC, neuropostural optimization

  2. The effect of therapeutic horseback riding on balance in community-dwelling older adults: a pilot study.

    Science.gov (United States)

    Homnick, Tamara D; Henning, Kim M; Swain, Charlene V; Homnick, Douglas N

    2015-02-01

    Equine assisted activities (hippotherapy and therapeutic riding) improve balance in patients with disabilities such as cerebral palsy, but have not been systematically studied in older adults, at risk of falls due to balance deficits. We conducted a 10-week, single blind, controlled trial of the effect of a therapeutic horseback riding course on measures of balance in community-dwelling adults 65 years and older. Nine riders and six controls completed the trial. Controls were age matched to riders and all participants were recruited from the local community. Both groups showed improvements in balance during the trial, but did not reach statistical significance. Sample size was small, participants had relatively high initial balance scores, and controls tended to increase their physical activities, likely influencing outcomes. No adverse events occurred and the supervised therapeutic riding program appeared to be a safe and effective form of exercise to improve balance in older adults. A power analysis was performed to estimate numbers of participants needed for a larger study.

  3. Phenology, canopy aging and seasonal carbon balance as related to delayed winter pruning of Vitis vinifera L. cv. Sangiovese grapevines

    OpenAIRE

    Matteo eGatti; Facundo Jose ePirez; Giorgio eChiari; Sergio eTombesi; Alberto ePalliotti; Maria Clara eMerli; Stefano ePoni

    2016-01-01

    Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mechanistic hypothesis underlying this work was that very late winter pruning can achieve significant postponement of phenological stages so that ripen...

  4. Phenology, Canopy Aging and Seasonal Carbon Balance as Related to Delayed Winter Pruning of Vitis vinifera L. cv. Sangiovese Grapevines

    OpenAIRE

    Gatti, Matteo; Pirez, Facundo J.; Chiari, Giorgio; Tombesi, Sergio; Palliotti, Alberto; Merli, Maria C.; Poni, Stefano

    2016-01-01

    Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mechanistic hypothesis underlying this work was that very late winter pruning (LWP) can achieve significant postponement of phenological stages so that...

  5. Water balance at an arid site: a model validation study of bare soil evaluation

    International Nuclear Information System (INIS)

    This report contains results of model validation studies conducted by Pacific Northwest Laboratory (PNL) for the Department of Energy's (DOE) National Low Level Waste Management Program (NLLWMP). The model validation tests consisted of using unsaturated water flow models to simulate water balance experiments conducted at the Buried Waste Test Facility (BWTF) located at the Department of Energy's Hanford site, near Richland, Washington. The BWTF is a lysimeter facility designed to collect field data on long-term water balance and radionuclide tracer movement. It has been operated by PNL for the NLLWMP since 1978. An experimental test case, developed from data collected at the BWTF, was used to evaluate predictions from different water flow models. The major focus of the validation study was to evaluate how the use of different evaporation models affected the accuracy of predictions of evaporation, storage, and drainage made by the whole model. Four evaporation models were tested including two empirical models and two mechanistic models. The empirical models estimate actual evaporation from potential evaporation; the mechanistic models describe water vapor diffusion within the soil profile and between the soil and the atmosphere in terms of fundamental soil properties, and transport processes. The water flow models that included the diffusion-type evaporation submodels performed best overall. The empirical models performed poorly in their description of evaporation and profile water storage during summer months. The predictions of drainage were supported quite well by the experimental data. This indicates that the method used to estimate hydraulic conductivity needed for the Darcian submodel was adequate. This important result supports recommendations for these procedures that were made previously based on laboratory results

  6. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance

    OpenAIRE

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn sto...

  7. CUES - A Study Site for Measuring Snowpack Energy Balance in the Sierra Nevada

    Science.gov (United States)

    Bair, Edward; Dozier, Jeff; Davis, Robert; Colee, Michael; Claffey, Keran

    2015-09-01

    Accurate measurement and modeling of the snowpack energy balance are critical to understanding the terrestrial water cycle. Most of the water resources in the western US come from snowmelt, yet statistical runoff models that rely on the historical record are becoming less reliable because of a changing climate. For physically based snow melt models that do not depend on past conditions, ground based measurements of the energy balance components are imperative for verification. For this purpose, the US Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL) and the University of California, Santa Barbara (UCSB) established the “CUES” snow study site (CRREL/UCSB Energy Site, http://www.snow.ucsb.edu/) at 2940 m elevation on Mammoth Mountain, California. We describe CUES, provide an overview of research, share our experience with scientific measurements, and encourage future collaborative research. Snow measurements began near the current CUES site for ski area operations in 1969. In the 1970s, researchers began taking scientific measurements. Today, CUES benefits from year round gondola access and a fiber optic internet connection. Data loggers and computers automatically record and store over 100 measurements from more than 50 instruments each minute. CUES is one of only five high altitude mountain sites in the Western US where a full suite of energy balance components are measured. In addition to measuring snow on the ground at multiple locations, extensive radiometric and meteorological measurements are recorded. Some of the more novel measurements include scans by an automated terrestrial LiDAR, passive and active microwave imaging of snow stratigraphy, microscopic imaging of snow grains, snowflake imaging with a multi-angle camera, fluxes from upward and downward looking radiometers, snow water equivalent from different types of snow pillows, snowmelt from lysimeters, and concentration of impurities in the snowpack. We give an

  8. CUES – A Study Site for Measuring Snowpack Energy Balance in the Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Edward H. Bair

    2015-09-01

    Full Text Available Accurate measurement and modeling of the snowpack energy balance are critical to understanding the terrestrial water cycle. Most of the water resources in the western US come from snowmelt, yet statistical runoff models that rely on the historical record are becoming less reliable because of a changing climate. For physically based snow melt models that do not depend on past conditions, ground based measurements of the energy balance components are imperative for verification. For this purpose, the US Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL and the University of California, Santa Barbara (UCSB established the CUES snow study site (CRREL/UCSB Energy Site, http://www.snow.ucsb.edu/ at 2940 m elevation on Mammoth Mountain, California. We describe CUES, provide an overview of research, share our experience with scientific measurements, and encourage future collaborative research. Snow measurements began near the current CUES site for ski area operations in 1969. In the 1970s, researchers began taking scientific measurements. Today, CUES benefits from year round gondola access and a fiber optic internet connection. Data loggers and computers automatically record and store over 100 measurements from more than 50 instruments each minute. CUES is one of only five high altitude mountain sites in the Western US where a full suite of energy balance components are measured. In addition to measuring snow on the ground at multiple locations, extensive radiometric and meteorological measurements are recorded. Some of the more novel measurements include scans by an automated terrestrial LiDAR, passive and active microwave imaging of snow stratigraphy, microscopic imaging of snow grains, snowflake imaging with a multi-angle camera, fluxes from upward and downward looking radiometers, snow water equivalent from different types of snow pillows, snowmelt from lysimeters, and concentration of impurities in the snowpack. We

  9. The 'Bilan Carbone'. Overview of a carbon balance method allowing to evaluate company's exposure to fossil energy costs fluctuation

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, Sylvie; Galio, Pierre [ADEME - French Agency for Environment and Energy Management, Angers (France)

    2007-07-01

    90 % of the carbon dioxide emitted comes from the combustion of fossil energies (petroleum products, coal and natural gas) and is therefore directly related to energy consumption. The European Union has committed to reducing its greenhouse gas emissions by 8 % by 2008-2012 in relation to levels recorded in 1990 (Kyoto Protocol). This commitment involves for the European Union an ambitious policy aiming at making industries more energy efficient with three main goals:cutting the high cost of energy; reducing fossils energies addiction; launching an emissions reduction process. ADEME (French Agency for Environment and Energy Management) developed a simple method which is an effective solution for ranking emissions by source and for launching a dynamic emissions reduction process: the Bilan Carbone Method.Bilan Carbone is both a tool and a methodology. The main component of the tool is a ready-to-use Excel spreadsheet that calculates the emissions caused by all the processes necessary for the existence of a given activity. Space heating, combustion for manufacturing processes, but also freight shipments, passengers travel, production of raw materials used, waste treatment - To take these items into account, simply fill in the spreadsheet with energy consumption figures, kilometers travelled, quantities of materials purchased, etc. For each source of CO{sub 2} or other greenhouse gases, theses data are then converted by the spreadsheet into the amount of carbon emitted, using fully documented emissions factors. The general spirit of the Bilan Carbone method is to provide the broadest possible panorama of emissions that are linked to processes used by a company or an organization. This is also the only approach that is pertinent for looking forward and anticipating the effect of possible trends, for instance a significant rise in the market price of fossil energy.In practice, the accuracy of the results will depend to a large extent on the amount of time spent

  10. Covariate balance assessment, model selection and bias in propensity score matching: A simulation study

    NARCIS (Netherlands)

    Ali, Sanni; Groenwold, Rolf H.H.; Belitser, S.; Roes, Kit C.B.; Hoes, Arno W.; De Boer, Anthonius; Klungel, Olaf H.

    2015-01-01

    Background: In building propensity score (PS) model, inclusion of interaction/square terms in addition to the main terms and the use of balance measures has been suggested. However, the impact of assessing balance of several sets of covariates and their interactions/squares on bias/precision is not

  11. A study on the cytotoxicity of carbon-based materials.

    Science.gov (United States)

    Saha, Dipendu; Heldt, Caryn L; Gencoglu, Maria F; Vijayaragavan, K Saagar; Chen, Jihua; Saksule, Ashish

    2016-11-01

    With an aim to understand the origin and key contributing factors towards carbon-induced cytotoxicity, we have studied five different carbon samples with diverse surface area, pore width, shape and size, conductivity and surface functionality. All the carbon materials were characterized with surface area and pore size distribution, X-ray photoelectron spectroscopy (XPS) and electron microscopic imaging. We performed cytotoxicity study in Caco-2 cells by colorimetric assay, oxidative stress analysis by reactive oxygen species (ROS) detection, cellular metabolic activity measurement by adenosine triphosphate (ATP) depletion and visualization of cellular internalization by TEM imaging. The carbon materials demonstrated a varying degree of cytotoxicity in contact with Caco-2 cells. The lowest cell survival rate was observed for nanographene, which possessed the minimal size amongst all the carbon samples under this study. None of the carbons induced oxidative stress to the cells as indicated by the ROS generation results. Cellular metabolic activity study revealed that the carbon materials caused ATP depletion in cells and nanographene caused the highest depletion. Visual observation by TEM imaging indicated the cellular internalization of nanographene. This study confirmed that the size is the key cause of carbon-induced cytotoxicity and it is probably caused by the ATP depletion within the cell. PMID:27524001

  12. Eldecalcitol improves muscle strength and dynamic balance in postmenopausal women with osteoporosis: an open-label randomized controlled study.

    Science.gov (United States)

    Saito, Kimio; Miyakoshi, Naohisa; Matsunaga, Toshiki; Hongo, Michio; Kasukawa, Yuji; Shimada, Yoichi

    2016-09-01

    The antifracture efficacy of vitamin D in osteoporosis is due to its direct action on bones and indirect extraskeletal effects to prevent falls. Eldecalcitol is an analog of active vitamin D3 that improves bone mineral density and reduces the risk of osteoporotic fractures. However, the effects of eldecalcitol on muscle strength and static and dynamic postural balance are unclear. In this open-label randomized controlled study, we assessed the effects of eldecalcitol on muscle strength and static and dynamic postural balance in 50 postmenopausal women (mean age 74 years) with osteoporosis treated with bisphosphonate. Participants were randomly divided into a bisphosphonate group (alendronate at 35 mg/week; n = 25) or an eldecalcitol group (eldecalcitol at 0.75 μg/day and alendronate at 35 mg/week; n = 25) and were followed up for 6 months. Trunk muscle strength, including back extensor strength and iliopsoas muscle strength, was measured. Static standing balance was evaluated and the one leg standing test was performed to assess static postural balance. Dynamic sitting balance was evaluated and the 10-m walk test, functional reach test, and timed up and go test were performed to assess dynamic postural balance. At 6 months, there were no significant changes in any measure of muscle strength or balance in the bisphosphonate group, whereas eldecalcitol significantly increased back extensor strength (p = 0.012) and iliopsoas muscle strength (p = 0.035). Eldecalcitol also significantly improved findings on the timed up and go test (p = 0.001) and dynamic sitting balance (p = 0.015) at 6 months. These results with eldecalcitol may have an impact on prevention of falls.

  13. Assessing the Atmospheric Oxygen Balance in a Region of Rapid Urbanization: A Case Study in the Pearl River Delta, China

    Directory of Open Access Journals (Sweden)

    Jian Peng

    2015-09-01

    Full Text Available Oxygen is a product of photosynthesis and is essential for human survival. It also has a profound effect on ecosystems as the atmospheric oxygen balance is the basis for regional ecological sustainability. The Pearl River Delta (PRD has experienced rapid urbanization and has become one of China’s three major urban agglomerations. This study focused on the oxygen balance of the PRD in 2011, and established a model to calculate the oxygen balance that was suitable for a region of rapid urbanization by applying remote sensing gross primary production data via the C-Fix model. The influencing factors for the oxygen imbalance were analyzed and it was suggested that more attention be paid to the management of oxygen emissions than oxygen consumption. The results indicated that the oxygen balance capacity of the PRD was weak, with an oxygen consumption 9.37 times that of its oxygen emission. Zhaoqing and Huizhou are the main sources of oxygen in the PRD, with an oxygen emission density more than 4.67 times that of Dongguan or Zhuhai. Guangzhou and Shenzhen are the main oxygen sinks, with a total oxygen consumption more than 5.49 times that of Zhaoqing. Moreover, the oxygen balance of the PRD is more sensitive to oxygen emissions than consumption. Therefore, it could be inferred that the land urbanization has a stronger influence on the oxygen balance than the population urbanization.

  14. Strategic Planning Model Formulation Based on Balanced Score Card: A Case Study

    Directory of Open Access Journals (Sweden)

    Elaheh Enteshari Najaf Abadi

    2012-07-01

    Full Text Available At the present age, strategic planning is considered as an important and vital matter for organizations and formulating and implementing strategic plans and accurate parameters may result in organizations long-term superiority in competitive field. But, regarding that competitive factors of all organizations are not the same, formulating the strategy with a similar trend is unlikely to be effective and the prerequisite for success of any organization is to focus and pay attention to its own capacities and unique competitive advantages and to formulate strategies based on those capacities along with focusing on the weakness and threats points. This article presents a model integrated of the strategic planning process and balanced score card and considering four dimensions of the Balanced Score Card (BSC, it accomplishes the process of strategic planning in the fields of financial, customer, internal processes and growth and learning separately and then determines the position of an organization in each dimension. Therefore, the strength and weakness points of the organization are identified and the type of strategies needed for any dimension determined separately. With the aid of this model, top managers are able to determine the organization expects and goals of different sectors clearly and in line with the vision and strategy of organization and deliver to the managers and authorities of different sectors. The results of this model are the analysis of factors influencing on the strategy formulation, extraction of key dimensions, provision of the SWOT matrix for four-folds dimensions of BSC and the identification of organization situation in each dimension such that through basing it on, integrated strategies and operational plans will be formulated for the organization. In this survey, Isfahan Company of tile industry has been studied as a sample and the results of the model implementation for this company described in the text.

  15. Strong magnetism observed in carbon nanoparticles produced by the laser vaporization of a carbon pellet in hydrogen-containing Ar balance gas.

    Science.gov (United States)

    Asano, Hirohito; Muraki, Susumu; Endo, Hiroki; Bandow, Shunji; Iijima, Sumio

    2010-08-25

    Nanometer-scale carbon particles driven by the pulsed-laser vaporization of pelletized pure carbon powder at 1000 °C in a hydrogen-containing environment show anomalous magnetism like a superparamagnet, while the sample prepared in 100% of Ar does not show such magnetism. The observed magnetism was unchanged over months in the ambient. The structure of this nanomaterial resembles the foam of a laundry detergent and transmission electron microscopy indicates a clear corrugated line contrast. On the other hand, a sample without strong magnetism does not give such an image contrast. The x-ray diffraction pattern coincides with that of graphite and no other peak is detected. Thermogravimetry indicates that all samples completely burn out up to approx. 820 °C and no material remains after combustion, indicating that the sample does not contain impurity metals. Magnetization is easily saturated by ∼10,000 G at 280 K with no hysteresis, but the hysteresis appears at 4.2 K. This phenomenon is explained by introducing a crystalline anisotropy which restricts the motion of the magnetic moment and stabilizes the remnant magnetization at zero magnetic field. Magnitudes of the saturation magnetization are in the range of 1-5 emu G g(-1) at 4.2 K, which correspond to 0.002-0.01 Bohr magneton per carbon atom. This concentration may be increased by ten times or more, because only about 4-10% of particles have a magnetic domain in the present samples.

  16. Developing Carbon Budgets for Cities: Phoenix as a Case Study

    Science.gov (United States)

    McHale, M. R.; Baker, L. A.; Koerner, B. A.; Grimm, N. B.

    2008-12-01

    Studies have shown that cities can alter regional carbon dynamics through changing ecosystem productivity, overall carbon cycling rate, and total carbon storage in vegetation and soils. Furthermore, people in urban regions import a large amount of carbon in food and fuel, as well as release an exceptional amount of CO2 into the atmosphere. Numerous studies have attempted to quantify some sources and sinks of carbon in urban areas, although a complete carbon budget for a city that accounts for total inputs, outputs, and storage within the ecosystem has yet to be fully accomplished. One challenge is associated with attaining the data necessary to accurately account for all carbon dynamics in these heterogeneous and complex ecosystems. Our goal was to estimate a budget for the Phoenix metropolitan area while developing methodology to calculate carbon dynamics in urban systems that can be applied to cities across the US. Only with comparable carbon budgets for multiple cities will we finally begin to understand the influence of urbanization on carbon dynamics. Our analysis shows when calculating certain variables like transportation emissions, results can vary radically (up to 250%) depending on the data source and methodology implemented (i.e. bottom-up vs. top-down). A common assumption is that productivity and carbon storage will increase with urbanization in arid systems due to water and nutrient inputs, as well as changes in vegetation structure; however, our results indicated that this may not actually be the case in Phoenix where a large number of residents design landscapes to conserve water. Even if all urban expansion was dedicated to landscapes designed for carbon sequestration and storage, vegetation and soils will unlikely have a large effect on the C budget without significant changes in transportation and lifestyle choices.

  17. Computational studies of small carbon and iron-carbon systems relevant to carbon nanotube growth.

    Science.gov (United States)

    Duan, Haiming; Rosén, Arne; Harutyunyan, Avetik; Curtarolo, Stefano; Bolton, Kim

    2008-11-01

    Density functional theory (DFT) calculations show that dimers and longer carbon strings are more stable than individual atoms on Fe(111) surfaces. It is therefore necessary to consider the formation of these species on the metal surfaces and their effect on the mechanism of single-walled nanotube (SWNT) growth. The good agreement between the trends (energies and structures) obtained using DFT and those based on the Brenner and AIREBO models indicate that these analytic models provide adequate descriptions of the supported carbon systems needed for valid molecular dynamics simulations of SWNT growth. In contrast, the AIREBO model provides a better description of the relative energies for isolated carbon species, and this model is preferred over the Brenner potential when simulating SWNT growth in the absence of metal particles. However, the PM3 semiempirical model appears to provide an even better description for these systems and, given sufficient computer resources, direct dynamics methods based on this model may be preferred.

  18. Carbon balance: the top-down and bottom-up emissions accounting methodologies; Balanco de carbono: a contabilidade das emissoes nas metodologias 'Top-Down' estendida ('Top-Bottom') e 'Bottom-Up'

    Energy Technology Data Exchange (ETDEWEB)

    Alvim, Carlos Feu; Eidelman, Frida; Ferreira, Omar Campos

    2005-08-15

    The Economy and Energy Organization has carried out together with the Ministry of Science and Technology a study on the carbon balance of energy use and transformation. The publication of its results has been made through the e and e periodical in its 48 and 50 issues. In the present issue we are publishing the results corresponding to the extended Top-Down accounting process and those corresponding to the use of the coefficients calculated for the Brazilian inventory from 1990 to 1994, using the Bottom-Up process, to estimate the emissions from 1970 to 2002. By comparing the two results it is possible to evaluate their deficiencies and the possible incoherence in the use of the two methodologies. (author)

  19. Studies of DNA-carbon nanotube interactions

    Science.gov (United States)

    Hughes, Mary Elizabeth

    2008-10-01

    Recently a new biomaterial consisting of a DNA-wrapped single-walled carbon nanotube, and known as a DNA/SWNT, has been discovered. The possible applications of this hybrid are varied and range from genomic sequencing to nanoscale electronics to molecular delivery. The realization of these potential applications requires more knowledge about the microscopic properties of this material. In this thesis, I present studies of: the orientation of nucleobases on the nanotube sidewall; the sequence and length dependence of the DNA-nanotube interaction; and solution conditions to manipulate the DNA/SWNT hybrid. The measurement of the UV optical absorbance of DNA/SWNT and the nucleotide absorbance from DNA/SWNT provide the first experimental confirmation that DNA binds to nanotubes through pi-stacking. Because the hypochromic absorbance typical of pi-stacked structures are expected to occur primarily for DNA dipole transitions that lie along the axis of the optically anisotropic SWNTs, the absorbance changes following binding of DNA to the nanotubes reveals the preferred orientation assumed by each of the four bound nucleotides with respect to the nanotube's long axis. The first observations of pronounced sequence- and length-dependent variations in the binding between ssDNA and SWNTs in aqueous solution are presented. These observations rely on the discovery that there exists a range of DNA lengths able to hybridize with SWNTs that can nevertheless be dissociated at temperatures below the boiling point of water. Quantitative results comparing the isochronal dissociation temperatures and binding energies of DNA/SWNT composed of differing DNA sequences and lengths are given. These results indicate variability and complexity in the binding mechanism responsible for the stability of the hybrid system that transcends simple models based on the sum of independent base-nanotube interactions. Binding energies between a DNA base and nanotube (0.05 to 0.09 eV per base) are similar

  20. Improved constraints on in situ rates and on quantification of complete chloroethene degradation from stable carbon isotope mass balances in groundwater plumes

    Science.gov (United States)

    Höhener, Patrick; Elsner, Martin; Eisenmann, Heinrich; Atteia, Olivier

    2015-11-01

    Spills of chloroethenes (CEs) at industrial and urban sites can create groundwater plumes in which tetrachloro- and trichloroethene sequentially degrade to dichloroethenes, vinyl chloride (VC) and ethene, or ethane under reducing conditions. For detoxification, degradation must go beyond VC. Assessments based on ethene and ethane, however, are difficult because these products are volatile, may stem from alternative sources, can be further transformed and are not always monitored. To alternatively quantify degradation beyond VC, stable carbon isotope mass balances have been proposed where concentration-weighted CE isotope ratios are summed up and compared to the original source isotope ratio. Reported assessments, however, have provided not satisfactorily quantified results entailing greatly differing upper and lower estimates. This work proposes an integrative approach to better constrain the extent of total chloroethene degradation in groundwater samples. It is based on fitting of measured concentration and compound-specific stable carbon isotope data to an analytical reactive transport equation simulating steady-state plumes in two dimensions using an EXCEL spreadsheet. The fitting also yields estimates of degradation rates, of source width and of dispersivities. The approach is validated using two synthetic benchmark cases where the true extent of degradation is well known, and using data from two real field cases from literature.

  1. Alternate strategies to obtain mass balance without the use of radiolabeled compounds: application of quantitative fluorine (19F) nuclear magnetic resonance (NMR) spectroscopy in metabolism studies.

    Science.gov (United States)

    Mutlib, Abdul; Espina, Robert; Atherton, James; Wang, Jianyao; Talaat, Rasmy; Scatina, JoAnn; Chandrasekaran, Appavu

    2012-03-19

    Nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in the quantitation of small and large molecules. Recently, we demonstrated that (1)H NMR could be used to quantitate drug metabolites isolated in submilligram quantities from biological sources. It was shown that these metabolites, once quantitated by NMR, were suitable to be used as reference standards in quantitative LC/MS-based assays, hence circumventing the need for radiolabeled material or synthetic standards to obtain plasma exposure estimates in humans and preclinical species. The quantitative capabilities of high-field NMR is further demonstrated in the current study by obtaining the mass balance of fluorinated compounds using (19)F-NMR. Two fluorinated compounds which were radio-labeled with carbon-14 on metabolically stable positions were dosed in rats and urine and feces collected. The mass balance of the compounds was obtained initially by counting the radioactivity present in each sample. Subsequently, the same sets of samples were analyzed by (19)F-NMR, and the concentrations determined by this method were compared with data obtained using radioactivity counting. It was shown that the two methods produced comparable values. To demonstrate the value of this analytical technique in drug discovery, a fluorinated compound was dosed intravenously in dogs and feces and urine collected. Initial profiling of samples showed that this compound was excreted mainly unchanged in feces, and hence, an estimate of mass balance was obtained using (19)F-NMR. The data obtained by this method was confirmed by additional quantitative studies using mass spectrometry. Hence cross-validations of the quantitative (19)F-NMR method by radioactivity counting and mass spectrometric analysis were demonstrated in this study. A strategy outlining the use of fluorinated compounds in conjunction with (19)F-NMR to understand their routes of excretion or mass balance in animals is proposed. These

  2. Studies on copper coating on carbon fibers

    Institute of Scientific and Technical Information of China (English)

    CAO; Zhuo-kun; LIU; Yi-han; YAO; Guang-chun

    2005-01-01

    The weak interface bonding of metal matrix reinforced by carbon fibers is the central problem of fabricating such composites. Depositing copper coating on carbon fibers is regarded as a feasible method to solve the problem. In this paper, copper coating has been deposited on the fibers through both electroless deposition and electroplating methods. Two kinds of complexing agents and two stabilizing agents are taken during the electroless plating process. The solution is stable, and little extraneous component is absorbed on the surface. After adding additive agents and increasing the concentration of H2SO4 to the acid cupric sulfate electrolyte, the "black core" during usual electroplating process is avoided. The quality of copper coating is analyzed using SEM and XRD, etc.

  3. Studies on carbon budget score remarkable progress

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ On 23 November, 2006, a key CAS research project on carbon budget passed the review by a panel of experts under the joint auspices of the CAS Bureau of Comprehensive Planning and the CAS Bureau of Science and Technology for Resourc es and Environment. The panel was made up of 11 prestigious experts, led by CHEN Yiyu, a CAS Member and President of National Natural Sciences Foundation of China.

  4. Balancing Risk

    DEFF Research Database (Denmark)

    Nygaard, Lene; Rossen, Camilla Blach; Buus, Niels

    2015-01-01

    This study explored how eight pregnant women diagnosed with depression managed the decision whether or not to take antidepressants during pregnancy. In total, 11 interviews were conducted and analysed by means of constructivist grounded theory. The major category constructed was Balancing risk......, with two minor categories: Assessing depression and antidepressants and Evaluating the impact of significant others. The participants tried to make the safest decision, taking all aspects of their life into consideration. They described successful decision-making in the context of managing social norms...

  5. Performance measurement using balanced scorecard: A case study of pipe industry

    Directory of Open Access Journals (Sweden)

    Amer Hosseini

    2013-05-01

    Full Text Available Strategic assessment of the organizational performance in the industrial environment is one of the primary and essential prerequisites for developing improvement plans in organizations. This issue is so crucial that one of the on-going affairs in the organizations is to identify the weakness and strength points. One of the effective models for assessing the organizations performance is balance scorecard (BSC model, which examines all the aspects of an organization. The proposed study of this paper investigates the existing strategic objectives in the strategy map of a pipe company located in city of Shiraz, Iran. The proposed study of this paper designs a questionnaire and distributes it among 31 managers, 94 regular employees and 110 customers of this firm for the fiscal year ended 2011. The results of our study indicate that the firm could reach 41.4% of its financial objectives, 87.38% of its customers’ requirements, 66.13% of internal processes and 70.94% of its learning necessities according to four major BSC requirements. In summary, the firm could reach 66.45 % of its requirements during the fiscal year of 2011.

  6. The ANIBES Study on Energy Balance in Spain: Design, Protocol and Methodology

    Directory of Open Access Journals (Sweden)

    Emma Ruiz

    2015-02-01

    Full Text Available Energy Balance (EB is an important topic to understand how an imbalance in its main determinants (energy intake and consumption may lead to inappropriate weight gain, considered to be “dynamic” and not “static”. There are no studies to evaluate EB in Spain, and new technologies reveal themselves as key tools to solve common problems to precisely quantify energy consumption and expenditure at population level. The overall purpose of the ANIBES (“Anthropometry, Intake and Energy Balance” Study was to carry out an accurate updating of food and beverage intake, dietary habits/behaviour and anthropometric data of the Spanish population (9–75 years, n = 2009, as well as the energy expenditure and physical activity patterns. Anthropometry measurements (weight, height, body mass index, waist circumference, % body fat, % body water were obtained; diet was evaluated throughout a three-day dietary record (tablet device accompanied by a 24 h-dietary recall; physical activity was quantified by questionnaire and accelerometers were also employed. Finally, information about perception and understanding of several issues related to EB was also obtained. The ANIBES study will contribute to provide valuable useful data to inform food policy planning, food based dietary guidelines development and other health oriented actions in Spain.

  7. Balancing Study and Paid Work: The Experiences of Construction Undergraduates in an Australian University

    Directory of Open Access Journals (Sweden)

    Helen Lingard

    2012-11-01

    Full Text Available A questionnaire survey was undertaken among third year studentsenrolled in the University of Melbourne’s Bachelor of Property andConstruction (BPC programme. The survey explored students’experiences in balancing paid work with study. Hours spent in paidemployment were at least as long and, in many cases, were inexcess of hours spent at university. While work was not perceivedby students to pose a difficulty for attending lectures and tutorials,students indicated that their paid work made it difficult for them toengage in independent learning activities, such as using libraryresources or preparing for classes by reading beforehand. Twoscales, previously used in other countries to measure students’burnout and engagement, were tested. Both scales were foundto be valid and reliable in that the factorial structures foundin previous studies were confirmed and acceptable internalconsistency reliability coefficients were generated for each of thescales’ component factors. This opens the way for more in-depthmultivariate analysis to determine the linkages between workhours, work-study conflict and students’ burnout or engagementwith university life.

  8. Workload Balancing on Heterogeneous Systems: A Case Study of Sparse Grid Interpolation

    KAUST Repository

    Muraraşu, Alin

    2012-01-01

    Multi-core parallelism and accelerators are becoming common features of today’s computer systems, as they allow for computational power without sacrificing energy efficiency. Due to heterogeneity, tuning for each type of compute unit and adequate load balancing is essential. This paper proposes static and dynamic solutions for load balancing in the context of an application for visualizing high-dimensional simulation data. The application relies on the sparse grid technique for data compression. Its performance critical part is the interpolation routine used for decompression. Results show that our load balancing scheme allows for an efficient acceleration of interpolation on heterogeneous systems containing multi-core CPUs and GPUs.

  9. [Study on absorbing volatile oil with mesoporous carbon].

    Science.gov (United States)

    Yan, Hong-mei; Jia, Xiao-bin; Zhang, Zhen-hai; Sun, E; Yang Nan

    2014-11-01

    Clove oil and turmeric oil were absorbed by mesoporous carbon. The absorption ratio of mesoporous carbon to volatile oil was optimized with the eugenol yield and curcumol yield as criteria Curing powder was characterized by scanning electron microscopy (SEM) and differential scanning calorietry (DSC). The effects of mesoporous carbon on dissolution in vitro and thermal stability of active components were studied. They reached high adsorption rate when the absorption ratio of mesoporous carbon to volatile oil was 1:1. When volatile oil was absorbed, dissolution rate of active components had a little improvement and their thermal stability improved after volatile oil was absorbed by the loss rate decreasing more than 50%. Absorbing herbal volatile oil with mesoporous carbon deserves further studying. PMID:25850263

  10. Balance Between Autotrophic and Heterotrophic Components and Processes in Microbenthic Communities of Sandy Sediments: A Field Study

    Science.gov (United States)

    Sundbäck, Kristina; Nilsson, Per; Nilsson, Claes; Jönsson, Benno

    1996-12-01

    The microscopic community of a microtidal sandy sediment on the Swedish west coast was studied in situat two depths (0·5 and 4 m) on four occasions (January, April, August and October). Biomass of microalgae, bacteria, ciliates and meiofauna, as well as primary and bacterial productivity, were quantified. Meiofaunal grazing on algae and bacteria was measured simultaneously by radiolabelling intact sediment cores. Autotrophic biomass dominated the microbial community at both depths and on all sampling occasions, accounting for 47-87% of the microbial biomass. Meiofauna contributed 10-47%, while bacteria and ciliates together made up less than 6%. The microflora was dominated by attached (epipsammic) diatoms, but occasional ' blooms ' of motile species occurred. Vital cells of planktonic diatoms contributed to benthic algal biomass in spring. Primary productivity exceeded bacterial productivity in April and August at both depths, while the balance was reversed in October and January. Meiofauna grazed between 2 and 12% of the algal biomass per day, and between 0·3 and 37% of the bacterial biomass. Almost an order of magnitude more algal (17-138 mg C m -2) than bacterial (0·1-33 mg C m -2) carbon was grazed daily. At the shallow site, primary productivity always exceeded grazing rates on algae, whereas at the deeper site, grazing exceeded primary productivity in October and January. Bacterial productivity exceeded grazing at both depths on all four occasions. Thus, meiofaunal grazing seasonally controlled microalgal, but not bacterial, biomass. These results suggest that, during summer, only a minor fraction (food web ' through meiofauna. During spring and autumn, however, a much larger fraction (≈30-60%) of primary production may pass through meiofauna. During winter, meiofaunal grazing is a less important link in the shallow zone, but at sublittoral depths, algal productivity may be limiting, and meiofauna depend on other food sources, such as bacteria and

  11. Methane Adsorption Study Using Activated Carbon Fiber and Coal Based Activated Carbon

    Institute of Scientific and Technical Information of China (English)

    Guo Deyong; Li Fei; Liu Wenge

    2013-01-01

    Inlfuence of ammonium salt treatment and alkali treatment of the coal based activated carbon (AC) and activated carbon ifber (ACF) adsorbents on methane adsorption capacity was studied via high-pressure adsorption experiment. Sur-face functional groups and pore structure of two types of adsorbents were characterized by the application of infrared ab-sorption spectroscopy (IR) and low temperature liquid nitrogen adsorption method. The results show that both ammonium salt treatment and alkali treatment have obvious effect on changing BET, pore volume as well as pore size distribution of adsorbents; and methane adsorption capacity of the activated carbon ifber is the maximum after the ammonium salt treatment.

  12. Using the Balanced Scorecard to Enhance Undergraduate Education in a First Year Business Course: A Pilot Study

    Science.gov (United States)

    Hunt, Irma; Taylor, Ronald K.; Winter, Anthony; Mackie, J. Jay; Fisher, Daniel

    2016-01-01

    Several research studies found that managers lacked a basic understanding of a balanced scorecard (BSC) approach to evaluate an organization. Because of this, the authors saw an opportunity to reorganize a course in order to provide students with an opportunity to address this issue. Therefore, a recent pilot study was conducted to ascertain…

  13. CORBA负载平衡的研究%Study on CORBA Load Balancing

    Institute of Scientific and Technical Information of China (English)

    骆志刚; 唐雪飞; 刘锦德

    2000-01-01

    CORBA is a widely accepted distributed computing specification,on which interoperability between heterogeneous computer platforms can be accomplished. The performance of CORBA-based appiication system is strongly dependent on object location and manual assignment of objects is impractial.In order to improve performance of CORBA-based distributed system,load-balancing problem must be considered. Firstly,two approaches that can be used tO design load-balanced CORBA application are discussed in detail. On that basis ,a general model of dynamic load balancing based on trading service is proposed. Not only load balancing is implemented in this model ,but also the extension of trading service is transparent to application developers and the original applications can be integrated with it without any modification. At the end,analysis of scalability of this model is given.

  14. Sustainability Management with the Sustainability Balanced Scorecard in SMEs: Findings from an Austrian Case Study

    Directory of Open Access Journals (Sweden)

    Susanna Falle

    2016-06-01

    Full Text Available Given the economic importance of small and medium sized enterprises (SMEs and their need for strategic sustainability management, this paper examines the concept of Sustainability Balanced Scorecard (SBSC with respect to SMEs. This case study describes the development of an SBSC in a middle-sized Austrian brewery. The existing methods used in SBSC creation were adapted to suit the company’s specific needs. The findings show that when developing an SBSC it is important to take specific SME characteristics into account and apply methods that allow for adaptation to the prevailing conditions, such as strategic management, organizational structure and resources. In the case study special attention was paid to strategy analysis and thereby the creation of a solid basis for the SBSC. Furthermore, the results show SBSC development is not a process of distinct consecutive steps, as it is often suggested in the literature, but rather that it is a complex process marked by iterative steps. Moreover, the paper highlights the supporting factors and challenges experienced. Whereas top management support, the presence of a project team and high employee involvement were identified as key supporting factors, a lack of specific resources and blurry strategy formulation exert negative influence on the development process. The results presented here should help other SMEs in their development of an SBSC. The paper stimulates scientific discourse on sustainability and strategic management by highlighting the relevant supporting factors and challenges.

  15. Implementasi Balanced scorecard pada Unit Usaha Kecil Menengah: Studi Kasus Sebuah Restoran di Jakarta

    OpenAIRE

    Dyah Lestari Widaningrum; Ivanaldy Kabul

    2014-01-01

    Increasing competition requires companies both large and small, to be more productive and innovative, therefore, companies need to be supported by an effective performance measurement system. In this research, the implementation of a balanced scorecard in SMEs engaged in the management of a restaurant, for a chance to be more superior and to compete amid the rapid development of the restaurant sector. Strategic map based on four perspective of Balanced Scorecard was defined, completed with ag...

  16. A simplified method for the assessment of carbon balance in agriculture: an application in organic and conventional micro-agroecosystems in a long-term experiment in Tuscany, Italy

    Directory of Open Access Journals (Sweden)

    Giulio Lazzerini

    2014-06-01

    Full Text Available Many research works propose sophisticated methods to analyse the carbon balance, while only a few tools are available for the calculation of both greenhouse gas emissions and carbon sequestration with simplified methods. This paper describes a carbon balance assessment conducted at farm level with a simplified methodology, which includes calculations of both CO2 emissions and carbon sequestration in crop rotations. This carbon balance was tested in the Montepaldi Long Term Experiment (MOLTE trial in central Italy, where two agroecosystems managed with two different farming practices (organic vs conventional are compared. Both in terms of CO2eq emissions and carbon sequestration, this simplified method applied in our experiment provided comparable results to those yielded by complex methodologies reported in the literature. With regard to the crop rotation scheme applied in the reference period (2003-2007, CO2 emissions from various farm inputs were found to be significantly lower (0.74 Mg ha-1 in the organically managed system than in the conventionally managed system (1.76 Mg ha-1. The same trend was observed in terms of CO2eq per unit of product (0.30 Mg kg-1 in the organic system and 0.78 Mg kg-1 in the conventional system. In the conventional system the sources that contributed most to total emissions were direct and indirect emissions associated with the use of fertilisers and diesel fuel. Also the stock of sequestered carbon was significantly higher in the organic system (27.9 Mg ha-1 of C than in the conventional system (24.5 Mg ha-1 of C. The carbon sequestration rate did not show any significant difference between the two systems. It will be necessary to test further this methodology also in commercial farms and to validate the indicators to monitor carbon fluxes at farm level.

  17. A study of legal attributes of carbon emission rights in carbon trading

    Institute of Scientific and Technical Information of China (English)

    Pei Qing; Jiang Dongmei; Zhang Mengheng

    2009-01-01

    Clean Development Mechanism (CDM) has given birth to an international carbon trading market prosperity,which provides developing countries with valuable opportunity to address climate change issues right along with economic development and environmental improvement to achieve sustainable development,However,most studies of CDM focus on economics,and few on its legal problems.CDM involves too many aspects.And the clear legal attribute of trading object is the basis of progress of the transaction and also the start point of legal protection.Therefore,this paper in accordance with the inherent principle of property rights economics,and environmental economics in CDM,only discusses CDM carbon emission right legal interpretation and its attribution.The paper recommends that in order to ensure and promote the carbon emission right trading,carbon emission right should be attributed into the system of real rights to be regulated by Real Right Law.In this way,carbon emission right can gain exclusive power of possession and use,which can achieve a clear right definition of environmental goods in line with Coase's theory to protect Chinese profit in carbon trading market and promote the development of the carbon trading market further.

  18. Potential of forest management to reduce French carbon emissions - regional modelling of the French forest carbon balance from the forest to the wood.

    Science.gov (United States)

    Valade, A.; Luyssaert, S.; Bellassen, V.; Vallet, P.

    2015-12-01

    In France the low levels of forest harvest (40 Mm3 per year over a volume increment of 89Mm3) is frequently cited to push for a more intensive management of the forest that would help reducing CO2 emissions. This reasoning overlooks the medium-to-long-term effects on the carbon uptake at the national scale that result from changes in the forest's structure and delayed emissions from products decay and bioenergy burning, both determinant for the overall C fluxes between the biosphere and the atmosphere. To address the impacts of an increase in harvest removal on biosphere-atmosphere carbon fluxes at national scale, we build a consistent regional modeling framework to integrate the forest-carbon system from photosynthesis to wood uses. We aim at bridging the gap between regional ecosystem modeling and land managers' considerations, to assess the synergistic and antagonistic effects of management strategies over C-based forest services: C-sequestration, energy and material provision, fossil fuel substitution. For this, we built on inventory data to develop a spatial forest growth simulator and design a novel method for diagnosing the current level of management based on stand characteristics (density, quadratic mean diameter or exploitability). The growth and harvest simulated are then processed with a life cycle analysis to account for wood transformation and uses. Three scenarii describe increases in biomass removals either driven by energy production target (set based on national prospective with a lock on minimum harvest diameters) or by changes in management practices (shorter or longer rotations, management of currently unmanaged forests) to be compared with business as usual simulations. Our management levels' diagnostics quantifies undermanagement at national scale and evidences the large weight of ownership-based undermanagement with an average of 26% of the national forest (between 10% and 40% per species) and thus represents a huge potential wood resource

  19. Studies to label Alfentanil with carbon-11

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, A.L. (Forschungzentrum Juelich GmbH (Germany). Inst. fuer Chemie I)

    1992-09-01

    Methodology applicable to the synthesis of no-carrier-added (O-methyl-{sup 11}C)alfentanil was developed. The sequence consisted of ({sup 11}C)methylation and propionylation of N-aryl-4-(hydroxymethyl)-4-(N-anilino)-piperidines 1a and 1c, followed by the chemoselective hydrolysis of bulk byproducts to facilitate isolation of the NCA carbon-11-labeled product by prep-HPLC. All three steps could be performed without isolation of intermediates in a single reaction vessel. (author).

  20. Ozone Removal by Filters Containing Activated Carbon: A Pilot Study

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William; Spears, Mike; Sullivan, Douglas; Mendell, Mark

    2009-09-01

    This study evaluated the ozone removal performance of moderate-cost particle filters containing activated carbon when installed in a commercial building heating, ventilating, and air conditioning (HVAC) system. Filters containing 300 g of activated carbon per 0.09 m2 of filter face area were installed in two 'experimental' filter banks within an office building located in Sacramento, CA. The ozone removal performance of the filters was assessed through periodic measurements of ozone concentrations in the air upstream and downstream of the filters. Ozone concentrations were also measured upstream and downstream of a 'reference' filter bank containing filters without any activated carbon. The filter banks with prefilters containing activated carbon were removing 60percent to 70percent of the ozone 67 and 81 days after filter installation. In contrast, there was negligible ozone removal by the reference filter bank without activated carbon.

  1. Combining pathway analysis with flux balance analysis for the comprehensive study of metabolic systems.

    Science.gov (United States)

    Schilling, C H; Edwards, J S; Letscher, D; Palsson, B Ø

    The elucidation of organism-scale metabolic networks necessitates the development of integrative methods to analyze and interpret the systemic properties of cellular metabolism. A shift in emphasis from single metabolic reactions to systemically defined pathways is one consequence of such an integrative analysis of metabolic systems. The constraints of systemic stoichiometry, and limited thermodynamics have led to the definition of the flux space within the context of convex analysis. The flux space of the metabolic system, containing all allowable flux distributions, is constrained to a convex polyhedral cone in a high-dimensional space. From metabolic pathway analysis, the edges of the high-dimensional flux cone are vectors that correspond to systemically defined "extreme pathways" spanning the capabilities of the system. The addition of maximum flux capacities of individual metabolic reactions serves to further constrain the flux space and has led to the development of flux balance analysis using linear optimization to calculate optimal flux distributions. Here we provide the precise theoretical connections between pathway analysis and flux balance analysis allowing for their combined application to study integrated metabolic function. Shifts in metabolic behavior are calculated using linear optimization and are then interpreted using the extreme pathways to demonstrate the concept of pathway utilization. Changes to the reaction network, such as the removal of a reaction, can lead to the generation of suboptimal phenotypes that can be directly attributed to the loss of pathway function and capabilities. Optimal growth phenotypes are calculated as a function of environmental variables, such as the availability of substrate and oxygen, leading to the definition of phenotypic phase planes. It is illustrated how optimality properties of the computed flux distributions can be interpreted in terms of the extreme pathways. Together these developments are applied to an

  2. Review of Study on Development Low Carbon Industry

    Institute of Scientific and Technical Information of China (English)

    Han; LIU; Zuwen; CAO

    2013-01-01

    Through collecting and arranging research findings in recent years,connotation,necessity,power mechanism,support system and foreign experience and implications of low carbon industry are reviewed and discussed. It is believed that future study should continue to follow up foreign latest research findings. In addition,it should attach importance and strengthen study on economic performance,system and technical management of low carbon industry.

  3. Assessment Of Carbon Leakage In Multiple Carbon-Sink Projects: ACase Study In Jambi Province, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Boer, Rizaldi; Wasrin, Upik R.; Hendri, Perdinan; Dasanto,Bambang D.; Makundi, Willy; Hero, Julius; Ridwan, M.; Masripatin, Nur

    2007-06-01

    Rehabilitation of degraded forest land throughimplementation of carbon sink projects can increase terrestrial carbonstock. However, carbon emissions outside the project boundary, which iscommonly referred to as leakage, may reduce or negate the sequestrationbenefits. This study assessed leakage from carbon sink projects thatcould potentially be implemented in the study area comprised of elevensub-districts in the Batanghari District, Jambi Province, Sumatra,Indonesia. The study estimates the probability of a given land use/coverbeing converted into other uses/cover, by applying a logit model. Thepredictor variables were: proximity to the center of the land use area,distance to transportation channel (road or river), area of agriculturalland, unemployment (number of job seekers), job opportunities, populationdensity and income. Leakage was estimated by analyzing with and withoutcarbon sink projects scenarios. Most of the predictors were estimated asbeing significant in their contribution to land use cover change. Theresults of the analysis show that leakage in the study area can be largeenough to more than offset the project's carbon sequestration benefitsduring the period 2002-2012. However, leakage results are very sensitiveto changes of carbon density of the land uses in the study area. Byreducing C-density of lowland and hill forest by about 10 percent for thebaseline scenario, the leakage becomes positive. Further data collectionand refinement is therefore required. Nevertheless, this study hasdemonstrated that regional analysis is a useful approach to assessleakage.

  4. Experimental study on working parameters of earth pressure balance shield machine tunneling in soft ground

    Institute of Scientific and Technical Information of China (English)

    Hehua ZHU; Shaoming LIAO; Qianwei XU; Qizhen ZHENG

    2008-01-01

    Deep sedimentary deposits of soft clays are widely distributed in coastal areas as well as many interior major cities in China. In order to study the stratum adapt-ability of earth pressure balance (EPB) shield machine tunneling in such types of soft ground, model tests of tunneling excavation, using the running tunnel of the Shanghai Metro Line M8 as a background, are carried out with different over burden ratios, opening rates of cutter head, driving speeds and rotation speeds of screw conveyor. Based on the test results, the interrelationships between chamber pressure and mucking efficiency, muck-ing rate and driving speed, thrust force and torque are obtained. The influences of tunnel depth, opening rate of cutter head and driving speed on thrust force and tor-que are revealed. Such findings can not only facilitate establishing relationships between shield working para-meters and soil properties, but also serve as a guide for the design and construction of shield tunnel in soft ground.

  5. New aspects of poly aniline doping: A study based on using electrochemical quartz crystal nano balance

    International Nuclear Information System (INIS)

    Oxidative and non-oxidative dopings of poly aniline different concentrations have been studied by electrochemical quartz crystal nano balance technique. Poly aniline was synthesized electrochemically on the gold electrode of quartz crystal using a galvanostatic electro polymerization method (1 ma/c m2). Electrochemically synthesized poly aniline film was exposed to different concentrations of various acidic solutions and the changes in the mass (frequency) of the polymer were recorded. Results showed that the extent and the rate of non-oxidative doping depend on the concentration and nature of dopant acid. The rate of doping in the case of a number of tested inorganic acids was as the order of: H3PO442SO4. Exposure of doped poly aniline to ammonia solution (0.5 M) resulted a mass reduction in the polymer film due to the non-oxidative un doping process. Further experiments showed that this doping/un doping behaviour is a completely reversible process. Mass changes of the polymer in oxidative doping/un doping process were also recorded. It was also found that at ph values lower than 1, the total mass change during oxidation of the polymer was dependent on acid (or proton) concentration. However, at ph values over 1, the mass change during oxidation was independent of acid (or proton) concentration. These two observations support two different mechanisms of doping suggested by other workers

  6. Transcription closed and open complex dynamics studies reveal balance between genetic determinants and co-factors.

    Science.gov (United States)

    Sala, Adrien; Shoaib, Muhammad; Anufrieva, Olga; Mutharasu, Gnanavel; Jahan Hoque, Rawnak; Yli-Harja, Olli; Kandhavelu, Meenakshisundaram

    2015-05-19

    In E. coli, promoter closed and open complexes are key steps in transcription initiation, where magnesium-dependent RNA polymerase catalyzes RNA synthesis. However, the exact mechanism of initiation remains to be fully elucidated. Here, using single mRNA detection and dual reporter studies, we show that increased intracellular magnesium concentration affects Plac initiation complex formation resulting in a highly dynamic process over the cell growth phases. Mg2+ regulates transcription transition, which modulates bimodality of mRNA distribution in the exponential phase. We reveal that Mg2+ regulates the size and frequency of the mRNA burst by changing the open complex duration. Moreover, increasing magnesium concentration leads to higher intrinsic and extrinsic noise in the exponential phase. RNAP-Mg2+ interaction simulation reveals critical movements creating a shorter contact distance between aspartic acid residues and Nucleotide Triphosphate residues and increasing electrostatic charges in the active site. Our findings provide unique biophysical insights into the balanced mechanism of genetic determinants and magnesium ion in transcription initiation regulation during cell growth.

  7. A theoretical study of a carbon lattice system for lithium intercalated carbon anodes

    Energy Technology Data Exchange (ETDEWEB)

    Scanlon, L.G.; Storch, D.M.; Newton, J.H. [Wright Lab., Wright-Patterson Air Force Base, OH (United States); Sandi, G. [Argonne National Lab., IL (United States)

    1997-09-01

    A theoretical study was performed using computational chemistry to describe the intermolecular forces between graphite layers as well as spacing and conformation. It was found that electron correlation and a diffuse basis set were important for this calculation. In addition, the high reactivity of edge sites in lithium intercalated carbon anodes was also investigated. In this case, the reactive sites appear to strongly correlate with the relative distribution of the total atomic spin densities as well as total atomic charges. The spacing of graphite layers and lithium ion separation within an {open_quotes}approximated{close_quotes} lithium intercalated carbon anode was also investigated. The spacing of the carbon layers used in this investigation agrees most closely for that found in disordered carbon lattices.

  8. Irradiation of carbon nanotubes with carbon projectiles: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Denton, Cristian D. [Departamento de Fisica Aplicada, Universidad de Alicante, 03080 Alicante (Spain); Heredia-Avalos, Santiago; Moreno-Marin, Juan Carlos [Departamento de Fisica, Ingenieria de Sistemas y Teoria de la Senal, Universidad de Alicante, 03080 Alicante (Spain)

    2013-04-15

    The irradiation of carbon based nanostructures with ions and electrons has been shown to be an appropriate tool to tailor their properties. The defects induced in the nanostructures during irradiation are able to modify their mechanical and electronic properties. Here we simulate the irradiation of carbon nanotubes with carbon ions using a molecular dynamics code. We use the Tersoff potential joined smoothly to the Universal Ziegler-Biersack-Littmark potential at short distances. We study the number of defects produced after irradiation with a single carbon ion finding a saturation with its energy at {proportional_to} 3 keV. We observe, after continuum irradiation with low energy ions, the formation of bumps in the irradiated region. For larger energy ions we find that the diameter of the nanotube shrinks as shown in previous works. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Mass balance of the Greenland ice sheet - a study of ICESat data, surface density and firn compaction modelling

    DEFF Research Database (Denmark)

    Sørensen, L. S.; Simonsen, Sebastian Bjerregaard; Nielsen, K.;

    2010-01-01

    ICESat has provided surface elevation measurements of the ice sheets since the launch in January 2003, resulting in a unique data set for monitoring the changes of the cryosphere. Here we present a novel method for determining the mass balance of the Greenland ice sheet derived from ICESat...... in estimating the mass balance of the Greenland ice sheet. We find firn dynamics and surface densities to be important factors in deriving the mass loss from remote sensing altimetry. The volume change derived from ICESat data is corrected for firn compaction, vertical bedrock movement and an intercampaign...... boundary conditions. We find an annual mass loss of the Greenland ice sheet of 210 ± 21 Gt yr-1 in the period from October 2003 to March 2008. This result is in good agreement with other studies of the Greenland ice sheet mass balance, based on different remote sensing techniques....

  10. Remote Sensing Survey of Grassland Resources and Study of Grass-livestock Balance in Hangjin Banner of Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    Terigele; Yanhong; XU; Ying; LI; Quan; WU

    2015-01-01

    The data of this paper mainly include statistics,field survey data and MODIS remote sensing image data. This paper estimates the aboveground biomass of grassland and theoretical livestock carrying capacity of natural grassland in Hangjin Banner and draws a grass- livestock balance table in accordance with the actual and theoretical livestock carrying capacity of natural grassland. Studies have shown that the grass and livestock balance is good in Hangjin Banner,and the overloading rate is 1. 5%; there was no overloading in 2010 and 2011.

  11. Including Complexity, Heterogeneity and Vegetation Response Characteristics into Carbon Balance Assessments at Continental Scale: Stepwise Development of a Simulation Framework with the Bottom-Up Core Model PIXGRO

    Science.gov (United States)

    Tenhunen, J.; Geyer, R.; Owen, K.; Falge, E.; Reichstein, M.

    2005-12-01

    The cultural landscapes of the European continent are characterized by highly fragmented land cover, distributed along the gradient from extremely sparse, dry Mediterranean shrublands to sub-arctic wetlands and forests. In addition, several mountain systems, in particular the Alps, modify vegetation and land surface exchange characteristics. In the recently begun CARBOEUROPE project, energy, water and CO2 exchanges of selected ecosystem types are monitored via eddy covariance methods. The model PIXGRO is being developed to help relate measurements at flux tower sites to measurements carried out at larger scale and to CO2 exchange estimates obtained with atmospheric inversion techniques. The main question addressed in this modelling effort is how to efficiently include a spectrum of vegetation characteristics into carbon balance assessments at large scale and in such a way that the influence of local response on regional fluxes may be visualized and analyzed. Furthermore, the modelling attempts to demonstrate both strengths and weaknesses in existing ecosystem process information required to understand carbon balances. The model PIXGRO attempts to define continental distribution and controls on net ecosystem CO2 exchange for ca. 12 ecosystem types, including coniferous forest, deciduous forest, grassland, cropland (assumed dominated by grain crops), northern boreal mixed forest, tundra, wetlands, alpine forest, evergreen forest, evergreen shrubland, and Mediterranean oak woodland. The model uses a single layer canopy with two leaf classes (sun and shade) and a three layered rooting zone to estimate GPP, ecosystem respiration and overall ecosystem gas exchange. Maximum LAI is determined during each year from the MODIS LAI-product. In the case of grassland, crops, tundra and wetlands, classical growth routines estimate dynamic changes in the vegetation canopy. Soil/canopy coupling in response to drought reflects a root system hormonal signalling and is calibrated with

  12. New Demands, New Supplies: A National Look at the Water Balance of Carbon Dioxide Capture and Sequestration

    Science.gov (United States)

    Roach, J. D.; Kobos, P.; Klise, G. T.; Krumhansl, J. L.; McNemar, A.

    2010-12-01

    Concerns over rising concentrations of greenhouse gases in the atmosphere have resulted in serious consideration of policies aimed at reduction of anthropogenic carbon dioxide (CO2) emissions. If large scale abatement efforts are undertaken, one critical tool will be geologic sequestration of CO2 captured from large point sources, specifically coal and natural gas fired power plants. Current CO2 capture technologies exact a substantial energy penalty on the source power plant, which must be offset with make-up power. Water demands increase at the source plant due to added cooling loads. In addition, new water demand is created by water requirements associated with generation of the make-up power. At the sequestration site however, saline water may be extracted to manage CO2 plum migration and pressure build up in the geologic formation. Thus, while CO2 capture creates new water demands, CO2 sequestration has the potential to create new supplies. Some or all of the added demand may be offset by treatment and use of the saline waters extracted from geologic formations during CO2 sequestration. Sandia National Laboratories, with guidance and support from the National Energy Technology Laboratory, is creating a model to evaluate the potential for a combined approach to saline formations, as a sink for CO2 and a source for saline waters that can be treated and beneficially reused to serve power plant water demands. This presentation will focus on the magnitude of added U.S. power plant water demand under different CO2 emissions reduction scenarios, and the portion of added demand that might be offset by saline waters extracted during the CO2 sequestration process. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

  13. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L. Biochar and Feasibility for Carbon Capture and Energy Balance.

    Directory of Open Access Journals (Sweden)

    Muhammad Khalid Rafiq

    Full Text Available This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13. Higher heating value (HHV of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13 demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario.

  14. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance.

    Science.gov (United States)

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario.

  15. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance.

    Science.gov (United States)

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario. PMID:27327870

  16. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance

    Science.gov (United States)

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario. PMID:27327870

  17. Comparative study of solvent properties for carbon dioxide absorption

    Energy Technology Data Exchange (ETDEWEB)

    Aschenbrenner, O.; Styring, P. [University of Sheffield, Sheffield (United Kingdom)

    2010-07-01

    Several inexpensive and non-toxic solvents with low vapour pressures were investigated for their suitability as alternative solvents for the absorption of carbon dioxide from flue gas. The solvents include poly(ethylene glycol)s, poly(ethylene glycol) ethers, poly(ethylenimine) and glycerol-based substances. Solvent properties such as thermal stability, solubility of carbon dioxide and selectivity over nitrogen were investigated in a systematic study using a thermogravimetric analyser. Absorption results are reported for pure carbon dioxide and nitrogen as well as a mixture of both gases. Desorption and long-term sorption behaviour are also discussed. Glycerol and poly(ethylene glycol)s show a high solubility of carbon dioxide. Due to the high viscosity of the solvent, carbon dioxide absorption in poly(ethylenimine) is very slow in spite of the presence of favourable amine groups. PEG 300 was found to be the best solvent in this study and shows a high carbon dioxide solubility as well as good selectivity over nitrogen. The advantages of high stability, low solvent loss and low desorption energy of PEG 300 may outweigh its lower absorption capacity compared to the state-of-the-art solvent monoethanolamine, making it a potentially advantageous solvent for industrial carbon dioxide absorption processes.

  18. Fully-compliant statically-balanced mechanisms without prestressing assembly: concepts and case studies

    Directory of Open Access Journals (Sweden)

    G. Chen

    2011-08-01

    Full Text Available The purpose of this paper is to present new concepts for designing fully-compliant statically-balanced mechanisms without prestressing assembly. A statically-balanced compliant mechanism can ideally provide zero stiffness and energy free motion like a traditional rigid-body mechanism. These characteristics are important in design of compliant mechanisms where low actuation force, accurate force transmission or high-fidelity force feedback are primary concerns. Typically, static balancing of compliant mechanisms has been achieved by means of prestressing assembly. However, this can often lead to creep and stress relaxation arising in the flexible members. In this paper two concepts are presented which eliminate the need for prestressing assembly of compliant mechanisms: (1 a weight compensator which employs a constant-force compliant mechanism, (2 a near-zero-stiffness mechanism which combines two multistable mechanisms. In addition to the advantages provided by statically-balanced compliant mechanisms, two other notable features of these statically-balanced mechanisms are their ability to be monolithically fabricated and to return to their as-fabricated position without any disassembly when not in use.

  19. Lake Michigan Mass Balance Study Post Audit: Integrated, Multi-media PCB Modeling and Forecasting for Lake Trout

    Science.gov (United States)

    The Lake Michigan (LM) Mass Balance Study was conducted to measure and model polychlorinated biphenyls (PCBs) and other anthropogenic substances to gain a better understanding of the transport, fate, and effects of these substances within the system and to aid managers in the env...

  20. Study on organosilicon plasma polymers implanted by carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Radeva, E; Yourukova, L; Kolentsov, K; Balabanov, S; Zhechev, D; Steflekova, V [Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Amov, B [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria)], E-mail: eradeva@issp.bas.bg

    2008-05-01

    In the present work plasma polymer films obtained from hexamethyldisiloxane have been implanted by carbon ions at three different doses. The photoluminescent properties of the implanted polymers were investigated. The optical transmission of these polymer layers was investigated in the visible spectral region. Their electrical parameters were also measured. It was found that the resulting changes do not worsen the protective properties of the implanted polymer layer. The variations in the properties studied might be ascribed to the nanostructured carbon clusters formed on the polymer surface. The results obtained could form the basis for further optimization of the polymer structure by carbon ion implantation in view of applications in electroluminescent display structures.

  1. Studies relevant to the catalytic activation of carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Ford, P.C.

    1992-06-04

    Research activity during the 1991--1992 funding period has been concerned with the following topics relevant to carbon monoxide activation. (1) Exploratory studies of water gas shift catalysts heterogenized on polystyrene based polymers. (2) Mechanistic investigation of the nucleophilic activation of CO in metal carbonyl clusters. (3) Application of fast reaction techniques to prepare and to investigate reactive organometallic intermediates relevant to the activation of hydrocarbons toward carbonylation and to the formation of carbon-carbon bonds via the migratory insertion of CO into metal alkyl bonds.

  2. Understanding the context of balanced scorecard implementation: a hospital-based case study in pakistan

    Science.gov (United States)

    2011-01-01

    Background As a response to a changing operating environment, healthcare administrators are implementing modern management tools in their organizations. The balanced scorecard (BSC) is considered a viable tool in high-income countries to improve hospital performance. The BSC has not been applied to hospital settings in low-income countries nor has the context for implementation been examined. This study explored contextual perspectives in relation to BSC implementation in a Pakistani hospital. Methods Four clinical units of this hospital were involved in the BSC implementation based on their willingness to participate. Implementation included sensitization of units towards the BSC, developing specialty specific BSCs and reporting of performance based on the BSC during administrative meetings. Pettigrew and Whipp's context (why), process (how) and content (what) framework of strategic change was used to guide data collection and analysis. Data collection methods included quantitative tools (a validated culture assessment questionnaire) and qualitative approaches including key informant interviews and participant observation. Results Method triangulation provided common and contrasting results between the four units. A participatory culture, supportive leadership, financial and non-financial incentives, the presentation of clear direction by integrating support for the BSC in policies, resources, and routine activities emerged as desirable attributes for BSC implementation. The two units that lagged behind were more involved in direct inpatient care and carried a considerable clinical workload. Role clarification and consensus about the purpose and benefits of the BSC were noted as key strategies for overcoming implementation challenges in two clinical units that were relatively ahead in BSC implementation. It was noted that, rather than seeking to replace existing information systems, initiatives such as the BSC could be readily adopted if they are built on existing

  3. Implementasi Balanced scorecard pada Unit Usaha Kecil Menengah: Studi Kasus Sebuah Restoran di Jakarta

    Directory of Open Access Journals (Sweden)

    Dyah Lestari Widaningrum

    2014-12-01

    Full Text Available Increasing competition requires companies both large and small, to be more productive and innovative, therefore, companies need to be supported by an effective performance measurement system. In this research, the implementation of a balanced scorecard in SMEs engaged in the management of a restaurant, for a chance to be more superior and to compete amid the rapid development of the restaurant sector. Strategic map based on four perspective of Balanced Scorecard was defined, completed with agreement of strategic objective and measurement. This implementation give evidence that even with many limitations on SMEs, they have developed balanced scorecard, with adjustment based on condition for strategic objective performance indicator, so this performance measurement evaluation process is applicable and able to achieve the main objective, to provide information for continuous improvement process.

  4. Design Strategies for Balancing Exertion Games: A Study of Three Approaches

    DEFF Research Database (Denmark)

    Jensen, Mads Møller; Grønbæk, Kaj

    2016-01-01

    In sports, if players' physical and technical abilities are mismatched, the competition is often uninteresting for them. With the emergence of exertion games, this could be changing. Player balancing, known from video games, allows players with different skill levels to compete, however, it is un......In sports, if players' physical and technical abilities are mismatched, the competition is often uninteresting for them. With the emergence of exertion games, this could be changing. Player balancing, known from video games, allows players with different skill levels to compete, however...... these three approaches is used to investigate the qualities and challenges within each approach and explore how the player experience is affected by them. Based on these findings, we suggest four design strategies for balancing exertion games, so that players will stay engaged in the game and contain...... the feeling of a fair competition, even if they have mismatched skills....

  5. Association of gait and balance disorders with age-related white matter changes: the LADIS study

    DEFF Research Database (Denmark)

    Baezner, H.; Blahak, C.; Poggesi, A.;

    2008-01-01

    . Quantitative tests of gait and balance include the Short Physical Performance Battery (SPPB; range: 0 [poor] to 12 [normal]), a timed 8-m walk, and a timed single leg stance test. RESULTS: In cross-sectional analysis, deficiencies in gait and balance performance were correlated with the severity of ARWMC (SPPB...... on different objective measures of gait and balance. METHODS: Six hundred thirty-nine nondisabled individuals were prospectively enrolled and are being followed-up for 3 years. Subjects are graded in three standardized categories of ARWMC (mild, moderate, and severe) according to central MRI reading......% CI 1.02 to 2.52; severe vs mild ARWMC: odds ratio 1.75, 95% CI 1.09 to 2.80). CONCLUSIONS: Our findings support a strong association between the severity of age-related white matter changes and the severity of gait and motor compromise. Physical activity might have the potential to reduce the risk...

  6. Social Studies Education as a Tool for Checks and Balances to Political Irregularities and Franchise in Nigeria

    Directory of Open Access Journals (Sweden)

    Okogu, J. O.

    2015-08-01

    Full Text Available This study examines social studies education as a tool for checks and balances to political irregularities and franchise in Nigeria. The aim is to explore how social studies education can be used in correcting political irregularities in exercising franchise in Nigeria. Social studies education is concerned with citizenship education which entails a complex process of inculcating societal norms, morals, knowledge, skills and values that serve as checks and balances to political irregularities and franchise. Based on this premise, social studies education emphasizes the acquisition of the relevant skills, knowledge, values and beliefs and other capabilities that are significant in conformity with the checking of political irregularities as been observed in exercising political franchise. Social studies education is transformative in contents, objectives and accommodates contemporary issues, social issues, environmental issues, and most especially political matters for the purposes of re-organizing political structure in society.

  7. TEM and EELS study of deuterated carbon: application to the fuel retention in tokamaks; Etude couplee MET-EELS du carbone deutere: application a la retention du combustible dans les tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Bernier, N

    2007-12-15

    We developed a methodology, based on the combination of TEM and EELS techniques, for a structural and chemical characterization, at a high spatial resolution, of a wide range of carbon materials. We i) optimized, in the framework of theoretical models, the sp2 fraction quantification from pure carbons by EELS ii) transferred this quantification to deuterated amorphous carbon layers iii) showed, from graphitized carbons, how the TEM-EELS combination allows to detect low concentrations of implanted D. Due to the accomplishment of these developments, we applied our approach to the study of D retention in composites C/C, which are the plasma-facing materials in TS. We showed that specific localized retention sites correspond to relatively large ({approx} 3 mm.) cracks between fibres and matrix; such cracks offer a simple and direct path for deuterated amorphous carbon. The particle balance performed in TS is discussed in the light of this trapping mechanism. (author)

  8. Tropical forest carbon balance: effects of field- and satellite-based mortality regimes on the dynamics and the spatial structure of Central Amazon forest biomass

    International Nuclear Information System (INIS)

    Debate continues over the adequacy of existing field plots to sufficiently capture Amazon forest dynamics to estimate regional forest carbon balance. Tree mortality dynamics are particularly uncertain due to the difficulty of observing large, infrequent disturbances. A recent paper (Chambers et al 2013 Proc. Natl Acad. Sci. 110 3949–54) reported that Central Amazon plots missed 9–17% of tree mortality, and here we address ‘why’ by elucidating two distinct mortality components: (1) variation in annual landscape-scale average mortality and (2) the frequency distribution of the size of clustered mortality events. Using a stochastic-empirical tree growth model we show that a power law distribution of event size (based on merged plot and satellite data) is required to generate spatial clustering of mortality that is consistent with forest gap observations. We conclude that existing plots do not sufficiently capture losses because their placement, size, and longevity assume spatially random mortality, while mortality is actually distributed among differently sized events (clusters of dead trees) that determine the spatial structure of forest canopies. (paper)

  9. Energy Balance Feasibility Study for Latinas in Texas: A Qualitative Assessment

    Directory of Open Access Journals (Sweden)

    Amelie G. Ramirez, DrPH

    2007-10-01

    Full Text Available IntroductionObesity has reached epidemic levels, with nearly two-thirds of the U.S. population considered overweight or obese. Latinos have some of the highest rates of overweight, obesity, and sedentary lifestyle. Research from scientifically sound evidence-based interventions to reduce the disproportionate burden of obesity and its associated morbidity and mortality among Latinas is greatly needed. The purpose of this study was to assess knowledge, attitudes, and behaviors about nutrition and exercise among Latinas aged 40 years and older residing in a low-income community in Houston, Texas, and the applicability of an evidence-based church program to promote healthy energy balance.MethodsQualitative assessment was conducted through 10 focus groups with 75 women recruited through three Catholic churches, community groups, and leaders.ResultsParticipants identified barriers and enabling factors to healthy nutrition and physical activity. Barriers included lack of awareness about nutrition and physical activity, cultural beliefs, and socioeconomic and environmental factors. Preferred strategies were group activities with direct guidance from qualified individuals and interpersonal contact among participants, social support with positive reinforcement for behavior change or maintenance, and a friendly environment for learning and achieving suitable goals. The church was considered a powerful resource to influence Latinas to improve their health, exercise, and nutrition practices.ConclusionOur findings suggest that using the church environment to reach Latina women aged 40 years and older is a feasible and culturally appropriate strategy. The church environment provides a safe, comfortable, and familiar atmosphere for women and addresses specific cultural barriers and safety concerns of family members.

  10. Water and nutrient balances in a large tile-drained agricultural catchment: a distributed modeling study

    Directory of Open Access Journals (Sweden)

    H. Li

    2010-11-01

    Full Text Available This paper presents the development and implementation of a distributed model of coupled water nutrient processes, based on the representative elementary watershed (REW approach, to the Upper Sangamon River Basin, a large, tile-drained agricultural basin located in central Illinois, mid-west of USA. Comparison of model predictions with the observed hydrological and biogeochemical data, as well as regional estimates from literature studies, shows that the model is capable of capturing the dynamics of water, sediment and nutrient cycles reasonably well. The model is then used as a tool to gain insights into the physical and chemical processes underlying the inter- and intra-annual variability of water and nutrient balances. Model predictions show that about 80% of annual runoff is contributed by tile drainage, while the remainder comes from surface runoff (mainly saturation excess flow and subsurface runoff. It is also found that, at the annual scale nitrogen storage in the soil is depleted during wet years, and is supplemented during dry years. This carryover of nitrogen storage from dry year to wet year is mainly caused by the lateral loading of nitrate. Phosphorus storage, on the other hand, is not affected much by wet/dry conditions simply because the leaching of it is very minor compared to the other mechanisms taking phosphorous out of the basin, such as crop harvest. The analysis then turned to the movement of nitrate with runoff. Model results suggested that nitrate loading from hillslope into the channel is preferentially carried by tile drainage. Once in the stream it is then subject to in-stream denitrification, the significant spatio-temporal variability of which can be related to the variation of the hydrologic and hydraulic conditions across the river network.

  11. A study of the surface energy balance on slopes in a tallgrass prairie

    Science.gov (United States)

    Nie, D.; Demetriades-Shah, T.; Kanemasu, E. T.

    1990-01-01

    Four slopes (north, south, east, and west) were selected on the Konza Prairie Research Natural Area to study the effect of topography on surface energy balance and other micrometeorological variables. Energy fluxes, air temperature, and vapor pressure were measured on the sloped throughout the 1988 growing season. Net radiation was the highest on the south-facing slope and lowest on the north-facing slope, and the difference was more than 150 W/sq m (20 to 30 percent) at solar noon. For daily averages, the difference was 25 W/sq m (15 percent) early in the season and increased to 60 W/sq m (30 to 50 percent) in September. The east-facing and west-facing slopes had the same daily average net radiation, but the time of day when maximum net radiation occurred was one hour earlier for the east-facing slope and one hour later for the west-facing slope relative to solar noon. Soil heat fluxes were similar for all the slopes. The absolute values of sensible heat flux (h) was consistently lower on the north-facing slope compared with other slopes. Typical difference in the values of H between the north-facing and the south-facing slopes was 15 to 30 W/sq m. The south-facing slope had the greatest day to day fluctuation in latent heat flux as a result of interaction of net radiation, soil moisture, and green leaf area. The north-facing slope had higher air temperatures during the day and higher vapor pressures both during the day and at night when the wind was from the south.

  12. Study of neutron rich carbon isotopes

    Science.gov (United States)

    Fallon, Paul

    2012-03-01

    Electric quadrupole (E2) matrix elements are important quantities in nuclear structure. In particular they are sensitive to nuclear deformation, the decoupling of proton and neutron degrees of freedom, and are often affected by small components of the nuclear wave function. Neutron-rich carbon isotopes have attracted a great deal of attention recently, both experimentally and theoretically, with regards to the question of spatially extended (halo-like) and decoupled valence neutrons. For example, 19C and the drip-line nucleus 22C are proposed to have ground-state neutron halo structures. Electric quadrupole transition rates in 16C 18C and 20C are among the lowest found throughout the nuclear chart and this fact has been cited by some as evidence for a reduced coupling between the valence neutrons and the core nucleons. In this talk I will present the results from our experiments to measure the transition rates in 16,18,20C and discuss the evidence for a ``decoupling'' of valence neutrons from the core that goes beyond the usual shell model approach. Data will be compared to shell model and no-core (ab-initio) shell model calculations with NN and NN+NNN interactions.

  13. 西藏高原地区陆地生态系统碳素循环平衡模拟%Simulation of terrestrial carbon cycle balance model in Tibet

    Institute of Scientific and Technical Information of China (English)

    王建林; 胡单; 孙自保

    2003-01-01

    Based on climate material, the simplified terrestrial carbon cycle balance (TCCB) modelwas established, which is semi-mechanism and semi-statistics. Through TCCB model, our estimateindicates that the southeastern part of the Tibetan Plateau has much higher carbon content, and wehave calculated the litter carbon pool, NPP, carbon fluxes and described their spatial characteristicsin this region. Based on the TCCB model simulation, NPP in Tibet is 1.73 × 108 tC/a, soil organicinput rate is 0.66 × 108 tC/a, litter mineralization rate is 1.07 × 108 tC/a, vegetation litterfall rate is1.73 × 108 tC/a, the litter carbon pool is 7.26 × l08 tC, and soil decomposition rate is 309.54 × 108tC/a. The carbon budget was also analyzed based on the estimates of carbon pool and fluxes. Thespatial distributions of carbon pools and carbon fluxes in different compartments of terrestrialecosystem were depicted with map respectively in Tibet. The distribution of NPP, vegetation litterfallrate, litter, litter mineralization rate, soil organic input rate and the soil decomposition rate wereabstracted with temperature, precipitation, fractional vegetation and land feature.

  14. Balancing Generalization and Lexical Conservatism: An Artificial Language Study with Child Learners

    Science.gov (United States)

    Wonnacott, Elizabeth

    2011-01-01

    Successful language acquisition involves generalization, but learners must balance this against the acquisition of lexical constraints. Such learning has been considered problematic for theories of acquisition: if learners generalize abstract patterns to new words, how do they learn lexically-based exceptions? One approach claims that learners use…

  15. The Digital Balance between Industrialised and Developing Countries: Futures Studies for Development

    Science.gov (United States)

    Hietanen, Olli

    2006-01-01

    The purpose of researching the digital balance between industrialised and developing countries was to discover how information and communication technology (ICT), content and e-services developed in Finland will work on the African continent, and vice versa. Globalisation and the associated new international division of labour and well-being…

  16. Study on Balanced Development of Industrialization,Urbanization and Agricultural Modernization in Henan Province

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    This article expounds the connotation of balanced development of " industrialization,urbanization and agricultural modernization",and points out the problems thwarting balanced development of " industrialization,urbanization and agricultural modernization" in Henan Province as follows:the level of industrialization is not high;the general level of urbanization is low;the agricultural foundation is weak and there are many institutional barriers.The goal of balanced development of " industrialization,urbanization and agricultural modernization" in Henan Province is to take a road of industrialization and urbanization,not at the expense of agriculture and food.Based on this,the measures are put forward for balanced development of " industrialization,urbanization and agricultural modernization " in Henan Province as follows:keep to the new road of industrialization with characteristics of Henan Province,promote the development of industry and accelerate the transformation of pattern;keep to the road of new urbanization with characteristics of Henan Province,and promote the rapid change in urban development pattern;adhere to the road of agricultural modernization with characteristics of Henan Province,and promote the rapid change in pattern of agricultural development.

  17. Geostrophic balance with a full Coriolis Force: implications for low latitutde studies

    Science.gov (United States)

    Juarez, M. de la Torre

    2002-01-01

    In its standard form, geostrophic balance uses a partial representation of the Coriolis force. The resulting formation has a singularity at the equator, and violates mass and momentum conservation. When the horizontal projection of the planetary rotation vector is considered, the singularity at the equator disappears, continuity can be preserved, and quasigeostrophy can be formulated at planetary scale.

  18. Bottom-up assessment of the Net Ecosystem Carbon Balance of Russian forests in 2010 for comparison to Top-down estimates.

    Science.gov (United States)

    Maksyutov, S. S.; Shvidenko, A.; Shchepashchenko, D.

    2014-12-01

    The verified full carbon assessment of Russian forests (FCA) is based on an Integrated Land Information System (ILIS) that includes a multi-layer and multi-scale GIS with basic resolution of 1 km and corresponding attributive databases. The ILIS aggregates all available information about ecosystems and landscapes, sets of empirical and semi-empirical data and aggregations, data of different inventories and surveys, and multi-sensor remote sensing data. The ILIS serves as an information base for application of the landscape-ecosystem approach (LEA) of the FCA and as a systems design for comparison and mutual constraints with other methods of study of carbon cycling of forest ecosystems (eddy covariance; process models; inverse modeling; and multi-sensor application of remote sensing). The LEA is based on a complimentary use of the flux-based method with some elements of the pool-based method. Introduction of climatic parameters of individual years in the LEA, as well as some process-based elements, allows providing a substantial decrease of the uncertainties of carbon cycling yearly indicators of forest ecosystems. Major carbon pools (live biomass, coarse woody debris, soil organic carbon) are estimated based on data on areas, distribution and major biometric characteristics of Russian forests presented in form of the ILIS for the country. The major fluxes accounted for include Net Primary Production (NPP), Soil Heterotrophic Respiration (SHR), as well as fluxes caused by decomposition of Coarse Woody Debris (CWD), harvest and use of forest products, fluxes caused by natural disturbances (fire, insect outbreaks, impacts of unfavorable environment) and lateral fluxes to hydrosphere and lithosphere. Use of landscape-ecosystem approach resulted in the NECB at 573±140 Tg C yr-1 (CI 0.9). While the total carbon sink is high, large forest areas, particularly on permafrost, serve as a carbon source. The ratio between net primary production and soil heterotrophic

  19. Reproducibility of Standing Posture for X-Ray Radiography: A Feasibility Study of the BalancAid with Healthy Young Subjects

    OpenAIRE

    Dewi, Dyah Ekashanti Octorina; Veldhuizen, Albert G.; Burgerhof, Johannes G.M.; Purnama, I Ketut Eddy; van Ooijen, Peter M. A.; Wilkinson, Michael H.F.; Mengko, Tati Latifah Erawati Rajab; Verkerke, Gijsbertus Jacob

    2010-01-01

    Unreliable spinal X-ray radiography measurement due to standing postural variability can be minimized by using positional supports. In this study, we introduce a balancing device, named BalancAid, to position the patients in a reproducible position during spinal X-ray radiography. This study aimed to investigate the performance of healthy young subjects’ standing posture on the BalancAid compared to standing on the ground mimicking the standard X-rays posture in producing a reproducible postu...

  20. Recommended ingestion of indispensable amino acids to young men . A study using stable isotopes, plasmatic amino acids and nitrogen balance

    International Nuclear Information System (INIS)

    It has been previously stated that the minimum physiological recommendations for the indispensable amino acids in health adults, as proposed by FAO/WHO/UNU in 1985, are far too low, except for the methionine. An amino acid stable isotopic kinetic study was conducted to seek further experimental support to this hypothesis. Twenty healthy young men received an l-amino acid based diet, supplying 140 mg N.kg-1.d-1, patterned on egg protein for 1 week, then for 3 weeks either i) a pattern based on current international recommendations (FAO diet, n=7), ii) a the tentative Laboratory of Human Nutrition of the Massachusetts Institute of Technology, new amino acid recommendation pattern (MIT diet, n=7) or iii) again the egg hen pattern (EGG diet, n=6). All subjects were again studied for one final, consecutive week of the egg diet. At the end of the initial week, at the first and third week with the three experimental diets,and after three days following the return of the egg diet, an 8 h primed continuous intravenous infusion with l-13 C-leucine was conducted (3 h, fast, 5 h fed - while subjects received hourly meals supplying the equivalent of 5/12 total daily intake). Estimation of leucine balance were carried out with measurements plasma free amino acids changes. Daily nitrogen balances were obtained through the study. Interpretation of plasma amino acids profile, and changes of leucine kinetics balances, indicated that the FAO diet was not able to maintain amino acids homeostasis whereas the MIT and the egg diets sustained body amino acids equilibrium with a positive amino acid balance. nitrogen balances tended to be more negative with the FAO diet but failed to show statistically significant differences among the three diets. The finding point out that it would be prudent to use the new, tentative recommended amino acid pattern (MIT diet 0 as the minimum physiological amino acid needs of healthy human adults (author)

  1. An AES and LEED study of carbon and oxygen sorption on copper surfaces

    OpenAIRE

    Oda, O.; Hanekamp, L.J.; Bootsma, G.A.

    1981-01-01

    The sorption of carbon and oxygen on cooper surfaces has been studied by AES and LEED. The carbon coverage has been estimated by measuring the substrate Auger peak attenuation upon changing the carbon coverage and by studying the coadsorption of oxygen and carbon on the surface. The effect of carbon on the background of derivative spectra is also reported.

  2. The effect of an eyes-closed dance-specific training program on dynamic balance in elite pre-professional ballet dancers: a randomized controlled pilot study.

    Science.gov (United States)

    Hutt, Kimberley; Redding, Emma

    2014-03-01

    Visual conditions for a dancer vary greatly between theatrical performance environments and dance studios, and this variability may be detrimental to their dynamic balance performance, particularly under stage lighting. In order to maintain balance control, dancers reportedly rely heavily on visual input, yet those who rely more on proprioceptive strategies for balancing have been found to be more stable. The purpose of this study was to assess the capability of an eyes-closed, dance-specific training program to nurture in dancers proprioceptive mechanisms that may facilitate their dynamic balance control. Eighteen elite pre-professional ballet dancers were randomly assigned to either a control (eyes open) or experimental (eyes closed) group for the intervention. The balance abilities of all subjects were tested using five dance-specific variations of the Star Excursion Balance Test before and after a 4 week balance intervention. Reach distance and time to complete the tests were recorded separately as indirect measurements of dynamic balance. The intervention consisted of dance-specific, eyes-closed exercises integrated into the dancers' daily ballet class and designed progressively to challenge the dancers' balance. During the intervention period, the control group undertook the same exercise program with their eyes open. Results revealed significant improvements in time to complete the three "timed" balance tests, and distances reached significantly improved in one of the two "reach" balance tests. No significant improvements were observed in the control group for any variation of the tests. These results indicate that dancers can be trained to adopt proprioceptive strategies to maintain dynamic balance, which consequently improves their balance performance. Such findings could encourage use of eyes-closed training in daily dance classes due to its potential to improve dancers' balance control. PMID:24568798

  3. Balanced sampling

    NARCIS (Netherlands)

    Brus, D.J.

    2015-01-01

    In balanced sampling a linear relation between the soil property of interest and one or more covariates with known means is exploited in selecting the sampling locations. Recent developments make this sampling design attractive for statistical soil surveys. This paper introduces balanced sampling

  4. A model study of the energy and mass balance of Chhota Shigri glacier in the Western Himalaya, India

    Directory of Open Access Journals (Sweden)

    F. Pithan

    2011-01-01

    Full Text Available The impact of climate change on Himalaya mountain glaciers is increasingly subject of public and scientific debate. However, observational data are sparse and important knowledge gaps remain in the understanding of what drives changes in these glaciers' mass balances. The present study investigates the glacier regime on Chhota Shigri, a benchmark glacier for the observation of climate change in the monsoon-arid transition zone of Western Himalaya. Results of an energy-balance model driven by reanalysis data and the observed mass balances from three years on 50 m altitude intervals across the glacier display a correlation coefficient of 0.974. Contrary to prior assumptions, monsoon precipitation accounts for a quarter to a third of total accumulation. It has an additional importance because it lowers the surface albedo during the ablation season. Results confirm radiation as the main energy source for melt on Himalaya glaciers. Latent heat flux acts as an important energy sink in the pre-monsoon season. Mass balance is most sensitive to changes in atmospheric humidity, changing by 900 mm w.e. per 10% change in humidity. Temperature sensitivity is 220 mm w.e.K−1. Model results using 21st century anomalies from a regional climate model based on the SRES A2 scenario suggest that a monsoon increase might offset the effect of warming.

  5. Understanding the context of balanced scorecard implementation: a hospital-based case study in pakistan

    Directory of Open Access Journals (Sweden)

    Ajmal Agha

    2011-03-01

    Full Text Available Abstract Background As a response to a changing operating environment, healthcare administrators are implementing modern management tools in their organizations. The balanced scorecard (BSC is considered a viable tool in high-income countries to improve hospital performance. The BSC has not been applied to hospital settings in low-income countries nor has the context for implementation been examined. This study explored contextual perspectives in relation to BSC implementation in a Pakistani hospital. Methods Four clinical units of this hospital were involved in the BSC implementation based on their willingness to participate. Implementation included sensitization of units towards the BSC, developing specialty specific BSCs and reporting of performance based on the BSC during administrative meetings. Pettigrew and Whipp's context (why, process (how and content (what framework of strategic change was used to guide data collection and analysis. Data collection methods included quantitative tools (a validated culture assessment questionnaire and qualitative approaches including key informant interviews and participant observation. Results Method triangulation provided common and contrasting results between the four units. A participatory culture, supportive leadership, financial and non-financial incentives, the presentation of clear direction by integrating support for the BSC in policies, resources, and routine activities emerged as desirable attributes for BSC implementation. The two units that lagged behind were more involved in direct inpatient care and carried a considerable clinical workload. Role clarification and consensus about the purpose and benefits of the BSC were noted as key strategies for overcoming implementation challenges in two clinical units that were relatively ahead in BSC implementation. It was noted that, rather than seeking to replace existing information systems, initiatives such as the BSC could be readily adopted if

  6. A Molecular Dynamics Study on the Confinement of Carbon Dioxide Molecules in Carbon Nanotubes

    Science.gov (United States)

    Lazor, Meagan; Rende, Deniz; Baysal, Nihat; Ozisik, Rahmi

    2012-02-01

    The influence of atmospheric carbon dioxide (CO2) concentration on global warming is considered as one of the primary environmental issues of the past two decades. The main source of CO2 emission is human activity, such as the use of fossil fuels in transportation and industrial plants. Following the release of Kyoto Protocol in 1997, effective ways of controlling CO2 emissions received much attention. As a result, various materials such as activated carbon, zeolites, and carbon nanotubes (CNTs) were investigated for their CO2 adsorbing properties. CNTs were reported to have CO2 adsorption capability twice that of activated carbon, hence they received the most attention. In the current study, single walled carbon nanotubes (SWNTs) were used as one dimensional nanoporous materials and their CO2 adsorption capacity was analyzed with Molecular Dynamics simulations. Results indicated that SWNTs are excellent CO2 adsorbers and their effectiveness increase at low CO2 concentrations. In addition, we showed that by varying temperature, CO2 can be removed from the SWNTs, providing a simple method to reuse SWNTs.

  7. Studies to Enhance Superconductivity in Thin Film Carbon

    Science.gov (United States)

    Pierce, Benjamin; Brunke, Lyle; Burke, Jack; Vier, David; Steckl, Andrew; Haugan, Timothy

    2012-02-01

    With research in the area of superconductivity growing, it is no surprise that new efforts are being made to induce superconductivity or increase transition temperatures (Tc) in carbon given its many allotropic forms. Promising results have been published for boron doping in diamond films, and phosphorus doping in highly oriented pyrolytic graphite (HOPG) films show hints of superconductivity.. Following these examples in the literature, we have begun studies to explore superconductivity in thin film carbon samples doped with different elements. Carbon thin films are prepared by pulsed laser deposition (PLD) on amorphous SiO2/Si and single-crystal substrates. Doping is achieved by depositing from (C1-xMx) single-targets with M = B4C and BN, and also by ion implantation into pure-carbon films. Previous research had indicated that Boron in HOPG did not elicit superconducting properties, but we aim to explore that also in thin film carbon and see if there needs to be a higher doping in the sample if trends were able to be seen in diamond films. Higher onset temperatures, Tc , and current densities, Jc, are hoped to be achieved with doping of the thin film carbon with different elements.

  8. Kinetic study of uranium carburization by different carbonated gases

    International Nuclear Information System (INIS)

    The kinetic study of the reaction U + CO2 and U + CO has been performed by a thermogravimetric method on a spherical uranium powder, in temperature ranges respectively from 460 to 690 deg. C and from 570 to 850 deg. C. The reaction with carbon dioxide leads to uranium dioxide. A carbon deposition takes place at the same time. The global reactions is the result of two reactions: U + 2 CO2 → UO2 + 2 CO U + CO2 → UO2 + C The reaction with carbon monoxide leads to a mixture of dioxide UO2, dicarbide UC2 and free carbon. The main reaction can be written. U + CO → 1/2 UO2 + 1/2 UC2 The free carbon results of the disproportionation of the carbon monoxide. A remarkable separation of the two phases UO2 and UC2 can be observed. A mechanism accounting for the phenomenon has been proposed. The two reactions U + CO2 and U + CO begin with a long germination period, after which, the reaction velocity seems to be limited in both cases by the ionic diffusion of oxygen through the uranium dioxide. (author)

  9. Home environmental influences on adolescents' energy balance related behaviours. The HEIA cohort study

    OpenAIRE

    2014-01-01

    The global obesity epidemic represents an enormous potential threat to public health, because overweight and obesity are major risk factors of non-communicable diseases. The prevalence of overweight has furthermore increased among children and adolescents worldwide, and creates a growing health challenge for the next generation as children who are overweight are more likely to become overweight and obese as adults. Dietary, physical activity and sedentary behaviours are energy balance related...

  10. Contributions of GPS occultations to Antarctica ice sheet mass balance studies

    OpenAIRE

    S. J. Ge; Shum, C.K.; Jens Wickert

    2002-01-01

    Antarctica is the coldest, stormiest and the most remote continent on Earth. Nearly 75% of the world's fresh water is trapped in the Antarctic ice sheets, which could significantly raise the global sea level if the ice sheets would melt. The continental ice sheet mass balance budget remains one of the largest uncertainties in the understanding of the causes of global sea level rise. Advanced gravity mapping satellite missions, such as CHAMP, GRACE and GOCE, are anticipated to provide signi...

  11. Balance study of twenty trace elements during total parenteral nutrition in man.

    Science.gov (United States)

    Jacobson, S; Wester P-O

    1977-01-01

    1. Balances of twenty trace elements (silver, arsenic, gold, bromine, cadmium, cobalt, chromium, caesium, copper, iron, mercury, lanthanum, molybdenum, rubidium, antimony, scandium, selenium, samarium, tungsten and zinc) have been determined in four male patients during total parenteral nutrition incliding fat emulsion and a special solution for addition of Fe, Zn, manganese, Cu, fluorine and iodine, besides calcium and magnesium, to the infusion solutions. 2. The analyses for trace elements were made with the aid of an ion-exchange technique based on neutron activation, and combined with subsequent gamma spectrometry. 3. The intended intravenous supply of trace elements correspond approximately to the analysed supply. However, all the other trace elements determined were found to be unintentionally administered in small amounts. 4. There was a substantial retention of Fe. Other elements retained were Ag, Co, Cr, Cu, Sb, Sc, and W. 5. Particularly Br and Rb were lost by the patients, but negative balances were also found for As, Au, Cd, Cs, Mo, Se and Zn. However, Zn was retained by one patient with short bowel syndrome. 6. The serum concentrations of thirteen (Ag, Br, Co, Cs, Cu, Fe, Hg, Mo, Rb, Sc, Se, W and Zn) of the trace elements were found to have some decrease during the period of total parenteral nutrition, mostly in accordance with the corresponding balance values, Fe, in particular, was found to have the derectional change in concentration. 7. The administration of trace elements is recommended in long-term total parenteral nutrition. PMID:402929

  12. Implementation Study of Dynamic Load Balancing Algorithm of Parallel Tree Computation on Clusters of Heterogeneous Workstation

    Institute of Scientific and Technical Information of China (English)

    Mohammed A.M. Ibrahim; Lu Xinda; M. SaifMokbel

    2005-01-01

    The rapid growth of interconnected high performance workstations has produced a new computing paradigm called clustered of workstations computing. In these systems load balance problem is a serious impediment to achieve good performance. The main concern of this paper is the implementation of dynamic load balancing algorithm,asynchronous Round Robin (ARR), for balancing workload of parallel tree computation depth-first-search algorithm on Cluster of Heterogeneous Workstations (COW) Many algorithms in artificial intelligence and other areas of computer science are based on depth first search in implicitty defined trees. For these algorithms a loadbalancing scheme is required, which is able to evenly distribute parts of an irregularly shaped tree over the workstations with minimal interprocessor communication and without prior knowledge of the tree's shape. For the( ARR ) algorithm only minimal interpreeessor communication is needed when necessary and it runs under the MPI (Message passing interface) that allows parallel execution on heterogeneous SUN cluster of workstation platform. The program code is written in C language and executed under UNIX operating system (Solaris version).

  13. Reproducibility of standing posture for X-ray radiography: a feasibility study of the BalancAid with healthy young subjects

    NARCIS (Netherlands)

    Dewi, Dyah Ekashanti Octorina; Veldhuizen, Albert G.; Burgerhof, Johannes G.M.; Purnama, I Ketut Eddy; Ooijen, van Peter M.A.; Wilkinson, Michael H.F.; Mengko, Tati Latifah Erawati Rajab; Verkerke, Gijsbertus J.

    2010-01-01

    Unreliable spinal X-ray radiography measurement due to standing postural variability can be minimized by using positional supports. In this study, we introduce a balancing device, named BalancAid, to position the patients in a reproducible position during spinal X-ray radiography. This study aimed t

  14. Reproducibility of Standing Posture for X-Ray Radiography : A Feasibility Study of the BalancAid with Healthy Young Subjects

    NARCIS (Netherlands)

    Dewi, Dyah Ekashanti Octorina; Veldhuizen, Albert G.; Burgerhof, Johannes G.M.; Purnama, I Ketut Eddy; Ooijen, Peter M.A. van; Wilkinson, Michael H.F.; Mengko, Tati Latifah Erawati Rajab; Verkerke, Gijsbertus Jacob

    2010-01-01

    Unreliable spinal X-ray radiography measurement due to standing postural variability can be minimized by using positional supports. In this study, we introduce a balancing device, named BalancAid, to position the patients in a reproducible position during spinal X-ray radiography. This study aimed t

  15. Convergence of the effect of root hydraulic functioning and root hydraulic redistribution on ecosystem water and carbon balance across divergent forest ecosystems

    Science.gov (United States)

    domec, J.; King, J. S.; Ogée, J.; Noormets, A.; Warren, J.; Meinzer, F. C.; Sun, G.; Jordan-Meille, L.; Martineau, E.; Brooks, R. J.; Laclau, J.; Battie Laclau, P.; McNulty, S.

    2012-12-01

    trees to droughts. Under future conditions, T is predicted to stay the same at the Duke mixed hardwood forest, but to decline slightly at the coastal loblolly pine plantation and slightly increase at the old-growth ponderosa pine stand and the eucalyptus plantation. As a consequence, water use efficiency in all sites was predicted to improve dramatically under future climate conditions. Our simulations also showed that the negative effect of drier nights on HR would be greater under future climate conditions. Assuming no increase in stomatal control with increasing drier nights, increased vapor pressure deficit at night under future conditions was sufficient to drive significant nighttime T at all sites , which reduced HR, because the plant and the atmosphere became a sink for hydraulically redistributed water . We concluded that the predicted reductions in HR under future climate conditions are expected to play an important regulatory role in land-atmosphere interactions by affecting whole ecosystem carbon and water balance. We suggest that root distribution should be treated dynamically in response to climate change and that HR and its interactions with rooting depth and soil texture should be implemented in soil-vegetation-atmosphere transfer models.

  16. Study of Carbon Emission in Computing Scenario

    Directory of Open Access Journals (Sweden)

    Mr. Nikhil B. Dhake Mr. Pankaj M. Poul Prof. Pranav R. Shriram Prof. Kanchan V. Wankhade

    2011-12-01

    Full Text Available This paper presents a case study of what is green computing, why we need to go green computing & will tell you how to minimize the energy consumption as well how to lessen the CO2 emission by going Green Computing. The huge amount of computing manufactured worldwide has a direct impact on environment issues and scientists are conducting numerous studies in order to reduce the negative impact of computing technology on environment. Energy consumption in the datacenter reached the highs. A large corporate IT infrastructure, consumes as much as the energy produced by five power plants over the same time period. This case study will provide a rich source for anyone interested in green computing research.

  17. Kinetic study of uranium residue dissolution in ammonium carbonate media

    International Nuclear Information System (INIS)

    The purpose of this study was to determine the kinetics of the dissolution of a uranium residue in ammonium carbonate media. The residue is generated in the production of medical isotopes. The effects of parameters, such as varying peroxide and carbonate concentrations, dissolution time as well as temperature on the extraction rate have been separately studied. Results indicate complete dissolution of the residue at 60 deg C, after 30 min, in ammonium carbonate solution enriched with hydrogen peroxide. The yield and rate of uranium extraction were found to increase as a function of both temperature, in the range of 25-60 deg C, and hydrogen peroxide concentration. The extraction process was governed by chemical reaction as the activation energy was found to be 45.5 kJ/mol. The order of reaction with respect to uranium concentration was found to be approximately first order. (author)

  18. Associations between active video gaming and other energy-balance related behaviours in adolescents: a 24-hour recall diary study

    OpenAIRE

    Simons, Monique; Mai J M Chinapaw; Brug, Johannes; Seidell, Jaap; Vet, Emely

    2015-01-01

    Background Active video games may contribute to reducing time spent in sedentary activities, increasing physical activity and preventing excessive weight gain in adolescents. Active video gaming can, however, only be beneficial for weight management when it replaces sedentary activities and not other physical activity, and when it is not associated with a higher energy intake. The current study therefore examines the association between active video gaming and other energy-balance-related beh...

  19. Mitigative effects of spermidine on photosynthesis and carbon-nitrogen balance of cucumber seedlings under Ca(NO3)2 stress.

    Science.gov (United States)

    Du, Jing; Shu, Sheng; Shao, Qiaosai; An, Yahong; Zhou, Heng; Guo, Shirong; Sun, Jin

    2016-01-01

    Ca(NO3)2 stress is one of the most serious constraints to plants production and limits the plants growth and development. Application of polyamines is a convenient and effective approach for enhancing plant salinity tolerance. The present investigation aimed to discover the photosynthetic carbon-nitrogen (C-N) mechanism underlying Ca(NO3)2 stress tolerance by spermidine (Spd) of cucumber (Cucumis sativus L. cv. Jinyou No. 4). Seedling growth and photosynthetic capacity [including net photosynthetic rate (P N), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr)] were significantly inhibited by Ca(NO3)2 stress (80 mM). However, a leaf-applied Spd (1 mM) treatment alleviated the reduction in growth and photosynthesis in cucumber caused by Ca(NO3)2 stress. Furthermore, the application of exogenous Spd significantly decreased the accumulation of NO3 (-) and NH4 (+) caused by Ca(NO3)2 stress and remarkably increased the activities of N metabolism enzymes simultaneously. In addition, photosynthesis N-use efficiency (PNUE) and free amino acids were significantly enhanced by exogenous Spd in response to Ca(NO3)2 stress, thus promoting the biosynthesis of N containing compounds and soluble protein. Also, the amounts of several carbohydrates (including sucrose, fructose and glucose), total C content and the C/N radio increased significantly in the presence of Spd. Based on our results, we suggest that exogenous Spd could effectively accelerate nitrate transformation into amino acids and improve cucumber plant photosynthesis and C assimilation, thereby enhancing the ability of the plants to maintain their C/N balance, and eventually promote the growth of cucumber plants under Ca(NO3)2 stress.

  20. THE ORTHOPAEDIC REHABILITATION OF BALANCE: AN EXPERIMENTAL STUDY ON THE ROLE OF MENTAL IMAGERY AND EMOTIONAL VARIABLES.

    Directory of Open Access Journals (Sweden)

    Santo F. Di Nuovo

    2015-05-01

    Full Text Available Mental Imagery (i.e., processing of objects’ properties and spatial relations, including the ability of mentally rotating and manipulating objects in the space, is relevant for movement and its development, and particularly for rehabilitation of motor skills. Few studies aimed at assessing  the efficacy of imagery training used objective scores of Mental Imagery skills, preferring self-evaluations of these abilities reported by the subjects themselves. The aim of the paper was to explore the relevance of Mental Imagery, assessed by objective tests, in predicting the improvement of balance skills, after a standard rehabilitative training in orthopaedic settings; taking into account also emotional variables as anxiety and depression. A controlled study was conducted assessing the changes in balance skills after rehabilitative training. The sample was composed of 30 orthopaedic inpatients (females 66.7%, age range 47-91 years. To measure the dependent variable for pre-post assessment, B-scale from Performance-oriented mobility assessment test (POMA was used. Independent variables were measured using Mental Imagery Test, Mini-Mental State Examination, Hamilton Depression Rating Scale and Hamilton Anxiety Rating Scales. The best predictor of improvement in balance after rehabilitation is the Mental Imagery test, followed by age and mental efficiency. Anxiety predicts negatively the improvement, while education and depression appear to influence less the rehabilitation process. In conclusion, the study demonstrates that mental imagery is relevant in helping balance rehabilitation. A training of this function could be essential for clinical practice; the trainers should assess preliminarily the subject's attitude and ability to use mental imagery, with the aim of optimizing the rehabilitative process.

  1. Informational Balance

    OpenAIRE

    Müller, Henrik Høeg

    2011-01-01

    The title of my talk is “Informational balance. Understanding Romance and Germanic Compounding in a lexico-typological perspective”. What I basically mean by informational balance is that semantic content is distributed systematically differently between nouns and verbs in the Romance and Germanic languages, and that this distribution is complementary. I shall explain that in detail in a minute, but first I shall introduce you to the problem, which I believe can be explained on the basis of t...

  2. Runoff components and mean residence times in water balance studies using environmental isotopes

    International Nuclear Information System (INIS)

    the subsurface reservoirs were derived from comparisons of the 3H and 2H or 18O input and output functions, the specific hydrological models and the model age distributions applied. Tr varies between 1.5 and 4 years in the studied areas, the results from stable-isotope and 3H data being in good agreement (Maloszewski, P., Rauert, W. Stichler, W., Herrmann, A., J. Hydrol. 66 (1983)). By introducing hydrological data, such as mean and minimum stream flow, it was possible to discriminate between two separate sub-reservoirs with different Tr values, i.e. 0.1-1 year and 4-7 years. The combination of hydrological and isotopical investigation methods enables a new insight into the water balances of the studied catchment areas. For example, the infiltration rates amount to about 50% of the precipitation depths, allowing for an evaporation loss of 25%. The subsurface storage volumes are of the order of 108 times the discharge, with Tr of 2.5 years. Assuming effective porosities of 20%, the calculated mean aquifer thickness is of the order of 10-15 times the precipitation depths. (author)

  3. Integrated Experimental and Modeling Studies of Mineral Carbonation as a Mechanism for Permanent Carbon Sequestration in Mafic/Ultramafic Rocks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhengrong [Yale Univ., New Haven, CT (United States); Qiu, Lin [Yale Univ., New Haven, CT (United States); Zhang, Shuang [Yale Univ., New Haven, CT (United States); Bolton, Edward [Yale Univ., New Haven, CT (United States); Bercovici, David [Yale Univ., New Haven, CT (United States); Ague, Jay [Yale Univ., New Haven, CT (United States); Karato, Shun-Ichiro [Yale Univ., New Haven, CT (United States); Oristaglio, Michael [Yale Univ., New Haven, CT (United States); Zhu, Wen-Iu [Univ. of Maryland, College Park, MD (United States); Lisabeth, Harry [Univ. of Maryland, College Park, MD (United States); Johnson, Kevin [Univ. of Hawaii, Honolulu, HI (United States)

    2014-09-30

    A program of laboratory experiments, modeling and fieldwork was carried out at Yale University, University of Maryland, and University of Hawai‘i, under a DOE Award (DE-FE0004375) to study mineral carbonation as a practical method of geologic carbon sequestration. Mineral carbonation, also called carbon mineralization, is the conversion of (fluid) carbon dioxide into (solid) carbonate minerals in rocks, by way of naturally occurring chemical reactions. Mafic and ultramafic rocks, such as volcanic basalt, are natural candidates for carbonation, because the magnesium and iron silicate minerals in these rocks react with brines of dissolved carbon dioxide to form carbonate minerals. By trapping carbon dioxide (CO2) underground as a constituent of solid rock, carbonation of natural basalt formations would be a secure method of sequestering CO2 captured at power plants in efforts to mitigate climate change. Geochemical laboratory experiments at Yale, carried out in a batch reactor at 200°C and 150 bar (15 MPa), studied carbonation of the olivine mineral forsterite (Mg2SiO4) reacting with CO2 brines in the form of sodium bicarbonate (NaHCO3) solutions. The main carbonation product in these reactions is the carbonate mineral magnesite (MgCO3). A series of 32 runs varied the reaction time, the reactive surface area of olivine grains and powders, the concentration of the reacting fluid, and the starting ratio of fluid to olivine mass. These experiments were the first to study the rate of olivine carbonation under passive conditions approaching equilibrium. The results show that, in a simple batch reaction, olivine carbonation is fastest during the first 24 hours and then slows significantly and even reverses. A natural measure of the extent of carbonation is a quantity called the carbonation fraction, which compares the amount of carbon removed from solution, during a run, to the maximum amount

  4. STUDY ON THE OVERALL PRESSURE BALANCE OF A DOWNFLOW CIRCULATING FLUIDIZED BED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Hengzhi Chen; Dawei Yang; Hongzhong Li; Shiyu Tan

    2006-01-01

    A pressure balance model for a circulating fluidized bed unit that incorporates a downer has been proposed. The model predictions were validated with the experimental data obtained from a special cold-model circulating fluidized bed. Comparison of the operation stability between a CFB downer and a CFB riser has been carried out. Only one critical gas velocity exists in the CFB-riser for a given riser solids flux, while there can be many critical gas velocities for the operation of a CFB downer. Therefore, it is possible to achieve high solids concentration in a CFB downer if appropriate operating conditions are used.

  5. Molecular-dynamic studies of carbon-water-carbon composite nanotubes.

    Science.gov (United States)

    Zou, Jian; Ji, Baohua; Feng, Xi-Qiao; Gao, Huajian

    2006-11-01

    We recently reported the discovery via molecular-dynamic simulations that single-walled carbon nanotubes (SWCNTs) with different diameters, lengths, and chiralities can coaxially self-assemble into multi-walled carbon nanotubes (MWCNTs) in water via the spontaneous insertion of smaller tubes into larger ones. Here, we extend that study to investigate the various water structures formed between two selected SWCNTs after such coaxial assembly. Depending on the tube geometry, typical water structures, besides the bulk phase, include a one-dimensional (1D) ordered water chain inside the smaller tube, a uniform or nonuniform water shell between the two tubes, and a "boundary layer" of water near the exterior wall of the larger tube. It was found that a concentric water shell consisting of up to three layers of water molecules can form between the two SWCNTs, which leads to a class of carbon-water-carbon composite nanotubes. Analysis of the potential energy of the SWCNT-water system indicated that the composite nanotubes are stabilized by both the tube-tube and tube-water van der Waals interactions. Geometrically confined between the two SWCNTs, water mono- and bilayers are found to be stable, highly condensed, and ordered, although the average number of hydrogen bonds per water molecule is reduced. In contrast, a water trilayer between the two CNTs can be easily disrupted by thermal fluctuations.

  6. An integrated study of a Campeche Bay fractured carbonate reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Hampton, D.W.; Hernandez, J.G.; Vasques, G.A.V.; Aquino, E.V.; Barton, C.; Laude, L.; Lockhart, A.M.E.; Peebles, R.G.

    1994-12-31

    This paper provides a case study in the reservoir description of a fractured carbonate by a multi-disciplinary team. It illustrates how the synergistic interaction of team members during data analysis and model building resulted in: (1) the identification of previously unrecognized links between several reservoir characteristics; (2) produced a superior reservoir model; and (3) increased the likelihood of successful development. In summary, identification, characterization, and delineation of fractured intervals within the deepwater carbonate succession resulted in a preliminary 3-D model of both the static and dynamic properties for the Cretaceous reservoir of the Yum Field which, through reservoir simulation, will provide a predictive tool for development planning.

  7. A study of contract legal issues in Chinese carbon market

    Institute of Scientific and Technical Information of China (English)

    Pei Qing; Jiang Dongmei; Zhang Mengheng

    2009-01-01

    Clean Development Mechanism (CDM) has given birth to an international carbon trading market prosperity, which provides developing countries with valuable opportunities to address climate change issues together with economic development and environmental improvement to achieve the sustainable goal. China, as the biggest carbon market, has caught worldwide attention. However, most studies of CDM focus on economics and environmental science, few on its legal problems. Transaction activities are the essence of market mechanism. To protect the benefits of market participators and regulate the market orders, the Contract Law takes this important role along with development of market mechanism. Therefore, this paper only focuses on the carbon market in China, with the assessment of the risks in the CDM development first. The involved contracts will be identified and analyzed to point out the major contract legal issues in Chinese carbon market. In the meantime, this paper further discussses that measurements at both private level and governmental level should be taken to protect and realize the utility and equality of contract in the carbon market.

  8. Reaction studies of hot silicon, germanium and carbon atoms

    Energy Technology Data Exchange (ETDEWEB)

    Gaspar, P.P.

    1990-11-01

    The goal of this project was to increase the authors understanding of the interplay between the kinetic and electronic energy of free atoms and their chemical reactivity by answering the following questions: (1) what is the chemistry of high-energy carbon silicon and germanium atoms recoiling from nuclear transformations; (2) how do the reactions of recoiling carbon, silicon and germanium atoms take place - what are the operative reaction mechanisms; (3) how does the reactivity of free carbon, silicon and germanium atoms vary with energy and electronic state, and what are the differences in the chemistry of these three isoelectronic atoms This research program consisted of a coordinated set of experiments capable of achieving these goals by defining the structures, the kinetic and internal energy, and the charge states of the intermediates formed in the gas-phase reactions of recoiling silicon and germanium atoms with silane, germane, and unsaturated organic molecules, and of recoiling carbon atoms with aromatic molecules. The reactions of high energy silicon, germanium, and carbon atoms created by nuclear recoil were studied with substrates chosen so that their products illuminated the mechanism of the recoil reactions. Information about the energy and electronic state of the recoiling atoms at reaction was obtained from the variation in end product yields and the extent of decomposition and rearrangement of primary products (usually reactive intermediates) as a function of total pressure and the concentration of inert moderator molecules that remove kinetic energy from the recoiling atoms and can induce transitions between electronic spin states. 29 refs.

  9. Feasibility study of algae-based Carbon Dioxide capture

    Science.gov (United States)

    SUMMARY: The biomass of microalgae contains approximately 50% carbon, which is commonly obtained from the atmosphere, but can also be taken from commercial sources that produce CO2, such as coal-fired power plants. A study of operational demonstration projects is being undertak...

  10. Study on neutron radiation field of carbon ions therapy

    CERN Document Server

    Xu, Jun-Kui; Li, Wu-Yuan; Yan, Wei-Wei; Chen, Xi-Meng; Mao, Wang; Pang, Cheng-Guo

    2015-01-01

    Carbon ions offer significant advantages for deep-seated local tumors therapy due to their physical and biological properties. Secondary particles, especially neutrons caused by heavy ion reactions should be carefully considered in treatment process and radiation protection. For radiation protection purposes, the FLUKA Code was used in order to evaluate the radiation field at deep tumor therapy room of HIRFL in this paper. The neutron energy spectra, neutron dose and energy deposition of carbon ion and neutron in tissue-like media was studied for bombardment of solid water target by 430MeV/u C ions. It is found that the calculated neutron dose have a good agreement with the experimental date, and the secondary neutron dose may not exceed one in a thousand of the carbon ions dose at Bragg peak area in tissue-like media.

  11. Efficacy of focal mechanic vibration treatment on balance in Charcot-Marie-Tooth 1A disease: a pilot study.

    Science.gov (United States)

    Pazzaglia, Costanza; Camerota, F; Germanotta, M; Di Sipio, E; Celletti, C; Padua, L

    2016-07-01

    Patients affected by Charcot-Marie-Tooth (CMT) disease experience an impaired balance. Although the causes of the postural instability are not fully understood, somatosensory system seems to play a key role. Mechanical vibration seems to act on the somatosensory system and to improve its function. The aim of our study was to evaluate the effects of focal mechanical vibration (fMV) on the balance of CMT 1A patients. We enrolled 14 genetically confirmed CMT 1A patients (8 female and 6 male, mean age 492 years, range 32-74, mean duration of disease: 13 years, range 1-30). Patients underwent a 3-day fMV treatment on quadriceps and triceps surae and were evaluated before the treatment as well as 1 week and 1 month after the end of the treatment. The primary outcome measure was the Berg Balance Scale (BBS) and the secondary were the Dynamic Gait Index (DGI), the 6 Min Walking Test (6MWT), the muscular strength of lower limbs, the Quality of Life (QoL) questionnaire and the stabilometric variables. The statistical analysis showed a significant modification of the BBS due to the effect of treatment (p CMT 1A patients determined an improvement of balance as detected by the BBS. The concurrent improvement of stabilometric variables in the eyes closed condition only suggests that fMV acts mostly on somatosensory afferences. Further studies are needed to confirm these data on a larger sample of CMT patients. PMID:27177999

  12. A case-study on the accuracy of mass balances for xenobiotics in full-scale wastewater treatment plants.

    Science.gov (United States)

    Majewsky, Marius; Farlin, Julien; Bayerle, Michael; Gallé, Tom

    2013-04-01

    Removal efficiencies of micropollutants in wastewater treatment plants (WWTPs) are usually evaluated from mass balance calculations using a small number of observations drawn from short sampling campaigns. Since micropollutant loads can vary greatly in both influent and effluent and reactor tanks exhibit specific hydraulic residence times, these short-term approaches are particularly prone to yield erroneous removal values. A detailed investigation of micropollutant transit times at full-scale and on how this affects mass balancing results was still lacking. The present study used hydraulic residence time distributions to scrutinize the match of influent loads to effluent loads of 10 polar micropollutants with different influent dynamics in a full-scale WWTP. Prior hydraulic modeling indicated that a load sampled over one day in the effluent is composed of influent load fractions of five preceding days. Results showed that the error of the mass balance can be reduced with increasing influent sampling duration. The approach presented leads to a more reliable estimation of the removal efficiencies of those micropollutants which can be constantly detected in influents, such as pharmaceuticals, but provides no advantage for pesticides due to their sporadic occurrence. The mismatch between sampled influent and effluent loads was identified as a major error source and an explanation was provided for the occurrence of negative mass balances regularly reported. This study indicates that the accurate determination of global removal values is only feasible in full-scale investigations with sampling durations much longer than 1 day. In any case, the uncertainty of these values needs to be reported when used in removal assessment, model selection or validation. PMID:23474799

  13. Efficacy of focal mechanic vibration treatment on balance in Charcot-Marie-Tooth 1A disease: a pilot study.

    Science.gov (United States)

    Pazzaglia, Costanza; Camerota, F; Germanotta, M; Di Sipio, E; Celletti, C; Padua, L

    2016-07-01

    Patients affected by Charcot-Marie-Tooth (CMT) disease experience an impaired balance. Although the causes of the postural instability are not fully understood, somatosensory system seems to play a key role. Mechanical vibration seems to act on the somatosensory system and to improve its function. The aim of our study was to evaluate the effects of focal mechanical vibration (fMV) on the balance of CMT 1A patients. We enrolled 14 genetically confirmed CMT 1A patients (8 female and 6 male, mean age 492 years, range 32-74, mean duration of disease: 13 years, range 1-30). Patients underwent a 3-day fMV treatment on quadriceps and triceps surae and were evaluated before the treatment as well as 1 week and 1 month after the end of the treatment. The primary outcome measure was the Berg Balance Scale (BBS) and the secondary were the Dynamic Gait Index (DGI), the 6 Min Walking Test (6MWT), the muscular strength of lower limbs, the Quality of Life (QoL) questionnaire and the stabilometric variables. The statistical analysis showed a significant modification of the BBS due to the effect of treatment (p < 0.05). A significant modification was also found in the DGI (p < 0.05). Concerning the stabilometric variables we found significant changes only for the eyes closed condition; in particular, a significant decrease was found in VelocityML (p < 0.05) and Sway path length (p < 0.05). The fMV treatment applied on lower limbs of CMT 1A patients determined an improvement of balance as detected by the BBS. The concurrent improvement of stabilometric variables in the eyes closed condition only suggests that fMV acts mostly on somatosensory afferences. Further studies are needed to confirm these data on a larger sample of CMT patients.

  14. Carbon-13 NMR studies of liquid crystals