WorldWideScience

Sample records for anthropogenic enhancements due

  1. Uncertainty of Climate Response to Natural and Anthropogenic Forcings Due to Different Land Use Scenarios

    Institute of Scientific and Technical Information of China (English)

    Alexey V. ELISEEV; Igor I. MOKHOV

    2011-01-01

    The A.M.Obukhov Institute of Atmospheric Physics,Russian Academy of Sciences (IAP RAS) climate model (CM) of intermediatc complexity is extended by a spatially explicit terrestrial carbon cycle module.Numerical experiments with the IAP RAS CM are performed forced by the reconstructions of anthropogenic and natural forcings for the 16th to the 20th centuries and by combined SRES (Special Report on Emission Scenarios) A2-LUH (Land Use Harmonization) anthropogenic scenarios for the 21st century.Hereby,the impact of uncertainty in land-use scenarios on results of simulations with a coupled climate-carbon cycle model is tested.The simulations of the model realistically reproduced historical changes in carbon cycle characteristics.In the IAP RAS CM,climate warming reproduced in the 20th and 21st centuries enhanced terrestrial net primary production but terrestrial carbon uptake was suppressed due to an overcompensating increase in soil respiration.Around year 2100,the simulations the model forced by different land use scenarios diverged markedly,by about 70 Pg (C) in terms of biomass and soil carbon stock but they differed only by about 10 in terms of atmospheric carbon dioxide content.

  2. Response of air stagnation frequency to anthropogenically enhanced radiative forcing

    International Nuclear Information System (INIS)

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) air stagnation index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21st century climate change (SRESA1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase by 12–25% relative to late-20th century stagnation frequencies (3–18 + days yr−1). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21st century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming. (letter)

  3. Response of air stagnation frequency to anthropogenically enhanced radiative forcing.

    Science.gov (United States)

    Horton, Daniel E; Harshvardhan; Diffenbaugh, Noah S

    2012-01-01

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) Air Stagnation Index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21(st) century climate change (SRES A1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase 12-to-25% relative to late-20(th) century stagnation frequencies (3-18+ days/year). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21(st) century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming. PMID:23284587

  4. Global premature mortality due to anthropogenic outdoor air pollution and the contribution of past climate change

    International Nuclear Information System (INIS)

    Increased concentrations of ozone and fine particulate matter (PM2.5) since preindustrial times reflect increased emissions, but also contributions of past climate change. Here we use modeled concentrations from an ensemble of chemistry–climate models to estimate the global burden of anthropogenic outdoor air pollution on present-day premature human mortality, and the component of that burden attributable to past climate change. Using simulated concentrations for 2000 and 1850 and concentration–response functions (CRFs), we estimate that, at present, 470 000 (95% confidence interval, 140 000 to 900 000) premature respiratory deaths are associated globally and annually with anthropogenic ozone, and 2.1 (1.3 to 3.0) million deaths with anthropogenic PM2.5-related cardiopulmonary diseases (93%) and lung cancer (7%). These estimates are smaller than ones from previous studies because we use modeled 1850 air pollution rather than a counterfactual low concentration, and because of different emissions. Uncertainty in CRFs contributes more to overall uncertainty than the spread of model results. Mortality attributed to the effects of past climate change on air quality is considerably smaller than the global burden: 1500 (−20 000 to 27 000) deaths yr−1 due to ozone and 2200 (−350 000 to 140 000) due to PM2.5. The small multi-model means are coincidental, as there are larger ranges of results for individual models, reflected in the large uncertainties, with some models suggesting that past climate change has reduced air pollution mortality. (letter)

  5. Biochemical changes in plant leaves as a biomarker of pollution due to anthropogenic activity.

    Science.gov (United States)

    Thawale, P R; Satheesh Babu, S; Wakode, R R; Singh, Sanjeev Kumar; Kumar, Sunil; Juwarkar, A A

    2011-06-01

    The air pollution due to anthropogenic activities seriously affected human life, vegetation, and heritage as well. The vegetation cover in and around the city mitigates the air pollution by acting as a sink for pollution. An attempt was made to evaluate biochemical changes occurred in four selected plant species, namely Azadirachta indica, Mangifera indica, Delonix regia, and Cassia fistula of residential, commercial, and industrial areas of Nagpur city in India. It was observed that the correlated values of air pollutants and plant leaves characteristics alter foliar biochemical features (i.e., chlorophyll and ascorbic acid content, pH and relative water content) of plants due to air pollution. The changes in air pollution tolerance index of plants was also estimated which revealed that these plants can be used as a biomarker of air pollution. PMID:20721619

  6. Imbalance of Nature due to Anthropogenic Activities in the Bay of Bacorehuis, Sinaloa, Mexico

    Science.gov (United States)

    Torrecillas Nunez, C.; Cárdenas Cota, H.

    2013-05-01

    Pollution is further enhancing water scarcity by reducing water usability downstream, globally the most prevalent water quality problem is eutrophication, a result of high-nutrient loads, which substantially impairs beneficial uses of water. Projected food production needs and increasing wastewater effluents associated with an increasing population over the next three decades suggest a 10%-15% increase in the river input of nitrogen loads into coastal ecosystems (UNO, 2009). Our study in the Bay of Bacorehuis in the State of Sinaloa, which was carried out due to a request from local fishermen who wanted to find out the reason for fishing stocks depletion, confirmed this trend with the consequent imbalance of nature. Sinaloa depends heavily on intensive agricultural production to support its economy which in turn relies on water irrigation and the application of agro-chemicals. The research project included a desk top study of geophysical and environmental factors as well as sampling and testing of the water. In addition we carried out socio-economic research to find out the impact on the local community of the imbalance caused by anthropogenic activities in the watershed upstream from the Bay. Our research established that the Bay of Bacorehuis is contaminated by organic matter, bacteria coliforms, pesticides and mercury due to the discharge of surplus runoff generated by irrigation of farmlands into drainage networks as well as the discharge of untreated industrial and domestic wastewater form more than 24,000 inhabitants. The main contaminants detected in the water bodies were organic matter, faecal coliforms, mercury, dimethoate, endosulfan, heptachlor, DDE, DDT, organonitrogen, synthetic pyrethroid, chlorothalonil, ethion, endosulfan, diazinon, malathion and chlorpyrifos. Contaminants in sediments included the pesticides endosulfan, heptachlor, DDE, DDT, organophosphates, organonitrogen and synthetic pyrethroids. Natural water courses have been highly modified

  7. Anthropogenic selection enhances cancer evolution in Tasmanian devil tumours

    OpenAIRE

    Ujvari, Beata; Pearse, Anne-Maree; Swift, Kate; Hodson, Pamela; Hua, Bobby; Pyecroft, Stephen; Taylor, Robyn; Hamede, Rodrigo; Jones, Menna; Belov, Katherine; Madsen, Thomas

    2013-01-01

    The Tasmanian Devil Facial Tumour Disease (DFTD) provides a unique opportunity to elucidate the long-term effects of natural and anthropogenic selection on cancer evolution. Since first observed in 1996, this transmissible cancer has caused local population declines by >90%. So far, four chromosomal DFTD variants (strains) have been described and karyotypic analyses of 253 tumours showed higher levels of tetraploidy in the oldest strain. We propose that increased ploidy in the oldest strain m...

  8. Polychaete richness and abundance enhanced in anthropogenically modified estuaries despite high concentrations of toxic contaminants.

    Directory of Open Access Journals (Sweden)

    Katherine A Dafforn

    Full Text Available Ecological communities are increasingly exposed to multiple chemical and physical stressors, but distinguishing anthropogenic impacts from other environmental drivers remains challenging. Rarely are multiple stressors investigated in replicated studies over large spatial scales (>1000 kms or supported with manipulations that are necessary to interpret ecological patterns. We measured the composition of sediment infaunal communities in relation to anthropogenic and natural stressors at multiple sites within seven estuaries. We observed increases in the richness and abundance of polychaete worms in heavily modified estuaries with severe metal contamination, but no changes in the diversity or abundance of other taxa. Estuaries in which toxic contaminants were elevated also showed evidence of organic enrichment. We hypothesised that the observed response of polychaetes was not a 'positive' response to toxic contamination or a reduction in biotic competition, but due to high levels of nutrients in heavily modified estuaries driving productivity in the water column and enriching the sediment over large spatial scales. We deployed defaunated field-collected sediments from the surveyed estuaries in a small scale experiment, but observed no effects of sediment characteristics (toxic or enriching. Furthermore, invertebrate recruitment instead reflected the low diversity and abundance observed during field surveys of this relatively 'pristine' estuary. This suggests that differences observed in the survey are not a direct consequence of sediment characteristics (even severe metal contamination but are related to parameters that covary with estuary modification such as enhanced productivity from nutrient inputs and the diversity of the local species pool. This has implications for the interpretation of diversity measures in large-scale monitoring studies in which the observed patterns may be strongly influenced by many factors that covary with anthropogenic

  9. Anthropogenic selection enhances cancer evolution in Tasmanian devil tumours.

    Science.gov (United States)

    Ujvari, Beata; Pearse, Anne-Maree; Swift, Kate; Hodson, Pamela; Hua, Bobby; Pyecroft, Stephen; Taylor, Robyn; Hamede, Rodrigo; Jones, Menna; Belov, Katherine; Madsen, Thomas

    2014-02-01

    The Tasmanian Devil Facial Tumour Disease (DFTD) provides a unique opportunity to elucidate the long-term effects of natural and anthropogenic selection on cancer evolution. Since first observed in 1996, this transmissible cancer has caused local population declines by >90%. So far, four chromosomal DFTD variants (strains) have been described and karyotypic analyses of 253 tumours showed higher levels of tetraploidy in the oldest strain. We propose that increased ploidy in the oldest strain may have evolved in response to effects of genomic decay observed in asexually reproducing organisms. In this study, we focus on the evolutionary response of DFTD to a disease suppression trial. Tumours collected from devils subjected to the removal programme showed accelerated temporal evolution of tetraploidy compared with tumours from other populations where no increase in tetraploid tumours were observed. As ploidy significantly reduces tumour growth rate, we suggest that the disease suppression trial resulted in selection favouring slower growing tumours mediated by an increased level of tetraploidy. Our study reveals that DFTD has the capacity to rapidly respond to novel selective regimes and that disease eradication may result in novel tumour adaptations, which may further imperil the long-term survival of the world's largest carnivorous marsupial. PMID:24567746

  10. Predictions of Flow Duration Curve Shifts Due to Anthropogenic and Climatic Changes

    Science.gov (United States)

    Henry, N. F.; Kroll, C. N.; Endreny, T. A.

    2014-12-01

    Methods are needed to understand and predict streamflows in systems undergoing anthropogenic and climatic alteration. This study is motivated by a need to develop methods to accurately estimate historical and future flow regimes of the Delaware River to inform management decisions for the endangered dwarf wedgemussel (Alasmidonta heterodon). Many streamflow regimes in this system have undergone substantial alteration within the past 100 years. Here, flow duration curves (FDCs), a common hydrologic tool used to assess flow regimes, are created and examined at 145 Delaware River Basin catchments. These catchments have experienced various hydrologic alterations, including land use changes, water withdrawals, and river regulation due to dams and reservoirs. Linear regression models are developed for various percentile flows across a FDC. These models use watershed characteristics that describe observed flow regimes in altered as well as unaltered systems. The characteristics that have the most significant influence on the shape of the FDCs are then identified and isolated as descriptors of the alteration. Once these models are developed to include these key variables, given a specific alteration (e.g. fresh water withdrawals, change in annual precipitation, etc.), a new flow regime can be estimated. Preliminary results indicate that certain watershed characteristics related to alteration (e.g. magnitude of land fragmentation, water withdrawals, hydrologic disturbance index) are significant in our models and influence FDC patterns. The results of this study may prove to have broader applications in regards to water resources management as the methods developed here may serve as a predictive tool as human interference and climatic changes continue to alter flow regimes.

  11. Sediment budget variation at watershed scale due to anthropogenic pressures, and its relationship to coastal erosion

    Science.gov (United States)

    Aiello, Antonello; Adamo, Maria; Canora, Filomena

    2014-05-01

    The transfer of sediments from hydrographic basins towards the coast is a significant pathway of material transfer on Earth. In sedimentary environment, the main portion of sediment that enters the coastal areas is derived originally from erosion in the coastal watersheds. Extensive anthropogenic pressures carried out within coastal basins have long shown negative impacts on littoral environments. In fluvial systems, sediments trapped behind dams and in-stream gravel mining cause the reduction in sediment supply to the coast. Along the Jonian littoral of the Basilicata Region (southern Italy), natural coastal processes have been severely disrupted since the second half of the 20th century as a result of riverbed sand and gravel mining and dam construction, when economic advantages were measured in terms of the development of infrastructure, water storage, and hydropower production for the agricultural, industrial and socio-economic development of the area. Particularly, the large numbers of dams and impoundments that have been built in the hydrographic basins have led a signi?cant reduction on river sediment loads. As a result, the Jonian littoral is experiencing a catalysed erosion phenomenon. In order to increase understanding of the morpho-dynamics of the Jonian littoral environment and more fully appreciate the amount of coastal erosion, an evaluation of the sediment budget change due to dam construction within the hydrographic basins of the Basilicata Region needs to be explored. Since quantitative data on decadal trends in river sediment supply before and after dam construction are lacking, as well as updated dam silting values, river basin assessment of the spatial patterns and estimated amount of sediment erosion and deposition are important in evaluating changes in the sediment budget. As coastal areas are being affected by an increasing number of population and socio-economic activities, the amount of sediment deficit at the littoral can permit to

  12. Low genetic diversity in pygmy blue whales is due to climate-induced diversification rather than anthropogenic impacts

    OpenAIRE

    Attard, Catherine R. M.; Luciano B Beheregaray; K Curt S Jenner; Gill, Peter C.; Jenner, Micheline-Nicole M.; Morrice, Margaret G.; Teske, Peter R; Möller, Luciana M.

    2015-01-01

    Unusually low genetic diversity can be a warning of an urgent need to mitigate causative anthropogenic activities. However, current low levels of genetic diversity in a population could also be due to natural historical events, including recent evolutionary divergence, or long-term persistence at a small population size. Here, we determine whether the relatively low genetic diversity of pygmy blue whales (Balaenoptera musculus brevicauda) in Australia is due to natural causes or overexploitat...

  13. Proteomic approaches to environmental stress in mussel Mytilus edulis due to emerging classes of anthropogenic pollutants

    OpenAIRE

    Jaafar, Siti NurTahirah

    2015-01-01

    Anthropogenic pollutant chemicals pose a major threat to aquatic organisms. There is a need for more research on emerging categories of environmental chemicals such as nanomaterials, endocrine disruptors and pharmaceuticals. Proteomics offers options and advantages for early warning of alterations in environmental quality by detecting sub-lethal changes in sentinel species such as the mussel, Mytilus edulis. This thesis aimed to compare the potential of traditional biomarkers (such as enzyme ...

  14. Planktic foraminiferal shell thinning in the Arabian Sea due to anthropogenic ocean acidification?

    Directory of Open Access Journals (Sweden)

    H. de Moel

    2009-02-01

    Full Text Available About one third of the anthropogenic carbon dioxide (CO2 released into the atmosphere in the past two centuries has been taken up by the ocean. As CO2 invades the surface ocean, carbonate ion concentrations and pH are lowered. Laboratory studies indicate that this reduces the calcification rates of marine calcifying organisms, including planktic foraminifera. Such a reduction in calcification resulting from anthropogenic CO2 emissions has not been observed, or quantified in the field yet. Here we present the findings of a study in the Western Arabian Sea that uses shells of the surface water dwelling planktic foraminifer Globigerinoides ruber in order to test the hypothesis that anthropogenically induced acidification has reduced shell calcification of this species. We found that light, thin-walled shells from the surface sediment are younger (based on 14C and δ13C measurements than the heavier, thicker-walled shells. Shells in the upper, bioturbated, sediment layer were significantly lighter compared to shells found below this layer. These observations are consistent with a scenario where anthropogenically induced ocean acidification reduced the rate at which foraminifera calcify, resulting in lighter shells. On the other hand, we show that seasonal upwelling in the area also influences their calcification and the stable isotope (δ13C and δ18O signatures recorded by the foraminifera shells. Plankton tow and sediment trap data show that lighter shells were produced during upwelling and heavier ones during non-upwelling periods. Seasonality alone, however, cannot explain the 14C results, or the increase in shell weight below the bioturbated sediment layer. We therefore must conclude that probably both the processes of acidification and seasonal upwelling are responsible for the presence of light shells in the top of the sediment and the age

  15. Planktic foraminiferal shell thinning in the Arabian Sea due to anthropogenic ocean acidification?

    Directory of Open Access Journals (Sweden)

    H. de Moel

    2009-09-01

    Full Text Available About one third of the anthropogenic carbon dioxide (CO2 released into the atmosphere in the past two centuries has been taken up by the ocean. As CO2 invades the surface ocean, carbonate ion concentrations and pH are lowered. Laboratory studies indicate that this reduces the calcification rates of marine calcifying organisms, including planktic foraminifera. Such a reduction in calcification resulting from anthropogenic CO2 emissions has not been observed, or quantified in the field yet. Here we present the findings of a study in the Western Arabian Sea that uses shells of the surface water dwelling planktic foraminifer Globigerinoides ruber in order to test the hypothesis that anthropogenically induced acidification has reduced shell calcification of this species. We found that light, thin-walled shells from the surface sediment are younger (based on 14C and δ13C measurements than the heavier, thicker-walled shells. Shells in the upper, bioturbated, sediment layer were significantly lighter compared to shells found below this layer. These observations are consistent with a scenario where anthropogenically induced ocean acidification reduced the rate at which foraminifera calcify, resulting in lighter shells. On the other hand, we show that seasonal upwelling in the area also influences their calcification and the stable isotope (δ13C and δ18O signatures recorded by the foraminifera shells. Plankton tow and sediment trap data show that lighter shells were produced during upwelling and heavier ones during non-upwelling periods. Seasonality alone, however, cannot explain the 14C results, or the increase in shell weight below the bioturbated sediment layer. We therefore must conclude that probably both the processes of acidification and seasonal upwelling are responsible for the presence of light shells in the top of the sediment and the age

  16. Changes in US background ozone due to global anthropogenic emissions from 1970 to 2020

    Science.gov (United States)

    Nopmongcol, Uarporn; Jung, Jaegun; Kumar, Naresh; Yarwood, Greg

    2016-09-01

    Estimates of North American and US Background (NAB and USB) ozone (O3) are critical in setting and implementing the US National Ambient Air Quality Standards (NAAQS) and therefore influence population exposure to O3 across the US. NAB is defined as the O3 concentration in the absence of anthropogenic O3 precursor emissions from North America whereas USB excludes anthropogenic emissions inside the US alone. NAB and USB vary geographically and with time of year. Analyses of O3 trends at rural locations near the west coast suggest that background O3 is rising in response to increasing non-US emissions. As the O3 NAAQS is lowered, rising background O3 would make attaining the NAAQS more difficult. Most studies of changing US background O3 have inferred trends from observations whereas air quality management decisions tend to rely on models. Thus, it is important that the models used to develop O3 management strategies are able to represent the changes in background O3 in order to increase confidence that air quality management strategies will succeed. We focus on how changing global emissions influence USB rather than the effects of inter-annual meteorological variation or long-term climate change. We use a regional model (CAMx) nested within a global model (GEOS-Chem) to refine our grid resolution over high terrain in the western US and near US borders where USB tends to be higher. We determine USB from CAMx simulations that exclude US anthropogenic emissions. Over five decades, from 1970 to 2020, estimated USB for the annual fourth highest maximum daily 8-h average O3 (H4MDA8) in the western US increased from mostly in the range of 40-55 ppb to 45-60 ppb, but remained below 45 ppb in the eastern US. USB increases in the southwestern US are consistent with rising emissions in Asia and Mexico. USB decreases in the northeast US after 1990 follow declining Canadian emissions. Our results show that the USB increases both for the top 30 MDA8 days and the H4MDA8 (the former

  17. Artificial breakwaters as garbage bins: Structural complexity enhances anthropogenic litter accumulation in marine intertidal habitats.

    Science.gov (United States)

    Aguilera, Moisés A; Broitman, Bernardo R; Thiel, Martin

    2016-07-01

    Coastal urban infrastructures are proliferating across the world, but knowledge about their emergent impacts is still limited. Here, we provide evidence that urban artificial reefs have a high potential to accumulate the diverse forms of litter originating from anthropogenic activities around cities. We test the hypothesis that the structural complexity of urban breakwaters, when compared with adjacent natural rocky intertidal habitats, is a driver of anthropogenic litter accumulation. We determined litter abundances at seven sites (cities) and estimated the structural complexity in both urban breakwaters and adjacent natural habitats from northern to central Chile, spanning a latitudinal gradient of ∼15° (18°S to 33°S). Anthropogenic litter density was significantly higher in coastal breakwaters when compared to natural habitats (∼15.1 items m(-2) on artificial reefs versus 7.4 items m(-2) in natural habitats) at all study sites, a pattern that was temporally persistent. Different litter categories were more abundant on the artificial reefs than in natural habitats, with local human population density and breakwater extension contributing to increase the probabilities of litter occurrence by ∼10%. In addition, structural complexity was about two-fold higher on artificial reefs, with anthropogenic litter density being highest at intermediate levels of structural complexity. Therefore, the spatial structure characteristic of artificial reefs seems to enhance anthropogenic litter accumulation, also leading to higher residence time and degradation potential. Our study highlights the interaction between coastal urban habitat modification by establishment of artificial reefs, and pollution. This emergent phenomenon is an important issue to be considered in future management plans and the engineering of coastal ecosystems. PMID:27149151

  18. Nonlinear effect on the East Asian summer monsoon due to two coexisting anthropogenic forcing factors in eastern China: an AGCM study

    Science.gov (United States)

    Deng, Jiechun; Xu, Haiming

    2016-06-01

    Two anthropogenic forcing factors dominate in eastern China: aerosols and urban land cover. Usually, aerosols induce surface cooling while urban land cover causes surface warming. It is important to explore whether or not a nonlinear effect may result from the coexistence of these two opposing effects, and to what extent such nonlinear effect may become significant in affecting the climate change in East Asia. In this study, the Community Atmosphere Model version 5.1 (CAM5.1) coupled with the Community Land Model version 4 (CLM4) is employed to investigate the nonlinear effect on the East Asian summer monsoon due to the coexistence of aerosols and urban land cover. The anthropogenic forcing can be studied by including only aerosol emissions, only urban land cover, or a combination of the two in eastern China. The nonlinear effect obtained in CAM5.1 is evident in eastern China to offset the urbanization effect. Large-scale atmospheric response produces anomalous upward motion and increases total cloud amount and precipitation. This increased total cloud amount and its associated negative shortwave cloud forcing in turn significantly decrease surface air temperature and cool the troposphere, especially in northern China, resulting in a reduced land-sea thermal contrast, which acts to weaken the prevailing southwesterly wind over the Yangtze River Valley and southwestern China and to enhance the wind over the northern South China Sea. The nonlinear effect also indirectly excites strong convection over southern China, leading to a pronounced increase in summer precipitation.

  19. Reduced sediment transport in the Yellow River due to anthropogenic changes

    Science.gov (United States)

    Wang, Shuai; Fu, Bojie; Piao, Shilong; Lü, Yihe; Ciais, Philippe; Feng, Xiaoming; Wang, Yafeng

    2016-01-01

    The erosion, transport and redeposition of sediments shape the Earth’s surface, and affect the structure and function of ecosystems and society. The Yellow River was once the world’s largest carrier of fluvial sediment, but its sediment load has decreased by approximately 90% over the past 60 years. The decline in sediment load is due to changes in water discharge and sediment concentration, which are both influenced by regional climate change and human activities. Here we use an attribution approach to analyse 60 years of runoff and sediment load observations from the traverse of the Yellow River over China’s Loess Plateau -- the source of nearly 90% of its sediment load. We find that landscape engineering, terracing and the construction of check dams and reservoirs were the primary factors driving reduction in sediment load from the 1970s to 1990s, but large-scale vegetation restoration projects have also reduced soil erosion from the 1990s onwards. We suggest that, as the ability of existing dams and reservoirs to trap sediments declines in the future, erosion rates on the Loess Plateau will increasingly control the Yellow River’s sediment load.

  20. Low genetic diversity in pygmy blue whales is due to climate-induced diversification rather than anthropogenic impacts.

    Science.gov (United States)

    Attard, Catherine R M; Beheregaray, Luciano B; Jenner, K Curt S; Gill, Peter C; Jenner, Micheline-Nicole M; Morrice, Margaret G; Teske, Peter R; Möller, Luciana M

    2015-05-01

    Unusually low genetic diversity can be a warning of an urgent need to mitigate causative anthropogenic activities. However, current low levels of genetic diversity in a population could also be due to natural historical events, including recent evolutionary divergence, or long-term persistence at a small population size. Here, we determine whether the relatively low genetic diversity of pygmy blue whales (Balaenoptera musculus brevicauda) in Australia is due to natural causes or overexploitation. We apply recently developed analytical approaches in the largest genetic dataset ever compiled to study blue whales (297 samples collected after whaling and representing lineages from Australia, Antarctica and Chile). We find that low levels of genetic diversity in Australia are due to a natural founder event from Antarctic blue whales (Balaenoptera musculus intermedia) that occurred around the Last Glacial Maximum, followed by evolutionary divergence. Historical climate change has therefore driven the evolution of blue whales into genetically, phenotypically and behaviourally distinct lineages that will likely be influenced by future climate change. PMID:25948571

  1. Declines in Soil pH due to Anthropogenic Nitrogen Inputs Alter Buffering and Exchange Reactions in Tropical Forest Soils

    Science.gov (United States)

    Lohse, K. A.

    2003-12-01

    Anthropogenic nitrogen (N) inputs may alter tropical soil buffering and exchange reactions that have important implications for nutrient cycling, forest productivity, and downstream ecosystems. In contrast to relatively young temperate soils that are typically buffered from N inputs by base cation reactions, aluminum reactions may serve to buffer highly weathered tropical soils and result in immediate increases in aluminum mobility and toxicity. Increased nitrate losses due to chronic N inputs may also deplete residual base cations in already weathered base cation-poor soils, further acidify soils, and thereby reduce nitrate mobility through pH-dependent anion exchange reactions. To test these hypotheses, I determined soil pH and cation and anion exchange capacity (CEC and AEC) and measured base cation and aluminum soil solution losses following first-time and long-term experimental N additions from two Hawaiian tropical forest soils, a 300 year old Andisol and a 4.1 million year old Oxisol. I found that elevated base cation losses accompanied increased nitrate losses after first time N additions to the young Andisol whereas immediate and large aluminum losses were associated with increased nitrate losses from the Oxisol. In the long-term, base cation and aluminum losses increased in proportion to nitrate losses. Long-term N additions at both sites resulted in significant declines in soil pH, decreased CEC and increased AEC. These results suggest that even chronic N inputs resulting in small but elevated nitrate losses may deplete residual base cations, increase mobility and toxicity of aluminum, and potentially lead to declines in forest productivity and acidification of downstream ecosystems. These findings also suggest that AEC may provide a long-term mechanism to delay nitrate losses in tropical forests with significant variable charge that are experiencing chronic anthropogenic N inputs.

  2. Long-term persistence enhances uncertainty about anthropogenic warming of Antarctica

    Science.gov (United States)

    Ludescher, Josef; Bunde, Armin; Franzke, Christian L. E.; Schellnhuber, Hans Joachim

    2016-01-01

    Previous estimates of the strength and the uncertainty of the observed Antarctic temperature trends assumed that the natural annual temperature fluctuations can be represented by an auto-regressive process of first order [AR(1)]. Here we find that this hypothesis is inadequate. We consider the longest observational temperature records in Antarctica and show that their variability is better represented by a long-term persistent process that has a propensity of large and enduring natural excursions from the mean. As a consequence, the statistical significance of the recent (presumably anthropogenic) Antarctic warming trend is lower than hitherto reported, while the uncertainty about its magnitude is enhanced. Indeed, all records except for one (Faraday/Vernadsky) fail to show a significant trend. When increasing the signal-to-noise ratio by considering appropriate averages of the local temperature series, we find that the warming trend is still not significant in East Antarctica and the Antarctic Peninsula. In West Antarctica, however, the significance of the trend is above 97.4 %, and its magnitude is between 0.08 and 0.96 °C per decade. We argue that the persistent temperature fluctuations not only have a larger impact on regional warming uncertainties than previously thought but also may provide a potential mechanism for understanding the transient weakening ("hiatus") of the regional and global temperature trends.

  3. Estimating changes in carbon burial on the western US coastal shelf due to anthropogenic influences on river exports

    Science.gov (United States)

    Sauer, M.; Bergamaschi, B. A.; Smith, R. A.; Zhu, Z.; Shih, J.

    2012-12-01

    Flux of nutrients and sediments to the coastal zone varies in response to land-use modification, reservoir construction, management action and population change. It is anticipated that future changes in the flux of these components in response to climate and terrestrial processes will affect carbon (C) burial in the coastal ocean. Coastal oceans store appreciable amounts of C as a result of river inflows: coastal primary production is enhanced by inputs of terrestrially derived nutrients, and C burial is controlled by terrestrial sediment supply. Assessing the capacity and changes to coastal C preservation, therefore, requires estimation of (1) riverine nutrient and sediment delivery to the coastal ocean, and (2) the enhanced C production and sediment deposition in the coastal ocean. The United States Geological Survey (USGS) has embarked on a congressionally-mandated nationwide effort to assess the future effects of climate and land use and land cover change (LULC) on C storage. The USGS has developed alternative scenarios for changes in US LULC from 2006 to 2100 based on the Intergovernmental Panel on Climate Change (IPCC) climate, economic, and demographic scenarios (Sohl et al 2012). These spatially-detailed scenarios provide inputs to national-scale SPARROW watershed models of total nitrogen, total phosphorus, total organic C (TOC), and suspended sediment (Smith et al 1997; Schwarz et al, 2006). The watershed models, in turn, provide inputs of nutrients, TOC, and sediment to a coupled model of coastal transport, production, and sedimentation. This coastal modelling component includes particulate C sedimentation and burial estimated as functions of bathymetry and pycnocline depth (Armstrong, et al 2002; Dunne et al 2007). River borne fluxes of TOC to US Pacific coastal waters under baseline conditions (1992) were 1.59 TgC/yr. Projected future (2050) fluxes under a regionally-downscaled LULC scenario aligned with the IPCC A2 scenario were similar (1.61TgC/yr). C

  4. Radionuclides in the environment in the south of Spain, anthropogenic enhancements due to industry

    Energy Technology Data Exchange (ETDEWEB)

    Manjon, G. [Depto. de Fisica Aplicada 2, E.T.S. Arquitectura, Universidad de Sevilla, Av. Reina Mercedes 2, 41012 - Sevilla (Spain)

    2007-07-01

    Levels of natural radionuclides in the environment are affected by human activities in the South of Spain. Industry wastes, such as phospho-gypsum, have been released to an estuary since sixties until 1997. Nowadays the wastes management is careful with environment protection, which can be clearly observed today in the radionuclides pattern. Different sources of radionuclides (industry wastes, tidal action and mining) can be distinguished in the estuary. Uranium isotopes, {sup 226}Ra, {sup 210}Pb and {sup 210}Po were determined in water and sediment samples for this study. An iron recycling factory is working close to Seville (South of Spain). A {sup 137}Cs source was accidentally burnt in a furnace of this factory in 2001. The environmental impact of this accident was immediately denatured. Monitoring procedure and results are sho vn in this contribution. Radionuclides measurement involves difficult techniques. In this communication a procedure to determine the activity concentration of {sup 210}Pb by liquid scintillation counting is presented. Two quality tests, using gamma- and alpha-spectrometry were applied to the {sup 210} Pb results. (Author)

  5. Radionuclides in the environment in the south of Spain, anthropogenic enhancements due to industry

    International Nuclear Information System (INIS)

    Levels of natural radionuclides in the environment are affected by human activities in the South of Spain. Industry wastes, such as phospho-gypsum, have been released to an estuary since sixties until 1997. Nowadays the wastes management is careful with environment protection, which can be clearly observed today in the radionuclides pattern. Different sources of radionuclides (industry wastes, tidal action and mining) can be distinguished in the estuary. Uranium isotopes, 226Ra, 210Pb and 210Po were determined in water and sediment samples for this study. An iron recycling factory is working close to Seville (South of Spain). A 137Cs source was accidentally burnt in a furnace of this factory in 2001. The environmental impact of this accident was immediately denatured. Monitoring procedure and results are sho vn in this contribution. Radionuclides measurement involves difficult techniques. In this communication a procedure to determine the activity concentration of 210Pb by liquid scintillation counting is presented. Two quality tests, using gamma- and alpha-spectrometry were applied to the 210 Pb results. (Author)

  6. Reorganization of a large marine ecosystem due to atmospheric and anthropogenic pressure: a discontinuous regime shift in the Central Baltic Sea

    DEFF Research Database (Denmark)

    Moellmann, C; Diekmann, Rabea; Muller-Karulis, B;

    2009-01-01

    Marine ecosystems such as the Baltic Sea are currently under strong atmospheric and anthropogenic pressure. Besides natural and human-induced changes in climate, major anthropogenic drivers such as overfishing and anthropogenic eutrophication are significantly affecting ecosystem structure...

  7. Enhancement of parametric pumping due to Andreev reflection

    OpenAIRE

    Wei, Y.; Wang, B.; Guo, H; Wang, J

    2001-01-01

    We report properties of parametric electron pumping in the presence of a superconducting lead. Due to a constructive interference between the direct reflection and the multiple Andreev reflection, the pumped current is greatly enhanced. For both quantum point contacts and double barrier structures at resonance, we obtain exact solutions in the weak pumping regime showing that I = 4I, which should be compared with the result of conductance GNS = 2GN. Numerical results are also provided for the...

  8. Enhanced J/$\\psi$ suppression due to gluon depletion

    CERN Document Server

    Hwa, R C; Pisútová, N

    1998-01-01

    The nonlinear effect of gluon depletion in the collision of large nuclei can be large. It is due to multiple scatterings among comoving partons initiated by primary scattering of partons in the colliding nuclei. The effect can give rise to substantial suppression of $J/\\psi$ production in very large nuclei, even if the linear depletion effect is insignificant for the collisions of nuclei of smaller sizes. This mechanism offers a natural explanation of the enhanced suppression in the Pb-Pb data recently observed by NA50.

  9. Assurance of risk assessment and protection distant transportation and fall out of pollutants under large anthropogenic on nuclear power stations due to mountainous regional peculiarities

    International Nuclear Information System (INIS)

    Full text: All types of industrial activities require the norms of protection, assessment of corresponding risks to preserve the pollution and degradation of corresponding areas. To make available the sustainable development of the country the risk assessment of possible accidents on the big enterprises is foreseen that provides preparedness of the country and possibility of the prevention measures and mitigation of the accidents. While big anthropogenic accidents in mountainous countries - the main paths for transportation of the pollution are the rivers and sea basins. Due to overpopulation of these areas assessment of the pollution risks are very important. Problem of forecast and distant atmospheric transportation of the toxic products and corresponding risk assessment under anthropogenic damages is multi-component and depends on meteorological conditions and frontier layer of atmosphere. Generally, for real relief and basic fields the problem is not solved yet especially taking into consideration the big level and shortest time of the process being of the natural anthropogenic accidents in mountainous regions. Usually, geostropic drawing for determined relief is used. Integral differential equations taking into consideration a physical- chemical characteristic of the pollutants, their transformations, fall out, coagulations, washing out and self rectification in general cannot be solved. In last time essential success in formalization of above-mentioned equations i.e. carrying out some simplifications give possibility to establish necessary modeling on the basis of numerical calculations. In the most general case forecasting model is essentially limited because of bulky size of accounting schemes and necessity of powerful and high-speed computers. Main ways of achievement of further success is connected with so called 'seasonal typification' with applied a priory calculation of probabilistic picture of the pollutants concentration fields, as well as

  10. Statistical analyses for the purpose of an early detection of global and regional climate change due to the anthropogenic greenhouse effect; Statistische Analysen zur Frueherkennung globaler und regionaler Klimaaenderungen aufgrund des anthropogenen Treibhauseffektes

    Energy Technology Data Exchange (ETDEWEB)

    Grieser, J.; Staeger, T.; Schoenwiese, C.D.

    2000-03-01

    The report answers the question where, why and how different climate variables have changed within the last 100 years. The analyzed variables are observed time series of temperature (mean, maximum, minimum), precipitation, air pressure, and water vapour pressure in a monthly resolution. The time series are given as station data and grid box data as well. Two kinds of time-series analysis are performed. The first is applied to find significant changes concerning mean and variance of the time series. Thereby also changes in the annual cycle and frequency of extreme events arise. The second approach is used to detect significant spatio-temporal patterns in the variations of climate variables, which are most likely driven by known natural and anthropogenic climate forcings. Furtheron, an estimation of climate noise allows to indicate regions where certain climate variables have changed significantly due to the enhanced anthropogenic greenhouse effect. (orig.) [German] Der Bericht gibt Antwort auf die Frage, wo sich welche Klimavariable wie und warum veraendert hat. Ausgangspunkt der Analyse sind huntertjaehrige Zeitreihen der Temperatur (Mittel, Maximum, Minimum), des Niederschlags, Luftdrucks und Wasserdampfpartialdrucks in monatlicher Aufloesung. Es wurden sowohl Stationsdaten als auch Gitterpunktdaten verwendet. Mit Hilfe der strukturorientierten Zeitreihenzerlegung wurden signifikankte Aenderungen im Mittel und in der Varianz der Zeitreihen gefunden. Diese betreffen auch Aenderungen im Jahresgang und in der Haeufigkeit extremer Ereignisse. Die ursachenorientierte Zeitreihenzerlegung selektiert signifikante raumzeitliche Variationen der Klimavariablen, die natuerlichen bzw. anthropogenen Klimaantrieben zugeordnet werden koennen. Eine Abschaetzung des Klimarauschens erlaubt darueber hinaus anzugeben, wo und wie signifikant der anthropogene Treibhauseffekt welche Klimavariablen veraendert hat. (orig.)

  11. Anthropogenic wetlands due to over-irrigation of desert areas; A challenging hydrogeological investigation with extensive geophysical input

    Science.gov (United States)

    Behroozmand, A. A.; Teatini, P.; Pedersen, J. B. B.; Auken, E.; Tosatto, O.; Christiansen, A. V.

    2015-12-01

    During the last century, many large irrigation projects have been initiated in arid lands worldwide. Despite a tremendous increase in food production, a common problem when characterizing these zones is land degradation in form of waterlogging. As results, large volumes of water are lost due to surplus irrigation in regions where water availability is extremely challenging for both population survival and economic development. The Nubariya depression, Western Desert (Egypt), is a clear example of this mechanism. Following the reclamation of desert lands for agricultural production, an artificial brackish and contaminated lake developed in the area in the late 1990s and presently extends for about 2.5 km2. Available data provide evidence of a simultaneous general deterioration of the groundwater system. With the main objectives of understanding the hydrological evolution of the area, characterizing the hydrogeological setting and developing scenarios for artificial aquifer remediation and recharge, an extensive hydrogeophysical investigation was carried out in this challenging environment using Magnetic Resonance Sounding (MRS, also called surface NMR) and ground-based Transient EM (TEM). The integrated interpretation of the geophysical surveys, properly calibrated with a number of boreholes, provides a clear hydrogeological picture of the upper 100 m sedimentary structure, in terms of both lithology and groundwater quality. The information is then used to set up a regional groundwater flow and a local density-dependent flow and transport numerical model to reproduce the past evolution of the aquifer system and develop a few scenarios for artificial aquifer recharge using the treated waters provided by a nearby waste-water treatment plant. The research outcomes point the hydrological challenges that emerge for an effective management of water resources in reclaimed desert areas and highlight the effectiveness of integrating advanced geophysical and modeling

  12. Enhancement in secondary particulate matter production due to mountain trapping

    Science.gov (United States)

    Yao, Teng; Fung, J. C. H.; Ma, H.; Lau, A. K. H.; Chan, P. W.; Yu, J. Z.; Xue, J.

    2014-10-01

    As China's largest economic development zone, the Pearl River Delta (PRD) is subject to particulate matter (PM) and visibility deterioration problems. Due to high PM concentration, haze days impacting ambient visibility have occurred frequently in this region. Besides visibility impairment, PM pollution also causes a negative impact on public health. These negative impacts have heightened the need to improve our understanding of the PM pollution of the PRD region. One major cause of the PRD pollution problem is cold front passages in the winter; however, the mechanism of pollution formation stays unclear. In this study, the Comprehensive Air Quality Model (CAMx) is utilized to investigate the detailed PM production and transport mechanisms in the PRD. Simulated concentrations of PM2.5 species, which have a good correlation with observation, show that sulfate and nitrate are the dominant pollutants among different PM2.5 species. Before the cold front passage a large amount of gas-phase and particle-phase pollutants are transported to the mountainous regions in the north of the PRD, and become trapped by the terrain. Over the mountain regions, cloud driven by upwelling flow promotes aqueous-phase reactions including oxidations of PM precursors such as SO2 and NO2. By this process, production of secondary PM is enhanced. When the cold front continues to advance further south, PM is transported to the PRD cities, and suppressed into a thin layer near the ground by a low planetary boundary layer (PBL). Thus high PM concentration episodes take place in the PRD cities. After examining production and transportation pathways, this study presents that the complex terrain configuration would block pollutant dispersion, provide cloudy environment, and advance secondary PM production. Previous studies have pointed out that pollution emitted from outside this region largely influences the air quality in the PRD; however, this study shows that pollutants from the outside could be

  13. Noise enhancement due to quantum coherence in coupled quantum dots

    OpenAIRE

    Kiesslich, G.; Schoell, E.; Brandes, T.; Hohls, F.; Haug, R. J.

    2007-01-01

    We show that the intriguing observation of noise enhancement in the charge transport through two vertically coupled quantum dots can be explained by the interplay of quantum coherence and strong Coulomb blockade. We demonstrate that this novel mechanism for super-Poissonian charge transfer is very sensitive to decoherence caused by electron-phonon scattering as inferred from the measured temperature dependence.

  14. Tectonic earthquakes of anthropogenic origin

    Science.gov (United States)

    Adushkin, V. V.

    2016-03-01

    The enhancement of seismicity induced by industrial activity in Russia in the conditions of present-day anthropization is noted. In particular, the growth in the intensity and number of strong tectonic earthquakes with magnitudes M ≥ 3 (seismic energy 109 J) due to human activity is revealed. These man-made tectonic earthquakes have started to occur in the regions of the East European Platform which were previously aseismic. The development of such seismicity is noted in the areas of intense long-term mineral extraction due to the increasing production depth and extended mining and production. The mechanisms and generation conditions of man-made tectonic earthquakes in the anthropogenically disturbed medium with the changed geodynamical and fluid regime is discussed. The source zones of these shallow-focus tectonic earthquakes of anthropogenic origin are formed in the setting of stress state rearrangement under anthropogenic loading both near these zones and at a significant distance from them. This distance is determined by the tectonic structure of the rock mass and the character of its energy saturation, in particular, by the level of the formation pressure or pore pressure. These earthquakes occur at any time of the day, have a triggered character, and are frequently accompanied by catastrophic phenomena in the underground mines and on the surface due to the closeness to the source zones.

  15. Does availability of anthropogenic food enhance densities of omnivorous mammals? An example with coyotes in southern California

    OpenAIRE

    Fedriani, José M.; Fuller, Todd K.; Sauvajot, Raymond M.

    2001-01-01

    To evaluate whether the abundance of coyotes Canis latrans was influenced by the availability of anthropogenic foods in a humanized landscape, we compared three neighboring areas (hereafter referred to as NA, CA, and SA) under contrasting human pressures within the Santa Monica Mountains of California, USA. We quantified the use of anthropogenic foods by coyotes and assessed local densities within these three regions. Overall, 761 coyote feces were...

  16. Enhanced diffusion due to active swimmers at a solid surface

    CERN Document Server

    Miño, Gaston; Darnige, Thierry; Hoyos, Mauricio; Dauchet, Jeremy; Dunstan, Jocelyn; Soto, Rodrigo; Wang, Yang; Rousselet, Annie; Clement, Eric

    2010-01-01

    We consider two systems of active swimmers moving close to a solid surface, one being a living population of wild-type \\textit{E. coli} and the other being an assembly of self-propelled Au-Pt rods. In both situations, we have identified two different types of motion at the surface and evaluated the fraction of the population that displayed ballistic trajectories (active swimmers) with respect to those showing random-like behavior. We studied the effect of this complex swimming activity on the diffusivity of passive tracers also present at the surface. We found that the tracer diffusivity is enhanced with respect to standard Brownian motion and increases linearly with the activity of the fluid, defined as the product of the fraction of active swimmers and their mean velocity. This result can be understood in terms of series of elementary encounters between the active swimmers and the tracers.

  17. The detection of climate change due to the enhanced greenhouse effect

    Science.gov (United States)

    Schiffer, Robert A.; Unninayar, Sushel

    1991-01-01

    The greenhouse effect is accepted as an undisputed fact from both theoretical and observational considerations. In Earth's atmosphere, the primary greenhouse gas is water vapor. The specific concern today is that increasing concentrations of anthropogenically introduced greenhouse gases will, sooner or later, irreversibly alter the climate of Earth. Detecting climate change has been complicated by uncertainties in historical observations and measurements. Thus, the primary concern for the GEDEX project is how can climate change and enhanced greenhouse effects be unambiguously detected and quantified. Specifically examined are the areas of: Earth surface temperature; the free atmosphere (850 millibars and above); space-based measurements; measurement uncertainties; and modeling the observed temperature record.

  18. Measurement of resuspended aerosol in the Chernobyl area. Pt. III. Size distribution and dry deposition velocity of radioactive particles during anthropogenic enhanced resuspension

    International Nuclear Information System (INIS)

    During anthropogenic activities, such as agricultural soil management and traffic on unpaved roads, size distribution measurements were performed of atmospheric particulate radionuclides at a site in the Chernobyl 30-km exclusion zone. Analysis of cascade impactor measurements showed an increase of the total atmospheric radioactivity. In the cases of harrowing by a tractor and traffic on unpaved roads, a common shape of the size distribution was found with two maxima, the first in the 2-4 μm range, the second in the 12-20 μm range. The size distributions were compared to measurements during wind-driven resuspension. Particle number concentration measurements with an Aerodynamic Particle Sizer showed a dynamic dependence of the particle concentration in different size ranges on anthropogenic action. The increase of the mean concentration was for the large particles more than one order of magnitude higher than for fine particles during anthropogenic enhanced resuspension. From the measurement of the mass concentration, the radioactive loading could be estimated. An enrichment of radionuclides on resuspended particles (compared to soil particles) was found, with the highest enrichment for large particles. Micrometeorological considerations showed that large particles may frequently be subject to medium range transport. The dry deposition velocity was measured; the mean value of 0.026 m s-1±0.016 m s-1 is typical for 6-9 μm diameter particles. (orig.)

  19. Variability assessment of metals distributions due to anthropogenic and geogenic impact in the lead-zinc mine and flotation 'Zletovo' environs (moss bio monitoring)

    International Nuclear Information System (INIS)

    Moss species ( Hypnum cupressiforme , Scleropodium purum and Campthotecium lutescens ) were used as suitable sampling media for bio monitoring the origin of heavy metal pollution in the lead-zinc mine and flotation environ near the town of Probishtip. The 21 metals contents were determined by atomic emission spectrometry with inductively coupled plasma (ICP-AES). Data processing was applied with combinations of multivariate statistical methods: factor analysis, principal component analysis and cluster analysis. The main anthropogenic markers in the investigated area were Pb and Zn (maximal values of 200 and 186 mg kg-1 , respectively). The factor analysis singled out (in the increasing scale) the following associations: F1/D1: Fe < Mo < Pb < Na < Cd < Mg < Zn < Ag < Cu and F2/D2: Mn < Ni < K < P < Ba < Sr < Ca < As < Cr < Al < V < Li. The anthropogenic elements contents vary independent from the moss species, but depending on the distancing from the pollution source, there are positive correlation. Long distance distribution from the emission source doesn't occur. (Author)

  20. Aerosol light-scattering enhancement due to water uptake during TCAP campaign

    Directory of Open Access Journals (Sweden)

    G. Titos

    2014-02-01

    Full Text Available Aerosol optical properties were measured by the DOE/ARM (US Department of Energy Atmospheric Radiation Measurements Program Mobile Facility in the framework of the Two-Column Aerosol Project (TCAP deployed at Cape Cod, Massachusetts, for a~one year period (from summer 2012 to summer 2013. Measured optical properties included aerosol light-absorption coefficient (σap at low relative humidity (RH and aerosol light-scattering coefficient (σsp at low and at RH values varying from 30 to 85%, approximately. Calculated variables included the single scattering albedo (SSA, the scattering Ångström exponent (SAE and the scattering enhancement factor (f(RH. Over the period of measurement, f(RH = 80% had a mean value of 1.9 ± 0.3 and 1.8 ± 0.4 in the PM10 and PM1 fractions, respectively. Higher f(RH = 80% values were observed for wind directions from 0–180° (marine sector together with high SSA and low SAE values. The wind sector from 225 to 315° was identified as an anthropogenically-influenced sector, and it was characterized by smaller, darker and less hygroscopic aerosols. For the marine sector, f(RH = 80% was 2.2 compared with a value of 1.8 obtained for the anthropogenically-influenced sector. The air-mass backward trajectory analysis agreed well with the wind sector analysis. It shows low cluster to cluster variability except for air-masses coming from the Atlantic Ocean that showed higher hygroscopicity. Knowledge of the effect of RH on aerosol optical properties is of great importance for climate forcing calculations and for comparison of in-situ measurements with satellite and remote sensing retrievals. In this sense, predictive capability of f(RH for use in climate models would be enhanced if other aerosol parameters could be used as proxies to estimate hygroscopic growth. Toward this goal, we propose an exponential equation that successfully estimates aerosol hygroscopicity as a function of SSA at Cape Cod. Further work is needed to

  1. Future premature mortality due to O3, secondary inorganic aerosols and primary PM in Europe - sensitivity to changes in climate, anthropogenic emissions, population and building stock

    OpenAIRE

    Camilla Geels; Camilla Andersson; Otto Hänninen; Anne Sofie Lansø; Schwarze, Per E; Carsten Ambelas Skjøth; Jørgen Brandt

    2015-01-01

    Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensiti...

  2. Changes in severe thunderstorm environment frequency during the 21st century caused by anthropogenically enhanced global radiative forcing

    OpenAIRE

    Trapp, Robert J.; Diffenbaugh, Noah S.; Brooks, Harold E.; Baldwin, Michael E.; Robinson, Eric D.; Pal, Jeremy S.

    2007-01-01

    Severe thunderstorms comprise an extreme class of deep convective clouds and produce high-impact weather such as destructive surface winds, hail, and tornadoes. This study addresses the question of how severe thunderstorm frequency in the United States might change because of enhanced global radiative forcing associated with elevated greenhouse gas concentrations. We use global climate models and a high-resolution regional climate model to examine the larger-scale (or “environmental”) meteoro...

  3. Future Premature Mortality Due to O3, Secondary Inorganic Aerosols and Primary PM in Europe — Sensitivity to Changes in Climate, Anthropogenic Emissions, Population and Building Stock

    Directory of Open Access Journals (Sweden)

    Camilla Geels

    2015-03-01

    Full Text Available Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000–2009, 2050–2059 and 2080–2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future.

  4. Photoluminescence intensity enhancement in SWNT aqueous suspensions due to reducing agent doping: Influence of adsorbed biopolymer

    Science.gov (United States)

    Kurnosov, N. V.; Leontiev, V. S.; Linnik, A. S.; Lytvyn, O. S.; Karachevtsev, V. A.

    2014-06-01

    The influence of biopolymer wrapped around nanotube on the enhancement of the semiconducting single-walled carbon nanotube (SWNT) photoluminescence (PL) in aqueous suspension which increases due to the reducing agent dithiothreitol (DTT) doping effect was revealed. The greatest enhancement of PL was observed for SWNTs covered with double- or single stranded DNA (above 170%) and DTT weak influence was revealed for SWNTs:polyC suspension (∼45%). The magnitude of the PL enhancement depends also on nanotube chirality and sample aging. The behavior of PL from SWNTs covered with various polymers is explained by the different biopolymers ordering on the nanotube surface. The ordered polymer conformation on the nanotube weakens the reducing agent doping effect. The method of reducing agent doping of nanotube:biopolymer aqueous suspension can serve as a sensitive luminescent probe of the biopolymer ordering on the carbon nanotube and can be used to increase the sensitivity of luminescent biosensors.

  5. Numerical study on the effective heating due to inertial cavitation in microbubble-enhanced HIFU therapy

    Science.gov (United States)

    Okita, Kohei; Sugiyama, Kazuyasu; Takagi, Shu; Matsumoto, Yoichiro

    2015-10-01

    The enhancement of heating due to inertial cavitation was focused in high-intensity focused ultrasound (HIFU) therapy. The influences of the rectified diffusion on microbubble-enhanced HIFU were examined numerically. A bubble dynamics equation in consideration of the spherical shell bubble and the elasticity of surrounding tissue was employed. Mass and heat transfer between the surrounding medium and the bubble were considered. The basic equations were discretized by finite difference method. The mixture phase and bubbles are coupled by the Euler-Lagrange method to take into account the interaction between ultrasound and bubbles. The mass transfer rate of gas from the surrounding medium to the bubble was examined as function of the initial bubble radius and the driving pressure amplitude. As the results, the pressure required to bubble growth was decreases with increasing the initial bubble radius. Thus, the injection of microbubble reduces the cavitation threshold pressure. On the other hand, the influence of the rectified diffusion on the triggered HIFU therapy which generates cavitation bubbles by high-intensity burst and induces the localized heating owing to cavitation bubble oscillation by low-intensity continuous waves. The calculation showed that the localized heating was enhanced by the increase of the equilibrium bubble size due to the rectified diffusion.

  6. Enhancement of transport properties of a Brownian particle due to quantum effects: Smoluchowski limit

    International Nuclear Information System (INIS)

    Graphical abstract: By invoking physically motivated coordinate transformation into quantum Smoluchowski equation, we have presented a transparent treatment for the determination of the effective diffusion coefficient and current of a quantum Brownian particle. Substantial enhancement in the efficiency of the diffusive transport is envisaged due to the quantum correction effects. Highlights:: ► Transport of a quantum Brownian particle in a periodic potential has been addressed. ► Governing quantum Smoluchowski equation (QSE) includes state dependent diffusion. ► A coordinate transformation is used to recast QSE with constant diffusion. ► Transport properties increases in comparison to the corresponding classical result. ► This enhancement is purely a quantum effect. - Abstract: The transport property of a quantum Brownian particle that interacts strongly with a bath (in which a typical damping constant by far exceeds a characteristic frequency of the isolated system) under the influence of a tilted periodic potential has been studied by solving quantum Smoluchowski equation (QSE). By invoking physically motivated coordinate transformation into QSE, we have presented a transparent treatment for the determination of the effective diffusion coefficient of a quantum Brownian particle and the current (the average stationary velocity). Substantial enhancement in the efficiency of the diffusive transport is envisaged due to the quantum correction effects only if the bath temperature hovers around an appropriate range of intermediate values. Our findings also confirm the results obtained in the classical cases.

  7. Enhancement of transport properties of a Brownian particle due to quantum effects: Smoluchowski limit

    Energy Technology Data Exchange (ETDEWEB)

    Shit, Anindita [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Chattopadhyay, Sudip, E-mail: sudip_chattopadhyay@rediffmail.com [Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Chaudhuri, Jyotipratim Ray, E-mail: jprc_8@yahoo.com [Department of Physics, Katwa College, Katwa, Burdwan 713130 (India)

    2012-03-13

    Graphical abstract: By invoking physically motivated coordinate transformation into quantum Smoluchowski equation, we have presented a transparent treatment for the determination of the effective diffusion coefficient and current of a quantum Brownian particle. Substantial enhancement in the efficiency of the diffusive transport is envisaged due to the quantum correction effects. Highlights:: Black-Right-Pointing-Pointer Transport of a quantum Brownian particle in a periodic potential has been addressed. Black-Right-Pointing-Pointer Governing quantum Smoluchowski equation (QSE) includes state dependent diffusion. Black-Right-Pointing-Pointer A coordinate transformation is used to recast QSE with constant diffusion. Black-Right-Pointing-Pointer Transport properties increases in comparison to the corresponding classical result. Black-Right-Pointing-Pointer This enhancement is purely a quantum effect. - Abstract: The transport property of a quantum Brownian particle that interacts strongly with a bath (in which a typical damping constant by far exceeds a characteristic frequency of the isolated system) under the influence of a tilted periodic potential has been studied by solving quantum Smoluchowski equation (QSE). By invoking physically motivated coordinate transformation into QSE, we have presented a transparent treatment for the determination of the effective diffusion coefficient of a quantum Brownian particle and the current (the average stationary velocity). Substantial enhancement in the efficiency of the diffusive transport is envisaged due to the quantum correction effects only if the bath temperature hovers around an appropriate range of intermediate values. Our findings also confirm the results obtained in the classical cases.

  8. Enhancement of the isovector M1 strength in 28Si due to meson exchange currents

    International Nuclear Information System (INIS)

    Meson exchange currents (MEC close-quote s) can induce an enhancement of the B(M1) strength in nuclei over the corresponding Gamow-Teller strength. Such an increase was observed in 28Si [C. Luettge et al., Phys. Rev. C 53, 127 (1996)], but the experimental ratio was much larger than shell model predictions using the unified sd-shell interaction and corrections to the g factors which incorporate MEC effects. It is pointed out that, when taking the Gamow-Teller strength from a reanalysis of the 28Si(p,n) data as well as from a recent 28Si(3He,t) experiment, the derived ratio is now in good agreement with the shell model results. This finding provides strong support that the observed enhancement is due to meson exchange currents. copyright 1997 The American Physical Society

  9. Copper alloys deterioration due to anthropogenic action

    Energy Technology Data Exchange (ETDEWEB)

    Duran, A.; Perez-Rodriguez, J. L.; Herrera, L. K.; Jimenez-de-Haro, M. C.; Robador, M. D.; Justo, A.; Blanes, J. M.; Perez-Ferrer, J. C.

    2008-07-01

    Results are presented from several samples taken from leaves of the Pardon Portico of Mosque-Cathedral or Cordoba, where an alteration on their surface was detected. Metal samples analyzed using X-ray microanalysis and powder x-ray diffraction were predominantly constituted by copper with some amounts of zinc attributed to brass, whereas other samples were also constituted by copper, tin and lead attributed to bronze. surface samples were analyzed using the same techniques. In addition Fourier transform infrared spectroscopy was also used. The main compound identified in all the surface of the leaves is copper chloride hydroxide (atacamite). Lead chlorides have also been found. These data show that the sudden alteration that appears may be attributed to the use of some cleaning product containing chloride. Other compounds detected in the surface were gypsum, quartz and oxalates coming from environmental contamination. (Author) 17 refs.

  10. Exciton matter sustained by colossal dispersive interactions due to enhanced polarizability: Possible clue to ball lightning

    CERN Document Server

    Georgiev, M; Georgiev, Mladen; Singh, Jai

    2005-01-01

    Recently Gilman has pointed out that the material state of a ball lightning is both highly cohesive and flexible. He makes a specific proposal for a cohesive state arising from (colossal) Van-der-Waals attraction between highly polarizable Rydberg atoms produced under a linear lightning. We accept his general suggestions but propose that the colossal Van-der-Waals coupling may also arise from the enhanced polarizability of surrogate molecular clusters, due to the polaron gap narrowing effect. We consider a few illuminating cases and present calculations for the ammonia molecule. Although being unable to identify the exact nature of the surrogate molecules at least for the time-being, we suggest a general scenario of photoexcited vibronic excitons forming a supersaturated surrogate gas phase in which a ball arises as a result of condensation. The orange color of the luminous ball is due to radiative exciton deexcitation and suggests that there may be a unique surrogate material for ball lightning.

  11. Enhancement of Transistor-to-Transistor Variability Due to Total Dose Effects in 65-nm MOSFETs

    CERN Document Server

    Gerardin, S; Cornale, D; Ding, L; Mattiazzo, S; Paccagnella, A; Faccio, F; Michelis, S

    2015-01-01

    We studied device-to-device variations as a function of total dose in MOSFETs, using specially designed test structures and procedures aimed at maximizing matching between transistors. Degradation in nMOSFETs is less severe than in pMOSFETs and does not show any clear increase in sample-to-sample variability due to the exposure. At doses smaller than 1 Mrad( SiO2) variability in pMOSFETs is also practically unaffected, whereas at very high doses-in excess of tens of Mrad( SiO2)-variability in the on-current is enhanced in a way not correlated to pre-rad variability. The phenomenon is likely due to the impact of random dopant fluctuations on total ionizing dose effects.

  12. Critical analysis of local field enhancement due to presence of multiple dielectric materials

    International Nuclear Information System (INIS)

    This paper is aimed at critical analysis of field stress at some high voltage point in presence of multiple dielectric media. Today's high voltage systems invariably use different types of insulators i.e solid, liquid, gaseous. The appropriate insulation material is selected based on the requirement of relative permittivity and break down strength of the material. Besides the surface break down strength of two material interfaces plays important role in the high voltage design considerations of the system. In this paper, this particular phenomenon of local field enhancement due to presence of different solid and liquid dielectrics is analyzed critically. Mathematical derivations of the percentage increment of field, at the critical point, due to presence of different dielectric materials, are calculated for planar, spherical and cylindrical geometry of the high voltage elements. (author)

  13. Modeling permeability enhancement due to coupled Thermal-Hydrological-Mechanical processes in Geothermal Reservoirs

    Science.gov (United States)

    Rapaka, S.; Kelkar, S.; Zyvoloski, G.; Pawar, R. J.

    2010-12-01

    The connectivity and accessible surface area of flowing fractures, whether natural or man-made, is possibly the single most important factor, after temperature, which determines the feasibility of a geothermal reservoir. Rock deformation and in-situ stress changes induced by injected fluids can enhance the permeability and accessible surface area of the geothermal formation, while simultaneously increasing the likelihood of premature thermal breakthrough. Hence, the ability to accurately model the fracture-stress interaction in the presence of variations in temperature and fluid pressure is critical in effective reservoir development and management strategies. We will describe a general purpose computational code, FEHM, developed for this purpose, that models coupled thermal-hydrological-mechanical processes during multi-phase fluid flow and transport in fractured porous media. The code incorporates several models of fracture aperture and stress behavior combined with permeability relationships. We provide field scale examples of applications to geothermal systems to demonstrate the utility of the method. The first example studies the role played by thermal and pore-pressure effects in enhancing the permeability in the near-wellbore region. In the second example, we will study permeability enhancement due to shear stresses farther away from the wellbore.

  14. Heat Transfer Enhancement Due to Marangoni Flow Around Moving Bubbles During Nucleate Boiling

    Institute of Scientific and Technical Information of China (English)

    David M. Christopher; WANG Hao; PENG Xiaofeng

    2006-01-01

    Nucleate boiling is a very efficient method for generating high heat transfer rates from solid surfaces; however, the fundamental physical mechanisms governing nucleate boiling heat transfer are not well understood. The heat transfer mechanisms around stationary and moving bubbles on very thin microwires were analyzed numerically to evaluate the effect of the bubble motion on the heat transfer from the wire surface. The numerical analysis accurately models the experimentally observed bubble movement and fluid velocities. The analytical model includes the effects of the Marangoni flow around the bubble and the evaporation and condensation within the bubble. The analysis shows that the heat transfer was significantly enhanced by the Marangoni flow around the outside of the bubble which transfers at least twice as much energy from the wire as the heat transfer directly from the wire to the bubble. The enhanced heat transfer due to the Marangoni flow was evident for both stationary and moving bubbles. The moving bubbles also created a wake that further enhanced the heat transfer from the wire. Since the Marangoni number for water is greater than for ethanol for the same conditions, the Marangoni flow and, hence, the bubble velocities are predicted to be greater in water than in ethanol.

  15. Forest Thinning Dramatically Enhances Ozone Flux due to Reactions With Elevated Emissions of Biogenic Hydrocarbons

    Science.gov (United States)

    Goldstein, A. H.; McKay, M.; Kurpius, M. R.; Schade, G. W.

    2003-12-01

    Forests are routinely managed for timber production and fire suppression by thinning and harvesting. The impact of these activities on biosphere-atmosphere exchange of reactive trace gases is profound, but has rarely been studied in the field. Here we present simultaneous observations of ozone and terpene fluxes before, during, and after pre-commercial thinning of a ponderosa pine plantation at Blodgett Forest (1300 m elevation on the western slope of the Sierra Nevada Mountains, CA). We previously reported that monoterpene emissions increased by an order of magnitude during and following forest thinning (Schade and Goldstein, GRL 2003). We also previously reported that half the daytime ozone flux to this ecosystem under normal summertime conditions (no disturbance) was due to gas-phase chemical loss, and we suggested that this ozone loss was occurring by reactions with biogenically emitted terpenes whose lifetime was short enough that they reacted before escaping the forest canopy (Kurpius and Goldstein, GRL 2003). Here we report that ozone loss was also dramatically enhanced during and following thinning, and we link these observations to confirm that the chemical ozone loss in the canopy was indeed due to reaction with biogenically emitted compounds whose emission was enhanced by disturbance. Based on the magnitudes of ozone flux due to chemical loss and the measured terpene fluxes, we infer that the emissions of previously undetected short-lived terpenes are approximately 15-20 times those of a-pinene during thinning, and 30-50 times those of a-pinene during summer and fall. Since a-pinene accounts for approximately 25% of the total monoterpenes we routinely measure with our automated in-situ GC instrumentation, we conclude that emissions of highly reactive terpenoid compounds could have been drastically under measured in previous field campaigns and that emissions of unidentified reactive terpenes could be 5-10 times larger than emissions of total terpenes

  16. Enhancement of light absorption in polyazomethines due to plasmon excitation on randomly distributed metal nanoparticles

    Science.gov (United States)

    Wróbel, P.; Antosiewicz, T. J.; Stefaniuk, T.; Ciesielski, A.; Iwan, A.; Wronkowska, A. A.; Wronkowski, A.; Szoplik, T.

    2015-05-01

    In photovoltaic devices, metal nanoparticles embedded in a semiconductor layer allow the enhancement of solar-toelectric energy conversion efficiency due to enhanced light absorption via a prolonged optical path, enhanced electric fields near the metallic inclusions, direct injection of hot electrons, or local heating. Here we pursue the first two avenues. In the first, light scattered at an angle beyond the critical angle for reflection is coupled into the semiconductor layer and confined within such planar waveguide up to possible exciton generation. In the second, light is trapped by the excitation of localized surface plasmons on metal nanoparticles leading to enhanced near-field plasmon-exciton coupling at the peak of the plasmon resonance. We report on results of a numerical experiment on light absorption in polymer- (fullerene derivative) blends, using the 3D FDTD method, where exact optical parameters of the materials involved are taken from our recent measurements. In simulations we investigate light absorption in randomly distributed metal nanoparticles dispersed in polyazomethine-(fullerene derivative) blends, which serve as active layers in bulkheterojunction polymer solar cells. In the study Ag and Al nanoparticles of different diameters and fill factors are diffused in two air-stable aromatic polyazomethines with different chemical structures (abbreviated S9POF and S15POF) mixed with phenyl-C61-butyric acid methyl ester (PCBM) or [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM). The mixtures are spin coated on a 100 nm thick Al layer deposited on a fused silica substrate. Optical constants of the active layers are taken from spectroscopic ellipsometry and reflectance measurements using a rotating analyzer type ellipsometer with auto-retarder performed in the wavelength range from 225 nm to 2200 nm. The permittivities of Ag and Al particles of diameters from 20 to 60 nm are assumed to be equal to those measured on 100 to 200 nm thick metal films.

  17. Enhancement of quantum speed limit time due to cooperative effects in multilevel systems

    International Nuclear Information System (INIS)

    Deriving minimum evolution times is of paramount importance in quantum mechanics. Bounds on the speed of evolution are given by the so called quantum speed limit (QSL). In this work we use quantum optimal control methods to study the QSL for driven many level systems which exhibit local two-level interactions in the form of avoided crossings (ACs). Remarkably, we find that optimal evolution times are proportionally smaller than those predicted by the well-known two-level case, even when the ACs are isolated. We show that the physical mechanism for such enhancement is due to non-trivial cooperative effects between the AC and other levels, which are dynamically induced by the shape of the optimized control field. (fast track communication)

  18. Enhancement of microbial motility due to speed-dependent nutrient absorption

    CERN Document Server

    Di Salvo, Mario E

    2013-01-01

    Marine microorganisms often reach high swimming speeds, either to take advantage of evanescent nutrient patches or to beat Brownian forces. Since this implies that a sizable part of their energetic budget must be allocated to motion, it is reasonable to assume that some fast-swimming microorganisms may increase their nutrient intake by increasing their speed v. We formulate a model to investigate this hypothesis and its consequences, finding the steady state solutions and analyzing their stability. Surprisingly, we find that even modest increases in nutrient absorption may lead to a significant increase of the microbial speed. In fact, evaluations obtained using realistic parameter values for bacteria indicate that the speed increase due to the enhanced nutrient absorption may be quite large.

  19. Enhancement of microbial motility due to speed-dependent nutrient absorption

    International Nuclear Information System (INIS)

    Marine microorganisms often reach high swimming speeds, either to take advantage of evanescent nutrient patches or to beat Brownian forces. Since this implies that a sizable part of their energetic budget must be allocated to motion, it is reasonable to assume that some fast-swimming microorganisms may increase their nutrient intake by increasing their speed v. We formulate a model to investigate this hypothesis and its consequences, finding the steady-state solutions and analyzing their stability. Surprisingly, we find that even modest increases in nutrient absorption may lead to a significant increase of the microbial speed. In fact, evaluations obtained using realistic parameter values for bacteria indicate that the speed increase due to the enhanced nutrient absorption may be quite large. (paper)

  20. Large resonance enhanced second order susceptibilities in alkali halide crystals due to FA color centers

    International Nuclear Information System (INIS)

    Model calculation of second order susceptibilities for FA color centers in wide band gap materials is reported. The second order optical nonlinearity in KCL:Li crystals due to FA color centers evaluated theoretically. The density matrix formalism is employed and the equation of motion is solved by second order perturbation to evaluate the nonlinear optical susceptibility for second harmonic generation as well as frequency mixing. It is found that the system shows large resonance-enhanced second order susceptibilities (≅10-16 mV-1) for color center concentration of ≅1023 m-3. A scheme of phase matching in terms of anomalous dispersion of the centers and coherent length are discussed (Author)

  1. Strongly enhanced atomic parity violation due to close levels of opposite parity

    CERN Document Server

    Roberts, B M; Flambaum, V V

    2014-01-01

    We present calculations of nuclear-spin-dependent and nuclear-spin-independent parity violating amplitudes in Ba, Ra, Ac+, Th and Pa. Parity nonconservation in these systems is greatly enhanced due to the presence of very close electronic energy levels of opposite parity, large nuclear charge, and strong nuclear enhancement of parity-violating effects. The presented amplitudes constitute several of the largest atomic parity-violating signals predicted so far. Experiments using these systems may be performed to determine values for the nuclear anapole moment, a P-odd T-even nuclear moment given rise to by parity-violating nuclear forces. Such measurements may prove to be valuable tools in the study of parity violation in the hadron sector. The considered spin-independent transitions could also be used to measure the ratio of weak charges for different isotopes of the same atom, the results of which would serve as a test of the standard model and also of neutron distributions. Barium, with seven stable isotopes...

  2. Phosphor-doping enhanced efficiency in bilayer organic solar cells due to longer exciton diffusion length

    International Nuclear Information System (INIS)

    We fabricated bilayer organic solar cells (OSCs) in the structure glass/ITO/PEDOT:PSS/PtOEP:MEH-PPV/C70/Al, where MEH-PPV was doped with platinum octaethylporphyrin (PtOEP). Enhanced exciton diffusion length (LD) is realized via converting generated singlet excitons to triplet excitons. Investigation based on transfer matrix simulations reveals that it is the extended exciton LD of the doping donor layer that leads to the short-circuit current density (Jsc) and power conversion efficiency (PCE) improvement, when compared with those of the OSCs with a non-doping donor layer. As a result of the increased LD, Jsc and PCE increase by 30% and 42% respectively for a device with 5 wt% PtOEP-doped 25 nm-thick donor layer. Meanwhile, by doping with phosphorescent bis(1-phenyl-isoquinoline)(acetylacetonato)iridium(III), the reduction in open-circuit voltage and the comparable Jsc are shown due to its higher HOMO level and higher LUMO level, leading to the decrease of PCE. It demonstrates that doping a polymer with a suitable phosphorescent molecule is an important approach to be considered to increase the exciton LD. - Highlights: • Optical model based on transfer matrix method was used to study phosphor-doped organic planar hetero-junction solar cells. • The enhanced exciton diffusion length was experimentally investigated by absorption, PL, time-resolved transient PL, J–V and EQE curves. • Only suitable phosphor dyes can increase exciton diffusion length

  3. Phosphor-doping enhanced efficiency in bilayer organic solar cells due to longer exciton diffusion length

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Kang [Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou 510632 (China); Hou, Lintao, E-mail: thlt@jnu.edu.cn [Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou 510632 (China); Wang, Ping, E-mail: wangping996633@163.com [Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou 510632 (China); Xia, Yuxin [Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou 510632 (China); Chen, Dongcheng; Xiao, Biao [Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (China)

    2014-07-01

    We fabricated bilayer organic solar cells (OSCs) in the structure glass/ITO/PEDOT:PSS/PtOEP:MEH-PPV/C{sub 70}/Al, where MEH-PPV was doped with platinum octaethylporphyrin (PtOEP). Enhanced exciton diffusion length (L{sub D}) is realized via converting generated singlet excitons to triplet excitons. Investigation based on transfer matrix simulations reveals that it is the extended exciton L{sub D} of the doping donor layer that leads to the short-circuit current density (J{sub sc}) and power conversion efficiency (PCE) improvement, when compared with those of the OSCs with a non-doping donor layer. As a result of the increased L{sub D}, J{sub sc} and PCE increase by 30% and 42% respectively for a device with 5 wt% PtOEP-doped 25 nm-thick donor layer. Meanwhile, by doping with phosphorescent bis(1-phenyl-isoquinoline)(acetylacetonato)iridium(III), the reduction in open-circuit voltage and the comparable J{sub sc} are shown due to its higher HOMO level and higher LUMO level, leading to the decrease of PCE. It demonstrates that doping a polymer with a suitable phosphorescent molecule is an important approach to be considered to increase the exciton L{sub D}. - Highlights: • Optical model based on transfer matrix method was used to study phosphor-doped organic planar hetero-junction solar cells. • The enhanced exciton diffusion length was experimentally investigated by absorption, PL, time-resolved transient PL, J–V and EQE curves. • Only suitable phosphor dyes can increase exciton diffusion length.

  4. Simulated enhancement of ENSO-related rainfall variability due to Australian dust

    Directory of Open Access Journals (Sweden)

    L. D. Rotstayn

    2011-01-01

    Full Text Available Average dust emissions from Australia are small compared to those from the major sources in the Northern Hemisphere. However, they are highly episodic, and this may increase the importance of Australian dust as a climate feedback agent. We compare two 160-year coupled atmosphere-ocean simulations of modern-day climate using the CSIRO Mark 3.6 global climate model (GCM. The first run (DUST includes an interactive treatment of mineral dust and its direct radiative effects. The second run (NODUST is otherwise identical, but has the Australian dust source set to zero. We focus on the austral spring season, when the correlation between rainfall and the El Niño Southern Oscillation (ENSO is strongest over Australia. We find that the ENSO-rainfall relationship over eastern Australia is stronger in the DUST run: dry (El Niño years tend to be drier, and wet (La Niña years wetter. The ENSO-rainfall relationship is also weaker over north-western Australia in the DUST run. The amplification of ENSO-related rainfall variability over eastern Australia and the weaker ENSO-rainfall relationship over the north-west both represent an improvement relative to observations. The suggested mechanism over eastern Australia involves stabilisation of the surface layer due to enhanced atmospheric heating and surface cooling in El Niño years, and enhanced ascent and moisture convergence driven by atmospheric heating in La Niña years. The results suggest that (1 a realistic treatment of Australian dust may be necessary for accurate simulation of the ENSO-rainfall relationship over Australia, and (2 radiative feedbacks involving dust may be important for understanding natural rainfall variability over Australia.

  5. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules

    International Nuclear Information System (INIS)

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R1 of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ≥ 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R1 vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S–I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole 14N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of 27Al (S = 5/2) nuclei is also explained

  6. Simple expressions of the nuclear relaxation rate enhancement due to quadrupole nuclei in slowly tumbling molecules

    Energy Technology Data Exchange (ETDEWEB)

    Fries, Pascal H., E-mail: pascal-h.fries@cea.fr [Université Grenoble Alpes, INAC-SCIB, RICC, F-38000 Grenoble (France); CEA, INAC-SCIB, RICC, F-38000 Grenoble (France); Belorizky, Elie [Université Grenoble Alpes, LIPHY, F-38000 Grenoble (France); CEA, Leti-Clinatec, F-38000 Grenoble (France)

    2015-07-28

    For slowly tumbling entities or quasi-rigid lattices, we derive very simple analytical expressions of the quadrupole relaxation enhancement (QRE) of the longitudinal relaxation rate R{sub 1} of nuclear spins I due to their intramolecular magnetic dipolar coupling with quadrupole nuclei of arbitrary spins S ≥ 1. These expressions are obtained by using the adiabatic approximation for evaluating the time evolution operator of the quantum states of the quadrupole nuclei S. They are valid when the gyromagnetic ratio of the spin S is much smaller than that of the spin I. The theory predicts quadrupole resonant peaks in the dispersion curve of R{sub 1} vs magnetic field. The number, positions, relative intensities, Lorentzian shapes, and widths of these peaks are explained in terms of the following properties: the magnitude of the quadrupole Hamiltonian and the asymmetry parameter of the electric field gradient (EFG) acting on the spin S, the S-I inter-spin orientation with respect to the EFG principal axes, the rotational correlation time of the entity carrying the S–I pair, and/or the proper relaxation time of the spin S. The theory is first applied to protein amide protons undergoing dipolar coupling with fast-relaxing quadrupole {sup 14}N nuclei and mediating the QRE to the observed bulk water protons. The theoretical QRE agrees well with its experimental counterpart for various systems such as bovine pancreatic trypsin inhibitor and cartilages. The anomalous behaviour of the relaxation rate of protons in synthetic aluminium silicate imogolite nano-tubes due to the QRE of {sup 27}Al (S = 5/2) nuclei is also explained.

  7. Saturation of a toroidal Alfvén eigenmode due to enhanced damping of nonlinear sidebands

    Science.gov (United States)

    Todo, Y.; Berk, H. L.; Breizman, B. N.

    2012-09-01

    This paper examines nonlinear magneto-hydrodynamic effects on the energetic particle driven toroidal Alfvén eigenmode (TAE) for lower dissipation coefficients and with higher numerical resolution than in the previous simulations (Todo et al 2010 Nucl. Fusion 50 084016). The investigation is focused on a TAE mode with toroidal mode number n = 4. It is demonstrated that the mechanism of mode saturation involves generation of zonal (n = 0) and higher-n (n ⩾ 8) sidebands, and that the sidebands effectively increase the mode damping rate via continuum damping. The n = 0 sideband includes the zonal flow peaks at the TAE gap locations. It is also found that the n = 0 poloidal flow represents a balance between the nonlinear driving force from the n = 4 components and the equilibrium plasma response to the n = 0 fluctuations. The spatial profile of the n = 8 sideband peaks at the n = 8 Alfvén continuum, indicating enhanced dissipation due to continuum damping.

  8. Enhanced radioactivity due to natural oil and gas production and related radiological problems

    International Nuclear Information System (INIS)

    Within the scope of a research contract, the following aspects are considered: External radiation exposure at production sites; internal radiation exposures during cleaning operations such as removing of scale by sand blasting; problems of waste disposal; internal radiation exposure due to radon inhalation by consumers; the origin of the high radium content of brines from oil and gas fields. Enhanced dose rates up to 50 μSv/h have been found at the external surface of saltwater tanks, but 72% of the 160 sites investigated did not show any increase above the natural background. Brines from gas contained radium-226 up to 286 Bq/1 and scale up to 1 kBq/g. In brines and scale from oil fields radium-228 was usually the dominating radionuclide. Some samples contained significant amounts of lead-210 and even actinium-227, too, but practically no uranium or thorium. The radon-222 concentrations in natural gas samples varied between 0.004 and 4 Bq/l with an average value of 0.6 Bq/l. Related radiological problems are discussed. (orig./HP)

  9. Enhancement of Fire Safety of an Existing Green Building due to Natural Ventilation

    Directory of Open Access Journals (Sweden)

    Hong Sheng Huang

    2016-03-01

    Full Text Available In recent years, natural ventilation technology is extensively used in order to improve indoor environment quality and reduce power consumption of air-conditioning systems in green buildings. However, the effect of natural ventilation on fires needs to be evaluated carefully, and how to make these energy-saving buildings safe is a topic worth studying. This study uses Fire Dynamics Simulator on some fire safety enhancement measures for an existing green building without installation of a smoke exhaust system. Since the building is located on a school campus, it does not require a smoke exhaust system according to Taiwan fire regulations. Referential results, obtained after a series of improvement strategies are tested, show that kiln natural ventilation can generate a comfortable air flow. Unfortunately, due to the stack effect, hot air and fatal smoke are blown into the evacuation route area behind the room when a fire occurs. The findings showed that there are two feasible improvement measures, “controlling the off state of each air inlet” and “setting up an exhaust port in the rear of room”, which can effectively resolve the fire safety issues; the construction of which can be undertaken at a reasonable cost.

  10. The evolution of future geogenic matter fluxes due Enhanced Weathering: Results from the Antwerp Experiment

    Science.gov (United States)

    Hartmann, Jens; Weiss, Andreas; Struyf, Eric; Schoelynck, Jonas; Meire, Patrick; Amann, Thorben

    2015-04-01

    Understanding the evolution of geogenic matter fluxes in soils due the application of rock products ontop of soils is relevant to evaluate alteration of soil solutions and saturation states of solutes. In the future the practice of applying rock products will continue and areas affected will likely spread (Hartmann et al., 2013). This trend will likely be fuelled by attempts to optimize carbon dioxide removal by increasing biomass production, soil organic carbon stocks, increase crop production or afforestation. All those efforts demand a certain amount of geogenic nutrients, which need to be replaced. To investigate the release patterns and the downward transport of an array of elements, and to study their fate as well as reaction processes, altered through this practice, a mesocosm experiment was established at Antwerp University. Extended results will be presented (c.f., Weiss et al., 2014) focusing on the release and transport of DIC (dissolved inorganic carbon) and Mg (magnesium) in the soil column downwards after the application of 22 kg m-2 olivine powder. Elevated DIC and Mg concentrations are detected in case of olivine is applied to mesocosms with wheat and barley, if compared to the mesocsoms without plants, and without olivine. The change patterns in concentrations and fluxes will be discussed. Hartmann, J., et al. (2013) Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification. Reviews of Geophysics; 51(2), 113-149. doi: 10.1002/rog.20004 Weiss, A., et al. (2014) The overlooked compartment of the critical-zone-complex, considering the evolution of future geogenic matter fluxes: Agricultural topsoils. Procedia Earth and Planetary Science, 10, 339-342. doi:10.1016/j.proeps.2014.08.032

  11. Interactions of anthropogenic stress factors on phytoplankton

    Directory of Open Access Journals (Sweden)

    Donat P. Häder

    2015-03-01

    Full Text Available Phytoplankton are the main primary producers in aquatic ecosystems. Their biomass production and CO2 sequestration equals that of all terrestrial plants taken together. Phytoplankton productivity is controlled by a number of environmental factors, many of which currently undergo substantial changes due to anthropogenic global climate change. Light availability is an absolute requirement for photosynthesis, but excessive visible and UV radiation impair productivity. Increasing temperatures enhance stratification, decrease the depth of the upper mixing layer exposing the cells to higher solar radiation, and reduce nutrient upward transport from deeper layers. At the same time, stratospheric ozone depletion exposes phytoplankton to higher solar UV-B radiation especially in polar and mid latitudes. Terrestrial runoff carrying sediments and dissolved organic matter into coastal waters leads to eutrophication while reducing UV penetration. All these environmental forcings are known to affect physiological and ecological processes of primary producers. Ocean acidification due to increased atmospheric CO2 concentrations changes the seawater chemistry; it reduces calcification in phytoplankton, macroalgae and many zoological taxa and enhances UV-induced damage. Ocean warming results in changing species composition and favors blooms of toxic prokaryotic and eukaryotic phytoplankton; it moderates UV-induced damage of the photosynthetic apparatus because of higher repair rates. Increasing pollution from crude oil spills, persistent organic pollutants, heavy metal as well as industrial and household wastewaters affect phytoplankton, which is augmented by solar UV radiation. In view of the fact that extensive analyses of the impacts of multiple stressors are scarce, here we review reported findings on the impacts of anthropogenic stressors on phytoplankton with an emphasis on their interactive effects and a prospect for future studies.

  12. Climatic impacts of anthropogenic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Iversen, T. [Oslo Univ. (Norway)

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Anthropogenic production of aerosols is mainly connected with combustion of fossil fuel. Measured by particulate mass, the anthropogenic sulphate production is the dominating source of aerosols in the Northern Hemisphere. Particles emitted in mechanical processes, fly ash etc. are less important because of their shorter atmospheric residence time. Possible climatological effects of anthropogenic aerosols are usually classified in two groups: direct and indirect. Direct effects are alterations of the radiative heating budget due to the aerosol particles in clear air. Indirect effects involve the interaction between particles and cloud processes. A simplified one-layer radiation model gave cooling in the most polluted mid-latitude areas and heating due to soot absorption in the Arctic. This differential trend in heating rates may have significant effects on atmospheric meridional circulations, which is important for the atmosphere as a thermodynamic system. Recently the description of sulphur chemistry in the hemispheric scale dispersion model has been improved and will be used in a model for Mie scattering and absorption

  13. Nuclear quadrupole resonance (NQR) enhancement by polarization transfer and its limitation due to relaxation

    International Nuclear Information System (INIS)

    Aiming for polarization transfer enhancement of 14N nuclear quadrupole resonance (NQR) for the detection of explosives with low NQR frequencies, we examine the potential and limitations of this method. As illustrative sample materials two non-explosive compounds, urotropine (C6H12N4) and urea (CON2H4) with NQR frequencies of 3.3 MHz and 2.8 MHz, respectively, have been chosen. In both substances the NQR signal can be easily seen. In urotropine no signal enhancement has been detected. The reason is a 14N spin-lattice relaxation time being much shorter than the 1H-14N polarization transfer time. Although in urea the signal enhancement is significant there is, because of the long 1H polarization time, still no effective gain as compared with the pure NQR signal accumulated during the same time interval. To estimate the expected NQR signal enhancement, a polarization enhancement factor has been derived in terms of a simplified theoretical treatment, neglecting spin-lattice relaxation. The substantial influence of relaxation effects on the signal enhancement has been discussed in a qualitative manner in connection with the experiments performed for urea and urotropine

  14. Nuclear quadrupole resonance (NQR) enhancement by polarization transfer and its limitation due to relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Privalov, A F [Inst. f. Festkoerperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt (Germany); Kruk, D [Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland); Gaedke, A [Inst. f. Festkoerperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt (Germany); Stork, H [Inst. f. Festkoerperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt (Germany); Fujara, F [Inst. f. Festkoerperphysik, TU Darmstadt, Hochschulstr. 6, 64289 Darmstadt (Germany)

    2007-12-07

    Aiming for polarization transfer enhancement of {sup 14}N nuclear quadrupole resonance (NQR) for the detection of explosives with low NQR frequencies, we examine the potential and limitations of this method. As illustrative sample materials two non-explosive compounds, urotropine (C{sub 6}H{sub 12}N{sub 4}) and urea (CON{sub 2}H{sub 4}) with NQR frequencies of 3.3 MHz and 2.8 MHz, respectively, have been chosen. In both substances the NQR signal can be easily seen. In urotropine no signal enhancement has been detected. The reason is a {sup 14}N spin-lattice relaxation time being much shorter than the {sup 1}H-{sup 14}N polarization transfer time. Although in urea the signal enhancement is significant there is, because of the long {sup 1}H polarization time, still no effective gain as compared with the pure NQR signal accumulated during the same time interval. To estimate the expected NQR signal enhancement, a polarization enhancement factor has been derived in terms of a simplified theoretical treatment, neglecting spin-lattice relaxation. The substantial influence of relaxation effects on the signal enhancement has been discussed in a qualitative manner in connection with the experiments performed for urea and urotropine.

  15. Modeling shear failure and permeability enhancement due to coupled Thermal-Hydrological-Mechanical processes in Enhanced Geothermal Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, Sharad [Los Alamos National Laboratory

    2011-01-01

    The connectivity and accessible surface area of flowing fractures, whether natural or man-made, is possibly the single most important factor, after temperature, which determines the feasibility of an Enhanced Geothermal System (EGS). Rock deformation and in-situ stress changes induced by injected fluids can lead to shear failure on preexisting fractures which can generate microseismic events, and also enhance the permeability and accessible surface area of the geothermal formation. Hence, the ability to accurately model the coupled thermal-hydrologic-mechanical (THM) processes in fractured geological formations is critical in effective EGS reservoir development and management strategies. The locations of the microseismic events can serve as indicators of the zones of enhanced permeability, thus providing vital information for verification of the coupled THM models. We will describe a general purpose computational code, FEHM, developed for this purpose, that models coupled THM processes during multiphase fluid flow and transport in fractured porous media. The code incorporates several models of fracture aperture and stress behavior combined with permeability relationships. We provide field scale examples of applications to geothermal systems to demonstrate the utility of the method.

  16. Imaging enhancement of a photonic crystal superlens due to a surface mode with a specific dispersion

    Science.gov (United States)

    Shen, Yifeng; Wu, Fangfang; Wang, Yongchun; Li, Lulu; Guo, Changqing

    2012-10-01

    We study the imaging process for a photonic crystal slab lens with a surface defect by the finite-difference-time-domain (FDTD) method. We demonstrate an odd surface mode with a specific dispersion curve in this system. The dispersion curve has an extreme point, which is corresponding to a slow light. If the working frequency is chosen at this extreme point the subwavelength resolution of image will be enhanced. Moreover, the subwavelength resolution of image is very sensitive to the position of this extreme point in the dispersion diagram. Longer interaction time and better field distribution may give a qualitative physical understanding for the enhancement of imaging quality.

  17. Modified field enhancement and extinction by plasmonic nanowire dimers due to nonlocal response

    DEFF Research Database (Denmark)

    Toscano, Giuseppe; Raza, Søren; Jauho, Antti-Pekka;

    2012-01-01

    in a wide frequency range against analytical results for the extinction cross section of a cylindrical plasmonic nanowire. Our main results concern more complex geometries, namely cylindrical and bow-tie nanowire dimers that can strongly enhance optical fields. For both types of dimers we find that...

  18. Is the inhibition/enhancement of fusion due to breakup still a puzzle?

    International Nuclear Information System (INIS)

    The effect of breakup in the fusion cross section in terms of suppression versus enhancement, discussed in a conflicting way in the literature, is addressed. Data and theoretical predictions available in the literature are compared. Excitation functions of the sub- and near-barrier fusion cross-sections for a wide variety of light and heavy systems are presented and interpreted. We have measured fusion excitation functions and breakup correlation functions for the medium weight systems 6 Li + 59 Co and 7 Li + 59 Co. These measurements help to establish the influence of the projectile breakup on the fusion process at near-barrier energies and contribute to the determination of how the mass of the target affects the breakup role. The results indicate a light fusion enhancement at sub-barrier energies and a geometry dominated cross section at barrier energies. (author)

  19. Enhanced disinfection by-product formation due to nanoparticles in wastewater treatment plant effluents

    OpenAIRE

    Metch, Jacob W.; Ma, Yanjun; Pruden, Amy; Vikesland, Peter J.

    2015-01-01

    Nanoparticles (NPs) are increasingly being incorporated into consumer products and are being used for industrial applications in ways that will lead to their environmental dissemination via wastewater treatment plants (WWTPs). Many NPs possess catalytic properties that could potentially enhance undesired chemical reactions such as the formation of disinfection by-products during disinfection of wastewater effluent. In this effort, silver (AgNPs), titanium dioxide (TiO2), ceria (CeO2), and nan...

  20. Enhancements of the Andreev conductance due to emission/absorption of bosonic quanta

    International Nuclear Information System (INIS)

    We predict that the subgap spectrum and transport properties of the quantum dot embedded between superconducting and metallic reservoirs can be substantially enhanced by emission/absorption of external bosonic quanta. Upon tuning the gate voltage the in-gap Andreev states eventually interfere with each other. We explore the measurable signatures of such interference appearing in the differential conductance for both linear and nonlinear regimes. (paper)

  1. Molecular hot electroluminescence due to strongly enhanced spontaneous emission rates in a plasmonic nanocavity.

    Science.gov (United States)

    Chen, Gong; Li, Xiao-Guang; Zhang, Zhen-Yu; Dong, Zhen-Chao

    2015-02-14

    We have recently demonstrated anomalous relaxationless hot electroluminescence from molecules in the tunnel junction of a scanning tunneling microscope [Dong et al., Nat. Photonics, 2010, 4, 50]. In the present paper, based on physically realistic parameters, we aim to unravel the underlying physical mechanism using a multiscale modeling approach that combines classical generalized Mie theory with the quantum master equation. We find that the nanocavity-plasmon-tuned spontaneous emission rate plays a crucial role in shaping the spectral profile. In particular, on resonance, the radiative decay rate can be enhanced by three-to-five orders of magnitude, which enables the radiative process to occur on the lifetime scale of picoseconds and become competitive to the vibrational relaxation. Such a large Purcell effect opens up new emission channels to generate the hot luminescence that arises directly from higher vibronic levels of the molecular excited state. We also stress that the critical role of resonant plasmonic nanocavities in tunneling electron induced molecular luminescence is to enhance the spontaneous radiative decay through plasmon enhanced vacuum fluctuations rather than to generate an efficient plasmon stimulated emission process. This improved understanding has been partly overlooked in previous studies but is believed to be very important for further developments of molecular plasmonics and optoelectronics. PMID:25565003

  2. Drag enhancement due to macro-chains in uniformly magnetized ferrofluids

    Energy Technology Data Exchange (ETDEWEB)

    Yecko, Philip, E-mail: philip.yecko@montclair.ed [Department of Mathematical Sciences, Montclair State University, Montclair, NJ 07043 (United States); Lee, Wah-Keat [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); David Trubatch, A.; Vieira, Matthew [Department of Mathematical Sciences, Montclair State University, Montclair, NJ 07043 (United States)

    2011-05-15

    We report on experiments and simulations performed on small non-magnetic glass balls and nearly spherical gas bubbles moving through a uniformly magnetized ferrofluid. Use of the Advanced Photon Source X-ray beamline at Argonne National Laboratory permitted sufficient spatial and temporal resolution to accurately track the dynamics of these 500{mu}m diameter spheres simultaneously with an array of magnetic particle macro-chains -agglomerations each of several mm long and 4-20{mu}m thick. The enhanced drag induced by the macro-chains is substantial: we infer viscosity coefficients up to four times larger than for unmagnetized fluid. We provide direct visualization of a possible mechanism by which macro-chains mechanically impede the transverse motion of spheres, enhancing the drag and effecting an anisotropic viscosity. Direct numerical simulations of spheres falling through magnetic fluid can reproduce the observed dynamics by means of a phenomenological magnetization-dependent viscosity model with one free parameter. - Research Highlights: X-ray phase-contrast imaging was used to examine ferrofluid. Suspended nanoparticles formed long chains of {approx}10{mu}m thickness. Viscosity was enhanced for objects in motion transverse to chains. Encounters with individual chains were apparent in objects motion. Direct numerical simulation model was performed with a VOF code.

  3. Drag enhancement due to macro-chains in uniformly magnetized ferrofluids

    International Nuclear Information System (INIS)

    We report on experiments and simulations performed on small non-magnetic glass balls and nearly spherical gas bubbles moving through a uniformly magnetized ferrofluid. Use of the Advanced Photon Source X-ray beamline at Argonne National Laboratory permitted sufficient spatial and temporal resolution to accurately track the dynamics of these 500μm diameter spheres simultaneously with an array of magnetic particle macro-chains -agglomerations each of several mm long and 4-20μm thick. The enhanced drag induced by the macro-chains is substantial: we infer viscosity coefficients up to four times larger than for unmagnetized fluid. We provide direct visualization of a possible mechanism by which macro-chains mechanically impede the transverse motion of spheres, enhancing the drag and effecting an anisotropic viscosity. Direct numerical simulations of spheres falling through magnetic fluid can reproduce the observed dynamics by means of a phenomenological magnetization-dependent viscosity model with one free parameter. - Research Highlights: →X-ray phase-contrast imaging was used to examine ferrofluid. → Suspended nanoparticles formed long chains of ∼10μm thickness. →Viscosity was enhanced for objects in motion transverse to chains. →Encounters with individual chains were apparent in objects motion. →Direct numerical simulation model was performed with a VOF code.

  4. Enhanced Tunneling Electroresistance in Ferroelectric Tunnel Junctions due to the Reversible Metallization of the Barrier

    Science.gov (United States)

    Liu, Xiaohui; Burton, J. D.; Tsymbal, Evgeny Y.

    2016-05-01

    Realizing a large tunneling electroresistance (TER) effect is crucial for device application of ferroelectric tunnel junctions (FTJs). FTJs are typically composed of a thin ferroelectric layer sandwiched by two metallic electrodes, where TER generally results from the dependence of the effective tunneling barrier height on the ferroelectric polarization. Since the resistance depends exponentially not only on barrier height but also on barrier width, TER is expected to be greatly enhanced when one of the electrodes is a semiconductor where the depletion region near the interface can be controlled via ferroelectric polarization. To explore this possibility, we perform studies of SrRuO3/BaTiO3/n -SrTiO3 FTJs, where n -SrTiO3 is an electron doped SrTiO3 electrode, using first-principles density functional theory. Our studies reveal that, in addition to modulation of the depletion region in n -SrTiO3 , the BaTiO3 barrier layer becomes conducting near the interface for polarization pointing into n -SrTiO3 , leading to dramatic enhancement of TER. The effect is controlled by the band alignment between the semiconductor and the ferroelectric insulator and opens the way for experimental realization of enhanced TER in FTJs through the choice of a semiconducting electrode and interface engineering.

  5. Estimate of return periods for enhanced gamma ray dose rates due to precipitation

    International Nuclear Information System (INIS)

    In order to contribute for the establishment of criteria whether the high level of gamma (γ) ray dose rate is an unusual value, statistical analysis for its frequency distribution was carried out. The γ ray dose rates monitored at six sites (Minamihoroni, Kariwa, Wajima, Asahikawa, Ohno, and Tokai-mura Oshinobe) in Japan during the periods from 2000 to 2004 were subjected to the analysis. The γ ray dose rates were not normally distributed but the distribution distorted to higher side. Our statistical analysis suggests that the γ ray dose rates above 'average + 3σ' or '100nGy/h', which are the conventional definition, occurred frequently. Here we propose the use of more suitable method to detect the unusual value of the enhanced γ ray dose rates on the basis of the 'return period'. It is the recurrence frequency of high γ ray dose rates. Estimate of the return periods, which is usually used for the extreme event of meteorology, is given for the first time in this field. In this study, we compared two methods to calculate the return periods: empirical return period (TH) based on Hazen plot by using the enhanced γ ray dose rates and theoretical estimated return period (TG) based on Gumbel distribution by using average and standard deviation of the enhanced γ ray dose rates. There were significant difference of TH as well as TG between monitoring sites. It turned out that the judgement of an unusual value must be considered based on TH and TG at each monitoring site. (author)

  6. Rainfall consistently enhanced around the Gezira Scheme in East Africa due to irrigation

    Science.gov (United States)

    Alter, Ross E.; Im, Eun-Soon; Eltahir, Elfatih A. B.

    2015-10-01

    Land-use and land-cover changes have significantly modified regional climate patterns around the world. In particular, the rapid development of large-scale cropland irrigation over the past century has been investigated in relation to possible modification of regional rainfall. In regional climate simulations of the West African Sahel, hypothetical large-scale irrigation schemes inhibit rainfall over irrigated areas but enhance rainfall remotely. However, the simulated influence of large-scale irrigation schemes on precipitation patterns cannot be substantiated without direct comparison to observations. Here we present two complementary analyses: numerical simulations using a regional climate model over an actual, large-scale irrigation scheme in the East African Sahel--the Gezira Scheme--and observational analyses over the same area. The simulations suggest that irrigation inhibits rainfall over the Gezira Scheme and enhances rainfall to the east. Observational analyses of rainfall, temperature and streamflow in the same region support the simulated results. The findings are consistent with a mechanistic framework in which irrigation decreases surface air temperature, causing atmospheric subsidence over the irrigated area and clockwise wind anomalies (in background southwesterly winds) that increase upward vertical motion to the east. We conclude that irrigation development can consistently modify rainfall patterns in and around irrigated areas, warranting further examination of potential agricultural, hydrologic and economic implications.

  7. Enhanced O2+ loss at Mars due to an ambipolar electric field from electron heating

    Science.gov (United States)

    Ergun, R. E.; Andersson, L. A.; Fowler, C. M.; Woodson, A. K.; Weber, T. D.; Delory, G. T.; Andrews, D. J.; Eriksson, A. I.; McEnulty, T.; Morooka, M. W.; Stewart, A. I. F.; Mahaffy, P. R.; Jakosky, B. M.

    2016-05-01

    Recent results from the MAVEN Langmuir Probe and Waves instrument suggest higher than predicted electron temperatures (Te) in Mars' dayside ionosphere above ~180 km in altitude. Correspondingly, measurements from Neutral Gas and Ion Mass Spectrometer indicate significant abundances of O2+ up to ~500 km in altitude, suggesting that O2+ may be a principal ion loss mechanism of oxygen. In this article, we investigate the effects of the higher Te (which results from electron heating) and ion heating on ion outflow and loss. Numerical solutions show that plasma processes including ion heating and higher Te may greatly increase O2+ loss at Mars. In particular, enhanced Te in Mars' ionosphere just above the exobase creates a substantial ambipolar electric field with a potential (eΦ) of several kBTe, which draws ions out of the region allowing for enhanced escape. With active solar wind, electron, and ion heating, direct O2+ loss could match or exceed loss via dissociative recombination of O2+. These results suggest that direct loss of O2+ may have played a significant role in the loss of oxygen at Mars over time.

  8. Simulation study of dose enhancement in a cell due to nearby carbon and oxygen in particle radiotherapy

    CERN Document Server

    Shin, Jae Ik; Cho, Sungho; Kim, Eun Ho; Song, Yongkeun; Jung, Won-Gyun; Yoo, SeungHoon; Shin, Dongho; Lee, Se Byeong; Yoon, Myonggeun; Incerti, Sebastian; Geso, Moshi; Rosenfeld, Anatoly B

    2015-01-01

    The aim of this study is to investigate the dose-deposition enhancement by alpha-particle irradiation in a cellular model using carbon and oxygen chemical compositions.A simulation study was performed to study dose enhancement due to carbon and oxygen for a human cell where Geant4 code used for the alpha-particle irradiation to the cellular phantom. The characteristic of dose enhancement in the nucleus and cytoplasm by the alpha-particle radiation was investigated based on concentrations of the carbon and oxygen compositions and was compared with those by gold and gadolinium.The results show that both the carbon and oxygen-induced dose enhancement was found to be more effective than those of gold and gadolinium. We found that the dose-enhancement effect was more dominant in the nucleus than in the cytoplasm if carbon or oxygen is uniformly distributed in a whole cell. In the condition that the added chemical composition was inserted only into the cytoplasm, the effect of the dose enhancement in nucleus become...

  9. Enhanced Xylitol Production by Mutant Kluyveromyces marxianus 36907-FMEL1 Due to Improved Xylose Reductase Activity.

    Science.gov (United States)

    Kim, Jin-Seong; Park, Jae-Bum; Jang, Seung-Won; Ha, Suk-Jin

    2015-08-01

    A directed evolution and random mutagenesis were carried out with thermotolerant yeast Kluyveromyces marxianus ATCC 36907 for efficient xylitol production. The final selected strain, K. marxianus 36907-FMEL1, exhibited 120 and 39 % improvements of xylitol concentration and xylitol yield, respectively, as compared to the parental strain, K. marxianus ATCC 36907. According to enzymatic assays for xylose reductase (XR) activities, XR activity from K. marxianus 36907-FMEL1 was around twofold higher than that from the parental strain. Interestingly, the ratios of NADH-linked and NADPH-linked XR activities were highly changed from 1.92 to 1.30 when K. marxianus ATCC 36907 and K. marxianus 36907-FMEL1 were compared. As results of KmXYL1 genes sequencing, it was found that cysteine was substituted to tyrosine at position 36 after strain development which might cause enhanced XR activity from K. marxianus 36907-FMEL1. PMID:26043853

  10. Intensity enhancement of O VI ultraviolet emission lines in solar spectra due to opacity

    CERN Document Server

    Keenan, F P; Madjarska, M S; Rose, S J; Bowler, L A; Britton, J; McCrink, L; Mathioudakis, M

    2014-01-01

    Opacity is a property of many plasmas, and it is normally expected that if an emission line in a plasma becomes optically thick, its intensity ratio to that of another transition that remains optically thin should decrease. However, radiative transfer calculations undertaken both by ourselves and others predict that under certain conditions the intensity ratio of an optically thick to thin line can show an increase over the optically thin value, indicating an enhancement in the former. These conditions include the geometry of the emitting plasma and its orientation to the observer. A similar effect can take place between lines of differing optical depth. Previous observational studies have focused on stellar point sources, and here we investigate the spatially-resolved solar atmosphere using measurements of the I(1032 A)/I(1038 A) intensity ratio of O VI in several regions obtained with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument on board the Solar and Heliospheric Observatory (...

  11. Electric field enhancement due to a saw-tooth asperity in a channel and implications on microscale gas breakdown

    International Nuclear Information System (INIS)

    The electric field enhancement due to an isolated saw-tooth asperity in an infinite channel is considered with the goal of providing some inputs to the choice of field enhancement factors used to describe microscale gas breakdown. The Schwarz–Christoffel transformation is used to map the interior of the channel to the upper half of the transformed plane. The expression for the electric field in the transformed plane is then used to determine the electric field distribution in the channel as well as field enhancement near the asperity. The effective field enhancement factor is determined and its dependence on operating and geometrical parameters is studied. While the effective field enhancement factor depends only weakly on the height of the asperity in comparison to the channel, it is influenced significantly by the base angles of the asperity. Due to the strong dependence of field emission current density on electric field, the effective field enhancement factor (βeff) is shown to vary rapidly with the applied electric field irrespective of the geometrical parameters. This variation is included in the analysis of microscale gas breakdown and compared with results obtained using a constant βeff as is done traditionally. Even though results for a varying βeff may be approximately reproduced using an equivalent constant βeff independent of E-field, it might be important for a range of operating conditions. This is confirmed by extracting βeff from experimental data for breakdown in argon microgaps with plane-parallel cathodes and comparing its dependence on the E-field. While the use of two-dimensional asperities is shown to be a minor disadvantage of the proposed approach in its current form, it can potentially help in developing predictive capabilities as opposed to treating βeff as a curve-fitting parameter. (paper)

  12. Energy enhancement and spectrum narrowing in terahertz electron sources due to negative mass instability

    Science.gov (United States)

    Lurie, Yu.; Bratman, V. L.; Savilov, A. V.

    2016-05-01

    Simulations of coherent spontaneous undulator radiation in a waveguide demonstrate that the use of negative mass instability (NMI) for retaining longitudinal sizes of dense electron bunches, which are formed in laser-driven photoinjectors, allows one to increase power capabilities of a terahertz radiation source by many times. The NMI is realized in an undulator with combined helical and over-resonance uniform longitudinal magnetic fields due to nonisochronous longitudinal oscillations of electrons, whose frequencies increase/decrease with increasing/decreasing particle energy. In such conditions, an effective longitudinal size of the bunches can be preserved at long distance even at an extremely high electron density. Correspondingly, an energy extraction efficiency of more than 20% is revealed at a narrow frequency radiation spectrum, suggesting realization of a compact and powerful THz source.

  13. Enhanced Downward Acceleration of a Bouncing Droplet Due to the Lubrication Force

    Science.gov (United States)

    Chappell, David; Cessna, Matthew; Nadim, Ali

    2015-11-01

    We explore the dynamics of moderately viscous (50-100 cSt) silicone oil drops bouncing on a vertically vibrated oil bath. When the driving acceleration of the bath is larger than a threshold value, drops can bounce indefinitely due to the presence of a thin air layer separating the drop from the bath. We present experimental evidence that the drop can temporarily ``stick'' to the oil bath during the rebound process causing it to be pulled downward briefly with the downward-accelerating bath. Thus, for a small time interval during each bounce, the drop's downward acceleration can exceed that of gravitational free-fall. A simple model incorporating the lubrication force between the drop and the bath, allowing for the deformation of the latter, is developed and found to match the observed dynamics closely.

  14. Natural versus anthropogenic inhalable aerosol chemistry of transboundary East Asian atmospheric outflows into western Japan.

    Science.gov (United States)

    Moreno, Teresa; Kojima, Tomoko; Querol, Xavier; Alastuey, Andrés; Amato, Fulvio; Gibbons, Wes

    2012-05-01

    The eastward transport of aerosols exported from mainland Asia strongly influences air quality in the Japanese archipelago. The bulk of the inhalable particulate matter (PM(10)) in these intrusions comprises either natural, desert-derived minerals (mostly supermicron silicates) or anthropogenic pollutants (mostly submicron sulphates), in various states of mixing. We analyse PM(10) collected in Kumamoto, SW Japan, during three contrasting types of aerosol intrusions, the first being dominated by desert PM which became increasingly mixed with anthropogenic components as time progressed, the second being a relatively minor event mixing fine, distal desert PM with anthropogenic materials, and the third being dominated by anthropogenic pollutants. Whereas the chemistry of the natural mineral component is characterised by "crustal" elements (Si, Al, Fe, Mg, K, Li, P, Sc, V, Rb, Sr, Zr, Th, lanthanoids), the anthropogenic component is rich in secondary inorganic compounds and more toxic metallic elements (NH(4)(+), SO(4)(2-), As, Pb, Cd, Cu, Zn, Sn, Bi, Sb, and Ge). Some desert-dust (Kosa) intrusions are more calcareous than others, implicating geologically different source areas, and contain enhanced levels of NO(3)(-), probably as supermicron Ca(NO(3))(2) particles produced by chemical reaction between NOx pollutants (mostly from industry and traffic) and carbonate during atmospheric transport. The overall trace element chemistry of aerosol intrusions into Kumamoto shows low V/Rb, low NO(3)(-)/SO(4)(2-), enhanced As levels, and unfractionated La/Ce values, which are all consistent with anthropogenic sources including coal emissions rather than those derived from the refining and combustion of oil fractionates. Geographically dispersed, residual sulphatic plumes of this nature mix with local traffic (revealed by OC and EC concentrations) and industrial emissions and dissipate only slowly, due to the dominance of submicron accumulation mode PM which is atmospherically

  15. Enhanced optical properties due to indium incorporation in zinc oxide nanowires

    International Nuclear Information System (INIS)

    Indium-doped zinc oxide nanowires grown by vapor-liquid-solid technique with 1.6 at. % indium content show intense room temperature photoluminescence (PL) that is red shifted to 20 meV from band edge. We report on a combination of nanowires and nanobelts-like structures with enhanced optical properties after indium doping. The near band edge emission shift gives an estimate for the carrier density as high as 5.5 × 1019 cm−3 for doped nanowires according to Mott's critical density theory. Quenching of the visible green peak is seen for doped nanostructures indicating lesser oxygen vacancies and improved quality. PL and transmission electron microscopy measurements confirm indium doping into the ZnO lattice, whereas temperature dependent PL data give an estimation of the donor and acceptor binding energies that agrees well with indium doped nanowires. This provides a non-destructive technique to estimate doping for 1D structures as compared to the traditional FET approach. Furthermore, these indium doped nanowires can be a potential candidate for transparent conducting oxides applications and spintronic devices with controlled growth mechanism

  16. Preferential accumulation and enhanced relative velocity of inertial droplets due to interactions with homogeneous isotropic turbulence

    Science.gov (United States)

    Bateson, Colin; Aliseda, Alberto

    2015-11-01

    We present results from wind tunnel experiments on the evolution of small inertial (d ~ 10 - 200 μm) water droplets in homogeneous, isotropic, slowly decaying grid turbulence. High-speed imaging and a Particle Tracking algorithm are used to calculate relative velocity distributions. We analyze the preferential concentration, via the 2D Radial Distribution Function, and enhanced relative velocity of droplets resulting from their inertial interactions with the underlying turbulence. The two-dimensional particle velocities, measured from multi-image tracks along a streamwise plane, are conditionally analyzed with respect to the distance from the nearest particle. We focus on the non-normality of the statistics for the particle-particle separation velocity component to examine the influence of the inertial interaction with the turbulence on the dynamics of the droplets. We observe a negative bias (in the mean and mode) in the separation velocity of particles for short separations, signaling a tendency of particles to collide more frequently than a random agitation by turbulence would predict. The tails of the distribution are interpreted in terms of the collision/coalescence process and the probability of collisions that do not lead to coalescence.

  17. Andrographolide radiosensitizes human ovarian cancer SKOV3 xenografts due to an enhanced apoptosis and autophagy.

    Science.gov (United States)

    Zhang, Chao; Qiu, Xingsheng

    2015-11-01

    Andrographolide (AND), a diterpenoid lactone isolated from Andrographis paniculata, has been shown to have radiosensitivity in several types of cancer. Whether AND can radiosensitize ovarian cancer remains unknown. The present study investigated the radiosensitizing effects of AND in human ovarian SKOV3 xenografts and examined the molecular mechanisms of AND-mediated radiosensitization. Nude mice bearing human ovarian SKOV3 were treated with AND to investigate the effects of drug administration on tumor growth, radiosensitivity, apoptosis, and autophagy. Subsequent Western blot analysis and monodansylcadaverine (MDC) staining (autophagy analysis) were used to determine the role of AND. Finally, the pathway of apoptosis was characterized by caspase-3 activity assay as well as TUNEL analysis. AND potently sensitized SKOV3 xenografts to radiation. Moreover, apoptosis and autophagy in radiation combined with drug-treated xenografts increased significantly compared with the simple drug or single radiation treatment. This result was associated with an increase in the Bax/Bcl-2 protein ratio and p-p53 expression after exposure to combination treatment. Meanwhile, the level of Beclin 1 and Atg5 and the conversion from LC3-I to LC3-II, three important proteins involved in autophagy, were increased. AND acts as a strong radiosensitizer in human ovarian SKOV3 xenografts in vivo by increasing the Bax/Bcl-2 protein ratio and promoting the activation of caspase-3, leading to enhanced apoptosis as well as autophagy. PMID:26014516

  18. Experimental Study for Heat Transfer Enhancement Due To Surface Roughness at Laminar Flow

    Directory of Open Access Journals (Sweden)

    Raju R.Yenare

    2014-03-01

    Full Text Available An investigation was conducted to determine whether dimples on a heat sink fin can increase heat transfer for laminar airflows. This was accomplished by performing experimental studies using two different types of dimples: 1 circular (spherical dimples, and 2 oval (elliptical dimples. Dimples were placed on both sides of a aluminium plate with a relative pitch of S/D=1.21 and relative depth of δ/D=0.16 (e.g., circular dimples. For oval dimples, similar ratios with the same total depth and circular-edge-to-edge distance as the circular dimples were used. For those configurations the average heat transfer coefficient, pressure drop, thermal performance and Nusselt number ratio were determined experimentally. For circular and oval dimples, heat transfer enhancements (relative to a flat plate were observed for Reynolds number range from 600 to 2000 (Reynolds number based on channel height. Also the results are validated analytically for Nusselt number and friction factor for plain vertical plate.

  19. Enhanced spin Seebeck effect signal due to spin-momentum locked topological surface states.

    Science.gov (United States)

    Jiang, Zilong; Chang, Cui-Zu; Masir, Massoud Ramezani; Tang, Chi; Xu, Yadong; Moodera, Jagadeesh S; MacDonald, Allan H; Shi, Jing

    2016-01-01

    Spin-momentum locking in protected surface states enables efficient electrical detection of magnon decay at a magnetic-insulator/topological-insulator heterojunction. Here we demonstrate this property using the spin Seebeck effect (SSE), that is, measuring the transverse thermoelectric response to a temperature gradient across a thin film of yttrium iron garnet, an insulating ferrimagnet, and forming a heterojunction with (BixSb1-x)2Te3, a topological insulator. The non-equilibrium magnon population established at the interface can decay in part by interactions of magnons with electrons near the Fermi energy of the topological insulator. When this decay channel is made active by tuning (BixSb1-x)2Te3 into a bulk insulator, a large electromotive force emerges in the direction perpendicular to the in-plane magnetization of yttrium iron garnet. The enhanced, tunable SSE which occurs when the Fermi level lies in the bulk gap offers unique advantages over the usual SSE in metals and therefore opens up exciting possibilities in spintronics. PMID:27142594

  20. Enhanced spin Seebeck effect signal due to spin-momentum locked topological surface states

    Science.gov (United States)

    Jiang, Zilong; Chang, Cui-Zu; Masir, Massoud Ramezani; Tang, Chi; Xu, Yadong; Moodera, Jagadeesh S.; MacDonald, Allan H.; Shi, Jing

    2016-05-01

    Spin-momentum locking in protected surface states enables efficient electrical detection of magnon decay at a magnetic-insulator/topological-insulator heterojunction. Here we demonstrate this property using the spin Seebeck effect (SSE), that is, measuring the transverse thermoelectric response to a temperature gradient across a thin film of yttrium iron garnet, an insulating ferrimagnet, and forming a heterojunction with (BixSb1-x)2Te3, a topological insulator. The non-equilibrium magnon population established at the interface can decay in part by interactions of magnons with electrons near the Fermi energy of the topological insulator. When this decay channel is made active by tuning (BixSb1-x)2Te3 into a bulk insulator, a large electromotive force emerges in the direction perpendicular to the in-plane magnetization of yttrium iron garnet. The enhanced, tunable SSE which occurs when the Fermi level lies in the bulk gap offers unique advantages over the usual SSE in metals and therefore opens up exciting possibilities in spintronics.

  1. Enhancement of tunability of MAPK cascade due to coexistence of processive and distributive phosphorylation mechanisms.

    Science.gov (United States)

    Sun, Jianqiang; Yi, Ming; Yang, Lijian; Wei, Wenbin; Ding, Yiming; Jia, Ya

    2014-03-01

    The processive phosphorylation mechanism becomes important when there is macromolecular crowding in the cytoplasm. Integrating the processive phosphorylation mechanism with the traditional distributive one, we propose a mixed dual-site phosphorylation (MDP) mechanism in a single-layer phosphorylation cycle. Further, we build a degree model by applying the MDP mechanism to a three-layer mitogen-activated protein kinase (MAPK) cascade. By bifurcation analysis, our study suggests that the crowded-environment-induced pseudoprocessive mechanism can qualitatively change the response of this biological network. By adjusting the degree of processivity in our model, we find that the MAPK cascade is able to switch between the ultrasensitivity, bistability, and oscillatory dynamical states. Sensitivity analysis shows that the theoretical results remain unchanged within a reasonably chosen variation of parameter perturbation. By scaling the reaction rates and also introducing new connections into the kinetic scheme, we further construct a proportion model of the MAPK cascade to validate our findings. Finally, it is illustrated that the spatial propagation of the activated MAPK signal can be improved (or attenuated) by increasing the degree of processivity of kinase (or phosphatase). Our research implies that the MDP mechanism makes the MAPK cascade become a flexible signal module, and the coexistence of processive and distributive phosphorylation mechanisms enhances the tunability of the MAPK cascade. PMID:24606945

  2. Enhanced optical properties due to indium incorporation in zinc oxide nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Farid, S.; Mukherjee, S.; Sarkar, K.; Mazouchi, M. [Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Stroscio, M. A. [Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Dutta, M., E-mail: dutta@uic.edu [Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607 (United States)

    2016-01-11

    Indium-doped zinc oxide nanowires grown by vapor-liquid-solid technique with 1.6 at. % indium content show intense room temperature photoluminescence (PL) that is red shifted to 20 meV from band edge. We report on a combination of nanowires and nanobelts-like structures with enhanced optical properties after indium doping. The near band edge emission shift gives an estimate for the carrier density as high as 5.5 × 10{sup 19 }cm{sup −3} for doped nanowires according to Mott's critical density theory. Quenching of the visible green peak is seen for doped nanostructures indicating lesser oxygen vacancies and improved quality. PL and transmission electron microscopy measurements confirm indium doping into the ZnO lattice, whereas temperature dependent PL data give an estimation of the donor and acceptor binding energies that agrees well with indium doped nanowires. This provides a non-destructive technique to estimate doping for 1D structures as compared to the traditional FET approach. Furthermore, these indium doped nanowires can be a potential candidate for transparent conducting oxides applications and spintronic devices with controlled growth mechanism.

  3. Enhanced optical properties due to indium incorporation in zinc oxide nanowires

    Science.gov (United States)

    Farid, S.; Mukherjee, S.; Sarkar, K.; Mazouchi, M.; Stroscio, M. A.; Dutta, M.

    2016-01-01

    Indium-doped zinc oxide nanowires grown by vapor-liquid-solid technique with 1.6 at. % indium content show intense room temperature photoluminescence (PL) that is red shifted to 20 meV from band edge. We report on a combination of nanowires and nanobelts-like structures with enhanced optical properties after indium doping. The near band edge emission shift gives an estimate for the carrier density as high as 5.5 × 1019 cm-3 for doped nanowires according to Mott's critical density theory. Quenching of the visible green peak is seen for doped nanostructures indicating lesser oxygen vacancies and improved quality. PL and transmission electron microscopy measurements confirm indium doping into the ZnO lattice, whereas temperature dependent PL data give an estimation of the donor and acceptor binding energies that agrees well with indium doped nanowires. This provides a non-destructive technique to estimate doping for 1D structures as compared to the traditional FET approach. Furthermore, these indium doped nanowires can be a potential candidate for transparent conducting oxides applications and spintronic devices with controlled growth mechanism.

  4. Can the diphoton enhancement at 750 GeV be due to a neutral technipion?

    CERN Document Server

    Lebiedowicz, Piotr; Pasechnik, Roman; Szczurek, Antoni

    2016-01-01

    We discuss a scenario in which the diphoton enhancement at $M_{\\gamma \\gamma}$ = 750 GeV, observed by the ATLAS and CMS Collaborations, is a neutral technipion $\\tilde{\\pi}^0$. We consider two distinct minimal models for the dynamical electroweak symmetry breaking. In a first one, two-flavor vector-like technicolor (VTC) model, we assume that the two-photon fusion is a dominant production mechanism. We include $\\gamma \\gamma \\to {\\tilde \\pi}^0$ and production of technipion associated with one or two jets. All the considered mechanisms give similar contributions. With the strong Yukawa (technipion-techniquark) coupling $g_{TC}$ = 10 - 20 we obtain the measured cross section of the "signal". With such values of $g_{TC}$ we get a relatively small $\\Gamma_{\\rm tot}$. In a second approach, one-family walking technicolor (WTC) model, the isoscalar technipion is produced dominantly via the gluon-gluon fusion. We also discuss the size of the signal at lower energies (LHC, Tevatron) for $\\gamma \\gamma$ (VTC) and jet-j...

  5. Detection of Enhancement in Number Densities of Background Galaxies due to Magnification by Massive Galaxy Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, I. [Technical Univ. of Munich (Germany). et al.

    2015-10-06

    We present a detection of the enhancement in the number densities of background galaxies induced from lensing magnification and use it to test the Sunyaev-Zel'dovich effect (SZE) inferred masses in a sample of 19 galaxy clusters with median redshift z≃0.42 selected from the South Pole Telescope SPT-SZ survey. Two background galaxy populations are selected for this study through their photometric colours; they have median redshifts zmedian≃0.9 (low-z background) and zmedian≃1.8 (high-z background). Stacking these populations, we detect the magnification bias effect at 3.3σ and 1.3σ for the low- and high-z backgrounds, respectively. We fit NFW models simultaneously to all observed magnification bias profiles to estimate the multiplicative factor η that describes the ratio of the weak lensing mass to the mass inferred from the SZE observable-mass relation. We further quantify systematic uncertainties in η resulting from the photometric noise and bias, the cluster galaxy contamination and the estimations of the background properties. The resulting η for the combined background populations with 1σ uncertainties is 0.83±0.24(stat)±0.074(sys), indicating good consistency between the lensing and the SZE-inferred masses. We also use our best-fit η to predict the weak lensing shear profiles and compare these predictions with observations, showing agreement between the magnification and shear mass constraints. Our work demonstrates the promise of using the magnification as a complementary method to estimate cluster masses in large surveys.

  6. Enhancement of fusion rates due to quantum effects in the particles momentum distribution in nonideal media

    CERN Document Server

    Fisch, N J; Petrushevich, Yu V; Quarati, Piero; Starostin, A N

    2011-01-01

    This study concerns a situation when measurements of the nonresonant cross-section of nuclear reactions appear highly dependent on the environment in which the particles interact. An appealing example discussed in the paper is the interaction of a deuteron beam with a target of deuterated metal Ta. In these experiments, the reaction cross section for d(d,p)t was shown to be orders of magnitude greater than what the conventional model predicts for the low-energy particles. In this paper we take into account the influence of quantum effects due to the Heisenberg uncertainty principle for particles in a non-ideal medium elastically interacting with the medium particles. In order to calculate the nuclear reaction rate in the non-ideal environment we apply both the Monte Carlo technique and approximate analytical calculation of the Feynman diagram using nonrelativistic kinetic Green's functions in the medium which correspond to the generalized energy and momentum distribution functions of interacting particles. We...

  7. Disorder-assisted transmission due to charge puddles in monolayer graphene: Transmission enhancement and local currents

    Science.gov (United States)

    Lima, Leandro R. F.; Lewenkopf, Caio H.

    2016-01-01

    We investigate the contribution of charge puddles to the nonvanishing conductivity minimum in disordered graphene flakes at the charge neutrality point. For that purpose, we study systems with a geometry that suppresses the transmission due to evanescent modes allowing us to single out the effect of charge fluctuations in the transport properties. We use the recursive Green's function technique to obtain local and total transmissions through systems that mimic vanishing density of states at the charge neutrality point in the presence of a local disordered local potential to model the charge puddles. Our microscopic model includes electron-electron interactions via a spin resolved Hubbard mean field term. We establish the relationship between the charge puddle disorder potential and the electronic transmission at the charge neutrality point. We find that electronic interactions do not play a significant role in this setting. We discuss the implications of our findings to high mobility graphene samples deposited on different substrates and provide a qualitative interpretation of recent experimental results.

  8. Enhanced mass removal due to phase explosion during high irradiance nanosecond laser ablation of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jong Hyun

    2000-05-20

    The morphology of craters resulting from high irradiance laser ablation of silicon was measured using a white light interferometry microscope. The craters show a dramatic increase in their depth and volume at a certain irradiance, indicating a change in the primary mechanism for mass removal. Laser shadowgraph imaging was used to characterize and differentiate the mass ejection processes for laser irradiances above and below the threshold value. Time-resolved images show distinct features of the mass ejected at irradiances above the threshold value including the presence of micron-sized particulates; this begins at approximately 300 {approx} 400 ns after the start of laser heating. The analysis of the phenomena was carried out by using two models: a thermal evaporation model and a phase explosion model. Estimation of the crater depth due to the thermally evaporated mass led to a large underestimation of the crater depth for irradiances above the threshold. Above the threshold irradiance, the possibility of phase explosion was analyzed. Two important results are the thickness of the superheated liquid layer that is close to the critical temperature and the time for vapor bubbles that are generated in the superheated liquid to achieve a critical size. After reaching the critical size, vapor bubbles can grow spontaneously resulting in a violent ejection of liquid droplets from the superheated volume. The effects of an induced transparency, i.e. of liquid silicon turning into an optically transparent liquid dielectric medium, are also introduced. The estimated time for a bubble to reach the critical size is in agreement with the delay time measured for the initiation of large mass ejection. Also, the thickness of the superheated liquid layer that is close to the critical temperature at the time of the beginning of the large mass ejection is representative of the crater depth at the threshold irradiance. These results suggest that phase explosion is a plausible thermal

  9. The Technological Enhancement of Normally Occurring Radioactive Materials in Red Mud due to the Production of Alumina

    Directory of Open Access Journals (Sweden)

    Maurice O. Miller

    2016-01-01

    Full Text Available This study investigates the level of technological enhancement of normally occurring radioactive materials (TENORM in the red mud waste due to the production of alumina in Jamaica. Technological enhancements factors (TEF were determined for the uranium, thorium, actinium series, their progenies, and the nonseries potassium-40 using gamma spectrometry. The study concluded that bauxite production technologically enhances the uranium progenies Th-234, Pb-214, Bi-214, and Pa-234 and the thorium-232 progenies Ac-228, Pb-212, and Bi-212 in red mud. The actinium series was technologically enhanced, but K-40 and the thorium daughter, Tl-208, were reduced. The spectrometric comparison of Tl-208 (at 510 keV was unexpected since its other photopeaks at 583 keV, 934 keV, and 968 keV were markedly different. An explanation for this anomaly is discussed. An explanation regarding the process of accumulation and fractionation of organically derived phosphate deposits and potassium-feldspar is offered to explain the spectrometric differences between the alumina product and its waste material, red mud.

  10. Enhancement in electron and ion temperatures due to solar flares as measured by SROSS-C2 satellite

    Directory of Open Access Journals (Sweden)

    D. K. Sharma

    2004-06-01

    Full Text Available The observations on the ionospheric electron and ion temperatures (Te and Ti measured by the RPA payload aboard the SROSS-C2 satellite have been used to study the effect of solar flares on ionospheric heating. The data on solar flare has been obtained from the National Geophysical Data Center (NGDC Boulder, Colorado (USA. It has been found that the electron and ion temperatures have a consistent enhancement during the solar flares on the dayside Earth's ionosphere. The estimated enhancement for the average electron temperature is from 1.3 to 1.9 times whereas for ion temperature it is from 1.2 to 1.4 times to the normal days average temperature. The enhancement of ionospheric temperatures due to solar flares is correlated with the diurnal variation of normal days' ionospheric temperatures. The solar flare does not have any significant effect on the nightside ionosphere. A comparison with the temperature obtained from the IRI-95 model also shows a similar enhancement.

  11. Test of radiation damage enhancement due to incorporation of BrUdR into DNA using chromatid aberrations

    International Nuclear Information System (INIS)

    Monte Carlo track structure calculations, leading to an estimation of the magnitude of enhancement of radiation damage due to the incorporation of the halogenated pyrimidine, bromodeoxyuridine (BrUdR) a thymine analog, into DNA have been made. The increase in the yield of double strand breaks for various degrees of substitution in one (monofilarly) or both strands (bifilarly) have been calculated. To test these calculations, quantitative selected radiation-induced aberrations have been obtained in Chinese hamster (V79) fibroblast chromosomes having various patterns of BrUdR substitution following irradiation with 250 kV X rays. Free ''breaks'' and achromatic lesions ''gaps'' show no appreciable sensitizations, but breaks involved in chromatid interchanges show significant enhancement though of lower magnitude than theoretical predictions

  12. Broadband wide-angle absorption enhancement due to mode conversion in cold unmagnetized plasmas with periodic density variations

    CERN Document Server

    Yu, Dae Jung

    2016-01-01

    We study theoretically the mode conversion and the associated resonant absorption of p-polarized electromagnetic waves into longitudinal plasma oscillations in cold, unmagnetized and stratified plasmas with periodic spatial density variations. We consider sinusoidal density configurations for which the frequency band where mode conversion occurs is well included within a transmission band of the one-dimensional plasma photonic crystal. We calculate the mode conversion coefficient, which measures the fraction of the electromagnetic wave energy absorbed into the plasma, and the spatial distribution of the magnetic field intensity for various values of the wave frequency and the incident angle using the invariant imbedding theory of mode conversion. We find that the absorption is greatly enhanced over a wide range of frequency and incident angle due to the interplay between the mode conversion and the photonic band structure. The enhancement occurs because for frequencies within a transmission band, the wave ref...

  13. Photoluminescence Study of Enhanced Light Emission from HgCdTe Thin Films due to a Surface Pattern

    OpenAIRE

    Haugan, Espen Tunhøvd

    2015-01-01

    HgCdTe thin film samples with a CdTe passivation layer have been grown by molecular beam epitaxy, and photolithography has been used to etch a triangular pattern of holes into the passivation layer. The enhancement in light emission from the samples due to their surface pattern has been measured by means of photoluminescence spectroscopy (PL), giving values ranging from 31 % to 163 %. PL-measurements and simulations with both the transfer matrix method and the 3D finite-difference time d...

  14. Enhanced excitonic photoconductivity due to built-in internal electric field in TlGaSe{sub 2} layered semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Seyidov, MirHasan Yu., E-mail: smirhasan@gyte.edu.tr; Suleymanov, Rauf A. [Department of Physics, Gebze Institute of Technology, Gebze, Kocaeli 41400 (Turkey); Institute of Physics Azerbaijan National Academy of Sciences, AZ-1143 Baku (Azerbaijan); Şale, Yasin [Department of Physics, Gebze Institute of Technology, Gebze, Kocaeli 41400 (Turkey); Balaban, Ertan [Department of Physics, Gebze Institute of Technology, Gebze, Kocaeli 41400 (Turkey); TUBITAK-BILGEM, Scientific and Technical Research Council of Turkey, Gebze, Kocaeli 41470 (Turkey)

    2014-12-07

    The strong enhancement, by several orders of magnitude, of the excitonic peak within the photoconductivity spectrum of TlGaSe{sub 2} semiconductor was observed. The samples were polarized in external dc electric field, which was applied prior to the measurements. Due to the accumulation of charges near the surface, an internal electric field was formed. Electron-hole pairs that were created after the absorption of light are fallen in and then separated by the built-in electric field, which prevents radiative recombination process.

  15. Enhanced excitonic photoconductivity due to built-in internal electric field in TlGaSe2 layered semiconductor

    International Nuclear Information System (INIS)

    The strong enhancement, by several orders of magnitude, of the excitonic peak within the photoconductivity spectrum of TlGaSe2 semiconductor was observed. The samples were polarized in external dc electric field, which was applied prior to the measurements. Due to the accumulation of charges near the surface, an internal electric field was formed. Electron-hole pairs that were created after the absorption of light are fallen in and then separated by the built-in electric field, which prevents radiative recombination process

  16. Quarrying: an anthropogenic geomorphological approach

    International Nuclear Information System (INIS)

    The study intends to give an introduction to the significance of quarrying from the point of view of anthropogenic geomorphology, indicating the level of surface forming due to the mining of mineral raw materials. The significance of this topic is supported by the existence of the so-called 'mining landscapes' that emerged since to the 19th century. Authors focus on the geomorphic impact of quarrying with special emphasis on factors influencing its spatial distribution, as well as on the characteristics and classification of surface features produced by quarrying, providing an overview of the most important excavated and accumulated forms and form components, on the macro, meso and micro scales. Finally, international and Hungarian case studies illustrate some aspects of the opening and after-use of mining sites in order to observe how abandoned quarries can be turned into 'environmental values', and used as possible sites for exhibitions or for regional and tourism development projects. (author)

  17. Geoheritage, Geodiversity and natural landscape enhanced and protected through anthropogenic activity: a case study using the Chaîne des Puys and Limagne Fault, Afar and Mexico City

    Science.gov (United States)

    van Wyk de Vries, Benjamin; Hagos, Miruts; Guilbaud, Marie-Noelle

    2015-04-01

    The UNESCO World Heritage (WH) committee called in 2014 for all thematic geological and volcanological studies to be revised in light of a widening gap between current dogma and the progressive geoheritage science views. We discuss question of natural sites and anthropogenic activity. The Chaîne des Puys and Limagne fault UNESCO WH project is the basis of this presentation, but we also the Afar Region of Ethiopia and UNAM campus, Mexico City. It is now difficult to find any totally 'natural' (devoid of human influence) landscape. This very definition of natural ignores that humankind is a geological force, and humans are part of the natural process. The UNESCO WH guidelines recognise this in paragraph 90: 'it is recognized that no area is totally pristine and that all natural areas are in a dynamic state, and to some extent involve contact with people'. A geological landscape, may be large enough to accommodate human occupation without significantly changing landforms: this is the case of the Chaîne des Puys and Limagne fault. Human activity works in some ways to protect geological landscape: regulating vegetation and erosion. The aesthetic nature of humans may work to enhance the landscape's visibility by organisation of land use, and ceremonial use based on the sense of place. Humans also exercise economic activity such as quarrying and mining, which if uncontrolled can seriously modify a landscape. However, isolated works may not have an impact, or may even enhance the value of the site by uncovering geological features that would not naturally be seen. In the Chaîne des Puys only 0,3% of the land surface has been worked by artisanal methods and certain sites, like the Lemptégy volcano have been extracted with the view of enhancing the landscape's scientific value without detracting from the aesthetic. The site preserves its natural, scientific and aesthetic qualities, because of the human presence. The local population have always been and continue to be

  18. Improvement in the photocurrent collection due to enhanced absorption of light by synthesizing staggered layers of silver nanoclusters in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Dhoubhadel, Mangal S.; Lakshantha, Wickramaarachchige J.; Rout, Bibhudutta; McDaniel, Floyd D., E-mail: mcdaniel@unt.edu [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, Denton, Texas 76203 (United States); Lightbourne, Sherard; D’Souza, Francis [Department of Chemistry, University of North Texas, Denton, Texas 76203 (United States)

    2015-07-23

    The quest for increased efficiency of solar cells has driven the research in synthesizing photovoltaic cells involving Si based materials. The efficiency of solar cells involving crystalline Si is stalled around 25% for the last decade. Recently Shi et al. had shown that light trapping can be enhanced by fabricating double layers of Ag nanoparticles in silicon based materials. The light trapping is critically important in a photo devices such as solar cells in order to increase light absorption and efficiency. In the present work, we report enhancement in the absorption of light in Ag ion implanted Si substrates. Multiple low energies Ag ions, ranging from ∼80 keV to ∼30 keV, with different fluences ranging from ∼1 × 10{sup 16} to ∼1 × 10{sup 17} atoms/cm{sup 2} were sequentially implanted into commercially available Si (100) substrates followed by post-thermal annealing to create different sizes of Ag nanoclusters (NC) at different depths in the top 100 nm of the Si. The absorbance of light is increased in Ag implanted Si with a significant increase in the current collection in I-V (current-voltage) photo switching measurements. The experimental photovoltaic cells fabricated with the Ag-implanted Si samples were optically characterized under AM (air mass) 1.5 solar radiation conditions (∼1.0 kW/m{sup 2}). An enhancement in the charge collection were measured in the annealed samples, where prominent Ag NCs were formed in the Si matrix compared to the as-implanted samples with amorphous layers. We believe the enhancement of the photo-current density from the samples with Ag NC is due to the improvement of efficiency of charge collection of e{sup −}-h{sup +} pairs produced by the incident light.

  19. Improvement in the photocurrent collection due to enhanced absorption of light by synthesizing staggered layers of silver nanoclusters in silicon

    International Nuclear Information System (INIS)

    The quest for increased efficiency of solar cells has driven the research in synthesizing photovoltaic cells involving Si based materials. The efficiency of solar cells involving crystalline Si is stalled around 25% for the last decade. Recently Shi et al. had shown that light trapping can be enhanced by fabricating double layers of Ag nanoparticles in silicon based materials. The light trapping is critically important in a photo devices such as solar cells in order to increase light absorption and efficiency. In the present work, we report enhancement in the absorption of light in Ag ion implanted Si substrates. Multiple low energies Ag ions, ranging from ∼80 keV to ∼30 keV, with different fluences ranging from ∼1 × 1016 to ∼1 × 1017 atoms/cm2 were sequentially implanted into commercially available Si (100) substrates followed by post-thermal annealing to create different sizes of Ag nanoclusters (NC) at different depths in the top 100 nm of the Si. The absorbance of light is increased in Ag implanted Si with a significant increase in the current collection in I-V (current-voltage) photo switching measurements. The experimental photovoltaic cells fabricated with the Ag-implanted Si samples were optically characterized under AM (air mass) 1.5 solar radiation conditions (∼1.0 kW/m2). An enhancement in the charge collection were measured in the annealed samples, where prominent Ag NCs were formed in the Si matrix compared to the as-implanted samples with amorphous layers. We believe the enhancement of the photo-current density from the samples with Ag NC is due to the improvement of efficiency of charge collection of e−-h+ pairs produced by the incident light

  20. Direct radiative effects of anthropogenic aerosols on Indian summer monsoon circulation

    Science.gov (United States)

    Das, Sushant; Dey, Sagnik; Dash, S. K.

    2016-05-01

    The direct radiative impacts of anthropogenic aerosols on the dynamics of Indian summer monsoon circulation are examined using the regional climate model version 4.1 (RegCM4.1). High anthropogenic aerosol optical depth (AAOD >0.1) and surface shortwave cooling (0.2 °C due to the dimming effect of anthropogenic aerosols. The aerosol-induced cooling leads to an increase in surface pressure over the local hotspots in the Indian landmass, which reduces the land-sea pressure contrast resulting in weakening of summer monsoon circulation. The simulated surface pressure anomaly also inhibits moisture transport from the BoB towards Indian landmass thereby enhancing precipitation over the BoB and parts of the east coast of India. The impacts are interpreted as conservative estimates because of the underestimation of AAOD by the model due to uncertainties in emission inventory and biases in simulated meteorology. Our results demonstrate the direct radiative impacts of anthropogenic aerosols on the Indian monsoon circulation and call for future studies combining the dynamical and microphysical impacts, which are not considered in this study.

  1. Impacts of anthropogenic and natural sources on free tropospheric ozone over the Middle East

    Science.gov (United States)

    Jiang, Z.; Miyazaki, K.; Worden, J. R.; Liu, J. J.; Jones, D. B. A.; Henze, D. K.

    2015-12-01

    Significant progress has been made in identifying the influence of different processes and emissions on the summertime enhancements of free tropospheric ozone (O3) at northern mid-latitude regions. However, the exact contribution of regional emissions and chemical processing to these summertime enhancements is still not well quantified. Here we focus on quantifying the influence of regional emissions on the summertime O3 enhancements over the Middle East. We use updated reactive nitrogen (NOx) emissions from an ensemble Kalman Filter that assimilates satellite observations of nitrogen dioxide (NO2), O3, and carbon monoxide (CO) to provide an improved estimate of O3 precursor emissions. We then use the adjoint of the GEOS-Chem model with these updated NOx emissions to show that the global total contribution of lightning NOx on middle free tropospheric O3 over the Middle East is about three times larger than that from global anthropogenic sources. The summertime free tropospheric O3 enhancement is primarily due to Asian NOx emissions, with approximately equivalent contributions from Asian anthropogenic activities and lightning. In the Middle Eastern lower free troposphere, emissions from European and North American anthropogenic activities and from lightning NOx are the primary sources of O3. This work highlights the critical role of lightning NOx on northern mid-latitude free tropospheric O3 and the important effect of the Asian summer monsoon on the export of Asian pollutants.

  2. Anthropogenic effect on avalanche and debris flow activity

    Directory of Open Access Journals (Sweden)

    S. A. Sokratov

    2015-04-01

    Full Text Available The paper presents examples of the change in snow avalanches and debris flows activity due to the anthropogenic pressure on vegetation and relief. The changes in dynamical characteristics of selected snow avalanches and debris flows due to the anthropogenic activity are quantified. The conclusion is made that the anthropogenic effects on the snow avalanches and debris flows activity are more pronounced than the possible effects of the climate change. The necessity is expressed on the unavoidable changes of the natural environment as the result of a construction and of use of the constructed infrastructure to be account for in corresponding planning of the protection measures.

  3. Enhanced formation of secondary air pollutants and aggravation of urban smog due to crop residue burning emissions in North India

    Science.gov (United States)

    Sarkar, Chinmoy; Kumar, Vinod; Sinha, Vinayak

    2013-04-01

    Biomass burning causes intense perturbations to regional atmospheric chemistry and air quality and is a significant global source of reactive pollutants to the atmosphere (Andreae and Merlet, 2001). In November 2012, large areas in North India including New Delhi experienced several weeks of aggravated smog and poor air quality due to the impact of crop residue burning, which is a biannual post harvest activity that occurs during Oct-Nov and April-May every year in the agricultural belts of North western India. In-situ high temporal resolution (1 measurement every minute) measurements of a suite of volatile organic compounds measured using proton transfer reaction mass spectrometry (PTR-MS) such as acetonitrile (biomass burning tracer) and aromatic hydrocarbons were performed simultaneously with carbon monoxide, nitrogen oxides, ozone and aerosol mass concentrations (PM 2.5 and PM 10) at a suburban site (30.667°N, 76.729°E and 310 m asl), impacted by air masses that had passed over the burning fields less than 72 hours ago. By using data from the same season but before the post harvest crop residue burning activity had commenced, we were able to quantify enhancements in ambient levels of the measured species due to the crop residue burning activity. When air masses influenced by the fire emissions reached the measurement site, peak values of about 8 ppbV acetonitrile, 4 ppmV CO, 100 ppbV NOx , 30 ppbV toluene and 15 ppbV benzene were observed which represented a factor of 2-5 increase over their ambient levels in the non-fire influenced period. Emission ratios of aromatic hydrocarbons/CO also showed a marked increase. Non fire event (N.F. E.) influenced and fire event (F.E.) influenced air masses had the following emission ratio enhancements: benzene/CO (N.F.E = 3; F.E. = 5), toluene/CO (N.F.E = 4; F.E. = 8.7) and sum of C8 aromatics/CO (N.F.E = 4; F.E. = 7.3) and sum of C9 aromatics/CO (N.F.E = 2.6; F.E. = 3.4). The OH reactivity of air masses which has strong

  4. Renal transplant failure due to urologic complications: Comparison of static fluid with contrast-enhanced magnetic resonance urography

    International Nuclear Information System (INIS)

    Purpose: Postrenal reasons of renal transplant failure can be assessed by magnetic resonance urography. This study was designed to retrospectively compare the diagnostic accuracy of static fluid (T2-)MRU compared to contrast enhanced (CE-)MRU in patients with renal transplant failure. Material and methods: Thirty-five consecutive patients (14 female, 21 men; mean age 48.6 years) with renal transplant failure and sonographically detected hydronephrosis were examined both with T2-MRU as well as CE-MRU resulting in 39 MRU examinations. MRU was performed both using T2-weighted HASTE-sequence (T2-MRU) as well as Gadolinium-enhanced 3D-FLASH-sequence (CE-MRU) on a 1.5-T clinical MRI scanner (Magnetom Vision, Siemens Medical Solutions). Subjective image quality of resulting maximum intensity projection was assessed in consensus by two readers blinded to the final diagnosis, using a five point scale. MRU findings were correlated to sonography, operative results or clinical follow up. Results: CE-MRU yielded a sensitivity of 85.7% (T2-MRU 76.2%), and a specificity of 83.3% (T2-MRU: 73.7%), however statistical significance was not reached. The subjective image quality was significantly better in CE-MRU. Conclusions: Only concerning subjective image quality CE-MRU proved superior to T2-MRU. Yet, there was no significant difference in diagnostic accuracy between T2- and CE-MRU. Thinking of incipient nephrogenic systemic fibrosis, T2-MRU can be used as reliable alternative in patients with decreased renal transplant function due to urological complications

  5. Renal transplant failure due to urologic complications: Comparison of static fluid with contrast-enhanced magnetic resonance urography

    Energy Technology Data Exchange (ETDEWEB)

    Blondin, D. [University Hospital Duesseldorf, Institute of Diagnostic Radiology, Moorenstr. 5, D-40225 Duesseldorf (Germany)], E-mail: blondin@med.uni-duesseldorf.de; Koester, A.; Andersen, K.; Kurz, K.D.; Moedder, U.; Cohnen, M. [University Hospital Duesseldorf, Institute of Diagnostic Radiology, Moorenstr. 5, D-40225 Duesseldorf (Germany)

    2009-02-15

    Purpose: Postrenal reasons of renal transplant failure can be assessed by magnetic resonance urography. This study was designed to retrospectively compare the diagnostic accuracy of static fluid (T2-)MRU compared to contrast enhanced (CE-)MRU in patients with renal transplant failure. Material and methods: Thirty-five consecutive patients (14 female, 21 men; mean age 48.6 years) with renal transplant failure and sonographically detected hydronephrosis were examined both with T2-MRU as well as CE-MRU resulting in 39 MRU examinations. MRU was performed both using T2-weighted HASTE-sequence (T2-MRU) as well as Gadolinium-enhanced 3D-FLASH-sequence (CE-MRU) on a 1.5-T clinical MRI scanner (Magnetom Vision, Siemens Medical Solutions). Subjective image quality of resulting maximum intensity projection was assessed in consensus by two readers blinded to the final diagnosis, using a five point scale. MRU findings were correlated to sonography, operative results or clinical follow up. Results: CE-MRU yielded a sensitivity of 85.7% (T2-MRU 76.2%), and a specificity of 83.3% (T2-MRU: 73.7%), however statistical significance was not reached. The subjective image quality was significantly better in CE-MRU. Conclusions: Only concerning subjective image quality CE-MRU proved superior to T2-MRU. Yet, there was no significant difference in diagnostic accuracy between T2- and CE-MRU. Thinking of incipient nephrogenic systemic fibrosis, T2-MRU can be used as reliable alternative in patients with decreased renal transplant function due to urological complications.

  6. Detection of anthropogenic dust using CALIPSO lidar measurements

    Science.gov (United States)

    Huang, J. P.; Liu, J. J.; Chen, B.; Nasiri, S. L.

    2015-10-01

    Anthropogenic dusts are those produced by human activities on disturbed soils, which are mainly cropland, pastureland, and urbanized regions, and are a subset of the total dust load which includes natural sources from desert regions. Our knowledge of anthropogenic dusts is still very limited due to a lack of data. To understand the contribution of anthropogenic dust to the total global dust load, it is important to identify it apart from total dust. In this study, a new technique for distinguishing anthropogenic dust from natural dust is proposed by using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) dust and planetary boundary layer (PBL) height retrievals along with a land use data set. Using this technique, the global distribution of dust is analyzed and the relative contribution of anthropogenic and natural dust sources to regional and global emissions are estimated. Results reveal that local anthropogenic dust aerosol due to human activity, such as agriculture, industrial activity, transportation, and overgrazing, accounts for about 25 % of the global continental dust load. Of these anthropogenic dust aerosols, more than 53 % come from semi-arid and semi-wet regions. Annual mean anthropogenic dust column burden (DCB) values range from 0.42 g m-2, with a maximum in India, to 0.12 g m-2, with a minimum in North America. A better understanding of anthropogenic dust emission will enable us to focus on human activities in these critical regions and with such knowledge we will be more able to improve global dust models and to explore the effects of anthropogenic emission on radiative forcing, climate change, and air quality in the future.

  7. Enhanced Proton Beam Focusing due to Proximal Target Structures on the 1.25 kJ OMEGA EP Laser

    Science.gov (United States)

    McGuffey, Chris; Kim, J.; Qiao, B.; Beg, F. N.; Wei, M. S.; Fitzsimmons, P.; Evans, M.; Stephens, R. B.; Fuchs, J.; Chen, S. N.; Nilson, P. M.; Canning, D.; Mastrosimone, D.; Foord, M. E.; McLean, H. S.

    2013-10-01

    Understanding how to generate and control laser-driven proton beams has shown significant progress in the last 15 years. However, to exploit promising applications, practical aspects must be addressed, such as the effect of structures holding the target and dynamics when the beam enters any sample. Using the 1.25 kJ, 10 ps OMEGA EP BL laser and spherically curved C targets we studied the spot size of a high-density proton beam directed at a Cu foil using three target mounting configurations: 1 on a stalk, 2 with an open-sided wedge structure on the back, and 3 with a conical structure. The brightness of Cu Kα fluorescence from the center of the foil was weakest from the stalk-mounted target, 5x brighter with the wedge, and 8x brighter with the cone, indicating enhanced focusing due to the structures. Plasma features and fields from the interaction were temporally and spatially resolved using proton radiography from a separate broad-spectrum proton beam (0-40 MeV) driven by OMEGA EP SL. We also discuss a follow-on experiment that will study transport of the proton beam through various materials. This work was supported by the DOE/NNSA NLUF program, Grant DE-NA0002034.

  8. Anthropogenic effects on interaction outcomes: examples from insect-microbial symbioses in forest and savanna ecosystems

    DEFF Research Database (Denmark)

    Six, Diana L.; Thomas-Poulsen, Michael; Hansen, Allison K.;

    2011-01-01

    to anthropogenic change. Most organisms are involved in at least one mutualism, and many in several. Mutualisms facilitate the ability of partners to exploit particular habitats and resources, and play a large role in determining ecological boundaries. When change disrupts, enhances, or introduces new organisms...... into a mutualism, the outcome and stability of the original partnership(s) is altered as are effects of the symbiosis on the community and ecosystem as a whole. In this paper, using examples from six microbe-insect mutualisms in forest and savanna settings, we showcase how varied and complex the responses...... of mutualisms can be to an equally varied set of anthropogenic influences. We also show how alterations of mutualisms may ramify throughout affected systems. We stress that researchers must be cognizant that many observed changes in the behaviors, abundances, and distributions of organisms due to human...

  9. Proinflammatory and Th1 cytokine alterations following ultraviolet radiation enhancement of disease due to influenza infection in mice.

    Science.gov (United States)

    Ryan, Lisa K; Copeland, Lisa R; Daniels, Mary J; Costa, Elisabeth R; Selgrade, Mary Jane K

    2002-05-01

    Exposure of rodents to immunosuppressive agents such as ozone, dioxin, or ultraviolet radiation (UVR) leads to increased morbidity and mortality following influenza virus infection. However, these adverse effects are not related to the suppression of virus-specific immune responses. Our laboratory showed that UVR increased the morbidity, mortality, and pathogenesis of influenza virus without affecting protective immunity to the virus, as measured by resistance to reinfection, suggesting that UVR and other immunosuppressive pollutants such as dioxin and ozone may exacerbate early responses that contribute to the pathogenesis of a primary viral infection. In the present study, we examined the mechanism of UVR-enhanced mortality in the absence of effects on virus-specific immunity and tested the hypothesis that modulation of cytokine levels was associated with increased deaths and body weight loss. BALB/c mice were exposed to 8.2 kJ/m(2) UVR and were infected 3 days later with a sublethal influenza virus infection (LD(40) of mouse-adapted Hong Kong influenza A/68, H(3)N(2)). Influx of inflammatory cells, proinflammatory cytokines, and cytokines produced by T-helper lymphocytes (Th1 and Th2) were measured in lung homogenates (LH) as well as in bronchoalveolar lavage fluid (BAL). UVR preexposure decreased the influenza-induced lymphocytic influx 5 days after infection, but did not alter macrophage and neutrophil influx into the lung, or increase virus titers significantly. Although interferon (IFN)-gamma, total interleukin (IL)-12, IL-6, and TNF-alpha were altered in mice that received UVR exposure prior to infection, no clear association was made that correlated with the UVR-induced increase in body weight loss and mortality due to influenza infection. PMID:11961220

  10. Extreme Wave Simulation due to Typhoon Bolaven based on locally Enhanced Fine-Mesh Unstructured Grid Model

    Science.gov (United States)

    Kim, Kyeong Ok; Choi, Byung Ho; Jung, Kyung Tae

    2016-04-01

    The performance of an integrally coupled wave-tide-surge model using the unstructured mesh system has been tested for the typhoon Bolaven which is regarded as the most powerful storm to strike the Korean Peninsula in nearly a decade with wind gusts measured up to 50 m/s, causing serious damages with 19 victims. Use of the unstructured mesh in coastal sea regions of marginal scale allows all energy from deep to shallow waters to be seamlessly followed; the physics of wave-circulation interactions can be then correctly resolved. The model covers the whole Yellow and East China Seas with locally refined meshes near the regions of Gageo Island (offshore southwestern corner of the Korean Peninsula) and south of Jeju Island (Gangjeong and Seogwipo ports). The wind and pressure fields during the passage of typhoon Bolaven are generated by the blending method. Generally the numerical atmospheric model cannot satisfactorily reproduce the strength of typhoons due to dynamic and resolution restrictions. In this study we could achieve an improved conservation of the typhoon strength by blending the Holland typhoon model result by the empirical formula onto the ambient meteorological fields of NCEP dataset. The model results are compared with the observations and the model performance is then evaluated. The computed wave spectrums for one and two dimensions are compared with the observation in Ieodo station. Results show that the wind wave significantly enhances the current intensity and surge elevation, addressing that to incorporate the wave-current interaction effect in the wave-tide-surge coupled model is important for the accurate prediction of current and sea surface elevation as well as extreme waves in shallow coastal sea regions. The resulting modeling system can be used for hindcasting and forecasting the wave-tide-surges in marine environments with complex coastlines, shallow water depth and fine sediment.

  11. Highly enhanced green emission from InGaN quantum wells due to surface plasmon resonance on aluminum films

    Energy Technology Data Exchange (ETDEWEB)

    Tateishi, Kazutaka; Okamoto, Koichi, E-mail: okamoto@ms.ifoc.kyushu-u.ac.jp; Tamada, Kaoru [Institute for Materials Chemistry and Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Funato, Mitsuru; Kawakami, Yoichi [Department of Electronic Science and Engineering, Kyoto University, Katsura Campus, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2015-03-23

    Photoluminescence (PL) from InGaN/GaN quantum wells was highly enhanced by the surface plasmon (SP) resonance on aluminum thin films. The enhancement ratio of green emission reached 80, which was much larger than the previously reported enhancements on silver films. The resulting large enhancement should be attributed to an ∼20-fold enhancement of the excitation efficiency and ∼4-fold enhancement of the emission efficiency by the excitation and emission spectra. The temperature dependence of the PL intensities and the time-resolved PL measurements were also performed to understand the detailed mechanism. We concluded that the resonance between the excitation light and the SP on the Al surface should improve the excitation efficiency, i.e., the light absorption efficiency. This result suggests that the Al films have an extraordinary photon confinement effect, which are unique properties of plasmonics with Al and should be useful for new and wider applications.

  12. Potential climatic effects of anthropogenic aerosols

    International Nuclear Information System (INIS)

    Aerosols act as part of the climate system through their influence on solar and terrestrial radiation. The effect of anthropogenic aerosols on the reduction of visibility is explored in this chapter. Elemental carbon has been identified as the most effective visibility-reducing species. Most of the visibility reduction is due to particles with diameter smaller than 2.5 μm. Studies indicate that sulfate is also a very important aerosol species that results in low visibility and high turbidity. Radiative properties such as aerosol single-scattering albedo values and absorption-to-backscatter ratios purported to produce warming or cooling effects of aerosols are discussed. It is concluded that aerosol clouds have a tendency to cool when they are over a low-albedo surface and have a tendency to warm when they are over high-albedo surfaces such as snow. Anthropogenic aerosols have a tendency to warm the earth's atmospheric system, based on calculations and assumed aerosol optical properties. However, this effect is somewhat offset by the absorption and re-emission into space of infrared terrestrial radiation. The net effect depends on the ratio of the absorption coefficients in the visible and infrared and also on the surface albedo. The effects on infrared radiation are documented for two anthropogenic aerosol sources in the United States, the Denver metropolitan area and power plant plumes in New Mexico, through calculations and measurements. Measured cooling rates within an aerosol plume are not sufficient to offset the warming rate due to absorption of short-wave radiation. Research indicates that anthropogenic aerosols can possibly cause local-scale warming of the atmosphere, but global-scale climatic effects remain an open question

  13. Anthropogenic mercury emissions in China

    Science.gov (United States)

    Streets, David G.; Hao, Jiming; Wu, Ye; Jiang, Jingkun; Chan, Melissa; Tian, Hezhong; Feng, Xinbin

    An inventory of mercury emissions from anthropogenic activities in China is compiled for the year 1999 from official statistical data. We estimate that China's emissions were 536 (±236) t of total mercury. This value includes open biomass burning, but does not include natural sources or re-emission of previously deposited mercury. Approximately 45% of the Hg comes from non-ferrous metals smelting, 38% from coal combustion, and 17% from miscellaneous activities, of which battery and fluorescent lamp production and cement production are the largest. Emissions are heaviest in Liaoning and Guangdong Provinces, where extensive smelting occurs, and in Guizhou Province, where there is much small-scale combustion of high-Hg coal without emission control devices. Emissions are gridded at 30×30 min spatial resolution. We estimate that 56% of the Hg in China is released as Hg 0, 32% as Hg 2+, and 12% as Hg p. Particulate mercury emissions are high in China due to heavy burning of coal in residential and small industrial settings without PM controls. Emissions of Hg 2+ from coal-fired power plants are high due to the absence of flue-gas desulfurization units, which tend to dissolve the soluble divalent mercury. Metals smelting operations favor the production of elemental mercury. Much of the Hg is released from small-scale activities in rather remote areas, and therefore the activity levels are quite uncertain. Also, emissions test data for Chinese sources are lacking, causing uncertainties in Hg emission factors and removal efficiencies. Overall, we calculate an uncertainty level of ±44% (95% confidence interval) in the estimate of total emissions. We recommend field testing of coal combustors and smelters in China to improve the accuracy of these estimates.

  14. Observational estimates of planetary albedo changes due to anthropogenic effects /

    OpenAIRE

    Pistone, Kristina

    2014-01-01

    A major driver of both the Earth's natural climate variability and current climate change is the net solar input to the Earth system, i.e. the amount of incident solar radiation minus the fraction reflected back to space. Changes in this so-called albedo may have substantial effects on the Earth's climate. I use observations to address aspects of both the Arctic sea ice -albedo feedback and the albedo effects of aerosols on Indian Ocean cumulus clouds. In Chapter 2, I use satellite radiation ...

  15. Attribution of irreversible loss to anthropogenic climate change

    Science.gov (United States)

    Huggel, Christian; Bresch, David; Hansen, Gerrit; James, Rachel; Mechler, Reinhard; Stone, Dáithí; Wallimann-Helmer, Ivo

    2016-04-01

    The Paris Agreement (2015) under the UNFCCC has anchored loss and damage in a separate article which specifies that understanding and support should be enhanced in areas addressing loss and damage such as early warning, preparedness, insurance and resilience. Irreversible loss is a special category under loss and damage but there is still missing clarity over what irreversible loss actually includes. Many negative impacts of climate change may be handled or mitigated by existing risk management, reduction and absorption approaches. Irreversible loss, however, is thought to be insufficiently addressed by risk management. Therefore, countries potentially or actually affected by irreversible loss are calling for other measures such as compensation, which however is highly contested in international climate policy. In Paris (2015) a decision was adopted that loss and damage as defined in the respective article of the agreement does not involve compensation and liability. Nevertheless, it is likely that some sort of mechanism will eventually need to come into play for irreversible loss due to anthropogenic climate change, which might involve compensation, other forms of non-monetary reparation, or transformation. Furthermore, climate litigation has increasingly been attempted to address negative effects of climate change. In this context, attribution is important to understand the drivers of change, what counts as irreversible loss due to climate change, and, possibly, who or what is responsible. Here we approach this issue by applying a detection and attribution perspective on irreversible loss. We first analyze detected climate change impacts as assessed in the IPCC Fifth Assessment Report. We distinguish between irreversible loss in physical, biological and human systems, and accordingly identify the following candidates of irreversible loss in these systems: loss of glaciers and ice sheets, loss of subsurface ice (permafrost) and related loss of lake systems; loss

  16. On the fate of anthropogenic nitrogen

    OpenAIRE

    Schlesinger, William H.

    2008-01-01

    This article provides a synthesis of literature values to trace the fate of 150 Tg/yr anthropogenic nitrogen applied by humans to the Earth's land surface. Approximately 9 TgN/yr may be accumulating in the terrestrial biosphere in pools with residence times of ten to several hundred years. Enhanced fluvial transport of nitrogen in rivers and percolation to groundwater accounts for ≈35 and 15 TgN/yr, respectively. Greater denitrification in terrestrial soils and wetlands may account for the lo...

  17. Possibilities of anthropogenic variations of thunderstorm activity

    International Nuclear Information System (INIS)

    The possibilities of anthropogenic modifications of thunderstorm activity are investigated. Different approaches were used to estimate the number of thunderstorms that could be modified by anthropogenic heat rejection. As a result it was found that about 50 percent of the thunderstorms occurring annually over the Swiss plateau or the area around the city of Basel offer the potential of an anthropogenic modification. On the basis of simplified physical models, the energy-flux to start a medium thunderstorm is estimated to be about 0.01 - 0.1 GW, if the energy is available as kinetic energy, and about 100 GW for thermal energy. Computer simulations with a parcel model confirm these orders of magnitude. The model calculations indicate also, that the power required to start a small thunderstorm under especially critical (unstable) weather situations can be an order of magnitude smaller than the above values. Comparing the required 100 GW thermal starting energy-flux with a single dry or wet 2 GW cooling tower suggests, that for climatic conditions typical for Switzerland, the formation of a thunderstorm due to cooling tower heat rejection is a very unlikely event. Power parks consisting of 30 - 50 dry cooling towers rejecting 2 GW each would be required to severely modify thunderstorm activity in their surroundings. About 5 to 10 cooling towers concentrated at one site would probably be a critical limit. When exceeded, modifications of thunderstorm activity seem to become climatologically significant. (Auth.)

  18. Quantifying solubility enhancement due to particle size reduction and crystal habit modification: case study of acetyl salicylic acid.

    Science.gov (United States)

    Hammond, Robert B; Pencheva, Klimentina; Roberts, Kevin J; Auffret, Tony

    2007-08-01

    The poor solubility of potential drug molecules is a significant problem in the design of pharmaceutical formulations. It is well known, however, that the solubility of crystalline materials is enhanced when the particle size is reduced to submicron levels and this factor can be expected to enhance drug product bioavailability. Direct estimation of solubility enhancement, as calculated via the Gibbs-Thompson relationship, demands reasonably accurate values for the particle/solution interfacial tension and, in particular, its anisotropy with respect to the crystal product's habit and morphology. In this article, an improved, more molecule-centered, approach is presented towards the calculation of solubility enhancement factors in which molecular modeling techniques are applied, and the effects associated with both crystal habit modification and solvent choice are examined. A case study for facetted, acetyl salicylic acid (aspirin) crystals in equilibrium with saturated aqueous ethanol solution reveals that their solubility will be enhanced in the range (7-58%) for a crystal size of 0.02 microm, with significantly higher enhancement for crystal morphologies in which the hydrophobic crystal faces are more predominant than the hydrophilic faces and for solvents in which the solubility is smaller. PMID:17323349

  19. Addison's disease due to adrenal tuberculosis: Contrast-enhanced CT features and clinical duration correlation

    Energy Technology Data Exchange (ETDEWEB)

    Guo Yingkun [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Yang Zhigang [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China) and National Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China)]. E-mail: zgyang888@yahoo.com; Li Yuan [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Ma Ensen [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Deng Yuping [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Min Pengqiu [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Yin Longlin [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Hu Jian [Department of Stomatology, Dental Hospital, Wuhan University, Wuhan, Hubei 502310 (China); Zhang Xiaochun [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Chen Tianwu [Department of Radiology, West China Hospital, Sichuan University, 37 Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

    2007-04-15

    Purpose: To describe CT morphology of untreated adrenal tuberculosis during the different stages of the natural history of the disease and to evaluate the diagnostic implications of CT features. Materials and methods: We retrospectively evaluated CT features in 42 patients with documented adrenal tuberculosis for the location, size, morphology, and enhancement patterns shown on CT images. The clinical duration were correlated with the CT features. Results: Of the 42 patients with untreated adrenal tuberculosis, bilaterally enlarged adrenal glands were revealed in 38 cases (91%), unilaterally enlarged in 3 cases (7%), and normal size in 1 case (2%). Of the 41 cases (98%) with enlargement, mass-like enlargement was seen in 20 cases (49%) and enlargement with preserved contours in 21 cases (51%). Peripheral rim enhancement presented in 22 cases (52%) on contrast-enhanced CT. Non-enhanced CT scan revealed calcification in 21 cases (50%). As the duration of Addison's disease increased, the presence of calcification and contour preservation increased concomitantly (p < 0.001), whereas peripheral rim enhancement and mass-like enlargement decreased concomitantly on CT images (p < 0.001). Conclusion: CT may be helpful in diagnosing adrenal tuberculosis when clinically suspected, and CT features are correlated to the clinical duration of Addison's disease.

  20. Anthropogenic Elevation Change in the Pacific Northwest

    Science.gov (United States)

    Prush, V. B.; Lohman, R. B.

    2013-12-01

    Over the past few decades, interferometric synthetic aperture radar (InSAR) has emerged as a valuable tool for studying crustal deformation signals. Its applications to studies of tectonic and non-tectonic sources are varied, including earthquakes and fault-related processes, volcanic deformation, vegetation structure, and anthropogenic signals. In addition to studies of crustal deformation, the sensitivity of interferometric phase to topography makes InSAR a superb tool for the generation of digital elevation models (DEMs). While much of the focus of InSAR research in recent years has been on deformation, changes in the elevation of the ground surface can be of great scientific or societal interest as well. Examples include elevation and volume change due to anthropogenic processes such as landfill and open-pit mining operations, and natural processes such as glacier thinning or terrain alteration resulting from effusive volcanic eruptions. Our study describes two elevation change signals observed in the Pacific Northwest that are of anthropogenic origin. Using the baseline-dependent nature of the topographic component of interferometric phase, we have determined a proxy for canopy height using coherent interferometric phase differences between adjacent logged and forested regions, as well as a means for determining estimates of the amount and time history of material displaced during mining operations at the Centralia Coal Mine in Centralia, Washington. Quantifying the amount of surface change due to anthropogenic activities is not only critical for tracking the altering landscape of the Pacific Northwest and reducing the observed error in interferograms attributable to elevation change. Deforestation is one of the most significant contributors to global carbon emissions, and quantifying changes in vegetation structure can assist in efforts to monitor and mitigate the effects of deforestation on climate change. Similarly, mining operations can have a lasting

  1. Observation of pitting due to field enhanced surface absorption during laser assisted cleaning of translucent particulates off metal surfaces

    International Nuclear Information System (INIS)

    Highlights: ► Laser assisted cleaning. ► Field enhanced surface absorption. ► Experimental evidence of surface pitting. - Abstract: The field enhanced surface absorption that occurs as a result of focusing of the incident radiation through transparent/semi-transparent contaminant particulates, in addition to their removal, can also leave its signature on the surface in the form of pitting. This has been experimentally verified in case of removal of CsNO3 particulates off stainless steel surface with sub-nanosecond to nanosecond pulses of 1064 nm, 532 nm, and 355 nm wavelengths for which the particulates are semi-transparent. The threshold fluence for such pit formation has been studied as a function of both wavelength and pulse duration of the coherent radiation and was always found to be much higher than the cleaning threshold. Qualitative explanations have been offered to the observed experimental results.

  2. Experimental Investigation On The Enhancement In Thermosyphon Effect Due To Insertion Of Twisted Strips Inside A Duct

    Directory of Open Access Journals (Sweden)

    S. V. Prayagi

    2011-08-01

    Full Text Available The present work deals with experimental studies on heat transfer and flow characteristic for buoyancy induced flow through inclined tubes inserted with twisted strips. The parameters varied during the experimetation are; tube inclination , heat supply and twist pitch. It was found that the percentage enhancement in heat transfer coefficient decreases with increase in pitch parameters and tube inclination.The flow rate decreases for lower values of pitch parameters and increase in the tube inclination.

  3. Inventory of anthropogenic mercury emission Southwest China: I. Guizhou province

    International Nuclear Information System (INIS)

    The anthropogenic emissions of mercury to air is considered to contribute by 50-75 % of the total, and is thus responsible for elevated mercury concentration in the global atmosphere. These elevated atmospheric levels may be a serious threat to terrestrial and aquatic ecosystems due to wet or dry deposition. Hence, measures must be taken in controlling the anthropogenic emissions of mercury. A fundamental step of a global mercury control is realistic mapping of anthropogenic and natural emissions. Today, reasonably well documented mercury emission inventories of anthropogenic point sources exist in Europe and North America. The amount of anthropogenic emissions in other parts of the world is quite uncertain, as well as world-wide diffuse emissions (anthropogenic and natural). Guizhou is situated on a plateau with a mean altitude of about 1000 m. Its climate is a typical subtropical humid monsoon with an average annual temperature of 15 dec C and a precipitation of 1100-1400 mm. The province accounts for about 2.8% of the total population in China. (orig.)

  4. Effects of species loss and nutrients on biodiversity:Anthropogenic impacts on marine biodiversity: effects of enhanced nutrients and species loss on the biodiversity and ecosystem functioning of rocky shores

    OpenAIRE

    O'Connor, Nessa; Crowe, T.P.

    2012-01-01

    The focus of this study was to disentangle the effects of multiple stressors on biodiversity, ecosystem functioning and stability. This project examined the effects of anthropogenic increased nutrient loads on the diversity of coastal ecosystems and the effects of loss of species on ecosystem functioning. Specifically, the direct effect of sewage outfalls on benthic communities was assessed using a fully replicated survey that incorporated spatial and temporal variation. In addition, two fiel...

  5. Enhanced photoluminescence due to two-photon enhanced three-photon absorption in Mn{sup 2+}-doped ZnS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Subha, Radhu [Department of Physics, Indian Institute of Technology, Madras, Chennai, 600036, India and Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore, 117542 (Singapore); Nalla, Venkatram; Ji, Wei, E-mail: phyjiwei@nus.edu.sg [Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore, 117542 (Singapore); Feng, Xiaobo [School of Physics and Electronic Information Technology, Yunnan Normal University (China); Vijayan, C. [Department of Physics, Indian Institute of Technology, Madras, Chennai, 600036 (India)

    2014-10-15

    In this work, we have investigated the multi-photon absorption induced photoluminescence in Mn{sup 2+}-doped ZnS quantum dots in the wavelength range 860 – 1050 nm (Near-Infrared Window I). The observed three-photon action cross-section has been compared with the theoretical prediction under four band approximation. An enhancement of four to five orders has been observed in the range from 970 to 1050 nm compared to the theoretical value, which is attributed to two-photon enhanced three-photon absorption. Transient lifetime measurements reveal a lifetime of 0.35 ± 0.3 ms, which is four to five orders higher than other conventional fluorescent probes.

  6. Enhanced cadmium cytotoxicity in A549 cells with reduced glutathione levels is due to neither enhanced cadmium accumulation nor reduced metallothionein synthesis

    International Nuclear Information System (INIS)

    Glutathione (GSH) depletion sensitizes human lung carcinoma (A549-T27) cells to the cytotoxic effects of Cd++. The effects of GSH depletion on Cd++ accumulation and Cd++-induced metallothionein (MT) content were investigated to determine the possible role of these Cd++ responses in the sensitization process. Cellular GSH was depleted to 20% to 25% of control levels with buthionine sulfoximine (BSO), or diethyl maleate (DEM), respectively. Neither treatment significantly affected Cd++-induced accumulation of exogenous 35s-cysteine into intracellular MT in a dose-dependent fashion. The results indicate that neither enhanced Cd++ accumulation nor reduced MT synthesis plays a primary role in affecting enhanced Cd++ cytotoxicity in A549 cells with reduced GSH levels. Although BSO inhibition of GSH synthesis enhanced MT synthesis, it sensitized the cells to Cd++, which suggests an additive effect of GSH and MT in cadmium cytoprotection. This observation also raises the possibility that intracellular cysteine levels limit Cd++-induced MT accumulation rates

  7. Consideration Of The Change Of Material Emission Signatures Due To Long-term Emissions For Enhancing Voc Source Identification

    DEFF Research Database (Denmark)

    Han, K. H.; Zhang, J. S.; Knudsen, H. N.; Wargocki, Pawel; Guo, B.

    2011-01-01

    The objectives of this study were to characterize the changes of VOC material emission profiles over time and develop a method to account for such changes in order to enhance a source identification technique that is based on the measurements of mixed air samples and the emission signatures of...... individual building materials determined by PTRMS. Source models, including powerlaw model, doubleexponential decay model and mechanistic diffusion model, were employed to track the change of individual material emission signatures by PTRMS over a ninemonth period. Samples of nine typical building materials...

  8. Radiation-enhanced short channel effects due to multi-dimensional influence from charge at trench isolation oxides

    Energy Technology Data Exchange (ETDEWEB)

    Youk, G.U.; Khare, P.S.; Schrimpf, R.D.; Massengill, L.W.; Galloway, K.F.

    1999-12-01

    Radiation enhanced drain induced barrier lowering (DIBL) was experimentally observed and verified by 3-D simulations for submicron devices with trench isolation oxides. Submicron MOSFETs with shallow trench isolation were exposed to total-ionizing-dose radiation. Prior to irradiation, the devices exhibited near-ideal current-voltage characteristics, with no significant short-channel effects for as-drawn gate lengths of 0.4 {micro}m. Following irradiation, the off-state leakage current increased significantly for total doses above about 650 krad(SiO{sub 2}). In addition, the irradiated devices exhibited DIBL that increased the drain current by 5--10x for a gate length of 0.4 {micro}m (the nominal minimum gate length for this process) and much more for slightly shorter devices (0.35 {micro}m). The increase in the off-state leakage current and the accompanying DIBL are shown to be associated with a parasitic field-effect transistor that is present at the edge of the shallow trench. Three-dimensional simulations are used to illustrate the effect. Simulations show that trapped charge at the trench sidewalls enhance the DIBL by depleting the edges of the channel. Radiation-induced charge may decrease the effectiveness of short-channel engineering.

  9. Enhanced photoelectrochemical performance of WO3/Ti photoanode due to in situ formation of a thin interfacial composite layer

    Science.gov (United States)

    Lee, Won Jae; Shinde, Pravin S.; Go, Geun Ho; Doh, Chil Hoon

    2013-04-01

    Nanostructured WO3 thin films were prepared on titanium sheet substrates using a doctor blade technique. X-ray diffraction, Raman and field emission scanning electron microscopy studies revealed that the synthesized WO3 films are having monoclinic crystal structure, porous, polycrystalline with average grain size of ∼50 nm. The photoelectrochemical responses of WO3 films prepared on treated Ti sheets were recorded in 0.5 M H2SO4 electrolyte under simulated 100 mW/cm2 illumination. WO3 film prepared on polished Ti sheet showed considerable enhancement in photocurrent as compared to WO3 films made on unpolished and pre-oxidized Ti sheets. These results suggest that in situ formation of a thin WOx-TiOy interfacial composite layer and improved adhesion of WO3 nanoparticles owing to increased reactive sites on polished Ti substrate play a significant role in enhancing the photoresponse. Such photoanodes are potential candidates in photoelectrochemical water splitting system for hydrogen generation.

  10. Enhanced emission and photoconductivity due to photo-induced charge transfer from Au nanoislands to ZnO

    International Nuclear Information System (INIS)

    We report systematic studies based on photoluminescence, Hall, and photoconductivity measurements together with theoretical modeling in order to identify mechanisms for the photo-induced charge transfer effects in ZnO thin film incorporated with the Au nano-islands (AuNIs). Significant enhancement of near band edge emission and improvement in conductivity of ZnO/AuNIs samples after illumination are observed, which are attributed to the photo-induced hot electrons in Au which are then transferred into the conduction band of ZnO as long as the excitation energy is higher than the offset between the ZnO conduction-band minimum and Au Fermi level. Our experimental results are consistent with the general features predicted by first principles calculations

  11. Enhanced emission and photoconductivity due to photo-induced charge transfer from Au nanoislands to ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shang-Hsuan; Chan, Ching-Hsiang; Liang, Ching-Tarng [Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan (China); Chien, Ching-Hang; Yaseen, Mohammad Tariq [Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan (China); Nano Science and Technology Program, TIGP, Academia Sinica, Taipei 115, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Chang, Yia-Chung, E-mail: yiachang@gate.sinica.edu.tw [Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan (China); Department of Physics, National Cheng Kung University, Tainan 701, Taiwan (China)

    2016-01-25

    We report systematic studies based on photoluminescence, Hall, and photoconductivity measurements together with theoretical modeling in order to identify mechanisms for the photo-induced charge transfer effects in ZnO thin film incorporated with the Au nano-islands (AuNIs). Significant enhancement of near band edge emission and improvement in conductivity of ZnO/AuNIs samples after illumination are observed, which are attributed to the photo-induced hot electrons in Au which are then transferred into the conduction band of ZnO as long as the excitation energy is higher than the offset between the ZnO conduction-band minimum and Au Fermi level. Our experimental results are consistent with the general features predicted by first principles calculations.

  12. Evidence for the enhancement of stress induced ordering in a Ag27 at.% Zn alloy due to electron irradiation

    International Nuclear Information System (INIS)

    Damping studies of the Zener relaxation in an Ag.27 at.% Zn alloy have been conducted by use of an inverted torsion pendulum working in line with a 2 MeV accelerator. The internal friction spectrum traced during bombardment in a flux of 1.5.10sup13e-/cm2s, in the temperature range 50 to 250degC (0.3-0.5Tsub(m)), indicates an increase in the rate of the Zener relaxation relative to that of nonirradiated specimens. The excess concentration of point defects associated with this enhanced relaxation rate is discussed within the frame of the models which describe the steady state defect supersaturation existing under flux

  13. Enhancement of Rashba interaction in GaAs/AlGaAs quantum wells due to the incorporation of bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, R. A.; Jin, S. R.; Sweeney, S. J.; Clowes, S. K. [Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2015-10-05

    This paper reports on the predicted increase in the Rashba interaction due to the incorporation of Bi in GaAs/AlGaAs heterostructures. Band structure parameters obtained from the band anti-crossing theory have been used in combination with self-consistent Schrödinger-Poisson calculations and k.p models to determine the electron spin-splitting caused by structural inversion asymmetry and increased spin-orbit interaction. A near linear seven fold increase in the strength of the Rashba interaction is predicted for a 10% concentration of Bi in a GaAsBi/AlGaAs quantum well heterostructure.

  14. Enhanced Light Emission due to Formation of Semi-polar InGaN/GaN Multi-quantum Wells.

    Science.gov (United States)

    Zhao, Wan-Ru; Weng, Guo-En; Wang, Jian-Yu; Zhang, Jiang-Yong; Liang, Hong-Wei; Sekiguchi, Takashi; Zhang, Bao-Ping

    2015-12-01

    InGaN/GaN multi-quantum wells (MQWs) are grown on (0001) sapphire substrates by metal organic chemical vapor deposition (MOCVD) with special growth parameters to form V-shaped pits simultaneously. Measurements by atomic force microscopy (AFM) and transmission electron microscopy (TEM) demonstrate the formation of MQWs on both (0001) and ([Formula: see text]) side surface of the V-shaped pits. The latter is known to be a semi-polar surface. Optical characterizations together with theoretical calculation enable us to identify the optical transitions from these MQWs. The layer thickness on ([Formula: see text]) surface is smaller than that on (0001) surface, and the energy level in the ([Formula: see text]) semi-polar quantum well (QW) is higher than in the (0001) QW. As the sample temperature is increased from 15 K, the integrated cathodoluminescence (CL) intensity of (0001) MQWs increases first and then decreases while that of the ([Formula: see text]) MQWs decreases monotonically. The integrated photoluminescence (PL) intensity of (0001) MQWs increases significantly from 15 to 70 K. These results are explained by carrier injection from ([Formula: see text]) to (0001) MQWs due to thermal excitation. It is therefore concluded that the emission efficiency of (0001) MQWs at high temperatures can be greatly improved due to the formation of semi-polar MQWs. PMID:26625883

  15. Estimation of dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiothearpy - A phantom dosimetric study with radiochromic film

    Directory of Open Access Journals (Sweden)

    Rajesh Ashok Kinhikar

    2014-01-01

    Full Text Available The objective of this study was to investigate the dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiotherapy. The influence of titanium-mandibular plate with the screws on radiation dose was tested on four real bones from mandible with the metal and screws fixed. Radiochromic films were used for dosimetry. The bone and metal were inserted through the film at the center symmetrically. This was then placed in a small jig (7 cm × 7 cm × 10 cm to hold the film vertically straight. The polymer granules (tissue-equivalent were placed around the film for homogeneous scatter medium. The film was irradiated with 6 MV X-rays for 200 monitor units in Trilogy linear accelerator for 10 cm × 10 cm field size with source to axis distance of 100 cm at 5 cm. A single film was also irradiated without any bone and metal interface for reference data. The absolute dose and the vertical dose profile were measured from the film. There was 10% dose enhancement due to the backscatter radiation just adjacent to the metal-bone interface for all the materials. The extent of the backscatter effect was up to 4 mm. There is significant higher dose enhancement in the soft tissue/skin due to the backscatter radiation from the metallic components in the treatment region.

  16. Estimation of dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiotherapy - a phantom dosimetric study with radiochromic film

    International Nuclear Information System (INIS)

    The objective of this study was to investigate the dose enhancement to soft tissue due to backscatter radiation near metal interfaces during head and neck radiotherapy. The influence of titanium-mandibular plate with the screws on radiation dose was tested on four real bones from mandible with the metal and screws fixed. Radiochromic films were used for dosimetry. The bone and metal were inserted through the film at the center symmetrically. This was then placed in a small jig (7 cm × 7 cm × 10 cm) to hold the film vertically straight. The polymer granules (tissue-equivalent) were placed around the film for homogeneous scatter medium. The film was irradiated with 6 MV X-rays for 200 monitor units in Trilogy linear accelerator for 10 cm × 10 cm field size with source to axis distance of 100 cm at 5 cm. A single film was also irradiated without any bone and metal interface for reference data. The absolute dose and the vertical dose profile were measured from the film. There was 10% dose enhancement due to the backscatter radiation just adjacent to the metal-bone interface for all the materials. The extent of the backscatter effect was up to 4 mm. There is significant higher dose enhancement in the soft tissue/skin due to the backscatter radiation from the metallic components in the treatment region. (author)

  17. The impact of North American anthropogenic emissions and lightning on long-range transport of trace gases and their export from the continent during summers 2002 and 2004

    KAUST Repository

    Martini, Matus

    2011-04-07

    We analyze the contribution of North American (NA) lightning and anthropogenic emissions to ozone concentrations, radiative forcing, and export fluxes from North America during summers 2002 and 2004 using the University of Maryland Chemical Transport Model (UMD-CTM) driven by GEOS-4 reanalysis. Reduced power plant emissions (NOx SIP Call) and cooler temperatures in 2004 compared to 2002 resulted in lower ambient ozone concentrations over the eastern United States. Lightning flash rates in early summer 2004 were 50% higher than 2002 over the United States. Over the North Atlantic, changes in ozone column between early summer 2002 and 2004 due to changes in lightning and meteorology exceeded the change due to emission reductions by a factor of 7. Late summer changes in lightning had a much smaller impact on ozone columns. In summer 2004, net downward radiative flux at the tropopause due to ozone produced from anthropogenic emissions ranged from 0.15 to 0.30 W m−2 across the North Atlantic, while that due to ozone produced from lightning NO emissions ranged from 0.20 to 0.50 W m−2. Enhanced lofting of polluted air followed by stronger westerly winds led to more net export of NOx, NOy, and ozone in early summer 2004 than 2002 despite reduced anthropogenic emissions. Ozone export fluxes across the eastern NA boundary due to anthropogenic emissions were factors of 1.6 and 2 larger than those due to lightning in 2004 and 2002, respectively. Doubling the NA lightning NO source increased downwind ozone enhancements due to lightning NO emissions by one third.

  18. Anthropogenic influence on forest landscape in the Khumbu valley, Nepal

    Science.gov (United States)

    Lingua, Emanuele; Garbarino, Matteo; Urbinati, Carlo; Carrer, Marco

    2013-04-01

    High altitude Himalayan regions are geo-dynamically very active and very sensitive to natural and anthropogenic disturbances due to their steep slopes, variations of precipitations with elevation and short growing periods. Nonetheless, even in this remote region human pressure is often the most important factor affecting forest landscape. In the last decades the firewood demand has increased each year between September to December. The increase in the number of tourists, mountaineering, guides, porters, carpenters, lodges lead to a peak in the use of fuelwood. In order to understand anthropogenic impacts on forest, resources landscape and stand scale dynamics were analyzed in the Sagarmatha National Park (SNP) and its Buffer Zone in the Khumbu Valley (Nepal, Eastern Himalaya). Biological and historical data sources were employed, and a multi-scale approach was adopted to capture the influence of human activities on the distribution of tree species and forest structure. Stand structure and a range of environmental variables were sampled in 197 20x20 m square plots, and land use and anthropogenic variables were derived in a GIS environment (thematic maps and IKONOS, Landsat and Terra ASTER satellite images). We used multivariate statistical analyses to relate forest structure, anthropogenic influences, land uses, and topography. Fuel wood is the prime source of energy for cooking (1480-1880 Kg/person/year) and Quercus semecarpifolia, Rhododendron arboreum and Pinus wallichiana, among the others, are the most exploited species. Due to lack of sufficient energy sources deforestation is becoming a problem in the area. This might be a major threat causing soil erosion, landslides and other natural hazards. Among the 25 species of trees that were found in the Buffer Zone Community Forests of SNP, Pinus wallichiana, Lyonia ovalifolia, Quercus semecarpifolia and Rhododendron arboreum are the dominant species. The total stand density ranged from 228 to 379 tree/ha and the

  19. Enhanced photocatalytic activity of ultra-high aspect ratio ZnO nanowires due to Cu induced defects

    Science.gov (United States)

    Pasupathi Sugavaneshwar, Ramu; Duy Dao, Thang; Nanda, Karuna Kar; Nagao, Tadaaki; Hishita, Shunichi; Sakaguchi, Isao

    2015-12-01

    We report the synthesis of ZnO nanowires in ambient air at 650°C by a single-step vapor transport method using two different sources Zn (ZnO nanowires-I) and Zn:Cu (ZnO nanowires-II). The Zn:Cu mixed source co-vaporize Zn with a small amount of Cu at temperatures where elemental Cu source does not vaporize. This method provides us a facile route for Cu doping into ZnO. The aspect ratio of the grown ZnO nanowires-II was found to be higher by more than five times compared ZnO nanowires-I. Photocatalytic activity was measured by using a solar simulator and its ultraviolet-filtered light. The ZnO nanowires-II shows higher catalytic activity due to increased aspect ratio and higher content of surface defects because of incorporation of Cu impurities.

  20. Problems of anthropogenic tritium limitation

    Directory of Open Access Journals (Sweden)

    Kochetkov О.A.

    2013-12-01

    Full Text Available This article contains the current situation in respect to the environmental concentrations of anthropogenic and natural tritium. There are presented and analyzed domestic standards for НТО of all Radiation Safety Standards (NRB, as well as the regulations analyzed for tritium in drinking water taken in other countries today. This article deals with the experience of limitation of tritium and focuses on the main problem of rationing of tritium — rationing of organically bound tritium.

  1. Anthropogenic desertification by high-albedo pollution Observations and modeling

    Science.gov (United States)

    Otterman, J.; Rosenberg, N. W.; Rosenberg, E.

    1974-01-01

    ERTS-1 MSS albedo data of Western Negev, Sinai and the Gaza strip are presented. A sharp contrast in albedo exists across the Negev-Sinai and Negev-Gaza strip borders. Anthropogenic desertification has occurred on the Arab side due to overgrazing and Bedouin agriculture, whereas natural vegetation grows much more abundantly on the Israeli side.

  2. Changes in the micro-circulation of skeletal muscle due to varied isometric exercise assessed by contrast-enhanced ultrasound

    International Nuclear Information System (INIS)

    Purpose: To quantitatively assess local muscle micro-circulation with real-time contrast-enhanced ultrasound (CEUS) during different exercises and compare the results with performed muscle work and global blood flow. Materials and methods: Sixteen low mechanical index CEUS examinations of the right lower leg flexors of healthy volunteers were performed using a continuous infusion of SonoVue (4.8 mL/300 s). Several muscle perfusion parameters were extracted from derived CEUS signal intensity time curves during different isometric exercises (10-50% of maximum individual strength for 20-30 s) and then correlated with the performed muscle work or force, and the whole lower leg blood flow which we measured simultaneously by venous occlusion plethysmography (VOP). Results: The shapes of the CEUS curve during and after exercise differed individually depending on the performed muscle work. The maximum blood volume MAX was observed only after exercise cessation and was significantly correlated with the performed muscle force (r = 0.77, p < 0.0001). The blood volume over exercise time was inversely correlated with the spent muscle work (r = -0.60, p = 0.006). CEUS and VOP measurements correlated only at rest and after the exercise. During exercise, mean CEUS local blood volume decreased (from 3.48 to 2.19 (∼mL)), while mean VOP global blood flow increased (mean, from 3.96 to 7.71 mL/100 mg/min). Conclusion: Real-time low-MI CEUS provides complementary information about the local muscle micro-circulation compared to established blood flow measures. CEUS may be used for a better understanding of muscle perfusion physiology and in the diagnosis of micro-circulation alterations such as in peripheral arterial occlusive disease or diabetic angiopathy.

  3. Effects of East Asian Short-lived Anthropogenic Air Pollutants on the Northern Hemispheric Air Quality and Climate

    Science.gov (United States)

    Liu, J.; Horowitz, L. W.; Lau, N.; Fan, S.; Tao, S.; Mauzerall, D. L.; Levy, H.

    2012-12-01

    Short-lived anthropogenic pollutants (such as ozone and aerosols) not only degrade ambient air quality and influence human health, but also play an important role in scattering/absorbing atmospheric radiation and disturbing regional climate. Due to the rapid industrialization, anthropogenic emissions from East Asia (EA) have increased substantially during the past decades. At the same time, EA has experienced a changing climate in terms of surface temperature and precipitation. In order to understand to what extent that EA short-lived anthropogenic emissions could influence domestic and downwind air quality (e.g. surface O3 and PM2.5), and explore the potential linkage between hemispheric-scale climate perturbation and regional anthropogenic forcing, we simulate global climate and chemical compositions during 1981-2000 based on the coupled general circulation model CM3 for atmosphere (with interactive tropospheric and stratospheric chemistry), oceans, land and sea ice, recently developed at Geophysical Fluid Dynamics Laboratory (GFDL/NOAA). We also conduct a parallel sensitivity simulation which is identical to the base simulation but with all anthropogenic emissions over EA turned off. The difference between the base and sensitivity simulations represents the short-term response of the Northern Hemispheric climate system and atmospheric composition to the perturbation of regional anthropogenic forcing. We find that East Asian short-lived anthropogenic emissions exert significant adverse impacts on local air quality during 1981-2000, accounting for 10-30ppbV daily-averaged O3 over Eastern China in JJA. In particular, EA anthropogenic emissions elevate the summertime daily maximum 8-hour average ozone (MDA8 O3) by 30-40ppbV over the North China Plain, where the typical background MDA8 ozone ranges 30 to 45ppbV. In addition, the surface PM2.5 concentrations peak at the same season and over the same region, with a seasonal mean of 10-30ug/m3, mostly contributed from

  4. Corrosion due to use of carbon dioxide for enhanced oil recovery. Final report. SumX No. 78-003

    Energy Technology Data Exchange (ETDEWEB)

    DeBerry, D.W.; Clark, W.S.

    1979-09-01

    This study documents the specific effects of CO/sub 2/ on corrosion and identifies promising methods for controlling corrosion in fields using CO/sub 2/ injection. Information has been assembled on: CO/sub 2/ corrosion problems in general, surface and downhole corrosion problems specifically associated with CO/sub 2/ enhanced oil recovery, and methods to reduce corrosion problems in CO/sub 2/ environments. Corrosion mechanisms, kinetic behavior, and the effects of various parameters on corrosion by CO/sub 2/ are presented in this study. Engineering metals are not attacked by CO/sub 2/ under oil field environments unless liquid water is also present. Plain and low alloy steels are attacked by mixtures of CO/sub 2/ and liquid water. Attack on these bare metals may become serious at a CO/sub 2/ partial pressure as low as 4 psi and it increases with CO/sub 2/ partial pressure although not in direct proportion. Fluid flow rate is an important factor in CO/sub 2//water corrosion. Practically all stainless steels and similar resistant alloys are not particularly subject to corrosion by CO/sub 2//water mixtures alone, even at high CO/sub 2/ pressures. Elevated levels of CO/sub 2/ can aggravate the corrosive effects of other species such as hydrogen sulfide, oxygen, and chloride. Mixtures of CO/sub 2/, carbon monoxide (CO), and water can cause stress corrosion cracking of plain steels. Corrosion problems in CO/sub 2/ systems should be circumvented when possible by avoiding combination of the corrosive components. Although water cannot be excluded throughout the CO/sub 2/ injection-oil production-CO/sub 2/ and water reinjection chain, air in-leakage can be minimized and oxygen scavengers used to remove any residual. Exclusion of oxygen is important to the successful use of other corrosion control measures. A discussion is given of the main control methods including metal selection, protective coatings and nonmetallic materials, and chemical inhibition. (DLC)

  5. Performance Enhancement due to the TNL Congestion Control on the Simultaneous Deployment of both HSDPA and HSUPA

    Directory of Open Access Journals (Sweden)

    Yasir Zaki

    2010-07-01

    Full Text Available the main focus of the work presented in this paper is to analyze the effect of the Transport Network Layer (TNL congestion control on the High Speed Packet Access (HSPA performance. The TNL and in particular the Iub link needs to be carefully dimensioned. Firstly because it has significant impact on the end-to-end and network performance and secondly due to the high number of required links in the network, the Iub is a major cost factor for the network operators. The congestion control function works together with the air interface scheduler and Hybrid Automatic Repeat Request (HARQ in order to control the offered load to the TNL network. In this manner, the data flow over the TNL is adequately adapted to the user’s air interface data rate and to the available TNL capacity avoiding congestion in the transport network. In addition, the paper focuses as well on the effects of the simultaneous deployment of both High Speed Downlink and Uplink Packet Access (HSDPA & HSUPA. This is done by comparing the results from deploying HSDPA or HSUPA separately in the system against the simultaneous deployment of both (To the best of our knowledge, there are only few publications in which this has been investigated, especially in combination with the Congestion Control. The reason for such a comparison is to highlight the effects that appear when both are deployed together, since most of the previous studies were focusing only on either HSDPA or HSUPA, whereas the final goal is to use both together in one system. The simulation results presented in this paper confirm that the congestion in the transport network can be controlled in such a way that the available TNL capacity can be effectively utilized and hence the performance of HSPA network can be significantly improved in all aspects. In the ComNets TZI working group at the university of Bremen, a number of projects focusing on the TNL dimensioning and TNL features development for the HSPA network are

  6. Bifunctional enhancement of oxygen reduction reaction activity on Ag catalysts due to water activation on LaMnO3 supports in alkaline media

    Science.gov (United States)

    Park, Shin-Ae; Lee, Eun-Kyung; Song, Hannah; Kim, Yong-Tae

    2015-08-01

    Ag is considered to be one of the best candidates for oxygen reduction reaction electrocatalysts in alkaline media for application in various electrochemical energy devices. In this study, we demonstrate that water activation is a key factor in enhancing the ORR activity in alkaline media, unlike in acid environments. Ag supported on LaMnO3 having a high oxophilicity showed a markedly higher ORR activity than that on carbon with inert surfaces. Through various electrochemical tests, it was revealed that the origin of the enhanced ORR activity of Ag/LaMnO3 is the bifunctional effect mainly due to the water activation at the interface between Ag and LaMnO3. Furthermore, the ligand effect due to the charge transfer from Mn to Ag leads to the enhancement of both oxygen activation on Ag and water activation on Mn sites, and hence, an improvement in the ORR activity of Ag/LaMnO3. On the other hand, the strain effect based on the fine structure variation in the lattice was negligible. We therefore suggest that the employment of a co-catalyst or support with highly oxophilic nature and the maximization of the interface between catalyst and support should be considered in the design of electrocatalysts for the ORR in alkaline media.

  7. Biogenic emissions of isoprenoids and NO in China and comparison to anthropogenic emissions

    International Nuclear Information System (INIS)

    southern China, there are relatively large biogenic emissions of isoprenoids, leading to an important impact on the ozone production in these regions. Furthermore, the emissions of isoprenoids are highest during summer and noontime, which correlates to the peak of ozone production period. For example, the ratio between summer and winter for the emissions of isoprenoids is about 15 in China. As a result, the biogenic emissions of isoprenoids are significantly larger than the anthropogenic emissions of VOCs in China during daytime in summer. Biogenic NO emissions are mostly produced by agricultural soils which co-exist with large populations and human activity. As a result, the biogenic emissions of NO are mostly overlapped with the anthropogenic emissions of NO, leading to the enhancement in NO concentrations in the high anthropogenic NO emission regions. Finally, the future emissions of isoprene and monoterpenes over China are estimated. The results show that the future biogenic emissions may increase significantly due to land cover changes in central eastern China, which could have a very important impact on ozone formation in this region. However, these estimates are highly uncertain and are presented as a potential scenario to show the importance of possible changes of biogenic emissions in China

  8. Anthropogenic sulfur dioxide emissions: 1850–2005

    Directory of Open Access Journals (Sweden)

    S. J. Smith

    2011-02-01

    Full Text Available Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850–2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

  9. Anthropogenic sulfur dioxide emissions: 1850–2005

    Directory of Open Access Journals (Sweden)

    S. J. Smith

    2010-06-01

    Full Text Available Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850–2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

  10. Delivery of anthropogenic bioavailable iron from mineral dust and combustion aerosols to the ocean

    Directory of Open Access Journals (Sweden)

    A. Ito

    2015-08-01

    Full Text Available Atmospheric deposition of anthropogenic soluble iron (Fe to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. Here, we, for the first time, interactively combined laboratory kinetic experiments with global aerosol modeling to more accurately quantify anthropogenic soluble Fe due to air pollution. We firstly examined Fe dissolution kinetics of African dust samples at acidic pH values with and without ionic species commonly found in aerosol water (i.e., sulfate and oxalate. We then constructed a new empirical scheme for Fe release from mineral dust due to inorganic and organic anions in aerosol water, by using acidity as a master variable. We implemented this new scheme and applied an updated mineralogical emission database in a global atmospheric chemistry transport model to estimate the atmospheric concentration and deposition flux of soluble Fe under preindustrial and modern conditions. Our improved model successfully captured the inverse relationship of Fe solubility and total Fe loading measured over the North Atlantic Ocean (i.e., 1–2 orders of magnitude lower Fe solubility in North African- than combustion-influenced aerosols. The model results show a positive relationship between Fe solubility and water soluble organic carbon (WSOC/Fe molar ratio, which is consistent with previous field measurements. We estimated that deposition of soluble Fe to the ocean increased from 0.05–0.07 Tg Fe yr−1 in preindustrial era to 0.11–0.12 Tg Fe yr−1 in present days, due to air pollution. Over the High Nitrate Low Chlorophyll (HNLC regions of the ocean, the modeled Fe

  11. Delivery of anthropogenic bioavailable iron from mineral dust and combustion aerosols to the ocean

    Science.gov (United States)

    Ito, A.; Shi, Z.

    2016-01-01

    Atmospheric deposition of anthropogenic soluble iron (Fe) to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. In this study, for the first time, we interactively combined laboratory kinetic experiments with global aerosol modeling to more accurately quantify anthropogenic soluble Fe due to air pollution. Firstly, we determined Fe dissolution kinetics of African dust samples at acidic pH values with and without ionic species commonly found in aerosol water (i.e., sulfate and oxalate). Then, by using acidity as a master variable, we constructed a new empirical scheme for Fe release from mineral dust due to inorganic and organic anions in aerosol water. We implemented this new scheme and applied an updated mineralogical emission database in a global atmospheric chemistry transport model to estimate the atmospheric concentration and deposition flux of soluble Fe under preindustrial and modern conditions. Our improved model successfully captured the inverse relationship of Fe solubility and total Fe loading measured over the North Atlantic Ocean (i.e., 1-2 orders of magnitude lower Fe solubility in northern-African- than combustion-influenced aerosols). The model results show a positive relationship between Fe solubility and water-soluble organic carbon (WSOC)/Fe molar ratio, which is consistent with previous field measurements. We estimated that deposition of soluble Fe to the ocean increased from 0.05-0.07 Tg Fe yr-1 in the preindustrial era to 0.11-0.12 Tg Fe yr-1 in the present day, due to air pollution. Over the high-nitrate, low-chlorophyll (HNLC) regions of the ocean, the modeled Fe

  12. Understanding the regional anthropogenic signature in weakening of the south Asian Summer Monsoon

    Science.gov (United States)

    TP, S.

    2014-12-01

    The evidence from observation shows that South Asia underwent a widespread drying from the last five to six decades during the summer. The underlying reasons are unclear, whether this trend is due to natural or anthropogenic activities. Using a state-of-the-art global variable resolution climate model with high-resolution zooming over South-Asia, we decomposed the regional factors responsible for the weakening of monsoon circulation and rainfall. To address this issue we conducted several long simulations from 1886 to 2095, with and without anthropogenic forcing. The simulation provides key information about the regional responses to changes in south Asian summer monsoon, which leads to the decline in mean monsoon, and enhancement in the occurrence of localized extreme precipitation events in a warming climate. Further the 21st century climate projection using the same high-resolution model indicates persistent decrease of monsoonal rains due to land-atmosphere feedbacks in a warming environment. This would have severe impacts on agriculture, water resources and ecosystem over South Asia.

  13. Anthropogenic Actinides in the Environment

    International Nuclear Information System (INIS)

    The use of nuclear energy and the testing of nuclear weapons have led to significant releases of anthropogenic isotopes, in particular a number of actinide isotopes generally not abundant in nature. Most prominent amongst these are 239Pu, 240Pu, and 236U. The study of these actinides in nature has been an active field of study ever since. Measurements of actinides are applied to nuclear safeguards, investigating the sources of contamination, and as a tracer for a number of erosion and hydrology studies. Accelerator Mass Spectrometry (AMS) is ideally suited for these studies and generally offers higher sensitivities than competing techniques, like ICP-MS or decay counting. Recent advances in AMS allow the study of “minor” plutonium isotopes (241Pu, 242Pu, and 244Pu). Furthermore, 236U can now be measured at the levels expected from the global stratospheric fall-out of the atmospheric nuclear weapon tests in the 1950s and 1960s. Even the pre-anthropogenic isotope ratios could be within reach. However, the distribution and abundance levels of these isotopes are not well known yet. I will present an overview of the field, and in detail two recent studies on minor plutonium isotopes and 236U, respectively.(author)

  14. Anthropogenic radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Weng, J; Wang, J

    2007-11-15

    Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview of anthropogenic radionuclide contamination in the environment, as well as the salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current development that contribute to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) commercial fuel reprocessing; (5) geological repository of high-level nuclear wastes, and (6) nuclear accidents. Then, we summarize the geochemical behavior for radionuclides {sup 99}Tc, {sup 129}I, and {sup 237}Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment. Biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

  15. Magnetization enhancement due to incorporation of non-magnetic nitrogen content in (Co84Zr16)Nx nano-composite films

    International Nuclear Information System (INIS)

    We report the magnetic, electronic, and structural properties of nano-composite (Co84Zr16)Nx or CZN films prepared by reactive co-sputter deposition method. As-deposited CZN films have shown enhancement in magnetization (Ms) with incorporation of nitrogen content, which is related to the evolution of nano-composite phase. X-ray diffraction study has confirmed poly-crystalline growth of CZN films with fcc(331) and fcc(422) phases. High-resolution transmission electron microscope study reveals that CZN films are composed of ordered and crystalline ferromagnetic Co nano-clusters, which are embedded in the nano-composite matrix. Photoemission measurements show the change in the intensity near the Fermi level most likely due to defects and shift in the core-levels binding energy with nitrogen concentration. Raman spectroscopy data show an increase in the intensity of the Raman lines with nitrogen concentration upto 20%. However, the intensity is significantly lower for 30% sample. This indicates that less nitrogen or defect states are being substituted into the lattice above 20% and is consistent with the observed magnetic behavior. Our studies indicate that defects induced due to the incorporation of non-magnetic nitrogen content play a key role to enhance the magnetization

  16. Global ocean storage of anthropogenic carbon

    Directory of Open Access Journals (Sweden)

    S. Khatiwala

    2013-04-01

    Full Text Available The global ocean is a significant sink for anthropogenic carbon (Cant, absorbing roughly a third of human CO2 emitted over the industrial period. Robust estimates of the magnitude and variability of the storage and distribution of Cant in the ocean are therefore important for understanding the human impact on climate. In this synthesis we review observational and model-based estimates of the storage and transport of Cant in the ocean. We pay particular attention to the uncertainties and potential biases inherent in different inference schemes. On a global scale, three data-based estimates of the distribution and inventory of Cant are now available. While the inventories are found to agree within their uncertainty, there are considerable differences in the spatial distribution. We also present a review of the progress made in the application of inverse and data assimilation techniques which combine ocean interior estimates of Cant with numerical ocean circulation models. Such methods are especially useful for estimating the air–sea flux and interior transport of Cant, quantities that are otherwise difficult to observe directly. However, the results are found to be highly dependent on modeled circulation, with the spread due to different ocean models at least as large as that from the different observational methods used to estimate Cant. Our review also highlights the importance of repeat measurements of hydrographic and biogeochemical parameters to estimate the storage of Cant on decadal timescales in the presence of the variability in circulation that is neglected by other approaches. Data-based Cant estimates provide important constraints on forward ocean models, which exhibit both broad similarities and regional errors relative to the observational fields. A compilation of inventories of Cant gives us a "best" estimate of the global ocean inventory of anthropogenic carbon in 2010 of 155 ± 31 PgC (±20% uncertainty. This estimate includes a

  17. Global ocean storage of anthropogenic carbon

    Directory of Open Access Journals (Sweden)

    S. Khatiwala

    2012-07-01

    Full Text Available The global ocean is a significant sink for anthropogenic carbon (Cant, absorbing roughly a third of human CO2 emitted over the industrial period. Robust estimates of the magnitude and variability of the storage and distribution of Cant in the ocean are therefore important for understanding the human impact on climate. In this synthesis we review observational and model-based estimates of the storage and transport of Cant in the ocean. We pay particular attention to the uncertainties and potential biases inherent in different inference schemes. On a global scale, three data based estimates of the distribution and inventory of Cant are now available. While the inventories are found to agree within their uncertainty, there are considerable differences in the spatial distribution. We also present a review of the progress made in the application of inverse and data-assimilation techniques which combine ocean interior estimates of Cant with numerical ocean circulation models. Such methods are especially useful for estimating the air-sea flux and interior transport of Cant, quantities that are otherwise difficult to observe directly. However, the results are found to be highly dependent on modeled circulation, with the spread due to different ocean models at least as large as that from the different observational methods used to estimate Cant. Our review also highlights the importance of repeat measurements of hydrographic and biogeochemical parameters to estimate the storage of Cant on decadal timescales in the presence of the variability in circulation that is neglected by other approaches. Data-based Cant estimates provide important constraints on ocean forward models, which exhibit both broad similarities and regional errors relative to the observational fields. A compilation of inventories of Cant gives us a "best" estimate of

  18. Global ocean storage of anthropogenic carbon

    Science.gov (United States)

    Khatiwala, S.; Tanhua, T.; Mikaloff Fletcher, S.; Gerber, M.; Doney, S. C.; Graven, H. D.; Gruber, N.; McKinley, G. A.; Murata, A.; Ríos, A. F.; Sabine, C. L.

    2013-04-01

    The global ocean is a significant sink for anthropogenic carbon (Cant), absorbing roughly a third of human CO2 emitted over the industrial period. Robust estimates of the magnitude and variability of the storage and distribution of Cant in the ocean are therefore important for understanding the human impact on climate. In this synthesis we review observational and model-based estimates of the storage and transport of Cant in the ocean. We pay particular attention to the uncertainties and potential biases inherent in different inference schemes. On a global scale, three data-based estimates of the distribution and inventory of Cant are now available. While the inventories are found to agree within their uncertainty, there are considerable differences in the spatial distribution. We also present a review of the progress made in the application of inverse and data assimilation techniques which combine ocean interior estimates of Cant with numerical ocean circulation models. Such methods are especially useful for estimating the air-sea flux and interior transport of Cant, quantities that are otherwise difficult to observe directly. However, the results are found to be highly dependent on modeled circulation, with the spread due to different ocean models at least as large as that from the different observational methods used to estimate Cant. Our review also highlights the importance of repeat measurements of hydrographic and biogeochemical parameters to estimate the storage of Cant on decadal timescales in the presence of the variability in circulation that is neglected by other approaches. Data-based Cant estimates provide important constraints on forward ocean models, which exhibit both broad similarities and regional errors relative to the observational fields. A compilation of inventories of Cant gives us a "best" estimate of the global ocean inventory of anthropogenic carbon in 2010 of 155 ± 31 PgC (±20% uncertainty). This estimate includes a broad range of

  19. Anthropogenic impacts on Costa Rican bat parasitism are sex specific.

    Science.gov (United States)

    Frank, Hannah K; Mendenhall, Chase D; Judson, Seth D; Daily, Gretchen C; Hadly, Elizabeth A

    2016-07-01

    While anthropogenic impacts on parasitism of wildlife are receiving growing attention, whether these impacts vary in a sex-specific manner remains little explored. Differences between the sexes in the effect of parasites, linked to anthropogenic activity, could lead to uneven sex ratios and higher population endangerment. We sampled 1108 individual bats in 18 different sites across an agricultural mosaic landscape in southern Costa Rica to investigate the relationships between anthropogenic impacts (deforestation and reductions in host species richness) and bat fly ectoparasitism of 35 species of Neotropical bats. Although female and male bat assemblages were similar across the deforestation gradient, bat fly assemblages tracked their hosts closely only on female bats. We found that in female hosts, parasite abundance per bat decreased with increasing bat species richness, while in male hosts, parasite abundance increased. We hypothesize the differences in the parasite-disturbance relationship are due to differences in roosting behavior between the sexes. We report a sex-specific parasite-disturbance relationship and argue that sex differences in anthropogenic impacts on wildlife parasitism could impact long-term population health and survival. PMID:27547321

  20. Interactions of anthropogenic stress factors on marine phytoplankton

    OpenAIRE

    Häder, Donat-P.; Gao, Kunshan

    2015-01-01

    Phytoplankton are the main primary producers in aquatic ecosystems. Their biomass production and CO2 sequestration equals that of all terrestrial plants taken together. Phytoplankton productivity is controlled by a number of environmental factors, many of which currently undergo substantial changes due to anthropogenic global climate change. Most of these factors interact either additively or synergistically. Light availability is an absolute requirement for photosynthesis, but excessive visi...

  1. Numerical simulations examining the possible role of anthropogenic and volcanic emissions during the 1997 Indonesian fires.

    Science.gov (United States)

    Pfeffer, Melissa Anne; Langmann, Bärbel; Heil, Angelika; Graf, Hans-F

    2012-09-01

    The regional atmospheric chemistry and climate model REMOTE has been used to conduct numerical simulations of the atmosphere during the catastrophic Indonesian fires of 1997. These simulations represent one possible scenario of the event, utilizing the RETRO wildland fire emission database. Emissions from the fires dominate the atmospheric concentrations of O(3), CO, NO(2), and SO(2) creating many possible exceedances of the Indonesian air quality standards. The scenario described here suggests that urban anthropogenic emissions contributed to the poor air quality due primarily to the fires. The urban air pollution may have increased the total number of people exposed to exceedances of the O(3) 1-h standard by 17%. Secondary O(3) from anthropogenic emissions enhanced the conversion of SO(2) released by the fires to [Formula: see text], demonstrating that the urban pollution actively altered the atmospheric behavior and lifetime of the fire emissions. Under the conditions present during the fires, volcanic SO(2) emissions had a negligible influence on surface pollution. PMID:22942920

  2. Do Anthropogenic Dark Earths Occur in the Interior of Borneo? Some Initial Observations from East Kalimantan

    OpenAIRE

    D. Sheil; Basuki, I.; German, L.; Kuyper, T. W.; Limberg, G.; Puri, R. K.; Sellato, B.; Noordwijk, van, M.

    2012-01-01

    Anthropogenic soils of the Amazon Basin (Terra Preta, Terra Mulata) reveal that pre-Colombian peoples made lasting improvements in the agricultural potential of nutrient-poor soils. Some have argued that applying similar techniques could improve agriculture over much of the humid tropics, enhancing local livelihoods and food security, while also sequestering large quantities of carbon to mitigate climate change. Here, we present preliminary evidence for Anthropogenic Dark Earths (ADEs) in tro...

  3. Anthropogenic Triggering of Large Earthquakes

    Science.gov (United States)

    Mulargia, Francesco; Bizzarri, Andrea

    2014-08-01

    The physical mechanism of the anthropogenic triggering of large earthquakes on active faults is studied on the basis of experimental phenomenology, i.e., that earthquakes occur on active tectonic faults, that crustal stress values are those measured in situ and, on active faults, comply to the values of the stress drop measured for real earthquakes, that the static friction coefficients are those inferred on faults, and that the effective triggering stresses are those inferred for real earthquakes. Deriving the conditions for earthquake nucleation as a time-dependent solution of the Tresca-Von Mises criterion applied in the framework of poroelasticity yields that active faults can be triggered by fluid overpressures < 0.1 MPa. Comparing this with the deviatoric stresses at the depth of crustal hypocenters, which are of the order of 1-10 MPa, we find that injecting in the subsoil fluids at the pressures typical of oil and gas production and storage may trigger destructive earthquakes on active faults at a few tens of kilometers. Fluid pressure propagates as slow stress waves along geometric paths operating in a drained condition and can advance the natural occurrence of earthquakes by a substantial amount of time. Furthermore, it is illusory to control earthquake triggering by close monitoring of minor ``foreshocks'', since the induction may occur with a delay up to several years.

  4. Forging the anthropogenic iron cycle.

    Science.gov (United States)

    Wang, Tao; Müller, Daniel B; Graedel, T E

    2007-07-15

    Metallurgical iron cycles are characterized for four anthropogenic life stages: production, fabrication and manufacturing, use, and waste management and recycling. This analysis is conducted for year 2000 and at three spatial levels: 68 countries and territories, nine world regions, and the planet. Findings include the following: (1) contemporary iron cycles are basically open and substantially dependent on environmental sources and sinks; (2) Asia leads the world regions in iron production and use; Oceania, Latin America and the Caribbean, Africa, and the Commonwealth of Independent States present a highly production-biased iron cycle; (3) purchased scrap contributes a quarter of the global iron and steel production; (4) iron exiting use is three times less than that entering use; (5) about 45% of global iron entering use is devoted to construction, 24% is devoted to transport equipment, and 20% goes to industrial machinery; (6) with respect to international trade of iron ore, iron and steel products, and scrap, 54 out of the 68 countries are net iron importers, while only 14 are net exporters; (7) global iron discharges in tailings, slag, and landfill approximate one-third of the iron mined. Overall, these results provide a foundation for studies of iron-related resource policy, industrial development, and waste and environmental management. PMID:17711233

  5. Anthropogenic influence on multidecadal changes in reconstructed global evapotranspiration

    Science.gov (United States)

    Douville, H.; Ribes, A.; Decharme, B.; Alkama, R.; Sheffield, J.

    2013-01-01

    Global warming is expected to intensify the global hydrological cycle, with an increase of both evapotranspiration (EVT) and precipitation. Yet, the magnitude and spatial distribution of this global and annual mean response remains highly uncertain. Better constraining land EVT in twenty-first-century climate scenarios is critical for predicting changes in surface climate, including heatwaves and droughts, evaluating impacts on ecosystems and water resources, and designing adaptation policies. Continental scale EVT changes may already be underway, but have never been attributed to anthropogenic emissions of greenhouse gases and sulphate aerosols. Here we provide global gridded estimates of annual EVT and demonstrate that the latitudinal and decadal differentiation of recent EVT variations cannot be understood without invoking the anthropogenic radiative forcings. In the mid-latitudes, the emerging picture of enhanced EVT confirms the end of the dimming decades and highlights the possible threat posed by increasing drought frequency to managing water resources and achieving food security in a changing climate.

  6. Anthropogenic substances and products containing natural radionuclides. Radiation exposure analysis

    International Nuclear Information System (INIS)

    The anthropogenic component of radiation exposure stems from man's activities. It can be induced both by artificial and natural radionuclides. Radiation exposure due to natural radionuclides can be attributed to anthropogenic materials and products: raw materials, wastes, consumer goods, aricles of daily use. The potential radiation exposure induced by artificial radionuclides is subject to monitoring and rigid regulatory provisions at international level. Recently, exposure from natural radionuclides has become an aspect attracting increasing attention, one major reason being the disturbance detected in the ''normal'' natural background radiation, which is a result of man's activities (modified natural radiation exposure). The lecture briefly reviews the existing laws and regulations and a list of the raw materials, wastes, consumer goods and articles of daily use which contain natural radionuclides. The concluding part discusses results of radiation exposure assessments for a variety of relevant situations and cases. (orig./DG)

  7. Enhanced intersystem crossing due to long-range exchange interaction in copper(II) porphyrin-free base porphyrin dimers: HOMO and spacer dependence

    International Nuclear Information System (INIS)

    Highlights: • We found a parallel relationship between the two correlation lines of ln Δkisc vs. number of bonds. • Effects of HOMO of the terminal chromophore appear as the intercept of the correlation lines. • Difference of HOMO of the terminal porphyrin does not affect the interaction within the bridge part. • An expression involving both HOMO and spacer dependence for EISC rate was derived. - Abstract: Photodynamics induced by long-range exchange interaction was studied in two series of copper(II) porphyrin – free base porphyrin dimers linked via an aromatic spacer: one has a2u orbital as HOMO in the porphyrin π-system and the other has a1u orbital. Dependence on the HOMO as well as that on the spacer is presented for enhanced intersystem crossing (EISC) occurring in the free base half due to long-range coupling with the copper unpaired electron. Semilogarithmic plots of EISC rates vs. number of bonds show a linear correlation in each series of dimers. It was found that the two correlation lines show the same slope but different intercepts. This clearly indicates that electronic communication within the linkage does not depend on the terminal chromophore, while the terminal π-system affects the magnitude of EISC rates. Separately, a general expression for EISC rate, involving coupling between the terminal and linkage, was derived theoretically

  8. Natural and anthropogenic radionuclides in the environment

    International Nuclear Information System (INIS)

    A survey is given on the actual knowledge about occurence and environmental relevancy of the most important radionuclides from natural and anthropogenic origin. The contribution of AGF installation is emphasized. (orig.)

  9. Detecting anthropogenic footprints in sea level rise

    OpenAIRE

    Dangendorf, Sönke; Marcos, Marta; Müller, Alfred; Zorita, Eduardo; Riva, Riccardo; Berk, Kevin; Jensen, Jürgen

    2015-01-01

    While there is scientific consensus that global and local mean sea level (GMSL and LMSL) has risen since the late nineteenth century, the relative contribution of natural and anthropogenic forcing remains unclear. Here we provide a probabilistic upper range of long-term persistent natural GMSL/LMSL variability (P=0.99), which in turn, determines the minimum/maximum anthropogenic contribution since 1900. To account for different spectral characteristics of various contributing processes, we se...

  10. Ursus arctos : ethology and anthropogenic disturbances

    OpenAIRE

    Duran Tapia, Joana

    2015-01-01

    Brown bear (Ursus arctos) is a typically solitary mammal. Because of this and its elusiveness, its ethology is difficult to study and is not still completely understood. Brown bear’s behavior is highly influenced by some of its reproductive characteristics and, increasingly, by anthropogenic disturbance. Thus, it is important to analyse the impact of anthropogenic disturbance on brown bear’s ethology and to develop management strategies to minimize negative impacts.

  11. Blue Whales Respond to Anthropogenic Noise

    OpenAIRE

    Mariana L Melcón; Amanda J Cummins; Kerosky, Sara M; Lauren K Roche; Wiggins, Sean M.; John A. Hildebrand

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to...

  12. Late Holocene climate: Natural or anthropogenic?

    Science.gov (United States)

    Ruddiman, W. F.; Fuller, D. Q.; Kutzbach, J. E.; Tzedakis, P. C.; Kaplan, J. O.; Ellis, E. C.; Vavrus, S. J.; Roberts, C. N.; Fyfe, R.; He, F.; Lemmen, C.; Woodbridge, J.

    2016-03-01

    For more than a decade, scientists have argued about the warmth of the current interglaciation. Was the warmth of the preindustrial late Holocene natural in origin, the result of orbital changes that had not yet driven the system into a new glacial state? Or was it in considerable degree the result of humans intervening in the climate system through greenhouse gas emissions from early agriculture? Here we summarize new evidence that moves this debate forward by testing both hypotheses. By comparing late Holocene responses to those that occurred during previous interglaciations (in section 2), we assess whether the late Holocene responses look different (and thus anthropogenic) or similar (and thus natural). This comparison reveals anomalous (anthropogenic) signals. In section 3, we review paleoecological and archaeological syntheses that provide ground truth evidence on early anthropogenic releases of greenhouse gases. The available data document large early anthropogenic emissions consistent with the anthropogenic ice core anomalies, but more information is needed to constrain their size. A final section compares natural and anthropogenic interpretations of the δ13C trend in ice core CO2.

  13. Implications of anthropogenic acidification on forest soil processes in Sweden

    International Nuclear Information System (INIS)

    By anthropogenic acidification the soil forming process, podzolisation, will be perturbed. The organic acids in soil solution will form complexes with aluminium to a less degree and inorganic aluminium will be leached from the illuvial horizon. The soil acidification has not resulted in declined coniferous forest growth, which might be explained by mycorrhizal activity promoting nutrient uptake direct from minerals. Liming and wood ash applications on forest soil might enhance CO2 evolution, increase DOC concentrations and might also initially decrease pH and increase Al concentrations in soil solution

  14. A passive measurement technique for characterisation of high-risk houses in Japan due to enhanced levels of indoor radon and thoron concentrations

    International Nuclear Information System (INIS)

    A passive dosemeter has been developed which can measure radon and thoron concentrations separately. The dosemeter has a structure of two hemispheric chambers, one 120 mmφ and the other 75 mmφ, being combined into a saucer-like shape. Environmental air diffuses into the first chamber of 120 mmφ from the inlets covered with glass fibre filters, from which it passes into the second chamber of 75 mmφ. Each chamber contains a disc of polycarbonate film of 50 mm diameter with a 300 μm thickness as an α track detector. A detector film in the first chamber of 120 mmφ, is subjected to chemical etching (8N KOH(C2H5OH 20%vol.) at 30oC) for 3 h and electrochemical etching (AC800V, 2kHz) for 3 h in order to develop α tracks with high incident energy (2.5 - 4.0 MeV) dominantly originating from thoron and its daughters. Another detector film in the second hemispheric chamber of 75 mmφ, is subjected to chemical etching for 30 min and electrochemical etching for 3 h to develop α tracks with low incident energy (0.8 - 2.7 MeV) dominantly originating from radon and its progeny. In addition, a pinhole air inlet between the 120 mmφ and 75 mmφ hemispheric chambers causes the diffusion barrier which interrupts the thoron gas entering the 75 mmφ hemispheric chamber (only 0.22% of thoron gas diffuses into the chamber) in order to enhance the discrimination ratio. Results of an interim survey using the new dosemeter suggest that certain types of Japanese wooden houses have a high risk due to thoron and its daughters rather than radon and its progeny. (author)

  15. Caribbean coral growth influenced by anthropogenic aerosol emissions

    Science.gov (United States)

    Kwiatkowski, Lester; Cox, Peter M.; Economou, Theo; Halloran, Paul R.; Mumby, Peter J.; Booth, Ben B. B.; Carilli, Jessica; Guzman, Hector M.

    2013-05-01

    Coral growth rates are highly dependent on environmental variables such as sea surface temperature and solar irradiance. Multi-decadal variability in coral growth rates has been documented throughout the Caribbean over the past 150-200 years, and linked to variations in Atlantic sea surface temperatures. Multi-decadal variability in sea surface temperatures in the North Atlantic, in turn, has been linked to volcanic and anthropogenic aerosol forcing. Here, we examine the drivers of changes in coral growth rates in the western Caribbean between 1880 and 2000, using previously published coral growth chronologies from two sites in the region, and a numerical model. Changes in coral growth rates over this period coincided with variations in sea surface temperature and incoming short-wave radiation. Our model simulations show that variations in the concentration of anthropogenic aerosols caused variations in sea surface temperature and incoming radiation in the second half of the twentieth century. Before this, variations in volcanic aerosols may have played a more important role. With the exception of extreme mass bleaching events, we suggest that neither climate change from greenhouse-gas emissions nor ocean acidification is necessarily the driver of multi-decadal variations in growth rates at some Caribbean locations. Rather, the cause may be regional climate change due to volcanic and anthropogenic aerosol emissions.

  16. Satellite constraint for emissions of nitrogen oxides from anthropogenic, lightning and soil sources over East China on a high-resolution grid

    Directory of Open Access Journals (Sweden)

    J.-T. Lin

    2012-03-01

    Full Text Available Vertical column densities (VCDs of tropospheric nitrogen dioxide (NO2 retrieved from space provide valuable information to estimate emissions of nitrogen oxides (NOx inversely. Accurate emission attribution to individual sources, important both for understanding the global biogeochemical cycling of nitrogen and for emission control, remains difficult. This study presents a regression-based multi-step inversion approach to estimate emissions of NOx from anthropogenic, lightning and soil sources individually for 2006 over East China on a 0.25° long × 0.25° lat grid, employing the DOMINO product version 2 retrieved from the Ozone Monitoring Instrument. The inversion is done gridbox by gridbox to derive the respective emissions, taking advantage of differences in seasonality between anthropogenic and natural sources. Lightning and soil emissions are combined together for any given gridbox due to their similar seasonality; and their different spatial distributions are used implicitly for source separation to some extent. The nested GEOS-Chem model for East Asia is used to simulate the seasonal variations of different emission sources and impacts on VCDs of NO2 for the inversion purpose. Sensitivity tests are conducted to evaluate key assumptions embedded in the inversion process. The inverse estimate suggests annual budgets of about 7.1 TgN (±39%, 0.21 TgN (±61%, and 0.38 TgN (±65% for the a posteriori anthropogenic, lightning and soil emissions, respectively, about 18–23% higher than the respective a priori values. The enhancements in anthropogenic emissions are largest in cities and areas with extensive use of coal, particularly in the north in winter, as evident on the high-resolution grid. Derived soil emissions are consistent with recent bottom-up estimates. They are less than 6% of anthropogenic emissions annually, increasing to about 13% for July. Derived lightning emissions are about 3% of

  17. Engineering paradigms and anthropogenic global change

    Science.gov (United States)

    Bohle, Martin

    2016-04-01

    This essay discusses 'paradigms' as means to conceive anthropogenic global change. Humankind alters earth-systems because of the number of people, the patterns of consumption of resources, and the alterations of environments. This process of anthropogenic global change is a composite consisting of societal (in the 'noosphere') and natural (in the 'bio-geosphere') features. Engineering intercedes these features; e.g. observing stratospheric ozone depletion has led to understanding it as a collateral artefact of a particular set of engineering choices. Beyond any specific use-case, engineering works have a common function; e.g. civil-engineering intersects economic activity and geosphere. People conceive their actions in the noosphere including giving purpose to their engineering. The 'noosphere' is the ensemble of social, cultural or political concepts ('shared subjective mental insights') of people. Among people's concepts are the paradigms how to shape environments, production systems and consumption patterns given their societal preferences. In that context, engineering is a means to implement a given development path. Four paradigms currently are distinguishable how to make anthropogenic global change happening. Among the 'engineering paradigms' for anthropogenic global change, 'adaptation' is a paradigm for a business-as-usual scenario and steady development paths of societies. Applying this paradigm implies to forecast the change to come, to appropriately design engineering works, and to maintain as far as possible the current production and consumption patterns. An alternative would be to adjust incrementally development paths of societies, namely to 'dovetail' anthropogenic and natural fluxes of matter and energy. To apply that paradigm research has to identify 'natural boundaries', how to modify production and consumption patterns, and how to tackle process in the noosphere to render alterations of common development paths acceptable. A further alternative

  18. Due diligence

    International Nuclear Information System (INIS)

    The Occupational Health and Safety (OHS) Act requires that every employer shall ensure the health and safety of workers in the workplace. Issues regarding the practices at workplaces and how they should reflect the standards of due diligence were discussed. Due diligence was described as being the need for employers to identify hazards in the workplace and to take active steps to prevent workers from potentially dangerous incidents. The paper discussed various aspects of due diligence including policy, training, procedures, measurement and enforcement. The consequences of contravening the OHS Act were also described

  19. The Oceanic Sink for Anthropogenic CO2

    Energy Technology Data Exchange (ETDEWEB)

    Sabine, Chris [NOAA, Seattle, WA; Feely, R. A. [NOAA Pacific Marine Environmental Laboratory; Gruber, N. [ETH Zurich, Switzerland; Key, Robert [Princeton University; Lee, K. [Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea; Bullister, J.L. [NOAA Pacific Marine Environmental Laboratory; Wanninkhof, R. [Atlantic Oceanographic & Meteorological Laboratory, NOAA; Wong, C. S. [Institute of Ocean Sciences, Climate Chemistry Laboratory, Sidney, BC Canada; Wallace, D.W.R. [IFM-GEOMAR, Leibniz Institute for Marine Sciences, Chemical Oceanography, Kiel, Germany; Tilbrook, B. [CSIRO Marine and Atmospheric Research; Millero, F. J. [University of Miami; Peng, T.-H. [Atlantic Oceanographic & Meteorological Laboratory, NOAA; Kozyr, Alexander [ORNL; Ono, Tsueno [Frontier Research System for Global Change/Institute for Global Change Research, Japan; Rios, Aida F. [Instituto de Investigaciones Marinas, Consejo Superior de Investigationes Cientificas, Spain

    2004-01-01

    Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO2) sink for the period from 1800 to 1994 of 118 19 petagrams of carbon. The oceanic sink accounts for ~48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO2 to the atmosphere of about 39 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO2 emissions stored in the ocean appears to be about one-third of the long-term potential.

  20. Quantification of continual anthropogenic pollutants released in swimming pools.

    Science.gov (United States)

    Keuten, M G A; Peters, M C F M; Daanen, H A M; de Kreuk, M K; Rietveld, L C; van Dijk, J C

    2014-04-15

    Disinfection in swimming pools is often performed by chlorination, However, anthropogenic pollutants from swimmers will react with chlorine and form disinfection by-products (DBPs). DBPs are unwanted from a health point of view, because some are irritating, while others might be carcinogenic. The reduction of anthropogenic pollutants will lead to a reduction in DBPs. This paper investigates the continual release of anthropogenic pollutants by means of controlled sweat experiments in a pool tank during laboratory time-series experiments (LTS experiments) and also during on-site experiments (OS experiments) in a swimming pool. The sweat released during the OS and LTS experiments was very similar. The sweat rate found was 0.1-0.2 L/m(2)/h at water temperatures below 29 °C and increased linearly with increasing water temperatures to 0.8 L/m(2)/h at 35 °C. The continual anthropogenic pollutant release (CAPR) not only consisted of sweat, particles (mainly skin fragments and hair) and micro-organisms, but also sebum (skin lipids) has to be considered. The release of most components can be explained by the composition of sweat. The average release during 30 min of exercise is 250 mg/bather non-purgeable organic carbon (NPOC), 77.3 mg/bather total nitrogen (TN), 37.1 mg/bather urea and 10.1 mg/bather ammonium. The release of NPOC cannot be explained by the composition of sweat and is most probably a result of sebum release. The average release of other components was 1.31 × 10(9) # particles/bather (2-50 μm), 5.2 μg/bather intracellular adenosine triphosphate (cATP) and 9.3 × 10(6) intact cell count/bather (iCC). The pool water temperature was the main parameter to restrain the CAPR. This study showed that a significant amount of the total anthropogenic pollutants release is due to unhygienic behaviour of bathers. PMID:24530546

  1. CLASSIFICATION OF ANTHROPOGENIC TRANSFORMATIONS SOILS URBOECOSYSTEMS OF DNEPROPETROVSK

    Directory of Open Access Journals (Sweden)

    YAKOVYSHYNA T.F.

    2015-12-01

    Full Text Available Raising of problem. The functioning of the city, as artificially created system of the result of the anthropogenic activity, promotes degradation and, sometimes, destruction of the environment, with change it to the technogenic replacement. First of all suffers the soil, as a basic component of any ecosystem, where the circulation of materials close, because it is a powerful biogeochemical barrier to their migration, able to deposit toxicants a long time through its protective functions. The leading role of the formation of the urban soil plays an anthropogenic factor, which is able to influence directly – the destruction of the soil profile due to construction activity and indirectly – with aerogenic or hydrogenous pollution xenobiotics contained in the emissions and discharges of the industrial enterprises; and it is determined by the type of economic use and history of area developing. The variability of using the urban soil is reflected in the soil profile and contributed to the creation of the organic-mineral layer by the mixing, mound, burial and (or contamination of the different substances on the surface. Therefore, classification of the urban soils by the anthropogenic destruction degree of the soil profile is very important scientific and practical task for the urban ecology to the achievement standards of the ecological safety of the modern city, because the restoring of their protective functions is impossible without knowledge of the morphological structure. Purpose. Classify the anthropogenical soils of city Dnipropetrovsk disturbed by the construction activities by the determining of the morphological characteristics of the soil profile structure with separation of the anthropogenic and technogenic surface formations compared to the zonal soil – ordinery chernozem. Conclusion. Within urboecosystem city Dnipropetrovsk long-term human impact to the zonal soil – chernozem led to its transformation into urbanozem witch

  2. Do Anthropogenic Dark Earths Occur in the Interior of Borneo? Some Initial Observations from East Kalimantan

    NARCIS (Netherlands)

    Sheil, D.; Basuki, I.; German, L.; Kuyper, T.W.; Limberg, G.; Puri, R.K.; Sellato, B.; Noordwijk, van M.

    2012-01-01

    Anthropogenic soils of the Amazon Basin (Terra Preta, Terra Mulata) reveal that pre-Colombian peoples made lasting improvements in the agricultural potential of nutrient-poor soils. Some have argued that applying similar techniques could improve agriculture over much of the humid tropics, enhancing

  3. Anthropogenic sinkholes in the town of Naples

    Science.gov (United States)

    Vennari, Carmela; Parise, Mario

    2016-04-01

    The importance of sinkhole as a natural hazard is often underrated when compared with landslides, floods, volcanic eruptions and earthquakes in Italy. Sinkholes are rarely included in risk analysis despite their frequent occurrence in several parts of Italy, especially in karst lands or in those sectors of the country where artificial cavities have been realized underground by man for different purposes. Among the most affected Italian regions, Campania (southern Italy) stands out for several reasons, with particular regard to the town of Naples, highly affected by anthropogenic sinkholes. These latter have caused serious damage to society, and above all to people in terms of deaths, missing persons, and injured people, due to the high urbanization of the city, developed above a complex and extensive network of cavities, excavated during the 2000 years of history of the town. Among the different typologies of artificial cavities, it is worth mentioning the high number of ancient quarry used to extract the building materials for the town construction. The Institute of Research for the Hydrological Protection (IRPI) of the National Research Council of Italy (CNR) has been working in the last years at populating a specific chronological database on sinkholes in the whole Italian country. On the base of the collected data, Naples appears to have been affected by not less than 250 events from the beginning of the century to nowadays. The IRPI database includes only sinkholes for which a temporal reference on their time of occurrence is known. Particular attention was given on this information, since the catalogue idea is to make a starting point for a complete sinkhole hazard analysis. At this aim, knowledge of the time of occurrence is mandatory. Day, month and year of the event are known for about 70% of sinkholes that took place in Naples, but the hour of occurrence is known for just 6% of the data. Information about site of occurrence are, on the other hand, highly

  4. The influence of vegetation dynamics on anthropogenic climate change

    Directory of Open Access Journals (Sweden)

    U. Port

    2012-07-01

    Full Text Available In this study, vegetation-climate and vegetation-carbon cycle interactions during anthropogenic climate change are assessed by using the Earth System Model MPI ESM including a module for vegetation dynamics. We assume anthropogenic CO2 emissions according to the RCP 8.5 scenario in the period from 1850 to 2120 and shut them down afterwards to evaluate the equilibrium response of the Earth System by 2300.

    Our results suggest that vegetation dynamics have a considerable influence on the changing global and regional climate. In the simulations, global mean tree cover extends by 2300 due to increased atmospheric CO2 concentration and global warming. Thus, land carbon uptake is higher and atmospheric CO2 concentration is lower by about 40 ppm when considering dynamic vegetation compared to a static pre-industrial vegetation cover. The reduced atmospheric CO2 concentration is equivalent to a lower global mean temperature. Moreover, biogeophysical effects of vegetation cover shifts influence the climate on a regional scale. Expanded tree cover in the northern high latitudes results in a reduced albedo and additional warming. In the Amazon region, declined tree cover causes a higher temperature as evapotranspiration is reduced. In total, we find that vegetation dynamics have a slight attenuating effect on global climate change as the global climate cools by 0.22 K in 2300 due to natural vegetation cover shifts.

  5. Anthropogenic disturbances jeopardize biodiversity conservation within tropical rainforest reserves.

    Science.gov (United States)

    Martínez-Ramos, Miguel; Ortiz-Rodríguez, Iván A; Piñero, Daniel; Dirzo, Rodolfo; Sarukhán, José

    2016-05-10

    Anthropogenic disturbances affecting tropical forest reserves have been documented, but their ecological long-term cumulative effects are poorly understood. Habitat fragmentation and defaunation are two major anthropogenic threats to the integrity of tropical reserves. Based on a long-term (four decades) study, we document how these disturbances synergistically disrupt ecological processes and imperil biodiversity conservation and ecosystem functioning at Los Tuxtlas, the northernmost tropical rainforest reserve in the Americas. Deforestation around this reserve has reduced the reserve to a medium-sized fragment (640 ha), leading to an increased frequency of canopy-gap formation. In addition, hunting and habitat loss have caused the decline or local extinction of medium and large herbivores. Combining empirical, experimental, and modeling approaches, we support the hypothesis that such disturbances produced a demographic explosion of the long-lived (≈120 y old, maximum height of 7 m) understory palm Astrocaryum mexicanum, whose population has increased from 1,243-4,058 adult individuals per hectare in only 39 y (annual growth rate of ca 3%). Faster gap formation increased understory light availability, enhancing seed production and the growth of immature palms, whereas release from mammalian herbivory and trampling increased survival of seedlings and juveniles. In turn, the palm's demographic explosion was followed by a reduction of tree species diversity, changing forest composition, altering the relative contribution of trees to forest biomass, and disrupting litterfall dynamics. We highlight how indirect anthropogenic disturbances (e.g., palm proliferation) on otherwise protected areas threaten tropical conservation, a phenomenon that is currently eroding the planet's richest repositories of biodiversity. PMID:27071122

  6. Do anthropogenic or coastal aerosol sources impact on a clean marine aerosol signature at Mace Head?

    Science.gov (United States)

    O'Dowd, C.; Ceburnis, D.; Ovadnevaite, J.; Rinaldi, M.; Facchini, M. C.

    2013-03-01

    Atmospheric aerosols have been sampled and characterised at the Mace Head North East (N.E.) Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station to that of aerosol over the open ocean. Two recurring criticisms relate to the lack of representativeness due to enhanced coastal sources, thereby leading to artificially high values to aerosol parameters, and to the influence of long-range transport of anthropogenic aerosol and its potential dominance over, or drowning-out of, a natural marine aerosol signal. Here we review the results of previous experimental studies into marine aerosols over the N.E. Atlantic and at Mace Head with the aim of evaluating their representativeness relative to that of an open ocean aerosol with negligible anthropogenic influence. Particular focus is given to organic matter (OM) aerosol. In summary, no correlation was found between OM and black carbon (BC) either at BC levels of 0-15 or 15-50 ng m-3, suggesting that OM concentrations up to peak values of 3.8 μg m-3 are predominantly natural in origin. Sophisticated carbon isotope analysis and aerosol mass spectral finger printing corroborate the natural source of OM with 80% biogenic source apportionment being observed for general clean air conditions, rising to 98% during specific primary marine organic plumes when peak concentrations >3 μg m-3 are observed. A range of other experiments are discussed which corroborate the dominance of a marine signal under Mace Head clean air criteria along. Further, analysis of a series of experiments conducted at Mace Head conclude that negligible coastal, surf zone, or tidal effects are discernible in the submicron size range for sampling heights of 7 m and above. The Mace Head clean air criteria ensures anthropogenic and

  7. Do anthropogenic or coastal aerosol sources impact on a clean marine aerosol signature at Mace Head?

    Directory of Open Access Journals (Sweden)

    C. O'Dowd

    2013-03-01

    Full Text Available Atmospheric aerosols have been sampled and characterised at the Mace Head North East (N.E. Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station to that of aerosol over the open ocean. Two recurring criticisms relate to the lack of representativeness due to enhanced coastal sources, thereby leading to artificially high values to aerosol parameters, and to the influence of long-range transport of anthropogenic aerosol and its potential dominance over, or drowning-out of, a natural marine aerosol signal. Here we review the results of previous experimental studies into marine aerosols over the N.E. Atlantic and at Mace Head with the aim of evaluating their representativeness relative to that of an open ocean aerosol with negligible anthropogenic influence. Particular focus is given to organic matter (OM aerosol. In summary, no correlation was found between OM and black carbon (BC either at BC levels of 0–15 or 15–50 ng m−3, suggesting that OM concentrations up to peak values of 3.8 μg m−3 are predominantly natural in origin. Sophisticated carbon isotope analysis and aerosol mass spectral finger printing corroborate the natural source of OM with 80% biogenic source apportionment being observed for general clean air conditions, rising to 98% during specific primary marine organic plumes when peak concentrations >3 μg m−3 are observed. A range of other experiments are discussed which corroborate the dominance of a marine signal under Mace Head clean air criteria along. Further, analysis of a series of experiments conducted at Mace Head conclude that negligible coastal, surf zone, or tidal effects are discernible in the submicron size range for sampling heights of 7 m and above. The Mace Head clean air criteria

  8. Research and Development in the Anthropogenic Cryosphere

    Science.gov (United States)

    de Jong, C.; Luthe, T.; Hohenwallne, D.

    2009-04-01

    fauna, modification of local hydrological cycle and modification of local climate and atmospheric pollution. Research in mountains should balance the needs of scientists and stakeholders alike, but this requires re-orientation of mountain research into multi-disciplinary projects next to basic science. Unlike the polar regions (with exceptions like Longyearbyen, Spitzbergen), seasonal population pressure in mountains is intense, causing local problems such as water scarcity. Research in these areas therefore requires close collaboration with stakeholders. Large-scale events such as Winter Olympics that have benefited from the classical mountain cryosphere in the past are now increasingly becoming internationally competitive and independent of the natural cryospheric conditions. New ski areas are developed world-wide in zones that do not offer natural climatological conditions for maintaining ski runs. Sub-zero temperatures are used as a basis for snow-making even in those regions that do not benefit from sufficient natural snow-fall. Large-scale landscape modification results in motorway like ski runs, large snow water reservoirs and extensive housing projects on vulnerable slopes. Due to steep and remote topography, transport is often dominated by cars and increases CO2 emissions intensively at local hot spots. In future, mountain slopes that have been heavily modified for winter tourism, may rapidly become neglected zones due to rapid snowline retreat. As the summer season extends, the modifications to the cryosphere will become more and more evident. Even with positive temperatures and snow-free ground, the vegetation season will not be extensive enough to enable rapid recovery, especially at altitudes above 2000 m a.s.l and north-facing aspects. Several decades of anthropogenic modification may require several centuries of recovery to provide new economical benefits.

  9. Oxidation of elemental mercury in anthropogenic pollution plumes and in Pacific marine air masses observed at the Mt. Bachelor Observatory

    Science.gov (United States)

    Ambrose, J. L.; Timonen, H. J.; Jaffe, D. A.

    2012-12-01

    The atmospheric chemistry of mercury (Hg) is poorly understood, especially the oxidation of gaseous elemental mercury (GEM) and production of gaseous oxidized mercury (GOM). Since 2004 we have measured speciated Hg and other tracers at the Mt. Bachelor Observatory (MBO) in central Oregon, USA. We see frequent enhancements in GEM due to long range transport of pollution from Asia. Occasionally we also see large enhancements in GOM. Previously we have shown (Swartzendruber et al., 2006; Lyman and Jaffe, 2011) that the upper troposphere is a significant source of GOM to the troposphere. Here we describe two previously unidentified sources of GOM in the Pacific Northwest lower free troposphere: (1) oxidation of GEM in Asian pollution plumes during trans-Pacific long-range transport; (2) oxidation of GEM in marine air masses originating over the extra-tropical Eastern Pacific. In both cases, GOM was strongly anti-correlated with GEM, indicating in-situ oxidation of GEM rather than transport of GOM that was either emitted from anthropogenic sources in Asia or emitted in the Pacific marine boundary layer. During the Asian pollution episodes GOM was correlated with pollution tracers (CO, O3, and submicron particle scattering), but the GOM enhancements (i.e., the ratio GOM/GEM) reached peak values, up to ~0.20, which are significantly larger than emission ratios, typically <0.05, as measured in Asian anthropogenic pollution. Conversely, during the marine episodes GOM was anti-correlated with CO and O3. The GOM concentrations during the marine episodes reached peak values up to 700 pg/m3, with GOM/GEM ratios of up to ~1. These are among the highest GOM concentrations seen in the entire MBO data record and comparable to the highest GOM values reported anywhere in the world outside of heavily polluted Hg mining sites. Oxidation of GEM in anthropogenic plumes and in marine air may be important loss processes for GEM globally. These oxidation processes will significantly enhance

  10. The Anthropogenic/Lightning Effects Around Houston: The Houston Environmental Aerosol Thunderstorm (HEAT) Project - 2005

    Science.gov (United States)

    Orville, R. E.

    2004-12-01

    A major field program will occur in summer 2005 to determine the sources and causes for the enhanced cloud-to-ground lightning over Houston, Texas. This program will be in association with simultaneous experiments supported by the Environmental Protection Agency (EPA) and the Texas Commission on Environmental Quality (TCEQ), formally the Texas Natural Resource Conservation Commission (TNRCC). Recent studies covering the period 1989-2002 document a 60 percent increase of cloud-to-ground lightning in the Houston area as compared to surrounding background values, which is second in flash density only to the Tampa Bay, Florida area. We suggest that the elevated flash densities could result from several factors, including 1) the convergence due to the urban heat island effect and complex sea breeze (thermal hypothesis), and 2) the increasing levels of air pollution from anthropogenic sources producing numerous small cloud droplets and thereby suppressing mean droplet size (aerosol hypothesis). The latter effect would enable more cloud water to reach the mixed phase region where it is involved in the formation of precipitation and the separation of electric charge, leading to an enhancement of lightning. The primary goals of HEAT are to examine the effects of (1) pollution, (2) the urban heat island, and (3) the complex coastline on storms and lightning characteristics in the Houston area. The transport of air pollutants by Houston thunderstorms will be investigated. In particular, the relative amounts of lightning-produced and convectively transported NOx into the upper troposphere will be determined, and a comparison of the different NOx sources in the urban area of Houston will be developed. The HEAT project is based on the observation that there is an enhancement in cloud-to-ground (CG) lightning. Total lightning (intracloud (IC) and CG) will be measured using a lightning mapping system (LDAR II) to observe if there is an enhancement in intracloud lightning as well.

  11. Numerical Study of the Eff ect of Anthropogenic Aerosols on Spring Persistent Rain over Eastern China

    Institute of Scientific and Technical Information of China (English)

    DENG Jiechun; XU Haiming; MA Hongyun; JIANG Zhihong

    2014-01-01

    The eff ect of anthropogenic aerosols on the spring persistent rain (SPR) over eastern China is investigated by using a high-resolution Community Atmosphere Model version 5.1 (CAM5.1). The results show that the SPR starts later due to anthropogenic aerosols, with a shortened duration and reduced rainfall amount. A reduction in air temperature over the low latitudes in East Asia is linked to anthropogenic aerosols;so is a weakened southwesterly on the north side of the subtropical high. Meanwhile, air temperature increases signifi cantly over the high latitudes. This north-south asymmetrical thermal eff ect acts to reduce the meridional temperature gradient, weakening the upper-level westerly jet over East Asia and the vertical motion over southeastern China. As a result, the SPR is reduced and has a much shorter duration. The indirect eff ect of anthropogenic aerosols also plays an important role in changing the SPR. Cloud droplet number concentration increases due to anthropogenic aerosols acting as cloud condensation nuclei, leading to a reduction in cloud eff ective radius over eastern China and a reduced precipitation effi ciency there.

  12. Preferential enhancement of dopamine transmission within the nucleus accumbens shell by cocaine is due to a direct increase in phasic dopamine release events

    OpenAIRE

    Aragona, Brandon J.; Cleaveland, Nathan A.; Stuber, Garret D.; Day, Jeremy J.; Carelli, Regina M.; Wightman, R. Mark

    2008-01-01

    Preferential enhancement of dopamine transmission within the nucleus accumbens (NAc) shell is a fundamental aspect of the neural regulation of cocaine reward. Despite its importance, the nature of this effect is poorly understood. Here, we used fast-scan cyclic voltammetry to examine specific transmission processes underlying cocaine-evoked increases in dopamine transmission within the NAc core and shell. Initially, we examined altered terminal dopamine concentrations following global autorec...

  13. One order enhancement of detectivity in quaternary capped InAs/GaAs quantum dot infrared photodetectors due to vertical coupling of quantum dot layers

    International Nuclear Information System (INIS)

    The spectral and electrical properties of vertically coupled quaternary (InAlGaAs) capped InAs/GaAs quantum dot infrared photodetector with different capping thicknesses are investigated, and compared with a conventional quaternary capped uncoupled detector. Electronic coupling between quantum dot layers leads to a reduction in the ground state energy level and hence greater electronic confinement, which reduces the dark current and enhances the detectivity. These expectations are confirmed by our experimental results. Most significantly one order enhancement in peak detectivity (from 1.1 × 109 cm Hz1/2/W to 2.48 × 1010 cm Hz1/2/W) is observed for optimized coupled quantum dot infrared photodetector compared to uncoupled device. The optimal interlayer barrier thickness which gives maximum detectivity is explained in terms of the interplay between electronic coupling and strain buildup in the heterostructure. - Highlights: • Coupled quaternary capped InAs/GaAs quantum dot detector was compared with uncoupled detector. • Photoluminescence spectra of coupled device exhibit multimodal peaks. • Peak detectivity value of coupled device is 2.48 × 1010 Jones. • Peak detectivity value of uncoupled device is 1.1 × 109 Jones. • Enhanced detectivity observed for coupled detector compared with uncoupled device

  14. Net Anthropogenic Nitrogen Inputs in the Seattle, WA Metropolitan Area

    Science.gov (United States)

    Larson, E. K.; Alberti, M.

    2014-12-01

    Nitrogen loading has been identified as a potential stressor to marine ecosystems of the Puget Sound in the Pacific Northwest, and the Washington State Department of Ecology has estimated that anthropogenic sources of dissolved inorganic nitrogen to the Sound are 2.7 times higher than natural loads (Mohamedali et al. 2011). The Seattle urban area, situated in the southeast of the Sound, has the largest population in the northwestern US. Heavily urbanized along the coast, the 4 counties comprising the region (Snohomish, King, Pierce, and Kitsap) also include forests and agriculture. Urban and agricultural areas tend to have substantial anthropogenic N loading due to fertilizer application, presence of N-fixing vegetation, N atmospheric deposition, and human and other animal waste. To determine the relative contribution of urban vs. rural agricultural activities to N loads from the Seattle region to the Puget Sound, we used the Net Anthropogenic Nitrogen Inputs (NANI) calculator developed by Hong et al. (2011) for the watersheds of this region. The NANI calculator uses nationally available datasets to calculate NANI as the sum of oxidized N deposition, fertilizer application, agricultural N fixation, net food and feed inputs, and net animal and human N consumption. We found that NANI ranged from approximately 100 to 1500 kg m-2 y-1, with some of the highest rates in watersheds with high impervious surface or agricultural areas with N-fixing crops or large fertilizer additions. Many of the agricultural watersheds have intervening low-NANI watershed between themselves and the coast, thus it is likely that agricultural NANI is attenuated before entering the Puget Sound. The urban areas in the region do not have these attenuating watersheds, and so are likely to be the main contributor to the observed total aquatic N yield. This information is helpful for developing policies to reduce N loading to the Sound.

  15. Impact of anthropogenic aerosols on present and future climate

    International Nuclear Information System (INIS)

    Aerosols influence the Earth radiative budget both through their direct effect (scattering and absorption of solar radiation) and their indirect effect (impacts on cloud microphysics). The role of anthropogenic aerosol in climate change has been recognized to be significant when compared to the one of greenhouse gases. Despite many studies on this topic, the assessments of both anthropogenic aerosol radiative forcing and their impacts on meteorological variables are still very uncertain. Major reasons for these uncertainties stem from the insufficient knowledge of the emissions sources and of the processes of formation, transformation and deposition. Models used to study climate are often inadequate to study aerosol processes because of coarse spatial and temporal scales. Uncertainties due to the parameterization of the aerosol are added to the uncertainties in the representation of large scale dynamics and physical processes such as transport, hydrological cycle and radiative budget. To predict, the role of the anthropogenic aerosol impact in the future climate change, I have addressed some of these key uncertainties. In this study, I simulate interactively aerosols processes in a climate model in order to improve the estimation of their direct and indirect effects. I estimate a modification of the top of the atmosphere net flux of 60% for the present period. I also show that, for future projection, the representation of the emissions source is an other important source of error. I assess that aerosols radiative forcing differ by 40% between simulations performed with 2 different emissions inventories. These inventories are representative for a high and a low limit in term of carbonaceous aerosols emissions for the 2050 horizon. (author)

  16. Hidden Markov models for estimating animal mortality from anthropogenic hazards

    Science.gov (United States)

    Carcasses searches are a common method for studying the risk of anthropogenic hazards to wildlife, including non-target poisoning and collisions with anthropogenic structures. Typically, numbers of carcasses found must be corrected for scavenging rates and imperfect detection. ...

  17. Diurnal tracking of anthropogenic CO2 emissions in the Los Angeles basin megacity during spring, 2010

    Directory of Open Access Journals (Sweden)

    K. R. Gurney

    2012-02-01

    Full Text Available Attributing observed CO2 variations to human or natural cause is critical to deducing and tracking emissions from observations. We have used in situ CO2, CO, and planetary boundary layer height (PBLH measurements recorded during the CalNex-LA (CARB et al., 2008 ground campaign of 15 May–15 June 2010, in Pasadena, CA, to deduce the diurnally varying anthropogenic component of observed CO2 in the megacity of Los Angeles (LA. This affordable and simple technique, validated by carbon isotope observations, is shown to robustly attribute observed CO2 variation to anthropogenic or biogenic origin. During CalNex-LA, local fossil fuel combustion contributed up to ~50 % of the observed CO2 enhancement overnight, and ~100 % during midday. This suggests midday column observations over LA, such as those made by satellites relying on reflected sunlight, can be used to track anthropogenic emissions.

  18. Quantifying the Anthropogenic Footprint in Eastern China

    Science.gov (United States)

    Meng, Chunlei; Dou, Youjun

    2016-04-01

    Urban heat island (UHI) is one of the most focuses in urban climate study. The parameterization of the anthropogenic heat (AH) is crucial important in UHI study, but universal method to parameterize the spatial pattern of the AH is lacking now. This paper uses the NOAA DMSP/OLS nighttime light data to parameterize the spatial pattern of the AH. Two experiments were designed and performed to quantify the influences of the AH to land surface temperature (LST) in eastern China and 24 big cities. The annual mean heating caused by AH is up to 1 K in eastern China. This paper uses the relative LST differences rather than the absolute LST differences between the control run and contrast run of common land model (CoLM) to find the drivers. The heating effect of the anthropogenic footprint has less influence on relatively warm and wet cities.

  19. The topographic signature of anthropogenic geomorphic processes

    Science.gov (United States)

    Tarolli, P.; Sofia, G.

    2014-12-01

    Within an abiotic-dominated context, geomorphologic patterns and dynamics are single expressions of trade-offs between the physical resistance forces, and the mechanical and chemical forces related to climate and erosion. Recently, however, it has become essential for the geomorphological community to take into account also biota as a fundamental geomorphologic agent acting from local to regional scales. However, while there is a recent flourishing literature about the impacts of vegetation on geomorphic processes, the study of anthropogenic pressure on geomorphology is still at its early stages. Humans are indeed among the most prominent geomorphic agents, redistributing land surface, and causing drastic changes to the geomorphic organization of the landscape (e.g. intensive agriculture, urbanization), with direct consequences on land degradation and watershed response. The reconstruction or identification of artificial or anthropogenic topographies, therefore, provides a mechanism for quantifying anthropogenic changes to the landscape systems in the context of the Anthropocene epoch. High-resolution topographic data derived from the recent remote sensing technologies (e.g. lidar, SAR, SfM), offer now new opportunities to recognize better understand geomorphic processes from topographic signatures, especially in engineered landscapes where the direct anthropic alteration of processes is significant. It is possible indeed to better recognize human-induced geomorphic and anthropogenic features (e.g. road networks, agricultural terraces), and the connected erosion. The study presented here may allow improved understanding and targeted mitigation of the processes driving geomorphic changes during urban development and help guide future research directions for development-based watershed studies. Human society is deeply affecting the environment with consequences on the landscape. It is therefore fundamental to establish greater management control over the Earth

  20. Modeling Fallout of Anthropogenic I-129

    DEFF Research Database (Denmark)

    Englund, Edvard; Aldahan, Als; Possnert, Göran; Haltia-Hovi, Eeva; Hou, Xiaolin; Renberg, Ingmar; Saarinen, Timo

    2008-01-01

    Despite the relatively well-recognized emission rates of the anthropogenic 1291, there is little knowledge about the temporal fallout patterns and magnitude of fluxes since the start of the atomic era at the early 1940s. We here present measurements of annual 1291 concentrations in sediment...... atmosphere is derived for pertinent sea areas (English Channel, Irish Sea, and North Sea), which is estimated at 0.04 to 0.21 y(-1)....

  1. Continental anthropogenic primary particle number emissions

    OpenAIRE

    P. Paasonen; Kupiainen, K.; Z. Klimont; Visshedijk, A.; H. A. C. Denier van der Gon; M. Amann

    2016-01-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future, anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS model. This implementation allows for global estimates of particle number ...

  2. Continental anthropogenic primary particle number emissions

    OpenAIRE

    Paasonen, Pauli; Kupiainen, Kaarle; Klimont, Zbigniew; Visschedijk, Antoon; Denier van der Gon, Hugo A. C.; Amann, Markus

    2016-01-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas–Air Pollution Interactions and Synergies) model. This im...

  3. Magnetization enhancement due to incorporation of non-magnetic nitrogen content in (Co84Zr16)Nx nano-composite films

    OpenAIRE

    Jitendra Singh; Rishabh Shukla; Anita Bagri; Rajendra S. Dhaka; Jamil Akhtar

    2016-01-01

    We report the magnetic, electronic, and structural properties of nano-composite (Co84Zr16)Nx or CZN films prepared by reactive co-sputter deposition method. As-deposited CZN films have shown enhancement in magnetization (Ms) with incorporation of nitrogen content, which is related to the evolution of nano-composite phase. X-ray diffraction study has confirmed poly-crystalline growth of CZN films with fcc(331) and fcc(422) phases. High-resolution transmission electron microscope study reveals...

  4. Enhancement of spin wave excitation by spin currents due to thermal gradient and spin pumping in yttrium iron garnet/Pt

    Science.gov (United States)

    da Silva, G. L.; Vilela-Leão, L. H.; Rezende, S. M.; Azevedo, A.

    2013-01-01

    We investigate the interplay between spin currents produced by thermal gradients and spin pumping in hybrid yttrium iron garnet/Pt structures (YIG/Pt). By combining a spin pumping experiment with the application of a temperature gradient, we observe the excitation of local spin wave modes at the YIG/Pt interface. Strong enhancement of these modes was observed when the temperature gradient was applied along one direction and attenuation was observed by reversing the temperature gradient. The results provide support for a recent theoretical proposal, in which some spin wave modes are preferentially excited by spin currents traversing a YIG/Pt interface.

  5. Laser assisted decontamination of metal surface: Evidence of increased surface absorptivity due to field enhancement caused by transparent/semi-transparent contaminant particulates

    International Nuclear Information System (INIS)

    Small signal absorption measurements of the incident coherent radiation by the metal surface have revealed an increase in the absorption by the surface in presence of transparent/semi-transparent particulates on it. This effect, identified as field enhanced surface absorption, has been found to increase with reduction in the average particulate size. Consequently higher laser assisted removal efficiency of contamination from a metal surface has been observed for smaller contaminant particulates. These measurements have been carried out utilizing coherent radiations of two different wavelengths so chosen that for one the particulates are totally transparent while for the other they are partially transparent.

  6. Blue whales respond to anthropogenic noise.

    Science.gov (United States)

    Melcón, Mariana L; Cummins, Amanda J; Kerosky, Sara M; Roche, Lauren K; Wiggins, Sean M; Hildebrand, John A

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood. PMID:22393434

  7. Blue whales respond to anthropogenic noise.

    Directory of Open Access Journals (Sweden)

    Mariana L Melcón

    Full Text Available Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.

  8. Enhanced photoelectrochemical performance of WO{sub 3}/Ti photoanode due to in situ formation of a thin interfacial composite layer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Jae, E-mail: wjlee@keri.re.kr [Battery Research Center, Korea Electrotechnology Research Institute (KERI), Changwon 641-120 (Korea, Republic of); Shinde, Pravin S.; Go, Geun Ho; Doh, Chil Hoon [Battery Research Center, Korea Electrotechnology Research Institute (KERI), Changwon 641-120 (Korea, Republic of)

    2013-04-01

    Nanostructured WO{sub 3} thin films were prepared on titanium sheet substrates using a doctor blade technique. X-ray diffraction, Raman and field emission scanning electron microscopy studies revealed that the synthesized WO{sub 3} films are having monoclinic crystal structure, porous, polycrystalline with average grain size of ∼50 nm. The photoelectrochemical responses of WO{sub 3} films prepared on treated Ti sheets were recorded in 0.5 M H{sub 2}SO{sub 4} electrolyte under simulated 100 mW/cm{sup 2} illumination. WO{sub 3} film prepared on polished Ti sheet showed considerable enhancement in photocurrent as compared to WO{sub 3} films made on unpolished and pre-oxidized Ti sheets. These results suggest that in situ formation of a thin WO{sub x}–TiO{sub y} interfacial composite layer and improved adhesion of WO{sub 3} nanoparticles owing to increased reactive sites on polished Ti substrate play a significant role in enhancing the photoresponse. Such photoanodes are potential candidates in photoelectrochemical water splitting system for hydrogen generation.

  9. Natural and anthropogenic hydrocarbons in the White sea ecosystem

    International Nuclear Information System (INIS)

    An investigation of aliphatic hydrocarbons (AHC) and polycyclic aromatic hydrocarbons (PAH) concentrations in the White Sea was presented. The study was conducted to determine natural and anthropogenic hydrocarbon (HC) concentrations in order to aid in future zoning plans. Hydrocarbons were extracted from samples of aerosols, ice, water, particulate matter, phyto- and zooplankton, and bottom sediments. Results of the study suggested that HC concentrations in aerosols above the White Sea were lower than in marine aerosols above the southeastern Atlantic and lower than Alkane concentrations in aerosols in the Mediterranean Sea. A study of PAH behaviour in Northern Dvina estuaries showed that the submicron fractions contained light polyarenes. Particulate matter collected in sedimentation traps was enriched in phenanthrene, fluoranthene, and pyrene. Aliphatic HC enrichment was due to the presence of phytoplankton and other microorganisms. Between 54 per cent and 85 per cent of initial organic matter was consumed during diagenesis in the bottom sediments, indicating a high rate of HC transformation. It was suggested that the majority of oil HC transported with river water is precipitated. Fluoranthene was the dominant PAH in the study, and was assumed to be caused by natural transformation of PAH composition during distant atmospheric transport. Pyrogenic contamination of the bottom sediments was attributed to an aluminium plant. It was concluded that the detection of significant amounts of HC is not direct evidence of their anthropogenic origins. 31 refs., 3 tabs., 7 figs

  10. Modeling study on the transport of summer dust and anthropogenic aerosols over the Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Y. Liu

    2015-05-01

    Full Text Available The Tibetan Plateau (TP is located at the juncture of several important natural and anthropogenic aerosol sources. Satellites have observed substantial dust and anthropogenic aerosols in the atmosphere during summer over the TP. These aerosols have distinct effects on the earth's energy balance, microphysical cloud properties, and precipitation rates. To investigate the transport of summer dust and anthropogenic aerosols over the TP, we combined the Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS with a non-hydrostatic regional model (NHM. The model simulation shows heavily loaded dust aerosols over the northern slope and anthropogenic aerosols over the southern slope and to the east of the TP. The dust aerosols are primarily mobilized around the Taklimakan Desert, where a portion of the aerosols are transported eastward due to the northwesterly current; simultaneously, a portion of the particles are transported northward when a second northwesterly current becomes northeasterly because of the topographic blocking of the northern slope of the TP. Because of the strong upward current, dust plumes can extend upward to approximately 7–8 km a.s.l. over the northern slope of the TP. When a dust event occurs, anthropogenic aerosols that entrain into the southwesterly current via the Indian summer monsoon are transported from India to the southern slope of the TP. Simultaneously, a large amount of anthropogenic aerosols is also transported from eastern China to east of the TP by easterly winds. An investigation on the transport of dust and anthropogenic aerosols over the plateau may provide the basis for determining aerosol impacts on summer monsoons and climate systems.

  11. Modeling study on the transport of summer dust and anthropogenic aerosols over the Tibetan Plateau

    Science.gov (United States)

    Liu, Y.; Sato, Y.; Jia, R.; Xie, Y.; Huang, J.; Nakajima, T.

    2015-11-01

    The Tibetan Plateau (TP) is located at the juncture of several important natural and anthropogenic aerosol sources. Satellites have observed substantial dust and anthropogenic aerosols in the atmosphere during summer over the TP. These aerosols have distinct effects on the earth's energy balance, microphysical cloud properties, and precipitation rates. To investigate the transport of summer dust and anthropogenic aerosols over the TP, we combined the Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS) with a non-hydrostatic regional model (NHM). The model simulation shows heavily loaded dust aerosols over the northern slope and anthropogenic aerosols over the southern slope and the east of the TP. The dust aerosols are primarily mobilized around the Taklimakan Desert, where a portion of the aerosols are transported eastward due to the northwesterly current; simultaneously, a portion of the particles are transported southward when a second northwesterly current becomes northeasterly because of the topographic blocking of the northern slope of the TP. Because of the strong upward current, dust plumes can extend upward to approximately 7-8 km a.s.l. over the northern slope of the TP. When a dust event occurs, anthropogenic aerosols that entrained into the southwesterly current via the Indian summer monsoon are transported from India to the southern slope of the TP. Simultaneously, a large amount of anthropogenic aerosol is also transported from eastern China to the east of the TP by easterly winds. An investigation on the transport of dust and anthropogenic aerosols over the plateau may provide the basis for determining aerosol impacts on summer monsoons and climate systems.

  12. Anthropogenic features and hillslope processes interaction

    Science.gov (United States)

    Tarolli, Paolo; Sofia, Giulia

    2016-04-01

    Topography emerges as a result of natural driving forces, but some human activities (such as mining, agricultural practices and the construction of road networks) directly or indirectly move large quantities of soil, which leave clear topographic signatures embedded on the Earth's morphology. These signatures can cause drastic changes to the geomorphological organization of the landscape, with direct consequences on Earth surface processes (Tarolli and Sofia, 2016). To this point, the present research investigates few case studies highlighting the influences of anthropogenic topographic signatures on hillslope processes, and it shows the effectiveness of High-Resolution Topography (HRT) derived from the recent remote sensing technologies (e.g. lidar, satellite, structure from motion photogrammetry), to better understand this interaction. The first example is related to agricultural terraces. In recent times, terraced areas acquired a new relevance to modern concerns about erosion and land instability, being the agricultural land mostly threatened by abandonment or intensification and specialization of agriculture, resulting in more landslide-prone bench terraces, or heavy land levelling with increased erosion. The second case study discusses about the role of agricultural and forest roads on surface erosion and landslides. The third case study investigates geomorphic processes in an open pit mine. In all case studies, HRT served as the basis for the development of new methodologies able to recognize and analyze changes on Earth surface processes along hillslopes. The results show how anthropogenic elements have crucial effects on sediment production and sediment delivery, also influencing the landscape connectivity. The availability of HRT can improve our ability to actually model anthropogenic morphologies, quantify them, and analyse the links between anthropogenic elements and geomorphic processes. The results presented here, and the creation and dissemination of

  13. Anthropogenic moisture production and its effect on boundary layer circulations over New York City

    International Nuclear Information System (INIS)

    A heat and moisture excess over New York City is shown to exist by the analysis of helicopter soundings of temperature and wet bulb depression. The magnitude of the temporal and spatial distribution of anthropogenic moisture emissions in New York City were estimated from fuel usage data. The URBMET urban boundary layer model was used to evaluate the effects on the dynamics of the urban boundary layer resulting from the observed urban moisture excess. Work is currently in progress which seeks to determine the fraction of the observed moisture excess over New York that is due to anthropogenic sources. (auth)

  14. Assessing the osteoblast transcriptome in a model of enhanced bone formation due to constitutive Gs–G protein signaling in osteoblasts

    International Nuclear Information System (INIS)

    G protein-coupled receptor (GPCR) signaling in osteoblasts (OBs) is an important regulator of bone formation. We previously described a mouse model expressing Rs1, an engineered constitutively active Gs-coupled GPCR, under the control of the 2.3 kb Col I promoter. These mice showed a dramatic age-dependent increase in trabecular bone of femurs. Here, we further evaluated the effects of enhanced Gs signaling in OBs on intramembranous bone formation by examining calvariae of 1- and 9-week-old Col1(2.3)/Rs1 mice and characterized the in vivo gene expression specifically occurring in osteoblasts with activated Gs G protein-coupled receptor signaling, at the cellular level rather than in a whole bone. Rs1 calvariae displayed a dramatic increase in bone volume with partial loss of cortical structure. By immunohistochemistry, Osterix was detected in cells throughout the inter-trabecular space while Osteocalcin was expressed predominantly in cells along bone surfaces, suggesting the role of paracrine mediators secreted from OBs driven by 2.3 kb Col I promoter could influence early OB commitment, differentiation, and/or proliferation. Gene expression analysis of calvarial OBs revealed that genes affected by Rs1 signaling include those encoding proteins important for cell differentiation, cytokines and growth factors, angiogenesis, coagulation, and energy metabolism. The set of Gs-GPCRs and other GPCRs that may contribute to the observed skeletal phenotype and candidate paracrine mediators of the effect of Gs signaling in OBs were also determined. Our results identify novel detailed in vivo cellular changes of the anabolic response of the skeleton to Gs signaling in mature OBs. - Highlights: • OB expression of an engineered Gs-coupled receptor dramatically increases bone mass. • We investigated the changes in gene expression in vivo in enhanced OB Gs signaling. • Genes in cell cycle and transcription were increased in enhanced OB Gs signaling. • GPCRs and paracrine

  15. Assessing the osteoblast transcriptome in a model of enhanced bone formation due to constitutive G{sub s}–G protein signaling in osteoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Wattanachanya, Lalita, E-mail: lalita_md@yahoo.com [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok (Thailand); Wang, Liping, E-mail: lipingwang05@yahoo.com [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); Millard, Susan M., E-mail: susan.millard@mater.uq.edu.au [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); Lu, Wei-Dar, E-mail: weidar_lu@yahoo.com [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); O’Carroll, Dylan, E-mail: dylancocarroll@gmail.com [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States); Hsiao, Edward C., E-mail: Edward.Hsiao@ucsf.edu [Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, CA (United States); Conklin, Bruce R., E-mail: bconklin@gladstone.ucsf.edu [Gladstone Institute of Cardiovascular Disease, San Francisco, CA (United States); Department of Medicine, University of California, San Francisco, CA (United States); Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA (United States); Nissenson, Robert A., E-mail: Robert.Nissenson@ucsf.edu [Endocrine Research Unit, Veterans Affairs Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA (United States)

    2015-05-01

    G protein-coupled receptor (GPCR) signaling in osteoblasts (OBs) is an important regulator of bone formation. We previously described a mouse model expressing Rs1, an engineered constitutively active G{sub s}-coupled GPCR, under the control of the 2.3 kb Col I promoter. These mice showed a dramatic age-dependent increase in trabecular bone of femurs. Here, we further evaluated the effects of enhanced G{sub s} signaling in OBs on intramembranous bone formation by examining calvariae of 1- and 9-week-old Col1(2.3)/Rs1 mice and characterized the in vivo gene expression specifically occurring in osteoblasts with activated G{sub s} G protein-coupled receptor signaling, at the cellular level rather than in a whole bone. Rs1 calvariae displayed a dramatic increase in bone volume with partial loss of cortical structure. By immunohistochemistry, Osterix was detected in cells throughout the inter-trabecular space while Osteocalcin was expressed predominantly in cells along bone surfaces, suggesting the role of paracrine mediators secreted from OBs driven by 2.3 kb Col I promoter could influence early OB commitment, differentiation, and/or proliferation. Gene expression analysis of calvarial OBs revealed that genes affected by Rs1 signaling include those encoding proteins important for cell differentiation, cytokines and growth factors, angiogenesis, coagulation, and energy metabolism. The set of G{sub s}-GPCRs and other GPCRs that may contribute to the observed skeletal phenotype and candidate paracrine mediators of the effect of G{sub s} signaling in OBs were also determined. Our results identify novel detailed in vivo cellular changes of the anabolic response of the skeleton to G{sub s} signaling in mature OBs. - Highlights: • OB expression of an engineered G{sub s}-coupled receptor dramatically increases bone mass. • We investigated the changes in gene expression in vivo in enhanced OB G{sub s} signaling. • Genes in cell cycle and transcription were increased in

  16. Climatic response to anthropogenic sulphate aerosols versus well-mixed greenhouse gases from 1850 to 2000 AD in CLIMBER-2

    OpenAIRE

    Bauer, Eva; Petoukhov, Vladimir; Ganopolski, Andrey; Eliseev, Alexey V.

    2011-01-01

    The Earth system model CLIMBER-2 is extended by a scheme for calculating the climatic response to anthropogenic sulphur dioxide emissions. The scheme calculates the direct radiative forcing, the first indirect cloud albedo effect, and the second indirect cloud lifetime effect induced by geographically resolved sulphate aerosol burden. The simulated anthropogenic sulphate aerosol burden in the year 2000 amounts to 0.47 TgS. The best guesses for the radiative forcing due to the direct effect ar...

  17. Fatty Acid Incubation of Myotubues from Humans with Type 2 Diabetes Leads to Enhanced Release of Beta Oxidation Products Due to Impaired Fatty Acid Oxidation

    DEFF Research Database (Denmark)

    Wensaas, Andreas J; Rustan, Arild C; Just, Marlene;

    2008-01-01

    Objective: Increased availability of fatty acids is important for accumulation of intracellular lipids and development of insulin resistance in human myotubes. It is unknown whether different types of fatty acids like eicosapentaenoic acid (EPA) or tetradecylthioacetic acid (TTA) influence these...... processes. Research Design and Methods: We examined fatty acid and glucose metabolism, and gene expression in cultured human skeletal muscle cells from control and T2D individuals after four days preincubation with EPA or TTA. Results: T2D myotubes exhibited reduced formation of CO(2) from palmitic acid (PA......), whereas release of beta-oxidation products was unchanged at baseline, but significantly increased with respect to control myotubes after preincubation with TTA and EPA. Preincubation with TTA enhanced both complete (CO(2)) and beta-oxidation of PA, whereas EPA increased only beta-oxidation significantly...

  18. Alpha power effects on energy confinement time and ignition, and enhancement of ion neoclassical heat conduction due to electron and superthermal ion energy scattering collisions

    International Nuclear Information System (INIS)

    In Part A of the paper a purely theoretical model is adopted for the local heat diffusivities χe and χi. The global τE is constructed after Callen et al. and is used in a zero dimensional ignition power balance to study alpha power and fast alpha loss effects on ignition. The Horton-Choi-Yushmanov-Parail model for χe permits ignition in a CIT-like tokamak with B = 13.5 T, Ip = 18 MA, if the fast alpha losses and the ηi mode can be controlled. Part B considers the extra components of neoclassical ion heat conduction driven by energy scattering collisions with electrons and superthermal ions. These components are important in auxiliary heated discharges and can be the most important if the plasma ion distribution has an enhanced non-Maxwellian tail. (author). 19 refs, 4 figs, 1 tab

  19. Contributions of natural and anthropogenic forcing to changes in temperature extremes over the United States

    Science.gov (United States)

    Meehl, Gerald A.; Arblaster, Julie M.; Tebaldi, Claudia

    2007-10-01

    Observations averaged over the U.S. for the second half of the 20th century have shown a decrease of frost days, an increase in growing season length, an increase in the number of warm nights, and an increase in heat wave intensity. For the first three, a nine member multi-model ensemble shows similar changes over the U.S. in 20th century experiments that combine anthropogenic and natural forcings, though the relative contributions of each are unclear. Here we show results from two global coupled climate models run with anthropogenic and natural forcings separately. Averaged over the continental U.S., they show that the observed changes in the four temperature extremes are accounted for with anthropogenic forcings, but not with natural forcings (even though there are some differences in the details of the forcings). This indicates that most of the changes in temperature extremes over the U.S. are likely due to human activity.

  20. Nonlinear effects of anthropogenic aerosol and urban land surface forcing on spring climate in eastern China

    Science.gov (United States)

    Deng, Jiechun; Xu, Haiming; Zhang, Leying

    2016-05-01

    Anthropogenic aerosols and urban land cover change induce opposite thermal effects on the atmosphere near surface as well as in the troposphere. One can think of these anthropogenic effects as composed of two parts: the individual effect due to an individual anthropogenic forcing and the nonlinear effects resulting from the coexistence of two forcing factors. In this study, we explored the role of such nonlinear effects in affecting East Asian climate, as well as individual forcing effects, using the Community Atmosphere Model version 5.1 coupled with the Community Land Model version 4. Atmospheric responses were simulated by including anthropogenic aerosol emission only, urban cover only, or the combination of the two, over eastern China. Results showed that nonlinear responses were different from any effects by an individual forcing or the linear combination of individual responses. The nonlinear interaction could generate cold horizontal temperature advection to cool the troposphere, which induced anomalous subsidence along the Yangtze River Valley (YRV). This anomalous vertical motion, together with a weakened low-level southwesterly, favored below-normal (above-normal) rainfall over the YRV (southern China), shifting the spring rain belt southward. The resultant diabatic cooling, in turn, amplified the anomalous descent and further decreased tropospheric temperature over the YRV, forming a positive feedback loop to maintain the nonlinear effects. Consequently, the nonlinear effects acted to reduce the climate anomalies from a simple linear combination of two individual effects and played an important role in regional responses to one anthropogenic forcing when the other is prescribed.

  1. Distinct energy budgets for anthropogenic and natural changes during global warming hiatus

    Science.gov (United States)

    Xie, Shang-Ping; Kosaka, Yu; Okumura, Yuko M.

    2016-01-01

    The Earth's energy budget for the past four decades can now be closed, and it supports anthropogenic greenhouse forcing as the cause for climate warming. However, closure depends on invoking an unrealistically large increase in aerosol cooling during the so-called global warming hiatus since the late 1990s (refs ,) that was due partly to tropical Pacific Ocean cooling. The difficulty with this closure lies in the assumption that the same climate feedback applies to both anthropogenic warming and natural cooling. Here we analyse climate model simulations with and without anthropogenic increases in greenhouse gas concentrations, and show that top-of-the-atmosphere radiation and global mean surface temperature are much less tightly coupled for natural decadal variability than for the greenhouse-gas-induced response, implying distinct climate feedback between anthropogenic warming and natural variability. In addition, we identify a phase difference between top-of-the-atmosphere radiation and global mean surface temperature such that ocean heat uptake tends to slow down during the surface warming hiatus. This result deviates from existing energy theory but we find that it is broadly consistent with observations. Our study highlights the importance of developing metrics that distinguish anthropogenic change from natural variations to attribute climate variability and to estimate climate sensitivity from observations.

  2. Direct Radiative Forcing of Anthropogenic Aerosols over Oceans from Satellite Observations

    Institute of Scientific and Technical Information of China (English)

    CHEN Lin; SHI Guangyu; QIN Shiguang; YANG Su; ZHANG Peng

    2011-01-01

    Anthropogenic aerosols play an important role in the atmospheric energy balance. Anthropogenic aerosol optical depth (AOD) and its accompanying shortwave radiative forcing (RF) are usually simulated by numerical models. Recently, with the development of space-borne instruments and sophisticated retrieval algorithms, it has become possible to estimate aerosol radiative forcing based on satellite observations. In this study, we have estimated shortwave direct radiative forcing due to anthropogenic aerosols over oceans in all-sky conditions by combining clouds and the Single Scanner Footprint data of the Clouds and Earth's Radiant Energy System (CERES/SSF) experiment, which provide measurements of upward shortwave fluxes at the top of atmosphere, with Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol and cloud products. We found that globally averaged aerosol radiative forcing over oceans in the clear-sky conditions and all-sky conditions were -1.03±0.48 W m-2 and -0.34 ±0.16 W m-2, respectively. Direct radiative forcing by anthropogenic aerosols shows large regional and seasonal variations. In some regions and in particular seasons, the magnitude of direct forcing by anthropogenic aerosols can be comparable to the forcing of greenhouse gases. However, it shows that aerosols caused the cooling effect, rather than warming effect from global scale, which is different from greenhouse gases.

  3. Asian anthropogenic dust and its climate effect (Invited)

    Science.gov (United States)

    Huang, J.; Liu, J.; Chen, B.

    2013-12-01

    Anthropogenic dust originates mainly from areas of localized human disturbance, such as traffic-on-roads, agricultural fields, grazing, military installations, construction sites, and off-road vehicle areas. To understand historical and possible future changes in dust emissions, the percentage of atmospheric dust load originating from anthropogenic source and its distribution must be quantified. CALIPSO lidar, which shoots a laser into the atmosphere, provides new insight into the detection of anthropogenic dust emission. Here, we present the distribution of Asian anthropogenic dust emissions and its relation to human activity by using CALIPSO lidar measurements. We found that the local anthropogenic dust aerosols account for significant portion of the total dust burden in the atmosphere. The anthropogenic dust emissions mainly occur over the heavy human activity and poor ecosystem region, such as semi-arid region. The impact of Asian anthropogenic dust on regional climate will also be discussed in this talk.

  4. Impaired mitochondrial Ca2+ homeostasis in respiratory chain-deficient cells but efficient compensation of energetic disadvantage by enhanced anaerobic glycolysis due to low ATP steady state levels

    International Nuclear Information System (INIS)

    Energy-producing pathways, adenine nucleotide levels, oxidative stress response and Ca2+ homeostasis were investigated in cybrid cells incorporating two pathogenic mitochondrial DNA point mutations, 3243A > G and 3302A > G in tRNALeu(UUR), as well as Rho0 cells and compared to their parental 143B osteosarcoma cell line. All cells suffering from a severe respiratory chain deficiency were able to proliferate as fast as controls. The major defect in oxidative phosphorylation was efficiently compensated by a rise in anaerobic glycolysis, so that the total ATP production rate was preserved. This enhancement of glycolysis was enabled by a considerable decrease of cellular total adenine nucleotide pools and a concomitant shift in the AMP + ADP/ATP ratios, while the energy charge potential was still in the normal range. Further important consequences were an increased production of superoxide which, however, was neither escorted by major changes in the antioxidative defence systems nor was it leading to substantial oxidative damage. Most interestingly, the lowered mitochondrial membrane potential led to a disturbed intramitochondrial calcium homeostasis, which most likely is a major pathomechanism in mitochondrial diseases

  5. Enhanced antibody responses to a detoxified lipopolysaccharide-group B meningococcal outer membrane protein vaccine are due to synergistic engagement of Toll-like receptors.

    Science.gov (United States)

    Chen, Wilbur H; Basu, Subhendu; Bhattacharjee, Apurba K; Cross, Alan S

    2010-10-01

    When given passively or elicited actively, antibodies induced by a detoxified Escherichia coli Rc chemotype (J5) mutant lipopolysaccharide (J5dLPS)-group B meningococcal outer membrane protein (OMP) complex vaccine protected animals from lethal sepsis. The protection from sepsis is believed to be dependent on high levels of antibodies against the core glycolipid (CGL), a region of LPS that is rather conserved among Enterobacteriaceae. The addition of unmethylated deoxycytidyl-deoxyguanosine dinucleotide (CpG)-containing oligodeoxynucleotides (ODN) was used as an immuno-adjuvant to improve antibody responses. In preparation for a Phase I human trial, we elucidated potential contributions by which the sepsis vaccine (J5dLPS-OMP) and CpG ODN might enhance the antibody response and provide evidence that the generation of immune responses is Toll-like receptor (TLR) dependent. Toll-like receptor 2, TLR4, and TLR9 were each essential for generating robust cytokine and antibody responses. The signature cytokine of dendritic cells, interleukin-12, was one of the cytokines that demonstrated synergy with the optimal TLR ligand/ engagement combination. We conclude that the involvement of multiple TLRs upon immunization was critical for the generation of optimal antibody responses. These observations provide further evidence for the inclusion of innate immune-based adjuvants during the development of next-generation vaccines. PMID:19822632

  6. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes)

    OpenAIRE

    Carlitz, Esther H. D.; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C.; van Schaik, Carel P.

    2016-01-01

    Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with h...

  7. Microbial copper reduction method to scavenge anthropogenic radioiodine

    Science.gov (United States)

    Lee, Seung Yeop; Lee, Ji Young; Min, Je Ho; Kim, Seung Soo; Baik, Min Hoon; Chung, Sang Yong; Lee, Minhee; Lee, Yongjae

    2016-06-01

    Unexpected reactor accidents and radioisotope production and consumption have led to a continuous increase in the global-scale contamination of radionuclides. In particular, anthropogenic radioiodine has become critical due to its highly volatile mobilization and recycling in global environments, resulting in widespread, negative impact on nature. We report a novel biostimulant method to effectively scavenge radioiodine that exhibits remarkable selectivity for the highly difficult-to-capture radioiodine of >500-fold over other anions, even under circumneutral pH. We discovered a useful mechanism by which microbially reducible copper (i.e., Cu2+ to Cu+) acts as a strong binder for iodide-iodide anions to form a crystalline halide salt of CuI that is highly insoluble in wastewater. The biocatalytic crystallization of radioiodine is a promising way to remove radioiodine in a great capacity with robust growth momentum, further ensuring its long-term stability through nuclear I‑ fixation via microcrystal formation.

  8. Anthropogenic radionuclides in seawater of the Far Eastern Seas

    International Nuclear Information System (INIS)

    Large quantities of radioactive wastes have been dumped in the Far Eastern Seas by the former Soviet Union and the Russian Federation, and small amounts of radioactive wastes have been dumped by Japan and the Republic of Korea. In order to investigate the concentrations of anthropogenic radionuclides in the nine dumping areas, a second expedition was conducted in 1995 by Japan, the Republic of Korea, the Russian Federation and IAEA, following the first expedition in 1994. The results show that 137Cs, 90Sr and 239+240Pu concentrations in surface and bottom waters at dumping areas do not significantly differ from the values observed in background areas, and from historical values. There is no clear effect of possible contamination due to radioactive waste dumping. The concentrations and water column inventories of 137Cs, 90Sr and 239+240Pu in the Far Eastern seas are controlled by physical oceanic processes such as horizontal transport and biogeochemical processes such as scavenging

  9. Microbial copper reduction method to scavenge anthropogenic radioiodine

    Science.gov (United States)

    Lee, Seung Yeop; Lee, Ji Young; Min, Je Ho; Kim, Seung Soo; Baik, Min Hoon; Chung, Sang Yong; Lee, Minhee; Lee, Yongjae

    2016-01-01

    Unexpected reactor accidents and radioisotope production and consumption have led to a continuous increase in the global-scale contamination of radionuclides. In particular, anthropogenic radioiodine has become critical due to its highly volatile mobilization and recycling in global environments, resulting in widespread, negative impact on nature. We report a novel biostimulant method to effectively scavenge radioiodine that exhibits remarkable selectivity for the highly difficult-to-capture radioiodine of >500-fold over other anions, even under circumneutral pH. We discovered a useful mechanism by which microbially reducible copper (i.e., Cu2+ to Cu+) acts as a strong binder for iodide-iodide anions to form a crystalline halide salt of CuI that is highly insoluble in wastewater. The biocatalytic crystallization of radioiodine is a promising way to remove radioiodine in a great capacity with robust growth momentum, further ensuring its long-term stability through nuclear I− fixation via microcrystal formation. PMID:27311370

  10. Enhancement of photocurrents due to the oxidation of water and organic compounds at BiZn{sub 2}VO{sub 6} particulate thin film electrodes by treatment with a TiCl{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Liu Haimei, E-mail: liuhm@mail.buct.edu.c [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Division of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Imanishi, Akihito [Division of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Yang Wensheng [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Nakato, Yoshihiro [Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2010-05-01

    Photocurrents due to water oxidation at BiZn{sub 2}VO{sub 6} (E{sub g} 2.4 eV) particulate thin film electrodes were largely enhanced by pre-treatment with an aqueous TiCl{sub 4} solution. Photocurrents for BiZn{sub 2}VO{sub 6} electrodes with no TiCl{sub 4} treatment were also enhanced by the addition of organic compounds such as methanol and trimethyl amine to the aqueous electrolyte. Interestingly, such enhanced photocurrents by organic compounds were further enhanced by the TiCl{sub 4} pre-treatment. EDAX and SEM investigations showed the formation of a flock-like TiO{sub 2} overlayer on BiZn{sub 2}VO{sub 6} particles after the TiCl{sub 4} treatment. The photocurrent enhancement by the TiCl{sub 4} pre-treatment is thus mainly attributed to the necking effect of the flock-like TiO{sub 2} overlayer, which facilitates the transport of photogenerated electrons within the BiZn{sub 2}VO{sub 6} particulate thin film electrode.

  11. Orally Administered Salacia reticulata Extract Reduces H1N1 Influenza Clinical Symptoms in Murine Lung Tissues Putatively Due to Enhanced Natural Killer Cell Activity.

    Science.gov (United States)

    Romero-Pérez, Gustavo A; Egashira, Masayo; Harada, Yuri; Tsuruta, Takeshi; Oda, Yuriko; Ueda, Fumitaka; Tsukahara, Takamitsu; Tsukamoto, Yasuhiro; Inoue, Ryo

    2016-01-01

    Influenza is a major cause of respiratory tract infection. Although most cases do not require further hospitalization, influenza periodically causes epidemics in humans that can potentially infect and kill millions of people. To countermeasure this threat, new vaccines need to be developed annually to match emerging influenza viral strains with increased resistance to existing vaccines. Thus, there is a need for finding and developing new anti-influenza viral agents as alternatives to current treatments. Here, we tested the antiviral effects of an extract from the stems and roots of Salacia reticulata (SSRE), a plant rich in phytochemicals, such as salacinol, kotalanol, and catechins, on H1N1 influenza virus-infected mice. Following oral administration of 0.6 mg/day of SSRE, the incidence of coughing decreased in 80% of mice, and only one case of severe pulmonary inflammation was detected. Moreover, when compared with mice given Lactobacillus casei JCM1134, a strain previously shown to help increase in vitro natural killer (NK) cell activity, SSRE-administered mice showed greater and equal NK cell activity in splenocytes and pulmonary cells, respectively, at high effector cell:target cell ratios. Next, to test whether or not SSRE would exert protective effects against influenza in the absence of gut microbiota, mice were given antibiotics before being inoculated influenza virus and subsequently administered SSRE. SSRE administration induced an increase in NK cell activity in splenocytes and pulmonary cells at levels similar to those detected in mice not treated with antibiotics. Based on our results, it can be concluded that phytochemicals in the SSRE exerted protective effects against influenza infection putatively via modulation of the immune response, including enhancement of NK cell activity, although some protective effects were not necessarily through modulation of gut microbiota. Further investigation is necessary to elucidate the molecular mechanisms

  12. Segmental Difference of the Hepatic Fibrosis from Chronic Viral Hepatitis due to Hepatitis B versus C Virus Infection: Comparison Using Dual Contrast Material-Enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jae Ho; Yu, Jeong Sik; Chung, Jae Joon; Kim, Joo Hee; Kim, Ki Whang [Gangnam Severance Hospital, Yensei University College of Medicine, Seoul (Korea, Republic of)

    2011-08-15

    We wanted to identify the geographic differences in hepatic fibrosis and their associations with the atrophy-hypertrophy complex in patients with chronic viral hepatitis using the dual-contrast material-enhanced MRI (DC-MRI) with gadopentetate dimeglumine and ferucarbotran. Patients with chronic C (n = 22) and B-viral hepatitis (n = 35) were enrolled for determining the subjective grade of fibrosis (the extent and thickness of fibrotic reticulations) in the right lobe (RL), the caudate lobe (CL), the medial segment (MS) and the lateral segment (LS) of the liver, with using a 5-grade scale, on the gradient echo T2-weighted images of DC-MRI. The fibrosis grades of different segments were compared using the Kruskal-Wallis test followed by post-hoc analysis to establish the segment-by-segment differences. The incidences of two pre-established morphologic signs of cirrhosis were also compared with each other between the two groups of patients. There were significant intersegmental differences in fibrosis grades of the C-viral group (p = 0.005), and the CL showed lower fibrosis grades as compared with the grades of the RL and MS, whereas all lobes were similarly affected in the B-viral group (p = 0.221). The presence of a right posterior hepatic notch was significantly higher in the patients with intersegmental differences of fibrosis between the RL and the CL (19 out of 25, 76%) than those without such differences (6 out of 32, 19%) (p < 0.001). An expanded gallbladder fossa showed no significant relationship (p = 0.327) with the segmental difference of the fibrosis grades between the LS and the MS. The relative lack of fibrosis in the CL with more advanced fibrosis in the RL can be a distinguishing feature to differentiate chronic C-viral hepatitis from chronic B-viral hepatitis and this is closely related to the presence of a right posterior hepatic notch.

  13. Segmental Difference of the Hepatic Fibrosis from Chronic Viral Hepatitis due to Hepatitis B versus C Virus Infection: Comparison Using Dual Contrast Material-Enhanced MRI

    International Nuclear Information System (INIS)

    We wanted to identify the geographic differences in hepatic fibrosis and their associations with the atrophy-hypertrophy complex in patients with chronic viral hepatitis using the dual-contrast material-enhanced MRI (DC-MRI) with gadopentetate dimeglumine and ferucarbotran. Patients with chronic C (n = 22) and B-viral hepatitis (n = 35) were enrolled for determining the subjective grade of fibrosis (the extent and thickness of fibrotic reticulations) in the right lobe (RL), the caudate lobe (CL), the medial segment (MS) and the lateral segment (LS) of the liver, with using a 5-grade scale, on the gradient echo T2-weighted images of DC-MRI. The fibrosis grades of different segments were compared using the Kruskal-Wallis test followed by post-hoc analysis to establish the segment-by-segment differences. The incidences of two pre-established morphologic signs of cirrhosis were also compared with each other between the two groups of patients. There were significant intersegmental differences in fibrosis grades of the C-viral group (p = 0.005), and the CL showed lower fibrosis grades as compared with the grades of the RL and MS, whereas all lobes were similarly affected in the B-viral group (p = 0.221). The presence of a right posterior hepatic notch was significantly higher in the patients with intersegmental differences of fibrosis between the RL and the CL (19 out of 25, 76%) than those without such differences (6 out of 32, 19%) (p < 0.001). An expanded gallbladder fossa showed no significant relationship (p = 0.327) with the segmental difference of the fibrosis grades between the LS and the MS. The relative lack of fibrosis in the CL with more advanced fibrosis in the RL can be a distinguishing feature to differentiate chronic C-viral hepatitis from chronic B-viral hepatitis and this is closely related to the presence of a right posterior hepatic notch.

  14. A New Alkaline pH-Adjusted Medium Enhances Detection of β-Hemolytic Streptococci by Minimizing Bacterial Interference Due to Streptococcus salivarius

    Science.gov (United States)

    Dierksen, Karen P.; Ragland, Nancy L.; Tagg, John R.

    2000-01-01

    A new selective medium (CNA-P) that reduces or eliminates the inhibitory activity of bacteriocin-producing Streptococcus salivarius against β-hemolytic streptococci has been developed and compared with sheep blood agar (SBA) for the sensitive detection of small numbers of β-hemolytic streptococci in clinical specimens. CNA-P has as its basis a commercial medium (Difco Columbia CNA agar) supplemented with 5% (vol/vol) sheep blood, and the CNA is further modified by addition of 100 mM PIPES buffer [piperazine-N,N′-bis(2-ethanesulfonic acid)] (pH 7.5) to maintain cultures at an alkaline pH during incubation. CNA-P was shown to inhibit the production and/or release of four different types of S. salivarius bacteriocins or bacteriocin-like inhibitory molecules. The efficacies of CNA-P and SBA for detection of β-hemolytic streptococci in 1,352 pharyngeal samples from 376 children were compared. The β-hemolytic streptococcal isolates recovered from the samples included 314 group A (S. pyogenes), 61 group G, 33 group B, and 5 group C streptococci. Of 314 samples that yielded S. pyogenes, 300 were positive on CNA-P (96%) and 264 (86%) were positive on SBA. A significantly greater number of S. pyogenes isolates from these samples were recovered only on CNA-P (50 of 314) compared with the number of isolates recovered only on SBA (14 of 314). In addition, the degree of positivity, a measure of the total numbers of S. pyogenes isolates on the plate, was significantly higher on CNA-P than on SBA (2.40 versus 2.07; P < 0.001). Interestingly, CNA-P was also found to enhance the hemolytic activity of streptolysin O, allowing detection of streptolysin S-deficient S. pyogenes strains which might otherwise go undetected on SBA and other isolation media. PMID:10655361

  15. Anthropogenic global warming threatens world cultural heritage

    Science.gov (United States)

    Cazenave, Anny

    2014-05-01

    Numerous cultural sites of the United Nations Educational, Scientific and Cultural Organization (UNESCO) world cultural Heritage are located in low-lying coastal regions. Because of anthropogenic global warming and induced sea level rise, many of these sites will be partially or totally flooded in the coming centuries/millennia. This is shown in a recent study by Marzeion and Levermann (2014 Environ. Res. Lett. 9 034001). Projecting future sea level rise and associated regional variability, these authors investigate which sites will be at risk. Because UNESCO cultural sites represent the common heritage of human beings and reflect the Earth and humanity history, they need to be protected for future generations.

  16. Anthropogenic global warming threatens world cultural heritage

    OpenAIRE

    A. Cazenave

    2014-01-01

    1748-9326 Numerous cultural sites of the United Nations Educational, Scientific and Cultural Organization (UNESCO) world cultural Heritage are located in low-lying coastal regions. Because of anthropogenic global warming and induced sea level rise, many of these sites will be partially or totally flooded in the coming centuries/millennia. This is shown in a recent study by Marzeion and Levermann (2014 Environ. Res. Lett. 9 [http://dx.doi.org/10.1088/1748-9326/9/3/034001] 034001 ). Projecti...

  17. SU-E-T-231: Measurements of Gold Nanoparticle-Mediated Proton Dose Enhancement Due to Particle-Induced X-Ray Emission and Activation Products Using Radiochromic Films and CdTe Detector

    Energy Technology Data Exchange (ETDEWEB)

    Cho, J; Cho, S [Dept. of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX (United States); Manohar, N [Dept. of Radiation Physics, UT MD Anderson Cancer Center, Houston, TX (United States); Medical Physics Program, Georgia Institute of Technology, Atlanta, GA (Georgia); Krishnan, S [Dept. of Radiation Oncology, UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: There have been several reports of enhanced cell-killing and tumor regression when tumor cells and mouse tumors were loaded with gold nanoparticles (GNPs) prior to proton irradiation. While particle-induced xray emission (PIXE), Auger electrons, secondary electrons, free radicals, and biological effects have been suggested as potential mechanisms responsible for the observed GNP-mediated dose enhancement/radiosensitization, there is a lack of quantitative analysis regarding the contribution from each mechanism. Here, we report our experimental effort to quantify some of these effects. Methods: 5-cm-long cylindrical plastic vials were filled with 1.8 mL of either water or water mixed with cylindrical GNPs at the same gold concentration (0.3 mg Au/g) as used in previous animal studies. A piece of EBT2 radiochromic film (30-µm active-layer sandwiched between 80/175-µm outer-layers) was inserted along the long axis of each vial and used to measure dose enhancement due to PIXE from GNPs. Vials were placed at center-of-modulation (COM) and 3-cm up-/down-stream from COM and irradiated with 5 different doses (2–10 Gy) using 10-cm-SOBP 160-MeV protons. After irradiation, films were cleaned and read to determine the delivered dose. A vial containing spherical GNPs (20 mg Au/g) was also irradiated, and gamma-rays from activation products were measured using a cadmium-telluride (CdTe) detector. Results: Film measurements showed no significant dose enhancement beyond the experimental uncertainty (∼2%). There was a detectable activation product from GNPs, but it appeared to contribute to dose enhancement minimally (<0.01%). Conclusion: Considering the composition of EBT2 film, it can be inferred that gold characteristic x-rays from PIXE and their secondary electrons make insignificant contribution to dose enhancement. The current investigation also suggests negligible dose enhancement due to activation products. Thus, previously-reported GNP-mediated proton dose

  18. Anthropogenic disturbances and status of forest and wildlife in the dry deciduous forests of Chhattisgarh state in India

    Institute of Scientific and Technical Information of China (English)

    Chandra Prakash Kala; Yogesh Dubey

    2012-01-01

    Abstract:The advent of modern forces and the changes in socioeconomic patterns of forest dwellers have increased the pressures on the forests.In order to mitigate such pressures and also to protect the forests and wildlife the model of protected aress networks has shifted and enhanced such pressures in the unprotected natural forests due to several reasons.Being a low profile category of protected status and continuous human settlements,the present study highlights the case of dry deciduous forests of Sarguja district of Chhattisgarh state of India.The major objectives of this study were to quantify the status of forests and wildlife and also to determine the extent of anthropogenic disturbances faced by the dry deciduous forests of central India.Transect and silent drive count methods were used for sampling wildlife and quadrat method was used for sampling vegetation.Besides,the local uses of various forest produces were also studied in view of understanding the people dependency on forests.The forest vegetation,in the study area,was predominated by Shorea robusta,which had Madhuca indica,Diospyrus melanoxylon and Buchnania lanzan as the major companion species.The forest had either the high girth class mature tree species or the saplings.The low vegetation cover and density were due to the high anthropogenic pressures mainly in the form of heavy livestock grazing and collection of ethnobotanically important species.The study though reveals that the area is not rich in wildlife and the forest is fragmented,the area still supports some important species,which include many rare and endangered plants and animals.The findings of this study have been discussed in view of the management and conservation of the forest and wildlife in the dry deciduous forests.

  19. Anthropogenic carbon in the East Greenland Current

    Science.gov (United States)

    Jutterström, Sara; Jeansson, Emil

    2008-07-01

    Sections of dissolved inorganic anthropogenic carbon ( CTanthro) based on 2002 data in the East Greenland Current (EGC) are presented. The CTanthro has been estimated using a model based on optimum multiparameter analysis with predefined source water types. Values of CTanthro have been assigned to the source water types through age estimations based on the transit time distribution (TTD) technique. The validity of this approach is discussed and compared to other methods. The results indicated that the EGC had rather high levels of CTanthro in the whole water column, and the anthropogenic signal of the different source areas were detected along the southward transit. We estimated an annual transport of CTanthro with the Denmark Strait overflow ( σθ > 27.8 kg m -3) of ∼0.036 ± 0.005 Gt C y -1. The mean CTanthro concentration in this density range was ∼30 μmol kg -1. The main contribution was from Atlantic derived waters, the Polar Intermediate Water and the Greenland Sea Arctic Intermediate Water.

  20. Evaluation of anthropogenic urban soils. Final report; Bewertung anthropogener Stadtboeden. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Blume, H.P.; Schleuss, U. [eds.

    1997-12-31

    The research project `Evaluation of Anthropogenic Urban Soils` was subsidized by the German Federal Ministry of Education, Science, Research and Technology and adviced by the working group `Stadtboeden` of the German Society of Soil Science. It was realized as a cooperation between the universities of Berlin (TU), Halle-Wittenberg, Hohenheim, Kiel and Rostock and had three objectives: - to characterize soils developed from anthropogenic substratums (`urban soils`), - to figure out distribution patterns of such soils and - to verify whether urban soils could be evaluated according to their filtering and habitat function in the same way as soils developed from natural parent material. Evaluation methods based on easily obtainable field data had to be adapted to `urban soils` respectively developed anew. For that reason some typical soils of anthropogenic lithogenesis had to be examined between 1993 and 1996 both on their importance as habitats for plants and soil organisms and on their filtering, buffering and transforming capacities for organic and inorganic pollutants. Accordingly representative `urban soils` were gathered in the towns of Berlin, Eckernfoerde, Essen, Halle, Kiel, Rostock and Stuttgart; these soils had developed from technogenic substratums (brick and mortar debris, municipal waste, ashes, slag, sludge) and redeposited alkaline resp. acidic natural substratums (mud, coal mine and coking plant deposits). Some of the soils were influenced by ground water, and all soils developed from the same kind of parent material belonged to different stages of development. (orig./SR) [Deutsch] Ziele des vom BMBF gefoerderten und vom Arbeitskreis Stadtboeden der Deutschen Bodenkundlichen Gesellschaft beratenen Verbundprojektes `Bewertung anthropogener Stadtboeden` waren die Charakterisierung von Boeden anthropogener Substrate, die exemplarische Ermittlung des Verteilungsmusters derartiger Boeden und die Pruefung, inwieweit sie sich aehnlich den Boeden natuerlicher

  1. Do Anthropogenic Dark Earths Occur in the Interior of Borneo? Some Initial Observations from East Kalimantan

    OpenAIRE

    Meine van Noordwijk; Eva Wollenberg; Kuyper, Thomas W.; Godwin Limberg; Bernard Sellato; Puri, Rajindra K.; Imam Basuki; Laura German; Douglas Sheil

    2012-01-01

    Anthropogenic soils of the Amazon Basin (Terra Preta, Terra Mulata) reveal that pre-Colombian peoples made lasting improvements in the agricultural potential of nutrient-poor soils. Some have argued that applying similar techniques could improve agriculture over much of the humid tropics, enhancing local livelihoods and food security, while also sequestering large quantities of carbon to mitigate climate change. Here, we present preliminary evidence f...

  2. Spatial resolution of subsurface anthropogenic heat fluxes in cities

    Science.gov (United States)

    Benz, Susanne; Bayer, Peter; Menberg, Kathrin; Blum, Philipp

    2015-04-01

    Urban heat islands in the subsurface contain large quantities of energy in the form of elevated groundwater temperatures caused by anthropogenic heat fluxes (AHFS) into the subsurface. Hence, the objective of this study is to exemplarily quantify these AHFS and the generated thermal powers in two German cities, Karlsruhe and Cologne. A two-dimensional (2D) statistical analytical model of the vertical subsurface anthropogenic heat fluxes across the unsaturated zone was developed. The model consists of a so-called Local Monte Carlo approach that introduces a spatial representation of the following sources of AHFS: (1) elevated ground surface temperatures, (2) basements, (3) sewage systems, (4) sewage leakage, (5) subway tunnels, and (6) district heating networks. The results show that district heating networks induce the largest local AHFS with values larger than 60 W/m2 and one order of magnitude higher than the other evaluated heat sources. Only sewage pipes and basements reaching into the groundwater cause equally high heat fluxes, with maximal values of 40.37 W/m2 and 13.60 W/m2, respectively. While dominating locally, the district heating network is rather insignificant for the citywide energy budget in both urban subsurfaces. Heat from buildings (1.51 ± 1.36 PJ/a in Karlsruhe; 0.31 ± 0.14 PJ/a in Cologne) and elevated GST (0.34 ± 0.10 PJ/a in Karlsruhe; 0.42 ± 0.13 PJ/a in Cologne) are dominant contributors to the anthropogenic thermal power of the urban aquifer. In Karlsruhe, buildings are the source of 70% of the annual heat transported into the groundwater, which is mainly caused by basements reaching into the groundwater. A variance analysis confirms these findings: basement depth is the most influential factor to citywide thermal power in the studied cities with high groundwater levels. The spatial distribution of fluxes, however, is mostly influenced by the prevailing thermal gradient across the unsaturated zone. A relatively cold groundwater

  3. Oxidation of elemental Hg in anthropogenic and marine airmasses

    Directory of Open Access Journals (Sweden)

    H. Timonen

    2013-03-01

    Full Text Available Mercury (Hg is a neurotoxin that bioaccumulates in the food chain. Mercury is emitted to the atmosphere primarily in its elemental form, which has a long lifetime allowing global transport. It is known that atmospheric oxidation of gaseous elemental mercury (GEM generates reactive gaseous mercury (RGM which plays an important role in the atmospheric mercury cycle by enhancing the rate of mercury deposition to ecosystems. However, the primary GEM oxidants, and the chemical composition of RGM are poorly known. Using speciated mercury measurements conducted at the Mt. Bachelor Observatory since 2005 we present two previously unidentified sources of RGM to the free troposphere (FT. Firstly, we observed elevated RGM concentrations, large RGM/GEM-ratios, and anti-correlation between RGM and GEM during Asian long-rang transport events, demonstrating that RGM is formed from GEM by in-situ oxidation in some anthropogenic pollution plumes in the FT. During the Asian pollution events the measured RGM/GEM-enhancement ratios reached peak values, up to ~0.20, which are significantly larger than ratios typically measured (RGM/GEM −3, high RGM/GEM-ratios (up to 1, and very low ozone levels during these events provide observational evidence indicating significant GEM oxidation in the lower FT in some conditions.

  4. Pravcice Rock Arch (Bohemian Switzerland National Park, Czech Republic) deterioration due to natural and anthropogenic weathering

    Czech Academy of Sciences Publication Activity Database

    Vařilová, Z.; Přikryl, R.; Cílek, Václav

    2011-01-01

    Roč. 63, 7/8 (2011), s. 1861-1878. ISSN 1866-6280 R&D Projects: GA ČR GA205/08/0676 Institutional research plan: CEZ:AV0Z30130516 Keywords : Upper Cretaceous sandstone * rock arch * Bohemian Cretaceous basin * weathering processes * mineralogy of efflorescence * water soluble salts chemistry Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.059, year: 2011

  5. Mapping 1995 global anthropogenic emissions of mercury

    Science.gov (United States)

    Pacyna, Jozef M.; Pacyna, Elisabeth G.; Steenhuisen, Frits; Wilson, Simon

    This paper presents maps of anthropogenic Hg emissions worldwide within a 1°×1° latitude/longitude grid system in 1995. As such, the paper is designed for modelers simulating the Hg transport within air masses and Hg deposition to aquatic and terrestrial ecosystems. Maps of total Hg emissions and its three main chemical species: elemental gaseous Hg, divalent gaseous Hg, and particle-associated Hg are presented. The main emissions occur in southeast Asia (particularly in China), South Africa, Central and Eastern Europe, and the Eastern United States. These are the regions where coal combustion is the main source of electricity and heat production. Waste incineration adds to these emissions in the Eastern United States. Emissions of total Hg and its three species are quite similar in terms of their (global) spatial distributions. They reflect the worldwide distribution of coal consumption in large power plants, industrial burners, and small combustion units, such as residential and commercial furnaces.

  6. Predicting Anthropogenic Noise Contributions to US Waters.

    Science.gov (United States)

    Gedamke, Jason; Ferguson, Megan; Harrison, Jolie; Hatch, Leila; Henderson, Laurel; Porter, Michael B; Southall, Brandon L; Van Parijs, Sofie

    2016-01-01

    To increase understanding of the potential effects of chronic underwater noise in US waters, the National Oceanic and Atmospheric Administration (NOAA) organized two working groups in 2011, collectively called "CetSound," to develop tools to map the density and distribution of cetaceans (CetMap) and predict the contribution of human activities to underwater noise (SoundMap). The SoundMap effort utilized data on density, distribution, acoustic signatures of dominant noise sources, and environmental descriptors to map estimated temporal, spatial, and spectral contributions to background noise. These predicted soundscapes are an initial step toward assessing chronic anthropogenic noise impacts on the ocean's varied acoustic habitats and the animals utilizing them. PMID:26610977

  7. Anthropogenic signals in Iranian extreme temperature indices

    Science.gov (United States)

    Balling, Robert C.; Kiany, Mohammad Sadegh Keikhosravi; Roy, Shouraseni Sen

    2016-03-01

    We analyzed spatial and temporal patterns in temperature extremes from 31 stations located throughout Iran for the period 1961 to 2010. As with many other parts of the globe, we found that the number of days (a) with high maximum temperatures was rising, (b) with high minimum temperatures was rising, and (c) with low minimum temperatures was declining; all of these trends were statistically significant at the 0.05 level of confidence. Population records from 1956 to 2011 at the station locations allowed us to reveal that the rate of human population growth was positively related to the increase in the number of days with high maximum temperatures and negatively related to days with low maximum temperatures. Our research shows a number of identifiable anthropogenic signals in the temperature records from Iran, but unlike most other studies, the signals are stronger with indices related to maximum, not minimum, temperatures.

  8. All-optical control in metal nanocomposites due to a reversible transition between local field enhancement and local field depression upon irradiation by ultrashort control-pulses of light

    Science.gov (United States)

    Im, Song-Jin; Ho, Gum-Song

    2014-04-01

    We theoretically study the non-perturbative effective nonlinear responses of metal nanocomposites based on the intrinsic third-order nonlinear response of metal nanoparticles. The large intrinsic third-order nonlinear susceptibility of metal nanoparticles and irradiation by an ultrashort control pulse of light with a sufficiently high peak intensity and moderate fluence can induce a local field depression and saturated plasmon bleaching in the metal nanoparticles. If the control pulse is on, the metal nanocomposites behave like a dielectric due to the local field depression, while if the control pulse is off, they behave like a metal, showing a high absorption due to the local field enhancement at the plasmon resonance. This phenomenon can be applied to the ultrafast and remote control of light in metal nanocomposites.

  9. All-optical control in metal nanocomposites due to a reversible transition between the local-field-enhancement and a local-field-depression upon irradiation by ultrashort control-pulses of light

    CERN Document Server

    Im, Song-Jin

    2014-01-01

    We theoretically study on non-perturbative effective nonlinear responses of metal nanocomposites based on the intrinsic third-order nonlinear response of metal nanoparticles. The large intrinsic third-order nonlinear susceptibility of metal nanoparticles and an irradiation by ultrashort control pulse of light with a sufficiently high peak intensity and moderate fluence can induce a local-field-depression and a saturated plasmon-bleaching in metal nanoparticles. If the control pulse is on, the metal nanocomposites can behave like a dielectric due to the local-field-depression, while if the control pulse is off, the metal nanocomposites can behave like a metal showing a high absorption due to the local-field-enhancement at the plasmon-resonance. This phenomenon can be applied to an ultrafast and remote control of light in metal nanocomposites.

  10. All-optical control in metal nanocomposites due to a reversible transition between local field enhancement and local field depression upon irradiation by ultrashort control-pulses of light

    International Nuclear Information System (INIS)

    We theoretically study the non-perturbative effective nonlinear responses of metal nanocomposites based on the intrinsic third-order nonlinear response of metal nanoparticles. The large intrinsic third-order nonlinear susceptibility of metal nanoparticles and irradiation by an ultrashort control pulse of light with a sufficiently high peak intensity and moderate fluence can induce a local field depression and saturated plasmon bleaching in the metal nanoparticles. If the control pulse is on, the metal nanocomposites behave like a dielectric due to the local field depression, while if the control pulse is off, they behave like a metal, showing a high absorption due to the local field enhancement at the plasmon resonance. This phenomenon can be applied to the ultrafast and remote control of light in metal nanocomposites. (paper)

  11. Potential Impact of South Asian Anthropogenic Aerosols on Northern Hemisphere Climate

    Science.gov (United States)

    Bollasina, M. A.; Ming, Y.; Ramaswamy, V.

    2014-12-01

    South Asia has one of the world's highest aerosol loading due to the dramatic increase of anthropogenic emissions from the 1950s associated with rapid urbanization and population growth. The possible large-scale impact of the late 20th century increase of South Asian aerosol emissions on climate away from the source regions was studied by means of historical ensemble experiments with a state-of-the-art coupled climate model with fully interactive aerosols and a representation of both direct and indirect aerosol effects. The key characteristics of the northern hemisphere responses are examined separately for winter and summer, and show that regional aerosols induce significant planetary-scale teleconnection patterns. In both seasons, the large-scale aerosol imprint originates from substantial changes in the regional precipitation distribution. During the winter, in response to anomalous surface cooling in the northern Indian Ocean, aerosols cause a westward shift of convection over the eastern Indian Ocean and compensating subsidence to the west and over the Maritime continent. During the summer, aerosols are collocated with rainfall, and cause a widespread drying over South Asia mostly by indirect effects. In both cases, the impact of the regional diabatic heating anomaly propagates remotely by exciting a northern hemisphere wave-train which, enhanced by regional feedbacks, leads to remarkable changes in near-surface climate, including circulation and temperature, over Eurasia, the northern Pacific and North America. Depending on the region, the induced anomalies may have opposite signs between the two seasons, and may thus contribute to reinforcing or dampening those due greenhouse gases. These results underscore the potential influence of Asian aerosols on global climate, which is a compelling problem as regional aerosol loading will continue to be large in the coming decades.

  12. Methane hydrate stability and anthropogenic climate change

    Directory of Open Access Journals (Sweden)

    D. Archer

    2007-04-01

    Full Text Available Methane frozen into hydrate makes up a large reservoir of potentially volatile carbon below the sea floor and associated with permafrost soils. This reservoir intuitively seems precarious, because hydrate ice floats in water, and melts at Earth surface conditions. The hydrate reservoir is so large that if 10% of the methane were released to the atmosphere within a few years, it would have an impact on the Earth's radiation budget equivalent to a factor of 10 increase in atmospheric CO2.

    Hydrates are releasing methane to the atmosphere today in response to anthropogenic warming, for example along the Arctic coastline of Siberia. However most of the hydrates are located at depths in soils and ocean sediments where anthropogenic warming and any possible methane release will take place over time scales of millennia. Individual catastrophic releases like landslides and pockmark explosions are too small to reach a sizable fraction of the hydrates. The carbon isotopic excursion at the end of the Paleocene has been interpreted as the release of thousands of Gton C, possibly from hydrates, but the time scale of the release appears to have been thousands of years, chronic rather than catastrophic.

    The potential climate impact in the coming century from hydrate methane release is speculative but could be comparable to climate feedbacks from the terrestrial biosphere and from peat, significant but not catastrophic. On geologic timescales, it is conceivable that hydrates could release much carbon to the atmosphere/ocean system as we do by fossil fuel combustion.

  13. Methane hydrate stability and anthropogenic climate change

    Directory of Open Access Journals (Sweden)

    D. Archer

    2007-07-01

    Full Text Available Methane frozen into hydrate makes up a large reservoir of potentially volatile carbon below the sea floor and associated with permafrost soils. This reservoir intuitively seems precarious, because hydrate ice floats in water, and melts at Earth surface conditions. The hydrate reservoir is so large that if 10% of the methane were released to the atmosphere within a few years, it would have an impact on the Earth's radiation budget equivalent to a factor of 10 increase in atmospheric CO2.

    Hydrates are releasing methane to the atmosphere today in response to anthropogenic warming, for example along the Arctic coastline of Siberia. However most of the hydrates are located at depths in soils and ocean sediments where anthropogenic warming and any possible methane release will take place over time scales of millennia. Individual catastrophic releases like landslides and pockmark explosions are too small to reach a sizable fraction of the hydrates. The carbon isotopic excursion at the end of the Paleocene has been interpreted as the release of thousands of Gton C, possibly from hydrates, but the time scale of the release appears to have been thousands of years, chronic rather than catastrophic.

    The potential climate impact in the coming century from hydrate methane release is speculative but could be comparable to climate feedbacks from the terrestrial biosphere and from peat, significant but not catastrophic. On geologic timescales, it is conceivable that hydrates could release as much carbon to the atmosphere/ocean system as we do by fossil fuel combustion.

  14. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes.

    Directory of Open Access Journals (Sweden)

    Esther H D Carlitz

    Full Text Available Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates, compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129 = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178 = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC. With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88 = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species.

  15. Stochastic memory: memory enhancement due to noise

    OpenAIRE

    Stotland, Alexander; Di Ventra, Massimiliano

    2011-01-01

    There are certain classes of resistors, capacitors and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here, we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by $\\mathrm{TiO_2}$ thin films sandwiched between...

  16. South Caspian Pliocene-Anthropogenic basin (summary of existing views)

    Science.gov (United States)

    Amrakhov, Rashad; Shiraliyeva, Sevinj; Kerimova, Nailya

    2016-04-01

    On the basis of long-time integrated sedimentology, paleogeographic and structural - formation studies covering Pliocene-Anthropogenic sediments of South Caspian Basin (SCB) and design of structural - formation, paleogeographic and catagenetic models applying geophysical studies in the region, the author has interred rift nature on this basin during Pliocene-Anthropogenic stage of its evolution. It is assumed that SCB is intercontinental with absence of continental crust. Evolution of SCR started from Miocene, continental stage of development Lesser and Great Caucasus and Kopetdag. At initial stage of South Caspian rift-graben evolution the crystal uplift of Caucasus, Kopetdag and Talysh organic system took place. Extension forces within their borders caused collapse of central part of South Caspian block. We assumed that at later stage folded blocks of Lesser Caucasus and Talysh on the other hand Alborz and Kopetdagh on the other were moving apart. As a result of these riftogene processes the contemporary structure of SCB Antropogene was formed. Starting from Miocene, subsidence of central part of SCB and later movements of folded blocks of Great and Lesser Caucasus, Talysh and Elbrus occurred along Western Caspian, Sangachal - Ogurcghy deep faults and Turkmenistan thrust. During rift generation within SCB, magmatic troughs emerged in the rift zone - South Absheron, Lower Kura. Enzaly and Western Turkmenistan. Structural-formation studies with application of geophysical data acquired in the region, allow assuming that massive Godina can be considered as interrift horst with large gravity anomaly. Its generation relates to Miocene-Pliocene ages and was formed due to South Caspian riftogenesis. The following are sedimentologic evidences of South Caspian rift basin: a) Avalanche sedimentation and development of large thickness (2.5-3 km/106 years) even within border of Lower Pliocene (Productive Series); b) Morphology of Lower Pliocene molasses formation covering 600

  17. Source identification of VOCs at an urban site of western India: Effect of marathon events and anthropogenic emissions

    Science.gov (United States)

    Sahu, L. K.; Yadav, Ravi; Pal, Devendra

    2016-03-01

    Ambient volatile organic compounds (VOCs) were measured using a high-resolution proton transfer reaction-time of flight-mass spectrometer at an urban site of Ahmedabad in India during the winter season in 2014. Mixing ratios of VOCs show large diurnal and day-to-day variations. Although strongly influenced by local emissions, periods of higher VOCs were observed during transport from the polluted Indo-Gangetic Plains than those from the cleaner Thar Desert. However with different rates, VOCs decreased exponentially with increasing wind speed. Relative abundance of methanol varied with weather conditions contributing highest and lowest under fog and clear-sky conditions, respectively. Among the compounds reported here, oxygenated VOCs (OVOCs) contribute to a large fraction (67-85%) with methanol being most abundant (40-58%). In spite of predominant vehicular emissions, diurnal distribution and emission ratios (ERs) of several VOCs indicate the role of biogenic and secondary sources. The ratios of isoprene/benzene and OVOCs/benzene show significant enhancements during daytime suggesting their contributions from biogenic and secondary sources. During marathon and cyclothon events, mixing ratios of VOCs were 2-10 times higher compared to a normal Sunday. The ERs of VOCs estimated using the nighttime data on marathon day are well within the range of values reported for several megacities of the world. The average contributions of primary anthropogenic sources to acetaldehyde, acetone, and isoprene were 44 ± 06%, 45 ± 07%, and 63 ± 12%, respectively. During cloudy condition, the increase in anthropogenic contribution to acetaldehyde (~10%), acetone (9%) and isoprene (30%) is due to reduction in biogenic emissions and secondary formation of these VOCs.

  18. Time series monitoring of water quality and microalgal diversity in a tropical bay under intense anthropogenic interference (SW coast of the Bay of Bengal, India)

    Energy Technology Data Exchange (ETDEWEB)

    Shaik, Aziz ur Rahman [CSIR — National Institute of Oceanography, Regional Centre, 176 Lawson' s Bay Colony, Visakhapatnam, AP 530017 (India); Biswas, Haimanti, E-mail: haimanti.biswas@nio.org [CSIR — National Institute of Oceanography, Regional Centre, 176 Lawson' s Bay Colony, Visakhapatnam, AP 530017 (India); Reddy, N.P.C.; Srinivasa Rao, V. [CSIR — National Institute of Oceanography, Regional Centre, 176 Lawson' s Bay Colony, Visakhapatnam, AP 530017 (India); Bharathi, M.D. [Present address: ICMAM Project Directorate, 2nd Floor, NIOT Campus, Velacherry-Tambaram Main Road, Pallikkaranai, Chennai 600100 (India); Subbaiah, Ch.V. [CSIR — National Institute of Oceanography, Regional Centre, 176 Lawson' s Bay Colony, Visakhapatnam, AP 530017 (India)

    2015-11-15

    In recent decades, material fluxes to coastal waters from various land based anthropogenic activities have significantly been enhanced around the globe which can considerably impact the coastal water quality and ecosystem health. Hence, there is a critical need to understand the links between anthropogenic activities in watersheds and its health. Kakinada Bay is situated at the SW part of the Bay of Bengal, near to the second largest mangrove cover in India with several fertilizer industries along its bank and could be highly vulnerable to different types of pollutants. However, virtually, no data is available so far reporting its physicochemical status and microalgal diversity at this bay. In order to fill this gap, we conducted three time series observations at a fixed station during January, December and June 2012, at this bay measuring more than 15 physical, chemical and biological parameters in every 3 h over a period of 36 h in both surface (0 m) and subsurface (4.5 m) waters. Our results clearly depict a strong seasonality between three sampling months; however, any abnormal values of nutrients, biological oxygen demand or dissolved oxygen level was not observed. A Skeletonema costatum bloom was observed in December which was probably influenced by low saline, high turbid and high Si input through the river discharge. Otherwise, smaller diatoms like Thalassiosira decipiens, Thalassiothrix frauenfeldii, and Thalassionema nitzschioides dominated the bay. It is likely that the material loading can be high at the point sources due to intense anthropogenic activities, however, gets diluted with biological, chemical and physical processes in the offshore waters. - Highlights: • No signature of enormous nutrient loading was observed over the diel cycle • Dissolved oxygen and BOD concentrations did not show any exceptional trend • Diatoms dominated more than 90% of the total phytoplankton communities • A Skeletonema Costatum (a centric diatom) bloom was

  19. Time series monitoring of water quality and microalgal diversity in a tropical bay under intense anthropogenic interference (SW coast of the Bay of Bengal, India)

    International Nuclear Information System (INIS)

    In recent decades, material fluxes to coastal waters from various land based anthropogenic activities have significantly been enhanced around the globe which can considerably impact the coastal water quality and ecosystem health. Hence, there is a critical need to understand the links between anthropogenic activities in watersheds and its health. Kakinada Bay is situated at the SW part of the Bay of Bengal, near to the second largest mangrove cover in India with several fertilizer industries along its bank and could be highly vulnerable to different types of pollutants. However, virtually, no data is available so far reporting its physicochemical status and microalgal diversity at this bay. In order to fill this gap, we conducted three time series observations at a fixed station during January, December and June 2012, at this bay measuring more than 15 physical, chemical and biological parameters in every 3 h over a period of 36 h in both surface (0 m) and subsurface (4.5 m) waters. Our results clearly depict a strong seasonality between three sampling months; however, any abnormal values of nutrients, biological oxygen demand or dissolved oxygen level was not observed. A Skeletonema costatum bloom was observed in December which was probably influenced by low saline, high turbid and high Si input through the river discharge. Otherwise, smaller diatoms like Thalassiosira decipiens, Thalassiothrix frauenfeldii, and Thalassionema nitzschioides dominated the bay. It is likely that the material loading can be high at the point sources due to intense anthropogenic activities, however, gets diluted with biological, chemical and physical processes in the offshore waters. - Highlights: • No signature of enormous nutrient loading was observed over the diel cycle • Dissolved oxygen and BOD concentrations did not show any exceptional trend • Diatoms dominated more than 90% of the total phytoplankton communities • A Skeletonema Costatum (a centric diatom) bloom was

  20. Impact of Chinese anthropogenic emissions on submicrometer aerosol concentration at Mt. Tateyama, Japan

    Directory of Open Access Journals (Sweden)

    H. Iida

    2009-12-01

    Full Text Available Rapid Asian economic development might engender secondary impacts of atmospheric aerosol particles over the western Pacific after conversion of gaseous pollutants such as SO2. To elucidate changes in aerosol concentrations in leeward areas undergoing remarkable industrialization, the number-size distributions of submicrometer (0.3–1.0 μm aerosols were measured at Murododaira (36.6° N, 137.6° E, 2450 m a.s.l. on the western flank of Mount Tateyama in central Japan during January 1999–February 2009. Nighttime data obtained from 2400 to 0500 were used to analyze free-tropospheric aerosol concentration. Monthly average volume concentrations were calculated for months with >50% daily data coverage. Volume concentrations of submicrometer aerosols were high in spring to early summer and low in winter. Significant increasing trends at 95% confidence levels were found for volume concentrations in winter–spring. Simulated monthly anthropogenic aerosol concentrations at Mt. Tateyama from results of regional aerosol modeling with emission inventory up to 2005 showed seasonal variation and winter–spring increasing trends similar to those of observed aerosol concentration. According to the model analyses, the contribution of anthropogenic aerosol concentrations derived from China was high during winter–spring (60–80% of total anthropogenic aerosols at Mt. Tateyama. This accords with the increasing trend observed for winter–spring. Because SO42− is the dominant component of total anthropogenic aerosols, these results suggest that increasing anthropogenic emissions, especially for SO2, in China, engender enhancement of submicrometer-diameter aerosols over Japan during winter–spring.

  1. Simulated anthropogenic CO2 storage and acidification of the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    J. Palmiéri

    2015-02-01

    Full Text Available Constraints on the Mediterranean Sea's storage of anthropogenic CO2 are limited, coming only from data-based approaches that disagree by more than a factor of two. Here we simulate this marginal sea's anthropogenic carbon storage by applying a perturbation approach in a high-resolution regional model. Our model simulates that, between 1800 and 2001, basin-wide CO2 storage by the Mediterranean Sea has increased by 1.0 Pg C, a lower limit based on the model's weak deep-water ventilation, as revealed by evaluation with CFC-12. Furthermore, by testing a data-based approach (transit time distribution in our model, comparing simulated anthropogenic CO2 to values computed from simulated CFC-12 and physical variables, we conclude that the associated basin-wide storage of 1.7 Pg, published previously, must be an upper bound. Out of the total simulated storage of 1.0 Pg C, 75% comes from the air–sea flux into the Mediterranean Sea and 25% comes from net transport from the Atlantic across the Strait of Gibraltar. Sensitivity tests indicate that the Mediterranean Sea's higher total alkalinity, relative to the global-ocean mean, enhances the Mediterranean's total inventory of anthropogenic carbon by 10%. Yet the corresponding average anthropogenic change in surface pH does not differ significantly from the global-ocean average, despite higher total alkalinity. In Mediterranean deep waters, the pH change is estimated to be between −0.005 and −0.06 pH units.

  2. Marine fish assemblages as indicators of anthropogenic pressures:identifying sensitive metrics

    OpenAIRE

    Pires, Sofia Nunes Henriques Margarido

    2013-01-01

    Tese de doutoramento, Biologia (Biologia Marinha e Aquacultura), Universidade de Lisboa, Faculdade de Ciências, 2013 Worldwide concern about the environmental threats and need for sustainable development has led to increased efforts to understand and assess anthropogenic pressure effects. However, the development of indicators for marine ecosystems is still at an early stage, due to their high spatial and temporal complexity. Based on several structural and functional traits (guild approac...

  3. Rolling Out the Anthropogenic Aluminum Cycle: With Foci on Temporal, Geographical, and Emission Perspectives

    OpenAIRE

    Liu, Gang

    2013-01-01

    Anthropogenic metal cycles today confront three interconnected large challenges: an increasing global demand due to rising population and escalating industrialization and urbanization, a profound change of the global supply chain induced by globalization process, and growing pressures on climate change mitigation in a carbon constraint world. For example, the global demand for aluminum, the currently second most used metal worldwide, is anticipated to triple by 2050, by which time global gree...

  4. Effects of anthropogenic disturbance of Afromontane forest on butterflies (Lepidoptera, Nymphalidae) in Amani Nature Reserve, Tanzania.

    OpenAIRE

    Notø, Cecilie

    2014-01-01

    The majority of the world’s biological diversity is located in the tropics, where forest is an essential biome. A healthy web of biodiversity is the foundation for ecosystem services humans depend on but it is currently under severe pressure due to anthropogenic disturbances. The result is a fragmented landscape of primary forest, secondary forest, plantations and agroforest. Conservation efforts have traditionally focused on preserving primary forest, but research on the response of differen...

  5. Anthropogenic Cycles of Rare Earth Elements

    Science.gov (United States)

    Du, X.; Graedel, T. E.

    2009-12-01

    This research will develop quantitatively resolved anthropogenic cycles and in-use stocks for the rare earth metals specifically cerium, lanthanum and dysprosium in Japan, China, and the U.S. for the year of 2007. Rare earth elements (REE) is a group of 17 scare metals widely used in a growing number of emerging technologies and have been in high demand for emerging technologies as raw materials during past the three decades. New market participants from newly industrializing countries, primarily China, have had strong impacts on the demand of share. Consequently, the importance to sustain a reliable, steady, uninterrupted supply on global market triggered comprehensive research to recognize and understand the life cycles of rare earths. Moreover, because China plays a dominant role in mining production since 1990, it requires the assessment for the countries, which are almost completely dependent on imports from China with respect to rare earth resources. The study aims to analyze the flows and stocks of rare earth elements individually as elemental form in spite of their natural geological co-occurrence and mixed composition in applications. By applying the method of Material Flow Analysis (MFA) work has been done on evaluating current and historical flows of specific technologically significant materials, for example, copper, zinc, nickel, etc., determining the stocks available in different types of reservoirs (e.g., lithosphere, in-use) and the flows among the reservoirs, developing scenarios of possible futures of metal use, and assessing the environmental and policy implications of the results. Therefore, REE as a new target deserves inclusion because of its potential demand-supply conflict and importance to secure the competitive advantage of technical innovation in future. This work will generate a quantitatively resolved anthropogenic life cycle and in-use stocks for REE for the main target countries for a chosen year, 2007, providing flows and stocks from

  6. Damping of glacial-interglacial cycles from anthropogenic forcing

    CERN Document Server

    Haqq-Misra, Jacob

    2014-01-01

    Climate variability over the past million years shows a strong glacial-interglacial cycle of ~100,000 years as a combined result of Milankovitch orbital forcing and climatic resonance. It has been suggested that anthropogenic contributions to radiative forcing may extend the length of the present interglacial, but the effects of anthropogenic forcing on the periodicity of glacial-interglacial cycles has received little attention. Here I demonstrate that moderate anthropogenic forcing can act to damp this 100,000 year cycle and reduce climate variability from orbital forcing. Future changes in solar insolation alone will continue to drive a 100,000 year climate cycle over the next million years, but the presence of anthropogenic warming can force the climate into an ice-free state that only weakly responds to orbital forcing. Sufficiently strong anthropogenic forcing that eliminates the glacial-interglacial cycle may serve as an indication of an epoch transition from the Pleistocene to the Anthropocene.

  7. Assessing the observed impact of anthropogenic climate change

    Science.gov (United States)

    Hansen, Gerrit; Stone, Dáithí

    2016-05-01

    Impacts of recent regional changes in climate on natural and human systems are documented across the globe, yet studies explicitly linking these observations to anthropogenic forcing of the climate are scarce. Here we provide a systematic assessment of the role of anthropogenic climate change for the range of impacts of regional climate trends reported in the IPCC’s Fifth Assessment Report. We find that almost two-thirds of the impacts related to atmospheric and ocean temperature can be confidently attributed to anthropogenic forcing. In contrast, evidence connecting changes in precipitation and their respective impacts to human influence is still weak. Moreover, anthropogenic climate change has been a major influence for approximately three-quarters of the impacts observed on continental scales. Hence the effects of anthropogenic emissions can now be discerned not only globally, but also at more regional and local scales for a variety of natural and human systems.

  8. Diurnal tracking of anthropogenic CO2 emissions in the Los Angeles basin megacity during spring 2010

    Directory of Open Access Journals (Sweden)

    S. Newman

    2013-04-01

    Full Text Available Attributing observed CO2 variations to human or natural cause is critical to deducing and tracking emissions from observations. We have used in situ CO2, CO, and planetary boundary layer height (PBLH measurements recorded during the CalNex-LA (CARB et al., 2008 ground campaign of 15 May–15 June 2010, in Pasadena, CA, to deduce the diurnally varying anthropogenic component of observed CO2 in the megacity of Los Angeles (LA. This affordable and simple technique, validated by carbon isotope observations and WRF-STILT (Weather Research and Forecasting model – Stochastic Time-Inverted Lagrangian Transport model predictions, is shown to robustly attribute observed CO2 variation to anthropogenic or biogenic origin over the entire diurnal cycle. During CalNex-LA, local fossil fuel combustion contributed up to ~50% of the observed CO2 enhancement overnight, and ~100% of the enhancement near midday. This suggests that sufficiently accurate total column CO2 observations recorded near midday, such as those from the GOSAT or OCO-2 satellites, can potentially be used to track anthropogenic emissions from the LA megacity.

  9. Estimation of the Distribution of Global Anthropogenic Heat Flux

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The radiance lights data in 2006 from the National Oceanic and Atmospheric Administration Air Force Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) and authoritative energy data distributed by the United State Energy Information Administration were applied to estimate the global distribution of anthropogenic heat flux.A strong linear relationship was found to exist between the anthropogenic heat flux and the DMSP/OLS radiance data.On a global scale,the average value of anthropogenic heat flux is approximately 0.03 W m 2 and 0.10 W m 2 for global land area.The results indicate that global anthropogenic heat flux was geographically concentrated and distributed,fundamentally correlating to the economical activities.The anthropogenic heat flux concentrated in the economically developed areas including East Asia,Europe,and eastern North America.The anthropogenic heat flux in the concentrated regions,including the northeastern United States,Central Europe,United Kingdom,Japan,India,and East and South China is much larger than global average level,reaching a large enough value that could affect regional climate.In the center of the concentrated area,the anthropogenic heat flux density may exceed 100 W m 2,according to the results of the model.In developing areas,including South America,Central and North China,India,East Europe,and Middle East,the anthropogenic heat flux can reach a level of more than 10 W m 2 ;however,the anthropogenic heat flux in a vast area,including Africa,Central and North Asia,and South America,is low.With the development of global economy and urban agglomerations,the effect on climate of anthropogenic heat is essential for the research of climate change.

  10. CLANIMAE: Climatic and Anthropogenic Impacts on African Ecosystems

    Science.gov (United States)

    Verschuren, D.; André, L.; Mahy, G.; Cocquyt, C.; Plisnier, P.-D.; Gelorini, V.; Rumes, B.; Lebrun, J.; Bock, L.; Marchant, R.

    2009-04-01

    Global studies of historical land use focusing on the large-scale landscape change that can potentially affect global climate (via effects on surface albedo, aerosols, and the carbon cycle) have concluded that the impact of pre-colonial East African cultures on regional ecosystems was limited, due to very low mean population density. This contrasts with the paradigm in East African archaeology and paleoecology that the onset of anthropogenic deforestation started at least 2500 years ago, following the introduction of iron metallurgy by Bantu immigrants. This conflict highlights the present lack of real data on historical climate-environment-human interactions in East Africa, which are eminently relevant to sustainable natural resource management and biodiversity conservation in a future of continued population growth and global climate change. CLANIMAE responds to the urgent need of a correct long-term perspective to today's climate-environment-human interactions in East Africa, by reconstructing simultaneously the histories of past climate change and of vegetation and water-quality changes over the last 2500 years, through multi-disciplinary analysis of dated lake-sediment records. The climate reconstructions integrate information on biological, geochemical and sedimentological indicators of past changes in the water balance of the study lakes, which cover the climatological gradient from (sub-)humid western Uganda to semi-arid eastern Kenya. Reconstruction of past terrestrial vegetation dynamics is based on analyses of fossil plant pollen and phytoliths, plus the fossil spores of fungi associated with the excrements of large domestic animals as indicators of lake use by pastoralists. The evolution of water quality through time is reconstructed using silicon isotopes in diatom algae as proxy indicator for past phytoplankton productivity, and paleoecological analyses of fossil diatoms and aquatic macrophytes, following calibration of diatom and macrophyte species

  11. ANTHROPOGENIC PRESSURE ON FORESTS IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Ildiko\tIOAN

    2015-06-01

    Full Text Available Forests are one of the richest ecosystems in terms of biomass stock and this potential is augmented by a broad range of ecosystem services that contribute to human wellbeing by protecting air from pollution, soil from runoff, landscapes from flooding and landslides. This high economic and ecologic potential is well acknowledged, but in specific circumstances short terms gains resulting from the valuation of wood or from conversion of land to other uses are prevailing and create powerful incentives for overexploitation or deforestation. The anthropogenic pressure on forests was and continues to remain high at global level, although there are states where it was successfully controlled. Nevertheless, the forest cover is shrinking increasing the associated threats that result from the cancellation of the forests’ ecosystem services. Of particular importance in the current context is the reduction of forests’ carbon sequestration potential, which is of crucial importance in climate change mitigation. The patterns of unfavourable circumstances are analysed in order to outline the most important challenges of forest management in Romania, but also the impact of novel ecosystem service based economic tools that are aimed to strengthen the incentives for sustainable forest management and to avoid conversion of forests to other land use types.

  12. Increased threat of tropical cyclones and coastal flooding to New York City during the anthropogenic era.

    Science.gov (United States)

    Reed, Andra J; Mann, Michael E; Emanuel, Kerry A; Lin, Ning; Horton, Benjamin P; Kemp, Andrew C; Donnelly, Jeffrey P

    2015-10-13

    In a changing climate, future inundation of the United States' Atlantic coast will depend on both storm surges during tropical cyclones and the rising relative sea levels on which those surges occur. However, the observational record of tropical cyclones in the North Atlantic basin is too short (A.D. 1851 to present) to accurately assess long-term trends in storm activity. To overcome this limitation, we use proxy sea level records, and downscale three CMIP5 models to generate large synthetic tropical cyclone data sets for the North Atlantic basin; driving climate conditions span from A.D. 850 to A.D. 2005. We compare pre-anthropogenic era (A.D. 850-1800) and anthropogenic era (A.D.1970-2005) storm surge model results for New York City, exposing links between increased rates of sea level rise and storm flood heights. We find that mean flood heights increased by ∼1.24 m (due mainly to sea level rise) from ∼A.D. 850 to the anthropogenic era, a result that is significant at the 99% confidence level. Additionally, changes in tropical cyclone characteristics have led to increases in the extremes of the types of storms that create the largest storm surges for New York City. As a result, flood risk has greatly increased for the region; for example, the 500-y return period for a ∼2.25-m flood height during the pre-anthropogenic era has decreased to ∼24.4 y in the anthropogenic era. Our results indicate the impacts of climate change on coastal inundation, and call for advanced risk management strategies. PMID:26417111

  13. Atmospheric delivery of anthropogenic bioavailable iron from mineral dust to the ocean

    Science.gov (United States)

    Ito, A.; Shi, Z.

    2015-12-01

    Atmospheric deposition of anthropogenic soluble iron (Fe) to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. Here, we interactively combined laboratory kinetic experiments with global aerosol modeling to more accurately quantify anthropogenic soluble Fe due to air pollution. We firstly examined Fe dissolution kinetics of African dust samples at acidic pH values with and without ionic species commonly found in aerosol water (i.e., sulfate and oxalate). We then constructed a new empirical scheme for Fe release from mineral dust due to inorganic and organic anions in aerosol water, by using acidity as a master variable. We implemented this new scheme and applied an updated mineralogical emission database in a global atmospheric chemistry transport model to estimate the atmospheric concentration and deposition flux of soluble Fe under preindustrial and modern conditions. Our improved model successfully captured the inverse relationship of Fe solubility and total Fe loading measured over the North Atlantic Ocean. However, our modeled Fe solubility was significantly lower than that deduced from observations over the South Atlantic east downwind from the Patagonian dust source regions. Our modeled Fe solubility for dry deposition over the Atlantic is in good agreement the measurement, while that for wet deposition is significantly lower than the measurement. Our model results suggest that human activities contribute to about half of the soluble Fe supply to a significant portion of the oceans in the Northern Hemisphere, while their contribution to oceans in the high latitude remains highly uncertain

  14. Cytogenetic variability in pinus sylvestris L. populations experiencing anthropogenic influence

    Energy Technology Data Exchange (ETDEWEB)

    Oudalova, A.; Geras' kin, S.; Vasiliev, D.; Dikarev, V. [Russian Institute of Agricultural Radiology and Agroecology, Obninsk (Russian Federation)

    2004-07-01

    Techno-genic pollution has become one of the most significant ecological factors determining biosphere existence and development. An analysis of genetic consequences of the radiation accidents in the South Urals and Chernobyl has shown that mutation and recombination processes are considerably accelerated in plant and animal's populations experiencing techno-genic influence. This implies that there are complicated adaptation processes leading to changes in genetic structure of populations and increasing genetic load. Pinus sylvestris L. populations growing at the territory of the 'radon' Leningrad regional radioactive waste reprocessing enterprise and Sosnovy Bor town were monitored 6 years (1997-2002) by a set of cyto-genetical and morphological tests. Cytogenetic damage levels within intercalary meristem of needle as well as in root meristem of seedlings were found to significantly exceed corresponding controls. A higher radioresistance of the Scots pine seeds analyzed was demonstrated with an acute {gamma}-radiation that also revealed a selection process directed at an enhancement of repair efficiency and resulting in a shift of mean values of radioresistance in populations towards higher values. An enlargement of variance of studied cytogenetic parameters was found in the populations experiencing techno-genic influence. This indicates, with an account of phenomenon of the enhanced radioresistance, that there are processes of cyto-genetical adaptation in the investigated regions. An analysis of the structure of ecological-genetical variability was carried out with the purpose of separating two components in the inter-population variability - the first is engaged to the genetically determined variability of biological characteristics intrinsic for this species, and the second is responsible for the variability originating from anthropogenic contamination of the natural habitat. Changes of these two types of variability were studied in dependence on

  15. Towards a monitoring strategy to assess the anthropogenic signature of traffic derived pollution

    Science.gov (United States)

    Ojha, G.; Appel, E.; Magiera, T.; Wawer, M.

    2013-12-01

    Soil contamination along roadsides is one important factor of anthropogenic linear pollution source. In our present study we focus on typical traffic pollutants like heavy metals (HM), platinum group elements (PGEs), polycyclic aromatic hydrocarbons (PAHs) and investigate the use of magnetic parameters, in particular to discriminate the distribution of contaminants by surface runoff, splash-water and airborne transport. For monitoring we removed 10-15 cm of top soil at 1 m distance from the roadside edge and replaced it by 30 plastic boxes, and installed pillars at 1 m and 2 m distances to the roadside with samplers in different heights (ground, 0.5 m, 2 m) as well as 4 m long u-channels (surface and 2.5 cm above ground) perpendicular to the road. Clean quartz sand was used as collector material. Mass-specific magnetic susceptibility (χ) and the concentration of pollutants (HM, PAH) all show a significant increase with time in the box samples, however, there are obviously also seasonal and site-dependent effects which lead to more stable values over several months or even some decrease in the upper few cm due to vertical migration. Similar significant differences of χ, PAH and HM concentrations and an importance of splash-water were noticed in pillars and u-channels within one year of monitoring. Magnetic results revealed that magnetite-like phases are responsible for the enhancement of magnetic concentration. A good correlation between χ and semi-volatile and particle-bound PAH phases as well as HM suggests that χ can be used as a proxy for traffic derived PAH and HM pollution. SEM observations and EDX analyses identified a dominance of angular and aggregates-shaped particles with composition of Fe-Cr-Ni derived from traffic-specific activities (abrasion of tyres, exhausts and brake linings). The results from our monitoring studies will be utilized to develop new innovative roadside pollution monitoring concepts.

  16. Origin of anthropogenic hydrocarbons and halocarbons measured in the summertime european outflow (on Crete in 2001

    Directory of Open Access Journals (Sweden)

    V. Gros

    2003-01-01

    Full Text Available During the Mediterranean Intensive Oxidant Study MINOS in August 2001, 87 air samples were collected at the ground-based station Finokalia (35°19'N, 25°40'E on the north coast of Crete and subsequently analysed by GC-MS. The analysis includes various hydrocarbons, organo-halogens, HCFCs and CFCs. These compounds have a wide variety of sources and sinks and a large range of atmospheric lifetimes. We evaluated the characteristics of the sampling site in terms of proximity to individual sources by plotting the measured variability of these species against lifetime. The resulting linear relationship suggests that the sampling site is representative of intermediate conditions between a remote site and one that is in the vicinity of a wide variety of sources. Our analysis of air mass origin and chemical ratios also shows that several distinct anthropogenic sources influenced the atmospheric composition over Crete. Propane observations are compared to a global model to assess the fossil fuel related emission inventory. Although the model reproduces the general pattern of the propane variations, the model mixing ratios are systematically too low by a factor of 1.5 to 3, probably due to an underestimation of the propane emissions from east European countries in the underlying global database EDGAR. Another important finding was that methyl chloroform, a compound banned under the Montreal protocol, showed significant enhancements from background, which were well correlated with CFC-113. This suggests continued use and emission of methyl chloroform by one or more European countries. We also discuss the observed variations of methyl bromide and suggest that the significant peak observed on 12 August 2001 reflects heavy agricultural use as a soil fumigant in Italy.

  17. Emissions of Black Carbon Particles in Anthropogenic and Biomass Plumes over California during CARB 2008

    Science.gov (United States)

    Sahu, L. K.; Kondo, Y.; Moteki, N.; Takegawa, N.; Zhao, Y.; Vay, S. A.; Diskin, G. S.; Wisthaler, A.; Huey, L. G.

    2009-12-01

    Measurements of black carbon (BC) and other chemical species were made from the NASA DC-8 aircraft during the CARB campaign conducted over California in June 2008. We operated an SP2 system that measured BC and scattering particles. The vertical profiles of BC and scattering particles show enhancements in the lower troposphere. We have used relations of CO-CH3CN-SO2 to identify the sources of major plumes. The plumes originating from anthropogenic activities, mainly due to the use of fossil fuels (FF), were observed near the surface. However, the influence of smoke plumes from wild fire or biomass-burning (BB) sources was observed up to 3 km. Overall, the 1-minute average BC mass concentrations were in the ranges of about 90-500 ng/m3 and 300-700 ng/m3 in FF and BB plumes, respectively. The shell/core diameter ratios were much lagerer in BB plumes than those in FF plumes. Namely, the median shell/core ratios were 1.2-1.4 for FF plumes, while they were 1.4-1.7 for BB plumes. In both FF and BB plumes, the mass-size distributions of BC were single mode lognormal. However, the mass median diameters FF plumes were considerably smaller. The BC-CO2 regression slopes were 19±9 ng m-3/ppmv and 270±90 ng m-3/ppmv for FF and BB plumes, respectively. On the other hand the regression slopes of BC-CO were about 3.3 ng m-3/ppbv in both the plumes. Conversely, the regression slopes of BC with other co-emitted combustions products can be used to estimate the contributions of emissions from different sources.

  18. Controlling harmful cyanobacterial blooms in a world experiencing anthropogenic and climatic-induced change

    International Nuclear Information System (INIS)

    Harmful (toxic, food web altering, hypoxia generating) cyanobacterial algal blooms (CyanoHABs) are proliferating world-wide due to anthropogenic nutrient enrichment, and they represent a serious threat to the use and sustainability of our freshwater resources. Traditionally, phosphorus (P) input reductions have been prescribed to control CyanoHABs, because P limitation is widespread and some CyanoHABs can fix atmospheric nitrogen (N2) to satisfy their nitrogen (N) requirements. However, eutrophying systems are increasingly plagued with non N2 fixing CyanoHABs that are N and P co-limited or even N limited. In many of these systems N loads are increasing faster than P loads. Therefore N and P input constraints are likely needed for long-term CyanoHAB control in such systems. Climatic changes, specifically warming, increased vertical stratification, salinization, and intensification of storms and droughts play additional, interactive roles in modulating CyanoHAB frequency, intensity, geographic distribution and duration. In addition to having to consider reductions in N and P inputs, water quality managers are in dire need of effective tools to break the synergy between nutrient loading and hydrologic regimes made more favorable for CyanoHABs by climate change. The more promising of these tools make affected waters less hospitable for CyanoHABs by 1) altering the hydrology to enhance vertical mixing and/or flushing and 2) decreasing nutrient fluxes from organic rich sediments by physically removing the sediments or capping sediments with clay. Effective future CyanoHAB management approaches must incorporate both N and P loading dynamics within the context of altered thermal and hydrologic regimes associated with climate change. - Research Highlights: → Toxic cyanobacterial blooms (CyanoHABs) increasingly threaten global water supplies. → Human (nutrient) and climate (hydrology, temperature) changes synergistically promote CyanoHABs. → CyanoHAB control involves

  19. Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

    International Nuclear Information System (INIS)

    Stable nitrogen isotopic composition (δ15N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ15N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ15N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: → δ15N of aquatic insects increases downstream with anthropogenic nitrogen inputs. → δ15N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. → The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

  20. Enhancement of two dimensional electron gas concentrations due to Si3N4 passivation on Al0.3Ga0.7N/GaN heterostructure: strain and interface capacitance analysis

    Directory of Open Access Journals (Sweden)

    Syed Mukulika Dinara

    2015-04-01

    Full Text Available Enhancement of two dimensional electron gas (2DEG concentrations at Al0.3Ga0.7N/GaN hetero interface after a-Si3N4 (SiN passivation has been investigated from non-destructive High Resolution X-ray Diffraction (HRXRD analysis, depletion depth and capacitance-voltage (C-V profile measurement. The crystalline quality and strained in-plane lattice parameters of Al0.3Ga0.7N and GaN were evaluated from double axis (002 symmetric (ω-2θ diffraction scan and double axis (105 asymmetric reciprocal space mapping (DA RSM which revealed that the tensile strain of the Al0.3Ga0.7N layer increased by 15.6% after SiN passivation. In accordance with the predictions from theoretical solution of Schrödinger-Poisson’s equations, both electrochemical capacitance voltage (ECV depletion depth profile and C-V characteristics analyses were performed which implied effective 9.5% increase in 2DEG carrier density after passivation. The enhancement of polarization charges results from increased tensile strain in the Al0.3Ga0.7N layer and also due to the decreased surface states at the interface of SiN/Al0.3Ga0.7N layer, effectively improving the carrier confinement at the interface.

  1. The phosphodiesterase 4 inhibitor roflumilast augments the Th17-promoting capability of dendritic cells by enhancing IL-23 production, and impairs their T cell stimulatory activity due to elevated IL-10.

    Science.gov (United States)

    Bros, Matthias; Montermann, Evelyn; Cholaszczyńska, Anna; Reske-Kunz, Angelika B

    2016-06-01

    Phosphodiesterase 4 (PDE4) inhibitors serve to prevent degradation of the intracellular second messenger cAMP, resulting in broad anti-inflammatory effects on different cell types including immune cells. Agents that elevate cAMP levels via activation of adenylate cyclase have been shown to imprint a Th17-promoting capacity in dendritic cells (DCs). Therefore, we studied the potential of therapeutically relevant PDE inhibitors to induce a pronounced Th17-skewing capacity in DCs. Here we show that mouse bone marrow-derived (BM-) DCs when treated with the PDE4 inhibitor roflumilast (ROF, trade name: Daxas) in the course of stimulation with LPS (ROF-DCs) evoked elevated IL-17 levels in cocultured allogeneic T cells. In addition, as compared with control settings, levels of IFN-γ remained unaltered, while contents of Th2 cytokines (IL-5, IL-10) were diminished. ROF enhanced expression of the Th17-promoting factor IL-23 in BM-DCs. In line, neutralizing antibodies specific for IL-23 or IL-6 when applied to DC/T cell cocultures partially inhibited the IL17-promoting effect of ROF-DCs. Furthermore, ROF-DCs displayed a markedly diminished allogeneic T cell stimulatory capacity due to enhanced production of IL-10, which was restored upon application of IL-10 specific neutralizing antibody to DC/T cell cocultures. Both the IL-17-inducing and impaired T cell stimulatory capacity of BM-DCs were mimicked by a specific activator of protein kinase A, while stimulation of EPACs (exchange proteins of activated cAMP) did not yield such effects. Taken together, our findings suggest that PDE4 inhibitors aside from their broad overall anti-inflammatory effects may enhance the Th17-polarizing capacity in DCs as an unwanted side effect. PMID:27070502

  2. Anthropogenic CO2 emissions in Africa

    Directory of Open Access Journals (Sweden)

    R. A. Houghton

    2008-11-01

    Full Text Available An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2 emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 TgC y−1 for the period 2000–2005. These emissions resulted from the combustion of fossil fuels (260 TgC y−1 and land use change (240 TgC y−1. Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 TgC accounting for 3.7% of the global emissions. The 2000–2005 growth rate in African fossil fuel emissions was 3.2% y−1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 tC y−1 compared to the global average of 1.2 tC y−1. The average amount of carbon (C emitted as CO2 to produce 1 US $ of Gross Domestic Product (GDP in Africa in 2005 was 187 gC/$, close to the world average of 199 gC/$. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

  3. Multidisciplinary study on anthropogenic landslides in Nepal

    Science.gov (United States)

    Puglia, Christopher; Derron, Marc-Henri; Nicolet, Pierrick; Sudmeier-Rieux, Karen; Jaboyedoff, Michel; Devkota, Sanjay

    2013-04-01

    Nepal is a country in which shallow landslide is a frequent phenomenon. Monsoon is the main triggering factor but anthropogenic influence is often significant too. Indeed, many infrastructures, such as roads or water pipes, are not built in a rigorous way because of a lack of funds and knowledge. In the present study we examine the technical, social and economic issues of landslide management for two sites in Nepal. The first site is located in Sanusiruwari VDC (Sindhupalchock district, central Nepal) and the second one in Namadi VDC (Ramecchap district, central Nepal). Both sites are affected by landslides induced by the construction of hydropower plants. These landslides may threaten the viability of the hydropower plants. At both sites the problems are quite similar, but the first site project is a private one and the second one is a public one implemented by the United Nations Development Programme (UNDP). For both sites, bioengineering methods using Vetiver (Vetyveria zizanioides) plantations is the main stabilization measure. To follow the progression of both landslides, fieldwork observations were conducted before and after the 2012 rainy season, including photogrammetric and distancemeter acquisitions. Main issues were discussed with communities and stakeholders of the hydropower projects through interviews and participatory risk mapping. Main issues include: lack of communication between the project managers and communities leading to conflict and the lack of maintenance of the bio-engineering sites, leading to less effective Vetiver growth and slope stabilization. Comparing the landslide management (technical, social and economic) of the two projects allows to point out some specific issues within an integrated risk perspective.

  4. Continental anthropogenic primary particle number emissions

    Science.gov (United States)

    Paasonen, Pauli; Kupiainen, Kaarle; Klimont, Zbigniew; Visschedijk, Antoon; Denier van der Gon, Hugo A. C.; Amann, Markus

    2016-06-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas-Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol-cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening

  5. Effects of anthropogenic metallic contamination on cholinesterases of Gambusia holbrooki

    International Nuclear Information System (INIS)

    Highlights: • Metals are widespread in the aquatic compartment due to anthropogenic activities. • Metals can cause important anticholinesterasic effects in fish, already documented. • Metals Pb, Cu Zin and Cd did not significantly impair cholinesterases of G. holbrooki. • The role of ChE inhibition in the analysis of metal toxicity must be reconsidered. -- Abstract: Metal contamination causes multiple biological dysfunctions, including impairment of key physiological functions by targeting enzymes. This feature is a matter of concern, since it may imply significant disturbances in energy allocation, behaviour, reproduction, and survival. Inhibition of the cholinesterase (ChE) activity of aquatic organisms by metals has been described, and systematically used in biomonitoring studies as effect criterion of environmental exposure to these compounds. The present paper addresses the feasibility of using ChE inhibition to quantify the adverse acute and chronic effects of metals (copper, zinc, lead, and cadmium) on nervous tissue of Gambusia holbrooki. With the exception of acute exposure to copper, ChE activity was not significantly impaired. The meanings of the reported findings are further discussed, aiming at a more comprehensive use of this biomarker in environmental assessment. Based on the obtained results, the role of ChE inhibition in environmental metal contamination scenarios should be questioned or even discarded

  6. Direct shortwave forcing of climate by anthropogenic sulfate aerosol: Sensitivity to particle size, composition, and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Nemesure, S.; Wagener, R.; Schwartz, S.E. [Brookhaven National Lab., Upton, New York (United States)

    1996-04-01

    Recent estimates of global or hemispheric average forcing of climate by anthropogenic sulfate aerosol due to scattering of shortwave radiation are uncertain by more than a factor of 2. This paper examines the sensitivity of forcing to these microphysical properties for the purposes of obtaining a better understanding of the properties required to reduce the uncertainty in the forcing.

  7. Detection and attribution of anthropogenic forcing to diurnal temperature range changes from 1950 to 1999: comparing multi-model simulations with observations

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Liming [Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA (United States); Dickinson, Robert E. [The University of Texas at Austin, Department of Geological Sciences, Austin, TX (United States); Dai, Aiguo [National Center for Atmospheric Research, Boulder, CO (United States); Dirmeyer, Paul [Center for Ocean-Land-Atmosphere Studies, Calverton, MD (United States)

    2010-12-15

    Observations show that the surface diurnal temperature range (DTR) has decreased since 1950s over most global land areas due to a smaller warming in maximum temperatures (T{sub max}) than in minimum temperatures (T{sub min}). This paper analyzes the trends and variability in T{sub max}, T{sub min}, and DTR over land in observations and 48 simulations from 12 global coupled atmosphere-ocean general circulation models for the later half of the 20th century. It uses the modeled changes in surface downward solar and longwave radiation to interpret the modeled temperature changes. When anthropogenic and natural forcings are included, the models generally reproduce observed major features of the warming of T{sub max} and T{sub min} and the reduction of DTR. As expected the greenhouse gases enhanced surface downward longwave radiation (DLW) explains most of the warming of T{sub max} and T{sub min} while decreased surface downward shortwave radiation (DSW) due to increasing aerosols and water vapor contributes most to the decreases in DTR in the models. When only natural forcings are used, none of the observed trends are simulated. The simulated DTR decreases are much smaller than the observed (mainly due to the small simulated T{sub min} trend) but still outside the range of natural internal variability estimated from the models. The much larger observed decrease in DTR suggests the possibility of additional regional effects of anthropogenic forcing that the models can not realistically simulate, likely connected to changes in cloud cover, precipitation, and soil moisture. The small magnitude of the simulated DTR trends may be attributed to the lack of an increasing trend in cloud cover and deficiencies in charactering aerosols and important surface and boundary-layer processes in the models. (orig.)

  8. Sensitivity of soil organic matter in anthropogenically disturbed organic soils

    Science.gov (United States)

    Säurich, Annelie; Tiemeyer, Bärbel; Bechtold, Michel; Don, Axel; Freibauer, Annette

    2016-04-01

    Drained peatlands are hotspots of carbon dioxide (CO2) emissions from agriculture. However, the variability of CO2 emissions increases with disturbance, and little is known on the soil properties causing differences between seemingly similar sites. Furthermore the driving factors for carbon cycling are well studied for both genuine peat and mineral soil, but there is a lack of information concerning soils at the boundary between organic and mineral soils. Examples for such soils are both soils naturally relatively high in soil organic matter (SOM) such as Humic Gleysols and former peat soils with a relative low SOM content due to intensive mineralization or mixing with underlying or applied mineral soil. The study aims to identify drivers for the sensitivity of soil organic matter and therefore for respiration rates of anthropogenically disturbed organic soils, especially those near the boundary to mineral soils. Furthermore, we would like to answer the question whether there are any critical thresholds of soil organic carbon (SOC) concentrations beyond which the carbon-specific respiration rates change. The German agricultural soil inventory samples all agricultural soils in Germany in an 8x8 km² grid following standardized protocols. From this data and sample base, we selected 120 different soil samples from more than 80 sites. As reference sites, three anthropogenically undisturbed peatlands were sampled as well. We chose samples from the soil inventory a) 72 g kg-1 SOC and b) representing the whole range of basic soil properties: SOC (72 to 568 g kg-1), total nitrogen (2 to 29 g kg-1), C-N-ratio (10 to 80) bulk density (0.06 to 1.41 g/cm³), pH (2.5 to 7.4), sand (0 to 95 %) and clay (2 to 70 %) content (only determined for samples with less than 190 g kg-1 SOC) as well as the botanical origin of the peat (if determinable). Additionally, iron oxides were determined for all samples. All samples were sieved (2 mm) and incubated at standardized water content and

  9. Gastropod diversity, distribution and abundance in habitats with and without anthropogenic disturbances in Lake Victoria, Kenya

    DEFF Research Database (Denmark)

    Lange, C. N.; Kristensen, Thomas K.; Madsen, Henry

    2013-01-01

    We investigated freshwater gastropod diversity, abundance and distribution in habitats with and without anthropogenic disturbance in two localities, Ndere in the Winam Gulf and Mbita Point, Lake Victoria, Kenya, from May 2002 to January 2004. A total of 133 984 gastropod specimens belonging to 15...... species were recorded, 14 from Mbita and 12 from Ndere. Two species, Ferrissia kavirondica and Cleopatra cridlandi, which were recorded only from undisturbed habitats, could be indicators of least disturbed habitats. Water chemistry did differ between fish landing sites and undisturbed habitats at some...... sampling times, indicating that differences due to human impact do exist, but these are dependent on periods of calm weather. The study shows that anthropogenic disturbances cause ecological changes that can be exploited by some snail species, especially Biomphalaria choanomphala and Melanoides tuberculata...

  10. Modelling of long-term anthropogenic changes in stratospheric temperature and the ozone layer

    International Nuclear Information System (INIS)

    Complete text of publication follows. A numerical two-dimensional interactive dynamical-radiative-photochemical model including aerosol physics is used to examine the expected long-term changes in stratospheric temperature and the Earth's ozone layer due to anthropogenic pollution of the atmosphere by the greenhouse gases CO2, CH4, N2O and by ozone-depleting chlorine and bromine compounds. The model time-dependent runs were made for the period from 1975 to 2050. The mechanisms of the impact of each of the pollutants on stratospheric temperature have been analysed, their relative contributions to the predicted temperature change have been estimated. The processes, which determine the influence of anthropogenic growth of atmospheric abundance of the greenhouse gases on the dynamics of recovery of the Earth's ozone layer after reduction of anthropogenic discharges of ozone-depleting chlorine and bromine compounds into the atmosphere, have been studied in details. The contributions of different pollutions to the predicted ozone changes have been estimated. The results of the calculations show that the basic mechanism by which greenhouse gases influence the ozone layer is stratospheric cooling accompanied by a weakness in the efficiency of the catalytic cycles of ozone destruction due to temperature dependencies of the photochemical gas-phase reactions. Modification of polar stratospheric clouds (PSCs) caused by anthropogenic growth of the greenhouse gases is important only for the polar ozone. An essential influence of the greenhouse gases on the ozone by a modification of the stratospheric sulphate aerosol is revealed. The aerosol changes caused by the greenhouse gases modify the distribution of the ozone-active gaseous chlorine, bromine and nitrogen components by means of heterogeneous reactions on the aerosol surface, resulting in a significant decrease in springtime polar ozone depletion of the Antarctic ozone hole.

  11. Modeling Agassiz's Desert Tortoise Population Response to Anthropogenic Stressors

    Science.gov (United States)

    Mojave Desert tortoise (Gopherus agassizii) populations are exposed to a variety of anthropogenic threats, which vary in nature, severity, and frequency. Tortoise management in conservation areas can be compromised when the relative importance of these threats is not well underst...

  12. Screening of anthropogenic compounds in polluted sediments and soils

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Leeuw, J.W. de; Leer, E.W.B. de; Schuyl, P.J.W.

    1986-01-01

    The use of flash evaporation and pyrolysis gas chromatography- mass spectrometry as a fast screening procedure for anthropogenic substances In environmental samples is demonstrated by the analysis of polluted soil and sediment samples. Polycyclic aromatic hydrocarbons, haloorganics, aliphatlc hydroc

  13. Anthropogenic climate change in the Playa Lakes Joint Venture region

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Anthropogenic climate change has been driving regional climate shifts in the Playa Lakes Joint Venture zone since at least the mid 1970s. As a result, summers are...

  14. Impact of anthropogenic heat on urban climate in Tokyo

    Science.gov (United States)

    Ichinose, Toshiaki; Shimodozono, Kazuhiro; Hanaki, Keisuke

    This study quantifies the contribution through energy consumption, to the heat island phenomena and discussed how reductions in energy consumption could mitigate impacts on the urban thermal environment. Very detailed maps of anthropogenic heat in Tokyo were drawn with data from energy statistics and a very detailed digital geographic land use data set including the number of stories of building at each grid point. Animated computer graphics of the annual and diurnal variability in Tokyo's anthropogenic heat were also prepared with the same data sources. These outputs characterize scenarios of anthropogenic heat emission and can be applied to a numerical simulation model of the local climate. The anthropogenic heat flux in central Tokyo exceeded 400 W m -2 in daytime, and the maximum value was 1590 W m -2 in winter. The hot water supply in offices and hotels contributed 51% of this 1590 W m -2. The anthropogenic heat flux from the household sector in the suburbs reached about 30 W m -2 at night. Numerical simulations of urban climate in Tokyo were performed by referring to these maps. A heat island appeared evident in winter because of weakness of the sea breeze from Tokyo Bay. At 8 p.m., several peaks of high-temperature appeared, around Otemachi, Shinjuku and Ikebukuro; the areas with the largest anthropogenic heat fluxes. In summer the shortwave radiation was strong and the influence of anthropogenic heat was relatively small. In winter, on the other hand, the shortwave radiation was weak and the influence of anthropogenic heat was relatively large. The effects of reducing energy consumption, by 50% for hot water supply and 100% for space cooling, on near surface air temperature would be at most -0.5°C.

  15. Role of anthropogenic direct heat emissions in global warming

    OpenAIRE

    Wang, Fei; Mu, Xingmin; Zhao, Guangju; Gao, Peng; Li, Pengfei

    2015-01-01

    The anthropogenic emissions of greenhouse gases (GHG) are widely realized as the predominant drivers of global warming, but the huge and increasing anthropogenic direct heat emissions (AHE) has not gained enough attention in terms of its role in the warming of the climate system. Based on two reasonable assumptions of (1) AHE eventually transfers to the Earth energy system and (2) the net warming is only driven by the net radioactive forcing (RF) from either GHG or other causes, we analyzed t...

  16. Increasing potential of biomass burning over Sumatra, Indonesia induced by anthropogenic tropical warming

    International Nuclear Information System (INIS)

    Uncontrolled biomass burning in Indonesia during drought periods damages the landscape, degrades regional air quality, and acts as a disproportionately large source of greenhouse gas emissions. The expansion of forest fires is mostly observed in October in Sumatra favored by persistent droughts during the dry season from June to November. The contribution of anthropogenic warming to the probability of severe droughts is not yet clear. Here, we show evidence that past events in Sumatra were exacerbated by anthropogenic warming and that they will become more frequent under a future emissions scenario. By conducting two sets of atmospheric general circulation model ensemble experiments driven by observed sea surface temperature for 1960–2011, one with and one without an anthropogenic warming component, we found that a recent weakening of the Walker circulation associated with tropical ocean warming increased the probability of severe droughts in Sumatra, despite increasing tropical-mean precipitation. A future increase in the frequency of droughts is then suggested from our analyses of the Coupled Model Intercomparison Project Phase 5 model ensembles. Increasing precipitation to the north of the equator accompanies drier conditions over Indonesia, amplified by enhanced ocean surface warming in the central equatorial Pacific. The resultant precipitation decrease leads to a ∼25% increase in severe drought events from 1951–2000 to 2001–2050. Our results therefore indicate the global warming impact to a potential of wide-spreading forest fires over Indonesia, which requires mitigation policy for disaster prevention. (letter)

  17. Do Anthropogenic Dark Earths Occur in the Interior of Borneo? Some Initial Observations from East Kalimantan

    Directory of Open Access Journals (Sweden)

    Meine van Noordwijk

    2012-05-01

    Full Text Available Anthropogenic soils of the Amazon Basin (Terra Preta, Terra Mulata reveal that pre-Colombian peoples made lasting improvements in the agricultural potential of nutrient-poor soils. Some have argued that applying similar techniques could improve agriculture over much of the humid tropics, enhancing local livelihoods and food security, while also sequestering large quantities of carbon to mitigate climate change. Here, we present preliminary evidence for Anthropogenic Dark Earths (ADEs in tropical Asia. Our surveys in East Kalimantan (Indonesian Borneo identified several sites where soils possess an anthropogenic development and context similar in several respects to the Amazon’s ADEs. Similarities include riverside locations, presence of useful fruit trees, spatial extent as well as soil characteristics such as dark color, high carbon content (in some cases, high phosphorus levels, and improved apparent fertility in comparison to neighboring soils. Local people value these soils for cultivation but are unaware of their origins. We discuss these soils in the context of local history and land-use and identify numerous unknowns. Incomplete biomass burning appears key to these modified soils. More study is required to clarify soil transformations in Borneo and to determine under what circumstances such soil improvements might remain ongoing.

  18. Modeling of the anthropogenic heat flux and its effect on air quality over the Yangtze River Delta region, China

    Directory of Open Access Journals (Sweden)

    M. Xie

    2015-11-01

    Full Text Available Anthropogenic heat (AH emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and the diurnal variations into the simulations. By running this upgraded WRF/Chem for two typical months in 2010, the impacts of AH on the meteorology and air quality over the YRD region are studied. The results show that the AH fluxes over YRD have been growing in recent decades. In 2010, the annual mean values of AH over Shanghai, Jiangsu and Zhejiang are 14.46, 2.61 and 1.63 W m−2 respectively, with the high values of 113.5 W m−2 occurring in the urban areas of Shanghai. These AH emissions can significantly change the urban heat island and urban-breeze circulations in the cities of the YRD region. In Shanghai, 2 m air temperature increases by 1.6 °C in January and 1.4 °C in July, the planetary boundary layer height rises up by 140 m in January and 160 m in July, and 10 m wind speed is enhanced by 0.7 m s−1 in January and 0.5 m s−1 in July, with higher increment at night. And the enhanced vertical movement can transport more moisture to higher levels, which causes the decrease of water vapor at the ground level and the increase in the upper PBL, and thereby induces the accumulative precipitation to increase by 15–30 % over the megacities in July. The adding AH can impact the spatial and vertical distributions of the simulated pollutants as well. The concentrations of primary air pollutants decrease near surface and increase at the upper levels, due mainly to the increases of PBLH, surface wind speed and upward air vertical movement. But surface O3 concentrations increase in the urban areas, with maximum changes

  19. Long-term variations in the South Asian monsoon annual cycle: the role of regional anthropogenic aerosol forcing

    Science.gov (United States)

    Bollasina, Massimo; Ming, Yi

    2013-04-01

    Detection and attribution of long-term variations of the South Asian monsoon is of extreme importance. Indeed, even small changes in the onset and duration of the monsoon season or in the spatial distribution of the seasonal mean precipitation may severely impact agriculture, health, water availability, ecosystems, and economy for a substantial fraction of the world's population. In the past decades emissions of aerosols have dramatically increased over South Asia due to rapid urbanization and population growth. As a result, the study of the impact of anthropogenic aerosols on the monsoon has recently emerged as one of the topics of highest priority in the scientific community. This study makes use of a state-of-the-art coupled climate model, the GFDL CM3, to investigate two aspects of the aerosol influence on the 20th-century changes in the monsoon. The model has fully-interactive aerosols and a representation of both direct and indirect effects. Aerosols are responsible for the advancement of the monsoon onset over India, leading, in agreement with observations, to enhanced precipitation in June over most parts of the subcontinent. Our experiments show that the earlier onset is preceded in early spring by a strong aerosol forcing over the Bay of Bengal and Indonesia and associated atmospheric circulation anomalies. The latter triggers thermodynamical changes over the northwestern part of the Subcontinent in May and June, including enhanced surface heating, which in turn drive the movement of the monsoon to the west. We also performed historical experiments with time-evolving radiative forcings aimed at isolating the contribution of regional versus remote anthropogenic aerosol emissions on the observed 20th century widespread drying of the Indian monsoon. Indian-only aerosol sources are found to play a predominant role in generating suppressed rainfall over the subcontinent, especially during early summer. Remote aerosols contribute, although in a minor way, to

  20. Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia

    Directory of Open Access Journals (Sweden)

    K. Ding

    2014-11-01

    Full Text Available East Asia has experienced rapid development with increasing CO emission in the past decades. Therefore, uplifting CO from the boundary layer to the free troposphere in East Asia can have great implications on regional air quality. It can also influence global climate due to the longer lifetime of CO at higher altitudes. In this study, three cases of high CO episodes in East Asia from 2003 to 2005 are examined with spaceborne Measurements Of Pollution In The Troposphere (MOPITT data, in combination with aircraft measurements from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC program. High CO abundances of 300–550 ppbv were observed in MOZAIC data in the free troposphere during these episodes. These are among the highest CO abundances documented at these altitudes. Correspondingly, elevated CO was shown in MOPITT daytime data in the middle to upper troposphere in the 2003 case, mostly in the lower to middle troposphere in the 2004 case, and in the upper troposphere in the 2005 case. Through analyses of the simulations from a chemical transport model GEOS-Chem and a trajectory dispersion model FLEXPART, we found different CO signatures in the elevated CO and distinct transport pathways and mechanisms for these cases. In the 2003 case, CO from large forest fires near Lake Baikal dominated the elevated CO, which had been rapidly transported upward by a~frontal system from the fire plumes. In the 2004 case, anthropogenic CO from the North China Plain experienced frontal lifting and mostly reached ~ 700 hPa near the East China Sea, while CO from biomass burning from Indochina experienced orographic lifting, leeside-trough induced convection, and frontal lifting through two separate transport pathways, leading to two distinct CO enhancements around 700 hPa and 300 hPa. In the 2005 case, high CO of ~ 300 ppbv, observed in the MOZAIC data around 350 hPa, originated from the anthropogenic source over the vicinity of the

  1. Modeling of the anthropogenic heat flux and its effect on air quality over the Yangtze River Delta region, China

    Science.gov (United States)

    Xie, M.; Liao, J.; Wang, T.; Zhu, K.; Zhuang, B.; Han, Y.; Li, M.; Li, S.

    2015-11-01

    Anthropogenic heat (AH) emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD) region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and the diurnal variations into the simulations. By running this upgraded WRF/Chem for two typical months in 2010, the impacts of AH on the meteorology and air quality over the YRD region are studied. The results show that the AH fluxes over YRD have been growing in recent decades. In 2010, the annual mean values of AH over Shanghai, Jiangsu and Zhejiang are 14.46, 2.61 and 1.63 W m-2 respectively, with the high values of 113.5 W m-2 occurring in the urban areas of Shanghai. These AH emissions can significantly change the urban heat island and urban-breeze circulations in the cities of the YRD region. In Shanghai, 2 m air temperature increases by 1.6 °C in January and 1.4 °C in July, the planetary boundary layer height rises up by 140 m in January and 160 m in July, and 10 m wind speed is enhanced by 0.7 m s-1 in January and 0.5 m s-1 in July, with higher increment at night. And the enhanced vertical movement can transport more moisture to higher levels, which causes the decrease of water vapor at the ground level and the increase in the upper PBL, and thereby induces the accumulative precipitation to increase by 15-30 % over the megacities in July. The adding AH can impact the spatial and vertical distributions of the simulated pollutants as well. The concentrations of primary air pollutants decrease near surface and increase at the upper levels, due mainly to the increases of PBLH, surface wind speed and upward air vertical movement. But surface O3 concentrations increase in the urban areas, with maximum changes of 2.5 ppb in January and 4

  2. A simple modeling approach to study the regional impact of a Mediterranean forest isoprene emission on anthropogenic plumes

    Directory of Open Access Journals (Sweden)

    J. Cortinovis

    2005-01-01

    Full Text Available Research during the past decades has outlined the importance of biogenic isoprene emission in tropospheric chemistry and regional ozone photo-oxidant pollution. The first part of this article focuses on the development and validation of a simple biogenic emission scheme designed for regional studies. Experimental data sets relative to Boreal, Tropical, Temperate and Mediterranean ecosystems are used to estimate the robustness of the scheme at the canopy scale, and over contrasted climatic and ecological conditions. A good agreement is generally found when comparing field measurements and simulated emission fluxes, encouraging us to consider the model suitable for regional application. Limitations of the scheme are nevertheless outlined as well as further on-going improvements. In the second part of the article, the emission scheme is used on line in the broader context of a meso-scale atmospheric chemistry model. Dynamically idealized simulations are carried out to study the chemical interactions of pollutant plumes with realistic isoprene emissions coming from a Mediterranean oak forest. Two types of anthropogenic sources, respectively representative of the Marseille (urban and Martigues (industrial French Mediterranean sites, and both characterized by different VOC/NOx are considered. For the Marseille scenario, the impact of biogenic emission on ozone production is larger when the forest is situated in a sub-urban configuration (i.e. downwind distance TOWN-FOREST -1. In this case the enhancement of ozone production due to isoprene can reach +37% in term of maximum surface concentrations and +11% in term of total ozone production. The impact of biogenic emission decreases quite rapidly when the TOWN-FOREST distance increases. For the Martigues scenario, the biogenic impact on the plume is significant up to TOWN-FOREST distance of 90km where the ozone maximum surface concentration enhancement can still reach +30%. For both cases, the

  3. Anthropogenic perturbation of the carbon fluxes from land to ocean

    KAUST Repository

    Regnier, Pierre

    2013-06-09

    A substantial amount of the atmospheric carbon taken up on land through photosynthesis and chemical weathering is transported laterally along the aquatic continuum from upland terrestrial ecosystems to the ocean. So far, global carbon budget estimates have implicitly assumed that the transformation and lateral transport of carbon along this aquatic continuum has remained unchanged since pre-industrial times. A synthesis of published work reveals the magnitude of present-day lateral carbon fluxes from land to ocean, and the extent to which human activities have altered these fluxes. We show that anthropogenic perturbation may have increased the flux of carbon to inland waters by as much as 1.0 Pg C yr -1 since pre-industrial times, mainly owing to enhanced carbon export from soils. Most of this additional carbon input to upstream rivers is either emitted back to the atmosphere as carbon dioxide (∼0.4 Pg C yr -1) or sequestered in sediments (∼0.5 Pg C yr -1) along the continuum of freshwater bodies, estuaries and coastal waters, leaving only a perturbation carbon input of ∼0.1 Pg C yr -1 to the open ocean. According to our analysis, terrestrial ecosystems store ∼0.9 Pg C yr -1 at present, which is in agreement with results from forest inventories but significantly differs from the figure of 1.5 Pg C yr -1 previously estimated when ignoring changes in lateral carbon fluxes. We suggest that carbon fluxes along the land-ocean aquatic continuum need to be included in global carbon dioxide budgets.

  4. How does the anthropogenic activity affect the spring discharge?

    Science.gov (United States)

    Hao, Yonghong; Zhang, Juan; Wang, Jiaojiao; Li, Ruifang; Hao, Pengmei; Zhan, Hongbin

    2016-09-01

    Karst hydrological process has largely been altered by climate change and human activity. In many places throughout the world, human activity (e.g. groundwater pumping and dewatering from mining) has intensified and surpassed climate change, where human activity becomes the primary factor that affects groundwater system. But it is still largely unclear how the human activity affects spring discharge in magnitude and periodicity. This study investigates the effects of anthropogenic activity on spring discharge, using the Xin'an Springs of China as an example. The Xin'an Spring discharge were divided into two time periods: the pre-development period from 1956 to 1971 and the post-development period from 1972 to 2013. We confirm the dividing time (i.e. 1971) of these two periods using the Wilcoxon rank-sum test. Then the wavelet transform and wavelet coherence were used to analyze the karst hydrological processes for the two periods respectively. We analyze the correlations of precipitation and the Xin'an spring discharge with the monsoons including the Indian Summer Monsoon (ISM) and the West North Pacific Monsoon (WNPM) and the climate teleconnections including El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), respectively. The results indicated that the spring discharge was attenuated about 19.63% under the influence of human activity in the Xin'an Springs basin. However, human activity did not alter the size of the resonance frequencies between the spring discharge and the monsoons. In contrast, it reinforced the periodicities of the monsoons-driven spring discharge. It suggested that human has adapted to the major climate periodicities, and human activity had the same rhyme with the primary climate periodicity. In return, human activity enhances the correlation between the monsoons and the spring discharge.

  5. Simple but accurate GCM-free approach for quantifying anthropogenic climate change

    Science.gov (United States)

    Lovejoy, S.

    2014-12-01

    We are so used to analysing the climate with the help of giant computer models (GCM's) that it is easy to get the impression that they are indispensable. Yet anthropogenic warming is so large (roughly 0.9oC) that it turns out that it is straightforward to quantify it with more empirically based methodologies that can be readily understood by the layperson. The key is to use the CO2 forcing as a linear surrogate for all the anthropogenic effects from 1880 to the present (implicitly including all effects due to Greenhouse Gases, aerosols and land use changes). To a good approximation, double the economic activity, double the effects. The relationship between the forcing and global mean temperature is extremely linear as can be seen graphically and understood without fancy statistics, [Lovejoy, 2014a] (see the attached figure and http://www.physics.mcgill.ca/~gang/Lovejoy.htm). To an excellent approximation, the deviations from the linear forcing - temperature relation can be interpreted as the natural variability. For example, this direct - yet accurate approach makes it graphically obvious that the "pause" or "hiatus" in the warming since 1998 is simply a natural cooling event that has roughly offset the anthropogenic warming [Lovejoy, 2014b]. Rather than trying to prove that the warming is anthropogenic, with a little extra work (and some nonlinear geophysics theory and pre-industrial multiproxies) we can disprove the competing theory that it is natural. This approach leads to the estimate that the probability of the industrial scale warming being a giant natural fluctuation is ≈0.1%: it can be dismissed. This destroys the last climate skeptic argument - that the models are wrong and the warming is natural. It finally allows for a closure of the debate. In this talk we argue that this new, direct, simple, intuitive approach provides an indispensable tool for communicating - and convincing - the public of both the reality and the amplitude of anthropogenic warming

  6. Predicting anthropogenic soils across the Amazonia

    Science.gov (United States)

    Mcmichael, C.; Palace, M. W.; Bush, M. B.; Braswell, B. H.; Hagen, S. C.; Silman, M.; Neves, E.; Czarnecki, C.

    2012-12-01

    of area covered by terra preta. Distance to river, locations of bluffs, elevation, and soil fertility were important factors in determining distributions of terra preta, while other environmental variables had less effect. Terra pretas were most likely to be found in central and eastern Amazonia near the confluences of the Amazon River and its major tributaries. Within this general area of higher probability, terra pretas are most likely found atop the bluffs overlooking the rivers as opposed to lying on the floodplain. Interestingly, terra pretas are more probable in areas with less-fertile and more highly weathered soils. Although all three modeling techniques provided similar predictions of terra preta across Amazonia, we suggest that maximum entropy modeling is the best technique to predict anthropogenic soils across the vast Amazonian landscape. The auto-logistic regression corrects for spatial autocorrelation inherent to archaeological surveys, but still requires absence data, which was collected at different times and on different spatial scales than the presence data. The maximum entropy model requires presence only data, accounts for spatial autocorrelation, and is not affected by the differential soil sampling techniques.

  7. Spring flood pH decline in northern Sweden: Towards an operational model separating natural acidity from anthropogenic acidification

    Energy Technology Data Exchange (ETDEWEB)

    Laudon, H.

    1999-10-01

    The spring flood is a defining feature of the ecosystem in northern Sweden. In this region, spring flood is an occasion for dramatic hydrochemical changes that profoundly effect the biodiversity of the aquatic ecosystem. Spring flood is also the period most susceptible to anthropogenic acidification. A belief in the anthropogenic component to pH decline during spring flood has been an important factor in spending over half a billion crowns to lime surface waters in Northern Sweden during the last decade. The natural component of episodic pH decline during spring flood, however, has received less attention. The main objective of this work is to present an operational model for separating and quantifying the anthropogenic and natural contributions of episodic acidification during high flow events in Northern Sweden. The key assumptions in this model are that baseflow ANC has not been affected by anthropogenic acidification, that DOC has not changed due to modern land-use practice and that natural dilution during hydrological episodes can be quantified. The limited data requirements of 10-15 stream water samples before and during spring flood make the model suitable for widespread use in environmental monitoring programs. This makes it possible to distinguish trends of human impact as well as natural pH decline in space and time. Modeling results from northern Sweden demonstrate that the natural driving mechanisms of dilution and organic acidity were the dominant factors in the episodic acidification of spring flood in the region. The anthropogenic contribution to spring pH decline was similar in size to the natural contribution in only two of the more than 30 events where this model was applied. Natural factors alone were found to cause pH values below 4.5 in some streams. Anthropogenic sources of acidity can be superimposed on this natural dynamics. In the sites studied, the magnitude of the anthropogenic ANC decline was correlated to the winter deposition of

  8. Effects of anthropogenic impacts on benthic macroinvertebrates assemblages in subtropical mountain streams

    Directory of Open Access Journals (Sweden)

    Leticia M. Mesa

    2013-12-01

    Full Text Available The nature of the riparian and surrounding landscape has been modified by anthropogenic activities, which may subsequently alter the composition and functional structure of macroinvertebrate assemblages. The effect of these changes on function of benthic fauna is difficult to assess due to the scarce knowledge on functional structures in tropical streams. In this study we evaluate whether sites impacted and unimpacted by anthropogenic alterations differed in assemblage composition and density, richness and diversity of each functional feeding group. The selection of the sites was related to their distinct riparian characteristics, following the QBRy riparian quality index. Collector-gatherer was the dominant functional feeding group, comprising 91% of total density, whereas the proportion of shredders was very low, representing less of 0.5% of total density. Asemblage composition of macroinvertebrates differed between impacted and unimpacted sites. Predators were dominant in taxa number, representing about 60% of total taxa richness. In addition, the diversity and richness of collector-gatherers differed significantly between degraded and unimpacted sites, reflecting the sensitivity of this group to environmental changes and the utility to be used in the assessment of anthropogenic modifications. The results of this study reinforce the idea that riparian corridor management is critical for the distribution of macroinvertebrate assemblages as well as functional organization of lotic streams.

  9. Characteristics of Anthropogenic Sulfate and Carbonaceous Aerosols over East Asia: Regional Modeling and Observation

    Institute of Scientific and Technical Information of China (English)

    Yan HUANG; William L. CHAMEIDES; Qian TAN; Robert E. DICKINSON

    2008-01-01

    The authors present spatial and temporal characteristics of anthropogenic sulfate and carbonaceous aerosols over East Asia using a 3-D coupled regional climate-chemistry-aerosol model, and compare the simulation with the limited aerosol observations over the region. The aerosol module consists of SO2, SO42-, hydrophobic and hydrophilic black carbon (BC) and organic carbon compounds (OC), including emission, advections, dry and wet deposition, and chemical production and conversion. The simulated patterns of SO2 are closely tied to its emission rate, with sharp gradients between the highly polluted regions and more rural areas. Chemical conversion (especially in the aqueous phase) and dry deposition remove 60% and 30% of the total SO2 emission, respectively. The SO42- shows less horizontal gradient and seasonality than SO2, with wet deposition (60%) and export (27%) being two major sinks. Carbonaceous aerosols are spatially smoother than sulfur species. The aging process transforms more than 80% of hydrophobic BC and OC to hydrophilic components, which are removed by wet deposition (60%) and export (30%). The simulated spatial and seasonal SO42-, BC and OC aerosol concentrations and total aerosol optical depth are generally consistent with the observations in rural areas over East Asia, with lower bias in simulated OC aerosols, likely due to the underestimation of anthropogenic OC emissions and missing treatment of secondary organic carbon. The results suggest that our model is a useful tool for characterizing the anthropogenic aerosol cycle and for assessing its potential climatic and environmental effects in future studies.

  10. Impacts of anthropogenic factors on land degradation during the anthropocene in Turkey.

    Science.gov (United States)

    Curebal, Isa; Efe, Recep; Soykan, Abdullah; Sonmez, Suleyman

    2015-01-01

    The aim of the present study was to determine the factors that effected the beginning of the Anthropogenic Era (human age) in Turkey and formation of biomes. Destruction of vegetation, soil erosion and land degradation are the most important factors in the formation of anthropogenic biomes in Turkey. For this reason, first of all, a literature review about land degradation, which has been going on for past 300 years in Turkey, and about its causes was made. Changes that have occurred over the last 70 years were studied with the help of aerial photos and satellite images. In addition, studies we have conducted in the last 35 years have contributed substantially to the determination of the extent of the destruction of vegetation and land degradation in Turkey. As a result of research based on literature reviews and fieldwork, the impact of humans on the natural habitat were identified, and the current situation was studied. The findings about the current situation that emerged due to human impact were then transferred to an electronic environment, and a map of anthropogenic biomes was produced with the help of ArcGIS Desktop software. Based on the results obtained, one can say that the natural habitat has considerably changed over the last 200 years; vegetation has been damaged, and land degradation has become faster because of human activities. These results indicate that 97% of natural biomes have become anthropogenic biomes, and this change has become more obvious during 20h century in Turkey. The results also show that the change has been more influential after 1950. PMID:26591882

  11. Incremental Reactivity Effects of Anthropogenic and Biogenic Volatile Organic Compounds on Secondary Organic Aerosol Formation

    Science.gov (United States)

    Kacarab, M.; Li, L.; Carter, W. P. L.; Cocker, D. R., III

    2015-12-01

    Two surrogate reactive organic gas (ROG) mixtures were developed to create a controlled reactivity environment simulating different urban atmospheres with varying levels of anthropogenic (e.g. Los Angeles reactivity) and biogenic (e.g. Atlanta reactivity) influences. Traditional chamber experiments focus on the oxidation of one or two volatile organic compound (VOC) precursors, allowing the reactivity of the system to be dictated by those compounds. Surrogate ROG mixtures control the overall reactivity of the system, allowing for the incremental aerosol formation from an added VOC to be observed. The surrogate ROG mixtures were developed based on that used to determine maximum incremental reactivity (MIR) scales for O3 formation from VOC precursors in a Los Angeles smog environment. Environmental chamber experiments were designed to highlight the incremental aerosol formation in the simulated environment due to the addition of an added anthropogenic (aromatic) or biogenic (terpene) VOC. All experiments were conducted in the UC Riverside/CE-CERT dual 90m3 environmental chambers. It was found that the aerosol precursors behaved differently under the two altered reactivity conditions, with more incremental aerosol being formed in the anthropogenic ROG system than in the biogenic ROG system. Further, the biogenic reactivity condition inhibited the oxidation of added anthropogenic aerosol precursors, such as m-xylene. Data will be presented on aerosol properties (density, volatility, hygroscopicity) and bulk chemical composition in the gas and particle phases (from a SYFT Technologies selected ion flow tube mass spectrometer, SIFT-MS, and Aerodyne high resolution time of flight aerosol mass spectrometer, HR-ToF-AMS, respectively) comparing the two controlled reactivity systems and single precursor VOC/NOx studies. Incremental aerosol yield data at different controlled reactivities provide a novel and valuable insight in the attempt to extrapolate environmental chamber

  12. Climatic effects of 1950–2050 changes in US anthropogenic aerosols – Part 2: Climate response

    Directory of Open Access Journals (Sweden)

    E. M. Leibensperger

    2011-08-01

    Full Text Available We investigate the climate response to US anthropogenic aerosol sources over the 1950 to 2050 period by using the NASA GISS general circulation model (GCM and comparing to observed US temperature trends. Time-dependent aerosol distributions are generated from the GEOS-Chem chemical transport model applied to historical emission inventories and future projections. Radiative forcing from US anthropogenic aerosols peaked in 1970–1990 and has strongly declined since due to air quality regulations. We find that the regional radiative forcing from US anthropogenic aerosols elicits a strong regional climate response, cooling the central and eastern US by 0.5–1.0 °C on average during 1970–1990, with the strongest effects on maximum daytime temperatures in summer and autumn. Aerosol cooling reflects comparable contributions from direct and indirect (cloud-mediated radiative effects. Absorbing aerosol (mainly black carbon has negligible warming effect. Aerosol cooling reduces surface evaporation and thus decreases precipitation along the US east coast, but also increases the southerly flow of moisture from the Gulf of Mexico resulting in increased cloud cover and precipitation in the central US. Observations over the eastern US show a lack of warming in 1960–1980 followed by very rapid warming since, which we reproduce in the GCM and attribute to trends in US anthropogenic aerosol sources. Present US aerosol concentrations are sufficiently low that future air quality improvements are projected to cause little further warming in the US (0.1 °C over 2010–2050. We find that most of the potential warming from aerosol source controls in the US has already been realized over the 1980–2010 period.

  13. Biological effects of anthropogenic contaminants in the San Francisco Estuary

    Science.gov (United States)

    Thompson, B.; Adelsbach, T.; Brown, C.; Hunt, J.; Kuwabara, J.; Neale, J.; Ohlendorf, H.; Schwarzbach, S.; Spies, R.; Taberski, K.

    2007-01-01

    Concentrations of many anthropogenic contaminants in the San Francisco Estuary exist at levels that have been associated with biological effects elsewhere, so there is a potential for them to cause biological effects in the Estuary. The purpose of this paper is to summarize information about biological effects on the Estuary's plankton, benthos, fish, birds, and mammals, gathered since the early 1990s, focusing on key accomplishments. These studies have been conducted at all levels of biological organization (sub-cellular through communities), but have included only a small fraction of the organisms and contaminants of concern in the region. The studies summarized provide a body of evidence that some contaminants are causing biological impacts in some biological resources in the Estuary. However, no general patterns of effects were apparent in space and time, and no single contaminant was consistently related to effects among the biota considered. These conclusions reflect the difficulty in demonstrating biological effects due specifically to contamination because there is a wide range of sensitivity to contaminants among the Estuary's many organisms. Additionally, the spatial and temporal distribution of contamination in the Estuary is highly variable, and levels of contamination covary with other environmental factors, such as freshwater inflow or sediment-type. Federal and State regulatory agencies desire to develop biological criteria to protect the Estuary's biological resources. Future studies of biological effects in San Francisco Estuary should focus on the development of meaningful indicators of biological effects, and on key organism and contaminants of concern in long-term, multifaceted studies that include laboratory and field experiments to determine cause and effect to adequately inform management and regulatory decisions. ?? 2006 Elsevier Inc. All rights reserved.

  14. Attribution of UK Winter Floods to Anthropogenic Forcing

    Science.gov (United States)

    Schaller, N.; Alison, K.; Sparrow, S. N.; Otto, F. E. L.; Massey, N.; Vautard, R.; Yiou, P.; van Oldenborgh, G. J.; van Haren, R.; Lamb, R.; Huntingford, C.; Crooks, S.; Legg, T.; Weisheimer, A.; Bowery, A.; Miller, J.; Jones, R.; Stott, P.; Allen, M. R.

    2014-12-01

    Many regions of southern UK experienced severe flooding during the 2013/2014 winter. Simultaneously, large areas in the USA and Canada were struck by prolonged cold weather. At the time, the media and public asked whether the general rainy conditions over northern Europe and the cold weather over North America were caused by climate change. Providing an answer to this question is not trivial, but recent studies show that probabilistic event attribution is feasible. Using the citizen science project weather@home, we ran over 40'000 perturbed initial condition simulations of the 2013/2014 winter. These simulations fall into two categories: one set aims at simulating the world with climate change using observed sea surface temperatures while the second set is run with sea surface temperatures corresponding to a world that might have been without climate change. The relevant modelled variables are then downscaled by a hydrological model to obtain river flows. First results show that anthropogenic climate change led to a small but significant increase in the fractional attributable risk for 30-days peak flows for the river Thames. A single number can summarize the final result from probabilistic attribution studies indicating, for example, an increase, decrease or no change to the risk of the event occurring. However, communicating this to the public, media and other scientists remains challenging. The assumptions made in the chain of models used need to be explained. In addition, extreme events, like the UK floods of the 2013/2014 winter, are usually caused by a range of factors. While heavy precipitation events can be caused by dynamic and/or thermodynamic processes, floods occur only partly as a response to heavy precipitation. Depending on the catchment, they can be largely due to soil properties and conditions of the previous months. Probabilistic attribution studies are multidisciplinary and therefore all aspects need to be communicated properly.

  15. Anthropogenic radionuclides in the Arctic Ocean. Distribution and pathways

    International Nuclear Information System (INIS)

    Anthropogenic radionuclide concentrations have been determined in seawater and sediment samples collected in 1991, 1994 and 1996 in the Eurasian Arctic shelf and interior. Global fallout, releases from European reprocessing plants and the Chernobyl accident are identified as the three main sources. From measurements in the Eurasian shelf seas it is concluded that the total input of 134Cs, 137Cs and 90Sr from these sources has been decreasing during the 1990's, while 129I has increased. The main fraction of the reprocessing and Chernobyl activity found in Arctic Ocean surface layer is transported from the Barents Sea east along the Eurasian Arctic shelf seas to the Laptev Sea before entering the Nansen Basin. This inflow results in highest 137Cs, 129I and 90Sr concentrations in the Arctic Ocean surface layers, and continuously decreasing concentrations with depth. Chernobyl-derived 137Cs appeared in the central parts of the Arctic Ocean around 1991, and in the mid 1990's the fraction to total 137Cs was approximately 30% in the entire Eurasian Arctic region. The transfer times for releases from Sellafield are estimated to be 5-7 years to the SE Barents Sea, 7-9 years to the Kara Sea, 10-11 years to the Laptev Sea and 12-14 years to the central Arctic Ocean. Global fallout is the primary source of plutonium with highest concentrations found in the Atlantic layer of the Arctic Ocean. When transported over the shallow shelf seas, particle reactive transuranic elements experience an intense scavenging. A rough estimate shows that approximately 75% of the plutonium entering the Kara and Laptev Seas are removed to the sediment. High seasonal riverine input of 239, 240Pu is observed near the mouths of the large Russian rivers. Sediment inventories show much higher concentrations on the shelf compared to the deep Arctic Ocean. This is primarily due to the low particle flux in the open ocean

  16. Anthropogenic gadolinium as a microcontaminant in tap water used as drinking water in urban areas and megacities

    International Nuclear Information System (INIS)

    Gadolinium chelates have been used since 1988 as contrast agents in magnetic resonance imaging (MRI), and produce positive anthropogenic Gd anomalies in rare earth element (REE) patterns of river and lake waters. These Gd compounds are not removed in wastewater treatment plants (WWTP) due to their high stabilities, and are transferred to surface waters with the clearwater discharge from WWTP. Through natural and induced bank filtration, the anthropogenic Gd is also transported into groundwater. To date, there are no related acute health risks known, but the potential long-term effects of exposure to low doses have not been studied. Here REE data is presented for tap water from the City of Berlin, Germany, a metropolitan area that is known for its anthropogenic Gd-rich rivers and groundwater. Natural and induced bank filtration play important roles in Berlin’s freshwater resource management. Therefore, the extent to which municipal tap water that is used as drinking water is affected by anthropogenic Gd was investigated. Large positive Gd anomalies were found in tap water samples from the western districts of Berlin, indicating the presence of up to 18 ng/L of anthropogenic Gd on top of a geogenic background of 0.54 ng/L. In marked contrast, the amount of anthropogenic Gd in tap water from the eastern districts of Berlin is negligible to minor (maximum of 0.18 ng/L on top of a geogenic background of 0.26 ng/L). This strong regional difference likely results from the specific historical situation of Berlin, where before the re-unification of Germany in 1990, natural and induced bank filtration were necessities in isolated West Berlin, but unimportant in East Berlin, a situation that has seen little change during the past 20 years. Thus, drinking water resources in the western part of Berlin are more strongly affected by anthropogenic Gd than those in the eastern part. The high anthropogenic Gd concentrations found in some tap waters in Berlin clearly show that the

  17. Spatial distribution of organic and pyritic sulfur in surface sediments of eutrophic Jiaozhou Bay, China: clues to anthropogenic impacts.

    Science.gov (United States)

    Chen, Ke-Ke; Zhu, Mao-Xu; Yang, Gui-Peng; Fan, De-Jiang; Huang, Xiang-Li

    2014-11-15

    Anthropogenic perturbations exert important impacts on sulfur geochemistry in marine sediments. In the study, chemical extraction was used to quantify four sulfur pools, i.e., pyrite, humic-acid sulfur (HA-S), fulvic-acid sulfur (FA-S), and residual organic sulfur (ROS), in surface sediments of eutrophic Jiaozhou Bay. Results show that riverine inputs are the main control on organic matter (OM) distribution in the sediments. OM enrichment in the eastern coast is mainly due to discharges of anthropogenic wastes. Spatial coupling of pyrite and FA-S vs. TOC points to the impacts of OM enrichment on formation and preservation of pyrite and FA-S. Poor spatial coupling of HA-S vs. TOC is due to low fractions of diagenetic OS in the pool. ROS is mainly from riverine inputs and anthropogenic OS has been superimposed on this pool. Spatial coupling among TOC, pyrite-S and FA-S is a sensitive indicator of anthropogenic impacts on benthic processes of the bay. PMID:25220315

  18. Characterizing anthropogenic sources of pollution and their influence on regional air quality and meteorology during the VOCALS-REX experiment

    Science.gov (United States)

    Mena-Carrasco, M.; Carmichael, G. R.; Spak, S.; Molina, L. T.; Saide, P.

    2010-12-01

    During the VOCALS REX campaign multiple anthropogenic sources of aerosol (both primary and secondary) were related to small effective radii of cloud droplets observed both in situ, and from satellite sources. Also enhanced concentrations of secondary pollutants such as ozone and sulfate were observed. Some of these sources come from copper smelters, power plants, and large urban areas. These impacts on the properties of marine stratocumulus is relevant on the region's radiative balance. For this project the contribution of urban, industrial, and power sector emissions will be compared to attribute these to observed values using WRF-Chem using a new Chilean National Emissions Inventory developed for this project. Finally regional ozone formation from Santiago and it's impact to observed enhancements off the coast of Northern Chile will be assessed. Modeled plumes will be compared to satellite observations of anthropogenic impacted clouds. Considering the projected increase of coal power plants in northern Chile, some projected impacts will also be shown.

  19. Detecting anthropogenic climate change with an optimal fingerprint method

    International Nuclear Information System (INIS)

    We propose a general fingerprint strategy to detect anthropogenic climate change and present application to near surface temperature trends. An expected time-space-variable pattern of anthropogenic climate change (the 'signal') is identified through application of an appropriate optimally matched space-time filter (the 'fingerprint') to the observations. The signal and the fingerprint are represented in a space with sufficient observed and simulated data. The signal pattern is derived from a model-generated prediction of anthropogenic climate change. Application of the fingerprint filter to the data yields a scalar detection variable. The statistically optimal fingerprint is obtained by weighting the model-predicted pattern towards low-noise directions. A combination of model output and observations is used to estimate the noise characteristics of the detection variable, arising from the natural variability of climate in the absence of external forcing. We test then the null hypothesis that the observed climate change is part of natural climate variability. We conclude that a statistically significant externally induced warming has been observed, with the caveat of a possibly inadequate estimate of the internal climate variability. In order to attribute this warming uniquely to anthropogenic greenhouse gas forcing, more information on the climate's response to other forcing mechanisms (e.g. changes in solar radiation, volcanic or anthropogenic aerosols) and their interaction is needed. (orig./KW)

  20. Anthropogenic radionuclides in Ottawa River sediment near Chalk River Laboratories

    International Nuclear Information System (INIS)

    The Ottawa River has received nuclear reactor effluent from Chalk River Laboratories (CRL) for more than 60 years, including releases from a NRX accident in 1952. Recent interest in the potential impact of these historical releases and the possible need for remediation of a small region immediately downstream from the release point has led to comprehensive studies to assess risk to people and wildlife. In this paper, the results of an extensive survey of gamma-emitting anthropogenic radionuclides in Ottawa River sediment in the vicinity of CRL are presented. Anthropogenic radionuclides detected in Ottawa River sediment include 60Co, 94Nb, 137Cs, 152Eu, 154Eu, 155Eu and 241Am. Concentrations of all anthropogenic radionuclides decline rapidly with distance downstream of the process outfall, reaching stable concentrations about 2 km downstream. All of these radionuclides are found at some sites within 2 km upstream of the process outfall suggesting limited upstream transport and sedimentation. Comparison of anthropogenic radionuclides with several representative primordial radionuclides shows that with the exception of sites at the process outfall and within 2 km downstream of the process outfall, primordial radionuclide concentrations greatly exceed CRL derived anthropogenic radionuclide concentrations. Thus, over 60 years of radionuclide releases from operations at CRL have had little impact on radionuclide concentrations in Ottawa River sediment, except at a few sites immediately adjacent to the process outfall. (author)

  1. Detecting anthropogenic climate change with an optimal fingerprint method

    Energy Technology Data Exchange (ETDEWEB)

    Hegerl, G.C. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Storch, H. von [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Hasselmann, K. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Santer, B.D. [Lawrence Livermore National Lab., CA (United States). Program for Climate Model Diagnosis and Intercomparison; Cubasch, U. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Jones, P.D. [East Anglia Univ., Norwich (United Kingdom). Climatic Research Unit

    1994-09-01

    We propose a general fingerprint strategy to detect anthropogenic climate change and present application to near surface temperature trends. An expected time-space-variable pattern of anthropogenic climate change (the `signal`) is identified through application of an appropriate optimally matched space-time filter (the `fingerprint`) to the observations. The signal and the fingerprint are represented in a space with sufficient observed and simulated data. The signal pattern is derived from a model-generated prediction of anthropogenic climate change. Application of the fingerprint filter to the data yields a scalar detection variable. The statistically optimal fingerprint is obtained by weighting the model-predicted pattern towards low-noise directions. A combination of model output and observations is used to estimate the noise characteristics of the detection variable, arising from the natural variability of climate in the absence of external forcing. We test then the null hypothesis that the observed climate change is part of natural climate variability. We conclude that a statistically significant externally induced warming has been observed, with the caveat of a possibly inadequate estimate of the internal climate variability. In order to attribute this warming uniquely to anthropogenic greenhouse gas forcing, more information on the climate`s response to other forcing mechanisms (e.g. changes in solar radiation, volcanic or anthropogenic aerosols) and their interaction is needed. (orig./KW)

  2. Anthropogenic structures in the geosystems (landscapes) of the permafrost zone

    International Nuclear Information System (INIS)

    Problems created by oil and gas field development in Arctic regions attract much attention in the discussion of the interaction of civil and industrial buildings and structures with permafrost. The investigations carried out must permit the evaluation of changes in the natural environment and single out the anthropogenic component of these changes, must ensure accident-free operation of oil and gas transport units, safety of people and environmental control in the mineral resource production regions of the Arctic. Taking the pipeline-environment system example, this report characterizes the spatial-temporal structure of the gas transport geotechnical system as a natural-anthropogenic, physico-geographical object. The natural sub-system of this object consists of several structures (referred to as areas and zones). These structures are characterized by different dynamics of regeneration processes of anthropogenic disturbances. It is found that the most negative ecological consequences during the development of the regions at the boundary of tundra and forest-tundra are associated with the disturbances of pre-tundra forests. The least perceptible ecological changes are typical for anthropogenic transformation of bog geo-systems. The anthropogenic structures, which are formed here, are characterized by a state most similar to the initial conditions and, often, by an increase of biomass in the landscapes. All these data are presented according to the author's investigations in the permafrost zone of Western Siberia

  3. Anthropogenic structures in the geosystems (Landscapes) of the permafrost zone

    International Nuclear Information System (INIS)

    Problems created by oil and gas field development in Arctic regions attract much attention in the discussion of the interaction of civil and industrial buildings and structures with permafrost. The investigations carried out must permit the evaluation of changes in the natural environment and single out the anthropogenic component of these changes, must ensure accident-free operation of oil and gas transport units, safety of people and environmental control in the mineral resource production regions of the Arctic. Taking the pipeline-environment system example, this report characterizes the spatial-temporal structure of the gas transport geotechnical system as a natural-anthropogenic, physico-geographical object. The natural subsystem of this object consists of several structures (referred to as areas and zones). These structures are characterized by different dynamics of regeneration processes of anthropogenic disturbances. It is found that the most negative ecological consequences during the development of the regions at the boundary of tundra and forest-tundra are associated with the disturbances of pre-tundra forests. The least perceptible ecological changes are typical for anthropogenic transformation of bog geo-systems. The anthropogenic structures, which are formed here, are characterized by a state most similar to the initial conditions and, often, by an increase of biomass in the landscapes. All these data are presented according to the author's investigations in the permafrost zone of Western Siberia

  4. Red mangrove life history variables along latitudinal and anthropogenic stress gradients.

    Science.gov (United States)

    Proffitt, C Edward; Travis, Steven

    2014-06-01

    Mangroves migrate northward in Florida and colonize marshes historically dominated by salt marsh species. In theory, this migration should be facilitated by greater numbers of propagules stemming from increased reproductive activity and greater genetic variability caused by outcrossing. We aimed to determine if stand reproduction and % outcrossing were affected by cold stress (stress increases with latitude), anthropogenic stress (human population density as a proxy), and years since a major hurricane. Further, we wished to determine if mutation rate varied with the stressors and if that affected stand reproduction. Both coasts of Florida from the southern Florida Keys to Tampa Bay on the Gulf of Mexico coast, and Merritt Island on the Atlantic coast. We conducted field surveys of frequency of reproducing trees (104,211 trees surveyed in 102 forested stands), incidence of trees showing albinism in propagules, and% outcrossing estimated from the ratio of albino:normal propagules. Structural equation modeling (SEM) was used to test a conceptual model that served as a multivariate hypothesis. Reproductive frequencies varied by site and increased with latitude although more strongly on the Gulf coast. Our SEM results indicate that outcrossing increases in this predominately selfing species under conditions of cold and anthropogenic stress, and that this increases reproductive output in the population. Further, we find that increased mutation rates suppress stand reproductive output but there is no significant relationship between outcrossing and mutation rate. Tree size responded to stressors but did not affect stand reproduction. Reproduction increased with years since major hurricane. Potential for colonization of northern Florida salt marshes by mangroves is enhanced by increased reproductive rates that provides more propagules and outcrossing that should enhance genetic variation thereby promoting adaptation to novel environmental conditions. Natural (cold) stress

  5. Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California.

    Science.gov (United States)

    Mann, Michael L; Batllori, Enric; Moritz, Max A; Waller, Eric K; Berck, Peter; Flint, Alan L; Flint, Lorraine E; Dolfi, Emmalee

    2016-01-01

    The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state's fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change. PMID:27124597

  6. Incorporating Anthropogenic Influences into Fire Probability Models: Effects of Human Activity and Climate Change on Fire Activity in California

    Science.gov (United States)

    Batllori, Enric; Moritz, Max A.; Waller, Eric K.; Berck, Peter; Flint, Alan L.; Flint, Lorraine E.; Dolfi, Emmalee

    2016-01-01

    The costly interactions between humans and wildfires throughout California demonstrate the need to understand the relationships between them, especially in the face of a changing climate and expanding human communities. Although a number of statistical and process-based wildfire models exist for California, there is enormous uncertainty about the location and number of future fires, with previously published estimates of increases ranging from nine to fifty-three percent by the end of the century. Our goal is to assess the role of climate and anthropogenic influences on the state’s fire regimes from 1975 to 2050. We develop an empirical model that integrates estimates of biophysical indicators relevant to plant communities and anthropogenic influences at each forecast time step. Historically, we find that anthropogenic influences account for up to fifty percent of explanatory power in the model. We also find that the total area burned is likely to increase, with burned area expected to increase by 2.2 and 5.0 percent by 2050 under climatic bookends (PCM and GFDL climate models, respectively). Our two climate models show considerable agreement, but due to potential shifts in rainfall patterns, substantial uncertainty remains for the semiarid inland deserts and coastal areas of the south. Given the strength of human-related variables in some regions, however, it is clear that comprehensive projections of future fire activity should include both anthropogenic and biophysical influences. Previous findings of substantially increased numbers of fires and burned area for California may be tied to omitted variable bias from the exclusion of human influences. The omission of anthropogenic variables in our model would overstate the importance of climatic ones by at least 24%. As such, the failure to include anthropogenic effects in many models likely overstates the response of wildfire to climatic change. PMID:27124597

  7. Childhood asthma and anthropogenic CO2 emissions

    OpenAIRE

    Dosanjh A

    2011-01-01

    Amrita DosanjhPediatric Pulmonologist, San Diego, California, USATrends in the incidence of childhood asthma worldwide have paralleled the sharp increase in carbon dioxide (CO2) emissions, over at least the last two decades. The prevalence of asthma in the United States has quadrupled over the last 20 years in part due to climate-related factors. In a report released by Harvard Medical School and the Center for Health and the Global Environment, it was noted that there was an increase in asth...

  8. Effects of anthropogenic particles on the chemical and geophysical properties of urban soils, Detroit, Michigan

    Science.gov (United States)

    Orlicki, Katharine M.

    There is a great need in many cities for a better quality of urban soil maps. This is due to the increasing interest in repurposing vacant land for urban redevelopment, agriculture, and green infrastructure. Mapping vacant urban land in Detroit can be very difficult because anthropogenic soils were often highly variable and frequently contained demolition debris (such as brick), making it difficult to use a hand auger. This study was undertaken in Detroit, MI to create a more efficient way to map urban soils based on their geophysical and chemical properties. This will make the mapping process faster, less labor intensive, and therefore more cost effective. Optical and chemical criteria for the identification and classification of microartifacts (MAs) were made from a set of reference artifacts of a known origin. These MAs were then observed and tested in urban topsoil samples from sites in Detroit, Michigan that represent three different land use types (residential demolition, fly ash-impacted, and industrial). Optical analyses, SEM, EDAX, and XRD showed that reference MAs may be classified into five basic compositional types (carbonaceous, calcareous, siliceous, ferruginous and miscellaneous). Reference MAs were generally distinguishable using optical microscopy by color, luster, fracture and microtexture. MAs that were more difficult to classify were further differentiable when using SEM, EDAX, and XRD. MAs were found in all of the anthropogenic soils studied, but were highly variable. All three study sites had concentrations coal-related wastes were the most common types of MAs observed and often included coal, ash (microspheres, microagglomerate), cinders, and burnt shale. MAs derived from waste building materials such as brick, mortar, and glass, were typically found on residential demolition sites. Manufacturing waste MAs, which included iron-making slag and coked coal were commonly observed on industrial sites. Fly ash-impacted sites were composed of only

  9. Nitrogen isotopes in ice core nitrate linked to anthropogenic atmospheric acidity change

    OpenAIRE

    Geng, Lei; Alexander, Becky; Cole-Dai, Jihong; Steig, Eric J.; Savarino, Joël; Sofen, Eric D.; Schauer, Andrew J.

    2014-01-01

    The specific cause of the long-term decrease in stable nitrogen isotope ratio (15N/14N) of ice core nitrate beginning ∼1850 is a subject of debate, hindering the efforts to understand changes in the global nitrogen cycle. Our high-resolution record of ice core 15N/14N combined with model calculations suggests that the decrease is mainly caused by equilibrium shift in gas−particle partitioning of atmospheric nitrate due to increasing atmospheric acidity resulting from anthropogenic emissions o...

  10. Delivery of anthropogenic bioavailable iron from mineral dust and combustion aerosols to the ocean

    Science.gov (United States)

    Ito, A.; Shi, Z.

    2016-01-01

    Atmospheric deposition of anthropogenic soluble iron (Fe) to the ocean has been suggested to modulate primary ocean productivity and thus indirectly affect the climate. A key process contributing to anthropogenic sources of soluble Fe is associated with air pollution, which acidifies Fe-containing mineral aerosols during their transport and leads to Fe transformation from insoluble to soluble forms. However, there is large uncertainty in our estimate of this anthropogenic soluble Fe. In this study, for the first time, we interactively combined laboratory kinetic experiments with global aerosol modeling to more accurately quantify anthropogenic soluble Fe due to air pollution. Firstly, we determined Fe dissolution kinetics of African dust samples at acidic pH values with and without ionic species commonly found in aerosol water (i.e., sulfate and oxalate). Then, by using acidity as a master variable, we constructed a new empirical scheme for Fe release from mineral dust due to inorganic and organic anions in aerosol water. We implemented this new scheme and applied an updated mineralogical emission database in a global atmospheric chemistry transport model to estimate the atmospheric concentration and deposition flux of soluble Fe under preindustrial and modern conditions. Our improved model successfully captured the inverse relationship of Fe solubility and total Fe loading measured over the North Atlantic Ocean (i.e., 1-2 orders of magnitude lower Fe solubility in northern-African- than combustion-influenced aerosols). The model results show a positive relationship between Fe solubility and water-soluble organic carbon (WSOC)/Fe molar ratio, which is consistent with previous field measurements. We estimated that deposition of soluble Fe to the ocean increased from 0.05-0.07 Tg Fe yr-1 in the preindustrial era to 0.11-0.12 Tg Fe yr-1 in the present day, due to air pollution. Over the high-nitrate, low-chlorophyll (HNLC) regions of the ocean, the modeled Fe

  11. Anthropogenic influence on the frequency of extreme temperatures in China

    Science.gov (United States)

    Lu, Chunhui; Sun, Ying; Wan, Hui; Zhang, Xuebin; Yin, Hong

    2016-06-01

    Anthropogenic influence on the frequencies of warm days, cold days, warm nights, and cold nights are detected in the observations of Chinese temperature data covering 1958-2002. We used an optimal fingerprinting method to compare these temperature indices computed from a newly homogenized observational data set with those from simulations conducted with multiple climate models that participated in the Coupled Model Intercomparison Project Phase 5. We found the clear anthropogenic signals in the observational records of frequency changes in warm and cold days and nights. We also found that the models appear to be doing a better job in simulating the observed frequencies of daytime extremes than nighttime extremes. The model-simulated variability appears to be consistent with that of the observations, providing confidence on the detection results. Additionally, the anthropogenic signal can be clearly detected at subnational scales, with detectable human influence found in Eastern and Western China separately.

  12. Environmental and anthropogenic determinants of vegetation distribution across Africa

    DEFF Research Database (Denmark)

    Greve, Michelle; Lykke, Anne Mette; Overgaard, Anne Blach;

    2011-01-01

    Aim  To assess the influence of natural environmental factors and historic and current anthropogenic processes as determinants of vegetation distributions at a continental scale. Location  Africa. Methods  Boosted regression trees (BRTs) were used to model the distribution of African vegetation...... types, represented by remote-sensing-based land-cover (LC) types, as a function of environmental factors. The contribution of each predictor variable to the best models and the accuracy of all models were assessed. Subsequently, to test for anthropogenic vegetation transformation, the relationship...... between the number of BRT false presences per grid cell and human impact was evaluated using hurdle models. Finally, the relative contributions of environmental, current and historic anthropogenic factors on vegetation distribution were assessed using regression-based variation partitioning. Results...

  13. The Role of Anthropogenic Stratigraphy in River Restoration Projects

    Science.gov (United States)

    Evans, J. E.; Webb, L. D.

    2012-12-01

    As part of a river restoration project and removal of a low-head dam on the Ottawa River (northwestern Ohio and southeastern Michigan) in 2007, a longer-term project was initiated to assess anthropogenic changes of the Ottawa River fluvial system. A composite stratigraphic section 4.5 m in length was constructed by stratigraphic correlation from three trenches up to 2.5 m in depth and 14 vibracores up to 2.5 m in length, all within a small region (<0.5 km2 in area). At various stratigraphic levels, the cores contain a suite of anthropogenic materials including fragments of bricks and cement blocks, pieces of modern ceramics, fragments of plastic and rubber tires, intact or pieces of glass bottles, and one horizon of displaced railroad ties. Age control for the composite section is provided by 4 14C dates, 6 OSL dates, and one bottle with a date stamp. Two prominent flood horizons are indicated in multiple trenches or cores, and identified as the historic floods of 1913 and 1959. The data show the following major changes in the fluvial system over time: (1) prior to approximately 5 Ka, the river system was transporting mineral-rich sediment and formed meandering point-bar sequences approximately 1.5 m thick; (2) between approximately 5 Ka and 200 YBP, the river system was transporting organic-rich sediment (i.e., blackwater stream) bordered by riparian wetlands accumulating peat (part of the regional "Great Black Swamp" discovered by settlers from eastern North America); (3) between approximately 200 YBP and the early 1960s the river system was transporting mineral-rich sediment (i.e., brownwater stream), probably sourced from extensive land clearance for agriculture, which backfilled and overtopped the previous riparian wetlands and produced an series of thin channel fills interpreted as rapidly shifting avulsional channels; (4) since the early 1960s, sediment supply has exceeded sediment conveyance capacity, leading to vertical aggradation of approximately 1.7 m

  14. The invertebrate fauna of anthropogenic soils in the High-Arctic settlement of Barentsburg, Svalbard

    Directory of Open Access Journals (Sweden)

    Torstein Solhøy

    2013-05-01

    Full Text Available The terrestrial environment of the High Arctic consists of a mosaic of habitat types. In addition to the natural habitat diversity, various human-influenced types may occur. For the resident invertebrate fauna, these anthropogenic habitats may be either unusually favourable or detrimental. In the town of Barentsburg, Svalbard, soils were imported for the greenhouses from southern Russia. These soils were subsequently discarded outside the greenhouses and have become augmented with manure from the cowsheds. Both the greenhouse and the cowsheds are now derelict. This site represents an unusually nutrient-rich location with considerable development of organic soils, in stark contrast to the naturally forming organic soils in Svalbard, which are typically thin and nutrient poor. Few previous studies have examined the soil invertebrate communities of human-disturbed or -created habitats in the Arctic. In an often nutrient-poor terrestrial environment, it is unclear how the invertebrate fauna will react to such nutrient enhancement. In these soils, 46 species of invertebrates were determined. Eleven species have not been recorded from other habitats in Svalbard and are hence likely to have been introduced. The native species assemblage in the anthropogenic soils was not atypical for many natural sites in Svalbard. Despite the enriched organic soils and highly ameliorated winter temperature conditions, the soil invertebrate fauna biodiversity does not appear to be enhanced beyond the presence of certain probably introduced species.

  15. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes).

    Science.gov (United States)

    Carlitz, Esther H D; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C; van Schaik, Carel P

    2016-01-01

    Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species. PMID:27050418

  16. Anthropogenic forcing dominates sea level rise since 1850

    DEFF Research Database (Denmark)

    Jevrejeva, Svetlana; Grinsted, Aslak; Moore, John

    2009-01-01

    The rate of sea level rise and its causes are topics of active debate. Here we use a delayed response statistical model to attribute the past 1000 years of sea level variability to various natural (volcanic and solar radiative) and anthropogenic (greenhouse gases and aerosols) forcings. We show...... that until 1800 the main drivers of sea level change are volcanic and solar radiative forcings. For the past 200 years sea level rise is mostly associated with anthropogenic factors. Only 4 ± 1.5 cm (25% of total sea level rise) during the 20th century is attributed to natural forcings, the remaining...

  17. On Dangerous Anthropogenic Interference and Climate Change Risk (Invited)

    Science.gov (United States)

    Mann, M. E.

    2009-12-01

    The United Nations Framework Convention on Climate Change (UNFCCC) commits signatory nations (which includes all major nations including the United States) to stabilizing greenhouse gas concentrations at levels short of Dangerous Anthropogenic Interference (“ DAI”) with the climate. To properly define DAI, one must take into account issues that are not only scientific, but, economic, political, and ethical in nature. Defining DAI is furthermore complicated by the inter-generational and regionally-disaggregated nature of the risks associated with climate change. In this talk, I will explore the nature of anthropogenic climate change risks and the notion of DAI.

  18. Large Gain in Air Quality Compared to an Alternative Anthropogenic Emissions Scenario

    Science.gov (United States)

    Daskalakis, Nikos; Tsigaridis, Kostas; Myriokefalitakis, Stelios; Fanourgakis, George S.; Kanakidou, Maria

    2016-01-01

    During the last 30 years, significant effort has been made to improve air quality through legislation for emissions reduction. Global three-dimensional chemistrytransport simulations of atmospheric composition over the past 3 decades have been performed to estimate what the air quality levels would have been under a scenario of stagnation of anthropogenic emissions per capita as in 1980, accounting for the population increase (BA1980) or using the standard practice of neglecting it (AE1980), and how they compare to the historical changes in air quality levels. The simulations are based on assimilated meteorology to account for the yearto- year observed climate variability and on different scenarios of anthropogenic emissions of pollutants. The ACCMIP historical emissions dataset is used as the starting point. Our sensitivity simulations provide clear indications that air quality legislation and technology developments have limited the rapid increase of air pollutants. The achieved reductions in concentrations of nitrogen oxides, carbon monoxide, black carbon, and sulfate aerosols are found to be significant when comparing to both BA1980 and AE1980 simulations that neglect any measures applied for the protection of the environment. We also show the potentially large tropospheric air quality benefit from the development of cleaner technology used by the growing global population. These 30-year hindcast sensitivity simulations demonstrate that the actual benefit in air quality due to air pollution legislation and technological advances is higher than the gain calculated by a simple comparison against a constant anthropogenic emissions simulation, as is usually done. Our results also indicate that over China and India the beneficial technological advances for the air quality may have been masked by the explosive increase in local population and the disproportional increase in energy demand partially due to the globalization of the economy.

  19. Large gain in air quality compared to an alternative anthropogenic emissions scenario

    Science.gov (United States)

    Daskalakis, Nikos; Tsigaridis, Kostas; Myriokefalitakis, Stelios; Fanourgakis, George S.; Kanakidou, Maria

    2016-08-01

    During the last 30 years, significant effort has been made to improve air quality through legislation for emissions reduction. Global three-dimensional chemistry-transport simulations of atmospheric composition over the past 3 decades have been performed to estimate what the air quality levels would have been under a scenario of stagnation of anthropogenic emissions per capita as in 1980, accounting for the population increase (BA1980) or using the standard practice of neglecting it (AE1980), and how they compare to the historical changes in air quality levels. The simulations are based on assimilated meteorology to account for the year-to-year observed climate variability and on different scenarios of anthropogenic emissions of pollutants. The ACCMIP historical emissions dataset is used as the starting point. Our sensitivity simulations provide clear indications that air quality legislation and technology developments have limited the rapid increase of air pollutants. The achieved reductions in concentrations of nitrogen oxides, carbon monoxide, black carbon, and sulfate aerosols are found to be significant when comparing to both BA1980 and AE1980 simulations that neglect any measures applied for the protection of the environment. We also show the potentially large tropospheric air quality benefit from the development of cleaner technology used by the growing global population. These 30-year hindcast sensitivity simulations demonstrate that the actual benefit in air quality due to air pollution legislation and technological advances is higher than the gain calculated by a simple comparison against a constant anthropogenic emissions simulation, as is usually done. Our results also indicate that over China and India the beneficial technological advances for the air quality may have been masked by the explosive increase in local population and the disproportional increase in energy demand partially due to the globalization of the economy.

  20. Anthropogenic climate change affects meteorological drought risk in Europe

    International Nuclear Information System (INIS)

    Drought constitutes a significant natural hazard in Europe, impacting societies and ecosystems across the continent. Climate model simulations with increasing greenhouse gas concentrations project increased drought risk in southern Europe, and on the other hand decreased drought risk in the north. Observed changes in water balance components and drought indicators resemble the projected pattern. However, assessments of possible causes of the reported regional changes have so far been inconclusive. Here we investigate whether anthropogenic emissions have altered past and present meteorological (precipitation) drought risk. For doing so we first estimate the magnitude of 20 year return period drought years that would occur without anthropogenic effects on the climate. Subsequently we quantify to which degree the occurrence probability, i.e. the risk, of these years has changed if anthropogenic climate change is accounted for. Both an observational and a climate model-based assessment suggest that it is >95% likely that human emissions have increased the probability of drought years in the Mediterranean, whereas it is >95% likely that the probability of dry years has decreased in northern Europe. In central Europe the evidence is inconclusive. The results highlight that anthropogenic climate change has already increased drought risk in southern Europe, stressing the need to develop efficient mitigation measures. (letter)

  1. Environmental challenges of anthropogenic metals flows and cycles

    DEFF Research Database (Denmark)

    van der Voet, Ester; Salminen, Reijo; Eckelman, Matthew;

    This report from the UNEP-hosted International Resource Panel, Environmental Risk and Challenges of Anthropogenic Metals Flows and Cycles, gives a clear picture of the potential environmental impacts of metals at different stages of the life-cycle while linking with other areas of resource use such...

  2. Anthropogenic climate change affects meteorological drought risk in Europe

    Science.gov (United States)

    Gudmundsson, L.; Seneviratne, S. I.

    2016-04-01

    Drought constitutes a significant natural hazard in Europe, impacting societies and ecosystems across the continent. Climate model simulations with increasing greenhouse gas concentrations project increased drought risk in southern Europe, and on the other hand decreased drought risk in the north. Observed changes in water balance components and drought indicators resemble the projected pattern. However, assessments of possible causes of the reported regional changes have so far been inconclusive. Here we investigate whether anthropogenic emissions have altered past and present meteorological (precipitation) drought risk. For doing so we first estimate the magnitude of 20 year return period drought years that would occur without anthropogenic effects on the climate. Subsequently we quantify to which degree the occurrence probability, i.e. the risk, of these years has changed if anthropogenic climate change is accounted for. Both an observational and a climate model-based assessment suggest that it is >95% likely that human emissions have increased the probability of drought years in the Mediterranean, whereas it is >95% likely that the probability of dry years has decreased in northern Europe. In central Europe the evidence is inconclusive. The results highlight that anthropogenic climate change has already increased drought risk in southern Europe, stressing the need to develop efficient mitigation measures.

  3. Environmental challenges of anthropogenic metals flows and cycles

    OpenAIRE

    van der Voet, Ester; Salminen, Reijo; Eckelman, Matthew; Norgate, Terry; Mudd, Gavin; Hisschier, Roland; Spijker, Job; Vijver, Martina; Selinus, Olle; Posthuma, Leo; de Zwart, Dick; Meent, Dik van de; Reuter, Markus; Tikana, Ladji; Valdivia, Sonia

    2013-01-01

    This report from the UNEP-hosted International Resource Panel, Environmental Risk and Challenges of Anthropogenic Metals Flows and Cycles, gives a clear picture of the potential environmental impacts of metals at different stages of the life-cycle while linking with other areas of resource use such as water, food production and energy.

  4. Radiological environmental study in area to future anthropogenic transformations

    International Nuclear Information System (INIS)

    In this work the existent relationship is identified between the data radioecologics and the geological formations to the north area Holguin with the objective to study the possible incidence that this can have in the rate environmental dose in the event of transformations anthropogenic the place

  5. Intercalibration of selected anthropogenic radionuclides for the GEOTRACES Program

    DEFF Research Database (Denmark)

    Kenna, Timothy C.; Masqué, Pere; Mas, Jose Luis;

    2012-01-01

    As part of the GEOTRACES Program, six laboratories participated in an intercalibration exercise on several anthropogenic radionuclides of interest. The effort was successful for 239,240Pu activity, 240Pu/239Pu isotope ratio, and 137Cs activity measured in filtered seawater samples from the Bermuda...

  6. Anthropogenic accumulation of metals and metalloids in carbonate-rich sediments: Insights from the ancient harbor setting of Tyre (Lebanon)

    Science.gov (United States)

    Elmaleh, A.; Galy, A.; Allard, T.; Dairon, R.; Day, J. A.; Michel, F.; Marriner, N.; Morhange, C.; Couffignal, F.

    2012-04-01

    The Antique and Byzantine sediments of the northern harbor of Tyre (Lebanon) store high amounts of metals and metalloids as the result of a millennial anthropogenic contamination as well as of efficient trapping and immobilization processes. Geochemical and mineralogical analyses reveal the contrasted patterns for the accumulation of trace metal(loid)s in the sedimentary sequence recovered by coring the inner part, now emerged, of the ancient harbor. Lead, Sn, Cu and Ag concentrations can be as high as 3000, 150, 1000, and 1.2 μg/g, respectively. Enrichment factors were calculated with respect to (1) Th and (2) the chemistry of the substratum and appear to be driven by anthropogenic inputs. Indeed, a drastic change in both excess concentrations and concentration ratios is observed through Roman and Byzantine times, pointing to major intensification of the trade and use of metals in Tyre, coherent with historical data. Good preservation of the archeological signal, despite (1) sediment disturbances that have caused age depth inversions, and (2) the large time lapse since the time of deposition of anthropogenic trace metal(loid)s is probably due to the reducing character of the sediments. Tyre's sedimentary sequence provides an interesting analog for modern carbonate-rich harbor environments, in which a millenary accumulation of trace metal(loid)s has been overall well preserved and suggests a restricted mobility of anthropogenic contamination for a period of time in excess of 1500 years.

  7. Anthropogenic Disturbance of Element Cycles at the Earth's Surface

    Science.gov (United States)

    Sen, I. S.; Peucker-Ehrenbrink, B.

    2012-12-01

    The extent to which humans are modifying Earth's surface chemistry can be quantified by comparing total anthropogenic element fluxes with their natural counterparts [1]. We determine anthropogenic mass transfer of 77 elements from mining, fossil fuel burning, biomass burning, construction activities, and human apportionment of terrestrial net primary productivity, and compared it to natural mass transfer from terrestrial and marine net primary productivity, riverine dissolved and suspended matter fluxes to the ocean, soil erosion, eolian dust, sea-salt spray, cosmic dust, volcanic emissions and - for helium - hydrodynamic escape from the Earth's atmosphere. In addition, we introduce an approach to correct for losses during industrial processing of elements belonging to geochemically coherent groups, and explicitly incorporated uncertainties of element mass fluxes through Monte Carlo simulations [2]. Our assessment indicates that anthropogenic fluxes of iridium, osmium, helium, gold, ruthenium, antimony, platinum, palladium, rhenium, rhodium and chromium are greater than the respective natural fluxes. For these elements mining is the major factor of human dominance, whereas petroleum burning strongly influence the surficial cycle of rhenium. Apart from these 11 elements there are 15 additional elements whose anthropogenic fluxes may surpass their corresponding natural fluxes. Anthropogenic fluxes of the remaining elements are smaller than their corresponding natural fluxes although a significant human influence is observed for all of them. For example, ~20% of the annual fluxes of C, N, and P can be attributed to human activities. Such disturbances, though small compared with natural fluxes, can significantly alter concentrations in near-surface reservoirs and affect ecosystems if they are sustained over time scales similar to or longer than the residence time of elements in the respective reservoir. Examples are the continuing input of CO2 to the atmosphere that

  8. Anthropogenic radionuclides in the Arctic Ocean. Distribution and pathways

    Energy Technology Data Exchange (ETDEWEB)

    Josefsson, Dan

    1998-05-01

    Anthropogenic radionuclide concentrations have been determined in seawater and sediment samples collected in 1991, 1994 and 1996 in the Eurasian Arctic shelf and interior. Global fallout, releases from European reprocessing plants and the Chernobyl accident are identified as the three main sources. From measurements in the Eurasian shelf seas it is concluded that the total input of {sup 134}Cs, {sup 137}Cs and {sup 90}Sr from these sources has been decreasing during the 1990`s, while {sup 129}I has increased. The main fraction of the reprocessing and Chernobyl activity found in Arctic Ocean surface layer is transported from the Barents Sea east along the Eurasian Arctic shelf seas to the Laptev Sea before entering the Nansen Basin. This inflow results in highest {sup 137}Cs, {sup 129}I and {sup 90}Sr concentrations in the Arctic Ocean surface layers, and continuously decreasing concentrations with depth. Chernobyl-derived {sup 137}Cs appeared in the central parts of the Arctic Ocean around 1991, and in the mid 1990`s the fraction to total {sup 137}Cs was approximately 30% in the entire Eurasian Arctic region. The transfer times for releases from Sellafield are estimated to be 5-7 years to the SE Barents Sea, 7-9 years to the Kara Sea, 10-11 years to the Laptev Sea and 12-14 years to the central Arctic Ocean. Global fallout is the primary source of plutonium with highest concentrations found in the Atlantic layer of the Arctic Ocean. When transported over the shallow shelf seas, particle reactive transuranic elements experience an intense scavenging. A rough estimate shows that approximately 75% of the plutonium entering the Kara and Laptev Seas are removed to the sediment. High seasonal riverine input of {sup 239}, {sup 240}Pu is observed near the mouths of the large Russian rivers. Sediment inventories show much higher concentrations on the shelf compared to the deep Arctic Ocean. This is primarily due to the low particle flux in the open ocean

  9. Influence of natural factors and anthropogenic stressors on sperm whale foraging effort and success at high latitudes

    OpenAIRE

    Isojunno, Saana

    2015-01-01

    Behavioural responses can reveal important fitness trade-offs and ecological traps in evolutionarily novel contexts created by anthropogenic stimuli, and are of increasing conservation concern due to possible links to population-level impacts. This thesis illustrates the use of proxies for energy acquisition and expenditure within multivariate and state-based modelling approaches to quantify the relative time and energetic costs of behavioural disturbance for a deep-diving marine mammal (Phys...

  10. Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes)

    Science.gov (United States)

    Carlitz, Esther H. D.; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C.; van Schaik, Carel P.

    2016-01-01

    Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p nests [F(2,178) = 20.3, p chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species. PMID:27050418

  11. Projected effects of declining anthropogenic aerosols on the southern annular mode

    International Nuclear Information System (INIS)

    Declining emissions of anthropogenic aerosols have been shown to contribute to global warming in climate projections from the Coupled Model Intercomparison Project Phase 5 (CMIP5). This study considers the response of the southern annular mode (SAM) in austral summer to declining aerosols in simulations forced by Representative Concentration Pathway 4.5 (RCP4.5) using CSIRO-Mk3.6, a CMIP5-generation model. A ten-member ensemble forced by RCP4.5 for the period 2006–2100 is compared with another experiment, which is identical except that emissions of anthropogenic aerosols are held fixed at their 2005 values. With fixed aerosol emissions, the model simulates a negative (but statistically insignificant) ensemble-mean SAM trend in austral summer, suggesting that the effects of recovering stratospheric ozone slightly outweigh the effects of increasing long-lived greenhouse gases (GHGs). In contrast, the standard RCP4.5 experiment (including additional warming due to declining aerosols) simulates a positive ensemble-mean SAM trend, and the difference between the two trends is significant at 5%. The response of Southern Hemisphere zonal-mean atmospheric circulation and temperature to declining aerosols resembles the response to increasing GHGs; this suggests that the positive SAM trend due to declining aerosols may be driven by mechanisms that are similar to those that cause the positive SAM trend in response to increasing GHGs. (letter)

  12. Natural and anthropogenic sources of chemical elements in sediment profiles from the Admiralty Bay, Antarctica

    International Nuclear Information System (INIS)

    Full text: The Antarctic Continent and its surrounding Southern Ocean are the least known regions of the world, mainly due to the most unfavorable climatic conditions, in which sampling for environmental studies are quite difficult to be carried out. Admiralty Bay on the King George Island (Antarctica) hosts three research stations, Arctowski, Ferraz and Macchu Picchu, which are operate by Poland, Brazil and Peru, respectively. Therefore, human activities in this region require the use of fossil fuel as an energy source, which is also considered the main source of pollutants in the area. This work investigated the natural and anthropogenic inputs of chemical elements in sediment samples collected close to Ferraz Station, during the 25th Brazilian Antarctica Expedition in the 2006/2007 austral summer. Total concentrations of As, Zn and Sc were determined in sediment profiles by using the Instrumental Neutron Activation Analysis (INAA). The analytical technique employed to determine the major elements such as Fe, Al, Ca, Mn and Ti was X-ray fluorescence (XRF) spectroscopy. For estimating the sedimentation rate, High Resolution Gamma Ray Spectrometry was applied to determine 137Cs, after 30 days, to achieve secular equilibrium. According to the enrichment factor and the geochronology analysis, the most relevant enrichment was observed for As in the sediment samples, suggesting the increasing of its content due to the Brazilian activities in the Admiralty Bay. Despite some evidences of anthropogenic contribution, the study indicated low level of environmental risk for this region. (author)

  13. Preliminary field study of hepatic porphyrin profiles of Astyanax fasciatus (Teleostei, Characiformes) to define anthropogenic pollution.

    Science.gov (United States)

    Carrasco-Letelier, Leonidas; Eguren, Gabriela; de Mello, Franco Teixeira; Groves, Phillip A

    2006-03-01

    The implementation of eco-toxicological assessment in South America is presently limited due to significant scientific information gaps concerning native species and their potential use as biomarkers. Recently, a common southern hemisphere fish species, Astyanax fasciatus, has been pointed out as a potential bio-indicator to anthropogenic pollution. This is a small, abundant, Neotropical characid, which is widely distributed from Central America south, to the Rio de la Plata Basin of western Uruguay. Our study found a statistically significant increase of coproporphyrin, uroporphyrin and protoporphyrin concentrations in hepatic tissues of A. fasciatus collected from a stream segment with high anthropogenic disturbance (due mainly to agricultural derivatives and motor vehicle transportation activities). Although the area studied showed differences in up and downstream limno-chemical parameters, these differences were not related to the increase of hepatic porphyrin concentrations. Based on the results of our study, we conclude that A. fasciatus is a good bio-indicator of exposure to environmental contaminants, and we propose that this abundant fish species be considered as a sentinel organism for monitoring potential disturbances to freshwater ecosystems. PMID:16153685

  14. Transport of anthropogenic and biomass burning aerosols from Europe to the Arctic during spring 2008

    Directory of Open Access Journals (Sweden)

    L. Marelle

    2014-11-01

    Full Text Available During the POLARCAT-France airborne campaign in April 2008, pollution originating from anthropogenic and biomass burning emissions was measured in the European Arctic. We compare these aircraft measurements with simulations using the WRF-Chem model to investigate model representation of aerosols transported from Europe to the Arctic. Modeled PM2.5 is evaluated using EMEP measurements in source regions and POLARCAT aircraft measurements in the Scandinavian Arctic, showing a good agreement, although the model overestimates nitrate and underestimates organic carbon in source regions. Using WRF-Chem in combination with the Lagrangian model FLEXPART-WRF, we find that during the campaign the research aircraft sampled two different types of European plumes: mixed anthropogenic and fire plumes from eastern Europe and Russia transported below 2 km, and anthropogenic plumes from central Europe uplifted by warm conveyor belt circulations to 5–6 km. Both modeled plume types had significant wet scavenging (> 50% PM10 during transport. Modeled aerosol vertical distributions and optical properties below the aircraft are evaluated in the Arctic using airborne LIDAR measurements. Evaluating the regional impacts in the Arctic of this event in terms of aerosol vertical structure, we find that during the 4 day presence of these aerosols in the lower European Arctic (2.5, modeled black carbon and SO4= concentrations are more enhanced near the surface. The European plumes sampled during POLARCAT-France were transported over the region of springtime snow cover in Northern Scandinavia, where they had a significant local atmospheric warming effect. We find that, during this transport event, the average modeled top of atmosphere (TOA shortwave direct and semi-direct radiative effect (DSRE north of 60° N over snow and ice-covered surfaces reaches +0.58 W m−2, peaking at +3.3 W m−2 at noon over Scandinavia and Finland.

  15. Changes of Bulgarian Coastal Dune Landscape under Anthropogenic Impact

    Science.gov (United States)

    Palazov, A.; Young, R.; Stancheva, M.; Stanchev, H.

    2012-04-01

    At one time large sand dune formations were widely distributed along the Bulgarian coast. However, due to increased urbanization in the coastal zone, the areas of total dune landscape has been constantly reduced. Dunes presently comprise only 10% of the entire 412 km long coastline of Bulgaria: they embrace a total length of 38.57 km and a total area of 8.78 km2 Important tasks in dune protection are identification of landscape changes for a certain period of time and accurate delineation of sand dune areas. The present research traces sand dune changes along the Bulgarian Black Sea coast over a 27 year period (1983-2010). This period includes also the time of expanded tourist boom and overbuilding of the coastal zone, and respectively presents the largest dune changes and reductions. Based on the landscape change analyst in GIS environment the study also aims to explore the importance of different natural and human factors in driving the observed dune alterations and destruction. To detect and assess dune changes during the last 3 decades, we used data for sand dunes derived from several sources at different time periods in order to compare changes in shoreline positions, dune contours and areas: i) Topographic maps in 1:5,000 scale from 1983; ii) Modern Very High Resolution orthophotographs from 2006 and 2010; iii) QuickBird Very High Resolution satellite images from 2009; iv) Statistical information for population and tourist infrastructure is also used to consider the influence of human pressure and hotel developments on the dune dynamics. In addition, for more detailed description and visualization of main dune types, digital photos have been taken at many parts of the Bulgarian coast. The study was performed in GIS environment. Based on the results obtained the dunes along the Bulgarian coast were divided into three main groups with relation to the general factors responsible for their alterations: i) Dunes that have decreased in result of shoreline retreat

  16. The role of anthropogenic and natural factors in shaping the geochemical evolution of groundwater in the Subei Lake basin, Ordos energy base, Northwestern China.

    Science.gov (United States)

    Liu, Fei; Song, Xianfang; Yang, Lihu; Han, Dongmei; Zhang, Yinghua; Ma, Ying; Bu, Hongmei

    2015-12-15

    Groundwater resources are increasingly exploited for industrial and agricultural purposes in many arid regions globally, it is urgent to gain the impact of the enhanced anthropogenic pressure on the groundwater chemistry. The aim of this study was to acquire a comprehensive understanding of the evolution of groundwater chemistry and to identify the impact of natural and anthropogenic factors on the groundwater chemistry in the Subei Lake basin, Northwestern China. A total of 153 groundwater samples were collected and major ions were measured during the three campaigns (August and December 2013, May 2014). At present, the major hydrochemical facies in unconfined groundwater are Ca-Mg-HCO3, Ca-Na-HCO3, Na-Ca-HCO3, Na-HCO3, Ca-Mg-SO4 and Na-SO4-Cl types, while the main hydrochemical facies in confined groundwater are Ca-Mg-HCO3, Ca-Na-HCO3, Na-Ca-HCO3, Ca-HCO3 and Na-HCO3 types. Relatively greater seasonal variation can be observed in the chemical constituents of confined groundwater than that of unconfined groundwater. Rock weathering predominates the evolution of groundwater chemistry in conjunction with the cation exchange, and the dissolution/precipitation of gypsum, halite, feldspar, calcite and dolomite are responsible for the chemical constituents of groundwater. Anthropogenic activities can be classified as: (1) groundwater overexploitation; (2) excessive application of fertilizers in agricultural areas. Due to intensive groundwater pumping, the accelerated groundwater mineralization resulted in the local changes in hydrochemical facies of unconfined groundwater, while the strong mixture, especially a large influx of downward leakage from the unconfined aquifer into the confined aquifer, played a vital role in the fundamental variation of hydrochemical facies in confined aquifer. The nitrate contamination is mainly controlled by the local hydrogeological settings coupled with the traditional flood irrigation. The deeper insight into geochemical evolution of

  17. Vegetation and soil dynamics under climatic to anthropogenic forcing through the Holocene in Eastern France

    Science.gov (United States)

    Doyen, Elise; Vannière, Boris; Gauthier, Emilie; Bichet, Vincent; Berger, Jean-François; Arnaud, Fabien

    2010-05-01

    Small lakes with little catchment areas, and high resolution Holocene sediment infilling, offer the interest to record mainly local perturbation and to study the switch from climatic to anthropogenic forcing. Two cores were extracted from Lake Antre in the Jura Mountains (Eastern France, 798 m a.s.l) and Lake Moras located on a low-elevated plateau from the upper Rhone valley (Eastern France, 304 m a.s.l). Cores taken from the deep zone of the lakes present continuous sedimentary series from the Late-glacial (15 000 cal. BP) for Lake Moras and from the Atlantic chronozone (6000 cal. BP) for Lake Antre. Several archaeological excavations and investigations around Lakes Antre and Moras give evidence of major human occupation during Gallo-roman period, while former settlements are indicating by Pre- and Protohistoric archaeological artifacts. Multi-proxy reconstructions with high temporal resolution were undertaken: vegetation dynamics by pollen analysis, fire history by the quantification of microscopic charcoal and soil erosion by magnetic susceptibility measurements. Before the anthropogenic forcing, during the mid-Holocene environment of both lakes are constituted mainly by a dense mixed oak forest. The first palaeoecological signs of anthropogenic impact on the two sites appear to have been discontinuous and limited. They appear at the early Neolithic (ca 6000 cal .BP) for Lake Moras and during the Bronze Age (4000 to 3000 cal .BP) for Lake Antre. For the both sites, all the proxies indicate an acceleration of human impact around 3000 to 2700 cal. BP i.e. at the transition between the Bronze Age and the beginning of the Iron Age. The dense forest and the Alnus dominated vegetation on borders of lakes are affected by several clearances. The influx of micro-charcoal increases due to the use of the fire for clearing and manage settlements. The development of Poaceae and Anthropogenic Pollen Indicators (API) suggest an expansion of pastures, whereas the farming

  18. Accounting for anthropogenic actions in modeling of stream flow at the regional scale

    Science.gov (United States)

    David, C. H.; Famiglietti, J. S.

    2013-12-01

    The modeling of the horizontal movement of water from land to coasts at scales ranging from 10^5 km^2 to 10^6 km^2 has benefited from extensive research within the past two decades. In parallel, community technology for gathering/sharing surface water observations and datasets for describing the geography of terrestrial water bodies have recently had groundbreaking advancements. Yet, the fields of computational hydrology and hydroinformatics have barely started to work hand-in-hand, and much research remains to be performed before we can better understand the anthropogenic impact on surface water through combined observations and models. Here, we build on our existing river modeling approach that leverages community state-of-the-art tools such as atmospheric data from the second phase of the North American Land Data Assimilation System (NLDAS2), river networks from the enhanced National Hydrography Dataset (NHDPlus), and observations from the U.S. Geological Survey National Water Information System (NWIS) obtained through CUAHSI webservices. Modifications are made to our integrated observational/modeling system to include treatment for anthropogenic actions such as dams, pumping and divergences in river networks. Initial results of a study focusing on the entire State of California suggest that availability of data describing human alterations on natural river networks associated with proper representation of such actions in our models could help advance hydrology further. Snapshot from an animation of flow in California river networks. The full animation is available at: http://www.ucchm.org/david/rapid.htm.

  19. Anthropogenic mortality on coral reefs in Caribbean Panama predates coral disease and bleaching.

    Science.gov (United States)

    Cramer, Katie L; Jackson, Jeremy B C; Angioletti, Christopher V; Leonard-Pingel, Jill; Guilderson, Thomas P

    2012-06-01

    Caribbean reef corals have declined precipitously since the 1980s due to regional episodes of bleaching, disease and algal overgrowth, but the extent of earlier degradation due to localised historical disturbances such as land clearing and overfishing remains unresolved. We analysed coral and molluscan fossil assemblages from reefs near Bocas del Toro, Panama to construct a timeline of ecological change from the 19th century-present. We report large changes before 1960 in coastal lagoons coincident with extensive deforestation, and after 1960 on offshore reefs. Striking changes include the demise of previously dominant staghorn coral Acropora cervicornis and oyster Dendrostrea frons that lives attached to gorgonians and staghorn corals. Reductions in bivalve size and simplification of gastropod trophic structure further implicate increasing environmental stress on reefs. Our paleoecological data strongly support the hypothesis, from extensive qualitative data, that Caribbean reef degradation predates coral bleaching and disease outbreaks linked to anthropogenic climate change. PMID:22462739

  20. Climate responses to anthropogenic emissions of short-lived climate pollutants

    Science.gov (United States)

    Baker, L. H.; Collins, W. J.; Olivié, D. J. L.; Cherian, R.; Hodnebrog, Ø.; Myhre, G.; Quaas, J.

    2015-07-01

    Policies to control air quality focus on mitigating emissions of aerosols and their precursors, and other short-lived climate pollutants (SLCPs). On a local scale, these policies will have beneficial impacts on health and crop yields, by reducing particulate matter (PM) and surface ozone concentrations; however, the climate impacts of reducing emissions of SLCPs are less straightforward to predict. In this paper we consider a set of idealized, extreme mitigation strategies, in which the total anthropogenic emissions of individual SLCP emissions species are removed. This provides an upper bound on the potential climate impacts of such air quality strategies. We focus on evaluating the climate responses to changes in anthropogenic emissions of aerosol precursor species: black carbon (BC), organic carbon (OC) and sulphur dioxide (SO2). We perform climate integrations with four fully coupled atmosphere-ocean global climate models (AOGCMs), and examine the effects on global and regional climate of removing the total land-based anthropogenic emissions of each of the three aerosol precursor species. We find that the SO2 emissions reductions lead to the strongest response, with all models showing an increase in surface temperature focussed in the Northern Hemisphere mid and (especially) high latitudes, and showing a corresponding increase in global mean precipitation. Changes in precipitation patterns are driven mostly by a northward shift in the ITCZ (Intertropical Convergence Zone), consistent with the hemispherically asymmetric warming pattern driven by the emissions changes. The BC and OC emissions reductions give a much weaker response, and there is some disagreement between models in the sign of the climate responses to these perturbations. These differences between models are due largely to natural variability in sea-ice extent, circulation patterns and cloud changes. This large natural variability component to the signal when the ocean circulation and sea-ice are

  1. Hunting, Exotic Carnivores, and Habitat Loss: Anthropogenic Effects on a Native Carnivore Community, Madagascar.

    Directory of Open Access Journals (Sweden)

    Zach J Farris

    Full Text Available The wide-ranging, cumulative, negative effects of anthropogenic disturbance, including habitat degradation, exotic species, and hunting, on native wildlife has been well documented across a range of habitats worldwide with carnivores potentially being the most vulnerable due to their more extinction prone characteristics. Investigating the effects of anthropogenic pressures on sympatric carnivores is needed to improve our ability to develop targeted, effective management plans for carnivore conservation worldwide. Utilizing photographic, line-transect, and habitat sampling, as well as landscape analyses and village-based bushmeat hunting surveys, we provide the first investigation of how multiple forms of habitat degradation (fragmentation, exotic carnivores, human encroachment, and hunting affect carnivore occupancy across Madagascar's largest protected area: the Masoala-Makira landscape. We found that as degradation increased, native carnivore occupancy and encounter rates decreased while exotic carnivore occupancy and encounter rates increased. Feral cats (Felis species and domestic dogs (Canis familiaris had higher occupancy than half of the native carnivore species across Madagascar's largest protected landscape. Bird and small mammal encounter rates were negatively associated with exotic carnivore occupancy, but positively associated with the occupancy of four native carnivore species. Spotted fanaloka (Fossa fossana occupancy was constrained by the presence of exotic feral cats and exotic small Indian civet (Viverricula indica. Hunting was intense across the four study sites where hunting was studied, with the highest rates for the small Indian civet (mean=90 individuals consumed/year, the ring-tailed vontsira (Galidia elegans (mean=58 consumed/year, and the fosa (Cryptoprocta ferox (mean=31 consumed/year. Our modeling results suggest hunters target intact forest where carnivore occupancy, abundance, and species richness, are highest

  2. The contribution of anthropogenic bromine emissions to past stratospheric ozone trends: a modelling study

    Directory of Open Access Journals (Sweden)

    B.-M. Sinnhuber

    2009-04-01

    Full Text Available Bromine compounds play an important role in the depletion of stratospheric ozone. We have calculated the changes in stratospheric ozone in response to changes in the halogen loading over the past decades, using a two-dimensional (latitude/height model constrained by source gas mixing ratios at the surface. Model calculations of the decrease of total column ozone since 1980 agree reasonably well with observed ozone trends, in particular when the contribution from very short-lived bromine compounds is included. Model calculations with bromine source gas mixing ratios fixed at 1959 levels, corresponding approximately to a situation with no anthropogenic bromine emissions, show an ozone column reduction between 1980 and 2005 at Northern Hemisphere mid-latitudes of only ≈55% compared to a model run including all halogen source gases. In this sense anthropogenic bromine emissions are responsible for ≈45% of the model estimated column ozone loss at Northern Hemisphere mid-latitudes. However, since a large fraction of the bromine induced ozone loss is due to the combined BrO/ClO catalytic cycle, the effect of bromine would have been smaller in the absence of anthropogenic chlorine emissions. The chemical efficiency of bromine relative to chlorine for global total ozone depletion from our model calculations, expressed by the so called α-factor, is 64 on an annual average. This value is much higher than previously published results. Updates in reaction rate constants can explain only part of the differences in α. The inclusion of bromine from very short-lived source gases has only a minor effect on the global mean α-factor.

  3. The Influence of Pyrogenic, Biogenic and Anthropogenic Emissions on Ozone Production Downwind from Boreal Forest Fires

    Science.gov (United States)

    Finch, Douglas; Palmer, Paul

    2016-04-01

    Boreal forest fires emit pollutants that can have a strong influence on downwind surface ozone concentrations, with potential implications for exceeding air quality regulations. The influence of the mixing of pyrogenic, biogenic and anthropogenic emissions on ozone is not well understood. Using the nested 0.5° latitude x 0.667° longitude GEOS-Chem chemical transport model we track biomass burning plumes in North America. We identify the changes in key chemical reactions within these plumes as well as the sensitivity of ozone to the different emission sources. We illustrate the importance of this method using a case study of a multi-day forest fire during the BORTAS aircraft campaign over eastern Canada during summer 2011. We focus on emissions from the fire on the 17th of July and follow the plume for eight days. After the initial 24 hours of pyrogenic emissions the main source of VOCs is biogenic with increasing emissions from anthropogenic sources including outflow from Quebec City and Newfoundland. Using a Lagrangian framework, we show that the ozone production efficiency (OPE) of this plume decreases steadily as it moves away from the fire but increases rapidly as the plume reaches the east coast of Canada. Using a Eulerian framework we show that ozone mixing ratios of a east coast receptor region increase by approximately 15% even though the ozone tendency of the regional air mass is negative, which we find is due to the arrival of ozone precursors in the plume. We also consider the contribution of anthropogenic outflow over Nova Scotia that originates from the eastern seaboard of the United States to the local chemistry. Using these sensitivity model runs we generate a chemical reaction narrative for the plume trajectory that helps to understand the attribution of observed ozone variations.

  4. Impact of anthropogenic aerosols on summer precipitation in the Beijing-Tianjin-Hebei urban agglomeration in China: Regional climate modeling using WRF-Chem

    Science.gov (United States)

    Wang, Jun; Feng, Jinming; Wu, Qizhong; Yan, Zhongwei

    2016-06-01

    The WRF model with chemistry (WRF-Chem) was employed to simulate the impacts of anthropogenic aerosols on summer precipitation over the Beijing-Tianjin-Hebei urban agglomeration in China. With the aid of a high-resolution gridded inventory of anthropogenic emissions of trace gases and aerosols, we conducted relatively long-term regional simulations, considering direct, semi-direct and indirect effects of the aerosols. Comparing the results of sensitivity experiments with and without emissions, it was found that anthropogenic aerosols tended to enhance summer precipitation over the metropolitan areas. Domain-averaged rainfall was increased throughout the day, except for the time around noon. Aerosols shifted the precipitation probability distribution from light or moderate to extreme rain. Further analysis showed that the anthropogenic aerosol radiative forcing had a cooling effect at the land surface, but a warming effect in the atmosphere. However, enhanced convective strength and updrafts accompanied by water vapor increases and cyclone-like wind shear anomalies were found in the urban areas. These responses may originate from cloud microphysical effects of aerosols on convection, which were identified as the primary cause for the summer rainfall enhancement.

  5. "Gas and fat embolic syndrome" involving a mass stranding of beaked whales (family Ziphiidae) exposed to anthropogenic sonar signals.

    Science.gov (United States)

    Fernández, A; Edwards, J F; Rodríguez, F; Espinosa de los Monteros, A; Herráez, P; Castro, P; Jaber, J R; Martín, V; Arbelo, M

    2005-07-01

    A study of the lesions of beaked whales (BWs) in a recent mass stranding in the Canary Islands following naval exercises provides a possible explanation of the relationship between anthropogenic, acoustic (sonar) activities and the stranding and death of marine mammals. Fourteen BWs were stranded in the Canary Islands close to the site of an international naval exercise (Neo-Tapon 2002) held on 24 September 2002. Strandings began about 4 hours after the onset of midfrequency sonar activity. Eight Cuvier's BWs (Ziphius cavirostris), one Blainville's BW (Mesoplodon densirostris), and one Gervais' BW (Mesoplodon europaeus) were examined postmortem and studied histopathologically. No inflammatory or neoplastic processes were noted, and no pathogens were identified. Macroscopically, whales had severe, diffuse congestion and hemorrhage, especially around the acoustic jaw fat, ears, brain, and kidneys. Gas bubble-associated lesions and fat embolism were observed in the vessels and parenchyma of vital organs. In vivo bubble formation associated with sonar exposure that may have been exacerbated by modified diving behavior caused nitrogen supersaturation above a threshold value normally tolerated by the tissues (as occurs in decompression sickness). Alternatively, the effect that sonar has on tissues that have been supersaturated with nitrogen gas could be such that it lowers the threshold for the expansion of in vivo bubble precursors (gas nuclei). Exclusively or in combination, these mechanisms may enhance and maintain bubble growth or initiate embolism. Severely injured whales died or became stranded and died due to cardiovascular collapse during beaching. The present study demonstrates a new pathologic entity in cetaceans. The syndrome is apparently induced by exposure to mid-frequency sonar signals and particularly affects deep, long-duration, repetitive-diving species like BWs. PMID:16006604

  6. AMPHIBIAN COMMUNITIES IN BIOGEOCOENOSIS WITH DIFFERENT STAGES OF ANTHROPOGENIC CLYMAX

    Directory of Open Access Journals (Sweden)

    Marchenkovskaya А. А.

    2013-04-01

    Full Text Available We examined the abundance of juvenile (fingerlings and yearlings and sexually mature (3-6 years of various anurans at various biotopes with different degrees of anthropogenic influence. Population analysis has revealed that the number of juveniles in all the habitats are depended on type and level of anthropogenic influence. In all the habitats the most numerous species was synanthropic bufo viridis. In biotopes with high contamination of pollutants, only one species of amphibians - the marsh frog has populations with juveniles migrating here in the early fall. The highest number of mature individuals registered for the population of Bombina bombina, pelobates fuscus and in one biotope for hyla arborea. The populations of pelophylax ridibundus could be considered as the most balanced by number of juvenile and mature individuals.

  7. Microbial DNA records historical delivery of anthropogenic mercury.

    Science.gov (United States)

    Poulain, Alexandre J; Aris-Brosou, Stéphane; Blais, Jules M; Brazeau, Michelle; Keller, Wendel Bill; Paterson, Andrew M

    2015-12-01

    Mercury (Hg) is an anthropogenic pollutant that is toxic to wildlife and humans, but the response of remote ecosystems to globally distributed Hg is elusive. Here, we use DNA extracted from a dated sediment core to infer the response of microbes to historical Hg delivery. We observe a significant association between the mercuric reductase gene (merA) phylogeny and the timing of Hg deposition. Using relaxed molecular clock models, we show a significant increase in the scaled effective population size of the merA gene beginning ~200 years ago, coinciding with the Industrial Revolution and a coincident strong signal for positive selection acting on residues in the terminal region of the mercuric reductase. This rapid evolutionary response of microbes to changes in the delivery of anthropogenic Hg indicates that microbial genomes record ecosystem response to pollutant deposition in remote regions. PMID:26057844

  8. Primary production in systems subject to natural and anthropogenic eutrophication

    OpenAIRE

    Loureiro, Sofia

    2005-01-01

    The input of nutrients to the aquatic system can have both natural (e.g. upwelling events) and human (e.g. sewage discharges, run-off of inorganic fertilizers from agricultural land) origins. The level of anthropogenic (human) eutrophication has grown in the past century. Primary production rates have increased significantly as a response, which can lead to harmful effects when the balance between the production and decomposition of organic matter is affected. These include the depletion of o...

  9. Management of Anthropogenic Factor in Mureş County Forests

    Directory of Open Access Journals (Sweden)

    Covrig Ilie

    2014-05-01

    Full Text Available The analysis and drafting of a conclusion regarding the current state of the anthropogenic influence on the forests were conducted by the study of forest planning and other documents that serve the purpose of the research. By following the paths in the forests of Mureş county, several remarks were noted on the state of private and state-owned forest areas: the forester’s intervention in the woods, in terms of the application of silvicultural treatments and forest regeneration and promotion of the basic natural type of forest, the mapping of anthropogenically damaged areas, remarks on the planning of guarding activities and preventing illegal actions in the woods. The actions that cause damage to the forest and the general stock of wood are identified especially in terms of illegal felling. The damages caused though illegal felling during the analyzed period (1970 - 2013, enable us to assert that this kind of damages were recorded throughout the entire analyzed interval. The causes determining a high anthropogenic pressure on the forests are easily identified by the legislative gaps, social poverty of the Romanian society, the influence of the political factor on the national forest strategy, impairment of the forester’s authority in the forests, the dependence of local communities to the forests etc. All these require identification of immediate solutions for the recovery of the anthropogenically damaged areas by afforestation, provision of a sole, coherent and efficient legislative framework, approach of a new concept in terms of supervision and control in the forests.

  10. Chapter 5: Anthropogenic methane sources, emissions and future projections

    OpenAIRE

    HOGLUND-ISAKSSON Lena; Thomson, Allison; Kupiainen, Kaarle; Rao, Shilpa; Janssens-Maenhout, Greet

    2015-01-01

    This chapter reviews recent global assessments of anthropogenic methane emissions, their expected future development and estimated reduction potentials. Because methane is a gas which mixes rapidly in the global atmosphere, it is of interest to review emissions at the global scale as well as for the area covered by the eight Arctic nations. The following key findings have been identified: • Bottom-up emission inventories agree fairly well in terms of the overall magnitude of global anthropogeni...

  11. ANTHROPOGENIC PRESSURE ON FORESTS IN THE GLOBAL ERA

    OpenAIRE

    Petrica Sorin ANGHELU?A; Arghir Vasile CIOBOTARU

    2014-01-01

    Of all terrestrial ecosystems, the forest is the most important and complex ecosystem. Because of humans the largest forests of the world are in serious danger. Anthropogenic pressure on the forest is becoming greater with increasing global population. Characteristic new management methods must be found, among others, naturally regenerating forests, ecological technologies in forestry, achieving various structures as close to that of natural forests. The measures presented are able to contrib...

  12. CO2 Biogenic vs Anthropogenic Sectoral Contribution for INFLUX

    Science.gov (United States)

    Lopez-Coto, I.; Prasad, K.; Hu, H.; Whetstone, J. R.; Miles, N. L.; Richardson, S.; Lauvaux, T.; Davis, K. J.; Turnbull, J. C.; Karion, A.; Sweeney, C.; Brewer, A.; Hardesty, M.; Cambaliza, M. O. L.; Shepson, P. B.; Patarasuk, R.; Gurney, K. R.

    2014-12-01

    The Indianapolis Flux Experiment (INFLUX) aims to use a top-down inversion methodology to quantify sources of Greenhouse Gas (GHG) emissions over an urban domain with high spatial and temporal resolution. This project is an experimental test bed which is intended to establish reliable methods for quantifying and validating GHG emissions independently of the inventory methods typically used for Measurement, Reporting and Verification (MRV) of pollution sources. Analyzing the contribution of different source types or sectors is a fundamental step in order to achieve an accuracy level desired for such MRV applications. This is especially challenging when attempting to determine anthropogenic emissions during the growing season since biological GHG fluxes reach a maximum at this time. To this end, the Weather Research and Forecasting Model (WRF-ARW) version 3.5.1 was used along with a modified version of the Green House Gases chemistry module for simulating the CO2 mole fraction transport during September and October 2013. Sectoral anthropogenic CO2 emissions were obtained from Hestia 2012 and from Vulcan 2002 beyond the spatial coverage of Hestia. Biogenic CO2 emissions were simulated by using an augmented version of the "Vegetation Photosynthesis and Respiration Model" (VPRM) included in WRF-CHEM. An implementation of the unconstrained nonlinear global optimization method of Nelder and Mead was employed to find the optimum values for the VPRM parameters for each vegetation category by using data from Ameriflux eddy covariance flux towers. Here we present a preliminary assessment of the relative contribution of biological vs sectoral anthropogenic CO2 fluxes on the INFLUX measurements network. The simulations are compared to tower and aircraft measurements that include trace gases with the capacity to distinguish observationally anthropogenic and biogenic CO2 sources and sinks. In addition, an evaluation of the sensitivity of the sectoral attribution to meteorological

  13. Natural aerosol–climate feedbacks suppressed by anthropogenic aerosol

    OpenAIRE

    Spracklen, DV; A. Rap

    2013-01-01

    The natural environment is an important source of atmospheric aerosol such as dust, sea spray, and wildfire smoke. Climate controls many of these natural aerosol sources, which, in turn, can alter climate through changing the properties of clouds and the Earth's radiative balance. However, the Earth's atmosphere is now heavily modified by anthropogenic pollution aerosol, but how this pollution may alter these natural aerosol–climate feedbacks has not been previously explored. Here we use a gl...

  14. Polynomial cointegration tests of anthropogenic impact on global warming

    OpenAIRE

    Beenstock, M; Y. Reingewertz; N. Paldor

    2012-01-01

    We use statistical methods for nonstationary time series to test the anthropogenic interpretation of global warming (AGW), according to which an increase in atmospheric greenhouse gas concentrations raised global temperature in the 20th century. Specifically, the methodology of polynomial cointegration is used to test AGW since during the observation period (1880–2007) global temperature and solar irradiance are stationary in 1st differences whereas greenhouse gases and aerosol forcing...

  15. Poorest countries experience earlier anthropogenic emergence of daily temperature extremes

    OpenAIRE

    Harrington, Luke; D. Frame; Fischer, Erich; Hawkins, Ed; Joshi, Manoj; Jones, Chris

    2016-01-01

    Understanding how the emergence of the anthropogenic warming signal from the noise of internal variability translates to changes in extreme event occurrence is of crucial societal importance. By utilising simulations of cumulative carbon dioxide (CO2) emissions and temperature changes from eleven earth system models, we demonstrate that the inherently lower internal variability found at tropical latitudes results in large increases in the frequency of extreme daily temperatures (exceedances o...

  16. Stable nitrogen isotopes in coastal macroalgae: Geographic and anthropogenic variability

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Inés G., E-mail: ines.gonzalez@co.ieo.es; Bode, Antonio

    2013-01-15

    Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ{sup 15}N). In this study δ{sup 15}N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ{sup 15}N was not related to either inorganic nitrogen concentrations or δ{sup 15}N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ{sup 15}N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ{sup 15}N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15 × 10{sup 3} inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ{sup 15}N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. - Highlights: ► Anthropogenic versus upwelling nitrogen effect on macroalgal δ{sup 15}N was studied. ► The influence of populations and upwelling has not been made before on macroalgal δ{sup 15}N. ► Natural variability has not been taken into account in most biomonitoring studies. ► Upwelling explains most of the variability in δ{sup 15}N in macroalgae.

  17. Laboratory experiments on dynamics of anthropogenic ferrimagnetics in sand formations

    Czech Academy of Sciences Publication Activity Database

    Kapička, Aleš; Fialová, Hana; Petrovský, Eduard; Kodešová, R.; Kopáč, J.

    2008-01-01

    Roč. 38, Special issue (2008), s. 52-53. ISSN 1335-2806. [Paleo, Rock and Environmental Magnetism. Castle Meeting /11./. 22.06.2008-28.06.2008, Bojnice] R&D Projects: GA AV ČR IAA300120701 Institutional research plan: CEZ:AV0Z30120515 Keywords : soil pollution * dynamics of anthropogenic particles * magnetic susceptibility Subject RIV: DE - Earth Magnetism, Geodesy, Geography

  18. Polynomial cointegration tests of anthropogenic impact on global warming

    OpenAIRE

    M. Beenstock; Y. Reingewertz; N. Paldor

    2012-01-01

    We use statistical methods for nonstationary time series to test the anthropogenic interpretation of global warming (AGW), according to which an increase in atmospheric greenhouse gas concentrations raised global temperature in the 20th century. Specifically, the methodology of polynomial cointegration is used to test AGW since during the observation period (1880–2007) global temperature and solar irradiance are stationary in 1st differences, whereas greenhouse gas and aerosol forcings are st...

  19. Stable nitrogen isotopes in coastal macroalgae: geographic and anthropogenic variability.

    Science.gov (United States)

    Viana, Inés G; Bode, Antonio

    2013-01-15

    Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ(15)N). In this study δ(15)N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ(15)N was not related to either inorganic nitrogen concentrations or δ(15)N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ(15)N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ(15)N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15×10(3) inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ(15)N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. PMID:23247291

  20. Distinguishing natural hydrocarbons from anthropogenic contamination in ground water

    International Nuclear Information System (INIS)

    Differentiation between natural and anthropogenic sources of ground-water contamination by petroleum hydrocarbons is necessary in areas where natural hydrocarbons may be present in the subsurface. Because of the similarity in composition between natural and refined petroleum, the use of statistical techniques to discern trends is required. In this study, both multivariate plotting techniques and principal component analysis were used to investigate the origin of hydrocarbons from a variety of study sites. Ground-water and gas samples were collected from the Niagara Falls area and from three gasoline stations where leaking underground storage tanks had been found. Although soil gas surveys are used to indicate the presence of hydrocarbons, they were not useful in differentiating between natural and anthropogenic sources of contamination in ground water. Propane and pentene were found to be the most useful chemical parameters in discriminating between the natural and anthropogenic sources. These chemicals are not usually measured in investigations of ground-water contamination, yet analysis can be conducted by most environmental laboratories using conventional methods

  1. The relationship between anthropogenic dust and population over global semi-arid regions

    Science.gov (United States)

    Guan, Xiaodan; Huang, Jianping; Zhang, Yanting; Xie, Yongkun; Liu, Jingjing

    2016-04-01

    Although anthropogenic dust has received more attention from the climate research community, its dominant role in the production process is still not identified. In this study, we analysed the relationship between anthropogenic dust and population density/change over global semi-arid regions and found that semi-arid regions are major source regions in producing anthropogenic dust. The results showed that the relationship between anthropogenic dust and population is more obvious in cropland than in other land cover types (crop mosaics, grassland, and urbanized regions) and that the production of anthropogenic dust increases as the population density grows to more than 90 persons km-2. Four selected semi-arid regions, namely East China, India, North America, and North Africa, were used to explore the relationship between anthropogenic dust production and regional population. The most significant relationship between anthropogenic dust and population occurred in an Indian semi-arid region that had a greater portion of cropland, and the high peak of anthropogenic dust probability appeared with 220 persons km-2 of population density and 60 persons km-2 of population change. These results suggest that the influence of population on production of anthropogenic dust in semi-arid regions is obvious in cropland regions. However, the impact does not always have a positive contribution to the production of anthropogenic dust, and overly excessive population will suppress the increase of anthropogenic dust. Moreover, radiative and climate effects of increasing anthropogenic dust need more investigation.

  2. Contribution of natural and anthropogenic aerosols to optical properties and radiative effects over an urban location

    International Nuclear Information System (INIS)

    A method to determine the contribution of natural and anthropogenic aerosol species to aerosol radiative forcing using surface-based, columnar and vertical profile measurements, optical properties and radiative transfer models is outlined. Aerosol optical properties and radiative fluxes measured during 2008 over Ahmedabad, an urban city located in western India are utilized. Mid-visible aerosol optical depth (AOD) does not show a strong seasonal variation, while α, the Ångström exponent, exhibits significant seasonal variation. α is higher during winter and post-monsoon, when fine mode aerosols are dominant, while α is lower during pre-monsoon and monsoon, when coarse mode aerosols are abundant. The contribution of mineral dust to the total aerosol mass is higher than 55% as the study location is in a semi-arid region. Natural aerosols (mineral dust and sea salt) dominate the aerosol mass concentration, while anthropogenic aerosols (water soluble aerosols and black carbon) dominate the aerosol optical depth. The percentage contribution of black carbon to the net atmospheric forcing is larger than 65% throughout the year, corroborating that black carbon aerosol is a strong contributor to global warming on regional scales. Black carbon aerosols contribute 50% or more to the aerosol radiative forcing at the surface, thus, significantly contributing to solar dimming. The large atmospheric warming and the surface forcing due to black carbon aerosols can influence the hydrological cycle. Results emphasize that aerosol radiative forcing is governed more by aerosol optical properties (aerosol optical depth and single scattering albedo) rather than their mass, and there exists no linear relation between mass, optical depth and radiative effects of different aerosol species. These results and the relationship can be used to delineate the anthropogenic influence of aerosols from their natural counterpart, because anthropogenic aerosols in the fine mode (lower mass) give

  3. Precipitation over two Southern Hemisphere locations: Long-term variation linked to natural and anthropogenic forcings

    Science.gov (United States)

    Heredia, Teresita; Elias, Ana G.

    2016-03-01

    The precipitation over Tucuman (26.8°S, 65.2°W), Argentina, and Sidney (33.8°S, 151.2°E), Australia, present similar long-term variation patterns. In this work anthropogenic and solar forcings are analyzed as possible drivers of this behavior. Due to the nature of the processes that lead to precipitation, the discernment between solar and anthropogenic effects, and the link between precipitation and solar activity are highly complex and hard to detect. The aim of this work is to convey the importance of recognizing and quantifying the different forcing acting on precipitation which sometimes are not exposed by a statistical analysis. Annual mean precipitation time series together with solar and geomagnetic activity indices and atmospheric CO2 are analyzed. In order to survey the role of different forcing on precipitation variation we used wavelet and regression analysis with CO2, Rz and aa as independent variables acting as anthropogenic, solar and geomagnetic activity forcing respectively. In the long-term, all of them, considered separately, would induce a similar mean increase in precipitation. The increasing concentration of greenhouse gases, which is thought to be the main factor causing the global warming, is expected to induce an increasing trend of ∼0.8 mm/year, according to some authors. In our case, we obtain a much smaller value: ∼0.15 mm/year which in addition, is similar to the expected forcing from Rz or aa. The wavelet analysis yield significant results for the quasi-decadal and longer-term variations only in the case of Sydney. Significant correlations at time-scales longer than 22 years are also obtained through the regression analysis for Sydney. Although Tucuman do not present significant results, there is a clear similar behavior in the long-term trend. In spite of the fact that the present analysis do not allow us to determine the "true" forcing of the overall increasing trend observed in precipitation, it points out not only

  4. The influence of natural and anthropogenic secondary sources on the glyoxal global distribution

    Directory of Open Access Journals (Sweden)

    S. Myriokefalitakis

    2008-08-01

    Full Text Available Glyoxal, the smallest dicarbonyl, which has recently been observed from space, is expected to provide indications on volatile organic compounds (VOC oxidation and secondary aerosol formation in the troposphere. Glyoxal (CHOCHO is known to be mostly of natural origin and is produced during biogenic VOC oxidation. However, a number of anthropogenically emitted hydrocarbons, like acetylene and aromatics, have been positively identified as CHOCHO precursors. The present study investigates the contribution of pollution to the CHOCHO levels by taking into account the secondary chemical formation of CHOCHO from precursors emitted from biogenic, anthropogenic and biomass burning sources. The impact of potential primary land emissions of CHOCHO is also investigated. A global 3-dimensional chemistry transport model of the troposphere (TM4-ECPL able to simulate the gas phase chemistry coupled with all major aerosol components is used.

    The secondary anthropogenic contribution from fossil fuel and industrial VOCs emissions oxidation to the CHOCHO columns is found to reach 20–70% in the industrialized areas of the Northern Hemisphere and 3–20% in the tropics. This secondary CHOCHO source is on average three times larger than that from oxidation of VOCs from biomass burning sources. The chemical production of CHOCHO is calculated to equal to about 56 Tg y−1 with 70% being produced from biogenic hydrocarbons oxidation, 17% from acetylene, 11% from aromatic chemistry and 2% from ethene and propene. CHOCHO is destroyed in the troposphere primarily by reaction with OH radicals (23% and by photolysis (63%, but it is also removed from the atmosphere through wet (8% and dry deposition (6%. Potential formation of secondary organic aerosol through CHOCHO losses on/in aerosols and clouds is neglected here due to the significant uncertainties associated with the underlying chemistry. The global annual mean CHOCHO burden and lifetime in the model

  5. Detection of anthropogenic influence on the evolution of record-breaking temperatures over Europe

    Science.gov (United States)

    Bador, Margot; Terray, Laurent; Boé, Julien

    2016-05-01

    Changes in temperature extreme events are expected as a result of anthropogenic climate change, but uncertainties exist in when and how these changes will be manifest regionally. This is especially the case over Europe due to different methodologies and definitions of temperature extreme events. An alternative approach is to examine changes in record-breaking temperatures. Datasets of observed temperature combined with ensembles of climate model simulations are used to assess the possible causes and significance of record-breaking temperature changes over the late twentieth and twenty-first centuries. A simple detection methodology is first applied to evaluate the extent to which the effect of anthropogenic forcing can be detected in present-day observed and simulated changes in record-breaking temperature. We then study the projected evolution of record-breaking daily minimum and maximum temperatures over the twenty-first century in Europe with a climate model. The same detection approach is used to identify the time of emergence of the anthropogenic signal relative to a model-derived estimate of internal variability. From the 1980s onwards, a change in the evolution of cold and warm records is observed and simulated, but it still remains in the range of internal variability until the end of the twentieth century. Minimum and maximum record-breaking temperatures tend to occur (respectively) less and more often than during the 1960s and 1970s taken as representative of a stationary climate. Model simulations with natural forcing only fail to reproduce the observed changes after the 1980s while the latter are compatible with simulations constrained by anthropogenic forcings. The deviation from the characteristic behavior of a stationary climate record-wise initiated in the 1980s is projected to accentuate during the twenty-first century. Annual changes become inconsistent with the model-derived internal variability between the 2020s and 2030s. Over the last three

  6. Natural and anthropogenic rare earth elements in Lago de Paranoá, Brasilia, Brazil

    Science.gov (United States)

    Merschel, Gila; Baldewein, Linda; Bau, Michael; Dantas, Elton Luiz; Walde, Detlef; Bühn, Bernhard

    2014-05-01

    Rare earth elements (REE) belong to the group of particle reactive elements and occur at ultratrace levels in natural waters. They are exclusively trivalent, but Ce and Eu can also be tetravalent and divalent, respectively, depending on the redox-level, the pH and the temperature of the fluid. Due to these redox changes, normalized REE patterns may show Ce and/or Eu anomalies. Recently, these high-tech metals raised significant public attention, as they are of great economic importance and consumption and hence release into the environment increased sharply. The most prominent example of a REE contamination is anthropogenic Gd, which is derived from Gd-based contrast agents used in magnetic resonance imaging. Due to their high stabilities, these compounds are not readily removed by commonly applied waste water treatment technologies and, therefore, are released from treatment plants into surface and ground waters. Hence, this anthropogenic Gd can be used as a tracer for the presence of waste water-derived substances such as pharmaceuticals and personal care products in river, lake, ground and tap waters. Lago de Paranoá is an artificial reservoir lake in the city of Brasilia, Brazil, and is currently considered a potential freshwater resource. The city's two waste water treatment plants are located on its shore and their effluents are discharged into the lake. To investigate the level of contamination, we took water samples at 11 stations in the lake and compared the REE concentrations in unfiltered and filtered (<200 nm) lake water. The unfiltered water samples show light REE enrichment (LaSN/YbSN: 1.37-1.98) and high REE concentrations (Sum REE: 192 - 476 ng/L), while the unfiltered water samples are heavy REE enriched (LaSN/YbSN: 0.15-0.61) at lower concentrations (Sum REE: 50 - 85 ng/L). This is due to the fact that light REE are preferentially bound to particle surfaces, while the heavy REE are preferentially complexed with ligands in solution. In marked

  7. Monthly-averaged anthropogenic aerosol direct radiative forcing over the Mediterranean from AERONET derived aerosol properties

    Directory of Open Access Journals (Sweden)

    A. Bergamo

    2008-07-01

    Full Text Available The all-sky direct radiative effect by anthropogenic aerosol (DREa is calculated in the solar (0.3–4 μm and infrared (4–200 μm spectral ranges for six Mediterranean sites. The sites are differently affected by pollution and together reflect typical aerosol impacts that are expected over land sites of the central Mediterranean basin. Central to the simulations are aerosol optical properties from AERONET sun-/sky-photometer statistics for the year 2003. A discussion on the variability of the overall (natural+anthropogenic aerosol properties with site location is provided. Supplementary data include MODIS satellite sensor based solar surface albedos, ISCCP products for high- mid- and low cloud cover and estimates for the anthropogenic aerosol fraction from global modelling. Since anthropogenic aerosol particles are considered to be smaller than 1 μm in size, mainly the solar radiation transfer is affected with impacts only during sun-light hours. At all sites the (daily average solar DREa is negative all year round at the top of the atmosphere (ToA. Hence, anthropogenic particles produce over land sites of the central Mediterranean a significant cooling effect. Monthly DREa values vary from site to site and are seasonal dependent as a consequence of the seasonal dependence of available sun-light and microphysical aerosol properties. At the ToA the monthly average DREa is −(4±1 W m−2 during spring-summer (SS, April–September and −(2±1 W m−2 during autumn-winter (AW, October–March at the polluted sites. In contrast, it varies between −(3±1 W m−2 and −(1±1 W m−2 on SS and AW, respectively at the less polluted site. Due to atmospheric absorption the DREa at the surface is larger than at the ToA. At the surface the monthly average DREa varies between the most and the least polluted site between −(7±1 W m−2 and

  8. Monthly-averaged anthropogenic aerosol direct radiative forcing over the Mediterranean based on AERONET aerosol properties

    Directory of Open Access Journals (Sweden)

    A. Bergamo

    2008-12-01

    Full Text Available The all-sky direct radiative effect by anthropogenic aerosol (DREa is calculated in the solar (0.3–4 μm and infrared (4–200 μm spectral ranges for six Mediterranean sites. The sites are differently affected by pollution and together reflect typical aerosol impacts that are expected over land and coastal sites of the central Mediterranean basin. Central to the simulations are aerosol optical properties from AERONET sun-/sky-photometer statistics for the year 2003. A discussion on the variability of the overall (natural + anthropogenic aerosol properties with site location is provided. Supplementary data include MODIS satellite sensor based solar surface albedos, ISCCP products for high- mid- and low cloud cover and estimates for the anthropogenic aerosol fraction from global aerosol models. Since anthropogenic aerosol particles are considered to be smaller than 1 μm in size, mainly the solar radiation transfer is affected with impacts only during sun-light hours. At all sites the (daily average solar DREa is negative all year round at the top of the atmosphere (ToA. Hence, anthropogenic particles produce over coastal and land sites of the central Mediterranean a significant cooling effect. Monthly DREa values vary from site to site and are seasonally dependent as a consequence of the seasonal dependence of available sun-light and microphysical aerosol properties. At the ToA the monthly average DREa is −(4±1 W m−2 during spring-summer (SS, April–September and −(2±1 W m−2 during autumn-winter (AW, October–March at the polluted sites. In contrast, it varies between −(3±1 W m−2 and −(1±1 W m−2 on SS and AW, respectively at the less polluted site. Due to atmospheric absorption the DREa at the surface is larger than at the ToA. At the surface the monthly average DREa varies between the most and the least polluted

  9. Characterization of anthropogenic sediment particles after a transboundary water pollution of river Tisza using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Osan, Janos E-mail: osan@sunserv.kfki.hu; Toeroek, Szabina; Alfoeldy, Balint; Falkenberg, Gerald

    2004-05-21

    At the beginning of 2000, a major mining accident occurred in the Romanian part of the Tisza catchment area due to tailings dam failure releasing huge amounts of heavy metals to the river. Sediment samples were taken from the main riverbed at six sites in Hungary, on March 16, 2000. The objective of this work was to characterize the anthropogenic particles in river sediment previously selected by single-particle electron probe X-ray microanalysis (EPMA). The trace element composition, heterogeneity and heavy metal speciation of individual particles was studied using synchrotron radiation-based microbeam X-ray emission and absorption methods. Particles were selected only from samples regarded as polluted sediment. White-beam micro X-ray fluorescence ({mu}-XRF) allowed the quantitative determination of heavy metals such as cadmium in individual particles. The maximum observed concentration of cadmium (>700 {mu}g/g) indicates that this highly toxic heavy metal is concentrated in individual anthropogenic particles. Using the combination of micro X-ray absorption near-edge structure and target-transformation principle component analysis, quantitative chemical speciation of copper and zinc was feasible on individual sediment particles. Heavy metals in most of the particles released from the pollution site remained in the sulfide form resulting in a limited mobility of these metals. Based on the information obtained using microanalytical methods, the estimation of the environmental mobility of heavy metals connected to microparticles becomes possible.

  10. Characterization of anthropogenic sediment particles after a transboundary water pollution of river Tisza using synchrotron radiation

    Science.gov (United States)

    Osán, János; Török, Szabina; Alföldy, Bálint; Falkenberg, Gerald

    2004-05-01

    At the beginning of 2000, a major mining accident occurred in the Romanian part of the Tisza catchment area due to tailings dam failure releasing huge amounts of heavy metals to the river. Sediment samples were taken from the main riverbed at six sites in Hungary, on March 16, 2000. The objective of this work was to characterize the anthropogenic particles in river sediment previously selected by single-particle electron probe X-ray microanalysis (EPMA). The trace element composition, heterogeneity and heavy metal speciation of individual particles was studied using synchrotron radiation-based microbeam X-ray emission and absorption methods. Particles were selected only from samples regarded as polluted sediment. White-beam micro X-ray fluorescence (μ-XRF) allowed the quantitative determination of heavy metals such as cadmium in individual particles. The maximum observed concentration of cadmium (>700 μg/g) indicates that this highly toxic heavy metal is concentrated in individual anthropogenic particles. Using the combination of micro X-ray absorption near-edge structure and target-transformation principle component analysis, quantitative chemical speciation of copper and zinc was feasible on individual sediment particles. Heavy metals in most of the particles released from the pollution site remained in the sulfide form resulting in a limited mobility of these metals. Based on the information obtained using microanalytical methods, the estimation of the environmental mobility of heavy metals connected to microparticles becomes possible.

  11. Characterization of anthropogenic sediment particles after a transboundary water pollution of river Tisza using synchrotron radiation

    International Nuclear Information System (INIS)

    At the beginning of 2000, a major mining accident occurred in the Romanian part of the Tisza catchment area due to tailings dam failure releasing huge amounts of heavy metals to the river. Sediment samples were taken from the main riverbed at six sites in Hungary, on March 16, 2000. The objective of this work was to characterize the anthropogenic particles in river sediment previously selected by single-particle electron probe X-ray microanalysis (EPMA). The trace element composition, heterogeneity and heavy metal speciation of individual particles was studied using synchrotron radiation-based microbeam X-ray emission and absorption methods. Particles were selected only from samples regarded as polluted sediment. White-beam micro X-ray fluorescence (μ-XRF) allowed the quantitative determination of heavy metals such as cadmium in individual particles. The maximum observed concentration of cadmium (>700 μg/g) indicates that this highly toxic heavy metal is concentrated in individual anthropogenic particles. Using the combination of micro X-ray absorption near-edge structure and target-transformation principle component analysis, quantitative chemical speciation of copper and zinc was feasible on individual sediment particles. Heavy metals in most of the particles released from the pollution site remained in the sulfide form resulting in a limited mobility of these metals. Based on the information obtained using microanalytical methods, the estimation of the environmental mobility of heavy metals connected to microparticles becomes possible

  12. Anthropogenic mercury emission inventory with emission factors and total emission in Korea

    Science.gov (United States)

    Kim, Jeong-Hun; Park, Jung-Min; Lee, Sang-Bo; Pudasainee, Deepak; Seo, Yong-Chil

    2010-07-01

    Mercury emissions concentrations, emission factors, and the total national emission from major anthropogenic sources in Korea for the year 2007 were estimated. Uncontrolled and controlled mercury emission factors and the total emission from each source types are presented. The annual national mercury emission from major anthropogenic sources for the year 2007, on average was 12.8 ton which ranged from 6.5 to 20.2 ton. Averaged emissions of elemental, oxidized, and particulate mercury were estimated at 8.25 ton, 3.69 ton, and 0.87 ton, respectively. Due to the removal of a major portion of particulate and oxidized mercury species, elemental mercury was dominant in stack emission. About 54.8% of mercury emission was contributed by industrial sources, 45.0% by stationary combustion sources and 0.02% by mobile sources. Thermal power plants, oil refineries, cement kilns and incinerators (municipal, industrial, medical, sewage sludge) were the major mercury emitters, contributing about 26%, 25%, 21% and 20%, respectively to the total mercury emission. Other sources (crematory, pulp and paper manufacturing, nonferrous metals manufacturing, glass manufacturing) contributed about 8% of the total emission. Priority should be given in controlling mercury emissions from coal-fired power plants, oil refineries, cement kilns and waste incinerators. More measurements including natural and re-emission sources are to be carried out in the future in order to have a clear scenario of mercury emission from the country and to apply effective control measures.

  13. Retrospective analysis of bottlenose dolphin foraging: a legacy of anthropogenic ecosystem disturbance

    Science.gov (United States)

    Rossman, Sam; Barros, Nélio B.; Ostrom, Peggy H.; Stricker, Craig A.; Hohn, Aleta A.; Gandhi, Hasand; Wells, Randall S.

    2013-01-01

    We used stable isotope analysis to investigate the foraging ecology of coastal bottlenose dolphins (Tursiops truncatus) in relation to a series of anthropogenic disturbances. We first demonstrated that stable isotopes are a faithful indicator of habitat use by comparing muscle isotope values to behavioral foraging data from the same individuals. δ13C values increased, while δ34S and δ15N values decreased with the percentage of feeding observations in seagrass habitat. We then utilized stable isotope values of muscle to assess temporal variation in foraging habitat from 1991 to 2010 and collagen from tooth crown tips to assess the time period 1944 to 2007. From 1991 to 2010, δ13C values of muscle decreased while δ34S values increased indicating reduced utilization of seagrass habitat. From 1944 to 1989 δ13C values of the crown tip declined significantly, likely due to a reduction in the coverage of seagrass habitat and δ15N values significantly increased, a trend we attribute to nutrient loading from a rapidly increasing human population. Our results demonstrate the utility of using marine mammal foraging habits to retrospectively assess the extent to which anthropogenic disturbance impacts coastal food webs.

  14. Anthropogenic Radio-Frequency Electromagnetic Fields Elicit Neuropathic Pain in an Amputation Model

    Science.gov (United States)

    Jones, Erick; Romero-Ortega, Mario

    2016-01-01

    Anecdotal and clinical reports have suggested that radio-frequency electromagnetic fields (RF EMFs) may serve as a trigger for neuropathic pain. However, these reports have been widely disregarded, as the epidemiological effects of electromagnetic fields have not been systematically proven, and are highly controversial. Here, we demonstrate that anthropogenic RF EMFs elicit post-neurotomy pain in a tibial neuroma transposition model. Behavioral assays indicate a persistent and significant pain response to RF EMFs when compared to SHAM surgery groups. Laser thermometry revealed a transient skin temperature increase during stimulation. Furthermore, immunofluorescence revealed an increased expression of temperature sensitive cation channels (TRPV4) in the neuroma bulb, suggesting that RF EMF-induced pain may be due to cytokine-mediated channel dysregulation and hypersensitization, leading to thermal allodynia. Additional behavioral assays were performed using an infrared heating lamp in place of the RF stimulus. While thermally-induced pain responses were observed, the response frequency and progression did not recapitulate the RF EMF effects. In vitro calcium imaging experiments demonstrated that our RF EMF stimulus is sufficient to directly contribute to the depolarization of dissociated sensory neurons. Furthermore, the perfusion of inflammatory cytokine TNF-α resulted in a significantly higher percentage of active sensory neurons during RF EMF stimulation. These results substantiate patient reports of RF EMF-pain, in the case of peripheral nerve injury, while confirming the public and scientific consensus that anthropogenic RF EMFs engender no adverse sensory effects in the general population. PMID:26760033

  15. Benthic Nutrient Fluxes from Mangrove Sediments of an Anthropogenically Impacted Estuary in Southern China

    Directory of Open Access Journals (Sweden)

    David Kaiser

    2015-06-01

    Full Text Available Mangroves serve as either sinks or sources for inorganic and organic nutrients and can mitigate anthropogenic nutrient pollution, control the production in adjacent systems, and prevent eutrophication. To better understand the nutrient dynamics in a subtropical mangrove, we employed a three-way approach in the Nanliu River Estuary, southern China: Pore water profiles and sediment incubations revealed benthic early diagenesis as well as sediment–water exchange of dissolved nutrients and oxygen, while tidal sampling of estuarine and mangrove water identified source and sink functions of the entire mangrove forest. Fluxes of oxygen during incubations were always directed into the sediment, indicating heterotrophy of the system. There was a net uptake of dissolved inorganic nitrogen, mainly caused by nitrate influx, while ammonium and nitrite showed variable flux direction. Despite high pore water concentrations, phosphate and silica showed net uptake. Fluxes of dissolved organic carbon were generally low except for high efflux in the dark following a storm event. Due to the combination of small forest area and strong anthropogenic nutrient input, the net sink function for dissolved nitrogen and phosphorus provides no significant buffer against the eutrophication of coastal waters.

  16. Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of the Colorado Front Range (USA)

    Science.gov (United States)

    Wolfe, A.P.; Baron, J.S.; Cornett, R.J.

    2001-01-01

    Recent sediments from two alpine lakes (> 3300 m asl) in the Colorado Front Range (USA) register marked and near-synchronous changes that are believed to represent ecological responses to enhanced atmospheric deposition of fixed nitrogen from anthropogenic sources. Directional shifts in sediment proxies include greater representations of mesotrophic diatoms and increasingly depleted ??15N values. These trends are particularly pronounced since ??? 1950, and appear to chronicle lake responses to excess N derived from agricultural and industrial sources to the east. The rate and magnitude of recent ecological changes far exceed the context of natural variability, as inferred from comparative analyses of a long core capturing the entire 14,000-year postglacial history of one of the lakes. Nitrogen deposition to these seemingly pristine natural areas has resulted in subtle but detectable limnological changes that likely represent the beginning of a stronger response to nitrogen enrichment.

  17. Sources and distribution of anthropogenic radionuclides in different marine environments

    International Nuclear Information System (INIS)

    The knowledge of the distribution in time and space radiologically important radionuclides from different sources in different marine environments is important for assessment of dose commitment following controlled or accidental releases and for detecting eventual new sources. Present sources from nuclear explosion tests, releases from nuclear facilities and the Chernobyl accident provide a tool for such studies. The different sources can be distinguished by different isotopic and radionuclide composition. Results show that radiocaesium behaves rather conservatively in the south and north Atlantic while plutonium has a residence time of about 8 years. On the other hand enhanced concentrations of plutonium in surface waters in arctic regions where vertical mixing is small and iceformation plays an important role. Significantly increased concentrations of plutonium are also found below the oxic layer in anoxic basins due to geochemical concentration. (author)

  18. Anthropogenic chemical carbon cycle for a sustainable future.

    Science.gov (United States)

    Olah, George A; Prakash, G K Surya; Goeppert, Alain

    2011-08-24

    Nature's photosynthesis uses the sun's energy with chlorophyll in plants as a catalyst to recycle carbon dioxide and water into new plant life. Only given sufficient geological time, millions of years, can new fossil fuels be formed naturally. The burning of our diminishing fossil fuel reserves is accompanied by large anthropogenic CO(2) release, which is outpacing nature's CO(2) recycling capability, causing significant environmental harm. To supplement the natural carbon cycle, we have proposed and developed a feasible anthropogenic chemical recycling of carbon dioxide. Carbon dioxide is captured by absorption technologies from any natural or industrial source, from human activities, or even from the air itself. It can then be converted by feasible chemical transformations into fuels such as methanol, dimethyl ether, and varied products including synthetic hydrocarbons and even proteins for animal feed, thus supplementing our food chain. This concept of broad scope and framework is the basis of what we call the Methanol Economy. The needed renewable starting materials, water and CO(2), are available anywhere on Earth. The required energy for the synthetic carbon cycle can come from any alternative energy source such as solar, wind, geothermal, and even hopefully safe nuclear energy. The anthropogenic carbon dioxide cycle offers a way of assuring a sustainable future for humankind when fossil fuels become scarce. While biosources can play a limited role in supplementing future energy needs, they increasingly interfere with the essentials of the food chain. We have previously reviewed aspects of the chemical recycling of carbon dioxide to methanol and dimethyl ether. In the present Perspective, we extend the discussion of the innovative and feasible anthropogenic carbon cycle, which can be the basis of progressively liberating humankind from its dependence on diminishing fossil fuel reserves while also controlling harmful CO(2) emissions to the atmosphere. We also

  19. Metals in pond sediments as archives of anthropogenic activities: a study in response to health concerns

    International Nuclear Information System (INIS)

    An environmental geochemistry approach was applied in response to health concerns about present day and past exposure to pollutants within Broome County, New York by determining historical records of anthropogenic activities as preserved in sediment cores. Sediment was collected from a stormwater retention pond adjacent to a warehouse complex in the urban community of Hillcrest as well as from 3 other ponds in rural locations in Broome County. Metal concentrations and decay products of 210Pb and 137Cs were measured to determine the timing of source specific differences in the distribution of metals in the sediment cores. Concentrations of Zn, Pb, Ni, Cu, Cr, Cd and As were elevated in the retention pond sediments when compared to sediment from other locations. Topography influenced atmospheric transport and deposition of pollutants within incised river valleys and enhanced runoff from impervious surfaces within an urban watershed contributed to the elevated metal concentrations at Hillcrest. Temporal changes in Pb deposition within retention pond sediment mimic the rise and fall in use of leaded gasoline. Arsenic concentrations decreased following placement of emission controls on nearby coal-fired power plant sources. Superimposed over the temporal trends of Pb and As are co-varying Zn, Ni, Cu, Cr and Cd concentrations; a suite of metals commonly used in metal plating processes by local industries. Analysis of sediment in stormwater retention ponds in other urban areas may provide opportunities for detailed records of pollution history to be obtained in many communities. Residents in urban communities located in incised river valley locations similar to Hillcrest may be particularly prone to enhanced exposure to metals from anthropogenic sources

  20. Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China

    Science.gov (United States)

    Wu, Jinglu; Abuduwaili, Jilili; Liu, Wen

    2016-01-01

    Geochemical concentrations were extracted for a short sediment core from Ebinur Lake, located in arid northwest China, and mathematical methods were used to demonstrate the complex pattern of the geochemical anomalies resulting from the temporal changes in natural and anthropogenic forces on the lake sediments. The first element assemblage (C1) (aluminum, potassium, iron, magnesium, beryllium, etc.) was predominantly terrigenous; among the assemblage, total phosphorus and titanium were generally consistent with aluminum except with regards to their surface sequences, which inferred the differences of source regions for terrigenous detrital material led to this change around ca. 2000AD. The second assemblage (C2) (calcium and strontium) was found to have a negative relationship with aluminum through a cluster analysis. The third assemblage (C3) included sodium and magnesium, which were influenced by the underwater lake environment and deposited in the Ebinur depression. The concentration ratio of C1/(C1+C2) was used as an indicator for denudation amount of detrital materials, which was supported by the values of magnetic susceptibility. The enrichment factors for heavy metals suggested that the influence of human activities on heavy-metal enrichment in Ebinur Lake region was not severe over the past century. Prior to the 1960s, geochemical indicators suggested a stable lacustrine environment with higher water levels. Beginning in the 1960s, high agricultural water demand resulted in rapid declines in lake water level, with subsequent increases of lake water salinity, as evidenced by enhanced sodium concentration in lake core sediments. During this period, anthropogenic activity also enhanced the intensity of weathering and the denudation of the Ebinur watershed. PMID:27176765

  1. Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China.

    Directory of Open Access Journals (Sweden)

    Long Ma

    Full Text Available Geochemical concentrations were extracted for a short sediment core from Ebinur Lake, located in arid northwest China, and mathematical methods were used to demonstrate the complex pattern of the geochemical anomalies resulting from the temporal changes in natural and anthropogenic forces on the lake sediments. The first element assemblage (C1 (aluminum, potassium, iron, magnesium, beryllium, etc. was predominantly terrigenous; among the assemblage, total phosphorus and titanium were generally consistent with aluminum except with regards to their surface sequences, which inferred the differences of source regions for terrigenous detrital material led to this change around ca. 2000AD. The second assemblage (C2 (calcium and strontium was found to have a negative relationship with aluminum through a cluster analysis. The third assemblage (C3 included sodium and magnesium, which were influenced by the underwater lake environment and deposited in the Ebinur depression. The concentration ratio of C1/(C1+C2 was used as an indicator for denudation amount of detrital materials, which was supported by the values of magnetic susceptibility. The enrichment factors for heavy metals suggested that the influence of human activities on heavy-metal enrichment in Ebinur Lake region was not severe over the past century. Prior to the 1960s, geochemical indicators suggested a stable lacustrine environment with higher water levels. Beginning in the 1960s, high agricultural water demand resulted in rapid declines in lake water level, with subsequent increases of lake water salinity, as evidenced by enhanced sodium concentration in lake core sediments. During this period, anthropogenic activity also enhanced the intensity of weathering and the denudation of the Ebinur watershed.

  2. Determination of medium time scale ionization effects at various altitudes in the stratosphere and troposphere during ground level enhancement due to solar cosmic rays on 13.12.2006 (GLE 70)

    International Nuclear Information System (INIS)

    Relativistic and sub-relativistic solar energetic particles could cause an excess of ionization in the atmosphere, specifically in polar and sub-polar regions. This effect is observed mainly in upper troposphere and lower and middle stratosphere. The ionization effect could be strong at short time scales during major ground level enhancements (GLE)s. However, for the aims of recent atmospheric physics and atmospheric chemistry studies, namely the influence on the minor constituents and aerosols, it is important to derive the medium time scale ionization effect at various altitudes above the sea level. The ground level enhancement GLE 70 on December of 13, 2006 is the third strongest event of the previous solar cycle 23. The ionization effect in the Earth atmosphere is obtained for various latitudes on the basis of a full Monte Carlo simulation of cosmic ray induced atmospheric cascade at several altitudes, namely 35km, 25km, 15km and 8km above the sea level. Here we adopt previously reported ion production rate profiles obtained with Monte Carlo simulation of atmospheric cascade performed with the CORSIKA 6.990 code using FLUKA 2011 and QGSJET II hadron generators. A realistic winter atmospheric model is assumed. The 24‑h ionization effect is computed for the sub-polar and polar regions, where it is expected to be the maximal effect of the planetary distribution on the Earth. Key words: galactic and solar cosmic rays, ground level enhancement, ionization model, atmospheric physics, atmospheric chemistry

  3. Anthropogenic impact on amorphous silica pools in temperate soils

    Directory of Open Access Journals (Sweden)

    W. Clymans

    2011-08-01

    Full Text Available Human land use changes perturb biogeochemical silica (Si cycling in terrestrial ecosystems. This directly affects Si mobilisation and Si storage and influences Si export from the continents, although the magnitude of the impact is unknown. A major reason for our lack of understanding is that very little information exists on how land use affects amorphous silica (ASi storage in soils. We have quantified and compared total alkali-extracted (PSia and easily soluble (PSie Si pools at four sites along a gradient of anthropogenic disturbance in southern Sweden. Land use clearly affects ASi pools and their distribution. Total PSia and PSie for a continuous forested site at Siggaboda Nature Reserve (66 900 ± 22 800 kg SiO2 ha−1 and 952 ± 16 kg SiO2 ha−1 are significantly higher than disturbed land use types from the Råshult Culture Reserve including arable land (28 800 ± 7200 kg SiO2 ha−1 and 239 ± 91 kg SiO2 ha−1, pasture sites (27 300 ± 5980 kg SiO2 ha−1 and 370 ± 129 kg SiO2 ha−1 and grazed forest (23 600 ± 6370 kg SiO2 ha−1 and 346 ± 123 kg SiO2 ha−1. Vertical PSia and PSie profiles show significant (p < 0.05 variation among the sites. These differences in size and distribution are interpreted as the long-term effect of reduced ASi replenishment, as well as changes in ecosystem specific pedogenic processes and increased mobilisation of the PSia in disturbed soils. We have also made a first, though rough, estimate of the magnitude of change in temperate continental ASi pools due to human disturbance. Assuming that our data are representative, we estimate that total ASi storage in soils has declined by ca. 10 % since the onset of agricultural development (3000 BCE

  4. Use of Pb and Sr isotopes as tracers of anthropogenic and natural inputs in rain waters and rivers of the Paris basin

    International Nuclear Information System (INIS)

    The isotopic composition of Pb and Sr, measured in the soluble phase of rain waters and rivers are used to determine and quantify the anthropogenic inputs and the weathering rates in the Seine basin. Atmospheric lead from rain waters is exclusively anthropogenic and is derived from gasoline and industrial emissions. These rain waters transfer lead, and certain other heavy metals, into the Seine, where the anthropogenic signal perturbs the natural geochemical cycle of these metals. This transfer to the river occurs principally in the city of Paris, in contrast, in the catchment area upstream of Paris, these elements are mainly trapped in soils, rather than transferred to the river. The anthropogenic inputs comprise three-quarters of the total transport of these metals by the Seine. In the river, lead transport is due to adsorption process occurring within the suspended load. Thus, soluble lead concentrations are linked to the river flow and the intensity of mechanical erosion. After correction for atmospheric and anthropogenic inputs, it is possible to estimate the silicate weathering rate for the Seine basin. This estimate is close to that obtained for large plain rivers, such as the Congo or Amazon, indicating that chemical erosion is linked to tectonic processes rather than climatic conditions. (author)

  5. Uplifting of carbon monoxide from biomass burning and anthropogenic sources to the free troposphere in East Asia

    Science.gov (United States)

    Ding, K.; Liu, J.; Ding, A.; Liu, Q.; Zhao, T. L.; Shi, J.; Han, Y.; Wang, H.; Jiang, F.

    2015-03-01

    East Asia has experienced rapid development with increasing carbon monoxide (CO) emission in the past decades. Therefore, uplifting CO from the boundary layer to the free troposphere in East Asia can have great implications on regional air quality around the world. It can also influence global climate due to the longer lifetime of CO at higher altitudes. In this study, three cases of high CO episodes in the East China Sea and the Sea of Japan from 2003 to 2005 are examined with spaceborne Measurements of Pollution in the Troposphere (MOPITT) data, in combination with aircraft measurements from the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program. High CO abundances of 300-550 ppbv are observed in MOZAIC data in the free troposphere during these episodes. These are among the highest CO abundances documented at these altitudes. On average, such episodes with CO over 400 ppbv (in the 2003 and 2004 cases) and between 200 and 300 ppbv (in the 2005 case) may occur 2-5 and 10-20% in time, respectively, in the respective altitudes over the region. Correspondingly, elevated CO is shown in MOPITT daytime data in the middle to upper troposphere in the 2003 case, in the lower to middle troposphere in the 2004 case, and in the upper troposphere in the 2005 case. Through analyses of the simulations from a chemical transport model GEOS-Chem and a trajectory dispersion model FLEXPART, we found different CO signatures in the elevated CO and distinct transport pathways and mechanisms for these cases. In the 2003 case, emissions from large forest fires near Lake Baikal dominated the elevated CO, which had been rapidly transported upward by a frontal system from the fire plumes. In the 2004 case, anthropogenic CO from the North China Plain experienced frontal lifting and mostly reached ~ 700 hPa near the East China Sea, while CO from biomass burning over Indochina experienced orographic lifting, lee-side-trough-induced convection, and frontal lifting

  6. "Lou soil", a fertile anthropogenic soil with thousands of years of cultivating history

    Science.gov (United States)

    Zhou, J.; Liang, B.; Yan, J.; Zhao, W.

    2012-12-01

    Chinese farmers have a very long history of using manures in their fields. Owing to the long-term addition of manures, an anthropogenic layer was formed on the top of original soil profile (drab soil) in Guanzhong Plains on the south edge of the Loess Plateau, North China. This soil is named the Manural Loessial soil (or Lou soil, "Lou" means the different stories of a building in Chinese). The depth of anthropogenic layer is in range of about 30 to 100 cm depth, which has a close relationship with the soil productivity. This fertile agricultural soil has sustained the agriculture in the region for millenniums. We had determined the organic carbon (SOC) in 7 soil profiles, and found that the depths of anthropogenic layer of were in range of 40 to 71 cm (averaging 59 cm). And the anthropogenic layer became shallower as the profile was far from the village due to less manure application. The organic C stocks in this layer accounted for 69% of organic C stocks in 0-100 cm soil profiles. Organic C stocks in Lou soil was higher than that in the newly cultivated soil developed from loess parent materials. Our 30-day incubation experiment found that addition of synthetic N fertilizer significantly increased the decomposition of SOC in the soils. However, The decomposition rate of SOC in the soil added with manure and inorganic fertilizers for 18-yr (MNPK soil) was significantly lower than in the soils added without fertilizer or inorganic fertilizers (NF soil, and NPK soils). The half-life of the organic C in MNPK soils was also slower than the NF soil, and NPK soil. It indicates that long-term combined application of manure and inorganic fertilizers improves the stabilization of soil organic C. Long-term cultivation has not only increased organic C stocks, but also stabilization of organic C in soil profile. It provides us a unique sample to study the mechanism of accumulation and stabilization of organic C in soil to balance agricultural production and C sequestration

  7. Substantial Contribution of Anthropogenic Air Pollution to Catastrophic Floods in Southwest China

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Jiwen; Rosenfeld, Daniel; Yang, Yan; Zhao, Chun; Leung, Lai-Yung R.; Li, Zhanqing

    2015-07-20

    Extreme events such as heat waves, floods, and droughts, have become more frequent since the 1950s1-2. This is likely caused through changes in greenhouse gases and aerosols that perturb the radiative balance and alter cloud processes3-8. On 8-9 July, 2013 a catastrophic flood devastated several metropolitan areas at the foothills of the Sichuan Basin. Using a high-resolution coupled atmosphere-chemistry model, we show that this disaster was not entirely natural. Ensemble simulations robustly show that the severe anthropogenic pollution in the Sichuan Basin significantly enhanced rainfall intensity over the mountainous area northwest of the basin. The heavy air pollution (mainly black carbon) absorbs solar radiation in the lower atmosphere at the expense of surface cooling, which stabilizes the atmosphere and suppresses convection and precipitation over the basin. The enhanced moisture and moist static energy over the basin are then transported by the prevailing winds towards the mountains during daytime. As the excessive moist air that reaches the foothills at night is orographically lifted, very strong convection develops and produces extremely heavy precipitation. Reducing black carbon (BC) emissions in the basin can effectively mitigate the extreme precipitation in the mountains. Unfortunately, BC emissions have been increasing in many developing countries including China9, making them more vulnerable to enhanced disasters as reported here.

  8. Influenza A(H1N1)pdm09 virus exhibiting enhanced cross-resistance to oseltamivir and peramivir due to a dual H275Y/G147R substitution, Japan, March 2016.

    Science.gov (United States)

    Takashita, Emi; Fujisaki, Seiichiro; Shirakura, Masayuki; Nakamura, Kazuya; Kishida, Noriko; Kuwahara, Tomoko; Shimazu, Yukie; Shimomura, Takeshi; Watanabe, Shinji; Odagiri, Takato

    2016-06-16

    An influenza A(H1N1)pdm09 virus carrying a G147R substitution in combination with an H275Y substitution in the neuraminidase protein, which confers cross-resistance to oseltamivir and peramivir, was detected from an immunocompromised inpatient in Japan, March 2016. This dual H275Y/G147R mutant virus exhibited enhanced cross-resistance to both drugs compared with the single H275Y mutant virus and reduced susceptibility to zanamivir, although it showed normal inhibition by laninamivir. PMID:27336226

  9. Anthropogenic greenhouse gas contribution to UK autumn flood risk

    Science.gov (United States)

    Pall, Pardeep; Aina, Tolu; Stone, Dáithí; Stott, Peter; Nozawa, Toru; Hilberts, Arno; Lohmann, Dag; Allen, Myles

    2010-05-01

    Interest in attributing the risk of damaging weather-related events to anthropogenic climate change is increasing[1]. Yet climate models typically used for studying the attribution problem do not resolve weather at scales causing damage[2]. Here we present the first multi-step study that attributes increasing risk of a damaging regional weather-related event to global anthropogenic greenhouse gas emissions. The event was the UK flooding of October and November 2000, occurring during the wettest autumn in England & Wales since records began in 1766[3] and inundating several river catchments[4]. Nearly 10,000 properties were flooded and transport services and power supplies severely disrupted, with insured losses estimated at £1.3bn[5,6]. Though the floods were deemed a ‘wake up call' to the impacts of climate change[7], anthropogenic drivers cannot be blamed for this individual event: but they could be blamed for changing its risk[8,9]. Indeed, typically quoted thermodynamic arguments do suggest increased probability of precipitation extremes under anthropogenic warming[10]. But these arguments are too simple[11,12,13] to fully account for the complex weather[4,14] associated with the flooding. Instead we use a Probabilistic Event Attribution framework, to rigorously estimate the contribution of anthropogenic greenhouse gas emissions to England & Wales Autumn 2000 flood risk. This involves comparing an unprecedented number of daily river runoff realisations for the region, under Autumn 2000 scenarios both with and without the emissions. These realisations are produced using publicly volunteered distributed computing power to generate several thousand seasonal forecast resolution climate model simulations[15,16] that are then fed into a precipitation-runoff model[17,18]. Autumn 2000 flooding is characterised by realisations exceeding the highest daily river runoff for that period, derived from the observational-based ERA-40 re-anaylsis[19]. We find that our

  10. Coastal Flooding Hazards due to storm surges and subsidence

    DEFF Research Database (Denmark)

    Sørensen, Carlo; Knudsen, Per; Andersen, Ole B.

    Flooding hazard and risk mapping are major topics in low-lying coastal areas before even considering the adverse effects of sea level rise (SLR) due to climate change. While permanent inundation may be a prevalent issue, more often floods related to extreme events (storm surges) have the largest...... damage potential.Challenges are amplified in some areas due to subsidence from natural and/or anthropogenic causes. Subsidence of even a few mm/y may over time greatly impair the safety against flooding of coastal communities and must be accounted for in order to accomplish the economically most viable...

  11. Measurement of anthropogenic radionuclides in the atmosphere with a radionuclide monitoring network for nuclear tests

    International Nuclear Information System (INIS)

    A worldwide radionuclide monitoring network for nuclear tests has detected the anthropogenic radioactive materials released in the atmosphere due to the accident of the Fukushima Daiichi Nuclear Power Plant impacted by the Great East Japan Earthquake on March 11, 2011. After four months have passed since the accident occurred, most overseas stations do not detect the radionuclides of Fukushima origin any more. The Takasaki station in Japan, however, is still detecting them every day. This paper describes radionuclide monitoring stations and the network of them as part of the International Monitoring System (IMS) in the Comprehensive Nuclear Test Ban Treaty (CTBT), as well as the measurement results of radionuclide particulates and radioactive isotopes of xenon released from the Fukushima Daiichi Nuclear Power Plant with the monitoring network. (J.P.N.)

  12. The effect of anthropogenic carbon monoxide on the methane budget of the troposphere

    Science.gov (United States)

    Chameides, W. L.

    1978-01-01

    Photochemical model calculations indicate that significant perturbations in tropospheric OH, CH4, and related compounds may occur in the coming decades due to increased anthropogenic emissions of CO and NO(x). The magnitude and direction of the perturbation depends on future emission rates of CO and NO(x) and also on the efficiency with which urban NO(x) is transported to the ambient atmosphere. If CO and NO(x) emissions increase at comparable rates, the CO effect on OH will dominate and OH will decrease while CH4 increases. The effects of a variation in tropospheric OH, halocarbons, and other compounds include a perturbation to stratospheric ozone and the atmosphere's thermal equilibrium.

  13. Impacts of anthropogenic activities on the Changjiang (Yangtze) estuarine ecosystem (1998-2012)

    Institute of Scientific and Technical Information of China (English)

    CHEN Dong; DAI Zhijun; XU Ren; LI Daoji; MEI Xuefei

    2015-01-01

    Estuarine ecosystem has greatly changed in the recent decades due to anthropogenic perturbations in the Changjiang Estuary. Change patterns and impact factors were analyzed based on the continuous data in relation to the Changjiang estuarine ecosystem from 1998 to 2012. The results showed significant decreases in plankton species and annual output ofCoilia nasus,Coilia mystus. Furthermore, species and biomass of benthos showed abrupt change in 2003, downward before that and upward after that. It was noted that,Eriocheir sinensis, a high value commercial fish, had an annual production increase of 97%. Reduction of riverine nutrients, especially dissolved silicate (DSI) loads into the estuary could contribute to the decline inBacillariophyta species. Dredging and dumping works of the North Passage led to the decreases in regional plankton species. However, the species reproduction and releasing projects could restore the estuarine ecosystem through increasing the output ofE. sinensis, as well as species and biomass of benthos.

  14. MODELING THE EFFECTS OF ANTHROPOGENIC SULFATE IN CLIMATE CHANGE BY USING A REGIONAL CLIMATE MODEL

    Institute of Scientific and Technical Information of China (English)

    高学杰; 林一骅; 赵宗慈

    2003-01-01

    Effects of aerosol with focus on the direct climate effect of anthropogenic sulfate aerosol under 2×CO2 condition were investigated by introducing aerosol distribution into the latest version of RegCM2. Two experiments, first run(2×CO2 + 0 aerosol concentration) and second run (2×CO2 + aerosol distribution), were made for 5 years respectively. Preliminary analysis shows that the direct climate effect of aerosol might cause a decrease of surface air temperature.The decrease might be larger in winter and in South China. The regional-averaged monthly precipitation might also decrease in most of the months due to the effect. The annual mean change of precipitation might be a decrease in East and an increase in West China. But the changes of both temperature and precipitation simulated were much smaller as compared to the greenhouse effect.

  15. Measuring Anthropogenic Sky Glow Using a Natural Sky Brightness Model

    Science.gov (United States)

    Duriscoe, Dan M.

    2013-11-01

    Anthropogenic sky glow (a result of light pollution) combines with the natural background brightness of the night sky when viewed by an observer on the earth's surface. In order to measure the anthropogenic component accurately, the natural component must be identified and subtracted. A model of the moonless natural sky brightness in the V-band was constructed from existing data on the Zodiacal Light, an airglow model based on the van Rhijn function, and a model of integrated starlight (including diffuse galactic light) constructed from images made with the same equipment used for sky brightness observations. The model also incorporates effective extinction by the atmosphere and is improved at high zenith angles (>80°) by the addition of atmospheric diffuse light. The model may be projected onto local horizon coordinates for a given observation at a resolution of 0.05° over the hemisphere of the sky, allowing it to be accurately registered with data images obtained from any site. Zodiacal Light and integrated starlight models compare favorably with observations from remote dark sky sites, matching within ± 8 nL over 95% of the sky. The natural airglow may be only approximately modeled, errors of up to ± 25 nL are seen when the airglow is rapidly changing or has considerable character (banding); ± 8 nL precision may be expected under favorable conditions. When subtracted from all-sky brightness data images, the model significantly improves estimates of sky glow from anthropogenic sources, especially at sites that experience slight to moderate light pollution.

  16. Anthropogenic heat flux estimation from space: first results

    Science.gov (United States)

    Chrysoulakis, Nektarios; Heldens, Wieke; Gastellu-Etchegorry, Jean-Philippe; Grimmond, Sue; Feigenwinter, Christian; Lindberg, Fredrik; Del Frate, Fabio; Klostermann, Judith; Mitraka, Zina; Esch, Thomas; Albitar, Ahmad; Gabey, Andrew; Parlow, Eberhard; Olofson, Frans

    2016-04-01

    While Earth Observation (EO) has made significant advances in the study of urban areas, there are several unanswered science and policy questions to which it could contribute. To this aim the recently launched Horizon 2020 project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites) investigates the potential of EO to retrieve anthropogenic heat flux, as a key component in the urban energy budget. The anthropogenic heat flux is the heat flux resulting from vehicular emissions, space heating and cooling of buildings, industrial processing and the metabolic heat release by people. Optical, thermal and SAR data from existing satellite sensors are used to improve the accuracy of the radiation balance spatial distribution calculation, using also in-situ reflectance measurements of urban materials are for calibration. EO-based methods are developed for estimating turbulent sensible and latent heat fluxes, as well as urban heat storage flux and anthropogenic heat flux spatial patterns at city scale and local scale by employing an energy budget closure approach. Independent methods and models are engaged to evaluate the derived products and statistical analyses provide uncertainty measures as well. Ultimate goal of the URBANFLUXES is to develop a highly automated method for estimating urban energy budget components to use with Copernicus Sentinel data, enabling its integration into applications and operational services. Thus, URBANFLUXES prepares the ground for further innovative exploitation of European space data in scientific activities (i.e. Earth system modelling and climate change studies in cities) and future and emerging applications (i.e. sustainable urban planning) by exploiting the improved data quality, coverage and revisit times of the Copernicus data. The URBANFLUXES products will therefore have the potential to support both sustainable planning strategies to improve the quality of life in cities, as well as Earth system models to

  17. Characterization of the Acoustic Field in Marine Environments with Anthropogenic Noise

    Science.gov (United States)

    Guan, Shane

    Most animals inhabit the aquatic environment are acoustical-oriented, due to the physical characteristics of water that favors sound transmission. Many aquatic animals depend on underwater sound to navigate, communicate, find prey, and avoid predators. The degradation of underwater acoustic environment due to human activities is expected to affected these animals' well-being and survival at the population level. This dissertation presents three original studies on the characteristics and behavior of underwater sound fields in three unique marine environments with anthropogenic noises. The first study examines the soundscape of the Chinese white dolphin habitat in Taiwan. Acoustic recordings were made at two coastal shallow water locations, Yunlin and Waisanding, in 2012. Results show that croaker choruses are dominant sound sources in the 1.2--2.4 kHz frequency band for both locations at night, and noises from container ships in the 150--300 Hz frequency band define the relative higher broadband sound levels at Yunlin. Results also illustrate interrelationships among different biotic, abiotic, and anthropogenic elements that shape the fine-scale soundscape in a coastal environment. The second study investigates the inter-pulse sound field during an open-water seismic survey in coastal shallow waters of the Arctic. The research uses continuous acoustic recordings collected from one bottom-mounted hydrophone deployed in the Beaufort Sea in summer 2012. Two quantitative methods were developed to examine the inter-pulse sound field characteristics and its dependence on source distances. Results show that inter-pulse sound field could raise the ambient noise floor by as much as 9 dB, depending on ambient condition and source distance. The third study examines the inter-ping sound field of simulated mid-frequency active sonar in deep waters off southern California in 2013 and 2014. The study used drifting acoustic recorder buoys to collect acoustic data during sonar

  18. Birth of a closed universe, and the anthropogenic principle

    International Nuclear Information System (INIS)

    A scenario is proposed for the evolution of the universe, starting with the quantum birth of a closed world at a minimum in the self-consistent de Sitter cosmological solution with vacuum polarization. The closure of the universe and the permanently supercritical value of its density follow directly from a single condition: that quantum birth take place. The perturbations must be small in order that the de Sitter phase may be sufficiently prolonged to ensure a protracted Friedmann plasma-matter expansion. Thus a universe having the properties we observe may in fact have been singled out by the anthropogenic principle

  19. Anthropogenic Radionuclides in Seawater of the Middle and Southern Adriatic Sea

    International Nuclear Information System (INIS)

    In the past few decades, the most studied radioisotopes in the Adriatic Sea have been Cs137 and Sr90, especially after the Chernobyl accident in 1986. On the contrary, the distribution of transuranic radionuclides in general in seawater of the Adriatic Sea is insufficiently explored due to low concentrations, absence of significant local sources and cumbersome radiochemical procedures for their determination. As a part of TC Project (RER/7/003) ''Marine Environmental Assessment of the Mediterranean Sea'' carried out by the IAEA, the International Scientific Cruise to the Adriatic and Ionian Seas was conducted in 2007. Samples of seawater collected during the scientific cruise were analyzed in the IAEA Marine Environment Laboratories in Monaco in 2009. The anthropogenic radionuclides 137Cs, 90Sr, 241Am and 239,240Pu were chosen as the most representative of anthropogenic radioactivity in the marine environment, comprising beta-, gamma- and alpha-emitters which have the highest potential contribution to radiation doses to humans via seafood consumption. This paper presents the results of the radionuclides distribution and behavior in the water column in the Jabuka Pit and South Adriatic Pit, and in the surface water of the inflowing and outflowing vein of the Otranto Strait. The vertical radionuclide profiles are different in the Jabuka Pit and South Adriatic Pit due to the different origin of dense water formation. In this report the first measured data for 239,240Pu and 241Am activity concentrations in the Adriatic Sea are presented. From the Adriatic cruise the average concentrations of the radionuclides in seawater are comparable to the literature data for the values of the Mediterranean Sea. The knowledge of radioactive contamination could be used for estimation of the environment condition and protection of the Adriatic Sea. (author)

  20. Anthropogenic Impact on the Non-closure of GRACE-based Water Budget in Hai River Basin, China

    Science.gov (United States)

    Pan, Y.; Zhang, C.; Yeh, P. J. F.; Gong, H.; Wang, X.

    2015-12-01

    The budget non-closure is commonly found in GRACE-based water budget (GRACE-WB) and usually explained as measurement errors. Since GRACE has a unique ability to detect the change of water storage both due to natural and anthropogenic factors, the non-closure needs to be investigated from not only measurement errors but also anthropogenic effects. The Hai River Basin (HRB) is selected as the study area to explore the relationship between the GRACE-WB non-closure and human modifications to water, including groundwater consumption and water diversion, with a considering of the outstanding feature of GRACE. The in situ measured precipitaion (P) and net runoff (R), together with evapotranspiration (E) from GLDAS land surface models (LSMs), are used to calculate the budget error between terrestrial water storage change (ΔTWS) derived from GRACE and P-E-R. It is found that the budget errors are comparable to bulletin reported water consumption and human modifications to water (groundwater use + water diversion), at annual and inter-annual scale, respectively. It is concluded that the GRACE-WB non-closure in HRB is dominated by the difference between LSM-simulated and GRACE-monitored water storage change resulted from anthropogenic use of water, which is usually not included in most LSMs but still seen by GRACE.

  1. Tracing the recently increasing anthropogenic Pb inputs into the East China Sea shelf sediments using Pb isotopic analysis

    International Nuclear Information System (INIS)

    Highlights: • Lithogenic Pb dominated in the ECS shelf sediments. • Small but increasing anthropogenic Pb occurred in the ECS shelf sediments. • HCl-leachated Pb suggested a source from “polluted” coastal sediments. • Residual Pb was mainly contributed from the “pristine” upper Yangtze watershed. - Abstract: This study examined the Pb content and Pb isotopic composition in a sediment core taken from the East China Sea (ECS) shelf, and it was observed that since 2003 the increasing anthropogenic Pb inputs have impacted as far as the ECS shelf sediments. The ECS shelf sediments were generally characterized with low bulk Pb contents (12.5–15.0 μg/g) and relatively lithogenic Pb isotopic signatures (both HCl-leached and residual fractions). However, elevated Pb records along with lighter Pb isotopic signals have occurred in the post-2003 sediments, as a result of a small but increasing anthropogenic Pb contribution from the heavily human perturbed coastal sediments due to the sharply increasing coal consumption in mainland China since 2003

  2. Anthropogenic and natural sources of acidity and metals and their influence on the structure of stream food webs

    International Nuclear Information System (INIS)

    We compared food web structure in 20 streams with either anthropogenic or natural sources of acidity and metals or circumneutral water chemistry in New Zealand. Community and diet analysis indicated that mining streams receiving anthropogenic inputs of acidic and metal-rich drainage had much simpler food webs (fewer species, shorter food chains, less links) than those in naturally acidic, naturally high metal, and circumneutral streams. Food webs of naturally high metal streams were structurally similar to those in mining streams, lacking fish predators and having few species. Whereas, webs in naturally acidic streams differed very little from those in circumneutral streams due to strong similarities in community composition and diets of secondary and top consumers. The combined negative effects of acidity and metals on stream food webs are clear. However, elevated metal concentrations, regardless of source, appear to play a more important role than acidity in driving food web structure. - Highlights: ► Food webs in acid mine drainage impacted streams are small and extremely simplified. ► Conductivity explained differences in food web properties between streams. ► Number of links and web size accounted for much dissimilarity between food webs. ► Food web structure was comparable in naturally acidic and circumneutral streams. - Food web structure differs in streams with anthropogenic and natural sources of acidity and metals.

  3. Sediment amino acids as indicators of anthropogenic activities and potential environmental risk in Erhai Lake, Southwest China.

    Science.gov (United States)

    Ni, Zhaokui; Wang, Shengrui; Zhang, Mianmian

    2016-05-01

    Total hydrolysable amino acids (THAAs) constitute the most important fraction of labile nitrogen. Anthropogenic activities directly influence various biogeochemical cycles and then accelerate lake ecosystem deterioration. This is the first study that has established the relationship between sediment THAAs and anthropogenic activities using dated sediment cores, and evaluated the possibility of THAAs release at the sediment interface based on changes in environmental conditions in Erhai Lake. The results showed that historical distribution and fractions of THAAs could be divided into three stages: a stable period before the 1970s, a clear increasing period from the 1970s to 1990s, and a gradually steady period that started after the 1990s. The chemical fraction, aromatic and sulfur amino acids (AAs) accounted for only ≤3% of THAAs. Basic AAs accounted for 5-17% of THAAs, and remained at a relatively stable level. However, acidic and neutral AAs, which accounted for 19-44% and 35-69% of THAAs, respectively, were the predominant factors causing THAAs to increase due to rapid agricultural intensification and intensification of contemporary sedimentation of phytoplankton or macrophytes since the 1970s. These trends were closely related to both anthropogenic activities and natural processes, which implied that sediment THAAs could act as an effective indicator that reflects anthropogenic activities and aquatic environmental characteristics. The current contributions of sediment THAAs on TN and TOC were <5% and 1.5%, respectively. However, the dramatic increase in THAAs in the sediment cores indicated that there was a huge potential source of labile nitrogen for the overlying water under certain environmental conditions. Correlation analysis suggested that the release of THAAs was negatively correlated with pH, whereas positively correlated with bacterial number and degree of OM mineralization, which particularly depend on the stability of HFOM. Therefore, the risk of

  4. Anthropogenic carbon dioxide in the Portland metropolitan region

    Science.gov (United States)

    Rice, A. L.; Bostrom, G. A.; Brooks, M. K.; Hill, L.; Shandas, V.

    2011-12-01

    The Portland metropolitan region, located in the Columbia River Gorge, is the most populous region in Oregon. Greenhouse gas emissions inventories for Multnomah County (population ~710k) estimate 2008 emissions to be 8.5 million metric tons carbon dioxide equivalent, of which CO2 is the dominant source. These inventories suggest that County-wide greenhouse gas emissions are near 1990 levels, despite a 22% growth in population. This contrasts with US National greenhouse gas emissions, which are estimated to have grown ~14% since 1990. Despite this apparent progress, there has been no validation of either emissions inventories for the Portland metropolitan region or their trends in time. We present more than two years of measurements of CO2 at three stationary locations in the Portland metropolitan region: a downtown location on the campus of Portland State University; a residential site in southeast Portland; and a rural station on Sauvie Island, located ~30km northwest of Portland in the Columbia River Gorge. Beginning in July 2009, continuous measurements of CO2 at the sites show considerable variability due to global and regional CO2 sources, sinks and boundary layer meteorology. Here we focus on the enhancement of in-city concentrations above the rural Sauvie Island site (CO2 excess), a difference which averages ~6ppm during upgorge wind conditions. The southeast Portland residential site shows a significant enhancement of ~5ppm in CO2 concentration throughout the day. The downtown site shows a substantial diurnal cycle in CO2 excess with 10-15ppm higher values during the day and negative values for CO2 excess during the early morning hours, the cause of which is not well understood. Both in-city sites show an increase in CO2 excess centered around 7-8 am and 5-6 pm during the two rush-hour periods. To examine spatial variability, measurements of street-level CO2 concentrations were obtained using a mobile instrument mounted in a bike trailer during a summer

  5. Large enhancement of magnetic anisotropy and laser induced resistive switching effect in La0.7Sr0.3MnO3 films due to strain from BaTiO3 substrates

    Science.gov (United States)

    Kalappattil, V.; Das, R.; Srikanth, H.; Phan, M. H.; Moya, X.

    Multifunctional oxide materials are interesting for their fundamental physical properties and technological applications. Epitaxial films of La0.7Sr0.3MnO3 (LSMO) on BaTiO3 (BTO) show intriguing properties such as a giant magnetoelectric effect due to strain from BTO substrate. The LSMO film shows sharp jumps in magnetization M(T) and resistance R(T) at first-order structural phase transitions of BTO (TR-O 200K and TO-T 270 K) due to strain coupling from BTO. A temperature evolution of effective in-plane anisotropy field (HK) measured using the radio-frequency transverse susceptibility (TS) shows a sharp increase in HK around TR-O, which vanishes around TO-T.The in-plane magnetic anisotropy plays an important role in changing the magnetic and resistive states around TO-T. A switchable laser-induced resistive change of up to 300 %, which is about 10 times greater than those of conventional oxide systems, has been achieved in LSMO films using a 0.5 W violet laser just below the TO-T.The repeatability and stability of the laser-induced resistive switching effect reveal potential applications of LSMO/BTO heterostructures in developing new type of temperature sensors and memory devices. Work at USF supported by ARO Grant No. W911NF-15-1-0626.

  6. Nuclear Renaissance in an Era of Anthropogenic Climate Change

    International Nuclear Information System (INIS)

    This paper substantiates the anthropogenic origin of climate change, demonstrates the resulting consequences, and thereby establishes the need for a nuclear renaissance over the next thirty years. First, the mechanisms behind the natural cycles in global warming, specifically, cycles of precession and eccentricity in Earth's orbit, as measured in ice cores, are compared to the mechanisms of anthropogenic warming, revealing the scientific basis for the observed correlation between carbon dioxide and temperature. Second, the resulting climate change is exemplified by key results from experiments performed by the author in the Arctic and at the South Geographic Pole, and the author's experience of Switzerland's costliest natural catastrophe - the flash flood of 2005. Third, although facing barriers such as research and development requirements, political will and public acceptance, the potential for nuclear power to triple to 1,000 GWe by 2050 would mitigate climate change by holding carbon dioxide concentration below 500 ppm, thereby challenging the younger nuclear generation to contribute to the most important issue facing humanity. (authors)

  7. Anthropogenic and geogenic impacts on arsenic bioaccessibility in UK topsoils.

    Science.gov (United States)

    Appleton, J D; Cave, M R; Wragg, J

    2012-10-01

    Predictive linear regression (LR) modelling between bioaccessible arsenic (B-As) and a range of total elemental compositions and soil properties was executed in order to assess the potential for developing a national B-As dataset for the UK. LR indicates that total arsenic (As) is the only highly significant independent variable for estimating B-As in urban areas where it explains 75-92% of the variance. The broad compatibility of the London, Glasgow and Swansea regression models suggests that application of these models to estimate bioaccessible As in UK soils impacted by diffuse anthropogenic urban contamination and non-ferrous metal processing should be relatively accurate. In areas dominated by Jurassic ironstones and associated clays and limestones, total As, P and pH are significant, accounting for 53, 14 and 5%, respectively, of the B-As variance. Models based on total As as the sole predictor in the combined Jurassic and Cretaceous sedimentary ironstones datasets explain about 40% of the B-As variance. The median As bioaccessible fraction (%As-BAF) is 19 to 28% in the anthropogenic contamination impacted urban domains, but much lower (5-9%) in geogenic terrains dominated by ironstones. Results of this study can be used as part of a lines of evidence approach to localised risk assessment but should not be used to replace bioaccessibility testing at individual sites where local conditions may vary considerably from the broad overview presented in this study. PMID:22842593

  8. Natural and anthropogenic hazards in karst areas of Albania

    Directory of Open Access Journals (Sweden)

    M. Parise

    2004-01-01

    Full Text Available In Albania, about one quarter of the country is occupied by outcroppings of soluble rocks; thus, karst represents an important and typical natural environment. Today karst areas are seriously threatened by a number of hazards, of both natural and anthropogenic origin. Many problems are related to agricultural practices: the use of heavy machinery, ever-increasing in recent years, results at many sites in destruction of the original karst landscapes. Use of pesticides and herbicides, in addition, causes the loss of karst ecosystems of great biological relevance, as has been observed in the Dumre district, where about 80 lakes of karst origin are present in the evaporites of Permian-Triassic age. Agricultural practice performed on slopes with medium to high gradient is a further factor which greatly predispose the slopes to erosion. The cave heritage of Albania (estimated so far in about 1000 caves is at risk because of the uncontrolled quarrying activities which determine the total or partial destruction of karst caves, including many of naturalistic, archaeological and speleological interest. Many caves have also become sites of illegal disposal of solid and liquid wastes, which causes pollution of the karst ecosystems and of the aquifer therein present, with heavy negative consequences on the quality of water. Even though most of the cases here mentioned are related to anthropogenic activities, the natural hazards, such as subsidence phenomena, floods, and the development of sinkholes, have not to be disregarded.

  9. Pathogenic enterobacteria in lemurs associated with anthropogenic disturbance.

    Science.gov (United States)

    Bublitz, DeAnna C; Wright, Patricia C; Rasambainarivo, Fidisoa T; Arrigo-Nelson, Summer J; Bodager, Jonathan R; Gillespie, Thomas R

    2015-03-01

    As human population density continues to increase exponentially, speeding the reduction and fragmentation of primate habitat, greater human-primate contact is inevitable, making higher rates of pathogen transmission likely. Anthropogenic effects are particularly evident in Madagascar, where a diversity of endemic lemur species are threatened by rapid habitat loss. Despite these risks, knowledge of how anthropogenic activities affect lemur exposure to pathogens is limited. To improve our understanding of this interplay, we non-invasively examined six species of wild lemurs in Ranomafana National Park for enteric bacterial pathogens commonly associated with diarrheal disease in human populations in Madagascar. Patterns of infection with Enterotoxigenic Escherichia coli, Shigella spp., Salmonella enterica, Vibrio cholerae, and Yersinia spp. (enterocolitica and pseudotuberculosis) were compared between lemurs inhabiting intact forest and lemurs inhabiting degraded habitat with frequent exposure to tourism and other human activity. Fecal samples acquired from humans, livestock, and rodents living near the degraded habitat were also screened for these bacteria. Remarkably, only lemurs living in disturbed areas of the park tested positive for these pathogens. Moreover, all of these pathogens were present in the human, livestock, and/or rodent populations. These data suggest that lemurs residing in forests altered or frequented by people, livestock, or peridomestic rodents, are at risk for infection by these diarrhea-causing enterobacteria and other similarly transmitted pathogens. PMID:25328106

  10. Spatial resolution of anthropogenic heat fluxes into urban aquifers.

    Science.gov (United States)

    Benz, Susanne A; Bayer, Peter; Menberg, Kathrin; Jung, Stephan; Blum, Philipp

    2015-08-15

    Urban heat islands in the subsurface contain large quantities of energy in the form of elevated groundwater temperatures caused by anthropogenic heat fluxes (AHFS) into the subsurface. The objective of this study is to quantify these AHFS and the heat flow they generate in two German cities, Karlsruhe and Cologne. Thus, statistical and spatial analytical heat flux models were developed for both cities. The models include the spatial representation of various sources of AHFS: (1) elevated ground surface temperatures, (2) basements, (3) sewage systems, (4) sewage leakage, (5) subway tunnels, and (6) district heating networks. The results show that the district heating networks induce the largest AHFS with values greater than 60 W/m(2) and one order of magnitude higher than fluxes from other sources. A covariance analysis indicates that the spatial distribution of the total flux depends mainly on the thermal gradient in the unsaturated zone. On a citywide scale, basements and elevated ground surface temperatures are the dominant sources of heat flow. Overall, 2.1 PJ/a and 1.0 PJ/a of heat are accumulated on average in Karlsruhe and the western part of Cologne, respectively. Extracting this anthropogenically originated energy could sustainably supply significant parts of the urban heating demand. Furthermore, using this heat could also keep groundwater temperatures from rising further. PMID:25930242

  11. Role of anthropogenic direct heat emissions in global warming

    CERN Document Server

    Wang, Fei; Zhao, Guangju; Gao, Peng; Li, Pengfei

    2015-01-01

    The anthropogenic emissions of greenhouse gases (GHG) are widely realized as the predominant drivers of global warming, but the huge and increasing anthropogenic direct heat emissions (AHE) has not gained enough attention in terms of its role in the warming of the climate system. Based on two reasonable assumptions of (1) AHE eventually transfers to the Earth energy system and (2) the net warming is only driven by the net radioactive forcing (RF) from either GHG or other causes, we analyzed the role of AHE in global warming. The mean annual total AHE of the four main sources including energy consumption, residual heat of electricity generation, biomass decomposition by land use and cover change (LUCC) and food consumption was estimated to be 4.41*10^20 J in 1970-2010, accounting for 6.23% of the net annual heat increase of the Earth reported by IPCC AR5 for the period. The mean annual radioactive forcing (RF) by AHE was up to 29.94 mW m^(-2) globally in 1981-2010, less than the annual net increase of total GH...

  12. Avoiding Dangerous Anthropogenic Interference with the Climate System

    Energy Technology Data Exchange (ETDEWEB)

    Keller, K. [Department of Geosciences, Penn State, PA (United States); Hall, M. [Brookings Institution, Washington, DC (United States); Kim, Seung-Rae [Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, NJ (United States); Bradford, D.F. [Department of Economics, Princeton University, Princeton, NJ (United States); Oppenheimer, M. [Woodrow Wilson School and Department of Geosciences, Princeton University, Robertson Hall 448, Princeton, NJ, 08544 (United States)

    2005-12-01

    The UN Framework Convention on Climate Change calls for the avoidance of 'dangerous anthropogenic interference with the climate system'. Among the many plausible choices, dangerous interference with the climate system may be interpreted as anthropogenic radiative forcing causing distinct and widespread climate change impacts such as a widespread demise of coral reefs or a disintegration of the West Antarctic ice sheet. The geological record and numerical models suggest that limiting global warming below critical temperature thresholds significantly reduces the likelihood of these eventualities. Here we analyze economically optimal policies that may ensure this risk-reduction. Reducing the risk of a widespread coral reef demise implies drastic reductions in greenhouse gas emissions within decades. Virtually unchecked greenhouse gas emissions to date (combined with the inertia of the coupled natural and human systems) may have already committed future societies to a widespread demise of coral reefs. Policies to reduce the risk of a West Antarctic ice sheet disintegration allow for a smoother decarbonization of the economy within a century and may well increase consumption in the long run.

  13. Detection of anthropogenic climate change using a fingerprint method

    Energy Technology Data Exchange (ETDEWEB)

    Hasselmann, K. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Bengtsson, L. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Cubasch, U. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Hegerl, G.C. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Rodhe, H. [Stockholm Univ. (Sweden). Dept. of Meteorology; Roeckner, E. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Storch, H. v. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Voss, R. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Waszkewitz, J. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany)

    1995-07-01

    A fingerprint method for detecting anthropogenic climate change is applied to new simulations with a coupled ocean-atmosphere general circulation model (CGCM) forced by increasing concentrations of greenhouse gases and aerosols covering the years 1880 to 2050. In addition to the anthropogenic climate change signal, the space-time structure of the natural climate variability for near-surface temperatures is estimated from instrumental data over the last 134 years and two 1000 year simulations with CGCMs. The estimates are compared with paleoclimate data over 570 years. The space-time information on both the signal and the noise is used to maximize the signal-to-noise ratio of a detection variable obtained by applying an optimal filter (fingerprint) to the observed data. The inclusion of aerosols slows the predicted future warming. The probability that the observed increase in near-surface temperatures in recent decades is of natural origin is estimated to be less than 5%. However, this number is dependent on the estimated natural variability level, which is still subject to some uncertainty. (orig.)

  14. Nuclear Renaissance in an Era of Anthropogenic Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Bird, John [Bruce Power, Box 3000 B06, Tiverton, Ontario N0G 2T0 (Canada)

    2008-07-01

    This paper substantiates the anthropogenic origin of climate change, demonstrates the resulting consequences, and thereby establishes the need for a nuclear renaissance over the next thirty years. First, the mechanisms behind the natural cycles in global warming, specifically, cycles of precession and eccentricity in Earth's orbit, as measured in ice cores, are compared to the mechanisms of anthropogenic warming, revealing the scientific basis for the observed correlation between carbon dioxide and temperature. Second, the resulting climate change is exemplified by key results from experiments performed by the author in the Arctic and at the South Geographic Pole, and the author's experience of Switzerland's costliest natural catastrophe - the flash flood of 2005. Third, although facing barriers such as research and development requirements, political will and public acceptance, the potential for nuclear power to triple to 1,000 GWe by 2050 would mitigate climate change by holding carbon dioxide concentration below 500 ppm, thereby challenging the younger nuclear generation to contribute to the most important issue facing humanity. (authors)

  15. Geochemical record of anthropogenic impacts on Lake Valencia, Venezuela

    International Nuclear Information System (INIS)

    Bulk geochemical parameters and organic matter biomarkers in a short, high resolution gravity core (Lake Valencia, Venezuela) were examined to reconstruct anthropogenic impacts on the lake's conditions. During the period of ca. 1840-1990, sedimentary organic matter was characterized by high contents of total organic C (TOC) and total N (TN), low TOC/TN values as well as relatively enriched δ13C and δ15N signals, suggesting a primary autochthonous (algae and macrophytes) organic matter origin. The occurrence of large amounts of C23 and C25 relative to C29 and C31n-alkanes indicated substantial inputs from submerged/floating macrophytes. The variations of C32 15-keto-ol, tetrahymanol, diploptene, C32 bishomohopanol, 2-methylhopane, dinosterol and isoarborinol concentrations over the investigated period record changes in the planktonic community structure, including Botryococcus braunii, bacteriavore ciliates, cyanobacteria, Eustigmatophytes and dinoflagellates. A principal shift occurred in the 1910s when cyanobacteria and dinoflagellates became more abundant at the expense and decline of B. braunii and Eustigmatophytes, likely related to increasing anthropogenic activity around the lake. A second shift (less obvious) occurred in the 1960s when cyanobacteria became the sole predominant planktonic class, coinciding with further deterioration of lake conditions

  16. Impact of increased anthropogenic atmospheric nitrogen deposition on ocean biogeochemistry

    Science.gov (United States)

    Yang, Simon; Gruber, Nicolas

    2015-04-01

    In the last century, the strong increase in anthropogenic emissions and agricultural activities brought about a tripling in atmospheric nitrogen deposition (AND) rates to oceans. There is growing evidence for a strong fingerprint of increased AND on aquatic systems. Increases in excess N over P (N*) have been attributed to the growing anthropogenically sourced N-deposition in the North western Pacific (Kim et al. 2011) and the North Pacific (Kim et al. 2014). In this study, we use the ocean component of the global earth system model CESM and forced it with transient atmospheric nitrogen deposition from 1850 to 2000 (Lamarque et al. 2013) to study the impact of increased N-deposition on ocean biogeochemistry. We simulate detectable signals in N* in the northern hemisphere as well as a complex pattern of increases and decreases in ocean productivity, with the former causing an expansion of oxygen minimum zones and an increase in water column denitrification. The increase in AND also reduces the ecological niches for N2-fixers, causing a substantial decrease in global ocean N-fixation. Despite this increase in N-loss by denitrification and decrease in N-gain by N-fixation, the increase in AND has put the global marine N-budget severely out of balance ( 10 TgN.yr-1). Finally, we extend our simulation to 2100 using the RCP 8.5 emission scenario to find that these changes will probably grow in the future.

  17. An emission inventory of sulfur from anthropogenic sources in Antarctica

    Science.gov (United States)

    Shirsat, S. V.; Graf, H. F.

    2009-05-01

    This paper presents first results of a comprehensive emission inventory of chemical species from anthropogenic activities (power generation, vehicles, ships and aircraft) in Antarctica, covering the 2004-2005 period. The inventory is based on estimated emission rates of fuel consumption provided by some of the Antarctic research stations. Since the emission sources have different modes of operation and use a variety of fuel, the emission flux rate of chemical species is calculated by multiplying the fuel consumption value with the density of fuel and appropriate emission factors. A separate inventory is prepared for each anthropogenic emission source in Antarctica. Depending on the type of operation, emission rates of SO2, and BC (Black Carbon, from shipping only) have been calculated using the above technique. However, only results of SO2 emissions from each source are presented here. Emission inventory maps of SO2 depicting the track/path taken by each mobile source are shown. The total annual SO2 is 158 Mg from power generation and vehicle operations, 3873 Mg from ships and 56 Mg from aircraft for 2004-2005 and these values undergo strong seasonality following the human activity in Antarctica. Though these figures are small when compared to the emissions at most other regions of the world, they are an indication that human presence in Antarctica leads to at least local pollution. The sources are mainly line and point sources and thus the local pollution potentially is relatively strong.

  18. Aerosol size distribution and radiative forcing response to anthropogenically driven historical changes in biogenic secondary organic aerosol formation

    Directory of Open Access Journals (Sweden)

    S. D. D'Andrea

    2014-10-01

    Full Text Available Emissions of biogenic volatile organic compounds (BVOC have changed in the past millennium due to changes in land use, temperature and CO2 concentrations. Recent model reconstructions of BVOC emissions over the past millennium predicted changes in dominant secondary organic aerosol (SOA producing BVOC classes (isoprene, monoterpenes and sesquiterpenes. The reconstructions predicted that global isoprene emissions have decreased (land-use changes to crop/grazing land dominate the reduction, while monoterpene and sesquiterpene emissions have increased (temperature increases dominate the increases; however, all three show regional variability due to competition between the various influencing factors. These BVOC changes have largely been anthropogenic in nature, and land-use change was shown to have the most dramatic effect by decreasing isoprene emissions. In this work, we use two modeled estimates of BVOC emissions from the years 1000 to 2000 to test the effect of anthropogenic changes to BVOC emissions on SOA formation, global aerosol size distributions, and radiative effects using the GEOS-Chem-TOMAS global aerosol microphysics model. With anthropogenic emissions (e.g. SO2, NOx, primary aerosols held at present day values and BVOC emissions changed from year 1000 to year 2000 values, decreases in the number concentration of particles of size Dp > 80 nm (N80 of >25% in year 2000 relative to year 1000 were predicted in regions with extensive land-use changes since year 1000 which led to regional increases in direct plus indirect aerosol radiative effect of >0.5 W m−2 in these regions. We test the sensitivity of our results to BVOC emissions inventory, SOA yields and the presence of anthropogenic emissions; however, the qualitative response of the model to historic BVOC changes remains the same in all cases. Accounting for these uncertainties, we estimate millennial changes in BVOC emissions cause a global mean direct effect of between +0.022 and

  19. Anthropogenic Habitats Facilitate Dispersal of an Early Successional Obligate: Implications for Restoration of an Endangered Ecosystem.

    Science.gov (United States)

    Amaral, Katrina E; Palace, Michael; O'Brien, Kathleen M; Fenderson, Lindsey E; Kovach, Adrienne I

    2016-01-01

    Landscape modification and habitat fragmentation disrupt the connectivity of natural landscapes, with major consequences for biodiversity. Species that require patchily distributed habitats, such as those that specialize on early successional ecosystems, must disperse through a landscape matrix with unsuitable habitat types. We evaluated landscape effects on dispersal of an early successional obligate, the New England cottontail (Sylvilagus transitionalis). Using a landscape genetics approach, we identified barriers and facilitators of gene flow and connectivity corridors for a population of cottontails in the northeastern United States. We modeled dispersal in relation to landscape structure and composition and tested hypotheses about the influence of habitat fragmentation on gene flow. Anthropogenic and natural shrubland habitats facilitated gene flow, while the remainder of the matrix, particularly development and forest, impeded gene flow. The relative influence of matrix habitats differed between study areas in relation to a fragmentation gradient. Barrier features had higher explanatory power in the more fragmented site, while facilitating features were important in the less fragmented site. Landscape models that included a simultaneous barrier and facilitating effect of roads had higher explanatory power than models that considered either effect separately, supporting the hypothesis that roads act as both barriers and facilitators at all spatial scales. The inclusion of LiDAR-identified shrubland habitat improved the fit of our facilitator models. Corridor analyses using circuit and least cost path approaches revealed the importance of anthropogenic, linear features for restoring connectivity between the study areas. In fragmented landscapes, human-modified habitats may enhance functional connectivity by providing suitable dispersal conduits for early successional specialists. PMID:26954014

  20. Anthropogenic Habitats Facilitate Dispersal of an Early Successional Obligate: Implications for Restoration of an Endangered Ecosystem.

    Directory of Open Access Journals (Sweden)

    Katrina E Amaral

    Full Text Available Landscape modification and habitat fragmentation disrupt the connectivity of natural landscapes, with major consequences for biodiversity. Species that require patchily distributed habitats, such as those that specialize on early successional ecosystems, must disperse through a landscape matrix with unsuitable habitat types. We evaluated landscape effects on dispersal of an early successional obligate, the New England cottontail (Sylvilagus transitionalis. Using a landscape genetics approach, we identified barriers and facilitators of gene flow and connectivity corridors for a population of cottontails in the northeastern United States. We modeled dispersal in relation to landscape structure and composition and tested hypotheses about the influence of habitat fragmentation on gene flow. Anthropogenic and natural shrubland habitats facilitated gene flow, while the remainder of the matrix, particularly development and forest, impeded gene flow. The relative influence of matrix habitats differed between study areas in relation to a fragmentation gradient. Barrier features had higher explanatory power in the more fragmented site, while facilitating features were important in the less fragmented site. Landscape models that included a simultaneous barrier and facilitating effect of roads had higher explanatory power than models that considered either effect separately, supporting the hypothesis that roads act as both barriers and facilitators at all spatial scales. The inclusion of LiDAR-identified shrubland habitat improved the fit of our facilitator models. Corridor analyses using circuit and least cost path approaches revealed the importance of anthropogenic, linear features for restoring connectivity between the study areas. In fragmented landscapes, human-modified habitats may enhance functional connectivity by providing suitable dispersal conduits for early successional specialists.

  1. Anthropogenic Methane Emissions in California's San Joaquin Valley: Characterizing Large Point Source Emitters

    Science.gov (United States)

    Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Holland, L.; Hook, S. J.; Hulley, G. C.; Johnson, W. R.; Kuai, L.; Kuwayama, T.; Lin, J. C.; Thorpe, A. K.; Worden, J. R.; Lauvaux, T.; Jeong, S.; Fischer, M. L.

    2015-12-01

    Methane is an important atmospheric pollutant that contributes to global warming and tropospheric ozone production. Methane mitigation could reduce near term climate change and improve air quality, but is hindered by a lack of knowledge of anthropogenic methane sources. Recent work has shown that methane emissions are not evenly distributed in space, or across emission sources, suggesting that a large fraction of anthropogenic methane comes from a few "super-emitters." We studied the distribution of super-emitters in California's southern San Joaquin Valley, where elevated levels of atmospheric CH4 have also been observed from space. Here, we define super-emitters as methane plumes that could be reliably detected (i.e., plume observed more than once in the same location) under varying wind conditions by airborne thermal infrared remote sensing. The detection limit for this technique was determined to be 4.5 kg CH4 h-1 by a controlled release experiment, corresponding to column methane enhancement at the point of emissions greater than 20% above local background levels. We surveyed a major oil production field, and an area with a high concentration of large dairies using a variety of airborne and ground-based measurements. Repeated airborne surveys (n=4) with the Hyperspectral Thermal Emission Spectrometer revealed 28 persistent methane plumes emanating from oil field infrastructure, including tanks, wells, and processing facilities. The likelihood that a given source type was a super-emitter varied from roughly 1/3 for processing facilities to 1/3000 for oil wells. 11 persistent plumes were detected in the dairy area, and all were associated with wet manure management. The majority (11/14) of manure lagoons in the study area were super-emitters. Comparing to a California methane emissions inventory for the surveyed areas, we estimate that super-emitters comprise a minimum of 9% of inventoried dairy emissions, and 13% of inventoried oil emissions in this region.

  2. Shedding light on light: benefits of anthropogenic illumination to a nocturnally foraging shorebird.

    Science.gov (United States)

    Dwyer, Ross G; Bearhop, Stuart; Campbell, Hamish A; Bryant, David M

    2013-03-01

    Intertidal habitats provide important feeding areas for migratory shorebirds. Anthropogenic developments along coasts can increase ambient light levels at night across adjacent inter-tidal zones. Here, we report the effects of elevated nocturnal light levels upon the foraging strategy of a migratory shorebird (common redshank Tringa totanus) overwintering on an industrialised estuary in Northern Europe. To monitor behaviour across the full intertidal area, individuals were located by day and night using VHF transmitters, and foraging behaviour was inferred from inbuilt posture sensors. Natural light was scored using moon-phase and cloud cover information and nocturnal artificial light levels were obtained using geo-referenced DMSP/OLS night-time satellite imagery at a 1-km resolution. Under high illumination levels, the commonest and apparently preferred foraging behaviour was sight-based. Conversely, birds feeding in areas with low levels of artificial light had an elevated foraging time and fed by touch, but switched to visual rather than tactile foraging behaviour on bright moonlit nights in the absence of cloud cover. Individuals occupying areas which were illuminated continuously by lighting from a large petrochemical complex invariably exhibited a visually based foraging behaviour independently of lunar phase and cloud cover. We show that ambient light levels affect the timing and distribution of foraging opportunities for redshank. We argue that light emitted from an industrial complex improved nocturnal visibility. This allowed sight-based foraging in place of tactile foraging, implying both a preference for sight-feeding and enhanced night-time foraging opportunities under these conditions. The study highlights the value of integrating remotely sensed data and telemetry techniques to assess the effect of anthropogenic change upon nocturnal behaviour and habitat use. PMID:23190422

  3. A reactive transport model for mercury fate in soil--application to different anthropogenic pollution sources.

    Science.gov (United States)

    Leterme, Bertrand; Blanc, Philippe; Jacques, Diederik

    2014-11-01

    Soil systems are a common receptor of anthropogenic mercury (Hg) contamination. Soils play an important role in the containment or dispersion of pollution to surface water, groundwater or the atmosphere. A one-dimensional model for simulating Hg fate and transport for variably saturated and transient flow conditions is presented. The model is developed using the HP1 code, which couples HYDRUS-1D for the water flow and solute transport to PHREEQC for geochemical reactions. The main processes included are Hg aqueous speciation and complexation, sorption to soil organic matter, dissolution of cinnabar and liquid Hg, and Hg reduction and volatilization. Processes such as atmospheric wet and dry deposition, vegetation litter fall and uptake are neglected because they are less relevant in the case of high Hg concentrations resulting from anthropogenic activities. A test case is presented, assuming a hypothetical sandy soil profile and a simulation time frame of 50 years of daily atmospheric inputs. Mercury fate and transport are simulated for three different sources of Hg (cinnabar, residual liquid mercury or aqueous mercuric chloride), as well as for combinations of these sources. Results are presented and discussed with focus on Hg volatilization to the atmosphere, Hg leaching at the bottom of the soil profile and the remaining Hg in or below the initially contaminated soil layer. In the test case, Hg volatilization was negligible because the reduction of Hg(2+) to Hg(0) was inhibited by the low concentration of dissolved Hg. Hg leaching was mainly caused by complexation of Hg(2+) with thiol groups of dissolved organic matter, because in the geochemical model used, this reaction only had a higher equilibrium constant than the sorption reactions. Immobilization of Hg in the initially polluted horizon was enhanced by Hg(2+) sorption onto humic and fulvic acids (which are more abundant than thiols). Potential benefits of the model for risk management and remediation of

  4. Human due diligence.

    Science.gov (United States)

    Harding, David; Rouse, Ted

    2007-04-01

    Most companies do a thorough job of financial due diligence when they acquire other companies. But all too often, deal makers simply ignore or underestimate the significance of people issues in mergers and acquisitions. The consequences are severe. Most obviously, there's a high degree of talent loss after a deal's announcement. To make matters worse, differences in decision-making styles lead to infighting; integration stalls; and productivity declines. The good news is that human due diligence can help companies avoid these problems. Done early enough, it helps acquirers decide whether to embrace or kill a deal and determine the price they are willing to pay. It also lays the groundwork for smooth integration. When acquirers have done their homework, they can uncover capability gaps, points of friction, and differences in decision making. Even more important, they can make the critical "people" decisions-who stays, who goes, who runs the combined business, what to do with the rank and file-at the time the deal is announced or shortly thereafter. Making such decisions within the first 30 days is critical to the success of a deal. Hostile situations clearly make things more difficult, but companies can and must still do a certain amount of human due diligence to reduce the inevitable fallout from the acquisition process and smooth the integration. This article details the steps involved in conducting human due diligence. The approach is structured around answering five basic questions: Who is the cultural acquirer? What kind of organization do you want? Will the two cultures mesh? Who are the people you most want to retain? And how will rank-and-file employees react to the deal? Unless an acquiring company has answered these questions to its satisfaction, the acquisition it is making will be very likely to end badly. PMID:17432159

  5. Impact of anthropogenic emission on air-quality over a megacity – revealed from an intensive atmospheric campaign during the Chinese Spring Festival

    Directory of Open Access Journals (Sweden)

    C. Deng

    2012-07-01

    Full Text Available The Chinese Spring Festival is one of the most important traditional festivals in China. The peak transport in the Spring Festival season (spring travel rush provides a unique opportunity for investigating the impact of human activities on air quality in the Chinese megacities as emission sources varied and fluctuated greatly prior to, during and after the festival. Enhanced vehicular emission during the spring travel rush before the festival resulted in high level pollutants of NOx (270 μg m−3, CO (2572 μg m−3, BC (8.5 μg m−3 and extremely low single scattering albedo of 0.70, indicating strong fresh combustion. Organics contributed most to PM2.5, followed by NO3−, NH4+, and SO42−. During the Chinese Lunar New Year's Eve and Day, widespread usage of fireworks burning caused heavy pollution of extremely high aerosol mass concentration, scattering coefficient, SO2 and NOx. Due to the spring travel rush after the festival, anthropogenic emission gradually climbed and mirrored corresponding increases in the aerosol components and gaseous pollutants. Secondary inorganic aerosol (SO42−, NO3−, and NH4+ accounted for a dominant fraction of 74% in PM2.5 due to the enhanced human activities, e.g. higher demand of energy usage from returned residents and re-open of factories and construction sites, more vehicle mileages due to returned workers and expanded public transportation. The average visibility during whole study period was less than 6 km. It was estimated that about 50% of the total light extinction was due to the high water vapor in the atmosphere. Of the aerosol extinction, organic aerosol had the largest contribution of 47%, followed by sulfate ammonium, nitrate ammonium and EC of 22%, 14%, and 12%, respectively. Our results indicated the dominant role of traffic-related aerosol species (i.e. organic aerosol, nitrate and EC on the formation of air pollution, and suggested the importance of controlling vehicle numbers and

  6. Impact of anthropogenic emission on air-quality over a megacity - revealed from an intensive atmospheric campaign during the Chinese Spring Festival

    Science.gov (United States)

    Huang, K.; Zhuang, G.; Lin, Y.; Wang, Q.; Fu, J. S.; Zhang, R.; Li, J.; Deng, C.; Fu, Q.

    2012-07-01

    The Chinese Spring Festival is one of the most important traditional festivals in China. The peak transport in the Spring Festival season (spring travel rush) provides a unique opportunity for investigating the impact of human activities on air quality in the Chinese megacities as emission sources varied and fluctuated greatly prior to, during and after the festival. Enhanced vehicular emission during the spring travel rush before the festival resulted in high level pollutants of NOx (270 μg m-3), CO (2572 μg m-3), BC (8.5 μg m-3) and extremely low single scattering albedo of 0.70, indicating strong fresh combustion. Organics contributed most to PM2.5, followed by NO3-, NH4+, and SO42-. During the Chinese Lunar New Year's Eve and Day, widespread usage of fireworks burning caused heavy pollution of extremely high aerosol mass concentration, scattering coefficient, SO2 and NOx. Due to the spring travel rush after the festival, anthropogenic emission gradually climbed and mirrored corresponding increases in the aerosol components and gaseous pollutants. Secondary inorganic aerosol (SO42-, NO3-, and NH4+) accounted for a dominant fraction of 74% in PM2.5 due to the enhanced human activities, e.g. higher demand of energy usage from returned residents and re-open of factories and construction sites, more vehicle mileages due to returned workers and expanded public transportation. The average visibility during whole study period was less than 6 km. It was estimated that about 50% of the total light extinction was due to the high water vapor in the atmosphere. Of the aerosol extinction, organic aerosol had the largest contribution of 47%, followed by sulfate ammonium, nitrate ammonium and EC of 22%, 14%, and 12%, respectively. Our results indicated the dominant role of traffic-related aerosol species (i.e. organic aerosol, nitrate and EC) on the formation of air pollution, and suggested the importance of controlling vehicle numbers and emissions in mega-cities of China

  7. Natural and anthropogenic sources and processes affecting water chemistry in two South Korean streams

    International Nuclear Information System (INIS)

    Acid mine drainage (AMD) in a watershed provides potential sources of pollutants for surface and subsurface waters that can deteriorate water quality. Between March and early August 2011, water samples were collected from two streams in South Korea, one dominantly draining a watershed with carbonate bedrock affected by coal mines and another draining a watershed with silicate bedrock and a relatively undisturbed catchment area. The objective of the study was to identify the sources and processes controlling water chemistry, which was dependent on bedrock and land use. In the Odae stream (OS), the stream in the silicate-dominated catchment, Ca, Na, and HCO3 were the dominant ions and total dissolved solids (TDS) was low (26.1–165 mg/L). In the Jijang stream (JS), in the carbonate-dominated watershed, TDS (224–434 mg/L) and ion concentrations were typically higher, and Ca and SO4 were the dominant ions due to carbonate weathering and oxidation of pyrite exposed at coal mines. Dual isotopic compositions of sulfate (δ34SSO4 and δ18OSO4) verified that the SO4 in JS is derived mainly from sulfide mineral oxidation in coal mines. Cl in JS was highest upstream and decreased progressively downstream, which implies that pollutants from recreational facilities in the uppermost part of the catchment are the major source governing Cl concentrations within the discharge basin. Dual isotopic compositions of nitrate (δ15NNO3 and δ18ONO3) indicated that NO3 in JS is attributable to nitrification of soil organic matter but that NO3 in OS is derived mostly from manure. Additionally, the contributions of potential anthropogenic sources to the two streams were estimated in more detail by using a plot of δ34SSO4 and δ15NNO3. This study suggests that the dual isotope approach for sulfate and nitrate is an excellent additional tool for elucidating the sources and processes controlling the water chemistry of streams draining watersheds having different lithologies and land

  8. Monitoring natural and anthropogenic induced variations in water availability across Africa

    Science.gov (United States)

    Ahmed, M.; Sultan, M.; Wahr, J. M.; Yan, E.

    2014-12-01

    Africa, the second-driest continent in the world after Australia, is one of the most vulnerable continents to climate change. Understanding the impacts of climatic and anthropogenic factors on Africa's hydrologic systems is vital for the assessment and utilization of Africa's water resources. In this study, we utilize the Gravity Recovery and Climate Experiment (GRACE) and land surface models (LSM; GLDAS and CLM4.5) in conjunction with other readily-available temporal climatic and remote sensing, geological and hydrological datasets for monitoring the spatial and temporal trends in Terrestrial Water Storage (TWS) over a time period of 10 years (01/2003-12/2012) over the African continent and to investigate the nature (e.g., climatic and/or human pressures-related) of, and the controlling factors causing, these variations. Spatial and temporal (i.e., time series analysis) correlations of the trends extracted from GRACE-derived (TWSGRACE) and LSM-derived (TWSLSM) TWS indicate the following: (1) Large (≥ 90 % by area) sectors of Africa are undergoing statistically significant TWSGRACE and TWSLSM variations due to natural and anthropogenic causes; (2) a general correspondence between TWSGRACE and TWSLSM over areas (e.g., Niger and Mozambique NE basins in eastern and western Africa) largely controlled by natural (i.e., increase/decrease in precipitation and/or temperature) causes; (3) discrepancies are observed over areas that witnessed extensive anthropogenic effects measured by TWSGRACE but unaccounted for by TWSLSM. Examples include: (a) strong (compared to that observed by TWSLSM) negative TWSGRACE trends were observed over areas that witnessed heavy groundwater extraction (e.g., Western, Desert, Egypt); (b) strong (compared to that observed by TWSLSM) positive TWSGRACE over Lake Volta reservoir; and (c) strong (compared to that observed by TWSLSM) negative trends over areas undergoing heavy deforestation (e.g., northern and NW Congo Basin); (4) additional

  9. Hunting, Exotic Carnivores, and Habitat Loss: Anthropogenic Effects on a Native Carnivore Community, Madagascar

    Science.gov (United States)

    Farris, Zach J.; Golden, Christopher D.; Karpanty, Sarah; Murphy, Asia; Stauffer, Dean; Ratelolahy, Felix; Andrianjakarivelo, Vonjy; Holmes, Christopher M.; Kelly, Marcella J.

    2015-01-01

    The wide-ranging, cumulative, negative effects of anthropogenic disturbance, including habitat degradation, exotic species, and hunting, on native wildlife has been well documented across a range of habitats worldwide with carnivores potentially being the most vulnerable due to their more extinction prone characteristics. Investigating the effects of anthropogenic pressures on sympatric carnivores is needed to improve our ability to develop targeted, effective management plans for carnivore conservation worldwide. Utilizing photographic, line-transect, and habitat sampling, as well as landscape analyses and village-based bushmeat hunting surveys, we provide the first investigation of how multiple forms of habitat degradation (fragmentation, exotic carnivores, human encroachment, and hunting) affect carnivore occupancy across Madagascar’s largest protected area: the Masoala-Makira landscape. We found that as degradation increased, native carnivore occupancy and encounter rates decreased while exotic carnivore occupancy and encounter rates increased. Feral cats (Felis species) and domestic dogs (Canis familiaris) had higher occupancy than half of the native carnivore species across Madagascar’s largest protected landscape. Bird and small mammal encounter rates were negatively associated with exotic carnivore occupancy, but positively associated with the occupancy of four native carnivore species. Spotted fanaloka (Fossa fossana) occupancy was constrained by the presence of exotic feral cats and exotic small Indian civet (Viverricula indica). Hunting was intense across the four study sites where hunting was studied, with the highest rates for the small Indian civet (x¯ = 90 individuals consumed/year), the ring-tailed vontsira (Galidia elegans) (x¯ = 58 consumed/year), and the fosa (Cryptoprocta ferox) (x¯ = 31 consumed/year). Our modeling results suggest hunters target intact forest where carnivore occupancy, abundance, and species richness, are

  10. Mercury emissions to the atmosphere from natural and anthropogenic sources in the Mediterranean region

    Science.gov (United States)

    Pirrone, N.; Costa, P.; Pacyna, J. M.; Ferrara, R.

    This report discusses past, current and projected mercury emissions to the atmosphere from major industrial sources, and presents a first assessment of the contribution to the regional mercury budget from selected natural sources. Emissions (1995 estimates) from fossil fuels combustion (29.8 t yr -1) , cement production (28.8 t yr -1) and incineration of solid wastes (27.6 t yr -1) , all together account for about 82% of the regional anthropogenic total (105.7 t yr -1) . Other industrial sources in the region are smelters (4.8 t yr -1) , iron-steel plants (4.8 t yr -1) and other minor sources (chlor-alkali plants, crematoria, chemicals production) that have been considered together in the miscellaneous category (9.6 t yr -1) . Regional emissions from anthropogenic sources increased at a rate of 3% yr-1 from 1983 to 1995 and are projected to increase at a rate of 1.9% yr-1 in the next 25 years, if no improvement in emission control policy occurs. On a country-by-country basis, France is the leading emitter country with 22.6 t yr -1 followed by Turkey (16.1 t yr -1) , Italy (11.4 t yr -1) , Spain (9.1 t yr -1) , the former Yugoslavia 7.9 ( t yr -1) , Morocco (6.9 t yr -1) , Bulgaria (6.8 t yr -1) , Egypt (6.1 t yr -1) , Syria (3.6 t yr -1) , Libya (2.9 t yr -1) , Tunisia (2.8 t yr -1) and Greece (2.7 t yr -1) , whereas the remaining countries account for less than 7% of the regional total. The annual emission from natural sources is 110 t yr -1, although this figure only includes the volatilisation of elemental mercury from surface waters and emissions from volcanoes, whereas the contribution due to the degassing of mercury from top soil and vegetation has not been included in this first assessment. Therefore, natural and anthropogenic sources in the Mediterranean region release annually about 215 t of mercury, which represents a significant contribution to the total mercury budget released in Europe and to the global atmosphere.

  11. Anthropogenic effects on the subsurface thermal and groundwater environments in Osaka, Japan and Bangkok, Thailand.

    Science.gov (United States)

    Taniguchi, Makoto; Shimada, Jun; Fukuda, Yoichi; Yamano, Makoto; Onodera, Shin-ichi; Kaneko, Shinji; Yoshikoshi, Akihisa

    2009-04-15

    Anthropogenic effects in both Osaka and Bangkok were evaluated to compare the relationships between subsurface environment and the development stage of both cities. Subsurface thermal anomalies due to heat island effects were found in both cities. The Surface Warming Index (SWI), the departure depth from the steady geothermal gradient, was used as an indicator of the heat island effect. SWI increases (deeper) with the magnitude of heat island effect and the elapsed time starting from the surface warming. Distributions of subsurface thermal anomalies due to the heat island effect agreed well with the distribution of changes in air temperature due to the same process, which is described by the distribution of population density in both Osaka and Bangkok. Different time lags between groundwater depression and subsidence in the two cities was found. This is attributed to differences in hydrogeologic characters, such as porosity and hydraulic conductivity. We find that differences in subsurface degradations in Osaka and Bangkok, including subsurface thermal anomalies, groundwater depression, and land subsidence, depends on the difference of the development stage of urbanization and hydrogeological characters. PMID:18790519

  12. Distribution of anthropogenic radionuclides in the Moroccan marine environment

    International Nuclear Information System (INIS)

    Morocco has a long coast of 3500 km of which 500 km are on the south Mediterranean sea where little information on artificial radionuclides concentrations is available. There is no existing data in the Atlantic Ocean coast. The aim of this study carried out within the regional Project RAF7 held in co-operation with IAEA is the exploration of levels of radionuclides concentrations in the Moroccan marine environment with special emphasis on the anthropogenic radioactive contaminants; 137Cs, 239,240Pu and 241Am. In addition, concentration profiles of natural radionuclides as 210Pb and 226Ra in sediment were also determined allowing to estimate, through the excess Lead (210Pbex), the sedimentation rate and to reconstruct the history of contaminants. Samples were collected along 4 stations of which 3 are in the Mediterranean sea during a cruise aboard the oceanographic vessel Charif Al Idrissi of INRH. One station near 'Mdiq' (St.2) was extensively explored by collecting four samples of water at different depths until 900m and a bottom sediment core collected at a depth of 800 m using an Ocean Instrument Box corer. Sequential concentrations of radionuclides have been carried out on board by coprecipitating 239,240Pu and 241Am with MnO2 and the adsorption of 137Cs onto AMP. The sediment cores were sectioned into series of horizontal slices of 0.5 to 1 cm thickness to be analysed. 137Cs, 210Pb, 226Ra activities were measured by γ spectrometry using a CANBERRA HPGe detector with resolution of 2 keV and efficiency of 50%. For the α emitters as Pu and Am isotopes, a suitable radiochemical method was applied based on the separation of Pu from Am by anion -exchange resin AG1x8. Am was co-precipitated with calcium oxalate and extracted into DDCP and finally separated from rare earths by anion exchange in mineral acidsmethanol media. Both Pu and Am fraction are electrodeposited and the resulting alpha-sources are counted by ORTEC EG and G alpha spectrometry. The determination

  13. Ecohydrological evolution in the catchment of Lake Drūkšiai, Lithuania, under anthropogenic pressure

    OpenAIRE

    Mažeika, Jonas; Taminskas, Julius; Paškauskas, Ričardas; Bodoyan, Armen; Baghdassaryan, Hyke; Tozalakyan, Petros; Davtyan, Vahan; Grillot, Jean-Claude; Travi, Yves

    2006-01-01

    The catchment area of Lake Drūkšiai (the Ignalina Nuclear Power Plant cooling basin) is exposed to severe anthropogenic pressures due to urbanization, industrialization and, to a smaller scale, to agricultural development. Ecological changes in the lake are investigated in connection with the water balance of Lake Drūkšiai and the interaction of surface water and groundwater in the catchment. The main sources which contribute to the most active water exchange in the lake are total surface run...

  14. Global mercury emissions to the atmosphere from anthropogenic and natural sources

    OpenAIRE

    N. Pirrone; Cinnirella, S.; Feng, X.; Finkelman, R. B.; H. R. Friedli; Leaner, J.; Mason, R.; Mukherjee, A B; Stracher, G. B.; D. G. Streets; K. Telmer

    2010-01-01

    This paper provides an up-to-date assessment of global mercury emissions from anthropogenic and natural sources. On an annual basis, natural sources account for 5207 Mg of mercury released to the global atmosphere, including the contribution from re-emission processes, which are emissions of previously deposited mercury originating from anthropogenic and natural sources, and primary emissions from natural reservoirs. Anthropogenic sources, which include a large number of industrial poi...

  15. The climate influence of anthropogenic land-use changes on near-surface wind energy potential in China

    Institute of Scientific and Technical Information of China (English)

    LI Yan; WANG Yuan; CHU HuiYun; TANG JianPing

    2008-01-01

    There is considerable interest in the potential impact of climate change on wind energy in China. The climate change of near-surface wind energy potential in China under the background of global warming and its association with anthropogenic land-use changes are investigated by calculating the difference in surface wind speeds between the NCEP/NCAR reanalysis data and the observations since the re-analysis dataset contains the influence of large-scale climate changes due to greenhouse gases, it is less sensitive to regional surface processes associated with land types. The surface wind data in this study consist of long-tarm observations from 604 Chinese Roution Meteorological Stations and theNCEP/NCAR reanalysis data from 1960-1999. The results suggest that the observed mean wind speeds significantly weakened and the near-surface wind power trended downward due to urbanization and other land-use changes in the last 40 years. The mean wind energy weakened by -3.84 W·m-2 per decade due to the influence of anthropogenic land-use change, which is close to the observed climate change (-4.51 W·m-2/10 a).

  16. Enhanced CD3+/CD4+T Cell Activities and Modulation of Th1/Th2 Lineage Development in Irradiated Rats Due to Treatment with the Male Zooid of Antheraea Pernyi Extracts

    Institute of Scientific and Technical Information of China (English)

    ZHAO Bin; ZHANG Hong-Yu; ZHAO Wen-Hua; ZHANG Bo; ZONG Min; TANG Ji-dong; YU Jin-ming; LI Sheng

    2008-01-01

    Objective:Cancer patients undergoing large dose radiotherapy exhibit multifaceted defects in their immune capacity that are likely to contribute to an increased susceptibility to infections and disease progression.The immune impairment may also constitute a barrier to effective immunotherapeutic interventions.Here.we evaluate whether supplementation with the male zooid of Antheraea pernyi extracts could enhance immune function in irradiated rats. Methods:Fifty male Wistar rats were randomly divided into a control group,a simple radiation group and a treatment group.The mice in the simple irradiation and treatment groups were given whole-chest irradiation with 6Gy.In the treatment group,the male zooid of Antheraea pernyi extracts was gavaged at the doses of 16.53mg/kg(1arge dose group),2.62mg/kg(medium dose group),and 0.564mg/kg(small dose group)once a day for 14 days.The thymus and spleen indices were calculated.T cell subsets in peripheral blood were determined by flow cytometry and the expressions of IL-2,IFN-γ,IL-4 and IL-10 in sera were determined by ELISA on the 15th day. Results:The thymus index and spleen index of the high dose treatment group were statistically lower than that of the control group and higher than that of the radiation group(P<0.01).CD3+and CD4+ T cells in the peripheral blood were increased in the high dose treatment group and decreased in the radiation group(P<0.01).Expression of IL-2 and INF-γ in the radiation group was lower than that in control,and significantly increased during therapy.The production of IL-4 and IL-10 could be induced by radiation and was inhibited in the high dose treatment group(P<0.01). Conclusion:Our data indicate that the male zooid of Antheraea pernyi extracts may be administrated to improve immune function in irradiated rats and reverse the radial immune inhibition of rats by stimulating the proliferation of Th cells and inducing the differentiation of Th2 to Th1.

  17. Geomorphological Responses to Anthropogenic Alterations within the Nakdong and Yeongsan Estuaries, South Korea

    Science.gov (United States)

    Williams, Joshua; Dellapenna, Timothy; Lee, guan-hong

    2016-04-01

    On the Korean Peninsula, significant anthropogenic alterations have occurred to drainage basins and estuaries due to river diversion for agricultural practices, coastal construction of estuarine barrages, and extensive seawalls in land reclamation projects. Over the past century these practices have considerably modified the shoreline and altered both net transport of sediment and freshwater from these systems and modulated the timing and intensity of the discharge. As a result, the sediment dynamics and ecosystems within the estuaries have been significantly altered. Considering drainage basins >500 km2, 56% of rivers reaching the coast in South Korea have been occluded by an estuarine dam, restricting delivery of sediments and altering/preventing natural tidal exchange of fresh and saltwater. The Nakdong and Yeongsan Estuaries are prime examples and are respectively representative of micro and macro-tidal estuaries found in the region. The impacts of the modifications include a substantial decrease in the tidal prism, reduction of accommodation space in intertidal zones, and changes in the dispersal mechanisms and accumulation of sediments. In order to assess these alterations, a series of gravity and vibracores were analyzed using 210Pb and 137Cs radioisotope geochronology, laser diffraction particle analyses, and X-radiography. Additionally, side scan sonar and CHIRP seismic data were collected. Our observations have found a shift in depositional environments as a natural response to an extensive array of anthropogenic alterations. The changes in sediment trapping efficiency that have ensued resulting from extensive coastal construction provides the basis for reevaluating traditional facies models for estuaries in the Anthropocene

  18. Self-cleaning in an estuarine area formerly affected by 226Ra anthropogenic enhancements. Numerical simulations

    International Nuclear Information System (INIS)

    A numerical model of the Odiel-Tinto estuary (Spain) has been developed to study the self-cleaning process that was evidenced from 226Ra measurements in water and sediments collected in the period 1999-2002, after direct releases from a fertilizer complex ceased (in 1998). The hydrodynamic model is first calibrated, and standard tidal analysis is carried out to calculate tidal constants required by the dispersion code to determine instantaneous water currents and elevations over the estuary. In this way, long-term simulations may be carried out. The dispersion code includes advective/diffusive transport of radionuclides plus exchanges with bottom sediments described through a kinetic approach. The dispersion model is first tested by comparing computed and measured 226Ra concentrations over the estuary resulting after releases in the Odiel and Tinto rivers. Next, it is applied to simulate the self-cleaning process of the estuary. The time evolution of radium concentrations in bed sediments is in generally good agreement with observations. The computed sediment halving time of the estuary is 510 days, which also is in good agreement with that estimated from measurements

  19. National greenhouse gas accounts: Current anthropogenic sources and sinks

    International Nuclear Information System (INIS)

    This study provides spatially disaggregated estimates of greenhouse gas emissions from the major anthropogenic sources for 145 countries. The data compilation is comprehensive in approach, including emissions from CO, CH4, N2O and ten halocarbons, in addition to CO2. The sources include emissions from fossil fuel production and use, cement production, halocarbons, landfills, land use changes, biomass burning, rice and livestock production and fertilizer consumption. The approach used to derive these estimates corresponds closely with the simple methodologies proposed by the Greenhouse Gas Emissions Task Force of the Intergovernmental Panel on Climate Change. The inventory includes a new estimate of greenhouse gas emissions from fossil fuel combustion based principally on data from the International Energy Agency. The research methodologies for estimating emissions from all sources is briefly described and compared with other recent studies in the literature. (112 refs.)

  20. Aspects of anthropogenic influence in Piracicaba (SP river dissolved load

    Directory of Open Access Journals (Sweden)

    Diego Vendramini

    2013-09-01

    Full Text Available The anthropogenic influence in Piracicaba river dissolved load were studied for major inorganic chemical species and characterized in terms of total loads. The concentration distribution curves, in function of time, were compared with respective theoretical dilution, what allowed the identification of punctual and diffuse contributions in the drainage basin. The dissolved chemical loads transported in these surface waters were calculated by stochastic method, and they were more significant for HCO3-, Na+and SO42-. Nitrogen species (NH4+ and NO3- were the most significant rainwater contribution. The punctual contributions were mainly associated to raw urban sewage released without treatment, considering Na+, Cl-, PO43-, SO42- and part of HCO3- species. The diffuse contributions were related to rainwater, soil cultivation and rocks weathering contributions.

  1. Phosphorus in Denmark: national and regional anthropogenic flows

    DEFF Research Database (Denmark)

    Klinglmair, Manfred; Lemming, Camilla; Jensen, Lars Stoumann;

    2015-01-01

    areas around the eastern urban agglomerations, from more complete recovery of sewage sludge (with unrecovered P amounts of up to 33% of P in current mineral fertiliser imports) and the biowaste fraction in municipal solid waste currently not collected separately (24% of P in current mineral fertiliser...... by country-wide average values. To quantify and evaluate these imbalances we integrated a country-scale and regional-scale model of the Danish anthropogenic P flows and stocks. We examine three spatial regions with regard to agriculture, as the main driver for P use, and waste management, the crucial...... to transport limitations. Second, waste management, closely linked to population and industrial density is the driver behind differences in recoverable P flows. Current amounts of potentially recoverable P cannot change the reliance on primary P. The most immediate P re-use potential exists in the...

  2. Anthropogenic climate change impacts on ponds: a thermal mass perspective

    Directory of Open Access Journals (Sweden)

    John Matthews

    2010-12-01

    Full Text Available Small freshwater aquatic lentic systems (lakes and ponds are sensitive to anthropogenic climate change through shifts in ambient air temperatures and patterns of precipitation. Shifts in air temperatures will influence lentic water temperatures through convection and by changing evaporation rates. Shifts in the timing, amount, and intensity of precipitation will alter the thermal mass of lentic systems even in the absence of detectable ambient air temperature changes. These effects are likely to be strongest in ponds (standing water bodies primarily mixed by temperature changes than by wind, for whom precipitation makes up a large component of inflows. Although historical water temperature datasets are patchy for lentic systems, thermal mass effects are likely to outweigh impacts from ambient air temperatures in most locations and may show considerable independence from those trends. Thermal mass-induced changes in water temperature will thereby alter a variety of population- and community-level processes in aquatic macroinvertebrates.

  3. Psychic pathology o