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Sample records for allen fossil plant

  1. Adaptation, plant evolution, and the fossil record

    NASA Technical Reports Server (NTRS)

    Knoll, A. H.; Niklas, K. J.

    1987-01-01

    The importance of adaptation in determining patterns of evolution has become an important focus of debate in evolutionary biology. As it pertains to paleobotany, the issue is whether or not adaptive evolution mediated by natural selection is sufficient to explain the stratigraphic distributions of taxa and character states observed in the plant fossil record. One means of addressing this question is the functional evaluation of stratigraphic series of plant organs set in the context of paleoenvironmental change and temporal patterns of floral composition within environments. For certain organ systems, quantitative estimates of biophysical performance can be made on the basis of structures preserved in the fossil record. Performance estimates for plants separated in time or space can be compared directly. Implicit in different hypotheses of the forces that shape the evolutionary record (e.g. adaptation, mass extinction, rapid environmental change, chance) are predictions about stratigraphic and paleoenvironmental trends in the efficacy of functional performance. Existing data suggest that following the evolution of a significant structural innovation, adaptation for improved functional performance can be a major determinant of evolutionary changes in plants; however, there are structural and development limits to functional improvement, and once these are reached, the structure in question may no longer figure strongly in selection until and unless a new innovation evolves. The Silurian-Devonian paleobotanical record is consistent with the hypothesis that the succession of lowland floodplain dominants preserved in the fossil record of this interval was determined principally by the repeated evolution of new taxa that rose to ecological importance because of competitive advantages conferred by improved biophysical performance. This does not seem to be equally true for Carboniferous-Jurassic dominants of swamp and lowland floodplain environments. In these cases

  2. Adaptation, plant evolution, and the fossil record.

    PubMed

    Knoll, A H; Niklas, K J

    1987-01-01

    The importance of adaptation in determining patterns of evolution has become an important focus of debate in evolutionary biology. As it pertains to paleobotany, the issue is whether or not adaptive evolution mediated by natural selection is sufficient to explain the stratigraphic distributions of taxa and character states observed in the plant fossil record. One means of addressing this question is the functional evaluation of stratigraphic series of plant organs set in the context of paleoenvironmental change and temporal patterns of floral composition within environments. For certain organ systems, quantitative estimates of biophysical performance can be made on the basis of structures preserved in the fossil record. Performance estimates for plants separated in time or space can be compared directly. Implicit in different hypotheses of the forces that shape the evolutionary record (e.g. adaptation, mass extinction, rapid environmental change, chance) are predictions about stratigraphic and paleoenvironmental trends in the efficacy of functional performance. Existing data suggest that following the evolution of a significant structural innovation, adaptation for improved functional performance can be a major determinant of evolutionary changes in plants; however, there are structural and development limits to functional improvement, and once these are reached, the structure in question may no longer figure strongly in selection until and unless a new innovation evolves. The Silurian-Devonian paleobotanical record is consistent with the hypothesis that the succession of lowland floodplain dominants preserved in the fossil record of this interval was determined principally by the repeated evolution of new taxa that rose to ecological importance because of competitive advantages conferred by improved biophysical performance. This does not seem to be equally true for Carboniferous-Jurassic dominants of swamp and lowland floodplain environments. In these cases

  3. Atmospheric CO2 from fossil plant cuticles.

    PubMed

    Kerp, Hans

    2002-01-03

    Plants respond to changes in atmospheric carbon dioxide levels by regulating the number of stomata in their leaves. In his reconstruction of a continuous, 300-million-year record of atmospheric CO2, Retallack bases his curve on stomatal counts of fossil plant cuticles taken from published micrographs. However, the preservation of cuticles from Permian times is generally too fragmentary for the stomatal index to be reliably determined, the micrographs used could have biased the results, and there are important errors in the supplementary data - all of which cast doubt on the Permian part of Retallack's record.

  4. Modeling of advanced fossil fuel power plants

    NASA Astrophysics Data System (ADS)

    Zabihian, Farshid

    The first part of this thesis deals with greenhouse gas (GHG) emissions from fossil fuel-fired power stations. The GHG emission estimation from fossil fuel power generation industry signifies that emissions from this industry can be significantly reduced by fuel switching and adaption of advanced power generation technologies. In the second part of the thesis, steady-state models of some of the advanced fossil fuel power generation technologies are presented. The impacts of various parameters on the solid oxide fuel cell (SOFC) overpotentials and outputs are investigated. The detail analyses of operation of the hybrid SOFC-gas turbine (GT) cycle when fuelled with methane and syngas demonstrate that the efficiencies of the cycles with and without anode exhaust recirculation are close, but the specific power of the former is much higher. The parametric analysis of the performance of the hybrid SOFC-GT cycle indicates that increasing the system operating pressure and SOFC operating temperature and fuel utilization factor improves cycle efficiency, but the effects of the increasing SOFC current density and turbine inlet temperature are not favourable. The analysis of the operation of the system when fuelled with a wide range of fuel types demonstrates that the hybrid SOFC-GT cycle efficiency can be between 59% and 75%, depending on the inlet fuel type. Then, the system performance is investigated when methane as a reference fuel is replaced with various species that can be found in the fuel, i.e., H2, CO2, CO, and N 2. The results point out that influence of various species can be significant and different for each case. The experimental and numerical analyses of a biodiesel fuelled micro gas turbine indicate that fuel switching from petrodiesel to biodiesel can influence operational parameters of the system. The modeling results of gas turbine-based power plants signify that relatively simple models can predict plant performance with acceptable accuracy. The unique

  5. Evaluation of effects of groundwater withdrawals at the proposed Allen combined-cycle combustion turbine plant, Shelby County, Tennessee

    USGS Publications Warehouse

    Haugh, Connor J.

    2016-08-10

    The Mississippi Embayment Regional Aquifer Study groundwater-flow model was used to simulate the potential effects of future groundwater withdrawals at the proposed Allen combined-cycle combustion turbine plant in Shelby County, Tennessee. The scenario used in the simulation consisted of a 30-year average withdrawal period followed by a 30-day maximum withdrawal period. Effects of withdrawals at the Allen plant site on the Mississippi embayment aquifer system were evaluated by comparing the difference in simulated water levels in the aquifers at the end of the 30-year average withdrawal period and at the end of the scenario to a base case without the Allen combined-cycle combustion turbine plant withdrawals. Simulated potentiometric surface declines in the Memphis aquifer at the Allen plant site were about 7 feet at the end of the 30-year average withdrawal period and 11 feet at the end of the scenario. The affected area of the Memphis aquifer at the Allen plant site as delineated by the 4-foot potentiometric surface-decline contour was 2,590 acres at the end of the 30-year average withdrawal period and 11,380 acres at the end of the scenario. Simulated declines in the underlying Fort Pillow aquifer and overlying shallow aquifer were both less than 1 foot at the end of the 30-year average withdrawal period and the end of the scenario.

  6. Evaluation of fossil plants versus hydro plants for load frequency control

    SciTech Connect

    Broadwater, R.P.; Johnson, R.L.; Duckett, F.E.; Boston, W.T.

    1985-01-01

    The economics of using hydroplants with Francis turbines or fossil plants for load frequency control are evaluated. Using data from the TVA Gallatin steam plant and the TVA Cherokee, Wilson, and Fontana hydroplants, a cost comparison of different modes of operation for load frequency control was performed considering two plants at a time. The results showed that when the fossil plant was used for load frequency control instead of a hydro plant a lower system generation cost was incurred. Dynamic responses of fossil and hydro units, improved controls for fossil plants, and maneuvering costs of the Gallatin plant are also considered.

  7. Zeolites replacing plant fossils in the Denver formation, Lakewood, Colorado.

    USGS Publications Warehouse

    Modreski, P.J.; Verbeek, E.R.; Grout, M.A.

    1984-01-01

    Well-developed crystals of heulandite and stilbite, within fossil wood, occur in sedimentary rocks in Lakewood, Jefferson County. The rocks belong to the Denver formation, a locally fossiliferous deposit of fluvial claystone, siltstone, sandstone and conglomerate, containing some volcanic mudflows (andesitic) of late Cretaceous to Palaeocene age. Altered volcanic glass released Na and Ca into the ground-water and subsequently zeolites were crystallized in the open spaces between grains and within fossil plant structures. Minor pyrite, quartz (jasper), calcite and apatite also occur as replacements of fossil wood. Similar zeolite occurrences in other areas are reviewed.-R.S.M.

  8. Case studies on recent fossil-fired plants

    SciTech Connect

    Henderson, C.

    2007-12-31

    The article summarises the findings of case studies on fossil-fired power plants carried out by the IEA Clean Coal Centre for the IEA at the request of world leaders at the Gleneagles G8 Summit in July 2005. The studies compared the cost, efficiency and emissions of eight recently constructed coal-fired plants using pulverized coal combustion with subcritical, supercritical or ultra-supercritical steam turbine cycles. Also included was a review of IGCC developments. A case study of a natural gas combined-cycle plant was included for comparison. The full report has been published by the IEA. 1 tab.

  9. Advanced fission and fossil plant economics-implications for fusion

    SciTech Connect

    Delene, J.G.

    1994-09-01

    In order for fusion energy to be a viable option for electric power generation, it must either directly compete with future alternatives or serve as a reasonable backup if the alternatives become unacceptable. This paper discusses projected costs for the most likely competitors with fusion power for baseload electric capacity and what these costs imply for fusion economics. The competitors examined include advanced nuclear fission and advanced fossil-fired plants. The projected costs and their basis are discussed. The estimates for these technologies are compared with cost estimates for magnetic and inertial confinement fusion plants. The conclusion of the analysis is that fusion faces formidable economic competition. Although the cost level for fusion appears greater than that for fission or fossil, the costs are not so high as to preclude fusion`s potential competitiveness.

  10. HIGH EFFICIENCY FOSSIL POWER PLANT (HEFPP) CONCEPTUALIZATION PROGRAM

    SciTech Connect

    J.L. Justice

    1999-03-25

    This study confirms the feasibility of a natural gas fueled, 20 MW M-C Power integrated pressurized molten carbonate fuel cell combined in a topping cycle with a gas turbine generator plant. The high efficiency fossil power plant (HEFPP) concept has a 70% efficiency on a LHV basis. The study confirms the HEFPP has a cost advantage on a cost of electricity basis over the gas turbine based combined cycle plants in the 20 MW size range. The study also identifies the areas of further development required for the fuel cell, gas turbine generator, cathode blower, inverter, and power module vessel. The HEFPP concept offers an environmentally friendly power plant with minuscule emission levels when compared with the combined cycle power plant.

  11. Maintaining hydrothermal compliance at TVA's nuclear and fossil plants

    SciTech Connect

    Hopping, P.; Montgomery, C.; Shiao, M.; Bodine, D.

    1998-07-01

    The Tennessee Valley Authority (TVA) currently operates three nuclear plants and eleven fossil plants, all of which rely on nearby rivers to dissipate waste heat. To avoid permit violations of the National Pollutant Discharge Elimination System (NPDES), TVA is required to curtail generation at a given facility if the temperature of the plant discharge exceeds allowable limits. To minimize the threat of NPDES violations and, consequently, reduce generation losses, TVA has developed a number of innovative techniques to monitor, forecast, optimize, and control instream water temperature. This paper highlights those for the Widows Creek Fossil Plant. The Widows Creek Fossil Plant (WCF) is located on the northern shore of the Tennessee River, 58.9 miles upstream of Guntersville Dam and 17.2 miles downstream of Nickajack Dam. Hydroplants located at the upstream and downstream dams are operated in the summer to provide generation solely for peaking. This operation, however, creates reverse flow in the river causing heated water from the WCF discharge to migrate upstream and enter the plant intake. This recirculation occurs within several hours after cessation of operations at the upstream and downstream hydroplants. To avoid NPDES temperature violations, generation curtailment occasionally is necessary at WCF during these events. For example, in August 1995, excess water temperatures caused a loss of about 230 unit-hours of generation, valued at over $250,000. To minimize reverse flow at WCG, alternative generation schedules were simulated for the upstream and downstream hydroplants. This was accomplished using a water quality model. The results show that the hydro releases could be effectively altered to reduce the peak water temperature, and consequently, the amount of generation curtailment at WCF. In all cases, however, modifying the hydroplant schedule reduces the available capacity to provide peaking.

  12. Chemical signatures of fossilized resins and recent plant exudates.

    PubMed

    Lambert, Joseph B; Santiago-Blay, Jorge A; Anderson, Ken B

    2008-01-01

    Amber is one of the few gemstones based on an organic structure. Found over most of the world, it is the fossil form of sticky plant exudates called resins. Investigation of amber by modern analytical techniques provides structural information and insight into the identity of the ancient plants that produced the source resin. Mass spectrometric analysis of materials separated by gas chromatography has identified specific compounds that are the basis of a reliable classification of the different types of amber. NMR spectroscopy of bulk, solid amber provides a complementary classification. NMR spectroscopy also can be used to characterize modern resins as well as other types of plant exudates such as gums, gum resins, and kinos, which strongly resemble resins in appearance but have very different molecular constitutions.

  13. Hydrogen Separation Membranes for Vision 21 Fossil Fuel Plants

    SciTech Connect

    Roark, Shane E.; Mackay, Richard; Sammells, Anthony F.

    2001-11-06

    Eltron Research and team members CoorsTek, McDermott Technology, Sued Chemie, Argonne National Laboratory, and Oak Ridge National Laboratory are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. This project was motivated by the Department of Energy (DOE) National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. The proposed technology addresses the DOE Vision 21 initiative in two ways. First, this process offers a relatively inexpensive solution for pure hydrogen separation that can be easily incorporated into Vision 21 fossil fuel plants. Second, this process could reduce the cost of hydrogen, which is a clean burning fuel under increasing demand as supporting technologies are developed for hydrogen utilization and storage. Additional motivation for this project arises from the potential of this technology for other applications. By appropriately changing the catalysts coupled with the membrane, essentially the same system can be used to facilitate alkane dehydrogenation and coupling, aromatics processing, and hydrogen sulfide decomposition.

  14. [Lipids from fossil plants and their relation to modern plants. Example s of Cenomanian flora from Anjou and Bohemia].

    PubMed

    Thanh, T N; Derenne, S; Largeau, C; Pons, D; Broutin, J; Mariotti, A; Bocherens, H

    2000-01-01

    Comparative analyses of lipids from fossil plants and from their extant counterparts were undertaken in order to test the taxonomic significance of lipids in palaeobotany. The comparison between lipids from a fossil Ginkgoaceae, Eretmophyllum andegavense, and its extant counterpart, Ginkgo biloba, revealed the presence of original molecules, dimethoxyalkylcoumarins, in lipids from both plants. Such compounds confirm, on chemical grounds the relationship between these extant and fossil Ginkgoaceaes. Moreover, differences in n-alkane distribution between E. andegavense and E. obtusum which are very similar morphologically, confirm that these fossil plants do not belong to the same species. Furthermore, comparative analyses of a fossil Cheirolepidiaceae, Frenelopsis alata, and its extant counterpart, the Cupressaceae Tetraclinis articulata, revealed some similarities between these two species although they do not belong to the same family. Otherwise, comparative analyses of fungi-infected and uninfected samples of F. alata demonstrated that these micro-organisms can significantly affect the chemical composition of fossil plant lipids. In conclusion, even if chemical analyses alone are not sufficient to determine the genus or species of a given fossil plant, they can precise the taxonomy of some specimens that have been previously studied by palaeobotanists.

  15. Noise control at fossil fuel power plants: an industrywide assessment of costs and benefits. Final report

    SciTech Connect

    Hoover, R.M.

    1983-12-01

    This report presents the results of a study on the costs and perceived benefits of noise control measures currently installed at fossil power plants. Information for this study was sought from the entire fossil power plant industry in this country through a questionnaire survey and through discussions with utility personnel. A total of 84 power companies responded with information on plants. In addition, five power plants with extensive noise control measures were selected for detailed study. For these plants, case histories were prepared following plant visits and discussions with utility personnel regarding the specific noise control measures. Based on these case histories and the results of the questionnaire survey, noise control costs and perceived benefits are presented for major power plant equipment categories including draft fans, boiler feed pumps, turbine-generator systems, valves, and transformers. 12 references, 14 figures, 7 tables.

  16. Fossil organic carbon in wastewater and its fate in treatment plants.

    PubMed

    Law, Yingyu; Jacobsen, Geraldine E; Smith, Andrew M; Yuan, Zhiguo; Lant, Paul

    2013-09-15

    This study reports the presence of fossil organic carbon in wastewater and its fate in wastewater treatment plants. The findings pinpoint the inaccuracy of current greenhouse gas accounting guidelines which defines all organic carbon in wastewater to be of biogenic origin. Stable and radiocarbon isotopes ((13)C and (14)C) were measured throughout the process train in four municipal wastewater treatment plants equipped with secondary activated sludge treatment. Isotopic mass balance analyses indicate that 4-14% of influent total organic carbon (TOC) is of fossil origin with concentrations between 6 and 35 mg/L; 88-98% of this is removed from the wastewater. The TOC mass balance analysis suggests that 39-65% of the fossil organic carbon from the influent is incorporated into the activated sludge through adsorption or from cell assimilation while 29-50% is likely transformed to carbon dioxide (CO2) during secondary treatment. The fossil organic carbon fraction in the sludge undergoes further biodegradation during anaerobic digestion with a 12% decrease in mass. 1.4-6.3% of the influent TOC consists of both biogenic and fossil carbon is estimated to be emitted as fossil CO2 from activated sludge treatment alone. The results suggest that current greenhouse gas accounting guidelines, which assume that all CO2 emission from wastewater is biogenic may lead to underestimation of emissions.

  17. Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants

    SciTech Connect

    Carl R. Evenson; Richard N. Kleiner; James E. Stephan; Frank E. Anderson

    2006-04-30

    Eltron Research Inc. and team members CoorsTek, Sued Chemie, Argonne National Laboratory, and NORAM are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative, which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. Currently, this project is focusing on four basic categories of dense membranes: (1) mixed conducting ceramic/ceramic composites, (2) mixed conducting ceramic/metal (cermet) composites, (3) cermets with hydrogen permeable metals, and (4) layered composites containing hydrogen permeable alloys. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this final quarter of the no cost extension several planar membranes of a cermet composition referred to as EC101 containing a high permeability metal and a ceramic phase were prepared and permeability testing was performed.

  18. Atmospheric benzenoid emissions from plants rival those from fossil fuels

    PubMed Central

    Misztal, P.K.; Hewitt, C.N.; Wildt, J.; Blande, J.D.; Eller, A.S.D.; Fares, S.; Gentner, D.R.; Gilman, J.B.; Graus, M.; Greenberg, J.; Guenther, A.B.; Hansel, A.; Harley, P.; Huang, M.; Jardine, K.; Karl, T.; Kaser, L.; Keutsch, F.N.; Kiendler-Scharr, A.; Kleist, E.; Lerner, B.M.; Li, T.; Mak, J.; Nölscher, A.C.; Schnitzhofer, R.; Sinha, V.; Thornton, B.; Warneke, C.; Wegener, F.; Werner, C.; Williams, J.; Worton, D.R.; Yassaa, N.; Goldstein, A.H.

    2015-01-01

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y−1), pointing to the importance of these natural emissions in atmospheric physics and chemistry. PMID:26165168

  19. Atmospheric benzenoid emissions from plants rival those from fossil fuels.

    PubMed

    Misztal, P K; Hewitt, C N; Wildt, J; Blande, J D; Eller, A S D; Fares, S; Gentner, D R; Gilman, J B; Graus, M; Greenberg, J; Guenther, A B; Hansel, A; Harley, P; Huang, M; Jardine, K; Karl, T; Kaser, L; Keutsch, F N; Kiendler-Scharr, A; Kleist, E; Lerner, B M; Li, T; Mak, J; Nölscher, A C; Schnitzhofer, R; Sinha, V; Thornton, B; Warneke, C; Wegener, F; Werner, C; Williams, J; Worton, D R; Yassaa, N; Goldstein, A H

    2015-07-13

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y(-1)), pointing to the importance of these natural emissions in atmospheric physics and chemistry.

  20. Mass extinction events and the plant fossil record.

    PubMed

    McElwain, Jennifer C; Punyasena, Surangi W

    2007-10-01

    Five mass extinction events have punctuated the geological record of marine invertebrate life. They are characterized by faunal extinction rates and magnitudes that far exceed those observed elsewhere in the geological record. Despite compelling evidence that these extinction events were probably driven by dramatic global environmental change, they were originally thought to have little macroecological or evolutionary consequence for terrestrial plants. New high-resolution regional palaeoecological studies are beginning to challenge this orthodoxy, providing evidence for extensive ecological upheaval, high species-level turnover and recovery intervals lasting millions of years. The challenge ahead is to establish the geographical extent of the ecological upheaval, because reconstructing the vegetation dynamics associated with these events will elucidate the role of floral change in faunal mass extinction and provide a better understanding of how plants have historically responded to global environmental change similar to that anticipated for our future.

  1. The Fossil Record of Plant-Insect Dynamics

    NASA Astrophysics Data System (ADS)

    Labandeira, Conrad C.; Currano, Ellen D.

    2013-05-01

    Progress toward understanding the dynamics of ancient plant-insect associations has addressed major patterns in the ecology and evolution of herbivory and pollination. This advancement involves development of more analytical ways of describing plant-insect associational patterns in time and space and an assessment of the role that the environment and internal biological processes have in their control. Current issues include the deep origins of terrestrial herbivory, the spread of herbivory across late Paleozoic landscapes, recoveries from sudden major crises, reaction to and accommodation of protracted environmental perturbations, and the nature of herbivory and pollination before the appearance of angiosperms during the mid-Mesozoic. These and other exploratory research themes provide a more complete account of a great nexus of ecological activity that has been wedged between the two most diverse organismic groups on land for the past 410 million years.

  2. Atmospheric benzenoid emissions from plants rival those from fossil fuels

    SciTech Connect

    Misztal, P. K.; Hewitt, C. N.; Wildt, J.; Blande, J. D.; Eller, A. S.D.; Fares, S.; Gentner, D. R.; Gilman, J. B.; Graus, M.; Greenberg, J.; Guenther, A. B.; Hansel, A.; Harley, P.; Huang, M.; Jardine, K.; Karl, T.; Kaser, L.; Keutsch, F. N.; Kiendler-Scharr, A.; Kleist, E.; Lerner, B. M.; Li, T.; Mak, J.; Nölscher, A. C.; Schnitzhofer, R.; Sinha, V.; Thornton, B.; Warneke, C.; Wegener, F.; Werner, C.; Williams, J.; Worton, D. R.; Yassaa, N.; Goldstein, A. H.

    2015-07-13

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y-1), pointing to the importance of these natural emissions in atmospheric physics and chemistry.

  3. Atmospheric benzenoid emissions from plants rival those from fossil fuels

    DOE PAGES

    Misztal, P. K.; Hewitt, C. N.; Wildt, J.; ...

    2015-07-13

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functionsmore » of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y-1), pointing to the importance of these natural emissions in atmospheric physics and chemistry.« less

  4. Atmospheric benzenoid emissions from plants rival those from fossil fuels

    NASA Astrophysics Data System (ADS)

    Misztal, P. K.; Hewitt, C. N.; Wildt, J.; Blande, J. D.; Eller, A. S. D.; Fares, S.; Gentner, D. R.; Gilman, J. B.; Graus, M.; Greenberg, J.; Guenther, A. B.; Hansel, A.; Harley, P.; Huang, M.; Jardine, K.; Karl, T.; Kaser, L.; Keutsch, F. N.; Kiendler-Scharr, A.; Kleist, E.; Lerner, B. M.; Li, T.; Mak, J.; Nölscher, A. C.; Schnitzhofer, R.; Sinha, V.; Thornton, B.; Warneke, C.; Wegener, F.; Werner, C.; Williams, J.; Worton, D. R.; Yassaa, N.; Goldstein, A. H.

    2015-07-01

    Despite the known biochemical production of a range of aromatic compounds by plants and the presence of benzenoids in floral scents, the emissions of only a few benzenoid compounds have been reported from the biosphere to the atmosphere. Here, using evidence from measurements at aircraft, ecosystem, tree, branch and leaf scales, with complementary isotopic labeling experiments, we show that vegetation (leaves, flowers, and phytoplankton) emits a wide variety of benzenoid compounds to the atmosphere at substantial rates. Controlled environment experiments show that plants are able to alter their metabolism to produce and release many benzenoids under stress conditions. The functions of these compounds remain unclear but may be related to chemical communication and protection against stress. We estimate the total global secondary organic aerosol potential from biogenic benzenoids to be similar to that from anthropogenic benzenoids (~10 Tg y-1), pointing to the importance of these natural emissions in atmospheric physics and chemistry.

  5. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Mohamed Darwish; Diego Acevedo; Jessica Knight

    2003-09-01

    This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system, which is powered by the waste heat from low pressure condensing steam in power plants. The desalination is driven by water vapor saturating dry air flowing through a diffusion tower. Liquid water is condensed out of the air/vapor mixture in a direct contact condenser. A thermodynamic analysis demonstrates that the DDD process can yield a fresh water production efficiency of 4.5% based on a feed water inlet temperature of only 50 C. An example is discussed in which the DDD process utilizes waste heat from a 100 MW steam power plant to produce 1.51 million gallons of fresh water per day. The main focus of the initial development of the desalination process has been on the diffusion tower. A detailed mathematical model for the diffusion tower has been described, and its numerical implementation has been used to characterize its performance and provide guidance for design. The analysis has been used to design a laboratory scale diffusion tower, which has been thoroughly instrumented to allow detailed measurements of heat and mass transfer coefficient, as well as fresh water production efficiency. The experimental facility has been described in detail.

  6. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight

    2004-09-01

    An innovative Diffusion Driven Desalination (DDD) process was recently described where evaporation of mineralized water is driven by diffusion within a packed bed. The energy source to drive the process is derived from low pressure condensing steam within the main condenser of a steam power generating plant. Since waste heat is used to drive the process, the main cost of fresh water production is attributed to the energy cost of pumping air and water through the packed bed. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A combined thermodynamic and dynamic analysis demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3'' Hg. Throughout the past year, the main focus of the desalination process has been on the diffusion tower and direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. An experimental DDD facility has been fabricated, and temperature and humidity data have been collected over a range of flow and thermal conditions. The analyses agree quite well with the current data and the information available in the literature. Direct contact condensers with and without packing have been investigated. It has been experimentally observed that the fresh water production rate is significantly enhanced when packing is added to the direct contact condensers.

  7. Innovative Fresh Water Production Process for Fossil Fuel Plants

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight; Venugopal Jogi

    2005-09-01

    This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A dynamic analysis of heat and mass transfer demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3 Hg. The optimum operating condition for the DDD process with a high temperature of 50 C and sink temperature of 25 C has an air mass flux of 1.5 kg/m{sup 2}-s, air to feed water mass flow ratio of 1 in the diffusion tower, and a fresh water to air mass flow ratio of 2 in the condenser. Operating at these conditions yields a fresh water production efficiency (m{sub fW}/m{sub L}) of 0.031 and electric energy consumption rate of 0.0023 kW-hr/kg{sub fW}. Throughout the past year, the main focus of the desalination process has been on the direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. The analyses agree quite well with the current data. Recently, it has been recognized that the fresh water production efficiency can be significantly enhanced with air heating. This type of configuration is well suited for power plants utilizing air-cooled condensers. The experimental DDD facility has been modified with an air heating section, and temperature and humidity data have been collected over a range of flow and thermal conditions. It has been experimentally observed that the fresh water production rate is enhanced when air

  8. Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants

    SciTech Connect

    Carl R. Evenson; Shane E. Roark

    2006-03-31

    The objective of this project was to develop an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. A family of hydrogen separation membranes was developed including single phase mixed conducting ceramics, ceramic/ceramic composites, cermet membranes, cermet membranes containing a hydrogen permeable metal, and intermediate temperature composite layered membranes. Each membrane type had different operating parameters, advantages, and disadvantages that were documented over the course of the project. Research on these membranes progressed from ceramics to cermets to intermediate temperature composite layered membranes. During this progression performance was increased from 0.01 mL x min{sup -1} x cm{sup -2} up to 423 mL x min{sup -1} x cm{sup -2}. Eltron and team membranes not only developed each membrane type, but also membrane surface catalysis and impurity tolerance, creation of thin film membranes, alternative applications such as membrane promoted alkane dehydrogenation, demonstration of scale-up testing, and complete engineering documentation including process and mechanical considerations necessary for inclusion of Eltron membranes in a full scale integrated gasification combined cycle power plant. The results of this project directly led to a new $15 million program funded by the Department of Energy. This new project will focus exclusively on scale-up of this technology as part of the FutureGen initiative.

  9. Do fossil plants signal palaeoatmospheric carbon dioxide concentration in the geological past?

    PubMed Central

    McElwain, J. C.

    1998-01-01

    Fossil, subfossil, and herbarium leaves have been shown to provide a morphological signal of the atmospheric carbon dioxide environment in which they developed by means of their stomatal density and index. An inverse relationship between stomatal density/index and atmospheric carbon dioxide concentration has been documented for all the studies to date concerning fossil and subfossil material. Furthermore, this relationship has been demonstrated experimentally by growing plants under elevated and reducedcarbon dioxide concentrations. To date, the mechanism that controls the stomatal density response to atmospheric carbon dioxide concentration remains unknown. However, stomatal parameters of fossil plants have been successfully used as a proxy indicator of palaeo-carbon dioxide levels. This paper presents new estimates of palaeo-atmospheric carbon dioxide concentrations for the Middle Eocene (Lutetian), based on the stomatal ratios of fossil Lauraceae species from Bournemouth in England. Estimates of atmospheric carbon dioxide concentrations derived from stomatal data from plants of the Early Devonian, Late Carboniferous, Early Permian and Middle Jurassic ages are reviewed in the light of new data. Semi-quantitative palaeo-carbon dioxide estimates based on the stomatal ratio (a ratio of the stomatal index of a fossil plant to that of a selected nearest living equivalent) have in the past relied on the use of a Carboniferous standard. The application of a new standard based on the present-day carbon dioxide level is reported here for comparison. The resultant ranges of palaeo-carbon dioxide estimates made from standardized fossil stomatal ratio data are in good agreement with both carbon isotopic data from terrestrial and marine sources and long-term carbon cycle modelling estimates for all the time periods studied. These data indicate elevated atmospheric carbon dioxide concentrations during the Early Devonian, Middle Jurassic and Middle Eocene, and reduced

  10. POPCYCLE: a computer code for calculating nuclear and fossil plant levelized life-cycle power costs

    SciTech Connect

    Hardie, R.W.

    1982-02-01

    POPCYCLE, a computer code designed to calculate levelized life-cycle power costs for nuclear and fossil electrical generating plants is described. Included are (1) derivations of the equations and a discussion of the methodology used by POPCYCLE, (2) a description of the input required by the code, (3) a listing of the input for a sample case, and (4) the output for a sample case.

  11. Paleoclimate from fossil plants and application to the early Cenozoic Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Wing, S. L.

    2011-12-01

    Wladimir Köppen called vegetation "crystallized, visible climate," and his metaphor encouraged paleobotanists to climb the chain of inference from fossil plants to paleovegetation to paleoclimate. Inferring paleovegetation from fossils has turned out to be very difficult, however, and today most paleobotanical methods for inferring paleoclimate do not try to reconstruct paleovegetation as a first step. Three major approaches are widely use to infer paleoclimate from plant fossils: 1) phylogenetic inferences rely on the climatic distributions of extant relatives of fossils, 2) morphological inferences use present-day correlations of climate with plant morphology (e.g, leaf shape, wood anatomy), and 3) chemical inferences rely on correlations between climate and the stable isotopic composition of plants or organic compounds. Each approach makes assumptions that are hard to verify. Phylogenetic inference depends on accurate identification of fossils, and also assumes that evolution and/or extinction has not shifted the climatic distributions of plant lineages through time. On average this assumption is less valid for older time periods, but probably it is not radically wrong for the early Cenozoic. Morphological approaches don't require taxonomic identification of plant fossils, but do assume that correlations between plant form and climate have been constant over time. This assumption is bolstered if the ecophysiological cause of the morphology-climate correlation is well understood, but often it isn't. Stable isotopic approaches assume that present-day correlations between isotopic composition and climate apply to the past. Commonly the chemical and physiological mechanisms responsible for the correlation are moderately well known, but often the variation among different taxonomic and functional groups of plants is poorly characterized. In spite of limitations and uncertainties on all methods for inferring paleoclimate from fossil plants, broad patterns emerge from

  12. Potentially carcinogenic species emitted to the atmosphere by fossil-fueled power plants.

    PubMed Central

    Natusch, D F

    1978-01-01

    The identities and physicochemical characteristics of potentially carcinogenic species emitted to the atmosphere by fossil-fueled power plants are presented and discussed. It is pointed out that many so-called carcinogens are preferentially concentrated on the surface of respirable fly ash particles thus enabling them to come into intimate contact with lung tissues when inhaled. Relatively little information is available about the identities of particulate polycyclic organic compounds whose emission from coal fired power plants may well be substantially greater than hitherto supposed. The importance of chemical changes, which several species may undergo following emission (but prior to inhalation) in determining their potential carcinogenic impact, is stressed. PMID:648494

  13. Evidence of land plant affinity for the Devonian fossil Protosalvinia (Foerstia)

    USGS Publications Warehouse

    Romankiw, L.A.; Hatcher, P.G.; Roen, J.B.

    1988-01-01

    The Devonian plant fossil Protosalvinia (Foerstia) has been examined by solid-state 13C nuclear magnetic resonance spectroscopy (NMR) and pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS). Results of these studies reveal that the chemical structure of Protosalvinia is remarkably similar to that of coalified wood. A well-defined phenolic carbon peak in the NMR spectra and the appearance of phenol and alkylated phenols in pyrolysis products are clearly indicative of lignin-like compounds. These data represent significant new information on the chemical nature of Protosalvinia and provide the first substantial organic geochemical evidence for land plant affinity. -Authors

  14. Fossil-fueled power plants as a source of atmospheric carbon monoxide.

    PubMed

    Nicks, D K; Holloway, J S; Ryerson, T B; Dissly, R W; Parrish, D D; Frost, G J; Trainer, M; Donnelly, S G; Schauffler, S; Atlas, E L; Hübler, G; Sueper, D T; Fehsenfeld, F C

    2003-02-01

    Elevated carbon monoxide (CO) mixing ratios in excess of those derived from emissions inventories have been observed in plumes from one gas- and coal-fired power plant and three of four lignite coal-fired electric utility power plants observed in east and central Texas. Observations of elevated CO on days characterized by differing wind directions show that CO emissions from the lignite plants were relatively constant over time and cannot be ascribed to separate sources adjacent to the power plants. These three plants were found to be emitting CO at rates 22 to 34 times those tabulated in State and Federal emissions inventories. Elevated CO emissions from the gas- and coal-fired plant were highly variable on time scales of hours to days, in one case changing by a factor of 8 within an hour. Three other fossil-fueled power plants, including one lignite-fired plant observed during this study, did not emit substantial amounts of CO, suggesting that a combination of plant operating conditions and the use of lignite coal may contribute to the enhanced emissions. Observed elevated CO emissions from the three lignite plants, if representative of average operating conditions, represent an additional 30% of the annual total CO emissions from point sources for the state of Texas.

  15. RADIOACTIVITY IN THE ATMOSPHERIC EFFLUENTS OF POWER PLANTS THAT USE FOSSIL FUELS.

    PubMed

    EISENBUD, M; PETROW, H G

    1964-04-17

    Analysis of the fly ash produced by combustion of pulverized Appalachian coal has shown that a 1000-megawatt coal-burning power plant will discharge into the atmosphere from about 28 millicuries to nearly 1 curie per year of radium-226 and radium-228. An oil-burning plant of similar size will discharge about 0.5 millicurie of radium per year. Comparison of these data with data on the release of fission products from nuclear-powered generating stations shows that when the physical and biological properties of the various radionuclides are taken into consideration, the conventional fossil-fueled plants discharge relatively greater quantities of radioactive materials into the atmosphere than nuclearpowered plants of comparable size.

  16. Solar-Augment Potential of U.S. Fossil-Fired Power Plants

    SciTech Connect

    Turchi, C.; Langle, N.; Bedilion, R.; Libby, C.

    2011-02-01

    Concentrating Solar Power (CSP) systems utilize solar thermal energy for the generation of electric power. This attribute makes it relatively easy to integrate CSP systems with fossil-fired power plants. The 'solar-augment' of fossil power plants offers a lower cost and lower risk alternative to stand-alone solar plant construction. This study ranked the potential to add solar thermal energy to coal-fired and natural gas combined cycle (NGCC) plants found throughout 16 states in the southeast and southwest United States. Each generating unit was ranked in six categories to create an overall score ranging from Excellent to Not Considered. Separate analysis was performed for parabolic trough and power tower technologies due to the difference in the steam temperatures that each can generate. The study found a potential for over 11 GWe of parabolic trough and over 21 GWe of power tower capacity. Power towers offer more capacity and higher quality integration due to the greater steam temperatures that can be achieved. The best sites were in the sunny southwest, but all states had at least one site that ranked Good for augmentation.

  17. The Life Assessment of Steam Turbine Rotors for Fossil Power Plants

    NASA Astrophysics Data System (ADS)

    Chang, Sungho; Song, Geewook; Kim, Bumshin; Hyun, Jungseb; Ha, Jeongsoo

    The operational mode of thermal power plants has been changed from base load to duty cycle. From the changeover, fossil power plants cannot avoid frequent thermal transient states, for example, start up and stop, which results in thermal fatigue damage at the heavy section components. The rotor is the highest capital cost component in a steam turbine and requires long outage for replacing with a new one. For an optimized power plant operational life, inspection management of the rotor is necessary. It is known in general that the start-up and shutdown operations greatly affect the steam turbine life. The start-up operational condition is especially severe because of the rapid temperature and rotational speed increase, which causes damage and reduction of life of the main components life of the steam turbine. The start-up stress of a rotor which is directly related to life is composed of thermal and rotational stresses. The thermal stress is due to the variation of steam flow temperature and rotational stress is due to the rotational speed of the turbine. In this paper, the analysis method for the start-up stress of a rotor is proposed, which considers simultaneously temperature and rotational speed transition, and includes a case study regarding a 500MW fossil power plant steam turbine rotor. Also, the method of quantitative damage estimation for fatigue-creep damage to operational conditions, is described. The method can be applied to find weak points for fatigue-creep damage. Using the method, total life consumption can be obtained, and can be also be used for determining future operational modes and life extension of old fossil power units.

  18. Evaluation of plant biomass resources available for replacement of fossil oil

    PubMed Central

    Henry, Robert J

    2010-01-01

    The potential of plants to replace fossil oil was evaluated by considering the scale of production required, the area of land needed and the types of plants available. High yielding crops (50 tonnes/ha) that have a high conversion efficiency (75%) would require a global land footprint of around 100 million ha to replace current (2008) oil consumption. Lower yielding or less convertible plants would require a larger land footprint. Domestication of new species as dedicated energy crops may be necessary. A systematic analysis of higher plants and their current and potential uses is presented. Plant biotechnology provides tools to improve the prospects of replacing oil with plant-derived biomass by increasing the amount of biomass produced per unit area of land and improving the composition of the biomass to increase the efficiency of conversion to biofuel and biomaterials. Options for the production of high value coproducts and the expression of processing aids such as enzymes in the plant may add further value to plants as bioenergy resources. PMID:20070873

  19. H. Julian Allen

    NASA Technical Reports Server (NTRS)

    1957-01-01

    H. Julian Allen stands beside the observation window of the 8 x 7 foot test section of the NACA Ames Unitary Plan Wind Tunnel. H. Julian Allen is best known for his 'Blunt Body Theory' of aerodynamics, a design technique for alleviating the severe re-entry heating problem which was then delaying the development of ballistic missiles. His findings revolutionized the fundamental design of ballistic missle re-entry shapes. Subsequently, applied research led to applications of the 'blunt' shape to ballistic missles and spacecraft which were intended to re-enter the Earth's atmosphere. This application led to the design of ablative heat shields that protected the Mercury, Gemini and Apollo astronauts as their space capsules re- entered the Earth's atmosphere. 'Harvey' Allen as he was called by most, was not only a brilliant scientist and aeronautical engineer but was also admired for his kindness, thoughtfulness and sense of humor. Among his many other accomplishments, Harvey Allen served as Center Director of the NASA Ames Research Center from 1965 to 1969. He died of a heart attack on January 29, 1977 at the age of 66.

  20. Further discovery of some Carboniferous plant fossils from Tanjung Mat Amin, Trengganu, Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Ohana, T.; Kimura, T.; Khoo, T. T.

    Carboniferous Euramerican plant fossils Rhacopteris sp., Sphenopteridium sp. and Sphenopteris sp. have been found in a new locality at Tanjung Mat Amin, Trengganu. These genera belong to the Kuantan Flora which was widespread in the part of the Eastern Belt of Peninsular Malaysia north of the Pahang River (Kuantan Flora terrain) during the Carboniferous. The existence of the Kuantan Flora indicates a warm humid Carboniferous. Any palaeogeographic reconstruction of this part of Peninsular Malaysia will have to place it in the low latitudes during the Carboniferous.

  1. Chemical and microscopical characterization of inner seed coats of fossil water plants

    NASA Astrophysics Data System (ADS)

    van Bergen, P. F.; Collinson, M. E.; Damsté, J. S. Sinninghe; de Leeuw, J. W.

    1994-01-01

    Inner seed coat layers (tegmens) of four different species of fossil water plants have been analyzed using light microscopy, scanning- and transmission-electron microscopy, and Curie-point pyrolysis. Microscopical analysis of the tegmens show two layers both comparable with a cuticle. Furthermore, the pyrolysates revealed the presence of highly aliphatic macromolecules comparable with cutan. The resistant constituents in the tegmens of two of the species also contained tocopheryl units which may serve as an additional source for prist-1-ene in pyrolysates of kerogens or of pristane upon natural thermodegradation.

  2. A proposed origin for fossilized Pennsylvanian plant cuticles by pyrite oxidation (Sydney Coalfield, Nova Scotia, Canada)

    USGS Publications Warehouse

    Zodrow, E.L.; Mastalerz, Maria

    2009-01-01

    Fossilized cuticles, though rare in the roof rocks of coal seam in the younger part of the Pennsylvanian Sydney Coalfield, Nova Scotia, represent nearly all of the major plant groups. Selected for investigation, by methods of Fourier transform infrared spectroscopy (FTIR) and elemental analysis, are fossilized cuticles (FCs) and cuticles extracted from compressions by Schulze's process (CCs) of Alethopteris ambigua. These investigations are supplemented by FTIR analysis of FCs and CCs of Cordaites principalis, and a cuticle-fossilized medullosalean(?) axis. The purpose of this study is threefold: (1) to try to determine biochemical discriminators between FCs and CCs of the same species using semi-quantitative FTIR techniques; (2) to assess the effects chemical treatments have, particularly Schulze's process, on functional groups; and most importantly (3) to study the primary origin of FCs. Results are equivocal in respect to (1); (2) after Schulze's treatment aliphatic moieties tend to be reduced relative to oxygenated groups, and some aliphatic chains may be shortened; and (3) a primary chemical model is proposed. The model is based on a variety of geological observations, including stratal distribution, clay and pyrite mineralogies associated with FCs and compressions, and regional geological structure. The model presupposes compression-cuticle fossilization under anoxic conditions for late authigenic deposition of sub-micron-sized pyrite on the compressions. Rock joints subsequently provided conduits for oxygen-enriched ground-water circulation to initiate in situ pyritic oxidation that produced sulfuric acid for macerating compressions, with resultant loss of vitrinite, but with preservation of cuticles as FCs. The timing of the process remains undetermined, though it is assumed to be late to post-diagenetic. Although FCs represent a pathway of organic matter transformation (pomd) distinct from other plant-fossilization processes, global applicability of the

  3. Morphological preservation of carbonaceous plant fossils in blueschist metamorphic rocks from New Zealand.

    PubMed

    Galvez, M E; Beyssac, O; Benzerara, K; Bernard, S; Menguy, N; Cox, S C; Martinez, I; Johnston, M R; Brown, G E

    2012-03-01

    Morphological and chemical evidence of ancient life is widespread in sedimentary rocks retrieved from shallow depths in the Earth's crust. Metamorphism is highly detrimental to the preservation of biological information in rocks, thus limiting the geological record in which traces of life might be found. Deformation and increasing pressure/temperature during deep burial may alter the morphology as well as the composition and structure of both the organic and mineral constituents of fossils. However, microspore fossils have been previously observed in intensely metamorphosed rocks. It has been suggested that their small size, and/or the nature of the polymer composing their wall, and/or the mineralogy of their surrounding matrix were key parameters explaining their exceptional preservation. Here, we describe the remarkable morphological preservation of plant macrofossils in blueschist metamorphic rocks from New Zealand containing lawsonite. Leaves and stems can be easily identified at the macroscale. At the microscale, polygonal structures with walls mineralized by micas within the leaf midribs and blades may derive from the original cellular ultrastructure or, alternatively, from the shrinkage during burial of the gelified remnants of the leaves in an abiotic process. Processes and important parameters involved in the remarkable preservation of these fossils during metamorphism are discussed. Despite the excellent morphological preservation, the initial biological polymers have been completely transformed to graphitic carbonaceous matter down to the nanometer scale. This occurrence demonstrates that plant macrofossils may experience major geodynamic processes such as metamorphism and exhumation involving deep changes and homogenization of their carbon chemistry and structure but still retain their morphology with remarkable integrity even if they are not shielded by any hard-mineralized concretion.

  4. New acoustic techniques for leak detection in fossil fuel plant components

    NASA Astrophysics Data System (ADS)

    Parini, G.; Possa, G.

    Two on-line acoustic monitoring techniques for leak detection in feedwater preheaters and boilers of fossil fuel power plants are presented. The leak detection is based on the acoustic noise produced by the turbulent leak outflow. The primary sensors are piezoelectric pressure transducers, installed near the feedwater preheater inlets, in direct contact with the water, or mounted on boiler observation windows. The frequency band of the auscultation ranges from a few kHz, to 10 to 15 kHz. The signals are characterized by their rms value, continuously recorded by means of potentiometric strip chart recorders. The leak occurrence is signalled by the signal rms overcoming predetermined threshold levels. Sensitivity, reliability, acceptance in plant control practice, and costs-benefits balance are satisfactory.

  5. Green Web or megabiased clock? Plant fossils from Gondwanan Patagonia speak on evolutionary radiations.

    PubMed

    Wilf, Peter; Escapa, Ignacio H

    2015-07-01

    Evolutionary divergence-age estimates derived from molecular 'clocks' are frequently correlated with paleogeographic, paleoclimatic and extinction events. One prominent hypothesis based on molecular data states that the dominant pattern of Southern Hemisphere biogeography is post-Gondwanan clade origins and subsequent dispersal across the oceans in a metaphoric 'Green Web'. We tested this idea against well-dated Patagonian fossils of 19 plant lineages, representing organisms that actually lived on Gondwana. Most of these occurrences are substantially older than their respective, often post-Gondwanan molecular dates. The Green Web interpretation probably results from directional bias in molecular results. Gondwanan history remains fundamental to understanding Southern Hemisphere plant radiations, and we urge significantly greater caution when using molecular dating to interpret the biological impacts of geological events.

  6. Expression of a Flax Allene Oxide Synthase cDNA Leads to Increased Endogenous Jasmonic Acid (JA) Levels in Transgenic Potato Plants but Not to a Corresponding Activation of JA-Responding Genes.

    PubMed Central

    Harms, K.; Atzorn, R.; Brash, A.; Kuhn, H.; Wasternack, C.; Willmitzer, L.; Pena-Cortes, H.

    1995-01-01

    Both jasmonic acid (JA) and its methyl ester, methyl jasmonate (MeJA), are thought to be significant components of the signaling pathway regulating the expression of plant defense genes in response to various stresses. JA and MeJA are plant lipid derivatives synthesized from [alpha]-linolenic acid by a lipoxygenase-mediated oxygenation leading to 13-hydroperoxylinolenic acid, which is subsequently transformed by the action of allene oxide synthase (AOS) and additional modification steps. AOS converts lipoxygenase-derived fatty acid hydroperoxide to allene epoxide, which is the precursor for JA formation. Overexpression of flax AOS cDNA under the regulation of the cauliflower mosaic virus 35S promoter in transgenic potato plants led to an increase in the endogenous level of JA. Transgenic plants had six- to 12-fold higher levels of JA than the nontransformed plants. Increased levels of JA have been observed when potato and tomato plants are mechanically wounded. Under these conditions, the proteinase inhibitor II (pin2) genes are expressed in the leaves. Despite the fact that the transgenic plants had levels of JA similar to those found in nontransgenic wounded plants, pin2 genes were not constitutively expressed in the leaves of these plants. Transgenic plants with increased levels of JA did not show changes in water state or in the expression of water stress-responsive genes. Furthermore, the transgenic plants overexpressing the flax AOS gene, and containing elevated levels of JA, responded to wounding or water stress by a further increase in JA and by activating the expression of either wound- or water stress-inducible genes. Protein gel blot analysis demonstrated that the flax-derived AOS protein accumulated in the chloroplasts of the transgenic plants. PMID:12242357

  7. EPICS: Allen-Bradley hardware reference manual

    SciTech Connect

    Nawrocki, G.

    1993-04-05

    This manual covers the following hardware: Allen-Bradley 6008 -- SV VMEbus I/O scanner; Allen-Bradley universal I/O chassis 1771-A1B, -A2B, -A3B, and -A4B; Allen-Bradley power supply module 1771-P4S; Allen-Bradley 1771-ASB remote I/O adapter module; Allen-Bradley 1771-IFE analog input module; Allen-Bradley 1771-OFE analog output module; Allen-Bradley 1771-IG(D) TTL input module; Allen-Bradley 1771-OG(d) TTL output; Allen-Bradley 1771-IQ DC selectable input module; Allen-Bradley 1771-OW contact output module; Allen-Bradley 1771-IBD DC (10--30V) input module; Allen-Bradley 1771-OBD DC (10--60V) output module; Allen-Bradley 1771-IXE thermocouple/millivolt input module; and the Allen-Bradley 2705 RediPANEL push button module.

  8. Palaeoclimate reconstruction within the upper Eocene in central Germany using fossil plants

    NASA Astrophysics Data System (ADS)

    Moraweck, Karolin; Kunzmann, Lutz; Uhl, Dieter; Kleber, Arno

    2013-04-01

    The Eocene has been commonly called "The world`s last greenhouse period" covering the Paleocene-Eocene Thermal Maximum (PETM) as well as the Eocene-Oligocene turnover. In the mid-latitudes of Europe this turnover was characterized by pronounced climatic changes from subtropical towards temperate conditions that were accompanied by significant vegetational changes on land. Fossil plants are regarded as excellent palaeoenvironmental proxies, because leaf physiognomy often reflects climate conditions. The study site, the Paleogene Weißelster basin in central Germany, including fluvial, estuarine and lacustrine deposits, provides several excellently preserved megafloras for reconstructions of terrestrial palaeoclimate. For our case study we used material from different stratigraphic horizons within the late Eocene Zeitz megafloral assemblage recovered from the open-cast mines of Profen and Schleenhain. These horizons cover a time interval of ca. 3 Ma. The Zeitz megafloral assemblage ("Florenkomplex") was characterized by mainly evergreen, notophyllous vegetation, consisting of warm-temperate to subtropical elements. Tropical species are present but very rare. To infer the regional climatic conditions and putative climate changes from these fossil plants we compare proxy data obtained by the application of standard methods for quantitative reconstruction of palaeoclimate data: the coexistence approach (CA), leaf margin analysis (LMA) and Climate Leaf Analysis Multivariate Program (CLAMP).Before the CA was applied to the material the list of putative nearest living relative species (NLR) was carefully revisited and partly revised. In case of the LMA approach information of so-called "silent taxa" (fossil species preserved by diaspores, leaf margin state is inferred from NLR data) were partly included in the data set. The four floras from the Zeitz megafloral assemblage show slightly different floral compositions caused by various taphonomic processes. An aim of the

  9. Robotic applications in PSE and G's nuclear and fossil power plants

    SciTech Connect

    Roman, H.T. )

    1993-09-01

    Robots are rapidly becoming a strategic technology in the electric utility industry. Since 1983, over 200 applications of these devices have been documented, often resulting in significant time and manpower savings. In nuclear plants, these devices have reduced radiation exposure to human workers and also reduced radiation exposure to human workers and also reduced plant downtime. Public Service Electric and Gas (PSE and G) Company is a nationally recognized leader in this technology. Since 1987, the company has spent $1.6 million on robotic hardware and development projects for use at its Salem (2 PWRS) and Hope Creek (1 BWR) nuclear plants. Savings to date from these investments has exceeded $5 million. Recently, PSE and G has expanded its robotic application efforts to include fossil plants, with many exciting new concepts. This paper will discuss the state-of-the-art mobile robots in the utility industry, and use of PSE and G's pioneering work in this area as a case study; discussing the cost, performance and benefits of specific applications.

  10. Device for separating CO2 from fossil-fueled power plant emissions

    DOEpatents

    Burchell, Timothy D [Oak Ridge, TN; Judkins, Roddie R [Knoxville, TN; Wilson, Kirk A [Knoxville, TN

    2002-04-23

    A gas separation device includes an inner conduit, and a concentric outer conduit. An electrically conductive filter media, preferably a carbon fiber composite molecular sieve, is provided in the annular space between the inner conduit and the outer conduit. Gas flows through the inner conduit and the annular space between the inner conduit and the outer conduit, so as to contact the filter media. The filter media preferentially adsorbs at least one constituent of the gas stream. The filter media is regenerated by causing an electric current to flow through the filter media. The inner conduit and outer conduit are preferably electrically conductive whereby the regeneration of the filter media can be electrically stimulated. The invention is particularly useful for the removal of CO.sub.2 from the exhaust gases of fossil-fueled power plants.

  11. Comparison of manual and automated pretreatment methods for AMS radiocarbon dating of plant fossils

    USGS Publications Warehouse

    Bradley, L.-A.; Stafford, Thomas W.

    1994-01-01

    A new automated pretreatment system for the preparation of materials submitted for accelerator mass spectrometry (AMS) analysis is less time-consuming and results in a higher sample yield. The new procedure was tested using two groups of plant fossils: one group was pretreated using the traditional method, and the second, using the automated pretreatment apparatus. The time it took to complete the procedure and the amount of sample material remaining were compared. The automated pretreatment apparatus proved to be more than three times faster and, in most cases, produced a higher yield. A darker discoloration of the KOH solutions was observed indicating that the automated system is more thorough in removing humates from the specimen compared to the manual method. -Authors

  12. Virtual taphonomy using synchrotron tomographic microscopy reveals cryptic features and internal structure of modern and fossil plants.

    PubMed

    Smith, Selena Y; Collinson, Margaret E; Rudall, Paula J; Simpson, David A; Marone, Federica; Stampanoni, Marco

    2009-07-21

    While more commonly applied in zoology, synchrotron radiation X-ray tomographic microscopy (SRXTM) is well-suited to nondestructive study of the morphology and anatomy of both fossil and modern plants. SRXTM uses hard X-rays and a monochromatic light source to provide high-resolution data with little beam-hardening, resulting in slice data with clear boundaries between materials. Anatomy is readily visualized, including various planes of section from a single specimen, as clear as in traditional histological sectioning at low magnifications. Thus, digital sectioning of rare or difficult material is possible. Differential X-ray attenuation allows visualization of different layers or chemistries to enable virtual 3-dimensional (3D) dissections of material. Virtual potential fossils can be visualized and digital tissue removal reveals cryptic underlying morphology. This is essential for fossil identification and for comparisons between assemblages where fossils are preserved by different means. SRXTM is a powerful approach for botanical studies using morphology and anatomy. The ability to gain search images in both 2D and 3D for potential fossils gives paleobotanists a tool--virtual taphonomy--to improve our understanding of plant evolution and paleobiogeography.

  13. Virtual taphonomy using synchrotron tomographic microscopy reveals cryptic features and internal structure of modern and fossil plants

    PubMed Central

    Smith, Selena Y.; Collinson, Margaret E.; Rudall, Paula J.; Simpson, David A.; Marone, Federica; Stampanoni, Marco

    2009-01-01

    While more commonly applied in zoology, synchrotron radiation X-ray tomographic microscopy (SRXTM) is well-suited to nondestructive study of the morphology and anatomy of both fossil and modern plants. SRXTM uses hard X-rays and a monochromatic light source to provide high-resolution data with little beam-hardening, resulting in slice data with clear boundaries between materials. Anatomy is readily visualized, including various planes of section from a single specimen, as clear as in traditional histological sectioning at low magnifications. Thus, digital sectioning of rare or difficult material is possible. Differential X-ray attenuation allows visualization of different layers or chemistries to enable virtual 3-dimensional (3D) dissections of material. Virtual potential fossils can be visualized and digital tissue removal reveals cryptic underlying morphology. This is essential for fossil identification and for comparisons between assemblages where fossils are preserved by different means. SRXTM is a powerful approach for botanical studies using morphology and anatomy. The ability to gain search images in both 2D and 3D for potential fossils gives paleobotanists a tool—virtual taphonomy—to improve our understanding of plant evolution and paleobiogeography. PMID:19574457

  14. Revisiting the origin and diversification of vascular plants through a comprehensive Bayesian analysis of the fossil record.

    PubMed

    Silvestro, Daniele; Cascales-Miñana, Borja; Bacon, Christine D; Antonelli, Alexandre

    2015-07-01

    Plants have a long evolutionary history, during which mass extinction events dramatically affected Earth's ecosystems and its biodiversity. The fossil record can shed light on the diversification dynamics of plant life and reveal how changes in the origination-extinction balance have contributed to shaping the current flora. We use a novel Bayesian approach to estimate origination and extinction rates in plants throughout their history. We focus on the effect of the 'Big Five' mass extinctions and on estimating the timing of origin of vascular plants, seed plants and angiosperms. Our analyses show that plant diversification is characterized by several shifts in origination and extinction rates, often matching the most important geological boundaries. The estimated origin of major plant clades predates the oldest macrofossils when considering the uncertainties associated with the fossil record and the preservation process. Our findings show that the commonly recognized mass extinctions have affected each plant group differently and that phases of high extinction often coincided with major floral turnovers. For instance, after the Cretaceous-Paleogene boundary we infer negligible shifts in diversification of nonflowering seed plants, but find significantly decreased extinction in spore-bearing plants and increased origination rates in angiosperms, contributing to their current ecological and evolutionary dominance.

  15. Model-based monitoring and fault diagnosis of fossil power plant process units using Group Method of Data Handling.

    PubMed

    Li, Fan; Upadhyaya, Belle R; Coffey, Lonnie A

    2009-04-01

    This paper presents an incipient fault diagnosis approach based on the Group Method of Data Handling (GMDH) technique. The GMDH algorithm provides a generic framework for characterizing the interrelationships among a set of process variables of fossil power plant sub-systems and is employed to generate estimates of important variables in a data-driven fashion. In this paper, ridge regression techniques are incorporated into the ordinary least squares (OLS) estimator to solve regression coefficients at each layer of the GMDH network. The fault diagnosis method is applied to feedwater heater leak detection with data from an operating coal-fired plant. The results demonstrate the proposed method is capable of providing an early warning to operators when a process fault or an equipment fault occurs in a fossil power plant.

  16. Inputs of fossil carbon from wastewater treatment plants to U.S. Rivers and oceans

    USGS Publications Warehouse

    Griffith, D.R.; Barnes, R.T.; Raymond, P.A.

    2009-01-01

    Every day more than 500 million cubic meters of treated wastewater are discharged into rivers, estuaries, and oceans, an amount slightly less than the average flow of the Danube River. Typically, wastewaters have high organic carbon (OC) concentrations and represent a large fraction of total river flow and a higher fraction of river OC in densely populated watersheds. Here, we report the first direct measurements of radiocarbon (14C) in municipal wastewater treatment plant (WWTP) effluent. The radiocarbon ages of particulate and dissolved organic carbon (POC and DOC) in effluent are old and relatively uniform across a range of WWTPs in New York and Connecticut. Wastewater DOC has a mean radiocarbon age of 1630 ?? 500 years B.P. and a mean ??13C of -26.0 ?? 1???. Mass balance calculations indicate that 25% of wastewater DOC is fossil carbon, which is likely derived from petroleumbased household products such as detergents and pharmaceuticals. Thesefindings warrant reevaluation of the "apparent age" of riverine DOC, the total flux of petroleum carbon to U.S. oceans, and OC source assignments in waters impacted by sewage. ?? 2009 American Chemical Society.

  17. Inputs of fossil carbon from wastewater treatment plants to U.S. rivers and oceans.

    PubMed

    Griffith, David R; Barnes, Rebecca T; Raymond, Peter A

    2009-08-01

    Every day more than 500 million cubic meters of treated wastewater are discharged into rivers, estuaries, and oceans, an amount slightly less than the average flow of the Danube River. Typically, wastewaters have high organic carbon (OC) concentrations and represent a large fraction of total river flow and a higher fraction of river OC in densely populated watersheds. Here, we report the first direct measurements of radiocarbon (14C) in municipal wastewater treatment plant (WWTP) effluent. The radiocarbon ages of particulate and dissolved organic carbon (POC and DOC) in effluent are old and relatively uniform across a range of WWTPs in New York and Connecticut Wastewater DOC has a mean radiocarbon age of 1630 +/- 500 years B.P. and a mean delta13C of -26.0 +/- 1 per thousand. Mass balance calculations indicate that 25% of wastewater DOC is fossil carbon, which is likely derived from petroleum-based household products such as detergents and pharmaceuticals. These findings warrant reevaluation of the "apparent age" of riverine DOC, the total flux of petroleum carbon to U.S. oceans, and OC source assignments in waters impacted by sewage.

  18. A 300-million-year record of atmospheric carbon dioxide from fossil plant cuticles

    NASA Astrophysics Data System (ADS)

    Retallack, Gregory J.

    2001-05-01

    To understand better the link between atmospheric CO2 concentrations and climate over geological time, records of past CO2 are reconstructed from geochemical proxies. Although these records have provided us with a broad picture of CO2 variation throughout the Phanerozoic eon (the past 544Myr), inconsistencies and gaps remain that still need to be resolved. Here I present a continuous 300-Myr record of stomatal abundance from fossil leaves of four genera of plants that are closely related to the present-day Ginkgo tree. Using the known relationship between leaf stomatal abundance and growing season CO2 concentrations, I reconstruct past atmospheric CO2 concentrations. For the past 300Myr, only two intervals of low CO2 (<1,000p.p.m.v.) are inferred, both of which coincide with known ice ages in Neogene (1-8Myr) and early Permian (275-290Myr) times. But for most of the Mesozoic era (65-250Myr), CO2 levels were high (1,000-2,000p.p.m.v.), with transient excursions to even higher CO2 (>2,000p.p.m.v.) concentrations. These results are consistent with some reconstructions of past CO2 (refs 1, 2) and palaeotemperature records, but suggest that CO2 reconstructions based on carbon isotope proxies may be compromised by episodic outbursts of isotopically light methane. These results support the role of water vapour, methane and CO2 in greenhouse climate warming over the past 300Myr.

  19. Exceptionally well preserved late Quaternary plant and vertebrate fossils from a blue hole on Abaco, The Bahamas

    PubMed Central

    Steadman, David W.; Franz, Richard; Morgan, Gary S.; Albury, Nancy A.; Kakuk, Brian; Broad, Kenneth; Franz, Shelley E.; Tinker, Keith; Pateman, Michael P.; Lott, Terry A.; Jarzen, David M.; Dilcher, David L.

    2007-01-01

    We report Quaternary vertebrate and plant fossils from Sawmill Sink, a “blue hole” (a water-filled sinkhole) on Great Abaco Island, The Bahamas. The fossils are well preserved because of deposition in anoxic salt water. Vertebrate fossils from peat on the talus cone are radiocarbon-dated from ≈4,200 to 1,000 cal BP (Late Holocene). The peat produced skeletons of two extinct species (tortoise Chelonoidis undescribed sp. and Caracara Caracara creightoni) and two extant species no longer in The Bahamas (Cuban crocodile, Crocodylus rhombifer; and Cooper's or Gundlach's Hawk, Accipiter cooperii or Accipiter gundlachii). A different, inorganic bone deposit on a limestone ledge in Sawmill Sink is a Late Pleistocene owl roost that features lizards (one species), snakes (three species), birds (25 species), and bats (four species). The owl roost fauna includes Rallus undescribed sp. (extinct; the first Bahamian flightless rail) and four other locally extinct species of birds (Cooper's/Gundlach's Hawk, A. cooperii/gundlachii; flicker Colaptes sp.; Cave Swallow, Petrochelidon fulva; and Eastern Meadowlark, Sturnella magna) and mammals (Bahamian hutia, Geocapromys ingrahami; and a bat, Myotis sp.). The exquisitely preserved fossils from Sawmill Sink suggest a grassy pineland as the dominant plant community on Abaco in the Late Pleistocene, with a heavier component of coppice (tropical dry evergreen forest) in the Late Holocene. Important in its own right, this information also will help biologists and government planners to develop conservation programs in The Bahamas that consider long-term ecological and cultural processes. PMID:18077421

  20. Alkane distribution and carbon isotope composition in fossil leaves: An interpretation of plant physiology in the geologic past

    NASA Astrophysics Data System (ADS)

    Graham, H. V.; Freeman, K. H.

    2014-12-01

    The relative chain-length distribution and carbon-isotope composition of n-alkanes extracted from sedimentary rocks are important geochemical tools for investigating past terrestrial ecosystems. Alkanes preserved in ancient sediments are assumed to be contemporaneous, derived from the same ecosystem, and integrated from the biomass present on the landscape at the time of deposition. Further, there is an underlying assumption that ancient plants exhibited the same metabolic and physiological responses to climate conditions that are observed for modern plants. Interpretations of alkane abundances and isotopic signatures are complicated by the strong influence of phylogenetic affiliation and ecological factors, such as canopy structure. A better understanding of how ecosystem and taxa influence alkane properties, including homologue abundance patterns and leaf-lipid carbon isotope fractionation would help strengthen paleoecological interpretations based on these widely employed plant biomarkers. In this study, we analyze the alkane chain-length distribution and carbon-isotope composition of phytoleim and alkanes (d13Cleaf and d13Clipid) extracted from a selection of Cretaceous and Paleocene fossil leaves from the Guaduas and Cerrejon Formations of Colombia. These data were compared with data for the same families in a modern analogue biome. Photosynthetic and biosynthetic fractionation (∆leaf and elipid) values determined from the fossil material indicate carbon metabolism patterns were similar to modern plants. Fossil data were incorporated in a biomass-weighted mixing model to represent the expected lipid complement of sediment arising from this ecosystem and compared with alkane measurements from the rock matrix. Modeled and observed isotopic and abundance patterns match well for alkane homologs most abundant in plants (i.e., n-C27 to n-C33). The model illustrates the importance of understanding biases in litter flux and taphonomic pressures inherent in the

  1. Can hybrid solar-fossil power plants mitigate CO2 at lower cost than PV or CSP?

    PubMed

    Moore, Jared; Apt, Jay

    2013-03-19

    Fifteen of the United States and several nations require a portion of their electricity come from solar energy. We perform an engineering-economic analysis of hybridizing concentrating solar thermal power with fossil fuel in an Integrated Solar Combined Cycle (ISCC) generator. We construct a thermodynamic model of an ISCC plant in order to examine how much solar and fossil electricity is produced and how such a power plant would operate, given hourly solar resource data and hourly electricity prices. We find that the solar portion of an ISCC power plant has a lower levelized cost of electricity than stand-alone solar power plants given strong solar resource in the US southwest and market conditions that allow the capacity factor of the solar portion of the power plant to be above 21%. From a local government perspective, current federal subsidies distort the levelized cost of electricity such that photovoltaic electricity is slightly less expensive than the solar electricity produced by the ISCC. However, if the cost of variability and additional transmission lines needed for stand-alone solar power plants are taken into account, the solar portion of an ISCC power plant may be more cost-effective.

  2. Mechanistic modelling of Middle Eocene atmospheric carbon dioxide using fossil plant material

    NASA Astrophysics Data System (ADS)

    Grein, Michaela; Roth-Nebelsick, Anita; Wilde, Volker; Konrad, Wilfried; Utescher, Torsten

    2010-05-01

    Various proxies (such as pedogenic carbonates, boron isotopes or phytoplankton) and geochemical models were applied in order to reconstruct palaeoatmospheric carbon dioxide, partially providing conflicting results. Another promising proxy is the frequency of stomata (pores on the leaf surface used for gaseous exchange). In this project, fossil plant material from the Messel Pit (Hesse, Germany) is used to reconstruct atmospheric carbon dioxide concentration in the Middle Eocene by analyzing stomatal density. We applied the novel mechanistic-theoretical approach of Konrad et al. (2008) which provides a quantitative derivation of the stomatal density response (number of stomata per leaf area) to varying atmospheric carbon dioxide concentration. The model couples 1) C3-photosynthesis, 2) the process of diffusion and 3) an optimisation principle providing maximum photosynthesis (via carbon dioxide uptake) and minimum water loss (via stomatal transpiration). These three sub-models also include data of the palaeoenvironment (temperature, water availability, wind velocity, atmospheric humidity, precipitation) and anatomy of leaf and stoma (depth, length and width of stomatal porus, thickness of assimilation tissue, leaf length). In order to calculate curves of stomatal density as a function of atmospheric carbon dioxide concentration, various biochemical parameters have to be borrowed from extant representatives. The necessary palaeoclimate data are reconstructed from the whole Messel flora using Leaf Margin Analysis (LMA) and the Coexistence Approach (CA). In order to obtain a significant result, we selected three species from which a large number of well-preserved leaves is available (at least 20 leaves per species). Palaeoclimate calculations for the Middle Eocene Messel Pit indicate a warm and humid climate with mean annual temperature of approximately 22°C, up to 2540 mm mean annual precipitation and the absence of extended periods of drought. Mean relative air

  3. Carbon Capture and Water Emissions Treatment System (CCWESTRS) at Fossil-Fueled Electric Generating Plants

    SciTech Connect

    P. Alan Mays; Bert R. Bock; Gregory A. Brodie; L. Suzanne Fisher; J. Devereux Joslin; Donald L. Kachelman; Jimmy J. Maddox; N. S. Nicholas; Larry E. Shelton; Nick Taylor; Mark H. Wolfe; Dennis H. Yankee; John Goodrich-Mahoney

    2005-08-30

    The Tennessee Valley Authority (TVA), the Electric Power Research Institute (EPRI), and the Department of Energy-National Energy Technologies Laboratory (DOE-NETL) are evaluating and demonstrating integration of terrestrial carbon sequestration techniques at a coal-fired electric power plant through the use of Flue Gas Desulfurization (FGD) system gypsum as a soil amendment and mulch, and coal fly ash pond process water for periodic irrigation. From January to March 2002, the Project Team initiated the construction of a 40 ha Carbon Capture and Water Emissions Treatment System (CCWESTRS) near TVA's Paradise Fossil Plant on marginally reclaimed surface coal mine lands in Kentucky. The CCWESTRS is growing commercial grade trees and cover crops and is expected to sequester 1.5-2.0 MT/ha carbon per year over a 20-year period. The concept could be used to meet a portion of the timber industry's needs while simultaneously sequestering carbon in lands which would otherwise remain non-productive. The CCWESTRS includes a constructed wetland to enhance the ability to sequester carbon and to remove any nutrients and metals present in the coal fly ash process water runoff. The CCWESTRS project is a cooperative effort between TVA, EPRI, and DOE-NETL, with a total budget of $1,574,000. The proposed demonstration project began in October 2000 and has continued through December 2005. Additional funding is being sought in order to extend the project. The primary goal of the project is to determine if integrating power plant processes with carbon sequestration techniques will enhance carbon sequestration cost-effectively. This goal is consistent with DOE objectives to provide economically competitive and environmentally safe options to offset projected growth in U.S. baseline emissions of greenhouse gases after 2010, achieve the long-term goal of $10/ton of avoided net costs for carbon sequestration, and provide half of the required reductions in global greenhouse gases by 2025

  4. Preservation of Plant Biomolecules and the Relevance to the Interpretation of Paleoenvironmental Signals: Tertiary Metasequoia Fossils as Examples

    NASA Astrophysics Data System (ADS)

    Yang, H.; Leng, Q.

    2004-12-01

    The degradation and preservation of biomolecules in plant tissues not only affects the inference on paleoecology of ancient plants but also bears significance in the interpretation of paleoenvironmental signals. Using a combined SEM and geochemical approach, we are able to show the source, liability, and preservation of structural biopolymers from morphologically well-preserved Metasequoia tissues from three Tertiary deposits. We detected a continuum of biomolecular preservation in this evolutionarily-conserved conifer. Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) was applied to solvent-extracted residues from both fossil leaf and wood remains in comparison with tissues from their living counterparts. The late Paleocene-early Eocene leaves from Ellesmere Island, Canadian Arctic Archipelago, exhibit the best quality of biochemical preservation and show pyrolysis products derived from labile biomolecules characterized by large amounts of polysaccharides. These labile biomolecules are the oldest record of these kinds so far characterized by the pyrolysis technology. The middle Eocene leaf tissues from Axel Heiberg Island, Canadian Arctic Archipelago, yielded slightly lesser amounts of polysaccharide moieties, but the lignin products are similar to those identified from the Ellesmere Island fossils. Compared with these Arctic materials, the Metasequoia leaves from Miocene Clarkia, Idaho, USA, show the lowest quality of molecular preservation, characterized by a dramatic reduction of polysaccharides. This continuum of relative quality of biomolecular preservation is further confirmed by SEM observations of transverse sections of these fossil leaves. The investigation revealed tissue-specific degradation, and our data support the in-situ polymerization hypothesis for the origin of long-chain homologous pairs of aliphatic n-alk-1-enes/n-alkanes as leaf alteration products. The preferential degradation and selective removal of polysaccharides may be

  5. Use of Chia Plant to Monitor Urban Fossil Fuel CO2 Emission: An Example From Irvine, CA in 2010

    NASA Astrophysics Data System (ADS)

    Xu, X.; Stills, A.; Trumbore, S.; Randerson, J. T.; Yi, J.

    2011-12-01

    Δ14CO2 is a unique tracer for quantifying anthropogenic CO2 emissions. However, monitoring 14CO2 change and distribution in an urban environment is challenging because of its large spatial and temporal variations. We have tested the potential use of a chia plant (Salvia hispanica) as an alternative way to collect a time-integrated CO2 sample for radiocarbon analysis. The results show that Δ14C of the new growth of chia sprouts and chia leaves are consistent with the Δ14C of air samples collected during the growing period, indicating the new growth has no inherited C from seeds and thus records atmospheric 14CO2. Time-integrated air samples and chia leaf samples significantly reduced the noises of Δ14CO2 in an urban environment. We report here an example of monitoring 14CO2 change in Irvine, CA from Mar 2010 to Mar 2011 utilizing such a method. The results showed a clear seasonal cycle with high (close to remote air background level) Δ14C in summer and low Δ14C in winter months in this urban area. Excess (above remote air background) fossil fuel CO2 was calculated to be closed to 0 ppm in June to about 16 ppm from November 2010 to February 2011. Monthly mean Δ14CO2 was anti-correlated with monthly mean CO mixing ratio, indicating Δ14CO2 is mainly controlled by fossil fuel CO2 mixing with clean on-shore marine air. In summary, this study has shown encouraging result that chia plant can be potentially used as a convenient and inexpensive sampling method for time-integrated atmospheric 14CO2. Combined with other annual plants this provides the opportunity to map out time-integrated fossil fuel-derived CO2 in major cities at low cost. This in turn can be used to: 1) establish a baseline for fossil fuel emissions reductions in cities in the future; 2) provide invaluable information for validating emission models.

  6. Mud fossils

    USGS Publications Warehouse

    ,

    1997-01-01

    At the close of the 18th century, the haze of fantasy and mysticism that tended to obscure the true nature of the Earth was being swept away. Careful studies by scientists showed that rocks had diverse origins. Some rock layers, containing clearly identifiable fossil remains of fish and other forms of aquatic animal and plant life, originally formed in the ocean. Other layers, consisting of sand grains winnowed clean by the pounding surf, obviously formed as beach deposits that marked the shorelines of ancient seas.

  7. Partial replacement of fossil fuel in a cement plant: risk assessment for the population living in the neighborhood.

    PubMed

    Rovira, Joaquim; Mari, Montse; Nadal, Martí; Schuhmacher, Marta; Domingo, José L

    2010-10-15

    In cement plants, the substitution of traditional fossil fuels not only allows a reduction of CO(2), but it also means to check-out residual materials, such as sewage sludge or municipal solid wastes (MSW), which should otherwise be disposed somehow/somewhere. In recent months, a cement plant placed in Alcanar (Catalonia, Spain) has been conducting tests to replace fossil fuel by refuse-derived fuel (RDF) from MSW. In July 2009, an operational test was progressively initiated by reaching a maximum of partial substitution of 20% of the required energy. In order to study the influence of the new process, environmental monitoring surveys were performed before and after the RDF implementation. Metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in soil, herbage, and air samples collected around the facility. In soils, significant decreases of PCDD/F levels, as well as in some metal concentrations were found, while no significant increases in the concentrations of these pollutants were observed. In turn, PM(10) levels remained constant, with a value of 16μgm(-3). In both surveys, the carcinogenic and non-carcinogenic risks derived from exposure to metals and PCDD/Fs for the population living in the vicinity of the facility were within the ranges considered as acceptable according to national and international standards. This means that RDF may be a successful choice in front of classical fossil fuels, being in accordance with the new EU environmental policies, which entail the reduction of CO(2) emissions and the energetic valorization of MSW. However, further long-term environmental studies are necessary to corroborate the harmlessness of RDF, in terms of human health risks.

  8. Atmospheric CO2 from the late Oligocene to early Miocene reconstructed from photosynthesis data and leaf characteristics of fossil plants

    NASA Astrophysics Data System (ADS)

    Grein, Michaela; Oehm, Christoph; Konrad, Wilfried; Utescher, Torsten; Kunzmann, Lutz; Roth-Nebelsick, Anita

    2013-04-01

    In the Cenozoic era, global climate changed from greenhouse to icehouse conditions. During the Oligocene, the comparatively cool phase in the earlier part of the late Oligocene is followed by the Late Oligocene Warming and a major glaciation event at the Oligocene-Miocene transition (Mi-1). Various studies indicate that these climate events were coupled to changes in atmospheric CO2 levels. In this study, atmospheric CO2 from the late Oligocene to the early Miocene was reconstructed by using photosynthesis data and fossil leaf characteristics. We used plant material from various sites located in Germany and Austria comprising fossil leaves of four angiosperm plant species: Platanus neptuni (Platanaceae), Quercus rhenana, Q. praerhenana and Eotrigonobalanus furcinervis (all Fagaceae). A mechanistic-theoretical approach based on stomatal parameters, photosynthesis data and gas exchange parameters was applied to model palaeoatmospheric CO2 levels. Detailed climate data of the considered sites were reconstructed as well since the mechanistic-theoretical approach requires climate data as input parameters for calculating both assimilation rate and transpiration rate. Our results indicate a steady CO2 level of about 400 ppm for all sites and therefore suggest a decoupling of CO2 and cooling/warming events for the considered time slices.

  9. Modes of fossil preservation

    USGS Publications Warehouse

    Schopf, J.M.

    1975-01-01

    The processes of geologic preservation are important for understanding the organisms represented by fossils. Some fossil differences are due to basic differences in organization of animals and plants, but the interpretation of fossils has also tended to be influenced by modes of preservation. Four modes of preservation generally can be distinguished: (1) Cellular permineralization ("petrifaction") preserves anatomical detail, and, occasionally, even cytologic structures. (2) Coalified compression, best illustrated by structures from coal but characteristic of many plant fossils in shale, preserves anatomical details in distorted form and produces surface replicas (impressions) on enclosing matrix. (3) Authigenic preservation replicates surface form or outline (molds and casts) prior to distortion by compression and, depending on cementation and timing, may intergrade with fossils that have been subject to compression. (4) Duripartic (hard part) preservation is characteristic of fossil skeletal remains, predominantly animal. Molds, pseudomorphs, or casts may form as bulk replacements following dissolution of the original fossil material, usually by leaching. Classification of the kinds of preservation in fossils will aid in identifying the processes responsible for modifying the fossil remains of both animals and plants. ?? 1975.

  10. Responses of high-elevation herbaceous plant assemblages to low glacial CO₂ concentrations revealed by fossil marmot (Marmota) teeth.

    PubMed

    McLean, Bryan S; Ward, Joy K; Polito, Michael J; Emslie, Steven D

    2014-08-01

    Atmospheric CO2 cycles of the Quaternary likely imposed major constraints on the physiology and growth of C3 plants worldwide. However, the measured record of this remains both geographically and taxonomically sparse. We present the first reconstruction of physiological responses in a late Quaternary high-elevation herbaceous plant community from the Southern Rocky Mountains, USA. We used a novel proxy-fossilized tooth enamel of yellow-bellied marmots (Marmota flaviventris)-which we developed using detailed isotopic analysis of modern individuals. Calculated C isotopic discrimination (Δ) of alpine plants was nearly 2 ‰ lower prior to the Last Glacial Maximum than at present, a response almost identical to that of nonherbaceous taxa from lower elevations. However, initial shifts in Δ aligned most closely with the onset of the late Pleistocene bipolar temperature "seesaw" rather than CO2 increase, indicating unique limitations on glacial-age high-elevation plants may have existed due to both low temperatures and low CO2. Further development of system-specific faunal proxies can help to clarify this and other plant- and ecosystem-level responses to past environmental change.

  11. The early evolution of land plants, from fossils to genomics: a commentary on Lang (1937) 'On the plant-remains from the Downtonian of England and Wales'.

    PubMed

    Edwards, Dianne; Kenrick, Paul

    2015-04-19

    During the 1920s, the botanist W. H. Lang set out to collect and investigate some very unpromising fossils of uncertain affinity, which predated the known geological record of life on land. His discoveries led to a landmark publication in 1937, 'On the plant-remains from the Downtonian of England and Wales', in which he revealed a diversity of small fossil organisms of great simplicity that shed light on the nature of the earliest known land plants. These and subsequent discoveries have taken on new relevance as botanists seek to understand the plant genome and the early evolution of fundamental organ systems. Also, our developing knowledge of the composition of early land-based ecosystems and the interactions among their various components is contributing to our understanding of how life on land affects key Earth Systems (e.g. carbon cycle). The emerging paradigm is one of early life on land dominated by microbes, small bryophyte-like organisms and lichens. Collectively called cryptogamic covers, these are comparable with those that dominate certain ecosystems today. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.

  12. Cyclic terpenoids of contemporary resinous plant detritus and of fossil woods, ambers and coals

    USGS Publications Warehouse

    Simoneit, B.R.T.; Grimalt, J.O.; Wang, T.-G.; Cox, R.E.; Hatcher, P.G.; Nissenbaum, A.

    1986-01-01

    Cyclic terpenoids present in the solvent extractable material of fossil woods, ambers and brown coals have been analyzed. The sample series chosen consisted of wood remains preserved in Holocene to Jurassic sediments and a set of of ambers from the Philippines (copalite), Israel, Canada and Dominican Republic. The brown coals selected were from the Fortuna Garsdorf Mine and Miocene formations on Fiji. The fossil wood extracts contained dominant diterpenoid or sesquiterpenoid skeletons, and aromatized species were present at high concentrations, with a major amount of two-ring aromatic compounds. Tricyclic diterpenoids were the predominant compounds in the ambers. Aromatized derivatives were the major components, consisting of one or two aromatic ring species with the abietane and occasionally pimarane skeletons. The saturated structures were comprised primarily of the abietane and pimarane skeletons having from three to five carbon (C1, C2, etc.) substituents. Kaurane and phyllocladane isomers were present in only minor amounts. Bicyclic sesquiterpenoids as saturated and partial or fully aromatized forms were also common in these samples, but only traces of sesterterpenoids and triterpenoid derivatives were found. The brown coal extracts were composed of major amounts of one- and two-ring aromatized terpenoids, with a greater proportion of triterpenoid derivatives than in the case of the woods and ambers. This was especially noticeable for the German coal, where the triterpenoids were predominant. Open C-ring aromatized structures were also present in this coal. Steroid compounds were not detectable, but some hopanes were found as minor components in the German brown coal. An overview of the skeletal structure classes identified in each sample, as well as the general mass spectrometric characteristics of the unknown compounds are included in the present paper. It can be concluded from these structural distributions that aromatization is the main process for the

  13. Water impacts of CO2 emission performance standards for fossil fuel-fired power plants.

    PubMed

    Talati, Shuchi; Zhai, Haibo; Morgan, M Granger

    2014-10-21

    We employ an integrated systems modeling tool to assess the water impacts of the new source performance standards recently proposed by the U.S. Environmental Protection Agency for limiting CO2 emissions from coal- and gas-fired power plants. The implementation of amine-based carbon capture and storage (CCS) for 40% CO2 capture to meet the current proposal will increase plant water use by roughly 30% in supercritical pulverized coal-fired power plants. The specific amount of added water use varies with power plant and CCS designs. More stringent emission standards than the current proposal would require CO2 emission reductions for natural gas combined-cycle (NGCC) plants via CCS, which would also increase plant water use. When examined over a range of possible future emission standards from 1100 to 300 lb CO2/MWh gross, new baseload NGCC plants consume roughly 60-70% less water than coal-fired plants. A series of adaptation approaches to secure low-carbon energy production and improve the electric power industry's water management in the face of future policy constraints are discussed both quantitatively and qualitatively.

  14. Climate-vegetation modelling and fossil plant data suggest low atmospheric CO2 in the late Miocene

    NASA Astrophysics Data System (ADS)

    Forrest, M.; Eronen, J. T.; Utescher, T.; Knorr, G.; Stepanek, C.; Lohmann, G.; Hickler, T.

    2015-12-01

    There is an increasing need to understand the pre-Quaternary warm climates, how climate-vegetation interactions functioned in the past, and how we can use this information to understand the present. Here we report vegetation modelling results for the Late Miocene (11-7 Ma) to study the mechanisms of vegetation dynamics and the role of different forcing factors that influence the spatial patterns of vegetation coverage. One of the key uncertainties is the atmospheric concentration of CO2 during past climates. Estimates for the last 20 million years range from 280 to 500 ppm. We simulated Late Miocene vegetation using two plausible CO2 concentrations, 280 ppm CO2 and 450 ppm CO2, with a dynamic global vegetation model (LPJ-GUESS) driven by climate input from a coupled AOGCM (Atmosphere-Ocean General Circulation Model). The simulated vegetation was compared to existing plant fossil data for the whole Northern Hemisphere. For the comparison we developed a novel approach that uses information of the relative dominance of different plant functional types (PFTs) in the palaeobotanical data to provide a quantitative estimate of the agreement between the simulated and reconstructed vegetation. Based on this quantitative assessment we find that pre-industrial CO2 levels are largely consistent with the presence of seasonal temperate forests in Europe (suggested by fossil data) and open vegetation in North America (suggested by multiple lines of evidence). This suggests that during the Late Miocene the CO2 levels have been relatively low, or that other factors that are not included in the models maintained the seasonal temperate forests and open vegetation.

  15. Plant Hemoglobins: A Molecular Fossil Record for the Evolutin of Oxygen Transport

    SciTech Connect

    Hoy,J.; Robinson, H.; Trent, lll, J.; Kakar, S.; Smagghe, B.; Hargrove, M.

    2007-01-01

    The evolution of oxygen transport hemoglobins occurred on at least two independent occasions. The earliest event led to myoglobin and red blood cell hemoglobin in animals. In plants, oxygen transport 'leghemoglobins' evolved much more recently. In both events, pentacoordinate heme sites capable of inert oxygen transfer evolved from hexacoordinate hemoglobins that have unrelated functions. High sequence homology between hexacoordinate and pentacoordinate hemoglobins in plants has poised them for potential structural analysis leading to a molecular understanding of this important evolutionary event. However, the lack of a plant hexacoordinate hemoglobin structure in the exogenously ligand-bound form has prevented such comparison. Here we report the crystal structure of the cyanide-bound hexacoordinate hemoglobin from barley. This presents the first opportunity to examine conformational changes in plant hexacoordinate hemoglobins upon exogenous ligand binding, and reveals structural mechanisms for stabilizing the high-energy pentacoordinate heme conformation critical to the evolution of reversible oxygen binding hemoglobins.

  16. Plant hemoglobins: a molecular fossil record for the evolution of oxygen transport.

    PubMed

    Hoy, Julie A; Robinson, Howard; Trent, James T; Kakar, Smita; Smagghe, Benoit J; Hargrove, Mark S

    2007-08-03

    The evolution of oxygen transport hemoglobins occurred on at least two independent occasions. The earliest event led to myoglobin and red blood cell hemoglobin in animals. In plants, oxygen transport "leghemoglobins" evolved much more recently. In both events, pentacoordinate heme sites capable of inert oxygen transfer evolved from hexacoordinate hemoglobins that have unrelated functions. High sequence homology between hexacoordinate and pentacoordinate hemoglobins in plants has poised them for potential structural analysis leading to a molecular understanding of this important evolutionary event. However, the lack of a plant hexacoordinate hemoglobin structure in the exogenously ligand-bound form has prevented such comparison. Here we report the crystal structure of the cyanide-bound hexacoordinate hemoglobin from barley. This presents the first opportunity to examine conformational changes in plant hexacoordinate hemoglobins upon exogenous ligand binding, and reveals structural mechanisms for stabilizing the high-energy pentacoordinate heme conformation critical to the evolution of reversible oxygen binding hemoglobins.

  17. Some in situ fossil plants in Late Paleozoic rocks, eastern U. S. A

    SciTech Connect

    Cross, A.T. )

    1991-01-01

    Plants entombed in growth position are generally represented by standing stumps. Rarely, leaves or fronds may also represent plants buried in place. Stemps are most often seen in surface coal mine highwalls and highway cuts. Occasionally they are also found in association with sandstone cliffs. When present in coal-bearing sequences they are most often rooted in the top of the coal and may extend upward through several successive increments of sediments representing point-bar or overbank deposits in deltaic or fluvial depositional environments. Some standing logs in sandstones represent burial by washover fans or transgressive bars. Interpretation of the life environment of the plants and the successive environments in which the sediments that engulfed the plants were deposited demonstrated their paleoenvironment.

  18. Fossil plant stomata indicate decreasing atmospheric CO2 prior to the Eocene-Oligocene boundary

    NASA Astrophysics Data System (ADS)

    Steinthorsdottir, Margret; Porter, Amanda S.; Holohan, Aidan; Kunzmann, Lutz; Collinson, Margaret; McElwain, Jennifer C.

    2016-02-01

    A unique stratigraphic sequence of fossil leaves of Eotrigonobalanus furcinervis (extinct trees of the beech family, Fagaceae) from central Germany has been used to derive an atmospheric pCO2 record with multiple data points spanning the late middle to late Eocene, two sampling levels which may be earliest Oligocene, and two samples from later in the Oligocene. Using the inverse relationship between the density of stomata and pCO2, we show that pCO2 decreased continuously from the late middle to late Eocene, reaching a relatively stable low value before the end of the Eocene. Based on the subsequent records, pCO2 in parts of the Oligocene was similar to latest Eocene values. These results suggest that a decrease in pCO2 preceded the large shift in marine oxygen isotope records that characterizes the Eocene-Oligocene transition and that when a certain threshold of pCO2 change was crossed, the cumulative effects of this and other factors resulted in rapid temperature decline, ice build up on Antarctica and hence a change of climate mode.

  19. Fossil plant stomata indicate decreasing atmospheric CO2 prior to the Eocene-Oligocene boundary

    NASA Astrophysics Data System (ADS)

    Steinthorsdottir, M.; Porter, A. S.; Holohan, A.; Kunzmann, L.; Collinson, M.; McElwain, J. C.

    2015-10-01

    A unique stratigraphic sequence of fossil leaves of Eotrigonobalanus furcinervis (extinct trees of the beech family, Fagaceae) from central Germany has been used to derive an atmospheric pCO2 record with multiple data points spanning the late middle to late Eocene, two sampling levels which may be earliest Oligocene, and two samples from later in the Oligocene. Using the inverse relationship between the density of stomata and pCO2, we show that pCO2 decreased continuously from the late middle to late Eocene, reaching a relatively stable low value before the end of the Eocene. Based on the subsequent records, pCO2 in parts of the Oligocene was similar to latest Eocene values. These results show that a decrease in pCO2 preceded the large shift in marine oxygen isotope records that characterizes the Eocene-Oliogocene transition. This may be related to the "hysteresis effect" previously proposed - where a certain threshold of pCO2 change was crossed before the cumulative effects of this and other factors resulted in rapid temperature decline, ice build up on Antarctica and hence a change of climate mode.

  20. Reaction of oxygen with allene

    SciTech Connect

    Huang, Sheng-yu

    1988-07-01

    Elastic scattering studies carried out independently of the work related to the title forms the first section of the dissertation. The low-energy elastic scattering of He with Ar, Kr, Xe has been studied by molecular beam techniques. Two potential forms, exponential-spline-Morse-Morse-spline-van de Waals (ESMMSV) and Simon-Parr-Finlan-Dunham (SPFD), have been used to fit the measured differential cross section. Elastic scattering theory and experimental details are introduced. The reactive scattering of O(/sup 3/P) with allene has been studied using crossed molecular beams. Differing from the well known central-carbon-attack (CCA) mechanism in which the final products, carbon monoxide and ethylene, are obtained via a ring intermediate, a new mechanism, terminal-carbon-attack (TCA), has been observed. The production of O(/sup 3/P) atoms by radio frequency discharge is also introduced. To assist understanding of the experiments a multi-configuration self-consistent field (MCSCF) study of the reaction of O(/sup 3/P) with allene has been carried out. The key feature of the oxygen-allene potential energy surface for both CCA and TCA channels has been calculated with single-zeta (SZ), double-zeta (DZ), and double-zeta plus polarization (DZP) basis sets. Finally, an algorithm for optimizing the trial wavefunction in quantum Monte Carlo calculations has been developed. With the application of group theory, a symmetry-constrained optimization process can yield an improved trial wavefunction for the calculation of excited electronic state energies as well as the ground-state energy. Several applications are discussed. 145 refs.

  1. Paleovegetation changes recorded by n-alkyl lipids bound in macromolecules of plant fossils and kerogens from the Cretaceous sediments in Japan

    NASA Astrophysics Data System (ADS)

    Miyata, Y.; Sawada, K.; Nakamura, H.; Takashima, R.; Takahashi, M.

    2014-12-01

    Resistant macromolecules composing living plant tissues tend to be preserved through degradation and diagenesis, hence constituate major parts of sedimentary plant-derived organic matter (kerogen), and their monomer compositions vary widely among different plant taxa, organs and growth stages. Thus, analysis of such macromolecule may serve as new technique for paleobotanical evaluation distinctive from classical paleobotnical studies depends on morphological preservation of fossils. In the present study, we analyzed plant fossils and kerogens in sediments from the Cretaceous strata in Japan to examine chemotaxonomic characteristics of fossil macromolecules and to reconstruct paleovegetation change by kerogen analysis. The kerogens were separated from the powdered sediments of Cretaceous Yezo Group, Hokkaido, Japan. All kerogens have been confirmed to be mostly originated from land plant tissues by microscopic observation. Mummified angiosperm and gymnosperm fossil leaves were separated from carbonaceous sandstone of the Cretaceous Ashizawa Formation, Futaba Group. The kerogens and plant fossils were extracted with methanol and dichloromethane, and were subsequently refluxed under 110°C to remove free compounds completely. The residues are hydrolyzed by KOH/methanol under 110°C. These released compounds are analyzed by GC-MS. As main hydrolyzed products (ester-bound molecular units) from all kerogens, C10-C28 n-alkanoic acids and C10-C30 n-alkanols were detected. Recent studies on the hydrolysis products of plant tissues suggested the long chain (>C20) n-alkanols were predominantly abundant in deciduous broadleaved angiosperms. Correspondingly, the stratigraphic variation of the ratios of long chain (>C20) n-alkanols to fatty acids was concordant with the variation of angiosperm/gymnosperm ratios recorded by land plant-derived terpenoid biomarkers. In addition, we found that the long chain n-alkanols/fatty acids ratio in the angiosperm fossil leaf was

  2. "Fossil" Forecasting.

    ERIC Educational Resources Information Center

    Brody, Michael J.; deOnis, Ann

    2001-01-01

    Presents a density study in which students calculate the density of limestone substrate to determine if the specimen contains any fossils. Explains how to make fossils and addresses national standards. (YDS)

  3. Mutagenicity of diesel exhaust particles from two fossil and two plant oil fuels.

    PubMed

    Bünger, J; Müller, M M; Krahl, J; Baum, K; Weigel, A; Hallier, E; Schulz, T G

    2000-09-01

    Particulate matter of diesel engine exhaust from four different fuels was studied for content of polynuclear aromatic compounds and mutagenic effects. Two so-called biodiesel fuels, rapeseed oil methylesters (RME) and soybean oil methylesters (SME), were compared directly with two fossil diesel fuels with the normal (DF) and a low sulfur content (LS-DF). Diesel exhaust particles were sampled on filters from the diluted and cooled exhaust of a test engine at five different speeds and loads. Filters were weighed for total particulate matter, Soxhlet extracted with dichloromethane and the content of insoluble material determined. The soluble organic fraction was analysed for polynuclear aromatic compounds. Mutagenicity was determined using the Salmonella typhimurium/mammalian microsome assay with strains TA98 and TA100. Compared with DF, the exhaust particles of LS-DF, RME and SME contained less insoluble material, which consisted mainly of the carbon cores of diesel exhaust particles. The concentrations of individual polynuclear aromatic compounds varied widely among the different exhaust extracts, but total concentrations of the compounds were approximately double for DF and SME compared with LS-DF and RME. In TA98 significant increases in mutation rates were obtained for the soluble organic fractions of all fuels for engines running at full speed (load modes A and D), but for DF revertants were 2- to 10-fold more frequent as compared with LS-DF, RME and SME. Revertant frequencies for DF and partly for LS-DF were also elevated in TA100, while RME and SME gave no significant increase in mutations. The results indicate that diesel exhaust particles from RME, SME and LS-DF contain less black carbon and total polynuclear aromatic compounds and are significantly less mutagenic in comparison with DF. A high sulfur content of the fuel and high engine speeds (rated power) and loads are associated with an increase in mutagenicity of diesel exhaust particles.

  4. Fossil Explorers

    ERIC Educational Resources Information Center

    Moran, Sean; McLaughlin, Cheryl; MacFadden, Bruce; Jacobbe, Elizabeth; Poole, Michael

    2015-01-01

    Many young learners are fascinated with fossils, particularly charismatic forms such as dinosaurs and giant sharks. Fossils provide tangible, objective evidence of life that lived millions of years ago. They also provide a timescale of evolution not typically appreciated by young learners. Fossils and the science of paleontology can, therefore,…

  5. Marquee Fossils

    ERIC Educational Resources Information Center

    Clary, Renee; Wandersee, James

    2008-01-01

    Professors of an online graduate-level paleontology class developed the concept of marquee fossils--fossils that have one or more unique characteristics that capture the attention and direct observation of students. In the classroom, Marquee fossils integrate the geology, biology, and environmental science involved in the study of fossilized…

  6. Optimizing efficiency of zebra mussel monitoring at TVA power plants

    SciTech Connect

    Kerley, B.L.

    1995-06-01

    The Tennessee Valley Authority (TVA) began monitoring for zebra mussels in spring 1992 and first detected veligers entering plant intake at Shawnee, Allen and Cumberland Fossil Plans in summer 1993. Existing information indicated that densities of zebra mussel veligers at plant intakes did not always correspond to densities in critical pipe units; however, a more accurate predictive technique was unavailable. The two sites chosen for this project were Shawnee Fossil Plant on the Ohio River and Allen Fossil Plant on the Mississippi River. The project involved a coordinated series of experiments to determine how densities of zebra mussel veligers varied throughout the day, how veliger densities estimated outside the plants related to estimates at different internal locations, and how growth rate of adult zebra mussels compared using measurements taken inside and outside the plants and from the two different rivers. The data indicated no significant difference in veliger densities from samples collected at the intakes and samples collected inside the plants. There was also no significant difference in densities between samples collected inside the plants. There was also no significant difference in densities between samples taken at different times of the day. The data did indicate a significant difference in density estimates between samples collected on different days and between densities in the rivers compared to densities being drawn into the plant. The results will be used to assist plant staff in evaluating future data and in planning a more effective and cost efficient monitoring program.

  7. Water resources of Allen Parish

    USGS Publications Warehouse

    Prakken, Lawrence B.; Griffith, Jason M.; Fendick, Robert B.

    2012-01-01

    In 2005, approximately 29.2 million gallons per day (Mgal/d) of water were withdrawn in Allen Parish, Louisiana, including about 26.8 Mgal/d from groundwater sources and 2.45 Mgal/d from surface-water sources. Rice irrigation accounted for 74 percent (21.7 Mgal/d) of the total water withdrawn. Other categories of use included public supply, industrial, rural domestic, livestock, general irrigation, and aquaculture. Water-use data collected at 5-year intervals from 1960 to 2005 indicate water withdrawals in the parish were greatest in 1960 (119 Mgal/d) and 1980 (98.7 Mgal/d). The substantial decrease in surface-water use between 1960 and 1965 is primarily attributable to rice-irrigation withdrawals declining from 61.2 to 6.74 Mgal/d. This fact sheet summarizes information on the water resources of Allen Parish, La. Information on groundwater and surface-water availability, quality, development, use, and trends is based on previously published reports listed in the Selected References section.

  8. Cost and Quality Management: Making fossil power and plants more competitive: Phase 1

    SciTech Connect

    McQueen, R.S. . Center for Productivity and Mfg. Engineering)

    1992-05-01

    Cost and Quality Management theory is helping to make US corporations profitable again. Summarizing Phase 1 of a three-phase study, this report defines how Cost and Quality Management (also called Total Quality Management) relates to power production plants, the barriers standing in the way, and the concepts needed to overcome them. Major barriers include resistance to change, sparse efforts to grow employee initiative and self-esteem, a lack of understanding the importance of internal customers, and traditional management practices as represented by the top-to-bottom organization chart. Breakthrough concepts include a commitment to making and sustaining quality-based changes, realizing the potential of human assets, focusing on satisfying internal as well as external customers, and treating work as a process that crosses departments. The report ends by describing five other ongoing EPRI projects designed to help utility executives change from a traditional management style to Cost and Quality Management.

  9. Cost and Quality Management: Making fossil power and plants more competitive: Phase 1. Final report

    SciTech Connect

    McQueen, R.S.

    1992-05-01

    Cost and Quality Management theory is helping to make US corporations profitable again. Summarizing Phase 1 of a three-phase study, this report defines how Cost and Quality Management (also called Total Quality Management) relates to power production plants, the barriers standing in the way, and the concepts needed to overcome them. Major barriers include resistance to change, sparse efforts to grow employee initiative and self-esteem, a lack of understanding the importance of internal customers, and traditional management practices as represented by the top-to-bottom organization chart. Breakthrough concepts include a commitment to making and sustaining quality-based changes, realizing the potential of human assets, focusing on satisfying internal as well as external customers, and treating work as a process that crosses departments. The report ends by describing five other ongoing EPRI projects designed to help utility executives change from a traditional management style to Cost and Quality Management.

  10. High-Resolution pCO2 Record for the Cenomanian-Turonian OAE2 based on Fossil Plant Cuticle

    NASA Astrophysics Data System (ADS)

    Barclay, R. S.; Sageman, B. B.; McElwain, J. C.

    2008-12-01

    The Cenomanian-Turonian oceanic anoxic event 2 (OAE2) represents a major perturbation to the ocean- atmosphere-terrestrial system that lasted at least 600 ka. Marine extinction associated with OAE2 is thought to have occurred due to global marine anoxia, and increased primary production is the likely driver. However, the causal factors leading to increased production have remained poorly resolved. Recent research indicates that a pulse of submarine volcanism occurred in association with OAE2, and it has been suggested that this event led to overturn of the stratified ocean, possibly bringing P-rich deep waters to the surface. 208/204Pbinitial ratios taken from the Bonarelli horizon suggest that CO2 expelled by the volcanic event may have come from the Caribbean LIP. This is supported by a rapid negative shift in both 186/187Os and 87/86Sr isotopes just prior to OAE2, suggesting a marine source for the CO2 pulse. Some prior studies suggested that OAE2 resulted in a major drawdown of high ambient pCO2 levels. Only recently has a volcanic-sourced CO2 pulse been suggested for the event and its implications have yet to be fully explored. Two previous studies attempted to reconstruct pCO2 levels through OAE2 using geochemical proxy methods. Both studies show a decline in pCO2 at the onset of the δ13C excursion, but with decreases ranging from 140 to at least 400ppmV. Since neither study extended analyses to the interval preceding onset of the δ13C excursion it is difficult to assess the longer term trend. In addition, marine-based proxy methods contain large uncertainties that may be avoided in a non-marine proxy of pCO2, such as the stomatal frequency record of fossil plant cuticles. The stomatal based paleo-CO2 proxy relies on a genetically controlled inverse relationship between pCO2 and stomatal frequency in terrestrial plant leaves. Abundant plant cuticle is preserved in the paralic sections of the Dakota SS in SW Utah, which has been correlated to the Cenomanian

  11. Novel Dual-Functional Membrane for Controlling Carbon Dioxide Emissions from Fossil Fuel Power Plants

    SciTech Connect

    C. Brinker; George Xomeritakis; C.-Y. Tsai; Ying-Bing Jiang

    2009-04-30

    CO{sub 2} captured from coal-fired power plants represents three-quarters of the total cost of an entire carbon sequestration process. Conventional amine absorption or cryogenic separation requires high capital investment and is very energy intensive. Our novel membrane process is energy efficient with great potential for economical CO{sub 2} capture. Three classes of microporous sol-gel derived silica-based membranes were developed for selective CO{sub 2} removal under simulated flue gas conditions (SFG), e.g. feed of 10% vol. CO{sub 22} in N{sub 2}, 1 atm total pressure, T = 50-60 C, RH>50%, SO2>10 ppm. A novel class of amine-functional microporous silica membranes was prepared using an amine-derivatized alkoxysilane precursor, exhibiting enhanced (>70) CO{sub 2}:N{sub 2} selectivity in the presence of H{sub 2}O vapor, but its CO{sub 2} permeance was lagging (<1 MPU). Pure siliceous membranes showed higher CO{sub 2} permeance (1.5-2 MPU) but subsequent densification occurred under prolonged SFG conditions. We incorporated NiO in the microporous network up to a loading of Ni:Si = 0.2 to retard densification and achieved CO2 permeance of 0.5 MPU and CO{sub 2}:N{sub 2} selectivity of 50 after 163 h exposure to SFG conditions. However, CO{sub 2} permeance should reach greater than 2.0 MPU in order to achieve the cost of electricity (COE) goal set by DOE. We introduced the atomic layer deposition (ALD), a molecular deposition technique that substantially reduces membrane thickness with intent to improve permeance and selectivity. The deposition technique also allows the incorporation of Ni or Ag cations by proper selection of metallorganic precursors. In addition, preliminary economic analysis provides a sensitivity study on the performance and cost of the proposed membranes for CO{sub 2} capture. Significant progress has been made toward the practical applications for CO{sub 2} capture. (1 MPU = 1.0 cm{sup 3}(STP){center_dot}cm-2{center_dot}min-1{center_dot}atm-1)

  12. Fossil Fuels.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with fossil fuels. Some topics covered are historic facts, development of fuels, history of oil production, current and future trends of the oil industry, refining fossil fuels, and environmental problems. Material in each unit may…

  13. Ediacara Fossils

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Now, a research team from Virginia Tech and Nanjing Institute of Geology and Paleontology has discovered uniquely well-preserved fossil forms from 550-million-year-old rocks of the Ediacaran Period. The research appears in the Proceedings of the National Academy of Sciences. The discovery of these unusually preserved fossils reveals unprecedented…

  14. Fate of As, Se, and Hg in a Passive Integrated System for Treatment of Fossil Plant Wastewater

    SciTech Connect

    Terry Yost; Paul Pier; Gregory Brodie

    2007-12-31

    TVA is collaborating with EPRI and DOE to demonstrate a passive treatment system for removing SCR-derived ammonia and trace elements from a coal-fired power plant wastewater stream. The components of the integrated system consist of trickling filters for ammonia oxidation, reaction cells containing zero-valent iron (ZVI) for trace contaminant removal, a settling basin for storage of iron hydroxide floc, and anaerobic vertical-flow wetlands for biological denitrification. The passive integrated treatment system will treat up to 0.25 million gallons per day (gpd) of flue gas desulfurization (FGD) pond effluent, with a configuration requiring only gravity flow to obviate the need for pumps. The design of the system will enable a comparative evaluation of two parallel treatment trains, with and without the ZVI extraction trench and settling/oxidation basin components. One of the main objectives is to gain a better understanding of the chemical transformations that species of trace elements such as arsenic, selenium, and mercury undergo as they are treated in passive treatment system components with differing environmental conditions. This progress report details the design criteria for the passive integrated system for treating fossil power plant wastewater as well as performance results from the first several months of operation. Engineering work on the project has been completed, and construction took place during the summer of 2005. Monitoring of the passive treatment system was initiated in October 2005 and continued until May 18 2006. The results to date indicate that the treatment system is effective in reducing levels of nitrogen compounds and trace metals. Concentrations of both ammonia and trace metals were lower than expected in the influent FGD water, and additions to increase these concentrations will be done in the future to further test the removal efficiency of the treatment system. In May 2006, the wetland cells were drained of FGD water, refilled with

  15. Miocene fossil plants from Bukpyeong Formation of Bukpyeong Basin in Donghae City, Gangwon-do Province, Korea and their palaeoenvironmental implications

    NASA Astrophysics Data System (ADS)

    Jeong, Eun Kyoung; Kim, Hyun Joo; Uemura, Kazuhiko; Kim, Kyungsik

    2016-04-01

    The Tertiary sedimentary basins are distributed along the eastern coast of Korean Peninsula. The northernmost Bukpyeong Basin is located in Donghae City, Gangwon-do Province, Korea. The Bukpyeong Basin consists of Bukpyeong Formation and Dogyeongri Conglomerate in ascending order. The geologic age of Bukpyeong Formation has been suggested as from Early Miocene to Pliocene, In particular, Lee & Jacobs (2010) suggested the age of the Bukpyeong Formation as late Early Miocene to early Middle Miocene based on the fossils of rodent teeth. Sedimentary environment has been thought as mainly fresh water lake and/or swamp partly influenced by marine water. Lately, new outcrops of Bukpyeong Formation were exposed during the road construction and abundant fossil plants were yielded from the newly exposed outcrops. As a result of palaeobotanical studies 47 genera of 23 families have been found. This fossil plant assemblage is composed of gymnosperms and dicotyledons. Gymnosperms were Pinaceae (e.g., Pinus, Tsuga), Sciadopityaceae (e.g., Sciadopitys) and Cupressaceae with well-preserved Metasequoia cones. Dicotyledons were deciduous trees such as Betulaceae (e.g., Alnus, Carpinus) and Sapindaceae (e.g., Acer, Aesculus, Sapindus), and evergreen trees such as evergreen Fagaceae (e.g., Castanopsis, Cyclobalanopsis, Pasania) and Lauraceae (e.g., Cinnamomum, Machilus). In addition, fresh water plants such as Hemitrapa (Lytraceae) and Ceratophyllum (Ceratophyllaceae) were also found. The fossil plant assemblage of the Bukpyeong Formation supported the freshwater environment implied by previous studies. It can be suggested that the palaeoflora of Bukpyeong Formation was oak-laurel forest with broad-leaved evergreen and deciduous trees accompanying commonly by conifers of Pinaceae and Cupressaceae under warm-temperate climate.

  16. Van Allen Discovery Most Important

    NASA Technical Reports Server (NTRS)

    Jastrow, R.

    1959-01-01

    The first step toward the exploration of space occurred approximately 22 months ago as a part of the International Geophysical Year. In the short interval since October, 1957, the new tools of research, the satellite and the space rocket, have produced two unexpected results of fundamental scientific importance. First, instruments placed in the Explorer satellites by James A. Van Allen have revealed the existence of layers of energetic particles in the outer atmosphere. This discovery constitutes the most significant research achievement of the IGY satellite program. The layers may provide the explanation for the aurora and other geophysical phenomena, and they will also influence the design of vehicles for manned space flight, whose occupants must be shielded against their harmful biological effects. Second, the shape of the earth has been determined very accurately with the aid of data from the first Vanguard. As a result of this investigation, we have found that our planet tends toward the shape of a pear, with its stem at the North Pole. This discovery may produce major changes in our ideas on the interior structure of the earth.

  17. Phosphine Catalysis of Allenes with Electrophiles

    PubMed Central

    Wang, Zhiming; Xu, Xingzhu; Kwon, Ohyun

    2014-01-01

    Nucleophilic phosphine catalysis of allenes with electrophiles is one of the most powerful and straightforward synthetic strategies for the generation of highly functionalized carbocycle or heterocycle structural motifs, which are present in a wide range of bioactive natural products and medicinally important substances. The reaction topologies can be controlled through judicious choice of the phosphine catalyst and the structural variations of starting materials. This Tutorial Review presents selected examples of nucleophilic phosphine catalysis using allenes and electrophiles. PMID:24663290

  18. Plant materials and amendments for controlling wind and water erosion on a fly ash disposal area: TVA Colbert Fossil Plant, Alabama

    SciTech Connect

    Maddox, J.J.; Behel, D.; Soileau, J.M.; Kelsoe, J.

    1996-12-31

    Fly ash disposal sites adjacent to fossil fueled generating plants are subject to wind and water erosion which increases the operation and maintenance costs. Gullies and unstable areas in the disposal sites require expensive leveling and filling practices. Test evaluated both warm- and cool-season cover crops established by either sod or seed. Amendments to the ash consisted of composted poultry litter (CPL), soil, soil+CPL, fertilizer and beneficial soil microbes including mycorrhizal fungi. Turf sods (419 Bermuda, Emerald zoysia, and Raleigh St. Augustine) were compared in greenhouse and field studies. Six legumes and 12 grass species were tested in the greenhouse as seeded cover crops using similar amendments and raw poultry litter (PL). Legumes grew better with CPL and Boil amendments and grasses grew better on PL and soil amendments possibly due to differences in N requirements and N supply. Cool season crops generally grew faster than warm season species in the greenhouse tests. Amendments should be mixed with the FA to ameliorate the effects of boron and salt toxicity and to increase the water holding capacity. Bermuda sod grew faster than either St, Augustine or Emerald zoysia, but requires more water. A microbial amendment increased dry matter yields of bermuda sod 2 to 3 times after 40 to 60 days over unamended controls. Microbial amendments may be justified on an economic and sustainable basis. A field study is assessing the environmental and cultural requirements to grow a cover crop on an annual basis.

  19. Electrophilic addition and cyclization reactions of allenes.

    PubMed

    Ma, Shengming

    2009-10-20

    Modern organic synthesis depends on the development of highly selective methods for the efficient construction of potentially useful target molecules. A primary goal in our laboratory is the discovery of new reactions that convert readily available starting materials to complex products with complete control of regio- and stereoselectivity. Allenes are one underused moiety in organic synthesis, because these groups are often thought to be highly reactive. However, many compounds containing the allene group, including natural products and pharmaceuticals, are fairly stable. The chemistry of allenes has been shown to have significant potential in organic synthesis. Electrophilic additions to allenes have often been considered to be synthetically less attractive due to the lack of efficient control of the regio- and stereoselectivity. However, this Account describes electrophilic reactions of allenes with defined regio- and stereoselectivity developed in our laboratory. Many substituted allenes are readily available from propargylic alcohols. Our work has involved an exploration of the reactions of these allenes with many different electrophiles: the E- or Z-halo- or seleno-hydroxylations of allenyl sulfoxides, sulfones, phosphine oxides, carboxylates, sulfides or selenides, butenolides, and arenes, and the halo- or selenolactonization reactions of allenoic acids and allenoates. These reactions have produced a host of new compounds such as stereodefined allylic alcohols, ethers, amides, thiiranes, and lactones. In all these reactions, water acts as a reactant and plays an important role in determining the reaction pathway and the stereoselectivity. The differing electronic properties of the two C=C bonds in these allenes determine the regioselectivity of these reactions. Through mechanistic studies of chirality transfer, isolation and reactivity of cyclic intermediates, (18)O-labeling, and substituent effects, we discovered that the E-stereoselectivity of some

  20. Fossil Horses

    NASA Astrophysics Data System (ADS)

    MacFadden, Bruce J.

    1994-06-01

    The family Equidae have an extensive fossil record spanning the past 58 million years, and the evolution of the horse has frequently been used as a classic example of long-term evolution. In recent years, however, there have been many important discoveries of fossil horses, and these, in conjunction with such new methods as cladistics, and techniques such as precise geochronology, have allowed us to achieve a much greater understanding of the evolution and biology of this important group. This book synthesizes the large body of data and research relevant to an understanding of fossil horses from several disciplines including biology, geology and paleontology. Using horses as the central theme, the author weaves together in the text such topics as modern geochronology, paleobiogeography, climate change, evolution and extinction, functional morphology, and population biology during the Cenozoic period. This book will be exciting reading for researchers and graduate students in vertebrate paleontology, evolution, and zoology.

  1. Δ(14)CO2 from dark respiration in plants and its impact on the estimation of atmospheric fossil fuel CO2.

    PubMed

    Xiong, Xiaohu; Zhou, Weijian; Cheng, Peng; Wu, Shugang; Niu, Zhenchuan; Du, Hua; Lu, Xuefeng; Fu, Yunchong; Burr, George S

    2017-04-01

    Radiocarbon ((14)C) has been widely used for quantification of fossil fuel CO2 (CO2ff) in the atmosphere and for ecosystem source partitioning studies. The strength of the technique lies in the intrinsic differences between the (14)C signature of fossil fuels and other sources. In past studies, the (14)C content of CO2 derived from plants has been equated with the (14)C content of the atmosphere. Carbon isotopic fractionation mechanisms vary among plants however, and experimental study on fractionation associated with dark respiration is lacking. Here we present accelerator mass spectrometry (AMS) radiocarbon results of CO2 respired from 21 plants using a lab-incubation method and associated bulk organic matter. From the respired CO2 we determine Δ(14)Cres values, and from the bulk organic matter we determine Δ(14)Cbom values. A significant difference between Δ(14)Cres and Δ(14)Cbom (P < 0.01) was observed for all investigated plants, ranging from -42.3‰ to 10.1‰. The results show that Δ(14)Cres values are in agreement with mean atmospheric Δ(14)CO2 for several days leading up to the sampling date, but are significantly different from corresponding bulk organic Δ(14)C values. We find that although dark respiration is unlikely to significantly influence the estimation of CO2ff, an additional bias associated with the respiration rate during a plant's growth period should be considered when using Δ(14)C in plants to quantify atmospheric CO2ff.

  2. Plant for preparing and hydrogenating fossil fuels to prepare products low in sulfur content, and employment of these products for combined generation of the electric current and gas

    SciTech Connect

    Schuster, E.; Knizia, K.

    1986-07-01

    A plant is described for producing solid and gaseous desulfurizing fossil fuels for use in a gas turbine power plant and a steam power plant for electric power generation. The plant consists of operatively interconnected components including sequentially in combination: crusher means for crushing the fuel to a particle size not to exceed 0.1 mm., a vapor separator, means for supplying hot, substantially inert, flue gas to the crusher means to convey the crushed fuel to the separator with simultaneous evaporation of moisture therefrom, a preoxidation station, means to convey the fuel to the preoxidation station, means to convey the fuel to the preoxidation station, means to supply heated air to the preoxidation station to oxidize the fuel, a separator for separating the air from the oxidized fuel, a reaction chamber station and means to supply the chamber with the pre-oxidized fuel and in which chamber the gas content of the fuel is adjusted, means for supplying steam to the reaction chamber station to hydrolyze the fuel, a separator station past the reaction chamber station to separate the oxidized fuel from gas, an additional gas driven conveyor and distributor means for distributing the solid product from the reaction chamber station to the steam generator plant, means for extensively desulfurized gas leaving the separator from the reaction chamber station, distributor means for distributing the desulfurized gas to the gas turbine power plant and at least a portion of the gas to the steam generator plant.

  3. Cycads: Fossil evidence of late paleozoic origin

    USGS Publications Warehouse

    Mamay, S.H.

    1969-01-01

    Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of the Permian fossils toward evolution of the angiosperm carpel are considered.

  4. Cycads: fossil evidence of late paleozoic origin.

    PubMed

    Mamay, S H

    1969-04-18

    Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications of the Permian fossils toward evolution of the angiosperm carpel are considered.

  5. Allen Auditorium attic looking from southeast corner. Wine barrels with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Allen Auditorium attic looking from southeast corner. Wine barrels with scrap used for counterweight material for lift up walls no longer in use - Sheldon Jackson College, Richard H. Allen Memorial Hall, Lincoln Street, Sitka, Sitka Borough, AK

  6. Reconstructing Middle Eocene Climate and Atmospheric Carbon Dioxide Concentration: Application of a mechanistic theoretical approach to fossil plants from the Messel Pit (Germany)

    NASA Astrophysics Data System (ADS)

    Grein, M.; Roth-Nebelsick, A.; Wilde, V.; Konrad, W.; Utescher, T.

    2009-12-01

    It is assumed that changes in atmospheric CO2 concentrations (from now on expressed as Ca) strongly influenced the development of global temperatures during parts of the Cenozoic. Thus, detailed knowledge of ancient Ca and its variations is of utmost importance for exploring the coupling of atmospheric CO2 and global climate change. Numerous techniques (such as carbon and boron isotopes) were applied in order to obtain Ca, with varying and sometimes even conflicting results. Stomatal density (number of stomata per leaf area) represents another promising proxy for the calculation of ancient Ca since many plants reduce the number of stomata (pores on the leaf surface used for gas exchange) under increasing Ca. As a reason it is assumed that plants try to adjust stomatal conductance in order to optimize their gas exchange (which means maximal assimilation at minimal transpiration). The common technique for calculating Ca from fossil stomatal frequency is to create empirical transfer functions of living plants derived from herbar material or greenhouse experiments. In the presented project, Ca of the Middle Eocene is calculated by applying a different approach which utilizes a mechanistic-theoretical calibration. It couples the processes of a) C3-photosynthesis, b) diffusion and c) transpiration with palaeoclimatic and leaf-anatomical data. The model also includes an optimisation principle supported by ecophysiological data. According to this optimisation principle, plants adjust their stomatal conductance in such a way that photosynthesis rates are constrained by optimal water use (transpiration). This model was applied in the present study to fossil plants from the Messel Pit near Darmstadt (Germany). In order to reconstruct Ca by using fossil plant taxa from Messel, numerous parameters which represent model input have to be estimated from measurements of living representatives. Furthermore, since climate parameters are also required by the model, quantitative

  7. William G. Allen: On "Orators and Oratory."

    ERIC Educational Resources Information Center

    Calloway-Thomas, Carolyn

    1988-01-01

    William G. Allen was an African-American professor at Central College, McGrawville, New York. His lecture, "Orators and Oratory," delivered on June 22, 1852, is the earliest recorded study by an American Black on the ancient art of oratory. The text of the lecture is provided. (BJV)

  8. Revision of the Cretaceous fossil plant-assemblage from Gardeshwar (Gujarat, India): A conifer dominated floral association from an Upper Gondwana sequence on the West Coast of India

    NASA Astrophysics Data System (ADS)

    Jana, Brajendra Nath; King, Sarah C.; Hilton, Jason

    2013-09-01

    A small but diverse fossil plant assemblage from Gardeshwar in Gujarat Province of western India is reinvestigated, based on analysis of recently collected specimens that represent previously unrecognised taxa in combination with a critical review of previously reported taxa from the site. The assemblage is dominated by conifers including Brachyphyllum Brongniart, Elatocladus Halle, Pagiophyllum Heer, the cone Conites Sternberg, and ovulate scales of an araucarian conifer. Other plant groups are rare but include notable occurrences of the pteridophytes Lycopodites Lindley and Hutton and Gleichenia Smith, and the seed fern Sphenopteris (Brongniart) Sternberg. This assemblage is important as it represents the only datable fossils available from the Gardeshwar Formation and from the information presented we conclude it belongs to the Lower Cretaceous Allocladus-Brachyphyllum-Pagiophyllum floral biozone. The Gardeshwar assemblage association is unusual as it lacks the distinctive genus Allocladus but includes other taxa more typical of the Lower Cretaceous fern-dominated Weichselia-Onychiopsis-Gleichenia floral biozone, and may represent a transitional assemblage with characters of both biozones. However, this investigation highlights the lack of detailed stratigraphic analyses on the Lower Cretaceous sedimentary sequences of the west coast of India from which it remains uncertain if these two ‘biozones' are of different ages or whether they represent stratigraphically contemporaneous but ecologically distinct environments.

  9. Fossil plants indicate that the most significant decrease in atmospheric CO2 happened prior to the Eocene-Oligocene boundary

    NASA Astrophysics Data System (ADS)

    Steinthorsdottir, Margret; Porter, Amanda; Holohan, Aidan; Kunzmann, Lutz; Collinson, Margaret; McElwain, Jennifer

    2016-04-01

    A unique stratigraphic sequence of fossil leaves of Eotrigonobalanus furcinervis (extinct trees of the beech family, Fagaceae) from central Germany was utilized to derive an atmospheric pCO2 record with multiple data points spanning the late middle to late Eocene, two sampling levels which may be earliest Oligocene, and two samples from later in the Oligocene. Using the stomatal proxy, which relies on the inverse relationship between pCO2 and leaf stomatal density, we show that a ~40% decrease in pCO2 preceded the large shift in marine oxygen isotope records that characterizes the Eocene-Oliogocene climate transition. The results endorse the theory that pCO2 drawdown was the main forcer of the Eocene-Oligocene climate change, and a 'tipping point' was reached in the latest Eocene, triggering the plunge of the Earth System into icehouse conditions.

  10. H. Julian Allen with Blunt Body Theory

    NASA Technical Reports Server (NTRS)

    1957-01-01

    H. Julian Allen is best known for his 'Blunt Body Theory' of aerodynamics, a design technique for alleviating the severe re-entry heating problem which was then delaying the development of ballistic missiles. His findings revolutionized the fundamental design of ballistic missle re-entry shapes. Subsequently, applied research led to applications of the 'blunt' shape to ballistic missles and spacecraft which were intended to re-enter the Earth's atmosphere. This application led to the design of ablative heat shields that protected the Mercury, Gemini and Apollo astronauts as their space capsules re- entered the Earth's atmosphere. 'Harvey' Allen as he was called by most, was not only a brilliant scientist and aeronautical engineer but was also admired for his kindness, thoughtfulness and sense of humor. Among his many other accomplishments, Harvey Allen served as Center Director of the NASA Ames Research Center from 1965 to 1969. He died of a heart attack on January 29, 1977 at the age of 66.

  11. Bioaccumulation of metals in three freshwater mussel species exposed in situ during and after dredging at a coal ash spill site (Tennessee Valley Authority Kingston Fossil Plant).

    PubMed

    Otter, Ryan R; McKinney, David; Brown, Bobby; Lainer, Susan; Monroe, William; Hubbs, Don; Read, Bob

    2015-06-01

    On December 22, 2008, a dike containing coal fly ash at the Tennessee Valley Authority Kingston Fossil Plant (TN, USA) failed, and within months, dredging operations began to remove ash-contaminated sediments. The purpose of this study was to investigate differences in the bioaccumulation of metals in three mussel species during and after dredging operations. Mussels were caged for approximately 1 year during dredging and after, and then mussel condition index values and As, Cd, Cr, Pb, Ni, Se, Hg, U, Fe, Mg, Al, Sb, Ba, Be, Co, Cu, Mn, Mo, Ag, Sr, Tl, V, and Zn concentrations in soft tissue were determined via inductively coupled plasma-mass spectrometery. Overall, the differences observed in metal bioaccumulation and mussel health suggest that mussels in the immediate downstream area of the dredging site may have been impacted, as evidenced by a significant decrease in mussel condition index values, but that this impact did not result in increased tissue concentrations of metals.

  12. A new method to determine the ratio of electricity production from fossil and biogenic sources in waste-to-Energy plants.

    PubMed

    Fellner, Johann; Cencic, Oliver; Rechberger, Helmut

    2007-04-01

    New directives of the European Union require operators of waste-to-energy (WTE) plants to report the amount of electricity that is produced from renewable sources in the waste feed. Until now, the standard method to determine the portion of renewable electricity is sorting the wastes into defined fractions of fossil organic and biogenic waste components and determining the lower heating value of these fractions. Out of it the amount of electricity production from renewables is calculated. This practice is labor and cost intensive. Therefore, it is usually carried out once a year which provides only a snapshot analysis of limited significance. This paper proposes a method to calculate the portion of electricity produced from renewable materials in waste continuously by solving a set of equations. All data required are either available from literature or from operating data routinely measured in WTE plants. The advantages are statistically derived uncertainty of the result, temporal resolution of the result down to daily mean values, low implementation efforts, and virtually no operational costs. An example of the implementation of the method to a 60 000 tons per year WTE plant is given.

  13. The early evolution of land plants, from fossils to genomics: a commentary on Lang (1937) ‘On the plant-remains from the Downtonian of England and Wales'

    PubMed Central

    Edwards, Dianne; Kenrick, Paul

    2015-01-01

    During the 1920s, the botanist W. H. Lang set out to collect and investigate some very unpromising fossils of uncertain affinity, which predated the known geological record of life on land. His discoveries led to a landmark publication in 1937, ‘On the plant-remains from the Downtonian of England and Wales’, in which he revealed a diversity of small fossil organisms of great simplicity that shed light on the nature of the earliest known land plants. These and subsequent discoveries have taken on new relevance as botanists seek to understand the plant genome and the early evolution of fundamental organ systems. Also, our developing knowledge of the composition of early land-based ecosystems and the interactions among their various components is contributing to our understanding of how life on land affects key Earth Systems (e.g. carbon cycle). The emerging paradigm is one of early life on land dominated by microbes, small bryophyte-like organisms and lichens. Collectively called cryptogamic covers, these are comparable with those that dominate certain ecosystems today. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750238

  14. A research needs assessment for the capture, utilization and disposal of carbon dioxide from fossil fuel-fired power plants. Volume 1, Executive summary: Final report

    SciTech Connect

    Not Available

    1993-07-01

    This study identifies and assesses system approaches in order to prioritize research needs for the capture and non-atmospheric sequestering of a significant portion of the carbon dioxide (CO{sub 2}) emitted from fossil fuel-fired electric power plants (US power plants presently produce about 7% of the world`s CO{sub 2} emissions). The study considers capture technologies applicable either to existing plants or to those that optimistically might be demonstrated on a commercial scale over the next twenty years. Specific conclusions are as follows: (1) To implement CO{sub 2} capture and sequestration on a national scale will decrease power plant net efficiencies and significantly increase the cost of electricity. To make responsible societal decisions, accurate and consistent economic and environmental analysis of all alternatives for atmospheric CO{sub 2} mitigation are required. (2) Commercial CO{sub 2} capture technology, though expensive and energy intensive, exists today. (3) The most promising approach to more economical CO{sub 2} capture is to develop power plant systems that facilitate efficient CO{sub 2} capture. (4) While CO{sub 2} disposal in depleted oil and gas reservoirs is feasible today, the ability to dispose of large quantities Of CO{sub 2} is highly uncertain because of both technical and institutional issues. Disposal into the deep ocean or confined aquifers offers the potential for large quantity disposal, but there are technical, safety, liability, and environmental issues to resolve. Therefore, the highest priority research should focus on establishing the feasibility of large scale disposal options.

  15. Are the oldest 'fossils', fossils

    NASA Technical Reports Server (NTRS)

    Schopf, J. W.

    1976-01-01

    A comparative statistical study has been carried out on populations of modern algae, Precambrian algal microfossils, the 'organized elements' of the Orgueil carbonaceous meteorite, and the oldest microfossil-like objects now known (spheroidal bodies from the Fig Tree and Onverwacht Groups of the Swaziland Supergroup, South Africa). The distribution patterns exhibited by the more than 3000 m.y.-old Swaziland microstructures bear considerable resemblance to those of the abiotic 'organized elements' but differ rather markedly from those exhibited by younger, assuredly biogenic, populations. Based on these comparisons, it is concluded that the Swaziland spheroids could be, at least in part, of nonbiologic origin; these oldest known fossil-like microstructures should not be regarded as constituting firm evidence of Archean life.

  16. Allenes and computational chemistry: from bonding situations to reaction mechanisms.

    PubMed

    Soriano, Elena; Fernández, Israel

    2014-05-07

    The present review is focused on the application of computational/theoretical methods to the wide and rich chemistry of allenes. Special emphasis is made on the interplay and synergy between experimental and computational methodologies, rather than on recent developments in methods and algorithms. Therefore, this review covers the state-of-the-art applications of computational chemistry to understand and rationalize the bonding situation and vast reactivity of allenes. Thus, the contents of this review span from the most fundamental studies on the equilibrium structure and chirality of allenes to recent advances in the study of complex reaction mechanisms involving allene derivatives in organic and organometallic chemistry.

  17. A research needs assessment for the capture, utilization and disposal of carbon dioxide from fossil fuel-fired power plants. Volume 2, Topical reports: Final report

    SciTech Connect

    Not Available

    1993-07-01

    This study, identifies and assesses system approaches in order to prioritize research needs for the capture and non-atmospheric sequestering of a significant portion of the carbon dioxide (CO{sub 2}) emitted from fossil fuel-fired electric power plants (US power plants presently produce about 7% of the world`s CO{sub 2} emissions). The study considers capture technologies applicable either to existing plants or to those that optimistically might be demonstrated on a commercial scale over the next twenty years. The research needs that have high priority in establishing the technical, environmental, and economic feasibility of large-scale capture and disposal of CO{sub 2} from electric power plants are:(1) survey and assess the capacity, cost, and location of potential depleted gas and oil wells that are suitable CO{sub 2} repositories (with the cooperation of the oil and gas industry); (2) conduct research on the feasibility of ocean disposal, with objectives of determining the cost, residence time, and environmental effects for different methods of CO{sub 2} injection; (3) perform an in-depth survey of knowledge concerning the feasibility of using deep, confined aquifers for disposal and, if feasible, identify potential disposal locations (with the cooperation of the oil and gas industry); (4) evaluate, on a common basis, system and design alternatives for integration of CO{sub 2} capture systems with emerging and advanced technologies for power generation; and prepare a conceptual design, an analysis of barrier issues, and a preliminary cost estimate for pipeline networks necessary to transport a significant portion of the CO{sub 2} to potentially feasible disposal locations.

  18. A Complete Fossil-Calibrated Phylogeny of Seed Plant Families as a Tool for Comparative Analyses: Testing the ‘Time for Speciation’ Hypothesis

    PubMed Central

    Harris, Liam W.; Davies, T. Jonathan

    2016-01-01

    Explaining the uneven distribution of species richness across the branches of the tree of life has been a major challenge for evolutionary biologists. Advances in phylogenetic reconstruction, allowing the generation of large, well-sampled, phylogenetic trees have provided an opportunity to contrast competing hypotheses. Here, we present a new time-calibrated phylogeny of seed plant families using Bayesian methods and 26 fossil calibrations. While there are various published phylogenetic trees for plants which have a greater density of species sampling, we are still a long way from generating a complete phylogeny for all ~300,000+ plants. Our phylogeny samples all seed plant families and is a useful tool for comparative analyses. We use this new phylogenetic hypothesis to contrast two alternative explanations for differences in species richness among higher taxa: time for speciation versus ecological limits. We calculated net diversification rate for each clade in the phylogeny and assessed the relationship between clade age and species richness. We then fit models of speciation and extinction to individual branches in the tree to identify major rate-shifts. Our data suggest that the majority of lineages are diversifying very slowly while a few lineages, distributed throughout the tree, are diversifying rapidly. Diversification is unrelated to clade age, no matter the age range of the clades being examined, contrary to both the assumption of an unbounded lineage increase through time, and the paradigm of fixed ecological limits. These findings are consistent with the idea that ecology plays a role in diversification, but rather than imposing a fixed limit, it may have variable effects on per lineage diversification rates through time. PMID:27706173

  19. Will My Fossil Float?

    ERIC Educational Resources Information Center

    Riesser, Sharon; Airey, Linda

    1993-01-01

    Explains how young students can be introduced to fossils. Suggests books to read and science activities including "Fossils to Eat" where students make fossils from peanut butter, honey, and powdered milk. (PR)

  20. Prediction of atmospheric δ13CO2 using fossil plant tissues

    SciTech Connect

    A. Hope Jahren; Arens, Nan Crystal; Harbeson, Stephanie A.

    2008-06-30

    To summarize the content: we presented the results of laboratory experiments designed to quantify the relationship between plant tissue δ13C and δ13CO2 values under varying environmental conditions, including differential pCO2 ranging from 1 to 3 times today’s levels. As predicted, plants grown under elevated pCO2 showed increased average biomass compared to controls grown at the same temperature. Across a very large range in δ13Ca (≈ 24 ‰) and pCO2 (≈ 740 ppmv) we observed a consistent correlation between δ13Ca and δ13Cp (p<0.001). We show an average isotopic depletion of -25.4 ‰ for above-ground tissue and -23.2 ‰ for below-ground tissue of Raphanus sativus L. relative to the composition of the atmosphere under which it formed. For both above- and below-ground tissue, grown at both ~23 °C and ~29 °C, correlation was strong and significant (r2 ≥ 0.98, p<0.001); variation in pCO2 level had little or no effect on this relationship.

  1. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  2. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  3. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  4. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  5. 33 CFR 80.1440 - Port Allen, Kauai, HI.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Port Allen, Kauai, HI. 80.1440 Section 80.1440 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Islands § 80.1440 Port Allen, Kauai, HI. A line drawn...

  6. An Estimate of the Cost of Electricity from Light Water Reactors and Fossil Plants with Carbon Capture and Sequestration

    SciTech Connect

    Simon, A J

    2009-08-21

    As envisioned in this report, LIFE technology lends itself to large, centralized, baseload (or 'always on') electrical generation. Should LIFE plants be built, they will have to compete in the electricity market with other generation technologies. We consider the economics of technologies with similar operating characteristics: significant economies of scale, limited capacity for turndown, zero dependence on intermittent resources and ability to meet environmental constraints. The five generation technologies examined here are: (1) Light Water Reactors (LWR); (2) Coal; (3) Coal with Carbon Capture and Sequestration (CCS); (4) Natural Gas; and (5) Natural Gas with Carbon Capture and Sequestration. We use MIT's cost estimation methodology (Du and Parsons, 2009) to determine the cost of electricity at which each of these technologies is viable.

  7. Impact assessment of dredging to remove coal fly ash at the Tennessee Valley Authority Kingston Fossil plant using fathead minnow elutriate exposures.

    PubMed

    Stanley, Jacob K; Kennedy, Alan J; Bednar, Anthony J; Chappell, Mark A; Seiter, Jennifer M; Averett, Daniel E; Steevens, Jeffery A

    2013-04-01

    On December 22, 2008, failure of an earthen containment structure resulted in the release of approximately 4.1 million m(3) of coal fly ash into the Emory River and the surrounding area from the Tennessee Valley Authority Kingston Fossil Plant near Kingston, Tennessee, USA. The purpose of the present study was to assess the potential of dredging activities performed to remove the fly ash from the river to result in increased risk to pelagic fish, with special consideration of mobilization of metals. Elutriates were created using two sources of fly ash by bubbling with air over 10 d. This elutriate preparation method was designed to represent worst-case conditions for oxidation, metal release, and dissolution. Larval and juvenile Pimephales promelas underwent 10-d exposures to these elutriates. Larval end points included survival and biomass, and juvenile end points included survival, length, biomass, liver somatic index, and bioaccumulation. No significant toxicity was observed. Bioaccumulation of metals in juveniles was found to be primarily attributable to metals associated with particles in the gut. Results suggest little potential for toxicity to related fish species due to fly ash removal dredging activities given the extreme conditions represented by the elutriates in the present study.

  8. Evaluation of vost and semivost methods for halogenated compounds in the Clean Air Act amendments title III. Validation study at fossil fuel plant

    SciTech Connect

    Jackson, M.D.; Knoll, J.E.; Midgett, M.R.; McGaughey, J.F.; Bursey, J.T.

    1993-01-01

    The Clean Air Act Amendments of 1990 (CAAA), Title III, present a need for stationary source sampling and analytical methods for the list of 189 toxic air pollutants. The US Environmental Protection Agency (EPA) has used VOST and SemiVOST sampling and analytical methods for a wide variety of volatile and semivolatile organic compounds in the past, but these methodologies have been completely validated for only a few of the organic compounds. The applicability of VOST and SemiVOST techniques to the halogenated organic compounds listed in Title III of the Clean Air Act Amendments of 1990 has been evaluated under laboratory conditions for chromatographic separation, mass spectrometric response, sorbent recovery and analytical method detection limit. Dynamic spiking techniques for the sampling trains (both gaseous and liquid dynamic spiking) were also evaluated in the laboratory. In the study, the VOST and SemiVOST methods were evaluated in the field at a fossil fuel power plant. The source was selected to provide actual stationary source emissions with the compounds of interest present in trace amounts or not present. The paper presents the results of the field validation of the VOST and SemiVOST sampling and analytical methods.

  9. Fossil fuel furnace reactor

    DOEpatents

    Parkinson, William J.

    1987-01-01

    A fossil fuel furnace reactor is provided for simulating a continuous processing plant with a batch reactor. An internal reaction vessel contains a batch of shale oil, with the vessel having a relatively thin wall thickness for a heat transfer rate effective to simulate a process temperature history in the selected continuous processing plant. A heater jacket is disposed about the reactor vessel and defines a number of independent controllable temperature zones axially spaced along the reaction vessel. Each temperature zone can be energized to simulate a time-temperature history of process material through the continuous plant. A pressure vessel contains both the heater jacket and the reaction vessel at an operating pressure functionally selected to simulate the continuous processing plant. The process yield from the oil shale may be used as feedback information to software simulating operation of the continuous plant to provide operating parameters, i.e., temperature profiles, ambient atmosphere, operating pressure, material feed rates, etc., for simulation in the batch reactor.

  10. Allenes in Asymmetric Catalysis. Asymmetric Ring-Opening of Meso-Epoxides Catalyzed by Allene-Containing Phosphine Oxides

    PubMed Central

    Pu, Xiaotao; Qi, Xiangbing; Ready, Joseph M.

    2009-01-01

    Unsymmetrically substituted allenes (1,2 dienes) are inherently chiral and can be prepared in optically pure form. Nonetheless, to date the allene framework has not been incorporated into ligands for asymmetric catalysis. Since allenes project functionality differently than either tetrahedral carbon or chiral biaryls, they may create complementary chiral environments. This study demonstrates that optically active C2 symmetric allene-containing bisphosphine oxides can catalyze the addition of SiCl4 to meso epoxides with high enantioselectivity. The epoxide-opening likely involves generation of a Lewis acidic, cationic (bisphosphine oxide)SiCl3 complex. The fact that high asymmetric induction is observed suggests that allenes may represent a new platform for the development of ligands and catalysts for asymmetric synthesis. PMID:19722613

  11. Fossil oak galls preserve ancient multitrophic interactions.

    PubMed

    Stone, Graham N; van der Ham, Raymond W J M; Brewer, Jan G

    2008-10-07

    Trace fossils of insect feeding have contributed substantially to our understanding of the evolution of insect-plant interactions. The most complex phenotypes of herbivory are galls, whose diagnostic morphologies often allow the identification of the gall inducer. Although fossil insect-induced galls over 300Myr old are known, most are two-dimensional impressions lacking adequate morphological detail either for the precise identification of the causer or for detection of the communities of specialist parasitoids and inquilines inhabiting modern plant galls. Here, we describe the first evidence for such multitrophic associations in Pleistocene fossil galls from the Eemian interglacial (130000-115000 years ago) of The Netherlands. The exceptionally well-preserved fossils can be attributed to extant species of Andricus gallwasps (Hymenoptera: Cynipidae) galling oaks (Quercus), and provide the first fossil evidence of gall attack by herbivorous inquiline gallwasps. Furthermore, phylogenetic placement of one fossil in a lineage showing obligate host plant alternation implies the presence of a second oak species, Quercus cerris, currently unknown from Eemian fossils in northwestern Europe. This contrasts with the southern European native range of Q. cerris in the current interglacial and suggests that gallwasp invasions following human planting of Q. cerris in northern Europe may represent a return to preglacial distribution limits.

  12. Fe-Al Weld Overlay and High Velocity Oxy-Fuel Thermal Spray Coatings for Corrosion Protection of Waterwalls in Fossil Fired Plants with Low NOx Burners

    SciTech Connect

    Regina, J.R.

    2002-02-08

    Iron-aluminum-chromium coatings were investigated to determine the best candidates for coatings of boiler tubes in Low NOx fossil fueled power plants. Ten iron-aluminum-chromium weld claddings with aluminum concentrations up to 10wt% were tested in a variety of environments to evaluate their high temperature corrosion resistance. The weld overlay claddings also contained titanium additions to investigate any beneficial effects from these ternary and quaternary alloying additions. Several High-Velocity Oxy-Fuel (HVOF) thermal spray coatings with higher aluminum concentrations were investigated as well. Gaseous corrosion testing revealed that at least 10wt%Al is required for protection in the range of environments examined. Chromium additions were beneficial in all of the environments, but additions of titanium were beneficial only in sulfur rich atmospheres. Similar results were observed when weld claddings were in contact with corrosive slag while simultaneously, exposed to the corrosive environments. An aluminum concentration of 10wt% was required to prevent large amounts of corrosion to take place. Again chromium additions were beneficial with the greatest corrosion protection occurring for welds containing both 10wt%Al and 5wt%Cr. The exposed thermal spray coatings showed either significant cracking within the coating, considerable thickness loss, or corrosion products at the coating substrate interface. Therefore, the thermal spray coatings provided the substrate very little protection. Overall, it was concluded that of the coatings studied weld overlay coatings provide superior protection in these Low NOx environments; specifically, the ternary weld composition of 10wt%Al and 5wt%Cr provided the best corrosion protection in all of the environments tested.

  13. Spatial and temporal trends in contaminant concentrations in Hexagenia nymphs following a coal ash spill at the Tennessee Valley Authority's Kingston Fossil Plant

    SciTech Connect

    Baker, Tyler F; Jett, Robert Trent; Smith, John G.; Murphy, Cheryl A.

    2016-02-25

    A dike failure at the Tennessee Valley Authority Kingston Fossil Plant in East Tennessee, United States, in December 2008, released approximately 4.1 million m3 of coal ash into the Emory River. From 2009 through 2012, samples of mayfly nymphs (Hexagenia bilineata) were collected each spring from sites in the Emory, Clinch, and Tennessee Rivers upstream and downstream of the spill. Samples were analyzed for 17 metals. Concentrations of metals were generally highest the first 2 miles downstream of the spill, and then decreased with increasing distance from the spill. Arsenic, B, Ba, Be, Mo, Sb, Se, Sr, and V appeared to have strong ash signatures, whereas Co, Cr, Cu, Ni, and Pb appeared to be associated with ash and other sources. Furthermore, the concentrations for most of these contaminants were modest and are unlikely to cause widespread negative ecological effects. Trends in Hg, Cd, and Zn suggested little (Hg) or no (Cd, Zn) association with ash. Temporal trends suggested that concentrations of ash-related contaminants began to subside after 2010, but because of the limited time period of that analysis (4 yr), further monitoring is needed to verify this trend. The present study provides important information on the magnitude of contaminant exposure to aquatic receptors from a major coal ash spill, as well as spatial and temporal trends for transport of the associated contaminants in a large open watershed. Environ Toxicol Chem 2016;35:1159 1171. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

  14. Spatial and temporal trends in contaminant concentrations in Hexagenia nymphs following a coal ash spill at the Tennessee Valley Authority's Kingston Fossil Plant

    DOE PAGES

    Baker, Tyler F; Jett, Robert Trent; Smith, John G.; ...

    2016-02-25

    A dike failure at the Tennessee Valley Authority Kingston Fossil Plant in East Tennessee, United States, in December 2008, released approximately 4.1 million m3 of coal ash into the Emory River. From 2009 through 2012, samples of mayfly nymphs (Hexagenia bilineata) were collected each spring from sites in the Emory, Clinch, and Tennessee Rivers upstream and downstream of the spill. Samples were analyzed for 17 metals. Concentrations of metals were generally highest the first 2 miles downstream of the spill, and then decreased with increasing distance from the spill. Arsenic, B, Ba, Be, Mo, Sb, Se, Sr, and V appearedmore » to have strong ash signatures, whereas Co, Cr, Cu, Ni, and Pb appeared to be associated with ash and other sources. Furthermore, the concentrations for most of these contaminants were modest and are unlikely to cause widespread negative ecological effects. Trends in Hg, Cd, and Zn suggested little (Hg) or no (Cd, Zn) association with ash. Temporal trends suggested that concentrations of ash-related contaminants began to subside after 2010, but because of the limited time period of that analysis (4 yr), further monitoring is needed to verify this trend. The present study provides important information on the magnitude of contaminant exposure to aquatic receptors from a major coal ash spill, as well as spatial and temporal trends for transport of the associated contaminants in a large open watershed. Environ Toxicol Chem 2016;35:1159 1171. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.« less

  15. Historic American Buildings Survey Harold Allen, Photographer, June, 1964 VIEW: ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Historic American Buildings Survey Harold Allen, Photographer, June, 1964 VIEW: EXTERIOR: WEST (CLARK STREET) AND SOUTH (JACKSON BLVD.) SIDES - U.S. Post Office, Customs House & Sub-Treasury, 218 South Dearborn Street, Chicago, Cook County, IL

  16. 8. Historic American Buildings Survey Harold Allen, Photographer 24 June ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Historic American Buildings Survey Harold Allen, Photographer 24 June 1964 GRAND STAIRWAY, FROM SECOND FLOOR HALL, SHOWING STAINED GLASS WINDOW IN WEST WALL ABOVE LANDING - Francis J. Dewes House, 503 West Wrightwood Avenue, Chicago, Cook County, IL

  17. 6. Historic American Buildings Survey Harold Allen, Photographer June 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Historic American Buildings Survey Harold Allen, Photographer June 1964 STAINED GLASS WINDOW, WEST WINDOW IN SOUTH WALL, FROM BALCONY - Kehilath Anshe Ma'ariv Synagogue, 3301 South Indiana Avenue, Chicago, Cook County, IL

  18. 1. Historic American Buildings Survey Harold Allen, Photographer 24 May ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey Harold Allen, Photographer 24 May 1964 (R. TO L.) MANHATTAN BLDG. (WEST FRONT AND SOUTH SIDES), OLD COLONY BLDG., FISHER BLDG., MONADNOCK BLOCK - Manhattan Building, 431 South Dearborn Street, Chicago, Cook County, IL

  19. Substituent effects on dynamics at conical intersections: Allene and methyl allenes

    NASA Astrophysics Data System (ADS)

    Neville, Simon P.; Wang, Yanmei; Boguslavskiy, Andrey E.; Stolow, Albert; Schuurman, Michael S.

    2016-01-01

    We report a joint experimental and theoretical study on the ultrafast excited state dynamics of allene and a series of its methylated analogues (1,2-butadiene, 1,1-dimethylallene, and tetramethylallene) in order to elucidate the conical intersection mediated dynamics that give rise to ultrafast relaxation to the ground electronic state. We use femtosecond time-resolved photoelectron spectroscopy (TRPES) to probe the coupled electronic-vibrational dynamics following UV excitation at 200 nm (6.2 eV). Ab initio multiple spawning (AIMS) simulations are employed to determine the mechanistic details of two competing dynamical pathways to the ground electronic state. In all molecules, these pathways are found to involve as follows: (i) twisting about the central allenic C-C-C axis followed by pyramidalization at one of the terminal carbon atoms and (ii) bending of allene moiety. Importantly, the AIMS trajectory data were used for ab initio simulations of the TRPES, permitting direct comparison with experiment. For each molecule, the decay of the TRPES signal is characterized by short (30 fs, 52 fs, 23 fs) and long (1.8 ps, 3.5 ps, [306 fs, 18 ps]) time constants for 1,2-butadiene, 1,1-dimethylallene, and tetramethylallene, respectively. However, AIMS simulations show that these time constants are only loosely related to the evolution of electronic character and actually more closely correlate to large amplitude motions on the electronic excited state, modulating the instantaneous vertical ionization potentials. Furthermore, the fully substituted tetramethylallene is observed to undergo qualitatively different dynamics, as displacements involving the relatively massive methyl groups impede direct access to the conical intersections which give rise to the ultrafast relaxation dynamics observed in the other species. These results show that the branching between the "twisting" and "bending" pathways can be modified via the selective methylation of the terminal carbon atoms of

  20. Substituent effects on dynamics at conical intersections: Allene and methyl allenes.

    PubMed

    Neville, Simon P; Wang, Yanmei; Boguslavskiy, Andrey E; Stolow, Albert; Schuurman, Michael S

    2016-01-07

    We report a joint experimental and theoretical study on the ultrafast excited state dynamics of allene and a series of its methylated analogues (1,2-butadiene, 1,1-dimethylallene, and tetramethylallene) in order to elucidate the conical intersection mediated dynamics that give rise to ultrafast relaxation to the ground electronic state. We use femtosecond time-resolved photoelectron spectroscopy (TRPES) to probe the coupled electronic-vibrational dynamics following UV excitation at 200 nm (6.2 eV). Ab initio multiple spawning (AIMS) simulations are employed to determine the mechanistic details of two competing dynamical pathways to the ground electronic state. In all molecules, these pathways are found to involve as follows: (i) twisting about the central allenic C-C-C axis followed by pyramidalization at one of the terminal carbon atoms and (ii) bending of allene moiety. Importantly, the AIMS trajectory data were used for ab initio simulations of the TRPES, permitting direct comparison with experiment. For each molecule, the decay of the TRPES signal is characterized by short (30 fs, 52 fs, 23 fs) and long (1.8 ps, 3.5 ps, [306 fs, 18 ps]) time constants for 1,2-butadiene, 1,1-dimethylallene, and tetramethylallene, respectively. However, AIMS simulations show that these time constants are only loosely related to the evolution of electronic character and actually more closely correlate to large amplitude motions on the electronic excited state, modulating the instantaneous vertical ionization potentials. Furthermore, the fully substituted tetramethylallene is observed to undergo qualitatively different dynamics, as displacements involving the relatively massive methyl groups impede direct access to the conical intersections which give rise to the ultrafast relaxation dynamics observed in the other species. These results show that the branching between the "twisting" and "bending" pathways can be modified via the selective methylation of the terminal carbon atoms of

  1. Substituent effects on dynamics at conical intersections: Allene and methyl allenes

    SciTech Connect

    Neville, Simon P.; Wang, Yanmei; Boguslavskiy, Andrey E.; Stolow, Albert; Schuurman, Michael S.

    2016-01-07

    We report a joint experimental and theoretical study on the ultrafast excited state dynamics of allene and a series of its methylated analogues (1,2-butadiene, 1,1-dimethylallene, and tetramethylallene) in order to elucidate the conical intersection mediated dynamics that give rise to ultrafast relaxation to the ground electronic state. We use femtosecond time-resolved photoelectron spectroscopy (TRPES) to probe the coupled electronic-vibrational dynamics following UV excitation at 200 nm (6.2 eV). Ab initio multiple spawning (AIMS) simulations are employed to determine the mechanistic details of two competing dynamical pathways to the ground electronic state. In all molecules, these pathways are found to involve as follows: (i) twisting about the central allenic C–C–C axis followed by pyramidalization at one of the terminal carbon atoms and (ii) bending of allene moiety. Importantly, the AIMS trajectory data were used for ab initio simulations of the TRPES, permitting direct comparison with experiment. For each molecule, the decay of the TRPES signal is characterized by short (30 fs, 52 fs, 23 fs) and long (1.8 ps, 3.5 ps, [306 fs, 18 ps]) time constants for 1,2-butadiene, 1,1-dimethylallene, and tetramethylallene, respectively. However, AIMS simulations show that these time constants are only loosely related to the evolution of electronic character and actually more closely correlate to large amplitude motions on the electronic excited state, modulating the instantaneous vertical ionization potentials. Furthermore, the fully substituted tetramethylallene is observed to undergo qualitatively different dynamics, as displacements involving the relatively massive methyl groups impede direct access to the conical intersections which give rise to the ultrafast relaxation dynamics observed in the other species. These results show that the branching between the “twisting” and “bending” pathways can be modified via the selective methylation of the terminal

  2. Regiodivergent and Stereoselective Hydrosilylation of 1,3-Disubstituted Allenes.

    PubMed

    Miller, Zachary D; Dorel, Ruth; Montgomery, John

    2015-07-27

    Methods for the highly stereoselective and regiodivergent hydrosilylation of 1,3-disubstituted allenes have been developed. The synthesis of E allylsilanes is accomplished with palladium NHC catalysts, and trisubstituted Z alkenylsilanes are accessed with nickel NHC catalysts. Unsymmetrically substituted allenes are well tolerated with nickel catalysis and afford Z alkenylsilanes. Evidence for a plausible mechanism was obtained through an isotopic double-labeling crossover study.

  3. Reactivity and Chemoselectivity of Allenes in Rh(I)-Catalyzed Intermolecular (5 + 2) Cycloadditions with Vinylcyclopropanes: Allene-Mediated Rhodacycle Formation Can Poison Rh(I)-Catalyzed Cycloadditions

    PubMed Central

    2015-01-01

    Allenes are important 2π building blocks in organic synthesis and engage as 2-carbon components in many metal-catalyzed reactions. Wender and co-workers discovered that methyl substituents on the terminal allene double bond counterintuitively change the reactivities of allenes in [Rh(CO)2Cl]2-catalyzed intermolecular (5 + 2) cycloadditions with vinylcyclopropanes (VCPs). More sterically encumbered allenes afford higher cycloadduct yields, and such effects are also observed in other Rh(I)-catalyzed intermolecular cycloadditions. Through density functional theory calculations (B3LYP and M06) and experiment, we explored this enigmatic reactivity and selectivity of allenes in [Rh(CO)2Cl]2-catalyzed intermolecular (5 + 2) cycloadditions with VCPs. The apparent low reactivity of terminally unsubstituted allenes is associated with a competing allene dimerization that irreversibly sequesters rhodium. With terminally substituted allenes, steric repulsion between the terminal substituents significantly increases the barrier of allene dimerization while the barrier of the (5 + 2) cycloaddition is not affected, and thus the cycloaddition prevails. Computation has also revealed the origin of chemoselectivity in (5 + 2) cycloadditions with allene-ynes. Although simple allene and acetylene have similar reaction barriers, intermolecular (5 + 2) cycloadditions of allene-ynes occur exclusively at the terminal allene double bond. The terminal double bond is more reactive due to the enhanced d−π* backdonation. At the same time, insertion of the internal double bond of an allene-yne has a higher barrier as it would break π conjugation. Substituted alkynes are more difficult to insert compared with acetylene, because of the steric repulsion from the additional substituents. This leads to the greater reactivity of the allene double bond relative to the alkynyl group in allene-ynes. PMID:25379606

  4. Fossilized bioelectric wire - the trace fossil Trichichnus.

    PubMed

    Kędzierski, M; Uchman, A; Sawlowicz, Z; Briguglio, A

    2015-04-16

    The trace fossil Trichichnus is proposed as an indicator of fossil bioelectric bacterial activity at the oxic-anoxic interface zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past. Trichichnus is an exceptional trace fossil due to its very thin diameter (mostly less than 1 mm) and common pyritic filling. It is ubiquitous in some fine-grained sediments, where it has been interpreted as a burrow formed deeper than any other trace fossils, below the redox boundary. Trichichnus, formerly referred to as deeply burrowed invertebrates, has been found as remnant of a fossilized intrasediment bacterial mat that is pyritized. As visualized in 3-D by means of X-ray computed microtomography scanner, Trichichnus forms dense filamentous fabric, which reflects that it is produced by modern large, mat-forming, sulfide-oxidizing bacteria, belonging mostly to Thioploca-related taxa, which are able to house a complex bacterial consortium. Several stages of Trichichnus formation, including filamentous, bacterial mat and its pyritization, are proposed to explain an electron exchange between oxic and suboxic/anoxic layers in the sediment. Therefore, Trichichnus can be considered a fossilized "electric wire".

  5. Fossilized bioelectric wire - the trace fossil Trichichnus

    NASA Astrophysics Data System (ADS)

    Kędzierski, M.; Uchman, A.; Sawlowicz, Z.; Briguglio, A.

    2014-12-01

    The trace fossil Trichichnus is proposed as an indicator of fossil bioelectric bacterial activity at the interface oxic - anoxic zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past. Trichichnus is an exceptional trace fossil due to its very thin diameter (mostly less than 1 mm) and common pyritic filling. It is ubiquitous in some fine-grained sediments, where it has been interpreted as a burrow formed deeper than any other trace fossils, below the redox boundary. Trichichnus formerly referred to as deeply burrowed invertebrates, has been found as remnant of a fossilized intrasediment bacterial mat that is pyritized. As visualized in 3-D by means of X-ray computed microtomography scanner, Trichichnus forms dense filamentous fabric, which reflects that produced by modern large, mat-forming, sulphide-oxidizing bacteria, belonging mostly to Trichichnus-related taxa, which are able to house a complex bacterial consortium. Several stages of Trichichnus formation, including filamentous, bacterial mat and its pyritization, are proposed to explain an electron exchange between oxic and suboxic/anoxic layers in the sediment. Therefore, Trichichnus can be considered a fossilized "electric wire".

  6. Fossilized bioelectric wire - the trace fossil Trichichnus

    NASA Astrophysics Data System (ADS)

    Kędzierski, M.; Uchman, A.; Sawlowicz, Z.; Briguglio, A.

    2015-04-01

    The trace fossil Trichichnus is proposed as an indicator of fossil bioelectric bacterial activity at the oxic-anoxic interface zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past. Trichichnus is an exceptional trace fossil due to its very thin diameter (mostly less than 1 mm) and common pyritic filling. It is ubiquitous in some fine-grained sediments, where it has been interpreted as a burrow formed deeper than any other trace fossils, below the redox boundary. Trichichnus, formerly referred to as deeply burrowed invertebrates, has been found as remnant of a fossilized intrasediment bacterial mat that is pyritized. As visualized in 3-D by means of X-ray computed microtomography scanner, Trichichnus forms dense filamentous fabric, which reflects that it is produced by modern large, mat-forming, sulfide-oxidizing bacteria, belonging mostly to Thioploca-related taxa, which are able to house a complex bacterial consortium. Several stages of Trichichnus formation, including filamentous, bacterial mat and its pyritization, are proposed to explain an electron exchange between oxic and suboxic/anoxic layers in the sediment. Therefore, Trichichnus can be considered a fossilized "electric wire".

  7. Obituary: James Alfred Van Allen, 1914-2006

    NASA Astrophysics Data System (ADS)

    Ludwig, George H.; McIlwain, Carl Edwin

    2006-12-01

    James Alfred Van Allen, world-renowned space scientist, died 9 August 2006 at the age of ninety-one. He succumbed to heart failure after a ten-week period of declining health. Van Allen served for his entire sixty-seven-year professional career as an amazingly productive researcher, space science spokesman, inspired teacher, and valued colleague. The realization by him and his associates that charged particles are trapped by the Earth's magnetic field began a whole new field of research, magnetospheric physics. Following that initial discovery, he and his associates quickly extended their observations, first to the inner planets, and then to the rest of the planets and beyond. During his tenure at Iowa, he and his group flew instruments on more than sixty successful Earth satellites and planetary spacecraft, including the first missions to the planets Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. Van Allen's lifetime publication list numbers more than 275, of which many are widely-cited, seminal papers. He was the sole author of more than 125 of those papers. Beyond the research laboratory, Van Allen worked energetically throughout his career in establishing space research as a new branch of human inquiry. He was among the most sought-after as a committee member and adviser, working at the highest levels of government, including the White House and Congress, and at all levels of the national and international research establishments. Many presentations in the non-scientific arena helped to bring the exciting discoveries and challenges of space research to the attention of the general public. James Van Allen (Van to his many friends and colleagues) was born on 7 September 1914 on a small farm near Mount Pleasant, Iowa, the second of four sons of Alfred Morris Van Allen and Alma Olney Van Allen. After high school in Mount Pleasant, he entered Iowa Wesleyan College, majoring in physics and graduating summa cum laude. While there, he was introduced to geophysics

  8. Fossil energy program. Progress report, July 1980

    SciTech Connect

    McNeese, L. E.

    1980-10-01

    This report - the seventy-second of a series - is a compendium of monthly progress reports for the ORNL research and development programs that are in support of the increased utilization of coal and other fossil fuel alternatives to oil and gas as sources of clean energy. The projects reported this month include those for coal conversion development, chemical research and development, materials technology, component development and process evaluation, technical support to major liquefaction projects, process and program analysis, fossil energy environmental analysis, coal preparation and waste utilization, coal preparation plant automation, atmospheric fluidized bed coal combustor for cogeneration, technical support to the TVA fluidized bed combustion demonstration plant program, fossil energy applications assessments, performance assurance system support for fossil energy projects, international assessment of atmospheric fluidized bed combustion technology, and PFBC systems analysis.

  9. On the metallic nature of carbon in allenes and heterocumulenes.

    PubMed

    Alcarazo, Manuel

    2011-03-07

    The IUPAC defines allenes as organic compounds having at least two double bonds from one carbon to two others. Thus the central carbon atom is in accord with the octet rule through the formation of two σ and two π bonds. However, this perspective highlights a series of recent experimental, as well as theoretical results, suggesting that depending on the substituents, this canonical description might not be the most adequate. In fact, in a growing number of examples the bond in allenes and related heterocumulenes is better described as an inner carbon that plays the role of the central atom of a "coordination complex" and interacts with its substituents as if they were ligands of this organic complex. This interpretation of the bond in allenes is especially useful in predicting the C(0), carbene or partial carbocationic character of the central carbon atom.

  10. Clarence Allen talks about the responsibilities in earthquake prediction

    USGS Publications Warehouse

    Spall, H.

    1978-01-01

    Dr. Clarence R. Allen is professor of geology and geophysics at the California Institute of Technology. He has been a member of advisory panels to the Executive Office of the President, National Academy of Sciences, National Science Foundation, U.S Geological Survey, UNESCO, California State Mining and Geology Board, and the California Department of Water Resources. Dr. Allen has been President of both the Geological Society of America and the Seismological Society of America (SSA). The title of this interview is based on his presidential address to the SSA in 1976. 

  11. Restoring Fossil Creek

    ERIC Educational Resources Information Center

    Flaccus, Kathleen; Vlieg, Julie; Marks, Jane C.; LeRoy, Carri J.

    2004-01-01

    Fossil Creek had been dammed for the past 90 years, and plans were underway to restore the stream. The creek runs through Central Arizona and flows from the high plateaus to the desert, cutting through the same formations that form the Grand Canyon. This article discusses the Fossil Creek monitoring project. In this project, students and teachers…

  12. Modes of Heme-Binding and Substrate Access for Cytochrome P450 CYP74A Revealed by Crystal Structures of Allene Oxide Synthase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cytochrome P450s exist ubiquitously in all organisms and are involved in many biological processes. Allene oxide synthase (AOS) is a P450 enzyme that plays a key role in the biosynthesis of oxylipin jasmonates which are involved in signal and defense reactions in higher plants. The crystal structure...

  13. 5. Historic American Buildings Survey Harold Allen, Photographer June 1964 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Historic American Buildings Survey Harold Allen, Photographer June 1964 TRIPLE STAINED GLASS WINDOWS AND COLUMN SUPPORTING BALCONY (EAST WINDOWS IN SOUTH WALL OF MAIN FLOOR OF AUDITORIUM) - Kehilath Anshe Ma'ariv Synagogue, 3301 South Indiana Avenue, Chicago, Cook County, IL

  14. Van Allen Probes Science Gateway: A Centralized Data Access Point

    NASA Astrophysics Data System (ADS)

    Romeo, G.; Barnes, R. J.; Ukhorskiy, A. Y.; Sotirelis, T.; Stephens, G. K.; Kessel, R.; Potter, M.

    2015-12-01

    The Van Allen Probes Science Gateway acts a centralized interface to the instrument Science Operation Centers (SOCs), provides mission planning tools, and hosts a number of science related activities such as the mission bibliography. Most importantly, the Gateway acts as the primary site for processing and delivering the Van Allen Probes Space Weather data to users. Over the past years, the web-site has been completely redesigned with the focus on easier navigation and improvements of the existing tools such as the orbit plotter, position calculator and magnetic footprint tool. In addition, a new data plotting facility has been added. Based on HTML5, which allows users to interactively plot Van Allen Probes science and space weather data. The user can tailor the tool to display exactly the plot they wish to see and then share this with other users via either a URL or by QR code. Various types of plots can be created, including, simple time series, data plotted as a function of orbital location, and time versus L-Shell, capability of visualizing data from both probes (A & B) on the same plot. In cooperation with all Van Allen Probes Instrument SOCs, the Science Gateway will soon be able to serve higher level data products (Level 3), and to visualize them via the above mentioned HTML5 interface. Users will also be able to create customized CDF files on the fly.

  15. The Evolving Space Weather System—Van Allen Probes Contribution

    NASA Astrophysics Data System (ADS)

    Zanetti, L. J.; Mauk, B. H.; Fox, N. J.; Barnes, R. J.; Weiss, M.; Sotirelis, T. S.; Raouafi, N.-E.; Kessel, R. L.; Becker, H. N.

    2014-10-01

    The overarching goal and purpose of the study of space weather is clear—to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800s to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA's Van Allen Probes' twin pair of satellites, launched in August of 2012 and orbiting directly through Earth's severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP), was renamed soon after launch to honor the discoverer of Earth's radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes are one part of NASA's Living With a Star program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions, and their effects on the geospace and Earth environment.

  16. Magnetic resonance spectroscopy and imaging for the study of fossils.

    PubMed

    Giovannetti, Giulio; Guerrini, Andrea; Salvadori, Piero A

    2016-07-01

    Computed tomography (CT) has long been used for investigating palaeontological specimens, as it is a nondestructive technique which avoids the need to dissolve or ionize the fossil sample. However, magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) have recently gained ground as analytical tools for examination of palaeontological samples, by nondestructively providing information about the structure and composition of fossils. While MRI techniques are able to reveal the three-dimensional geometry of the trace fossil, MRS can provide information on the chemical composition of the samples. The multidimensional nature of MR (magnetic resonance) signals has potential to provide rich three-dimensional data on the palaeontological specimens and also to help in elucidating paleopathological and paleoecological questions. In this work the verified applications and the emerging uses of MRI and MRS in paleontology are reviewed, with particular attention to fossil spores, fossil plants, ambers, fossil invertebrates, and fossil vertebrate studies.

  17. A study on the impact of nuclear power plant construction relative to decommissioning Fossil Fuel Power Plant in order to reduce carbon dioxide emissions using a modified Nordhaus Vensim DICE model

    NASA Astrophysics Data System (ADS)

    Colpetzer, Jason Lee

    The current levels of CO2 emissions and high levels accumulating in the atmosphere have climate scientists concerned. The Dynamic Integrated Climate Economy Model or "DICE" for short is a highly developed model that has been used to simulate climate change and evaluate factors addressing global warming. The model was developed by Yale's Nordhaus along with collaborators and the compilation of numerous scientific publications. The purpose of this study is to recreate DICE using Vensim and modify it to evaluate the use of nuclear power plants (NPPs) as a means to counter global temperature increases in the atmosphere and oceans and the associated cost of damages. The amount of greenhouse gas emissions from a NPP are about 6% per Megawatt as that from a Fossil Fuel Power Plant (FFPP). Based on this, a model was developed to simulate construction of NPPs with subsequent decommissioning of FFPPs with an equivalent power output. The results produced through multiple simulation runs utilizing variable NPP construction rates show that some minor benefit is achievable if all of the more than 10,000 FFPPs currently in operation in the U.S. are replaced with NPPs. The results show that a reduction in CO 2 emissions of 2.48% will occur if all of the FFPPs are decommissioned. At a minimum rate of 50 NPPs constructed per year, the largest reduction in CO2 in the atmosphere, 1.94% or 44.5 billion tons of carbon, is possible. This results in a reduction in global warming of 0.068°C or 1.31%. The results also show that this reduction in global warming will be equivalent to a reduction of 8.2% or $148 B in anticipated annual spending as a result of climate change damages. Further results indicate that using NPPs to address climate change will provide a small benefit; ultimately, it will not be enough to reduce CO2 emissions or atmospheric CO 2 to control global warming. The amount of CO2 in the atmosphere is predicted to be 1055 parts per million (ppm) even in the best case

  18. Fossil fuels -- future fuels

    SciTech Connect

    1998-03-01

    Fossil fuels -- coal, oil, and natural gas -- built America`s historic economic strength. Today, coal supplies more than 55% of the electricity, oil more than 97% of the transportation needs, and natural gas 24% of the primary energy used in the US. Even taking into account increased use of renewable fuels and vastly improved powerplant efficiencies, 90% of national energy needs will still be met by fossil fuels in 2020. If advanced technologies that boost efficiency and environmental performance can be successfully developed and deployed, the US can continue to depend upon its rich resources of fossil fuels.

  19. Infrared Spectra of Fossils,

    DTIC Science & Technology

    fossil’s surface is accessible to the analyzing beams. The technique is potentially valuable for the examination of special samples of palaeontological and archaeological interest. Keywords include: Photothermal effect.

  20. Natural Product Molecular Fossils.

    PubMed

    Falk, Heinz; Wolkenstein, Klaus

    2017-01-01

    The natural products synthesized by organisms that were living a long time ago gave rise to their molecular fossils. These can consist of either the original unchanged compounds or they may undergo peripheral transformations in which their skeletons remain intact. In cases when molecular fossils can be traced to their organismic source, they are termed "geological biomarkers".This contribution describes apolar and polar molecular fossils and, in particular biomarkers, along the lines usually followed in organic chemistry textbooks, and points to their bioprecursors when available. Thus, the apolar compounds are divided in linear and branched alkanes followed by alicyclic compounds and aromatic and heterocyclic molecules, and, in particular, the geoporphyrins. The polar molecular fossils contain as functional groups or constituent units ethers, alcohols, phenols, carbonyl groups, flavonoids, quinones, and acids, or are polymers like kerogen, amber, melanin, proteins, or nucleic acids. The final sections discuss the methodology used and the fundamental processes encountered by the biomolecules described, including diagenesis, catagenesis, and metagenesis.

  1. Fossil Simulation in the Classroom

    ERIC Educational Resources Information Center

    Hoehn, Robert G.

    1977-01-01

    Describes classroom science demonstrations and experiments that simulate the process of fossil formation. Lists materials, procedures and suggestions for successful activities. Includes ten student activities (coral fossils, leaf fossils, leaf scars, carbonization, etc.). Describes a fossil game in which students work in pairs. (CS)

  2. Isomer-specific combustion chemistry in allene and propyne flames

    SciTech Connect

    Hansen, Nils; Miller, James A.; Westmoreland, Phillip R.; Kasper, Tina; Kohse-Hoeinghaus, Katharina; Wang, Juan; Cool, Terrill A.

    2009-11-15

    A combined experimental and modeling study is performed to clarify the isomer-specific combustion chemistry in flames fueled by the C{sub 3}H{sub 4} isomers allene and propyne. To this end, mole fraction profiles of several flame species in stoichiometric allene (propyne)/O{sub 2}/Ar flames are analyzed by means of a chemical kinetic model. The premixed flames are stabilized on a flat-flame burner under a reduced pressure of 25 Torr (=33.3 mbar). Quantitative species profiles are determined by flame-sampling molecular-beam mass spectrometry, and the isomer-specific flame compositions are unraveled by employing photoionization with tunable vacuum-ultraviolet synchrotron radiation. The temperature profiles are measured by OH laser-induced fluorescence. Experimental and modeled mole fraction profiles of selected flame species are discussed with respect to the isomer-specific combustion chemistry in both flames. The emphasis is put on main reaction pathways of fuel consumption, of allene and propyne isomerization, and of isomer-specific formation of C{sub 6} aromatic species. The present model includes the latest theoretical rate coefficients for reactions on a C{sub 3}H{sub 5} potential [J.A. Miller, J.P. Senosiain, S.J. Klippenstein, Y. Georgievskii, J. Phys. Chem. A 112 (2008) 9429-9438] and for the propargyl recombination reactions [Y. Georgievskii, S.J. Klippenstein, J.A. Miller, Phys. Chem. Chem. Phys. 9 (2007) 4259-4268]. Larger peak mole fractions of propargyl, allyl, and benzene are observed in the allene flame than in the propyne flame. In these flames virtually all of the benzene is formed by the propargyl recombination reaction. (author)

  3. Van Allen Probes Science Gateway and Space Weather Data Processing

    NASA Astrophysics Data System (ADS)

    Romeo, G.; Barnes, R. J.; Weiss, M.; Fox, N. J.; Mauk, B.; Potter, M.; Kessel, R.

    2014-12-01

    The Van Allen Probes Science Gateway acts as a centralized interface to the instrument Science Operation Centers (SOCs), provides mission planning tools, and hosts a number of science related activities such as the mission bibliography. Most importantly, the Gateway acts as the primary site for processing and delivering the VAP Space Weather data to users. Over the past year, the web-site has been completely redesigned with the focus on easier navigation and improvements of the existing tools such as the orbit plotter, position calculator and magnetic footprint tool. In addition, a new data plotting facility has been added. Based on HTML5, which allows users to interactively plot Van Allen Probes summary and space weather data. The user can tailor the tool to display exactly the plot they wish to see and then share this with other users via either a URL or by QR code. Various types of plots can be created, including simple time series, data plotted as a function of orbital location, and time versus L-Shell. We discuss the new Van Allen Probes Science Gateway and the Space Weather Data Pipeline.

  4. Recent Science Highlights of the Van Allen Probes Mission

    NASA Astrophysics Data System (ADS)

    Ukhorskiy, Aleksandr

    2016-10-01

    The morning of 30 August 2012 saw an Atlas 5 rocket launch NASA's second Living With a Star spacecraft mission, the twin Radiation Belt Storm Probes, into an elliptic orbit cutting through Earth's radiation belts. Renamed the Van Allen Probes soon after launch, the Probes are designed to determine how the highly variable populations of high-energy charged particles within the radiation belts, dangerous to astronauts and satellites, are created, respond to solar variations, and evolve in space environments. The Van Allen Probes mission extends beyond the practical considerations of the hazard's of Earth's space environment. Twentieth century observations of space and astrophysical systems throughout the solar system and out into the observable universe have shown that the processes that generate intense particle radiation within magnetized environments such as Earth's are universal. During its mission the Van Allen Probes verified and quantified previously suggested energization processes, discovered new energization mechanisms, revealed the critical importance of dynamic plasma injections into the innermost magnetosphere, and used uniquely capable instruments to reveal inner radiation belt features that were all but invisible to previous sensors. This paper gives a brief overview of the mission, presents some recent science highlights, and discusses plans for the extended mission.

  5. Fossil Fuel Biomarkers in Sewage Sludges: Environmental Significance

    NASA Astrophysics Data System (ADS)

    Payet, C.; Bryselbout, C.; Morel, J.-L.; Lichtfouse, E.

    Fossil fuel biomarkers, or "molecular fossils," are specific organic substances found in coals, petroleums, and sedimentary rocks. They are formed during millions of years of sedimentary burial by geochemical alteration of biological molecules, such as cholesterol, under the effect of biodegradation, temperature, pressure, and mineral catalysis, to produce geochemically mature molecules, for example, aromatic steroids (Fig. 1). Since fossil fuel biomarkers have a very specific molecular structure betraying fossil fuel sources, such markers should be useful in assessing the fossil fuel contamination of various modern media such as soils, plants, waters, and modern sediments. Here the identification of fossil fuel biomarkers of high geothermal maturity in sewage sludges provides evidence of the contamination of sludges by petroleum products. The most likely sources of contamination are contaminated vegetal food, road dust, and soil particles carried by rain water.

  6. Fossil-bearing deposits from the Bukpyeong Formation (Miocene) in the Bukpyeong Basin at Donghae city, Gangwon-do, South Korea: occurrences, taphonomy and paleoenvironmental implications

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Joo; Jeong, Eun Kyoung; Uemura, Kazuhiko; Kim, Kyungsik; Paik, In Sung

    2016-04-01

    Abundant and diverse plant fossils such as land plants and subaqueous plants, freshwater mollusc fossils and invertebrate trace fossils are found in the Miocene Bukpyeong Formation at Donghae city, Gangwon-do, South Korea. Occurrences and taphofacies of the fossil-bearing deposits from the Bukpyeong Formation are described and their taphonomy and paleoenvironmental implications are interpreted. Based on fossil occurrences, lithofacies and sedimentary features of the fossil-bearing deposits, eight taphofacies are classified as the following: (1) Taphofacies 1: Gastropod fossils in massive silty mudstone; (2) Taphofacies 2: Bivalve fossils in massive silty mudstone; (3) Taphofacies 3: Plant fossils (leaf fossils) in massive silty mudstone; (4) Taphofacies 4: Gastropod and plant fossils in massive silty mudstone; (5) Taphofacies 5: Plant fossils in weakly fissile silty mudstone; (6) Taphofacies 6: Plant fossils (leaf fossils) in thin-bedded and graded silty mudstone to mudstone (claystone); (7) Taphofacies 7: Plant fragment fossils in thin-bedded and graded silty mudstone to mudstone (claystone); (8) Taphofacies 8: Plant debris in planar- to cross-laminated fine-grained sandstone. Taphonomy of taphofacies 1, 2, and 4 including freshwater mollusc fossils is interpreted to have been reworked or transported by turbidity currents after death and deposited in shallow lake to open lake. Taphonomy of taphofacies 3, 5, 6, and 7 including plant fossils is interpreted to have been transported by input of episodic flooding in the land and deposited by settling down in open lake. Taphofacies 8 including plant debris has been deposited in shallow lake by input of intensive episodic flooding from the land. The occurrences and taphofacies of the fossil-bearing deposits indicate that most of the fossils were transported by turbidity current induced by input of episodic flooding in the land and deposited in shallow lake to open lake. Moreover, plant fossils from the Bukpyeong

  7. Recent synchronous radiation of a living fossil.

    PubMed

    Nagalingum, N S; Marshall, C R; Quental, T B; Rai, H S; Little, D P; Mathews, S

    2011-11-11

    Modern survivors of previously more diverse lineages are regarded as living fossils, particularly when characterized by morphological stasis. Cycads are often cited as a classic example, reaching their greatest diversity during the Jurassic-Cretaceous (199.6 to 65.5 million years ago) then dwindling to their present diversity of ~300 species as flowering plants rose to dominance. Using fossil-calibrated molecular phylogenies, we show that cycads underwent a near synchronous global rediversification beginning in the late Miocene, followed by a slowdown toward the Recent. Although the cycad lineage is ancient, our timetrees indicate that living cycad species are not much older than ~12 million years. These data reject the hypothesized role of dinosaurs in generating extant diversity and the designation of today's cycad species as living fossils.

  8. Advanced fossil energy utilization

    SciTech Connect

    Shekhawat, D.; Berry, D.; Spivey, J.; Pennline, H.; Granite, E.

    2010-01-01

    This special issue of Fuel is a selection of papers presented at the symposium ‘Advanced Fossil Energy Utilization’ co-sponsored by the Fuels and Petrochemicals Division and Research and New Technology Committee in the 2009 American Institute of Chemical Engineers (AIChE) Spring National Meeting Tampa, FL, on April 26–30, 2009.

  9. Trace Fossil Analysis

    NASA Astrophysics Data System (ADS)

    Hasiotis, Stephen T.

    2009-05-01

    Today, the study of trace fossils—ichnology—is an important subdiscipline of geology at the interface of paleontology and sedimentology, mostly because of the efforts of Adolf Seilacher. His ability to synthesize various aspects of ichnology and produce a hierarchy of marine ichna and sedimentary facies has made ichnology useful worldwide in interpreting paleodiversity, rates of sedimentation, oxygenation of bottom water and sediment pore water, and depositional energy. Seilacher's book Trace Fossil Analysis provides a glimpse into the mind, methodology, and insights of the father of modern ichnology, generated from his course notes as a professor and a guest lecturer. The title sounds misleading—readers looking for up-to-date principles and approaches to trace fossil analysis in marine and continental strata will be disappointed. In his preface, however, Seilacher clearly gives direction for the use of his text: “This is a course book—meaning that it is intended to confer not knowledge, but skill.” Thus, it is not meant as a total compilation of all trace fossils, ichnotaxonomy, ichnological interpretations, applications, or the most relevant and up-to-date references. Rather, it takes the reader on a personal journey, explaining how trace fossils are understood in the context of their three-dimensional (3-D) morphology and sedimentary facies.

  10. Assessment of the US EPA's determination of the role for CO2 capture and storage in new fossil fuel-fired power plants.

    PubMed

    Clark, Victoria R; Herzog, Howard J

    2014-07-15

    On September 20, 2013, the US Environmental and Protection Agency (EPA) proposed a revised rule for "Standards of Performance for Greenhouse Gas Emissions from New Stationary Sources: Electric Utility Generating Units". These performance standards set limits on the amount of carbon dioxide (CO2) that can be emitted per megawatt-hour (MWh) of electricity generation from new coal-fired and natural gas-fired power plants built in the US. These limits were based on determinations of "best system of emission reduction (BSER) adequately demonstrated". Central in this determination was evaluating whether Carbon Dioxide Capture and Storage (CCS) qualified as BSER. The proposed rule states that CCS qualifies as BSER for coal-fired generation but not for natural gas-fired generation. In this paper, we assess the EPA's analysis that resulted in this determination. We are not trying to judge what the absolute criteria are for CCS as the BSER but only the relative differences as related to coal- vs natural gas-fired technologies. We conclude that there are not enough differences between "base load" coal-fired and natural gas-fired power plants to justify the EPA's determination that CCS is the BSER for coal-fired power plants but not for natural gas-fired power plants.

  11. Sustainability of Fossil Fuels

    NASA Astrophysics Data System (ADS)

    Lackner, K. S.

    2002-05-01

    For a sustainable world economy, energy is a bottleneck. Energy is at the basis of a modern, technological society, but unlike materials it cannot be recycled. Energy or more precisely "negentropy" (the opposite of entropy) is always consumed. Thus, one either accepts the use of large but finite resources or must stay within the limits imposed by dilute but self-renewing resources like sunlight. The challenge of sustainable energy is exacerbated by likely growth in world energy demand due to increased population and increased wealth. Most of the world still has to undergo the transition to a wealthy, stable society with the near zero population growth that characterizes a modern industrial society. This represents a huge unmet demand. If ten billion people were to consume energy like North Americans do today, world energy demand would be ten times higher. In addition, technological advances while often improving energy efficiency tend to raise energy demand by offering more opportunity for consumption. Energy consumption still increases at close to the 2.3% per year that would lead to a tenfold increase over the course of the next century. Meeting future energy demands while phasing out fossil fuels appears extremely difficult. Instead, the world needs sustainable or nearly sustainable fossil fuels. I propose the following definition of sustainable under which fossil fuels would well qualify: The use of a technology or resource is sustainable if the intended and unintended consequences will not force its abandonment within a reasonable planning horizon. Of course sustainable technologies must not be limited by resource depletion but this is only one of many concerns. Environmental impacts, excessive land use, and other constraints can equally limit the use of a technology and thus render it unsustainable. In the foreseeable future, fossil fuels are not limited by resource depletion. However, environmental concerns based on climate change and other environmental

  12. Ants and the fossil record.

    PubMed

    LaPolla, John S; Dlussky, Gennady M; Perrichot, Vincent

    2013-01-01

    The dominance of ants in the terrestrial biosphere has few equals among animals today, but this was not always the case. The oldest ants appear in the fossil record 100 million years ago, but given the scarcity of their fossils, it is presumed they were relatively minor components of Mesozoic insect life. The ant fossil record consists of two primary types of fossils, each with inherent biases: as imprints in rock and as inclusions in fossilized resins (amber). New imaging technology allows ancient ant fossils to be examined in ways never before possible. This is particularly helpful because it can be difficult to distinguish true ants from non-ants in Mesozoic fossils. Fossil discoveries continue to inform our understanding of ancient ant morphological diversity, as well as provide insights into their paleobiology.

  13. Early evolutionary colocalization of the nuclear ribosomal 5S and 45S gene families in seed plants: evidence from the living fossil gymnosperm Ginkgo biloba

    PubMed Central

    Galián, J A; Rosato, M; Rosselló, J A

    2012-01-01

    In seed plants, the colocalization of the 5S loci within the intergenic spacer (IGS) of the nuclear 45S tandem units is restricted to the phylogenetically derived Asteraceae family. However, fluorescent in situ hybridization (FISH) colocalization of both multigene families has also been observed in other unrelated seed plant lineages. Previous work has identified colocalization of 45S and 5S loci in Ginkgo biloba using FISH, but these observations have not been confirmed recently by sequencing a 1.8 kb IGS. In this work, we report the presence of the 45S–5S linkage in G. biloba, suggesting that in seed plants the molecular events leading to the restructuring of the ribosomal loci are much older than estimated previously. We obtained a 6.0 kb IGS fragment showing structural features of functional sequences, and a single copy of the 5S gene was inserted in the same direction of transcription as the ribosomal RNA genes. We also obtained a 1.8 kb IGS that was a truncate variant of the 6.0 kb IGS lacking the 5S gene. Several lines of evidence strongly suggest that the 1.8 kb variants are pseudogenes that are present exclusively on the satellite chromosomes bearing the 45S–5S genes. The presence of ribosomal IGS pseudogenes best reconciles contradictory results concerning the presence or absence of the 45S–5S linkage in Ginkgo. Our finding that both ribosomal gene families have been unified to a single 45S–5S unit in Ginkgo indicates that an accurate reassessment of the organization of rDNA genes in basal seed plants is necessary. PMID:22354111

  14. The largest fossil rodent

    PubMed Central

    Rinderknecht, Andrés; Blanco, R. Ernesto

    2008-01-01

    The discovery of an exceptionally well-preserved skull permits the description of the new South American fossil species of the rodent, Josephoartigasia monesi sp. nov. (family: Dinomyidae; Rodentia: Hystricognathi: Caviomorpha). This species with estimated body mass of nearly 1000 kg is the largest yet recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains. The fossil derives from San José Formation, Uruguay, usually assigned to the Pliocene–Pleistocene (4–2 Myr ago), and the proposed palaeoenvironment where this rodent lived was characterized as an estuarine or deltaic system with forest communities. PMID:18198140

  15. The largest fossil rodent.

    PubMed

    Rinderknecht, Andrés; Blanco, R Ernesto

    2008-04-22

    The discovery of an exceptionally well-preserved skull permits the description of the new South American fossil species of the rodent, Josephoartigasia monesi sp. nov. (family: Dinomyidae; Rodentia: Hystricognathi: Caviomorpha). This species with estimated body mass of nearly 1000kg is the largest yet recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains. The fossil derives from San José Formation, Uruguay, usually assigned to the Pliocene-Pleistocene (4-2Myr ago), and the proposed palaeoenvironment where this rodent lived was characterized as an estuarine or deltaic system with forest communities.

  16. Petrography and microanalysis of Pennsylvanian coal-ball concretions (Herrin Coal, Illinois Basin, USA): Bearing on fossil plant preservation and coal-ball origins

    NASA Astrophysics Data System (ADS)

    Siewers, Fredrick D.; Phillips, Tom L.

    2015-11-01

    Petrographic analyses of 25 coal balls from well-studied paleobotanical profiles in the Middle Pennsylvanian Herrin Coal (Westphalian D, Illinois Basin) and five select coal balls from university collections, indicate that Herrin Coal-ball peats were permineralized by fibrous and non-fibrous carbonates. Fibrous carbonates occur in fan-like to spherulitic arrays in many intracellular (within tissue) pores, and are best developed in relatively open extracellular (between plant) pore spaces. Acid etched fibrous carbonates appear white under reflected light and possess a microcrystalline texture attributable to abundant microdolomite. Scanning electron microscopy, X-ray diffraction, and electron microprobe analysis demonstrate that individual fibers have a distinct trigonal prism morphology and are notable for their magnesium content (≈ 9-15 mol% MgCO3). Non-fibrous carbonates fill intercrystalline spaces among fibers and pores within the peat as primary precipitates and neomorphic replacements. In the immediate vicinity of plant cell walls, non-fibrous carbonates cut across fibrous carbonates as a secondary, neomorphic phase attributed to coalification of plant cell walls. Dolomite occurs as diagenetic microdolomite associated with the fibrous carbonate phase, as sparite replacements, and as void-filling cement. Maximum dolomite (50-59 wt.%) is in the top-of-seam coal-ball zone at the Sahara Mine, which is overlain by the marine Anna Shale. Coal-ball formation in the Herrin Coal began with the precipitation of fibrous high magnesium calcite. The trigonal prism morphology of the carbonate fibers suggests rapid precipitation from super-saturated, meteoric pore waters. Carbonate precipitation from marine waters is discounted on the basis of stratigraphic, paleobotanical, and stable isotopic evidence. Most non-fibrous carbonate is attributable to later diagenetic events, including void-fill replacements, recrystallization, and post-depositional fracture fills. Evidence

  17. Landscape planning for the future: using fossil records to independently validate potential threats, opportunities and likely future range-shifts for socio-economically valuable plant species in Europe and sub-Saharan Africa

    NASA Astrophysics Data System (ADS)

    Macias Fauria, M.; Willis, K. J.

    2011-12-01

    Bioclimatic Envelope Models (BEMs) for a set of socio-economically important tree species in Europe were independently validated using a hindcasting approach and fossil pollen records spanning the last 1000 years, including the Medieval Warm Period (MWP), the Little Ice Age (LIA) and the 20th Century warming (PRES). The aim was to determine the accuracy of combining BEMs and palaeoecological data to predict continental-scale changes in distribution, and the availability of fossil data to hindcast economically important species. Eight types of BEMs were implemented in this study, covering most state-of-the-art modelling techniques. Present and palaeoclimatic data were obtained from the Atmosphere-Ocean Global Circulation Model ECHO-G. Last millenium was divided into three climatically distinct periods: MWP (AD 900-1300), LIA (AD 1600-1850) and PRES (AD 1900-2000). Models were calibrated for each period and validated with climatic and pollen data from the remaining periods. Successfully validated models were projected onto a 1-degree European grid, allowing the reconstruction of past modelled species distributions. BEMs were successfully validated with independent data. Strong model performance suggested high potential for BEMs to be used to model future species distributions, and highlighted the importance of palaeoecological data to independently validate these models, taking into account the scales at which this data operates. Although valid, BEMs showed poorer performance with species heavily managed and/or growing in heterogeneous terrain or with discontinuous distributions. Last millennium in Europe was characterized by an increase of crop woody species and a decline of forest species, suggesting an increasing land use by humans. The same approach was then implemented to a set of sub-Saharan plant species of high importance as a source of food, wood, and other ecosystem services such as carbon storage or erosion protection. The African study covered most of the

  18. Neuroinformatics of the Allen Mouse Brain Connectivity Atlas.

    PubMed

    Kuan, Leonard; Li, Yang; Lau, Chris; Feng, David; Bernard, Amy; Sunkin, Susan M; Zeng, Hongkui; Dang, Chinh; Hawrylycz, Michael; Ng, Lydia

    2015-02-01

    The Allen Mouse Brain Connectivity Atlas is a mesoscale whole brain axonal projection atlas of the C57Bl/6J mouse brain. Anatomical trajectories throughout the brain were mapped into a common 3D space using a standardized platform to generate a comprehensive and quantitative database of inter-areal and cell-type-specific projections. This connectivity atlas has several desirable features, including brain-wide coverage, validated and versatile experimental techniques, a single standardized data format, a quantifiable and integrated neuroinformatics resource, and an open-access public online database (http://connectivity.brain-map.org/). Meaningful informatics data quantification and comparison is key to effective use and interpretation of connectome data. This relies on successful definition of a high fidelity atlas template and framework, mapping precision of raw data sets into the 3D reference framework, accurate signal detection and quantitative connection strength algorithms, and effective presentation in an integrated online application. Here we describe key informatics pipeline steps in the creation of the Allen Mouse Brain Connectivity Atlas and include basic application use cases.

  19. Galactic Plane SETI Observations with the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Backus, P. R.; Tarter, J. C.; Davis, M. M.; Jordan, J. C.; Kilsdonk, T. N.; Shostak, G. S.; Ackerman, R.; DeBoer, D. R.; Dreher, J. W.; Harp, G. R.; Ross, J. E.; Stauduhar, R.

    2005-12-01

    In the spring of 2006, the Allen Telescope Array (ATA), a joint effort of the U.C. Berkeley Radio Astronomy Lab and the SETI Institute, will begin initial operations. Starting with 42 antennas out of a planned 350, the array will be equivalent to a single 40 meter dish. Using three phased beams, we will survey twenty square degrees around the galactic center for narrowband signals in the frequency range from 1410 to 1730 MHz (the "Water Hole"). Comparison of results from the beams will be used to eliminate signals from terrestrial and satellite sources. At these frequencies, the wide field of view of the array allows us to cover the 2 x 10 degree strip with five antenna positions. The field of view will track one of the five positions for up to five hours, while the phased beams are pointed within the field of view for 98 seconds per 20 MHz frequency band. During these SETI observations spanning approximately seven months, other radio astronomy observations of this very interesting region will run in parallel using two other independently tunable IF systems with a correlator and other phase array beams feeding other backend processors. Construction of the ATA is supported by private funding, primarily from the Paul G. Allen Foundation. The correlator for the ATA is supported by NSF Grant AST-0322309 to the UCB Radio Astronomy Lab.

  20. Fossil-energy program. Progress report for June 1981

    SciTech Connect

    Not Available

    1981-08-01

    This report - the eighty-third of series - is a compendium of monthly progress reports for the ORNL research and development programs that are in support of the increased utilization of coal and other fossil fuel alternatives as sources of clean energy. The projects reported this month include those for coal conversion development, chemical research and development, materials technology, component development and process evaluation, technical support to major liquefaction projects, process analysis and engineering evaluations, fossil energy environmental analysis, flue gas desulfurization, coal preparation waste utilization, atmospheric fluidized bed coal combustor for cogeneration, TVA FBC demonstration plant program technical support, PFBC systems analysis, fossil fuel applications assessments, performance assurance system support for fossil energy projects, international energy technology assessment, generalized equilibrium models for liquid and gaseous fuel supplies, analyses of coal production goals, and fossil energy information center.

  1. Abstracts: Eighth Annual Conference on Fossil Energy Materials. Fossil Energy Program

    SciTech Connect

    Not Available

    1994-07-01

    Abstracts are presented for about 40 papers. The Fossil Energy Advanced Research and Technology Development Materials program is an integrated materials research activity of the fossil energy coal program, whose objective is to conduct R and D for all advanced coal conversion and utilization technologies. The program is aimed at understanding materials behavior in coal system environments and the development of new materials for improving plant operations and reliability. A generic approach is used for addressing multiple coal technologies; for example, the hot-gas particulate filter development is applicable to pressurized fluidized bed combustion, integrated coal gasification combined-cycle, coal combustion, and indirectly fired combined-cycle systems.

  2. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 4: Energy from fossil fuels

    NASA Technical Reports Server (NTRS)

    Williams, J. R.

    1974-01-01

    The conversion of fossil-fired power plants now burning oil or gas to burn coal is discussed along with the relaxation of air quality standards and the development of coal gasification processes to insure a continued supply of gas from coal. The location of oil fields, refining areas, natural gas fields, and pipelines in the U.S. is shown. The technologies of modern fossil-fired boilers and gas turbines are defined along with the new technologies of fluid-bed boilers and MHD generators.

  3. Astronauts Gardner and Allen during loading of Westar VI in payload bay

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Joseph P. Allen IV, top, hangs onto a stinger device as Astronaut Dale A. Gardner in the cargo bay of Discovery waits to assist in the berthing of the previously stranded satellite. The end effector of the remote manipulator system (RMS), controlled from inside the Discovery'S cabin, grasps a special grapple point to Allen's right.

  4. Astronaut Andrew M. Allen, mission commander, sets up systems for a television downlink on the

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-75 ONBOARD VIEW --- Astronaut Andrew M. Allen, mission commander, sets up systems for a television downlink on the flight deck of the Space Shuttle Columbia. Allen was joined by four other astronauts and an international payload specialist for more than 16 days of research aboard Columbia. The photograph was taken with a 70mm handheld camera.

  5. Q & A with Ed Tech Leaders: Interview with Michael W. Allen

    ERIC Educational Resources Information Center

    Shaughnessy, Michael F.

    2014-01-01

    Michael W. Allen, the Chairman and CEO of Allen Interactions, is an architect of interactive multimedia learning and is recognized for his many insights, inventions, and presentations. With over 50 years of experience in e-learning, both in academic and corporate settings, he is known for his role in creating Authorware and overseeing the work of…

  6. Allen Ivey: Pioneer in Counseling Theory and Practice, and Crusader for Multiculturalism and Social Justice

    ERIC Educational Resources Information Center

    Santiago-Rivera, Azara L.

    2009-01-01

    This article reviews the groundbreaking work of Dr. Allen Ivey through a personal interview and conversations with Mary Bradford Ivey, including a number of colleagues and former students. Allen's enormous contribution to the counseling profession spans nearly four decades. Although best known for microcounseling skills, which is widely taught in…

  7. Meeting the Challenge of Intermolecular Gold(I)-Catalyzed Cycloadditions of Alkynes and Allenes

    PubMed Central

    Muratore, Michael E; Homs, Anna; Obradors, Carla; Echavarren, Antonio M

    2014-01-01

    The development of gold(I)-catalyzed intermolecular carbo- and hetero-cycloadditions of alkynes and allenes has been more challenging than their intramolecular counterparts. Here we review, with a mechanistic perspective, the most fundamental intermolecular cycloadditions of alkynes and allenes with alkenes. PMID:25048645

  8. Carbon isotopes from fossil packrat pellets and elevational movements of Utah agave plants reveal the Younger Dryas cold period in Grand Canyon, Arizona

    USGS Publications Warehouse

    Cole, K.L.; Arundel, S.T.

    2005-01-01

    Carbon isotopes in rodent fecal pellets were measured on packrat (Neotoma spp.) middens from the Grand Canyon, Arizona. The pellet samples reflect the abundance of cold-intolerant C4 and Crassulacean acid metabolism (CAM) plant species relative to the predominant C3 vegetation in the packrat diet. The temporal sequence of isotopic results suggests a temperature decline followed by a sharp increase corresponding to the B??lling/Aller??d-Younger Dryas - early Holocene sequence. This pattern was then tested using the past distribution of Utah agave (Agave utahensis). Spatial analyses of the range of this temperature-sensitive CAM species demonstrate that its upper elevational limit is controlled by winter minimum temperature. Applying this paleotemperature proxy to the past elevational limits of Utah agave suggests that minimum winter temperatures were ???8??C below modern values during the Last Glacial Maximum, 4.5-6.5 ??C below modern during the B??lling/Aller??d, and 7.5-8.7 ??C below modern during the early Younger Dryas. As the Younger Dryas terminated, temperatures warmed ???4 ??C between ca. 11.8 ka and 11.5 ka. These extreme fluctuations in winter minimum temperature have not been generally accepted for terrestrial paleoecological records from the arid southwestern United States, likely because of large statistical uncertainties of older radiocarbon results and reliance on proxies for summer temperatures, which were less affected. ?? 2005 Geological Society of America.

  9. Carbon isotopes from fossil packrat pellets and elevational movements of Utah agave plants reveal the Younger Dryas cold period in Grand Canyon, Arizona

    NASA Astrophysics Data System (ADS)

    Cole, Kenneth L.; Arundel, Samantha T.

    2005-09-01

    Carbon isotopes in rodent fecal pellets were measured on packrat (Neotoma spp.) middens from the Grand Canyon, Arizona. The pellet samples reflect the abundance of cold-intolerant C4 and Crassulacean acid metabolism (CAM) plant species relative to the predominant C3 vegetation in the packrat diet. The temporal sequence of isotopic results suggests a temperature decline followed by a sharp increase corresponding to the Bølling/ Allerød Younger Dryas early Holocene sequence. This pattern was then tested using the past distribution of Utah agave (Agave utahensis). Spatial analyses of the range of this temperature-sensitive CAM species demonstrate that its upper elevational limit is controlled by winter minimum temperature. Applying this paleotemperature proxy to the past elevational limits of Utah agave suggests that minimum winter temperatures were ˜8 °C below modern values during the Last Glacial Maximum, 4.5 6.5 °C below modern during the Bølling/Allerød, and 7.5 8.7 °C below modern during the early Younger Dryas. As the Younger Dryas terminated, temperatures warmed ˜4 °C between ca. 11.8 ka and 11.5 ka. These extreme fluctuations in winter minimum temperature have not been generally accepted for terrestrial paleoecological records from the arid southwestern United States, likely because of large statistical uncertainties of older radiocarbon results and reliance on proxies for summer temperatures, which were less affected.

  10. Cycles in fossil diversity

    SciTech Connect

    Rohde, Robert A.; Muller, Richard A.

    2004-10-20

    It is well-known that the diversity of life appears to fluctuate during the course the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0-542 Ma). Using Sepkoski's compendium of the first and last stratigraphic appearances of 36380 marine genera, we report a strong 62 {+-} 3 Myr cycle, which is particularly strong in the shorter-lived genera. The five great extinctions enumerated by Raup and Sepkoski may be an aspect of this cycle. Because of the high statistical significance, we also consider contributing environmental factors and possible causes.

  11. Biodesulfurization of fossil fuels.

    PubMed

    Gray, Kevin A; Mrachko, Gregory T; Squires, Charles H

    2003-06-01

    Biotechnological techniques enabling the specific removal of sulfur from fossil fuels have been developed. In the past three years there have been important advances in the elucidation of the mechanisms of biodesulfurization; some of the most significant relate to the role of a flavin reductase, DszD, in the enzymology of desulfurization, and to the use of new tools that enable enzyme enhancement via DNA manipulation to influence both the rate and the substrate range of Dsz. Also, a clearer understanding of the unique desulfinase step in the pathway has begun to emerge.

  12. Cycles in fossil diversity.

    PubMed

    Rohde, Robert A; Muller, Richard A

    2005-03-10

    It is well known that the diversity of life appears to fluctuate during the course of the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0-542 million years ago). Here we show, using Sepkoski's compendium of the first and last stratigraphic appearances of 36,380 marine genera, a strong 62 +/- 3-million-year cycle, which is particularly evident in the shorter-lived genera. The five great extinctions enumerated by Raup and Sepkoski may be an aspect of this cycle. Because of the high statistical significance we also consider the contributions of environmental factors, and possible causes.

  13. Fossil evidence of water lilies (Nymphaeales) in the Early Cretaceous.

    PubMed

    Friis, E M; Pedersen, K R; Crane, P R

    2001-03-15

    Phylogenetic analyses have identified the water lilies (Nymphaeales: Cabombaceae and Nymphaeaceae), together with four other small groups of flowering plants (the 'ANITA clades': Amborellaceae, Illiciales, Trimeniaceae, Austrobaileyaceae), as the first diverging lineages from the main branch of the angiosperm phylogenetic tree, but evidence of these groups in the earliest phases of the angiosperm fossil record has remained elusive. Here we report the earliest unequivocal evidence, based on fossil floral structures and associated pollen, of fossil plants related to members of the ANITA clades. This extends the history of the water lilies (Nymphaeales) back to the Early Cretaceous (125-115 million years) and into the oldest fossil assemblages that contain unequivocal angiosperm stamens and carpels. This discovery adds to the growing congruence between results from molecular-based analyses of relationships among angiosperms and the palaeobotanical record. It is also consistent with previous observations that the flowers of early angiosperms were generally very small compared with those of their living relatives.

  14. Is the extremely rare Iberian endemic plant species Castrilanthemum debeauxii (Compositae, Anthemideae) a 'living fossil'? Evidence from a multi-locus species tree reconstruction.

    PubMed

    Tomasello, Salvatore; Álvarez, Inés; Vargas, Pablo; Oberprieler, Christoph

    2015-01-01

    The present study provides results of multi-species coalescent species tree analyses of DNA sequences sampled from multiple nuclear and plastid regions to infer the phylogenetic relationships among the members of the subtribe Leucanthemopsidinae (Compositae, Anthemideae), to which besides the annual Castrilanthemum debeauxii (Degen, Hervier & É.Rev.) Vogt & Oberp., one of the rarest flowering plant species of the Iberian Peninsula, two other unispecific genera (Hymenostemma, Prolongoa), and the polyploidy complex of the genus Leucanthemopsis belong. Based on sequence information from two single- to low-copy nuclear regions (C16, D35, characterised by Chapman et al. (2007)), the multi-copy region of the nrDNA internal transcribed spacer regions ITS1 and ITS2, and two intergenic spacer regions of the cpDNA gene trees were reconstructed using Bayesian inference methods. For the reconstruction of a multi-locus species tree we applied three different methods: (a) analysis of concatenated sequences using Bayesian inference (MrBayes), (b) a tree reconciliation approach by minimizing the number of deep coalescences (PhyloNet), and (c) a coalescent-based species-tree method in a Bayesian framework ((∗)BEAST). All three species tree reconstruction methods unequivocally support the close relationship of the subtribe with the hitherto unclassified genus Phalacrocarpum, the sister-group relationship of Castrilanthemum with the three remaining genera of the subtribe, and the further sister-group relationship of the clade of Hymenostemma+Prolongoa with a monophyletic genus Leucanthemopsis. Dating of the (∗)BEAST phylogeny supports the long-lasting (Early Miocene, 15-22Ma) taxonomical independence and the switch from the plesiomorphic perennial to the apomorphic annual life-form assumed for the Castrilanthemum lineage that may have occurred not earlier than in the Pliocene (3Ma) when the establishment of a Mediterranean climate with summer droughts triggered evolution towards

  15. ABSTRACTS: Seventh annual conference on fossil energy materials

    SciTech Connect

    Not Available

    1993-06-01

    Objective of the Advanced Research and Technology Development materials program is to conduct R and D on materials for fossil energy applications (coal processing, coal liquefaction, gasification, heat engines and recovery, combustion systems, fuel cells). Research is aimed at better understanding of materials in fossil energy environments and development of new materials for improvement of plant operations and reliability. Abstracts are given of 37 papers on ceramics/composites, intermetallics (iron aluminides, etc.), and advanced austenitics. (DLC)

  16. ABSTRACTS: Seventh annual conference on fossil energy materials

    SciTech Connect

    Not Available

    1993-01-01

    Objective of the Advanced Research and Technology Development materials program is to conduct R and D on materials for fossil energy applications (coal processing, coal liquefaction, gasification, heat engines and recovery, combustion systems, fuel cells). Research is aimed at better understanding of materials in fossil energy environments and development of new materials for improvement of plant operations and reliability. Abstracts are given of 37 papers on ceramics/composites, intermetallics (iron aluminides, etc.), and advanced austenitics. (DLC)

  17. Chirality Transfer in Gold(I)‐Catalysed Hydroalkoxylation of 1,3‐Disubstituted Allenes

    PubMed Central

    Webster, Stacey; Sutherland, Daniel R.

    2016-01-01

    Abstract Gold(I)‐catalysed intermolecular hydroalkoxylation of enantioenriched 1,3‐disubstituted allenes was previously reported to occur with poor chirality transfer due to rapid allene racemisation. The first intermolecular hydroalkoxylation of allenes with efficient chirality transfer is reported here, exploiting conditions that suppress allene racemisation. A full substrate scope study reveals that excellent regio‐ and stereoselectivities are achieved when a σ‐withdrawing substituent is present. PMID:27862422

  18. Fossil Microorganisms in Archaean

    NASA Technical Reports Server (NTRS)

    Astafleva, Marina; Hoover, Richard; Rozanov, Alexei; Vrevskiy, A.

    2006-01-01

    Ancient Archean and Proterozoic rocks are the model objects for investigation of rocks comprising astromaterials. The first of Archean fossil microorganisms from Baltic shield have been reported at the last SPIE Conference in 2005. Since this confeence biomorphic structures have been revealed in Archean rocks of Karelia. It was determined that there are 3 types of such bion structures: 1. structures found in situ, in other words microorganisms even-aged with rock matrix, that is real Archean fossils biomorphic structures, that is to say forms inhabited early formed rocks, and 3. younger than Archean-Protherozoic minerali microorganisms, that is later contamination. We made attempt to differentiate these 3 types of findings and tried to understand of burial of microorganisms. The structures belongs (from our point of view) to the first type, or real Archean, forms were under examination. Practical investigation of ancient microorganisms from Green-Stone-Belt of Northern Karelia turns to be very perspective. It shows that even in such ancient time as Archean ancient diverse world existed. Moreover probably such relatively highly organized cyanobacteria and perhaps eukaryotic formes existed in Archean world.

  19. Ion spectral structures observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Ferradas, C.; Zhang, J.; Spence, H. E.; Kistler, L. M.; Larsen, B.; Reeves, G. D.; Skoug, R. M.; Funsten, H. O.

    2015-12-01

    During the last decades several missions have recorded the presence of dynamic spectral features of energetic ions in the inner magnetosphere. Previous studies have reported single "nose-like" structures occurring alone and simultaneous nose-like structures (up to three). These ion structures are named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. They constitute the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. The HOPE mass spectrometer onboard the Van Allen Probes measures energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet, where these ion structures are observed. We present a statistical study of nose-like structures, using 2-years measurements from the HOPE instrument. The results provide important details about the spatial distribution (dependence on geocentric distance), spectral features of the structures (differences among species), and geomagnetic conditions under which these structures occur.

  20. New Cooled Feeds for the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Welch, Wm. J.; Fleming, Matthew; Munson, Chris; Tarter, Jill; Harp, G. R.; Spencer, Robert; Wadefalk, Niklas

    2017-04-01

    We developed a new generation of low-noise, broadband feeds for the Allen Telescope Array at the Hat Creek Observatory in Northern California. The new feeds operate over the frequency range 0.9 to 14 GHz. The noise temperatures of the feeds have been substantially improved by cooling the entire feed structure as well as the low-noise amplifiers to 70 K. To achieve this improved performance, the new feeds are mounted in glass vacuum bottles with plastic lenses that maximize the microwave transmission through the bottles. Both the cooled feeds and their low-noise amplifiers produce total system temperatures that are in the range 25–30 K from 1 GHz to 5 GHz and 40–50 K up to 12.5 GHz.

  1. Van Allen Probe Charging During the St. Patrick's Day Event

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Minow, J. I.

    2015-01-01

    The geomagnetic storms on and around March 17, 2015 marked the largest storms seen in the declining phase of the solar cycle to date. We use the Helium Oxygen Proton Electron (HOPE) mass spectrometer on board the Van Allen Probe - A and B satellites to study in detail the charging effects seen on these spacecraft during this time. Ion particle flux data provides information on the magnitude of the charging events using the ion line charging signature due to low energy ions accelerated by the spacecraft potential. Electron flux observations are used to correlate the charging environment with variations in spacecraft potential through the event. We also investigate the density and temperature of ions and electrons during the time of the charging event.

  2. Van Allen Probe Charging During the St. Patrick's Day Event

    NASA Astrophysics Data System (ADS)

    Parker, L. N.; Minow, J. I.

    2015-12-01

    The geomagnetic storms on and around March 17, 2015 marked the largest storms seen in the declining phase of the solar cycle to date. We use the Helium Oxygen Proton Electron (HOPE) mass spectrometer on board the Van Allen Probe - A and B satellites to study in detail the charging effects seen on these spacecraft during this time. Ion particle flux data provides information on the magnitude of the charging events using the ion line charging signature due to low energy ions accelerated by the spacecraft potential. Electron flux observations are used to correlate the charging environment with variations in spacecraft potential through the event. We also investigate the density and temperature of ions and electrons during the time of the charging event.

  3. Radioactivity in fossils at the Hagerman Fossil Beds National Monument.

    PubMed

    Farmer, C Neal; Kathren, Ronald L; Christensen, Craig

    2008-08-01

    Since 1996, higher than background levels of naturally occurring radioactivity have been documented in both fossil and mineral deposits at Hagerman Fossil Beds National Monument in south-central Idaho. Radioactive fossil sites occur primarily within an elevation zone of 900-1000 m above sea level and are most commonly found associated with ancient river channels filled with sand. Fossils found in clay rich deposits do not exhibit discernable levels of radioactivity. Out of 300 randomly selected fossils, approximately three-fourths exhibit detectable levels of natural radioactivity ranging from 1 to 2 orders of magnitude above ambient background levels when surveyed with a portable hand held Geiger-Muller survey instrument. Mineral deposits in geologic strata also show above ambient background levels of radioactivity. Radiochemical lab analysis has documented the presence of numerous natural radioactive isotopes. It is postulated that ancient groundwater transported radioactive elements through sand bodies containing fossils which precipitated out of solution during the fossilization process. The elevated levels of natural radioactivity in fossils may require special precautions to ensure that exposures to personnel from stored or displayed items are kept as low as reasonably achievable (ALARA).

  4. Clean Fossil Energy Conversion Processes

    NASA Astrophysics Data System (ADS)

    Fan, L.-S.

    2007-03-01

    Absolute and per-capita energy consumption is bound to increase globally, leading to a projected increase in energy requirements of 50% by 2020. The primary source for providing a majority of the energy will continue to be fossil fuels. However, an array of enabling technologies needs to be proven for the realization of a zero emission power, fuel or chemical plants in the near future. Opportunities to develop new processes, driven by the regulatory requirements for the reduction or elimination of gaseous and particulate pollutant abound. This presentation describes the chemistry, reaction mechanisms, reactor design, system engineering, economics, and regulations that surround the utilization of clean coal energy. The presentation will cover the salient features of the fundamental and process aspects of the clean coal technologies in practice as well as in development. These technologies include those for the cleaning of SO2, H2S, NOx, and heavy metals, and separation of CO2 from the flue gas or the syngas. Further, new combustion and gasification processes based on the chemical looping concepts will be illustrated in the context of the looping particle design, process heat integration, energy conversion efficiency, and economics.

  5. A simple approach to separate a mixture of homopropargylic and allenic alcohols.

    PubMed

    Fu, Fan; Hoang, Kim Le Mai; Loh, Teck-Peng

    2008-08-21

    A simple and practical approach to separate homopropargylic alcohol from allenic alcohol has been developed. It involves the formation of an insoluble silver acetylide species between silver nitrate and homopropargylic alcohol in aqueous acetone which can be separated from the allenic alcohol through a simple filtration. The homopropargylic alcohol can subsequently be recovered by hydrolysis with 1 N HCl. This protocol has been applied to the separation of a mixture of chiral homopropargylic and allenic alcohols in excellent yields with retention of absolute stereochemistry.

  6. Orion GNC Mitigation Efforts for Van Allen Radiation

    NASA Technical Reports Server (NTRS)

    King, Ellis T.; Jackson, Mark

    2013-01-01

    The Orion Crew Module (CM) is NASA's next generation manned space vehicle, scheduled to return humans to lunar orbit in the coming decade. The Orion avionics and GN&C architectures have progressed through a number of project phases and are nearing completion of a major milestone. The first unmanned test mission, dubbed "Exploration Flight Test One" (EFT-1) is scheduled to launch from NASA Kennedy Space Center late next year and provides the first integrated test of all the vehicle systems, avionics and software. The EFT-1 mission will be an unmanned test flight that includes a high speed re-entry from an elliptical orbit, which will be launched on an expendable launch vehicle (ELV). The ELV will place CM and the ELV upper stage into a low Earth orbit (LEO) for one revolution. After the first LEO, the ELV upper stage will re-ignite and place the combined upper stage/CM into an elliptical orbit whose perigee results in a high energy entry to test CM response in a relatively high velocity, high heating environment. While not producing entry velocities as high as those experienced in returning from a lunar orbit, the trajectory was chosen to provide higher stresses on the thermal protection and guided entry systems, as compared against a lower energy LEO entry. However the required entry geometry with constraints on inclination and landing site result in a trajectory that lingers for many hours in the Van Allen radiation belts. This exposes the vehicle and avionics to much higher levels of high energy proton radiation than a typical LEO or lunar trajectory would encounter. As a result, Van Allen radiation poses a significant risk to the Orion avionics system, and particularly the Flight Control Module (FCM) computers that house the GN&C flight software. The measures taken by the Orion GN&C, Flight Software and Avionics teams to mitigate the risks associated with the Van Allen radiation on EFT-1 are covered in the paper. Background on the Orion avionics subsystem is

  7. Organic molecules as chemical fossils - The molecular fossil record

    NASA Technical Reports Server (NTRS)

    Eglinton, G.

    1983-01-01

    The study of biochemical clues to the early earth and the origin of life is discussed. The methods used in such investigation are described, including the extraction, fractionation, and analysis of geolipids and the analysis of kerogen. The occurrence of molecular fossils in the geological record is examined, discussing proposed precursor-product relationships and the molecular assessment of deep sea sediments, ancient sediments, and crude petroleums. Alterations in the molecular record due to diagenesis and catagenesis are considered, and the use of microbial lipids as molecular fossils is discussed. The results of searches for molecular fossils in Precambrian sediments are assessed.

  8. Fossil Leaves and Fossil Leaf n-Alkanes: Reconstructing the First Closed Canopied Rainforests

    NASA Astrophysics Data System (ADS)

    Graham, H. V.; Freeman, K. H.

    2013-12-01

    Although the age and location is disputed, the rise of the first closed-canopy forest is likely linked with the expansion of angiosperms in the late Cretacous or early Cenozoic. The carbon isotope 'canopy effect' reflects the extent of canopy closure, and is well documented in δ13C values of the leaves and leaf lipids in modern forests. To test the extent of canopy closure among the oldest documented angiosperm tropical forests, we analyzed isotopic characteristics of leaf fossils and leaf waxes from the Guaduas and Cerrejón Formations. The Guaduas Fm. (Maastrichtian) contains some of the earliest angiosperm fossils in the Neotropics, and both leaf morphology and pollen records at this site suggest an open-canopy structure. The Cerrejón Fm. (Paleocene) contains what are believed to be the first recorded fossil leaves from a closed-canopy forest. We analyzed the bulk carbon isotope content (δ13Cleaf) of 199 fossil leaves, as well as the n-alkane concentration and chain-length distribution, and δ13C of alkanes (δ13Clipid) of 73 fossil leaves and adjacent sediment samples. Fossil leaves are dominated by eudicots and include ten modern plant families (Apocynaceae, Bombaceae, Euphorbaceae, Fabaceae, Lauraceae, Malvaceae, Meliaceae, Menispermaceae, Moraceae, Sapotaceae). We interpreted extent of canopy coverage based on the range of δ13Cleaf values. The narrow range of δ13C values in leaves from the Guaduas Fm (2.7‰) is consistent with an open canopy. A significantly wider range in values (6.3‰) suggests a closed-canopy signature for site 0315 of the Cerrejón Fm,. In contrast, at Site 0318, a lacustrine deposit, leaves had a narrow range (3.3‰) in δ13C values, and this is not consistent with a closed-canopy, but is consistent with leaf assemblages from a forest edge. Leaves that accumulate in lake sediments tend to be biased toward plants living at the lake edge, which do not experience closed-canopy conditions, and do not express the isotopic

  9. Fossil Energy Advanced Research and Technology Development (AR&TD) Materials Program semiannual progress report for the period ending September 30, 1991. Fossil Energy Program

    SciTech Connect

    Judkins, R.R.; Cole, N.C.

    1992-04-01

    The objective of the Fossil Energy Advanced Research and Technology Development Materials Program is to conduct research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The Program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. Research is outlined in four areas: Ceramics, New Alloys, Corrosion and Erosion Research, and Technology Development and Transfer. (VC)

  10. Gold(I)-catalysed synthesis of cyclic sulfamidates by intramolecular allene hydroamination.

    PubMed

    Higginbotham, Mari C M; Bebbington, Magnus W P

    2012-08-07

    Six-membered cyclic sulfamidates are prepared in high yields by treatment of allenic sulfamates with readily available gold(I) complexes. The reaction enables formation of N-substituted quaternary centres and complements existing processes for sulfamidate formation.

  11. Meniscus root refixation technique using a modified Mason-Allen stitch.

    PubMed

    Lee, Dhong Won; Jang, Suk Hwan; Ha, Jeong Ku; Kim, Jin Goo; Ahn, Jin Hwan

    2013-03-01

    A complete posterior medial meniscus root tear results in the inability to withstand hoop stress and requires the repair of the posterior medial meniscus root. Several techniques to repair the posterior medial meniscus root have been proposed, but most techniques are based on simple stitching. A modified Mason-Allen technique, recognized as a superior stitching method to repair rotator cuff in shoulder surgery, was applied to overcome the potential weakness of those simple stitching techniques. This newly modified Mason-Allen technique reproduces the locking effect of a conventional modified Mason-Allen stitch allowing the physiological meniscal extrusion. The purpose of this article is to describe a posterior root repair technique using a modified Mason-Allen stitch with two strands consisting of a simple horizontal and a simple vertical stitch. Level of evidence V.

  12. [Book review] Green engineering: environmentally conscious design, by David T. Allen and David R. Shonnard

    USGS Publications Warehouse

    Boustany, R.G.

    2002-01-01

    Review of: Green engineering: Environmentally conscious design / David T. Allen and David R. Shonnard / Prentice-Hall, Inc., One Lake Street, Upper Saddle River, NJ 07458. 2002. 552 pages. ISBN 0-13-061908-6.

  13. Wave acceleration of electrons in the Van Allen radiation belts.

    PubMed

    Horne, Richard B; Thorne, Richard M; Shprits, Yuri Y; Meredith, Nigel P; Glauert, Sarah A; Smith, Andy J; Kanekal, Shrikanth G; Baker, Daniel N; Engebretson, Mark J; Posch, Jennifer L; Spasojevic, Maria; Inan, Umran S; Pickett, Jolene S; Decreau, Pierrette M E

    2005-09-08

    The Van Allen radiation belts are two regions encircling the Earth in which energetic charged particles are trapped inside the Earth's magnetic field. Their properties vary according to solar activity and they represent a hazard to satellites and humans in space. An important challenge has been to explain how the charged particles within these belts are accelerated to very high energies of several million electron volts. Here we show, on the basis of the analysis of a rare event where the outer radiation belt was depleted and then re-formed closer to the Earth, that the long established theory of acceleration by radial diffusion is inadequate; the electrons are accelerated more effectively by electromagnetic waves at frequencies of a few kilohertz. Wave acceleration can increase the electron flux by more than three orders of magnitude over the observed timescale of one to two days, more than sufficient to explain the new radiation belt. Wave acceleration could also be important for Jupiter, Saturn and other astrophysical objects with magnetic fields.

  14. THE ALLEN TELESCOPE ARRAY SEARCH FOR ELECTROSTATIC DISCHARGES ON MARS

    SciTech Connect

    Anderson, Marin M.; Siemion, Andrew P. V.; Bower, Geoffrey C.; De Pater, Imke; Barott, William C.; Delory, Gregory T.; Werthimer, Dan

    2012-01-01

    The Allen Telescope Array was used to monitor Mars between 2010 March 9 and June 2, over a total of approximately 30 hr, for radio emission indicative of electrostatic discharge. The search was motivated by the report from Ruf et al. of the detection of non-thermal microwave radiation from Mars characterized by peaks in the power spectrum of the kurtosis, or kurtstrum, at 10 Hz, coinciding with a large dust storm event on 2006 June 8. For these observations, we developed a wideband signal processor at the Center for Astronomy Signal Processing and Electronics Research. This 1024 channel spectrometer calculates the accumulated power and power-squared, from which the spectral kurtosis is calculated post-observation. Variations in the kurtosis are indicative of non-Gaussianity in the signal, which can be used to detect variable cosmic signals as well as radio frequency interference (RFI). During the three-month period of observations, dust activity occurred on Mars in the form of small-scale dust storms; however, no signals indicating lightning discharge were detected. Frequent signals in the kurtstrum that contain spectral peaks with an approximate 10 Hz fundamental were seen at both 3.2 and 8.0 GHz, but were the result of narrowband RFI with harmonics spread over a broad frequency range.

  15. Ion nose spectral structures observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Ferradas, C. P.; Zhang, J.-C.; Spence, H. E.; Kistler, L. M.; Larsen, B. A.; Reeves, G.; Skoug, R.; Funsten, H.

    2016-12-01

    We present a statistical study of nose-like structures observed in energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet. Nose structures are spectral features named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. Using 22 months of observations from the Helium Oxygen Proton Electron instrument onboard Van Allen Probe A, we determine the number of noses observed, and the minimum L shell reached and energy of each nose on each pass through the inner magnetosphere. We find that multiple noses occur more frequently in heavy ions than in H+ and are most often observed during quiet times. The heavy-ion noses penetrate to lower L shells than H+ noses, and there is an energy-magnetic local time (MLT) dependence in the nose locations and energies that is similar for all species. The observations are interpreted by using a steady state model of ion drift in the inner magnetosphere. The model is able to explain the energy and MLT dependence of the different types of nose structures. Different ion charge-exchange lifetimes are the main cause for the deeper penetration of heavy-ion noses. The species dependence and preferred geomagnetic conditions of multiple-nose events indicate that they must be on long drift paths, leading to strong charge-exchange effects. The results provide important insight into the spatial distribution, species dependence, and geomagnetic conditions under which nose structures occur.

  16. SETI Observations of Exoplanets with the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Harp, G. R.; Richards, Jon; Tarter, Jill C.; Dreher, John; Jordan, Jane; Shostak, Seth; Smolek, Ken; Kilsdonk, Tom; Wilcox, Bethany R.; Wimberly, M. K. R.; Ross, John; Barott, W. C.; Ackermann, R. F.; Blair, Samantha

    2016-12-01

    We report radio SETI observations on a large number of known exoplanets and other nearby star systems using the Allen Telescope Array (ATA). Observations were made over about 19000 hr from 2009 May to 2015 December. This search focused on narrowband radio signals from a set totaling 9293 stars, including 2015 exoplanet stars and Kepler objects of interest and an additional 65 whose planets may be close to their habitable zones. The ATA observations were made using multiple synthesized beams and an anticoincidence filter to help identify terrestrial radio interference. Stars were observed over frequencies from 1 to 9 GHz in multiple bands that avoid strong terrestrial communication frequencies. Data were processed in near-real time for narrowband (0.7-100 Hz) continuous and pulsed signals with transmitter/receiver relative accelerations from -0.3 to 0.3 m s-2. A total of 1.9 × 108 unique signals requiring immediate follow-up were detected in observations covering more than 8 × 106 star-MHz. We detected no persistent signals from extraterrestrial technology exceeding our frequency-dependent sensitivity threshold of 180-310 × 10-26 W m-2.

  17. Active and passive microwave measurements in Hurricane Allen

    NASA Technical Reports Server (NTRS)

    Delnore, V. E.; Bahn, G. S.; Grantham, W. L.; Harrington, R. F.; Jones, W. L.

    1985-01-01

    The NASA Langley Research Center analysis of the airborne microwave remote sensing measurements of Hurricane Allen obtained on August 5 and 8, 1980 is summarized. The instruments were the C-band stepped frequency microwave radiometer and the Ku-band airborne microwave scatterometer. They were carried aboard a NOAA aircraft making storm penetrations at an altitude of 3000 m and are sensitive to rain rate, surface wind speed, and surface wind vector. The wind speed is calculated from the increase in antenna brightness temperature above the estimated calm sea value. The rain rate is obtained from the difference between antenna temperature increases measured at two frequencies, and wind vector is determined from the sea surface normalized radar cross section measured at several azimuths. Comparison wind data were provided from the inertial navigation systems aboard both the C-130 aircraft at 3000 m and a second NOAA aircraft (a P-3) operating between 500 and 1500 m. Comparison rain rate data were obtained with a rain radar aboard the P-3. Evaluation of the surface winds obtained with the two microwave instruments was limited to comparisons with each other and with the flight level winds. Two important conclusions are drawn from these comparisons: (1) the radiometer is accurate when predicting flight level wind speeds and rain; and (2) the scatterometer produces well behaved and consistent wind vectors for the rain free periods.

  18. Fossilization of melanosomes via sulfurization.

    PubMed

    McNamara, Maria E; van Dongen, Bart E; Lockyer, Nick P; Bull, Ian D; Orr, Patrick J

    2016-05-01

    Fossil melanin granules (melanosomes) are an important resource for inferring the evolutionary history of colour and its functions in animals. The taphonomy of melanin and melanosomes, however, is incompletely understood. In particular, the chemical processes responsible for melanosome preservation have not been investigated. As a result, the origins of sulfur-bearing compounds in fossil melanosomes are difficult to resolve. This has implications for interpretations of original colour in fossils based on potential sulfur-rich phaeomelanosomes. Here we use pyrolysis gas chromatography mass spectrometry (Py-GCMS), fourier transform infrared spectroscopy (FTIR) and time of flight secondary ion mass spectrometry (ToF-SIMS) to assess the mode of preservation of fossil microstructures, confirmed as melanosomes based on the presence of melanin, preserved in frogs from the Late Miocene Libros biota (NE Spain). Our results reveal a high abundance of organosulfur compounds and non-sulfurized fatty acid methyl esters in both the fossil tissues and host sediment; chemical signatures in the fossil tissues are inconsistent with preservation of phaeomelanin. Our results reflect preservation via the diagenetic incorporation of sulfur, i.e. sulfurization (natural vulcanization), and other polymerization processes. Organosulfur compounds and/or elevated concentrations of sulfur have been reported from melanosomes preserved in various invertebrate and vertebrate fossils and depositional settings, suggesting that preservation through sulfurization is likely to be widespread. Future studies of sulfur-rich fossil melanosomes require that the geochemistry of the host sediment is tested for evidence of sulfurization in order to constrain interpretations of potential phaeomelanosomes and thus of original integumentary colour in fossils.

  19. STS-46 Pilot Allen uses cycle ergometer on OV-104's middeck

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-46 Pilot Andrew M. Allen exercises using the cycle ergometer on the middeck of Atlantis, Orbiter Vehicle (OV) 104. Allen, shirtless, is equipped with sensors for monitoring his biological systems during the exercise session. A communications kit assembly cable freefloats from his headset at his right and in front of the forward lockers. The open airlock hatch appears at his left and the sleep station behind him.

  20. Astronauts Gardner and Allen bringing Westar VI satellite into payload bay

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Dale A. Gardner, left, and Joseph P. Allen IV work together with Dr. Anna L. Fisher (in the Discovery controlling the remote manipulator system (RMS) arm) to bring the Westar VI satellite into the Discovery's payload bay. Allen is on a mobile foot restraint, which is attached to the RMS end effector. Gardner uses the manned maneuvering unit (MMU) on the other side of the satellite. He is attempting to remove the stinger device from the now stabilized satellite.

  1. Enantioselective Terminal Addition to Allenes by Dual Chiral Primary Amine/Palladium Catalysis.

    PubMed

    Zhou, Han; Wang, Yaning; Zhang, Long; Cai, Mao; Luo, Sanzhong

    2017-03-15

    We herein describe a synergistic chiral primary amine/achiral palladium catalyzed enantioselective terminal addition to allenes with α-branched β-ketocarbonyls and aldehydes. The reactions afford allylic adducts bearing acyclic all-carbon quaternary centers with high regio- and enantioselectivity. A wide range of allenes including those aliphatic or 1,1'-disubstituted could be employed, thus expanding the scope of typical asymmetric allylic alkylation reactions.

  2. Microwave-promoted synthesis of bicyclic azocine-β-lactams from bis(allenes).

    PubMed

    Alcaide, Benito; Almendros, Pedro; Aragoncillo, Cristina; Fernández, Israel; Gómez-Campillos, Gonzalo

    2014-08-01

    A metal-free preparation of structurally novel bicyclic azocine-β-lactams has been developed. The first examples accounting for the preparation of eight-membered rings from bis(allenes) in the absence of metals have been achieved by the thermolysis of nonconjugated 2-azetidinone-tethered bis(allenes) on application of microwave irradiation. This selective carbocyclization reaction has been studied experimentally, and additionally, its mechanism has been investigated by a DFT study.

  3. STS-46 Pilot Allen, in LES, at pilots station on OV-104's forward flight deck

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-46 Pilot Andrew M. Allen, wearing launch and entry suit (LES) and launch and entry helmet (LEH), reviews descent procedural checklists while at pilots station on the forward flight deck of Atlantis, Orbiter Vehicle (OV) 104. The head-up display (HUD), flight mirror assembly, and forward windows appear in front of Allen. Control panels with drinking water containers and checklists are seen overhead.

  4. Geographical variation in bill size across bird species provides evidence for Allen's rule.

    PubMed

    Symonds, Matthew R E; Tattersall, Glenn J

    2010-08-01

    Allen's rule proposes that the appendages of endotherms are smaller, relative to body size, in colder climates, in order to reduce heat loss. Empirical support for Allen's rule is mainly derived from occasional reports of geographical clines in extremity size of individual species. Interspecific evidence is restricted to two studies of leg proportions in seabirds and shorebirds. We used phylogenetic comparative analyses of 214 bird species to examine whether bird bills, significant sites of heat exchange, conform to Allen's rule. The species comprised eight diverse taxonomic groups-toucans, African barbets, Australian parrots, estrildid finches, Canadian galliforms, penguins, gulls, and terns. Across all species, there were strongly significant relationships between bill length and both latitude and environmental temperature, with species in colder climates having significantly shorter bills. Patterns supporting Allen's rule in relation to latitudinal or altitudinal distribution held within all groups except the finches. Evidence for a direct association with temperature was found within four groups (parrots, galliforms, penguins, and gulls). Support for Allen's rule in leg elements was weaker, suggesting that bird bills may be more susceptible to thermoregulatory constraints generally. Our results provide the strongest comparative support yet published for Allen's rule and demonstrate that thermoregulation has been an important factor in shaping the evolution of bird bills.

  5. Fossilized bioelectric wire – the trace fossil Trichichnus

    PubMed Central

    Kędzierski, M.; Uchman, A.; Sawlowicz, Z.; Briguglio, A.

    2015-01-01

    The trace fossil Trichichnus is proposed as an indicator of fossil bioelectric bacterial activity at the oxic–anoxic interface zone of marine sediments. This fulfils the idea that such processes, commonly found in the modern realm, should be also present in the geological past. Trichichnus is an exceptional trace fossil due to its very thin diameter (mostly less than 1 mm) and common pyritic filling. It is ubiquitous in some fine-grained sediments, where it has been interpreted as a burrow formed deeper than any other trace fossils, below the redox boundary. Trichichnus, formerly referred to as deeply burrowed invertebrates, has been found as remnant of a fossilized intrasediment bacterial mat that is pyritized. As visualized in 3-D by means of X-ray computed microtomography scanner, Trichichnus forms dense filamentous fabric, which reflects that it is produced by modern large, mat-forming, sulfide-oxidizing bacteria, belonging mostly to Thioploca-related taxa, which are able to house a complex bacterial consortium. Several stages of Trichichnus formation, including filamentous, bacterial mat and its pyritization, are proposed to explain an electron exchange between oxic and suboxic/anoxic layers in the sediment. Therefore, Trichichnus can be considered a fossilized “electric wire”. PMID:26290671

  6. Dating Fossil Pollen: A Simulation.

    ERIC Educational Resources Information Center

    Sheridan, Philip

    1992-01-01

    Describes a hands-on simulation in which students determine the age of "fossil" pollen samples based on the pollen types present when examined microscopically. Provides instructions for the preparation of pollen slides. (MDH)

  7. The legacy of fossil fuels.

    PubMed

    Armaroli, Nicola; Balzani, Vincenzo

    2011-03-01

    Currently, over 80% of the energy used by mankind comes from fossil fuels. Harnessing coal, oil and gas, the energy resources contained in the store of our spaceship, Earth, has prompted a dramatic expansion in energy use and a substantial improvement in the quality of life of billions of individuals in some regions of the world. Powering our civilization with fossil fuels has been very convenient, but now we know that it entails severe consequences. We treat fossil fuels as a resource that anyone anywhere can extract and use in any fashion, and Earth's atmosphere, soil and oceans as a dump for their waste products, including more than 30 Gt/y of carbon dioxide. At present, environmental legacy rather than consistence of exploitable reserves, is the most dramatic problem posed by the relentless increase of fossil fuel global demand. Harmful effects on the environment and human health, usually not incorporated into the pricing of fossil fuels, include immediate and short-term impacts related to their discovery, extraction, transportation, distribution, and burning as well as climate change that are spread over time to future generations or over space to the entire planet. In this essay, several aspects of the fossil fuel legacy are discussed, such as alteration of the carbon cycle, carbon dioxide rise and its measurement, greenhouse effect, anthropogenic climate change, air pollution and human health, geoengineering proposals, land and water degradation, economic problems, indirect effects on the society, and the urgent need of regulatory efforts and related actions to promote a gradual transition out of the fossil fuel era. While manufacturing sustainable solar fuels appears to be a longer-time perspective, alternatives energy sources already exist that have the potential to replace fossil fuels as feedstocks for electricity production.

  8. Temperature of the plasmasphere from Van Allen Probes HOPE

    NASA Astrophysics Data System (ADS)

    Genestreti, K. J.; Goldstein, J.; Corley, G. D.; Farner, W.; Kistler, L. M.; Larsen, B. A.; Mouikis, C. G.; Ramnarace, C.; Skoug, R. M.; Turner, N. E.

    2017-01-01

    We introduce two novel techniques for estimating temperatures of very low energy space plasmas using, primarily, in situ data from an electrostatic analyzer mounted on a charged and moving spacecraft. The techniques are used to estimate proton temperatures during intervals where the bulk of the ion plasma is well below the energy bandpass of the analyzer. Both techniques assume that the plasma may be described by a one-dimensional E→×B→ drifting Maxwellian and that the potential field and motion of the spacecraft may be accounted for in the simplest possible manner, i.e., by a linear shift of coordinates. The first technique involves the application of a constrained theoretical fit to a measured distribution function. The second technique involves the comparison of total and partial-energy number densities. Both techniques are applied to Van Allen Probes Helium, Oxygen, Proton, and Electron (HOPE) observations of the proton component of the plasmasphere during two orbits on 15 January 2013. We find that the temperatures calculated from these two order-of-magnitude-type techniques are in good agreement with typical ranges of the plasmaspheric temperature calculated using retarding potential analyzer-based measurements - generally between 0.2 and 2 eV (2000-20,000 K). We also find that the temperature is correlated with L shell and hot plasma density and is negatively correlated with the cold plasma density. We posit that the latter of these three relationships may be indicative of collisional or wave-driven heating of the plasmasphere in the ring current overlap region. We note that these techniques may be easily applied to similar data sets or used for a variety of purposes.

  9. Ion nose spectral structures observed by the Van Allen Probes

    DOE PAGES

    Ferradas, C. P.; Zhang, J. -C.; Spence, H. E.; ...

    2016-11-22

    Here, we present a statistical study of nose-like structures observed in energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet. Nose structures are spectral features named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. Using 22 months of observations from the Helium Oxygen Proton Electron (HOPE) instrument onboard Van Allen Probe A, we determine the number of noses observed, and the minimum L-shell reached and energy of each nose on each pass through the inner magnetosphere. We find that multiple noses occur more frequentlymore » in heavy ions than in H+, and are most often observed during quiet times. The heavy-ion noses penetrate to lower L shells than H+ noses and there is an energy-magnetic local time (MLT) dependence in the nose locations and energies that is similar for all species. The observations are interpreted using a steady-state model of ion drift in the inner magnetosphere. The model is able to explain the energy and MLT dependence of the different types of nose structures. Different ion charge exchange lifetimes are the main cause for the deeper penetration of heavy-ion noses. The species dependence and preferred geomagnetic conditions of multiple-nose events indicate that they must be on long drift paths, leading to strong charge-exchange effects. The results provide important insight into the spatial distribution, species dependence, and geomagnetic conditions under which nose structures occur.« less

  10. Ion nose spectral structures observed by the Van Allen Probes

    SciTech Connect

    Ferradas, C. P.; Zhang, J. -C.; Spence, H. E.; Kistler, L. M.; Larsen, Brian Arthur; Reeves, Geoffrey D.; Skoug, Ruth M.; Funsten, Herbert O.

    2016-11-22

    Here, we present a statistical study of nose-like structures observed in energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet. Nose structures are spectral features named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. Using 22 months of observations from the Helium Oxygen Proton Electron (HOPE) instrument onboard Van Allen Probe A, we determine the number of noses observed, and the minimum L-shell reached and energy of each nose on each pass through the inner magnetosphere. We find that multiple noses occur more frequently in heavy ions than in H+, and are most often observed during quiet times. The heavy-ion noses penetrate to lower L shells than H+ noses and there is an energy-magnetic local time (MLT) dependence in the nose locations and energies that is similar for all species. The observations are interpreted using a steady-state model of ion drift in the inner magnetosphere. The model is able to explain the energy and MLT dependence of the different types of nose structures. Different ion charge exchange lifetimes are the main cause for the deeper penetration of heavy-ion noses. The species dependence and preferred geomagnetic conditions of multiple-nose events indicate that they must be on long drift paths, leading to strong charge-exchange effects. The results provide important insight into the spatial distribution, species dependence, and geomagnetic conditions under which nose structures occur.

  11. 76 FR 36318 - Safety Zone; Waterway Closure, Morgan City-Port Allen Route From Mile Marker 0 to Port Allen Lock

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... and tows from destruction, loss or injury due to hazards associated with rising flood water. DATES... the general public, levee system, vessels and tows from the hazards associated with rising flood water... hazards associated with rising flood water on the Morgan City-Port Allen Route. Basis and Purpose...

  12. Computational Research Challenges and Opportunities for the Optimization of Fossil Energy Power Generation System

    SciTech Connect

    Zitney, S.E.

    2007-06-01

    Emerging fossil energy power generation systems must operate with unprecedented efficiency and near-zero emissions, while optimizing profitably amid cost fluctuations for raw materials, finished products, and energy. To help address these challenges, the fossil energy industry will have to rely increasingly on the use advanced computational tools for modeling and simulating complex process systems. In this paper, we present the computational research challenges and opportunities for the optimization of fossil energy power generation systems across the plant lifecycle from process synthesis and design to plant operations. We also look beyond the plant gates to discuss research challenges and opportunities for enterprise-wide optimization, including planning, scheduling, and supply chain technologies.

  13. VIEW OF IRVING FLUME FROM FOSSIL SPRINGS (LINE THROUGH CENTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF IRVING FLUME FROM FOSSIL SPRINGS (LINE THROUGH CENTER OF PHOTO) AND LOCATION OF IRVING POWER PLANT (LEFT CENTER) FROM FOREST SERVICE (FS) ROAD #708 (STRAWBERRY TO IRVING). LOOKING DOWNSTREAM (SOUTH-SOUTHWEST) - Childs-Irving Hydroelectric Project, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  14. Travels with the Fossil Hunters

    NASA Astrophysics Data System (ADS)

    Whybrow, Peter J.

    2000-04-01

    Whether dodging bullets in West Africa, or rabid dogs in Pakistan, surviving yak-butter tea in Tibet, or eating raw fish in China, the life of a globe-trotting fossil hunter is often hazardous and always filled with surprises. Travels with the Fossil Hunters lets readers share the wonder, joys of discovery, and excitement of these intrepid scientists. Packed with more than 100 beautiful, full-color photographs, the volume takes readers on twelve expeditions to remote parts of the world in search of diverse fossil remains, from those of dinosaurs to human ancestors. Each expedition by paleontologists from London's Natural History Museum reveals the problems and challenges of working in extreme conditions, from the deserts of the Sahara and Yemen to the frozen wastes of Antarctica, from the mountains of India to the forests of Latvia. Along the way they also describe the paleontology and geology of the countries they visit and the scientific reasons for their expeditions. With a foreword from Sir David Attenborough and an introduction from Richard Fortey, this fascinating book will appeal to amateur and professional fossil hunters alike and to readers interested in accounts of exotic locales. Peter Whybrow is a research scientist at the Natural History Museum, London. His research interests include Arabian Miocene vertebrates, paleoclimates, paleogeography, and biotic diversity. He is senior editor with A. Hill of Fossil Vertebrates of Arabia (Yale University Press, New Haven, 1999).

  15. The early eukaryotic fossil record.

    PubMed

    Javaux, Emmanuelle J

    2007-01-01

    The Precambrian era records the evolution of the domain Eucarya. Although the taxonomy of fossils is often impossible to resolve beyond the level of domain, their morphology and chemistry indicate the evolution of major biological innovations. The late Archean record for eukaryotes is limited to trace amounts of biomarkers. Morphological evidence appears in late Paleoproterozoic and early Mesoproterozoic (1800-1300 Ma) rocks. The moderate diversity of preservable eukaryotic organisms includes cell walls without surface ornament (but with complex ultrastructure), with regularly distributed surface ornamentation, and with irregularly or regularly arranged processes. Collectively, these fossils suggest that eukaryotes with flexible membranes and cytoskeletons existed in mid-Proterozoic oceans. The late Mesoproterozoic-early Neoproterozoic (1300-750 Ma) is a time of diversification and evolution when direct evidence for important biological innovations occurs in the fossil record such as multicellularity, sex, photosynthesis, biomineralization, predation, and heterotrophy. Members of extant clades can be recognized and include bangiophyte red algae, xanthophyte algae, cladophorale green algae, euglyphid, lobose, and filose amoebae and possible fungi. In the late Neoproterozoic, besides more diversification of ornamented fossils, florideophyte red algae and brown algae diversify, and animals take the stage. The record of biological innovations documented by the fossils shows that eukaryotes had evolved most cytological and molecular complexities very early in the Proterozoic but environmental conditions delayed their diversification within clades until oxygen level and predation pressure increased significantly.

  16. Allen Brain Atlas: an integrated spatio-temporal portal for exploring the central nervous system

    PubMed Central

    Sunkin, Susan M.; Ng, Lydia; Lau, Chris; Dolbeare, Tim; Gilbert, Terri L.; Thompson, Carol L.; Hawrylycz, Michael; Dang, Chinh

    2013-01-01

    The Allen Brain Atlas (http://www.brain-map.org) provides a unique online public resource integrating extensive gene expression data, connectivity data and neuroanatomical information with powerful search and viewing tools for the adult and developing brain in mouse, human and non-human primate. Here, we review the resources available at the Allen Brain Atlas, describing each product and data type [such as in situ hybridization (ISH) and supporting histology, microarray, RNA sequencing, reference atlases, projection mapping and magnetic resonance imaging]. In addition, standardized and unique features in the web applications are described that enable users to search and mine the various data sets. Features include both simple and sophisticated methods for gene searches, colorimetric and fluorescent ISH image viewers, graphical displays of ISH, microarray and RNA sequencing data, Brain Explorer software for 3D navigation of anatomy and gene expression, and an interactive reference atlas viewer. In addition, cross data set searches enable users to query multiple Allen Brain Atlas data sets simultaneously. All of the Allen Brain Atlas resources can be accessed through the Allen Brain Atlas data portal. PMID:23193282

  17. Allen Brain Atlas: an integrated spatio-temporal portal for exploring the central nervous system.

    PubMed

    Sunkin, Susan M; Ng, Lydia; Lau, Chris; Dolbeare, Tim; Gilbert, Terri L; Thompson, Carol L; Hawrylycz, Michael; Dang, Chinh

    2013-01-01

    The Allen Brain Atlas (http://www.brain-map.org) provides a unique online public resource integrating extensive gene expression data, connectivity data and neuroanatomical information with powerful search and viewing tools for the adult and developing brain in mouse, human and non-human primate. Here, we review the resources available at the Allen Brain Atlas, describing each product and data type [such as in situ hybridization (ISH) and supporting histology, microarray, RNA sequencing, reference atlases, projection mapping and magnetic resonance imaging]. In addition, standardized and unique features in the web applications are described that enable users to search and mine the various data sets. Features include both simple and sophisticated methods for gene searches, colorimetric and fluorescent ISH image viewers, graphical displays of ISH, microarray and RNA sequencing data, Brain Explorer software for 3D navigation of anatomy and gene expression, and an interactive reference atlas viewer. In addition, cross data set searches enable users to query multiple Allen Brain Atlas data sets simultaneously. All of the Allen Brain Atlas resources can be accessed through the Allen Brain Atlas data portal.

  18. The age for the fossil-bearing Tabbowa beds in Sri Lanka

    NASA Astrophysics Data System (ADS)

    Chang, S. C.; Dassanayake, S.; Wang, J.

    2014-12-01

    Well-preserved terrestrial fossils, mainly including conifers, cycads and ferns, were discovered from the Tabbowa beds in northwestern Sri Lanka. The high diversity and abundance of plants and insects from these Jurassic sediments provide a unique window to understand floral evolution and plant-insect co-evolution in the Mesozoic. For example, unearthed fossils from the Tabbowa beds indicate that leaf feeding and dwelling insects played a significant role in the Jurassic ecosystem. For another example, feeding and chewing marks on leaves allow studying insect behavior and paleo-ecology. Additionally, the recent discoveries of Otozamites latiphyllus and Otozamites tabbowensis from these sediments provide evidence that Bennettitales, an extinct order of seed plants, widely spread in the Gondwana during the Jurassic period. Although most fossils are yet to be well studied, and only few of the fossil occurrences have been published in western journals, plant fossils from the Tabbowa beds have great potential for substantially increasing our knowledge of Jurassic terrestrial ecosystems. The fossil-bearing Tabbowa beds are mainly composed of sandstone, siltstone, and mudstone with occasional thin bands of nodular limestone. Until now, radio-isotopic age determinations for the fossil-rich Tabbowa beds are lacking. In this study, we investigate the geological and geochronological setting of this area by dating detrital zircons from the Tabbowa beds. The age data will allow testing several hypotheses regarding the plant evolution, the basin development of this region.

  19. Selective flotation of fossil resin from western coal

    SciTech Connect

    Jensen, G.F.; Miller, J.D.

    1992-03-30

    Economic analysis of this fossil resin project mainly focused on the flotation plant which is intended to be designed with data obtained from the current proof-of-concept flotation test program. It is believed that the analysis of this step is fairly accurate. The other two economic aspects of fossil in resin recovery/utilization are refining and marketing. Cost data used for refining were from an estimated base and are believed to have a large variance. Marketing data used were obtained from two independent marketing studies which were made available on confidentiality basis. Nevertheless, the data used are believed to be fairly accurate with respect to the market potential.

  20. Lipoxygenase-allene oxide synthase pathway in octocoral thermal stress response

    NASA Astrophysics Data System (ADS)

    Lõhelaid, H.; Teder, T.; Samel, N.

    2015-03-01

    Marine ecosystems are sensitive to elevated seawater temperature, with stony corals serving as model organisms for temperature-imposed declines in population viability and diversity. Several stress markers, including heat shock proteins, have been used for the detection and prediction of stress responses in stony corals. However, the stress indicators in soft corals remain elusive. In higher animals and plants, oxylipins synthesized by fatty acid di- and monooxygenases contribute to stress-induced signaling; however, the role of eicosanoid pathways in corals remains unclear. The eicosanoid gene specific to corals encodes for a natural fusion protein of allene oxide synthase and lipoxygenase ( AOS- LOX). In this work, using the easily cultivated soft coral Capnella imbricata as the stress response model, we monitored the expression of the AOS-LOX and the formation of arachidonic acid metabolites in response to an acute rise in water temperature. Gene expression profiles of two 70 kDa heat shock proteins ( Hsps: Hsp70 and Grp78) were used as a positive control for the stress response. In comparison with normal seawater temperature (23 °C), AOS- LOXa and Hsps were all up-regulated after modest (28 °C) and severe (31 °C) temperature elevation. While the up-regulation of AOS- LOXa and Grp78 was more sensitive to moderate temperature changes, Hsp70s were more responsive to severe heat shock. Concurrently, endogenous and exogenous AOS-LOXa-derived eicosanoids were up-regulated. Thus, together with the up-regulation of AOS- LOX by other abiotic and biotic stress stimuli, these data implicate AOS-LOX as part of the general stress response pathway in corals.

  1. Palaeobiology: Argentinian unhatched pterosaur fossil.

    PubMed

    Chiappe, Luis M; Codorniú, Laura; Grellet-Tinner, Gerald; Rivarola, David

    2004-12-02

    Our knowledge of the eggs and embryos of pterosaurs, the Mesozoic flying reptiles, is sparse. Until now, the recent discovery of an ornithocheirid embryo from 121-million-year-old rocks in China constituted the only reliable evidence of an unhatched pterosaur. Here we describe an embryonic fossil of a different pterosaur from the Early Cretaceous lacustrine deposits of Loma del Pterodaustro (the Lagarcito Formation, which is about 100 million years old) in central Argentina. This new fossil provides insight into the eggshell morphology, early growth and nesting environments of pterosaurs.

  2. Evaluation of conventional power systems. [emphasizing fossil fuels and nuclear energy

    NASA Technical Reports Server (NTRS)

    Smith, K. R.; Weyant, J.; Holdren, J. P.

    1975-01-01

    The technical, economic, and environmental characteristics of (thermal, nonsolar) electric power plants are reviewed. The fuel cycle, from extraction of new fuel to final waste management, is included. Emphasis is placed on the fossil fuel and nuclear technologies.

  3. Conjugate observations of quasiperiodic emissions by the Cluster, Van Allen Probes, and THEMIS spacecraft

    NASA Astrophysics Data System (ADS)

    Němec, F.; Hospodarsky, G.; Pickett, J. S.; Santolík, O.; Kurth, W. S.; Kletzing, C.

    2016-08-01

    We present results of a detailed analysis of two electromagnetic wave events observed in the inner magnetosphere at frequencies of a few kilohertz, which exhibit a quasiperiodic (QP) time modulation of the wave intensity. The events were observed by the Cluster and Van Allen Probes spacecraft and in one event also by the THEMIS E spacecraft. The spacecraft were significantly separated in magnetic local time, demonstrating a huge azimuthal extent of the events. Geomagnetic conditions at the times of the observations were very quiet, and the events occurred inside the plasmasphere. The modulation period observed by the Van Allen Probes and THEMIS E spacecraft (duskside) was in both events about twice larger than the modulation period observed by the Cluster spacecraft (dawnside). Moreover, individual QP elements occur about 15 s earlier on THEMIS E than on Van Allen Probes, which might be related to a finite propagation speed of a modulating ULF wave.

  4. Recent Results from the Relativistic Electron Proton Telescope (REPT) onboard the Van Allen Probes Mission

    NASA Astrophysics Data System (ADS)

    Kanekal, S. G.; Baker, D. N.; Elkington, S. R.; Hoxie, V. C.; Li, X.; Spence, H. E.

    2013-05-01

    We describe recent results from the REPT instruments on board Van Allen Probes mission launched on 30 August 2012. The twin spacecraft comprising the Van Allen probes mission are identically instrumented and carry a comprehensive suite of sensors characterizing magnetospheric charged particle populations, electric and magnetic fields and plasma waves. The REPT instruments comprise a well-shielded silicon solid state detector stack, with a state of the art electronics and measure electrons of ~1.5 to > 20 MeV and protons of ~17 to > 100 MeV. The instruments were commissioned 3 days after launch and continue to provide high quality measurements. We describe the Van Allen probes and the REPT instrument and report on the new and unexpected features of the outer zone electron populations observed by REPT.

  5. Space Weather data processing and Science Gateway for the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Romeo, G.; Barnes, R. J.; Weiss, M.; Fox, N. J.; Mauk, B.; Potter, M.; Kessel, R.

    2013-12-01

    A near real-time data processing pipeline for the Space Weather broadcast data from the Van Allen Probes is presented. The Van Allen Probes broadcasts a sub-set of the science data in real-time when not downlinking the principal science data. This broadcast is received by several ground stations and relayed to APL in near real time to be ingested into the space weather processing pipeline. This pipeline processes the available level zero space weather data into higher level science data products. These products are made available to the public via the Van Allen Probes Science Gateway website (http://athena.jhuapl.edu). The website acts as pivotal point though which all other instrument SOC's can be accessed. Several other data products (e.g KP/DST indices) and tools (e.g orbit calculator) are made also available to the general public.

  6. An interspecific test of allen's rule: evolutionary implications for endothermic species.

    PubMed

    Nudds, R L; Oswald, S A

    2007-12-01

    Ecogeographical rules provide potential to describe how organisms are morphologically constrained to climatic conditions. Allen's rule (relatively shorter appendages in colder environments) remains largely unsupported and there remains much controversy whether reduced surface area of appendages provides energetic savings sufficient to make this morphological trend truly adaptive. By showing for the first time that Allen's rule holds for closely related endothermic species, we provide persuasive support of the adaptive significance of this trend for multiple species. Our results indicate that reduction of thermoregulatory cost during the coldest part of the breeding season is the most likely mechanism driving Allen's rule for these species. Because for 54% of seabird species examined, rise in seasonal maximum temperature over 100 years will exceed that for minimum temperatures, an evolutionary mismatch will arise between selection for limb length reduction and ability to accommodate heat stress.

  7. Economics of scale in the production of steam with solar thermal-fossil boiler hybrid systems

    NASA Astrophysics Data System (ADS)

    Hansen, F. R.; Lindner, D. L.; Vitko, J., Jr.

    1983-03-01

    Levelized energy costs for steam plants in the size range 15 MM Btu/h to 400 MM Btu/h were estimated for steam produced by several different technologies, including stand alone oil and coal burning plants and solar central receiver fossil boiler hybrid plants. Models for the costs of plant subsystems used in these calculations are presented. Designs of the solar fossil hybrids examined were optimized for solar fraction and amount of thermal storage used by simulation of plant operation. The resulting levelized energy costs and their sensitivity to various modelling parameters are discussed.

  8. The Quaternary stratigraphy and its associated fossil fauna and flora of the Holili area, NE Tanzania

    NASA Astrophysics Data System (ADS)

    Kafumu, Peter D.; Paepe, Roland

    2003-04-01

    The basement for the Holili area (NE Tanzania) comprises gneisses of the Mozambique Belt. These rocks are overlain by a Middle Pleistocene (0.35 Ma) olivine basalt which is part of the Kilimanjaro volcanic massif. A red paleosol was formed from this basalt. This paleosol is covered successively by mudstone and calcareous tuffaceous gritty breccia. Some faunal fossil remains (bone fragments, a tooth and horns) and floral fossil remains ( angiosperm dicotyledon plant leaf impressions, twigs and wood) were discovered on the paleosol-mudstone-gritty breccia lithological boundary. The animal fossil remains were recovered from the paleosol surface while the plant fossil remains were recovered from within the mudstone that overlies the paleosol. A primitive hominid stone tool associated with chopped bones and a tooth were also discovered on the paleosol surface. The geological environment of Holili area and its associated fossil fauna and flora resembles other paleontological sites in Tanzania.

  9. A Century after Van Allen's Birth: Conclusion of Reconnaissance of Radiation Belts in the Solar System

    NASA Astrophysics Data System (ADS)

    Krimigis, S. M.

    2014-12-01

    On May 1, 1958 in the Great Hall of the US National Academy of Sciences, James A. Van Allen, having instrumented Explorer-1 and follow-on satellites with radiation detectors, announced the discovery of intense radiation at high altitudes above Earth. The press dubbed the doughnut-shaped structures "Van Allen Belts" (VAB). Soon thereafter, the search began for VAB at nearby planets. Mariner 2 flew by Venus in 1962 at a distance of 41,000 km, but no radiation was detected. The Mariner 4 mission to Mars did not observe planet-associated increase in radiation, but scaling arguments with Earth's magnetosphere yielded an upper limit to the ratio of magnetic moments of MM/ME < 0.001 (Van Allen et al, 1965). Similarly, the Mariner 5 flyby closer to Venus resulted in a ratio of magnetic moments < 0.001 (Van Allen et al, 1967), dealing a blow to the expectation that all planetary bodies must possess significant VAB. The flyby of Mercury in 1974 by Mariner 10 revealed a weak magnetic field, but the presence of durably trapped higher energy particles remained controversial until MESSENGER in 2011.The first flybys of Jupiter by Pioneers 10, 11 in 1973 and 1974, respectively, measured a plethora of energetic particles in Jupiter's magnetosphere and established the fact that their intensities were rotationally modulated. Later flybys of Jupiter and Saturn by the two Voyagers in 1979 and 1981 revealed that those magnetospheres possessed their own internal plasma source(s) and radiation belts. Subsequent discoveries of Van Allen belts at Uranus and Neptune by Voyager 2 demonstrated that VAB are the rule rather than the exception in planetary environments. We now know from the Voyagers and through Energetic Neutral Atom images from Cassini and IBEX that an immense energetic particle population surrounds the heliosphere itself. Thus, the reconnaissance of radiation belts of our solar system has been completed, some 56 years after the discovery of the Van Allen Belts at Earth.

  10. Fossil energy program. Progress report for May 1980

    SciTech Connect

    McNeese, L.E.

    1980-08-01

    This report - the seventieth of a series - is a compendium of monthly progress reports for the ORNL research and development programs that are in support of the increased utilization of coal and other fossil fuel alternatives to oil and gas as sources of clean energy. The projects reported this month include those for coal conversion development, chemical research and development, materials technology, component and process evaluation studies, technical support to major liquefaction projects, process analysis and engineering evaluations, fossil energy environmental analysis, coal preparation and waste utilization, coal preparation plant automation, technical support to the TVA fluidized bed combustion demonstration plant program, coal cogeneration/district heating plant assessment, atmospheric fluidized bed coal combustor for cogeneration, performance assurance system support and international energy technology assessment.

  11. Fossil energy program. Progress report for June 1980

    SciTech Connect

    McNeese, L.E.

    1980-08-01

    This report - the seventy-first of a series - is a compendium of monthly progress reports for the ORNL research and development programs that are in support of the increased utilization of coal and other fossil fuel alternatives to oil and gas as sources of clean energy. The projects reported this month include those for coal conversion development, chemical research and development, materials technology, component and process evaluation studies, technical support to major liquefaction projects, process analysis and engineering evaluation, fossil energy environmental analysis, coal preparation and waste utilization, coal preparation plant automation, atmospheric fluidized bed coal combustor for cogeneration, TVA fluidized combustion demonstration plant program technical support, coal cogeneration/district heating plant assessment, performance assurance system support, and international energy technology assessment.

  12. Fossil Energy Program. Progress report for April 1980

    SciTech Connect

    McNeese, L.E.

    1980-06-01

    This report - the sixty-ninth of a series - is a compendium of monthly progress reports for the ORNL research and development programs that are in support of the increased utilization of coal and other fossil fuel alternatives to oil and gas as sources of clean energy. The projects reported this month include those for coal conversion development, chemical research and development, materials technology, component and process evaluation studies, technical support to major liquefaction projects, process analysis and engineering evaluations, fossil energy environmental analysis, coal preparation and waste utilization, coal preparation plant automation, atmospheric fluidized bed coal combustor for cogeneration, technical support to the TVA fluidized bed combustion demonstration plant program, coal cogeneration/district heating plant assessment, performance assurance system support, and international energy technology assessment.

  13. Can UK fossil fuel emissions be determined by radiocarbon measurements?

    NASA Astrophysics Data System (ADS)

    Wenger, Angelina; O'Doherty, Simon; Rigby, Matthew; Manning, Alistair; Palmer, Paul

    2016-04-01

    The GAUGE project evaluates different methods to estimate UK emissions. However, estimating carbon dioxide emissions as a result of fossil fuel burning is challenging as natural fluxes in and out of the atmosphere are very large. Radiocarbon (14C) measurements offer a way to specifically measure the amount of recently added carbon dioxide from fossil fuel burning. This is possible as, due to their age, all the radiocarbon in fossil fuels has decayed. Hence the amount of recently added CO2 from fossil fuel burning can be measured as a depletion of the 14C content in air. While this method has been successfully applied by several groups on a city or a regional scale, this is the first attempt at using the technique for a national emission estimate. Geographically the UK, being an island, is a good location for such an experiment. But are 14CO2 measurements the ideal solution for estimating fossil fuel emissions as they are heralded to be? Previous studies have shown that 14CO2emissions from the nuclear industry mask the 14C depletion caused by fossil fuel burning and result in an underestimation of the fossil fuel CO2. While this might not be a problem in certain regions around the world, many countries like the UK have a substantial nuclear industry. A correction for this enhancement from the nuclear industry can be applied but are invariably difficult as 14CO2emissions from nuclear power plants have a high temporal variability. We will explain how our sampling strategy was chosen to minimize the influence form the nuclear industry and why this proved to be challenging. In addition we present the results from our ground based measurements to show why trying to estimate national emissions using radiocarbon measurements was overambitious, and how practical the technique is for the UK in general.

  14. Experiments in no-impact control of dingoes: comment on Allen et al. 2013.

    PubMed

    Johnson, Christopher N; Crowther, Mathew S; Dickman, Chris R; Letnic, Michael I; Newsome, Thomas M; Nimmo, Dale G; Ritchie, Euan G; Wallach, Arian D

    2014-02-22

    There has been much recent debate in Australia over whether lethal control of dingoes incurs environmental costs, particularly by allowing increase of populations of mesopredators such as red foxes and feral cats. Allen et al. (2013) claim to show in their recent study that suppression of dingo activity by poison baiting does not lead to mesopredator release, because mesopredators are also suppressed by poisoning. We show that this claim is not supported by the data and analysis reported in Allen et al.'s paper.

  15. Replacement of two amino acids of 9R-dioxygenase-allene oxide synthase of Aspergillus niger inverts the chirality of the hydroperoxide and the allene oxide.

    PubMed

    Sooman, Linda; Wennman, Anneli; Hamberg, Mats; Hoffmann, Inga; Oliw, Ernst H

    2016-02-01

    The genome of Aspergillus niger codes for a fusion protein (EHA25900), which can be aligned with ~50% sequence identity to 9S-dioxygenase (DOX)-allene oxide synthase (AOS) of Fusarium oxysporum, homologues of the Fusarium and Colletotrichum complexes and with over 62% sequence identity to homologues of Aspergilli, including (DOX)-9R-AOS of Aspergillus terreus. The aims were to characterize the enzymatic activities of EHA25900 and to identify crucial amino acids for the stereospecificity. Recombinant EHA25900 oxidized 18:2n-6 sequentially to 9R-hydroperoxy-10(E),12(Z)-octadecadienoic acid (9R-HPODE) and to a 9R(10)-allene oxide. 9S- and 9R-DOX-AOS catalyze abstraction of the pro-R hydrogen at C-11, but the direction of oxygen insertion differs. A comparison between twelve 9-DOX domains of 9S- and 9R-DOX-AOS revealed conserved amino acid differences, which could contribute to the chirality of products. The Gly616Ile replacement of 9R-DOX-AOS (A. niger) increased the biosynthesis of 9S-HPODE and the 9S(10)-allene oxide, whereas the Phe627Leu replacement led to biosynthesis of 9S-HPODE and the 9S(10)-allene oxide as main products. The double mutant (Gly616Ile, Phe627Leu) formed over 90% of the 9S stereoisomer of HPODE. 9S-HPODE was formed by antarafacial hydrogen abstraction and oxygen insertion, i.e., the original H-abstraction was retained but the product chirality was altered. We conclude that 9R-DOX-AOS can be altered to 9S-DOX-AOS by replacement of two amino acids (Gly616Ile, Phe627Leu) in the DOX domain.

  16. Rule Fossilization: A Tentative Model

    ERIC Educational Resources Information Center

    Vigil, Neddy A.; Oller, John W.

    1976-01-01

    A cybernetic model of factors involved in the fossilization of grammatical and lexical forms in learner grammars is offered. A distinction is made between affective and cognitive dimensions of a multidimensional channel of human communication; and the effect of expected and unexpected feedback on these two dimensions is discussed. (Author/POP)

  17. The colour of fossil feathers.

    PubMed

    Vinther, Jakob; Briggs, Derek E G; Prum, Richard O; Saranathan, Vinodkumar

    2008-10-23

    Feathers are complex integumentary appendages of birds and some other theropod dinosaurs. They are frequently coloured and function in camouflage and display. Previous investigations have concluded that fossil feathers are preserved as carbonized traces composed of feather-degrading bacteria. Here, an investigation of a colour-banded feather from the Lower Cretaceous Crato Formation of Brazil revealed that the dark bands are preserved as elongate, oblate carbonaceous bodies 1-2 microm long, whereas the light bands retain only relief traces on the rock matrix. Energy dispersive X-ray analysis showed that the dark bands preserve a substantial amount of carbon, whereas the light bands show no carbon residue. Comparison of these oblate fossil bodies with the structure of black feathers from a living bird indicates that they are the eumelanin-containing melanosomes. We conclude that most fossil feathers are preserved as melanosomes, and that the distribution of these structures in fossil feathers can preserve the colour pattern in the original feather. The discovery of preserved melanosomes opens up the possibility of interpreting the colour of extinct birds and other dinosaurs.

  18. A Critique of Mark D. Allen's "The Preservation of Verb Subcategory Knowledge in a Spoken Language Comprehension Deficit"

    ERIC Educational Resources Information Center

    Kemmerer, David

    2008-01-01

    Allen [Allen, M. (2005). "The preservation of verb subcategory knowledge in a spoken language comprehension deficit." "Brain and Language, 95", 255-264.] reports a single patient, WBN, who, during spoken language comprehension, is still able to access some of the syntactic properties of verbs despite being unable to access some of their semantic…

  19. Silencing of hydroperoxide lyase and allene oxide synthase reveals substrate and defense signaling crosstalk in Nicotiana attenuata.

    PubMed

    Halitschke, Rayko; Ziegler, Jörg; Keinänen, Markku; Baldwin, Ian T

    2004-10-01

    The fatty acid hydroperoxide (HP) substrates required for the biosynthesis of jasmonic acid (JA) and green leaf volatiles (GLVs) are supplied by separate lipoxygenases (LOX). We silenced the expression of two genes downstream of the LOX: allene oxide synthase (AOS) and HP lyase (HPL) by antisense expression of endogenous genes (NaAOS, NaHPL) in Nicotiana attenuata, in which the biosynthesis of JA is amplified by herbivore-specific elicitors. We report that these elicitors also amplify wound-induced GLV releases, but suppress the wound-induced increase of NaHPL transcripts, suggesting that substrate flux controls GLV biosynthesis. As expected, silencing of NaHPL and NaAOS reduced GLV release and JA accumulation, respectively. Surprisingly, HPL- and AOS-silenced plants had enhanced JA and GLV responses, suggesting substrate 'crosstalk' between these two oxylipin cascades. Plants with depleted GLVs (as-hpl) were less attractive than wild type (WT) or empty vector control plants in choice-tests with native lepidopteran herbivores. In feeding trials, Manduca sexta larvae developed slower on as-hpl plants. The reduced larval consumption and performance, which was not caused by increases in defense responses in as-hpl plants, could be restored to WT levels by the addition of synthetic GLVs, demonstrating that GLVs function as feeding stimulants. Gene expression profiling by cDNA microarray analysis and characterization of several induced defenses in herbivore-elicited as-hpl and as-aos plants revealed differential involvement of JA and GLVs in defense signaling. Elicitation of volatile terpenoids (an indirect defense) requires JA signaling, where as trypsin protease inhibitor elicitation (a direct defense) requires both functional JA and GLV cascades.

  20. C-isotope composition of fossil sedges and grasses

    NASA Astrophysics Data System (ADS)

    Kurschner, Wolfram M.

    2010-05-01

    C4 plants differ from C3 plants regarding their anatomy and their C-isotope composition. Both features can be used in the geological record to determine the presence of C4 plants. Yet, the evolution of the C4 pathway in the fossil record is enigmatic as palaeobotanical and geological evidence for C4 plants is sparse. The oldest structural evidence for Kranz anatomy has been found in Late Miocene permineralized grass leaf remains. But studies on the C-isotope composition of sedimentary organic matter indicate that abundant C4 biomass was present in N-America and Asia throughout the Miocene in expanding savannahs and grasslands. The success of C4 plants appears to be related also to an increasing seasonal aridity in the tropical climate belts and the co-evolution of grazers. However, C- isotope composition of palaeosols or vertebrate teeth only allows to estimate the abundance of C4 plant biomass in the vegetation or in the diet without further taxonomical specification which plant groups would have had C4 metabolism. In this contribution the first extensive C-isotope analysis of fossil seeds of sedges and a few grasses are presented. The age of the carpological material ranges from Late Eocene to Pliocene and was collected from several central European brown coal deposits. The 52 different taxa studied include several species of Carex, Cladiocarya, Eriopherum, Eleocharis, Scirpus, Sparganium. Most of them representing herbaceous elements of a (sub)tropical vegetation growing near the edge of a lake. The C-isotope composition of the fossil seeds varies between -30 and -23 o/oo indicating C3 photosynthesis. This first systematic inventory shows that C4 plants were absent in the European (sub)tropical brown coal forming wetland vegetation during the Tertiary. These preliminary data are in agreement with phylogenetic studies which predict the origin of C4 plants outside the European realm.

  1. Paleophysiology: From Fossils to the Future.

    PubMed

    Vermeij, Geerat J

    2015-10-01

    Future environments may resemble conditions that have not existed for millions of years. To assess the adaptive options available to organisms evolving under such circumstances, it is instructive to probe paleophysiology, the ways in which ancient life coped with its physical and chemical surroundings. To do this, we need reliable proxies that are based on fundamental principles, quantitatively verified in living species, and observable in fossil remains. Insights have already come from vertebrates and plants, and others will likely emerge for marine animals if promising proxies are validated. Many questions remain about the circumstances for the evolution of environmental tolerances, metabolic rates, biomineralization, and physiological responses to interacting species, and about how living organisms will perform under exceptional conditions.

  2. Hygroscopic motions of fossil conifer cones

    PubMed Central

    Poppinga, Simon; Nestle, Nikolaus; Šandor, Andrea; Reible, Bruno; Masselter, Tom; Bruchmann, Bernd; Speck, Thomas

    2017-01-01

    Conifer cones represent natural, woody compliant structures which move their scales as passive responses to changes in environmental humidity. Here we report on water-driven opening and closing motions in coalified conifer cones from the Eemian Interglacial (approx. 126,000–113,000 years BP) and from the Middle Miocene (approx. 16.5 to 11.5 million years BP). These cones represent by far the oldest documented evidence of plant parts showing full functionality of such passive hydraulically actuated motion. The functional resilience of these structures is far beyond the biological purpose of seed dispersal and protection and is because of a low level of mineralization of the fossils. Our analysis emphasizes the functional-morphological integrity of these biological compliant mechanisms which, in addition to their biological fascination, are potentially also role models for resilient and maintenance-free biomimetic applications (e.g., adaptive and autonomously moving structures including passive hydraulic actuators). PMID:28074936

  3. Hygroscopic motions of fossil conifer cones.

    PubMed

    Poppinga, Simon; Nestle, Nikolaus; Šandor, Andrea; Reible, Bruno; Masselter, Tom; Bruchmann, Bernd; Speck, Thomas

    2017-01-11

    Conifer cones represent natural, woody compliant structures which move their scales as passive responses to changes in environmental humidity. Here we report on water-driven opening and closing motions in coalified conifer cones from the Eemian Interglacial (approx. 126,000-113,000 years BP) and from the Middle Miocene (approx. 16.5 to 11.5 million years BP). These cones represent by far the oldest documented evidence of plant parts showing full functionality of such passive hydraulically actuated motion. The functional resilience of these structures is far beyond the biological purpose of seed dispersal and protection and is because of a low level of mineralization of the fossils. Our analysis emphasizes the functional-morphological integrity of these biological compliant mechanisms which, in addition to their biological fascination, are potentially also role models for resilient and maintenance-free biomimetic applications (e.g., adaptive and autonomously moving structures including passive hydraulic actuators).

  4. Hygroscopic motions of fossil conifer cones

    NASA Astrophysics Data System (ADS)

    Poppinga, Simon; Nestle, Nikolaus; Šandor, Andrea; Reible, Bruno; Masselter, Tom; Bruchmann, Bernd; Speck, Thomas

    2017-01-01

    Conifer cones represent natural, woody compliant structures which move their scales as passive responses to changes in environmental humidity. Here we report on water-driven opening and closing motions in coalified conifer cones from the Eemian Interglacial (approx. 126,000–113,000 years BP) and from the Middle Miocene (approx. 16.5 to 11.5 million years BP). These cones represent by far the oldest documented evidence of plant parts showing full functionality of such passive hydraulically actuated motion. The functional resilience of these structures is far beyond the biological purpose of seed dispersal and protection and is because of a low level of mineralization of the fossils. Our analysis emphasizes the functional-morphological integrity of these biological compliant mechanisms which, in addition to their biological fascination, are potentially also role models for resilient and maintenance-free biomimetic applications (e.g., adaptive and autonomously moving structures including passive hydraulic actuators).

  5. Fossil group origins. VII. Galaxy substructures in fossil systems

    NASA Astrophysics Data System (ADS)

    Zarattini, S.; Girardi, M.; Aguerri, J. A. L.; Boschin, W.; Barrena, R.; del Burgo, C.; Castro-Rodriguez, N.; Corsini, E. M.; D'Onghia, E.; Kundert, A.; Méndez-Abreu, J.; Sánchez-Janssen, R.

    2016-02-01

    Context. Fossil groups (FG) are expected to be the final product of galaxy merging within galaxy groups. In simulations, they are predicted to assemble their mass at high redshift. This early formation allows for the innermost M∗ galaxies to merge into a massive central galaxy. Then, they are expected to maintain their fossil status because of the few interactions with the large-scale structure. In this context, the magnitude gap between the two brightest galaxies of the system is considered a good indicator of its dynamical status. As a consequence, the systems with the largest gaps should be dynamically relaxed. Aims: In order to examine the dynamical status of these systems, we systematically analyze, for the first time, the presence of galaxy substructures in a sample of 12 spectroscopically-confirmed fossil systems with redshift z ≤ 0.25. Methods: We apply a number of tests to investigate the substructure in fossil systems in the two-dimensional space of projected positions out to R200. Moreover, for a subsample of five systems with at least 30 spectroscopically-confirmed members we also analyze the substructure in the velocity and in the three-dimensional velocity-position spaces. Additionally, we look for signs of recent mergers in the regions around the central galaxies. Results: We find that an important fraction of fossil systems show substructure. The fraction depends critically on the adopted test, since each test is more sensitive to a particular type of substructure. Conclusions: Our interpretation of the results is that fossil systems are not, in general, as relaxed as expected from simulations. Our sample of 12 spectroscopically-confirmed fossil systems need to be extended to compute an accurate fraction, but our conclusion is that this fraction is similar to the fraction of substructure detected in nonfossil clusters. This result points out that the magnitude gap alone is not a good indicator of the dynamical status of a system. However, the

  6. A Biological Time Capsule. Fossil Fish.

    ERIC Educational Resources Information Center

    Dolph, Gary E.; Dolph, Laura L.

    1990-01-01

    Described is an activity where students prepare high-quality fossil specimens to demonstrate the theory of evolution. The technique needed for fossil removal, the geologic and paleoclimatic setting, and the fish morphology are discussed. (KR)

  7. Viroids: "living fossils" of primordial RNAs?

    PubMed

    Diener, Theodor O

    2016-03-25

    The discovery of the viroid in 1971, which initiated the third major expansion of the biosphere towards smaller living entities-after discovery of the "subvisual" microorganisms in 1675 and that of the "submicroscopic" viruses in 1892-has been officially endorsed by the International Committee on Virus Taxonomy as a new order called subviral agents.In 1989, I proposed that, based on their respective molecular properties, viroids are more plausible "living fossils" of the hypothetical RNA World (widely assumed to have existed prior to the evolution of DNA or proteins) than are intron-derived RNAs, which were, at that time, suggested as putative survivors. There were few citations of my proposal-and virtually none of viroids-beyond plant virology unil 1994, when Cheles-Flores critically examined the hypothesis and pointed out a serious difficulty, as well as a process by which this difficulty could be overcome. In 2013, when investigations by Koonin and Dolja revealed that of extant RNAs, viroids "strikingly" display some of the molecular properties posited for the earliest evolving, selfish RNAs (primordial RNAs), but, because extant organisms, aside from higher plants, appear not to harbor viroids, they cannot be regarded as primordial fossils, but appear to have evolved post LUCA (the Last Universal Common Ancestor). Here, I review whether some evidence nevertheless is compatible with the original postulate of the 1989 hypothesis. My analysis reveals no unequivocal evidence for an ancient origin of viroids, but suggests, alternatively, that viroids may have evolved de novo more recently, probably by novel processes similar to those suggested by each reviewer.These results are important, because they help illuminate a little understood period of abiogenesis--after the abiotic synthesis of life's chemical building blocks, which is, in principle, understood, and before the evolution of DNA and proteins in the late RNA World.

  8. Regioselective Allene Hydrosilylation Catalyzed by NHC Complexes of Nickel and Palladium

    PubMed Central

    Miller, Zachary D.; Li, Wei; Belderrain, Tomás R.; Montgomery, John

    2013-01-01

    Regioselective methods for allene hydrosilylation have been developed, with regioselectivity being governed primarily by choice of metal. Alkenylsilanes are produced via nickel catalysis with larger N-heterocyclic carbene ligands, and allylsilanes are produced via palladium catalysis with smaller N-heterocyclic carbene ligands. These complementary methods allow either regioisomeric product to be obtained with exceptional regiocontrol. PMID:24079389

  9. Phosphorus-Containing Bis-allenes: Synthesis and Heterocyclization Reactions Mediated by Iodine or Copper Dibromide.

    PubMed

    Essid, I; Laborde, C; Legros, F; Sevrain, N; Touil, S; Rolland, M; Ayad, T; Volle, J-N; Pirat, J-L; Virieux, D

    2017-03-30

    Bisphosphorylallenes were easily obtained in multigram scale from the Wittig-type rearrangement of bispropargyl alcohols. Unlike other conjugated bis-allenes, these reagents underwent a double cyclization mediated by iodine or copper dibromide leading to the formation of bis-1,2-oxaphospholenes.

  10. No Radio Flaring Detected from Cygnus X-3 at 3 GHz by Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Williams, P. K. G.; Bower, G. C.; Tomsick, J. A.; Bodaghee, A.; Corbet, R. H. D.

    2011-01-01

    Following the announcement of a 98 GHz flare from the microquasar Cygnus X-3 (ATel #3130), we observed it with the Allen Telescope Array (Welch et al., 2009 Proc. IEEE 97 1438 for 2.5 hours beginning at 2011 January 28.848 UT (MJD 55589.848), about 4.0 hours after the 98 GHz observations concluded.

  11. Astronauts Gardner and Allen on the RMS after recapture of Westar VI

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Dale A. Gardner, left, holds a 'For Sale' sign, making light reference to the status of the recaptured communications satellite. Astronaut Joseph P. ALlen IV stands on the mobile foot restraint (MFR), which in tandem with the remote manipulator system (RMS) arm served as a cherry-picker for capture efforts.

  12. Astronauts Gardner and Allen during loading of Palapa B-2 in payload bay

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Joseph P. Allen IV, left, tethered to the orbiting Discovery, holds onto the Palapa B-2 satellite with his right hand while Astronaut Dale A. Gardner returns the used 'stinger' device to its stowage area. The payload bay is open, showing the area where the satellite will be stowed for the return to Earth.

  13. All Together Now: Valerie Allen--U.S. Department of Energy

    ERIC Educational Resources Information Center

    Library Journal, 2005

    2005-01-01

    When Valerie Allen decided she did not want to be a Montessori teacher any longer, she began work on her MLIS. Immediately she learned concepts she could apply to her new job as information specialist for the Department of Energy's (DOE) Office of Scientific and Technical Information (OSTI) at Oak Ridge National Laboratory, TN. While the LIS…

  14. Free Pulp Transfer for Fingertip Reconstruction—The Algorithm for Complicated Allen Fingertip Defect

    PubMed Central

    Spyropoulou, Georgia-Alexandra; Shih, Hsiang-Shun

    2015-01-01

    Abstract Background: We present a review of all the cases of free toe pulp transfer and an algorithm for application of free pulp transfer in complicated Allen fingertip defect. Methods: Seventeen patients underwent free toe pulp transfer for fingertip reconstruction by the senior author. Twelve cases were Allen type II with oblique pulp defect, 4 were Allen type III, and 1 patient had 2 fingertip injuries classified both as type IV. According to the algorithm presented, for the type III defects where the germinal matrix is still preserved, we use free pulp transfer and nail bed graft to preserve the nail growth instead of toe to hand transfer. For the type IV injuries with multiple defects, a combination of web flap from both big toe and second toe is possible for 1-stage reconstruction. Results: All pulp flaps survived completely. Static 2-point discrimination ranged from 6 to 15 mm (mean: 10.5 mm). No patient presented dysesthesia, hyperesthesia, pain at rest, or cold intolerance. The donor site did not present any nuisances apart from partial skin graft loss in 3 cases. Conclusions: We tried to classify and modify the defects’ reconstruction according to Allen classification. Free toe pulp transfer is a “like with like” reconstruction that provides sensate, glabrous skin with good color and texture match for fingertip trauma, and minimal donor site morbidity compared with traditional toe to hand transfer. PMID:26894009

  15. Astronauts Joseph Allen rides cherry picker over stowage area/work station

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Joseph P. Allen rides a cherry picker over to a stowage area/work station to wrap up extravehicular activity (EVA) duties above Earth. The cherry picker is a union of the mobile foot restraint and the remote manipulator system (RMS), controlled from inside Discovery's cabin. The Westar VI/PAM-D satellite is pictured secured in Discovery's cargo bay.

  16. Precipitation of relativistic electrons of the Van Allen belts into the proton aurora

    SciTech Connect

    Jordanova, Vania K; Miyoshi, Y; Sakaguchi, K; Shiokawa, K; Evans, D S; Connors, M

    2008-01-01

    The Van Allen electron belts consist of two regions encircling the earth in which relativistic electrons are trapped in the earth's magnetic field. Populations of relativistic electrons in the Van Allen belts vary greatly with geomagnetic disturbance and they are a major source of damage to space vehicles. In order to know when and by how much these populations of relativistic electrons increase, it is important to elucidate not only the cause of acceleration of relativistic electrons but also the cause of their loss from the Van Allen belts. Here we show the first evidence that left-hand polarized electromagnetic ion cyclotron (EMIC) plasma waves can cause the loss of relativistic electrons into the atmosphere, on the basis of results of an excellent set of ground and satellite observations showing coincident precipitation of ions with energies of tens of keV and of relativistic electrons into an isolated proton aurora. The proton aurora was produced by precipitation of ions with energies of tens of keV due to EMIC waves near the plasma pause, which is a manifestation of wave-particle interactions. These observations clarify that ions with energies of tens of keV affect the evolution of relativistic electrons in the Van Allen belts via parasitic resonance with EMIC waves, an effect that was first theoretically predicted in the early 1970's.

  17. Looking at Fossils in New Ways

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    2005-01-01

    Existing fossils could be studied from a different prospective with the use of new methods of analysis for gathering more information. The new techniques of studying fossils binds the new and the old techniques and information and provides another way to look at fossils.

  18. New Results About the Earth’s Van Allen Radiation Belts

    NASA Astrophysics Data System (ADS)

    Baker, Daniel

    2015-01-01

    The first great scientific discovery of the Space Age was that the Earth is enshrouded in toroids, or 'belts', of very high-energy magnetically trapped charged particles. Early observations of the radiation environment clearly indicated that the Van Allen belts could be delineated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies showed that electrons in the energy range 100 keV < E< 1 MeV often populated both the inner and outer zones with a pronounced 'slot' region relatively devoid of energetic electrons existing between them. This two-belt structure for the Van Allen moderate-energy electron component was explained as being due to strong interactions of electrons with electromagnetic waves just inside the cold plasma (plasmapause) boundary. The energy distribution, spatial extent and particle species makeup of the Van Allen belts has been subsequently explored by several space missions. However, recent observations by the NASA dual-spacecraft Van Allen Probes mission have revealed wholly unexpected properties of the radiation belts, especially at highly relativistic (E > 2 MeV) and ultra-relativistic (E > 5 MeV) kinetic energies. In this presentation we show using high spatial and temporal resolution data from the Relativistic Electron-Proton Telescope (REPT) experiment on board the Van Allen Probes that multiple belts can exist concurrently and that an exceedingly sharp inner boundary exists for ultra-relativistic electrons. Using additionally available Van Allen Probes data, we demonstrate that these remarkable features of energetic electrons are not due to a physical boundary within Earth's intrinsic magnetic field. Neither is it likely that human-generated electromagnetic transmitter wave fields might produce such effects. Rather, we conclude from these unique measurements that slow natural inward radial diffusion combined with weak, but persistent, wave-particle pitch angle

  19. Clustering fossils in solid inflation

    SciTech Connect

    Akhshik, Mohammad

    2015-05-01

    In solid inflation the single field non-Gaussianity consistency condition is violated. As a result, the long tenor perturbation induces observable clustering fossils in the form of quadrupole anisotropy in large scale structure power spectrum. In this work we revisit the bispectrum analysis for the scalar-scalar-scalar and tensor-scalar-scalar bispectrum for the general parameter space of solid. We consider the parameter space of the model in which the level of non-Gaussianity generated is consistent with the Planck constraints. Specializing to this allowed range of model parameter we calculate the quadrupole anisotropy induced from the long tensor perturbations on the power spectrum of the scalar perturbations. We argue that the imprints of clustering fossil from primordial gravitational waves on large scale structures can be detected from the future galaxy surveys.

  20. FOSSIL SPRINGS ROADLESS AREA, ARIZONA.

    USGS Publications Warehouse

    Beard, L.S.; Ellis, C.E.

    1984-01-01

    Based on field studies, the Fossil Springs Roadless Area in central Arizona is concluded to have little promise for the occurrence of mineral or energy resources. Rocks in the Supai Formation (Pennsylvanian-Permian) near the central part of the roadless area contain widespread but spotty copper mineralization and trace amounts of uranium. Analyses obtained during the study define geochemical anomalies in two portions of the area that remain unexplained. The suites of anomalous metals suggest the possibility of hydrothermal veins and the presence of ultramafic rocks; neither were found in the field. Although there is little promise for the occurrence of mineral resources in the Fossil Springs Roadless Area, studies to identify the source of the geochemical anomalies could have valuable implications for regional studies and mineral exploration in the surrounding area.

  1. Extinction and the fossil record

    NASA Technical Reports Server (NTRS)

    Sepkoski, J. J. Jr; Sepkoski JJ, ,. J. r. (Principal Investigator)

    1994-01-01

    The author examines evidence of mass extinctions in the fossil record and searches for reasons for such large extinctions. Five major mass extinctions eliminated at least 40 percent of animal genera in the oceans and from 65 to 95 percent of ocean species. Questions include the occurrence of gradual or catastrophic extinctions, causes, environment, the capacity of a perturbation to cause extinctions each time it happens, and the possibility and identification of complex events leading to a mass extinction.

  2. New Optical Sensor Suite for Ultrahigh Temperature Fossil Fuel Application

    SciTech Connect

    John Coggin; Tom Flynn; Jonas Ivasauskas; Daniel Kominsky; Carrie Kozikowski; Russell May; Michael Miller; Tony Peng; Gary Pickrell; Raymond Rumpf; Kelly Stinson-Bagby; Dan Thorsen; Rena Wilson

    2007-12-31

    Accomplishments of a program to develop and demonstrate photonic sensor technology for the instrumentation of advanced powerplants and solid oxide fuel cells are described. The goal of this project is the research and development of advanced, robust photonic sensors based on improved sapphire optical waveguides, and the identification and demonstration of applications of the new sensors in advanced fossil fuel power plants, where the new technology will contribute to improvements in process control and monitoring.

  3. Spectroscopic studies of wood fossils from the Crato Formation, Cretaceous Period.

    PubMed

    da Silva, J H; Freire, P T C; Abagaro, B T O; Silva, J A F; Saraiva, G D; de Lima, F J; Barros, O A; Bantim, R A; Saraiva, A A F; Viana, B C

    2013-11-01

    In this work we study two types of wood fossils (Gymnosperms, Araucariaceae) from the Crato Formation of Araripe Basin in Brazil, from the Cretaceous Period. The samples were characterized by Raman and infrared spectroscopies, X-ray diffraction and scanning electron microscopy. The results obtained by different techniques showed that although the rocks surrounding the fossils have predominantly the same constitution - calcite - however, the formation processes of these types of wood fossils are quite different. One of the fossils, denominated as light wood, is predominantly composed of gypsum, while the other fossil, the dark wood, is rich in amorphous carbon, possibly the kerogen type. Implications relative to the environment where the plants lived millions years ago are also given. Finally, the results highlight the constitution of one of the most important paleontological sites of the Cretaceous Period in the South America.

  4. THE NATURE OF FOSSIL GALAXY GROUPS: ARE THEY REALLY FOSSILS?

    SciTech Connect

    La Barbera, F.; Sorrentino, G.; De Carvalho, R. R.; De la Rosa, I. G.; Gal, R. R.; Kohl-Moreira, J. L.

    2009-04-15

    We use SDSS-DR4 photometric and spectroscopic data out to redshift z {approx} 0.1 combined with ROSAT All Sky Survey X-ray data to produce a sample of 25 fossil groups (FGs), defined as bound systems dominated by a single, luminous elliptical galaxy with extended X-ray emission. We examine possible biases introduced by varying the parameters used to define the sample, and the main pitfalls are also discussed. The spatial density of FGs, estimated via the V/V {sub MAX} test, is 2.83 x 10{sup -6} h {sup 3} {sub 75} Mpc{sup -3} for L{sub X} > 0.89 x 10{sup 42} h {sup -2} {sub 75} erg s{sup -1} consistent with Vikhlinin et al., who examined an X-ray overluminous elliptical galaxy sample (OLEG). We compare the general properties of FGs identified here with a sample of bright field ellipticals generated from the same data set. These two samples show no differences in the distribution of neighboring faint galaxy density excess, distance from the red sequence in the color-magnitude diagram, and structural parameters such as a {sub 4} and internal color gradients. Furthermore, examination of stellar populations shows that our 25 FGs have similar ages, metallicities, and {alpha}-enhancement as the bright field ellipticals, undermining the idea that these systems represent fossils of a physical mechanism that occurred at high redshift. Our study reveals no difference between FGs and field ellipticals, suggesting that FGs might not be a distinct family of true fossils, but rather the final stage of mass assembly in the universe.

  5. Determination of fossil carbon content in Swedish waste fuel by four different methods.

    PubMed

    Jones, Frida C; Blomqvist, Evalena W; Bisaillon, Mattias; Lindberg, Daniel K; Hupa, Mikko

    2013-10-01

    This study aimed to determine the content of fossil carbon in waste combusted in Sweden by using four different methods at seven geographically spread combustion plants. In total, the measurement campaign included 42 solid samples, 21 flue gas samples, 3 sorting analyses and 2 investigations using the balance method. The fossil carbon content in the solid samples and in the flue gas samples was determined using (14)C-analysis. From the analyses it was concluded that about a third of the carbon in mixed Swedish waste (municipal solid waste and industrial waste collected at Swedish industry sites) is fossil. The two other methods (the balance method and calculations from sorting analyses), based on assumptions and calculations, gave similar results in the plants in which they were used. Furthermore, the results indicate that the difference between samples containing as much as 80% industrial waste and samples consisting of solely municipal solid waste was not as large as expected. Besides investigating the fossil content of the waste, the project was also established to investigate the usability of various methods. However, it is difficult to directly compare the different methods used in this project because besides the estimation of emitted fossil carbon the methods provide other information, which is valuable to the plant owner. Therefore, the choice of method can also be controlled by factors other than direct determination of the fossil fuel emissions when considering implementation in the combustion plants.

  6. Enantioselective Synthesis of 5,7-Bicyclic Ring Systems from Axially Chiral Allenes Using a Rh(I)-Catalyzed Cyclocarbonylation Reaction

    PubMed Central

    Grillet, Francois; Brummond, Kay M.

    2013-01-01

    A transfer of chirality in an intramolecular Rh(I)-catalyzed allenic Pauson-Khand reaction (APKR) to access tetrahydroazulenones, tetrahydrocyclopenta[c]azepinones and dihydrocyclopenta[c]oxepinones enantioselectively (22 – 99% ee) is described. The substitution pattern of the allene affected the transfer of chiral information. Complete transfer of chirality was obtained for all trisubstituted allenes, but loss of chiral information was observed for disubstituted allenes. This work constitutes the first demonstration of a transfer of chiral information from an allene to the 5-position of a cyclopentenone using a cyclocarbonylation reaction. The absolute configuration of the corresponding cyclocarbonylation product was also established, something that is rarely done. PMID:23485149

  7. Fossil evidence for the early ant evolution

    NASA Astrophysics Data System (ADS)

    Perrichot, Vincent; Lacau, Sébastien; Néraudeau, Didier; Nel, André

    2008-02-01

    Ants are one of the most studied insects in the world; and the literature devoted to their origin and evolution, systematics, ecology, or interactions with plants, fungi and other organisms is prolific. However, no consensus yet exists on the age estimate of the first Formicidae or on the origin of their eusociality. We review the fossil and biogeographical record of all known Cretaceous ants. We discuss the possible origin of the Formicidae with emphasis on the most primitive subfamily Sphecomyrminae according to its distribution and the Early Cretaceous palaeogeography. And we review the evidence of true castes and eusociality of the early ants regarding their morphological features and their manner of preservation in amber. The mid-Cretaceous amber forest from south-western France where some of the oldest known ants lived, corresponded to a moist tropical forest close to the shore with a dominance of gymnosperm trees but where angiosperms (flowering plants) were already diversified. This palaeoenvironmental reconstruction supports an initial radiation of ants in forest ground litter coincident with the rise of angiosperms, as recently proposed as an ecological explanation for their origin and successful evolution.

  8. Geoscience Outreach Activity Using Art to Understand Imprint Fossils Engaging K-5 Students

    NASA Astrophysics Data System (ADS)

    Derrick, E. R.

    2015-12-01

    In order to engage students in grades 3 through 5 in the geosciences, a hands on science activity was developed and implemented using art as a mechanism to gain knowledge of imprint fossils. The desired learning outcomes of this activity were for students to understand imprint fossils formation and how these fossils can be used to learn about past organisms. For more advanced students, an additional learning outcome was to understand how fossils provide information about depositional environments. Five graduate and undergraduate student volunteers presented imprint fossils and used a game to connect the fossils with the corresponding organisms. Students then made their own imprint fossils using modeling clay, plants, and plastic dinosaur skeletons. Of the 212 participating students, 95% (201) of students completed the hands on activity successfully and reported a knowledge gain in the formation and significance of imprint fossils. The activity was adapted to accommodate a diverse student population across grade and ability levels. Classroom teachers reported incorporating students' art into further classroom learning and requested this activity to be repeated the following year by the outreach group.

  9. Electron acceleration in the heart of the Van Allen radiation belts.

    PubMed

    Reeves, G D; Spence, H E; Henderson, M G; Morley, S K; Friedel, R H W; Funsten, H O; Baker, D N; Kanekal, S G; Blake, J B; Fennell, J F; Claudepierre, S G; Thorne, R M; Turner, D L; Kletzing, C A; Kurth, W S; Larsen, B A; Niehof, J T

    2013-08-30

    The Van Allen radiation belts contain ultrarelativistic electrons trapped in Earth's magnetic field. Since their discovery in 1958, a fundamental unanswered question has been how electrons can be accelerated to such high energies. Two classes of processes have been proposed: transport and acceleration of electrons from a source population located outside the radiation belts (radial acceleration) or acceleration of lower-energy electrons to relativistic energies in situ in the heart of the radiation belts (local acceleration). We report measurements from NASA's Van Allen Radiation Belt Storm Probes that clearly distinguish between the two types of acceleration. The observed radial profiles of phase space density are characteristic of local acceleration in the heart of the radiation belts and are inconsistent with a predominantly radial acceleration process.

  10. Automated determination of electron density from electric field measurements on the Van Allen Probes spacecraft

    NASA Astrophysics Data System (ADS)

    Zhelavskaya, Irina; Kurth, William; Spasojevic, Maria; Shprits, Yuri

    2016-07-01

    We present the Neural-network-based Upper-hybrid Resonance Determination (NURD) algorithm for automatic inference of the electron number density from plasma wave measurements made onboard NASA's Van Allen Probes mission. A feedforward neural network is developed to determine the upper hybrid resonance frequency, f_{uhr}, from electric field measurements, which is then used to calculate the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few attempts to do robust, routine automated detections. We describe the design and implementation of the algorithm and perform an initial analysis of the resulting electron number density distribution obtained by applying NURD to 2.5 years of data collected with the EMFISIS instrumentation suite of the Van Allen Probes mission. Densities obtained by NURD are compared to those obtained by another recently developed automated technique and also to an existing empirical plasmasphere and trough density model.

  11. Cycloaddition reactions of allenes with N-phenylmaleimide. A two-step, diradical-intermediate process

    SciTech Connect

    Pasto, D.J.; Heid, P.F.; Warren, S.E.

    1982-06-30

    The stereoselectivities, chemoselectivities, relative reactivities, and kinetic isotope effects have been determined in the cycloaddition reactions of substituted allenes with N-phenylmaleimide. The comparison of these results with those derived from the studies of the cycloaddition of 1,1-dichloro-2,2-difluoroethene and the radical-chain addition of benzenethiol to allenes strongly indicates that the cycloadditions with N-phenylmaleimide occur via a two-step, diradical-intermediate process. The stereochemical features controlling the formation of the stereoisomeric diradical intermediates and their ring closures are discussed. In addition to the cycloaddition processes, competitive ene reactions occur to produce intermediate dienes, which react further to produce 1:2 adducts or nonreactive alkyne-containing 1:1 adducts. These ene reactions also appear to proceed via diradical intermediates.

  12. Fossil energy program. Summary document

    SciTech Connect

    1980-05-01

    This program summary document presents a comprehensive overview of the research, development, and demonstration (RD and D) activities that will be performed in FY 1981 by the Assistant Secretary for Fossil Energy (ASFE), US Department of Energy (DOE). The ASFE technology programs for the fossil resources of coal, petroleum (including oil shale) and gas have been established with the goal of making substantive contributions to the nation's future supply and efficienty use of energy. On April 29, 1977, the Administration submitted to Congress the National Energy Plan (NEP) and accompanying legislative proposals designed to establish a coherent energy policy structure for the United States. Congress passed the National Energy Act (NEA) on October 15, 1978, which allows implementation of the vital parts of the NEP. The NEP was supplemented by additional energy policy statements culminating in the President's address on July 15, 1979, presenting a program to further reduce dependence on imported petroleum. The passage of the NEA-related energy programs represent specific steps by the Administration and Congress to reorganize, redirect, and clarify the role of the Federal Government in the formulation and execution of national energy policy and programs. The energy technology RD and D prog4rams carried out by ASFE are an important part of the Federal Government's effort to provide the combination and amounts of energy resources needed to ensure national security and continued economic growth.

  13. The two last overviews by Colin Allen Wraight (1945-2014) on energy conversion in photosynthetic bacteria.

    PubMed

    Maróti, Péter; Govindjee

    2016-02-01

    Colin Allen Wraight (1945-2014) was a well-known biophysicist and biochemist of our times-formerly Professor of Biochemistry, Biophysics and Plant Biology, and Head of the Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA. (See a detailed Tribute to him by Govindjee et al., Photosynth Res, 2015.) During the latter part of his life, Colin had (1) given an excellent lecture in 2008 on the overall topic of the molecular mechanisms in biological energy conversion, focusing on how an ubiquinone is reduced to ubiquinol at the so-called "two electron gate", and (2) presented a review poster on the design features of long distance proton transport in biological systems, with focus on photosynthetic bacteria (a pdf file of the original is available from one of us, Govindjee). We present here for historical purpose, a complete transcript of his 2008 lecture and his 2013 poster, which have been annotated and expanded by the authors of this paper. The major theme is: electron and proton transfer in biological systems, with emphasis on bacterial reaction centers. The figures, some of which were prepared by us, are presented in sequence for both the lecture and the poster. A common bibliography is provided at the end of the paper, which is divided into two parts: (I) The Lecture; and (II) The Poster.

  14. An Archeological Overview and Management Plan for the Lima Army Tank Plant, Allen County, Ohio.

    DTIC Science & Technology

    1985-03-11

    American, uroamerican, and uropear. cultures; adaptations by American farmers to local environments and to regional and national economic and political...French and English trade in the area on Native American, Ruroamerican, and European cultures; (3) adaptations by American Tradition farmers to the...Harold, David Asch , Nancy Asch , Edwin Hajic, David Morgan, and Michael Spitzer. 1981. Archeological Reconnaissance of a Proposed Soyland Power

  15. Ruthenium Catalyzed Reductive Coupling of Paraformaldehyde to Trifluoromethyl Allenes: CF3-Bearing All-Carbon Quaternary Centers

    PubMed Central

    Sam, Brannon; Montgomery, T. Patrick; Krische, Michael J.

    2013-01-01

    Trifluoromethyl substituted allenes engage in ruthenium catalyzed reductive couplings with paraformaldehyde to form products of hydrohydroxymethylation as single regioisomers. This method enables generation of CF3-bearing all-carbon quaternary stereocenters. PMID:23841678

  16. A critique of Mark D. Allen's "the preservation of verb subcategory knowledge in a spoken language comprehension deficit".

    PubMed

    Kemmerer, David

    2008-07-01

    Allen [Allen, M. (2005). The preservation of verb subcategory knowledge in a spoken language comprehension deficit. Brain and Language, 95, 255-264.] reports a single patient, WBN, who, during spoken language comprehension, is still able to access some of the syntactic properties of verbs despite being unable to access some of their semantic properties. Allen claims that these findings challenge linguistic theories which assume that much of the syntactic behavior of verbs can be predicted from their meanings. I argue, however, that this conclusion is not supported by the data for two reasons: first, Allen focuses on aspects of verb syntax that are not claimed to be influenced by verb semantics; and second, he ignores aspects of verb syntax that are claimed to be influenced by verb semantics.

  17. Enantioselective and Regiodivergent Addition of Purines to Terminal Allenes: Synthesis of Abacavir.

    PubMed

    Thieme, Niels; Breit, Bernhard

    2017-02-01

    The rhodium-catalyzed atom-economic asymmetric N-selective intermolecular addition of purine derivatives to terminal allenes is reported. Branched allylic purines were obtained in high yields, regioselectivity and outstanding enantioselectivity utilizing a Rh/Josiphos catalyst. Conversely, linear selective allylation of purines could be realized in good to excellent regio- and E/Z-selectivity with a Pd/dppf catalyst system. Furthermore, the new methodology was applied to a straightforward asymmetric synthesis of carbocyclic nucleoside abacavir.

  18. Van Allen Probes observations of electromagnetic ion cyclotron waves triggered by enhanced solar wind dynamic pressure

    NASA Astrophysics Data System (ADS)

    Cho, J.-H.; Lee, D.-Y.; Noh, S.-J.; Shin, D.-K.; Hwang, J.; Kim, K.-C.; Lee, J. J.; Choi, C. R.; Thaller, S.; Skoug, R.

    2016-10-01

    Magnetospheric compression due to impact of enhanced solar wind dynamic pressure Pdyn has long been considered as one of the generation mechanisms of electromagnetic ion cyclotron (EMIC) waves. With the Van Allen Probe-A observations, we identify three EMIC wave events that are triggered by Pdyn enhancements under prolonged northward interplanetary magnetic field (IMF) quiet time preconditions. They are in contrast to one another in a few aspects. Event 1 occurs in the middle of continuously increasing Pdyn while Van Allen Probe-A is located outside the plasmapause at postmidnight and near the equator (magnetic latitude (MLAT) -3°). Event 2 occurs by a sharp Pdyn pulse impact while Van Allen Probe-A is located inside the plasmapause in the dawn sector and rather away from the equator (MLAT 12°). Event 3 is characterized by amplification of a preexisting EMIC wave by a sharp Pdyn pulse impact while Van Allen Probe-A is located outside the plasmapause at noon and rather away from the equator (MLAT -15°). These three events represent various situations where EMIC waves can be triggered by Pdyn increases. Several common features are also found among the three events. (i) The strongest wave is found just above the He+ gyrofrequency. (ii) The waves are nearly linearly polarized with a rather oblique propagation direction ( 28° to 39° on average). (iii) The proton fluxes increase in immediate response to the Pdyn impact, most significantly in tens of keV energy, corresponding to the proton resonant energy. (iv) The temperature anisotropy with T⊥ > T|| is seen in the resonant energy for all the events, although its increase by the Pdyn impact is not necessarily always significant. The last two points (iii) and (iv) may imply that in addition to the temperature anisotropy, the increase of the resonant protons must have played a critical role in triggering the EMIC waves by the enhanced Pdyn impact.

  19. Astronauts Gardner and Allen during loading of Palapa B-2 in payload bay

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Joseph P. Allen, in this frame, is the sole anchor for the top portion (and most of) the captured Palapa B-2 satellite. Astronaut Dale A. Gardner is on the other end as they load it into the payload bay. Note the difference between the two stinger devices stowed on the Challenger's port side (right side of frame). The one nearer the spacecraft's vertical stabilizer is spent. The one nearer the camera is still awaiting use.

  20. Whistler-Mode Waves inside Density Ducts Observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Rosborough, S.; Bengtson, M.; Stein, R. L.; Streltsov, A. V.

    2015-12-01

    The Van Allen Probes satellites launched by NASA in 2012 are currently orbiting in Earth's radiation belts collecting data about electromagnetic waves and charged particles in the near-earth space environment. Whistler-mode waves are naturally occurring right-hand polarized, very-low frequency waves (< 30 kHz), that can efficiently interact with the energetic electrons in the earth's radiation belts magnetosphere and remediate them from the magnetosphere by precipitating these particles into the atmosphere. The important property of the whistler-mode waves is that they can be guided by density inhomogeneities extended along the ambient magnetic field and localized in the direction perpendicular to the field. Such density channels can be formed by the density enhancement or depletion and they are called ducts. The primary goal of our research is to find density duct and whistler waves in the data recorded by the Van Allen Probes satellites in the magnetosphere, and to reproduce these data with numerical simulations of time-dependent, two-dimensional electron MHD model. In this paper, we present results from our analysis of the observations performed by the Van Allen Probes satellites on 15 October 2014. Data from the probes show the electric and magnetic fields and plasma density. In this event whistler-mode waves were observed from 01:42 to 01:54 UT inside the localized density enhancement coincided with the flux of energetic electrons. Short time intervals, high concentrated electron density, and electron flux gradient activity make this event very interesting for the investigation. Numerical simulations of the electron MHD model revels reasonable quantitative agreement between numerical results and satellite observations, suggesting that the electromagnetic disturbances recorded by the Van Allen Probes satellites, are the whistler-mode waves indeed.

  1. Allene as the parent substrate in zinc-mediated biomimetic hydration reactions of cumulenes.

    PubMed

    Jahn, Burkhard O; Eger, Wilhelm A; Anders, Ernst

    2008-11-07

    The aim of our present investigation is to unravel the general mode of biomimetic activation of a wide variety of cumulenes by carbonic anhydrase (CA) models. Carbonic anhydrases allow the specific recognition, activation and transfer not only of CO2 but also of heteroallenes X=C=Y such as the polar or polarizable examples COS, CS2, H2CCO, and RNCS. Therefore, this enzyme class fulfils the requirements of excellent catalysts with a wide variety of important applications. Can this be extended to the isoelectronic but less reactive allene molecule, H2C=C=CH2 and extremely simplified models as mimetic concept for active center of the carbonic anhydrase? Allene is a waste product in the refinery, i.e. the C3-cut of the naphtha distillation; therefore, any addition product that can be obtained from allene in high yields will be of significant value. We investigated the complete catalytic cycle of a very simple model reaction, the hydration of allene, using density functional theory. Additionally, calculations were performed for the uncatalyzed reaction. There are two possible ways for the nucleophilic attack leading to different products. The zinc hydroxide complex and the water molecule can react at the central or the terminal carbon atoms (positional selectivity), the resulting products are 2-propen-1-ol and propen-2-ol, respectively, acetone. The calculations indicate a significant lower energy barrier for the rate determining step of the formation of propen-2-ol and therefore a well-expressed regioselectivity for the addition of such small molecules. The zinc complex has a pronounced catalytic effect and lowers the activation barrier from 262.5 to 123.9 kJ/mol compared with the uncatalyzed reaction. This work suggests the most probable paths for this reaction and discloses the necessity for the development of novel catalysts.

  2. Palladium-Catalyzed Formal (5 + 2) Annulation between ortho-Alkenylanilides and Allenes.

    PubMed

    Cendón, Borja; Casanova, Noelia; Comanescu, Cezar; García-Fandiño, Rebeca; Seoane, Andrés; Gulías, Moisés; Mascareñas, José L

    2017-04-07

    2-Alkenyltriflylanilides react with allenes upon treatment with catalytic amounts of Pd(OAc)2 and Cu(II) to give highly valuable 2,3-dihydro-1H-benzo[b]azepines, in good yields, and with very high regio- and diastereoselectivities. Density functional theory (DFT) calculations suggest that the C-H activation of the alkenylanilide involves a classical concerted metalation-deprotonation (CMD) mechanism.

  3. Nonlinear wave-particle interactions in the outer radiation belts: Van Allen Probes results

    NASA Astrophysics Data System (ADS)

    Agapitov, Oleksiy; Mozer, Forrest; Artemyev, Anton; Drake, James; Vasko, Ivan

    2016-10-01

    Huge numbers of different nonlinear structures (double layers, electron holes, non-linear whistlers, etc. referred to as Time Domain Structures - TDS) have been observed by the electric field experiment on board the Van Allen Probes. A large part of the observed non-linear structures are associated with whistler waves and some of them can be directly driven by whistlers. Observations of electron velocity distributions and chorus waves by the Van Allen Probe B provided long-lasting signatures of electron Landau resonant interactions with oblique chorus waves in the outer radiation belt. In the inhomogeneous geomagnetic field, such resonant interactions then lead to the formation of a plateau in the parallel (with respect to the geomagnetic field) velocity distribution due to trapping of electrons into the wave effective potential. The feedback from trapped particles provides steepening of parallel electric field and development of TDS seeded from initial whistler structure (well explained in terms of Particle-In-Cell model). The decoupling of the whistler wave and the nonlinear electrostatic component is shown in PIC simulation in the inhomogeneous magnetic field system and are observed by the Van Allen Probes in the radiation belts.

  4. Observation of plasma depletions in outer radiation belt by Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Lee, J.; Kim, K.; Lee, E.; Kim, Y.; Park, Y.; Parks, G. K.; Sibeck, D. G.

    2013-12-01

    Van Allen Probes (RBSP) observed plasma fine structures in the outer radiation belt during storm time on 14 November 2012. Five plasma depletion regions are clearly identified by VAP_A and VAP_B from 02:00UT to 04:45UT by particle instrument suite that can measure electrons and ions in a wide energy range, from 20 eV to 10 MeV. The plasma flux density dramatically decreases about 2 - 3 orders of magnitude in the depletion regions regardless of energy and particle species. Our analysis shows the plasma cavities are formed at the boundary of trapped and injected particle current. The total plasma pressures inside the depletion regions are much smaller than outside, implying unstable structures. It seems that this structures appear unusually only for storm main phase. During strong storm event, geomagnetic field is stretched and low plasma density region (lobe) moves to low latitude, this event could be analyzed by lobe region crossing of spacecraft. However, to explain temporal sequences of this event, we should assume large fluctuation of lobe boundary. Another possible analysis is plasma bubble generated in the tail region. The bubble model proposed to explain plasma transportation form tail to near Earth region in 1980s. While the bubble model reasonably explain the spatial and temporal structures observed by Van Allen probes, we cannot completely rule out the lobe region crossing model. In this presentation, we shall discuss about the characteristics of the plasma density cavities first observed by Van Allen Probes.

  5. Radition belt dynamics : Recent results from van Allen Probes and future observations from CeREs

    NASA Astrophysics Data System (ADS)

    Kanekal, Shrikanth; O'Brien, Paul; Baker, Daniel N.; Ogasawara, Keiichi; Fennell, Joseph; Christian, Eric; Claudepierre, Seth; Livi, Stefano; Desai, Mihir; Li, Xinlin; Jaynes, Allison; Turner, Drew; Jones, Ashley; Schiller, Quintin

    2016-07-01

    We describe recent observations of the Earth's radiation belts made by instruments on board the Van Allen Probes mission, particularly the Relativistic Electron Proton Telescope (REPT) and the Magnetic Electron Ion spectrometer (MagEIS). These observations have significantly advanced our understanding of terrestrial radiation belt dynamics. The Van Allen Probes mission comprises two identically instrumented spacecraft which were launched 31 August, 2012 into low-inclination lapping equatorial orbits. The orbit periods are about 9 hours, with perigees and apogees of of ~600 km and 5.8 RE respectively. We discuss the new scientific findings of the Van Allen Probes mission regarding the physics of energization and loss of relativistic electrons and their implications for future low-cost missions, especially CubeSats. We describe the CeREs (a Compact Radiation belt Explorer) CubeSat mission currently being built at the Goddard Space Flight Center, and carrying on board, an innovative instrument, the Miniaturized Electron Proton Telescope (MERiT). The MERiT is a compact low-mass low-power instrument measuring electrons from a few keV to tens of MeV in multiple differential channels. MERiT is optimized to measure electron microbursts with a high time resolution of a few milliseconds. We present and discuss possible future scientific contributions from CeREs.

  6. Unravelling the Complexities of the Earth's Radiation Belts: Findings from the Van Allen Probes mission

    NASA Astrophysics Data System (ADS)

    Mauk, Barry; Fox, Nicola; Kessel, Ramona; Sibeck, David; Kanekal, Shri

    2014-05-01

    Within the first year of Van Allen Probe operations, team members made a series of highly publicized decisive discoveries concerning the structure and evolution of the Earth's radiation belts, the processes that energize particles there, and the locations where they operate. Nevertheless, much more extensive and less publicized findings from the Van Allen Probes suggest that Earth's radiation belts regions remain a highly complex and puzzling place. Although the relation between magnetic storm and radiation belt enhancements and loss has been emphasized, dynamics during non-storm periods has occasionally been shown to be dramatic. While emphasis has been placed on new findings regarding local non-adiabatic energization mechanisms, adiabatic mechanisms have also been shown to be important. Furthermore, the interplay between, and relative importance of, these and other energization processes remain uncertain. The role of seed populations has been highlighted, with some studies pointing to localized mechanisms and others pointing to the role of substorms in transporting and injecting such populations. Here we review some of the less publicized findings and future objectives of the Van Allen Probes mission to get a broader and in-depth view of present understanding of Earth's inner magnetosphere.

  7. A neural network approach for identifying particle pitch angle distributions in Van Allen Probes data

    NASA Astrophysics Data System (ADS)

    Souza, V. M.; Vieira, L. E. A.; Medeiros, C.; Da Silva, L. A.; Alves, L. R.; Koga, D.; Sibeck, D. G.; Walsh, B. M.; Kanekal, S. G.; Jauer, P. R.; Rockenbach, M.; Dal Lago, A.; Silveira, M. V. D.; Marchezi, J. P.; Mendes, O.; Gonzalez, W. D.; Baker, D. N.

    2016-04-01

    Analysis of particle pitch angle distributions (PADs) has been used as a means to comprehend a multitude of different physical mechanisms that lead to flux variations in the Van Allen belts and also to particle precipitation into the upper atmosphere. In this work we developed a neural network-based data clustering methodology that automatically identifies distinct PAD types in an unsupervised way using particle flux data. One can promptly identify and locate three well-known PAD types in both time and radial distance, namely, 90° peaked, butterfly, and flattop distributions. In order to illustrate the applicability of our methodology, we used relativistic electron flux data from the whole month of November 2014, acquired from the Relativistic Electron-Proton Telescope instrument on board the Van Allen Probes, but it is emphasized that our approach can also be used with multiplatform spacecraft data. Our PAD classification results are in reasonably good agreement with those obtained by standard statistical fitting algorithms. The proposed methodology has a potential use for Van Allen belt's monitoring.

  8. Gradual Diffusion and Punctuated Phase Space Density Enhancements of Highly Relativistic Electrons: Van Allen Probes Observations

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Jaynes, A. N.; Li, X.; Henderson, M. G.; Kanekal, S. G.; Reeves, G. D.; Spence, H. E.; Claudepierre, S. G.; Fennell, J. F.; Hudson, M. K.

    2014-01-01

    The dual-spacecraft Van Allen Probes mission has provided a new window into mega electron volt (MeV) particle dynamics in the Earth's radiation belts. Observations (up to E (is) approximately 10MeV) show clearly the behavior of the outer electron radiation belt at different timescales: months-long periods of gradual inward radial diffusive transport and weak loss being punctuated by dramatic flux changes driven by strong solar wind transient events. We present analysis of multi-MeV electron flux and phase space density (PSD) changes during March 2013 in the context of the first year of Van Allen Probes operation. This March period demonstrates the classic signatures both of inward radial diffusive energization and abrupt localized acceleration deep within the outer Van Allen zone (L (is) approximately 4.0 +/- 0.5). This reveals graphically that both 'competing' mechanisms of multi-MeV electron energization are at play in the radiation belts, often acting almost concurrently or at least in rapid succession.

  9. Allen Brain Atlas-Driven Visualizations: a web-based gene expression energy visualization tool.

    PubMed

    Zaldivar, Andrew; Krichmar, Jeffrey L

    2014-01-01

    The Allen Brain Atlas-Driven Visualizations (ABADV) is a publicly accessible web-based tool created to retrieve and visualize expression energy data from the Allen Brain Atlas (ABA) across multiple genes and brain structures. Though the ABA offers their own search engine and software for researchers to view their growing collection of online public data sets, including extensive gene expression and neuroanatomical data from human and mouse brain, many of their tools limit the amount of genes and brain structures researchers can view at once. To complement their work, ABADV generates multiple pie charts, bar charts and heat maps of expression energy values for any given set of genes and brain structures. Such a suite of free and easy-to-understand visualizations allows for easy comparison of gene expression across multiple brain areas. In addition, each visualization links back to the ABA so researchers may view a summary of the experimental detail. ABADV is currently supported on modern web browsers and is compatible with expression energy data from the Allen Mouse Brain Atlas in situ hybridization data. By creating this web application, researchers can immediately obtain and survey numerous amounts of expression energy data from the ABA, which they can then use to supplement their work or perform meta-analysis. In the future, we hope to enable ABADV across multiple data resources.

  10. Spacecraft surface charging within geosynchronous orbit observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Sarno-Smith, Lois K.; Larsen, Brian A.; Skoug, Ruth M.; Liemohn, Michael W.; Breneman, Aaron; Wygant, John R.; Thomsen, Michelle F.

    2016-02-01

    Using the Helium Oxygen Proton Electron (HOPE) and Electric Field and Waves (EFW) instruments from the Van Allen Probes, we explored the relationship between electron energy fluxes in the eV and keV ranges and spacecraft surface charging. We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT. An algorithm to extract the H+ charging line in the HOPE instrument data was developed to better explore intense charging events. Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV. It is demonstrated that it is imperative to use both EFW potential measurements and the HOPE instrument ion charging line for examining times of extreme spacecraft charging of the Van Allen Probes. The results of this study show that elevated electron energy fluxes and high-electron pressures are present during times of spacecraft charging but these same conditions may also occur during noncharging times. We also show noneclipse significant negative charging events on the Van Allen Probes.

  11. Fossil evidence for Cretaceous escalation in angiosperm leaf vein evolution.

    PubMed

    Feild, Taylor S; Brodribb, Timothy J; Iglesias, Ari; Chatelet, David S; Baresch, Andres; Upchurch, Garland R; Gomez, Bernard; Mohr, Barbara A R; Coiffard, Clement; Kvacek, Jiri; Jaramillo, Carlos

    2011-05-17

    The flowering plants that dominate modern vegetation possess leaf gas exchange potentials that far exceed those of all other living or extinct plants. The great divide in maximal ability to exchange CO(2) for water between leaves of nonangiosperms and angiosperms forms the mechanistic foundation for speculation about how angiosperms drove sweeping ecological and biogeochemical change during the Cretaceous. However, there is no empirical evidence that angiosperms evolved highly photosynthetically active leaves during the Cretaceous. Using vein density (D(V)) measurements of fossil angiosperm leaves, we show that the leaf hydraulic capacities of angiosperms escalated several-fold during the Cretaceous. During the first 30 million years of angiosperm leaf evolution, angiosperm leaves exhibited uniformly low vein D(V) that overlapped the D(V) range of dominant Early Cretaceous ferns and gymnosperms. Fossil angiosperm vein densities reveal a subsequent biphasic increase in D(V). During the first mid-Cretaceous surge, angiosperm D(V) first surpassed the upper bound of D(V) limits for nonangiosperms. However, the upper limits of D(V) typical of modern megathermal rainforest trees first appear during a second wave of increased D(V) during the Cretaceous-Tertiary transition. Thus, our findings provide fossil evidence for the hypothesis that significant ecosystem change brought about by angiosperms lagged behind the Early Cretaceous taxonomic diversification of angiosperms.

  12. Fossil evidence for Cretaceous escalation in angiosperm leaf vein evolution

    PubMed Central

    Feild, Taylor S.; Brodribb, Timothy J.; Iglesias, Ari; Chatelet, David S.; Baresch, Andres; Upchurch, Garland R.; Gomez, Bernard; Mohr, Barbara A. R.; Coiffard, Clement; Kvacek, Jiri; Jaramillo, Carlos

    2011-01-01

    The flowering plants that dominate modern vegetation possess leaf gas exchange potentials that far exceed those of all other living or extinct plants. The great divide in maximal ability to exchange CO2 for water between leaves of nonangiosperms and angiosperms forms the mechanistic foundation for speculation about how angiosperms drove sweeping ecological and biogeochemical change during the Cretaceous. However, there is no empirical evidence that angiosperms evolved highly photosynthetically active leaves during the Cretaceous. Using vein density (DV) measurements of fossil angiosperm leaves, we show that the leaf hydraulic capacities of angiosperms escalated several-fold during the Cretaceous. During the first 30 million years of angiosperm leaf evolution, angiosperm leaves exhibited uniformly low vein DV that overlapped the DV range of dominant Early Cretaceous ferns and gymnosperms. Fossil angiosperm vein densities reveal a subsequent biphasic increase in DV. During the first mid-Cretaceous surge, angiosperm DV first surpassed the upper bound of DV limits for nonangiosperms. However, the upper limits of DV typical of modern megathermal rainforest trees first appear during a second wave of increased DV during the Cretaceous-Tertiary transition. Thus, our findings provide fossil evidence for the hypothesis that significant ecosystem change brought about by angiosperms lagged behind the Early Cretaceous taxonomic diversification of angiosperms. PMID:21536892

  13. The potential of paleozoic nonmarine trace fossils for paleoecological interpretations

    USGS Publications Warehouse

    Maples, C.G.; Archer, A.W.

    1989-01-01

    Many Late Paleozoic environments have been interpreted as marine because of the co-occurrence of supposedly exclusively marine trace fossils. Beginning in the Late Ordovician, however, nonmarine trace-fossil diversity increased throughout the Paleozoic. This diversification of nonmarine organisms and nonmarine trace fossils was especially prevalent in Devonian and later times. Diversification of freshwater organisms is indicated by the large number of freshwater fish, arthropods, annelids and molluscs that had developed by the Carboniferous. In addition to diverse freshwater assemblages, entirely terrestrial vertebrate and invertebrate ecosystems had developed by the Devonian. This rapid diversification of freshwater and terrestrial organisms is inherently linked to development and diversification of land plants and subsequent shedding of large quantities of organic detritus in nonmarine and marginal-marine areas. Nearshore marine organisms and their larvae that are able to tolerate relatively short periods of lowered salinities will follow salt-water wedges inland during times of reduced freshwater discharge. Similarly, amphidromous marine organisms will migrate periodically inland into nonmarine environments. Undoubtedly, both of these processes were active in the Paleozoic. However, both processes are restricted to stream/distributary channels, interdistributary bays, or estuaries. Therefore, the presence of diverse trace-fossil assemblages in association with floodplain deposits is interpreted to reflect true nonmarine adaptation and diversity. Conversely, diverse trace-fossil assemblages in association with stream/distributary channel deposits, interdistributary-bay deposits, or estuarine deposits may reflect migration of salt-water wedges inland, or migration of marine organisms into freshwater environments (amphidromy), or both. ?? 1989.

  14. Fossilization Processes in Thermal Springs

    NASA Technical Reports Server (NTRS)

    Farmer, Jack D.; Cady, Sherry; Desmarais, David J.; Chang, Sherwood (Technical Monitor)

    1995-01-01

    To create a comparative framework for the study of ancient examples, we have been carrying out parallel studies of the microbial biosedimentology, taphonomy and geochemistry of modem and sub-Recent thermal spring deposits. One goal of the research is the development of integrated litho- and taphofacies models for siliceous and travertline sinters. Thermal springs are regarded as important environments for the origin and early evolution of life on Earth, and we seek to utilize information from the fossil record to reconstruct the evolution of high temperature ecosystems. Microbial contributions to the fabric of thermal spring sinters occur when population growth rates keep pace with, or exceed rates of inorganic precipitation, allowing for the development of continuous biofilms or mats. In siliceous thermal springs, microorganisms are typically entombed while viable. Modes of preservation reflect the balance between rates of organic matter degradation, silica precipitation and secondary infilling. Subaerial sinters are initially quite porous and permeable and at temperatures higher than about 20 C, organic materials are usually degraded prior to secondary infilling of sinter frameworks. Thus, organically-preserved microfossils are rare and fossil information consists of characteristic biofabrics formed by the encrustation and underplating of microbial mat surfaces. This probably accounts for the typically low total organic carbon values observed in thermal spring deposits. In mid-temperature, (approx. 35 - 59 C) ponds and outflows, the surface morphology of tufted Phormidium mats is preserved through mat underplating by thin siliceous: crusts. Microbial taxes lead to clumping of ceils and/or preferred filament orientations that together define higher order composite fabrics in thermal spring stromatolites (e.g. network, coniform, and palisade). At lower temperatures (less than 35 C), Calothrix mats cover shallow terracette pools forming flat carpets or pustular

  15. [A study on Horace N. Allen's medicine and recognition of Korean body].

    PubMed

    Lee, Young Ah

    2011-12-31

    Je Jung Won was the first modern-style Government hospital built by the Korean King Ko-Jong in April 1885, and it was the medical missionary Horace Newton Allen(1858~1932) who made one of the greatest contributions to the establishment of the hospital. Allen was an American missionary. He graduated from Ohio Wesleyan University with a degree in theology in 1881, and completed one-yearcourse at Miami Medical College. In Korea and America he worked as a physician, a missionary, an American diplomatic minister to Korea and a Korean minister's secretary to America. While acting as a mediator between Korea and America, he knew and recorded the domestic and foreign situation of Korea during Gaehwagi(the civilized and enlightened age). Thus to study him is to understand Korea's Gaehwagi as well as to research American medical missionaries. During his stay in Korea(1884~1905), Allen steadily wrote diaries and letters about Korean politics, diplomacy, society, culture, and medicine. Thus his public/private record through diaries and letters(the quantity of these materials amounts to several thousands) supplements the Korean early modern era's historical record. However, until now these materials have received little scholarly attention from researchers except for a few historians of missionary work between Korea and America, or of Korean modern medicine. I intended to use these materials to suggest a new perspective on the study of Korean Gaehwagi. Allen, along with John W. Heron, who came to Seoul on June 21st 1885, treated about 10,460 Korean patients in the first year of the opening of JeJungWon. They made "the first annual report of the Korean Government Hospital". This report explained how Allen and Heron regarded and treated Korean patients. Allen's diaries, letters and other writings offer a realistic view of how the western people actually recognized the Korean people at that time. As a western doctor, Allen had an ambivalent attitude toward Korean medical concepts

  16. Fossil diatoms and neogene paleolimnology

    USGS Publications Warehouse

    Platt, Bradbury J.

    1988-01-01

    Diatoms have played an important role in the development of Neogene continental biostratigraphy and paleolimnology since the mid-19th Century. The history of progress in Quaternary diatom biostratigraphy has developed as a result of improved coring techniques that enable sampling sediments beneath existing lakes coupled with improved chronological control (including radiometric dating and varve enumeration), improved statistical treatment of fossil diatom assemblages (from qualitative description to influx calculations of diatom numbers or volumes), and improved ecological information about analogous living diatom associations. The last factor, diatom ecology, is the most critical in many ways, but progresses slowly. Fortunately, statistical comparison of modern diatom assemblages and insightful studies of the nutrient requirements of some common freshwater species are enabling diatom paleolimnologists to make more detailed interpretations of the Quaternary record than had been possible earlier, and progress in the field of diatom biology and ecology will continue to refine paleolimnological studies. The greater age and geologic setting of Tertiary diatomaceous deposits has prompted their study in the contexts of geologic history, biochronology and evolution. The distribution of diatoms of marine affinities in continental deposits has given geologists insights about tectonism and sea-level change, and the distribution of distinctive (extinct?) diatoms has found utilization both in making stratigraphic correlations between outcrops of diatomaceous deposits and in various types of biochronological studies that involve dating deposits in different areas. A continental diatom biochronologic scheme will rely upon evolution, such as the appearance of new genera within a family, in combination with regional environmental changes that are responsible for the wide distribution of distinctive diatom species. The increased use of the scanning electron microscope for the

  17. Design of advanced fossil-fuel systems (DAFFS): a study of three developing technologies for coal-fired, base-load electric power generation. Integrated coal-gasification/combined power plant with BGC/Lurgi gasification process

    SciTech Connect

    Not Available

    1983-06-01

    The objectives of this report are to present the facility description, plant layouts and additional information which define the conceptual engineering design, and performance and cost estimates for the BGC/Lurgi Integrated Gasification Combined Cycle (IGCC) power plant. Following the introductory comments, the results of the British Gas Corporation (BGC)/Lurgi IGCC power plant study are summarized in Section 2. In Secion 3, a description of plant systems and facilities is provided. Section 4 includes pertinent performance information and assessments of availability, natural resource requirements and environmental impact. Estimates of capital costs, operating and maintenance costs and cost of electricity are presented in Section 5. A Bechtel Group Inc. (BGI) assessment and comments on the designs provided by Burns and Roe-Humphreys and Glasgow Synthetic Fuels, Inc. (BRHG) are included in Section 6. The design and cost estimate reports which were prepared by BRHG for those items within their scope of responsibility are included as Appendices A and B, respectively. Apendix C is an equipment list for items within the BGI scope. The design and cost estimate classifications chart referenced in Section 5 is included as Appendix D. 8 references, 18 figures, 5 tables.

  18. Double fossilization in eukaryotic microorganisms from Lower Cretaceous amber

    PubMed Central

    Martín-González, Ana; Wierzchos, Jacek; Gutiérrez, Juan-Carlos; Alonso, Jesús; Ascaso, Carmen

    2009-01-01

    Background Microfossils are not only useful for elucidating biological macro- and microevolution but also the biogeochemical history of our planet. Pyritization is the most important and extensive mode of preservation of animals and especially of plants. Entrapping in amber, a fossilized resin, is considered an alternative mode of biological preservation. For the first time, the internal organization of 114-million-year-old microfossils entrapped in Lower Cretaceous amber is described and analyzed, using adapted scanning electron microscopy in backscattered electron mode in association with energy dispersive X-ray spectroscopy microanalysis. Double fossilization of several protists included in diverse taxonomical groups and some vegetal debris is described and analyzed. Results In protists without an exoskeleton or shell (ciliates, naked amoebae, flagellates), determinate structures, including the nuclei, surface envelopes (cortex or cytoplasmic membrane) and hyaloplasm are the main sites of pyritization. In protists with a biomineralized skeleton (diatoms), silicon was replaced by pyrite. Permineralization was the main mode of pyritization. Framboidal, subhedral and microcrystalline are the predominant pyrite textures detected in the cells. Abundant pyritized vegetal debris have also been found inside the amber nuggets and the surrounding sediments. This vegetal debris usually contained numerous pyrite framboids and very densely packed polycrystalline pyrite formations infilled with different elements of the secondary xylem. Conclusion Embedding in amber and pyritization are not always alternative modes of biological preservation during geological times, but double fossilization is possible under certain environmental conditions. Pyritization in protists shows a quite different pattern with regard to plants, due to the different composition and cellular architecture in these microorganisms and organisms. Anaerobic sulphate-reducing bacteria could play a crucial

  19. The original colours of fossil beetles.

    PubMed

    McNamara, Maria E; Briggs, Derek E G; Orr, Patrick J; Noh, Heeso; Cao, Hui

    2012-03-22

    Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group.

  20. Forty Years Later: Updating the Fossilization Hypothesis

    ERIC Educational Resources Information Center

    Han, ZhaoHong

    2013-01-01

    A founding concept in second language acquisition (SLA) research, fossilization has been fundamental to understanding second language (L2) development. The Fossilization Hypothesis, introduced in Selinker's seminal text (1972), has thus been one of the most influential theories, guiding a significant bulk of SLA research for four decades; 2012…

  1. Do alternative energy sources displace fossil fuels?

    NASA Astrophysics Data System (ADS)

    York, Richard

    2012-06-01

    A fundamental, generally implicit, assumption of the Intergovernmental Panel on Climate Change reports and many energy analysts is that each unit of energy supplied by non-fossil-fuel sources takes the place of a unit of energy supplied by fossil-fuel sources. However, owing to the complexity of economic systems and human behaviour, it is often the case that changes aimed at reducing one type of resource consumption, either through improvements in efficiency of use or by developing substitutes, do not lead to the intended outcome when net effects are considered. Here, I show that the average pattern across most nations of the world over the past fifty years is one where each unit of total national energy use from non-fossil-fuel sources displaced less than one-quarter of a unit of fossil-fuel energy use and, focusing specifically on electricity, each unit of electricity generated by non-fossil-fuel sources displaced less than one-tenth of a unit of fossil-fuel-generated electricity. These results challenge conventional thinking in that they indicate that suppressing the use of fossil fuel will require changes other than simply technical ones such as expanding non-fossil-fuel energy production.

  2. Precambrian biota: protistan origin of trace fossils?

    PubMed

    Pawlowski, Jan; Gooday, Andrew J

    2009-01-13

    Some Precambrian trace fossils have been presented as evidence for the early origin of bilaterians; the recent finding that large amoeboid protists leave macroscopic traces at the bottom of the deep ocean questions the metazoan nature of early trace fossils, stressing the importance of single-cell organisms in Precambrian biota.

  3. Atomic force microscopy of Precambrian microscopic fossils.

    PubMed

    Kempe, André; Schopf, J William; Altermann, Wladyslaw; Kudryavtsev, Anatoliy B; Heckl, Wolfgang M

    2002-07-09

    Atomic force microscopy (AFM) is a technique used routinely in material science to image substances at a submicron (including nm) scale. We apply this technique to analysis of the fine structure of organic-walled Precambrian fossils, microscopic sphaeromorph acritarchs (cysts of planktonic unicellular protists) permineralized in approximately 650-million-year-old cherts of the Chichkan Formation of southern Kazakhstan. AFM images, backed by laser-Raman spectroscopic analysis of individual specimens, demonstrate that the walls of these petrified fossils are composed of stacked arrays of approximately 200-nm-sized angular platelets of polycyclic aromatic kerogen. Together, AFM and laser-Raman spectroscopy provide means by which to elucidate the submicron-scale structure of individual microscopic fossils, investigate the geochemical maturation of ancient organic matter, and, potentially, distinguish true fossils from pseudofossils and probe the mechanisms of fossil preservation by silica permineralization.

  4. Atomic force microscopy of Precambrian microscopic fossils

    PubMed Central

    Kempe, André; Schopf, J. William; Altermann, Wladyslaw; Kudryavtsev, Anatoliy B.; Heckl, Wolfgang M.

    2002-01-01

    Atomic force microscopy (AFM) is a technique used routinely in material science to image substances at a submicron (including nm) scale. We apply this technique to analysis of the fine structure of organic-walled Precambrian fossils, microscopic sphaeromorph acritarchs (cysts of planktonic unicellular protists) permineralized in ≈650-million-year-old cherts of the Chichkan Formation of southern Kazakhstan. AFM images, backed by laser-Raman spectroscopic analysis of individual specimens, demonstrate that the walls of these petrified fossils are composed of stacked arrays of ≈200-nm-sized angular platelets of polycyclic aromatic kerogen. Together, AFM and laser-Raman spectroscopy provide means by which to elucidate the submicron-scale structure of individual microscopic fossils, investigate the geochemical maturation of ancient organic matter, and, potentially, distinguish true fossils from pseudofossils and probe the mechanisms of fossil preservation by silica permineralization. PMID:12089337

  5. Radio properties of fossil galaxy groups

    NASA Astrophysics Data System (ADS)

    Miraghaei, H.; Khosroshahi, H. G.

    2016-09-01

    We study 1.4 GHz radio properties of a sample of fossil galaxy groups using GMRT radio observations and the FIRST survey catalog. Fossil galaxy groups, having no recent major mergers in their dominant galaxies and also group scale mergers, give us the opportunity to investigate the effect of galaxy merger on AGN activity. In this work, we compare the radio properties of a rich sample of fossil groups with a sample of normal galaxy groups and clusters and show that the brightest group galaxies in fossil groups are under luminous at 1.4 GHz, relative to the general population of the brightest group galaxies, indicating that the dynamically relaxed nature of fossil groups has influenced the AGN activity in their dominant galaxy.

  6. Selective flotation of fossil resin from Western coal. Final report, July 1, 1990--May 25, 1992

    SciTech Connect

    Jensen, G.F.; Miller, J.D.

    1992-05-25

    The proof-of-concept test program was designed to clarify a number of concerns that have been raised by coal companies who own the valuable resin resource. First, from laboratory bench-scale flotation experiments, a froth product from cleaner flotation containing more than 80% hexane-extractable resin at higher than 80% recovery can be produced. Pilot-plant testing was initiated to demonstrate the selective flotation of fossil resin and to establish a better confidence level in the new technology. Second, pilot-plant testing was designed to evaluate the effect and impact of random variation in slurry solids concentration and feed grade on this new selective fossil resin flotation technology. The flotation performance obtained under these industrial conditions is more realistic for process evaluation. Third, more accurate operating cost data was to be obtained for economic analysis. Fourth, sufficient quantities of the fossil resin concentrate were to be produced from the test program for evaluation by potential industrial users. Fifth, and finally, optimum levels for the operating variables were to be established. Such information was required for eventual scale-up and design of a fossil resin flotation plant. The pilot-plant proof-of-concept testing of selective resinate flotation has demonstrated that: (1) technically, the new flotation technologies discovered at the University of Utah and then improved upon by Advanced Processing Technologies, Inc. provide a highly efficient means to selectively recover fossil resin from coal. The proof-of-concept continuous flotation circuit (about 0.1 tph) resulted in fossil resin recovery with the same separation efficiency as was obtained from laboratory bench-scale testing (more than 80% recovery at about 80% concentrate grade); and (2) economically, the selective flotation process has been shown to be sufficiently profitable to justify the development of a fossil resin industry based on this new flotation process.

  7. Spectroscopic studies of the fish fossils (Cladocyclus gardneri and Vinctifer comptoni) from the Ipubi Formation of the Cretaceous Period.

    PubMed

    Sousa Filho, F E; da Silva, J H; Saraiva, G D; Abagaro, B T O; Barros, O A; Saraiva, A A F; Viana, B C; Freire, P T C

    2016-03-15

    Fossils are mineralized remains or traces from animals, plants and other organisms aged to about 10(8)years. The chemical processes of fossilization are dated back from old geological periods on Earth. The understanding of these processes and the structure of the fossils are one of the goals of paleontology and geology in the sedimentary environments. Many researches have tried to unveil details about special kinds of biological samples; however, a lack of data is noticed for various other specimens. This study reports the investigations through infrared spectroscopy, X-ray fluorescence and X-ray diffraction measurements for two types of fish fossils from the Cretaceous Period. The sample of Cladocyclus gardneri and Vinctifer comptoni fossils were collected from the Ipubi Formation, being one of the less studied, among the formations that constitute the important Santana group in the Araripe Basin, Brazil. The results obtained through different techniques, showed that the C. gardneri fish fossil contains hydroxyapatite and calcite as constituents whereas its rock matrix was formed by calcite, quartz and pyrite. Regarding the V. comptoni, the measurements confirmed the presence of hydroxyapatite in the fossil and its rock matrix gypsum, pyrite, quartz and calcite. The above scientific data contributed to the understanding the fossil formation in the Ipubi Formation, an important environment of the Cretaceous Period, which is rich in well-preserved fossils from different species.

  8. Spectroscopic studies of the fish fossils (Cladocyclus gardneri and Vinctifer comptoni) from the Ipubi Formation of the Cretaceous Period

    NASA Astrophysics Data System (ADS)

    Sousa Filho, F. E.; da Silva, J. H.; Saraiva, G. D.; Abagaro, B. T. O.; Barros, O. A.; Saraiva, A. A. F.; Viana, B. C.; Freire, P. T. C.

    2016-03-01

    Fossils are mineralized remains or traces from animals, plants and other organisms aged to about 108 years. The chemical processes of fossilization are dated back from old geological periods on Earth. The understanding of these processes and the structure of the fossils are one of the goals of paleontology and geology in the sedimentary environments. Many researches have tried to unveil details about special kinds of biological samples; however, a lack of data is noticed for various other specimens. This study reports the investigations through infrared spectroscopy, X-ray fluorescence and X-ray diffraction measurements for two types of fish fossils from the Cretaceous Period. The sample of Cladocyclus gardneri and Vinctifer comptoni fossils were collected from the Ipubi Formation, being one of the less studied, among the formations that constitute the important Santana group in the Araripe Basin, Brazil. The results obtained through different techniques, showed that the C. gardneri fish fossil contains hydroxyapatite and calcite as constituents whereas its rock matrix was formed by calcite, quartz and pyrite. Regarding the V. comptoni, the measurements confirmed the presence of hydroxyapatite in the fossil and its rock matrix gypsum, pyrite, quartz and calcite. The above scientific data contributed to the understanding the fossil formation in the Ipubi Formation, an important environment of the Cretaceous Period, which is rich in well-preserved fossils from different species.

  9. Exploring the Relationship of Organizational Culture and Implicit Leadership Theory to Performance Differences in the Nuclear and Fossil Energy Industry

    NASA Astrophysics Data System (ADS)

    Cravey, Kristopher J.

    Notable performance differences exist between nuclear and fossil power generation plants in areas such as safety, outage duration efficiency, and capacity factor. This study explored the relationship of organizational culture and implicit leadership theory to these performance differences. A mixed methods approach consisting of quantitative instruments, namely the Organizational Culture Assessment Instrument and the GLOBE Leadership Scales, and qualitative interviews were used in this study. Subjects were operations middle managers in a U.S. energy company that serves nuclear or fossil power plants. Results from the quantitative instruments revealed no differences between nuclear and fossil groups in regards to organizational culture types and implicit leadership theories. However, the qualitative results did reveal divergence between the two groups in regards to what is valued in the organization and how that drives behaviors and decision making. These organizational phenomenological differences seem to explain why performance differences exist between nuclear and fossil plants because, ultimately, they affect how the organization functions.

  10. Selective Preservation of Fossil Ghost Fish

    NASA Astrophysics Data System (ADS)

    Meacham, Amanda

    2016-04-01

    A unique type of fossil fish preservation has been discovered in the Angelo Member (Fossil Lake) of the Green River Formation. The Angelo Member is a predominately evaporative deposit dominated by dolomite, but contains facies of fossiliferous laminated calcimicrite. Fossil fish occurring in two beds conspicuously lack bones. Fish in the lower bed are only preserved as organic material, including skin, pigments, and eyes. Fish in the upper bed have three-dimensional etching where bones once existed but also contain skin, pigments, and eyes. The top third of the upper bed often contains calcite crystals that are pseudomorphs after trona and possibly halite. Preliminary mineralogical analysis and mapping of evaporate facies suggests that this unique preservation may be related to lake geochemical conditions, such as high pH and alkalinity. To our knowledge, this is the first time this type of preservation has been observed and studied. Fossils and sediments within these beds are being studied both vertically and laterally through the one-meter thick sequence containing the fossil fish using XRD, isotopic, SEM, thin section, and total organic carbon analysis. Nine quarries, 0.5-1 meter square, were excavated for both fossils and rock samples along with 17 additional rock sample locations across an approximately 25-kilometer square region. This investigation has the capability of reconstructing the paleoenvironment and lake chemistry of Fossil Lake during the deposition of the "ghost-fish" beds and solving the mystery of the "missing bones" and the unusual process of preservation.

  11. Effect of the orbital debris environment on the high-energy Van Allen proton belt

    NASA Technical Reports Server (NTRS)

    Konradi, Andrei

    1988-01-01

    The lifetimes of high-energy (greater than 55 MeV) protons in the Van Allen radiation belt are calculated, assuming that in time the protons will collide with and be absorbed by particulate orbiting material. The calculations are based on the NASA/DoD Civil Needs Database for orbital debris (Gaines, 1966) and moderate assumptions of future space traffic. It is found that the lifetimes of high-energy protons below 1500 km will decrease, leading to a noticeable redution in their fluxes.

  12. Cognition About the Creative Process – Interview With Dr Andrew P. Allen

    PubMed Central

    Allen, Andrew P.; Loughnane, Lynda

    2016-01-01

    What is the relationship between the creative process and cognition and perception? Lynda Loughnane, a master’s student in Art and Process in Crawford College of Art and Design, Cork, Ireland interviewed Dr Andrew P. Allen about the subject. Areas covered include mindfulness, Type 1 and Type 2 thinking, stage theories of creativity, engagement with the art process and the artwork, phenomenology and consciousness with and without self report. The interview was constructed to cover a wide range of subject matter, so as to gather as much information as possible in layman's language about the cognitive process in relation to creativity and interaction with art. PMID:27872674

  13. Evaluation of Single Board Computers for the Antenna Controller at the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Harp, Gerald R.

    2002-12-01

    We review a variety off-the-shelf single board computers being considered for application in the Allen Telescope Array (ATA) for antenna control. The evaluation process used the following procedure: we developed an equivalent small program on each computer. This program communicates over a local area network (Ethernet) to a remote host, and makes some simple tests of the network bandwidth. The controllers are evaluated according to 1) the measured performance and 2) the time it takes to develop the software. Based on these tests we rate each controller and choose one based on the Ajile aJ-100 processor for application at the ATA.

  14. Science Highlights from the RBSP-ECT Particle Instrument Suite on NASA's Van Allen Probes Mission

    NASA Astrophysics Data System (ADS)

    Spence, Harlan

    2014-05-01

    The NASA Van Allen Probes mission includes an instrument suite known as the Radiation Belt Storm Probes (RBSP) - Energetic Particle, Composition, and Thermal Plasma (ECT) suite. RBSP-ECT contains a well-proven complement of particle instruments to ensure the highest quality measurements ever made in the radiation belts and the inner magnetosphere. The coordinated RBSP-ECT particle measurements, analyzed in combination with fields and waves observations and state of-the-art theory and modeling, provide new understanding on the acceleration, global distribution, and variability of radiation belt electrons and ions, key science objectives of NASA's Living With a Star program and the Van Allen Probes mission. The RBSP-ECT suite consists of three highly-coordinated instruments: the Helium Oxygen Proton Electron (HOPE) spectrometer, the Magnetic Electron Ion Spectrometer (MagEIS), and the Relativistic Electron Proton Telescope (REPT). Collectively these three instrument types cover comprehensively the full electron and ion spectra from one eV to 10's of MeV with sufficient energy resolution, pitch angle coverage and resolution, and with composition measurements in the critical energy range up to 50 keV and also from a few to 50 MeV/nucleon. All three instruments are based on measurement techniques proven in the radiation belts, then optimized to provide unambiguous separation of ions and electrons and clean energy responses even in the presence of extreme penetrating background environments. In this presentation, we summarize overall ECT science goals and then show scientific results derived from the ECT suite on the dual Van Allen Probes spacecraft to date. Mission operations began only in late October 2012, and we have now achieved significant results. Results presented here will include substantial progress toward resolving primary Van Allen Probes science targets, such as: the relative role of localized acceleration versus transport-generated particle acceleration

  15. Bayesian phylogenetic estimation of fossil ages

    PubMed Central

    Drummond, Alexei J.; Stadler, Tanja

    2016-01-01

    Recent advances have allowed for both morphological fossil evidence and molecular sequences to be integrated into a single combined inference of divergence dates under the rule of Bayesian probability. In particular, the fossilized birth–death tree prior and the Lewis-Mk model of discrete morphological evolution allow for the estimation of both divergence times and phylogenetic relationships between fossil and extant taxa. We exploit this statistical framework to investigate the internal consistency of these models by producing phylogenetic estimates of the age of each fossil in turn, within two rich and well-characterized datasets of fossil and extant species (penguins and canids). We find that the estimation accuracy of fossil ages is generally high with credible intervals seldom excluding the true age and median relative error in the two datasets of 5.7% and 13.2%, respectively. The median relative standard error (RSD) was 9.2% and 7.2%, respectively, suggesting good precision, although with some outliers. In fact, in the two datasets we analyse, the phylogenetic estimate of fossil age is on average less than 2 Myr from the mid-point age of the geological strata from which it was excavated. The high level of internal consistency found in our analyses suggests that the Bayesian statistical model employed is an adequate fit for both the geological and morphological data, and provides evidence from real data that the framework used can accurately model the evolution of discrete morphological traits coded from fossil and extant taxa. We anticipate that this approach will have diverse applications beyond divergence time dating, including dating fossils that are temporally unconstrained, testing of the ‘morphological clock', and for uncovering potential model misspecification and/or data errors when controversial phylogenetic hypotheses are obtained based on combined divergence dating analyses. This article is part of the themed issue ‘Dating species divergences

  16. Old World fossil record of modern-type hummingbirds.

    PubMed

    Mayr, Gerald

    2004-05-07

    I report on tiny skeletons of stem-group hummingbirds from the early Oligocene of Germany that are of essentially modern appearance and exhibit morphological specializations toward nectarivory and hovering flight. These are the oldest fossils of modern-type hummingbirds, which had not previously been reported from the Old World. The findings demonstrate that early hummingbird evolution was not restricted to the New World. They further suggest that bird-flower coevolution dates back to the early Oligocene and open another view on the origin of ornithophily in Old World plants.

  17. Spitzer Digs Up Galactic Fossil

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1

    [figure removed for brevity, see original site] Figure 2

    This false-color image taken by NASA's Spitzer Space Telescope shows a globular cluster previously hidden in the dusty plane of our Milky Way galaxy. Globular clusters are compact bundles of old stars that date back to the birth of our galaxy, 13 or so billion years ago. Astronomers use these galactic 'fossils' as tools for studying the age and formation of the Milky Way.

    Most clusters orbit around the center of the galaxy well above its dust-enshrouded disc, or plane, while making brief, repeated passes through the plane that each last about a million years. Spitzer, with infrared eyes that can see into the dusty galactic plane, first spotted the newfound cluster during its current pass. A visible-light image (inset of Figure 1) shows only a dark patch of sky.

    The red streak behind the core of the cluster is a dust cloud, which may indicate the cluster's interaction with the Milky Way. Alternatively, this cloud may lie coincidentally along Spitzer's line of sight.

    Follow-up observations with the University of Wyoming Infrared Observatory helped set the distance of the new cluster at about 9,000 light-years from Earth - closer than most clusters - and set the mass at the equivalent of 300,000 Suns. The cluster's apparent size, as viewed from Earth, is comparable to a grain of rice held at arm's length. It is located in the constellation Aquila.

    Astronomers believe that this cluster may be one of the last in our galaxy to be uncovered.

    This image composite was taken on April 21, 2004, by Spitzer's infrared array camera. It is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

    Galactic Fossil Found Behind Curtain of Dust In Figure 2, the image mosaic shows the same patch of sky in various wavelengths of light. While the

  18. A Fossil Group in Formation

    NASA Astrophysics Data System (ADS)

    Miller, Eric D.; Rappaport, Saul A.; McDonald, Michael; Bautz, Mark W.; Grant, Catherine E.; Veilleux, Sylvain

    2016-04-01

    In the current picture of hierarchical structure formation, galaxy groups play a vital role as the seeds from which large assemblies of matter form. Compact groups are also important environments in which to watch the fueling of star formation and AGN activity, as the conditions are ideal for galaxy-galaxy interactions. We have identified a galaxy system that may represent an intermediate or transition stage in group evolution. Shakhbazyan 1 (or SHK 1) is a remarkably compact collection of about ten massive, red-sequence galaxies within a region 100 kpc across. Several of these galaxies show signs of AGN activity, and new, deep optical observations with the Discovery Channel Telescope reveal an extended stellar envelope surrounding the galaxies. This envelope is much more extended than what would be expected from a superposition of normal galaxy envelopes, and it indicates a large amount of intra-group starlight, evidence that the galaxies in SHK 1 are dynamically interacting.We here present new Chandra spectral imaging observations of this unusual system that confirm the presence of an X-ray-emitting diffuse intra-group medium (IGM), with a temperature of 1.5 keV and X-ray luminosity of 1043 erg/s. Assuming hydrostatic equilibrium, the system is about 1/3 as massive as expected from the optical richness. In addition, three of the ten central galaxies exhibit signatures of X-ray AGN. The under-luminous IGM, high density of bright galaxies, and evidence for galaxy-galaxy interaction indicate that this system may be in a transition stage of galaxy merging, similar to that expected in the formation of a fossil group. Alternatively, SHK 1 may consist of multiple poor groups in the final stages of merging along our line of sight. We explore these scenarios and outline paths of future study for this enigmatic system.

  19. Plant maintenance and plant life extension issue, 2007

    SciTech Connect

    Agnihotri, Newal

    2007-03-15

    The focus of the March-April issue is on plant maintenance and plant life extension. Major articles/reports in this issue include: Three proposed COLs expected in 2007, by Dale E. Klein, U.S. Nuclear Regulatory Commission; Delivering behaviors that our customers value, by Jack Allen, Westinghouse Electric Company; Facilitating high-level and fuel waste disposal technologies, by Malcolm Gray, IAEA, Austria; Plant life management and long-term operation, by Pal Kovacs, OECD-NEA, France; Measuring control rod position, by R. Taymanov, K. Sapozhnikova, I. Druzhinin, D.I. Mendeleyev, Institue for Metrology, Russia; and, 'Modernization' means higher safety, by Svetlana Genova, Kozluduy NPP plc, Bulgaria.

  20. Fossil Finds Expand Early Hominid Anatomy.

    ERIC Educational Resources Information Center

    Bower, B.

    1991-01-01

    Hominid fossils found in late 1990 in Ethiopia are reported. A controversy surrounding these remains and those of earlier expeditions, including Lucy, over whether more than one species of hominid are represented is discussed. (CW)

  1. Evolution: Fossil Ears and Underwater Sonar.

    PubMed

    Lambert, Olivier

    2016-08-22

    A key innovation in the history of whales was the evolution of a sonar system together with high-frequency hearing. Fossils of an archaic toothed whale's inner ear bones provide clues for a stepwise emergence of underwater echolocation ability.

  2. The fossil record of the sixth extinction.

    PubMed

    Plotnick, Roy E; Smith, Felisa A; Lyons, S Kathleen

    2016-05-01

    Comparing the magnitude of the current biodiversity crisis with those in the fossil record is difficult without an understanding of differential preservation. Integrating data from palaeontological databases with information on IUCN status, ecology and life history characteristics of contemporary mammals, we demonstrate that only a small and biased fraction of threatened species (< 9%) have a fossil record, compared with 20% of non-threatened species. We find strong taphonomic biases related to body size and geographic range. Modern species with a fossil record tend to be large and widespread and were described in the 19(th) century. The expected magnitude of the current extinction based only on species with a fossil record is about half of that of one based on all modern species; values for genera are similar. The record of ancient extinctions may be similarly biased, with many species having originated and gone extinct without leaving a tangible record.

  3. Development incentives for fossil fuel subsidy reform

    NASA Astrophysics Data System (ADS)

    Jakob, Michael; Chen, Claudine; Fuss, Sabine; Marxen, Annika; Edenhofer, Ottmar

    2015-08-01

    Reforming fossil fuel subsidies could free up enough funds to finance universal access to water, sanitation, and electricity in many countries, as well as helping to cut global greenhouse-gas emissions.

  4. Inner Magnetosphere keV Ion Drift Path Boundaries as Observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Strangeway, R. J.; Zhang, J.; Larsen, B.

    2014-12-01

    The drifts of keV ions in the inner magnetosphere are controlled by both electric field drifts and gradient and curvature (i.e., magnetic field) drifts, and further the magnetic field drifts oppose the corotation electric field drift in the dusk local time sector. Consequently, the ion drift paths can be quite complicated with the medium-energy ions drifting close to the Earth, but still being on open drift paths. In addition, structure in the energy-time spectrograms can be a consequence of either particle injection or particle loss. In order to distinguish between the two we will compare the energy-time spectrograms acquired with the Helium Oxygen Proton Electron (HOPE) mass spectrometer on board the Van Allen Probes with predictions of drift path boundaries. The simplest model assumes a uniform convection electric field and dipole model field, and we will use this a starting point for the comparison. The model can be modified to include shielding of the convection electric field, and rotation in local time of the zero-energy dusk-side stagnation point. As an additional check of the model we will compare the electric field used in the model with the electric field as measured by the Van Allen Probes, as well as the validity of using a dipole magnetic field through comparison with the measured magnetic field.

  5. Ion Spectral Structures Observed by the Van Allen Probes and Cluster

    NASA Astrophysics Data System (ADS)

    Ferradas, C.; Zhang, J.; Luo, H.; Kistler, L. M.; Spence, H. E.; Larsen, B.; Skoug, R. M.; Funsten, H. O.; Reeves, G. D.

    2014-12-01

    During the last decades several missions have recorded the presence of dynamic spectral features of energetic ions in the inner magnetosphere. Previous studies have revealed single "nose-like" structures occurring alone and simultaneous nose-like structures (up to three). In this study we also include signatures of new types of ion structure, namely "trunk-like" and "tusk-like" structures. All the ion structures are named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. They constitute the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. Multi-spacecraft analysis of these structures is important to understand their spatial distribution and temporal evolution. Mass spectrometers onboard Cluster (in a polar orbit) and the Van Allen Probes (in an equatorial orbit) measure energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet, where these ion structures are observed. We present a statistical study of the ion structures, using >1-year measurements from the two missions during the Van Allen Probes era. The results provide important details about the spatial distribution (dependence on geocentric distance and magnetic local time), spectral features of the structures (e.g., characteristic energy and differences among species), and geomagnetic and solar wind conditions under which these structures occur.

  6. An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts.

    PubMed

    Baker, D N; Jaynes, A N; Hoxie, V C; Thorne, R M; Foster, J C; Li, X; Fennell, J F; Wygant, J R; Kanekal, S G; Erickson, P J; Kurth, W; Li, W; Ma, Q; Schiller, Q; Blum, L; Malaspina, D M; Gerrard, A; Lanzerotti, L J

    2014-11-27

    Early observations indicated that the Earth's Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep 'slot' region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location. Recent observations have revealed unexpected radiation belt morphology, especially at ultrarelativistic kinetic energies (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth's intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave-particle pitch angle scattering deep inside the Earth's plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

  7. Collier Cobb and Allen D. Hole: Geologic mentors to early soil scientists

    NASA Astrophysics Data System (ADS)

    Brevik, Eric C.

    Many influential individuals involved in the early US soil survey program were trained as geologists rather than as agronomists or soil scientists. Several geology departments served as pipelines for students interested in a career in soil survey. This paper looks at the professional history of two early mentors of these geologists turned soil surveyors and some of the students they sent on to the US soil survey and other soil science careers. Collier Cobb sent over 10 students to the soil survey starting in 1900 when US soil survey was in its infancy, including individuals of note such as Hugh H. Bennett, George N. Coffey, Williamson E. Hearn, and Thomas D. Rice. Allen D. Hole worked on soil surveys for the state of Indiana and sent over a dozen students on to US soil survey careers between 1911 and 1937, including Mark Baldwin and James Thorp. Francis Hole and Ralph McCracken, other students of Allen Hole, also went on to have distinguished soil science careers. These mentors and students clearly show the close ties that existed between soil science and geology in the United States during the early 1900s.

  8. Collier Cobb and Allen D. Hole: Geologic Mentors to Early American Soil Scientists

    NASA Astrophysics Data System (ADS)

    Brevik, E. C.

    2012-04-01

    Many influential individuals involved in the early United States soil survey program were trained as geologists rather than as agronomists or soil scientists. Several geology departments served as pipelines for students interested in a career in soil survey. This presentation looks at the professional history of two early mentors of these geologists turned soil surveyors and some of the students they sent on to the U.S. soil survey and other soil science careers. Collier Cobb (University of North Carolina) sent over 10 students to the soil survey starting in 1900 when U.S. soil survey was in its infancy, including individuals of note such as Hugh H. Bennett, George N. Coffey, Williamson E. Hearn, and Thomas D. Rice. Allen D. Hole (Earlham College, Indiana) worked on soil surveys for the state of Indiana and sent over a dozen students on to U.S. soil survey careers between 1911 and 1937, including Mark Baldwin and James Thorp. Francis Hole and Ralph McCracken, other students of Allen Hole, also went on to have distinguished soil science careers. These mentors and students clearly show the close ties that existed between soil science and geology in the United States during the early 1900s.

  9. Automatic registration of imaging mass spectrometry data to the Allen Brain Atlas transcriptome

    NASA Astrophysics Data System (ADS)

    Abdelmoula, Walid M.; Carreira, Ricardo J.; Shyti, Reinald; Balluff, Benjamin; Tolner, Else; van den Maagdenberg, Arn M. J. M.; Lelieveldt, B. P. F.; McDonnell, Liam; Dijkstra, Jouke

    2014-03-01

    Imaging Mass Spectrometry (IMS) is an emerging molecular imaging technology that provides spatially resolved information on biomolecular structures; each image pixel effectively represents a molecular mass spectrum. By combining the histological images and IMS-images, neuroanatomical structures can be distinguished based on their biomolecular features as opposed to morphological features. The combination of IMS data with spatially resolved gene expression maps of the mouse brain, as provided by the Allen Mouse Brain atlas, would enable comparative studies of spatial metabolic and gene expression patterns in life-sciences research and biomarker discovery. As such, it would be highly desirable to spatially register IMS slices to the Allen Brain Atlas (ABA). In this paper, we propose a multi-step automatic registration pipeline to register ABA histology to IMS- images. Key novelty of the method is the selection of the best reference section from the ABA, based on pre-processed histology sections. First, we extracted a hippocampus-specific geometrical feature from the given experimental histological section to initially localize it among the ABA sections. Then, feature-based linear registration is applied to the initially localized section and its two neighbors in the ABA to select the most similar reference section. A non-rigid registration yields a one-to-one mapping of the experimental IMS slice to the ABA. The pipeline was applied on 6 coronal sections from two mouse brains, showing high anatomical correspondence, demonstrating the feasibility of complementing biomolecule distributions from individual mice with the genome-wide ABA transcriptome.

  10. Marine ecological-risk assessment pilot study for Allen Harbor, Narragansett Bay, Rhode Island. Professional paper

    SciTech Connect

    Johnston, R.K.; Munns, W.R.; Mueller, C.; Nelson, W.G.; Pesch, G.G.

    1992-01-01

    An ecological risk assessment framework was applied to characterize aquatic risks associated with hazardous waste disposal at Naval Construction Battalion Center (NCBC) Davisville, Rhode Island. An initial screening phase (I) assessed exposure and related that exposure to toxicological endpoints for bivalves, amphipods, sea urchins, and biomarker assays. Results showed little evidence of major contamination in sediments or tissues except for relatively high levels of polychlorinated biphenols (PBC), butyltins compounds (TBT), and fecal coliforms observed in Allen Harbor. Effects were detected in mussel physiology, sea urchin fertilization and development, biomarker responses, and soft shell clam histology. Possible sources of contamination and toxicity from the landfill leachate, surface runoff, and recreational boating were examined using a temporaland spatial sampling scheme. Chemical and toxicological information obtained implicated all three sources as affecting Allen Harbor water quality. Laboratory bioassays of landfill exposure media, employing a variety of marine species using acute and chronic endpoints, are being used to provide data for the development of an exposure-response model for risk to the marine environment. The model will define current risk and provide an interpretive framework for long-term monitoring.

  11. Coordinated Radio and High-Energy Observations of Cygnus X-3 with the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Williams, Peter K. G.; Bower, G. C.; Tomsick, J. A.; Allen Telescope Array Team

    2011-01-01

    The microquasar Cygnus X-3 is one of the few Galactic sources known to produce relativistic jets and can be one of the brightest radio sources in the Galaxy when flaring. In late 2009 it became the first such system to be seen in the gamma-ray regime with detections by both AGILE and Fermi. We have observed Cyg X-3 at 3 GHz every 5 days for the past six months with the Allen Telescope Array in conjunction with space-based X-ray (INTEGRAL, RXTE) and gamma-ray (Fermi) observations. We present results from both the long-term dataset and intensive observing sessions in which we obtain the radio lightcurve of Cyg X-3 on 10-minute timescales. We focus particularly on a May 2010 minor flare event for which we have coverage in all three bands.The first phase of the ATA was funded through generous grants from the Paul G. Allen Family Foundation. UC Berkeley, the SETI Institute, the National Science Foundation (Grant No. 0540599), Sun Microsystems, Xilinx, Nathan Myhrvold, Greg Papadopoulos, and other corporations and individual donors contributed additional funding.

  12. Void structure of O+ ions in the inner magnetosphere observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Nakayama, Y.; Ebihara, Y.; Ohtani, S.; Gkioulidou, M.; Takahashi, K.; Kistler, L. M.; Tanaka, T.

    2016-12-01

    The Van Allen Probes Helium Oxygen Proton Electron instrument observed a new type of enhancement of O+ ions in the inner magnetosphere during substorms. As the satellite moved outward in the premidnight sector, the flux of the O+ ions with energy 10 keV appeared first in the energy-time spectrograms. Then, the enhancement of the flux spread toward high and low energies. The enhanced flux of the O+ ions with the highest energy remained, whereas the flux of the ions with lower energy vanished near apogee, forming what we call the void structure. The structure cannot be found in the H+ spectrogram. We studied the generation mechanism of this structure by using numerical simulation. We traced the trajectories of O+ ions in the electric and magnetic fields from the global magnetohydrodynamics simulation and calculated the flux of O+ ions in the inner magnetosphere in accordance with the Liouville theorem. The simulated spectrograms are well consistent with the ones observed by Van Allen Probes. We suggest the following processes. (1) When magnetic reconnection starts, an intensive equatorward and tailward plasma flow appears in the plasma lobe. (2) The flow transports plasma from the lobe to the plasma sheet where the radius of curvature of the magnetic field line is small. (3) The intensive dawn-dusk electric field transports the O+ ions earthward and accelerates them nonadiabatically to an energy threshold; (4) the void structure appears at energies below the threshold.

  13. 'Trunk-like' ion structures observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Kistler, L. M.; Spence, H.; Wolf, R.; Reeves, G. D.; Skoug, R. M.; Funsten, H. O.; Larsen, B.; Niehof, J. T.; MacDonald, E.; Friedel, R. H.

    2013-12-01

    Dynamic ion spectral features in the inner magnetosphere are the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. In this study, we report 'trunk-like' ion structures observed in situ by the Van Allen Probes on 2 November 2012. The trunk structures are present in heavy ions but not in H+. For the particular event, ion energies in the He+ trunks, located at L = 3.7-2.6, MLT = 8.8-10.3, and MLAT = -2.0-0.03°, vary monotonically from 3.5 to 0.04 keV. It is suggested that the trunk phenomenon is due to a combination of 1) deeper ion injections from storm activity, 2) the longer charge exchange lifetimes of heavy ions than H+, 3) the separation of a narrow layer of ions around the Alfvén layer from other convecting ions, and 4) the trajectory of the Van Allen Probes (i.e., an orbital effect). Both observation analysis and numerical modeling are utilized in the study.

  14. Observations and Simulations of Whistler-mode Waves Detected by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Bengtson, M.; Rosborough, S.; Stein, R. L.; Streltsov, A. V.; Matheny, M. M.

    2015-12-01

    In March of 2014, Van Allen Probe A observed several packets of whistler-mode waves while passing through the apogee of an orbit on the dayside magnetosphere. These waves were localized in regions of strong density inhomogeneity. For one observed wave, the wave maximum occurred within the center of the channel formed by a density enhancement. The other two waves were observed on either side of strong density depletion. We first determine the wave characteristics using data from Van Allen Probe A. Then, we use the observations to specify parameters in an electron MHD simulation to model the propagation of whistler-mode waves inside density structures. These observations and simulations demonstrate how whistler-mode waves can become trapped inside density structures, a phenomenon known as ducting. The density ducts serve to guide the whistler-mode waves into the earth's radiation belt while minimizing damping effects. The purpose of this research is to understand the role of density ducts in guiding whistler-mode waves, which will have important applications for remediation of energetic particles from the radiation belt.

  15. Electric and magnetic radial diffusion coefficients using the Van Allen probes data

    NASA Astrophysics Data System (ADS)

    Ali, Ashar F.; Malaspina, David M.; Elkington, Scot R.; Jaynes, Allison N.; Chan, Anthony A.; Wygant, John; Kletzing, Craig A.

    2016-10-01

    ULF waves are a common occurrence in the inner magnetosphere and they contribute to particle motion, significantly, at times. We used the magnetic and the electric field data from the Electric and Magnetic Field Instrument Suite and Integrated Sciences (EMFISIS) and the Electric Field and Waves instruments (EFW) on board the Van Allen Probes to estimate the ULF wave power in the compressional component of the magnetic field and the azimuthal component of the electric field, respectively. Using L∗, Kp, and magnetic local time (MLT) as parameters, we conclude that the noon sector contains higher ULF Pc-5 wave power compared with the other MLT sectors. The dawn, dusk, and midnight sectors have no statistically significant difference between them. The drift-averaged power spectral densities are used to derive the magnetic and the electric component of the radial diffusion coefficient. Both components exhibit little to no energy dependence, resulting in simple analytic models for both components. More importantly, the electric component is larger than the magnetic component by one to two orders of magnitude for almost all L∗ and Kp; thus, the electric field perturbations are more effective in driving radial diffusion of charged particles in the inner magnetosphere. We also present a comparison of the Van Allen Probes radial diffusion coefficients, including the error estimates, with some of the previous published results. This allows us to gauge the large amount of uncertainty present in such estimates.

  16. Genetic diversity and structure in the Endangered Allen Cays Rock Iguana, Cyclura cychlura inornata

    PubMed Central

    Aplasca, Andrea C.; Iverson, John B.; Welch, Mark E.; Colosimo, Giuliano

    2016-01-01

    The Endangered Allen Cays Rock Iguana (Cyclura cychlura inornata) is endemic to the Allen Cays, a tiny cluster of islands in the Bahamas. Naturally occurring populations exist on only two cays (<4 ha each). However, populations of unknown origin were recently discovered on four additional cays. To investigate patterns of genetic variation among these populations, we analyzed nuclear and mitochondrial markers for 268 individuals. Analysis of three mitochondrial gene regions (2,328 bp) and data for eight nuclear microsatellite loci indicated low genetic diversity overall. Estimates of effective population sizes based on multilocus genotypes were also extremely low. Despite low diversity, significant population structuring and variation in genetic diversity measures were detected among cays. Genetic data confirm the source population for an experimentally translocated population while raising concerns regarding other, unauthorized, translocations. Reduced heterozygosity is consistent with a documented historical population decline due to overharvest. This study provides the first range-wide genetic analysis of this subspecies. We suggest strategies to maximize genetic diversity during ongoing recovery including additional translocations to establish assurance populations and additional protective measures for the two remaining natural populations. PMID:26989628

  17. Type II Isopentenyl Diphosphate Isomerase: Probing the Mechanism with Alkyne/Allene Diphosphate Substrate Analogues†

    PubMed Central

    Sharma, Nagendra K.; Pan, Jian-Jung; Poulter, C. Dale

    2010-01-01

    Isopentenyl diphosphate isomerase (IDI) catalyzes the interconversion of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), the basic five-carbon building blocks of isoprenoid molecules. Two structurally unrelated classes of IDI are known. Type I IPP isomerase (IDI-1) utilizes a divalent metal in a protonation-deprotonation reaction. In contrast, the type II enzyme (IDI-2) requires reduced flavin, raising the possibility that the reaction catalyzed by IDI-2 involves the net addition/abstraction of a hydrogen atom. As part of our studies of the mechanism of isomerization for IDI-2, we synthesized allene and alkyne substrate analogues for the enzyme. These molecules are predicted to be substantially less reactive toward proton addition than IPP and DMAPP, but have similar reactivities toward hydrogen atom addition. This prediction was verified by calculations of gas phase heats of reaction for addition of a proton and of a hydrogen atom to 1-butyne (3) and 1,2-butadiene (4) to form the 1-buten-2-yl carbocation and radical, respectively, and related affinities for 2-methyl-1-butene (5) and 2-methyl-2-butene (6) using G3MP2B3 and CBS-QB3 protocols. Alkyne 1-OPP and allene 2-OPP were not substrates for Thermus thermophilus IDI-2 or Escherichia coli IDI-1, but instead were competitive inhibitors. The experimental and computational results are consistent with a protonation-deprotonation mechanism for the enzyme-catalyzed isomerization of IPP and DMAPP. PMID:20560533

  18. Impacts of intense inward and outward ULF wave radial diffusion on the Van Allen belts

    NASA Astrophysics Data System (ADS)

    Mann, Ian; Ozeke, Louis; Rae, I. Jonathan; Murphy, Kyle

    2016-07-01

    During geomagnetic storms, the power in ultra-low frequency (ULF) waves can be orders of magnitude larger than that predicted by statistics determined from an entire solar cycle. This is especially true during the main phase and early recovery phase. These periods of enhanced storm-time ULF wave power can have significant impacts on the morphology and structure of the Van Allen belts. Either fast inward or outward radial diffusion can result, depending on the profiles of the electron phase space density and the outer boundary condition at the edge of the belts. Small changes in the time sequence of powerful ULF waves, and the time sequence of any magnetopause shadowing or the recovery of plamasheet sources relative to the ULF wave occurrence, have a remarkable impact on the resulting structure of the belts. The overall impact of the enhanced ULF wave power is profound, but the response can be very different depending on the available source flux in the plasmasheet. We review these impacts by examining ultra-relativistic electron dynamics during seemingly different storms during the Van Allen Probe era, including during the Baker et al. third radiation belt, and show the observed behaviour can be largely explained by differences in the time sequence of events described above.

  19. Observations of Quasi-Periodic Whistler Mode Waves by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Hospodarsky, George; Wilkinson, Darrelle; Kurth, William; Kletzing, Craig; Santolik, Ondrej

    2016-10-01

    Observed in Earth's inner magnetosphere, quasi-periodic whistler mode emissions (QP) are electromagnetic waves in the frequency range from a few hundred Hz to a few kHz that exhibit a periodic modulation (typically a few minutes) of their wave intensity. These waves were first detected at high latitude ground stations, but more recently have been observed by a number of spacecraft, including the twin Van Allen Probes. The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrument simultaneously measures the vector wave magnetic field and electric field, allowing wave propagation parameters, such as wave normal angle and Poynting vector, to be obtained. Almost four years of Van Allen Probes data have been examined and a statistical survey of the occurrence and properties of the QP emissions has been performed. The QP emissions were found to have periods ranging from 1 to 16 minutes with events lasting from less than 1 hour up to 6 hours. Some events were detected on successive orbits and a number of events were simultaneously detected by both spacecraft, even during large spacecraft separations, providing an opportunity to investigate the source and propagation properties of these waves.

  20. Advanced Researech and Technology Development fossil energy materials program: Semiannual progress report for the period ending September 30, 1988

    SciTech Connect

    Not Available

    1989-01-01

    The objective of the ARandTD Fossil Energy Materials Program is to conduct research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. The ORNL Fossil Energy Materials Program Office compiles and issues this combined semiannual progress report from camera-ready copies submitted by each of the participating subcontractor organizations. This report of activities on the program is organized in accordance with a work breakdown structure in which projects are organized according to materials research thrust areas. These areas are (1) Structural Ceramics, (2) Alloy Development and Mechanical Properties, (3) Corrosion and Erosion of Alloys, and (4) Assessments and Technology Transfer. Individual projects are processed separately for the data bases.

  1. Identification of immunoreactive material in mammoth fossils.

    PubMed

    Schweitzer, Mary; Hill, Christopher L; Asara, John M; Lane, William S; Pincus, Seth H

    2002-12-01

    The fossil record represents a history of life on this planet. Attempts to obtain molecular information from this record by analysis of nucleic acids found within fossils of extreme age have been unsuccessful or called into question. However, previous studies have demonstrated the long-term persistence of peptides within fossils and have used antibodies to extant proteins to demonstrate antigenic material. In this study we address two questions: Do immunogenic/antigenic materials persist in fossils? and; Can fossil material be used to raise antibodies that will cross-react with extant proteins? We have used material extracted from a well-preserved 100000-300000-year-old mammoth skull to produce antisera. The specificity of the antisera was tested by ELISA, western blotting, and immunohistochemistry. It was demonstrated that antisera reacted specifically with the fossils and not the surrounding sediments. Reactivity of antisera with modern proteins and tissues was also demonstrated, as was the ability to detect evolutionary relationships via antibody-antigen interactions. Mass spectrometry demonstrated the presence of amino acids and specific peptides within the fossil. Peptides were purified by anion-exchange chromatography and sequenced by tandem mass spectrometry. The collagen-derived peptides may have been the source of at least some of the immunologic reactivity, but the antisera identified molecules that were not observed by mass spectrometry, indicating that immunologic methods may have greater sensitivity. Although the presence of peptides and amino acids was demonstrated, the exact nature of the antigenic material was not fully clarified. This report demonstrates that antibodies may be used to obtain information from the fossil record.

  2. Fossil fuels in the 21st century.

    PubMed

    Lincoln, Stephen F

    2005-12-01

    An overview of the importance of fossil fuels in supplying the energy requirements of the 21st century, their future supply, and the impact of their use on global climate is presented. Current and potential alternative energy sources are considered. It is concluded that even with substantial increases in energy derived from other sources, fossil fuels will remain a major energy source for much of the 21st century and the sequestration of CO2 will be an increasingly important requirement.

  3. From the IGY to the IHY: A Changing View of the Van Allen Radiation Belts

    NASA Astrophysics Data System (ADS)

    Hudson, M. K.

    2006-12-01

    Discovery of the Van Allen radiation belts by instrumentation flown on Explorer 1 in 1958 was the first major discovery of the Space Age. A view of the belts as static inner and outer zones of energetic particles with different sources, a double-doughnut encircling the Earth, became iconic to the point that their dynamic behavior and solar connection receded from public awareness and apparent scientific import. Then the Cycle 23 maximum in solar activity arrived in 1989-1991, the first approaching the activity level of the International Geophysical Year of 1957-58, when the Van Allen belts were first discovered. Delay in launch of the NASA-Air Force Combined Radiation Release and Effects Satellite, following the Challenger accident in 1986, led to having the right instruments in the right orbit at the right time to detect prompt injection of outer belt electrons and solar energetic protons into the `slot region' between the inner and outer belts, forming new trapped populations which lasted for years in an otherwise benign location. This event in March 1991, along with the great geomagnetic storm of March 1989, and our increased dependence on space technology since the early Explorer days, led to a resurgence of interest in the Van Allen radiation belts and understanding of their connectivity to the Sun. Additional instrumentation from NASA's International Solar Terrestrial Physics Program, the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) and IMAGE spacecraft from the Explorer program, NOAA and DOD spacecraft, and improved worldwide linkages of groundbased measurements have contributed much since 1991 to our understanding of the dynamic characteristics of the Van Allen belts. Further, the presence of continuous solar wind measurements beginning with the launch of WIND in 1994, and SOHO images of Coronal Mass Ejections and coronal hole sources of high speed solar wind flow have filled in the connection with solar activity qualitatively anticipated

  4. Cross-scale observations of the 2015 St. Patrick's day storm: THEMIS, Van Allen Probes, and TWINS

    NASA Astrophysics Data System (ADS)

    Goldstein, J.; Angelopoulos, V.; De Pascuale, S.; Funsten, H. O.; Kurth, W. S.; LLera, K.; McComas, D. J.; Perez, J. D.; Reeves, G. D.; Spence, H. E.; Thaller, S. A.; Valek, P. W.; Wygant, J. R.

    2017-01-01

    We present cross-scale magnetospheric observations of the 17 March 2015 (St. Patrick's Day) storm, by Time History of Events and Macroscale Interactions during Substorms (THEMIS), Van Allen Probes (Radiation Belt Storm Probes), and Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS), plus upstream ACE/Wind solar wind data. THEMIS crossed the bow shock or magnetopause 22 times and observed the magnetospheric compression that initiated the storm. Empirical models reproduce these boundary locations within 0.7 RE. Van Allen Probes crossed the plasmapause 13 times; test particle simulations reproduce these encounters within 0.5 RE. Before the storm, Van Allen Probes measured quiet double-nose proton spectra in the region of corotating cold plasma. About 15 min after a 0605 UT dayside southward turning, Van Allen Probes captured the onset of inner magnetospheric convection, as a density decrease at the moving corotation-convection boundary (CCB) and a steep increase in ring current (RC) proton flux. During the first several hours of the storm, Van Allen Probes measured highly dynamic ion signatures (numerous injections and multiple spectral peaks). Sustained convection after ˜1200 UT initiated a major buildup of the midnight-sector ring current (measured by RBSP A), with much weaker duskside fluxes (measured by RBSP B, THEMIS a and THEMIS d). A close conjunction of THEMIS d, RBSP A, and TWINS 1 at 1631 UT shows good three-way agreement in the shapes of two-peak spectra from the center of the partial RC. A midstorm injection, observed by Van Allen Probes and TWINS at 1740 UT, brought in fresh ions with lower average energies (leading to globally less energetic spectra in precipitating ions) but increased the total pressure. The cross-scale measurements of 17 March 2015 contain significant spatial, spectral, and temporal structure.

  5. Replacing baseload power plants with wind plants

    SciTech Connect

    Cavallo, A.J.

    1995-12-31

    Baseload nuclear power plants supply about 21 percent of the electricity consumed in the United States today, and as these plants are retired over the next 10 to 25 years, they will not be replicated. This will open a vast market for new generating facilities which should, if possible, be non-fossil fueled. Wind energy baseload systems are able to equal or exceed the technical performance of these nuclear plants at a delivered cost of energy of less than $0.05/kWh in wind class 4 regions. However, unless a new externality (the cost of maintaining the security of fossil fuel supply) is factored in to the extremely low market price of fossil fuels, wind and other renewable energy resources will not be able to compete with these fuels on the basis of simple economics over the next 20 to 30 years.

  6. Single nucleotide polymorphisms in the allene oxide synthase 2 gene are associated with field resistance to late blight in populations of tetraploid potato cultivars.

    PubMed

    Pajerowska-Mukhtar, Karolina; Stich, Benjamin; Achenbach, Ute; Ballvora, Agim; Lübeck, Jens; Strahwald, Josef; Tacke, Eckhard; Hofferbert, Hans-Reinhard; Ilarionova, Evgeniya; Bellin, Diana; Walkemeier, Birgit; Basekow, Rico; Kersten, Birgit; Gebhardt, Christiane

    2009-03-01

    The oomycete Phytophthora infestans causes late blight, the most relevant disease of potato (Solanum tuberosum) worldwide. Field resistance to late blight is a complex trait. When potatoes are cultivated under long day conditions in temperate climates, this resistance is correlated with late plant maturity, an undesirable characteristic. Identification of natural gene variation underlying late blight resistance not compromised by late maturity will facilitate the selection of resistant cultivars and give new insight in the mechanisms controlling quantitative pathogen resistance. We tested 24 candidate loci for association with field resistance to late blight and plant maturity in a population of 184 tetraploid potato individuals. The individuals were genotyped for 230 single nucleotide polymorphisms (SNPs) and 166 microsatellite alleles. For association analysis we used a mixed model, taking into account population structure, kinship, allele substitution and interaction effects of the marker alleles at a locus with four allele doses. Nine SNPs were associated with maturity corrected resistance (P < 0.001), which collectively explained 50% of the genetic variance of this trait. A major association was found at the StAOS2 locus encoding allene oxide synthase 2, a key enzyme in the biosynthesis of jasmonates, plant hormones that function in defense signaling. This finding supports StAOS2 as being one of the factors controlling natural variation of pathogen resistance.

  7. Single Nucleotide Polymorphisms in the Allene Oxide Synthase 2 Gene Are Associated With Field Resistance to Late Blight in Populations of Tetraploid Potato Cultivars

    PubMed Central

    Pajerowska-Mukhtar, Karolina; Stich, Benjamin; Achenbach, Ute; Ballvora, Agim; Lübeck, Jens; Strahwald, Josef; Tacke, Eckhard; Hofferbert, Hans-Reinhard; Ilarionova, Evgeniya; Bellin, Diana; Walkemeier, Birgit; Basekow, Rico; Kersten, Birgit; Gebhardt, Christiane

    2009-01-01

    The oomycete Phytophthora infestans causes late blight, the most relevant disease of potato (Solanum tuberosum) worldwide. Field resistance to late blight is a complex trait. When potatoes are cultivated under long day conditions in temperate climates, this resistance is correlated with late plant maturity, an undesirable characteristic. Identification of natural gene variation underlying late blight resistance not compromised by late maturity will facilitate the selection of resistant cultivars and give new insight in the mechanisms controlling quantitative pathogen resistance. We tested 24 candidate loci for association with field resistance to late blight and plant maturity in a population of 184 tetraploid potato individuals. The individuals were genotyped for 230 single nucleotide polymorphisms (SNPs) and 166 microsatellite alleles. For association analysis we used a mixed model, taking into account population structure, kinship, allele substitution and interaction effects of the marker alleles at a locus with four allele doses. Nine SNPs were associated with maturity corrected resistance (P < 0.001), which collectively explained 50% of the genetic variance of this trait. A major association was found at the StAOS2 locus encoding allene oxide synthase 2, a key enzyme in the biosynthesis of jasmonates, plant hormones that function in defense signaling. This finding supports StAOS2 as being one of the factors controlling natural variation of pathogen resistance. PMID:19139145

  8. On the generation of large amplitude spiky solitons by ultralow frequency earthquake emission in the Van Allen radiation belt

    SciTech Connect

    Mofiz, U. A.

    2006-08-15

    The parametric coupling between earthquake emitted circularly polarized electromagnetic radiation and ponderomotively driven ion-acoustic perturbations in the Van Allen radiation belt is considered. A cubic nonlinear Schroedinger equation for the modulated radiation envelope is derived, and then solved analytically. For ultralow frequency earthquake emissions large amplitude spiky supersonic bright solitons or subsonic dark solitons are found to be generated in the Van Allen radiation belt, detection of which can be a tool for the prediction of a massive earthquake may be followed later.

  9. Microgloma Sanders & Allen, 1973 (Nuculanidae) and Pristigloma Dall, 1900 (Pristiglomidae) (Pelecypoda) in the Campos Basin off Brazil

    PubMed Central

    Benaim, Natalia Pereira; Absalão, Ricardo Silva

    2011-01-01

    Abstract As a secondary result of oil prospecting in Brazil, samples from the Campos Basin continental slope became available. In these samples, specimens of the genera Microgloma Sanders & Allen, 1973 and Pristigloma Dall, 1900 were found. This contribution provides the southernmost record of the genus Microgloma, the first record of Microgloma mirmidina (Dautzenberg & Fischer 1897) from the western Atlantic, the descriptions of Microgloma macaron sp. n. and Microgloma nhanduti sp. n.as new species, and the shallowest record of Pristigloma alba Sanders & Allen 1973. PMID:22287903

  10. Fossil group origins - VI. Global X-ray scaling relations of fossil galaxy clusters

    NASA Astrophysics Data System (ADS)

    Kundert, A.; Gastaldello, F.; D'Onghia, E.; Girardi, M.; Aguerri, J. A. L.; Barrena, R.; Corsini, E. M.; De Grandi, S.; Jiménez-Bailón, E.; Lozada-Muñoz, M.; Méndez-Abreu, J.; Sánchez-Janssen, R.; Wilcots, E.; Zarattini, S.

    2015-11-01

    We present the first pointed X-ray observations of 10 candidate fossil galaxy groups and clusters. With these Suzaku observations, we determine global temperatures and bolometric X-ray luminosities of the intracluster medium (ICM) out to r500 for six systems in our sample. The remaining four systems show signs of significant contamination from non-ICM sources. For the six objects with successfully determined r500 properties, we measure global temperatures in the range 2.8 ≤ TX ≤ 5.3 keV, bolometric X-ray luminosities of 0.8 × 1044 ≤ LX, bol ≤ 7.7 × 1044 erg s-1, and estimate masses, as derived from TX, of M500 ≳ 1014 M⊙. Fossil cluster scaling relations are constructed for a sample that combines our Suzaku observed fossils with fossils in the literature. Using measurements of global X-ray luminosity, temperature, optical luminosity, and velocity dispersion, scaling relations for the fossil sample are then compared with a control sample of non-fossil systems. We find the fits of our fossil cluster scaling relations are consistent with the relations for normal groups and clusters, indicating fossil clusters have global ICM X-ray properties similar to those of comparable mass non-fossil systems.

  11. New baseload power plants

    SciTech Connect

    Not Available

    1993-04-01

    This is a tabulation of the results of this magazines survey of current plans for new baseload power plants. The table lists the unit name, capacity, fuel, engineering firm, constructor, suppliers for steam generator, turbine generator and flue gas desulfurization equipment, date due on-line, and any non-utility participants. The table includes fossil-fuel plants, nuclear plants, geothermal, biomass and hydroelectric plants.

  12. Refining of fossil resin flotation concentrate from western coal. First quarterly final report, February 23, 1993--March 31, 1993

    SciTech Connect

    Miller, J.D.

    1993-04-30

    During the first quarter of the project, from February 22, 1993 to March 31, 1993, the major work is to conduct project work plan and to organize the research term in order to successfully conduct this fossil resin refining project. Under a previous DOE-funded program, University of Utah and APT conducted a serious pilot-plant tests of selective flotation of fossil resin from Wasatch plateau coal (both UPL coal and CO-OP coal mines) of south central Utah. About 200 lbs high grade fossil resin flotation concentrate (approximate 75% resin content) was generated from those pilot-plant flotation tests. The resin flotation concentrate were naturally dried, sampled and storied into one kilo plastic bag for future use. The ash and moisture content of the resin concentrate is found to be 1.23% and 1.03 by weight respectively. As concluded from our previous research project, it was found that macroscopic fossil resin is friable and can be easily liberated from other coal macerals. Consequently the fossil resin particles tend to concentrate into the fine sizes during size reduction and coal preparation. Because of this property, the fine resinous coal streams in a coal preparation plant contain more than 6% hexane-soluble fossil resin, even when the run-of-mine coal contains only 3% fossil resin. Thus, the fossil resin flotation concentrate contains more fine resin particles ({minus}200 mesh). Under microscopic examination, it is also found that a notable amount of fine coal particle was still floated into the froth concentrate along with fossil resin particles.

  13. New Optimal Sensor Suite for Ultrahigh Temperature Fossil Fuel Applications

    SciTech Connect

    John Coggin; Jonas Ivasauskas; Russell G. May; Michael B. Miller; Rena Wilson

    2006-09-30

    Accomplishments during Phase II of a program to develop and demonstrate photonic sensor technology for the instrumentation of advanced powerplants are described. The goal of this project is the research and development of advanced, robust photonic sensors based on improved sapphire optical waveguides, and the identification and demonstration of applications of the new sensors in advanced fossil fuel power plants, where the new technology will contribute to improvements in process control and monitoring. During this program work period, major progress has been experienced in the development of the sensor hardware, and the planning of the system installation and operation. The major focus of the next work period will be the installation of sensors in the Hamilton, Ohio power plant, and demonstration of high-temperature strain gages during mechanical testing of SOFC components.

  14. Fossil Flora of the John Day Basin, Oregon

    USGS Publications Warehouse

    Knowlton, Frank Hall

    1902-01-01

    For a number of years I have been gradually accumulating material for a thorough revision of the Tertiary floras of the Pacific slope. Fossil plants are known to occur at numerous points within this area, and their study and identification has already furnished valuable data bearing on the geological history of the region, and when still further exploited it is confidently expected that they will afford more exact data for the use of geologists. This investigation is progressing satisfactorily, and at no distant day it is hoped to have it in form for final publication. From time to time various members of the United States Geological Survey, as well as others not connected with this organization, have sent in small collections of fossil plants for determination. These have been studied and reported upon as fully as the condition of the problem permitted, so that the determinations could be immediately available to geologists, but with the reservation that none of the questions could be fully settled until all known material had been studied and properly correlated. The rich fossil plant deposits in the John Day Basin, as set forth more fully in the historical account which follows, have been known for a period of nearly fifty years, but their study has been carried on in a more or less desultory manner. There has also been considerable confusion as to the horizons whence these plants came. As various species of plants described originally from the John Day region were detected in various other localities in Oregon, and in surrounding areas, as central Washington, western Idaho, and northern California, it became more than ever apparent that a thorough study of all material obtainable from this type area would be necessary before any definite or satisfactory conclusions could be reached. The immediate incentive for this revision was furnished by the receipt of a considerable collection of plants, made by Dr. John C. Merriam in 1900 while he was in charge of an

  15. Molecular fossils in Cretaceous condensate from western India

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sharmila; Dutta, Suryendu; Dutta, Ratul

    2014-06-01

    The present study reports the biomarker distribution of condensate belonging to the early Cretaceous time frame using gas chromatography-mass spectrometry (GC-MS). The early Cretaceous palaeoenvironment was inscribed into these molecular fossils which reflected the source and conditions of deposition of the condensate. The saturate fraction of the condensate is characterized by normal alkanes ranging from n-C9 to n-C29 (CPI-1.13), cycloalkanes and C14 and C15 sesquiterpanes. The aromatic fraction comprises of naphthalene, phenanthrene, their methylated derivatives and cyclohexylbenzenes. Isohexylalkylnaphthalenes, a product of rearrangement process of terpenoids, is detected in the condensate. Several aromatic sesquiterpenoids and diterpenoids have been recorded. Dihydro- ar-curcumene, cadalene and ionene form the assemblage of sesquiterpenoids which are indicative of higher plant input. Aromatic diterpenoid fraction comprises of simonellite and retene. These compounds are also indicative of higher plants, particularly conifer source which had been a predominant flora during the Cretaceous time.

  16. Advanced research and technology development fossil energy materials program. Quarterly progress report for the period ending September 30, 1981

    SciTech Connect

    Bradley, R.A.

    1981-12-01

    This is the fourth combined quarterly progress report for those projects that are part of the Advanced Research and Technology Development Fossil Energy Materials Program. The objective is to conduct a program of research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. Work performed on the program generally falls into the Applied Research and Exploratory Development categories as defined in the DOE Technology Base Review, although basic research and engineering development are also conducted. A substantial portion of the work on the AR and TD Fossil Energy Materials Program is performed by participating cntractor organizations. All subcontractor work is monitored by Program staff members at ORNL and Argonne National Laboratory. This report is organized in accordance with a work breakdown structure defined in the AR and TD Fossil Energy Materials Program Plan for FY 1981 in which projects are organized according to fossil energy technologies. We hope this series of AR and TD Fossil Energy Materials Program quarterly progress reports will aid in the dissemination of information developed on the program.

  17. A process concept for utilizing fossil fuel resources with reduced CO sub 2 emission

    SciTech Connect

    Steinberg, M.

    1989-04-01

    There is increasing evidence of the probability of a global carbon dioxide greenhouse warming effect. The concentration of CO{sub 2} in the atmosphere at the turn of the century was 280 ppM; presently it is 345 ppM, an increase of 23%. This increase has resulted mainly from human activity in burning increasing amounts of fossil fuel -- coal, oil, gas and from deforestation, the cutting down of forested areas. This paper discusses studies that have been made dealing with reducing CO{sub 2} emissions from coal burning power plants. Included are: CO{sub 2} can be removed, recovered and stored in the deep oceans; recover and utilize CO{sub 2} as a commodity; large acreages of trees can be planted to photosynthetically absorb the CO{sub 2} from fossil fuel plants; and improve energy technology efficiency of existing and future power plants. 5 refs., 1 fig., 3 tabs.

  18. Comparison of species-resolved energy spectra from ACE EPAM and Van Allen Probes RBSPICE

    NASA Astrophysics Data System (ADS)

    Patterson, J.; Manweiler, J. W.; Armstrong, T. P.; Lanzerotti, L. J.; Gerrard, A. J.; Gkioulidou, M.

    2013-12-01

    We present a comparison between energy spectra measured by the Advanced Composition Explorer (ACE) Electron Proton Alpha Monitor (EPAM) instrument and the Van Allen Probe Ion Composition Experiment (RBSPICE) for two significant and distinct events in early 2013. The first is an impulsive solar particle event on March 17th. While intense, this event presented no significant surprises in terms of its composition or anisotropy characteristics, thus providing a good baseline for response of the trapped radiation belts as observed by the Van Allen Probes. The second solar event occurred late May 22nd and early May 23rd. This event has a much greater concentration of medium and heavy ions than the St. Patrick's Day event, as well as having very peculiar energy spectra with evidence of two distinct populations. During the St. Patrick's Day Event, the energy spectra for helium, carbon, oxygen, neon, silicon, and iron all show the same spectral power law slope -3.1. The event shows strong anisotropy with intensities differing by a factor of four for both protons and Z>1 ions. The late May event also has strong anisotropy, and in the same directions as the St. Patrick's Day Event, but with very different composition and energy spectra. The spectra are much harder with power law spectral slopes of -0.5. Additionally, there is a significant spectral bump at 3 MeV/nuc for helium that is not present in the spectra of the heavier ions. The intensities of the heavier ions, however, show an increase that is an order of magnitude greater than the increase seen for helium. The March 17 RBSPICE observations show multiple injection events lasting for less than an hour each during the Van Allen Probes B apogees. These injections are seen in protons as well as Helium and only somewhat observed in Oxygen. Spectral slopes for the observations range from approximately -5 during quiet times to double peaked events with a spectral slope of approximately -2 at the beginning of the injection

  19. Fidelity of fossil n-alkanes from leaf to paleosol and applications to the Paleocene-Eocene Thermal Maximum

    NASA Astrophysics Data System (ADS)

    Bush, R. T.; McInerney, F. A.; Baczynski, A. A.; Wing, S. L.

    2011-12-01

    Long chain n-alkanes (C21-C35) are well-known as biomarkers of terrestrial plants. They can be preserved across a wide range of terrestrial and marine environments, survive in the sedimentary record for millions of years, and can serve as proxies for ancient environments. Most n-alkane records are derived from sediments rather than directly from fossil leaves. However, little is known about the fidelity of the n-alkane record: how and where leaf preservation relates to n-alkane preservation and how patterns of n-alkane carbon isotope ratios (δ13C) compare to living relatives. To examine these questions, we analyzed n-alkanes from fluvial sediments and individual leaf fossils collected in the Bighorn Basin, Wyoming, across the Paleocene-Eocene Thermal Maximum (PETM) carbon isotope excursion. We assessed the fidelity of the n-alkane signature from individual fossil leaves via three separate means. 1) Spatial variations were assessed by comparing n-alkane concentrations on a fossil leaf and in sediments both directly adjacent to the leaf and farther away. Absolute concentrations were greater within the compression fossil than in the directly adjacent sediment, which were in turn greater than in more distant sediment. 2) n-Alkane abundances and distributions were examined in fossil leaves having a range of preservational quality, from fossils with intact cuticle to carbonized fossils lacking cuticle and higher-order venation. The best preserved fossils preserved a higher concentration of n-alkanes and showed the most similar n-alkane distribution to living relatives. However, a strong odd over even predominance suggests a relatively unmodified plant source occurred in all samples regardless of preservation state. 3) n-Alkane δ13C values were measured for both fossil leaves and their living relatives. Both the saw-tooth pattern of δ13C values between odd and even chain lengths and the general decrease in δ13C values with increasing chain length are consistent with

  20. Fossil Energy Advanced Research and Technology Development (AR TD) Materials Program semiannual progress report for the period ending September 30, 1991

    SciTech Connect

    Judkins, R.R.; Cole, N.C.

    1992-04-01

    The objective of the Fossil Energy Advanced Research and Technology Development Materials Program is to conduct research and development on materials for fossil energy applications with a focus on the longer-term and generic needs of the various fossil fuel technologies. The Program includes research aimed toward a better understanding of materials behavior in fossil energy environments and the development of new materials capable of substantial enhancement of plant operations and reliability. Research is outlined in four areas: Ceramics, New Alloys, Corrosion and Erosion Research, and Technology Development and Transfer. (VC)

  1. Macroevolutionary developmental biology: Embryos, fossils, and phylogenies.

    PubMed

    Organ, Chris L; Cooper, Lisa Noelle; Hieronymus, Tobin L

    2015-10-01

    The field of evolutionary developmental biology is broadly focused on identifying the genetic and developmental mechanisms underlying morphological diversity. Connecting the genotype with the phenotype means that evo-devo research often considers a wide range of evidence, from genetics and morphology to fossils. In this commentary, we provide an overview and framework for integrating fossil ontogenetic data with developmental data using phylogenetic comparative methods to test macroevolutionary hypotheses. We survey the vertebrate fossil record of preserved embryos and discuss how phylogenetic comparative methods can integrate data from developmental genetics and paleontology. Fossil embryos provide limited, yet critical, developmental data from deep time. They help constrain when developmental innovations first appeared during the history of life and also reveal the order in which related morphologies evolved. Phylogenetic comparative methods provide a powerful statistical approach that allows evo-devo researchers to infer the presence of nonpreserved developmental traits in fossil species and to detect discordant evolutionary patterns and processes across levels of biological organization.

  2. Remarkable new results for high-energy protons and electrons in the inner Van Allen belt regions

    NASA Astrophysics Data System (ADS)

    Baker, Daniel N.

    2016-04-01

    Early observations indicated that the Earth's Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep 'slot' region largely devoid of particles between them. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location.. Recent Van Allen Probes observations have revealed an unexpected radiation belt morphology, especially at ultrarelativistic kinetic energies (more than several megaelectronvolts). The data show an exceedingly sharp inner boundary for the ultrarelativistic electrons right at L=2.8. Additional, concurrently measured data reveal that this barrier to inward electron radial transport is likely due to scattering by powerful human electromagnetic transmitter (VLF) wave fields. We show that weak, but persistent, wave-particle pitch angle scattering deep inside the Earth's plasmasphere due to manmade signals can act to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate. Inside of this distance, the Van Allen Probes data show that high energy (20 -100 MeV) protons have a double belt structure with a stable peak of flux at L~1.5 and a much more variable belt peaking at L~2.3.

  3. Choctaw Leadership in Oklahoma: The Allen Wright Family and Education in the Nineteenth and Early Twentieth Centuries

    ERIC Educational Resources Information Center

    Noley, Grayson; Smith, Joan K.; Vaughn, Courtney; Cesar, Dana

    2009-01-01

    Against the backdrop of internal colonialism, this article examines the educational and social lives of Allen Wright and his children to better understand how this Choctaw family successfully navigated the pressures of dual cultures by: (1) providing the socio-political context of the indigenous culture prior to Wright's birth; (2) chronicling and…

  4. Rearrangement of vinyl allene oxide geometric isomers to cyclopentenones. Further computational insights with biologically relevant model systems.

    PubMed

    González-Pérez, Adán B; Grechkin, Alexander; de Lera, Ángel R

    2017-03-28

    Pathways for the rearrangement of the E and Z isomers of allyl- and methyl-substituted vinyl allene oxides to stereodefined cyclopentenones have been studied by DFT computations. Regardless of the reactant geometry, cis-configured cyclopentenones are found to be formed in a stepwise cascade comprising as key steps the ring opening of the oxirane to give an oxidopentadienyl diradical, its isomerization, and electrocyclization. An allyl substituent at the Csp(3) atom of the starting vinyl allene oxide induces opposite effects on the activation energies for ring opening: a decrease owing to assistance by homoconjugation for the out motion and an increase due to the stereoelectronic stabilization of the reactant. As a result, allyl- and methyl-substituted vinyl allene oxides exhibit comparable activation energies. Only model systems with crotyl substituents afford lower activation energies than the methyl counterparts due to the additional stabilization of the forming charge deficiency at a secondary carbon by homoconjugation. Moreover, upon homoconjugative interaction reactants of Z geometry are predicted to undergo cyclization more readily than the E isomers. The results with Z-crotyl substituent are congruent with the spontaneous rearrangement of natural vinyl allene oxide derived from α-linolenic acid to a racemic cis-cyclopentenone (12-oxo-PDA).

  5. Frontiers in Laser Cooling, Single-Molecule Biophysics, and Enrgy Science: A Talk from Leo Holberg and Allen Mills

    ScienceCinema

    Holberg, Leo; Mills, Allen [NIST

    2016-07-12

    Leo Holberg and Allen Mills present a talk at Frontiers in Laser Cooling, Single-Molecule Biophysics and Energy Science, a scientific symposium honoring Steve Chu, director of Lawrence Berkeley National Laboratory and recipient of the 1997 Nobel Prize in Physics. The symposium was held August 30, 2008 in Berkeley.

  6. Rapid Asymmetric Synthesis of Disubstituted Allenes by Coupling of Flow‐Generated Diazo Compounds and Propargylated Amines

    PubMed Central

    Poh, Jian‐Siang; Makai, Szabolcs; von Keutz, Timo; Tran, Duc N.; Battilocchio, Claudio; Pasau, Patrick

    2017-01-01

    Abstract We report herein the asymmetric coupling of flow‐generated unstabilized diazo compounds and propargylated amine derivatives, using a new pyridinebis(imidazoline) ligand, a copper catalyst and base. The reaction proceeds rapidly, generating chiral allenes in 10–20 minutes with high enantioselectivity (89–98 % de/ee), moderate yields and a wide functional group tolerance. PMID:28075518

  7. A finite difference method for a conservative Allen-Cahn equation on non-flat surfaces

    NASA Astrophysics Data System (ADS)

    Kim, Junseok; Jeong, Darae; Yang, Seong-Deog; Choi, Yongho

    2017-04-01

    We present an efficient numerical scheme for the conservative Allen-Cahn (CAC) equation on various surfaces embedded in a narrow band domain in the three-dimensional space. We apply a quasi-Neumann boundary condition on the narrow band domain boundary using the closest point method. This boundary treatment allows us to use the standard Cartesian Laplacian operator instead of the Laplace-Beltrami operator. We apply a hybrid operator splitting method for solving the CAC equation. First, we use an explicit Euler method to solve the diffusion term. Second, we solve the nonlinear term by using a closed-form solution. Third, we apply a space-time-dependent Lagrange multiplier to conserve the total quantity. The overall scheme is explicit in time and does not need iterative steps; therefore, it is fast. A series of numerical experiments demonstrate the accuracy and efficiency of the proposed hybrid scheme.

  8. Long-duration exohiss waves outside the plasmasphere: observed by Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhu, H.; Su, Z.; Xiao, F.; Zheng, H.; Wang, Y.; He, Z.; Shen, C.; Zhang, M.; Wang, S.; Kletzing, C.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Reeves, G. D.; Funsten, H. O.; Blake, J. B.; Baker, D. N.

    2014-12-01

    We report an exohiss event in the low-density trough region observed by Van Allen Probes on 2 February 2014. These exohiss waves are discovered in the wide MLT distribution [9.1,13.4] and low magnetic latitude, with narrow-band structure and weak intensity compared with plasmaspheric hiss. Using the Continue Waveform Burst Mode data and MAG data on the EMFISIS, we analyze the normal angle, electromagnetic planarity and anti~/parallel-propagating Poynting flux of exohiss wave. The results show indicate that exohiss waves are the result of plasmaspheric hiss leakage into the trough region. The dependence of the proportion of anti~/parallel-propagating Poynting flux on MLT can be explained by Landau damping associated with suprathermal eletrons.

  9. Wave-driven butterfly distribution of Van Allen belt relativistic electrons

    SciTech Connect

    Xiao, Fuliang; Yang, Chang; Su, Zhenpeng; Zhou, Qinghua; He, Zhaoguo; He, Yihua; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.

    2015-10-05

    Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day–night asymmetry in Earth’s magnetic field. However, direct observation of a butterfly distribution well inside of geostationary orbit and the origin of this phenomenon have not been provided so far. Here we report high-resolution observation that a unusual butterfly pitch angle distribution of relativistic electrons occurred within 5 Earth radii during the 28 June 2013 geomagnetic storm. In conclusion, simulation results show that combined acceleration by chorus and magnetosonic waves can successfully explain the electron flux evolution both in the energy and butterfly pitch angle distribution. Finally, the current provides a great support for the mechanism of wave-driven butterfly distribution of relativistic electrons.

  10. George Herbert Mead and the Allen controversy at the University of Wisconsin.

    PubMed

    Cook, Gary A

    2007-01-01

    This essay uses previously unpublished correspondence of George Herbert Mead to tell the story of his involvement in the aftermath of a political dispute that took place at the University of Wisconsin during the years 1914-1915. It seeks thereby to clarify the historical significance of an article he published on this controversy in late 1915. Taken together with relevant information about the educational activities of William H. Allen of the New York Bureau of Municipal Research, Mead's correspondence and article throw helpful light upon his understanding of how an educational survey of a university should proceed; they also show how he went about the task of evaluating a failed attempt at such a survey.

  11. Statistical distribution of EMIC wave spectra: Observations from Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhang, X.-J.; Li, W.; Thorne, R. M.; Angelopoulos, V.; Bortnik, J.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.

    2016-12-01

    It has been known that electromagnetic ion cyclotron (EMIC) waves can precipitate ultrarelativistic electrons through cyclotron resonant scattering. However, the overall effectiveness of this mechanism has yet to be quantified, because it is difficult to obtain the global distribution of EMIC waves that usually exhibit limited spatial presence. We construct a statistical distribution of EMIC wave frequency spectra and their intensities based on Van Allen Probes measurements from September 2012 to December 2015. Our results show that as the ratio of plasma frequency over electron gyrofrequency increases, EMIC wave power becomes progressively dominated by the helium band. There is a pronounced dawn-dusk asymmetry in the wave amplitude and the frequency spectrum. The frequency spectrum does not follow the commonly used single-peak Gaussian function. Incorporating these realistic EMIC wave frequency spectra into radiation belt models is expected to improve the quantification of EMIC wave scattering effects in ultrarelativistic electron dynamics.

  12. Van Allen Probes observations of oxygen cyclotron harmonic waves in the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Usanova, M. E.; Malaspina, D. M.; Jaynes, A. N.; Bruder, R. J.; Mann, I. R.; Wygant, J. R.; Ergun, R. E.

    2016-09-01

    Waves with frequencies in the vicinity of the oxygen cyclotron frequency and its harmonics have been regularly observed on the Van Allen Probes satellites during geomagnetic storms. We focus on properties of these waves and present events from the main phase of two storms on 1 November 2012 and 17 March 2013 and associated dropouts of a few MeV electron fluxes. They are electromagnetic, in the frequency range ~0.5 to several Hz, and amplitude ~0.1 to a few nT in magnetic and ~0.1 to a few mV/m in electric field, with both the wave velocity and the Poynting vector directed almost parallel to the background magnetic field. These properties are very similar to those of electromagnetic ion cyclotron waves, which are believed to contribute to loss of ring current ions and radiation belt electrons and therefore can be also important for inner magnetosphere dynamics.

  13. Wave-driven butterfly distribution of Van Allen belt relativistic electrons.

    PubMed

    Xiao, Fuliang; Yang, Chang; Su, Zhenpeng; Zhou, Qinghua; He, Zhaoguo; He, Yihua; Baker, D N; Spence, H E; Funsten, H O; Blake, J B

    2015-10-05

    Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day-night asymmetry in Earth's magnetic field. However, direct observation of a butterfly distribution well inside of geostationary orbit and the origin of this phenomenon have not been provided so far. Here we report high-resolution observation that a unusual butterfly pitch angle distribution of relativistic electrons occurred within 5 Earth radii during the 28 June 2013 geomagnetic storm. Simulation results show that combined acceleration by chorus and magnetosonic waves can successfully explain the electron flux evolution both in the energy and butterfly pitch angle distribution. The current provides a great support for the mechanism of wave-driven butterfly distribution of relativistic electrons.

  14. Five Years of SETI with the Allen Telescope Array: Lessons Learned

    NASA Astrophysics Data System (ADS)

    Harp, Gerald

    2016-01-01

    We discuss recent observations at the Allen Telescope Array (ATA) supporting a wide ranging Search for Extraterrestrial Intelligence (SETI). The ATA supports observations over the frequency range 1-10 GHz with three simultaneous phased array beams used in an anticoincidence detector for false positive rejection. Here we summarize observational results over the years 2011-2015 covering multiple campaigns of exoplanet stars, the galactic plane, infrared excess targets, etc. Approximately 2 x 108 signals were identified and classified over more than 5000 hours of observation. From these results we consider various approaches to the rapid identification of human generated interference in the process of the search for a signal with origins outside the radius of the Moon's orbit. We conclude that the multi-beam technique is superb tool for answering the very difficult question of the direction of origin of signals. Data-based simulations of future instruments with more than 3 beams are compared.

  15. Convection Electric Field Observations by THEMIS and the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Califf, S.; Li, X.; Bonnell, J. W.; Wygant, J. R.; Malaspina, D.; Hartinger, M.; Thaller, S. A.

    2013-12-01

    We present direct electric field measurements made by THEMIS and the Van Allen Probes in the inner magnetosphere, focusing on the large-scale, near-DC convection electric field. The convection electric field drives plasma Earthward from the tail into the inner magnetosphere, playing a critical role in forming the ring current. Although it is normally shielded deep inside the magnetosphere, during storm times this large-scale electric field can penetrate to low L values (L < 3), eroding the plasmasphere and also providing a mechanism for ~100 keV electron injection into the slot region and inner radiation belt. The relationship of the convection electric field with the plasmasphere is also important for understanding the dynamic outer radiation belt, as the plasmapause boundary has been strongly correlated with the dynamic variation of the outer radiation belt electrons.

  16. Traveling wave solutions for bistable fractional Allen-Cahn equations with a pyramidal front

    NASA Astrophysics Data System (ADS)

    Chan, Hardy; Wei, Juncheng

    2017-05-01

    Using the method of sub-super-solution, we construct a solution of (- Δ) s u - cuz - f (u) = 0 on R3 of pyramidal shape. Here (- Δ) s is the fractional Laplacian of sub-critical order 1 / 2 < s < 1 and f is a bistable nonlinearity. Hence, the existence of a traveling wave solution for the parabolic fractional Allen-Cahn equation with pyramidal front is asserted. The maximum of planar traveling wave solutions in various directions gives a sub-solution. A super-solution is roughly defined as the one-dimensional profile composed with the signed distance to a rescaled mollified pyramid. In the main estimate we use an expansion of the fractional Laplacian in the Fermi coordinates.

  17. EMIC wave scale size in the inner magnetosphere: Observations from the dual Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Blum, L. W.; Bonnell, J. W.; Agapitov, O.; Paulson, K.; Kletzing, C.

    2017-02-01

    Estimating the spatial scales of electromagnetic ion cyclotron (EMIC) waves is critical for quantifying their overall scattering efficiency and effects on thermal plasma, ring current, and radiation belt particles. Using measurements from the dual Van Allen Probes in 2013-2014, we characterize the spatial and temporal extents of regions of EMIC wave activity and how these depend on local time and radial distance within the inner magnetosphere. Observations are categorized into three types—waves observed by only one spacecraft, waves measured by both spacecraft simultaneously, and waves observed by both spacecraft with some time lag. Analysis reveals that dayside (and H+ band) EMIC waves more frequently span larger spatial areas, while nightside (and He+ band) waves are more often localized but can persist many hours. These investigations give insight into the nature of EMIC wave generation and support more accurate quantification of their effects on the ring current and outer radiation belt.

  18. Wave-driven butterfly distribution of Van Allen belt relativistic electrons

    NASA Astrophysics Data System (ADS)

    Xiao, Fuliang; Yang, Chang; Su, Zhenpeng; Zhou, Qinghua; He, Zhaoguo; He, Yihua; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.

    2015-10-01

    Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day-night asymmetry in Earth's magnetic field. However, direct observation of a butterfly distribution well inside of geostationary orbit and the origin of this phenomenon have not been provided so far. Here we report high-resolution observation that a unusual butterfly pitch angle distribution of relativistic electrons occurred within 5 Earth radii during the 28 June 2013 geomagnetic storm. Simulation results show that combined acceleration by chorus and magnetosonic waves can successfully explain the electron flux evolution both in the energy and butterfly pitch angle distribution. The current provides a great support for the mechanism of wave-driven butterfly distribution of relativistic electrons.

  19. Wave-driven butterfly distribution of Van Allen belt relativistic electrons

    PubMed Central

    Xiao, Fuliang; Yang, Chang; Su, Zhenpeng; Zhou, Qinghua; He, Zhaoguo; He, Yihua; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.

    2015-01-01

    Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day–night asymmetry in Earth's magnetic field. However, direct observation of a butterfly distribution well inside of geostationary orbit and the origin of this phenomenon have not been provided so far. Here we report high-resolution observation that a unusual butterfly pitch angle distribution of relativistic electrons occurred within 5 Earth radii during the 28 June 2013 geomagnetic storm. Simulation results show that combined acceleration by chorus and magnetosonic waves can successfully explain the electron flux evolution both in the energy and butterfly pitch angle distribution. The current provides a great support for the mechanism of wave-driven butterfly distribution of relativistic electrons. PMID:26436770

  20. Van Allen Probe Explorations of Plasma Spatial and Temporal Scales in the Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Niehof, J. T.; Larsen, B.; Skoug, R. M.; Reeves, G. D.; MacDonald, E.; Thomsen, M.; Funsten, H. O.; Friedel, R. H.

    2013-12-01

    We utilize the variable separation of the twin satellites of the Van Allen Probes mission to explore the time and spatial stability of plasma features in the inner magnetosphere. The spacecraft are in a leader-follower configuration with an approximately nine hour orbit, but with slightly different apogees and thus periods. Exploiting the resulting variation in separations, we survey differences in the plasma environment between inbound and outbound passes from a single satellite and between the two separated in time. The time separation ranges from minutes to 4.5 hours. From the HOPE instrument we obtain pitch angle resolved measurements of the plasma environment (for electrons, protons, helium, and oxygen). By utilizing both spacecraft, temporal and spatial effects are separated. By comparing temporal variations to drift and flow times, we determine which events' evolution is adequately described by simple flow or drift and which must result from more involved physics.

  1. Explaining occurrences of auroral kilometric radiation in Van Allen radiation belts

    NASA Astrophysics Data System (ADS)

    Xiao, Fuliang; Zhou, Qinghua; Su, Zhenpeng; He, Zhaoguo; Yang, Chang; Liu, Si; He, Yihua; Gao, Zhonglei

    2016-12-01

    Auroral kilometric radiation (AKR) is a strong terrestrial radio emission and dominates at higher latitudes because of reflection in vicinities of the source cavity and plasmapause. Recently, Van Allen Probes have observed occurrences of AKR emission in the equatorial region of Earth's radiation belts but its origin still remains an open question. Equatorial AKR can produce efficient acceleration of radiation belt electrons and is a risk to space weather. Here we report high-resolution observations during two small storm periods 4-6 April and 18-20 May 2013 and show, using a 3-D ray tracing simulation, that AKR can propagate downward all the way into the equatorial plane in the radiation belts under appropriate conditions. The simulated results can successfully explain the observed AKR's spatial distribution and frequency range, and the current results have a wide application to all other magnetized astrophysical objects in the universe.

  2. Variation of the ion composition in the ring current during magnetic storms: Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Luo, Hao; Du, Aimin; Ge, Yasong; Cao, Xin; Zhang, Ying; Wang, Yuan

    2015-04-01

    It has been reported that the energy density of the oxygen ions in the ring current region will show more enhancements than protons during magnetic storms. Knowing how the ion composition changes during a magnetic storm is important for understanding the dynamic processes in the inner magnetosphere. By using ion flux data from HOPE and RBSPICE instruments on board the Van Allen probes, we study the energy density variation of both protons and oxygen ions during fifteen strong magnetic storms (minimum Dst < -80 nT) happened during year 2013 to 2014. Results provide important details about the ion composition at different storm stages and different magnetic local times. Results also give important indications about the ion acceleration in the inner magnetosphere and the source of the ring current ions during the magnetic storms.

  3. Van Allen Probes Empirical Model of the Plasma Environment Inside Geostationary Orbit

    NASA Astrophysics Data System (ADS)

    Larsen, B.; Reeves, G. D.; Friedel, R. H. W.; Thomsen, M. F.; Skoug, R. M.; Funsten, H. O.; MacDonald, E.

    2014-12-01

    With the Van Allen probes nearing a full precession around the Earth we present a parameterized empirical model of the plasma properties in the inner magnetosphere. Data from the Los Alamos National Laboratory built Helium-Oxygen-Proton-Electron (HOPE) spectrometer on this this unparalleled two-satellite mission provides excellent coverage of the equatorial magnetosphere inside of geostationary, albeit over a limited range of geomagnetic activity. Fusing data and derived products from the two spacecraft a specification of the state of the inner magnetosphere has been created providing species resolved fluxes, partial densities, temperatures, anisotropies, and ratios. This full coverage model reproduces some well know phenomenology and presents some lesser know behaviors providing new insights into details of plasma dynamics inside geostationary orbit.

  4. PIC Simulations of Banded Chorus Events from Van Allen Probes Observations

    NASA Astrophysics Data System (ADS)

    Fu, X.; Cowee, M.; Friedel, R. H.; Gary, S. P.; Hospodarsky, G. B.; Kletzing, C.; Liu, K.; MacDonald, E.; Reeves, G. D.; Skoug, R. M.; Winske, D.

    2013-12-01

    Banded chorus emissions are whistler waves with two bands separated by a narrow gap at 0.5ωce (ωce is the elctron gyro-frequency) in the frequency spectrum, often observed in the inner magnetosphere. The physical reason for the gap is still puzzling the space community. To better understand banded chorus generation, we identify occurrences of banded chorus in the Van Allen Probes EMFISIS data. Prameters derived from observations are used as initial conditions for our linear theory and nonlinear particle-in-cell simulations. By comparing our simulation results with electron pitch angle distributions from HOPE and wave spectra from EMFISIS, we will test some hypotheses for generation of banded chorus. LA-UR-13-26132.

  5. Solar thermal technologies as a bridge from fossil fuels to renewables

    NASA Astrophysics Data System (ADS)

    Dalvi, Vishwanath Haily; Panse, Sudhir V.; Joshi, Jyeshtharaj B.

    2015-11-01

    Integrating solar thermal systems into Rankine-cycle power plants can be done with minimal modification to the existing infrastructure. This presents an opportunity to introduce these technologies into the commercial space incrementally, to allow engineers to build familiarity with the systems before phasing out fossil-fuel energy with solar electricity. This paper shows that there is no thermodynamic barrier to injecting solar thermal heat into Rankine-cycle plants to offset even up to 50% fossil-fuel combustion with existing technology: with better solar-to-electricity efficiencies than conventionally deployed solar-thermal power plants. This strategy is economically preferable to installing carbon-capture and compression equipment for mitigating an equivalent amount of greenhouse-gas emissions. We suggest that such projects be encouraged by extending the same subsidy/incentives to the solar-thermal fraction of a `solar-aided’ plant that would be offered to a conventionally deployed solar-thermal power plant of similar capacity. Such a policy would prepare the ground for an incremental solar-thermal takeover of fossil-fuel power plants.

  6. Recent Performance Testing Results Using the 3-element Production Test Array for the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Tarter, J. C.; Blitz, L.; ATA 25 person Team; Paul G. Allen Foundation Collaboration

    2002-12-01

    The Allen Telescope Array will consist of 350 fixed six-meter dishes at the Hat Creek Radio Observatory in northern California (land use permits pending). It is the first massively parallel array ever built. Where possible, components from consumer markets and mass-production manufacturing processes have been used to lower costs. The architecture of the array explicitly anticipates future growth as a result of "Moore's Law" improvements. There will be many novel features of this array including ultra-wideband instantaneous frequency coverage from 0.5 to 11 GHz, a very wide field of view (2.5 degrees across at 21 cm), miniaturized 80K cryogenics, full bandwidth analog data transmission from the antennas to the Myhrvold central processing facility, dynamic null-formation and tracking of satellite interferers, and continuous multi-user support for radio astronomical research and SETI explorations. Starting in July 2000, the technology development for this array has been a collaboration between the Paul G. Allen Foundation and the ATA team located at the SETI Institute and at the Radio Astronomy Laboratory at UC Berkeley. A rapid prototyping array (RPA) consisting of seven COTS antennas and room temperature L-band receivers was erected in Orinda, CA in March 2001. Thanks to strong and continuing support from Sun Microsystems, the RPA has provided an invaluable testbed for software development and evaluation of RFI mitigation schemes. An operational 3-element Production Test Array (PTA) has been implemented at Hat Creek Observatory over the last few months. The antennas, drives, monitor and control software, and frontend components are near-final versions to be manufactured for the full array. This poster provides performance data from the first few months of testing with the PTA. A final decision on commitment for construction is expected by April 1, 2003.

  7. Formation of the oxygen torus in the inner magnetosphere: Van Allen Probes observations

    DOE PAGES

    Nose, Masahito; Oimatsu, S.; Keika, K.; ...

    2015-02-19

    Here we study the formation process of an oxygen torus during the 12–15 November 2012 magnetic storm, using the magnetic field and plasma wave data obtained by Van Allen Probes. We estimate the local plasma mass density (ρL) and the local electron number density (neL) from the resonant frequencies of standing Alfvén waves and the upper hybrid resonance band. The average ion mass (M) can be calculated by M ~ ρL/neL under the assumption of quasi-neutrality of plasma. During the storm recovery phase, both Probe A and Probe B observe the oxygen torus at L = 3.0–4.0 and L =more » 3.7–4.5, respectively, on the morning side. The oxygen torus has M = 4.5–8 amu and extends around the plasmapause that is identified at L~3.2–3.9. We find that during the initial phase, M is 4–7 amu throughout the plasma trough and remains at ~1 amu in the plasmasphere, implying that ionospheric O+ ions are supplied into the inner magnetosphere already in the initial phase of the magnetic storm. Numerical calculation under a decrease of the convection electric field reveals that some of thermal O+ ions distributed throughout the plasma trough are trapped within the expanded plasmasphere, whereas some of them drift around the plasmapause on the dawnside. This creates the oxygen torus spreading near the plasmapause, which is consistent with the Van Allen Probes observations. We conclude that the oxygen torus identified in this study favors the formation scenario of supplying O+ in the inner magnetosphere during the initial phase and subsequent drift during the recovery phase.« less

  8. Generation and effects of EMIC waves observed by the Van Allen Probes on 18 March 2013

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Saikin, A.; Gamayunov, K. V.; Spence, H. E.; Larsen, B.; Geoffrey, R.; Smith, C. W.; Torbert, R. B.; Kurth, W. S.; Kletzing, C.

    2015-12-01

    Electromagnetic ion cyclotron (EMIC) waves play a crucial role in particle dynamics in the Earth's magnetosphere. The free energy for EMIC wave generation is usually provided by the temperature anisotropy of the energetic ring current ions. EMIC waves can in turn cause particle energization and losses through resonant wave-particle interactions. Using measurements from the Van Allen Probes, we perform a case study of EMIC waves and associated plasma conditions observed on 18 March 2013. From 0204 to 0211 UT, the Van Allen Probe-B detected He+-band EMIC wave activity in the post-midnight sector (MLT=4.6-4.9) at very low L-shells (L=2.6-2.9). The event occurred right outside the inward-pushed plasmapause in the early recovery phase of an intense geomagnetic storm - min. Dst = -132 nT at 2100 UT on 17 March 2013. During this event, the fluxes of energetic (> 1 keV), anisotropic O+ dominate both the H+ and He+ fluxes in this energy range. Meanwhile, O+ fluxes at low energies (< 0.1 keV) are low compared to H+ and He+ fluxes in the same energy range. The fluxes of <0.1 keV He+ are clearly enhanced during the wave event, indicating a signature of wave heating. To further confirm the association of the observed plasma features with the EMIC waves, we calculate the electron minimum resonant energy (Emin) and pitch angle diffusion coefficient (Dαα) of the EMIC wave packets by using nominal ion composition, derived total ion density from the frequencies of upper hybrid resonance, and measured ambient and wave magnetic field. EMIC wave growth rates are also calculated to evaluate the role of loss-cone distributed ring current ions in the EMIC wave generation.

  9. Pi2 Pulsations Observed by Van Allen Probes: A Case Study

    NASA Astrophysics Data System (ADS)

    Ghamry, E.; Kim, K. H.; Kwon, H. J.; Lee, D. H.; Kletzing, C.; Kurth, W. S.

    2014-12-01

    The plasmaspheric virtual resonance model has been proposed as one of the source mechanisms for low-latitude Pi2 pulsations. Few studies have used simultaneous multipoint observations in space to examine the spatial structure of Pi2 pulsations both inside and outside the plasmasphere. In this study we show multipoint observations for Pi2 pulsations using the Van Allen Probes (RBSP-A and RBSP-B). We focus on the two events that occurred between 1700 and 2000 UT on March 12, 2013, which were simultaneously observed by Van Allen Probes and Bohyun (BOH, L = 1.35) station in South Korea. By using plasma density measurements, we determined that during this time RBSP-A was located outside the plasmasphere and RBSP-B was located inside it. We found that the poloidal, radial (δBx) and compressional (δBz), magnetic field components, and the azimuthal (Ey) electric field component observed by both RBSP-A and RBSP-B have a high correlation with the H component at BOH for both events. The δBx and δBz oscillations at both RBSP-A and RBSP-B are nearly out of phase with ground Pi2. The Ey -H cross phases at RBSP-A outside the plasmapause and RBSP-B inside the plasmapause are nearly in quadrature for the first Pi2 event. These observations indicate that the Pi2 pulsations exist outside the plasmasphere with a radially standing signature which supports the plasmaspheric virtual resonance model.

  10. Formation of the oxygen torus in the inner magnetosphere: Van Allen Probes observations

    SciTech Connect

    Nose, Masahito; Oimatsu, S.; Keika, K.; Kletzing, C. A.; Kurth, W. S.; De Pascuale, S.; Smith, C. W.; MacDowall, R. J.; Reeves, Geoffrey D.; Nakano, S.; Spence, H. E.; Larsen, Brian Arthur

    2015-02-19

    Here we study the formation process of an oxygen torus during the 12–15 November 2012 magnetic storm, using the magnetic field and plasma wave data obtained by Van Allen Probes. We estimate the local plasma mass density (ρL) and the local electron number density (neL) from the resonant frequencies of standing Alfvén waves and the upper hybrid resonance band. The average ion mass (M) can be calculated by M ~ ρL/neL under the assumption of quasi-neutrality of plasma. During the storm recovery phase, both Probe A and Probe B observe the oxygen torus at L = 3.0–4.0 and L = 3.7–4.5, respectively, on the morning side. The oxygen torus has M = 4.5–8 amu and extends around the plasmapause that is identified at L~3.2–3.9. We find that during the initial phase, M is 4–7 amu throughout the plasma trough and remains at ~1 amu in the plasmasphere, implying that ionospheric O+ ions are supplied into the inner magnetosphere already in the initial phase of the magnetic storm. Numerical calculation under a decrease of the convection electric field reveals that some of thermal O+ ions distributed throughout the plasma trough are trapped within the expanded plasmasphere, whereas some of them drift around the plasmapause on the dawnside. This creates the oxygen torus spreading near the plasmapause, which is consistent with the Van Allen Probes observations. We conclude that the oxygen torus identified in this study favors the formation scenario of supplying O+ in the inner magnetosphere during the initial phase and subsequent drift during the recovery phase.

  11. New results from the Colorado CubeSat and comparison with Van Allen Probes data

    NASA Astrophysics Data System (ADS)

    Li, X.

    2013-05-01

    The Colorado Student Space Weather Experiment (CSSWE) is a 3-unit (10cm x 10cm x 30cm) CubeSat mission funded by the NSF, launched into a highly inclined (650) low-Earth (490km x 790km) orbit on 09/13/12 as a secondary payload under NASA's Educational Launch of Nanosatellites (ELaNa) program. CSSWE contains a single science payload, the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), which is a simplified and miniaturized version of the Relativistic Electron and Proton Telescope (REPT) built at the Laboratory for Atmospheric and Space Physics (LASP) of University of Colorado for NASA/Van Allen Probes mission, which consists of two identical spacecraft, launched on 08/30/12, that traverse the heart of the radiation belts in a low inclination (100) orbit. REPTile is designed to measure the directional differential flux of protons ranging from 9 to 40 MeV and electrons from 0.5 to >3.3 MeV. Three-month science mission (full success) was completed on 1/05/13. We are now into the extended mission phase, focusing on data analysis and modeling. REPTile measures a fraction of the total population that has small enough equatorial pitch angles to reach the altitude of CSSWE, thus measuring the precipitating population as well as the trapped population. These measurements are critical for understanding the loss of outer radiation belt electrons. New results from CSSWE and comparison with Van Allen Probes data will be presented. The CSSWE is also an ideal class project, involving over 65 graduate and undergraduate students and providing training for the next generation of engineers and scientists over the full life-cycle of a satellite project.

  12. Analysis of Van Allen Probes Data Showing Nonlinear Electric Field Feedback During a Magnetic Storm

    NASA Astrophysics Data System (ADS)

    Liemohn, M. W.; Katus, R. M.; Smith, L. K.; Skoug, R. M.; Niehof, J. T.; Spence, H.; Wygant, J. R.; Bonnell, J. W.; Smith, C. W.; Kletzing, C.; Ilie, R.; Ganushkina, N.

    2013-12-01

    Van Allen Probes data was examined to assess the role of nonlinear feedback in relationship to the spatial structure of hot ions in the inner magnetosphere. During the magnetic storm that peaked on June 1, 2013, localized electric field perturbations from the EFW instrument were observed in relationship to the plasma pressure peak (as identified by the HOPE H+ and O+ fluxes in the 1-40 keV range, as well as magnetic field perturbations from EMFISIS) with a systematic sinusoidal perturbation. Near apogee, it takes the Van Allen Probes 30-60 minutes to traverse a peak in the ion fluxes. Therefore, the electric field was averaged over several minutes to remove the higher-frequency wave oscillations, revealing the longer-baseline perturbation associated with the pressure peak. While the fluxes indicate that the satellite is passing through a pressure peak, the magnetic field perturbation reveals the spatial location of the pressure extrema relative to the spacecraft location. The pattern of these electric fields relative to the location of the plasma pressure peak is in agreement with the hypothesis based on theory and numerical simulation results that an azimuthally localized pressure peak should create a systematic and predictable small-scale reconfiguration of the electric field. This electric field modification is because the field-aligned currents near each end of the pressure crescent close via Pedersen currents, perturbing the electric field in this region, as regulated by the ionospheric conductance. The level of this reconfiguration, relative to the expected dawn-dusk electric field within the magnetosphere, indicates the intensity of the nonlinear feedback.

  13. Ancient wet aeolian environments on Earth: Clues to presence of fossil/live microorganisms on Mars

    USGS Publications Warehouse

    Mahaney, W.C.; Milner, M.W.; Netoff, D.I.; Malloch, D.; Dohm, J.M.; Baker, V.R.; Miyamoto, H.; Hare, T.M.; Komatsu, G.

    2004-01-01

    Ancient wet aeolian (wet-sabkha) environments on Earth, represented in the Entrada and Navajo sandstones of Utah, contain pipe structures considered to be the product of gas/water release under pressure. The sediments originally had considerable porosity allowing the ingress of living plant structures, microorganisms, clay minerals, and fine-grained primary minerals of silt and sand size from the surface downward in the sedimentary column. Host rock material is of a similar size and porosity and presumably the downward migration of fine-grained material would have been possible prior to lithogenesis and final cementation. Recent field emission scanning electron microscopy (FESEM) and EDS (energy-dispersive spectrometry) examination of sands from fluidized pipes in the Early Jurassic Navajo Sandstone reveal the presence of fossil forms resembling fungal filaments, some bearing hyphopodium-like structures similar to those produced by modern tropical leaf parasites. The tropical origin of the fungi is consistent with the paleogeography of the sandstone, which was deposited in a tropical arid environment. These fossil fungi are silicized, with minor amounts of CaCO3 and Fe, and in some cases a Si/Al ratio similar to smectite. They exist as pseudomorphs, totally depleted in nitrogen, adhering to the surfaces of fine-grained sands, principally quartz and orthoclase. Similar wet aeolian paleoenvironments are suspected for Mars, especially following catastrophic sediment-charged floods of enormous magnitudes that are believed to have contributed to rapid formation of large water bodies in the northern plains, ranging from lakes to oceans. These events are suspected to have contributed to a high frequency of constructional landforms (also known as pseudocraters) related to trapped volatiles and water-enriched sediment underneath a thick blanket of materials that were subsequently released to the martian surface, forming piping structures at the near surface and

  14. High-Temperature Corrosion in Fossil Fuel Power Generation: Present and Future

    NASA Astrophysics Data System (ADS)

    Pint, B. A.

    2013-08-01

    Fossil fuels have historically represented two-thirds of all electricity generation in the United States and are projected to continue to play a similar role despite historically low projected growth rates in electricity demand and the recent dramatic shift from coal to more natural gas usage. Economic and environmental drivers will require more reliable and efficient fossil fuel generation systems in the future, likely with new system designs, higher operating temperatures, and more aggressive environments. Some of the current corrosion issues in power plants are reviewed along with research on materials solutions for systems envisioned for the near future, such as coal gasification and oxy-fired coal boilers.

  15. Paleobotany of Livingston Island: The first report of a Cretaceous fossil flora from Hannah Point

    USGS Publications Warehouse

    Leppe, M.; Michea, W.; Muñoz, C.; Palma-Heldt, S.; Fernandoy, F.

    2007-01-01

    This is the first report of a fossil flora from Hannah Point, Livingston Island, South Shetland Islands, Antarctica. The fossiliferous content of an outcrop, located between two igneous rock units of Cretaceous age are mainly composed of leaf imprints and some fossil trunks. The leaf assemblage consists of 18 taxa of Pteridophyta, Pinophyta and one angiosperm. The plant assemblage can be compared to other Early Cretaceous floras from the South Shetland Islands, but several taxa have an evidently Late Cretaceous affinity. A Coniacian-Santonian age is the most probable age for the outcrops, supported by previous K/Ar isotopic studies of the basalts over and underlying the fossiliferous sequence

  16. Selective flotation of fossil resin from western coal. Quarterly report, August 31, 1991--November 30, 1991

    SciTech Connect

    Jensen, G.F.; Miller, J.D.

    1992-03-30

    Economic analysis of this fossil resin project mainly focused on the flotation plant which is intended to be designed with data obtained from the current proof-of-concept flotation test program. It is believed that the analysis of this step is fairly accurate. The other two economic aspects of fossil in resin recovery/utilization are refining and marketing. Cost data used for refining were from an estimated base and are believed to have a large variance. Marketing data used were obtained from two independent marketing studies which were made available on confidentiality basis. Nevertheless, the data used are believed to be fairly accurate with respect to the market potential.

  17. Education Program on Fossil Resources Including Coal

    NASA Astrophysics Data System (ADS)

    Usami, Masahiro

    Fossil fuels including coal play a key role as crucial energies in contributing to economic development in Asia. On the other hand, its limited quantity and the environmental problems causing from its usage have become a serious global issue and a countermeasure to solve such problems is very much demanded. Along with the pursuit of sustainable development, environmentally-friendly use of highly efficient fossil resources should be therefore, accompanied. Kyushu-university‧s sophisticated research through long years of accumulated experience on the fossil resources and environmental sectors together with the advanced large-scale commercial and empirical equipments will enable us to foster cooperative research and provide internship program for the future researchers. Then, this program is executed as a consignment business from the Ministry of Economy, Trade and Industry from 2007 fiscal year to 2009 fiscal year. The lecture that uses the textbooks developed by this program is scheduled to be started a course in fiscal year 2010.

  18. Cerium anomaly at microscale in fossils.

    PubMed

    Gueriau, Pierre; Mocuta, Cristian; Bertrand, Loïc

    2015-09-01

    Patterns in rare earth element (REE) concentrations are essential instruments to assess geochemical processes in Earth and environmental sciences. Excursions in the "cerium anomaly" are widely used to inform on past redox conditions in sediments. This proxy resources to the specificity of cerium to adopt both the +III and +IV oxidation states, while most rare earths are purely trivalent and share very similar reactivity and transport properties. In practical terms, the level of cerium anomaly is established through elemental point quantification and profiling. All these models rely on a supposed homogeneity of the cerium oxidation state within the samples. However, this has never been demonstrated, whereas the cerium concentration can significantly vary within a sample, as shown for fossils, which would vastly complicate interpretation of REE patterns. Here, we report direct micrometric mapping of Ce speciation through synchrotron X-ray absorption spectroscopy and production of local rare earth patterns in paleontological fossil tissues through X-ray fluorescence mapping. The sensitivity of the approach is demonstrated on well-preserved fishes and crustaceans from the Late Cretaceous (ca. 95 million years (Myr) old). The presence of Ce under the +IV form within the fossil tissues is attributed to slightly oxidative local conditions of burial and agrees well with the limited negative cerium anomaly observed in REE patterns. The [Ce(IV)]/[Ce(tot)] ratio appears remarkably stable at the microscale within each fossil and is similar between fossils from the locality. Speciation maps were obtained from an original combination of synchrotron microbeam X-ray fluorescence, absorption spectroscopy, and diffraction, together with light and electron microscopy. This work also highlights the need for more systematic studies of cerium geochemistry at the microscale in paleontological contexts, in particular across fossil histologies.

  19. Atmospheric composition as a potential taphonomic filter for the fossil leaf record

    NASA Astrophysics Data System (ADS)

    Bacon, Karen; Haworth, Matthew; McElwain, Jennifer

    2016-04-01

    Controlled environment chambers provide a unique opportunity to investigate plant responses to simulated palaeoatmospheric compositions that reflect previous periods of Earth history. One potentially important role of atmospheric composition that has not been considered in detail, is how it may affect plant preservation in the fossil record. Previous work has shown that plants, particularly angiosperms, have a tendency to increase leaf mass per area (LMA) when grown in above-ambient CO2. We tested the response of six nearest living equivalent taxa for Mesozoic floras to a range of simulated Mesozoic palaeoatmospheric treatments in controlled environment chambers. Exposure to high CO2 (~1,500 ppm) led to a statistically significant (p < 0.001) increase in LMA in four out of 6 species and exposure to high CO2 and low O2 (~13%) led to a statistically significant (p < 0.001) increase in LMA in all six species. These findings suggest that atmospheric composition has a highly significant impact on LMA. If this is also the case in fossil floras, then this suggests that atmospheric composition may influence leaf preservation potential in the fossil record. Based on these results, we put forward the hypothesis that atmospheric composition is an important taphonomic filter of the fossil leaf record. Further research is now required to test the significance of atmospheric composition versus other well-known taphonomic filters.

  20. Relative importance of thermal versus carbon dioxide induced warming from fossil-fuel combustion

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Caldeira, K.

    2015-12-01

    The Earth is heated both when reduced carbon is oxidized to carbon dioxide and when outgoing longwave radiation is trapped by carbon dioxide in the atmosphere (CO2 greenhouse effect). The purpose of this study is to improve our understanding of time scales and relative magnitudes of climate forcing increase over time from pulse, continuous, and historical CO2 and thermal emissions. To estimate the amount of global warming that would be produced by thermal and CO2 emissions from fossil fuel combustion, we calculate thermal emissions with thermal contents of fossil fuels and estimate CO2 emissions with emission factors from Intergovernmental Panel on Climate Change (IPCC) AR5. We then use a schematic climate model mimicking Coupled Model Intercomparison Project Phase 5 to investigate the climate forcing and the time-integrated climate forcing. We show that, considered globally, direct thermal forcing from fossil fuel combustion is about 1.71% the radiative forcing from CO2 that has accumulated in the atmosphere from past fossil fuel combustion. When a new power plant comes on line, the radiative forcing from the accumulation of released CO2 exceeds the thermal emissions from the power plant in less than half a year (and about 3 months for coal plants). Due to the long lifetime of CO2 in the atmosphere, CO2 radiative forcing greatly overwhelms direct thermal forcing on longer time scales. Ultimately, the cumulative radiative forcing from the CO2 exceeds the direct thermal forcing by a factor of ~100,000.

  1. Fossils of parasites: what can the fossil record tell us about the evolution of parasitism?

    PubMed

    Leung, Tommy L F

    2017-02-01

    Parasites are common in many ecosystems, yet because of their nature, they do not fossilise readily and are very rare in the geological record. This makes it challenging to study the evolutionary transition that led to the evolution of parasitism in different taxa. Most studies on the evolution of parasites are based on phylogenies of extant species that were constructed based on morphological and molecular data, but they give us an incomplete picture and offer little information on many important details of parasite-host interactions. The lack of fossil parasites also means we know very little about the roles that parasites played in ecosystems of the past even though it is known that parasites have significant influences on many ecosystems. The goal of this review is to bring attention to known fossils of parasites and parasitism, and provide a conceptual framework for how research on fossil parasites can develop in the future. Despite their rarity, there are some fossil parasites which have been described from different geological eras. These fossils include the free-living stage of parasites, parasites which became fossilised with their hosts, parasite eggs and propagules in coprolites, and traces of pathology inflicted by parasites on the host's body. Judging from the fossil record, while there were some parasite-host relationships which no longer exist in the present day, many parasite taxa which are known from the fossil record seem to have remained relatively unchanged in their general morphology and their patterns of host association over tens or even hundreds of millions of years. It also appears that major evolutionary and ecological transitions throughout the history of life on Earth coincided with the appearance of certain parasite taxa, as the appearance of new host groups also provided new niches for potential parasites. As such, fossil parasites can provide additional data regarding the ecology of their extinct hosts, since many parasites have

  2. Insect diversity in the fossil record

    NASA Technical Reports Server (NTRS)

    Labandeira, C. C.; Sepkoski, J. J. Jr; Sepkoski JJ, J. r. (Principal Investigator)

    1993-01-01

    Insects possess a surprisingly extensive fossil record. Compilation of the geochronologic ranges of insect families demonstrates that their diversity exceeds that of preserved vertebrate tetrapods through 91 percent of their evolutionary history. The great diversity of insects was achieved not by high origination rates but rather by low extinction rates comparable to the low rates of slowly evolving marine invertebrate groups. The great radiation of modern insects began 245 million years ago and was not accelerated by the expansion of angiosperms during the Cretaceous period. The basic trophic machinery of insects was in place nearly 100 million years before angiosperms appeared in the fossil record.

  3. Microbial Fossils Detected in Desert Varnish

    NASA Technical Reports Server (NTRS)

    Flood, B. E.; Allen, C.; Longazo, T.

    2003-01-01

    Mars Global Surveyor Thermal Emission Spectrometer data indicate regions with significant levels of hematite (_Fe2O3). Fe-oxides, like hematite, can form as aqueous mineral precipitates and as such may preserve microscopic fossils or other biosignatures. Several potential terrestrial analogues to martian hematite like hydrothermal vents have preserved microfossils. Microbial fossilization in Fe-oxides is often a function of biomineralization. For example, goethite (FeO2H) encrustation of fungal mycelia from the mid-Tertiary preserved fungal morphologies such that their genera could be determined.

  4. Aquatic ape theory and fossil hominids.

    PubMed

    Verhaegen, M J

    1991-06-01

    While most older palaeo-anthropological studies emphasise the similarities of the fossil hominids with modern man, recent studies often stress the unique and the apelike features of the australopithecine dentitions, skulls and postcranial bones. It is worth reconsidering the features of Australopithecus, Homo erectus and Homo neanderthalensis in the light of the so-called Aquatic Ape Theory (AAT) of Hardy and Morgan, and to compare the skeletal parts of our fossil relatives with those of (semi)aquatic animals. Possible convergences are observed with proboscis monkeys, beavers, sea-otters, hippopotamuses, seals, sea-lions, walruses, sea-cows, whales, dolphins, porpoises, penguins and crocodiles.

  5. Fossils, Genes and The Origin of Organs

    SciTech Connect

    Shubin, Neil

    2011-04-20

    A toolkit of experimental and comparative biology can be applied to understand the great transformations in the history of life. Expeditionary paleontology can be used to target key nodes of the tree of life for which new fossils can provide insights into major morphological transformations. These fossils often have intermediate conditions that allow extant creatures to be compared in new ways. The tools of developmental genetics can then be used to explore these new comparisons to understand the genetic basis for macroevolutionary change. These different approaches can be used to predict new discoveries and this is only possible because of the empirical content of the tree of life.

  6. Are pollen fossils useful for calibrating relaxed molecular clock dating of phylogenies? A comparative study using Myrtaceae.

    PubMed

    Thornhill, Andrew H; Popple, Lindsay W; Carter, Richard J; Ho, Simon Y W; Crisp, Michael D

    2012-04-01

    The identification and application of reliable fossil calibrations represents a key component of many molecular studies of evolutionary timescales. In studies of plants, most paleontological calibrations are associated with macrofossils. However, the pollen record can also inform age calibrations if fossils matching extant pollen groups are found. Recent work has shown that pollen of the myrtle family, Myrtaceae, can be classified into a number of morphological groups that are synapomorphic with molecular groups. By assembling a data matrix of pollen morphological characters from extant and fossil Myrtaceae, we were able to measure the fit of 26 pollen fossils to a molecular phylogenetic tree using parsimony optimisation of characters. We identified eight Myrtaceidites fossils as appropriate for calibration based on the most parsimonious placements of these fossils on the tree. These fossils were used to inform age constraints in a Bayesian phylogenetic analysis of a sequence alignment comprising two sequences from the chloroplast genome (matK and ndhF) and one nuclear locus (ITS), sampled from 106 taxa representing 80 genera. Three additional analyses were calibrated by placing pollen fossils using geographic and morphological information (eight calibrations), macrofossils (five calibrations), and macrofossils and pollen fossils in combination (12 calibrations). The addition of new fossil pollen calibrations led to older crown ages than have previously been found for tribes such as Eucalypteae and Myrteae. Estimates of rate variation among lineages were affected by the choice of calibrations, suggesting that the use of multiple calibrations can improve estimates of rate heterogeneity among lineages. This study illustrates the potential of including pollen-based calibrations in molecular studies of divergence times.

  7. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia since the turn of the century.

    PubMed

    O'Sullivan, M; Rap, A; Reddington, C L; Spracklen, D V; Gloor, M; Buermann, W

    2016-08-16

    The global terrestrial carbon sink has increased since the start of this century at a time of growing carbon emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning enhanced the diffuse light fraction and the efficiency of plant carbon uptake. Using a combination of models, we estimate that at global scale changes in light regimes from fossil fuel aerosol emissions had only a small negative effect on the increase in terrestrial net primary production over the period 1998-2010. Hereby, the substantial increases in fossil fuel aerosol emissions and plant carbon uptake over East Asia were effectively canceled by opposing trends across Europe and North America. This suggests that if the recent increase in the land carbon sink would be causally linked to fossil fuel emissions, it is unlikely via the effect of aerosols but due to other factors such as nitrogen deposition or nitrogen-carbon interactions.

  8. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia since the turn of the century

    NASA Astrophysics Data System (ADS)

    O'Sullivan, M.; Rap, A.; Reddington, C. L.; Spracklen, D. V.; Gloor, M.; Buermann, W.

    2016-08-01

    The global terrestrial carbon sink has increased since the start of this century at a time of growing carbon emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning enhanced the diffuse light fraction and the efficiency of plant carbon uptake. Using a combination of models, we estimate that at global scale changes in light regimes from fossil fuel aerosol emissions had only a small negative effect on the increase in terrestrial net primary production over the period 1998-2010. Hereby, the substantial increases in fossil fuel aerosol emissions and plant carbon uptake over East Asia were effectively canceled by opposing trends across Europe and North America. This suggests that if the recent increase in the land carbon sink would be causally linked to fossil fuel emissions, it is unlikely via the effect of aerosols but due to other factors such as nitrogen deposition or nitrogen-carbon interactions.

  9. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia since the turn of the century

    PubMed Central

    Rap, A.; Reddington, C. L.; Spracklen, D. V.; Gloor, M.; Buermann, W.

    2016-01-01

    Abstract The global terrestrial carbon sink has increased since the start of this century at a time of growing carbon emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning enhanced the diffuse light fraction and the efficiency of plant carbon uptake. Using a combination of models, we estimate that at global scale changes in light regimes from fossil fuel aerosol emissions had only a small negative effect on the increase in terrestrial net primary production over the period 1998–2010. Hereby, the substantial increases in fossil fuel aerosol emissions and plant carbon uptake over East Asia were effectively canceled by opposing trends across Europe and North America. This suggests that if the recent increase in the land carbon sink would be causally linked to fossil fuel emissions, it is unlikely via the effect of aerosols but due to other factors such as nitrogen deposition or nitrogen‐carbon interactions. PMID:27773953

  10. New hominid fossils from Member 1 of the Swartkrans formation, South Africa.

    PubMed

    Pickering, Travis Rayne; Heaton, Jason L; Clarke, Ronald J; Sutton, Morris B; Brain, C K; Kuman, Kathleen

    2012-05-01

    Member 1 of the Swartkrans Formation is comprised of two sedimentary infills, the Lower Bank (LB) and the Hanging Remnant (HR). Together, the LB and HR preserve fossils of early Homo and Paranthropus robustus, Earlier Stone Age lithic artifacts, purported bone digging tools and butchered animal bones. Collectively, this evidence was the first to establish the co-existence of two early Pleistocene hominid species and also led to inferences of plant root harvesting and meat-eating by one or both of those species. P. robustus is the more abundant of the two hominids at Swartrkrans, represented in Member 1 by hundreds of fossils that derive from at least 99 individuals. Thus, Swartkrans Member 1 stands as the world's single largest repository of that extinct species. Here we add to the Member 1 sample of hominid fossils with descriptions of 14 newly discovered specimens.

  11. Influence of Past Changes in Atmospheric CO2 on Boron/Calcium of Planktic Fossil Foraminifera

    NASA Astrophysics Data System (ADS)

    Domeyko, R. A.; Allen, K. A.; deMenocal, P. B.

    2014-12-01

    Culture experiments have revealed that B/Ca of shells grown by the foraminiferal species Globigerinoides ruber increase with increasing seawater pH. Specifically, B/Ca responds to changes in the relative abundance of pH-sensitive dissolved carbon and boron species (Allen et al. 2011, 2012). Here, we present a high-resolution study on fossilized G. ruber from two sites in North Atlantic subtropical gyres (VM25-21 and ODP 1055B) through 20 ka BP to evaluate how B/Ca responds to past changes in atmospheric CO2. Forams were picked and crushed gently, then cleaned and dissolved using a variation of the Boyle and Keigwin (1985) and Barker et al. (2003) cleaning protocols prior to analysis. ODP 1055B (from Carolina Slope, West Atlantic) produced a high-resolution record with lower B/Ca values during the glacial period followed by a rapid shift to higher B/Ca values in the early deglaciation, with values remaining high through the Holocene. These results were not predicted by culture calibrations, but they are consistent with B/Ca records from the Caribbean (ODP 999, Foster et al. 2008), suggesting this pattern is characteristic of surface waters in the greater North Atlantic region.

  12. Innovative Fresh Water Production Process for Fossil Fuel Plants

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight

    2006-09-29

    This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report summarizes the progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. Detailed heat and mass transfer analyses required to size and analyze the diffusion tower using a heated water input are described. The analyses agree quite well with the current data and the information available in the literature. The direct contact condenser has also been thoroughly analyzed and the system performance at optimal operating conditions has been considered using a heated water/ambient air input to the diffusion tower. The diffusion tower has also been analyzed using a heated air input. The DDD laboratory facility has successfully been modified to include an air heating section. Experiments have been conducted over a range of parameters for two different cases: heated air/heated water and heated air/ambient water. A theoretical heat and mass transfer model has been examined for both of these cases and agreement between the experimental and theoretical data is good. A parametric study reveals that for every liquid mass flux there is an air mass flux value where the diffusion tower energy consumption is minimal and an air mass flux where the fresh water production flux is maximized. A study was also performed to compare the DDD process with different inlet operating conditions as well as different packing. It is shown that the heated air/heated water case is more capable of greater fresh water production with the same energy consumption than the ambient air/heated water process at high liquid mass flux. It is also shown that there can be significant advantage when using the heated air/heated water process with a less dense less specific surface area packed bed. Use of one configuration over the other depends upon the environment and the desired operating conditions.

  13. Proceedings: Fourth international conference on fossil plant cycle chemistry

    SciTech Connect

    Dooley, R.B.; Pate, S.R.

    1995-01-01

    The objectives of the conference were to review, document and transfer technology on all aspects of cycle chemistry. To meet these objectives, papers were presented and are included in these proceedings in ten technical areas: Boiler Related Chemistry; Feedwater Related Chemistry; International Cycle Chemistry; Instrumentation and Diagnostics; Steam; Ion Exchange and Condensate Polishing; Chemical Cleaning; Oxygenated Treatment; Cycle Effects; and Cycle Chemistry Improvement and Management Programs. Each topic at the conference was discussed in a separate session and these discussions are also included in the proceedings following each paper. The mix of international and domestic papers were chosen to indicate the marked differences in practices and to stimulate discussion. The working group summaries provided some of this flavor; they also indicate the current needs and deficiencies and outline R and D required to improve/upgrade cycle chemistry. The results of a comprehensive survey conducted at the conference are also included. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  14. Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants

    SciTech Connect

    Carl R. Evenson; Richard N. Kleiner; James E. Stephan; Frank E. Anderson

    2006-01-31

    During this quarter of the no cost extension a cermet composition referred to as EC101 containing a high permeability metal and a ceramic phase was prepared for sealing and permeability testing. Several different types of seals were developed and tested. In addition membrane surface stability was characterized.

  15. The Quality of the Fossil Record: Populations, Species, and Communities

    NASA Astrophysics Data System (ADS)

    Kidwell, Susan M.; Flessa, Karl W.

    Paleontologists have always been concerned about the documentary quality of the fossil record, and this has also become an important issue for biologists, who increasingly look to accumulations of bones, shells, and plant material as possible ways to extend the time-frame of observation on species and community behaviors. Quantitative data on the postmortem behavior of organic remains in modern environments are providing new insights into death and fossil assemblages as sources of biological information. Important findings include: 1. With the exception of a few circumstances, usually recognizable by independent criteria, transport out of the original life habitat affects few individuals. 2. Most species with preservable hard-parts are in fact represented in the local death assemblage, commonly in correct rank importance. Molluscs are the most durable of modern aquatic groups studied so far, and they show highest fidelity to the original community. 3. Time-averaging of remains from successive generations and communities often prevents the detection of short term (seasons, years) variability but provides an excellent record of the natural range of community composition and structure over longer periods. Thus, although a complex array of processes and circumstances influences preservation, death assemblages of resistant skeletal elements are for many major groups good to excellent records of community composition, morphological variation, and environmental and geographic distribution of species, and such assemblages can record dynamics at ecologically and evolutionarily meaningful scales.

  16. Fossil Cores In The Kepler Data

    NASA Astrophysics Data System (ADS)

    Jackson, Brian

    Most gas giant exoplanets with orbital periods < few days are unstable against tidal decay and may be tidally disrupted before their host stars leave the main sequence. These gas giants probably contain rocky/icy cores, and so their cores will be stranded near their progenitor's Roche limit (few hours orbital period). These fossil cores will evade the Kepler mission's transit search because it is focused on periods > 0.5 days, but finding these fossil cores would provide unprecedented insights into planetary interiors and formation ? e.g., they would be a smoking gun favoring formation of gas giants via core accretion. We propose to search for and characterize fossil cores in the Kepler dataset. We will vet candidates using the Kepler photometry and auxiliary data, collect ground-based spectra of the host stars and radial-velocity (RV) and adaptive optics (AO) data to corroborate candidates. We will also constrain stellar tidal dissipation efficiencies (parameterized by Q) by determining our survey's completeness, elucidating dynamical origins and evolution of exoplanets even if we find no fossil cores. Our preliminary search has already found several dozen candidates, so the proposed survey has a high likelihood of success.

  17. Fossil Crustaceans as Parasites and Hosts.

    PubMed

    Klompmaker, Adiël A; Boxshall, Geoff A

    2015-01-01

    Numerous crustacean lineages have independently moved into parasitism as a mode of life. In modern marine ecosystems, parasitic crustaceans use representatives from many metazoan phyla as hosts. Crustaceans also serve as hosts to a rich diversity of parasites, including other crustaceans. Here, we show that the fossil record of such parasitic interactions is sparse, with only 11 examples, one dating back to the Cambrian. This may be due to the limited preservation potential and small size of parasites, as well as to problems with ascribing traces to parasitism with certainty, and to a lack of targeted research. Although the confirmed stratigraphic ranges are limited for nearly every example, evidence of parasitism related to crustaceans has become increasingly more complete for isopod-induced swellings in decapods so that quantitative analyses can be carried out. Little attention has yet been paid to the origin of parasitism in deep time, but insight can be generated by integrating data on fossils with molecular studies on modern parasites. In addition, there are other traces left by parasites that could fossilize, but have not yet been recognized in the fossil record.

  18. Fossils of reionization in the local group

    SciTech Connect

    Gnedin, Nickolay Y.; Kravtsov, Andrey V.; /KICP, Chicago /Chicago U., EFI /Chicago U., Astron. Astrophys. Ctr.

    2006-01-01

    We use a combination of high-resolution gas dynamics simulations of high-redshift dwarf galaxies and dissipationless simulations of a Milky Way sized halo to estimate the expected abundance and spatial distribution of the dwarf satellite galaxies that formed most of their stars around z {approx} 8 and evolved only little since then. Such galaxies can be considered as fossils of the reionization era, and studying their properties could provide a direct window into the early, pre-reionization stages of galaxy formation. We show that 5-15% of the objects existing at z {approx} 8 do indeed survive until the present in the MW like environment without significant evolution. This implies that it is plausible that the fossil dwarf galaxies do exist in the Local Group. Because such galaxies form their stellar systems early during the period of active merging and accretion, they should have spheroidal morphology regardless of their current distance from the host galaxy. We show that both the expected luminosity function and spatial distribution of dark matter halos which are likely to host fossil galaxies agree reasonably well with the observed distributions of the luminous (L{sub V} > 10{sup 6} Lsun) Local Group fossil candidates near the host galaxy (d<200 kpc). However, the predicted abundance is substantially larger (by a factor of 2-3) for fainter galaxies (L{sub V} < 10{sup 6} Lsun) at larger distances (d>300 kpc). We discuss several possible explanations for this discrepancy.

  19. The Fascinating Story of Fossil Fuels

    ERIC Educational Resources Information Center

    Asimov, Isaac

    1973-01-01

    How this energy source was created, its meaning to mankind, our drastically reduced supply, and why we cannot wait for nature to make more are considered. Today fossil fuels supply 96 percent of the energy used but we must find alternate energy options if we are to combat the energy crisis. (BL)

  20. Fossil Energy Materials Program conference proceedings

    SciTech Connect

    Judkins, R.R.

    1987-08-01

    The US Department of Energy Office of Fossil Energy has recognized the need for materials research and development to assure the adequacy of materials of construction for advanced fossil energy systems. The principal responsibility for identifying needed materials research and for establishing a program to address these needs resides within the Office of Technical Coordination. That office has established the Advanced Research and Technology Development (AR and TD) Fossil Energy Materials Program to fulfill that responsibility. In addition to the AR and TD Materials Program, which is designed to address in a generic way the materials needs of fossil energy systems, specific materials support activities are also sponsored by the various line organizations such as the Office of Coal Gasification. A conference was held at Oak Ridge, Tennessee on May 19-21, 1987, to present and discuss the results of program activities during the past year. The conference program was organized in accordance with the research thrust areas we have established. These research thrust areas include structural ceramics (particularly fiber-reinforced ceramic composites), corrosion and erosion, and alloy development and mechanical properties. Eighty-six people attended the conference. Papers have been entered individually into EDB and ERA. (LTN)

  1. Paranasal pneumatization in extant and fossil Cercopithecoidea.

    PubMed

    Rae, Todd C

    2008-03-01

    Unlike most primates, extant cercopithecoids lack maxillary sinuses, which are pneumatic spaces in the facial skeleton lateral of the nasal cavity proper. Character state analysis of living cercopithecoids across well-supported topologies suggests that the sinus was lost at the origin of the superfamily, only to have evolved again convergently in extant macaques. Recent work has shown that a) the 'early loss' hypothesis is supported by the lack of any pneumatization in Victoriapithecus, a stem cercopithecoid, b) like extant macaques, the fossil cercopithecine Paradolichopithecus shows evidence of presence of the maxillary sinus (MS), and c) unlike extant colobines, the fossil colobine Libypithecus also possesses a maxillary sinus. To more fully assess the pattern of cercopithecoid sinus evolution, fossil taxa from both subfamilies (Colobinae, Cercopithecinae) were examined both visually and by computed tomography (CT). The observations were evaluated according to standard anatomical criteria for defining sinus spaces, and compared with data from all extant Old World monkey genera. Most taxa examined conformed to the pattern already discerned from extant cercopithecoids. Maxillary sinus absence in Theropithecus oswaldi, Mesopithecus, and Rhinocolobus is typical for all extant cercopithecids except Macaca. The fossil macaque Macaca majori possesses a well-developed maxillary sinus, as do all living species of the genus. Cercopithecoides, on the other hand, differs from all extant colobines in possessing a maxillary sinus. Thus, paranasal pneumatization has reemerged a minimum of two and possibly three times in cercopithecoids. The results suggest that maxillary sinus absence in cercopithecoids is due to suppression, rather than complete loss.

  2. On the fossil record of the Gekkota.

    PubMed

    Daza, Juan D; Bauer, Aaron M; Snively, Eric D

    2014-03-01

    Gekkota is often interpreted as sister to all remaining squamates, exclusive of dibamids, or as sister to Autarchoglossa. It is the only diverse lineage of primarily nocturnal lizards and includes some of the smallest amniotes. The skeleton of geckos has often been interpreted as paedomorphic and/or "primitive" but these lizards also display a wide range of structural specializations of the postcranium, including modifications associated with both scansorial locomotion and limb reduction. Although the concept of "Gekkota" has been variously applied by different authors, we here apply a rigorous apomorphy based definition, recent advances in gekkotan morphology and phylogenetics, and diverse comparative material to provide a comprehensive assessment of 28 known pre-Quaternary geckos, updating the last such review, published three decades ago. Fossils evaluated include both sedimentary fossils and amber-embedded specimens. Known Cretaceous geckos are exclusively Asian and exhibit character combinations not seen in any living forms. Cenozoic gekkotans derive from sites around the world, although Europe is especially well represented. Paleogene geckos are largely known from disarticulated remains and show similarities to Sphaerodactylidae and Diplodactylidae, although resemblances may be plesiomorphic in some cases. Many Neogene gekkotans are referable to living families or even genera, but their geographic occurrences are often extralimital to those of modern groups, as is consistent with paleoclimatic conditions. The phylogenetic placement of fossil gekkotans has important repercusions for timetree calibration, but at present only a small number of fossils can be confidently assigned to even family level groupings, limiting their utility in this regard.

  3. Solid modeling of fossil small mammal teeth

    NASA Astrophysics Data System (ADS)

    Marschallinger, Robert; Hofmann, Peter; Daxner-Höck, Gudrun; Ketcham, Richard A.

    2011-09-01

    This paper presents an approach to create solid models of fossil small mammal teeth using a combination of microcomputed tomography, object based image analysis and voxel modeling. Small mammal teeth, because of their durability, are widely found in Cenozioc sediments the world over and play a key role in stratigraphy as well as in researching the rapid evolution and the paleogeographic spreading of small mammals. Recent advances in microcomputed tomography make this non-destructive analysis method an ideal data source for high-resolution 3D models of fossil small animal teeth. To derive internally consistent solid models of such fossils from micro-CT imagery, we propose a combination of 3D object based image analysis and solid modeling. Incorporating paleontological expert knowledge in the image processing cycle, object based image analysis yields topologically consistent image stacks classified by the main tooth components—enamel, dentine and pulp. Forwarding these data to a voxel modeling system, they can be quantitatively analyzed in an unprecedented manner: going beyond the possibilities of the state-of-art surface models, solid models are capable of unambiguously portraying the entire object volume—teeth can be peeled by material properties, subvolumes can be extracted and automatically analyzed by Boolean operations. The proposed method, which can be flexibly extended to handle a range of paleontological and geological micro-objects, is demonstrated with two typical fossil small mammal teeth.

  4. Geoscience: Fossil raindrops and ancient air

    NASA Astrophysics Data System (ADS)

    Cassata, William S.; Renne, Paul R.

    2012-04-01

    An analysis of fossil imprints of ancient raindrops suggests that the density of the atmosphere 2.7 billion years ago was much the same as that today. This result casts fresh light on a long-standing palaeoclimate paradox. See Letter p.359

  5. Learning about Fossil Formation by Classroom Simulation.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.; Yoshida, Sarah J.

    1991-01-01

    Activities in which students build their own simulations of fossils, using seashells, chicken bones, toy dinosaurs, or leaves as models and plaster of paris, sand, mud, clay, or a mixture of gravel and clay as a matrix are presented. Curriculum extensions are included. (KR)

  6. Thermal dissolution of solid fossil fuels

    SciTech Connect

    E.G. Gorlov

    2007-10-15

    The use of oil shales and coals in the processes of thermal dissolution is considered. It is shown that thermal dissolution is a mode of liquefaction of solid fossil fuels and can be used both independently and in combination with liquefaction of coals and processing of heavy petroleum residues.

  7. Fossil fuels supplies modeling and research

    SciTech Connect

    Leiby, P.N.

    1996-06-01

    The fossil fuel supplies modeling and research effort focuses on models for US Strategic Petroleum Reserve (SPR) planning and management. Topics covered included new SPR oil valuation models, updating models for SPR risk analysis, and fill-draw planning. Another task in this program area is the development of advanced computational tools for three-dimensional seismic analysis.

  8. Small global effect on terrestrial net primary production due to increased fossil fuel aerosol emissions from East Asia during the last decade.

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Michael; Rap, Alex; Reddington, Carly; Spracklen, Dominick; Buermann, Wolfgang

    2016-04-01

    The global terrestrial carbon sink has increased since the start of this century at a time of rapidly growing carbon dioxide emissions from fossil fuel burning. Here we test the hypothesis that increases in atmospheric aerosols from fossil fuel burning have increased the diffuse fraction of incoming solar radiation and the efficiency of photosynthesis leading to increased plant carbon uptake. Using a combination of atmospheric and biospheric models, we find that changes in diffuse light associated with fossil fuel aerosol emission accounts for only 2.8% of the increase in global net primary production (1.221 PgC/yr) over the study period 1998 to 2007. This relatively small global signal is however a result of large regional compensations. Over East Asia, the strong increase in fossil fuel emissions contributed nearly 70% of the increased plant carbon uptake (21 TgC/yr), whereas the declining fossil fuel aerosol emissions in Europe and North America contributed negatively (-16% and -54%, respectively) to increased plant carbon uptake. At global scale, we also find the CO2 fertilization effect on photosynthesis to be the dominant driver of increased plant carbon uptake, in line with previous studies. These results suggest that further research into alternative mechanisms by which fossil fuel emissions could increase carbon uptake, such as nitrogen deposition and carbon-nitrogen interactions, is required to better understand a potential link between the recent changes in fossil fuel emissions and terrestrial carbon uptake.

  9. Delta13C values of grasses as a novel indicator of pollution by fossil-fuel-derived greenhouse gas CO2 in urban areas.

    PubMed

    Lichtfouse, Eric; Lichtfouse, Michel; Jaffrézic, Anne

    2003-01-01

    A novel fossil fuel pollution indicator based on the 13C/12C isotopic composition of plants has been designed. This bioindicator is a promising tool for future mapping of the sequestration of fossil fuel CO2 into urban vegetation. Theoretically, plants growing in fossil-fuel-CO2-contaminated areas, such as major cities, industrial centers, and highway borders, should assimilate a mixture of global atmospheric CO2 of delta13C value of -8.02 per thousand and of fossil fuel CO2 of average delta13C value of -27.28 per thousand. This isotopic difference should, thus, be recorded in plant carbon. Indeed, this study reveals that grasses growing near a major highway in Paris, France, have strikingly depleted delta13C values, averaging at -35.08 per thousand, versus rural grasses that show an average delta13C value of -30.59 per thousand. A simple mixing model was used to calculate the contributions of fossil-fuel-derived CO2 to the plant tissue. Calculation based on contaminated and noncontaminated isotopic end members shows that urban grasses assimilate up to 29.1% of fossil-fuel-CO2-derived carbon in their tissues. The 13C isotopic composition of grasses thus represents a promising new tool for the study of the impact of fossil fuel CO2 in major cities.

  10. Diversity in obscurity: fossil flowers and the early history of angiosperms.

    PubMed

    Friis, Else Marie; Pedersen, Kaj Raunsgaard; Crane, Peter R

    2010-02-12

    In the second half of the nineteenth century, pioneering discoveries of rich assemblages of fossil plants from the Cretaceous resulted in considerable interest in the first appearance of angiosperms in the geological record. Darwin's famous comment, which labelled the 'rapid development' of angiosperms an 'abominable mystery', dates from this time. Darwin and his contemporaries were puzzled by the relatively late, seemingly sudden and geographically widespread appearance of modern-looking angiosperms in Late Cretaceous floras. Today, the early diversification of angiosperms seems much less 'rapid'. Angiosperms were clearly present in the Early Cretaceous, 20-30 Myr before they attained the level of ecological dominance reflected in some mid-Cretaceous floras, and angiosperm leaves and pollen show a distinct pattern of steadily increasing diversity and complexity through this interval. Early angiosperm fossil flowers show a similar orderly diversification and also provide detailed insights into the changing reproductive biology and phylogenetic diversity of angiosperms from the Early Cretaceous. In addition, newly discovered fossil flowers indicate considerable, previously unrecognized, cryptic diversity among the earliest angiosperms known from the fossil record. Lineages that today have an herbaceous or shrubby habit were well represented. Monocotyledons, which have previously been difficult to recognize among assemblages of early fossil angiosperms, were also diverse and prominent in many Early Cretaceous ecosystems.

  11. Exceptional fossil preservation and the cambrian explosion.

    PubMed

    Butterfield, Nicholas J

    2003-02-01

    Exceptionally preserved, non-biomineralizing fossils contribute importantly to resolving details of the Cambrian explosion, but little to its overall patterns. Six distinct "types" of exceptional preservation are identified for the terminal Proterozoic-Cambrian interval, each of which is dependent on particular taphonomic circumstances, typically restricted both in space and time. Taphonomic pathways yielding exceptional preservation were particularly variable through the Proterozoic-Cambrian transition, at least in part a consequence of contemporaneous evolutionary innovations. Combined with the reasonably continuous record of "Doushantuo-type preservation," and the fundamentally more robust records of shelly fossils, phytoplankton cysts and trace fossils, these taphonomic perturbations contribute to the documentation of major evolutionary and biogeochemical shifts through the terminal Proterozoic and early Cambrian.Appreciation of the relationship between taphonomic pathway and fossil expression serves as a useful tool for interpreting exceptionally preserved, often problematic, early Cambrian fossils. In shale facies, for example, flattened non-biomineralizing structures typically represent the remains of degradation-resistant acellular and extracellular "tissues" such as chaetae and cuticles, whereas three-dimensional preservation represents labile cellular tissues with a propensity for attracting and precipitating early diagenetic minerals. Such distinction helps to identify the acuticular integument of hyolithids, the chaetae-like nature of Wiwaxia sclerites, the chaetognath-like integument of Amiskwia, the midgut glands of various Burgess Shale arthropods, and the misidentification of deposit-feeding arthropods in the Chengjiang biota. By the same reasoning, putative lobopods in the Sirius Passet biota and putative deuterostomes in the Chengiang biota are better interpreted as arthropods.

  12. Van Allen Probes Mission Space Academy: Educating middle school students about Earth's mysterious radiation belts

    NASA Astrophysics Data System (ADS)

    Butler, L.; Turney, D.; Matiella Novak, A.; Smith, D.; Simon, M.

    2013-12-01

    How's the weather in space? Why on Earth did NASA send two satellites above Earth to study radiation belts and space weather? To learn the answer to questions about NASA's Van Allen Probes mission, 450 students and their teachers from Maryland middle schools attended Space Academy events highlighting the Van Allen Probes mission. Sponsored by the Applied Physics Laboratory (APL) and Discovery Education, the events are held at the APL campus in Laurel, MD. Space Academies take students and teachers on behind-the-scenes exploration of how spacecraft are built, what they are designed to study, and introduces them to the many professionals that work together to create some of NASA's most exciting projects. Moderated by a public relations representative in the format of an official NASA press conference, the daylong event includes a student press conference with students as reporters and mission experts as panelists. Lunch with mission team members gives students a chance to ask more questions. After lunch, students don souvenir clean room suits, enjoy interactive science demonstrations, and tour APL facilities where the Van Allen Probes were built and tested before launch. Students may even have an opportunity to peek inside a clean room to view spacecraft being assembled. Prior to the event, teachers are provided with classroom activities, lesson plans, and videos developed by APL and Discovery Education to help prepare students for the featured mission. The activities are aligned to National Science Education Standards and appropriate for use in the classroom. Following their visit, student journalists are encouraged to write a short article about their field trip; selections are posted on the Space Academy web site. Designed to engage, inspire, and influence attitudes about space science and STEM careers, Space Academies provide an opportunity to attract underserved populations and emphasize that space science is for everyone. Exposing students to a diverse group of

  13. Simultaneous Pi2 observations by the Van Allen Probes inside and outside the plasmasphere

    NASA Astrophysics Data System (ADS)

    Ghamry, E.; Kim, K.-H.; Kwon, H.-J.; Lee, D.-H.; Park, J.-S.; Choi, J.; Hyun, K.; Kurth, W. S.; Kletzing, C.; Wygant, J. R.; Huang, J.

    2015-06-01

    Plasmaspheric virtual resonance (PVR) model has been proposed as one of source mechanisms for low-latitude Pi2 pulsations. Since PVR-associated Pi2 pulsations are not localized inside the plasmasphere, simultaneous multipoint observations inside and outside the plasmasphere require to test the PVR model. Until now, however, there are few studies using simultaneous multisatellite observations inside and outside the plasmasphere for understanding the radial structure of Pi2 pulsation. In this study, we focus on the Pi2 event observed at low-latitude Bohyun (BOH, L = 1.35) ground station in South Korea in the postmidnight sector (magnetic local time (MLT) = 3.0) for the interval from 1730 to 1900 UT on 12 March 2013. By using electron density derived from the frequency of the upper hybrid waves detected at Van Allen Probe-A (VAP-A) and Van Allen Probe-B (VAP-B), the plasmapause is identified. At the time of the Pi2 event, VAP-A was outside the plasmasphere near midnight (00:55 MLT and L =˜ 6), while VAP-B was inside the plasmasphere in the postmidnight sector (02:15 MLT and L =˜ 5). VAP-B observed oscillations in the compressional magnetic field component (Bz) and the dawn-to-dusk electric field component (Ey), having high coherence with the BOH Pi2 pulsation in the H component. The H-Bz and H-Ey cross phases at VAP-B inside the plasmasphere were near -180° and -90°, respectively. These phase relationships among Bz, Ey, and H are consistent with a radially standing oscillation of the fundamental mode reported in previous studies. At VAP-A outside the plasmasphere, Bz oscillations were highly correlated with BOH Pi2 pulsations with ˜-180° phase delay, and the H-Ey cross phase is near -90°. From these two-satellite observations, we suggest that the fundamental PVR mode is directly detected by VAP-A and VAP-B.

  14. Time scales and ratios of climate forcing due to thermal versus carbon dioxide emissions from fossil fuels

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaochun; Caldeira, Ken

    2015-06-01

    The Earth warms both when fossil fuel carbon is oxidized to carbon dioxide and when greenhouse effect of carbon dioxide inhibits longwave radiation from escaping to space. Various important time scales and ratios comparing these two climate forcings have not previously been quantified. For example, the global and time-integrated radiative forcing from burning a fossil fuel exceeds the heat released upon combustion within 2 months. Over the long lifetime of CO2 in the atmosphere, the cumulative CO2-radiative forcing exceeds the amount of energy released upon combustion by a factor >100,000. For a new power plant, the radiative forcing from the accumulation of released CO2 exceeds the direct thermal emissions in less than half a year. Furthermore, we show that the energy released from the combustion of fossil fuels is now about 1.71% of the radiative forcing from CO2 that has accumulated in the atmosphere as a consequence of historical fossil fuel combustion.

  15. An early Oligocene fossil demonstrates treeshrews are slowly evolving "living fossils".

    PubMed

    Li, Qiang; Ni, Xijun

    2016-01-14

    Treeshrews are widely considered a "living model" of an ancestral primate, and have long been called "living fossils". Actual fossils of treeshrews, however, are extremely rare. We report a new fossil species of Ptilocercus treeshrew recovered from the early Oligocene (~34 Ma) of China that represents the oldest definitive fossil record of the crown group of treeshrews and nearly doubles the temporal length of their fossil record. The fossil species is strikingly similar to the living Ptilocercus lowii, a species generally recognized as the most plesiomorphic extant treeshrew. It demonstrates that Ptilocercus treeshrews have undergone little evolutionary change in their morphology since the early Oligocene. Morphological comparisons and phylogenetic analysis support the long-standing idea that Ptilocercus treeshrews are morphologically conservative and have probably retained many characters present in the common stock that gave rise to archontans, which include primates, flying lemurs, plesiadapiforms and treeshrews. This discovery provides an exceptional example of slow morphological evolution in a mammalian group over a period of 34 million years. The persistent and stable tropical environment in Southeast Asia through the Cenozoic likely played a critical role in the survival of such a morphologically conservative lineage.

  16. [Raman spectra of fossil dinosaurs from different regions].

    PubMed

    Yang, Qun; Wang, Yi-lin

    2007-12-01

    Raman microscopic spectra in the higher wave number region were obtained from 7 fossil dinosaurs specimens from different regions. The specimens of fossil dinosaurs are different parts of bone. The Raman spectra of fossil dinosaurs indicate the high similarity among peak positions of different fossil dinosaurs; but important differences exist in the spectral peak figures. In the wave number region of 1000-1800 cm(-1) the Raman spectra of the same bone part fossils from different regions are very similar, example similarities between spectra of Lufeing backbone head and Yua nmou backbone head; Lufeng limb bone and Wuding limb bone. There are relations between the same bone part spectra of different fossil dinosaurs. The characteristic does not relate to regions. Raman spectra of fossil dinosaurs cannot be used to distinguish fossil source, although the part of bone can be used as an indicator to narrow the range of possible geographical origins.

  17. Atmospheric Verification of Point Source Fossil Fuel CO2 Emissions

    NASA Astrophysics Data System (ADS)

    Turnbull, J. C.; Keller, E. D.; Norris, M. W.; Wiltshire, R.; Baisden, W. T.; Brailsford, G. W.; Bromley, T.

    2015-12-01

    Large point sources (electricity generation and large-scale industry) make up roughly one third of all fossil fuel CO2 (CO2ff) emissions. Currently, these emissions are determined from self-reported inventory data, and sometimes from smokestack emissions monitoring, and the uncertainty in emissions from individual power plants is about 20%. We examine the utility of atmospheric 14C measurements combined with atmospheric transport modelling as a tool for independently quantifying point source CO2ff emissions, to both improve the accuracy of the reported emissions and for verification as we move towards a regulatory environment. We use the Kapuni Gas Treatment Facility as a test case. It is located in rural New Zealand with no other significant fossil fuel CO2 sources nearby, and emits CO2ff at ~0.1 Tg carbon per year. We use several different sampling methods to determine the 14C and hence the CO2ff content downwind of the emission source: grab flask samples of whole air; absorption of CO2 into sodium hydroxide integrated over many hours; and plant material which faithfully records the 14C content of assimilated CO2. We use a plume dispersion model to compare the reported emissions with our observed CO2ff mole fractions. We show that the short-term variability in plume dispersion makes it difficult to interpret the grab flask sample results, whereas the variability is averaged out in the integrated samples and we obtain excellent agreement between the reported and observed emissions, indicating that the 14C method can reliably be used to evaluated point source emissions.

  18. An extreme distortion of the Van Allen belt arising from the 'Hallowe'en' solar storm in 2003.

    PubMed

    Baker, D N; Kanekal, S G; Li, X; Monk, S P; Goldstein, J; Burch, J L

    2004-12-16

    The Earth's radiation belts--also known as the Van Allen belts--contain high-energy electrons trapped on magnetic field lines. The centre of the outer belt is usually 20,000-25,000 km from Earth. The region between the belts is normally devoid of particles, and is accordingly favoured as a location for spacecraft operation because of the benign environment. Here we report that the outer Van Allen belt was compressed dramatically by a solar storm known as the 'Hallowe'en storm' of 2003. From 1 to 10 November, the outer belt had its centre only approximately 10,000 km from Earth's equatorial surface, and the plasmasphere was similarly displaced inwards. The region between the belts became the location of high particle radiation intensity. This remarkable deformation of the entire magnetosphere implies surprisingly powerful acceleration and loss processes deep within the magnetosphere.

  19. The role of ring current particle injections: Global simulations and Van Allen Probes observations during 17 March 2013 storm

    NASA Astrophysics Data System (ADS)

    Yu, Yiqun; Jordanova, Vania; Welling, Dan; Larsen, Brian; Claudepierre, Seth G.; Kletzing, Craig

    2014-02-01

    We simulate substorm injections observed by the Van Allen Probes during the 17 March 2013 storm using a self-consistent coupling between the ring current model RAM-SCB and the global MHD model BATS-R-US. This is a significant advancement compared to previous studies that used artificially imposed electromagnetic field pulses to mimic substorm dipolarization and associated inductive electric field. Several substorm dipolarizations and injections are reproduced in the MHD model, in agreement with the timing of shape changes in the AE/AL index. The associated inductive electric field transports plasma sheet plasma to geostationary altitudes, providing the boundary plasma source to the ring current model. It is found that impulsive plasma sheet injections, together with a large-scale convection electric field, are necessary to develop a strong ring current. Comparisons with Van Allen Probes observations show that our model reasonably well captures dispersed electron injections and the global Dst index.

  20. 77 FR 48960 - Foreign-Trade Zone 12-McAllen, TX Notification of Proposed Export Production Activity TST NA Trim...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... Activity TST NA Trim, LLC (Fabric/Leather Lamination and Cutting) Hidalgo, TX The McAllen Foreign Trade... TST NA Trim, LLC (TST), located in Hidalgo, Texas. The notification conforming to the requirements...

  1. The Global Positioning System constellation as a space weather monitor. Comparison of electron measurements with Van Allen Probes data

    DOE PAGES

    Morley, Steven K.; Sullivan, John P.; Henderson, Michael G.; ...

    2016-02-06

    Energetic electron observations in Earth's radiation belts are typically sparse, and multipoint studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross calibration into two parts—one that removes any spectral assumptions from the CXD flux calculation and one that compares the energy spectra—we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra, wemore » use a combination of four distributions that together capture a wide range of observed spectral shapes. Moreover, our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer and Relativistic Electron-Proton Telescope on Van Allen Probes as a “gold standard,” here we demonstrate that the CXD instruments are well understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies inline image4 MeV. Our team present data from 17 CXD-equipped GPS satellites covering the 2015 “St. Patrick's Day” geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting.« less

  2. A Useful Allene for the Stereoselective Synthesis of Protected Quaternary 2-Amino-2-vinyl-1,3-diols.

    PubMed

    Rodríguez, Aleix; Ariza, Xavier; Contreras, Miguel A; Garcia, Jordi; Lloyd-Williams, Paul; Mercadal, Nerea; Sánchez, Carolina

    2017-02-03

    Treatment of readily available allene 1 with Cy2BH followed by addition of an aldehyde led to quaternary protected 2-amino-2-vinyl-1,3-diols in high yield and excellent stereochemical purity. The choice of benzoyl as N-protecting group is critical since the observed N- to O-Bz transfer during the process prevents later undesired isomerizations in the adducts and keeps all heteroatoms protected.

  3. Enantioselective Generation of Adjacent Stereocenters in a Copper‐Catalyzed Three‐Component Coupling of Imines, Allenes, and Diboranes

    PubMed Central

    Yeung, Kay; Ruscoe, Rebecca E.; Rae, James; Pulis, Alexander P.

    2016-01-01

    Abstract A highly enantio‐ and diastereoselective copper‐catalyzed three‐component coupling affords the first general synthesis of homoallylic amines bearing adjacent stereocenters from achiral starting materials. The method utilizes a commercially available NHC ligand and copper source, operates at ambient temperature, couples readily available simple imines, allenes, and diboranes, and yields high‐value homoallylic amines that exhibit versatile amino, alkenyl, and boryl units. PMID:27539673

  4. The Global Positioning System constellation as a space weather monitor. Comparison of electron measurements with Van Allen Probes data

    SciTech Connect

    Morley, Steven K.; Sullivan, John P.; Henderson, Michael G.; Blake, J. Bernard; Baker, Daniel N.

    2016-02-06

    Energetic electron observations in Earth's radiation belts are typically sparse, and multipoint studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross calibration into two parts—one that removes any spectral assumptions from the CXD flux calculation and one that compares the energy spectra—we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra, we use a combination of four distributions that together capture a wide range of observed spectral shapes. Moreover, our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer and Relativistic Electron-Proton Telescope on Van Allen Probes as a “gold standard,” here we demonstrate that the CXD instruments are well understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies inline image4 MeV. Our team present data from 17 CXD-equipped GPS satellites covering the 2015 “St. Patrick's Day” geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting.

  5. Allen's big-eared bat (Idionycteris phyllotis) documented in colorado based on recordings of its distinctive echolocation call

    USGS Publications Warehouse

    Hayes, M.A.; Navo, K.W.; Bonewell, L.; Mosch, C.J.; Adams, R.A.

    2009-01-01

    Allen's big-eared bat (Idionycteris phyllotis) inhabits much of the southwestern USA, but has not been documented in Colorado. We recorded echolocation calls consistent with I. phyllotis near La Sal Creek, Montrose County, Colorado. Based on characteristics of echolocation calls and flight behavior, we conclude that the echolocation calls described here were emitted by I. phyllotis and that they represent the first documentation of this species in Colorado.

  6. Fossil DNA as a Recorder of Ancient Microbial Communities and Palaeoenvironments

    NASA Astrophysics Data System (ADS)

    Coolen, M. J.; Boere, A.; Abbas, B.; Muyzer, G.; Overmann, J.; Wakeham, S. G.; Volkman, J. K.; Sinninghe Damste, J. S.

    2005-12-01

    . Furthermore, we will discuss examples which show the relevance of the identification of the ancient aquatic microbial community members at the unprecedented species-level using fossil rDNA as a novel palaeoproxy. (1) Coolen, MJL., et al., Combined DNA and lipid analyses of sediments reveal changes in Holocene haptophyte and diatom populations in an Antarctic lake , Earth. Planet. Sc. Lett., 223, 225-239, 2004. (2) Coolen, MJL and J. Overmann, Analysis of subfossil molecular remains of purple sulfur bacteria in a lake sediment, Appl. Environ. Microbiol., 64(11), 4513-4521, 1998. (3) Willerslev, E., et al. Diverse plant and animal genetic records from Holocene and Pleistocene sediments, Science, 300(5620), 791-795, 2003.

  7. Van Allen Probes ECT/MagEIS Background Corrected Electron Flux Measurements: Methods and Initial Findings

    NASA Astrophysics Data System (ADS)

    Claudepierre, S. G.; O'Brien, T. P., III; Blake, J. B.; Fennell, J.; Looper, M. D.; Clemmons, J. H.; Roeder, J. L.; Mazur, J. E.; Mulligan, T. L.

    2014-12-01

    We present results from the Magnetic Electron Ion Spectrometer (MagEIS) instrument, part ofthe Energetic Composition and Thermal Plasma (ECT) Suite, onboard the NASA Van AllenProbes spacecraft. The ECT/MagEIS instrument measures radiation belt electrons in the ~20-4000 keV energy range and protons in the ~60-1000 keV energy range, with high resolution inboth energy and pitch-angle. In addition, the MagEIS electron measurement technique allowsfor a full quantification of the source(s) of background contamination in the measurement.MagEIS is thus able to make clean, reliable electron flux observations in the presence of strongpenetrating backgrounds, for example, contamination from relativistic protons in the inner zoneand inner slot region. We summarize our background correction algorithm, describe the varioussources of background contamination, and present an overview of our initial findings using thebackground corrected data set. Understanding the causes and effects of backgroundcontamination in the MagEIS electron data set is crucial for the interpretation and proper use ofsuch data. The techniques described will facilitate new investigations into the dynamics of theEarth's electron radiation belts, which have thus far not been possible.

  8. Automated Determination of Electron Density from Electric Field Measurements on the Van Allen Probes Spacecraft

    NASA Astrophysics Data System (ADS)

    Zhelavskaya, I. S.; Spasojevic, M.; Shprits, Y.

    2015-12-01

    In this study we present an algorithm for automatic inference of the electron number density from plasma wave measurement made onboard NASA's Van Allen Probes mission. It accomplishes this by using feedforward neural networks to automatically infer the upper hybrid resonance frequency, 𝑓𝑢h𝑟, from plasma wave measurement, which is then used to determine the electron number density. In previous missions, the plasma resonance bands were manually identified, and there have been few attempts to do robust, routine automated detection (Kurth et al. [JGR, 2014]). We describe the design and implementation of the algorithm, as well as the resulting electron number density distribution. Resulting densities are compared with the densities obtained by Kurth et al. [JGR, 2014] and also to the empirical plasmasphere and trough density model of Sheeley et al. [JGR, 2001]. The analysis of the conditions, under which densities obtained by the proposed method differ significantly from the model of Sheeley et al. [JGR, 2001], is presented. Finally, we discuss the dependence of the electron number density on magnetic activity (Kp) and magnetic local time.

  9. Inner magnetosphere plasma, statistics from the Van Allen Probes HOPE instrument and data release 3.

    NASA Astrophysics Data System (ADS)

    Larsen, B.; Skoug, R. M.; Olson, D. K.; Reeves, G.; Friedel, R. H.; Funsten, H. O.

    2015-12-01

    As the twin Van Allen probes spacecraft complete three years on-orbit more than a complete revolution in local time has occurred. We present the state of the HOPE plasma data and statistics of the plasma distribution inside of geostationary orbit. Over the course of the mission a better understanding of the instrument has been gained and the needed corrections added to the data to enable long-term statistics to be collected and compared with confidence. The major correction to the data is the expected degradation of the channel electron multiplier (CEM) efficiency as a function of time and count rate. HOPE provides background data sufficient to monitor the absolute detection efficiency throughout the mission. We have incorporated a time dependent gain correction factor to the data that normalizes the gain and thus the derived plasma properties. In addition the CEM bias voltage was adjusted bringing the gain back toward launch values. With a standard set of data electron and ion composition statistics are computed and presented. These statistics serve as a L-MLT dependent distribution to begin inner magnetosphere plasma modeling, instrument comparison, and climatology studies. These data are presented as ECT HOPE release 3.

  10. Inner magnetosphere plasma, statistics from the Van Allen Probes HOPE instrument and data release 3.

    NASA Astrophysics Data System (ADS)

    Lotko, W.; Smith, R. H.; Zhang, B.; Ouellette, J.; Brambles, O.; Lyon, J.; Wiltberger, M. J.

    2014-12-01

    As the twin Van Allen probes spacecraft complete three years on-orbit more than a complete revolution in local time has occurred. We present the state of the HOPE plasma data and statistics of the plasma distribution inside of geostationary orbit. Over the course of the mission a better understanding of the instrument has been gained and the needed corrections added to the data to enable long-term statistics to be collected and compared with confidence. The major correction to the data is the expected degradation of the channel electron multiplier (CEM) efficiency as a function of time and count rate. HOPE provides background data sufficient to monitor the absolute detection efficiency throughout the mission. We have incorporated a time dependent gain correction factor to the data that normalizes the gain and thus the derived plasma properties. In addition the CEM bias voltage was adjusted bringing the gain back toward launch values. With a standard set of data electron and ion composition statistics are computed and presented. These statistics serve as a L-MLT dependent distribution to begin inner magnetosphere plasma modeling, instrument comparison, and climatology studies. These data are presented as ECT HOPE release 3.

  11. Comparison between Low and High Latitude Lightning VLF Wave Propagation Using WWLLN and Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zheng, H.; Holzworth, R. H., II; Brundell, J. B.; Wygant, J. R.; Hospodarsky, G. B.; Mozer, F.; Jacobson, A. R.; Bonnell, J. W.

    2014-12-01

    Lightning produces strong broadband radio waves, called "sferics", which propagate in the Earth-ionosphere waveguide and are detected thousands of kilometers away from their source. Global real-time detection of lightning strokes including their time, location and energy, is conducted with the World Wide Lightning Location Network (WWLLN). In the ionosphere, these sferics couple into very low frequency (VLF) whistler waves which propagate obliquely to the Earth's magnetic field. Possible one-to-one coincidence between lightning and VLF whistler wave is already found by the conjunction work between WWLLN and Van Allen Probes (formerly known as the Radiation Belt Storm Probes (RBSP)). The previous global study showed a good match between WWLLN sferics and RBSP VLF whistlers at low L shell region (L < 3). In this summer, we started obtaining high sampling mode data from RBSP near the apogee. Initial results indicate many one-to-one coincidences at high L shell region (L>4). The whistlers observed at high L shell region are often nose whistlers. In our work, we will show the statistics results between WWLLN sferics and RBSP VLF whistlers at high L shell region. This talk will also explore the difference between low and high latitude lightning VLF wave propagation.

  12. Revealing the generation of extremely low frequency chorus in Van Allen radiation belts

    DOE PAGES

    Xiao, Fuliang; Liu, Si; Tao, Xin; ...

    2017-03-02

    Recent studies have shown that chorus can efficiently accelerate the outer radiation belt electrons to relativistic energies. Chorus, previously often observed above 0.1 equatorial electron gyrofrequency fce, was generated by energetic electrons originating from Earth's plasmasheet. Chorus below 0.1 fce has seldom been reported until the recent data from Van Allen Probes but its origin has not been revealed so far. Because electron resonant energy can approach the relativistic level at extremely low frequency relativistic effects should be considered in the formula for whistler-mode wave growth rate. Here we report high-resolution observations during the 14 October 2014 small storm andmore » firstly demonstrate, using a fully relativistic simulation, that electrons with the high energy tail population and relativistic pitch angle anisotropy can provide free energy sufficient for generating chorus below 0.1 fce. The simulated wave growth displays a very similar pattern to the observations. Finally, the current results can be applied to Jupiter, Saturn and other magnetized planets.« less

  13. Wave-driven butterfly distribution of Van Allen belt relativistic electrons

    DOE PAGES

    Xiao, Fuliang; Yang, Chang; Su, Zhenpeng; ...

    2015-10-05

    Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day–night asymmetry in Earth’s magnetic field. However, direct observation of a butterfly distribution well inside of geostationary orbit and the origin of this phenomenon have not been provided so far. Here we report high-resolution observation that a unusual butterfly pitch angle distribution of relativistic electrons occurred within 5 Earth radii during the 28more » June 2013 geomagnetic storm. In conclusion, simulation results show that combined acceleration by chorus and magnetosonic waves can successfully explain the electron flux evolution both in the energy and butterfly pitch angle distribution. Finally, the current provides a great support for the mechanism of wave-driven butterfly distribution of relativistic electrons.« less

  14. Understanding Earth's radiation belt electron dynamics: Van Allen Probes observations and simulations

    NASA Astrophysics Data System (ADS)

    Li, Wen; Ma, Qianli; Thorne, Richard; Bortnik, Jacob; Zhang, Xiaojia

    2016-10-01

    Various physical processes are known to cause acceleration, loss, and transport of energetic electrons in the Earth's radiation belts, but their quantitative roles in different time and space need further investigation. In the present paper, we evaluate the relative roles of various physical processes during geomagnetic storms using a 3D diffusion simulation. By quantitatively comparing the electron evolution observed by Van Allen Probes and simulation, we found that whistler-mode chorus waves play a critical role in accelerating electrons up to several MeV through efficient energy diffusion. By only including radial diffusion driven by ultra-low-frequency waves, the simulation underestimates the observed electron acceleration, while radial diffusion plays an important role in redistributing electrons. Although an additional loss process is required to fully explain the overestimated electron fluxes at multi-MeV, the combined physical processes of radial diffusion and scattering by whistler-mode waves reproduce the observed electron dynamics remarkably well, suggesting that quasi-linear diffusion theory is reasonable to evaluate radiation belt electron dynamics, and the importance of nonlinear wave-particle interaction may still remain as an open question. We would like to acknowledge AFOSR Award FA9550-15-1-0158, NASA Grants NNX15AI96G, NNX15AF61G, and the NSF Grant AGS 1564510 for supporting this research.

  15. A long-lived relativistic electron storage ring embedded in Earth's outer Van Allen belt.

    PubMed

    Baker, D N; Kanekal, S G; Hoxie, V C; Henderson, M G; Li, X; Spence, H E; Elkington, S R; Friedel, R H W; Goldstein, J; Hudson, M K; Reeves, G D; Thorne, R M; Kletzing, C A; Claudepierre, S G

    2013-04-12

    Since their discovery more than 50 years ago, Earth's Van Allen radiation belts have been considered to consist of two distinct zones of trapped, highly energetic charged particles. The outer zone is composed predominantly of megaelectron volt (MeV) electrons that wax and wane in intensity on time scales ranging from hours to days, depending primarily on external forcing by the solar wind. The spatially separated inner zone is composed of commingled high-energy electrons and very energetic positive ions (mostly protons), the latter being stable in intensity levels over years to decades. In situ energy-specific and temporally resolved spacecraft observations reveal an isolated third ring, or torus, of high-energy (>2 MeV) electrons that formed on 2 September 2012 and persisted largely unchanged in the geocentric radial range of 3.0 to ~3.5 Earth radii for more than 4 weeks before being disrupted (and virtually annihilated) by a powerful interplanetary shock wave passage.

  16. Estimates of trapped radiation encountered on low-thrust trajectories through the Van Allen belts

    NASA Technical Reports Server (NTRS)

    Karp, I. M.

    1973-01-01

    Estimates were made of the number of trapped protons and electrons encountered by vehicles on low-thrust trajectories through the Van Allen belts. The estimates serve as a first step in assessing whether these radiations present a problem to on-board sensitive components and payload. The integrated proton spectra and electron spectra are presented for the case of a trajectory described by a vehicle with a constant-thrust acceleration A sub c equal to 0.001 meter/sq sec. This value of acceleration corresponds to a trip time of about 54 days from low earth orbit to synchronous orbit. It is shown that the time spent in the belts and hence the radiation encountered vary nearly inversely with the value of thrust acceleration. Thus, the integrated spectral values presented for the case of A sub c = 0.001 meter/sq sec can be generalized for any other value of thrust acceleration by multiplying them by the factor 0.001/A sub c.

  17. The seasonal dependence of relativistic electron fluxes in the Earth's outer van Allen Belt

    NASA Astrophysics Data System (ADS)

    Kanekal, S. G.; Baker, D. N.; McPherron, R.

    2007-12-01

    It is well known that geomagnetic activity shows a marked seasonal dependence. This effect has been attributed to the seasonal variation of the Earth's dipole tilt angle exposing the magnetosphere to an increased southward component of the interplanetary field (the Russell-McPherron effect) or an increased solar wind velocity (the axial/equinoctial effect). We examine the seasonal dependence of relativistic electron fluxes in the Earth's outer Van Allen belt. An earlier investigation by Baker et. al., (1999) found that the relativistic electron fluxes do show a strong seasonal dependence with the equinoctial electron fluxes being almost three times higher than the solstitial fluxes. We extend this previous investigation using data obtained by sensors onboard SAMPEX. This study of the seasonal dependence is based on data with a higher time resolution as compared to the earlier study. The results of our analysis show that the peak electron fluxes are shifted in time from the nominal equinoctial times. We discuss some possible implications of our observations in the context of electron energization in the Earth's magnetosphere. Baker, D.N., S.G. Kanekal, T.I. Pulkkinen, and J.B. Blake, Equinoctial and solstitial averages of magnetospheric relativistic electrons: A strong semiannual modulation, Geophys. Res. Lett., 26, No. 20, 3193-3196, 1999.

  18. Aromatic Osmacyclopropenefuran Bicycles and Their Relevance for the Metal-Mediated Hydration of Functionalized Allenes.

    PubMed

    Batuecas, María; Castro-Rodrigo, Ruth; Esteruelas, Miguel A; García-Yebra, Cristina; López, Ana M; Oñate, Enrique

    2016-10-24

    The aromatic osmacyclopropenefuran bicycles [OsTp{κ(3) -C(1) ,C(2) ,O-(C(1) H2 C(2) CHC(OEt)O)}(P(i) Pr3 )]BF4 (Tp=hydridotris(1-pyrazolyl)borate) and [OsH{κ(3) -C(1) ,C(2) ,O-(C(1) H2 C(2) CHC(OEt)O)}(CO)(P(i) Pr3 )2 ]BF4 , with the metal fragment in a common vertex between the fused three- and five-membered rings, have been prepared via the π-allene intermediates [OsTp(η(2) -CH2 =CCHCO2 Et)(OCMe2 )(P(i) Pr3 )]BF4 and [OsH(η(2) -CH2 =CCHCO2 Et)(CO)(OH2 )(P(i) Pr3 )2 ]BF4 , and their aromaticity analyzed by DFT calculations. The bicycle containing the [OsH(CO)(P(i) Pr3 )2 ](+) metal fragment is a key intermediate in the [OsH(CO)(OH2 )2 (P(i) Pr3 )2 ]BF4 -catalyzed regioselective anti-Markovnikov hydration of ethyl buta-2,3-dienoate to ethyl 4-hydroxycrotonate.

  19. Statistical Features of EMIC Waves Observed on Van Allen Probes in the Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Lee, D. Y.; Roh, S. J.; Cho, J.; Shin, D. K.; Hwang, J.; Kim, K. C.; Kurth, W. S.; Kletzing, C.; Wygant, J. R.; Thaller, S. A.

    2015-12-01

    Electromagnetic ion cyclotron (EMIC) waves are one of the key plasma waves that can affect charged particle dynamics in the Earth's inner magnetosphere. Knowledge of global distribution of the EMIC waves is critical for accurately assessing the significance of its interaction with charged particles. With the Van Allen Probes EMFISIS observations, we have surveyed EMIC events for ~2.5 years period. We have identified well-defined, banded wave activities only, as distinguished from broad band wave activities. We have obtained global distribution of occurrence of the identified waves with distinction between H- and He-bands. We compare it with previous observations such as THEMIS and CRRES. For the identified events we have drawn all the basic wave properties including wave frequency, polarization, wave normal angle. In addition, we have distinguished the EMIC events that occur inside the plasmasphere and at the plasmapause from those outside the plasmasphere. Finally, we have tested solar wind and geomagnetic dependence of the wave events. We give discussions about implications of these observations on wave generation mechanism and interaction with radiation belt electrons.

  20. Variation of energetic electron flux in Earth's radiation belts based on Van Allen Probes observations

    NASA Astrophysics Data System (ADS)

    Tang, Rongxin; Zhong, Zhihong; Yu, Deyin

    2016-04-01

    The Earth's radiation belts have been an important research topic of solar-terrestrial physics from 1958. In 2012, Van Allen Probes (VAP) were launched into near-equatorial orbit and provide very good in-situ observations of energetic particles in inner magnetosphere. Since magnetospheric substorm can cause the severe disturbance of the Earth's megnetospheric environment, here we focus on the characteristics of energetic electron fluxes in the radiation belts during substorm time and non-storm time. Energetic electron data observed by the Magnetic Electron Ion Spectrometer (MagEIS) and Energetic Particle Composition and Thermal Plasma Suite (ECT) of VAP during 2012 to 2014 are carefully analyzed. We select portions of energetic electron data from substorm onset phase, growth phase, recovery phase, and quiet time, and make a comparisons with theoretical computations. We find that the electron differential fluxes present E-1 shape at lower energies (<1MeV), and have a sharp transition with steeper slopes at high energies for large L-shells, which are in coincidence with Mauk's model [Mauk et al., 2010].

  1. “Trunk-like” heavy ion structures observed by the Van Allen Probes

    DOE PAGES

    Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; ...

    2015-10-27

    Dynamic ion spectral features in the inner magnetosphere are the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. Here, we report “trunk-like” ion structures observed by the Van Allen Probes on 2 November 2012. This new type of ion structure looks like an elephant's trunk on an energy-time spectrogram, with the energy of the peak flux decreasing Earthward. The trunks are present in He+ and O+ ions but not in H+. During the event, ion energies in the He+ trunk, located at L=3.6–2.6, magnetic local time (MLT)=9.1–10.5, and magnetic latitude (MLAT) =-2.4–0.09°, vary monotonically from 3.5more » to 0.04 keV. Values at the two end points of the O+ trunk are energy=4.5–0.7keV, L=3.6–2.5, MLT=9.1–10.7, and MLAT=-2.4–0.4°. Our results from backward ion drift path tracings indicate that the trunks are likely due to (1) a gap in the nightside ion source or (2) greatly enhanced impulsive electric fields associated with elevated geomagnetic activity. Different ion loss lifetimes cause the trunks to differ among ion species.« less

  2. Study of lightning whistler waves observed at high L-shells on Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zheng, H.; Holzworth, R.; Brundell, J. B.; Wygant, J. R.; Hospodarsky, G. B.; Mozer, F.; Jacobson, A. R.; Bonnell, J. W.

    2015-12-01

    Lightning produces strong broadband radio waves, called "sferics", which propagate in the Earth-ionosphere waveguide and are detected thousands of kilometers away from their source. Global real-time detection of lightning strokes including their time, location and energy, is conducted with the World Wide Lightning Location Network (WWLLN). In the ionosphere, these sferics couple into very low frequency (VLF) whistler waves which propagate obliquely to the Earth's magnetic field. In our previous work, one-to-one coincidence between lightning and whistler waves is already found by the conjunction work between WWLLN and Van Allen Probes (formerly known as the Radiation Belt Storm Probes (RBSP)). The previous global study showed a good match between WWLLN sferics and RBSP lightning whistlers at low L-shell region (L < 3). More case studies indicated that this kind of one-to-one coincidence can be extended to a high L-shell region. Since September 2012 to now (July 2015), EMFISIS instrument has already recorded 3-D waveform data with 35 ksamples/s for 527,279 and 542,346 of 6-second snapshots, respectively for RBSP-A and RBSP-B. 461,572 and 478,510 of snapshots with L-shell value larger than 3 are used in our work. In our work, we will show the distribution of lightning whistler waves at high L-shells. This talk will also explore the upper cutoff frequency of lightning whistler waves at high L-shells.

  3. "Trunk-like" heavy ion structures observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Zhang, J.-C.; Kistler, L. M.; Spence, H. E.; Wolf, R. A.; Reeves, G.; Skoug, R.; Funsten, H.; Larsen, B. A.; Niehof, J. T.; MacDonald, E. A.; Friedel, R.; Ferradas, C. P.; Luo, H.

    2015-10-01

    Dynamic ion spectral features in the inner magnetosphere are the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. We report "trunk-like" ion structures observed by the Van Allen Probes on 2 November 2012. This new type of ion structure looks like an elephant's trunk on an energy-time spectrogram, with the energy of the peak flux decreasing Earthward. The trunks are present in He+ and O+ ions but not in H+. During the event, ion energies in the He+ trunk, located at L = 3.6-2.6, magnetic local time (MLT) = 9.1-10.5, and magnetic latitude (MLAT) = -2.4-0.09°, vary monotonically from 3.5 to 0.04 keV. The values at the two end points of the O+ trunk are energy = 4.5-0.7 keV, L = 3.6-2.5, MLT = 9.1-10.7, and MLAT = -2.4-0.4°. Results from backward ion drift path tracings indicate that the trunks are likely due to (1) a gap in the nightside ion source or (2) greatly enhanced impulsive electric fields associated with elevated geomagnetic activity. Different ion loss lifetimes cause the trunks to differ among ion species.

  4. A background correction algorithm for Van Allen Probes MagEIS electron flux measurements

    SciTech Connect

    Claudepierre, S. G.; O'Brien, T. P.; Blake, J. B.; Fennell, J. F.; Roeder, J. L.; Clemmons, J. H.; Looper, M. D.; Mazur, J. E.; Mulligan, T. M.; Spence, H. E.; Reeves, G. D.; Friedel, R. H. W.; Henderson, M. G.; Larsen, B. A.

    2015-07-14

    We describe an automated computer algorithm designed to remove background contamination from the Van Allen Probes Magnetic Electron Ion Spectrometer (MagEIS) electron flux measurements. We provide a detailed description of the algorithm with illustrative examples from on-orbit data. We find two primary sources of background contamination in the MagEIS electron data: inner zone protons and bremsstrahlung X-rays generated by energetic electrons interacting with the spacecraft material. Bremsstrahlung X-rays primarily produce contamination in the lower energy MagEIS electron channels (~30–500 keV) and in regions of geospace where multi-M eV electrons are present. Inner zone protons produce contamination in all MagEIS energy channels at roughly L < 2.5. The background-corrected MagEIS electron data produce a more accurate measurement of the electron radiation belts, as most earlier measurements suffer from unquantifiable and uncorrectable contamination in this harsh region of the near-Earth space environment. These background-corrected data will also be useful for spacecraft engineering purposes, providing ground truth for the near-Earth electron environment and informing the next generation of spacecraft design models (e.g., AE9).

  5. Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt

    DOE PAGES

    Mann, I. R.; Ozeke, L. G.; Murphy, K. R.; ...

    2016-06-20

    Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging is understanding the recently discovered ultra-relativistic third electron radiation belt. Current theory asserts that loss in the heart of the outer belt, essential to the formation of the third belt, must be controlled by high-frequency plasma wave–particle scattering into the atmosphere, via whistler mode chorus, plasmaspheric hiss, or electromagnetic ion cyclotron waves. However, this has failed to accurately reproduce the third belt. In this paper, using a data-driven, time-dependent specification of ultra-low-frequency (ULF) waves we showmore » for the first time how the third radiation belt is established as a simple, elegant consequence of storm-time extremely fast outward ULF wave transport. High-frequency wave–particle scattering loss into the atmosphere is not needed in this case. Finally, when rapid ULF wave transport coupled to a dynamic boundary is accurately specified, the sensitive dynamics controlling the enigmatic ultra-relativistic third radiation belt are naturally explained.« less

  6. Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt

    SciTech Connect

    Mann, I. R.; Ozeke, L. G.; Murphy, K. R.; Claudepierre, S. G.; Turner, D. L.; Baker, D. N.; Rae, I. J.; Kale, A.; Milling, D. K.; Boyd, A. J.; Spence, H. E.; Reeves, Geoffrey D.; Singer, H. J.; Dimitrakoudis, S.; Daglis, I. A.; Honary, F.

    2016-06-20

    Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging is understanding the recently discovered ultra-relativistic third electron radiation belt. Current theory asserts that loss in the heart of the outer belt, essential to the formation of the third belt, must be controlled by high-frequency plasma wave–particle scattering into the atmosphere, via whistler mode chorus, plasmaspheric hiss, or electromagnetic ion cyclotron waves. However, this has failed to accurately reproduce the third belt. In this paper, using a data-driven, time-dependent specification of ultra-low-frequency (ULF) waves we show for the first time how the third radiation belt is established as a simple, elegant consequence of storm-time extremely fast outward ULF wave transport. High-frequency wave–particle scattering loss into the atmosphere is not needed in this case. Finally, when rapid ULF wave transport coupled to a dynamic boundary is accurately specified, the sensitive dynamics controlling the enigmatic ultra-relativistic third radiation belt are naturally explained.

  7. A background correction algorithm for Van Allen Probes MagEIS electron flux measurements

    DOE PAGES

    Claudepierre, S. G.; O'Brien, T. P.; Blake, J. B.; ...

    2015-07-14

    We describe an automated computer algorithm designed to remove background contamination from the Van Allen Probes Magnetic Electron Ion Spectrometer (MagEIS) electron flux measurements. We provide a detailed description of the algorithm with illustrative examples from on-orbit data. We find two primary sources of background contamination in the MagEIS electron data: inner zone protons and bremsstrahlung X-rays generated by energetic electrons interacting with the spacecraft material. Bremsstrahlung X-rays primarily produce contamination in the lower energy MagEIS electron channels (~30–500 keV) and in regions of geospace where multi-M eV electrons are present. Inner zone protons produce contamination in all MagEIS energymore » channels at roughly L < 2.5. The background-corrected MagEIS electron data produce a more accurate measurement of the electron radiation belts, as most earlier measurements suffer from unquantifiable and uncorrectable contamination in this harsh region of the near-Earth space environment. These background-corrected data will also be useful for spacecraft engineering purposes, providing ground truth for the near-Earth electron environment and informing the next generation of spacecraft design models (e.g., AE9).« less

  8. Can You Hear Me Now? Software Development at the Allen Telescope Array

    NASA Astrophysics Data System (ADS)

    Castellanos, Aaron; Harp, G.

    2013-01-01

    The Allen Telescope Array (ATA) is a 42 radio dish array located in Hat Creek, CA and is used to search for traces of Extraterrestrial Intelligence (SETI) and to study the interstellar medium. In order to minimize the Radio Frequency Interference (RFI) that leaks into the antennas of the ATA and gain a stronger signal along with a clearer picture of the sky, we must analyze the array to determine which antennas are operating best. Readgains is a new tool that we developed to generate the system temperatures of the dishes and if they are below a given threshold (e.g. 150 K), we use them for observations. We conducted a five week observation of the galaxy 3c286 in order to study the behavior of the array and concluded that most operating antennas are performing well and the ones that were not will be excluded in the next observations. Hat Creek Radio Observatory will continue to use this tool for continuous analysis of the array.

  9. Pulsating aurora observed on the ground and in-situ by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Lessard, M.; Cohen, I. J.; Denton, R. E.; Engebretson, M. J.; Kletzing, C.; Wygant, J. R.; Bounds, S. R.; Smith, C. W.; MacDowall, R. J.; Kurth, W. S.

    2013-12-01

    Early observations and theory related to pulsating aurora suggested that the electrons that drive this aurora originate from the equatorial region of the magnetosphere and that a likely process that can scatter these electrons would involve chorus waves. Recent satellite observations during pulsating auroral events have provided important "firsts", including evidence of strong correlations between pulsating auroral patches and in-situ lower-band chorus (THEMIS), as well as correlations with energetic electron precipitation in the vicinity of geosynchronous orbit (GOES). These results provide important information regarding particle dynamics, leading to a question about how the chorus might be driven. We present observations of the Van Allen Probes in conjunction with a pulsating aurora event, as confirmed by observations on the ground. The in-situ data again show the presence of lower-band chorus. However, magnetic and electric field data also show that the wave bursts coincide with an apparent poloidal field-line resonance, begging the question of whether the resonance might be responsible for driving the VLF waves.

  10. ACE EPAM and Van Allen Probes RBSPICE measurements of interplanetary oxygen injection to the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Patterson, J. D.; Manweiler, J. W.; Gerrard, A. J.; Lanzerotti, L. J.

    2015-12-01

    On March 17, 2015, a significant oxygen-rich interplanetary event was measure by the Advanced Composition Explorer (ACE) Electron Proton Alpha Monitor (EPAM) instrument. At the same time the Van Allen Probes Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instrument recorded significant enhancements of oxygen in the inner magnetosphere. We present a detailed analysis of this event utilizing a new method of exploiting the EPAM Pulse Height Analyzer (PHA) data to precisely resolve helium and oxygen spectra within the 0.5 to 5 MeV/nuc range. We also present the flux, partial particle pressures, and pitch angle distributions of the ion measurements from RBSPICE. During this event, both EPAM and RBSPICE measured O:He ratios greater than 10:1. The pitch angle distributions from RBSPICE-B show a strong beam of oxygen at an L ~ 5.8 early on March 17th during orbit. The timing between the observations of the oxygen peak at ACE and the beam observed at RBSPICE-B is consistent with the travel-time required for energetic particle transport from L1 to Earth and access to the magnetosphere. We assert that the oxygen seen by RBSPICE during the initial phase of this event is the result of direct injection from the interplanetary medium of energetic ions. This poster contains the observations and detailed calculations to support this assertion.

  11. Improved lattice Boltzmann modeling of binary flow based on the conservative Allen-Cahn equation

    NASA Astrophysics Data System (ADS)

    Ren, Feng; Song, Baowei; Sukop, Michael C.; Hu, Haibao

    2016-08-01

    The primary and key task of binary fluid flow modeling is to track the interface with good accuracy, which is usually challenging due to the sharp-interface limit and numerical dispersion. This article concentrates on further development of the conservative Allen-Cahn equation (ACE) [Geier et al., Phys. Rev. E 91, 063309 (2015), 10.1103/PhysRevE.91.063309] under the framework of the lattice Boltzmann method (LBM), with incorporation of the incompressible hydrodynamic equations [Liang et al., Phys. Rev. E 89, 053320 (2014), 10.1103/PhysRevE.89.053320]. Utilizing a modified equilibrium distribution function and an additional source term, this model is capable of correctly recovering the conservative ACE through the Chapman-Enskog analysis. We also simulate four phase-tracking benchmark cases, including one three-dimensional case; all show good accuracy as well as low numerical dispersion. By coupling the incompressible hydrodynamic equations, we also simulate layered Poiseuille flow and the Rayleigh-Taylor instability, illustrating satisfying performance in dealing with complex flow problems, e.g., high viscosity ratio, high density ratio, and high Reynolds number situations. The present work provides a reliable and efficient solution for binary flow modeling.

  12. A long-lived relativistic electron storage ring embedded in Earth's Outer Van Allen belt

    DOE PAGES

    Baker, D. N.; Kanekal, S. G.; Hoxie, V. C.; ...

    2013-02-28

    Since their discovery over 50 years ago, the Earth’s Van Allen radiation belts are thought to consist of two distinct zones of trapped, highly energetic charged particles. The outer zone is comprised predominantly of mega-electron volt (MeV) electrons that wax and wane in intensity on time scales ranging from hours to days depending primarily on external forcing by the solar wind. Thus, the spatially separated inner zone is comprised of commingled high-energy electrons and very energetic positive ions (mostly protons), the latter being stable in intensity levels over years to decades. In situ energy-specific and temporally resolved spacecraft observations revealmore » an isolated third ring, or torus, of high-energy (E > 2 MeV) electrons that formed on 2 September 2012 and persisted largely unchanged in the geocentric radial range of 3.0 to ~3.5 Earth radii for over four weeks before being disrupted (and virtually annihilated) by a powerful interplanetary shock wave passage.« less

  13. “Trunk-like” heavy ion structures observed by the Van Allen Probes

    SciTech Connect

    Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Wolf, R. A.; Reeves, G.; Skoug, R.; Funsten, H.; Larsen, B. A.; Niehof, J. T.; MacDonald, E. A.; Friedel, R.; Ferradas, C. P.; Luo, H.

    2015-10-27

    Dynamic ion spectral features in the inner magnetosphere are the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. Here, we report “trunk-like” ion structures observed by the Van Allen Probes on 2 November 2012. This new type of ion structure looks like an elephant's trunk on an energy-time spectrogram, with the energy of the peak flux decreasing Earthward. The trunks are present in He+ and O+ ions but not in H+. During the event, ion energies in the He+ trunk, located at L=3.6–2.6, magnetic local time (MLT)=9.1–10.5, and magnetic latitude (MLAT) =-2.4–0.09°, vary monotonically from 3.5 to 0.04 keV. Values at the two end points of the O+ trunk are energy=4.5–0.7keV, L=3.6–2.5, MLT=9.1–10.7, and MLAT=-2.4–0.4°. Our results from backward ion drift path tracings indicate that the trunks are likely due to (1) a gap in the nightside ion source or (2) greatly enhanced impulsive electric fields associated with elevated geomagnetic activity. Different ion loss lifetimes cause the trunks to differ among ion species.

  14. Cellular localization and detergent dependent oligomerization of rice allene oxide synthase-1.

    PubMed

    Yoeun, Sereyvath; Kim, Jeong-Il; Han, Oksoo

    2015-01-01

    Allene oxide synthase-1 from Oryza sativa (OsAOS1) localizes to the chloroplast, but lacks a putative chloroplast targeting sequence typically found in dicot AOS. Here, kinetic parameters and the oligomerization state/subunit composition of OsAOS1 were characterized in vitro in the absence or presence of detergent micelles. The catalytic efficiency (k(cat)/K(m)) of OsAOS1 reached a maximum near the critical micelle concentration for polyoxyethylene 10 tridecyl ether. Native gel analysis showed that OsAOS1 exists as a multimer in the absence of detergent micelles. The multimeric form of OsAOS1 was stably cross-linked in the absence of detergents, while only monomeric OsAOS1 was detected in the presence of detergent micelles. Gel filtration analysis indicated that the oligomeric state of OsAOS1 depends strongly on the detergents and that the monomer becomes the predominant form in the presence of detergent micelles. These data suggest that the detergent-dependent oligomeric state of OsAOS1 is an important factor for the regulation of its catalytic efficiency.

  15. New chorus wave properties near the equator from Van Allen Probes wave observations

    NASA Astrophysics Data System (ADS)

    Li, W.; Santolik, O.; Bortnik, J.; Thorne, R. M.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.

    2016-05-01

    The chorus wave properties are evaluated using Van Allen Probes data in the Earth's equatorial magnetosphere. Two distinct modes of lower band chorus are identified: a quasi-parallel mode and a quasi-electrostatic mode, whose wave normal direction is close to the resonance cone. Statistical results indicate that the quasi-electrostatic (quasi-parallel) mode preferentially occurs during relatively quiet (disturbed) geomagnetic activity at lower (higher) L shells. Although the magnetic intensity of the quasi-electrostatic mode is considerably weaker than the quasi-parallel mode, their electric intensities are comparable. A newly identified feature of the quasi-electrostatic mode is that its frequency peaks at higher values compared to the quasi-parallel mode that exhibits a broad frequency spectrum. Moreover, upper band chorus wave normal directions vary between 0° and the resonance cone and become more parallel as geomagnetic activity increases. Our new findings suggest that chorus-driven energetic electron dynamics needs a careful examination by considering the properties of these two distinct modes.

  16. Thermal conversions of fatty acid peroxides to cyclopentenones: a biomimetic model for allene oxide synthase pathway.

    PubMed

    Mukhtarova, Lucia S; Mukhitova, Fakhima K; Grechkin, Alexander N

    2013-01-01

    The trimethylsilyl (TMS) peroxides of linoleic acid 9(S)-hydroperoxide (TMS or Me esters) were subjected to gas chromatography-mass spectrometry (GC-MS) analyses. The cyclopentenones, trans- and cis-10-oxo-11-phytoenoic acid (10-oxo-PEA, Me or TMS esters) were first time detected as the products of TMS-peroxide thermal conversions. The major products were ketodienes, epoxyalcohols, hemiacetals and decadienals. For further study of thermal cyclopentenone formation, 9(S)- or 13(S)-hydroperoxides of linoleic acid (Me esters) were sealed in ampoules and heated at 230 °C for 15 or 30 min. The products were separated by HPLC. The cyclopentenone fractions were collected and analyzed by GC-MS. Trans-10-oxo-PEA (Me) and 10-oxo-9(13)-PEA (Me) were formed during the thermal conversion of 9-hydroperoxide (Me ester). Similarly, the cyclopentenones trans-12-oxo-PEA (Me) and 12-oxo-9(13)-PEA (Me) were detected after the heating of 13-hydroperoxide (Me ester). Thermal formation of cyclopentenones can be considered as a biomimetic model of AOS pathway, providing new insights into the mechanisms of allene oxide formation and cyclization.

  17. A long-lived relativistic electron storage ring embedded in Earth's Outer Van Allen belt

    SciTech Connect

    Baker, D. N.; Kanekal, S. G.; Hoxie, V. C.; Henderson, M. G.; Li, X.; Spence, H. E.; Elkington, S. R.; Friedel, R. H. W.; Goldstein, J.; Hudson, M. K.; Reeves, G. D.; Thorne, R. M.; Kletzing, C. A.; Claudepierre, S. G.

    2013-02-28

    Since their discovery over 50 years ago, the Earth’s Van Allen radiation belts are thought to consist of two distinct zones of trapped, highly energetic charged particles. The outer zone is comprised predominantly of mega-electron volt (MeV) electrons that wax and wane in intensity on time scales ranging from hours to days depending primarily on external forcing by the solar wind. Thus, the spatially separated inner zone is comprised of commingled high-energy electrons and very energetic positive ions (mostly protons), the latter being stable in intensity levels over years to decades. In situ energy-specific and temporally resolved spacecraft observations reveal an isolated third ring, or torus, of high-energy (E > 2 MeV) electrons that formed on 2 September 2012 and persisted largely unchanged in the geocentric radial range of 3.0 to ~3.5 Earth radii for over four weeks before being disrupted (and virtually annihilated) by a powerful interplanetary shock wave passage.

  18. "Zipper-like" periodic magnetosonic waves: Van Allen Probes, THEMIS, and magnetospheric multiscale observations

    NASA Astrophysics Data System (ADS)

    Li, J.; Bortnik, J.; Li, W.; Ma, Q.; Thorne, R. M.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Wygant, J.; Breneman, A.; Thaller, S.; Funsten, H. O.; Mitchell, D. G.; Manweiler, J. W.; Torbert, R. B.; Le Contel, O.; Ergun, R. E.; Lindqvist, P.-A.; Torkar, K.; Nakamura, R.; Andriopoulou, M.; Russell, C. T.

    2017-02-01

    An interesting form of "zipper-like" magnetosonic waves consisting of two bands of interleaved periodic rising-tone spectra was newly observed by the Van Allen Probes, the Time History of Events and Macroscale Interactions during Substorms (THEMIS), and the Magnetospheric Multiscale (MMS) missions. The two discrete bands are distinct in frequency and intensity; however, they maintain the same periodicity which varies in space and time, suggesting that they possibly originate from one single source intrinsically. In one event, the zipper-like magnetosonic waves exhibit the same periodicity as a constant-frequency magnetosonic wave and an electrostatic emission, but the modulation comes from neither density fluctuations nor ULF waves. A statistical survey based on 3.5 years of multisatellite observations shows that zipper-like magnetosonic waves mainly occur on the dawnside to noonside, in a frequency range between 10 fcp and fLHR. The zipper-like magnetosonic waves may provide a new clue to nonlinear excitation or modulation process, while its cause still remains to be fully understood.

  19. A Neural Network Approach for Identifying Relativistic Electron Pitch Angle Distributions in Van Allen Probes Data

    NASA Astrophysics Data System (ADS)

    Souza, V. M. C. E. S.; Vieira, L.; Alves, L. R.; Da Silva, L. A.; Koga, D.; Sibeck, D. G.; Walsh, B.; Kanekal, S. G.; Silveira, M. D.; Medeiros, C.; Mendes, O., Jr.; Marchezi, J.; Rockenbach, M.; Jauer, P. R.; Gonzalez, W.; Baker, D. N.

    2015-12-01

    A myriad of physical phenomena occur in the inner magnetosphere, in particular at the Earth's radiation belts, which can be a result of the combination of both internal and external processes. However, the connection between physical processes occurring deep within the magnetosphere and external interplanetary drivers it is not yet well understood. In this work we investigate whether a selected set of interplanetary structures affect the local time distribution of three different classes of high energy electron pitch angle distributions (PADs), namely normal, isotropic, and butterfly. We split this work into two parts: initially we focus on the methodology used which employs a Self-Organized Feature Map (SOFM) neural network for identifying different classes of electron PAD shapes in the Van Allen Probes' Relativistic Electron Proton Telescope (REPT) data. The algorithm can categorize the input data into an arbitrary number of classes from which three of them appears the most: normal, isotropic and butterfly. Other classes which are related with these three also emerge and deserve to be addressed in detail in future works. We also discuss the uncertainties of the algorithm. Then, we move to the second part where we describe in details the criteria used for selecting the interplanetary events, and also try to investigate the relation between key parameters characterizing such interplanetary structures and the local time distributions of electron PAD shapes.

  20. Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt

    NASA Astrophysics Data System (ADS)

    Mann, I. R.; Ozeke, L. G.; Murphy, K. R.; Claudepierre, S. G.; Turner, D. L.; Baker, D. N.; Rae, I. J.; Kale, A.; Milling, D. K.; Boyd, A. J.; Spence, H. E.; Reeves, G. D.; Singer, H. J.; Dimitrakoudis, S.; Daglis, I. A.; Honary, F.

    2016-10-01

    Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging is understanding the recently discovered ultra-relativistic third electron radiation belt. Current theory asserts that loss in the heart of the outer belt, essential to the formation of the third belt, must be controlled by high-frequency plasma wave-particle scattering into the atmosphere, via whistler mode chorus, plasmaspheric hiss, or electromagnetic ion cyclotron waves. However, this has failed to accurately reproduce the third belt. Using a data-driven, time-dependent specification of ultra-low-frequency (ULF) waves we show for the first time how the third radiation belt is established as a simple, elegant consequence of storm-time extremely fast outward ULF wave transport. High-frequency wave-particle scattering loss into the atmosphere is not needed in this case. When rapid ULF wave transport coupled to a dynamic boundary is accurately specified, the sensitive dynamics controlling the enigmatic ultra-relativistic third radiation belt are naturally explained.