ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Neutron Scattering from a Solution of a Polymer in a Polymer. The Effect of Long-Range Heterogeneities (1978)

Summerfield, George C. ; King, John S. ; Ullman, Robert

s.l. : American Chemical Society

Macromolecules 11 (1978), S. 218-220

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ISSN: 1520-5835

Source: ACS Legacy Archives

Topics: Chemistry and Pharmacology , Physics

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1021/ma60061a040

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2

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Small-angle neutron scattering on bulk polystyrene with mismatched Mw (1982)

Tangari, C. ; King, John S. ; Summerfield, G. C.

s.l. : American Chemical Society

Macromolecules 15 (1982), S. 132-136

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ISSN: 1520-5835

Source: ACS Legacy Archives

Topics: Chemistry and Pharmacology , Physics

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1021/ma00229a027

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3

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Reduction of soil carbon formation by tropospheric ozone under increased carbon dioxide levels (2003)

Pregitzer, Kurt S. ; Karberg, Noah J. ; King, John S. ; [et al.]

[s.l.] : Macmillian Magazines Ltd.

Nature 425 (2003), S. 705-707

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ISSN: 1476-4687

Source: Nature Archives 1869 - 2009

Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics

Notes: [Auszug] In the Northern Hemisphere, ozone levels in the troposphere have increased by 35 per cent over the past century, with detrimental impacts on forest and agricultural productivity, even when forest productivity has been stimulated by increased carbon dioxide levels. In addition to reducing ...

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1038/nature02047

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4

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A multiyear synthesis of soil respiration responses to elevated atmospheric CO2 from four forest FACE experiments (2004)

King, John S. ; Hanson, Paul J. ; Bernhardt, Emily ; [et al.]

Oxford, UK : Blackwell Science Ltd

Global change biology 10 (2004), S. 0

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ISSN: 1365-2486

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography

Notes: The rapidly rising concentration of atmospheric CO2 has the potential to alter forest and global carbon cycles by altering important processes that occur in soil. Forest soils contain the largest and longest lived carbon pools in terrestrial ecosystems and are therefore extremely important to the land–atmosphere exchange of carbon and future climate. Soil respiration is a sensitive integrator of many soil processes that control carbon storage in soil, and is therefore a good metric of changes to soil carbon cycling. Here, we summarize soil respiration data from four forest free-air carbon dioxide enrichment (FACE) experiments in developing and established forests that have been exposed to elevated atmospheric [CO2] (168 μL L−1 average enrichment) for 2–6 years. The sites have similar experimental design and use similar methodology (closed-path infrared gas analyzers) to measure soil respiration, but differ in species composition of the respective forest communities. We found that elevated atmospheric [CO2] stimulated soil respiration at all sites, and this response persisted for up to 6 years. Young developing stands experienced greater stimulation than did more established stands, increasing 39% and 16%, respectively, averaged over all years and communities. Further, at sites that had more than one community, we found that species composition of the dominant trees was a major controller of the absolute soil CO2 efflux and the degree of stimulation from CO2 enrichment. Interestingly, we found that the temperature sensitivity of bulk soil respiration appeared to be unaffected by elevated atmospheric CO2. These findings suggest that stage of stand development and species composition should be explicitly accounted for when extrapolating results from elevated CO2 experiments or modeling forest and global carbon cycles.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1529-8817.2003.00789.x

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5

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Soil nitrogen transformations under Populus tremuloides, Betula papyrifera and Acer saccharum following 3 years exposure to elevated CO2 and O3 (2003)

Holmes, William E. ; Zak, Donald R. ; Pregitzer, Kurt S. ; [et al.]

Oxford, UK : Blackwell Science Ltd

Global change biology 9 (2003), S. 0

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ISSN: 1365-2486

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography

Notes: Increases in atmospheric CO2 and tropospheric O3 may affect forest N cycling by altering plant litter production and the availability of substrates for microbial metabolism. Three years following the establishment of our free-air CO2–O3 enrichment experiment, plant growth has been stimulated by elevated CO2 resulting in greater substrate input to soil; elevated O3 has counteracted this effect. We hypothesized that rates of soil N cycling would be enhanced by greater plant productivity under elevated CO2, and that CO2 effects would be dampened by O3. We found that elevated CO2 did not alter gross N transformation rates. Elevated O3 significantly reduced gross N mineralization and microbial biomass N, and effects were consistent among species. We also observed significant interactions between CO2 and O3: (i) gross N mineralization was greater under elevated CO2 (1.0 mg N kg−1 day−1) than in the presence of both CO2 and O3 (0.5 mg N kg−1 day−1) and (ii) gross NH4+ immobilization was also greater under elevated CO2 (0.8 mg N kg−1 day−1) than under CO2 plus O3 (0.4 mg N kg−1 day−1). We used a laboratory 15N tracer method to quantify transfer of inorganic N to organic pools. Elevated CO2 led to greater recovery of NH4+-15N in microbial biomass and corresponding lower recovery in the extractable NO3− pool. Elevated CO2 resulted in a substantial increase in NO3−-15N recovery in soil organic matter. We observed no O3 main effect and no CO2 by O3 interaction effect on 15N recovery in any soil pool. All of the above responses were most pronounced beneath Betula papyrifera and Populus tremuloides, which have grown more rapidly than Acer saccharum. Although elevated CO2 has increased plant productivity, the resulting increase in plant litter production has yet to overcome the influence of the pre-existing pool of soil organic matter on soil microbial activity and rates of N cycling. Ozone reduces plant litter inputs and also appears to affect the composition of plant litter in a way that reduces microbial biomass and activity.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1365-2486.2003.00705.x

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6

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Chemistry and decomposition of litter from Populus tremuloides Michaux grown at elevated atmospheric CO2 and varying N availability (2001)

King, John S. ; Pregitzer, Kurt S. ; Zak, Donald R. ; [et al.]

Oxford, UK : Blackwell Science Ltd

Global change biology 7 (2001), S. 0

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ISSN: 1365-2486

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography

Notes: It has been hypothesized that greater production of total nonstructural carbohydrates (TNC) in foliage grown under elevated atmospheric carbon dioxide (CO2) will result in higher concentrations of defensive compounds in tree leaf litter, possibly leading to reduced rates of decomposition and nutrient cycling in forest ecosystems of the future. To evaluate the effects of elevated atmospheric CO2 on litter chemistry and decomposition, we performed a 111 day laboratory incubation with leaf litter of trembling aspen (Populus tremuloides Michaux) produced at 36 Pa and 56 Pa CO2 and two levels of soil nitrogen (N) availability. Decomposition was quantified as microbially respired CO2 and dissolved organic carbon (DOC) in soil solution, and concentrations of nonstructural carbohydrates, N, carbon (C), and condensed tannins were monitored throughout the incubation. Growth under elevated atmospheric CO2 did not significantly affect initial litter concentrations of TNC, N, or condensed tannins. Rates of decomposition, measured as both microbially respired CO2 and DOC did not differ between litter produced under ambient and elevated CO2. Total C lost from the samples was 38 mg g−1 litter as respired CO2 and 138 mg g−1 litter as DOC, suggesting short-term pulses of dissolved C in soil solution are important components of the terrestrial C cycle. We conclude that litter chemistry and decomposition in trembling aspen are minimally affected by growth under higher concentrations of CO2.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1365-2486.2001.00388.x

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7

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Nuclear fusion from crack-generated particle acceleration (1990)

Mayer, Frederick J. ; King, John S. ; Reitz, John R.

Springer

Journal of fusion energy 9 (1990), S. 269-272

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ISSN: 1572-9591

Source: Springer Online Journal Archives 1860-2000

Topics: Energy, Environment Protection, Nuclear Power Engineering

Notes: Summary In summary, the high-voltages necessary to accelerate deuterons to energies sufficient to produce modest numbers (104–105/sec) of d-d neutrons appears to be possible as a result of cracking or “fracture” of the metal lattice in the “cold” fusion experiments. This mechanism requires neither “massive” electrons nor “exotic” nuclear reactions to explain the apparent “cold” fusion d-d neutron production results. Instead, it is possible that high voltage electrostatic fields, known to be associated with cracking, can reside across a crack gap long enough for the deuterons to be accelerated to sufficiently high energy to produce the d-d reactions. Interestingly, the electrostatic acceleration is quite similar to that of laboratory accelerators except for its submicron scale. Clearly, much work is still required to determine whether such a crack-generated acceleration mechanism, a “quasi-particle” mechanism, some combination of these, or some other, as yet unidentified mechanism is responsible for the nuclear effects seen in “cold” fusion experiments.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01059241

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8

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Clonal variation in above- and below-ground growth responses of Populus tremuloides Michaux: Influence of soil warming and nutrient availability (1999)

King, John S. ; Pregitzer, Kurt S. ; Zak, Donald R.

Springer

Plant and soil 217 (1999), S. 119-130

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ISSN: 1573-5036

Keywords: biomass partitioning ; clonal variation ; N-availability ; Populus tremuloides ; root longevity ; soil warming

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Trembling aspen (Populus tremuloides Michx.) is the most widely distributed tree species in North America making it important to terrestrial carbon and nutrient cycles. Due to anthropogenic climate change high latitude temperatures are expected to increase, making it necessary to assess the feedback between above- and below-ground carbon pools to increased temperature at sites of both high and low N-availability. We grew four clones of aspen at two levels of soil temperature and two levels of soil N-availability for 98 days and quantified photosynthesis, growth, biomass allocation, and root length production and mortality. High soil temperature increased rates of photosynthesis (65%), resulting in greater whole-plant growth (37%) through increases in roots, stems, and foliage; however these increases generally occurred only in soil of high N-availability. Root:shoot biomass allocation varied between clones but was unaffected by the soil temperature or N-availability treatments. Root length production and mortality increased at elevated soil temperature, but this response was modified by soil N-availability. At high soil temperature, soil N-availability had little effect on root dynamics, while at low soil temperature, high soil N-availability increased both the production and mortality (turnover) of roots. We conclude that trembling aspen has the potential for substantially greater growth and root turnover under conditions of warmer soil at sites of both high and low N-availability, but that allometric patterns of growth are under strong genetic, rather than environmental control.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1004560311563

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9

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Investigation of heterogeneities in solid polyethylene by small angle neutron scatteringSupported in part by the National Science Foundation under Grant No. DMR 76-80152. (1977)

Ullman, Robert ; Summerfield, George C. ; King, John S.

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Physics Edition 15 (1977), S. 1641-1646

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ISSN: 0098-1273

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Notes: Small angle neutron scattering was applied to the investigation of heterogeneities in solid poly-ethylene. The heterogeneities arise from the contrast between amorphous and crystalline regions and also from the presence of a small fraction of voids. The method is easily put on an absolute basis by calibration with an incoherent scatterer, in this case, cyclohexane.

Additional Material: 1 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pol.1977.180150911

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