Search Results - (Author, Cooperation:M. Krol)

Showing 1 - 20 results of 27, query time: 0.32s Refine Results
  1. 1
    Staff View
    Publication Date:
    2012-09-01
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Atmosphere/*chemistry ; Carbon Dioxide/*analysis ; *Climate Change
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    S. A. Montzka ; M. Krol ; E. Dlugokencky ; B. Hall ; P. Jockel ; J. Lelieveld
    American Association for the Advancement of Science (AAAS)
    Published 2011
    Staff View
    Publication Date:
    2011-01-08
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Staff View
    Publication Date:
    2018-02-03
    Publisher:
    Wiley-Blackwell
    Print ISSN:
    0072-1050
    Electronic ISSN:
    1099-1034
    Topics:
    Geosciences
    Published by:
    http://www.wiley.com/wiley-blackwell

    Latest Papers from Table of Contents or Articles in Press
  4. 4
    Hsu, C. C. ; McGinnis, B. P. ; Sokoloff, J. P. ; Khitrova, G. ; Gibbs, H. M. ; Peyghambarian, N. ; Johns, S. T. ; Krol, M. F.

    [S.l.] : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The room-temperature nonlinear absorption spectra of a 40 A(ring) GaInAs/AlInAs and a 90 A(ring) GaAlInAs/AlInAs multiple quantum well (MQW) were measured near 1.3 μm using a pump and probe technique. Saturation carrier densities at the heavy-hole exciton peak were determined to be 1.2×1018 and 1.0×1018 cm−3 with carrier recovery times of (approximately-equal-to)5 ns and (approximately-equal-to)750 ps for the two samples, respectively. These measured saturation carrier densities are close to the reported values for GaAs/AlGaAs MQWs. Fabry–Perot etalons with integrated mirrors grown by molecular beam epitaxy with GaInAs/AlInAs MQWs as spacer layers were also fabricated as optical logic gate devices. We demonstrate a 125-ps recovery time for the etalon switching device at room temperature.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.350175

    Articles: DFG German National Licenses
  5. 5
    Ten, S. ; Krol, M. F. ; McGinnis, B. P. ; Hayduk, M. J. ; Khitrova, G. ; Peyghambarian, N.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We present a detailed investigation of electron tunneling in (Ga,In)As/(Al,In)As asymmetric double quantum wells as a function of different excitation and temperature conditions. We show that tunneling dynamics depend strongly on the initial carrier temperature and momentum. For example, electron and hole tunneling out of the narrow well is complete at low temperature. However at room temperature carriers do not exhibit any tunneling kinetics. We propose a simple kinetic model which describes the observed population dynamics at different carrier densities, temperatures, and excitation conditions. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.360995

    Articles: DFG German National Licenses
  6. 6
    Ten, S. ; Krol, M. F. ; Guerreiro, P. T. ; Peyghambarian, N.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We present unambiguous experimental evidence for the dramatic dependence of hole tunneling rates on in-plane momentum in (Ga,In)As/(Al,In)As asymmetric double quantum wells. Holes generated near the band edge tunnel on hundred picosecond time scales, whereas holes excited with large excess energy tunnel on subpicosecond time scales. The mechanism responsible for this increase of more than three orders of magnitude in the hole tunneling rate is nonresonant delocalization of hole wave functions by band mixing in the valence band. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.117268

    Articles: DFG German National Licenses
  7. 7
    Krol, M. F. ; Leavitt, R. P. ; Pham, J. T. ; McGinnis, B. P. ; Peyghambarian, N.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We report enhanced electroabsorption in selectively doped (Ga,In)As/(Al,In)As asymmetric double quantum wells (ADQWs) by the use of real space electron transfer. The electron concentration in both the wide and narrow wells is investigated by field dependent absorption and photoluminescence spectroscopy. The results are compared to absorption changes in an undoped ADQW structure that utilizes the quantum confined stark effect. The doped modulator exhibits a significantly larger red shift with applied field than the undoped structure. © 1995 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.114272

    Articles: DFG German National Licenses
  8. 8
    Krol, M. F. ; Ohtsuki, T. ; Khitrova, G. ; Boncek, R. K. ; McGinnis, B. P. ; Gibbs, H. M. ; Peyghambarian, N.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1993
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A high contrast, low intensity GaAlInAs/AlInAs multiple quantum well asymmetric Fabry–Perot reflection modulator for operation at 1.3 μm has been demonstrated. The reflection modulator takes advantage of the large absorptive and refractive nonlinearities associated with saturating the heavy-hole exciton resonance. We achieve an on/off contrast ratio in excess of 1000:1 (30 dB) and an insertion loss of 2.2 dB at a pump intensity of 30 kW/cm2, corresponding to a carrier density of 4.5×1017 cm−3. The modulator was demonstrated to have a large operating bandwidth, achieving an on/off contrast ratio of greater than 100:1 over a 5 nm optical band. The operating speed of the modulator was measured and found to approach 1 GHz.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.108637

    Articles: DFG German National Licenses
  9. 9
    Savitch, L. V. ; Leonardos, E. D. ; Krol, M. ; Jansson, S. ; Grodzinski, B. ; Huner, N. P. A. ; Öquist, G.

    Oxford, UK : Blackwell Science, Ltd
    Published 2002
    Staff View
    ISSN:
    1365-3040
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Biology
    Notes:
    Seedlings of Lodgepole pine (Pinus contorta L.) and winter wheat (Triticum aestivum L. cv. Monopol) were cold acclimated under controlled conditions to induce frost hardiness. Lodgepole pine responded to cold acclimation by partial inhibition of photosynthesis with an associated partial loss of photosystem II reaction centres, and a reduction in needle chlorophyll content. This was accompanied by a low daily carbon gain, and the development of a high and sustained capacity for non-photochemical quenching of absorbed light. This sustained dissipation of absorbed light as heat correlated with an increased de-epoxidation of the xanthophyll cycle pigments forming the quenching forms antheraxanthin and zeaxanthin. In addition, the PsbS protein known to bind chlorophyll and the xanthophyll cycle pigments increased strongly during cold acclimation of pine. In contrast, winter wheat maintained high photosynthetic rates, showed no loss of chlorophyll content per leaf area, and exhibited a high daily carbon gain and a minimal non-photochemical quenching after cold acclimation. In accordance, cold acclimation of wheat neither increased the de-epoxidation of the xanthophylls nor the content of the PsbS protein. These different responses of photosynthesis to cold acclimation are correlated with pine, reducing its need for assimilates when entering dormancy associated with termination of primary growth, whereas winter wheat maintains a high need for assimilates as it continues to grow and develop throughout the cold-acclimation period. It appears that without evolving a sustained ability for controlled dissipation of absorbed light as heat throughout the winter, winter green conifers would not have managed to adapt and establish themselves so successfully in the cold climatic zones of the northern hemisphere.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1046/j.1365-3040.2002.00861.x

    Articles: DFG German National Licenses
  10. 10
    Klukowska, A. ; Czyrny, Z. ; Laguna, P. ; Brzewski, M. ; Serafin-Krol, M. A. ; Rokicka-Milewska, R.

    Oxford UK : Blackwell Science Ltd
    Published 2001
    Staff View
    ISSN:
    1365-2516
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Medicine
    Notes:
    The aims of the study were to evaluate the clinical, radiological and ultrasonographical images of knee joints in children with severe haemophilia and von Willebrand’s disease, to determine the correlation between these images and to assess the usefulness of ultrasonography (USG) in evaluating the intensity of haemophilic arthropathy. Thirty-nine boys were included in the study, all of them with a past history of knee bleeds. The average age of the children was 10.02 ± 3.01 years. In patients with slight (1–3 points) and moderate (4–7 points) radiological changes in knee joint bones, an increase in synovial fluid, considerable hypertrophy and inflammation of the synovium were observed in USG. In haemophilic patients with severe (8–13 points) bone changes, the amount of fluid was usually normal and there was slight inflammation but considerable hypertrophy of the synovium. Radiological evaluation of haemophilic arthropathy was made according to the Pettersson classification. A good correlation between the degree of cartilage damage in USG and the progression of bone changes in radiographs was found. Cartilage and bone damage progressed with the increase in the number of intra-articular haemorrhages into the knee joint. In our opinion USG is useful in evaluating the fluid, synovium and cartilage of joints in haemophiliacs.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1046/j.1365-2516.2001.00509.x

    Articles: DFG German National Licenses
  11. 11
    Staff View
    ISSN:
    1476-4687
    Source:
    Nature Archives 1869 - 2009
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Notes:
    [Auszug] The consumption of methyl chloroform (1,1,1-trichloroethane), an industrial solvent, has been banned by the 1987 Montreal Protocol because of its ozone-depleting potential. During the 1990s, global emissions have decreased substantially and, since 1999, near-zero emissions have been estimated for ...
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1038/nature01311

    Articles: DFG German National Licenses
  12. 12
    Staff View
    ISSN:
    0891-5849
    Keywords:
    Ambroxol ; Antioxidant ; Deoxyribose oxidation ; Free radicals ; Lipid peroxidation ; Monochlorodimedon chlorination
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0891-5849(94)90130-9

    Articles: DFG German National Licenses
  13. 13
    Staff View
    ISSN:
    0302-4598
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0302-4598(92)85012-5

    Articles: DFG German National Licenses
  14. 14
    Staff View
    ISSN:
    0022-0728
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0022-0728(92)85037-4

    Articles: DFG German National Licenses
  15. 15
    Huner, N. P. A. ; Maxwell, D. P. ; Gray, G. R. ; Savitch, L. V. ; Krol, M. ; Ivanov, A. G. ; Falk, S.

    Copenhagen : Munksgaard International Publishers
    Published 1996
    Staff View
    ISSN:
    1399-3054
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Biology
    Notes:
    A basic requirement of all photosynthetic organisms is a balance between overall energy supply through temperature-independent photochemical reactions and energy consumption through the temperature-dependent biochemical reactions of photosynthetic electron transport and contiguous metabolic pathways. Since the turnover of photosystem II (PSII) reaction centers is a limiting step in the conversion of light energy into ATP and NADPH, any energy imbalance may be sensed through modulation of the redox state of PSII. This can be estimated in vivo by chlorophyll a fluorescence as changes in the redox state of PSII, or photosystem II excitation pressure, which reflects changes in the redox poise of intersystem electron transport carriers. Through comparisons of photosynthetic adjustment, we show that growth at low temperature mimics growth at high light. We conclude that terrestrial plants, green algae and cyanobacteria do not respond to changes in growth temperature or growth irradiance per se, but rather, respond to changes in the redox state of intersystem electron transport as reflected by changes in PSII excitation pressure, We suggest that this chloroplastic redox sensing mechanism may be an important component for sensing abiotic stresses in general. Thus, in addition to its role in energy transduction, the chloroplast may also be considered a primary sensor of environmental change through a redox sensing/signalling mechanism that acts synergistically with other signal transduction pathways to elicit the appropriate molecular and physiological responses.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1034/j.1399-3054.1996.980218.x

    Articles: DFG German National Licenses
  16. 16
    Alcamo, J. ; Krol, M. ; Posch, M.
    Springer
    Published 1995
    Staff View
    ISSN:
    1573-2932
    Keywords:
    acidification ; air pollution impacts ; climate change ; global change ; integrated modeling ; sulfur deposition
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Energy, Environment Protection, Nuclear Power Engineering
    Notes:
    Abstract This paper presents one of the first integrated analyses of acidification and climate change on a geographically-detailed basis, and the first linkage of integrated models for acid deposition (RAINS) and for climate change (IMAGE 2). Emphasis in this paper is on Europe. Trends in driving forces of emissions are used to compute anthropogenic SO2 emissions in 13 world regions. These emissions are translated into regional patterns of sulfur deposition in Europe and global patterns of sulfate aerosols using source-receptor matrices. Changes in climate are then computed based on changes in sulfate and greenhouse gases. Finally, we compute ecosystem areas affected by acid deposition and climate change based on exceedances of critical loads and changes in potential vegetation. Using this framework, information from global and regional integrated models can be used to link sulfur emissions with both their global and regional consequences. Preliminary calculations indicate that the size of European area affected by climate change in 2100 (58%) will be about the same as that affected by acid deposition in 1990. By the mid 21st century, about 14% of Europe's area may be affected by both acid deposition and climate change. Also, reducing sulfur emissions in Europe will have both the desirable impact of reducing the area affected by acid deposition, and the undesirable impact of enhancing climate warming in Europe and thus increasing the area affected by climate change. However, for the scenarios in this paper, the desirable impact of reducing sulfur emissions greatly outweighs its undesirable impact.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00477200

    Articles: DFG German National Licenses
  17. 17
    Staff View
    ISSN:
    1573-2932
    Keywords:
    climate model ; atmospheric chemistry ; oceanic C cycle ; scenario evaluation ; integrated model
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Energy, Environment Protection, Nuclear Power Engineering
    Notes:
    Abstract This paper describes the atmosphere-ocean system of the integrated model IMAGE 2.0. The system consists of four linked models, for atmospheric composition, atmospheric climate, ocean climate and for ocean biosphere and chemistry. The first model is globally averaged, the latter are zonally averaged with additional resolution in the vertical. The models reflect a compromise between describing the physical, chemical and biological processes and moderate computational requirements. The system is validated with direct observations for current conditions (climate, chemistry) and is consistent with results from General Circulation Model experiments. The system is used in the integrated setting of the IMAGE 2.0 model to give transient climate projections. Global surface temperature is simulated to increase by 2.5 K over the next century for socio-economic scenarios with continuing economic and population growth. In a scenario study with reduced ocean circulation, the climate system and the global C cycle are found to be appreciably sensitive to such changes.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00478343

    Articles: DFG German National Licenses
  18. 18
    Alcamo, J. ; Kreileman, G. J. J. ; Krol, M. S. ; Zuidema, G.
    Springer
    Published 1994
    Staff View
    ISSN:
    1573-2932
    Keywords:
    integrated modeling ; integrated assessment ; greenhouse gas emissions ; global change ; climate change ; land cover change ; C cycle
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Energy, Environment Protection, Nuclear Power Engineering
    Notes:
    Abstract This paper describes the IMAGE 2.0 model, a multi-disciplinary, integrated model designed to simulate the dynamics of the global society-biosphere-climate system. The objectives of the model are to investigate linkages and feedbacks in the system, and to evaluate consequences of climate policies. Dynamic calculations are performed to year 2100, with a spatial scale ranging from grid (0.5°×0.5° latitudelongitude) to world regional level, depending on the sub-model. The model consists of three fully linked sub-systems: Energy-Industry, Terrestrial Environment, and Atmosphere-Ocean. The Energy-Industry models compute the emissions of greenhouse gases in 13 world regions as a function of energy consumption and industrial production. End use energy consumption is computed from various economic/demographic driving forces. The Terrestrial Environment models simulate the changes in global land cover on a gridscale based on climatic and economic factors, and the flux of CO2 and other greenhouse gases from the biosphere to the atmosphere. The Atmosphere-Ocean models compute the buildup of greenhouse gases in the atmosphere and the resulting zonal-average temperature and precipitation patterns. The fully linked model has been tested against data from 1970 to 1990, and after calibration can reproduce the following observed trends: regional energy consumption and energy-related emissions, terrestrial flux of CO2 and emissions of greenhouse gases, concentrations of greenhouse gases in the atmosphere, and transformation of land cover. The model can also simulate long term zonal average surface and vertical temperatures.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00478335

    Articles: DFG German National Licenses
  19. 19
    Krol, M. S. ; Woerd, H. J.
    Springer
    Published 1994
    Staff View
    ISSN:
    1573-2932
    Keywords:
    atmospheric chemistry ; CH4 ; OH ; O3 ; emissions scenarios ; integrated modeling
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Energy, Environment Protection, Nuclear Power Engineering
    Notes:
    Abstract The future radiative forcing by non-CO2 greenhouse gases depends strongly on the behavior of the OH radical, which represents the primary sink for CH4, CO and H(C)FCs in the atmosphere. We present a simple model to describe the changes in the concentration of the main greenhouse gases. The focus is on the description of the atmospheric chemistry of OH and the important tropospheric oxidant and greenhouse gas O3. Changes in the equilibrium concentrations of these oxidants will change the trends in the concentrations of greenhouse gases, especially CH4. The model is applied to the 1992 IPCC emissions scenarios, as well as to an IMAGE 2.0 scenario, based on “Conventional Wisdom” assumptions. We find the following major results: for the central estimate of emissions assuming no additional policies (IS92a), the concentration of CH4 keeps rising at rates similar to those observed over the last decades; results for the other IS92 scenarios range from stabilization early in the next century (IS92d) to an ever increasing rate of accumulation of CH4 in the atmosphere (IS92f), even though these scenarios assume no policy interventions. The IMAGE 2.0 Conventional Wisdom scenario is similar to IS92a before the year 2025; afterwards the expansion of agricultural area significantly decreases the emissions of hydrocarbons and NOX from savanna burning, not represented in the IS92 scenarios. This leads to stable levels of atmospheric CH4 after 2025.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00478342

    Articles: DFG German National Licenses
  20. 20
    Krol', M. D.
    Springer
    Published 1976
    Staff View
    ISSN:
    1573-8876
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Mathematics
    Notes:
    Abstract In the paper we prove the falsity of the complete Brouwer principle in a topological model of intuitionistic analysis, constructed by Moschovakis. We present a counterexample showing the impossibility of extending this model and Scott's model up to a model of intuitionistic analysis with the complete Brouwer principle.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01149927

    Articles: DFG German National Licenses