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  • 1
    Electronic Resource
    Electronic Resource
    The impact of incorrectly estimating factor productivity in agriculture on the environment and human health (1999)
    Springer
    Environmental geology 37 (1999), S. 47-53 
    Details
    ISSN: 1432-0495
    Keywords: Key words Agricultural production ; Environment ; Input use ; Technological innovation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  This paper explores the implications of a misspecification of the production function on the use of factor inputs in the context of the adoption of an alternative production practice (a technological innovation) designed to mitigate the impact of agricultural production on human health and the environment. It is demonstrated that if the level of the use of some inputs is considered rather than their consumptive use (i.e., the actual amount used by a plant), the productivity of the input is inaccurately measured. It is also demonstrated that an aggregate production function approach can lead to overestimation of the value of the marginal product of an input due to the frequently implicit assumptions that the output supply, output demand, and fertilizer demand are infinitely price elastic. The implications of the results are important for determining the optimal use of inputs such as fertilizer and pesticides which have known adverse impacts on the environment and human health.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002540050359
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  • 2
    Electronic Resource
    Electronic Resource
    An efficient cost-sharing program to reduce nonpoint-source contamination: theory and an application to groundwater contamination (2000)
    Springer
    Environmental geology 39 (2000), S. 649-659 
    Details
    ISSN: 1432-0495
    Keywords: Key words Cost-share ; Irrigation ; Nitrogen fertilizer ; Nonjoint production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract This research evaluates the economics of cost-sharing improved irrigation technologies to reduce agricultural, nonpoint-source contamination. Irrigation and fertilization inefficiencies are modeled within a nonjoint production process to evaluate both private and public costs of technology adoption and its effect on groundwater nitrate-contamination levels. A central Nebraska application indicates that even without a current government subsidy, a farmer is economically better off switching from gravity-flow to surge-flow irrigation rather than a center-pivot system. An annual government subsidy of $22.50 (US$) per hectare per year is required over the life of a center-pivot system to make the farmer financially indifferent. However, cost-sharing center-pivot adoption improves the groundwater contamination level, while other irrigation systems result in continued deterioration of groundwater quality.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002540050477
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  • 3
    Electronic Resource
    Electronic Resource
    Primary malignant fibrous histiocytoma of the liver: imaging features of five surgically confirmed cases (1999)
    Springer
    Abdominal imaging 24 (1999), S. 386-391 
    Details
    ISSN: 1432-0509
    Keywords: Key words: Histiocytoma—Liver neoplasms—Liver neoplasms, CT—Liver neoplasms, diagnosis—Liver neoplasms, MR.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: The purpose of the present study was to describe the various imaging features of primary malignant fibrous histiocytoma (MFH) of the liver, a rare tumor of mesenchymal origin. Methods: Sonography (n= 5), computed tomography (CT; n= 5), magnetic resonance (MR) imaging (n= 2), and hepatic arteriography (n= 3) in five patients who underwent partial hepatectomy for tumor resection were retrospectively reviewed and correlated with pathologic findings. Results: All tumors were clearly demarcated from surrounding hepatic parenchyma in sectional imaging with (n= 2) or without (n= 3) a fibrous capsule, which was pathologically verified. Internal architecture of abundant fibrosis, myxoid degeneration, and/or hemorrhagic necrosis reflected the sonographic, CT and MR imaging findings. Marginal tumor staining without definite tumor vasculature was the main feature of hepatic arteriography. There was no intratumoral calcification. All three tumors involving the right lobe of the liver invaded the right hemidiaphragm. Conclusion: Although there were no unique findings of primary hepatic MFH, a combined interpretation of various imaging modalities may elucidate the malignant nature of the tumor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002619900520
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  • 4
    Electronic Resource
    Electronic Resource
    Endogenous technological change and pollution abatement (1996)
    Springer
    Environmental geology 27 (1996), S. 191-197 
    Details
    ISSN: 1432-0495
    Keywords: Abatement technology ; Agricultural production ; Environmental externalities ; Nonpoint source pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Nonpoint source pollution control is a more complicated process than traditional analysis suggests. Whether a new pollution abatement technology is developed exogenously or endogenously and the per unit reduction in the rate at which a pollutant associated with the use of a factor of production needed to produce an agricultural commodity due to this technology enters the environment are critical factors in the determination of the effects of agricultural production on the pollutant stock. These are the issues addressed here. The optimal current period research and development expenditures on an endogenously induced abatement technology associated with the use of a factor of production giving rise to environmental externalities are shown to be a function of, among other things, the cumulation of all research and development expenditures, the probability of an abatement technology being developed, the level of use of the factor of production, the unit pollution tax on the factor, the rate of time preference (discount rate), the rate at which the pollutant associated with the factor enters the environment, the rate of discharge of the pollutant stock, and so forth. Finally, the analysis demonstrates that a reduction in pollution by the adoption of an abatement technology may lead to an increase in the pollutant stock as a result of endogenous technological change associated with the pollution abatement. When the rate of pollution reduction is greater than a threshold, however, the adoption of an endogenously determined abatement technology will unequivocally lead to a reduction in the pollutant stock.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00770432
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  • 5
    Electronic Resource
    Electronic Resource
    Collapse of resonance in quasi-one-dimensional quantum channels (1999)
    Springer
    Journal of experimental and theoretical physics 89 (1999), S. 144-150 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study the resonance structure of the conductance (transmissivity) of a quasi-one-dimensional channel that contains an attractive impurity of finite dimensions and derive an exact expression for the scattering matrix. We show that an impurity of finite dimensions may cause a set of Fano resonances to appear in the transmissivity. We also find that due to the coherent interaction the Fano resonances can collapse and discrete levels may appear in the continuum. Finally, we establish the wave function of the discrete levels and study the channel transmissivity in the critical regime.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558969
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  • 6
    Electronic Resource
    Electronic Resource
    Tunneling through discrete levels in the continuum (1999)
    Springer
    Journal of experimental and theoretical physics 88 (1999), S. 118-127 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We study the ballistic transport in quantum channels containing attractive impurities. We show that coherent interaction between asymptotic resonances may cause resonances to disappear and discrete levels to appear in the continuum at certain (critical) values of the parameters of the system. For the first time the tunneling of an electron through discrete levels is investigated. We find that the transmissivity changes dramatically when the scattered electrons at infinity have an energy coinciding with that of the discrete levels. It is found that a new type of degeneracy may arise in the system at critical values of the parameters, a degeneracy in which one state is described by a localized wave function and the other, by a propagating wave function. We calculate the critical values of the parameters of the structure and discuss ways of experimentally implementing this effect in two-dimensional channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.558773
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  • 7
    Electronic Resource
    Electronic Resource
    Fano resonances and electron localization in heterobarriers (2000)
    Springer
    Journal of experimental and theoretical physics 91 (2000), S. 361-368 
    Details
    ISSN: 1090-6509
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A study is made of electron tunneling in semiconductor heterostructures having a complex dispersion law. A generalized Fabry-Perot approach is used to describe tunneling across the barrier. Mixing of electron states at the heterojunctions is responsible for the asymmetric resonant structure of the transmission which is characterized by a resonance-antiresonance pair. The resonance corresponds to a pole while the antiresonance corresponds to a zero of the scattering amplitude in the complex energy plane, i.e., near the pole and the zero the transmission of the heterobarrier has a Fano resonance structure. It is shown that for certain barrier parameters the resonances may collapse and localized states may appear in the heterobarrier, which is observed on the current-voltage characteristics of the barriers. The two-valley model of a GaAs/AlxGa1−x As/GaAs heterostructure is considered as an example. An analysis is made of the resonance structure in the barrier as a function of the type of boundary conditions used for the heterojunctions. The low-temperature current-voltage characteristic of the barrier is calculated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.1311996
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  • 8
    Electronic Resource
    Electronic Resource
    Changes in Starch Pasting Properties Due to Sugars and Emulsifiers as Determined by Viscosity Measurement (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 57 (1992), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of sugars, emulsifiers, and their interactions on starch pasting properties were determined by the Rapid Visco-Analyser (RVA). Solutions of 50% sugars in water were used. The disaccharides, sucrose and lactose, delayed pasting more than did the monosaccharide, dextrose. Sugars’effects on starch pasting delay and on starch paste consistency varied with the starch. Addition of the same emulsifier (1%) to different starches did not result in the same change in paste consistency in the presence of high amounts of sugar. Both sucrose ester F-160 (SE) and polysorbate 60 (PS) reduced the hot paste consistency of starch-sugar mixtures, with SE having a greater effect than PS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1992.tb14344.x
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  • 9
    Electronic Resource
    Electronic Resource
    Enzymatic trimethylation of residue-72 lysine in cytochrome c. Effect on the total structure
    Amsterdam : Elsevier
    BBA - Protein Structure 622 (1980), S. 144-150 
    Details
    ISSN: 0005-2795
    Keywords: (N. crassa, S. cerevisiae) ; Cytochrome c methylation ; Isoelectric focusing ; Protein methylase ; Space-filling model
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2795(80)90166-X
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of growth interruption on the optical and the structural properties of InGaN/GaN quantum wells grown by metalorganic chemical vapor deposition (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 5642-5646 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Effects of growth interruption on the optical and the structural properties of InGaN/GaN quantum wells were investigated by using photoluminescence, transmission electron microscopy, optical microscopy, and high resolution x-ray diffraction. The InxGa1−xN/GaN (x〉0.2) quantum wells used in this study were grown on c-plane sapphire by using metalorganic chemical vapor deposition. The interruption was carried out by closing the group-III metalorganic sources before and after the growths of the InGaN quantum well layers. The transmission electron microscopy images show that with increasing interruption time, the quantum-dot-like regions and well thickness decreased due to indium reevaporation or the thermal etching effect. As a result the photoluminescence peak position was blueshifted and the intensity was reduced. Temperature- and excitation-power-dependent photoluminescence spectra support the results of transmission electron microscopy measurements. The sizes and the number of V defects did not differ with the interruption time. The interruption time is not directly related to the formation of defects. The V defect originates at threading dislocations and inversion domain boundaries due to higher misfit strain. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1410320
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