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  • 1
    Electronic Resource
    Electronic Resource
    The propagation of a single shear crack: A displacement discontinuity model (1994)
    Springer
    Pure and applied geophysics 142 (1994), S. 567-585 
    Details
    ISSN: 1420-9136
    Keywords: Crack propagation ; fracture propagation ; boundary element method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Numerical studies using the displacement discontinuity method show that a single shear crack under compression propagates in its own direction, because such propagation results in the maximum release of strain energy. The methods of linear elastic fracture mechanics may not be used for such a closed crack, and the stress intensity factors are meaningless in that case. Laboratory observations of propagation by means of “kinks” at an angle of approximately 70° to the crack may be due to heterogeneities, to the effect of a preexisting crack, to end effects, to microcracking, or to some combination of these factors. Such kinks may thus be local phenomena which cannot release most of the strain energy, and are not incompatible with our numerical results which are based on a global energy balance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00876055
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  • 2
    Electronic Resource
    Electronic Resource
    Adaptive response to mutagenesis and its molecular basis in a human T-cell leukemia line primed with a low dose ofγ-rays (1994)
    Springer
    Radiation and environmental biophysics 33 (1994), S. 211-217 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The effect was studied of a low dose ofγ-ray preexposure on the frequency and molecular spectrum of radiation-induced mutations at the hprt locus in a human T-cell leukemia line. When the cells were preexposed to 0.01 Gy ofγ-rays, the yield of mutations induced by a subsequent 2-Gy challenge dose was reduced by 60%, compared with the 2 Gy of irradiation alone. The data of Southern blot analysis showed that 47% of the mutants induced by 2 Gy in the cells without low-dose preexposure were of the deletion or rearranged mutations type. In contrast, in the low-dose radioadapted cells the proportion of this type of 2-Gy-induced mutations decreased to 28%. This is close to the control level (22%) of spontaneous mutations. Our results confirm that a low dose ofγ-ray preexposure leads to a decreased susceptibility to gene deletions and rearrangements after high-dose irradiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01212677
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  • 3
    Electronic Resource
    Electronic Resource
    Radioresistant cell strain of human fibrosarcoma cells obtained after long-term exposure to x-rays (1998)
    Springer
    Radiation and environmental biophysics 37 (1998), S. 133-137 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract A radioresistant cell strain from human fibrosarcoma HT1080 has been obtained after prolonged exposure to x-rays for 7 months (2 Gy per day, 5 days per week). This new strain, HT1080R, differs from HT1080 in a significantly increased ability of clonogenical survival, with coefficient α decreasing from 0.161 to 0.123 Gy–1 and coefficient β decreasing from 0.0950 to 0.0565 Gy–2. Furthermore, the radioresistance of HT1080R proved to be stable in long-term passaged cultures as well as in frozen samples. Differences between the two cell lines are also observed in the G-banded karyotype; the new cell line shows monosomy of chromosome 17 and loss of 5p+ and 11q+ present in the parental cells. These data suggest that the radioresistance may have been caused by radiation-induced cell mutation and that the resistant cells may have been selected by repeated irradiations. In order to characterize this new strain, the ability of the cells to rejoin DNA double-strand breaks, the cell cycle distribution and the amount of apoptosis after irradiation have been estimated; however, no differences are observed between these two cell strains. Although the mechanism of the elevated radioresistance remains unknown, this pair of cell strains can provide a new model system for further investigations with regard to the mechanisms of cellular radioresistance. The results also show that any type of irradiation similar to the schedules used in radiotherapy can lead to the formation and selection of more radioresistant cell clones in vitro, a phenomenon with possible implications for radiotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004110050106
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  • 4
    Electronic Resource
    Electronic Resource
    Monte Carlo simulation of single-cell irradiation by an electron microbeam (2000)
    Springer
    Radiation and environmental biophysics 39 (2000), S. 173-177 
    Details
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract  A model is presented for irradiation of a cellular monolayer by an electron microbeam. Results are presented for two possible window designs, cells plated on the vacuum-isolation window and cells plated on Mylar above the vacuum-isolation window. Even for the thicker dual-membrane window that facilitates tissue culture and allows the target cell to be centered relative to the electron beam, the majority of the calculated beam spreading was contained in a volume typical of the mammalian HeLa cell line. None of the 104 electrons simulated at 25 keV were scattered into the spatial region occupied by neighbors of the target cell. Dose leakage was largest at 50 keV where the mean energy deposited in all neighbors was 21% of that deposited in the target cell. This ratio was reduced to 5% at 90 keV, the highest beam energy simulated. Lineal energy spectra of energy deposition events scored in the nucleus of the target cell became progressively more like the gamma-ray spectrum as the electron beam energy increased. Hence, our simulations provide strong support for the feasibility of a low-LET, single-cell irradiator.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004110000057
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  • 5
    Electronic Resource
    Electronic Resource
    Thermal transitions of montmorillonite/polyurethane nanocomposites (2000)
    Springer
    Journal of polymer research 7 (2000), S. 245-250 
    Details
    ISSN: 1572-8935
    Keywords: Montmorillonite ; Nanocomposites ; Polyurethane ; Thermal transitions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The hard-segment phase thermal transitions and heat-resistance of benzidine-modified-montmorillonite (BZD-Mont)/polyurethane nanocomposites of different hard segment contents were found to be affected by a small amount of BZD-Mont. In particular, the presence of less than 5 wt% layered silicates from BZD-Mont can result in hard segments not only having a more thermally stable long-range order and a higher melting temperature, but also showing a loss of crystallinity of the hard segment in polyurethane. Additionally, the degradation temperature of BZD-Mont/polyurethane nanocomposite was slightly higher than that of pure polyurethane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0126-8
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  • 6
    Electronic Resource
    Electronic Resource
    Binomial option pricing with stochastic parameters: A beta distribution approach (1991)
    Springer
    Review of quantitative finance and accounting 1 (1991), S. 435-448 
    Details
    ISSN: 1573-7179
    Keywords: binomial option pricing ; stochastic parameters ; beta distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract This research extends the binomial option-pricing model of Cox, Ross, and Rubinstein (1979) and Rendleman and Barter (1979) to the case where the up and down percentage changes of stock prices are stochastic. Assuming stochastic parameters in the discrete-time binomial option pricing is analogous to assuming stochastic volatility in the continuous-time option pricing. By assuming that the up and down parameters are independent random variables following beta distributions, we are able to derive a closed-form solution to this stochastic discrete-time option pricing. We also derive an upper and a lower bounds of the option price.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408402
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  • 7
    Electronic Resource
    Electronic Resource
    Incomplete-information capital market equilibrium with heterogeneous expectations and short sale restrictions (1996)
    Springer
    Review of quantitative finance and accounting 7 (1996), S. 119-136 
    Details
    ISSN: 1573-7179
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract This article extends Merton's (1987) asset-pricing model under incomplete information to consider the situation when investors' beliefs are divergent and short selling is restricted. The article finds that the diversity of beliefs increases the mean variance inefficiency of the market portfolio and the shadow cost of information. However, the inefficiency of the market portfolio due to divergent beliefs is mitigated by short-sale restrictions. The article also finds that the effect of firm size is intertwined with the residual return variance risk. Consistent with the findings of Levy (1978) and Carroll and Wei (1988), the residual return variance plays an important role in determining the risk and risk premium of each security. Finally, the shadow cost of information is larger and the equilibrium security return is higher when expectations are more diverse. And the effects of divergent beliefs on both information cost and required rates of returns are negatively related to the relative size of investor base for a particular security.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00243974
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  • 8
    Electronic Resource
    Electronic Resource
    Multivariate regression tests of the arbitrage pricing theory: The instrumental-variables approach (1991)
    Springer
    Review of quantitative finance and accounting 1 (1991), S. 191-208 
    Details
    ISSN: 1573-7179
    Keywords: arbitrage pricing theory ; instrumental-variables approach ; OLS method ; proxy problem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract This article expands the theoretical basis upon which empirical testing of the arbitrage pricing theory (APT) rests. Specifically, it specifies linear restrictions for worlds in which the APT holds. These restrictions may, in principle, be tested. Since the regressors in the model are only “noisy” proxies for a specific linear transformation of the factors or mimicking portfolios, testing regressions suffer from an errors-in-variables problem. The standard econometric treatment for this problem is the instrumental-variables approach. A size-based example is employed to compare the test results derived from the instrumental-variables approach to those obtained via the ordinary least squares (OLS) method. The results from both methods cannot reject a two-factor APT for the size-sorted portfolio sample.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409672
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  • 9
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    Reconstructing quatewary environments of Taipei Basin with constraints from organic carbon isotopic analysis (1998)
    Springer
    Details
    Publication Date: 1998-08-01
    Print ISSN: 1001-6538
    Electronic ISSN: 1861-9541
    Topics: Natural Sciences in General
    Published by Springer
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  • 10
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    Interactive effects of cadmium and aluminum on growth and antioxidative enzymes in soybean (2008)
    Springer
    Details
    Publication Date: 2008-03-01
    Print ISSN: 0006-3134
    Electronic ISSN: 1573-8264
    Topics: Biology
    Published by Springer
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