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Ohne Zusammenfassung 相似文献
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Fragment sets generated manually from Wiswesser Line Notation have been used to correlate the chemical structures of a group of 79 penicillins with their serum binding activity, using multiple regression analysis. Statistically significant correlations were found, with results in accordance with the generally accepted nature of the binding. Algorithmic methods for the generation of such fragment sets are proposed and the use of various structural representations for structure-property correlation within chemical information systems is discussed. 相似文献
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J. Adamson 《Applied Mathematical Modelling》1983,7(3):173-181
In certain types of hydrodynamic calculation the solution of a field equation, after finite differencing, resolves into the inversion of a singular matrix though with a consistent source. There are no physical or mathematical objections to this in principle, but in terms of computer application round-off error can make the set inconsistent. In this case no solution would be possible and this would indeed be discovered with direct methods of matrix inversion.However, with an iterative method such as ADI well-behaved ‘solutions’ are obtained, leading to satisfactory convergence of the overall problem. This article explains why this is so: it is shown that the difference in the computed field variable from the value appropriate to a consistent source is related to the error in the source by a finite matrix multiplier. Hence if the inconsistency in the source is small, e.g. owing to round-off, the error in the computed field variable is likely to be acceptable. 相似文献
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Measurement Instruction in the Context of Scientific Investigations With Diverse Student Populations
Karen Adamson Walter Secada Jaime Maerten‐Rivera Okhee Lee 《School science and mathematics》2011,111(6):288-299
The purpose of this study was to investigate the impact of a hands‐on science curriculum, which integrates mathematics and supports English language development, on third‐grade students' mathematics achievement—specifically the measurement subscale of the statewide assessment. The data drew from a larger five‐year research and development project consisting of reform‐based science curriculum units and teacher workshops designed to promote effective science instruction while integrating mathematics and supporting English language development. The third‐grade curriculum places a strong emphasis on measurement skills in the context of science inquiry. The third‐grade students' performance on the measurement subscale of the statewide mathematics assessment in the treatment schools was compared with that of comparison schools using a hierarchical linear model. Students at the treatment schools performed significantly higher than students at the comparison schools. The results provide evidence that an integrated approach to mathematics and science instruction can benefit diverse student groups. 相似文献
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Takayama S Thorgeirsson UP Adamson RH 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2008,84(6):176-188
This review covers chemical carcinogenesis studies in nonhuman primates performed by the National Cancer Institute, USA, to provide hitherto unavailable information on their susceptibility to compounds producing carcinogenic effects in rodents. From autopsy records of 401 breeders and untreated controls, incidences of spontaneous malignant tumors were found to be relatively low in cynomolgus (1.9%) and rhesus monkeys (3.8%), but higher in African green monkeys (8%). Various chemical compounds, and in particular 6 antineoplastic agents, 13 food-related compounds including additives and contaminants, 1 pesticide, 5 N-nitroso compounds, 3 heterocyclic amines, and 7 "classical" rodent carcinogens, were tested during the 34 years period, generally at doses 10 approximately 40 times the estimated human exposure. Results were inconclusive in many cases but unequivocal carcinogenicity was demonstrated for IQ, procarbazine, methylnitrosourea and diethylnitrosamine. Furthermore, negative findings for saccharine and cyclamate were in line with results in other species. Thus susceptibility to carcinogens is at least partly shared by nonhuman primates and rodents. 相似文献