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111.
Koshland DE 《Science (New York, N.Y.)》1987,235(4787):405
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Chelimsky E 《Science (New York, N.Y.)》1991,254(5029):226-231
It is often said that a major impediment to effective government is the lack of research knowledge underlying the development, implementation, and assessment of federal policies and programs. An examination is made here of the causes of (i) some continuing failures in integrating research information with decision-making and (ii) some notable successes of the past two decades in matching research capabilities with policy needs. Six recommendations are made to facilitate and further the progress that has recently been achieved. 相似文献
117.
Culotta E 《Science (New York, N.Y.)》1991,252(5014):1792-1793
118.
Marshall E 《Science (New York, N.Y.)》1991,252(5013):1609
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In faeces and ileal digesta samples of 31 intact (INT) as well as 73 surgically differently prepared pigs bacterial fractionations and 2.6-diaminopimelic acid (DAP) estimations were carried out in order to calculate the bacterial N proportion in faeces N and digesta N after feeding various diets. Because of a high individual variability and the analytical variation width of the DAP/N-ratios no distinct influences of the fed diets could be found. The average DAP/N-values in the faeces (0.224) of INT pigs ranged in the same magnitude as in the digesta (0.0272) of ileorectostomized (IRA) pigs with open colon descendens (IRAo), where a digesta backflow is possible. Distinct lower DAP/N-ratios (0.0125 resp. 0.0043), however, were found in the digesta of pigs with ileo-caecal cannulae (IZB) or IRA pigs with closed colon (IRAg). On the base of various premises (N of the "bacterial fraction" C is only bacterial N; the DAP found in fraction A originates from intestinal bacteria adhering to feed particles) conducted calculations of the bacterial N proportions (in per cent of total N) led to the following data: Faeces of INT pigs: 43.0 ... 68.2 vs. 69.6 ... 89.0; digesta of operated pigs (except protein free diet) IRAo: 22.3 ... 57.0 vs. 46.2 ... 73.8; IZB: 17.0 ... 35.7 vs. 25.2 ... 53.6; IRAg (only 3 pigs): 23.6 vs. 24.2. The proportion of bacterial N in the digesta N of protein free fed IRAo pigs was 22.0 vs. 22.6%. 相似文献
120.