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Compatibility Groups among fi− R Factors
Nature, 1971TRANSMISSIBLE R factors in bacteria are divisible into two main classes, fi+ (fertility inhibition +) and fi−, according to their effect on F mediated conjugation1. fi+ R factors determine F-like pili2. Some fi− R factors determine pili similar to those specified by col I (I-type pili)3 which can be recognized as receptors for I-specific phages like ...
N, Datta, R W, Hedges
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The molecular nature of R-factors
Journal of Molecular Biology, 1966The acquisition of infectious multiple drug resistance factors by Proteus mirabilis was correlated with the addition of one or more physically recognizable, native, satellite DNA fractions. The spontaneous loss of one or more drug resistance characteristics carried by R-factors was correlated with either an apparent loss of particular density regions
Stanley Falkow +3 more
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R Factors in X-ray fiber diffraction. II. Largest likely R factors
Acta Crystallographica Section A Foundations of Crystallography, 1989The largest likely R factor (that for a structure uncorrelated with the correct structure) is smaller for an X-ray fiber diffraction analysis than for a traditional single-crystal analysis. For example, the largest likely R factor for tobacco mosaic virus determined by fiber diffraction at 3 A resolution is 0.31, compared to 0.59 for a single-crystal ...
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Cancer and the unavoidable R factor
Science, 2017Cancer Etiology Most textbooks attribute cancer-causing mutations to two major sources: inherited and environmental factors. A recent study highlighted the prominent role in cancer of replicative (R) mutations that arise from a third source: unavoidable errors associated with DNA replication. Tomasetti et al.
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Independence number, connectivity, and r‐factors
Journal of Graph Theory, 1989AbstractWe show that if r ⩾ 1 is an odd integer and G is a graph with |V(G)| even such that k(G) ⩾ (r + 1)2/2 and (r + 1)2α(G) ⩽ 4rk(G), then G has an r‐factor; if r ⩾ 2 is even and G is a graph with k(G) ⩾ r(r + 2)/2 and (r + 2)α(G) ⩽ 4k(G), then G has an r‐factor (where k(G) and α(G) denote the connectivity and the independence number of G ...
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