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Symbiotic nitrogen fixation by Rhizobium meliloti requires the developmentally specific expression of certain bacterial genes. One set of these genes encodes the subunits of nitrogenase, the enzyme responsible for the reduction of atmospheric dinitrogen to ammonia, and another set consists of closely linked genes also essential for nitrogen fixation.(More)
Because mortality accumulates with age, Fisher proposed that the strength of selection acting on survival should increase from birth up to the age of first reproduction. Hamilton later theorized that the strength of selection acting on survival should not change from birth to age at first reproduction. As organisms in nature do not live in uniform(More)
Environmental temperature can modify not only rates of ectotherm growth, development, and reproduction, but also, at the extremes, temperature can limit survivorship and ultimately fitness. We studied ectotherm populations from a latitudinal gradient to understand how alterations in the thermal environment (e.g., rapid climate change) may affect the(More)
We report a measurement of the longitudinal alignment A L of the recoil nucleus in the µ − + 14 N(1 + , 0) → ν µ + 14 C(2 + , 7012) transition. The experiment was performed on the M9B beamline at the TRIUMF cyclotron via the measurement of the Doppler lineshape of the subsequent 14 C(2 + , 7012) → 14 C(0 + , 0) gamma-rays. We compare our result A L = 0.60 ±(More)
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