Multiple, identical copies of RXLR genes certainly arise from positive selective pressures since these effectors can suppress plant defenses and enhance pathogen growth [19], [20], [22].
Fu and Li's F statistic focuses on singleton alleles, which can arise during positive selection.
Since NEPC cells lack AR expression, they probably arise by positive selection following AR suppression, thus providing an adaptive mechanism to achieve castration resistance [ 5].
To model phenotypic assortment, the approach described by Fulker (1982), and Neale et al. (1994) was applied which assumes spouse correlations arise through positive phenotypic assortative mating (Fig. 1b).
Differences in signalling amplitude and duration can arise from positive or negative feedback loops within the same signalling pathway (Santos et al., 2007) or activation of additional signalling components (York et al., 1998).
Generally desires arise from positive emotions such as generosity, kindness, intelligence, compassion and so on, or negative emotions such as insecurity or neediness, fear, anger & frustration, envy, ill will, greed, ignorance, etc.
Furthermore, in [9], the positive delayed feedback is considered, and they show that the scenario arising for positive feedback is much richer than with negative feedback.
Whatever the exact mechanism, the extra copies of the amylase gene seem to have arisen through positive selection, the researchers said.
Ignition, corresponding to a high fuel cell current, arises from positive feedback between the water produced by the reaction and the transport of protons in the membrane.
The effect arises when positive electrons form small gangs that behave like single particles with a total charge that is some fraction of an electron's charge.
