However, identifying and interpreting geochemical biosignatures of microbial life is challenging and involves careful differentiation between signatures of biological processes and those of abiological
Fractionation mechanisms are not well understood, but calcium isotope fractionation during abiological
and biological mineralization is well documented, and probably accounts for much of the observed natural variation in [delta][sup.44]Ca (1, 4, 6).
He takes it for granted that this is an abiological
world, characterized by a "museum of rockscapes," regolith, ejecta, mesas, and craters.
"I'm staying on the fence because that critical piece of lab work that demonstrates that they're biological or abiological
is still in progress."
ponds, which are sometimes called "poison systems," contain no fish or plants.
(1991) have argued that the almost immediate disappearance of [N.sup.15] from inorganic N pools, characteristic of pool-dilution studies, resulted from physical processes in soil; they suggested that [sim]10% of the [[blank].sup.15][[NO.sub.3].sup.-] added in their study was incorporated into soil organic matter via an undescribed abiological
By the 'selective regime' of a trait I mean the total set of abiological
and biological (including social, developmental and physiological) factors in the environment of the trait which potentially affect the fitness of individuals with that trait.(18) In contradistinction to previous approaches, RF is not a definition of intrinsic function, but of 'function with respect to R', The rationale for proposing that function is specifiable only relative to a selective regime is simply that function is defined in terms of a trait's contribution to average individual fitness, and that is specifiable only with respect to a selective regime (Brandon ; Richardson and Burian ).
The agreement came two days after abiological
warfare symposium at the annual meeting of the American Association for the Advancement of Science.
self-assembly via coordination: formation of 2D metallacycles and 3D metallacages with well-defined shapes and sizes and their chemistry," Journal of the American Chemical Society, vol.
and biological subsurface processes have been proposed to explain the presence of this methane.