Memory formation is generally accepted to rely on synaptic plasticity (Bear 1996; Martin et al. 2000), yet it can be problematic to quantify the interdependence of the two by simultaneous assessment: physiological plasticity mostly remains indiscernible to current electrophysiological recording approaches, and artificially induced plasticity alone is no surrogate for mammalian learning.
To date, it has been problematic to accurately quantify multiple nucleic acid sequences, representing microbial targets, in multi-target mixtures using oligonucleotide microarrays, primarily due to nonspecific target binding (i.e., cross-hybridization).
Her accounts provide a rare glimpse of the scale of off-street prostitution in Britain, which is notoriously problematic to quantify.
It is inherently problematic to quantify the fitness of clonal soil microbes such as mycorrhizal fungi (see [ 53] for a discussion of the problem).
The combination of high spatial and temporal variability and substantial uncertainty associated with fire CO2 emissions can be problematic to efforts to develop remote sensing, monitoring, and inverse modeling techniques to quantify carbon fluxes at the continental scale.
Taken together, we believe that the proposed experiment would be difficult to interpret, problematic to quantify, and provide little biologically relevant insight into the host responses that are naturally triggered by colonizing V. fischeri cells.
While phylogenetic analyses or strong differentiation observed using population genetic statistics (e.g. FST) may allow identification of evolutionary significant units, these approaches can be problematic for quantifying gene flow under recent divergence because they do not adequately separate the historical effects of shared ancestry from contemporary gene flow [13], [14].
However, study of superoxide, particularly in vivo, can be problematic because it is difficult to quantify, and to manipulate without knocking out part of the antioxidant defence.
