However, a major difficulty arises with its application to general gas mixtures where the mole ratios of the participating components are not constant.
However, a major difficulty for source tagging is that different manufactures (and retailers) often use different types of tags (for e.g., AM vs. RF EAS tags), each requiring corresponding detection and removal equipment (Beck 2002).
However, a major difficulty in the use of SUA is the difficulty in isolating the same neurons over time [7], [10].
However, a major difficulty lies in the comparability of data that come from different places and times.
However, a major difficulty in GSM comparisons and reconstructions is to integrate data from different resources with different nomenclatures and conventions for both metabolites and reactions.
However, a major difficulty in achieving asymmetric catalysis in aqueous media is the weakness of non-covalent interactions between substrates, chiral ligands, and metal ions under competitive polar conditions.
However, a major difficulty in understanding how IGFBP5 functions in this capacity is the paradoxical observation that ectopic overexpression of IGFBP5 in breast cancer cell lines results in suppressed cellular proliferation.
However, a major difficulty in studying multisite phosphorylation from a system's perspective has been the uncertainty whether simultaneous or successive phosphorylation occurred at the different sites on the same protein and whether the multiple sites were phosphorylated by the same or different protein kinases.
However, it is a major difficulty of most existing approaches that each of these tasks imposes heterogeneous requirements on the representation.
However, selecting the initial temperature for calculating accumulated temperature has been a major difficulty in bioclimatology because it may differ substantially in plants of the same species when influenced by varying environmental factors (Heide 1993; Murray et al. 1989).
