What I find more challenging, however, are the more serious and upsetting cases.
More challenging, however, is the need to square Procopius's portrait of Theodora with the shimmeringly jewel-encrusted empress who would end up a saint of the Orthodox church.
In the case of Perepilichnyy, the task of working out when, how and by whom a poison could have been administered may be more challenging, however, given that the forensic investigation began a full three weeks after his death.
Identification can be more challenging, however, in more southerly and southeasterly breeding areas and in winter, where extensive distributional and habitat overlap can occur with other superficially similar species: Brown-crested (M. tyrannulus), Great Crested (M. crinitus), Dusky-capped (M. tuberculifer), and Nutting's (M. nuttingi) flycatchers.
More challenging, however, is their finding that, in recent decades, employment growth has not been evenly distributed but rather "polarized," in the sense that the United States and other developed economies are producing large numbers of jobs for highly skilled workers and less-skilled workers — but relatively few in between.
In general, the magnitude of the disturbances during training sessions progressed from less to more challenging; however, the exact sequence was not established a priori.
Tracking users becomes much more challenging indoors, however.
The chromosomal inversions present a more challenging problem, however, as recombination is effectively suppressed in these regions.
In more challenging situations, however, the added stability of a larger diameter can be achieved with the acceptance of an increased risk of bone fracture.
I came to the quick realization that pounding stakes is much more challenging in rocky, however we ended up finishing the first fence in under 3hrs!
Some of those efforts have proven to be more challenging than others, however.
