Practical problems include the difficulty of getting tourist visas from Libyan embassies: in one change, group visas can be obtained by travel companies on arrival.
The main factors that prevent their use and generalization on wood chip trucks in Quebec include the difficulty in installing them and their unadaptability to the northern climate.
The foremost concerns in applying topology optimization to bone remodeling include the difficulty of handling large-scale problems and associated huge computational cost.
The problems of a peyotero, he said, include the difficulty of finding ranches willing to lease their lands for harvesting, errant bullets from hunters in deer season, rattlesnakes the size of logs and the continuing flux of laws governing peyote.
Their inability to hit a target at distances >20 m likely relates in part to their inexperience with target throwing, but additional factors most likely include the difficulty of aiming with a parabolic trajectory and the target height.
The technical challenges include the difficulty in defining tractable single-gene trait development strategies, the logistics of moving traits from initial to commercial genetic backgrounds, and the disconnect between conditions in farmer's fields and controlled environments.
Murtaza's objections to drone warfare include the difficulty of surrender, the Obama administration's looseness in defining potential targets and the common criticism that the relative cheapness of drone warfare encourages less public scrutiny.
They include the difficulty of estimating true times of speciation and extinction using occurrence data from the fossil record; the inappropriateness of richness alone as a measure of long-term ecological change; and the confounding of preferential preservation and preferred true habitats in fossilized marine organisms.
They also include the difficulty of making a diagnosis when there are numerous concurrent conditions in elderly patients that could also lead to nephropathy, the varied clinical manifestations of these conditions, and the lack of clinical trials specifically designed to evaluate the effect of drugs in this age group.
The challenges in mathematical modeling of bioenergy systems which include the difficulty in generalizing a bioenergy system, the lack of physical and chemical properties of various biomass, the complexity of multi-scale processes and the validation of the models were then discussed.
These include the difficulty of working out which party has the greater claim to seats after the coming boundary changes and the likelihood that Tory voters would be more likely to heed the pact and vote Lib Dem than their new Lib Dem allies, who might well just go off and vote Labour.
