The changeable nature of coastal fisheries (i.e., target species, gear types) over short time scales also challenges characterizations of this fisheries sector [24].
Grasslands and savannas form a heterogeneous and patchy mosaic of spectral properties that are challenging for characterization of vegetation states.
Both Hobbes and Bourdin, then, are challenging Descartes' characterization of what it is actually like to dream and it should be clear that these diverging statements about what we do (or do not) typically dream about are at least in principle open to empirical investigation.
Therefore, for rare species and species such as Streptococcus where identification based on 16S gene is challenging, functional characterization should be performed in follow-up studies.
Bar-Tur did not challenge this characterization.
But Israel, more and more, is prepared to challenge that characterization.
When a reporter describes Mr. Sims as angry in a public debate, he will challenge the characterization.
But yesterday, as Mr. Keller stood nearby, Mr. Sulzberger challenged that characterization, saying: "There's no complacency here.
General Odierno challenged the characterization in some news reports that Sunday's election was significantly marred by violence, particularly in Baghdad.
The prosecutor challenged that characterization, arguing that the state had presented a case of substance against a clergyman who betrayed his wife by offering a financially troubled friend $30,000 to murder her in November 1994.
