While it is relatively easy to define what a hurricane or earthquake is, defining a drought is more subjective. Droughts do not have the immediate effects of floods, but sustained droughts can cause economic stress throughout an area. The word drought has various meanings, depending on a person's perspective.
For the software package, see Partition function for Interacting RNAs. Piwi-interacting RNA (piRNA) is the largest class of small non-coding RNA molecules expressed in animal cells. piRNAs form RNA-protein complexes through interactions with piwi proteins.
The RNeasy Micro Kit is designed for isolation of total RNA from small samples such as microdissected tissues and fine needle aspirates, from milligram amounts of fibrous tissues including heart and muscle tissue, and from small numbers of cells down to single cells (e.g., FACS sorted cells).