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.
Adenine and guanine are purine bases found in both DNA and RNA. Cytosine is a pyrimidine base found in both DNA and RNA. Thymine and uracil are pyrimidine bases found in only DNA or RNA, respectively.These five nitrogenous bases are all planar molecules, meaning that they are fairly flat and rigid.denine and guanine are purine bases found in both DNA and RNA. Cytosine is a pyrimidine base found in both DNA and RNA. Thymine and uracil are pyrimidine bases found in only DNA or RNA, respectively. These five nitrogenous bases are all planar molecules, meaning that they are fairly flat and rigid.