A partner of Drosha in canonical animal primary microRNA processing.

Recognition and positioning of a primary hairpin help the Drosha complex generate a shorter precursor. Later export and Dicer processing are additional stages, so loss of a mature microRNA can arise from defects at several different steps. ^[ref]

Profiling of preserved ribosomal and small-subunit-associated complexes to distinguish stages including scanning and recycling. Captured distributions remain subject to crosslinking and fragment-selection biases.

An RNA fragment protected from digestion by a ribosome in the assayed preparation. Length, genomic position and frame periodicity help distinguish productive biological translation from other protected RNA.

Frame-related enrichment at a three-base interval in correctly positioned translating-ribosome reads. It supports biological translation but is difficult to establish for very short or low-count reading frames.

Methods that preferentially capture ribosomes near biological translation starts, often using short inhibitor treatments. Candidate peaks require calibration and independent validation.

Contact between successive ribosomes when a following one reaches a stalled or slowly moving predecessor. Collisions can supply regulatory and quality-control signals rather than simply indicating high productive output.

One of the major assemblies forming a ribosome. Small-subunit scanning and reinitiation can persist after release of the large subunit at a short upstream open reading frame.

A group of ribosomes translating one messenger RNA. Occupancy can increase through faster initiation or slower elongation, so the amount of polysomes is not by itself a synthesis-rate measurement.

A protein component of a ribosome. The machinery can combine products of different genomes, especially in an organelle.

A bacterial factor that assists peptide-bond formation at susceptible sequences, including consecutive prolines. Functional maturation of the factor and substrate sequence affect its activity.^[ref]

Formation of a peptide bond by transfer of the growing peptide to an incoming aminoacyl-tRNA. substrate sequence can affect the rate independently of decoding accuracy.

Prolonged delay of a translating ribosome at a particular position. Stalls can reduce completed-chain output and cause ribosome collisions.

An enzyme that processes appropriate double-stranded RNA substrates into small guide-RNA precursors in several RNA interference pathways.

A nuclease participating in primary piRNA processing in Drosophila, distinct from the Dicer cleavage pathway.

An ideal flow model in which all fluid elements have the same transit time. For first-order radioactive decay the outlet-to-inlet radioactive activity concentration ratio is $e^{-\lambda \tau }$.

A continuous reactor with uniform contents. At steady state for first-order radioactive decay, $a_{\mathrm{out}}/a_{\mathrm{in}}=1/(1+\lambda V/Q)$; young material can leave before the mean residence time.

The time a material element spends in a system. In ideal plug flow it equals the volume divided by volumetric flow rate; in a mixed vessel that ratio is a mean and does not guarantee the age of every discharged element.

The spinor boost $\mathrm{diag}(e^{\kappa /2},e^{-\kappa /2})$ changes the component-magnitude ratio by $e^{-\kappa }$. The associated active positive-$z$ Lorentz boost therefore changes the polar half-angle as displayed and leaves azimuth unchanged. Its null-vector time scale changes by $\cosh \kappa +\sinh \kappa \cos \theta$, which must be retained separately when normalizing a spinor to encode direction.

For two coincident observers with relative motion along the sightline to a small distant source, its angular diameter changes by a rapidity factor. A boost toward the source compresses its incoming angular cone: $\tan ({\vartheta }^{\prime }/2)=e^{-\eta }\tan (\vartheta /2)$ for angular radius $\vartheta$. For a small source the larger-to-smaller diameter ratio is $r=e^{|\eta |}$, giving the displayed relative speed. A finite angular size requires the half-angle formula, and arbitrary transverse relative motion cannot be inferred from one diameter ratio alone.