Power output or input divided by the relevant mass, commonly expressed in watts per kilogram. Device-level and active-material values cannot be compared without stating their different mass bases.

A degeneracy between adiabatic electronic states with characteristic splitting in suitable nuclear-coordinate directions. It can connect to Jahn-Teller dynamics in open-shell triangular molecules.

A correlation between many-electron states classified by total spin and spatial symmetry along a nuclear path. Orbital occupations, spin adaptation and configuration interaction are needed; one-electron energy curves alone are not a state diagram.

Reduced or absent fertility of hybrid offspring. It must be distinguished from failure to mate or reduced viability before reproductive maturity.

Control of the rate or pattern of biological translation. ribosome occupancy depends on initiation and passage, so more occupied ribosomes need not mean more completed protein.

Artificial recruitment of a candidate effector to a chosen RNA through a separate recognition module. It tests activity after recruitment while bypassing native recognition; physiological targeting and necessity require independent evidence.

The time for half of an RNA molecular population to disappear under specified conditions. For a homogeneous first-order decay process it equals $\ln 2/k_{\mathrm{d}}$; ongoing synthesis and changing biological cell states complicate abundance measurements.

Degradation of RNA molecules. RNA abundance reflects both production and decay, so a steady-state abundance difference alone does not establish a change in stability.

The spatial distribution and targeting of messenger RNA within a biological cell. concentration enrichment, total fraction recruited, residence time and transport are different observables.

Movement of RNA from the nucleus to the cytoplasm in the relevant eukaryotic pathway. Processing, recognition and quality control can be coupled to export; export is distinct from transcription or subsequent biological translation.

If every allowed input density operator has support of a positive operator inside a subspace with orthogonal projector $P$, completeness need only equal $P$ on that subspace. To define a measurement on the full Hilbert space, one can append $M_{\perp }=I-P$ when the original operators act only on the subspace. The added outcome has zero probability on supported inputs. The effects $M_r^{†}{M}_r$ form a POVM; the operators themselves additionally specify state updates.

A pump feeds an auxiliary high level, rapid relaxation populates the upper laser level, and rapid decay empties the lower laser level. This separates pumping from the laser transition and helps sustain net stimulated gain. Gain saturation and cavity loss still determine the oscillating steady state.

The coefficient $K$ in a polytropic equation of state $p=K{\rho }^{\Gamma }$. It is spatially constant for one simple polytrope, but need not stay constant between different equilibrium models. For a fixed-composition ideal gas with $\Gamma$ equal to its adiabatic index, $K$ parametrizes specific entropy: $s=c_v\ln K+\text{constant}$ with a suitable dimensional reference inside the logarithm.

For equally spaced nodes $x_0,x_0+h,\dots ,x_0+dh$, write $t=(x-x_0)/h$. The interpolating polynomial is $P(x)={\sum }_{j=0}^d\left(\genfrac{}{}{0ex}{}{t}{j}\right){\Delta }_h^{j}f(x_0)$. A table of forward differences supplies its coefficients; for a polynomial of degree at most $d$, the formula reproduces the function exactly.

Shortening of an RNA poly(A) tail. For many cytoplasmic messenger RNAs, this contributes to progression toward decay.

An extinction pattern with four dark arms produced, for example, by a radial arrangement of local optical principal directions between crossed polarizers. The local intensity factor ${\sin }^2(2\phi )$ vanishes along the polarizer axes. Such a radial-material pattern need not be a conoscopic interference pattern.

A conoscopic interference pattern is the direction-dependent pattern obtained when a polarizing microscope examines convergent illumination passing through a birefringent specimen. Different positions in the observed angular pattern correspond to different propagation directions through the specimen, and hence to different accumulated phase retardations.

A thin crystal between crossed polarizers can therefore show bright and dark bands even with nearly uniform thickness. Inspecting the angular pattern, rather than an ordinary image of specimen texture, helps identify optical-axis directions. The pattern depends on crystal orientation, thickness and wavelength; it is not a map of surface height.

Rotating a uniform crystallite around a fixed propagation direction changes the crossed-polar intensity factor ${\sin }^2(2\alpha )$. Extinctions repeat every90degrees and maxima occur45degrees away. Similar interference colour can coexist with different brightness if retardation is similar but azimuth differs.

For a vacuum plane electromagnetic wave, a Lorentz boost multiplies both transverse Jones vector amplitudes by the same positive Doppler factor when the basis is carried to the aberrated ray. Their ratio and phase difference therefore remain unchanged. All Stokes parameters gain the same squared factor, leaving normalized parameters, ellipse shape, handedness and degree of polarization unchanged. This does not mean the propagation direction or the components in an arbitrarily fixed pair of spatial axes remain unchanged.

Invariance under spacetime translations and Lorentz transformations. A scalar action with constant coefficients and contracted Lorentz indices has this symmetry when its domain and boundary conditions also permit the transformations.