Slowing of electrochemical film growth as the deposited oxide restricts electron or ion transport. Increasing thickness increases the transport barrier even while dissolved precursor remains available.

A ratio translating a background yield in a particle-physics control region into its yield in a signal region. It may be estimated with simulation and calibration measurements. Its uncertainty must include acceptance, response and physics differences between the regions; contaminating backgrounds are subtracted or fitted jointly. A profile likelihood can constrain the control and signal counts together rather than treating the transferred estimate as exact.

An experiment at the Large Electron–Positron Collider. Reconstructed W decays were used to test electroweak triple gauge couplings.

A magnetic spectrometer on the International Space Station measuring charged cosmic-ray composition and spectra. It searches indirectly for dark-matter annihilation products, not neutral halo WIMP nuclear scattering.

An approximation to a heavy-hadron decay in which one heavy quark undergoes a weak decay and the other constituents are treated as spectators. The inclusive leading width is approximated by a free-quark width, summed over allowed final states. confinement, final-state masses, strong-interaction corrections and interactions with spectator constituents limit quantitative lifetime predictions.

For a parent moving at $\beta c$ and decaying into two photons of equal laboratory energies, momentum conservation gives photon directions symmetric about the parent direction with $\cos \theta =\beta$. The opening angle is $2\arccos \beta$. In the parent rest frame the photons are opposite and perpendicular to the boost direction.

A CERN electron–positron collider. Its higher-energy operation made W-pair production available for measurements of electroweak triple gauge couplings.

An allocation to current offspring that carries an opportunity cost for other reproductive opportunities. Time spent near offspring is not automatically an investment of the same value in both sexes.

Care supplied by both parents. It can create shared offspring benefits alongside conflict over which parent bears the costs.

Dependence on host-provided resources, physical conditions, signals or transmission opportunities; the required functions vary greatly among parasite lineages.

An organism whose life cycle requires a host; survival of a transmission stage outside a host does not establish host-independent reproduction.

Evolution of host-independent growth from a host-dependent lineage. It requires replacing host-provided functions, not merely losing virulence or host-invasion genes.

A distal finger or toe and its corresponding skeletal organization. Positional assignment, morphology and developmental identity must be distinguished when comparing reduced hands.

An appendage with an inherited digit-bearing organization, which can be modified or lost in descendant lineages.

A regulator and ubiquitin ligase that restrains p53 abundance and activity. Induction of MDM2 by p53 provides negative feedback in the stress response.