All articles A–Z

Holocene

The Holocene, also known as the Holocene epoch, is the current geological epoch, beginning 11,700 years ago with warming that ended the Younger Dryas and divided since 2018 into the Greenlandian, Northgrippian, and Meghalayan stages.

Holocene and modern bivalve sclerochronology calibration studies

Bivalve sclerochronology calibration links shell growth increments and shell chemistry, especially δ18O, to dated instrumental climate measurements, turning Holocene and older bivalve shells into quantitative paleoclimate records.

Holocene calendar

The Holocene calendar, also called the Human Era calendar, adds 10,000 years to AD numbering so that year 1 falls near the start of the Holocene epoch.

Holocene extinction

Holocene extinction, also called the sixth mass extinction or Anthropocene extinction: ongoing human-driven species loss during the last ~11,500 years, with modern extinction rates estimated at tens to hundreds of times background levels, though its mass-extinction status is debated.

Holocentric chromosome

Holocentric chromosome (holokinetic, diffuse centromere): a chromosome with kinetochore activity along nearly its whole length, tolerating fragmentation; evolved independently at least 13 times in plants and animals, first described 1935.

Holocephali

Holocephali, also known as holocephalans, is a subclass of cartilaginous fish containing the chimaeras, or ghost sharks, with upper jaws fused to the skull and a fossil record reaching back almost 360 million years.

Oct 21, 2026

Holochilus

Holochilus (marsh rats) is a genus of large, semiaquatic, herbivorous sigmodontine rodents in open wetlands across South America, from northern South America to central Argentina, with six or more recognized species and a complex taxonomic history.

Oct 21, 2026

Holodiscus discolor

Holodiscus discolor, oceanspray or creambush (Rosaceae), a deciduous arching shrub native from British Columbia to Mexico, with creamy white flower sprays, four varieties, fire-adapted, valuable to native bees.

Holodomor

Holodomor (Голодомор), the man-made famine of 1932–1933 in Soviet Ukraine under Stalin, caused by forced collectivization and grain requisition; killed at least 4 million; recognized as genocide by Ukraine, disputed internationally.

Holodomor genocide question

The Holodomor genocide question debates whether the 1932-1933 Soviet-induced famine in Ukraine (Holodomor, Голодомор) constitutes genocide under the 1948 UN Convention or a crime against humanity, centering on intent, Lemkin's four-stage account, and post-2022 state recognition.

Holofernes

Holofernes (Ὀλοφέρνης) is the Assyrian army commander in the Book of Judith who besieges Bethulia and is beheaded by the widow Judith; not attested historically, he became a major subject in European art and literature.

Oct 22, 2026

Holographic acoustic tweezers

Holographic acoustic tweezers are devices that use holographically shaped sound radiation forces to trap and move multiple particles without contact, first demonstrated in 2018 by Asier Marzo and Bruce Drinkwater.

Holographic dark energy

Holographic dark energy (HDE) is a class of cosmological models in which dark energy's density is set by the holographic principle, proposed by Miao Li in 2004.

Holographic imaging

Holographic imaging, also known as millimeter-wave holographic imaging, records a wave's interference pattern to preserve amplitude and phase, reconstructing 3D images for security screening and sensing.

Holographic interference microscopy

Holographic interference microscopy is a coherent optical technique applying holographic interferometry to microscopy, quantitatively measuring nearly transparent phase objects like living cells, recovering optical phase with nanometer-scale axial sensitivity.

Holographic interferometry

Holographic interferometry is an optical technique that reveals small changes in an object's shape or refractive index as fringe patterns, used in nondestructive testing and vibration analysis.

Holographic microscopy

Holographic microscopy is a label-free imaging technique that reconstructs the 3D structure of transparent specimens from interference patterns, yielding quantitative phase maps of living cells.

Holographic optical elements

Holographic optical elements (HOEs) are volume holograms used as thin, flat optical components that can replace lenses, prisms, and mirrors, notably in augmented reality displays.

Holographic optical tweezers

Holographic optical tweezers (HOTs) are an optical manipulation technique in which a computer-generated hologram splits a single laser beam into hundreds of traps in 3D, invented by Eric Dufresne and David Grier in 1997.

Holographic principle

The holographic principle, also known as holographic duality, is a conjecture in quantum gravity holding that a spacetime region's physics, including gravity, is fully described by its boundary.

Holographic QCD

Holographic QCD, also called the AdS/QCD correspondence, is a theoretical framework using gauge/gravity duality to study non-perturbative quantum chromodynamics, with applications to neutron stars and the quark-gluon plasma.

Oct 22, 2026

Holographic quantum error-correcting code

A holographic quantum error-correcting code is a quantum code encoding bulk degrees of freedom of a hyperbolic space onto its boundary, modeled on the AdS/CFT correspondence.

Holographic reconstruction

Holographic reconstruction is a computational imaging method that numerically recovers an object's amplitude and phase from recorded holograms, applied across optical, electron, and X-ray imaging, where the recovered phase carries quantitative information invisible to ordinary cameras.