All articles starting with H
20,046 articles
Hypercarotenaemia
Hypercarotenaemia (carotenemia, carotenodermia), ICD-10 E67.1 / ICD-11 5B90.1, is a benign elevation of blood β-carotene causing yellow-orange skin with spared sclerae, distinguished from jaundice; caused by dietary excess, metabolic disease, or BCO1 variants.
Hypercholesterolaemia
Hypercholesterolemia, also spelled hypercholesterolaemia, is the condition of abnormally high cholesterol in the blood and the most common form of dyslipidaemia, a major modifiable risk factor for heart attack and stroke.
Hypercholesterolemia
Hypercholesterolemia, high blood cholesterol (elevated LDL-C/non-HDL-C), a dyslipidemia and direct cause of atherosclerotic cardiovascular disease; defined as LDL-C ≥130 mg/dL, treated with statins, ezetimibe, PCSK9 inhibitors, bempedoic acid, inclisiran.
HyperCLOVA (model family)
HyperCLOVA is a family of large language models developed by the Korean internet company NAVER, specialized in Korean language and culture, first released in 2021 and expanded into the HyperCLOVA X line.
Hypercomplex number
A hypercomplex number, also called a hypercomplex system, is an element of a finite-dimensional algebra with identity over the real numbers; examples include the quaternions, octonions, and Clifford algebras.
Hypercomputation
Hypercomputation, also called super-Turing computation, studies theoretical models that compute beyond the Turing machine, such as oracle machines, Zeno machines, and relativistic or quantum hypercomputers; no physical hypercomputer has been demonstrated, and its physical realizability remains an open empirical question.
Hyperconjugation
Hyperconjugation, also called σ-conjugation or no-bond resonance, is the stabilizing interaction of a sigma bond, usually C−H or C−C, with an adjacent empty or partially filled p, π, or π orbital.
Hypercrosslinked polymer CO2 sorbents
Hypercrosslinked polymer CO2 sorbents are porous organic adsorbents in which heavily crosslinked aromatic networks bind carbon dioxide, a cheap, stable class of solid sorbents for carbon capture.
Hypercube
A hypercube, also called an n-cube or measure polytope, is the generalization of the ordinary three-dimensional cube to n dimensions; the sequence runs point, segment, square, cube, and tesseract, each step doubling the vertex count.
Hypercube graph
The hypercube graph, also called the n-cube or Boolean cube, is the graph formed by binary strings of length n, with edges between strings differing in one bit.
Hypercube topology
Hypercube topology is an interconnection network for parallel computers where each node connects to neighbors whose binary addresses differ in one bit, giving logarithmic diameter but limiting scalability.
Hyperdimension Neptunia (超次元ゲイム ネプテューヌ)
Hyperdimension Neptunia (超次元ゲイム ネプテューヌ), also called Neptunia, is a Compile Heart and Idea Factory JRPG series set in Gamindustri, starring console-personifying goddesses like Neptune; began 2010 on PS3, includes Re;Birth remakes, Megadimension Neptunia VII, a 2013 anime, and Neptunia Unlimited (2026).
Hyperdimensional computing
Hyperdimensional computing (HDC), also known as vector symbolic architectures, is a family of computational models that represent data as very high-dimensional hypervectors, coined by Pentti Kanerva in 2009.
Hyperdontia
Hyperdontia (supernumerary teeth): a developmental dental anomaly with extra teeth beyond the normal 20 primary or 32 permanent. Prevalence 0.1–3.8% permanent dentition; mesiodens most common; linked to Gardner syndrome and cleidocranial dysplasia.
Hyperdrama
Hyperdrama is the fourth studio album by French electronic duo Justice, released April 26, 2024 on Ed Banger/Because Music, eight years after Woman; it features Tame Impala, Miguel, and Thundercat and scored 71 on Metacritic.
Hyperdrive
Hyperdrive is a 2019 American reality competition series on Netflix, hosted by Mike Hill, Lindsay Czarniak, Rutledge Wood, and Michael Bisping, in which 28 drivers race their hand-built cars through an automotive obstacle course.
Hyperdub
Hyperdub is a London-based independent record label founded in 2004 by Steve Goodman, known as Kode9, best known for releasing Burial's albums Burial (2006) and Untrue (2007).
Hypereia (spring)
Hypereia (Υπέρεια κρήνη, Yperia Krini) is the famous ancient spring of Pherae at modern Velestino, Thessaly, Greece, mentioned by Homer, Pindar, Strabo, and Plutarch; its 5th-century BC fountain house fed a small lake used for irrigation and watermills, and the spring has been dry since 1998.
Hyperelastic bone
Hyperelastic bone is a 3D-printable synthetic bone graft material, 90% hydroxyapatite and 10% biodegradable polymer, developed at Northwestern University, that is elastic, porous, and induces bone formation without growth factors.
Hyperelastic material
A hyperelastic material, also called a Green elastic material, is an elastic material whose stress-strain relationship derives from a single strain energy density function, typical of rubber and soft tissues.
Hyperelastic model
A hyperelastic model is a constitutive law for rubber-like materials in which stress derives from a strain energy density function, making work path independent; named forms include Mooney-Rivlin, Ogden, and Gent.
Hyperemesis gravidarum
Hyperemesis gravidarum (HG) is the severe form of pregnancy nausea and vomiting, affecting 0.3–3.6% of pregnancies, driven by the placental hormone GDF15, causing weight loss and dehydration, and treated with antiemetics, rehydration, and thiamine.
Hyperemesis gravidarum with metabolic disturbance
Hyperemesis gravidarum with metabolic disturbance, ICD-11 JA60.1, is pregnancy vomiting unresponsive to diet and antiemetics, with electrolyte and acid-base imbalance requiring IV fluids, potassium, and thiamine.
Hyperenor Linea
Hyperenor Linea, a linea on Jupiter's moon Europa, IAU-approved 1997, diameter 2,996 km, centered at 12.10S 324.40W; named for a mythological founder of Thebes.
Hyperferroelectricity
Hyperferroelectricity is a proposed class of proper ferroelectricity, introduced in 2014, in which materials keep switchable polarization despite an unscreened depolarization field; no candidate is yet experimentally confirmed.
Hyperfine structure
Hyperfine structure, also called hyperfine splitting or hyperfine interaction, is the small splitting of atomic energy levels by magnetic interaction between the nuclear spin and the electrons.
Hyperfine sublevel correlation spectroscopy
Hyperfine sublevel correlation (HYSCORE) spectroscopy is a two-dimensional pulsed EPR experiment, reported in 1986, that identifies nuclei coupled to an electron spin and measures their hyperfine couplings.
Hyperfinite type II factor
The hyperfinite type II₁ factor, usually written R, is a von Neumann algebra approximated by finite-dimensional matrix algebras, unique of its type, introduced by Murray and von Neumann in 1943.
Hyperfinite type II₁ factor
The hyperfinite type II₁ factor R is the unique infinite-dimensional von Neumann algebra that is a factor, carries a finite trace, and is a limit of matrix algebras.
Hyperfluorescence
Hyperfluorescence is an OLED mechanism in which a TADF sensitizer transfers excitons to a narrowband fluorescent emitter, considered the fourth generation of OLED emitter technology.