All articles starting with E

Extended Kalman filter

The extended Kalman filter (EKF) is a state-estimation algorithm applying the Kalman filter to nonlinear systems by linearizing about the current estimate, developed at NASA Ames in the early 1960s for Apollo lunar navigation.

Extended mind thesis

The extended mind thesis, from Clark and Chalmers' 1998 paper, holds that cognitive processes extend beyond the brain to include external resources like notebooks and devices, defended via the parity principle and contested by the coupling-constitution fallacy objection.

Extended periodic table

The extended periodic table is the theoretical extension of the periodic table beyond oganesson, element 118, into a hypothetical eighth period beginning with element 119.

Extended play

Extended play (EP): a music release between a single and an album, usually 4-6 tracks of 15-30 minutes. Originated with RCA Victor's 7-inch 45 rpm EP record of 1952; classified today by Spotify, Apple Music, and chart rules such as the UK's 25-minute threshold.

Extended precision

Extended precision is an IEEE 754 floating-point format exceeding its associated basic format in precision and range, in practice usually Intel's x87 80-bit format with 64 significant bits.

Extended producer responsibility

Extended producer responsibility (EPR) is a policy approach, originating in the early 1990s, that makes producers finance and often organize the collection, recycling, and disposal of their products after use.

Oct 20, 2026

Extended Radical Mastectomy

Extended radical mastectomy is a breast cancer operation adding chest wall and internal mammary node removal to the radical mastectomy, introduced by Jerome Urban in 1951.

Extended Range Attack Munition

The Extended Range Attack Munition (ERAM) is a low-cost, precision-guided, air-launched cruise missile developed by the United States Air Force for Ukraine's fighters, first live-tested in 2026.

Extended spectrum beta-lactamase producing Escherichia coli

ESBL-producing Escherichia coli (ESBL-Ec): E. coli strains making extended-spectrum beta-lactamases, mainly CTX-M-15 in pandemic clone ST131, resistant to penicillins and cephalosporins, often carbapenem-treated; global intestinal carriage about 17.6 to 25.4%.

Sep 29, 2026

Extended thymectomy

Extended thymectomy is an operation that removes the thymus gland together with the surrounding anterior mediastinal fat, from diaphragm to thyroid, used mainly to treat myasthenia gravis.

Extended Validation Certificate

An Extended Validation (EV) certificate is an X.509 TLS server certificate issued under the CA/Browser Forum's EV Guidelines, which require verification of the controlling organization's legal identity.

Sep 29, 2026

Extended X-ray absorption fine structure spectroscopy

Extended X-ray absorption fine structure (EXAFS) spectroscopy is an element-specific X-ray technique that determines which neighbors surround an element, at what distances and numbers, probing local structure within about 5 Å without requiring long-range crystalline order.

Extended-range electric vehicle

An extended-range electric vehicle (EREV) is a plug-in vehicle whose wheels are driven only by an electric motor, with an onboard engine acting solely as a generator.

Extended-reach drilling

Extended-reach drilling (ERD) drills oil and gas wells whose horizontal reach is at least twice their vertical depth, coined by Mobil Oil in the early 1980s.

Extended-spectrum beta-lactamase PER-1

PER-1 (Pseudomonas extended resistant) is a class A extended-spectrum beta-lactamase first found in 1993 in a Turkish patient's Pseudomonas aeruginosa isolate in France; it hydrolyzes ceftazidime, is clavulanate-inhibited, and is widespread in Turkey.

Extended-spectrum beta-lactamase producing Klebsiella pneumoniae

ESBL-producing Klebsiella pneumoniae: hospital Gram-negative pathogen carrying extended-spectrum beta-lactamases (TEM, SHV, CTX-M) that inactivate penicillins, cephalosporins, and aztreonam; treated with carbapenems per MERINO trial evidence.

Extended-Wear Contact Lenses

Extended-wear contact lenses (continuous-wear lenses) are soft, usually silicone hydrogel, lenses approved for overnight wear from one to six nights up to 30 days; they carry a manyfold higher keratitis risk than daily wear.

Extendible cardinal

An extendible cardinal is a cardinal κ in set theory such that every rank segment starting at κ can be elementarily copied into a higher one.

ExtendSim

ExtendSim, originally released as Extend in 1988 by Imagine That Inc., is commercial simulation software for building dynamic models of continuous, discrete event, and mixed-mode systems.

ExteNet Systems

ExteNet Systems, formerly ClearLinx Network Corporation, is a telecommunications infrastructure company in Lisle, Illinois, founded in 2002, that builds distributed antenna systems and small-cell networks.

Extensible Authentication Protocol

The Extensible Authentication Protocol (EAP) is an authentication framework defined in RFC 3748 that negotiates multiple authentication methods over links such as PPP or IEEE 802.

Extensible Metadata Platform

The Extensible Metadata Platform (XMP) is an Adobe standard for embedding metadata such as titles, keywords, and copyright information into files like JPEG and PDF, introduced in 2001.

Oct 22, 2026

Extensile and contractile active matter

Extensile and contractile active matter are the two sign classes of active stress in energy-consuming materials, distinguishing units that push outward from those that pull inward.

Extensin-like

Extensin-like proteins and domains carry the Ser-Pro3-5 repeats of plant cell wall extensins but differ in architecture, spanning PERKs, LRXs, formins, hybrid EXTs, and annotated genes such as Arabidopsis AT2G43150.

Extension principle

The extension principle is a rule in fuzzy set theory, introduced by Lotfi Zadeh, that extends ordinary functions and relations to fuzzy sets and underlies fuzzy arithmetic.

Extension spring

An extension spring, also called a tension spring, is a close-wound helical spring that stores energy when stretched, with hooks or loops at its ends for attaching parts.

Extensional rheology

Extensional rheology, also called elongational rheology, is the study of how materials respond to stretching rather than shearing, measured through extensional viscosity, first examined by Trouton in 1906.

Extensional viscosity

Extensional viscosity, also called elongational viscosity or Trouton viscosity, is a fluid's resistance to stretching rather than shearing flow, introduced by Frederick Trouton in 1906.

Extensive air shower

An extensive air shower (EAS) is a cascade of secondary particles in the atmosphere produced when a high-energy cosmic ray collides with an air nucleus.