All articles starting with O
9,097 articles
Open Cabildo of Caracas (19 April 1810)
The Open Cabildo of Caracas (Cabildo Abierto de Caracas) was a municipal meeting held on 19 April 1810, when the people of Caracas deposed Spanish Captain General Vicente Emparan.
Open Cabildo of Santiago (18 September 1810)
The Open Cabildo of Santiago (Cabildo Abierto de Santiago) was a town meeting held in Santiago de Chile on 18 September 1810, convoked by Governor Mateo de Toro y Zambrano.
Open carry in the United States
Open carry in the United States is the practice of carrying a visible firearm in public, legal without a permit in 27 states as of 2024.
Open Cascade Technology
Open Cascade Technology (OCCT) is an open-source, object-oriented C++ class library for 3D surface and solid modeling, CAD data exchange, and visualization, developed by the French company Open Cascade SAS.
Open Catalyst 2020
Open Catalyst 2020 (OC20) is a dataset of over 1.2 million density functional theory calculations of adsorbates on catalyst surfaces, released by Facebook AI Research and Carnegie Mellon University in October 2020.
Open Catalyst 2022 (OC22) dataset
The Open Catalyst 2022 (OC22) dataset is a public set of 62,331 density functional theory relaxations of adsorbates on oxide surfaces for training machine learning electrocatalyst models.
Open Catalyst Project
The Open Catalyst Project is a research collaboration between Meta's FAIR and Carnegie Mellon University, launched in 2020 to use AI to find new catalysts for renewable energy storage.
OPEN CCTArrest trial
OPEN CCTArrest (NCT07388342), UZ Brussel trial led by Bert Popelier testing ECG-less gated coronary CT angiography accuracy in resuscitated cardiac arrest survivors without STEMI, 30 patients, 2025-2027.
Open central unrounded vowel
The open central unrounded vowel is a common vowel sound found in Catalan, Mandarin Chinese, Czech, and Dutch, for which the IPA rejected a dedicated symbol in 2011.
Open Charge Alliance
The Open Charge Alliance is a non-profit organization, founded in 2014, that develops and governs the Open Charge Point Protocol, the open communication standard between electric vehicle charging stations and central systems.
Open Charge Point Protocol
The Open Charge Point Protocol (OCPP) is an open communication protocol between electric vehicle charging stations and management systems, maintained by the Open Charge Alliance.
Open cholecystectomy
Open cholecystectomy removes the gallbladder through an abdominal incision, usually a right subcostal one, to treat symptomatic gallstones; it was standard from the 1880s until the 1980s.
Open Closed Open
Open Closed Open (Hebrew: פתוח סגור פתוח, Patuach Sagur Patuach) is the final poetry collection of Israeli poet Yehuda Amichai, published in Jerusalem in 1998, two years before his death.
Open cluster
An open cluster, also called a galactic cluster, is a loosely gravitationally bound group of up to a few thousand stars that formed together and gradually disperses.
Open clusters as tracers of Galactic structure
Open clusters trace Galactic structure because stars born together share a distance, age, and composition, letting astronomers map the Milky Way's spiral arms and disc.
Open coding
Open coding is a qualitative data analysis technique in which researchers break data into segments and attach provisional conceptual labels, called codes, without a predefined framework.
Open collector
An open collector is an integrated-circuit output, also called open drain, that can pull a line low but needs an external pull-up resistor to drive it high.
Open container law
An open container law is a statute banning open alcoholic beverage containers and drinking in the passenger area of a motor vehicle, whether by the driver or passengers.
Open cover
An open cover of a set in a topological space is a collection of open sets whose union contains it, and compactness means every open cover has a finite subcover.
Open D tuning
Open D tuning, traditionally called Vestapol, is a guitar tuning with strings set to D-A-D-F#-A-D, so strumming open sounds a D major chord, popular for slide guitar and blues.
Open DAC 2023
Open DAC 2023 (ODAC23) is an open dataset of density functional theory calculations of CO2 and H2O adsorption on metal-organic frameworks, built by Meta researchers for direct air capture.
Open data
Open data is data anyone is free to use, reuse, and redistribute without legal, technological, or social restriction, most often data from public bodies such as governments.
Open Data Contract Standard
Open Data Contract Standard (ODCS), a Bitol/Linux Foundation vendor-neutral YAML format for data contracts describing dataset schema, quality, SLAs, ownership, and servers; current version v3.2.0; successor to the deprecated Data Contract Specification.
Open Data Product Standard
Open Data Product Standard (ODPS), Bitol's open YAML specification for describing data products (identity, ports, team, AI-agent context), current version v1.1.0; sister of ODCS; distinct from the Open Data Product Specification at opendataproducts.org.
Open Database Connectivity
Open Database Connectivity (ODBC) is a standard API, first released by Microsoft in 1992, that lets one application access many database systems with the same code.
Open defecation
Open defecation is defecating in fields, bushes, water, or other open spaces instead of using a toilet. 354 million people practised it in 2024, down from 1.3 billion in 2000; ending it is SDG target 6.2.
Open Dialogue
Open Dialogue is a psychosocial approach to psychosis and mental health crises, developed in Finnish Lapland, that treats patients in meetings with family and social network.
Open Door Policy
The Open Door Policy was U.S. Secretary of State John Hay's 1899-1900 notes to the great powers calling for equal trading opportunity in China and respect for China's territorial and administrative integrity, the basis of U.S. Far East policy into the mid-20th century.
Open Dynamics Engine
The Open Dynamics Engine (ODE) is a free library for simulating rigid body dynamics, created by Russell L. Smith in 2001 and used in robotics simulators.
Open education
Open education: philosophy that knowledge is a public good, freely shared; centers on OER and open educational practices under open licenses. Landmark policy is the 2019 UNESCO Recommendation on OER.