All articles starting with O

Optically stimulated luminescence dating

Optically stimulated luminescence (OSL) dating determines how long buried quartz or feldspar grains have been hidden from daylight, dating sediments from one year to several hundred thousand years old.

Optichos

Optichos (OptiCHOS), hydrolysed chitosan hydrochloride, is a naturally derived broad-spectrum biofungicide developed at NMBU/BioCHOS, acquired by UPL in 2022, pending EU approval and registered in India.

Optician

Optician (dispensing optician): an eye care professional who fits and dispenses eyeglasses and contact lenses from optometrist or ophthalmologist prescriptions, without diagnosing eye disease; distinct from optometrists and ophthalmologists, regulated in the UK by the General Optical Council.

Optics

Optics is the branch of physics studying the behavior and properties of light and its interaction with matter, together with instruments like telescopes and microscopes.

OPTICS algorithm

OPTICS (Ordering Points To Identify the Clustering Structure) is a density-based clustering algorithm, presented at ACM SIGMOD in 1999, that orders points by reachability distance to find clusters of varying density.

Optics Express

Optics Express is a biweekly, gold open-access peer-reviewed journal covering optics and photonics. Launched in 1997 by the Optical Society of America, it is the most-cited journal in optics.

Optics index

Optics index: NLM-related title of Applied optics (Applied optics. Supplement), the applications-centered optics journal founded 1962 by the Optical Society of America, now Optica Publishing Group, ISSNs 1559-128X and 2155-3165.

OPTIENOX-PCI trial

OPTIENOX-PCI (NCT03145675) is a completed phase 4 randomized trial at Peking Union Medical College Hospital comparing enoxaparin 0.75 vs 0.5 mg/kg and staged vs single dosing for trans-radial coronary angiography and PCI, measured by anti-Xa levels.

Oct 22, 2026

OPTIMADE

OPTIMADE (Open Databases Integration for Materials Design) is a consortium of materials database providers whose standard REST API lets one query work across independent databases.

Optimal control

Optimal control, also called optimal control theory, is the branch of mathematical optimization that drives a dynamical system along a desired trajectory at minimum cost.

Optimal design (statistics)

Optimal design is a statistical method for choosing experiment settings, run allocations, or point weights so a criterion computed from the Fisher information matrix is optimized.

Optimal design of environmental monitoring networks

Optimal design of environmental monitoring networks is the statistical problem of choosing how many stations to operate and where, so measurements carry the most information per unit of budget.

Optimal extraction

Optimal extraction is an algorithm in astronomical spectroscopy, formulated by Keith Horne in 1986, that converts a two-dimensional detector image into a one-dimensional spectrum with the best possible signal-to-noise ratio.

Optimal fingerprinting

Optimal fingerprinting is a regression-based statistical method in climate science that detects climate change signals in observations and attributes them to forcings such as greenhouse gases.

Optimal power flow

Optimal power flow (OPF) is the problem of finding the least-cost operating point for an electric power network, choosing generator dispatch while satisfying power flow laws and operating limits.

Optimal Reciprocal Collision Avoidance

Optimal Reciprocal Collision Avoidance (ORCA) is a decentralized collision-avoidance algorithm in which each agent computes collision-free velocities without communication, introduced by van den Berg and colleagues in 2011.

Optimal stopping

Optimal stopping is the branch of probability theory that studies when to take a once-only action, such as selling an asset or exercising an option, to maximize expected reward.

Oct 10, 2026

Optimal taxation

Optimal taxation is the branch of public economics that studies how governments should design taxes to maximize social welfare, built on Ramsey's 1927 and Mirrlees's 1971 frameworks.

Optimal velocity model

The optimal velocity model is a car-following model of traffic, proposed in 1995, in which each driver adjusts speed to a target velocity set by the distance to the vehicle ahead.

Optimality theory

Optimality Theory (OT) is a constraint-based linguistic framework, introduced by Alan Prince and Paul Smolensky in 1993, in which a grammar is a strict ranking of violable constraints.

OptiMed trial

OptiMed trial: Swiss-Portuguese pre-post, multisite pilot and feasibility study (NCT06688591, withdrawn) of an interprofessional medication management program for polymedicated home-dwelling older adults; distinct from the Dutch Opti-Med cluster randomized trial.

OPTIMISE trial

OPTIMISE trial (NCT06444711), University of Leeds randomised trial testing cardiology-led GP-practice reviews against NICE guidelines in 138 high-risk community-dwelling adults with cardiovascular, renal, metabolic, and pulmonary disease; distinct from OPTIMISE II and OPTIMISE Your Health.

Optimism

Optimism is the psychological disposition of expecting good outcomes, studied as dispositional optimism (Life Orientation Test) and explanatory style; distinct from unrealistic optimism, and linked to lower mortality (RR 0.85) and cardiovascular risk.

Optimist (dinghy)

Optimist dinghy: small single-handed sprit-rigged pram for children, designed 1947 by Clark Mills in Clearwater, Florida; IODA one-design class sailed in over 120 countries, over 150,000 registered boats, 35 sq ft sail, 35 kg hull.

Optimist Party for the Development of Mozambique

PODEMOS (Partido Otimista pelo Desenvolvimento de Moçambique), a democratic socialist Mozambican party founded in 2019 by FRELIMO dissidents under Albino Forquilha; it backed Venâncio Mondlane in 2024 and became the largest opposition party with 43 Assembly seats.