All articles starting with P

Proxima Fusion

Proxima Fusion is a Munich-based fusion startup founded in 2023 as the first spin-out of the Max Planck Institute for Plasma Physics, developing stellarator power plants.

Proxima Midnight is a Marvel Comics supervillain, member of Thanos' Black Order, created by Jonathan Hickman (first appearance New Avengers Vol. 3 #8, 2013); wife of Corvus Glaive, wielder of a spear that never misses, also in the MCU Infinity War.

Proximal 16p11.2 microdeletion syndrome

Proximal 16p11.2 microdeletion syndrome (16p11.2 deletion syndrome, AUTS14A) is a ~593-kb deletion at chromosome 16p11.2 BP4-BP5 causing developmental and language delay, autism features, and obesity, prevalence about 1/5,000, usually de novo.

Proximal 16p11.2 microduplication syndrome

Proximal 16p11.2 microduplication syndrome is a rare chromosomal disorder caused by an extra copy of a segment of chromosome 16, causing developmental delay, autism, and other features.

Oct 20, 2026

Proximal Gastric Vagotomy

Proximal gastric vagotomy (highly selective, parietal cell vagotomy): ulcer operation dividing vagal branches to the acid-secreting proximal stomach while sparing antral nerves, avoiding drainage; lower side effects but higher recurrence than truncal vagotomy.

Proximal gradient method

The proximal gradient method, also known as proximal gradient methods, is a first-order algorithm minimizing smooth plus nonsmooth objectives, popularized as ISTA for l1-regularized problems.

Proximal point algorithm

The proximal point algorithm, or proximal point method, is an iterative optimization method that repeatedly minimizes a convex objective plus a quadratic penalty centered at the current iterate.

Proximal Policy Optimization

Proximal Policy Optimization (PPO) is a family of reinforcement learning algorithms introduced at OpenAI in 2017, later the training engine of RLHF pipelines behind ChatGPT.

Proximal renal tubular acidosis

Proximal renal tubular acidosis (type 2 RTA, pRTA): rare kidney tubular disease with impaired proximal bicarbonate reabsorption, lowered renal threshold (about 14-18 mEq/L), hyperchloremic normal-anion-gap acidosis, urine pH under 5.5, SLC4A4 or Fanconi syndrome causes, alkali therapy.

Proximal symphalangism

Proximal symphalangism (Cushing symphalangism, SYM1) is a rare autosomal dominant disorder fusing finger joints, carpal and tarsal bones, with conductive hearing loss, caused by NOG or GDF5 mutations.

Proximal Xq28 duplication syndrome

Proximal Xq28 duplication syndrome, also called MECP2 duplication syndrome or Lubs-type X-linked intellectual disability, is a rare X-linked neurodevelopmental disorder from Xq28 duplications under 4 Mb including MECP2, causing male infantile hypotonia, severe intellectual disability, spasticity, seizures, and recurrent infections.

Proximate analysis

Proximate analysis is a set of standardized laboratory tests that partitions a solid fuel such as coal, coke, or biomass into moisture, volatile matter, fixed carbon, and ash fractions.

Proximate cause

Proximate cause in law: an actual cause also legally sufficient for liability, limiting responsibility for remote consequences of conduct. Covers cause in fact, foreseeability and directness tests, superseding causes, eggshell plaintiff, and Restatement reform.

Proximie

Proximie is a London-based health technology company founded in 2016 by NHS plastic surgeon Nadine Hachach-Haram, whose platform lets clinicians virtually join operating rooms and is used in over 500 hospitals.

Proximity effect (electromagnetism)

The proximity effect is the redistribution of alternating current in a conductor caused by the time-varying magnetic field of a neighboring conductor, increasing effective AC resistance.

Proximity extension assay

The proximity extension assay (PEA) is a homogeneous immunoassay, introduced in 2011, in which pairs of DNA-linked antibodies quantify thousands of proteins from microliter plasma samples by PCR or sequencing.

Proximity fuze

The proximity fuze, also known as the VT fuze, detonates a shell, bomb, or mortar round when it senses a nearby target, developed by the United States during World War II.

Proximity labeling

Proximity labeling is a molecular biology technique in which an engineered enzyme fused to a protein of interest tags nearby proteins in living cells for mass spectrometry.

Proximity ligation assay

The proximity ligation assay (PLA) is a bench biology method, introduced in 2002, that detects proteins and their interactions by converting nearby antibody binding into amplifiable DNA.

Proximity ligation-assisted ChIP-seq

Proximity ligation-assisted ChIP-seq (PLAC-seq) is a chromatin conformation capture method, introduced in 2016, that maps long-range DNA interactions anchored at regions bound by a protein of interest.

Proximity operations

Proximity operations, usually paired with rendezvous as RPO, are spacecraft maneuvers in which one vehicle flies near another space object to observe, inspect, service, or capture it.

Proximity Query Package

The Proximity Query Package (PQP) is a C++ library for collision detection, distance computation, and tolerance verification on triangle meshes, written at UNC Chapel Hill and released in 1999.

Proximity sensor

A proximity sensor, or proximity detector, detects nearby objects without physical contact, converting their presence into an electrical signal through electromagnetic, electric, light, sound, or magnetic fields.

Proximity-induced bioorthogonal chemistry

Proximity-induced bioorthogonal chemistry is a chemical biology strategy in which molecular recognition, such as ligand binding, brings two reactive groups close, triggering a bioorthogonal reaction at a chosen site.

Proximity-induced covalent protein modification

Proximity-induced covalent protein modification is a chemical biology strategy in which molecular recognition positions a reactive group beside a target amino acid, enabling selective covalent modification of native proteins in living cells.

Proximity-induced spin–orbit coupling and spin Hall effect in graphene

Proximity-induced spin–orbit coupling in graphene is the transfer of strong spin–orbit coupling from a adjacent transition-metal dichalcogenide such as WS2 or MoS2 into graphene, enabling the spin Hall effect.

Proximity-induced spin–orbit coupling in graphene/TMD heterostructures

Proximity-induced spin–orbit coupling in graphene/TMD heterostructures is the transfer of strong spin–orbit interaction from an adjacent TMD such as WS2 or WSe2 into graphene through wavefunction overlap, raising it by up to two orders of magnitude.

Proximity-induced superconductivity

Proximity-induced superconductivity is the induction of superconducting behavior in a non-superconducting material placed in electrical contact with a superconductor; it underlies Josephson junctions and weak links.

Proximus

Proximus is Belgium's largest telecommunications company, headquartered in Brussels and listed on Euronext Brussels. It descends from the state operator RTT, became Belgacom in 1992, and took the Proximus name in 2015.