All articles starting with P

Partial thromboplastin time

Partial thromboplastin time (PTT, aPTT) is a coagulation blood test measuring seconds to fibrin clot via the intrinsic pathway; normal about 25-37 seconds; used for hemophilia workup, heparin monitoring, and lupus anticoagulant detection.

Partial transmit sequence

Partial transmit sequence (PTS) is a distortionless technique for reducing the peak-to-average power ratio (PAPR) of OFDM signals, proposed by S.H. Müller and J.B. Huber in 1997.

Partial volume effect

The partial volume effect (PVE) is an imaging artifact in which a voxel contains more than one material, so its recorded value is an average of their properties.

Partial wave analysis

Partial wave analysis (PWA) is a scattering-theory method that decomposes reaction amplitudes into angular momentum components, extracting phase shifts, inelasticities, and resonance masses and widths from data.

Partial word

A partial word is a finite or infinite sequence over a finite alphabet in which some positions, called holes, are undefined; it extends ordinary words in combinatorics on words.

Partial-Birth Abortion Ban Act

The Partial-Birth Abortion Ban Act of 2003 (18 U.S.C. §1531), signed November 5, 2003, bans abortions in which a living fetus is partially vaginally delivered before a fatal overt act; Clinton vetoed 1996–97 versions, courts enjoined the 2003 act, and Gonzales v. Carhart (2007) upheld it.

Oct 21, 2026

Partially involuting congenital hemangioma

Partially involuting congenital hemangioma (PICH) is a rare benign vascular tumor fully formed at birth that regresses like a RICH but stops partway, leaving a NICH-like residual lesion; ulceration is its hallmark complication.

Partially observable Markov decision process

A partially observable Markov decision process (POMDP) is a mathematical model for sequential decision-making under uncertainty, where an agent acts on noisy observations and a belief state.

Partially ordered set

A partially ordered set, or poset, is a set with a reflexive, antisymmetric, transitive relation, so some elements rank relative to each other while others are unrelated.

Partially oriented yarn

Partially oriented yarn (POY), also called pre-oriented yarn, is a synthetic filament yarn, spun at high speed with incomplete orientation, used mainly to make draw textured yarn.

Partially stabilized zirconia

Partially stabilized zirconia is a zirconium dioxide ceramic whose metastable tetragonal phase gives transformation toughening, high strength, and high fracture toughness for industrial and dental uses.

Sep 19, 2026

Partiboi69

Partiboi69 is an Australian DJ and producer from Melbourne who plays ghetto house, Miami bass, and electro, known for green-screen visuals and narrative stage shows like Area69.

Sep 19, 2026

Partibrejkers

Partibrejkers (Партибрејкери) are a Serbian garage rock band formed in Belgrade in 1982, fronted by Zoran Kostić Cane and guitarist Nebojša Antonijević Anton; their bass-less 1985 debut is a landmark of Serbian rock.

Participant observation

Participant observation is a qualitative research method in which the researcher joins in the daily activities of the group being studied while keeping systematic records.

Participants in the Madoff investment scandal

The participants in the Madoff investment scandal were the employees, feeder funds, banks, and regulators involved in Bernard Madoff's Ponzi scheme, which cost customers about $17.3 billion.

Participating nations at the Winter Universiade by edition

This article lists how many nations and athletes took part in each Winter Universiade, from 15 countries in 1960 to a record 58 in 2019.

Participation criterion

Participation criterion: a social choice theory axiom requiring that adding voters who prefer candidate x to y cannot change the winner from x to y; linked to the no show paradox and Moulin's 1988 impossibility theorem.

Participation of nations at the Summer Paralympic Games

National participation at the Summer Paralympic Games, via National Paralympic Committees: grew from 21 countries at Rome 1960 to a record 169 delegations at Paris 2024, plus refugee and neutral athlete entries.

Participatory action research

Participatory action research (PAR) is a collaborative social-science method in which researchers and community members jointly investigate problems and act on findings, aiming for social change.

Participatory budgeting

Participatory budgeting (PB) is a democratic process in which community members decide how to spend part of a public budget, begun in Porto Alegre, Brazil, in 1989.

Participatory democracy

Participatory democracy: a democratic model where citizens actively shape public decisions beyond voting. Distinguished from deliberative democracy; rooted in 1960s activism; includes practices like Porto Alegre's 1989 participatory budgeting and OECD-tracked deliberative processes.

Participatory evaluation

Participatory evaluation is an approach to evaluating programs and policies in which stakeholders such as staff, participants, and community members share control over the process.

Participatory GIS

Participatory GIS (PGIS) is a social-science research method in which community members collaboratively create and analyze GIS maps, so local spatial knowledge enters planning, research, and advocacy.

Participatory learning and action

Participatory learning and action (PLA) is a family of qualitative research approaches in which community members, rather than outside experts, analyze their own situation and act on it.

Participatory mapping

Participatory mapping is a research and planning method in which community members collaboratively create maps documenting local knowledge, resources, and land use, from sketch maps to GPS-based digital maps.

Participatory modeling

Participatory modeling is a transdisciplinary approach in which stakeholders help build and use models of a system, clarifying the impacts of solutions for decision making and management.

Participatory rural appraisal

Participatory rural appraisal (PRA) is a family of qualitative research methods in which rural community members, facilitated by outsiders, map and analyze their own knowledge to plan and act.

Participatory sensing

Participatory sensing is a data collection method in mobile computing, introduced in 2006, in which volunteers use mobile phones to gather and share local environmental measurements.

Participle

Participle: a non-finite verb form used as an adjective or in verb phrases. English has a present participle in -ing (carrying) and a past participle in -ed/-en (bought, hidden); Latin has three, Russian four, and typologists define participles as verb forms used for adnominal modification.