All articles starting with P

Popular Unity (Chile)

Popular Unity (Unidad Popular) was the Chilean left-wing coalition formed in 1969 that elected Salvador Allende president in 1970 with 36.3% and governed until the September 11, 1973 military coup.

Popular Will (Voluntad Popular, VP) is a Venezuelan liberal-progressive, social-democratic opposition party founded in 2009 by Leopoldo López, presented in Valencia on 5 December 2009, registered in 2011, and central to the 2015 Assembly wins and 2019 Guaidó interim government.

Population (biology)

Population (biology): a group of interbreeding organisms of one species in a defined area, also called a biological population. Studied through size, density, exponential and logistic growth, carrying capacity, density dependence, demography, and genetic drift.

Population (human biology)

Population (human biology): a group of interbreeding humans sharing a gene pool; also called Mendelian population or deme. Defined by reproductive cohesion, effective size Ne governs drift, and it anchors human population biology.

Population 11

Population 11 is a 2024 Australian dark comedy crime thriller series (Stan, 14 March 2024, 12 episodes) starring Ben Feldman as an American searching for his vanished father in the outback town of Bidgeegud, loosely inspired by the 2017 Paddy Moriarty Larrimah disappearance.

Population ageing

Population ageing: rising share of older people in an age structure after the demographic dividend, driven mainly by falling fertility and longer lives; measured by 65+ share and old-age dependency ratios, with UN WPP 2024 projections.

Population balance model

A population balance model is a mathematical framework describing how populations of particles, droplets, or cells evolve under growth, nucleation, aggregation, and breakage, predicting particle size distributions.

Population bottleneck

Population bottleneck: a severe, temporary reduction in population size that erodes genetic diversity via drift. Key examples: the human out-of-Africa bottleneck ~70,000 years ago and the contested ~1-million-year FitCoal bottleneck; central to conservation genetics.

Population Characteristics

Population Characteristics is a MeSH descriptor (D011154, N01) covering demographic, health status, and socioeconomic qualities of populations, measured through censuses, vital statistics, surveys, and surveillance systems.

Population control

Wildlife population control limits overabundant animal populations using fertility control (PZP, GonaCon, diazacon, ContraPest) alongside lethal methods; used in deer, elephants, wild horses, and rats, with multi-year vaccines and delivery limits.

Population decline

Population decline: sustained fall in a country's or region's inhabitants. 63 countries including China, Japan, and Germany have peaked; UN projects global peak of 10.3 billion in the mid-2080s, then decline.

Population density

Population density is the number of people per unit of area, also measured as agricultural or physiological density. Key figures include a Vancouver health threshold near 9,400 per km² and density elasticities of wages and rents.

Population dynamics

Population dynamics is the study of how the size, structure, and distribution of populations change over time, a central branch of ecology built on mathematical models.

Population ecology

Population ecology is the branch of ecology that studies patterns in the abundance and distribution of single-species populations, and applies them to conservation and management.

Population exchange between Greece and Turkey

The population exchange between Greece and Turkey, agreed at Lausanne in 1923, forcibly transferred about 1.2 million Greek Orthodox Christians and 500,000 Muslims between the two countries.

Oct 22, 2026

Population exchange between Poland and Soviet Ukraine

The population exchange between Poland and Soviet Ukraine was a state-organized transfer agreed on 9 September 1944, moving Ukrainians from Poland and Poles from Ukraine.

Population genetics

Population genetics: study of allele and genotype frequency change in populations under mutation, selection, migration, and drift; Hardy-Weinberg equilibrium, effective population size (Wright), Fisher-Haldane-Wright theory, and human ancestry applications.

Population Groups

Population Groups is a Medical Subject Headings (MeSH) descriptor, maintained by the National Library of Medicine, covering people grouped by race, ethnicity, religion, residence, or social standing.

Population Growth

Population growth: increase over time in the number of people in a country or region, also called natural increase plus net migration. Global rate peaked at 2.3% in 1963; UN projects a peak near 10.3 billion in the mid-2080s.

Oct 20, 2026

Population Health

Population health: the health outcomes of a group of individuals and their distribution, per Kindig and Stoddart's 2003 definition; also called the population health approach, covering determinants, HALY/QALY/DALY measurement, and public health distinctions.

Population I

Population I, or Pop I, is the class of relatively young, metal-rich stars that inhabit the disks of spiral galaxies, including the Sun and most Milky Way disk stars.

Population II

Population II, or Pop II, stars are the old, metal-poor stars of a galaxy's bulge, halo, and globular clusters, formed early with 11 to 13 billion-year typical ages.

Population III

Population III (Pop III) stars are the hypothetical first stars, formed from metal-free primordial hydrogen and helium about 100 million years after the Big Bang.

Population III remnant seed

A Population III remnant seed is a stellar-mass black hole left by the death of one of the first stars, proposed as a seed of supermassive black holes.

Population inversion

Population inversion is a non-equilibrium condition in which an upper energy level holds more population per state than a lower one, enabling laser light amplification.

Population of Canada

Population of Canada: 41,798,407 estimated by Statistics Canada on July 1, 2026; grew 189,425 (+0.5%) year over year, the slowest since 1944/1945, driven almost entirely by international migration.

Population of Canada by province and territory

Canada's ten provinces and three territories held an estimated 41,798,407 people on July 1, 2026, up 0.46%, the slowest growth since 1946. Ontario holds 38.9% of the total.

Population pharmacokinetic analysis

Population pharmacokinetic analysis is a clinical pharmacology modeling method, originating with Lewis Sheiner's work in 1972, that estimates typical drug concentration profiles and variability across a population from sparse sampling data to guide dosing.

Population pharmacokinetic modeling

Population pharmacokinetic modeling is a pharmacometric method that fits nonlinear mixed-effects models to sparse clinical data, estimating typical drug concentration–time profiles, variability between patients, and supporting precision dosing.