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23619 | https://en.wikipedia.org/wiki/Pressure | Pressure | Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled gage pressure) is the pressure relative to the ambient pressure.
Various units are used to express pressure. Some of these derive from a unit of forc... | Physical sciences | Thermodynamics | null |
23621 | https://en.wikipedia.org/wiki/Polygon | Polygon | In geometry, a polygon () is a plane figure made up of line segments connected to form a closed polygonal chain.
The segments of a closed polygonal chain are called its edges or sides. The points where two edges meet are the polygon's vertices or corners. An n-gon is a polygon with n sides; for example, a triangle is ... | Mathematics | Geometry and topology | null |
23631 | https://en.wikipedia.org/wiki/Primary%20mirror | Primary mirror | A primary mirror (or primary) is the principal light-gathering surface (the objective) of a reflecting telescope.
Description
The primary mirror of a reflecting telescope is a spherical, parabolic, or hyperbolic shaped disks of polished reflective metal (speculum metal up to the mid 19th century), or in later telescop... | Technology | Telescope | null |
23634 | https://en.wikipedia.org/wiki/Protein | Protein | Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting mol... | Biology and health sciences | Chemistry | null |
23635 | https://en.wikipedia.org/wiki/Physical%20chemistry | Physical chemistry | Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics, analytical dynamics and chemical equilibria.
Physical chemistry, in ... | Physical sciences | Chemistry | null |
23636 | https://en.wikipedia.org/wiki/Perimeter | Perimeter | A perimeter is a closed path that encompasses, surrounds, or outlines either a two dimensional shape or a one-dimensional length. The perimeter of a circle or an ellipse is called its circumference.
Calculating the perimeter has several practical applications. A calculated perimeter is the length of fence required to ... | Mathematics | Measurement | null |
23637 | https://en.wikipedia.org/wiki/Phase%20%28matter%29 | Phase (matter) | In the physical sciences, a phase is a region of material that is chemically uniform, physically distinct, and (often) mechanically separable. In a system consisting of ice and water in a glass jar, the ice cubes are one phase, the water is a second phase, and the humid air is a third phase over the ice and water. The ... | Physical sciences | Phase transitions | null |
23639 | https://en.wikipedia.org/wiki/Gasoline | Gasoline | Gasoline (North American English) or petrol (Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When formulated as a fuel for engines, gasoline is chemically composed of organic compounds... | Technology | Energy and fuel | null |
23643 | https://en.wikipedia.org/wiki/Propane | Propane | Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is often a constituent of liquefied petroleum gas (LPG), which is commonly used as a fuel in do... | Physical sciences | Hydrocarbons | null |
23645 | https://en.wikipedia.org/wiki/Precambrian | Precambrian | The Precambrian ( ; or Pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinized name for Wales... | Physical sciences | Geological periods | null |
23647 | https://en.wikipedia.org/wiki/Polymerase%20chain%20reaction | Polymerase chain reaction | The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed study. PCR was invented in 1983 by American biochemist Kary Mullis at Cetus Cor... | Technology | Biotechnology | null |
23652 | https://en.wikipedia.org/wiki/Purine | Purine | Purine is a heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers. They are the most widely occurring nitrogen-containing... | Physical sciences | Alkaloids | Chemistry |
23653 | https://en.wikipedia.org/wiki/Pyrimidine | Pyrimidine | Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring. The other diazines are pyrazine (nitrogen atoms at the 1 and 4 positions) and pyridaz... | Physical sciences | Alkaloids | Chemistry |
23659 | https://en.wikipedia.org/wiki/Plug-in%20%28computing%29 | Plug-in (computing) | In computing, a plug-in (or plugin, add-in, addin, add-on, or addon) is a software component that extends the functionality of an existing software system without requiring the system to be re-built. A plug-in feature is one way that a system can be customizable.
Applications support plug-ins for a variety of reasons ... | Technology | Computer software | null |
23664 | https://en.wikipedia.org/wiki/Papyrus | Papyrus | Papyrus ( ) is a material similar to thick paper that was used in ancient times as a writing surface. It was made from the pith of the papyrus plant, Cyperus papyrus, a wetland sedge. Papyrus (plural: papyri or papyruses) can also refer to a document written on sheets of such material, joined side by side and rolled up... | Technology | Material and chemical | null |
23665 | https://en.wikipedia.org/wiki/Pixel | Pixel | In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, pixels are the smallest element that can be manipulated through software.
Each pixel is a sa... | Technology | Computer science | null |
23666 | https://en.wikipedia.org/wiki/Prime%20number | Prime number | A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, or , involve 5 itself. However, 4 is composite b... | Mathematics | Counting and numbers | null |
23670 | https://en.wikipedia.org/wiki/Perfect%20number | Perfect number | In number theory, a perfect number is a positive integer that is equal to the sum of its positive proper divisors, that is, divisors excluding the number itself. For instance, 6 has proper divisors 1, 2 and 3, and 1 + 2 + 3 = 6, so 6 is a perfect number. The next perfect number is 28, since 1 + 2 + 4 + 7 + 14 = 28.
Th... | Mathematics | Sums and products | null |
23690 | https://en.wikipedia.org/wiki/Phosphate | Phosphate | In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid, phosphoric acid .
The phosphate or orthophosphate ion is derived from phosphoric acid by the removal of three protons . Removal of one ... | Physical sciences | Phosphoric oxyanions | Chemistry |
23692 | https://en.wikipedia.org/wiki/Prime%20number%20theorem | Prime number theorem | In mathematics, the prime number theorem (PNT) describes the asymptotic distribution of the prime numbers among the positive integers. It formalizes the intuitive idea that primes become less common as they become larger by precisely quantifying the rate at which this occurs. The theorem was proved independently by Ja... | Mathematics | Other | null |
23703 | https://en.wikipedia.org/wiki/Potential%20energy | Potential energy | In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. The term potential energy was introduced by the 19th-century Scottish engineer and physicist William Rankine, although it has links to the ancien... | Physical sciences | Classical mechanics | null |
23704 | https://en.wikipedia.org/wiki/Pyramid | Pyramid | A pyramid () is a structure whose visible surfaces are triangular in broad outline and converge toward the top, making the appearance roughly a pyramid in the geometric sense. The base of a pyramid can be of any polygon shape, such as triangular or quadrilateral, and its lines either filled or stepped.
A pyramid has t... | Technology | Ceremonial buildings | null |
23738 | https://en.wikipedia.org/wiki/Propeller | Propeller | A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. Propellers are used to pump fluid through a pipe o... | Technology | Rigid components | null |
23740 | https://en.wikipedia.org/wiki/Toxin | Toxin | A toxin is a naturally occurring poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived from toxic.
Toxins can be small molecules, peptides, or proteins that are capable of... | Biology and health sciences | Types | Health |
23743 | https://en.wikipedia.org/wiki/Phanerozoic | Phanerozoic | The Phanerozoic is the current and the latest of the four geologic eons in the Earth's geologic time scale, covering the time period from 538.8 million years ago to the present. It is the eon during which abundant animal and plant life has proliferated, diversified and colonized various niches on the Earth's surface, b... | Physical sciences | Geological periods | null |
23747 | https://en.wikipedia.org/wiki/Peroxide | Peroxide | In chemistry, peroxides are a group of compounds with the structure , where the R's represent a radical (a portion of a complete molecule; not necessarily a free radical) and O's are single oxygen atoms. Oxygen atoms are joined to each other and to adjacent elements through single covalent bonds, denoted by dashes or l... | Physical sciences | Peroxide salts | Chemistry |
23749 | https://en.wikipedia.org/wiki/Platypus | Platypus | The platypus (Ornithorhynchus anatinus), sometimes referred to as the duck-billed platypus, is a semiaquatic, egg-laying mammal endemic to eastern Australia, including Tasmania. The platypus is the sole living representative or monotypic taxon of its family Ornithorhynchidae and genus Ornithorhynchus, though a number o... | Biology and health sciences | Monotremes | null |
23750 | https://en.wikipedia.org/wiki/Paramagnetism | Paramagnetism | Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, diamagnetic materials are repelled by magnetic fields and form induced magn... | Physical sciences | Magnetostatics | Physics |
23773 | https://en.wikipedia.org/wiki/Pascal%20%28programming%20language%29 | Pascal (programming language) | Pascal is an imperative and procedural programming language, designed by Niklaus Wirth as a small, efficient language intended to encourage good programming practices using structured programming and data structuring. It is named after French mathematician, philosopher and physicist Blaise Pascal.
Pascal was developed... | Technology | "Historical" languages | null |
23776 | https://en.wikipedia.org/wiki/Paint | Paint | Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are either oil-based or water-based, and each has distinct characteristics.
P... | Technology | Artist's tools | null |
23798 | https://en.wikipedia.org/wiki/Poincar%C3%A9%20conjecture | Poincaré conjecture | In the mathematical field of geometric topology, the Poincaré conjecture (, , ) is a theorem about the characterization of the 3-sphere, which is the hypersphere that bounds the unit ball in four-dimensional space.
Originally conjectured by Henri Poincaré in 1904, the theorem concerns spaces that locally look like ord... | Mathematics | Geometry | null |
23799 | https://en.wikipedia.org/wiki/Power%20set | Power set | In mathematics, the power set (or powerset) of a set is the set of all subsets of , including the empty set and itself. In axiomatic set theory (as developed, for example, in the ZFC axioms), the existence of the power set of any set is postulated by the axiom of power set.
The powerset of is variously denoted as ,... | Mathematics | Set theory | null |
23842 | https://en.wikipedia.org/wiki/Planets%20beyond%20Neptune | Planets beyond Neptune | Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. The search began in the mid-19th century and continued at the start of the 20th with Percival Lowell's quest for Planet X. Lowell proposed the Planet X hypothesis to explain appare... | Physical sciences | Solar System | Astronomy |
23862 | https://en.wikipedia.org/wiki/Python%20%28programming%20language%29 | Python (programming language) | Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation.
Python is dynamically type-checked and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented ... | Technology | Scripting languages | null |
23863 | https://en.wikipedia.org/wiki/Pyridine | Pyridine | Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom . It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish-like smell. Pyridine is colorless, but older or... | Physical sciences | Amides and amines | Chemistry |
23872 | https://en.wikipedia.org/wiki/Polymerization | Polymerization | In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many forms of polymerization and different systems exist to categorize them.
In chemi... | Physical sciences | Organic reactions | Chemistry |
23878 | https://en.wikipedia.org/wiki/Penguin | Penguin | Penguins are a group of aquatic flightless birds from the family Spheniscidae () of the order Sphenisciformes (). They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adapted for life in the ocean water, penguins have countershaded dark ... | Biology and health sciences | Sphenisciformes | null |
23889 | https://en.wikipedia.org/wiki/Pulley | Pulley | A pulley is a wheel on an axle or shaft enabling a taut cable or belt passing over the wheel to move and change direction, or transfer power between itself and a shaft. A sheave or pulley wheel is a pulley using an axle supported by a frame or shell (block) to guide a cable or exert force.
A pulley may have a groove o... | Technology | Basics_8 | null |
23905 | https://en.wikipedia.org/wiki/Platonic%20solid | Platonic solid | In geometry, a Platonic solid is a convex, regular polyhedron in three-dimensional Euclidean space. Being a regular polyhedron means that the faces are congruent (identical in shape and size) regular polygons (all angles congruent and all edges congruent), and the same number of faces meet at each vertex. There are onl... | Mathematics | Three-dimensional space | null |
23924 | https://en.wikipedia.org/wiki/Passenger%20pigeon | Passenger pigeon | The passenger pigeon or wild pigeon (Ectopistes migratorius) is an extinct species of pigeon that was endemic to North America. Its common name is derived from the French word passager, meaning "passing by", due to the migratory habits of the species. The scientific name also refers to its migratory characteristics. Th... | Biology and health sciences | Columbiformes | null |
23939 | https://en.wikipedia.org/wiki/Perl | Perl | Perl is a high-level, general-purpose, interpreted, dynamic programming language. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language".
Perl was developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report ... | Technology | Scripting languages | null |
23962 | https://en.wikipedia.org/wiki/Phylogenetics | Phylogenetics | In biology, phylogenetics () is the study of the evolutionary history of life using genetics, which is known as phylogenetic inference. It establishes the relationship between organisms with the empirical data and observed heritable traits of DNA sequences, protein amino acid sequences, and morphology. The results are ... | Biology and health sciences | Genetics and taxonomy | null |
23971 | https://en.wikipedia.org/wiki/Pilus | Pilus | A pilus (Latin for 'hair'; : pili) is a hair-like cell-surface appendage found on many bacteria and archaea. The terms pilus and fimbria (Latin for 'fringe'; plural: fimbriae) can be used interchangeably, although some researchers reserve the term pilus for the appendage required for bacterial conjugation. All conjug... | Biology and health sciences | Basic anatomy | Biology |
23974 | https://en.wikipedia.org/wiki/Plasmid | Plasmid | A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; however, plasmids are sometimes present in archaea and eukaryotic organisms. Pla... | Biology and health sciences | Cellular division | null |
23977 | https://en.wikipedia.org/wiki/Plant%20cell | Plant cell | Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regula... | Biology and health sciences | Plant cells | null |
23978 | https://en.wikipedia.org/wiki/Polysaccharide | Polysaccharide | Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with water (hydrolysis) using amylase enzymes as catalyst, which produces constitue... | Biology and health sciences | Carbohydrates | Biology |
23984 | https://en.wikipedia.org/wiki/Pyxis | Pyxis | Pyxis is a small and faint constellation in the southern sky. Abbreviated from Pyxis Nautica, its name is Latin for a mariner's compass (contrasting with Circinus, which represents a draftsman's compasses). Pyxis was introduced by Nicolas-Louis de Lacaille in the 18th century, and is counted among the 88 modern constel... | Physical sciences | Other | Astronomy |
23990 | https://en.wikipedia.org/wiki/Puppis | Puppis | Puppis ("stern") is a constellation in the southern sky. It was originally part of the traditional constellation of Argo Navis (the ship of Jason and the Argonauts), which was divided into three parts, the other two being Carina (the keel and hull), and Vela (the sails). Puppis is the largest of the three constellation... | Physical sciences | Other | Astronomy |
23992 | https://en.wikipedia.org/wiki/Piscis%20Austrinus | Piscis Austrinus | Piscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish", in contrast with the larger constellation Pisces, which represents a pair of fish. Before the 20th century, it was also known as Piscis Notius. Piscis Austrinus was one of the 48 constellations listed by... | Physical sciences | Other | Astronomy |
24006 | https://en.wikipedia.org/wiki/Paraffin%20wax | Paraffin wax | Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum, coal, or oil shale that consists of a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and begins to melt above approximately , and its boiling point is above . Common application... | Physical sciences | Hydrocarbons | Chemistry |
24007 | https://en.wikipedia.org/wiki/Pearl | Pearl | A pearl is a hard, glistening object produced within the soft tissue (specifically the mantle) of a living shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pearl is composed of calcium carbonate (mainly aragonite or a mixture of aragonite and calcite) in minute crystal... | Physical sciences | Organic gemstones | null |
24022 | https://en.wikipedia.org/wiki/Physical%20therapy | Physical therapy | Physical therapy (PT), also known as physiotherapy, is a healthcare profession, as well as the care provided by physical therapists who promote, maintain, or restore health through patient education, physical intervention, disease prevention, and health promotion. Physical therapist is the term used for such profession... | Biology and health sciences | Medical procedures | null |
24026 | https://en.wikipedia.org/wiki/Proteome | Proteome | A proteome is the entire set of proteins that is, or can be, expressed by a genome, cell, tissue, or organism at a certain time. It is the set of expressed proteins in a given type of cell or organism, at a given time, under defined conditions. Proteomics is the study of the proteome.
Types of proteomes
While proteome... | Biology and health sciences | Proteins | Biology |
24029 | https://en.wikipedia.org/wiki/Peptide | Peptide | Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and ... | Biology and health sciences | Proteins | Biology |
24032 | https://en.wikipedia.org/wiki/Positron%20emission%20tomography | Positron emission tomography | Positron emission tomography (PET) is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption. Different tracers are used for v... | Technology | Imaging | null |
24047 | https://en.wikipedia.org/wiki/Phase%20%28waves%29 | Phase (waves) | In physics and mathematics, the phase (symbol φ or ϕ) of a wave or other periodic function of some real variable (such as time) is an angle-like quantity representing the fraction of the cycle covered up to . It is expressed in such a scale that it varies by one full turn as the variable goes through each period (a... | Physical sciences | Waves | Physics |
24048 | https://en.wikipedia.org/wiki/Particle%20in%20a%20box | Particle in a box | In quantum mechanics, the particle in a box model (also known as the infinite potential well or the infinite square well) describes the movement of a free particle in a small space surrounded by impenetrable barriers. The model is mainly used as a hypothetical example to illustrate the differences between classical an... | Physical sciences | Quantum mechanics | Physics |
24062 | https://en.wikipedia.org/wiki/Peroxisome | Peroxisome | A peroxisome () is a membrane-bound organelle, a type of microbody, found in the cytoplasm of virtually all eukaryotic cells. Peroxisomes are oxidative organelles. Frequently, molecular oxygen serves as a co-substrate, from which hydrogen peroxide (H2O2) is then formed. Peroxisomes owe their name to hydrogen peroxide g... | Biology and health sciences | Organelles | Biology |
24075 | https://en.wikipedia.org/wiki/Peripheral%20Component%20Interconnect | Peripheral Component Interconnect | Peripheral Component Interconnect (PCI) is a local computer bus for attaching hardware devices in a computer and is part of the PCI Local Bus standard. The PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any given processor's native bus. Devices connected to t... | Technology | Computer hardware | null |
24077 | https://en.wikipedia.org/wiki/PDF | PDF | Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. Based on the PostScript language, each PDF file encapsulates a complete des... | Technology | File formats | null |
24085 | https://en.wikipedia.org/wiki/Phenol | Phenol | Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it requires careful handling because it can cause chemic... | Physical sciences | Carbon–oxygen bond | null |
24096 | https://en.wikipedia.org/wiki/Plough | Plough | A plough or (US) plow (both pronounced ) is a farm tool for loosening or turning the soil before sowing seed or planting. Ploughs were traditionally drawn by oxen and horses but modern ploughs are drawn by tractors. A plough may have a wooden, iron or steel frame with a blade attached to cut and loosen the soil. It has... | Technology | Agricultural tools | null |
24107 | https://en.wikipedia.org/wiki/Peer-to-peer | Peer-to-peer | Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the network, forming a peer-to-peer network of nodes. In addition, a personal area network (PAN) is also in nature a type of dec... | Technology | Internet | null |
24116 | https://en.wikipedia.org/wiki/Peer%20review | Peer review | Peer review is the evaluation of work by one or more people with similar competencies as the producers of the work (peers). It functions as a form of self-regulation by qualified members of a profession within the relevant field. Peer review methods are used to maintain quality standards, improve performance, and provi... | Physical sciences | Science basics | Basics and measurement |
24130 | https://en.wikipedia.org/wiki/Energy%20storage | Energy storage | Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in multiple forms including radiation, chemical, gravitational potential, electri... | Technology | Energy storage | null |
24131 | https://en.wikipedia.org/wiki/PHP | PHP | PHP is a general-purpose scripting language geared towards web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1993 and released in 1995. The PHP reference implementation is now produced by the PHP Group. PHP was originally an abbreviation of Personal Home Page, but it now stands ... | Technology | Scripting languages | null |
24138 | https://en.wikipedia.org/wiki/Proton%20decay | Proton decay | In particle physics, proton decay is a hypothetical form of particle decay in which the proton decays into lighter subatomic particles, such as a neutral pion and a positron. The proton decay hypothesis was first formulated by Andrei Sakharov in 1967. Despite significant experimental effort, proton decay has never bee... | Physical sciences | Particle physics: General | Physics |
24151 | https://en.wikipedia.org/wiki/Flatworm | Flatworm | Platyhelminthes (from the Greek πλατύ, platy, meaning "flat" and ἕλμινς (root: ἑλμινθ-), helminth-, meaning "worm") is a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates commonly called flatworms or flat worms. Being acoelomates (having no body cavity), and having no specialised circulator... | Biology and health sciences | Platyzoa | null |
24160 | https://en.wikipedia.org/wiki/Piper%20%28plant%29 | Piper (plant) | Piper, the pepper plants or pepper vines, is an economically and ecologically important genus in the family Piperaceae.
It contains about 1,000–2,000 species of shrubs, herbs, and lianas, many of which are dominant species in their native habitat. The diversification of this taxon is of interest to understanding the e... | Biology and health sciences | Piperales | Plants |
24222 | https://en.wikipedia.org/wiki/Public-key%20cryptography | Public-key cryptography | Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys. Each key pair consists of a public key and a corresponding private key. Key pairs are generated with cryptographic algorithms based on mathematical problems termed one-way functions. Security of pu... | Technology | Computer security | null |
24236 | https://en.wikipedia.org/wiki/Power%20%28physics%29 | Power (physics) | Power is the amount of energy transferred or converted per unit time. In the International System of Units, the unit of power is the watt, equal to one joule per second. Power is a scalar quantity.
Specifying power in particular systems may require attention to other quantities; for example, the power involved in movi... | Physical sciences | Classical mechanics | null |
24241 | https://en.wikipedia.org/wiki/Protoscience | Protoscience | In the philosophy of science, protoscience is a research field that has the characteristics of an undeveloped science that may ultimately develop into an established science. Philosophers use protoscience to understand the history of science and distinguish protoscience from science and pseudoscience. The word “proto... | Physical sciences | Science basics | Basics and measurement |
24255 | https://en.wikipedia.org/wiki/Pandemic | Pandemic | A pandemic ( ) is an epidemic of an infectious disease that has a sudden increase in cases and spreads across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals. Widespread endemic diseases with a stable number of infected individuals such as recurrences of seas... | Biology and health sciences | Concepts | Health |
24278 | https://en.wikipedia.org/wiki/Pear | Pear | Pears are fruits produced and consumed around the world, growing on a tree and harvested in late summer into mid-autumn. The pear tree and shrub are a species of genus Pyrus , in the family Rosaceae, bearing the pomaceous fruit of the same name. Several species of pears are valued for their edible fruit and juices, whi... | Biology and health sciences | Rosales | null |
24304 | https://en.wikipedia.org/wiki/Password | Password | A password, sometimes called a passcode, is secret data, typically a string of characters, usually used to confirm a user's identity. Traditionally, passwords were expected to be memorized, but the large number of password-protected services that a typical individual accesses can make memorization of unique passwords f... | Technology | Computer security | null |
24306 | https://en.wikipedia.org/wiki/PNG | PNG | Portable Network Graphics (PNG, officially pronounced , colloquially pronounced ) is a raster-graphics file format that supports lossless data compression. PNG was developed as an improved, non-patented replacement for Graphics Interchange Format (GIF)—unofficially, the initials PNG stood for the recursive acronym "P... | Technology | File formats | null |
24314 | https://en.wikipedia.org/wiki/Planar%20graph | Planar graph | In graph theory, a planar graph is a graph that can be embedded in the plane, i.e., it can be drawn on the plane in such a way that its edges intersect only at their endpoints. In other words, it can be drawn in such a way that no edges cross each other. Such a drawing is called a plane graph, or a planar embedding ... | Mathematics | Graph theory | null |
24327 | https://en.wikipedia.org/wiki/Prairie%20dog | Prairie dog | Prairie dogs (genus Cynomys) are herbivorous burrowing ground squirrels native to the grasslands of North America. There are five recognized species of prairie dog: black-tailed, white-tailed, Gunnison's, Utah, and Mexican prairie dogs. In Mexico, prairie dogs are found primarily in the northern states, which lie at th... | Biology and health sciences | Rodents | Animals |
24330 | https://en.wikipedia.org/wiki/Porcupinefish | Porcupinefish | Porcupinefish are medium-to-large fish belonging to the family Diodontidae from the order Tetraodontiformes which are also commonly called blowfish and, sometimes, balloonfish and globefish. The family includes about 18 species. They are sometimes collectively called pufferfish, not to be confused with the morphologica... | Biology and health sciences | Acanthomorpha | Animals |
24350 | https://en.wikipedia.org/wiki/Projective%20plane | Projective plane | In mathematics, a projective plane is a geometric structure that extends the concept of a plane. In the ordinary Euclidean plane, two lines typically intersect at a single point, but there are some pairs of lines (namely, parallel lines) that do not intersect. A projective plane can be thought of as an ordinary plane e... | Mathematics | Non-Euclidean geometry | null |
24354 | https://en.wikipedia.org/wiki/Pharmacology | Pharmacology | Pharmacology is the science of drugs and medications, including a substance's origin, composition, pharmacokinetics, pharmacodynamics, therapeutic use, and toxicology. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical fun... | Biology and health sciences | Drugs and pharmacology | null |
24373 | https://en.wikipedia.org/wiki/Pain | Pain | Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage."
Pain motivates organisms to withdraw fr... | Biology and health sciences | Nervous system | null |
24408 | https://en.wikipedia.org/wiki/Polar%20bear | Polar bear | The polar bear (Ursus maritimus) is a large bear native to the Arctic and nearby areas. It is closely related to the brown bear, and the two species can interbreed. The polar bear is the largest extant species of bear and land carnivore, with adult males weighing . The species is sexually dimorphic, as adult females ar... | Biology and health sciences | Carnivora | null |
24420 | https://en.wikipedia.org/wiki/Punched%20card | Punched card | A punched card (also punch card or punched-card) is a piece of card stock that stores digital data using punched holes. Punched cards were once common in data processing and the control of automated machines.
Punched cards were widely used in the 20th century, where unit record machines, organized into data processing... | Technology | Data storage | null |
24438 | https://en.wikipedia.org/wiki/PAL | PAL | Phase Alternating Line (PAL) is a colour encoding system for analog television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 frames) per second, and associated with CCIR analogue broadcast television syste... | Technology | Broadcasting | null |
24458 | https://en.wikipedia.org/wiki/Polyvinyl%20chloride | Polyvinyl chloride | Polyvinyl chloride (alternatively: poly(vinyl chloride), colloquial: vinyl or polyvinyl; abbreviated: PVC) is the world's third-most widely produced synthetic polymer of plastic (after polyethylene and polypropylene). About 40 million tons of PVC are produced each year.
PVC comes in rigid (sometimes abbreviated as RPV... | Physical sciences | Salts | null |
24471 | https://en.wikipedia.org/wiki/Phonograph | Phonograph | A phonograph, later called a gramophone (as a trademark since 1887, as a generic name in the UK since 1910), and since the 1940s a record player, or more recently a turntable, is a device for the mechanical and analogue reproduction of sound. The sound vibration waveforms are recorded as corresponding physical deviatio... | Technology | Media and communication: Basics | null |
24489 | https://en.wikipedia.org/wiki/Outline%20of%20physics | Outline of physics | The following outline is provided as an overview of and topical guide to physics:
Physics – natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how ... | Physical sciences | Physics basics: General | Physics |
24505 | https://en.wikipedia.org/wiki/Phospholipid | Phospholipid | Phospholipids are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typically have omega-3 fatty acids EPA and DHA integrated as part of the phospho... | Biology and health sciences | Lipids | Biology |
24508 | https://en.wikipedia.org/wiki/Pencil | Pencil | A pencil () is a writing or drawing implement with a solid pigment core in a protective casing that reduces the risk of core breakage and keeps it from marking the user's hand.
Pencils create marks by physical abrasion, leaving a trail of solid core material that adheres to a sheet of paper or other surface. They are ... | Technology | Artist's tools | null |
24510 | https://en.wikipedia.org/wiki/Pushdown%20automaton | Pushdown automaton | In the theory of computation, a branch of theoretical computer science, a pushdown automaton (PDA) is
a type of automaton that employs a stack.
Pushdown automata are used in theories about what can be computed by machines. They are more capable than finite-state machines but less capable than Turing machines (see b... | Mathematics | Automata theory | null |
24514 | https://en.wikipedia.org/wiki/Psychosis | Psychosis | Psychosis is a condition of the mind or psyche that results in difficulties determining what is real and what is not real. Symptoms may include delusions and hallucinations, among other features. Additional symptoms are disorganized thinking and incoherent speech and behavior that is inappropriate for a given situatio... | Biology and health sciences | Miscellaneous | null |
24515 | https://en.wikipedia.org/wiki/Paranoia | Paranoia | Paranoia is an instinct or thought process that is believed to be heavily influenced by anxiety, suspicion, or fear, often to the point of delusion and irrationality. Paranoid thinking typically includes persecutory beliefs, or beliefs of conspiracy concerning a perceived threat towards oneself (i.e., "Everyone is out ... | Biology and health sciences | Mental disorders | Health |
24530 | https://en.wikipedia.org/wiki/PH | PH | In chemistry, pH ( ), also referred to as acidity or basicity, historically denotes "potential of hydrogen" (or "power of hydrogen"). It is a logarithmic scale used to specify the acidity or basicity of aqueous solutions. Acidic solutions (solutions with higher concentrations of hydrogen () ions) are measured to have l... | Physical sciences | Chemistry: General | null |
24533 | https://en.wikipedia.org/wiki/Pastel | Pastel | A pastel () is an art medium that consist of powdered pigment and a binder. It can exist in a variety of forms, including a stick, a square, a pebble, and a pan of color, among other forms. The pigments used in pastels are similar to those used to produce some other colored visual arts media, such as oil paints; the bi... | Technology | Artist's tools | null |
24543 | https://en.wikipedia.org/wiki/Phenotype | Phenotype | In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results... | Biology and health sciences | Genetics | Biology |
24544 | https://en.wikipedia.org/wiki/Photosynthesis | Photosynthesis | Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism.
Photosynthesis usually refers to oxygenic photosynthesis, a process that p... | Biology and health sciences | Biology | null |
24553 | https://en.wikipedia.org/wiki/Protein%20biosynthesis | Protein biosynthesis | Protein biosynthesis (or protein synthesis) is a core biological process, occurring inside cells, balancing the loss of cellular proteins (via degradation or export) through the production of new proteins. Proteins perform a number of critical functions as enzymes, structural proteins or hormones. Protein synthesis is ... | Biology and health sciences | Proteins | Biology |
24579 | https://en.wikipedia.org/wiki/Pelvic%20inflammatory%20disease | Pelvic inflammatory disease | Pelvic inflammatory disease, also known as pelvic inflammatory disorder (PID), is an infection of the upper part of the female reproductive system, mainly the uterus, fallopian tubes, and ovaries, and inside of the pelvis. Often, there may be no symptoms. Signs and symptoms, when present, may include lower abdominal pa... | Biology and health sciences | Infectious diseases by site | Health |
24598 | https://en.wikipedia.org/wiki/Pointing%20device | Pointing device | A pointing device is a human interface device that allows a user to input spatial (i.e., continuous and multi-dimensional) data to a computer. Graphical user interfaces (GUI) and CAD systems allow the user to control and provide data to the computer using physical gestures by moving a hand-held mouse or similar device ... | Technology | User interface | null |
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