Encyclopedia

Physical optics In physics, physical optics, or wave optics, is the branch of optics which studies interference, diffraction, polarization, and other phenomena for which the ray approximation of geometric optics is not valid. This usage tends not to include effects such as quantum noise in optical communication, which is studied in the sub-branch of coherence theory.
Physical paradox A physical paradox is an apparent contradiction relating to physical descriptions of the universe. As such, there are many different uses for the term ranging from a challenging thought experiment that seems to belie common sense to an actual breakdown of the mathematical theory that describes the physical universe.
Physical phenomenon A physical phenomenon is a phenomenon that is describable by physics and involved with some form of matter, energy, or spacetime. Physical phenomena are usually regarded as, at least in theory, subjects of observation - Niels Bohr, one of the fathers of quantum mechanics, is quoted with saying "no phenomenon is a phenomenon until it is an observed phenomenon.
Physical plane The physical plane, physical world, or physical universe in Hermeticism, Theosophical, Rosicrucian and New Age thought refers to the visible reality of space and time, energy and matter. In contrast to Western secular modernist and postmodern thought, the physical universe is in occult and esoteric cosmology only the lowest or densest of a whole series of planes of existence.
Physical plant A physical plant or mechanical plant refers to the necessary infrastructure used in support of a given facility. The operation of these facilities, or the department of an organization which does so, is called plant operations.
Physical quality Physical quantities are well understood in physics, and it is common today to see physical theories as connecting physical quantities. In fact, physical quantities can be seen as coordinates over abstract manifolds, the spaces of physical qualities.
Physical quality-of-life index The physical quality-of-life index (PQLI) is an attempt to measure the quality of life or well-being of a country. The value is a single number derived from basic literacy rate, infant mortality, and life expectancy at age one, all equally weighted on a 0 to 100 scale.
Physical restraint Physical restraint refers to the practice of rendering people helpless or keeping them in captivity by means such as handcuffs, shackles, straitjackets, ropes, straps, ball locks or other forms of physical restraint. Alternatively, unarmed combat techniques or sheer force of numbers may be used to restrain a person.
Physical Readiness Test A Physical Readiness Test is conducted by United States military organizations to determine the physical fitness of an ensign. There are multiple scoring ranges including (from lowest to highest): satisfactory, good, excellent, and outstanding with low, medium and high in each category.
Physical Research Laboratory The Physical Research Laboratory is a national centre for research in space and allied sciences, supported mainly by Department of Space. This research laboratory currently has ongoing research programmes over astronomy and astrophysics, planetary atmosphere and aeronomy, earth sciences, solar system studies and theoretical physics.
Physical Review Focus Physical Review Focus is an internet service of the American Physical Society, aiming to explain new developments in physics in a language understandable to the educated non-physicist. One or two short articles are published weekly.
Physical science Physical Science is an encompassing term for the branches of natural science, and science (generally), that study non-living systems, in contrast to the biological sciences. However, the term "physical" creates an unintended, somewhat arbitrary distinction, since many branches of physical science also study biological phenomena.
Physical security Physical security describes measures that prevent or deter attackers from accessing a facility, resource, or information stored on physical media. It can be as simple as a locked door or as elaborate as multiple layers of armed guardposts.
Physical system A physical system is a system that is comprised of matter and energy, which we can learn about using the tools of physics. In this context, a "system" is taken to mean "an interrelated, interworking set of objects that operates independently".
Physical theatre Physical theatre is a general term used to describe any mode of performance that pursues storytelling through primarily physical means. There are several quite distinct traditions of performance which all describe themselves using the term "physical theatre", which has led to a lot of confusion as to what the definition of physical theatre actually is.
Physical therapy Physical therapy (or physiotherapy*) is the provision of services to people and populations to develop, maintain and restore maximum movement and functional ability throughout the lifespan. It includes the provision of services in circumstances where movement and function are threatened by the process of ageing or that of injury or disease.
Physical training uniform The physical training uniform is a military uniform used during calisthenics drills and, in some cases, very casual periods of time (off-duty time during Initial Entry Training in the Army, for example). The United States Army and Navy and US Air Force require use of a physical training (PT) uniform during calisthenics.
Physical trauma Physical trauma refers to a physical injury. In medicine, however, the words trauma patient usually refer to someone who has suffered serious and life-threatening physical injury potentially resulting in secondary complications such as shock, respiratory failure and death.
Physical universe In religion and esotericism, the term "physical universe" or "material universe" is used to distinguish the physical matter of the universe from a proposed spiritual or supernatural essence.
Physical-to-Virtual Also known as "P2V" Physical-to-Virtual describes the process of decoupling and migrating a physical server's OS, applications, and data from a physical server to a virtual machine guest hosted on a virtualization platform.
Physician assistant In the United States, Physician Assistants (PAs) are non-physician clinicians licensed to practice medicine with a physician's supervision. This supervision, in most cases, need not be direct or on site and many PAs practice in remote or underserved areas in satellite clinics.
Physician Assistant and Nurse Practitioner Badge The Physician Assistant and Nurse Practitioner Badge is a military badge of the United States Coast Guard that is authorized for wear by commissioned officers of the US Coast Guard and US Public Health Service serving with the US Coast who serve as medical officers. The decoration is similar to the Air Force Medical Corps Pin.
Physician-patient privilege In the laws of many common law jurisdictions, the concept of legal privilege, or the rule that certain conversations are so private and confidential that they cannot be used as evidence in court, extends to communication between a patient and physician. Although the rule is sometimes thought to apply only to situations such as admissions made to a psychiatrist during treatment, this is only one case.
Physicians for Global Survival Physicians for Global Survival (PGS) is the Canadian chapter of International Physicians for the Prevention of Nuclear War (IPPNW). It is a physician peace activist group that has existed since the early 1980s.
Physicians for Human Rights Physicians for Human Rights (PHR) is an organization that promotes health by protecting human rights. It is an organization that believes that human rights are essential preconditions for the health and well-being of all people.
Physicians For Life Physicians For Life is an IRS nonprofit organization dealing with the issues of abortion, euthanasia, stem cell research, cloning, sexual education and various other life issues. Physicans For Life was founded in 1986, and has produced a series of pro-life brochures, booklets, and digests which are distributed throughout the USA, and internationally.
Physicians' Desk Reference The Physicians' Desk Reference (PDR) is a commercially published compilation of manufacturers' prescribing information (package insert) on prescription drugs, updated annually. While designed to provide physicians with the full legally mandated information relevant to writing prescriptions (just as its name suggests), it is widely available in libraries and bookstores, widely used by other medical specialists, and in significant part valuable to consumers.
Physicist A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena spanning all length scales: from the sub-atomic particles from which all ordinary matter is made (particle physics) to the behavior of the material Universe as a whole (cosmology).
Physics Physics (from the Greek, (phúsis), "nature" and (phusiké), "knowledge of nature") is the science concerned with the discovery and understanding of the fundamental laws which govern matter, energy, space, and time. Physics deals with the elementary constituents of the universe and their interactions, as well as the analysis of systems best understood in terms of these fundamental principles.
Physics (Aristotle) Physics (or "Physica", or "Physicae Auscultationes" meaning "lessons") is a key text in the philosophy of Aristotle. It inaugurates in the current Andronichean order, the long series of Aristotle's physical, cosmological and biological works, and is preliminary to them.
Physics (band) Physics was an instrumental band from San Diego, California, USA that had featured a rotating cast of musicians, but was mainly composed of Jeff Coad on synths, Rob Crow on guitars, Jason Soares on guitars, brothers Will Goff and John Goff on guitars/synths, and Cameron Jones on drums. Formed in late 1993, Physics was heavily influenced by Krautrock, minimalism, and electronic music, though were often lumped into the math rock genre.
Physics and Star Trek The science-fiction media franchise Star Trek has borrowed freely (but very loosely) from the scientific world to provide storylines. Episodes are replete with references to tachyon beams, baryon sweeps, quantum fluctuations and event horizons.
Physics card A physics card is an expansion card for computers, similar to a graphics card but which is used to process physics interactions as opposed to graphics. By taking over the processing of these effects, the CPU can use more of its power for other tasks.
Physics education Physics education refers both to the methods currently used to teach physics and to an area of pedagogical research that seeks to improve those methods. Historically, physics has been taught at the high school and college level primarily by the lecture method together with laboratory exercises aimed at verifying concepts taught in the lectures.
Physics engine A physics engine is a computer program that simulates Newtonian physics models, using variables such as mass, velocity, friction and wind resistance. It can simulate and predict effects under different conditions that would approximate what happens in real life or in a fantasy world.
Physics Essays Physics Essays is a quarterly journal founded and edited by Emilio Panarella, a fusion researcher and Chief Technology Officer of ALFT (formerly Advanced Laser and Fusion Technology). It was founded in 1988 and is subtitled "An International Journal Dedicated To Fundamental Questions In Physics".
Physics First Physics First is an educational program that teaches a basic physics course in the ninth grade (usually 15-year-olds), rather than the biology course which is more standard in public schools. It began as an organized movement among educators around 1990, and has been slowly catching on throughout the United States.
Physics of computation The study of the physics of computation relates to understanding the fundamental physical limits of computers. This field has led to the investigation of how thermodynamics limits information processing, the understanding of chaos and dynamical systems, and a rapidly growing effort to invent new quantum computers.
Physics of firearms From the viewpoint of physics (dynamics, to be exact), a firearm, as for most weapons, is a system for delivering maximum destructive energy to the target with minimum delivery of energy on the shooter. The force and momentum delivered to the target however cannot be any more than that (due to recoil) on the shooter.
Physics olympiad Physics olympiad is a competition in physics, usually among high school students, where the participants solve problems and/or perform and analyze experiments. In many countries, physics olympiads are held annually on a national level, forming a team of students representing the country in the International Physics Olympiad.
Physics processing unit A physics processing unit (PPU) is a dedicated microprocessor designed to handle the calculations of physics, especially in video games. Examples of calculations involving a PPU might include rigid body dynamics, soft body dynamics, collision detection, fluid dynamics, hair and clothing simulation, finite element analysis, and fracturing of objects.
Physics Today Physics Today magazine, created in 1948, is the membership journal of The American Institute of Physics. It is provided to 130,000 members of twelve physics societies, most importantly including the American Physical Society.
Physics World Physics World is the membership magazine of the Institute of Physics, one of the largest physical societies in the world. It is an international monthly magazine covering all areas of physics, both pure and applied, and is essential reading for physicists in research, industry and education worldwide.
Physics/wip <BR>This article is currently undergoing a full review, editor's contributions are welcomed to the process - please be careful with your edits, making sure they reflect a consensus that has been reached by the review process<BR>
PhysicsWeb PhysicsWeb is a web site providing various up-to-date information relating to the study and application of physics. The most significant content of the site is news, employment, and upcoming-events-related information.
Physicx Physicx (Real name: Kim Hyo-Gun, Hangul: 김효근, born on 23 August 1984 in South Korea) is a male South Korean B-boy, commonly known as breakdancer. Currently he is a member of a Korean B-boy crew named Rivers and a project team named Project Soul.
Physikalisch-Technische Bundesanstalt The Physikalisch-Technische Bundesanstalt (PTB) is based in Braunschweig and Berlin. It is the national institute for natural and engineering sciences and the highest technical authority for metrology and physical safety engineering in Germany.
Physiocrats The physiocrats were a group of economists who believed that the wealth of nations was derived solely from agriculture. Their theories originated in France and were most popular during the second half of the 18th century.
Physiognomy Physiognomy (Gk. physis, nature and gnomon, judge, interpreter) is a theory and a folk science based upon the idea that the study and judgement of a person's outer appearance, primarily the face, may give insights into their character or personality.
Physiographic regions of Peru When the Spanish arrived, they divided Peru (because of political reasons) in three main regions: the Coastal region, that is bounded by the Pacific Ocean; the Highlands, that is located on the Andean Heights, and the Jungle, that is located on the Amazonian Jungle. But Javier Pulgar Vidal, a geographer who studied the biogeographic reality of the Peruvian territory for a long time, proposed the creation of eight Natural Regions.
Physiologia Plantarum Physiologia Plantarum Is a pay to publish "scientific journal". For publishing, researchers must pay up to $65 a page and up to $2500 for web-publishing, in addition to paying for a subscription membership.
Physiological age The definition of physiological age can be thought as a person's age as estimated by his or her body's health and probable life expectancy. Physiological age is opposite of to chronological age which is your actual age.
Physiological interaction Physiological interaction goes beyond the physical interfaces that a computer has, which would include the input and output devices. Physiological interfaces actually secure and use real body characteristics, including breathing, talking, and height and weight.
Physiological plant disorders Physiological plant disorders are caused by non-pathological disorders such as poor light, weather damage, water-logging or a lack of nutrients, and affect the functioning of the plant system. Physiological disorder are distinguished from plant diseases caused by pathogens, such as a virus or fungus.
Physiological psychology Physiological psychology is a subdivision of biological psychology that studies the neural mechanisms of behavior through direct manipulation of the brains of nonhuman animal subjects in controlled experiments.Pinel, J.
Physiologically-based pharmacokinetic modelling Physiologically-based pharmacokinetic modeling (PBPK) is a mathematical modelling technique for prediction of the absoption, distibution, metabolization and excretion (AMDE) of a compound in humans and other species used in pharmaceutical research.
Physisorption PhysisorptionIUPAC Gold Book definition of physical adsorption or physical adsorption is a type of adsorption in which the adsorbate adheres to the surface only through Van der Waals force (weak intermolecular) interactions, the same that are responsible for the imperfection of real gases and the condensation of vapors. It is characterised by:IUPAC on properties of physisorption
Physitheism Physitheism is the attribution of a physical form and attributes to deities, a practice associated with the ancient Greeks and to a lesser extent the Romans. In modern Jewish and Christian theology the Abrahamic God is held to be a transcendent spirit with no body parts.
Physual The word physual is an amalgam that combines the three words physical, virtual and visual. Physual is the basis for the framework Physual Designing, a theoretical framework for engineering collaboration in geographically dispersed teams.
Phytanic acid Phytanic acid (or 3,7,11,15-tetramethyl hexadecanoic acid) is present in human diet or in animal tissues where it may be derived from chlorophyll in plant extracts. Phytanic acid derives from the corresponding alcohol, phytol, and is oxidized into pristanic acid.
Phytelephas Phytelephas (Ivory Palm) is a genus of five species of palms, native to tropical South America. The genus name means 'plant elephant', which refers to the very hard, white seed endospem, which resembles (and can be used as a substitute for) elephant ivory.
Phytelephas aequatorialis The palm tree Phytelephas aequatorialis, which bears the common names tagua palm and ivory-nut palm, is a main source of vegetable ivory, or tagua, a botanical alternative to ivory. This palm is found in the tropical rainforests of South America, especially in Ecuador.
Phytic acid Phytic acid (known as inositol hexaphosphate (IP6), or phytate when its salt form) is the principal storage form of phosphorus in many plant tissues, especially bran and seeds. Phosphorus in this form is generally not bioavailable to non-ruminant animals because they lack the digestive enzyme, phytase, required to separate phosphorus from the phytate molecule.
Phytoalexin Phytoalexins are antibiotics produced by plants that are under attack. Phytoalexins tend to fall into several classes including terpenoids, glycosteroids and alkaloids; however, researchers often find it convenient to extend the definition to include all phytochemicals that are part of the plant's defensive arsenal.
Phytogenics Phytogenics are a group of Natural Growth Promoters (NGPs) or Non-antibiotic Growth Promoters, derived from herbs, spices or other plants. They are commonly regarded as favorable alternatives to Antibiotic Growth Promoters (AGPs) in livestock production.
Phytogeography Phytogeography is the branch of biogeography that is concerned with the geographic distribution of plant species, or more generally, plants. Phytogeography is concerned with all aspects of plant distribution, from the controls on the distribution of individual species ranges to the factors that govern the composition of entire communities and floras.
Phytophthora Phytophthora (from Greek phytón, “plant” and phthorá, “destruction, destruction”; “the plant-destroyer”) is a genus of plant-damaging Protisten of the Oomycetes (water moulds). Heinrich Anton de Bary described it for the first time in 1875.
Phytoplasma Phytoplasma, formerly known as 'Mycoplasma-like organisms' or MLOs, are specialised wall-less bacteria that are obligate parasites of plant phloem tissue, and some insects. They can't be cultured in vitro in cell-free media.
Phytoremediation, Hyperaccumulators This table was originally provided by Stevie Famulari for her students at the University of New Mexico Landscape Architecture Department, for a phytoremediation project regarding the drainage canyon of the Manhattan Project at Los Alamos, New Mexico. It has now grown into three sections.
Phytosaur Phytosaurs - family Phytosauridae or Parasuchidae - were a group of large (2 to 12 meters long - average size 3 to 4 meters) semi-aquatic predatory archosaurs that flourished during the Late Triassic period. These long snouted and heavily armoured archosaurs bore a remarkable resemblance to modern crocodiles in size, appearance, and (clearly) lifestyle, an example of convergence or parallel evolution.
Phytosociology Phytosociology is the study of the characteristics, classification, relationships, and distribution of plant communities. A phytosociological system is a system for classifying these communities. It is often suggested that it is not a Science in its formal sense.
Phytosterol Phytosterols (also called plant sterols) are a group of steroid alcohol, phytochemicals naturally occurring in plants. They are white powders with mild, characteristic odor, insoluble in water and soluble in alcohols.
Phytotelma A phytotelma is a terminus for small and discrete water bodies held by plants. The water accumulated on these plants may serve as substratum for associated fauna, sometimes the fauna associated with phytotelmata is unique.
Phytotreatment Phytotreatment is an environmental term referring to the cultivation of specialized plants that absorb specific contaminants from the soil through their roots or foliage. This reduces the concentration of contaminants in the soil, but incorporates them into biomasses that may be released back into the environment when the plant dies or is harvested.
PH pH is a measure of the acidity and the base of a solution in terms of activity of hydrogen (H+). For dilute solutions, however, it is convenient to substitute the activity of the hydrogen ions with the molarity (mol/L) of the hydrogen ions (however, this is not necessarily accurate at higher concentrations http://www.
PH helmet The P helmet, PH helmet and PHG helmet were early types of gas mask issued by the British Army in the First World War, to protect troops against chlorine, phosgene and tear gases. Rather than having a separate filter for removing the toxic chemicals, they consisted of a gas-permeable hood worn over the head which was treated with chemicals.
PH indicator A pH indicator is a halochromic chemical compound that is added in small amounts to a solution so that the pH (acidity or alkalinity) of the solution can be determined easily. Hence a pH indicator is a chemical detector for hydronium ions (H3O+) (or Hydrogen ions (H+) in the Arrhenius model).
PH meter A pH meter is an electronic instrument used to measure the pH (acidity or basicity) of a liquid (though special probes are sometimes used to measure the pH of semi-solid substances, such as cheese). A typical pH meter consists of a special measuring probe (a glass electrode) connected to an electronic meter that measures and displays the pH reading.
PH-32 PH-32 is a former Nike Missile launch site in Marlton, New Jersey. Opened in 1955, the site was apart of a ring of 12 Nike sites intended to protect the population and military installations of the Philadelphia area during the Cold War, specifically from attack by Soviet bomber aircraft.
PH-DVD PH-DVD supposedly is an optical storage format which aims to surpass Blu-ray and HD DVD in storage capacity, where "PH" stands for Polar High-definition. It was publicly announced on March 30, 2006, by a company called Polarizonics Corp.
PH10 pH10 is an electronic recording artist and performance group currently out of Denver, Colorado, USA. The group was formed by Recone Helmut and Clark ov Saturn, former members of LD-50, an industrial rock quartet from Denver in the late 1990's.
PHaSR PHaSR , acronym for Personnel Halting and Stimulation Response, developed by ScorpWorks, is a hand-held single-operator non-lethal deterrent weapon. PHaSR was eveloped by the Air Force laboratory's Directed Energy Directorate.
PHAMALy The Physically Handicapped Actors & Musical Artists League, or PHAMALy, is a theater group and touring company formed in 1989 when a group of former students of the Boettcher School in Denver, Colorado, frustrated with the lack of theatrical opportunities for people with disabilities, decided to act. PHAMALy performs at the Denver Center for the Performing Arts and the Aurora Fox Theatre.
PHAROS PHAROS IPA: ['feÉ™.rĘŚs] (Platform for Search of Audiovisual Resources Across Online Spaces) is the name given to a planned (and currently being developed) European Internet multimedia search engine led by norwegian Fast Search & Transfer.
PHENIX PHENIX (Pioneering High Energy Nuclear Interactions eXperiment) is one of the four experiments at the Relativistic Heavy Ion Collider located at the Brookhaven National Laboratory. Its primary research goals are the discovery and the examination of the quark gluon plasma, a state of matter where the strong interaction is dominant and the quarks and gluons are not bound in hadrons, and the analysis of the spin structure of the proton.
PHI-base The Pathogen - Host Interaction database (PHI-base) contains expertly curated molecular and biological information on genes proven to affect the outcome of pathogen-host interactions. The database was created and is maintained by researchers at Rothamsted Experimental Station.
PHIGS PHIGS (Programmer's Hierarchical Interactive Graphics System) is an API standard for rendering 3D computer graphics, at one time considered to be the 3D graphics standard for the 1990s. Instead a combination of features and power led to the rise of OpenGL, which remains the de facto 3D standard to this day.
PHILM 1 pHILM #1 was a 10" vinyl single by Coil under the alias ELpH on the newly formed Eskaton label under catalogue number Eskaton 003. This single featured a version of "pHILM #1" with vocals, unlike the Born Again Pagans version.
PHP PHP (PHP: Hypertext Preprocessor) is a reflective programming language originally designed for producing dynamic Web pages. PHP is used mainly in server-side application software, but can be used from a command line interface or in standalone graphical applications.
PHP accelerator PHP accelerator is the common name given to an extension designed to boost the performance of software applications written using the PHP programming language. Most work by caching the compiled bytecode form of PHP scripts to avoid the overhead on every page request of parsing and compiling source code that may never even get executed.
PHP-Fusion PHP-Fusion is a light-weight open-source content management system (CMS) written and developed by Nick Jones in PHP. It uses a MySQL database to store a web site's content and comes with a simple but comprehensive administration system.
PHP-GTK PHP-GTK is an extension for the PHP programming language that implements language bindings for GTK+. It provides an object-oriented interface to GTK+ classes and functions and greatly simplifies writing client-side cross-platform GUI applications.
PHP/Java Bridge PHP/Java Bridge is a XML-based network protocol, which can be used to connect the native script engine PHP with a Java or ECMA 335 virtual machine. The PHP/Java Bridge allows developers to access Java classes from within PHP scripts.
PHPEdit PHPEdit is a commercial IDE developed by WaterProof SARL. It is written in Delphi and runs on the Microsoft Windows operating system, and is designed mainly for the PHP language, but supports many other languages such as CSS, HTML, Javascript, Ini, PHPEditScript, PHP, PlainText, SQL, XML, and XSLT.
PHROOT PHROOT stands for PHP Rapid Object Oriented Technology (and is a framework] that is generally modeled for object oriented [[PHP after the server <-> client abstraction taken from the basic specifications and interfaces of the Java programming language.
PHUHS Palm Harbor University High School, also known as "PHUHS", is a nationally-performing public high school for grades 9-12 located in Palm Harbor, Florida. The school's nickname is the "Hurricanes" and the school's colors are navy and maroon.
PHW Business School PHW Business School is a Swiss higher education institution. It is part of the federally accredited Kalaidos University of Applied Sciences, one of eight such universities accredited by the Swiss Federal Council.
Pi The mathematical constant π is an irrational real number, approximately equal to 3.14159, which is the ratio of a circle's circumference to its diameter in Euclidean geometry, and has many uses in mathematics, physics, and engineering.
Pi bond In chemistry, pi bonds (Ď€ bonds) are covalent chemical bonds where two lobes of one involved electron orbital overlap two lobes of the other involved electron orbital. Only one of the orbital's nodal planes passes through both of the involved nuclei.
Pi Beta Alpha Pi Beta Alpha is a fictitious sorority in the Sweet Valley High book series. The sorority is the most popular on the SVH campus, and because of the haughtiness of some of it's members, also called the snobbiest.

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