Encyclopedia

Nuclear energy policy Nuclear energy policy is national and international policy concerning some or all aspects of nuclear energy, such as mining for nuclear fuel, generating electricity by nuclear power, enriching and storing spent nuclear fuel and nuclear fuel reprocessing.
Nuclear energy policy/workspace Nuclear energy policy is national and international policy concerning some or all aspects of nuclear energy, such as mining for nuclear fuel, generating electricity by nuclear power, enriching and storing spent nuclear fuel and nuclear fuel reprocessing.
Nuclear engineering Nuclear engineering is the practical application of the atomic nucleus gleaned from principles of nuclear physics and the interaction and maintenance of nuclear fission systems and components, specifically, nuclear reactors, nuclear power plants and/or nuclear weapons. The field can also include the study of nuclear fusion, medical applications of radiation, nuclear safety, heat transport, nuclear fuels technology, nuclear proliferation, and the effect of radioactive waste or radioactivity in the environment.
Nuclear envelope The nuclear envelope (also known as the perinuclear envelope, nuclear membrane, nucleolemma or karyotheca) is the double membrane of the nucleus that encloses genetic material in eukaryotic cells. It separates the contents of the nucleus (DNA in particular) from the cytosol.
Nuclear espionage Nuclear espionage is the purposeful giving of state secrets regarding nuclear weapons to other states without authorization (espionage). During the history of nuclear weapons there have been many cases of known nuclear espionage, and also many cases of suspected or alleged espionage.
Nuclear explosive A nuclear explosive is an explosive device that derives its energy from nuclear reactions. Almost all nuclear explosive devices that have been designed and produced, and the two that have actually been used, are nuclear weapons intended for warfare; see that article for more detail.
Nuclear export signal A nuclear export signal (NES) is a short amino acid sequence in a protein that targets it for export from the cell nucleus to the cytoplasm through the nuclear pore complex. It has the opposite effect of a nuclear localization signal, which targets a protein located in the cytoplasm for import to the nucleus.
Nuclear Emergency Support Team The Nuclear Emergency Support Team (NEST) (formerly known as the Nuclear Emergency Search Team) is a team of scientists, technicians, and engineers operating under the United States Department of Energy's National Nuclear Security Administration (NNSA). Their task is to be "prepared to respond immediately to any type of radiological accident or incident anywhere in the world".
Nuclear Energy Agency The Nuclear Energy Agency is an intergovernmental multinational agency that is organized under the Organisation for Economic Co-operation and Development. Originally formed on 1 February 1958 with the name European Nuclear Energy Agency (ENEA) (the United States participated as an Associate Member), the name was changed in 1972 to its current name after Japan became a member.
Nuclear Energy Board The Nuclear Energy BoardThe Nuclear Energy Board was officially titled as "An Bord Fuinnimh Núicléigh", this been from the Irish language, however invariably the English language title—though unofficial—was used in practice. (NEB) was established in Ireland on November 30, 1973 by the Nuclear Energy (An Bord Fuinnimh Núicléigh) Act, 1971.
Nuclear Energy Institute According to its website, the Nuclear Energy Institute (NEI) is "the policy organization of the nuclear energy and technologies industry and participates in both the national and global policy-making process. NEI's objective is to ensure the formation of policies that promote the beneficial uses of nuclear energies and technologies in the United States and around the world.
Nuclear fallout Fallout is the residual radiation hazard from a nuclear explosion, so named because it "falls out" of the atmosphere into which it is spread during the explosion. It commonly refers to the radioactive dust created when a nuclear weapon explodes.
Nuclear family The term nuclear family was developed in the western world to distinguish the family group consisting of parents (usually a father and mother) and their children, from what is known as an extended family. According to Merriam-Webster the term dates back to 1947 and is therefore relatively new, although nuclear family structures themselves are not.
Nuclear flask A Nuclear Flask is a railway wagon which is used to transport waste nuclear materials between many power stations in the UK. A nuclear flask consists of 4 layers - a container flask, a 5" thick flask protector, a 12" thick flask and a 2" thick layer of steel panels.
Nuclear freeze The nuclear freeze was a proposed agreement between the world's nuclear powers, primarily the United States and the then-Soviet Union, to freeze all production of new nuclear arms and to leave levels of nuclear armament where they currently were. However, the difference in the systems between the two nations meant that while the proposal was widely publicized and debated in the United States, there is little evidence that this occurred within the Soviet Union.
Nuclear fuel Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. By far the most common type of nuclear fuel is heavy fissile elements that can be made to undergo nuclear fission chain reactions in a nuclear fission reactor; nuclear fuel can refer to the material or to physical objects (for example fuel bundles composed of fuel rods) composed of the fuel material, perhaps mixed with structural, neutron moderating, or neutron reflecting materials.
Nuclear fuel and reactor accidents This page is devoted to a discussion of how uranium dioxide nuclear fuel behaves during both normal nuclear reactor operation and under reactor accident conditions such as overheating. Work in this area is often very expensive to conduct, and so has often been performed on a collaborative basis between groups of countries, usually under the aegis of the CSNI.
Nuclear fuel bank A nuclear fuel bank is a proposed approach to provide countries access to enriched nuclear fuel, without the need for them to have access to enrichment technology. The basic concept is that countries, who have enrichment technology, would donate an amount of enriched fuel to a "bank".
Nuclear fuel cycle The nuclear fuel cycle, also called nuclear fuel chain, is the progression of nuclear fuel through a series of differing stages. It consists of steps in the front end, which are the preparation of the fuel, steps in the service period in which the fuel is used during reactor operation, and steps in the back end, which are necessary to safely manage, contain, and either reprocess or dispose of spent nuclear fuel.
Nuclear fusion In physics and nuclear chemistry, nuclear fusion is the process by which multiple nuclei join together to form a heavier nucleus. It is accompanied by the release or absorption of energy depending on the masses of the nuclei involved.
Nuclear Football The "Nuclear Football," otherwise known as the President's Emergency Satchel, and sometimes also referred to as The Button is a specially-outfitted, black-colored briefcase used by the President of the United States to authorize the use of nuclear weapons. Adopted to permit the President to make a nuclear attack order while away from fixed command centers, such as the White House Situation Room, it functions as a mobile node in the strategic defense system of the United States.
Nuclear Free World Policy The Nuclear Free World Policy is a commitment by the governments of Brazil, Egypt, Ireland, Mexico, New Zealand, Slovenia, South Africa, and Sweden to shape foreign policy around the goal of "the elimination of nuclear weapons and assurance that they will never be produced again." Of particular concern to the signatories are the states who have refused to sign the Nuclear Non-Proliferation Treaty.
Nuclear Fuel Cycle Information System The International Nuclear Fuel Cycle Information System (NFCIS) is a database maintained by the International Atomic Energy Agency (IAEA) to store trustable information on nuclear fuel cycle facilities around the world. The NFCIS contains information submitted by IAEA member countries as well as public information.
Nuclear gene Nuclear gene is a gene located in the cell nucleus of an eukaryote. The term is used to distinguish nuclear genes from the genes in the mitochondrion, or in case of plants, also the chloroplast, which host their own genetic system and can produce proteins from scratch.
Nuclear halo In nuclear physics, an atomic nucleus is said to be a halo if its radius is appreciably larger than that predicted by the liquid drop model, wherein the nucleus is assumed to be a sphere of constant density. For a nucleus of mass number A, the radius r is(approximately):
Nuclear isomer A nuclear isomer is a metastable state of an atomic nucleus caused by the excitation of one or more of its protons or neutrons or both. A nuclear isomer occupies a higher energy state than the corresponding non-excited nucleus, called the ground state.
Nuclear lamina The nuclear lamina is a dense, ~ 30 to 100 nanometers thick, fibrillar network composed of intermediate filaments made of lamin that lines the inner surface of the nuclear envelope. At the onset of mitosis, a certain cyclin-dependent kinase complex (Cdk1 and cyclin B in mammals) phosphorylates the lamins, causing them to undergo a conformational change that triggers the disassembly of the nuclear envelope.
Nuclear localization signal A nuclear localizing sequence (NLS) is an amino acid sequence which acts like a 'tag' on the exposed surface of a protein. This sequence is used to confine the protein to the cell nucleus through the Nuclear Pore Complex and to direct a newly synthesized protein into the nucleus via its recognition by cytosolic nuclear transport receptors.
Nuclear Liabilities Fund The Nuclear Liabilities Fund was created by the British Government in November 2004 to assume the long-term financial liabilities from spent nuclear fuels. The Fund is a mixture of state-funding (estimated between ÂŁ175m and ÂŁ200m) and private contributions (British Energy is required under its restructuring to provide 65 per cent of its profits to the fund).
Nuclear magnetic moment The nuclear magnetic moment is the magnetic moment of an atomic nucleus and arises from the spin of the protons and neutrons. It is mainly a magnetic dipole moment; the quadrupole moment does cause some small shifts in the hyperfine structure as well.
Nuclear material Nuclear material consists of materials used in nuclear systems, such as nuclear reactors and nuclear weapons. Most commonly this refers to special nuclear material (SNM) as defined in the United States Atomic Energy Act.
Nuclear matrix In biology, the nuclear matrix is the network of fibres found throughout the inside of a cell nucleus and is analagous to the cell cytoskeleton. The exact function of this matrix is still disputed, and it's very existence has recently been called into question.
Nuclear medicine Nuclear medicine is a branch of medicine and medical imaging that uses the nuclear properties of matter in diagnosis and therapy. Many procedures in nuclear medicine use radionuclides, or pharmaceuticals that have been labeled with radionuclides (radiopharmaceuticals).
Nuclear meltdown A nuclear meltdown occurs when the core of a nuclear reactor ceases to be properly controlled and cooled due to failure of control or safety systems, and fuel assemblies (containing the uranium or plutonium reactor fuel and highly radioactive fission products) inside the reactor begin to overheat and melt. A meltdown is considered a serious nuclear accident because of the possibility that a nuclear meltdown will defeat the reactor containment and potentially release highly radioactive fission products to the environment.
Nuclear navy Nuclear navy, or nuclear powered navy consists of ships powered by relatively small onboard nuclear reactors known as naval reactors. The concept was revolutionary for naval warfare when first proposed, as it meant that these vessels did not need to stop for fuel like their conventional counterparts, being limited only by crew endurance and supplies.
Nuclear Non-Proliferation Treaty . The previous United Kingdom Secretary of State for Defence, Geoff Hoon, has also explicitly invoked the possibility of the use of the country's nuclear weapons in response to a non-conventional attack by "rogue states"UK 'prepared to use nuclear weapons' BBC article dated 20 March, 2002.
Nuclear operator In mathematics, a nuclear operator is roughly a compact operator for which a trace may be defined, such that the trace is finite and independent of the choice of basis (at least on well behaved spaces; there are some spaces on which nuclear operators do not have a trace).
Nuclear option The Nuclear Option, also called the Constitutional Option, is a parliamentary ruling by the presiding officer of the United States Senate to end debate and hold an immediate vote on a matter under consideration. This procedure is not provided for in the formal rules of Senate, but has been used on various occasions for the purpose of frustrating a filibuster or other dilatory tactic.
Nuclear Overhauser effect In chemistry, the transfer of spin polarization from one spin population to another is generally called Overhauser Effect, after American physicist Albert Overhauser who hypothesized it in the early 1950s. The phenomenon was demonstrated by C.
Nuclear pharmacy Nuclear Pharmacy involves the preparation of radioactive materials that will be used to diagnose and treat specific diseases. It was the first pharmacy specialty established in 1978 by the Board of Pharmaceutical Specialties.
Nuclear photonic rocket In a nuclear photonic rocket, a nuclear reactor would generate such high temperatures that the blackbody radiation from the reactor would provide significant thrust. Think of a nuclear lightbulb, with a reflector: the advantage is that no material exhaust is required.
Nuclear physics Nuclear physics is the branch of physics concerned with the nucleus of the atom. It has three main aspects: probing the fundamental particles (protons and neutrons) and their interactions, classifying and interpreting the properties of nuclei, and providing technological advances.
Nuclear poison A nuclear poison, also called a neutron poison is a substance with a large neutron absorption cross-section in applications, such as nuclear reactors, when absorbing neutrons is an undesirable effect. However neutron-absorbing materials also called poisons, are intentionally inserted into some types of reactors in order to lower the high reactivity of their initial fresh fuel load.
Nuclear pore Nuclear pores are large protein complexes that cross the nuclear envelope, which is the double membrane surrounding the eukaryotic cell nucleus. There are about on average 2000 nuclear pore complexes in the nuclear envelope of a vertebrate cell, but it varies depending on the number of transcriptions of the cell.
Nuclear power Nuclear power is the controlled use of nuclear reactions to release energy for work including propulsion, heat, and the generation of electricity. Human use of nuclear power to do significant useful work is currently limited to nuclear fission and radioactive decay.
Nuclear power controversy After a period of decline following the 1979 Three Mile Island accident and the 1986 incident at Chernobyl, there is a recently renewed interest in nuclear energy because it could partially address both dwindling oil reserves and global warming with far fewer emissions of greenhouse gases than fossil fuel.
Nuclear power in Canada Despite its small population Canada has an active and independent nuclear power and research sector. A leading exporter of uranium, Canada also exports nuclear technology within the terms of the Nuclear Non-proliferation Treaty, which it is a signatory to.
Nuclear power in France In France, as of 2002, EDF - the country's main electricity generation and distribution company - produces about 78% of its electricity with 58 nuclear power plants (making it the leading world country in its usage of nuclear power).
Nuclear power in Germany Nuclear power in Germany has been high on the political agenda in recent decades, with continuing debates about whether of not the technology should be phased out. The topic received renewed attention at the start of 2007 due to the political impact of the Russia-Belarus energy dispute.
Nuclear powered icebreaker A nuclear powered icebreaker is a purpose-built ship for use in waters continuously covered with ice. Icebreakers are ships capable of cruising on ice-covered water by breaking through the ice with their strong, heavy, steel bows.
Nuclear program of Indonesia The nuclear program of Indonesia includes plans to build nuclear reactors in the country to produce nuclear power for peaceful purposes. The national legislative organ for nuclear energy, Badan Pengawas Tenaga Nuklir (BAPETEN), was founded in 1998.
Nuclear proliferation Nuclear proliferation is the spread of nuclear weapons production technology and knowledge to nations that do not already have such capabilities. It has been opposed by many nations with and without nuclear weapons, who fear that more countries with nuclear weapons may increase the possibility of nuclear warfare, de-stabilize international or regional relations, or infringe upon the national sovereignty of individual nation-states.
Nuclear propulsion Nuclear propulsion includes a wide variety of propulsion methods that use some form of nuclear reaction as their primary power source. Many military submarines and a growing figure - with crude prices and emission in mind -
Nuclear pulse propulsion Nuclear pulse propulsion (or External Pulsed Plasma Propulsion, as it is termed in one recent NASA document) is a proposed method of spacecraft propulsion that uses nuclear explosions for thrust. It was first developed as Project Orion by DARPA, after a suggestion by Stanislaw Ulam in 1957.
Nuclear quadrupole resonance Nuclear quadrupole resonance or NQR is a technique related to nuclear magnetic resonance (NMR) which is used to detect atoms whose nuclei have a nuclear quadrupole moment, such as 14N, 35Cl and 63Cu. Since unlike NMR, NQR is done in an environment without a static (or DC) magnetic field, it is sometimes called "zero-field NMR".
Nuclear reactor A nuclear reactor is a device in which nuclear chain reactions are initiated, controlled, and sustained at a steady rate (as opposed to a nuclear bomb, in which the chain reaction occurs in a fraction of a second and is completely uncontrolled).
Nuclear reactor physics Most nuclear reactors use a chain reaction to induce a controlled rate of nuclear fission in fissile material, releasing both energy and free neutrons. A reactor consists of an assembly of nuclear fuel (a reactor core), usually surrounded by a neutron moderator such as water, graphite, or zirconium hydride, and fitted with mechanisms such as control rods that control the rate of the reaction.
Nuclear run-on A nuclear run-on assay is conducted to identify the genes that are being transcribed at a certain point in time. Cell nuclei are isolated rapidly, and incubated with labelled nucleotides and the results are hybridized to a slot blot, which is then exposed to film.
Nuclear Reactor Operator Badge The Nuclear Reactor Operator Badge is a decoration of the United States Army which was issued between the years of 1965 and 1990. In 1991, the decoration was declared obsolete by Army Regulation 672-5-1, however uniform regulations permit the continued wearing of the Nuclear Reactor Operator Badge before the decoration was discontinued.
Nuclear Regulatory Commission Nuclear Regulatory Commission (or NRC) is a United States government agency that was established by the Energy Reorganization Act in 1974, and was first opened January 19, 1975. The NRC took over the role of oversight of nuclear energy matters and nuclear safety from the AEC, or Atomic Energy Commission.
Nuclear Research and Consultancy Group Nuclear Research and Consultancy Group (NRG) is a Dutch institute that performs nuclear research for the government and private companies. It is the most important producer of radionuclides in Europe and maintains and operates the Petten nuclear reactor.
Nuclear salt-water rocket A nuclear salt-water rocket is a type of nuclear thermal rocket designed by Robert Zubrin that would be fueled by water bearing dissolved salts of plutonium or U235. These would be stored in tanks that would prevent a critical mass from forming by some combination of geometry or neutron absorption.
Nuclear sharing Nuclear sharing is a concept in NATO's policy of nuclear deterrence, which involves member countries without nuclear weapons of their own in the planning for the use of nuclear weapons by NATO, and in particular provides for the armed forces of these countries to be involved in delivering these weapons in the event of their use.
Nuclear space In mathematics, a nuclear space is a topological vector space with many of the good properties of finite dimensional vector spaces. The topology on them can be defined by a family of seminorms whose unit balls decrease rapidly in size.
Nuclear structure This page is an adapted translation of the corresponding fr:Structure nucléaire - As will be noted, there remain void paragraphs, as on the original. Competent Wikipedians are welcome to enrich it, and their contributions will be translated back to fr:
Nuclear summer A Nuclear summer is a hypothetical scenario resulting from nuclear warfare that would follow a nuclear winter. In this scenario, the amount of water in the stratosphere would increase, causing greenhouse warming of the surface.
Nuclear Safety and Control Act The Nuclear Safety and Control Act (NSCA) of Canada replaced the Atomic Energy Control Act of 1946 with new, more effective and explicit legislation to regulate the activities of the Canadian nuclear industry. The NSCA also provided for the establishment of the Canadian Nuclear Safety Commission (CNSC), which replaced the Atomic Energy Control Board (AECB).
Nuclear Spectroscopic Telescope Array The Nuclear Spectroscopic Telescope Array, or NuSTAR, was intended to be a space-based X-ray telescope such as Chandra X-ray Observatory and XMM-Newton. The program was cancelled in February 2006 as NASA presented its 2007 budget.
Nuclear Suppliers Group The Nuclear Suppliers Group (NSG) is a multinational body concerned with reducing nuclear proliferation by controlling the export and re-transfer of materials that may be applicable to nuclear weapon development and by improving safeguards and protection on existing materials.
Nuclear thermal rocket In a nuclear thermal rocket a working fluid, usually hydrogen, is heated in a high temperature nuclear reactor, and then expands through a rocket nozzle to create thrust. The nuclear reactor's energy replaces the chemical energy of the reactive chemicals in a traditional rocket engine.
Nuclear transport The entry and exit of large molecules from the cell nucleus is tightly controlled by the nuclear pore complexes (NPCs). Although small molecules can enter the nucleus without regulation, macromolecules such as RNA and proteins require association with karyopherins called importins to enter the nucleus and exportins to exit.
Nuclear triad In nuclear strategy, the nuclear triad refers to the three tiers of a country's nuclear arsenal, comprising strategic bombers, intercontinental ballistic missiles (ICBMs), and ballistic missile submarines (SSBNs).
Nuclear utilization target selection Nuclear utilization target selection (NUTS) was a strategy developed during the Cold War as a means for one world nuclear power to achieve victory against another world nuclear power. To be victorious, the attacker had to destroy the target country's nuclear arsenal in a massive first strike.
Nuclear warfare Nuclear warfare, or atomic warfare, is a war in which nuclear weapons are used. In the history of nuclear weapons, they have only ever been used twice in a state of war (the atomic bombings of Hiroshima and Nagasaki), and only by one side in the confrontation, the United States of America.
Nuclear weapon A nuclear weapon is a weapon which derives its destructive force from nuclear reactions of fission or fusion. As a result, even a nuclear weapon with a small yield is significantly more powerful than the largest conventional explosives, and a single weapon is capable of destroying an entire city.
Nuclear weapon design Nuclear weapon designs are physical, chemical, and engineering arrangements which allow for the detonation of a nuclear weapon. They are often divided into two classes, based on the dominant source of the weapon's energy.
Nuclear weapon yield The explosive yield of a nuclear weapon is the amount of energy, called the yield, discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene (TNT), either in kilotons (thousands of tons of TNT) or megatons (millions of tons of TNT), but sometimes also in terajoules (1 kiloton of TNT = 4.184 TJ).
Nuclear weapons and the United Kingdom The United Kingdom was the third country to test an independently developed nuclear weapon in October 1952. It is one of the five "Nuclear Weapons States" (NWS) under the Nuclear Non-Proliferation Treaty, which the UK ratified in 1968.
Nuclear weapons and the United States The United States was the first country in the world to successfully develop nuclear weapons, and is the only country to have used them in war against another nation. During the Cold War it conducted over a thousand nuclear tests and developed many long-range weapon delivery systems.
Nuclear weapons in popular culture Since their dramatic public debut in August 1945, nuclear weapons have been a recurring motif in popular culture, to the extent that the decades of the Cold War are often referred to as the "atomic age."
Nuclear winter Nuclear winter is a hypothetical global climate condition that is predicted to be a possible outcome of a large-scale nuclear war. It is thought that severely cold weather can be caused by detonating large numbers of nuclear weapons, especially over flammable targets such as cities, where large amounts of smoke and soot would be injected into the Earth's stratosphere.
Nuclear Waste Management Organization (Canada) The Nuclear Waste Management Organization (NWMO) of Canada was established under the Nuclear Fuel Waste Act (NFWA) to investigate approaches for managing Canada’s used nuclear fuel. Used nuclear fuel is a by-product of the generation of electricity in a nuclear power plant.
Nuclear Waste News Nuclear Waste News is a biweekly newsletter covering the controversies surrounding the storage, treatment, transport, and disposal of radioactive waste. Features reporting on DOE and EPA regulation … news on the proposed Yucca Mountain repository, the Uniontown landfill, and other sites … the impact of homeland security on nuclear waste policy, storage, transport, and funding … legal developments … business reporting … development of GNEP technology … and more.
Nuclear Waste Policy Act The Nuclear Waste Policy Act is a United States federal law enacted in 1982. It established a national program for disposal of highly radioactive wastes, and resulted in the studying of Yucca Mountain as a possible site for long-term disposal of radioactive waste.
Nuclear-Free Future Award The Nuclear-Free Future Award is awarded to people committed against nuclear arms and energy. The award was donated after the World Uranium Hearing 1992 in Salzburg, Austria, and is awarded since 1998 in 3 categories: opposition, education and solution.
Nuclear-Weapon-Free Zone A Nuclear-Weapons-Free Zone, or NWFZ is defined by the United Nations] as an agreement, generally by internationally recognized treaty, to ban the use, development, or deployment of [[nuclear weapons in a given area. Additionally, this agreement has mechanisms of verification and control to enforce its obligations.
Nucleariid The nucleariids are a small group of amoebae with filose pseudopods, known mostly from soils and freshwater. They are distinguished from the similar vampyrellids mainly by having mitochondria with discoid cristae.
Nuclearism Nuclearism is the political philosophy or ideology that nuclear weapons are the best way of maintaining peace. An incisive exposition and cultural-environmental critique of this ideology is found in Piyush Mathur's article "Nuclearism: The Contours of a Political Ecology" published in the American journal Social Text (Spring 2001).
Nuclease A nuclease is an enzyme capable of cleaving the phosphodiester bonds between the nucleotide subunits of nucleic acids. Older papers may use terms such as "polynucleotidase" or "nucleodepolymerase"Avery, O.
Nuclease protection assay A nuclease protection assay is a laboratory test used in biochemistry and genetics to identify individual RNA molecules in a heterogeneous RNA sample extracted from cells. The technique can identify one or more RNA molecules of known sequence even at low total concentration.
Nuclei Armati Rivoluzionari The Nuclei Armati Rivoluzionari (NAR, Armed Revolutionary Nuclei) was an Italian neofascist terrorist organization active from 1977 to November 1981. It committed 33 murders in four years, and had projected to assassinate Francesco Cossiga, Gianfranco Fini and Adolfo Urso.
Nucleic acid A nucleic acid is a complex, high-molecular-weight biochemical macromolecule composed of nucleotide chains that convey genetic information. The most common nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Nucleic acid metabolism Nucleic acid metabolism is the process by which nucleotides are synthesized and degraded. Nucleic acid synthesis is an anabolic mechanism generally involving chemical reaction of phosphate, pentose sugar, and nitrogen base.
Nucleocapsid A Nucleocapsid is the genome (DNA or RNA) of a virus and the protein coat surrounding it (the capsid). There may be proteins complexed with the genome (nucleoproteins) that are also considered part of the nucleocapsid.
Nucleocosmogenesis Nucleocosmogenisis is a scientific term first coined and published by George Gamow, renown biophysicist, in the 1920s. According to his research, nucleocosmogenisis is the process by which all elements are created out of more fundamental components.
Nucleocosmochronology Nucleocosmochronology, also known as cosmochronology, is a relatively new technique used to determine timescales for astrophysical objects and events. This technique employs the abundances of radioactive nuclides in a way that is very similar to the use of C14 in dating archeological samples, save that the elements measured are typically uranium and thorium.
Nucleofuge A nucleofuge is a leaving group which retains the lone pair from its previous bond with another species. For example, in the SN2 mechanism a nucleophile attacks an organic compound containing the nucleofuge (the bromo group) which simultaneously breaks the bond with the nucleofuge.
Nucleoid In prokaryotes, the nucleoid (meaning nucleus-like and also known as the nuclear region, nuclear body or chromatin body) is an irregularly shaped region within the cell where the genetic material is localised. The nucleic acid is a circular, double-stranded piece of DNA and multiple copies may exist.
Nucleolus [of typical animal cell, showing subcellular components. Organelle]s: (1) nucleolus (2) [[cell nucleus|nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth ER (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles]]
Nucleomorph Nucleomorphs are small, reduced eukaryotic nuclei found in certain plastids. So far, only two groups of organisms are known to contain a nucleomorph: the cryptomonads of the supergroup Chromista and the chlorarachniophytes of the supergroup Rhizaria.

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