Outline of academic disciplines
An academic discipline or field of study is a branch of knowledge and researched as part of higher education. A scholar's discipline is defined by the university faculties and learned societies to which she or he belongs and the academic journals in which she or he publishes research. Disciplines vary between well-established ones that exist in all universities and have well-defined rosters of journals and conferences and nascent ones supported by only a few universities and publications. A discipline may have branches, these are called sub-disciplines. There is no consensus on how some academic disciplines should be classified, for example whether anthropology and linguistics are disciplines of the social sciences or of the humanities; the following outline is provided as topical guide to academic disciplines. Biblical studies Religious studies Biblical Hebrew, Biblical Greek, Aramaic Buddhist theology Christian theology Anglican theology Baptist theology Catholic theology Eastern Orthodox theology Protestant theology Hindu theology Jewish theology Muslim theology Biological anthropology Linguistic anthropology Cultural anthropology Social anthropology Archaeology Accounting Business management Finance Marketing Operations management Edaphology Environmental chemistry Environmental science Gemology Geochemistry Geodesy Physical geography Atmospheric science / Meteorology Biogeography / Phytogeography Climatology / Paleoclimatology / Palaeogeography Coastal geography / Oceanography Edaphology / Pedology or Soil science Geobiology Geology Geostatistics Glaciology Hydrology / Limnology / Hydrogeology Landscape ecology Quaternary science Geophysics Paleontology Paleobiology Paleoecology Astrobiology Astronomy Observational astronomy Gamma ray astronomy Infrared astronomy Microwave astronomy Optical astronomy Radio astronomy UV astronomy X-ray astronomy Astrophysics Gravitational astronomy Black holes Interstellar medium Numerical simulations Astrophysical plasma Galaxy formation and evolution High-energy astrophysics Hydrodynamics Magnetohydrodynamics Star formation Physical cosmology Stellar astrophysics Helioseismology Stellar evolution Stellar nucleosynthesis Planetary science Also a branch of electrical engineering Pure mathematics Applied mathematics Astrostatistics Biostatistics Academia Academic genealogy Curriculum Multidisciplinary approach Interdisciplinarity Transdisciplinarity Professions Classification of Instructional Programs Joint Academic Coding System List of fields of doctoral studies in the United States List of academic fields Abbott, Andrew.
Chaos of Disciplines. University of Chicago Press. ISBN 978-0-226-00101-2. Oleson, Alexandra; the Organization of knowledge in modern America, 1860-1920. ISBN 0-8018-2108-8. US Department of Education Institute of Education Sciences. Classification of Instructional Programs. National Center for Education Statistics. Classification of Instructional Programs: Developed by the U. S. Department of Education's National Center for Education Statistics to provide a taxonomic scheme that will support the accurate tracking and reporting of fields of study and program completions activity. Complete JACS from Higher Education Statistics Agency in the United Kingdom Australian and New Zealand Standard Research Classification Chapter 3 and Appendix 1: Fields of research classification. Fields of Knowledge, a zoomable map allowing the academic disciplines and sub-disciplines in this article be visualised. Sandoz, R. Interactive Historical Atlas of the Disciplines, University of Geneva
Periodical literature is a category of serial publications that appear in a new edition on a regular schedule. The most familiar example is the magazine published weekly, monthly, or quarterly. Newspapers published daily or weekly, are speaking, a separate category of serial. Other examples of periodicals are newsletters, literary magazines, academic journals, science magazines and comic books; these examples are published and referenced by volume and issue. Volume refers to the number of years the publication has been circulated, issue refers to how many times that periodical has been published during that year. For example, the April 2011 publication of a monthly magazine first published in 2002 would be listed as, "volume 10, issue 4". Roman numerals are sometimes used in reference to the volume number; when citing a work in a periodical, there are standardized formats such as The Chicago Manual of Style. In the latest edition of this style, a work with volume number 17 and issue number 3 may be written as follows: James M. Heilman, Andrew G. West.
"Wikipedia and Medicine: Quantifying Readership and the Significance of Natural Language." Journal of Medical Internet Research 17, no. 3. Doi:10.2196/jmir.4069. Periodicals are classified as either popular or scholarly. Popular periodicals are magazines. Scholarly journals are most found in libraries and databases. Examples are the Journal of Social Work. Trade magazines are examples of periodicals, they are written for an audience of professionals in the world. As of the early 1990s, there were over 6,000 academic, scientific and trade publications in the United States alone; these examples are related to the idea of an indefinitely continuing cycle of production and publication: magazines plan to continue publishing, not to stop after a predetermined number of editions. A novel, in contrast, might be published in monthly parts, a method revived after the success of The Pickwick Papers by Charles Dickens; this approach is called part-publication when each part is from a whole work, or a serial, for example in comic books.
It flourished during the nineteenth century, for example with Abraham John Valpy's Delphin Classics, was not restricted to fiction. The International Standard Serial Number is to serial publications what the International Standard Book Number is to books: a standardized reference number. Postal services carry periodicals at a preferential rate. Partwork
A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge. However, in quantum physics, organic chemistry, biochemistry, the term molecule is used less also being applied to polyatomic ions. In the kinetic theory of gases, the term molecule is used for any gaseous particle regardless of its composition. According to this definition, noble gas atoms are considered molecules as they are monatomic molecules. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, as with oxygen. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are not considered single molecules. Molecules as components of matter are common in organic substances, they make up most of the oceans and atmosphere. However, the majority of familiar solid substances on Earth, including most of the minerals that make up the crust and core of the Earth, contain many chemical bonds, but are not made of identifiable molecules.
No typical molecule can be defined for ionic crystals and covalent crystals, although these are composed of repeating unit cells that extend either in a plane or three-dimensionally. The theme of repeated unit-cellular-structure holds for most condensed phases with metallic bonding, which means that solid metals are not made of molecules. In glasses, atoms may be held together by chemical bonds with no presence of any definable molecule, nor any of the regularity of repeating units that characterizes crystals; the science of molecules is called molecular chemistry or molecular physics, depending on whether the focus is on chemistry or physics. Molecular chemistry deals with the laws governing the interaction between molecules that results in the formation and breakage of chemical bonds, while molecular physics deals with the laws governing their structure and properties. In practice, this distinction is vague. In molecular sciences, a molecule consists of a stable system composed of two or more atoms.
Polyatomic ions may sometimes be usefully thought of as electrically charged molecules. The term unstable molecule is used for reactive species, i.e. short-lived assemblies of electrons and nuclei, such as radicals, molecular ions, Rydberg molecules, transition states, van der Waals complexes, or systems of colliding atoms as in Bose–Einstein condensate. According to Merriam-Webster and the Online Etymology Dictionary, the word "molecule" derives from the Latin "moles" or small unit of mass. Molecule – "extremely minute particle", from French molécule, from New Latin molecula, diminutive of Latin moles "mass, barrier". A vague meaning at first; the definition of the molecule has evolved. Earlier definitions were less precise, defining molecules as the smallest particles of pure chemical substances that still retain their composition and chemical properties; this definition breaks down since many substances in ordinary experience, such as rocks and metals, are composed of large crystalline networks of chemically bonded atoms or ions, but are not made of discrete molecules.
Molecules are held together by ionic bonding. Several types of non-metal elements exist only as molecules in the environment. For example, hydrogen only exists as hydrogen molecule. A molecule of a compound is made out of two or more elements. A covalent bond is a chemical bond; these electron pairs are termed shared pairs or bonding pairs, the stable balance of attractive and repulsive forces between atoms, when they share electrons, is termed covalent bonding. Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions, is the primary interaction occurring in ionic compounds; the ions are atoms that have lost one or more electrons and atoms that have gained one or more electrons. This transfer of electrons is termed electrovalence in contrast to covalence. In the simplest case, the cation is a metal atom and the anion is a nonmetal atom, but these ions can be of a more complicated nature, e.g. molecular ions like NH4+ or SO42−. An ionic bond is the transfer of electrons from a metal to a non-metal for both atoms to obtain a full valence shell.
Most molecules are far too small to be seen with the naked eye. DNA, a macromolecule, can reach macroscopic sizes, as can molecules of many polymers. Molecules used as building blocks for organic synthesis have a dimension of a few angstroms to several dozen Å, or around one billionth of a meter. Single molecules cannot be observed by light, but small molecules and the outlines of individual atoms may be traced in some circumstances by use of an atomic force microscope; some of the largest molecules are supermolecules. The smallest molecule is the diatomic hydrogen, with a bond length of 0.74 Å. Effective molecular radius is the size; the table of permselectivity for different substances contains examples. The chemical formula for a molecule uses one line of chemical element symbols and sometimes al
Chemistry is the scientific discipline involved with elements and compounds composed of atoms and ions: their composition, properties and the changes they undergo during a reaction with other substances. In the scope of its subject, chemistry occupies an intermediate position between physics and biology, it is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant chemistry, the formation of igneous rocks, how atmospheric ozone is formed and how environmental pollutants are degraded, the properties of the soil on the moon, how medications work, how to collect DNA evidence at a crime scene. Chemistry addresses topics such as how atoms and molecules interact via chemical bonds to form new chemical compounds. There are four types of chemical bonds: covalent bonds, in which compounds share one or more electron; the word chemistry comes from alchemy, which referred to an earlier set of practices that encompassed elements of chemistry, philosophy, astronomy and medicine.
It is seen as linked to the quest to turn lead or another common starting material into gold, though in ancient times the study encompassed many of the questions of modern chemistry being defined as the study of the composition of waters, growth, disembodying, drawing the spirits from bodies and bonding the spirits within bodies by the early 4th century Greek-Egyptian alchemist Zosimos. An alchemist was called a'chemist' in popular speech, the suffix "-ry" was added to this to describe the art of the chemist as "chemistry"; the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία; this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, in turn derived from the word Kemet, the ancient name of Egypt in the Egyptian language. Alternately, al-kīmīā may derive from χημεία, meaning "cast together"; the current model of atomic structure is the quantum mechanical model. Traditional chemistry starts with the study of elementary particles, molecules, metals and other aggregates of matter.
This matter can be studied in isolation or in combination. The interactions and transformations that are studied in chemistry are the result of interactions between atoms, leading to rearrangements of the chemical bonds which hold atoms together; such behaviors are studied in a chemistry laboratory. The chemistry laboratory stereotypically uses various forms of laboratory glassware; however glassware is not central to chemistry, a great deal of experimental chemistry is done without it. A chemical reaction is a transformation of some substances into one or more different substances; the basis of such a chemical transformation is the rearrangement of electrons in the chemical bonds between atoms. It can be symbolically depicted through a chemical equation, which involves atoms as subjects; the number of atoms on the left and the right in the equation for a chemical transformation is equal. The type of chemical reactions a substance may undergo and the energy changes that may accompany it are constrained by certain basic rules, known as chemical laws.
Energy and entropy considerations are invariably important in all chemical studies. Chemical substances are classified in terms of their structure, phase, as well as their chemical compositions, they can be analyzed using the tools of e.g. spectroscopy and chromatography. Scientists engaged in chemical research are known as chemists. Most chemists specialize in one or more sub-disciplines. Several concepts are essential for the study of chemistry; the particles that make up matter have rest mass as well – not all particles have rest mass, such as the photon. Matter can be a mixture of substances; the atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space occupied by an electron cloud; the nucleus is made up of positively charged protons and uncharged neutrons, while the electron cloud consists of negatively charged electrons which orbit the nucleus. In a neutral atom, the negatively charged electrons balance out the positive charge of the protons.
The nucleus is dense. The atom is the smallest entity that can be envisaged to retain the chemical properties of the element, such as electronegativity, ionization potential, preferred oxidation state, coordination number, preferred types of bonds to form. A chemical element is a pure substance, composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z; the mass number is the sum of the number of neutrons in a nucleus. Although all the nuclei of all atoms belonging to one element will have the same
Sheldon Lee Cooper, Ph. D. Sc. D. is a fictional character in the CBS television series The Big Bang Theory and its spinoff series Young Sheldon, portrayed by actors Jim Parsons in The Big Bang Theory and Iain Armitage in Young Sheldon. For his portrayal, Parsons has won four Primetime Emmy Awards, a Golden Globe Award, a TCA Award, two Critics' Choice Television Awards; the character's childhood is the focus of Young Sheldon: the series' first season is set in 1989 when nine-year-old prodigy Sheldon has skipped ahead five grades, to start high school alongside his older brother. The adult Sheldon is a senior theoretical physicist at The California Institute of Technology, for the first ten seasons of The Big Bang Theory shares an apartment with his colleague and best friend, Leonard Hofstadter. In season 10, Sheldon moves across the hall with his girlfriend Amy, in the former apartment of Leonard's wife Penny, he has a genius-level IQ, but displays a fundamental lack of social skills, a tenuous understanding of humor, difficulty recognizing irony and sarcasm in other people, although he himself employs them.
He exhibits idiosyncratic behavior and a general lack of humility and toleration. These characteristics provide the majority of the humor involving him, which has caused him to be described as the show's breakout character; some viewers have asserted that Sheldon's personality is consistent with Asperger syndrome and obsessive–compulsive disorder. Co-creator Bill Prady has stated that Sheldon's character was neither conceived nor developed with regard to any of these traits, although Parsons has said that in his opinion, Sheldon "couldn't display more traits" of Asperger's; the character of Sheldon Cooper was inspired by a computer programmer known to series co-creator Bill Prady. He is named in honor of Nobel Prize Laureate Leon Cooper. Chuck Lorre intended Johnny Galecki to play the role, but Galecki thought he would be "better suited" for the character of Leonard. Lorre said that when Jim Parsons auditioned for the role, he was "so startlingly good" that he was asked to reaudition "to make sure he hadn't gotten lucky".
Sheldon is one of four characters to appear in every episode of the series, along with Leonard and Raj. Sheldon was raised in Galveston, Texas along with his elder brother, George Jr. and fraternal twin sister, Missy, by his mother, Mary Cooper, an overtly devout Baptist. Sheldon once got his father fired when he told Mr. Hinckley, a store owner, that George was stealing from the cash register. In Young Sheldon, this is retconned: his father is a football coach, fired from his coaching position in Galveston because he disclosed that other coaches were illegally recruiting players to their school, forcing the family to return to Medford, he does drink beer, but is a loving father, trying to understand his intellectually gifted son. The only member of his family to have encouraged his work in science was his grandfather, whom he cherished and affectionately called "Pop-Pop", who died when Sheldon was five years old. Pop-Pop's loss is what caused Sheldon to despise Christmas when his Christmas wish to bring Pop-Pop back didn't come true.
Sheldon's closest relative is his maternal grandmother whom he affectionately calls "Meemaw", who in turn calls him "Moon Pie". His aunt introduced him to the world of science by giving him medical equipment, "in case his work in physics failed, he'd have a'trade' to fall back on". Sheldon was interested in science from an early age, was a child prodigy, although due to his behavioral quirks and his lack of humility about his superior intellect, he was bullied by classmates and neighbors. Sheldon entered college at the age of eleven, at age fourteen he graduated from college summa cum laude. From he worked on his doctorate, was a visiting professor at the University of Heidelberg in Germany, was the youngest person at the time to receive the Stevenson Award, has appeared on the cover of Journal of Physical Chemistry A. Sheldon is now a theoretical physicist doing research at Caltech, although he stated in Young Sheldon that he couldn't see himself living in California due to their carefree lifestyle.
Sheldon is described as a stereotypical "geek". He is characterized as being intelligent, detail-oriented and disturbing. Despite his intelligence, he displays childlike qualities, such as extreme stubbornness and a lack of common sense, it is claimed by Bernadette that the reason Sheldon is sometimes unpleasant is because the part of his brain that tells him it is wrong to be nasty is "getting a wedgie from the rest of his brain". Although, in season 8's "The Space Probe Disintegration", Sheldon tearfully admits to Leonard that he is aware of his peculiarities and how his behavior comes across; the first four episodes of The Big Bang Theory portray Sheldon inconsistently with respect to his characterization, in which he is depicted as rather witty and sarcastic, flirtatious towards Penny in the pilot episode: according to Prady, the character "began to evolve after episode five or so and became his own th
Mostafa A. El-Sayed is a cited Egyptian chemical physicist, a leading nanoscience researcher, a member of the National Academy of Sciences and a US National Medal of Science laureate, he is known for the spectroscopy rule named after him, the El-Sayed rule. He earned his B. Sc. from Ain Shams University Faculty of Science, Cairo in 1953. El-Sayed earned his doctoral degree from Florida State University working with Michael Kasha, the last student of the legendary G. N. Lewis, he spent time as a researcher at Harvard University, Yale University and the California Institute of Technology before joining the faculty of the University of California at Los Angeles in 1961. He is the Julius Brown Chair and Regents Professor of Chemistry and Biochemistry at the Georgia Institute of Technology, he heads the Laser Dynamics Lab there. El-Sayed is a former editor-in-chief of the Journal of Physical Chemistry. El-Sayed and his research group have contributed to many important areas of physical and materials chemistry research.
El-Sayed's research interests include the use of steady-state and ultra fast laser spectroscopy to understand relaxation and conversion of energy in molecules, in solids, in photosynthetic systems, semiconductor quantum dots and metal nanostructures. The El-Sayed group has been involved in the development of new techniques such as magnetophotonic selection, picosecond Raman spectroscopy and phosphorescence microwave double resonance spectroscopy. A major focus of his lab is on the optical and chemical properties of noble metal nanoparticles and their applications in nanocatalysis and nanomedicine, his lab is known for the development of the gold nanorod technology. Professor El-Sayed has over 500 publications in refereed journals in the areas of spectroscopy, molecular dynamics and nanoscience. Prof. El-Sayed has supervised the research of over 70 PhD students, 35 postdoctoral fellows and 20 visiting professors, several of whom hold key positions in the scientific community. Mostafa El Sayed's son, Ayman El-Sayed, the Professor of Tumour Surgery at the University of California, took part in applying these outcomes on cancerous cells of some animals.
For his work in the area of applying laser spectroscopic techniques to study of properties and behavior on the nanoscale, El-Sayed was elected to the National Academy of Sciences in 1980. In 1989 he received the Tolman Award, in 2002, he won the Irving Langmuir Award in Chemical Physics, he has been the recipient of the 1990 King Faisal International Prize in Sciences, Georgia Tech's highest award, "The Class of 1943 Distinguished Professor", an honorary doctorate of philosophy from the Hebrew University, several other awards including some from the different American Chemical Society local sections. He was a Sherman Fairchild Distinguished Scholar at the California Institute of Technology and an Alexander von Humboldt Senior U. S. Scientist Awardee, he served as editor-in-chief of the Journal of Physical Chemistry from 1980–2004 and has served as the U. S. editor of the International Reviews in Physical Chemistry. He is a Fellow of the American Academy of Arts and Sciences, a member of the American Physical Society, the American Association for the Advancement of Science and the Third World Academy of Science.
Mostafa El-Sayed was awarded the 2007 US National Medal of Science "for his seminal and creative contributions to our understanding of the electronic and optical properties of nanomaterials and to their applications in nanocatalysis and nanomedicine, for his humanitarian efforts of exchange among countries and for his role in developing the scientific leadership of tomorrow." Mostafa was announced to be the recipient of the 2009 Ahmed Zewail prize in molecular sciences. In 2011, he was listed #17 in Thomson-Reuters listing of the Top Chemists of the Past Decade. On June 16, 2015, it was announced that Professor El-Sayed will receive the 2016 Priestley Medal, the American Chemical Society’s highest honor, for his decades-long contributions to chemistry. Intersystem Crossing is a photophysical process involving an isoenergetic radiationless transition between two electronic states having different multiplicities, it results in a vibrationally excited molecular entity in the lower electronic state, which usually decays to its lowest molecular vibrational level.
ISC is forbidden by rules of conservation of angular momentum. As a consequence, ISC occurs on long time scales; however the El-Sayed’s rule states that the rate of intersystem crossing, e.g. from the lowest singlet state to the triplet manifold, is large if the radiationless transition involves a change of molecular orbital type. For example, a singlet could transition to a triplet state, but not to a triplet state and vice versa. Formulated by Prof. Mostafa. A. El-Sayed in the 1960s, this rule found in most photochemistry textbooks is useful in understanding phosphorescence, vibrational relaxation, intersystem crossing, internal conversion and lifetimes of excited states in molecules. El-Sayed, M. A. Acc. Chem. Res. 1968,1,8. Lower, S. K.. A. Chem. Rev. 1966,66,199 Mostafa Amr El-Sayed Biographical References: McMurray, Emily J. Notable Twientieth-Century Scientists, Gale Research, Inc.: New York, 1995. Faculty web page at Georgia Tech Laser Dynamics Lab at Georgia Tech President Bush to laud Georgia Tech’s Mostafa El-Sayed Mostafa El-Sayed praised for, contributions to nanotechnology
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the