Fractals: Patterns (real or mathematical) which look similar at different scales, for example the network of airways in the lung which shows similar branching patterns at progressively higher magnifications. Natural fractals are self-similar across a finite range of scales while mathematical fractals are the same across an infinite range. Many natural, including biological, structures are fractal (or fractal-like). Fractals are related to "chaos" (see NONLINEAR DYNAMICS) in that chaotic processes can produce fractal structures in nature, and appropriate representations of chaotic processes usually reveal self-similarity over time.Physics: The study of those aspects of energy and matter in terms of elementary principles and laws. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Quantum Dots: Nanometer sized fragments of semiconductor crystalline material which emit PHOTONS. The wavelength is based on the quantum confinement size of the dot. They can be embedded in MICROBEADS for high throughput ANALYTICAL CHEMISTRY TECHNIQUES.Quantum Theory: The theory that the radiation and absorption of energy take place in definite quantities called quanta (E) which vary in size and are defined by the equation E=hv in which h is Planck's constant and v is the frequency of the radiation.Benchmarking: Method of measuring performance against established standards of best practice.Jupiter: The fifth planet in order from the sun. It is one of the five outer planets of the solar system. Its sixteen natural satellites include Callisto, Europa, Ganymede, and Io.Extraterrestrial Environment: The environment outside the earth or its atmosphere. The environment may refer to a closed cabin (such as a space shuttle or space station) or to space itself, the moon, or other planets.Uranus: The seventh planet in order from the sun. It is one of the five outer planets of the solar system. It has five known natural satellites.Neptune: The eighth planet in order from the sun. It is one of the five outer planets of the solar system. Its two natural satellites are Nereid and Triton.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Copyright: It is a form of protection provided by law. In the United States this protection is granted to authors of original works of authorship, including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. (from Circular of the United States Copyright Office, 6/30/2008)Directories as Topic: Lists of persons or organizations, systematically arranged, usually in alphabetic or classed order, giving address, affiliations, etc., for individuals, and giving address, officers, functions, and similar data for organizations. (ALA Glossary of Library and Information Science, 1983)Feathers: Flat keratinous structures found on the skin surface of birds. Feathers are made partly of a hollow shaft fringed with barbs. They constitute the plumage.Birds: Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.Cell Nucleus Size: The quantity of volume or surface area of a CELL NUCLEUS.Passeriformes: A widely distributed order of perching BIRDS, including more than half of all bird species.Animal Migration: Periodic movements of animals in response to seasonal changes or reproductive instinct. Hormonal changes are the trigger in at least some animals. Most migrations are made for reasons of climatic change, feeding, or breeding.Songbirds: PASSERIFORMES of the suborder, Oscines, in which the flexor tendons of the toes are separate, and the lower syrinx has 4 to 9 pairs of tensor muscles inserted at both ends of the tracheal half rings. They include many commonly recognized birds such as CROWS; FINCHES; robins; SPARROWS; and SWALLOWS.DimethoxyphenylethylamineSmegmamorpha: Group of fish under the superorder Acanthopterygii, separate from the PERCIFORMES, which includes swamp eels, mullets, sticklebacks, seahorses, spiny eels, rainbowfishes, and KILLIFISHES. The name is derived from the six taxa which comprise the group. (From, 8/4/2000)Anatomy, Comparative: The comparative study of animal structure with regard to homologous organs or parts. (Stedman, 25th ed)Anthropology, Medical: Field of social science that is concerned with differences between human groups as related to health status and beliefs.Military ScienceHistory, Medieval: The period of history from the year 500 through 1450 of the common era.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Models, Genetic: Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Computational Biology: A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories for solving biological problems including manipulation of models and datasets.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Synthetic Biology: A field of biological research combining engineering in the formulation, design, and building (synthesis) of novel biological structures, functions, and systems.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Bioengineering: The application of engineering principles and methods to living organisms or biological systems.Genetic Engineering: Directed modification of the gene complement of a living organism by such techniques as altering the DNA, substituting genetic material by means of a virus, transplanting whole nuclei, transplanting cell hybrids, etc.Journal Impact Factor: A quantitative measure of the frequency on average with which articles in a journal have been cited in a given period of time.Artificial Cells: Chemically synthesized structures which functionally resemble natural cells.Artificial Intelligence: Theory and development of COMPUTER SYSTEMS which perform tasks that normally require human intelligence. Such tasks may include speech recognition, LEARNING; VISUAL PERCEPTION; MATHEMATICAL COMPUTING; reasoning, PROBLEM SOLVING, DECISION-MAKING, and translation of language.Intelligence: The ability to learn and to deal with new situations and to deal effectively with tasks involving abstractions.Expert Systems: Computer programs based on knowledge developed from consultation with experts on a problem, and the processing and/or formalizing of this knowledge using these programs in such a manner that the problems may be solved.Fuzzy Logic: Approximate, quantitative reasoning that is concerned with the linguistic ambiguity which exists in natural or synthetic language. At its core are variables such as good, bad, and young as well as modifiers such as more, less, and very. These ordinary terms represent fuzzy sets in a particular problem. Fuzzy logic plays a key role in many medical expert systems.Neural Networks (Computer): A computer architecture, implementable in either hardware or software, modeled after biological neural networks. Like the biological system in which the processing capability is a result of the interconnection strengths between arrays of nonlinear processing nodes, computerized neural networks, often called perceptrons or multilayer connectionist models, consist of neuron-like units. A homogeneous group of units makes up a layer. These networks are good at pattern recognition. They are adaptive, performing tasks by example, and thus are better for decision-making than are linear learning machines or cluster analysis. They do not require explicit programming.Games, Experimental: Games designed to provide information on hypotheses, policies, procedures, or strategies.Electromagnetic Fields: Fields representing the joint interplay of electric and magnetic forces.Electronics: The study, control, and application of the conduction of ELECTRICITY through gases or vacuum, or through semiconducting or conducting materials. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Electromagnetic Phenomena: Characteristics of ELECTRICITY and magnetism such as charged particles and the properties and behavior of charged particles, and other phenomena related to or associated with electromagnetism.Venereal Tumors, Veterinary: Tumors most commonly seen on or near the genitalia. They are venereal, most likely transmitted through transplantation of cells by contact. Metastases have been reported. Spontaneous regression may occur.Reminder Systems: Systems used to prompt or aid the memory. The systems can be computerized reminders, color coding, telephone calls, or devices such as letters and postcards.Electromagnetic Radiation: Waves of oscillating electric and MAGNETIC FIELDS which move at right angles to each other and outward from the source.PubMed: A bibliographic database that includes MEDLINE as its primary subset. It is produced by the National Center for Biotechnology Information (NCBI), part of the NATIONAL LIBRARY OF MEDICINE. PubMed, which is searchable through NLM's Web site, also includes access to additional citations to selected life sciences journals not in MEDLINE, and links to other resources such as the full-text of articles at participating publishers' Web sites, NCBI's molecular biology databases, and PubMed Central.BooksPublishing: "The business or profession of the commercial production and issuance of literature" (Webster's 3d). It includes the publisher, publication processes, editing and editors. Production may be by conventional printing methods or by electronic publishing.Retina: The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.MEDLINE: The premier bibliographic database of the NATIONAL LIBRARY OF MEDICINE. MEDLINE® (MEDLARS Online) is the primary subset of PUBMED and can be searched on NLM's Web site in PubMed or the NLM Gateway. MEDLINE references are indexed with MEDICAL SUBJECT HEADINGS (MeSH).