Nonlinear Dynamics: The study of systems which respond disproportionately (nonlinearly) to initial conditions or perturbing stimuli. Nonlinear systems may exhibit "chaos" which is classically characterized as sensitive dependence on initial conditions. Chaotic systems, while distinguished from more ordered periodic systems, are not random. When their behavior over time is appropriately displayed (in "phase space"), constraints are evident which are described by "strange attractors". Phase space representations of chaotic systems, or strange attractors, usually reveal fractal (FRACTALS) self-similarity across time scales. Natural, including biological, systems often display nonlinear dynamics and chaos.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.Models, Cardiovascular: Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.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.Models, Neurological: Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Molecular Dynamics Simulation: A computer simulation developed to study the motion of molecules over a period of time.Population Dynamics: The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.Contract Services: Outside services provided to an institution under a formal financial agreement.Economics, Hospital: Economic aspects related to the management and operation of a hospital.ColombiaContrast Sensitivity: The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eye disease.Inflation, Economic: An increase in the volume of money and credit relative to available goods resulting in a substantial and continuing rise in the general price level.Students: Individuals enrolled in a school or formal educational program.Herb-Drug Interactions: The effect of herbs, other PLANTS, or PLANT EXTRACTS on the activity, metabolism, or toxicity of drugs.Hepatitis, Infectious Canine: A contagious disease caused by canine adenovirus (ADENOVIRUSES, CANINE) infecting the LIVER, the EYE, the KIDNEY, and other organs in dogs, other canids, and bears. Symptoms include FEVER; EDEMA; VOMITING; and DIARRHEA.Metabolomics: The systematic identification and quantitation of all the metabolic products of a cell, tissue, organ, or organism under varying conditions. The METABOLOME of a cell or organism is a dynamic collection of metabolites which represent its net response to current conditions.Medical Informatics: The field of information science concerned with the analysis and dissemination of medical data through the application of computers to various aspects of health care and medicine.Informatics: The field of information science concerned with the analysis and dissemination of data through the application of computers.Proteomics: The systematic study of the complete complement of proteins (PROTEOME) of organisms.Bibliography as Topic: Discussion of lists of works, documents or other publications, usually with some relationship between them, e.g., by a given author, on a given subject, or published in a given place, and differing from a catalog in that its contents are restricted to holdings of a single collection, library, or group of libraries. (from The ALA Glossary of Library and Information Science, 1983)Bibliography of Medicine: A list of works, documents, and other publications on medical subjects and topics of interest to the field of medicine.Bibliometrics: The use of statistical methods in the analysis of a body of literature to reveal the historical development of subject fields and patterns of authorship, publication, and use. Formerly called statistical bibliography. (from The ALA Glossary of Library and Information Science, 1983)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.Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Stochastic Processes: Processes that incorporate some element of randomness, used particularly to refer to a time series of random variables.Astronomy: The science concerned with celestial bodies and the observation and interpretation of the radiation received in the vicinity of the earth from the component parts of the universe (McGraw Hill Dictionary of Scientific and Technical Terms, 5th ed)Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Noise: Any sound which is unwanted or interferes with HEARING other sounds.Normal Distribution: Continuous frequency distribution of infinite range. Its properties are as follows: 1, continuous, symmetrical distribution with both tails extending to infinity; 2, arithmetic mean, mode, and median identical; and 3, shape completely determined by the mean and standard deviation.Ethmoid Bone: A light and spongy (pneumatized) bone that lies between the orbital part of FRONTAL BONE and the anterior of SPHENOID BONE. Ethmoid bone separates the ORBIT from the ETHMOID SINUS. It consists of a horizontal plate, a perpendicular plate, and two lateral labyrinths.Biotechnology: Body of knowledge related to the use of organisms, cells or cell-derived constituents for the purpose of developing products which are technically, scientifically and clinically useful. Alteration of biologic function at the molecular level (i.e., GENETIC ENGINEERING) is a central focus; laboratory methods used include TRANSFECTION and CLONING technologies, sequence and structure analysis algorithms, computer databases, and gene and protein structure function analysis and prediction.Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Flagella: A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed)Axoneme: A bundle of MICROTUBULES and MICROTUBULE-ASSOCIATED PROTEINS forming the core of each CILIUM or FLAGELLUM. In most eukaryotic cilia or flagella, an axoneme shaft has 20 microtubules arranged in nine doublets and two singlets.Chlamydomonas: A genus GREEN ALGAE in the order VOLVOCIDA. It consists of solitary biflagellated organisms common in fresh water and damp soil.Pubic Bone: A bone that forms the lower and anterior part of each side of the hip bone.Solar Activity: Any type of variation in the appearance of energy output of the sun. (NASA Thesaurus, 1994)Coriolis Force: The apparent deflection (Coriolis acceleration) of a body in motion with respect to the earth, as seen by an observer on the earth, attributed to a fictitious force (Coriolis force) but actually caused by the rotation of the earth. In a medical context it refers to the physiological effects (nausea, vertigo, dizziness, etc.) felt by a person moving radially in a rotating system, as a rotating space station. (From Random House Unabridged Dictionary, 2d ed & McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Cosmic Radiation: High-energy radiation or particles from extraterrestrial space that strike the earth, its atmosphere, or spacecraft and may create secondary radiation as a result of collisions with the atmosphere or spacecraft.Breech Presentation: A malpresentation of the FETUS at near term or during OBSTETRIC LABOR with the fetal cephalic pole in the fundus of the UTERUS. There are three types of breech: the complete breech with flexed hips and knees; the incomplete breech with one or both hips partially or fully extended; the frank breech with flexed hips and extended knees.Version, Fetal: The artificial alteration of the fetal position to facilitate birth.Heart Rate, Fetal: The heart rate of the FETUS. The normal range at term is between 120 and 160 beats per minute.Cardiotocography: Monitoring of FETAL HEART frequency before birth in order to assess impending prematurity in relation to the pattern or intensity of antepartum UTERINE CONTRACTION.Fetal Monitoring: Physiologic or biochemical monitoring of the fetus. It is usually done during LABOR, OBSTETRIC and may be performed in conjunction with the monitoring of uterine activity. It may also be performed prenatally as when the mother is undergoing surgery.Natural Science Disciplines: The sciences dealing with processes observable in nature.Literature, ModernHumanitiesEducational Measurement: The assessing of academic or educational achievement. It includes all aspects of testing and test construction.Gas PoisoningNeurosciences: The scientific disciplines concerned with the embryology, anatomy, physiology, biochemistry, pharmacology, etc., of the nervous system.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Local Area Networks: Communications networks connecting various hardware devices together within or between buildings by means of a continuous cable or voice data telephone system.Posters as Topic: Single or multi-sheet notices made to attract attention to events, activities, causes, goods, or services. They are for display, usually in a public place and are chiefly pictorial.Water: A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Chagas Cardiomyopathy: A disease of the CARDIAC MUSCLE developed subsequent to the initial protozoan infection by TRYPANOSOMA CRUZI. After infection, less than 10% develop acute illness such as MYOCARDITIS (mostly in children). The disease then enters a latent phase without clinical symptoms until about 20 years later. Myocardial symptoms of advanced CHAGAS DISEASE include conduction defects (HEART BLOCK) and CARDIOMEGALY.Trypanosoma cruzi: The agent of South American trypanosomiasis or CHAGAS DISEASE. Its vertebrate hosts are man and various domestic and wild animals. Insects of several species are vectors.Trypanocidal Agents: Agents destructive to the protozoal organisms belonging to the suborder TRYPANOSOMATINA.Outpatients: Persons who receive ambulatory care at an outpatient department or clinic without room and board being provided.Gram-Negative Anaerobic Straight, Curved, and Helical Rods: A group of anaerobic, rod-shaped bacteria that show up as pink (negative) when treated by the Gram-staining method.Metalloexopeptidases: EXOPEPTIDASES which use a metal such as ZINC in the catalytic mechanism.Portraits as Topic: Graphic representations, especially of the face, of real persons, usually posed, living or dead. (From Thesaurus for Graphic Materials II, p540, 1995)History, 17th Century: Time period from 1601 through 1700 of the common era.Optics and Photonics: A specialized field of physics and engineering involved in studying the behavior and properties of light and the technology of analyzing, generating, transmitting, and manipulating ELECTROMAGNETIC RADIATION in the visible, infrared, and ultraviolet range.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.Computer Security: Protective measures against unauthorized access to or interference with computer operating systems, telecommunications, or data structures, especially the modification, deletion, destruction, or release of data in computers. It includes methods of forestalling interference by computer viruses or so-called computer hackers aiming to compromise stored data.ArchivesBiological Science Disciplines: All of the divisions of the natural sciences dealing with the various aspects of the phenomena of life and vital processes. The concept includes anatomy and physiology, biochemistry and biophysics, and the biology of animals, plants, and microorganisms. It should be differentiated from BIOLOGY, one of its subdivisions, concerned specifically with the origin and life processes of living organisms.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.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.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)Forestry: The science of developing, caring for, or cultivating forests.Aircraft: A weight-carrying structure for navigation of the air that is supported either by its own buoyancy or by the dynamic action of the air against its surfaces. (Webster, 1973)Robotics: The application of electronic, computerized control systems to mechanical devices designed to perform human functions. Formerly restricted to industry, but nowadays applied to artificial organs controlled by bionic (bioelectronic) devices, like automated insulin pumps and other prostheses.Man-Machine Systems: A system in which the functions of the man and the machine are interrelated and necessary for the operation of the system.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.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)Blogging: Using an INTERNET based personal journal which may consist of reflections, comments, and often hyperlinks.BooksSocial Work: The use of community resources, individual case work, or group work to promote the adaptive capacities of individuals in relation to their social and economic environments. It includes social service agencies.Portal Vein: A short thick vein formed by union of the superior mesenteric vein and the splenic vein.Life Change Events: Those occurrences, including social, psychological, and environmental, which require an adjustment or effect a change in an individual's pattern of living.Diet: Regular course of eating and drinking adopted by a person or animal.Menu PlanningCaloric Restriction: Reduction in caloric intake without reduction in adequate nutrition. In experimental animals, caloric restriction has been shown to extend lifespan and enhance other physiological variables.Bioelectric Energy Sources: Electric power supply devices which convert biological energy, such as chemical energy of metabolism or mechanical energy of periodic movements, into electrical energy.Methanol: A colorless, flammable liquid used in the manufacture of FORMALDEHYDE and ACETIC ACID, in chemical synthesis, antifreeze, and as a solvent. Ingestion of methanol is toxic and may cause blindness.Electricity: The physical effects involving the presence of electric charges at rest and in motion.