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A variety of tweezers
Network topology is the arrangement of the various elements ( links , nodes , etc.) of a computer [ 1 ] [ 2 ] or biological network . [ 3 ] Essentially, it is the topological [ 4 ] structure of a network, and may be depicted physically or logically. Physical topology refers to the placement of the network's various components, including device location and cable installation, while logical topology shows how data flows within a network, regardless of its physical design. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ between two networks, yet their topologies may be identical. A good example is a local area network (LAN): Any given node in the LAN has one or more physical links to other devices in the network; graphically mapping these links results in a geometric shape that can be used to describe the physical topology of the network.
A tag cloud with terms related to Web 2.0 A tag cloud ( word cloud , or weighted list in visual design) is a visual representation for text data, typically used to depict keyword metadata (tags) on websites, or to visualize free form text. Tags are usually single words, and the importance of each tag is shown with font size or color. [ 1 ] This format is useful for quickly perceiving the most prominent terms and for locating a term alphabetically to determine its relative prominence. When used as website navigation aids, the terms are hyperlinked to items associated with the tag. [ edit ] History In the language of visual design, a tag cloud (or word cloud) is one kind of "weighted list", as commonly used on geographic maps to represent the relative size of cities in terms of relative typeface size.
In linear algebra , an orthogonal matrix is a square matrix with real entries whose columns and rows are orthogonal unit vectors (i.e., orthonormal vectors). Equivalently, a matrix Q is orthogonal if its transpose is equal to its inverse : which entails where I is the identity matrix . An orthogonal matrix Q is necessarily invertible (with inverse Q −1 = Q T ), unitary ( Q −1 = Q * ), and normal ( Q * Q = QQ * ).
Illustration of electrophoresis Illustration of electrophoresis retardation Electrophoresis is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field . [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] [ 6 ] This electrokinetic phenomenon was observed for the first time in 1807 by Ferdinand Frederic Reuss ( Moscow State University ), [ 7 ] who noticed that the application of a constant electric field caused clay particles dispersed in water to migrate.
A glossary , also known as an vocabulary , or clavis , is an alphabetical list of terms in a particular domain of knowledge with the definitions for those terms. Traditionally, a glossary appears at the end of a book and includes terms within that book that are either newly introduced, uncommon, or specialized. A bilingual glossary is a list of terms in one language defined in a second language or glossed by synonyms (or at least near-synonyms) in another language.
The original meaning of the word shuttle is the device used in weaving to carry the weft. By reference to the continual to-and-fro motion associated with that, the term was then applied in transportation and then in other spheres. Thus the word may now also refer to:
Hub , or Hubs may refer to: [ edit ] Wheels Bicycle hub , the central part of a bicycle wheel Locking hubs , accessory on four-wheel drive vehicles Wheel hub assembly , an automotive part [ edit ] Buildings
A web is a silken structure created by a spider. Web may also refer to: [ edit ] Computing World Wide Web or "the Web", a hypertext system that operates over the Internet Web 2.0 , a perceived transition of the Web from a collection of Web sites to a full-fledged computing platform serving Web applications WorldWideWeb , the first web browser and editor Web (web browser) , the web browser included with GNOME desktop environment (previously known as Epiphany ) Web.com , a public company that offers websites and other services for small businesses and consumers Webs (web hosting) , a website which allows users to create free websites WEB , a computer programming system created by Donald Knuth to implement literate programming
In biochemistry and structural biology , secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids (DNA/RNA). It does not, however, describe specific atomic positions in three-dimensional space, which are considered to be tertiary structure . Secondary structure can be formally defined by the hydrogen bonds of the biopolymer, as observed in an atomic-resolution structure.
In computer science , a lookup table is an array that replaces runtime computation with a simpler array indexing operation. The savings in terms of processing time can be significant, since retrieving a value from memory is often faster than undergoing an 'expensive' computation or input/output operation. [ 1 ] The tables may be precalculated and stored in static program storage, calculated (or "pre-fetched" ) as part of a program's initialization phase ( memoization ), or even stored in hardware in application-specific platforms. Lookup tables are also used extensively to validate input values by matching against a list of valid (or invalid) items in an array and, in some programming languages, may include pointer functions (or offsets to labels) to process the matching input.
A tumor suppressor gene , or anti-oncogene , is a gene that protects a cell from one step on the path to cancer. When this gene is mutated to cause a loss or reduction in its function, the cell can progress to cancer, usually in combination with other genetic changes. [ edit ] Two-hit hypothesis
Phosphatase and tensin homolog ( PTEN ) is a protein that, in humans, is encoded by the PTEN gene . [ 2 ] Mutations of this gene are a step in the development of many cancers . PTEN acts as a tumor suppressor gene through the action of its phosphatase protein product. This phosphatase is involved in the regulation of the cell cycle , preventing cells from growing and dividing too rapidly. [ 3 ] It is one of the targets of an oncomiR, MIRN21 . This gene was identified as a tumor suppressor that is mutated in a large number of cancers at high frequency.
The Sun is Earth's primary source of light. About 44% of the sun's electromagnetic radiation that reaches the ground is in the visible light range. Visible light (commonly referred to simply as light ) is electromagnetic radiation that is visible to the human eye , and is responsible for the sense of sight . [ 1 ] Visible light has a wavelength in the range of about 380 nanometres to about 740 nm – between the invisible infrared , with longer wavelengths and the invisible ultraviolet , with shorter wavelengths. Primary properties of visible light are intensity , propagation direction, frequency or wavelength spectrum , and polarisation , while its speed in a vacuum, 299,792,458 meters per second, is one of the fundamental constants of nature. Visible light, as with all types of electromagnetic radiation (EMR), is experimentally found to always move at this speed in vacuum.
From Wikipedia, the free encyclopedia Rate (mathematics) , a specific kind of ratio, in which two measurements are related to each other Rate of travel, or velocity Naval rating or rate, terms used to designate specialty or seniority of enlisted naval personnel. Rate of a ship , a term indicating a sail ship's firepower in the British Royal Navy Bit rate , number of bits that are conveyed or processed per unit of time Rates , a Portuguese parish and town located in the municipality of Póvoa de Varzim In science and finance