Insectivore Organism which eats insects An insectivore is a carnivorous plant or animal that eats insects.[1] An alternative term is entomophage,[2] which also refers to the human practice of eating insects. The first vertebrate insectivores were amphibians. Although individually small, insects exist in enormous numbers. Examples[edit] Examples of insectivores include different kinds of species of carp, opossum, frogs, lizards (e.g. chameleons, geckos), nightingales, swallows, echidnas,[6] numbats, anteaters, armadillos, aardvarks, pangolins, aardwolfs,[7] bats, and spiders. Insectivorous plants[edit] Insectivorous plants are plants that derive some of their nutrients from trapping and consuming animals or protozoan. Insectivorous plants might consume insects and other animal material trapped adventitiously, though most species to which such food represents an important part of their intake are specifically, often spectacularly, adapted to attract and secure adequate supplies. See also[edit]
Lattice (group) In mathematics, especially in geometry and group theory, a lattice in is a discrete subgroup of which spans the real vector space . Every lattice in A lattice is the symmetry group of discrete translational symmetry in n directions. A lattice in the sense of a 3-dimensional array of regularly spaced points coinciding with e.g. the atom or molecule positions in a crystal, or more generally, the orbit of a group action under translational symmetry, is a translate of the translation lattice: a coset, which need not contain the origin, and therefore need not be a lattice in the previous sense. A simple example of a lattice in is the subgroup . , and the Leech lattice in . is central to the study of elliptic functions, developed in nineteenth century mathematics; it generalises to higher dimensions in the theory of abelian functions. A typical lattice in thus has the form where {v1, ..., vn} is a basis for . See also: Integer points in polyhedra Five lattices in the Euclidean plane A lattice in .
Pharyngeal jaw The pharyngeal jaws of the moray eel Pharyngeal jaws are a "second set" of jaws contained within an animal's throat, or pharynx, distinct from the primary or oral jaws. They are believed to have originated as modified gill arches, in much the same way as oral jaws. Cichlids[edit] Moray eels[edit] Most fish species with pharyngeal teeth do not have extendable pharyngeal jaws. Popular culture[edit] References[edit] External links[edit] Rotational symmetry Generally speaking, an object with rotational symmetry, also known in biological contexts as radial symmetry, is an object that looks the same after a certain amount of rotation. An object may have more than one rotational symmetry; for instance, if reflections or turning it over are not counted. The degree of rotational symmetry is how many degrees the shape has to be turned to look the same on a different side or vertex. It can not be the same side or vertex. Formal treatment[edit] Symmetry with respect to all rotations about all points implies translational symmetry with respect to all translations, so space is homogeneous, and the symmetry group is the whole E(m). Laws of physics are SO(3)-invariant if they do not distinguish different directions in space. n-fold rotational symmetry[edit] The notation for n-fold symmetry is Cn or simply "n". The fundamental domain is a sector of 360°/n. Examples without additional reflection symmetry: Examples[edit] See also[edit] References[edit]
Moscow–Washington hotline Direct communication system between Russia and the United States The Kremlin in Moscow, Russia (left) and the Pentagon in Arlington County, Virginia, U.S. (right), the two facilities linked by the hotline. The Moscow–Washington hotline (formally known in the United States as the Washington–Moscow Direct Communications Link;[1] Russian: Горячая линия Вашингтон — Москва, tr. Origins[edit] Background[edit] The 1962 Cuban Missile Crisis made the hotline a priority. During the crisis, the United States took nearly twelve hours to receive and decode Nikita Khrushchev's 3,000-word initial settlement message – a dangerously long time. Agreement[edit] The "hotline", as it would come to be known, was established after the signing of a "Memorandum of Understanding Regarding the Establishment of a Direct Communications Line" on June 20, 1963, in Geneva, Switzerland, by representatives of the Soviet Union and the United States.[3] Technical details: United States[edit] The hotline was tested hourly.
Lorentz covariance In physics, Lorentz symmetry, named for Hendrik Lorentz, is "the feature of nature that says experimental results are independent of the orientation or the boost velocity of the laboratory through space".[1] Lorentz covariance, a related concept, is a key property of spacetime following from the special theory of relativity. Lorentz covariance has two distinct, but closely related meanings: This usage of the term covariant should not be confused with the related concept of a covariant vector. Local Lorentz covariance, which follows from general relativity, refers to Lorentz covariance applying only locally in an infinitesimal region of spacetime at every point. Examples[edit] In general, the nature of a Lorentz tensor can be identified by its tensor order, which is the number of indices it has. Please note, the metric sign convention such that η = diag (1, −1, −1, −1) is used throughout the article. Scalars[edit] Spacetime interval: Proper time (for timelike intervals): Rest mass: 4-velocity:
Vaporetto Vaporetto on the Canal Grande in Venice. Venice Vaporetto water bus system – water bus and bus stop The vaporetto is a Venetian public waterbus. There are 19 scheduled lines[1] that serve locales within Venice, and travel between Venice and nearby islands, such as Murano, Burano, and Lido. The name, vaporetto, could be translated as "little steamer", and refers to similarly purposed ships in the past that were run by steam. The natives call the vaporetto batèlo or vaporino. Three vaporetti carrying passengers ACTV sells 12-, 24-, 36-, 48- and 72-hour passes as well as single-journey tickets and 7-day passes.[3] The private express company Alilaguna also operates a limited water bus service, to the airport for example, although its boats (including a new one that is a hybrid electric/diesel) are not technically considered to be vaporetti.[4] The first vaporetto appeared in 1881, in competition with gondoliers and hotel boatmen. Notes[edit] External links[edit]
Symmetry Sphere symmetrical group o representing an octahedral rotational symmetry. The yellow region shows the fundamental domain. Symmetry (from Greek συμμετρία symmetria "agreement in dimensions, due proportion, arrangement")[1] has two meanings. The first is a vague sense of harmonious and beautiful proportion and balance.[2][3] The second is an exact mathematical "patterned self-similarity" that can be demonstrated with the rules of a formal system, such as geometry or physics. Although these two meanings of "symmetry" can sometimes be told apart, they are related, so they are here discussed together.[3] Mathematical symmetry may be observed This article describes these notions of symmetry from four perspectives. The opposite of symmetry is asymmetry. Geometry[edit] A geometric object is typically symmetric only under a subgroup of isometries. Reflectional symmetry[edit] An isosceles triangle with mirror symmetry. A drawing of a butterfly with bilateral symmetry Rotational symmetry[edit] .
Dewey Decimal Classification Library classification system A library book shelf in Hong Kong classified using the New Classification Scheme for Chinese Libraries, an adaptation of the Dewey Classification Scheme The Dewey Decimal Classification (DDC), colloquially the Dewey Decimal System, is a proprietary library classification system first published in the United States by Melvil Dewey in 1876.[1] Originally described in a four-page pamphlet, it has been expanded to multiple volumes and revised through 23 major editions, the latest printed in 2011. It is also available in an abridged version suitable for smaller libraries. OCLC, a non-profit cooperative that serves libraries, currently maintains the system and licenses online access to WebDewey, a continuously updated version for catalogers. The Decimal Classification introduced the concepts of relative location and relative index which allow new books to be added to a library in their appropriate location based on subject. History[edit] Design[edit] 510 Mathematics
Quantum Diaries We’ve been discussing the Higgs (its interactions, its role in particle mass, and its vacuum expectation value) as part of our ongoing series on understanding the Standard Model with Feynman diagrams. Now I’d like to take a post to discuss a very subtle feature of the Standard Model: its chiral structure and the meaning of “mass.” This post is a little bit different in character from the others, but it goes over some very subtle features of particle physics and I would really like to explain them carefully because they’re important for understanding the entire scaffolding of the Standard Model. My goal is to explain the sense in which the Standard Model is “chiral” and what that means. In order to do this, we’ll first learn about a related idea, helicity, which is related to a particle’s spin. Helicity Fact: every matter particle (electrons, quarks, etc.) is spinning, i.e. each matter particle carries some intrinsic angular momentum. This is our spinning particle. Sounds good? Chirality
Cheat sheet A cheat sheet (also cheatsheet) or crib sheet is a concise set of notes used for quick reference. A cheat sheet is a physical piece of paper, often filled with equations and/or facts in compressed writing. Students often print cheat sheets in extremely small font, fitting an entire page of notes in the palm of their hands during the exam. Crib sheets are also fully worked solutions for exams or work sheets normally handed out to university staff in order to ease marking (grading). As reference cards[edit] In more general usage, a crib sheet is any short (one- or two-page) reference to terms, commands, or symbols where the user is expected to understand the use of such terms but not necessarily to have memorized all of them. Some academic and technical publishers also publish crib sheets for software packages and technical topics. See also[edit] References[edit] External links[edit] The dictionary definition of cheat sheet at Wiktionary
Sharkcano: Exploring The Relationship Between Underwater Volcanoes And Sharks Back in 2015, a video of hammerheads and silky sharks swimming around in an underwater volcano, in sizzling water temperatures and elevated acidity levels, went viral. Dubbed “sharkcano,” people wondered if there were any places sharks couldn’t survive. (Spoiler alert: there are a few, like Mount Everest and your backyard pool.) The sharks (and a sixgill stingray!) were first found inside the volcano caldera by Brennan Phillips five years ago following the eruption of submarine volcano Kavachi, which has built itself above sea level at least nine times since 1950. Located in the Solomon Islands (south of Gatokae and Vangunu islands), it is known as one of the most active underwater volcanoes in the Pacific Ocean even though it has rarely been observed. More than 70 percent of all volcanic eruptions occur underwater but researchers know very little when it comes to understanding underwater volcano behavior.