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In metalogic, formal languages are sometimes called object languages. The language used to make statements about an object language is called a metalanguage. This distinction is a key difference between logic and metalogic. While logic deals with proofs in a formal system, expressed in some formal language, metalogic deals with proofs about a formal system which are expressed in a metalanguage about some object language. | https://en.wikipedia.org/wiki/Deductive_science |
In metalogic, the words 'use' and 'mention', in both their noun and verb forms, take on a technical sense in order to identify an important distinction. The use–mention distinction (sometimes referred to as the words-as-words distinction) is the distinction between using a word (or phrase) and mentioning it. Usually it is indicated that an expression is being mentioned rather than used by enclosing it in quotation marks, printing it in italics, or setting the expression by itself on a line. The enclosing in quotes of an expression gives us the name of an expression, for example: 'Metalogic' is the name of this article. This article is about metalogic. | https://en.wikipedia.org/wiki/Deductive_science |
In metals and ceramics, requirements for it being superplastic include a fine grain size (less than approximately 10 micrometers) and an operating temperature that is often from above a half absolute melting point. Several studies have found superplasticity in coarse-grain materials. However, the scientific community has agreed the grain size threshold at 10 micrometers is the precondition for activating superplasticity. Generally, grain growth at high-temperature, therefore maintaining the fine grain size structure at homologous temperature, is the main challenge in superplasticity research. | https://en.wikipedia.org/wiki/Superplastic_deformation |
The typical microstructure strategy uses a fine dispersion of thermally stable particles, which pin the grain boundaries and maintain the fine grain structure at the high temperatures and existence of multiple phases required for superplastic deformation. The alloy's most typical microstructure for superplasticity is eutectic or eutectoid structure, as found in Sn-Pb, or Zn-Alloy alloys. Those materials that meet these parameters must still have a strain rate sensitivity (a measurement of the way the stress on a material reacts to changes in strain rate) of >0.3 to be considered superplastic. The ideal strain rate sensitivity is 0.5, typically found in micro duplex alloys. | https://en.wikipedia.org/wiki/Superplastic_deformation |
In metals and minerals, grains are ordered structures in different crystal orientations. Subgrains are defined as grains that are oriented at a < 10–15 degree angle at the grain boundary, making it a low-angle grain boundary (LAGB). Due to the relationship between the energy versus the number of dislocations at the grain boundary, there is a driving force for fewer high-angle grain boundaries (HAGB) to form and grow instead of a higher number of LAGB. The energetics of the transformation depend on the interfacial energy at the boundaries, the lattice geometry (atomic and planar spacing, structure of the material, and the degrees of freedom of the grains involved (misorientation, inclination). The recrystallized material has less total grain boundary area, which means that failure via brittle fracture along the grain boundary is less probable. | https://en.wikipedia.org/wiki/Subgrain_rotation_recrystallization |
In metals, the Fermi level lies in the conduction band (see Band Theory, above) giving rise to free conduction electrons. However, in semiconductors the position of the Fermi level is within the band gap, about halfway between the conduction band minimum (the bottom of the first band of unfilled electron energy levels) and the valence band maximum (the top of the band below the conduction band, of filled electron energy levels). That applies for intrinsic (undoped) semiconductors. This means that at absolute zero temperature, there would be no free conduction electrons, and the resistance is infinite. | https://en.wikipedia.org/wiki/Complex_resistivity |
However, the resistance decreases as the charge carrier density (i.e., without introducing further complications, the density of electrons) in the conduction band increases. In extrinsic (doped) semiconductors, dopant atoms increase the majority charge carrier concentration by donating electrons to the conduction band or producing holes in the valence band. (A "hole" is a position where an electron is missing; such holes can behave in a similar way to electrons.) | https://en.wikipedia.org/wiki/Complex_resistivity |
For both types of donor or acceptor atoms, increasing dopant density reduces resistance. Hence, highly doped semiconductors behave metallically. At very high temperatures, the contribution of thermally generated carriers dominates over the contribution from dopant atoms, and the resistance decreases exponentially with temperature. | https://en.wikipedia.org/wiki/Complex_resistivity |
In metals, thermal conductivity is approximately correlated with electrical conductivity according to the Wiedemann–Franz law, as freely moving valence electrons transfer not only electric current but also heat energy. However, the general correlation between electrical and thermal conductance does not hold for other materials, due to the increased importance of phonon carriers for heat in non-metals. Highly electrically conductive silver is less thermally conductive than diamond, which is an electrical insulator but conducts heat via phonons due to its orderly array of atoms. | https://en.wikipedia.org/wiki/Thermal_Conductivity |
In metalworking and jewelry making, casting is a process in which a liquid metal is delivered into a mold (usually by a crucible) that contains a negative impression (i.e., a three-dimensional negative image) of the intended shape. The metal is poured into the mold through a hollow channel called a sprue. The metal and mold are then cooled, and the metal part (the casting) is extracted. Casting is most often used for making complex shapes that would be difficult or uneconomical to make by other methods.Casting processes have been known for thousands of years, and have been widely used for sculpture (especially in bronze), jewelry in precious metals, and weapons and tools. | https://en.wikipedia.org/wiki/Mould_cavity |
Highly engineered castings are found in 90 percent of durable goods, including cars, trucks, aerospace, trains, mining and construction equipment, oil wells, appliances, pipes, hydrants, wind turbines, nuclear plants, medical devices, defense products, toys, and more.Traditional techniques include lost-wax casting (which may be further divided into centrifugal casting, and vacuum assist direct pour casting), plaster mold casting and sand casting. The modern casting process is subdivided into two main categories: expendable and non-expendable casting. It is further broken down by the mold material, such as sand or metal, and pouring method, such as gravity, vacuum, or low pressure. | https://en.wikipedia.org/wiki/Mould_cavity |
In metalworking and woodworking, an automatic lathe is a lathe with an automatically controlled cutting process. Automatic lathes were first developed in the 1870s and were mechanically controlled. From the advent of NC and CNC in the 1950s, the term automatic lathe has generally been used for only mechanically controlled lathes, although some manufacturers (e.g., DMG Mori and Tsugami) market Swiss-type CNC lathes as 'automatic'.CNC has not yet entirely displaced mechanically automated lathes, as although no longer in production, many mechanically automated lathes remain in service. | https://en.wikipedia.org/wiki/Automatic_lathe |
In metalworking, a drift pin, drift pin punch, simply drift, is the name for a tool used for localizing a hammer blow. A drift is smaller in diameter than the hammer face, thus concentrating the force into a smaller area. A drift is also used where the surrounding surfaces need to be protected from the hammer blow. A drift is not used as a punch in the traditional sense of the term. | https://en.wikipedia.org/wiki/Drift_pin |
Unlike most punches, force should never be applied to the tip of drift pin. Drifts are constructed from wood, light alloys, copper, or steel which are usually rods cut to size as for the job. Drifts can be used to remove dents from inaccessible places, for striking pins and keys out. | https://en.wikipedia.org/wiki/Drift_pin |
Some drift pins are constructed with a taper, with the hammer acting on the large end of the taper. The tapered drift pin is used to align the two bolt holes in two separate components that are designed to mate. First the two components are maneuvered until the holes in each are in semi-alignment, such that the narrow end of the tapered drift pin can be inserted through the two holes. | https://en.wikipedia.org/wiki/Drift_pin |
The pin is then driven into the two holes forcing them into true alignment, allowing for easy insertion of the fastener. This technique is especially useful for aligning fastener holes in structural steel members, which always have multiple holes, such that when one pair of mating holes comes into alignment, the others in the set are aligned, allowing a fastener, usually a bolt, to be inserted, before the drift pin is removed. In this situation the tapered drift pin is on the handle end of a spud wrench used for assembling trusses, structural steel beams, and steel pipe flanges. A spud wrench is seldom hammered to set the pin in the two holes. | https://en.wikipedia.org/wiki/Drift_pin |
In metalworking, a filler metal is a metal added in the making of a joint through welding, brazing, or soldering. | https://en.wikipedia.org/wiki/Filler_metal |
In metalworking, a knockout punch, also known as a chassis punch, panel punch, Greenlee punch, or a Q-max, is a hand tool used to punch a hole through sheet metal. It is a very simple tool that consists of a punch, die, and screw. There are three different drive systems: manual, ratchet, and hydraulic. | https://en.wikipedia.org/wiki/Knockout_punch |
In metalworking, a welding defect is any flaw that compromises the usefulness of a weldment. There are many different types of welding defects, which are classified according to ISO 6520, while acceptable limits for welds are specified in ISO 5817 and ISO 10042. | https://en.wikipedia.org/wiki/Lamellar_tearing |
In metalworking, a welding joint is a point or edge where two or more pieces of metal or plastic are joined together. They are formed by welding two or more workpieces according to a particular geometry. There are five types of joints referred to by the American Welding Society: butt, corner, edge, lap, and tee. These configurations may have various configurations at the joint where actual welding can occur. | https://en.wikipedia.org/wiki/Cruciform_joint |
In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, and then allowing it to cool and solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting is most often used for making complex shapes that would be difficult or uneconomical to make by other methods. | https://en.wikipedia.org/wiki/Foundry |
In metalworking, crimping is a method of joining two or more pieces of metal or other ductile material by deforming one or both of them to hold the other. The bend or deformity is called the crimp. | https://en.wikipedia.org/wiki/Crimp_(joining) |
In metalworking, forming is the fashioning of metal parts and objects through mechanical deformation; the workpiece is reshaped without adding or removing material, and its mass remains unchanged. Forming operates on the materials science principle of plastic deformation, where the physical shape of a material is permanently deformed. | https://en.wikipedia.org/wiki/Metal_forming |
In metalworking, metal is heated until it becomes liquid and is then poured into a mold. The mold is a hollow cavity that includes the desired shape, but the mold also includes runners and risers that enable the metal to fill the mold. The mold and the metal are then cooled until the metal solidifies. The solidified part (the casting) is then recovered from the mold. Subsequent operations remove excess material caused by the casting process (such as the runners and risers). | https://en.wikipedia.org/wiki/Casting_process |
In metalworking, rolling is a metal forming process in which metal stock is passed through one or more pairs of rolls to reduce the thickness, to make the thickness uniform, and/or to impart a desired mechanical property. The concept is similar to the rolling of dough. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature, then the process is known as hot rolling. | https://en.wikipedia.org/wiki/Rolling_mills |
If the temperature of the metal is below its recrystallization temperature, the process is known as cold rolling. In terms of usage, hot rolling processes more tonnage than any other manufacturing process, and cold rolling processes the most tonnage out of all cold working processes. | https://en.wikipedia.org/wiki/Rolling_mills |
Roll stands holding pairs of rolls are grouped together into rolling mills that can quickly process metal, typically steel, into products such as structural steel (I-beams, angle stock, channel stock), bar stock, and rails. Most steel mills have rolling mill divisions that convert the semi-finished casting products into finished products. There are many types of rolling processes, including ring rolling, roll bending, roll forming, profile rolling, and controlled rolling. | https://en.wikipedia.org/wiki/Rolling_mills |
In metalworking, weld pool commonly refers to the dime-sized workable portion of a weld where the base metal has reached its melting point and is ready to be infused with filler material. The weld pool is central to the success of the welding process. It was first observed in oxy-fuel welding by Fouché & Picard in 1903, after the discovery of acetylene by Edmund Davy in 1836. | https://en.wikipedia.org/wiki/Weld_pool |
The weld pool must be carried along the joint in a consistent width and depth, and the motion used to carry the weld pool has a direct effect on the quality of the weld bead. A weld made by starting and carrying a weld pool, without the addition of a filler material, is called an autogenous weld. == References == | https://en.wikipedia.org/wiki/Weld_pool |
In metaphase I of meiosis I, the pairs of homologous chromosomes, also known as bivalents or tetrads, line up in a random order along the metaphase plate. The random orientation is another way for cells to introduce genetic variation. Meiotic spindles emanating from opposite spindle poles attach to each of the homologs (each pair of sister chromatids) at the kinetochore. | https://en.wikipedia.org/wiki/Homologous_chromosomes |
In metaphase, the centromeres of the chromosomes align themselves on the metaphase plate (or equatorial plate), an imaginary line that is at equal distances from the two centrosome poles and held together by complexes known as cohesins. Chromosomes line up in the middle of the cell by microtubule organizing centers (MTOCs) pushing and pulling on centromeres of both chromatids thereby causing the chromosome to move to the center. At this point the chromosomes are still condensing and are currently one step away from being the most coiled and condensed they will be, and the spindle fibers have already connected to the kinetochores. During this phase all the microtubules, with the exception of the kinetochores, are in a state of instability promoting their progression toward anaphase. At this point, the chromosomes are ready to split into opposite poles of the cell toward the spindle to which they are connected. | https://en.wikipedia.org/wiki/Cell_division |
In metaphysical terms, the Copenhagen interpretation views quantum mechanics as providing knowledge of phenomena, but not as pointing to 'really existing objects', which it regards as residues of ordinary intuition. This makes it an epistemic theory. This may be contrasted with Einstein's view, that physics should look for 'really existing objects', making itself an ontic theory.The metaphysical question is sometimes asked: "Could quantum mechanics be extended by adding so-called "hidden variables" to the mathematical formalism, to convert it from an epistemic to an ontic theory?" The Copenhagen interpretation answers this with a strong 'No'. | https://en.wikipedia.org/wiki/Copenhagen_interpretation |
It is sometimes alleged, for example by J.S. Bell, that Einstein opposed the Copenhagen interpretation because he believed that the answer to that question of "hidden variables" was "yes". By contrast, Max Jammer writes "Einstein never proposed a hidden variable theory." Einstein explored the possibility of a hidden variable theory, and wrote a paper describing his exploration, but withdrew it from publication because he felt it was faulty. | https://en.wikipedia.org/wiki/Copenhagen_interpretation |
In metaphysics and ontology, Austrian philosopher Alexius Meinong advanced nonexistent objects in the 19th and 20th centuries within a "theory of objects". He was interested in intentional states which are directed at nonexistent objects. Starting with the "principle of intentionality", mental phenomena are intentionally directed towards an object. People may imagine, desire or fear something that does not exist. Other philosophers concluded that intentionality is not a real relation and therefore does not require the existence of an object, while Meinong concluded there is an object for every mental state whatsoever—if not an existent then at least a nonexistent one. | https://en.wikipedia.org/wiki/Russellian_view |
In metaphysics and ontology, Austrian philosopher Alexius Meinong advanced nonexistent objects in the 19th and 20th century within a "theory of objects". He was interested in intentional states which are directed at nonexistent objects. Starting with the "principle of intentionality", mental phenomena are intentionally directed towards an object. People may imagine, desire or fear something that does not exist. Other philosophers concluded that intentionality is not a real relation and therefore does not require the existence of an object, while Meinong concluded there is an object for every mental state whatsoever—if not an existent then at least a nonexistent one. | https://en.wikipedia.org/wiki/Object_of_the_mind |
In metaphysics and philosophy of language, the correspondence theory of truth states that the truth or falsity of a statement is determined only by how it relates to the world and whether it accurately describes (i.e., corresponds with) that world.Correspondence theories claim that true beliefs and true statements correspond to the actual state of affairs. This type of theory attempts to posit a relationship between thoughts or statements on one hand, and things or facts on the other. | https://en.wikipedia.org/wiki/Correspondence_theory_of_truth |
In metaphysics and the philosophy of language, an empty name is a proper name that has no referent. The problem of empty names is the idea that empty names have a meaning when it seems they should not have. The name "Pegasus" is empty; there is nothing to which it refers. Yet, though there is no Pegasus, we know what the sentence "Pegasus has two wings" means. We can even understand the sentence "There is no such thing as Pegasus." But, what can the meaning of a proper name be, except the object to which it refers? | https://en.wikipedia.org/wiki/Empty_name |
In metaphysics there are many troubling questions pertaining to parts and wholes. One question addresses constitution and persistence, another asks about composition. | https://en.wikipedia.org/wiki/Mereology |
In metaphysics, Avicenna (Ibn Sina) defined truth as: What corresponds in the mind to what is outside it. Avicenna elaborated on his definition of truth in his Metaphysics: The truth of a thing is the property of the being of each thing which has been established in it. In his Quodlibeta, Thomas Aquinas wrote a commentary on Avicenna's definition of truth in his Metaphysics and explained it as follows: The truth of each thing, as Avicenna says in his Metaphysica, is nothing else than the property of its being which has been established in it. So that is called true gold which has properly the being of gold and attains to the established determinations of the nature of gold. | https://en.wikipedia.org/wiki/Islamic_philosophy |
Now, each thing has properly being in some nature because it stands under the complete form proper to that nature, whereby being and species in that nature is. Early Islamic political philosophy emphasized an inexorable link between science and religion and the process of ijtihad to find truth. Ibn al-Haytham (Alhacen) reasoned that to discover the truth about nature, it is necessary to eliminate human opinion and error, and allow the universe to speak for itself. | https://en.wikipedia.org/wiki/Islamic_philosophy |
In his Aporias against Ptolemy, Ibn al-Haytham further wrote the following comments on truth: Truth is sought for itself the truths, are immersed in uncertainties not immune from error... Therefore, the seeker after the truth is not one who studies the writings of the ancients and, following his natural disposition, puts his trust in them, but rather the one who suspects his faith in them and questions what he gathers from them, the one who submits to argument and demonstration, and not to the sayings of a human being whose nature is fraught with all kinds of imperfection and deficiency. Thus the duty of the man who investigates the writings of scientists, if learning the truth is his goal, is to make himself an enemy of all that he reads, and, applying his mind to the core and margins of its content, attack it from every side. He should also suspect himself as he performs his critical examination of it, so that he may avoid falling into either prejudice or leniency. I constantly sought knowledge and truth, and it became my belief that for gaining access to the effulgence and closeness to God, there is no better way than that of searching for truth and knowledge. | https://en.wikipedia.org/wiki/Islamic_philosophy |
In metaphysics, Mally is known for introducing a distinction between two kinds of predication, a strategy better known as the dual predication approach, for solving the problem of nonexistent objects (Mally 1912). He also introduced a similar strategy, the dual property strategy, but did not endorse it. The dual property strategy was eventually adopted by Meinong.Mally developed a realistic approach to ontology (Mally 1935) and saw himself in opposition to the Vienna Circle and the logical positivists. | https://en.wikipedia.org/wiki/Ernst_Mally |
In metaphysics, Plato's beard is a paradoxical argument dubbed by Willard Van Orman Quine in his 1948 paper "On What There Is". The phrase came to be identified as the philosophy of understanding something based on what does not exist. | https://en.wikipedia.org/wiki/Plato's_beard |
In metaphysics, Salmon sought a "process theory" of causality to model "causality without counterfactuals", yet meet the "Humean empirical strictures". Salmon criticized Bertrand Russell's theory of causal lines—forerunner of today's theories of causal processes—for involving the epistemic but neglecting the ontic, which causation is. Further, Hans Reichenbach had noted that Russell's causal lines must be distinguished from "unreal sequences": continuous phenomena that actually are not causal processes. Salmon's explanation of causal processes drew a number of criticisms, whereupon Salmon explained that causal processes and causal interactions are "the basic causal mechanisms", while causal interactions are more fundamental than causal processes, but causal processes were discussed first for practical reasons.Salmon explained causal processes as "the means by which causal influence is transmitted", and thus what "constitute precisely the objective physical causal connections which Hume sought in vain". | https://en.wikipedia.org/wiki/Wesley_C._Salmon |
Salmon explained that causal processes can transmit a mark or can transmit structure in a way continuous spatiotemporally. Thereby, the marking principle sorts causal processes from pseudo processes (Reichenbach's "unreal sequences"). | https://en.wikipedia.org/wiki/Wesley_C._Salmon |
Marking a causal process modifies it, a mark not transmitted by a pseudo process. Meanwhile, causal forks are "the means by which causal structure is generated and modified". Others have found Salmon's theory of mark transmission to have shortcomings, however, whereby it can fail to discern causal processes from pseudo processes. | https://en.wikipedia.org/wiki/Wesley_C._Salmon |
In metaphysics, a universal is a proposed type, property, or relation which can be instantiated by many different particulars. While universals are related to the concept of universality, the concept is importantly distinct; see the main page on universals for a full treatment of the topic. | https://en.wikipedia.org/wiki/Absolute_truth |
In metaphysics, a universal is what particular things have in common, namely characteristics or qualities. In other words, universals are repeatable or recurrent entities that can be instantiated or exemplified by many particular things. For example, suppose there are two chairs in a room, each of which is green. These two chairs both share the quality of "chairness", as well as greenness or the quality of being green; in other words, they share two "universals". | https://en.wikipedia.org/wiki/Universal_(metaphysics) |
There are three major kinds of qualities or characteristics: types or kinds (e.g. mammal), properties (e.g. short, strong), and relations (e.g. father of, next to). These are all different types of universals.Paradigmatically, universals are abstract (e.g. humanity), whereas particulars are concrete (e.g. the personhood of Socrates). | https://en.wikipedia.org/wiki/Universal_(metaphysics) |
However, universals are not necessarily abstract and particulars are not necessarily concrete. For example, one might hold that numbers are particular yet abstract objects. Likewise, some philosophers, such as D. M. Armstrong, consider universals to be concrete. Most do not consider classes to be universals, although some prominent philosophers do, such as John Bigelow. | https://en.wikipedia.org/wiki/Universal_(metaphysics) |
In metaphysics, conceptualism is a theory that explains universality of particulars as conceptualized frameworks situated within the thinking mind. Intermediate between nominalism and realism, the conceptualist view approaches the metaphysical concept of universals from a perspective that denies their presence in particulars outside the mind's perception of them. Conceptualism is anti-realist about abstract objects, just like immanent realism is (their difference being that immanent realism accepts there are mind-independent facts about whether universals are instantiated). | https://en.wikipedia.org/wiki/Perceptual_nonconceptualism |
In metaphysics, extension signifies both 'stretching out' (Latin: extensio) as well as later 'taking up space', and most recently, spreading one's internal mental cognition into the external world. The history of thinking about extension can be traced back at least to Archytas' spear analogy for the infinity of space. How far can one's hand or spear stretch out until it reaches the edge of reality? “If I arrived at the outermost edge of the heaven, could I extend my hand or staff into what is outside or not? It would be paradoxical not to be able to extend it.” | https://en.wikipedia.org/wiki/Extension_(metaphysics) |
In metaphysics, nominalism is the view that universals and abstract objects do not actually exist other than being merely names or labels. There are at least two main versions of nominalism. One version denies the existence of universals – things that can be instantiated or exemplified by many particular things (e.g., strength, humanity). The other version specifically denies the existence of abstract objects – objects that do not exist in space and time.Most nominalists have held that only physical particulars in space and time are real, and that universals exist only post res, that is, subsequent to particular things. | https://en.wikipedia.org/wiki/Medieval_nominalism |
However, some versions of nominalism hold that some particulars are abstract entities (e.g., numbers), while others are concrete entities – entities that do exist in space and time (e.g., pillars, snakes, bananas). Nominalism is primarily a position on the problem of universals. | https://en.wikipedia.org/wiki/Medieval_nominalism |
It is opposed to realist philosophies, such as Platonic realism, which assert that universals do exist over and above particulars, and to the hylomorphic substance theory of Aristotle, which asserts that universals are immanently real within them. However, the name "nominalism" emerged from debates in medieval philosophy with Roscellinus. The term nominalism stems from the Latin nomen, "name". John Stuart Mill summarised nominalism in the apothegm "there is nothing general except names".In philosophy of law, nominalism finds its application in what is called constitutional nominalism. | https://en.wikipedia.org/wiki/Medieval_nominalism |
In metaphysics, object-oriented ontology (OOO) is a 21st-century Heidegger-influenced school of thought that rejects the privileging of human existence over the existence of nonhuman objects. This is in contrast to what it calls the "anthropocentrism" of Kant's philosophy by proposing a metaphorical Copernican Revolution, which would displace the human from the center of the universe like Copernicus displaced the Earth from being the center of the universe. Object-oriented ontology maintains that objects exist independently (as Kantian noumena) of human perception and are not ontologically exhausted by their relations with humans or other objects. For object-oriented ontologists, all relations, including those between nonhumans, distort their related objects in the same basic manner as human consciousness and exist on an equal footing with one another.Object-oriented ontology is often viewed as a subset of speculative realism, a contemporary school of thought that criticizes the post-Kantian reduction of philosophical enquiry to a correlation between thought and being (correlationism), such that the reality of anything outside of this correlation is unknowable. | https://en.wikipedia.org/wiki/Object-oriented_ontology |
Object-oriented ontology predates speculative realism, however, and makes distinct claims about the nature and equality of object relations to which not all speculative realists agree. The term "object-oriented philosophy" was coined by Graham Harman, the movement's founder, in his 1999 doctoral dissertation "Tool-Being: Elements in a Theory of Objects". In 2009, Levi Bryant rephrased Harman's original designation as "object-oriented ontology", giving the movement its current name. | https://en.wikipedia.org/wiki/Object-oriented_ontology |
In metaphysics, ontology is the philosophical study of being. It investigates what types of entities exist, how they are grouped into categories, and how they are related to one another on the most fundamental level. Ontologists often try to determine what the categories or highest kinds are and how they form a system of categories that encompasses the classification of all entities. Commonly proposed categories include substances, properties, relations, states of affairs, and events. | https://en.wikipedia.org/wiki/Eleatic_principle |
These categories are characterized by fundamental ontological concepts, including particularity and universality, abstractness and concreteness, or possibility and necessity. Of special interest is the concept of ontological dependence, which determines whether the entities of a category exist on the most fundamental level. | https://en.wikipedia.org/wiki/Eleatic_principle |
Disagreements within ontology are often about whether entities belonging to a certain category exist and, if so, how they are related to other entities.When used as a countable noun, the words ontology and ontologies refer not to the science of being but to theories within the science of being. Ontological theories can be divided into various types according to their theoretical commitments. Monocategorical ontologies hold that there is only one basic category, but polycategorical ontologies rejected this view. Hierarchical ontologies assert that some entities exist on a more fundamental level and that other entities depend on them. Flat ontologies, on the other hand, deny such a privileged status to any entity. | https://en.wikipedia.org/wiki/Eleatic_principle |
In metaphysics, phenomenalism is the view that physical objects cannot justifiably be said to exist in themselves, but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in space. In particular, some forms of phenomenalism reduce all talk about physical objects in the external world to talk about bundles of sense data. | https://en.wikipedia.org/wiki/Phenomenalism |
In metaphysics, the A series and the B series are two different descriptions of the temporal ordering relation among events. The two series differ principally in their use of tense to describe the temporal relation between events and the resulting ontological implications regarding time. John McTaggart introduced these terms in 1908, in an argument for the unreality of time. They are now commonly used by contemporary philosophers of time. | https://en.wikipedia.org/wiki/A_series_and_B_series |
In metaphysics, the distinction between abstract and concrete refers to a divide between two types of entities. Many philosophers hold that this difference has fundamental metaphysical significance. Examples of concrete objects include plants, human beings and planets while things like numbers, sets and propositions are abstract objects. There is no general consensus as to what the characteristic marks of concreteness and abstractness are. | https://en.wikipedia.org/wiki/Abstract_objects |
Popular suggestions include defining the distinction in terms of the difference between (1) existence inside or outside space-time, (2) having causes and effects or not, (3) having contingent or necessary existence, (4) being particular or universal and (5) belonging to either the physical or the mental realm or to neither. Despite this diversity of views, there is broad agreement concerning most objects as to whether they are abstract or concrete. So under most interpretations, all these views would agree that, for example, plants are concrete objects while numbers are abstract objects. | https://en.wikipedia.org/wiki/Abstract_objects |
Abstract objects are most commonly used in philosophy and semantics. They are sometimes called abstracta in contrast to concreta. The term abstract object is said to have been coined by Willard Van Orman Quine. | https://en.wikipedia.org/wiki/Abstract_objects |
Abstract object theory is a discipline that studies the nature and role of abstract objects. It holds that properties can be related to objects in two ways: through exemplification and through encoding. Concrete objects exemplify their properties while abstract objects merely encode them. This approach is also known as the dual copula strategy. | https://en.wikipedia.org/wiki/Abstract_objects |
In metaphysics, the multiple occupancy view (m.o.) is a particular analysis of fission cases, which claims to be at least a priori possible, if not actually true of real cases of fission. | https://en.wikipedia.org/wiki/Multiple_occupancy_view |
In metaphysics, there are several puzzles concerning cases of mereological constitution, that is, what makes up a whole. There is still a concern with parts and wholes, but instead of looking at what parts make up a whole, the emphasis is on what a thing is made of, such as its materials, e.g., the bronze in a bronze statue. Below are two of the main puzzles that philosophers use to discuss constitution. Ship of Theseus: Briefly, the puzzle goes something like this. | https://en.wikipedia.org/wiki/Mereology |
There is a ship called the Ship of Theseus. Over time, the boards start to rot, so we remove the boards and place them in a pile. First question, is the ship made of the new boards the same as the ship that had all the old boards? | https://en.wikipedia.org/wiki/Mereology |
Second, if we reconstruct a ship using all of the old planks, etc. from the Ship of Theseus, and we also have a ship that was built out of new boards (each added one-by-one over time to replace old decaying boards), which ship is the real Ship of Theseus? Statue and Lump of Clay: Roughly, a sculptor decides to mold a statue out of a lump of clay. At time t1 the sculptor has a lump of clay. | https://en.wikipedia.org/wiki/Mereology |
After many manipulations at time t2 there is a statue. The question asked is, is the lump of clay and the statue (numerically) identical? If so, how and why?Constitution typically has implications for views on persistence: how does an object persist over time if any of its parts (materials) change or are removed, as is the case with humans who lose cells, change height, hair color, memories, and yet we are said to be the same person today as we were when we were first born. | https://en.wikipedia.org/wiki/Mereology |
For example, Ted Sider is the same today as he was when he was born—he just changed. But how can this be if many parts of Ted today did not exist when Ted was just born? Is it possible for things, such as organisms to persist? | https://en.wikipedia.org/wiki/Mereology |
And if so, how? There are several views that attempt to answer this question. Some of the views are as follows (note, there are several other views):(a) Constitution view. | https://en.wikipedia.org/wiki/Mereology |
This view accepts cohabitation. That is, two objects share exactly the same matter. Here, it follows, that there are no temporal parts. | https://en.wikipedia.org/wiki/Mereology |
(b) Mereological essentialism, which states that the only objects that exist are quantities of matter, which are things defined by their parts. The object persists if matter is removed (or the form changes); but the object ceases to exist if any matter is destroyed. (c) Dominant Sorts. | https://en.wikipedia.org/wiki/Mereology |
This is the view that tracing is determined by which sort is dominant; they reject cohabitation. For example, lump does not equal statue because they're different "sorts". | https://en.wikipedia.org/wiki/Mereology |
(d) Nihilism—which makes the claim that no objects exist, except simples, so there is no persistence problem. (e) 4-dimensionalism or temporal parts (may also go by the names perdurantism or exdurantism), which roughly states that aggregates of temporal parts are intimately related. | https://en.wikipedia.org/wiki/Mereology |
For example, two roads merging, momentarily and spatially, are still one road, because they share a part. (f) 3-dimensionalism (may also go by the name endurantism), where the object is wholly present. That is, the persisting object retains numerical identity. | https://en.wikipedia.org/wiki/Mereology |
In metazoans the increase in the rate of histone synthesis is due to the increase in processing of pre-mRNA to its mature form as well as decrease in mRNA degradation; this results in an increase of active mRNA for translation of histone proteins. The mechanism for mRNA activation has been found to be the removal of a segment of the 3' end of the mRNA strand, and is dependent on association with stem-loop binding protein (SLBP). SLBP also stabilizes histone mRNAs during S phase by blocking degradation by the 3'hExo nuclease. | https://en.wikipedia.org/wiki/Histone_modification |
SLBP levels are controlled by cell-cycle proteins, causing SLBP to accumulate as cells enter S phase and degrade as cells leave S phase. SLBP are marked for degradation by phosphorylation at two threonine residues by cyclin dependent kinases, possibly cyclin A/ cdk2, at the end of S phase. Metazoans also have multiple copies of histone genes clustered on chromosomes which are localized in structures called Cajal bodies as determined by genome-wide chromosome conformation capture analysis (4C-Seq). | https://en.wikipedia.org/wiki/Histone_modification |
In metazoans, in order to respond to environmental stress, differentiate properly, and progress normally through the cell cycle, a eukaryotic cell needs a specific and coordinated gene expression program, which involves the highly regulated transcription of thousands of genes. This gene regulation is in large part controlled, in a tissue-specific manner, by the binding of transcription factors to noncoding genomic regions referred to as cis-regulatory modules (CRMs), activating or repressing gene expression by modulating the structure of the chromatin and therefore having a positive or negative effect on transcription regulation. CRMs activating gene expression are often referred to as transcriptional enhancers, whereas those repressing gene expression are referred to as transcriptional silencers. | https://en.wikipedia.org/wiki/Enhancer-FACS-seq |
In metazoans, small interfering RNAs (siRNAs) processed by Dicer are incorporated into a complex known as the RNA-induced silencing complex or RISC. This complex contains an endonuclease that cleaves perfectly complementary messages to which the siRNA binds. The resulting mRNA fragments are then destroyed by exonucleases. siRNA is commonly used in laboratories to block the function of genes in cell culture. It is thought to be part of the innate immune system as a defense against double-stranded RNA viruses. | https://en.wikipedia.org/wiki/Polycistronic_mRNA |
In meteorites and in prebiotic experiments (e.g. Miller–Urey experiment) many more amino acids than the twenty standard amino acids are found, several of which at higher concentrations than the standard ones: it has been conjectured that if amino acid based life were to arise in parallel elsewhere in the universe, no more than 75% of the amino acids would be in common. The most notable anomaly is the lack of aminobutyric acid. | https://en.wikipedia.org/wiki/Non-proteinogenic_amino_acids |
In meteorites, ringwoodite occurs in the veinlets of quenched shock-melt cutting the matrix and replacing olivine probably produced during shock metamorphism.In Earth's interior, olivine occurs in the upper mantle at depths less than about 410 km, and ringwoodite is inferred to be present within the transition zone from about 520 to 660 km depth. Seismic activity discontinuities at about 410 km, 520 km, and at 660 km depth have been attributed to phase changes involving olivine and its polymorphs. The 520-km depth discontinuity is generally believed to be caused by the transition of the olivine polymorph wadsleyite (beta-phase) to ringwoodite (gamma-phase), while the 660-km depth discontinuity by the phase transformation of ringwoodite (gamma-phase) to a silicate perovskite plus magnesiowüstite.Ringwoodite in the lower half of the transition zone is inferred to play a pivotal role in mantle dynamics, and the plastic properties of ringwoodite are thought to be critical in determining flow of material in this part of the mantle. The ability of ringwoodite to incorporate hydroxide is important because of its effect on rheology. | https://en.wikipedia.org/wiki/Ringwoodite |
Ringwoodite has been synthesized at conditions appropriate to the transition zone, containing up to 2.6 weight percent water.Because the transition zone between the Earth's upper and lower mantle helps govern the scale of mass and heat transport throughout the Earth, the presence of water within this region, whether global or localized, may have a significant effect on mantle rheology and therefore mantle circulation. In subduction zones, the ringwoodite stability field hosts high levels of seismicity.An "ultradeep" diamond (one that has risen from a great depth) found in Juína in western Brazil contained an inclusion of ringwoodite — at the time the only known sample of natural terrestrial origin — thus providing evidence of significant amounts of water as hydroxide in the Earth's mantle. The gemstone, about 5mm long, was brought up by a diatreme eruption. The ringwoodite inclusion is too small to see with the naked eye. A second such diamond was later found.The mantle reservoir could contain about three times more water, in the form of hydroxide contained within the wadsleyite and ringwoodite crystal structure, than the Earth's oceans combined. | https://en.wikipedia.org/wiki/Ringwoodite |
In meteoritics, a meteorite classification system attempts to group similar meteorites and allows scientists to communicate with a standardized terminology when discussing them. Meteorites are classified according to a variety of characteristics, especially mineralogical, petrological, chemical, and isotopic properties. | https://en.wikipedia.org/wiki/Meteorites_classification |
In meteoritics, a parent body is the celestial body from which originates a meteorite or a class of meteorites. | https://en.wikipedia.org/wiki/Parent_body |
In meteorological applications, a zonal wavenumber or hemispheric wavenumber is the dimensionless number of wavelengths fitting within a full circle around the globe at a given latitude. k = 2 π r cos φ λ {\displaystyle k={\frac {2\pi r\cos \varphi }{\lambda }}} where λ is the wavelength, r is the Earth's radius, and φ {\displaystyle \varphi } is the latitude. Zonal wavenumbers are typically counted on the upper level (say 500-millibar) geopotential maps by identifying troughs and ridges of the waves. Wavenumber 1 has one trough and one ridge, i.e. one wavelength fits 2 π = 360 {\displaystyle 2\pi =360} degrees. | https://en.wikipedia.org/wiki/Zonal_wavenumber |
Wavenumber 2 has two ridges and two troughs around 360 degrees. Wavenumber 0 corresponds to zonal (symmetric) flow. Wavenumbers 1–3 are called long waves and often synonymous in meteorological literature with the mid-latitude planetary Rossby waves, while wavenumbers 4-10 are often referred to as "synoptic" waves. In the Northern Hemisphere, wavenumbers 1 and 2 are important for the time-mean circulation due to topography (Tibetan Plateau and Rocky Mountains), whereas in the Southern Hemisphere, tropical convection is responsible for the presence of mainly zonal wavenumber 3. | https://en.wikipedia.org/wiki/Zonal_wavenumber |
In meteorological applications, whole sky cameras are used to study cloud cover, the current level of UV radiation, fractional cloud coverage, sky polarization, the computation of cloud base height and wind speed at cloud heights. Other uses include creating time-lapse photography of clouds. Whole sky cameras may be equipped with a sun tracking device to block sunlight which is too bright for the typical dynamic range of photographs. Sun tracking allows for reliable estimates of cloud fractional coverage, including cover in the part of the sky close to the Sun. There are techniques such as HDR which permit the taking of high dynamic range photographs without a sun tracker. | https://en.wikipedia.org/wiki/Whole_sky_camera |
In meteorological terms, the solstices (the maximum and minimum insolation) do not fall in the middles of summer and winter. The heights of these seasons occur up to 7 weeks later because of seasonal lag. Seasons, though, are not always defined in meteorological terms. | https://en.wikipedia.org/wiki/Season |
In astronomical reckoning by hours of daylight alone, the solstices and equinoxes are in the middle of the respective seasons. Because of seasonal lag due to thermal absorption and release by the oceans, regions with a continental climate, which predominate in the Northern Hemisphere, often consider these four dates to be the start of the seasons as in the diagram, with the cross-quarter days considered seasonal midpoints. The length of these seasons is not uniform because of Earth's elliptical orbit and its different speeds along that orbit. | https://en.wikipedia.org/wiki/Season |
In meteorology a ridge or barometric ridge is an elongated area of relatively high atmospheric pressure compared to the surrounding environment, without being a closed circulation. It is associated with an area of maximum anticyclonic curvature of wind flow. The ridge originates in the center of an anticyclone and sandwiched between two low-pressure areas, and the locus of the maximum curvature is called the ridge line. This phenomenon is the opposite of a trough. | https://en.wikipedia.org/wiki/Ridge_(meteorology) |
In meteorology and physical oceanography, advection often refers to the horizontal transport of some property of the atmosphere or ocean, such as heat, humidity or salinity, and convection generally refers to vertical transport (vertical advection). Advection is important for the formation of orographic clouds (terrain-forced convection) and the precipitation of water from clouds, as part of the hydrological cycle. | https://en.wikipedia.org/wiki/Advection |
In meteorology the Ellrod index is a technique for forecasting clear-air turbulence (CAT). It is calculated based on the product of horizontal deformation and vertical wind shear derived from numerical model forecast winds aloft. The deformation predictors are calculated using following information. Shearing deformation: D S H = d v d x + d u d y {\displaystyle DSH={\frac {dv}{dx}}+{\frac {du}{dy}}} .Stretching deformation: D S T = d u d x − d v d y {\displaystyle DST={\frac {du}{dx}}-{\frac {dv}{dy}}} .Where u and v are horizontal components of the wind. Total deformation equals to: D E F = D S H 2 + D S T 2 {\displaystyle DEF={\sqrt {DSH^{2}+DST^{2}}}} .Convergence: C V G = − ( d u d x + d v d y ) {\displaystyle CVG=-({\frac {du}{dx}}+{\frac {dv}{dy}})} Vertical wind shear: V W S = Δ V Δ Z {\displaystyle VWS={\frac {\Delta V}{\Delta Z}}} And the resulting index is given by: E I = V W S × ( D E F + C V G ) {\displaystyle EI=VWS\times (DEF+CVG)} To correspond to clear-air turbulence pilot reports the following table can be used: | https://en.wikipedia.org/wiki/Ellrod_index |
In meteorology, Altocumulus castellanus or Altocumulus castellatus (ACCAS) is a cloud type named for its tower-like projections that billow upwards from the base of the cloud. The base of the cloud can form as low as 2,000 metres (6,500 feet), or as high as 6,000 metres (20,000 feet). They are very similar to cumulus congestus clouds, but at a higher level and with the cloud heaps joined at the base. Castellanus clouds are evidence of mid-atmospheric instability and a high mid-altitude lapse rate. | https://en.wikipedia.org/wiki/Altocumulus_castellanus_cloud |
They may be a harbinger of heavy showers and thunderstorms and, if surface-based convection can connect to the mid-tropospheric unstable layer, continued development of Castellanus clouds can produce cumulonimbus clouds. Altocumulus castellanus clouds are typically accompanied by moderate turbulence as well as potential icing conditions. For these reasons, flight through these clouds is often best avoided by aircraft. | https://en.wikipedia.org/wiki/Altocumulus_castellanus_cloud |
In meteorology, Buys Ballot's law (Dutch pronunciation: ) may be expressed as follows: In the Northern Hemisphere, if a person stands with their back to the wind, the atmospheric pressure is low to the left, high to the right. This is because wind travels counterclockwise around low pressure zones in the Northern Hemisphere. It is approximately true in the higher latitudes of the Northern Hemisphere, and is reversed in the Southern Hemisphere, but the angle between the pressure gradient force and wind is not a right angle in low latitudes. A version taught to Naval Cadets in WW2 is: "In the Northern Hemisphere, if you turn your back to the wind, the low pressure center will be to your left and somewhat toward the front." (Aerology for Pilots, McGraw-Hill, 1943, pg 43) | https://en.wikipedia.org/wiki/Buys_Ballot's_law |
In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may compose the droplets and crystals. On Earth, clouds are formed as a result of saturation of the air when it is cooled to its dew point, or when it gains sufficient moisture (usually in the form of water vapor) from an adjacent source to raise the dew point to the ambient temperature. Clouds are seen in the Earth's homosphere, which includes the troposphere, stratosphere, and mesosphere. | https://en.wikipedia.org/wiki/Low_cloud |
Nephology is the science of clouds, which is undertaken in the cloud physics branch of meteorology. There are two methods of naming clouds in their respective layers of the homosphere, Latin and common name. Genus types in the troposphere, the atmospheric layer closest to Earth's surface, have Latin names because of the universal adoption of Luke Howard's nomenclature that was formally proposed in 1802. | https://en.wikipedia.org/wiki/Low_cloud |
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